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Sample records for evaporite karst development

  1. Karst in evaporites in southeastern New Mexico

    International Nuclear Information System (INIS)

    Bachman, G.O.

    1987-09-01

    Permian evaporites in southeastern New Mexico include gypsum, anhydrite, and salt, which are subject to both blanket and local, selective dissolution. Dissolution has produced many hundreds of individual karst features including collapse sinks, karst valleys, blind valleys, karst plains, caves, and breccia pipes. Dissolution began within some formations during Permian time and has been intermittent but continual ever since. Karst features other than blanket deposits of breccia are not preserved from the early episodes of dissolution, but some karst features preserved today - such as breccia pipes - are remnants of karst activity that was active at least as early as mid-Pleistocene time. Rainfall was much more abundant during Late Pleistocene time, and many features visible today may have been formed then. The drainage history of the Pecos River is related to extensive karstification of the Pecos Valley during mid-Pleistocene time. Large-scale stream piracy and dissolution of salt in the subsurface resulted in major shifts and excavations in the channel. In spite of intensive groundwater studies that have been carried out in the region, major problems in near-surface evaporite karst remain to be solved. Among these are determination of recharge areas and time of recharge. 109 refs., 31 figs., 1 tab

  2. Evaporite karst of northern lower Michigan

    Science.gov (United States)

    Black, T.J.

    1997-01-01

    Michigan has three main zones of evaporite karst: collapse breccia in Late Silurian deposits of the Mackinac Straits region; breccia, collapse sinks, and mega-block collapse in Middle Devonian deposits of Northern Lower Michigan, which overlaps the preceding area; and areas of soil swallows in sinks of Mississippian deposits between Turner and Alabaster in Arenac and Iosco counties, and near Grand Rapids in Kent County. The author has focused his study on evaporite karst of the Middle Devonian deposits. The Middle Devonian depos its are the Detroit River Group: a series consisting of limestone, dolomite, shale, salt, gypsum, and anhydrite. The group occurs from subcrop, near the surface, to nearly 1400 feet deep from the northern tip of the Southern Peninsula to the south edge of the "solution front" Glacial drift is from zero to 350 feet thick. Oil and gas exploration has encountered some significant lost-circulation zones throughout the area. Drilling without fluid returns, casing-seal failures, and lost holes are strong risks in some parts of the region. Lost fluid returns near the top of the group in nearby areas indicate some karst development shortly after deposition. Large and irregular lost-circulation zones, linear and patch trends of large sink holes, and 0.25 mile wide blocks of down-dropped land in the northern Lower Peninsula of Michigan were caused by surface- and ground-water movement along faults into the Detroit River Group. Glaciation has removed some evidence of the karst area at the surface. Sinkhole development, collapse valleys, and swallows developed since retreat of the glacier reveal an active solution front in the Detroit River Group.

  3. Evaporite karst geohazards in the Delaware Basin, Texas: review of traditional karst studies coupled with geophysical and remote sensing characterization

    Directory of Open Access Journals (Sweden)

    Kevin W. Stafford

    2017-06-01

    Full Text Available Evaporite karst throughout the Gypsum Plain of west Texas is complex and extensive, including manifestations ranging from intrastratal brecciation and hypogene caves to epigene features and suffosion caves. Recent advances in hydrocarbon exploration and extraction has resulted in increased infrastructure development and utilization in the area; as a result, delineation and characterization of potential karst geohazards throughout the region have become a greater concern. While traditional karst surveys are essential for delineating the subsurface extent and morphology of individual caves for speleogenetic interpretation, these methods tend to underestimate the total extent of karst development and require surficial manifestation of karst phenomena. Therefore, this study utilizes a composite suite of remote sensing and traditional field studies for improved karst delineation and detection of potential karst geohazards within gypsum karst. Color InfraRed (CIR imagery were utilized for delineation of lineaments associated with fractures, while Normalized Density Vegetation Index (NDVI analyses were used to delineate regions of increased moisture flux and probable zones of shallow karst development. Digital Elevation Models (DEM constructed from high-resolution LiDAR (Light Detection and Ranging data were used to spatially interpret sinkholes, while analyses of LiDAR intensity data were used in a novel way to categorize local variations in surface geology. Resistivity data, including both direct current (DC and capacitively coupled (CC resistivity analyses, were acquired and interpreted throughout the study area to delineate potential shallow karst geohazards specifically associated with roadways of geohazard concern; however, detailed knowledge of the surrounding geology and local karst development proved essential for proper interpretation of resistivity inversions. The composite suite of traditional field investigations and remotely sensed karst

  4. Identification, prediction, and mitigation of sinkhole hazards in evaporite karst areas

    Science.gov (United States)

    Gutierrez, F.; Cooper, A.H.; Johnson, K.S.

    2008-01-01

    Sinkholes usually have a higher probability of occurrence and a greater genetic diversity in evaporite terrains than in carbonate karst areas. This is because evaporites have a higher solubility and, commonly, a lower mechanical strength. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes are only well understood in a few areas. To deal with these hazards, a phased approach is needed for sinkhole identification, investigation, prediction, and mitigation. Identification techniques include field surveys and geomorphological mapping combined with accounts from local people and historical sources. Detailed sinkhole maps can be constructed from sequential historical maps, recent topographical maps, and digital elevation models (DEMs) complemented with building-damage surveying, remote sensing, and high-resolution geodetic surveys. On a more detailed level, information from exposed paleosubsidence features (paleokarst), speleological explorations, geophysical investigations, trenching, dating techniques, and boreholes may help in investigating dissolution and subsidence features. Information on the hydrogeological pathways including caves, springs, and swallow holes are particularly important especially when corroborated by tracer tests. These diverse data sources make a valuable database-the karst inventory. From this dataset, sinkhole susceptibility zonations (relative probability) may be produced based on the spatial distribution of the features and good knowledge of the local geology. Sinkhole distribution can be investigated by spatial distribution analysis techniques including studies of preferential elongation, alignment, and nearest neighbor analysis. More objective susceptibility models may be obtained by analyzing the statistical relationships between the known sinkholes and the conditioning factors. Chronological information on sinkhole formation is required to estimate the probability of

  5. The impact of droughts and climate change on sinkhole occurrence. A case study from the evaporite karst of the Fluvia Valley, NE Spain.

    Science.gov (United States)

    Linares, Rogelio; Roqué, Carles; Gutiérrez, Francisco; Zarroca, Mario; Carbonel, Domingo; Bach, Joan; Fabregat, Ivan

    2017-02-01

    This work introduces the concept that sinkhole frequency in some karst settings increases during drought periods. This conception is tested in a sector of the Fluvia River valley in NE Spain, where subsidence phenomena is related to the karstification of folded Eocene evaporite formations. In the discharge areas, the evaporites behave as confined aquifers affected by hypogene karstification caused by aggressive artesian flows coming form an underlying carbonate aquifer. A sinkhole inventory with chronological data has been constructed, revealing temporal clusters. Those clusters show a good correlation with drought periods, as revealed by precipitation, river discharge and piezometric data. This temporal association is particularly obvious for the last and current drought starting in 1998, which is the most intense of the record period (1940-present). Climatic projections based on recent studies foresee an intensification of the droughts in this sector of NE Spain, which could be accompanied by the enhancement of the sinkhole hazard and the associated risks. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The current status of mapping karst areas and availability of public sinkhole-risk resources in karst terrains of the United States

    Science.gov (United States)

    Kuniansky, Eve L.; Weary, David J.; Kaufmann, James E.

    2016-01-01

    Subsidence from sinkhole collapse is a common occurrence in areas underlain by water-soluble rocks such as carbonate and evaporite rocks, typical of karst terrain. Almost all 50 States within the United States (excluding Delaware and Rhode Island) have karst areas, with sinkhole damage highest in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. A conservative estimate of losses to all types of ground subsidence was $125 million per year in 1997. This estimate may now be low, as review of cost reports from the last 15 years indicates that the cost of karst collapses in the United States averages more than $300 million per year. Knowing when a catastrophic event will occur is not possible; however, understanding where such occurrences are likely is possible. The US Geological Survey has developed and maintains national-scale maps of karst areas and areas prone to sinkhole formation. Several States provide additional resources for their citizens; Alabama, Colorado, Florida, Indiana, Iowa, Kentucky, Minnesota, Missouri, Ohio, and Pennsylvania maintain databases of sinkholes or karst features, with Florida, Kentucky, Missouri, and Ohio providing sinkhole reporting mechanisms for the public.

  7. Karst in the United States: a digital map compilation and database

    Science.gov (United States)

    Weary, David J.; Doctor, Daniel H.

    2014-01-01

    This report describes new digital maps delineating areas of the United States, including Puerto Rico and the U.S. Virgin Islands, having karst or the potential for development of karst and pseudokarst. These maps show areas underlain by soluble rocks and also by volcanic rocks, sedimentary deposits, and permafrost that have potential for karst or pseudokarst development. All 50 States contain rocks with potential for karst development, and about 18 percent of their area is underlain by soluble rocks having karst or the potential for development of karst features. The areas of soluble rocks shown are based primarily on selection from State geologic maps of rock units containing significant amounts of carbonate or evaporite minerals. Areas underlain by soluble rocks are further classified by general climate setting, degree of induration, and degree of exposure. Areas having potential for volcanic pseudokarst are those underlain chiefly by basaltic-flow rocks no older than Miocene in age. Areas with potential for pseudokarst features in sedimentary rocks are in relatively unconsolidated rocks from which pseudokarst features, such as piping caves, have been reported. Areas having potential for development of thermokarst features, mapped exclusively in Alaska, contain permafrost in relatively thick surficial deposits containing ground ice. This report includes a GIS database with links from the map unit polygons to online geologic unit descriptions.

  8. Epigene and Hypogene Gypsum Karst Manifestations of the Castile Formation: Eddy County, New Mexico and Culberson County, Texas, USA

    Directory of Open Access Journals (Sweden)

    Stafford Kevin W.

    2008-07-01

    Full Text Available Permian evaporites of the Castile Formation crop out over ~1,800 km2 in the western Delaware Basin (Eddy County, New Mexico and Culberson County, Texas, USA with abundant and diverse karst manifestations. Epigene karst occurs as well-developed karren on exposed bedrock, while sinkholes dominate the erosional landscape, including both solutional and collapse forms. Sinkhole analyses suggest that more than half of all sinks are the result of upward stoping of subsurface voids, while many solutional sinks are commonly the result of overprinting of collapsed forms. Epigene caves are laterally limited with rapid aperture decreases away from insurgence, with passages developed along fractures and anticline fold axes. Hypogene karst occurs as diverse manifestations, forming the deepest and longest caves within the region as well as abundant zones of brecciation. Hypogene caves exhibit a wide range of morphologies from complex maze and anastomotic patterns to simple, steeply dipping patterns, but all hypogene caves exhibit morphologic features (i.e. risers, outlet cupolas and half-tubes that provide a definitive suite of evidence of dissolution within a mixed convection (forced and free convection hydrologic system. Extensive blanket breccias, abundant breccia pipes and numerous occurrences of calcitized evaporites indicate widespread hypogene speleogenesis throughout the entire Castile Formation. Although most cave and karst development within the Castile outcrop region appears to have hypogene origins, epigene processes areactively overprinting features, creating a complex speleogenetic evolution within the Castile Formation.

  9. Sulphate rocks as an arena for karst development

    Directory of Open Access Journals (Sweden)

    Andrejchuk V.

    1996-01-01

    Full Text Available The rocks in which karst systems develop are most commonly composed of carbonate sulphate and chloride minerals. The sulphate minerals are quite numerous, but only gypsum and anhydrite form extensive masses in sedimentary sequences. Other minerals, which represent sulphates of K, Mg and Na, normally occur as minor beds (0.1-5.0 m, or as inclusions associated with chloride rocks. However some minerals precipitated in salt-generating basins, such as mirabilite and glauberite (typically formed in the Kara-Bogaz-Gol Gulf, salt lakes of Siberia and in China, form sequences up to 5-10 m thick where karst may develop. Due to the very high solubility of Na -sulphates, karst processes and features occurring in these rocks resemble salt karst. Thus, the term sulphate karst, although not strictly correct, is used mainly to indicate karst developed in gypsum and anhydrite.

  10. Assessment of the potential for karst in the Rustler Formation at the WIPP site

    International Nuclear Information System (INIS)

    Lorenz, John Clay

    2006-01-01

    This report is an independent assessment of the potential for karst dissolution in evaporitic strata of the Rustler Formation at the Waste Isolation Pilot Plant (WIPP) site. Review of the available data suggests that the Rustler strata thicken and thin across the area in depositional patterns related to lateral variations in sedimentary accommodation space and normal facies changes. Most of the evidence that has been offered for the presence of karst in the subsurface has been used out of context, and the different pieces are not mutually supporting. Outside of Nash Draw, definitive evidence for the development of karst in the Rustler Formation near the WIPP site is limited to the horizon of the Magenta Member in drillhole WIPP-33. Most of the other evidence cited by the proponents of karst is more easily interpreted as primary sedimentary structures and the localized dissolution of evaporitic strata adjacent to the Magenta and Culebra water-bearing units. Some of the cited evidence is invalid, an inherited baggage from studies made prior to the widespread knowledge of modern evaporite depositional environments and prior to the existence of definitive exposures of the Rustler Formation in the WIPP shafts. Some of the evidence is spurious, has been taken out of context, or is misquoted. Lateral lithologic variations from halite to mudstone within the Rustler Formation under the WIPP site have been taken as evidence for the dissolution of halite such as that seen in Nash Draw, but are more rationally explained as sedimentary facies changes. Extrapolation of the known karst features in Nash Draw eastward to the WIPP site, where conditions are and have been significantly different for half a million years, is unwarranted. The volumes of insoluble material that would remain after dissolution of halite would be significantly less than the observed bed thicknesses, thus dissolution is an unlikely explanation for the lateral variations from halite to mudstone and siltstone

  11. Assessment of the potential for karst in the Rustler Formation at the WIPP site.

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, John Clay

    2006-01-01

    This report is an independent assessment of the potential for karst dissolution in evaporitic strata of the Rustler Formation at the Waste Isolation Pilot Plant (WIPP) site. Review of the available data suggests that the Rustler strata thicken and thin across the area in depositional patterns related to lateral variations in sedimentary accommodation space and normal facies changes. Most of the evidence that has been offered for the presence of karst in the subsurface has been used out of context, and the different pieces are not mutually supporting. Outside of Nash Draw, definitive evidence for the development of karst in the Rustler Formation near the WIPP site is limited to the horizon of the Magenta Member in drillhole WIPP-33. Most of the other evidence cited by the proponents of karst is more easily interpreted as primary sedimentary structures and the localized dissolution of evaporitic strata adjacent to the Magenta and Culebra water-bearing units. Some of the cited evidence is invalid, an inherited baggage from studies made prior to the widespread knowledge of modern evaporite depositional environments and prior to the existence of definitive exposures of the Rustler Formation in the WIPP shafts. Some of the evidence is spurious, has been taken out of context, or is misquoted. Lateral lithologic variations from halite to mudstone within the Rustler Formation under the WIPP site have been taken as evidence for the dissolution of halite such as that seen in Nash Draw, but are more rationally explained as sedimentary facies changes. Extrapolation of the known karst features in Nash Draw eastward to the WIPP site, where conditions are and have been significantly different for half a million years, is unwarranted. The volumes of insoluble material that would remain after dissolution of halite would be significantly less than the observed bed thicknesses, thus dissolution is an unlikely explanation for the lateral variations from halite to mudstone and siltstone

  12. Karst database development in Minnesota: Design and data assembly

    Science.gov (United States)

    Gao, Y.; Alexander, E.C.; Tipping, R.G.

    2005-01-01

    The Karst Feature Database (KFD) of Minnesota is a relational GIS-based Database Management System (DBMS). Previous karst feature datasets used inconsistent attributes to describe karst features in different areas of Minnesota. Existing metadata were modified and standardized to represent a comprehensive metadata for all the karst features in Minnesota. Microsoft Access 2000 and ArcView 3.2 were used to develop this working database. Existing county and sub-county karst feature datasets have been assembled into the KFD, which is capable of visualizing and analyzing the entire data set. By November 17 2002, 11,682 karst features were stored in the KFD of Minnesota. Data tables are stored in a Microsoft Access 2000 DBMS and linked to corresponding ArcView applications. The current KFD of Minnesota has been moved from a Windows NT server to a Windows 2000 Citrix server accessible to researchers and planners through networked interfaces. ?? Springer-Verlag 2005.

  13. Sediment carbon fate in phreatic karst (Part 1): Conceptual model development

    Science.gov (United States)

    Husic, A.; Fox, J.; Agouridis, C.; Currens, J.; Ford, W.; Taylor, C.

    2017-06-01

    Recent research has paid increased attention to quantifying the fate of carbon pools within fluvial networks, but few, if any, studies consider the fate of sediment organic carbon in fluviokarst systems despite that karst landscapes cover 12% of the earth's land surface. The authors develop a conceptual model of sediment carbon fate in karst terrain with specific emphasis upon phreatic karst conduits, i.e., those located below the groundwater table that have the potential to trap surface-derived sediment and turnover carbon. To assist with their conceptual model development, the authors study a phreatic system and apply a mixture of methods traditional and novel to karst studies, including electrical resistivity imaging, well drilling, instantaneous velocimetry, dye tracing, stage recording, discrete and continuous sediment and water quality sampling, and elemental and stable carbon isotope fingerprinting. Results show that the sediment transport carrying capacity of the phreatic karst water is orders of magnitude less than surface streams during storm-activated periods promoting deposition of fine sediments in the phreatic karst. However, the sediment transport carrying capacity is sustained long after the hydrologic event has ended leading to sediment resuspension and prolonged transport. The surficial fine grained laminae occurs in the subsurface karst system; but unlike surface streams, the light-limited conditions of the subsurface karst promotes constant heterotrophy leading to carbon turnover. The coupling of the hydrological processes leads to a conceptual model that frames phreatic karst as a biologically active conveyor of sediment carbon that recharges degraded organic carbon back to surface streams. For example, fluvial sediment is estimated to lose 30% of its organic carbon by mass during a one year temporary residence within the phreatic karst. It is recommended that scientists consider karst pathways when attempting to estimate organic matter stocks

  14. Hydrogeochemistry of karst underground waters at shallow depth in Guiyang City, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    DONG Zhifen; ZHU Lijun; WU Pan; SHEN Zheng; FENG Zhiyong

    2005-01-01

    The aim of this study is to shed light on the hydrogeochemical characteristics of karst underground waters at shallow depth in Guiyang City, Guizhou Province with an emphasis on the geochemistry of major elements. Guiyang City bears abundant underground waters and it is also an important representative of the karst areas throughout the world. Ca 2+ and Mg 2+ are the dominant cations, accounting for 81%- 99.7% of the total, and HCO -3 and SO 2- 4 are the dominant anions. Weathering of limestones and dolostones is the most important factor controlling the hydrogeochemistry of underground waters, and weathering of sulfate and evaporite rocks is less important. Moreover, the precipitation and human activities also have a definite influence on the hydrogeochemistry of underground waters in the region studied.

  15. Karst in Slovenia; EL karst en Eslovenia

    Energy Technology Data Exchange (ETDEWEB)

    Mihevc, A.; Gabrovsek, F.; Knez, M.; Kozel, P.; Mulec, J.; Otomicar, B.; Petric, M.; Pipan, T.; Prelovsek, M.; Slabe, T.; Sebela, S.; Zupan Hajna, N.

    2016-07-01

    Karst is a type of landscape with special surface, underground and hydrological features and phenomena. Its main characteristic is dissolution of the carbonate rocks by water enriched with CO{sub 2} as the dominant morphological process, removal of the rock in the form of solution and prevalent underground drainage that forms caves. In Slovene language, kras means a rocky, barren surface developed on limestone or dolomite and is also used as a toponym, so the word karst was developed from the name of the Kras plateau, which is a classical, reference site for the karst type of landscape. (Author)

  16. Sustainable development of agriculture in karst areas, South China

    Directory of Open Access Journals (Sweden)

    Linhua Song

    1999-01-01

    Full Text Available The exposed carbonate rocks aged from Sinian to Mid-Triassic Periods cover an area of 500,000 Km2 in south-west China. In karst areas with spectacular landscapes characterized by magnificent tower karst and conical karst, rare surface drainage systems and prevalent subsurface drainage systems, the environment is ecologically very fragile. The rapid increase of population, over deforested and cultivated lands, worsted the ecological system, causing a higher frequency of draught, flood and various disasters, backward economic development, low living standard of the people. In order to improve the sustainability of the agriculture the experience shows that the following operations should be adopted: (1 serious control of the population increase, emigration, extra labours and improvement of the environmental education of the local inhabitants; (2 terracing of the slopes (shi jala di as to improve the cultivated land quality, to preserve the water, soil and fertiliser and ameliorate the effective utilisation of the land; (3 development of new rural energies such as the solar energy and gas energy, and expansion of the saving-fuel stoves to reduce the load of bio-energy; (4 reforestation and bounding the hills and mountains; the ecological, economic and fuel forests model has been developed in fengcong-depression areas: the tree species with high ecological, economical and energetic characteristics, should be chosen, such as the bamboo, wild grapes, Sapium rotundifolium etc.; (5 better utilisation of the ram water and karst water resource to solve the water supply problems. The karst landscape is well developed in the 500,000 km2 carbonate terrain in Yunnan, Guizhou, Guangxi, west Hunan and south Sichuan provinces in south-west China, where 100 million habitants live (Song, 1997. The large population and its high density, serious deforestation, over-cultivation and fragile ecological system make the environmental problems very serious and about 30

  17. U.S. Geological Survey Karst Interest Group Proceedings, San Antonio, Texas, May 16–18, 2017

    Science.gov (United States)

    Kuniansky, Eve L.; Spangler, Lawrence E.

    2017-05-15

    Introduction and AcknowledgmentsKarst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) and evaporites (gypsum, anhydrite, and halite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex. These factors involve biological, chemical, and physical changes that when combined with the diverse climatic regimes in which karst development has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains.The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs have resulted in the most exceptional karst areas being designated as national or state parks. Tens of thousands of similar areas in the United States have been developed into commercial caverns and known privately owned caves. Both public and private properties provide access for scientists to study the flow of groundwater in situ. Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these

  18. An examination of the factors governing the development of karst topography in the Cumberland Valley of Pennsylvania

    International Nuclear Information System (INIS)

    Ackerman, R.V.

    1993-01-01

    The landscape of the Cumberland Valley of South Central Pennsylvania is dominated by karst topography. A study was initiated to determine if the development of karst was controlled primarily by geologic structure or by lithologic differences. Existing data concerning the geographic locations of karst features, the hydrogeologic characteristics of the Cumberland Valley, and the chemistry of the eleven carbonate formations within the 518 km 2 study area were compiled. Data concerning 366 mapped sinkholes and over 9,000 additional karst features and their relations to the structural, lithological and spatial characteristics of the study area were collected and compiled into the database. Other factors contributing to karst development such as groundwater flow, soil and colluvium characteristics, and geographic distribution were considered. The data suggest that structure dominates lithology in the development of karst features within the study area. Structural features such as fractures, joints and folds, which create secondary porosity, are prerequisite for solution of the carbonate bedrock. Joint systems, fold axes, igneous intrusions, caves, springs and groundwater flow have a significant impact on the development of karst features. The presence of faults proved inconclusive. There are a greater number of karst features per unit area in areas of purer limestones (units with a lower percentage of acid insoluble residue). Lithological variations impact karst development only when structural features are present to provide secondary porosity that enhances chemical weathering. The distribution of karst features and the geologic factors governing their development and distribution should be taken into account when land-use decisions in karst terrains are made

  19. Experimental simulations of ethylene evaporites on Titan

    Science.gov (United States)

    Czaplinski, E.; Farnsworth, K.; Singh, S.; Chevrier, V.

    2017-12-01

    Titan has an abundance of lakes and seas, as identified by the Cassini spacecraft. Major components of these liquid bodies include methane (CH4) and ethane (C2H6), however minor constituents are also thought to exist (e.g. ethylene (C2H4)). As the lakes and seas evaporate, 5-μm-bright deposits, resembling evaporite deposits on Earth, are left behind in a "bathtub ring" fashion. Previous studies include models of evaporites, and observations of the 5-μm-bright regions, but the community is still lacking a complete suite of experimental evaporite studies. In this study, we experimentally investigate evaporites in order to determine their composition and how they affect infrared spectra during the evaporation process. The University of Arkansas owns a specialized chamber that simulates the surface conditions of Titan ( 90 K and 1.5 bar). Gaseous hydrocarbons are condensed within the chamber and analyzed with Fourier Transform Infrared (FTIR) Spectroscopy and band depth calculations. In this study, three types of experiments were performed: ethane/ethylene, methane/ethylene, and methane/ethane/ethylene. For these experiments, methane was the only species that readily evaporated at Titan conditions (due to its high volatility), while ethane, being the more stable solvent, did not readily evaporate. Therefore, we will present spectral results of ethylene evaporite formation within these mixtures. Our results imply that evaporite formation is strongly dependent on the composition of the solvent. The north polar lakes of Titan are predicted to be methane-rich, indicating that they may be more likely to form evaporites. Alternatively, Ontario Lacus, a south polar lake, is predominately composed of ethane, which may make it more difficult to form evaporites. As we continue to study Titan's mysterious lakes and seas, we hope to draw insights on their exact composition, conditions for evaporite formation, habitability potential, and comparing Titan to prebiotic Earth.

  20. Evaporite-hydrocarbon relationships: The case of the Laminite-reef-evaporite system in the Messinian of the Mediterranean area

    Energy Technology Data Exchange (ETDEWEB)

    Rouchy, J.M. (Museum d' Histoire Naturelle, Paris (France))

    1988-08-01

    The peripheral Messinian evaporitic basins of the Mediterranean frequently show the association between pre-evaporitic laminites, carbonate complexes (red algae, corals, and stromatolites), and evaporites which constitute a sedimentary system, including potential source rocks, reservoirs, and a cover. The pre-evaporitic laminites (mainly diatomites and carbonates) characterize two different highly productive hydrodynamic systems which follow one another: (1) coastal upwellings during lower Messinian high sea level (transgressive phase), and (2) restriction (semiclosed or land-locked basins) related to closure from the Atlantic and subsequent lower sea level (regressive phase). Preservation of the organic matter results from periodic water stratification: local O{sub 2} minimum intermediary layer and anoxic bottom conditions mainly related to hypersalinity. Extensive carbonate complexes overlie the shores and the high areas - biogenic buildups (mainly red algae and poorly diversified corals) and bioclastic accumulations locally overlapped by a stromatolitic blanket. Diagenesis and dissolution-karstification during drawdown periods (hypersaline episodes) increase the primary porosity. The evaporites constitute an efficient cover. One major property of hypersaline environments is their high primary production whose traces are identified in the Messinian series as organic-rich layers (marine or hypersaline-adapted flora and fauna) and calcareous or gypsified stromatolites. Stratified waters or reducing conditions in the pore waters favor preservation of organic matter. The evaporitic conditions greatly influence the reservoir properties, increasing porosity or destroying it by interstitial precipitation.

  1. The development of deep karst in the anticlinal aquifer structure based on the coupling of multistage flow systems

    Science.gov (United States)

    Xu, M.; Zhong, L.; Yang, Y.

    2017-12-01

    Under the background of neotectonics, the multistage underground flow system has been form due the different responses of main stream and tributaries to crust uplift. The coupling of multistage underground flow systems influences the development of karst thoroughly. At first, the research area is divided into vadose area, shunted area and exorheic area based on the development characteristics of transverse valley. Combining the controlling-drain action with topographic index and analyzing the coupling features of multistage underground flow system. And then, based on the coupling of multistage underground flow systems, the characteristics of deep karst development were verified by the lossing degree of surface water, water bursting and karst development characteristics of tunnels. The vadose area is regional water system based, whose deep karst developed well. It resulted the large water inflow of tunnels and the surface water drying up. The shunted area, except the region near the transverse valleys, is characterized by regional water system. The developed deep karst make the surface water connect with deep ground water well, Which caused the relatively large water flow of tunnels and the serious leakage of surface water. The deep karst relatively developed poor in the regions near transverse valleys which is characterized by local water system. The exorheic area is local water system based, whose the deep karst developed poor, as well as the connection among surface water and deep ground water. It has result in the poor lossing of the surface water under the tunnel construction. This study broadens the application field of groundwater flow systems theory, providing a new perspective for the study of Karst development theory. Meanwhile it provides theoretical guidance for hazard assessment and environmental negative effect in deep-buried Karst tunnel construction.

  2. Urang Cave Karst Environmental Development, as Tourism Object

    Directory of Open Access Journals (Sweden)

    Srijono Srijono

    2013-12-01

    Full Text Available Karst environment become an alternative tourist destination as well as to boost local revenues. In karst environments in Grobogan District, Central Java Province, formed Urang Cave, with an interesting endokarst phenomenon. This study aims to do zoning district Urang Cave as tourist sites. The research method is using contour maps as a base map of Urang Cave karst environment geomorphological mapping. Geomorphological data processing is using ArcView GIS 3.3 program. Land use map refers to RBI, scale 1:25.000. Geomorphological analysis refers to the Ministry of Energy and Mineral Resources No. 1456.K/20/MEM/2000, and petrography. Each development zone is analyzed its geophysical environmental element, then set scoring and value summation. For comprehensive environmental element analysis, chemical analysis of rocks, and water-soil chemistry. In reference to Minister of Energy Mineral Resource decrees No. 1456/K/20/MEM/2000, Urang Cave zoning defined into 3 (three zone, as follow: the Protected Zone, Cultivation Zone 1, and Cultivation Zone 2. Protected Zone, consists of Urang Cave tunnel/hallway with a unique spheleothem in it. This zone as a cave tracking site tourism, potential to produce karst water as a decent drinking water while maintaining hardness. Cultivation Zone 1 is spreading about 200 m in distance from outer appearance of spring around the cave hallway. In this zone mining of cave sediments may be done in the inactive form caves, without changing the state of the existing major exokarst morphology. Cultivation Zone 2, an outer zone, located farthest from the tunnel/hallway Urang Cave. Utilization of this zone as a limestone mining quarry, although only on a small scale.

  3. Reduction of risk level as one of the main challenges of development in covered karst regions

    Directory of Open Access Journals (Sweden)

    Makhnatov Stanislav A.

    2013-01-01

    Full Text Available The paper describes the experience of application of the residual karst risk concept, and presents coefficients of karst risk level reduction for planning constructional karst-protection. Practical experience of design for karstified territories of Nizhny Novgorod region demonstrates that special research of the interaction between constructions and foundations is required. Numerous accidents can serve vivid examples proving the need. I2n this situation it is important to approach the issue of safety in a proper way, taking into account probable economic, environmental and social damage. The problem can be solved by introduction of the karst risk level parameter, which permits to take into consideration constructional characteristics of objects (design philosophy, service life, as well as conditions and mechanisms of interaction between the foundation and the construction (sinkholes, local subsidence, karst-suffosion deformations, etc.. The importance of risk reduction is highlighted by current Russian Federal laws. Depending on karst risk level adequate karst-protection should be performed. For building projects, reduction of karst risk to a permissible level (conventionally equal to 1 is one of the most important research challenges of the karstified territories development, and its solution permits to plan appropriate karst protection measures.

  4. Development of a 3D GIS and its application to karst areas

    Science.gov (United States)

    Wu, Qiang; Xu, Hua; Zhou, Wanfang

    2008-05-01

    There is a growing interest in modeling and analyzing karst phenomena in three dimensions. This paper integrates geology, groundwater hydrology, geographic information system (GIS), database management system (DBMS), visualization and data mining to study karst features in Huaibei, China. The 3D geo-objects retrieved from the karst area are analyzed and mapped into different abstract levels. The spatial relationships among the objects are constructed by a dual-linker. The shapes of the 3D objects and the topological models with attributes are stored and maintained in the DBMS. Spatial analysis was then used to integrate the data in the DBMS and the 3D model to form a virtual reality (VR) to provide analytical functions such as distribution analysis, correlation query, and probability assessment. The research successfully implements 3D modeling and analyses in the karst area, and meanwhile provides an efficient tool for government policy-makers to set out restrictions on water resource development in the area.

  5. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  6. Simulation of Cavern Formation and Karst Development Using Salt

    Science.gov (United States)

    Kent, Douglas C.; Ross, Alex R.

    1975-01-01

    A salt model was developed as a teaching tool to demonstrate the development of caverns and karst topography. Salt slabs are placed in a watertight box to represent fractured limestone. Erosion resulting from water flow can be photographed in time-lapse sequence or demonstrated in the laboratory. (Author/CP)

  7. Speleogenesis in Dinaric karst area

    Science.gov (United States)

    Garasic, Mladen; Garasic, Davor

    2015-04-01

    very well-known karst region, where the first scientific researches were conducted. Abundance of all types of karst features and karstification processes active in many intervals of geological history is documented in the sequences of sedimentation (outcrops of paleokarst) from Carboniferous to present times. Animal and plant fossil and today living species support geological documentation too, which are significant tools in reconstruction of evolution of ecosystems and communities. Dinaric karst contain the most important and significant natural habitats for in-situ conservation of biological diversity of the area, and its unique animal and plant life. The Dinaric Karst is a heterogeneous geographical area made up of carbonate rocks; it represents a karst landscape typical for humid temperate regions. Its natural features are unique and have a universal value. Scientific karst terminology comes from typical natural features of the area, their genesis and several-hundred-year long study of karst and its phenomena in the Dinaric Karst. The term 'karst' is on a global leve established and accepted around the world. There are also a number of other terms originating from the Dinaric Karst that have been established in the language of science: doline, uvala, polje, ponor, kamenitza and hum among them. The Kras/Carso plateau and the Classical Karst being a part of the Dinaric Karst, are of universal cultural and historical significance. The development of the Dinaric Karst is peculiar due to a unique combination of lithology, thrust and strike-slip tectonics, exogenous processes and climate characteristics (in the past and present). The first one resulted in a combination of imbricated structures of carbonate and low permeable rock, which created hydrogeological barriers. The latter created the conditions that enabled the development of large poljes. A combination of surface and underground activity of water and its chemical processes resulted in deep karstification and a

  8. Field Investigation and Modeling Development for Hydrological and Carbon Cycles in Southwest Karst Region of China

    Science.gov (United States)

    Hu, X. B.

    2017-12-01

    It is required to understanding water cycle and carbon cycle processes for water resource management and pollution prevention and global warming influence in southwest karst region of China. Lijiang river basin is selected as our study region. Interdisciplinary field and laboratory experiments with various technologies are conducted to characterize the karst aquifers in detail. Key processes in the karst water cycle and carbon cycle are determined. Based on the MODFLOW-CFP model, new watershed flow and carbon cycle models are developed coupled subsurface and surface water flow models. Our study focus on the karst springshed in Mao village, the mechanisms coupling carbon cycle and water cycle are explored. This study provides basic theory and simulation method for water resource management and groundwater pollution prevention in China karst region.

  9. Destruction of dolines: the examples from Slovene karst

    Science.gov (United States)

    Kovacic, G.; Ravbar, N.

    2012-04-01

    Due to the absence of soil and flat agricultural land, in karst regions, the cultivation of doline bottoms and the clearing of stones on fields and meadows were traditional methods of adapting farming practices to the landscape with limited agricultural potential. In recent years, a variety of activities resulting from comprehensive economic and urban development have increased pressure on karst landscapes. In some areas the surface and the underground are increasingly threatened by industrial activities, uncontrolled settlement and spread of infrastructure, the development of tourism, and intensive agrarian land use. Unsupervised human encroachment on karst landscapes is causing the increasingly more frequent and more widespread degradation of karst relief forms. The intensive reshaping of the landscape has expanded beyond control largely as a result of technological development and mechanization. The excessive modern filling of dolines, as one of the most distinctive karst surface features, has become a major encroachment on the environment for leveling purposes. Such kind of human influence affects the shape of karst features and the appearance of the landscape as well as the intensity of karst processes such as corrosion. Many dolines are filled with general and construction waste, which threatens the existence of unique habitats and quality of groundwater and consequently water supply. This contribution presents some cases of inappropriate management of karst landscape in Slovenia and examines the national legislative framework on spatial planning in karst regions. Unfortunately, in the current legislation, the standards and conditions for the protection of karst landscape characteristics (e.g. dolines) are loose and not fully elaborated. Principally, there are no uniform mechanisms to protect specific relief forms or for the adequate protection of karst. To a large extent, the preservation of the characteristic karst landscape is left to local communities

  10. Uranium-Bearing Evaporite Mineralization Influencing Plume Persistence. Literature Review and DOE-LM Site Surveys

    International Nuclear Information System (INIS)

    2016-01-01

    This report on evaporite mineralization was completed as an Ancillary Work Plan for the Applied Studies and Technology program under the U.S. Department of Energy (DOE) Office of Legacy Management (LM). This study reviews all LM sites under Title I and Title II of the Uranium Mill Tailings Radiation Control Act (UMTRCA) and one Decontamination and Decommissioning site to provide (1) a summary of which sites have evaporite deposits, (2) any available quantitative geochemical and mineralogical analyses, and (3) references to relevant reports. In this study, 'evaporite' refers to any secondary mineral precipitate that occurs due to a loss of water through evaporative processes. This includes efflorescent salt crusts, where this term refers to a migration of dissolved constituents to the surface with a resulting salt crust, where 'salt' can refer to any secondary precipitate, regardless of constituents. The potential for the formation of evaporites at LM sites has been identified, and may have relevance to plume persistence issues. Evaporite deposits have the potential to concentrate and store contaminants at LM sites that could later be re-released. These deposits can also provide a temporary storage mechanism for carbonate, chloride, and sulfate salts along with uranium and other contaminants of concern (COCs). Identification of sites with evaporites will be used in a new technical task plan (TTP), Persistent Secondary Contaminant Sources (PeSCS), for any proposed additional sampling and analyses. This additional study is currently under development and will focus on determining if the dissolution of evaporites has the potential to hinder natural flushing strategies and impact plume persistence. This report provides an initial literature review on evaporites followed by details for each site with identified evaporites. The final summary includes a table listing of all relevant LM sites regardless of evaporite identification.

  11. Uranium-Bearing Evaporite Mineralization Influencing Plume Persistence. Literature Review and DOE-LM Site Surveys

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-01

    This report on evaporite mineralization was completed as an Ancillary Work Plan for the Applied Studies and Technology program under the U.S. Department of Energy (DOE) Office of Legacy Management (LM). This study reviews all LM sites under Title I and Title II of the Uranium Mill Tailings Radiation Control Act (UMTRCA) and one Decontamination and Decommissioning site to provide (1) a summary of which sites have evaporite deposits, (2) any available quantitative geochemical and mineralogical analyses, and (3) references to relevant reports. In this study, “evaporite” refers to any secondary mineral precipitate that occurs due to a loss of water through evaporative processes. This includes efflorescent salt crusts, where this term refers to a migration of dissolved constituents to the surface with a resulting salt crust, where “salt” can refer to any secondary precipitate, regardless of constituents. The potential for the formation of evaporites at LM sites has been identified, and may have relevance to plume persistence issues. Evaporite deposits have the potential to concentrate and store contaminants at LM sites that could later be re-released. These deposits can also provide a temporary storage mechanism for carbonate, chloride, and sulfate salts along with uranium and other contaminants of concern (COCs). Identification of sites with evaporites will be used in a new technical task plan (TTP), Persistent Secondary Contaminant Sources (PeSCS), for any proposed additional sampling and analyses. This additional study is currently under development and will focus on determining if the dissolution of evaporites has the potential to hinder natural flushing strategies and impact plume persistence. This report provides an initial literature review on evaporites followed by details for each site with identified evaporites. The final summary includes a table listing of all relevant LM sites regardless of evaporite identification.

  12. Palaeo-karst of diwa type and metallogenesis in Guangxi

    International Nuclear Information System (INIS)

    Liu Lijun; Shi Jingkun; Wang Qinghe.

    1989-01-01

    Two palaeo-karstification periods, the preliminary mobilization period and the climax-mobilization period of diwa development have been recognized. The subsurface caverns formed in these two periods were separately filled with T 3 -J 3 , K-E accumulation materials and karst Palaeokarst sedimentary rock subsequently transformed into the fossil karst-palaeo-karst sedimentary bodies which are not currently carried by modern ground water circulation. During the preliminary mobilization period of diwa development, karstification was intimately associated with Cu, Zn, Mo, Ag, Sb, Au and U mineralization, thus resulting in the formation of palaeo-karst deposit. It is supposed that ore materials were derived from the perexisting ore source stratum, bodies or mineralization. They were suffered from epigenetic weathering and leaching, were transported into ancient underground caves and were concentrated to form deposits by bacterial action. This type of the deposit possesses great potential in prospecting. The genetic model can be briefly summarized as follows: the pre-existing ore source → the diwa → superimposed palaeo-karst depression → the karst sedimentary bodies of the preliminary-mobilization period of diwa development → the anomalies of sulphophile element and radioactivity → the middle to bottom part of palaeo-karst sedimentary body along the direction of palaeo-karst → ore bodies

  13. The karst network system of the Sierra de las Nieves (Malaga, Spain). An example of a high relief Mediterranean karst

    Energy Technology Data Exchange (ETDEWEB)

    Pardo-Iguzquiza, E.; Duran, J. J.; Robledo-Ardila, P.; Luque-Espinar, J. A.; Martos-Rosillo, S.; Guardiola-Albert, C.; Pedrera, A.

    2016-07-01

    The aim of this work is the stochastic simulation of a network of karst conduits in a high relief karst system. The simulation completes the existing cave mapping provided by speleological exploration and connects the recharge area with the discharge at the karst springs. The Sierra de las Nieves karst system is a high relief Mediterranean karst that has allowed the development of a system of large conduits and caves. The system follows the typical pattern of an alpine karst system with two characteristic zones where the development of the caves is different. The first zone, with a mean altitude of 1 750 m a.s.l., the Hoyas del Pilar and Torrecilla, is the area with highest altitude where recharge takes place and where the entrance potholes to the system are located. In this zone the cave system has a development mainly along the vertical (with 1,000 m of vertical development along a few hundreds of metres of horizontal development) with large shafts and narrow and steep meanders, until the local base level is reached at 700 m a.s.l. In the second zone, the system has a quasi-horizontal development with 300 m of altitude difference for 7 km in the horizontal until the base level of the system at the Rio Grande Spring (450 m a.s.l.). The transition between both zones is dominated by the presence of sumps where the conduits have vertical ondulations. The connectivity between the entrance and the resurgence has been demonstrated, in the past, by tracer tests. The system of super caves has been made possible because of the favourable conjunction of lithological, structural, geomorphological, hydrogeological and climatic factors. Geomorphic indices are introduced to describe the three-dimensional karst networks so the known network can be completed (i.e. simulated), taking into account statistical and probabilistic criteria. The simulated system can be used for the mathematical flow simulation of the karst system. (Author)

  14. Meta-evaporite in the Carajás mineral province, northern Brazil

    Science.gov (United States)

    Riehl, Walter; Cabral, Alexandre Raphael

    2018-05-01

    Evidence for connecting evaporite-sourced high-salinity fluids with iron-oxide-copper-gold (IOCG) deposits in the Carajás mineral province has solely been based on boron-isotope compositions of tourmaline. Presence of meta-evaporitic rocks remains unrecognised. Here, we report laminated albitite, tourmalinite and banded albite-phlogopite rock, intercepted by exploratory drilling in a clastic metasedimentary sequence. These rocks represent evaporite precursors. Their location in the copper-gold prospects Açaí and Angélica, in the westernmost part of the Carajás mineral province, indicates that (i) evaporite-sourced fluids were regional and (ii) evaporite-bearing metasedimentary sequences may have been an important source of high-salinity fluids and/or sulfur for the IOCG deposits of the Carajás mineral province.

  15. Morphostructural Development of Gunungsewu Karst, Jawa Island

    Directory of Open Access Journals (Sweden)

    H. D. Tjia

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i2.157Gunungsewu Karst (also known as Sewu karst in the literature is synonymous with morphology of a carbonate terrain dominated by hills crowned by accordant-level tops that developed in a humid tropical environment by comparatively more rapid dissolution and denudation. In addition, the hills are sinoid to cone-shaped. Surface drainage is negligible compared to subsurface water flow. Abandoned channel segments and spatial arrangements of karst hills have been found to correspond with fracture patterns that are genetically associated with the regional compression direction of Jawa Island. Images derived from space platforms show many landform patterns that were neither known from ground-based nor from aerial photograph study. Landforms arranged in ring, multi-ring, spiral, polygonal, and long linear to serpentine patterns are common beside the expected depressions of dolines, poljes, and uvalas. The orientations of the long linear ridges appear to change systematically from those near the coast to those located inland. These linear ridges are interpreted as depositional fronts, most likely representing breaker zones. The youngest depositional ridge fronts, located nearest to the present shoreline, are parallel to the geological strike of Jawa Island. Toward the island’s interior, linear depositional fronts deviate in orientation by as much as 40o. This is now interpreted to have resulted from counterclockwise rotation of the Gunungsewu microplate since the late Middle Miocene. Similar CCW rotations are indicated by the paleomagnetic orientations of igneous rocks located farther east in the southern range of the island. Active tectonics is expressed in stage-wise net uplift of Gunungsewu whereas regional tilting appears negligible. Stacked and often paired river terraces (thus suggesting land uplift have been used to relatively date paleoarcheological finds. Very recent uplift on the coast show up in lazy-V limestone

  16. Danburite in evaporites of the Paradox basin, Utah.

    Science.gov (United States)

    Raup, O.B.; Madsen, B.M.

    1986-01-01

    Danburite (CaB2Si2O8) has been found as nodules in Pennsylvanian age marine evaporites. The occurrence of danburite and its relation to the host rock in the Paradox basin evaporites indicates that it most likely formed by diagenetic reaction of boron-rich, high-salinity brines with constituents in the anhydrite host rock.-from Authors

  17. Gypsum karst in Italy: a review

    Science.gov (United States)

    De Waele, Jo; Chiarini, Veronica; Columbu, Andrea; D'Angeli, Ilenia M.; Madonia, Giuliana; Parise, Mario; Piccini, Leonardo; Vattano, Marco; Vigna, Bartolomeo; Zini, Luca; Forti, Paolo

    2016-04-01

    Although outcropping only rarely in Italy, gypsum karst has been described in detail since the early XXth century (Marinelli, 1917). Gypsum caves are now known from almost all Italian regions (Madonia & Forti, 2003), but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche regions), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum quarries in Piedmont (Vigna et al., 2010). During the late 80s and 90s several multidisciplinary studies have been carried out in many gypsum areas. All this work converged into a comprehensive overview in 2003 (Madonia & Forti, 2003). Further detailed studies focused on the gypsum areas of Emilia Romagna (Chiesi et al., 2010; Forti & Lucci, 2010; Demaria et al., 2012; De Waele & Pasini, 2013; Ercolani et al., 2013; Columbu et al., 2015; Lucci & Piastra, 2015; Tedeschi et al., 2015) and of Sicily (Madonia & Vattano, 2011). Sinkholes related to Permo-Triassic gypsum have been studied in Friuli Venezia Giulia (Zini et al., 2015). This presentation will review the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results. References Chiesi M., et al. (2010) - Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy). Hydrogeology Journal, 18, pp. 1111-1124. Columbu A. et al. (2015) - Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region. Geology, 43(6), 539-542. Demaria D. et al. (Eds.) (2012), Le Grotte Bolognesi, GSB-USB, 431 p. De Waele J., Pasini G. (2013) - Intra-messinian gypsum palaeokarst in the northern Apennines and its palaeogeographic implications. Terra Nova 25, pp. 199-205. Ercolani M., et al. (Eds.) (2013), I Gessi e la Cave i Monte Tondo. Studio multidisciplinare di un'area carsica nella Vena del Gesso Romagnola. Memorie Ist. It. Spel. II(26), 559 p

  18. Development of a process-oriented vulnerability concept for water travel time in karst aquifers-case study of Tanour and Rasoun springs catchment area.

    Science.gov (United States)

    Hamdan, Ibraheem; Sauter, Martin; Ptak, Thomas; Wiegand, Bettina; Margane, Armin; Toll, Mathias

    2017-04-01

    Key words: Karst aquifer, water travel time, vulnerability assessment, Jordan. The understanding of the groundwater pathways and movement through karst aquifers, and the karst aquifer response to precipitation events especially in the arid to semi-arid areas is fundamental to evaluate pollution risks from point and non-point sources. In spite of the great importance of the karst aquifer for drinking purposes, karst aquifers are highly sensitive to contamination events due to the fast connections between the land-surface and the groundwater (through the karst features) which is makes groundwater quality issues within karst systems very complicated. Within this study, different methods and approaches were developed and applied in order to characterise the karst aquifer system of the Tanour and Rasoun springs (NW-Jordan) and the flow dynamics within the aquifer, and to develop a process-oriented method for vulnerability assessment based on the monitoring of different multi-spatially variable parameters of water travel time in karst aquifer. In general, this study aims to achieve two main objectives: 1. Characterization of the karst aquifer system and flow dynamics. 2. Development of a process-oriented method for vulnerability assessment based on spatially variable parameters of travel time. In order to achieve these aims, different approaches and methods were applied starting from the understanding of the geological and hydrogeological characteristics of the karst aquifer and its vulnerability against pollutants, to using different methods, procedures and monitored parameters in order to determine the water travel time within the aquifer and investigate its response to precipitation event and, finally, with the study of the aquifer response to pollution events. The integrated breakthrough signal obtained from the applied methods and procedures including the using of stable isotopes of oxygen and hydrogen, the monitoring of multi qualitative and quantitative parameters

  19. Recent Trends in Karst Geomorphology.

    Science.gov (United States)

    Palmer, Arthur N.

    1984-01-01

    Recent trends related to the karst processes and the evolution of karst landscapes are discussed. The hydrochemical processes responsible for the origin of karst are expanded on to illustrate the present scope of karst studies. These geomorphological studies are combined with concepts and techniques from hydraulics, chemistry, and mathematics. (JN)

  20. The sequence stratigraphy, sedimentology, and economic importance of evaporite carbonate transitions: a review

    Science.gov (United States)

    Sarg, J. F.

    2001-04-01

    World-class hydrocarbon accumulations occur in many ancient evaporite-related basins. Seals and traps of such accumulations are, in many cases, controlled by the stratigraphic distribution of carbonate-evaporite facies transitions. Evaporites may occur in each of the systems tracts within depositional sequences. Thick evaporite successions are best developed during sea level lowstands due to evaporative drawdown. Type 1 lowstand evaporite systems are characterized by thick wedges that fill basin centers, and onlap basin margins. Very thick successions (i.e. saline giants) represent 2nd-order supersequence set (20-50 m.y.) lowstand systems that cap basin fills, and provide the ultimate top seals for the hydrocarbons contained within such basins. Where slope carbonate buildups occur, lowstand evaporites that onlap and overlap these buildups show a lateral facies mosaic directly related to the paleo-relief of the buildups. This facies mosaic, as exemplified in the Silurian of the Michigan basin, ranges from nodular mosaic anhydrite of supratidal sabkha origin deposited over the crests of the buildups, to downslope subaqueous facies of bedded massive/mosaic anhydrite and allochthonous dolomite-anhydrite breccias. Facies transitions near the updip onlap edges of evaporite wedges can provide lateral seals to hydrocarbons. Porous dolomites at the updip edges of lowstand evaporites will trap hydrocarbons where they onlap nonporous platform slope deposits. The Desert Creek Member of the Paradox Formation illustrates this transition. On the margins of the giant Aneth oil field in southeastern Utah, separate downdip oil pools have accumulated where dolomudstones and dolowackestones with microcrystalline porosity onlap the underlying highstand platform slope. Where lowstand carbonate units exist in arid basins, the updip facies change from carbonates to evaporite-rich facies can also provide traps for hydrocarbons. The change from porous dolomites composed of high

  1. COMPOSITIONAL SIMILARITIES AND DISTINCTIONS BETWEEN TITAN’S EVAPORITIC TERRAINS

    Energy Technology Data Exchange (ETDEWEB)

    MacKenzie, S. M.; Barnes, Jason W., E-mail: mack3108@vandals.uidaho.edu [Department of Physics, University of Idaho, Moscow, ID 83844-0903 (United States)

    2016-04-10

    We document the similarities in composition between the equatorial basins Tui Regio, Hotei Regio, and other 5-μm-bright materials, notably the north polar evaporites, by investigating the presence and extent of an absorption feature at 4.92 μm. In most observations, Woytchugga Lacuna, Ontario Lacus, MacKay Lacus, deposits near Fensal, some of the lakes and dry lake beds south of Ligeia, and the southern shores of Kraken Mare share the absorption feature at 4.92 μm observed in the spectra of Tui and Hotei. Besides Woytchugga and at Fensal, these 5-μm-bright deposits are geomorphologically substantiated evaporites. Thus, the similarity in composition strengthens the hypothesis that Tui and Hotei once contained liquid. Other evaporite deposits, however, do not show the 4.92 μm absorption, notably Muggel Lacus and the shores of Ligeia Mare at the north pole. This difference in composition suggests that there is more than one kind of soluble material in Titan’s lakes that can create evaporite and/or that the surface properties at the Visual and Infrared Mapping Spectrometer wavelength scale are not uniform between the different deposits (crystal size, abundance, etc.). Our results indicate that the surface structure, composition, and formation history of Titan’s evaporites may be at least as dynamic and complex as their Earth counterparts.

  2. Petrographic study of evaporite deformation near the Waste Isolation Pilot Plant (WIPP)

    International Nuclear Information System (INIS)

    Borns, D.J.

    1983-06-01

    The Delaware Basin of southeastern New Mexico contains about 1000 m of layered evaporites. Areas in the northern Delaware Basin, bordering the Capitan reef, have anomalous seismic reflection characteristics, such as loss in reflector continuity. Core from holes within this zone exhibits complex mesoscopic folds and extension structures. On a larger scale, anticlines and synclines are indicated by structure contours based on boreholes. The deformation is probably gravity-driven. Such a process is initiated by basin tilting during either a Mesozoic or Cenozoic period of uplift. Small-scale structures suggest that deformation was episodic with an early, syndepositional stage of isoclinal folding. Later, open-to-tight asymmetric folding is more penetrative and exhibits a sense of asymmetry opposite to that of the earlier isoclinal folding. The younger folds are associated with development of zonal crenulation cleavage and microboundinage of more competent carbonate layers. At the same time, halite beds developed dimensional fabrics and convolute folds in anhydrite stringers. Late-stage, near-vertical fractures formed in competent anhydrite layers. Microscopic textures exhibit rotated anhydrite porphyroblasts, stress shadow growth, and microboundinage. Except during late-stage deformation, anhydrite and halite recrystallized synkinematically. Drastic strength reduction in anhydrites through dynamic recrystallization occurs experimentally near 200 0 C. However, evaporites of the WIPP site never experienced temperatures > 40 0 C. Microscopic fabrics and P, T history of the evaporites suggest that pressure solution was the active mechanism during deformation of evaporites at the WIPP site

  3. Karst risk assessment for engineering in Nizhny Novgorod region, Russia

    Directory of Open Access Journals (Sweden)

    Tolmachev Vladimir

    2013-01-01

    Full Text Available Federal Standards of the Russian include the requirement of mandatory assessment of the risks induced by natural processes in order to make sure their values do not exceed acceptable limits. To meet the requirement a number of karst risk assessment methods have been developed for the regions of the country where the most significant hazard is presented by karst sinkholes. For this particular application karst risk is understood as specific probability of sinkhole development on a unit area per a unit time span with account of probable economic, social and environmental components of damage. The probability of sinkhole development is evaluated by specialists in engineering karstology and designers. They make use of the acceptable data on the environmental conditions and apply stochastic laws of sinkhole development in time and space, alongside with focusing on all other relevant specificity of the building or facility to be built. Acceptable limits of karst risks should be specified by a multidisciplinary team including designers, lawyers, economists, insurers, environmentalists, engineering karstologists and other specialists on the basis of their expert knowledge. It has been demonstrated that a ratio between predicted and acceptable karst risk values can serve a practically meaningful karst risk level indicator for the purposes of building on karst. This ratio can be used with a rather high degree of objectiveness to develop a programme of antikarst activities during both facilities construction and operation.

  4. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    OpenAIRE

    Zexuan Xu; Seth Willis Bassett; Bill Hu; Scott Barrett Dyer

    2016-01-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and travel...

  5. Climatic classification of the Karst

    International Nuclear Information System (INIS)

    Eslava Ramirez Jesus Antonio; Bahamon Ayala, Sandra Marcela; Lopez Romero Maria Ines

    2000-01-01

    Climate is one the main factors in forming or modifying Karsts, or its resulting forms. The determining climatic elements of Karst characteristics are humidity, air circulation and temperature. Many Karstic processes show characteristics corresponding to a given climate sequence. In the present article we discuss the relation between climate and Karst as well as a climate classification based on the structure of the Karsts

  6. Tracer techniques in karst hydrogeology. Application to the location of karst aquifers

    International Nuclear Information System (INIS)

    Mangin, A.; Molinari, J.

    1976-01-01

    From the recent progress in karst aquifer simulation techniques and the improved knowledge of tracers, the old-established tracer technique has become an invaluable instrument for hydrogeological survey work. Typical information obtainable includes karst system boundaries features and location of hydrodynamic discontinuities, flow variation in both space and time. Tracer methods are a basic requirement for investigation of karst groundwater supplies and determining protection zones for water supply points [fr

  7. Spatial Distribution of Nitrogen on Grazed Karst Landscapes

    Directory of Open Access Journals (Sweden)

    Douglas G. Boyer

    2001-01-01

    Full Text Available The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian region. Karst areas comprise about 18% of the region’s land area. An estimated one-third of the region’s farms, cattle, and agricultural market value are located on karst terrain. Mean nitrate concentrations in several karst springs in southeastern West Virginia exhibit a strong linear relationship with the percentage of agriculture land cover. Development of best management practices for efficient nitrogen (N use and reduction of outflow of N to water from karst areas requires knowledge about N dynamics on those landscapes. Water extractable NO3-N and NH4-N were measured along transects at four soil depths in two grazed sinkholes and one wooded sinkhole. Distribution of soil NO3-N and NH4-N were related to frequency of animal presence and to topographic and hydrologic redistribution of soil and fecal matter in the grazed sinkholes. Karst pastures are characterized by under drainage and funneling of water and contaminants to the shallow aquifer. Control of NO3-N leaching from karst pasture may depend on management strategies that change livestock grazing behavior in sinkholes and reduce the opportunity for water and contaminants to quickly reach sinkhole drains.

  8. U.S. Geological Survey Karst Interest Group Proceedings, Carlsbad, New Mexico, April 29-May 2, 2014

    Science.gov (United States)

    Kuniansky, Eve L.; Spangler, Lawrence E.; Kuniansky, Eve L.; Spangler, Lawrence E.

    2014-01-01

    Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex, and involve biological, chemical, and physical changes. These factors, combined with the diverse climatic regimes under which karst development in these rocks has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains.The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs has resulted in the most exceptional karst areas of the United States being designated as national or state parks; commercial caverns and known privately owned caves number in the tens of thousands. Both public and private properties provide access for scientists to study the flow of groundwater in situ. Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal, state, and local agencies have a

  9. Karst of the Mid-Atlantic region in Maryland, West Virginia, and Virginia

    Science.gov (United States)

    Doctor, Daniel H.; Weary, David J.; Brezinski, David K.; Orndorff, Randall C.; Spangler, Lawrence E.; Brezinski, David K.; Halka, Jeffrey; Ortt, Richard A.

    2015-01-01

    The Mid-Atlantic region hosts some of the most mature karst landscapes in North America, developed in highly deformed rocks within the Piedmont and Valley and Ridge physiographic provinces. This guide describes a three-day excursion to examine karst development in various carbonate rocks by following Interstate 70 west from Baltimore across the eastern Piedmont, across the Frederick Valley, and into the Great Valley proper. The localities were chosen in order to examine the structural and lithological controls on karst feature development in marble, limestone, and dolostone rocks with an eye toward the implications for ancient landscape evolution, as well as for modern subsidence hazards. A number of caves will be visited, including two commercial caverns that reveal strikingly different histories of speleogenesis. Links between karst landscape development, hydrologic dynamics, and water resource sustainability will also be emphasized through visits to locally important springs. Recent work on quantitative dye tracing, spring water geochemistry, and groundwater modeling reveal the interaction between shallow and deep circulation of groundwater that has given rise to the modern karst landscape. Geologic and karst feature mapping conducted with the benefit of lidar data help reveal the strong bedrock structural controls on karst feature development, and illustrate the utility of geologic maps for assessment of sinkhole susceptibility.

  10. Dissolution of Kansas evaporites: the radioactive waste disposal problem

    International Nuclear Information System (INIS)

    Smith, B.J.

    1977-01-01

    The radioactive waste repository at Lyons, Kansas, focused attention on the problem of evaporite dissolution. More study is needed in the determination of the mechanisms responsible for deterioration. Also, recent water-use policies have been questioned with the need pointed out for increased effectiveness in planning. Good water planning has to take into account the role of evaporite dissolution in water quality. 23 references

  11. Geological constraints on cave development in the plateau-gorge karst of South China (Wulong, Chongqing)

    Science.gov (United States)

    Szczygieł, Jacek; Golicz, Mateusz; Hercman, Helena; Lynch, Erin

    2018-03-01

    The Houping Tiankeng cluster is a part of the South China Karst UNESCO World Natural Heritage Site. Within the distinctive Wulong plateau-gorge karst, > 200 km of cave passages have been documented to date. This paper focuses on detailed tectonic and morphological research on the Luo Shui Kong cave, enriched with U-series dating of speleothems and complemented by morphometric analysis of the San Wang Dong and Er Wang Dong caves. All of these caves exhibit three regional levels of cave development: 1) 1040-1020 m a.s.l.; 2) 900-840 m a.s.l.; and 3) 740-660 m a.s.l. The Houping Tiankeng area is a carbonate rock sequence several hundred meters thick, overlain by the less soluble Lower Ordovician strata, limiting recharge points to faults exposing underlying easily soluble formations. This leads to the domination of concentrated, high-volume inflow and thus results in caves of large volume in the plateau-gorge karst. Shafts connecting the surface with cave passages located underneath formed along faults, changing the hydrogeological pattern through karst water capture and remodeling of existing conduits, albeit mainly by increasing their overall dimensions rather than by deepening them. The most favorable structures for cave-level development are two sets of joints conjugated with gently inclined bedding. Since these joints are characterized by a small vertical extent, downward development is limited. Hence, most of the passages are wide but not deep canyons and typical of a water-table cave pattern. Places where the fault plane is eroded from the surface and where, at the same time, an underneath cave chamber ceiling expands upwards are particularly predisposed to the formation of a tiankeng.

  12. Verification of the karst flow model under laboratory controlled conditions

    Science.gov (United States)

    Gotovac, Hrvoje; Andric, Ivo; Malenica, Luka; Srzic, Veljko

    2016-04-01

    Karst aquifers are very important groundwater resources around the world as well as in coastal part of Croatia. They consist of extremely complex structure defining by slow and laminar porous medium and small fissures and usually fast turbulent conduits/karst channels. Except simple lumped hydrological models that ignore high karst heterogeneity, full hydraulic (distributive) models have been developed exclusively by conventional finite element and finite volume elements considering complete karst heterogeneity structure that improves our understanding of complex processes in karst. Groundwater flow modeling in complex karst aquifers are faced by many difficulties such as a lack of heterogeneity knowledge (especially conduits), resolution of different spatial/temporal scales, connectivity between matrix and conduits, setting of appropriate boundary conditions and many others. Particular problem of karst flow modeling is verification of distributive models under real aquifer conditions due to lack of above-mentioned information. Therefore, we will show here possibility to verify karst flow models under the laboratory controlled conditions. Special 3-D karst flow model (5.6*2.6*2 m) consists of concrete construction, rainfall platform, 74 piezometers, 2 reservoirs and other supply equipment. Model is filled by fine sand (3-D porous matrix) and drainage plastic pipes (1-D conduits). This model enables knowledge of full heterogeneity structure including position of different sand layers as well as conduits location and geometry. Moreover, we know geometry of conduits perforation that enable analysis of interaction between matrix and conduits. In addition, pressure and precipitation distribution and discharge flow rates from both phases can be measured very accurately. These possibilities are not present in real sites what this model makes much more useful for karst flow modeling. Many experiments were performed under different controlled conditions such as different

  13. Karst Feature Inventory Points

    Data.gov (United States)

    Minnesota Department of Natural Resources — Southeastern Minnesota is part of the Upper Mississippi Valley Karst (Hedges and Alexander, 1985) that includes southwestern Wisconsin and northeastern Iowa. Karst...

  14. Geological-geophysical techniques applied to urban planning in karst hazardous areas. Case study of Zaragoza, NE Spain

    Science.gov (United States)

    Pueyo Anchuela, O.; Soriano, A.; Casas Sainz, A.; Pocoví Juan, A.

    2009-12-01

    Industrial and urban growth must deal in some settings with geological hazards. In the last 50 years, the city of Zaragoza (NE Spain) has developed an increase of its urbanized area in a progression several orders higher than expected from its population increase. This fast growth has affected several areas around the city that were not usually used for construction. Maps of the Zaragoza city area at the end of the XIXth century and beginning of the XXth reveal the presence of karst hazards in several zones that can be observed in more modern data, as aerial photographs taken during a period ranging from 1927 to present. The urban and industrial development has covered many of these hazardous zones, even though potential risks were known. The origins of the karst problems are related to the solution of evaporites (mainly gypsum, glauberite and halite) that represent the Miocene substratum of the Zaragoza area underlying the Quaternary terraces and pediments related to the Ebro River and its tributaries. Historical data show the persistence of subsidence foci during long periods of time while in recent urbanized areas this stability is not shared, observing the increase of activity and/or radius affection in short periods of time after building over. These problems can be related to two factors: i) urban development over hazardous areas can increase the karst activity and ii) the affection radius is not properly established with the commonly applied methods. One way to develop these detailed maps can be related to the geophysical approach. The applied geophysical routine, dependent on the characteristics of the surveyed area, is based on potential geophysical techniques (magnetometry and gravimetry) and others related to the application of induced fields (EM and GPR). The obtained results can be related to more straightforward criteria as the detection of cavities in the subsoil and indirect indicators related to the long-term activity of the subsidence areas

  15. Conduit enlargement in an eogenetic karst aquifer

    Science.gov (United States)

    Moore, Paul J.; Martin, Jonathan B.; Screaton, Elizabeth J.; Neuhoff, Philip S.

    2010-11-01

    SummaryMost concepts of conduit development have focused on telogenetic karst aquifers, where low matrix permeability focuses flow and dissolution along joints, fractures, and bedding planes. However, conduits also exist in eogenetic karst aquifers, despite high matrix permeability which accounts for a significant component of flow. This study investigates dissolution within a 6-km long conduit system in the eogenetic Upper Floridan aquifer of north-central Florida that begins with a continuous source of allogenic recharge at the Santa Fe River Sink and discharges from a first-magnitude spring at the Santa Fe River Rise. Three sources of water to the conduit include the allogenic recharge, diffuse recharge through epikarst, and mineralized water upwelling from depth. Results of sampling and inverse modeling using PHREEQC suggest that dissolution within the conduit is episodic, occurring only during 30% of 16 sampling times between March 2003 and April 2007. During low flow conditions, carbonate saturated water flows from the matrix to the conduit, restricting contact between undersaturated allogenic water with the conduit wall. When gradients reverse during high flow conditions, undersaturated allogenic recharge enters the matrix. During these limited periods, estimates of dissolution within the conduit suggest wall retreat averages about 4 × 10 -6 m/day, in agreement with upper estimates of maximum wall retreat for telogenetic karst. Because dissolution is episodic, time-averaged dissolution rates in the sink-rise system results in a wall retreat rate of about 7 × 10 -7 m/day, which is at the lower end of wall retreat for telogenetic karst. Because of the high permeability matrix, conduits in eogenetic karst thus enlarge not just at the walls of fractures or pre-existing conduits such as those in telogenetic karst, but also may produce a friable halo surrounding the conduits that may be removed by additional mechanical processes. These observations stress the

  16. A model of karst systems of the Usturt plateau (Middle Asia)

    International Nuclear Information System (INIS)

    Victorov, A. S.

    2016-01-01

    The issues relating to the structure and development of desert karst is currently one of the least studied problems. The goal of the research efforts presented in this paper was to create a model of karst systems in the Usturt Plateau and, primarily, of the systems formed by the prevailing numerous surface karst landforms. The model is based on the following main assumptions: the process of emergence of the karst phenomena is probabilistic and occurs independently at non-intersecting sites; the probability of emergence of one depression at a reference site depends only on its area. The increase of the dimensions of a karst landform is a random process that occurs independently of other karst landforms, its speed is governed by random factors, and it is directly proportionate to the existing dimensions of the landform. The model does not assume constancy of climatic characteristics. The testing was conducted at several reference sites of the Usturt Plateau. The research allowed us to reach the following conclusions: the karst depressions of the Usturt Plateau, which are the typical forms of desert karst, are governed by the Poisson distribution of their centres and by the lognormal distribution of their dimensions, similar to the karst depressions in a humid climate. The results may be used in assessments of karst hazard for linear and areal structures, as well as for small-dimensional structures. (Author)

  17. Gypsum karst in Great Britain

    Directory of Open Access Journals (Sweden)

    Cooper A.H.

    1996-01-01

    Full Text Available In Great Britain the most spectacular gypsum karst development is in the Zechstein gypsum (late Permian mainly in north-eastern England. The Midlands of England also has some karst developed in the Triassic gypsum in the vicinity of Nottingham. Along the north-east coast, south of Sunderland, well-developed palaeokarst, with magnificent breccia pipes, was produced by dissolution of Permian gypsum. In north-west England a small gypsum cave system of phreatic origin has been surveyed and recorded. A large actively evolving phreatic gypsum cave system has been postulated beneath the Ripon area on the basis of studies of subsidence and boreholes. The rate of gypsum dissolution here, and the associated collapse lead to difficult civil engineering and construction conditions, which can also be aggravated by water abstraction.

  18. Deposition of Boron in Possible Evaporite Deposits in Gale Crate

    Science.gov (United States)

    Gasda, P. J.; Peets, E.; Lamm, S. N.; Rapin, W.; Lanza, N.; Frydenvang, J.; Clark, B. C.; Herkenhoff, K. E.; Bridges, J.; Schwenzer, S. P.; Haldeman, E. B.; Wiens, R. C.; Maurice, S.; Clegg, S. M.; Delapp, D.; Sanford, V.; Bodine, M. R.; McInroy, R.

    2017-12-01

    Boron has been previously detected in Gale crater using the ChemCam instrument on board the NASA Curiosity rover within calcium sulfate fracture fill hosted by lacustrine mudstone and eolian sandstone units. Recent results show that up to 300 ppm B is present in the upper sections of the lacustrine unit. Boron has been detected in both the groundwater-emplaced calcium sulfate fracture fill materials and bedding-parallel calcium sulfate layers. The widespread bedding-parallel calcium sulfate layers within the upper strata of the lacustrine bedrock that Curiosity has encountered recently could be interpreted as primary evaporite deposits. We have two hypotheses for the history of boron in Gale crater. In both hypotheses, borates were first deposited as lake water evaporated, depositing primary evaporates that were later re-dissolved by groundwater, which redistributed the boron into secondary evaporitic calcium sulfate fracture fill deposits. In the first scenario, Gale crater may have undergone a period of perennial lake formation during a drier period of martian history, depositing layers of evaporitic minerals (including borates) among lacustrine mudstone layers. In the second scenario, lake margins could have become periodically exposed during cyclic drops in lake level and subsequently desiccated. Evaporites were deposited and desiccation features were formed in lowstand deposits. Either hypothetical scenario of evaporite deposition would promote prebiotic chemical reactions via wet-dry cycles. Boron may be an important prebiotic element, and as such, its presence in ancient martian surface and groundwater provides evidence that important prebiotic chemical reactions could occur on Mars if organics were present. The presence of boron in ancient Gale crater groundwater also provides additional evidence that a habitable environment existed in the martian subsurface well after the expected disappearance of liquid water on the surface of Mars. We will report on the

  19. STUDY ON KARST INFORMATION IDENTIFICATION OF QIANDONGNAN PREFECTURE BASED ON RS AND GIS TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    M. Yao

    2018-04-01

    Full Text Available Karst area is a pure natural resource base, at the same time, due to the special geological environment; there are droughts and floods alternating with frequent karst collapse, rocky desertification and other resource and environment problems, which seriously restrict the sustainable economic and social development in karst areas. Therefore, this paper identifies and studies the karst, and clarifies the distribution of karst. Provide basic data for the rational development of resources in the karst region and the governance of desertification. Due to the uniqueness of the karst landscape, it can’t be directly recognized and extracted by computer in remote sensing images. Therefore, this paper uses the idea of “RS + DEM” to solve the above problems. this article is based on Landsat-5 TM imagery in 2010 and DEM data, proposes the methods to identify karst information research what is use of slope vector diagram, vegetation distribution map, distribution map of karst rocky desertification and other auxiliary data in combination with the signs for human-computer interaction interpretation, identification and extraction of peak forest, peaks cluster and isolated peaks, and further extraction of karst depression. Experiments show that this method achieves the “RS + DEM” mode through the reasonable combination of remote sensing images and DEM data. It not only effectively extracts karst areas covered with vegetation, but also quickly and accurately locks down the karst area and greatly improves the efficiency and precision of visual interpretation. The accurate interpretation rate of karst information in study area in this paper is 86.73 %.

  20. Study on Karst Information Identification of Qiandongnan Prefecture Based on RS and GIS Technology

    Science.gov (United States)

    Yao, M.; Zhou, G.; Wang, W.; Wu, Z.; Huang, Y.; Huang, X.

    2018-04-01

    Karst area is a pure natural resource base, at the same time, due to the special geological environment; there are droughts and floods alternating with frequent karst collapse, rocky desertification and other resource and environment problems, which seriously restrict the sustainable economic and social development in karst areas. Therefore, this paper identifies and studies the karst, and clarifies the distribution of karst. Provide basic data for the rational development of resources in the karst region and the governance of desertification. Due to the uniqueness of the karst landscape, it can't be directly recognized and extracted by computer in remote sensing images. Therefore, this paper uses the idea of "RS + DEM" to solve the above problems. this article is based on Landsat-5 TM imagery in 2010 and DEM data, proposes the methods to identify karst information research what is use of slope vector diagram, vegetation distribution map, distribution map of karst rocky desertification and other auxiliary data in combination with the signs for human-computer interaction interpretation, identification and extraction of peak forest, peaks cluster and isolated peaks, and further extraction of karst depression. Experiments show that this method achieves the "RS + DEM" mode through the reasonable combination of remote sensing images and DEM data. It not only effectively extracts karst areas covered with vegetation, but also quickly and accurately locks down the karst area and greatly improves the efficiency and precision of visual interpretation. The accurate interpretation rate of karst information in study area in this paper is 86.73 %.

  1. Fractal Prediction of Grouting Volume for Treating Karst Caverns along a Shield Tunneling Alignment

    Directory of Open Access Journals (Sweden)

    Wen-Chieh Cheng

    2017-06-01

    Full Text Available Karst geology is common in China, and buried karst formations are widely distributed in Guangdong province. In the process of shield tunneling, the abundant water resources present in karst caverns could lead to the potential for high water ingress, and a subsequent in situ stress change-induced stratum collapse. The development and distribution of karst caverns should therefore be identified and investigated prior to shield tunnel construction. Grouting is an efficient measure to stabilize karst caverns. The total volume of karst caverns along the shield tunneling alignment, and its relationship with the required volume of grouts, should be evaluated in the preliminary design phase. Conventionally, the total volume of karst caverns is empirically estimated based on limited geological drilling hole data; however, accurate results are rarely obtained. This study investigates the hydrogeology and engineering geology of Guangzhou, the capital of Guangdong province, and determines the fractal characteristics of the karst caverns along the tunnel section of Guangzhou metro line no. 9. The karst grouting coefficients (VR were found to vary from 0.11 in the case of inadequate drilling holes to 1.1 in the case where adequate drilling holes are provided. A grouting design guideline was furthermore developed in this study for future projects in karst areas.

  2. Origin and chemical composition of evaporite deposits

    Science.gov (United States)

    Moore, George William

    1960-01-01

    A comparative study of marine evaporite deposits forming at the present time along the pacific coast of central Mexico and evaporite formations of Permian age in West Texas Basin was made in order to determine if the modern sediments provide a basis for understanding environmental conditions that existed during deposition of the older deposits. The field work was supplemented by investigations of artificial evaporite minerals precipitated in the laboratory and by study of the chemical composition of halite rock of different geologic ages. The environment of deposition of contemporaneous marine salt deposits in Mexico is acidic, is strongly reducing a few centimeters below the surface, and teems with microscopic life. Deposition of salt, unlike that of many other sediments, is not wholly a constructional phenomenon. Permanent deposits result only if a favorable balance exists between deposition in the dry season and dissolution in the wet season. Evaporite formations chosen for special study in the West Texas Basin are, in ascending order, the Castile, Salado, and Rustler formations, which have a combined thickness of 1200 meters. The Castile formation is largely composed of gypsum rock, the Salado, halite rock, and the Rustler, quartz and carbonate sandstone. The lower part of the Castile formation is bituminous and contains limestone laminae. The Castile and Rustler formations thicken to the south at the expense of salt of the intervening Salado formation. The clastic rocks of the Rustler formation are interpreted as the deposits of a series of barrier islands north of which halite rock of the Salado was deposited. The salt is believed to have formed in shallow water of uniform density that was mixed by the wind. Where water depth exceeded the depth of the wind mixing, density stratification developed, and gypsum was deposited. Dense water of high salinity below the density discontinuity was overlain by less dense, more normally saline water which was derived from

  3. U.S. Geological Survey Karst Interest Group Proceedings, Bowling Green, Kentucky, May 27-29, 2008

    Science.gov (United States)

    Kuniansky, Eve L.

    2008-01-01

    *INTRODUCTION AND ACKNOWLEDGMENTS* Karst aquifer systems are present throughout parts of the United States and some of its territories. The complex depositional environments that form carbonate rocks combined with post-depositional tectonic events and the diverse climatic regimes under which these rocks were formed result in unique hydrologic systems. The dissolution of calcium carbonate and the subsequent development of distinct and beautiful landscapes, caverns, and springs have resulted in some karst areas of the United States being designated as national or state parks and commercial caverns. Karst aquifers and landscapes that form in tropical areas, such as the north coast of Puerto Rico, differ greatly from karst areas in more arid climates, such as central Texas or western South Dakota. Many of these public and private lands contain unique flora and fauna associated with the hydrologic systems in these karst areas. As a result, multiple Federal, State, and local agencies have an interest in the study of karst terrains. Carbonate sediments and rocks (limestone and dolomite) are composed of greater than 50 percent carbonate minerals and the predominant carbonate mineral is calcium carbonate or limestone (CaCO3). Unlike terrigenous clastic sedimentation, the depositional processes that produce carbonate rocks are complex, involving both biological and physical processes. These depositional processes impact greatly the development of permeability of the sediments. Carbonate minerals readily dissolve or precipitate depending on the chemistry of the water flowing through the rock, thus the study of both marine and meteoric diagenesis of carbonate sediments is multidisciplinary. Even with a better understanding of the depositional environment and subsequent diagenesis, the dual porosity nature of karst aquifers presents challenges to scientists attempting to study ground-water flow and contaminant transport. Many of the major springs and aquifers in the United

  4. Concepts of karst development in relation to interpretation of surface runoff

    Science.gov (United States)

    LeGrand, H.E.; Stringfield, V.T.

    1973-01-01

    Some unusual characteristics of streamflow occur in regions underlain by carbonate rocks. The streamflow characteristics are related to processes of karstification, these processes being dependent on circulation of subsurface water and solution of the rock to form characteristic topography and underground cavern systems.  Very highly cavernous and permeable unsaturated zones tend to keep the water table depressed below land surface in many karst regions, a condition that leads to a low density of perennial streams. The uneven distribution of permeability beneath surface karst streams causes them to lose or gain water, depending on the position of the water table with reference to stream level. The conventional techniques of interpolation and extrapolation that have been reasonably successful in approximating streamflow of ungaged sites in nonkarstic regions have only limited use in karst regions. An understanding of principles of karstification and an understanding of the hydrogeologic framework of a carbonate terrane provide a useful basis for evaluating the streamflow characteristics.

  5. Imaging of karsts on buried carbonate platform in Central Luconia Province, Malaysia

    Science.gov (United States)

    Nur Fathiyah Jamaludin, Siti; Mubin, Mukhriz; Latiff, Abdul Halim Abdul

    2017-10-01

    Imaging of carbonate rocks in the subsurface through seismic method is always challenging due to its heterogeneity and fast velocity compared to the other rock types. Existence of karsts features on the carbonate rocks make it more complicated to interpret the reflectors. Utilization of modern interpretation software such as PETREL and GeoTeric® to image the karsts morphology make it possible to model the karst network within the buried carbonate platform used in this study. Using combination of different seismic attributes such as Variance, Conformance, Continuity, Amplitude, Frequency and Edge attributes, we are able to image the karsts features that are available in the proven gas-field in Central Luconia Province, Malaysia. The mentioned attributes are excellent in visualize and image the stratigraphic features based on the difference in their acoustic impedance as well as structural features, which include karst. 2D & 3D Karst Models were developed to give a better understanding on the characteristics of the identified karsts. From the models, it is found that the karsts are concentrated in the top part of the carbonate reservoir (epikarst) and the middle layer with some of them becomes extensive and create karst networks, either laterally or vertically. Most of the vertical network karst are related to the existence of faults that displaced all the horizons in the carbonate platform.

  6. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    Science.gov (United States)

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-08-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  7. Karst collapse in cities and mining areas, China

    International Nuclear Information System (INIS)

    Jian Chen

    1988-01-01

    Karst collapse is a dynamic geological phenomenon, in which the rock mass or deposits overlying the karstified zone subsides down along the karst cavity, resulting in a collapse pit or sinkhole. After discussing the typical examples of collapse emerging in the karst cities and mines in provinces and regions of South China, such as Guangdong, Guangxi, Hunan, Hubei, Zhejiang, Yunnan, Guizhou, and Jiangxi, it is considered that human activities of economy and production have become a major effect in causing karst collapse. Man-made collapses make 66.4 percent of the total, whereas natural ones 33.6 percent. Most of the collapses occurred to the area with soil overburden (96.7 percent), only a few in areas of bedrock overburden (3.3 percent). The karst collapses have a close relationship with the extent of karst development, the character and the thickness of overburden, and the dynamic condition of underground water. Collapse usually occurs in those parts of an area that are more intensely karstified, with soil thickness less than 5 m and a high amplitude of water table fluctuation. Many kinds of mechanical effects are caused by pumping or draining on the over-burden and destroying its equilibrium, leading to the collapse. These effects included the support loss and load-added effect, penetrating suffusion, gas explosion, water-hammer, suction pressure erosion, and liquefaction effects. The collapses are the result of varied comprehensive effects, particularly the support loss and load-added, and penetrating suffusion

  8. Past and present management of water resources in karst environments

    Science.gov (United States)

    Parise, Mario

    2010-05-01

    Karst is a very peculiar environment, and has a number of intrinsic features that clearly distinguish it from any other natural setting. Hydrology of karst is dominated by absence or very scarce presence of surface runoff, since water rapidly infiltrates underground through the complex network of conduits and fissures that are at the origin of the development of karst caves. The limited presence of water at the surface represented the main problem to be faced by man, starting from the very first historic phases of establishing settlements in karst territories. As often happens in areas with limited natural resources, man was however able to understand the local environment through observations and direct experience, develop technique in order to collect the limited available water resources, and adapt his way of life to the need of the natural environment. In a few words, a sustainable use of the water resources was reached, that went on for many centuries, allowing development of human settlements and agriculture, and, at the same time, protecting and safeguarding the precious hydric resources. Some of the most typical rural architectures built in karst areas of the Mediterranean Basin can be described as examples of such efforts: from the dry stone walls, to many types of storage-houses or dwellings, known with different names, depending upon the different countries and regions. Dry stone walls, in particular, deserve a particular attention, since they had multiple functions: to delimit the fields and properties, to act as a barrier to soil erosion, to allow terracing the high-gradient slopes, to collect and store water. At this latter aim, dry stone walls were build in order to create a small but remarkable micro-environment, functioning as collectors of moisture and water vapour. In the last centuries, with particular regard to the last decades of XX century, the attention paid by man to the need of the natural environment has dramatically changed. This

  9. Review: Characterization, evolution, and environmental issues of karst water systems in Northern China

    Science.gov (United States)

    Liang, Yongping; Gao, Xubo; Zhao, Chunhong; Tang, Chunlei; Shen, Haoyong; Wang, Zhiheng; Wang, Yanxin

    2018-05-01

    In Northern China, karst systems in widely distributed carbonate rocks are one of the most important water supplies for local inhabitants. Constrained by the specific geological and geomorphological conditions, most karst water in this region is discharged as individual or groups of springs. This paper summarizes the characteristics, chemistry, and environmental quality of these karst systems in Northern China. Five structural models of karst water systems were identified based on the relationships between the karst geological strata and karst groundwater flow fields. These specific structural models may closely relate to the attendant environmental geological issues and consistent risks from pollution. Over the past 40 years, the karst water systems in Northern China have suffered from various environmental problems, including deteriorating water quality, the drying up of springs, a continuous decline in the level of karst water, and so on. Based on the field investigation and previous data, a preliminary summary is provided of the environmental problems related to the development and evolutionary trends of karst water in this region. The results highlight the significant challenges associated with karst water, and it is essential that all segments of society be made aware of the situation in order to demand change. In addition, the study provides a scientific basis for the management, protection, and sustainable utilization of karst water resources.

  10. The use of karst geomorphology for planning, hazard avoidance and development in Great Britain

    Science.gov (United States)

    Cooper, Anthony H.; Farrant, Andrew R.; Price, Simon J.

    2011-11-01

    Within Great Britain five main types of karstic rocks - dolomite, limestone, chalk, gypsum and salt - are present. Each presents a different type and severity of karstic geohazard which are related to the rock solubility and geological setting. Typical karstic features associated with these rocks have been databased by the British Geological Survey (BGS) with records of sinkholes, cave entrances, stream sinks, resurgences and building damage; data for more than half of the country has been gathered. BGS has manipulated digital map data, for bedrock and superficial deposits, with digital elevation slope models, superficial deposit thickness models, the karst data and expertly interpreted areas, to generate a derived dataset assessing the likelihood of subsidence due to karst collapse. This dataset is informed and verified by the karst database and marketed as part of the BGS GeoSure suite. It is currently used by environmental regulators, the insurance and construction industries, and the BGS semi-automated enquiry system. The database and derived datasets can be further combined and manipulated using GIS to provide other datasets that deal with specific problems. Sustainable drainage systems, some of which use soak-aways into the ground, are being encouraged in Great Britain, but in karst areas they can cause ground stability problems. Similarly, open loop ground source heat or cooling pump systems may induce subsidence if installed in certain types of karstic environments such as in chalk with overlying sand deposits. Groundwater abstraction also has the potential to trigger subsidence in karst areas. GIS manipulation of the karst information is allowing Great Britain to be zoned into areas suitable, or unsuitable, for such uses; it has the potential to become part of a suite of planning management tools for local and National Government to assess the long term sustainable use of the ground.

  11. Extending GIS Technology to Study Karst Features of Southeastern Minnesota

    Science.gov (United States)

    Gao, Y.; Tipping, R. G.; Alexander, E. C.; Alexander, S. C.

    2001-12-01

    This paper summarizes ongoing research on karst feature distribution of southeastern Minnesota. The main goals of this interdisciplinary research are: 1) to look for large-scale patterns in the rate and distribution of sinkhole development; 2) to conduct statistical tests of hypotheses about the formation of sinkholes; 3) to create management tools for land-use managers and planners; and 4) to deliver geomorphic and hydrogeologic criteria for making scientifically valid land-use policies and ethical decisions in karst areas of southeastern Minnesota. Existing county and sub-county karst feature datasets of southeastern Minnesota have been assembled into a large GIS-based database capable of analyzing the entire data set. The central database management system (DBMS) is a relational GIS-based system interacting with three modules: GIS, statistical and hydrogeologic modules. ArcInfo and ArcView were used to generate a series of 2D and 3D maps depicting karst feature distributions in southeastern Minnesota. IRIS ExplorerTM was used to produce satisfying 3D maps and animations using data exported from GIS-based database. Nearest-neighbor analysis has been used to test sinkhole distributions in different topographic and geologic settings. All current nearest-neighbor analyses testify that sinkholes in southeastern Minnesota are not evenly distributed in this area (i.e., they tend to be clustered). More detailed statistical methods such as cluster analysis, histograms, probability estimation, correlation and regression have been used to study the spatial distributions of some mapped karst features of southeastern Minnesota. A sinkhole probability map for Goodhue County has been constructed based on sinkhole distribution, bedrock geology, depth to bedrock, GIS buffer analysis and nearest-neighbor analysis. A series of karst features for Winona County including sinkholes, springs, seeps, stream sinks and outcrop has been mapped and entered into the Karst Feature Database

  12. Stochastic simulation of karst conduit networks

    Science.gov (United States)

    Pardo-Igúzquiza, Eulogio; Dowd, Peter A.; Xu, Chaoshui; Durán-Valsero, Juan José

    2012-01-01

    Karst aquifers have very high spatial heterogeneity. Essentially, they comprise a system of pipes (i.e., the network of conduits) superimposed on rock porosity and on a network of stratigraphic surfaces and fractures. This heterogeneity strongly influences the hydraulic behavior of the karst and it must be reproduced in any realistic numerical model of the karst system that is used as input to flow and transport modeling. However, the directly observed karst conduits are only a small part of the complete karst conduit system and knowledge of the complete conduit geometry and topology remains spatially limited and uncertain. Thus, there is a special interest in the stochastic simulation of networks of conduits that can be combined with fracture and rock porosity models to provide a realistic numerical model of the karst system. Furthermore, the simulated model may be of interest per se and other uses could be envisaged. The purpose of this paper is to present an efficient method for conditional and non-conditional stochastic simulation of karst conduit networks. The method comprises two stages: generation of conduit geometry and generation of topology. The approach adopted is a combination of a resampling method for generating conduit geometries from templates and a modified diffusion-limited aggregation method for generating the network topology. The authors show that the 3D karst conduit networks generated by the proposed method are statistically similar to observed karst conduit networks or to a hypothesized network model. The statistical similarity is in the sense of reproducing the tortuosity index of conduits, the fractal dimension of the network, the direction rose of directions, the Z-histogram and Ripley's K-function of the bifurcation points (which differs from a random allocation of those bifurcation points). The proposed method (1) is very flexible, (2) incorporates any experimental data (conditioning information) and (3) can easily be modified when

  13. Mechanism of water inrush in tunnel construction in karst area

    Directory of Open Access Journals (Sweden)

    Liping Li

    2016-05-01

    Full Text Available With the rapid developing trend of long, large and deep construction characteristics for underground engineering in the world, China has the largest number of karst tunnels with the wide scales and great difficulties. As the hydrogeological conditions are becoming unprecedentedly complex, water inrush disaster becomes the bottleneck problem for the further development of traffic tunnels. Based on the statistical analysis of a large number of cases of water inrush in karst tunnels, influence factors of water inrush have been put forward from the view of karst hydrogeological factors and engineering disturbance of human factors. Karst hydrogeological factors include geological defect, strata dip, formation lithology, landform and underground level. Human factors of engineering disturbance include excavation and reinforcement geological prediction, monitoring and measurement of surrounding rock. It also introduces some geological disasters caused by the water inrush in tunnel excavation. In terms of the formation of water inrush channel, water inrush types are divided into geological defects inrush, non-geological defects inrush and the combination. Conclusions will be beneficial to further research on hazards control of underground construction.

  14. Study on comprehensive planning of rocky desertification in karst area of Chongqing

    Science.gov (United States)

    Zang, Yajun

    2017-11-01

    Chongqing is a key area for comprehensive treatment of rocky desertification in karst areas of china. Strengthening the comprehensive management of karst rocky desertification area, for the maintenance of ecological safety of Three Gorges Reservoir area, expanding the karst rocky desertification area people survival and development space, and improving the regional ecological conditions, have important practical significance to the construction of ecological civilization and building a harmonious society. Based on the investigation, analysis and arrangement of the data in the rocky desertification area, the paper puts forward the corresponding measures and phased targets for the treatment of the Rocky Desertification in the karst areas of Chongqing.

  15. Geochemical study of evaporite and clay mineral-oxyhydroxide samples from the Waste Isolation Pilot Plant site

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1993-06-01

    Samples of clay minerals, insoluble oxyhydroxides, and their host evaporites from the WIPP site have been studied for their major and minor elements abundances, x-ray diffraction characteristics, K-Ar ages, and Rb-Sr ages. This study was undertaken to determine their overall geochemical characteristics and to investigate possible interactions between evaporates and insoluble constituents. The evaporite host material is water-soluble, having Cl/Br ratios typical of marine evaporites, although the Br content is low. Insoluble material (usually a mixture of clay minerals and oxyhydroxide phases) yields very high Cl/Br ratios, possibly because of Cl from admixed halide minerals. This same material yields K/Rb and Th/U ratios in the normal range for shales; suggesting little, if any, effect of evaporite-induced remobilization of U, K, or Rb in the insoluble material. The rare-earth element (REE) data also show normal REE/chondrite (REE/CHON) distribution patterns, supporting the K/Rb and Th/U data. Clay minerals yield K-Ar dates in the range 365 to 390 Ma and a Rb-Sr isochron age of 428 ± 7 Ma. These ages are well in excess of the 220- to 230-Ma formational age of the evaporites, and confirm the detrital origin of the clays. The ages also show that any evaporite or clay mineral reactions that might have occurred at or near the time of sedimentation and diagenesis were not sufficient to reset the K-Ar and Rb-Sr systematics of the clay minerals. Further, x-ray data indicate a normal evaporitic assemblage of clay minerals and Fe-rich oxyhydroxide phases. The clay minerals and other insoluble material appear to be resistant to the destructive effects of their entrapment in the evaporites, which suggests that these insoluble materials would be good getters for any radionuclides (hypothetically) released from the storage of radioactive wastes in the area

  16. A new species of karst-adapted Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from a threatened karst region in Pahang, Peninsular Malaysia.

    Science.gov (United States)

    Grismer, L Lee; Wood, Perry L; Mohamed, Maketab; Chan, Kin Onn; Heinz, Heather M; Sumarli, Alex S-I; Chan, Jacob A; Loredo, Ariel I

    2013-12-12

    A new species of karst-adapted gekkonid lizard of the genus Cnemaspis Strauch is described from Gua Gunting and Gua Goyang in a karst region of Merapoh, Pahang, Peninsular Malaysia whose unique limestone formations are in immediate danger of being quarried. The new species differs from all other species of Cnemaspis based on its unique suite of morphological and color pattern characters. Its discovery underscores the unique biodiversity endemic to karst regions and adds to a growing list of karst-adapted reptiles from Peninsular Malaysia. We posit that new karst-adapted species endemic to limestone forests will continue to be discovered and these regions will harbor a significant percentage of Peninsular Malaysia's biodiversity and thusly should be conserved rather than quarried.

  17. Hydrochemistry and coal mining activity induced karst water quality degradation in the Niangziguan karst water system, China.

    Science.gov (United States)

    Zhang, Xiaobo; Li, Xue; Gao, Xubo

    2016-04-01

    Hydrogeochemical analysis, statistical analysis, and geochemical modeling were employed to evaluate the impacts of coal mining activities on karst water chemistry in Niangziguan spring catchment, one of the largest karst springs in Northern China. Significant water quality deterioration was observed along the flow path, evidenced from the increasing sulfate, nitrate, and TDS content in karst water. Karst water samples are Ca-Mg-HCO3 type in the recharge areas, Ca-Mg-HCO3-SO4 type in the coal mining areas, and Ca-Mg-SO4-HCO3/HCO3-SO4 type in the rural areas and discharge areas. A four-factor principal component analysis (PCA) model is conducted which explains over 82.9% of the total variation. Factor 1, which explained the largest portion (45.33%) of the total variance, reveals that coal mining activities and natural water-rock interaction as the primary factors controlling karst water quality. Anthropogenic effects were recognized as the secondary factor with high positive loadings for NO3 (-) and Cl(-) in the model. The other two factors are co-precipitation removal of trace elements and silicate mineral dissolution, which explained 20.96% of the total variance. A two-end mixing modeling was proposed to estimate the percentage of coal wastewater giving on karst water chemistry, based on the groundwater sulfate chemistry constrains rather than sulfur isotopes. Uncertainty of sulfur isotope sources led to an overestimation of coal mining water contribution. According to the results of the modeling, the contribution of coal mining waste on karst water chemistry was quantified to be from 27.05 to 1.11% which is ca. three times lower than the values suggested using a sulfur isotope method.

  18. Research in karst aquifers developed in high-mountain areas combining KARSYS models with springs discharge records. Picos de Europa, Spain

    Science.gov (United States)

    Ballesteros, Daniel; Meléndez, Mónica; Malard, Arnauld; Jiménez-Sánchez, Montserrat; Heredia, Nemesio; Jeannin, Pierre-Yves; García-Sansegundo, Joaquín

    2014-05-01

    The study of karst aquifers developed in high-mountain areas is quite complex since the application of many techniques of hydrogeology in these areas is difficult, expensive, and requires many hours of field work. In addition, the access to the study area is usually conditioned by the orography and the meteorological conditions. A pragmatic approach to study these aquifers can be the combination of geometric models of the aquifer with the monitoring of the discharge rate of springs and the meteorological records. KARSYS approach (Jeannin et al. 2013) allows us to elaborate a geometric model of karst aquifers establishing the boundaries of the groundwater bodies, the main drainage axes and providing evidences of the catchment delineation of the springs. The aim of this work is to analyse the functioning of the karst aquifer from the western and central part of the Picos de Europa Mountains (Spain) combining the KARSYS approach, the discharge record from two springs and the meteorological records (rain, snow and temperature). The Picos de Europa (North Spain) is a high-mountains area up to 2.6 km altitude with 2,500 mm/year of precipitations. The highest part of these mountains is covered by snow four to seven months a year. The karst aquifer is developed in Carboniferous limestone which is strongly compartmentalized in, at least, 17 groundwater bodies. The method of work includes: 1) the elaboration of a hydrogeological 3D model of the geometry of the karst aquifers by KARSYS approach, 2) the definition of the springs catchment areas based on the hydrogeological 3D model, 3) the selection of two representative springs emerging from the aquifers to study it, 4) the continuous monitoring of water levels in two karst springs since October 2013, 5) the transformation of the water level values to flow values using height-stream relation curves constructed by measures of the spring discharge, and 5) the comparison of the spring discharge rate records and meteorological

  19. Evaluating Weather Research and Forecasting Model Sensitivity to Land and Soil Conditions Representative of Karst Landscapes

    Science.gov (United States)

    Johnson, Christopher M.; Fan, Xingang; Mahmood, Rezaul; Groves, Chris; Polk, Jason S.; Yan, Jun

    2018-03-01

    sensitivity responses are found over the karst regions, including pronounced warming and cooling effects on the near-surface atmosphere from barren and forested land cover, respectively; (3) the barren ground in the karst regions provides conditions favourable for convective development under certain conditions. Therefore, it is suggested that karst and non-karst landscapes should be distinguished, and their physical processes should be considered for future model development.

  20. Modern and Unconventional Approaches to Karst Hydrogeology

    Science.gov (United States)

    Sukop, M. C.

    2017-12-01

    Karst hydrogeology is frequently approached from a hydrograph/statistical perspective where precipitation/recharge inputs are converted to output hydrographs and the conversion process reflects the hydrology of the system. Karst catchments show hydrological response to short-term meteorological events and to long-term variation of large-scale atmospheric circulation. Modern approaches to analysis of these data include, for example, multiresolution wavelet techniques applied to understand relations between karst discharge and climate fields. Much less effort has been directed towards direct simulation of flow fields and transport phenomena in karst settings. This is primarily due to the lack of information on the detailed physical geometry of most karst systems. New mapping, sampling, and modeling techniques are beginning to enable direct simulation of flow and transport. A Conduit Flow Process (CFP) add-on to the USGS ModFlow model became available in 2007. FEFLOW and similar models are able to represent flows in individual conduits. Lattice Boltzmann models have also been applied to flow modeling in karst systems. Regarding quantitative measurement of karst system geometry, at scales to 0.1 m, X-ray computed tomography enables good detection of detailed (sub-millimeter) pore space in karstic rocks. Three-dimensional printing allows reconstruction of fragile high porosity rocks, and surrogate samples generated this way can then be subjected to laboratory testing. Borehole scales can be accessed with high-resolution ( 0.001 m) Digital Optical Borehole Imaging technologies and can provide virtual samples more representative of the true nature of karst aquifers than can obtained from coring. Subsequent extrapolation of such samples can generate three-dimensional models suitable for direct modeling of flow and transport. Finally, new cave mapping techniques are beginning to provide information than can be applied to direct simulation of flow. Due to flow rates and cave

  1. Method of calculating pilestrip foundations in case of karst hole formation

    Directory of Open Access Journals (Sweden)

    Gotman Al'fred Leonidovich

    2014-02-01

    Full Text Available The paper presents pile strip foundations in the areas with karst risk. The analysis of karst hole formation mechanism shows the lateral soil pressure on the piles caused by the downfallen soil on the hole rims, which transfers around the hole edges during karst hole formation. In this case, the horizontal pressure of the pile reactive force in the area of the pile connection with the raft is transferred to the raft. Pile failure at the hole boundaries will lead to the increase of the raft bearing distance above the karst hole. The inadequate raft bearing capacity can provoke the emergency situation. The existing Codes on karst protective foundations design do not contain the analysis of pile and raft horizontal pressure under the downfallen soil.The goal of this work is to develop the method of pile strip foundations analysis in the areas with karst risk in case of karst hole formation. The analysis of stress-strain state of the system “foundation soil — pile foundation” was carried out using numerical modeling in geotechnical program MIDAS GTS. As a result of numerical investigations, the diagrams of lateral soil pressure onto the piles and the raft are plotted. The pile pressure is approximated with the linear or bilinear function in dependence on geometrical dimensions of the karst hole and strength characteristics of soil that generates the horizontal pressure.In the Codes, the analysis of a pile under lateral soil pressure is given for a pile with the free end. In the problem examined, the pile head has the hinged bearing in place of the connection with the raft. In view of the given boundary data, the pile design scheme is plotted. The inner forces and displacements of the pile are determined by integrating the differential equation of a pile bending. The consistent integrations are evaluated out of the boundary conditions. The boundary values of inner forces and displacements are evaluated from the equality conditions of

  2. The role of karst in engineering and environmental geosciences

    Directory of Open Access Journals (Sweden)

    H. C. Ho

    2011-08-01

    Full Text Available Karst is a unique landform developed by soluble rock. It usually relates to the groundwater drainage system, and provides important water resources. Current researches indicate that karst is closely related to the Earth system and environmental protection, and it can also create potential natural hazards such as sinkhole flooding and land subsidence in urban area. Its relationship with hydrogeology has also been an important factor for studying water pollution and nutrient cycles in engineering geosciences and agricultural geology.

  3. Submerged karst landforms observed by multibeam bathymetric survey in Nagura Bay, Ishigaki Island, southwestern Japan

    Science.gov (United States)

    Kan, Hironobu; Urata, Kensaku; Nagao, Masayuki; Hori, Nobuyuki; Fujita, Kazuhiko; Yokoyama, Yusuke; Nakashima, Yosuke; Ohashi, Tomoya; Goto, Kazuhisa; Suzuki, Atsushi

    2015-01-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the southern Ryukyu Islands, Japan. The coastal seafloor at depths shallower than ~ 130 m has been subjected to repeated and alternating subaerial erosion and sedimentation during periods of Quaternary sea-level lowstands. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. Although these submerged karst landforms are covered by thick postglacial reef and reef sediments, their shapes and sizes are distinct from those associated with coral reef geomorphology. The submerged landscape of Nagura Bay likely formed during multiple glacial and interglacial periods. According to our bathymetric results and the aerial photographs of the coastal area, this submerged karst landscape appears to have developed throughout Nagura Bay (i.e., over an area of approximately 6 × 5 km) and represents the largest submerged karst in Japan.

  4. Applications of GIS and database technologies to manage a Karst Feature Database

    Science.gov (United States)

    Gao, Y.; Tipping, R.G.; Alexander, E.C.

    2006-01-01

    This paper describes the management of a Karst Feature Database (KFD) in Minnesota. Two sets of applications in both GIS and Database Management System (DBMS) have been developed for the KFD of Minnesota. These applications were used to manage and to enhance the usability of the KFD. Structured Query Language (SQL) was used to manipulate transactions of the database and to facilitate the functionality of the user interfaces. The Database Administrator (DBA) authorized users with different access permissions to enhance the security of the database. Database consistency and recovery are accomplished by creating data logs and maintaining backups on a regular basis. The working database provides guidelines and management tools for future studies of karst features in Minnesota. The methodology of designing this DBMS is applicable to develop GIS-based databases to analyze and manage geomorphic and hydrologic datasets at both regional and local scales. The short-term goal of this research is to develop a regional KFD for the Upper Mississippi Valley Karst and the long-term goal is to expand this database to manage and study karst features at national and global scales.

  5. Multi-component and multi-array TEM detection in karst tunnels

    International Nuclear Information System (INIS)

    Sun, Huaifeng; Li, Shucai; Su, Maoxin; Xue, Yiguo; Li, Xiu; Qi, Zhipeng

    2012-01-01

    Emerging applications of transient electromagnetic methods (TEM) in tunnelling require higher resolution on the distributions and shapes of low resistivity bodies, such as karst water and karst pipes, using multi-component and multi-array receivers. However, there are no apparent resistivity definitions for both vertical and horizontal components with offsets inside the loop. Although the raw field can show the differences of the earth electric structure, it is not straightforward. Apparent resistivity is very convenient and easy for engineers. We have developed a method for multi-component and multi-array TEM which can be applied in tunnelling and defined the expressions of apparent resistivity. This method takes advantage of the difference in resolution among components. A homogeneous half-space model and four typical three-layered models are used to test the effectiveness of the new definition. A field case history is carried out and analysed to demonstrate the viability of this technique. The results suggest that it is feasible to use the technique in tunnelling, especially for identifying the spatial distribution of karst water and karst pipes. (paper)

  6. Hydrogeological characterization and environmental effects of the deteriorating urban karst groundwater in a karst trough valley: Nanshan, SW China

    Science.gov (United States)

    Jiang, Yongjun; Cao, Min; Yuan, Daoxian; Zhang, Yuanzhu; He, Qiufang

    2018-02-01

    The unique hydrogeology of karst makes the associated groundwater respond quickly to rainfall events and vulnerable to anthropogenic pollutions. In this study, high-frequency monitoring of spring discharge, temperature, electrical conductivity (EC) and pH, along with monthly hydrochemical and microbial analyses, was undertaken at the outlet of Laolondong karst underground river in Nanshan, southwestern China. The aim was to explore the environmental effects of the catchment's urban area on the karst groundwater resources. The monitoring data of a tracer test and the response of discharge to rainfall events demonstrate that conduits and narrow fissures coexist in the Laolongdong karst aquifer. The EC, Na+, Cl- and SO4 2- values (840 μS/cm, 33.7, 38.6 and 137.2 μg/L, respectively), along with high concentrations of fecal coliform bacteria, at the outlet indicate considerable urban pollution in this area. The contaminants sulfate and nitrate showed different relationships with discharge and EC in different stages of a rainfall event. This behavior provided information about aquifer structure and the influence of transport properties. Meanwhile, the hydrological processes of groundwater flow could be modified by urbanization and result in increasing magnitude of urban floods in the underground river. In addition, sulfuric and nitric acids introduced by urbanization not only impact the karst groundwater quality, but also result in a significant perturbation to the carbon cycling system in the karst area.

  7. Highway runoff in areas of karst topography.

    Science.gov (United States)

    2004-01-01

    Karst terrain is characterized by sinkholes, depressions, caves, and underground drainage, generally underlain by soluble rocks such as limestone and dolomite. Because natural filtration through soil is limited in karst areas, pollutants in highway s...

  8. Simulating flow in karst aquifers at laboratory and sub-regional scales using MODFLOW-CFP

    Science.gov (United States)

    Gallegos, Josue Jacob; Hu, Bill X.; Davis, Hal

    2013-12-01

    Groundwater flow in a well-developed karst aquifer dominantly occurs through bedding planes, fractures, conduits, and caves created by and/or enlarged by dissolution. Conventional groundwater modeling methods assume that groundwater flow is described by Darcian principles where primary porosity (i.e. matrix porosity) and laminar flow are dominant. However, in well-developed karst aquifers, the assumption of Darcian flow can be questionable. While Darcian flow generally occurs in the matrix portion of the karst aquifer, flow through conduits can be non-laminar where the relation between specific discharge and hydraulic gradient is non-linear. MODFLOW-CFP is a relatively new modeling program that accounts for non-laminar and laminar flow in pipes, like karst caves, within an aquifer. In this study, results from MODFLOW-CFP are compared to those from MODFLOW-2000/2005, a numerical code based on Darcy's law, to evaluate the accuracy that CFP can achieve when modeling flows in karst aquifers at laboratory and sub-regional (Woodville Karst Plain, Florida, USA) scales. In comparison with laboratory experiments, simulation results by MODFLOW-CFP are more accurate than MODFLOW 2005. At the sub-regional scale, MODFLOW-CFP was more accurate than MODFLOW-2000 for simulating field measurements of peak flow at one spring and total discharges at two springs for an observed storm event.

  9. Field observations of extended seawater intrusion through subsurface karst conduit networks at Wakulla Spring in the Woodville Karst Plain, Florida

    Science.gov (United States)

    Xu, Z.; Bassett, S.; Hu, B. X.; Dyer, S.

    2016-12-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electric conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 14 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This abstract documented the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  10. State-space prediction of spring discharge in a karst catchment in southwest China

    Science.gov (United States)

    Li, Zhenwei; Xu, Xianli; Liu, Meixian; Li, Xuezhang; Zhang, Rongfei; Wang, Kelin; Xu, Chaohao

    2017-06-01

    Southwest China represents one of the largest continuous karst regions in the world. It is estimated that around 1.7 million people are heavily dependent on water derived from karst springs in southwest China. However, there is a limited amount of water supply in this region. Moreover, there is not enough information on temporal patterns of spring discharge in the area. In this context, it is essential to accurately predict spring discharge, as well as understand karst hydrological processes in a thorough manner, so that water shortages in this area could be predicted and managed efficiently. The objectives of this study were to determine the primary factors that govern spring discharge patterns and to develop a state-space model to predict spring discharge. Spring discharge, precipitation (PT), relative humidity (RD), water temperature (WD), and electrical conductivity (EC) were the variables analyzed in the present work, and they were monitored at two different locations (referred to as karst springs A and B, respectively, in this paper) in a karst catchment area in southwest China from May to November 2015. Results showed that a state-space model using any combinations of variables outperformed a classical linear regression, a back-propagation artificial neural network model, and a least square support vector machine in modeling spring discharge time series for karst spring A. The best state-space model was obtained by using PT and RD, which accounted for 99.9% of the total variation in spring discharge. This model was then applied to an independent data set obtained from karst spring B, and it provided accurate spring discharge estimates. Therefore, state-space modeling was a useful tool for predicting spring discharge in karst regions in southwest China, and this modeling procedure may help researchers to obtain accurate results in other karst regions.

  11. Identification of Hydrochemical Function and Behavior of the Houzhai Karst Basin, Guizhou Province, Southwestern China

    Directory of Open Access Journals (Sweden)

    Xian Li

    2018-01-01

    Full Text Available Due to the difference of geomorphology and the development of fractures, the hydrochemical function and behavior appear to be complex. Variations of karst water conductivity can reflect the contribution of different runoff sources and thus indirectly reflect the development characteristics of conduits and fractures. Taking Houzhai karst system (southwestern China as a case study, the frequency distribution curves of karst water conductivity were decomposed by Gaussian Mixture Analysis to identify the runoff components of different karst landform. The dominant runoff types had been distinguished, and the relative contribution of the different water types had been investigated. The results showed that the karst flow types were slope flow, rapid fracture flow, and slow fracture flow. Rapid fracture flow was the major recharge type of Houzhai karst water system. Slow fracture flow in the downstream area accounted for a larger proportion than that of the upstream area. The relative contribution of the different runoff components showed that the upstream area was a rapid flow area of conduit structure with low storage capacity, the downstream area was an aquifer spatial structure of netted fissure conduit with high storage capacity, and the midstream area was a transitional zone between the upstream and downstream area.

  12. International symposium and field seminar on karst waters and environmental impacts. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Gunay, G; Tezcan, L; Atilla, A O [comps.

    1996-12-31

    The international symposium and field seminar on karst waters and environmental impacts was held on 10-20 September 1995 in Beldibi,Antalya, Turkey. The specialists discussed COST Action 65, Environmental Impact sand Legal Aspects, Engineering and Environmental Impacts of Karst, Research Methods, Tracing Techniques, Hydro chemistry, Environmental Isotopes in Karst, Transport Processing, Modeling and Flow Systems, Karst Morphology and Paleoenvironment, Regional Karst Systems, James F. Quinlay Pollution Control and Karst Water Protection Session and Hydrology. Almost 140 papers were presented in the meeting.

  13. International symposium and field seminar on karst waters and environmental impacts. Abstracts

    International Nuclear Information System (INIS)

    Gunay, G.; Tezcan, L.; Atilla, A.O.

    1995-01-01

    The international symposium and field seminar on karst waters and environmental impacts was held on 10-20 September 1995 in Beldibi,Antalya, Turkey. The specialists discussed COST Action 65, Environmental Impact sand Legal Aspects, Engineering and Environmental Impacts of Karst, Research Methods, Tracing Techniques, Hydro chemistry, Environmental Isotopes in Karst, Transport Processing, Modeling and Flow Systems, Karst Morphology and Paleoenvironment, Regional Karst Systems, James F. Quinlay Pollution Control and Karst Water Protection Session and Hydrology. Almost 140 papers were presented in the meeting

  14. A review of stormwater management in karst

    Science.gov (United States)

    Stormwater management can be a challenge in any environment, but it is especially difficult in karst terrain. The characteristic dissolution of bedrock creates depressions in topography as well as voids in the subsurface, resulting in problems such as collapse sinkhole development, groundwater cont...

  15. Disposal of radioactive waste in evaporite formations - a review of published radiological assessments and their relevance to the UK

    International Nuclear Information System (INIS)

    Lawson, G.

    1983-11-01

    Radiological assessments of the disposal of radioactive waste in evaporite formations, principally halite, have been reviewed. These assessments were carried out in the USA, the Netherlands, Denmark and West Germany. The general nature of evaporite formations in the UK is discussed and comments are given on the broad relevance of the assessments to the potential disposal of radioactive waste in UK evaporite formations. (author)

  16. Hydraulic characterisation of karst systems with man-made tracers

    International Nuclear Information System (INIS)

    Werner, A.

    1998-01-01

    Tracer experiments using man-made tracers are common in hydrogeological exploration of groundwater aquifers in karst systems. In the present investigation, a convection-dispersion model (multidispersion model with consideration of several flow paths) and a single-cleft model (consideration of the diffusion between the cleft and the surrounding rock matrix) were used for evaluating tracer experiments in the main hydrological system of the saturated zone of karst systems. In addition to these extended analytical solutions, a numerical transport model was developed for investigating the influence of the transient flow rate on the flow and transport parameters. Comparative evaluations of the model approaches for the evaluation of tracer experiments were made in four different karst systems: Danube-Aach, Paderborn, Slowenia and Lurbach, of which the Danube-Aach system was considered as the most important. The investigation also comprised three supplementary experiments in order to enable a complete hydraulic characterisation of the system. (orig./SR) [de

  17. Evaluation of subsidence hazard in mantled karst setting: a case study from Val d'Orléans (France)

    Science.gov (United States)

    Perrin, Jérôme; Cartannaz, Charles; Noury, Gildas; Vanoudheusden, Emilie

    2015-04-01

    Soil subsidence/collapse is a major geohazard occurring in karst region. It occurs as suffosion or dropout sinkholes developing in the soft cover. Less frequently it corresponds to a breakdown of karst void ceiling (i.e., collapse sinkhole). This hazard can cause significant engineering challenges. Therefore decision-makers require the elaboration of methodologies for reliable predictions of such hazards (e.g., karst subsidence susceptibility and hazards maps, early-warning monitoring systems). A methodological framework was developed to evaluate relevant conditioning factors favouring subsidence (Perrin et al. submitted) and then to combine these factors to produce karst subsidence susceptibility maps. This approach was applied to a mantled karst area south of Paris (Val d'Orléans). Results show the significant roles of the overburden lithology (presence/absence of low-permeability layer) and of the karst aquifer piezometric surface position within the overburden. In parallel, an experimental site has been setup to improve the understanding of key processes leading to subsidence/collapse and includes piezometers for measurements of water levels and physico-chemical parameters in both the alluvial and karst aquifers as well as surface deformation monitoring. Results should help in designing monitoring systems to anticipate occurrence of subsidence/collapse. Perrin J., Cartannaz C., Noury G., Vanoudheusden E. 2015. A multicriteria approach to karst subsidence hazard mapping supported by Weights-of-Evidence analysis. Submitted to Engineering Geology.

  18. Considerations on the parent material in the soil developed on the evaporite deposits from Stana (Cluj district

    Directory of Open Access Journals (Sweden)

    Horea Bedelean

    2003-09-01

    Full Text Available This research concerned three profiles developed on Eocene (Priabonian gypsum parent material from Stana (Cluj district in order to investigate their properties. The soil and parent material samples were collected from individual horizons in each profile. Both the mineralogical and structural-textural features of the parent material (evaporitic deposits reflect the depositional context. From a mineralogical point of view, the deposits are represented by gypsum, and anhydrite. Typical sulfate facies are present: laminitic, nodular, gypscretic, and entherolitic. Physical and mineralogical properties of the soil layers were determined in the laboratory. The field observations and the results of the analyses allowed us to classify the soil as a rendzinic regosol, according to the Romanian System of Soil Taxonomy (S.R.T.S. 2000.

  19. 76 FR 61379 - Final Recovery Plan, Bexar County Karst Invertebrates

    Science.gov (United States)

    2011-10-04

    ...] Final Recovery Plan, Bexar County Karst Invertebrates AGENCY: Fish and Wildlife Service, Interior... availability of our final recovery plan, for the nine Bexar County Karst Invertebrates under the Endangered... County karst invertebrates were listed as endangered species on December 26, 2000 (65 FR 81419): Rhadine...

  20. Hidrogeological features of carbonate karst

    Directory of Open Access Journals (Sweden)

    Валерій Васильович Сухов

    2015-07-01

    Full Text Available On the example of loamy-chalky Upper Cretaceous strata (K2cm of Sviatogirsk brachyanticline it has been found out that carbonate karst forms with the participation of different on dynamics and chemical composition kinds of groundwater.Basic chemical reactions that lead to leaching and dissolution of carbonate rocks during their interaction with groundwater have been characterized. Geological, hydrogeological and geochemical conditions of formation of various morphogenetic types of karst - surface (epikarst and deep (hypokarst have been well-grounded.

  1. The Role of Attached and Free-Living Bacteria in Biodegradation in Karst Aquifers

    Directory of Open Access Journals (Sweden)

    Ahmad Kheder

    2011-12-01

    Full Text Available Natural attenuation of groundwater contamination occurs at some level for all aquifers impacted with organic contaminants. The issues regarding natural attenuation are whether it takes place at a sufficient rate to be protective of human health and the environment. Implementation of a Monitored Natural Attenuation (MNA remedial alternative for groundwater requires parties responsible for the contamination to demonstrate to regulators and the public that MNA is protective at a given site. Analysis of MNA for remediation of karst aquifers is hampered by a lack of understanding of biodegradation in karst environments. The lack of studies examining biodegradation in karst aquifers may in large part be due to the widespread perception that contaminants are rapidly flushed out of karst aquifers resulting in insufficient residence times for contaminants to biodegrade. In highly developed and well-connected conduit systems, the rate of contaminant migration is perceived to be much faster than the rate of biodegradation. This perception of contaminant transport is largely incorrect. Tracer studies for karst aquifers often indicate that these aquifers are characterized by diverse flow regimes and storage capabilities. Additionally, it is also believed that if bioremediation in bedrock aquifers is dependent upon contact between surface-attached bacteria and contaminants, then bioremediation would be limited by the low surface-area-to-volume ratio (SA/V of karst aquifers. A quantitative basis, however, for accepting or rejecting the assumption that attached bacteria dominate the biodegradation process in karst conduits has not been shown. The objective of this research was to determine if free-living karst bacteria from contributed as much to toluene biodegradation as attached bacteria. This is an important area of research. Research indicates bacteria are both attached and free-living in karst aquifers and it is unrealistic to think that only the attached

  2. Frictional properties and slip stability of active faults within carbonate-evaporite sequences: The role of dolomite and anhydrite

    NARCIS (Netherlands)

    Scuderi, M.M.; Niemeijer, A.R.; Collettini, C.; Marone, C.

    2013-01-01

    Seismological observations show that many destructive earthquakes nucleate within, or propagate through, thick sequences of carbonates and evaporites. For example, along the Apennines range (Italy) carbonate and evaporite sequences are present at hypocentral depths for recent major earthquakes

  3. Some cases of terrain unstability from the Dolenjska karst area

    Directory of Open Access Journals (Sweden)

    Magda Čarman

    2010-12-01

    Full Text Available The paper presents some cases of terrain unstability from the Dolenjska karst area formed in the last yearsaround Žužemberk and Dolenjske Toplice. The Dolenjska karst has its own characteristic way of development. Themain features are thick soil top, mainly composed of clay, and high and strongly fluctuating water table. Presentedare a landslide, two rockfalls and a sinkhole collapse. A landslide nearby Žužemberk was initiated in soil top. Bothrockfalls appeared in tectonically highly disturbed carbonate rocks along the Žužemberk fault. The sinkhole collapsein the area around Dolenjske Toplice developed in tectonically damaged rocks inside the Dolenjska - Notranjskahorst and during a period of heavy rain.

  4. Seismic Characterization of Hypogenic Karst Systems Associated with Deep Hydrothermal Fluids in the Middle-Lower Ordovician Yingshan Formation of the Shunnan Area, Tarim Basin, NW China

    Directory of Open Access Journals (Sweden)

    Hongtao Zhu

    2017-01-01

    Full Text Available Two fundamental forms of hypogenic karst systems (lateral stratiform hypogenic and cross-formational fault-vein hypogenic karst system are distinguished mainly by differential effects of preexisting faults. In seismic cross sections, hypogenic karst systems are expressed as complex string-beads-like seismic reflections associated with faults. In this study, a new seismic characterization workflow was developed including seismic amplitude thresholding, fault interpretation, pickup, and merge display to enhance the description of the spatial distribution and coupling of hypogenic karst system and faults. The results suggest that the lateral stratiform hypogenic karst systems are predominantly developed at the top of the secondary faults, presenting an overall of “layered distribution and finger-like interaction” features. The cross-formational fault-vein hypogenic karst systems are developed around faults and characterized by dendritic distribution. Furthermore, we infer that the development pattern of hypogenic karst systems has been produced by the interplay of the faults, preexisting epigenic karst systems, and lateral carrier-beds, which together combine the complex hydrothermal migration pathways of fluids with the characteristics of vertical and horizontal combined pathways. In addition, some possible controlling factors (e.g., sequence stratigraphic boundaries, paleogeomorphology, and sedimentary facies that can influence the development of these hypogenic karst systems have been discussed in detail.

  5. Karst mapping in the United States: Past, present and future

    Science.gov (United States)

    Weary, David J.; Doctor, Daniel H.

    2015-01-01

    The earliest known comprehensive karst map of the entire USA was published by Stringfield and LeGrand (1969), based on compilations of William E. Davies of the U.S. Geological Survey (USGS). Various versions of essentially the same map have been published since. The USGS recently published new digital maps and databases depicting the extent of known karst, potential karst, and pseudokarst areas of the United States of America including Puerto Rico and the U.S. Virgin Islands (Weary and Doctor, 2014). These maps are based primarily on the extent of potentially karstic soluble rock types, and rocks with physical properties conducive to the formation of pseudokarst features. These data were compiled and refined from multiple sources at various spatial resolutions, mostly as digital data supplied by state geological surveys. The database includes polygons delineating areas with potential for karst and that are tagged with attributes intended to facilitate classification of karst regions. Approximately 18% of the surface of the fifty United States is underlain by significantly soluble bedrock. In the eastern United States the extent of outcrop of soluble rocks provides a good first-approximation of the distribution of karst and potential karst areas. In the arid western states, the extent of soluble rock outcrop tends to overestimate the extent of regions that might be considered as karst under current climatic conditions, but the new dataset encompasses those regions nonetheless. This database will be revised as needed, and the present map will be updated as new information is incorporated.

  6. Karst geomorphology and hydrology of the Shenandoah Valley near Harrisonburg, Virginia

    Science.gov (United States)

    Doctor, Daniel H.; Orndorff, Wil; Maynard, Joel; Heller, Matthew J.; Casile, Gerolamo C.

    2014-01-01

    The karst of the central Shenandoah Valley has characteristics of both shallow and deep phreatic formation. This field guide focuses on the region around Harrisonburg, Virginia, where a number of these karst features and their associated geologic context can be examined. Ancient, widespread alluvial deposits cover much of the carbonate bedrock on the western side of the valley, where shallow karstification has resulted in classical fluviokarst development. However, in upland exposures of carbonate rock, isolated caves exist atop hills not affected by surface processes other than exposure during denudation. The upland caves contain phreatic deposits of calcite and fine-grained sediments. They lack any evidence of having been invaded by surface streams. Recent geologic mapping and LIDAR (light detection and ranging) elevation data have enabled interpretive association between bedrock structure, igneous intrusions, silicification and brecciation of host carbonate bedrock, and the location of several caves and karst springs. Geochemistry, water quality, and water temperature data support the broad categorization of springs into those affected primarily by shallow near-surface recharge, and those sourced deeper in the karst aquifer. The deep-seated karst formation occurred in the distant past where subvertical fracture and fault zones intersect thrust faults and/or cross-strike faults, enabling upwelling of deep-circulating meteoric groundwater. Most caves formed in such settings have been overprinted by later circulation of shallow groundwater, thus removing evidence of the history of earliest inception; however, several caves do preserve evidence of an earlier formation.

  7. Assessment of groundwater quality of the Tatlicay aquifer and relation to the adjacent evaporitic formations (Cankiri, Turkey).

    Science.gov (United States)

    Apaydın, Ahmet; Aktaş, Sibel Demirci

    2012-04-01

    One of the most important hydrogeologic problems in and adjacent areas of evaporitic formations is severe quality degradation of groundwaters. These kinds of groundwaters contain high content of dissolved solids and generally have some limitations for use. Tatlicay basin (north-central Turkey) is an example to effects of the evaporites on groundwater quality in the adjacent alluvium aquifer. Gypsum and anhydrites in the two evaporite formations (Bayindir and Bozkir) effect of the groundwater quality in the alluvium adversely, by dissolution of the evaporites by surface drainage and infiltration into the alluvium aquifer (widespread effect) and by infiltration of low quality gypsum springs (local effect) into the aquifer. Evaporitic formations significantly increased EC, TDS, Ca and SO(4) parameters in the alluvium aquifer in the central and downstream regions. EC has increased roughly from 500-800 to 1,700-2,000 μS/cm, Ca has roughly increased from 3-4 to 10 meq/l, SO(4) has increased 0.5-1 to 11-12 meq/l. Consequently, three clusters were distinguished in the basin; (1) nonevaporitic waters in low TDS, Na, Ca, Mg, Cl and SO(4), (2) diluted waters in high TDS and relatively high Cl, moderate-relatively high Na, Ca, Mg, SO(4), (3) gypsum springs in highest TDS, Ca, SO(4), but moderate Mg and low Na, Cl.

  8. Synchronous onset of the Messinian evaporite precipitation: First Mediterranean offshore evidence

    Science.gov (United States)

    Ochoa, Diana; Sierro, Francisco J.; Lofi, Johanna; Maillard, Agnès; Flores, Jose-Abel; Suárez, Mercedes

    2015-10-01

    The Messinian Salinity Crisis (MSC) was a major ecological crisis affecting shallow and deep-water settings over the entire Mediterranean basin. However, the evolution of the MSC and its ecological impacts have mainly been explained on the basis of sediments from onshore outcrops. Lack of complete and physically connected records from onshore and offshore settings has inhibited comprehensive understanding of basin behaviour during the MSC. Herein we present a continuous record from an intermediate-depth basin on the Balearic Promontory that comprises late Tortonian-Messinian marls and evaporitic beds from the first MSC phase (i.e., Primary Lower Gypsum-PLG stage). Well-log and biostratigraphic data allow us establishing a large-scale calibration to the astronomical solutions, and to correlate pre-MSC sediments with classical rhythmic successions outcropping onshore. Thickness and characteristic sedimentary patterns observed in the offshore evaporitic records resemble those from marginal PLG sequences. Furthermore, seismic reflectors from a Bedded Unit (BU), which corresponds to an evaporitic interval according to well-to-seismic ties, are correlated with the onshore PLG sequences. This correlation constitutes the first attempt to link well-known marginal sequences with intermediate-depth offshore settings, which have previously only been studied through seismic imaging. Our time-calibration provides direct evidence supporting a synchronous onset of the PLG phase between onshore and offshore settings along the southwestern Balearic Promontory margin. Those BU reflectors, which were positively correlated to the PLG, were likely precipitated offshore the continental shelf at Messinian times. These results suggest that gypsum precipitation and/or preservation was not always limited to 200 m water-depths and could occur in non-silled basins. Finally, we only found a major erosion at the top of the PLG sequences, implying that the MSC drawdown occurred after the

  9. A generalized genetic framework for the development of sinkholes and Karst in Florida, U.S.A.

    Science.gov (United States)

    Beck, Barry F.

    1986-03-01

    Karst topography in Florida is developed on the Tertiary limestones of the Floridan aquifer Post-depositional diagenesis and solution have made these limestones highly permeable, T=ca. 50,000 m2/d. Zones of megaporosity have formed at unconformities, and dissolution has enlarged joints and fractures Erosion of the overlying clastic Miocene Hawthorn group strata on one flank of a structural arch has exposed the limestone The elevated edge of the Hawthorn cover forms the Cody scarp Ubiquitous solution pipes have previously formed at joint intersections and are now filled Downwashing of the fill deeper into solution cavities in the limestone and subsidence of the overlying unconsolidated sediments causes surface collapse a subsidence doline or sinkhole This process may penetrate up to 60 m of the semi-consolidated Hawthorn cover, as occurred when the Winter Park sinkhole developed Dense clusters of solution pipes may have formed cenotes which are now found on the exposed limestone terrain Groundwater moves laterally as diffuse flow except where input or outflow is concentrated. At sinking streams, vertical shafts, and springs, karst caves have formed, but only the major sinking streams form through-flowing conduit systems Shaft recharge dissipates diffusely. Spring discharge is concentrated from diffuse flow In both cases, conduits taper and merge into a zone of megaporosity

  10. The Messinian evaporites in the Levant Basin: lithology, deformation and its evolution

    Science.gov (United States)

    Feng, Ye; Steinberg, Josh; Reshef, Moshe

    2017-04-01

    The lithological composition of the Messinian evaporite in the Levant Basin remains controversial and salt deformation mechanisms are still not fully understood, due to the lack of high resolution 3D depth seismic data and well logs that record the entire evaporite sequence. We demonstrate how 3D Pre-stack depth migration (PSDM) and intra-salt tomography can lead to improved salt imaging. Using 3D PSDM seismic data with great coverage and deepwater well log data from recently drilled boreholes, we reveal intra-salt reflective units associated with thin clastic layers and a seismic transparent background consisting of uniform pure halite. Structural maps of all internal reflectors are generated for stratigraphy and attributes analysis. High amplitude fan structures in the lowermost intra-salt reflector are observed, which may indicate the source of the clastic formation during the Messinian Salinity Crisis (MSC). The Messinian evaporite in the Levant Basin comprises six units; the uppermost unit thickens towards the northwest, whereas the other units are uniform in thickness. The top of salt (TS) horizon is relatively horizontal, while all other intra-salt reflectors and base of salt (BS) dip towards the northwest. Different seismic attributes are used for identification of intra-salt deformation patterns. Maximum curvature maps show NW-striking thrust faults on the TS and upper intra-salt units, and dip azimuth maps are used to show different fold orientations between the TS and intra-salt units, which indicate a two-phase deformation mechanism: basin NW tilting as syn-depositional phase and NNE spreading of Plio-Pleistocene overburden as post-depositional phase. RMS amplitude maps are used to identify a channelized system on the TS. An evaporite evolution model during the MSC of the Levant Basin is therefore established based on all the observations. Finally the mechanical properties of the salts will be utilized to explore salt deformation in the Levant Basin

  11. Locating karst depressed columns by means of Rn measurement on the surface

    International Nuclear Information System (INIS)

    Tang Daimao; Liu Hongfu; Duan Hongjie; Duan Lindi; Sui Haichen

    1999-01-01

    The coal mining and the related surface projects are extremely harassed by the underground karst depressed columns. The author discussed the surface Rn concentration's abnormality caused by the karst depressed columns. It is concluded that different kinds of karst depressed column can cause different Rn concentration's abnormality. The α-cup Rn measuring instrument was used for detecting Rn abnormality on the surface in order to locate the underground karst depressed columns

  12. Water resources management in karst aquifers - concepts and modeling approaches

    Science.gov (United States)

    Sauter, M.; Schmidt, S.; Abusaada, M.; Reimann, T.; Liedl, R.; Kordilla, J.; Geyer, T.

    2011-12-01

    established vulnerability assessment techniques ascertain the respective groundwater quality. In this paper a systematic overview is provided on karst groundwater management schemes illustrating the specific conditions allowing active or passive management in the first place as well as the employment of various types of adapted models for the design of the different management schemes. Examples are provided from karst systems in Israel/Palestine, where a large 4000sqkm basin is being managed as a whole, the South of France, where the Lez groundwater development scheme illustrates the optimal use of overpumping from the conduit system, providing additional water for the City of Montpellier during dry summers and at the same time increasing recharge and assisting in the mitigation of flooding during high winter discharge conditions. Overpumping could be an option in many Mediterranean karst catchments since karst conduit development occurred well below today's spring discharge level. Other examples include the construction of subsurface dams for hydropower generation in the Dinaric karst and reduction of discharge. Problems of leakage and general feasibility are discussed.

  13. Peculiarity and vulnerability of karst settings, analyzed through a review of available environmental indices

    Science.gov (United States)

    Parise, Mario; Mazzei, Marianna

    2016-04-01

    Karst is a unique environment on Earth, characterized by a variety of peculiar geological and hydrological features, that are expressed by typical landforms at the surface (doline, ponor, polje, etc.) and underground (single cave, sinkhole, complex hypogean systems consisting of sequences of pits and galleries, etc.). Among the main characters of karst, the direct connection between the surface and the underground is at the origin of the fragility of karst settings, and the related high vulnerability. Many different types of natural geological hazards (or geo-hazards) may potentially affect karst lands, with sinkholes and flash floods being the most frequent and typical. In addition, karst is exposed to a variety of anthropogenic disturbances as well, including loss of natural landscapes, destruction of caves and speleothems, and contamination and pollution problems. At this latter regard, it has to be reminded that karst aquifers host high quality groundwaters, that are used as source of drinking water worldwide, with estimates indicating that the supply of drinking water from karst is going to have a significant increase in the next decades, From all of this, the importance in fully defining the karst setting, and in a detail examination of all the natural and anthropogenic events that may cause negative effects on it, comes out. Uniqueness of karst has been acknowledged since a long time, but only in recent years efforts have been made to develop approaches and methods specifically dedicated to this peculiar environment. Such approaches represent definitely a mandatory step in the correct management of karst terranes, providing useful elements to stakeholders, land managers and people living in karst lands about their fragility, and the need to safeguard them and the natural resources therein contained. Starting from these considerations, in this contribution we review the main environmental indices dedicated to karst that have been recently proposed in the

  14. A geomorphological strategy for conducting environmental impact assessments in karst areas

    Science.gov (United States)

    Veni, George

    1999-12-01

    In their efforts to protect regional groundwater supplies, governmental agencies are increasingly requiring studies of karst areas and their features. In areas where tracer tests or geophysics are not required, funded, or otherwise feasible, geomorphological methods remain as the primary tool for assessing karst. This study proposes a geomorphologically-based environmental impact assessment strategy for karst areas. While it is supported with results from a study of the karstic Edwards Aquifer recharge zone on the Camp Bullis Military Training Installation, TX, USA, it is based on the study of several karst areas and is generalized to accommodate and be fine-tuned for regional variations. Biological and other resource issues can also be assessed with this strategy. The assessment identifies environmentally sensitive features and areas, as is often required to meet regulatory directives. In karst areas with relatively small features, excavation is a key tool for accurate assessment. Although the results of this study will help to better manage karst areas, proper management must be done on a regional scale. The highly permeable nature of karst precludes adequate management solely on a feature-by-feature basis. Studies on the relationship of water quality to impervious cover show adverse environmental impacts significantly increase when impervious cover exceeds 15% of a surface watershed. The Camp Bullis study finds similar impacts in its groundwater drainage basin, supporting the argument of 15% impervious cover as a regionally effective means of also protecting karst aquifers when coupled with protection of critical areas identified by field surveys.

  15. Numerical simulation of freshwater/seawater interaction in a dual-permeability karst system with conduits: the development of discrete-continuum VDFST-CFP model

    Science.gov (United States)

    Xu, Zexuan; Hu, Bill

    2016-04-01

    Dual-permeability karst aquifers of porous media and conduit networks with significant different hydrological characteristics are widely distributed in the world. Discrete-continuum numerical models, such as MODFLOW-CFP and CFPv2, have been verified as appropriate approaches to simulate groundwater flow and solute transport in numerical modeling of karst hydrogeology. On the other hand, seawater intrusion associated with fresh groundwater resources contamination has been observed and investigated in numbers of coastal aquifers, especially under conditions of sea level rise. Density-dependent numerical models including SEAWAT are able to quantitatively evaluate the seawater/freshwater interaction processes. A numerical model of variable-density flow and solute transport - conduit flow process (VDFST-CFP) is developed to provide a better description of seawater intrusion and submarine groundwater discharge in a coastal karst aquifer with conduits. The coupling discrete-continuum VDFST-CFP model applies Darcy-Weisbach equation to simulate non-laminar groundwater flow in the conduit system in which is conceptualized and discretized as pipes, while Darcy equation is still used in continuum porous media. Density-dependent groundwater flow and solute transport equations with appropriate density terms in both conduit and porous media systems are derived and numerically solved using standard finite difference method with an implicit iteration procedure. Synthetic horizontal and vertical benchmarks are created to validate the newly developed VDFST-CFP model by comparing with other numerical models such as variable density SEAWAT, couplings of constant density groundwater flow and solute transport MODFLOW/MT3DMS and discrete-continuum CFPv2/UMT3D models. VDFST-CFP model improves the simulation of density dependent seawater/freshwater mixing processes and exchanges between conduit and matrix. Continuum numerical models greatly overestimated the flow rate under turbulent flow

  16. Modeling of karst deformation and analysis of acoustic emission during sinkhole formation

    Science.gov (United States)

    Bakeev, R. A.; Stefanov, Yu. P.; Duchkov, A. A.; Myasnikov, A. V.

    2017-12-01

    In this paper, the fracture pattern and formation of a sinkhole are estimated depending on the rock properties. The possibility of using geophysical methods for recording and analyzing acoustic emission to monitor and predict the state of the medium is considered. The problem of deformation of the sedimentary cover over the growing karst cavity is solved on the basis of the elastoplastic Drucker-Prager-Nikolaevsky model and the equation of damage accumulation. The specified kinetics of accumulation of damages allows us to describe slow processes of degradation of the strength of the medium under stresses that are low for the development of inelastic deformations. The results are obtained for different values of the strength of karst rock; we show the influence of the kinetic parameters of damage accumulation on the shape of collapse depressions. We also model acoustic emission caused by the material fracture. One can follow different stages of the karst development by looking at patterns of cells which fail at a given time. Our observations show the relation between the intensity of material fracture and the intensity of seismic emission.

  17. Evaluating susceptibility of karst dolines (sinkholes) for collapse in Sango, Tennessee, USA

    Science.gov (United States)

    Siska, Peter P.; Goovaerts, Pierre; Hung, I-K

    2016-01-01

    Dolines or sinkholes are earth depressions that develop in soluble rocks complexes such as limestone, dolomite, gypsum, anhydrite, and halite; dolines appear in a variety of shapes from nearly circular to complex structures with highly curved perimeters. The occurrence of dolines in the studied karst area is not random; they are the results of geomorphic, hydrologic, and chemical processes that have caused partial subsidence, even the total collapse of the land surface when voids and caves are present in the bedrock and the regolith arch overbridging these voids is unstable. In the study area, the majority of collapses occur in the regolith (bedrock cover) that bridges voids in the bedrock. Because these collapsing dolines may result in property damage and even cause the loss of lives, there is a need to develop methods for evaluating karst hazards. These methods can then be used by planners and practitioners for urban and economic development, especially in regions with a growing population. The purpose of this project is threefold: 1) to develop a karst feature database, 2) to investigate critical indicators associated with doline collapse, and 3) to develop a doline susceptibility model for potential doline collapse based on external morphometric data. The study has revealed the presence of short range spatial dependence in the distribution of the dolines’ morphometric parameters such as circularity, the geographic orientation of the main doline axes, and the length-to-width doline ratios; therefore, geostatistics can be used to spatially evaluate the susceptibility of the karst area for doline collapse. The partial susceptibility estimates were combined into a final probability map enabling the identification of areas where, until now, undetected dolines may cause significant hazards. PMID:27616807

  18. The impact of human activities on dolines (sinkholes: Typical geomorphologic features on Karst (Slovenia and possibilities of their preservation

    Directory of Open Access Journals (Sweden)

    Cernatič-Gregorič Anica

    2010-01-01

    Full Text Available This paper focuses on dolines, one of the main geomorphologic features on Karst (Slovenia. Dolines are a dominant surface feature and also a main source of fertile soil on Karst. Consequently they represent a significant element of the Karst landscape and an important part of traditional agricultural land use. Negative impacts due to rapid economic development in the last decade are affecting Karst seriously, mostly by degradation of typical landscape features. The main purpose of our work was to document the current extent of damage caused on dolines and consequently on Karst landscape. The paper discusses the gravity of the problem and points out the insufficiency of current legislation concerning landscape protection. Based on the research results the paper comments on possible consequences if the degradation process continues. .

  19. A New Methodology for Open Pit Slope Design in Karst-Prone Ground Conditions Based on Integrated Stochastic-Limit Equilibrium Analysis

    Science.gov (United States)

    Zhang, Ke; Cao, Ping; Ma, Guowei; Fan, Wenchen; Meng, Jingjing; Li, Kaihui

    2016-07-01

    Using the Chengmenshan Copper Mine as a case study, a new methodology for open pit slope design in karst-prone ground conditions is presented based on integrated stochastic-limit equilibrium analysis. The numerical modeling and optimization design procedure contain a collection of drill core data, karst cave stochastic model generation, SLIDE simulation and bisection method optimization. Borehole investigations are performed, and the statistical result shows that the length of the karst cave fits a negative exponential distribution model, but the length of carbonatite does not exactly follow any standard distribution. The inverse transform method and acceptance-rejection method are used to reproduce the length of the karst cave and carbonatite, respectively. A code for karst cave stochastic model generation, named KCSMG, is developed. The stability of the rock slope with the karst cave stochastic model is analyzed by combining the KCSMG code and the SLIDE program. This approach is then applied to study the effect of the karst cave on the stability of the open pit slope, and a procedure to optimize the open pit slope angle is presented.

  20. Development of Landscape Architecture through Geo-eco-tourism in Tropical Karst Area to Avoid Extractive Cement Industry for Dignified and Sustainable Environment and Life

    Science.gov (United States)

    Cahyanti, Pita A. B.; Agus, Cahyono

    2017-08-01

    Karst areas in Indonesia amounted to 154,000 km2, potentially for extractive cement and wall paint industries. Exploitation of karst caused serious problems on the environment, health and social culture of the local community. Even though, karst region as a natural and cultural world heritage also have potential environmental services such as water resources, carbon sink, biodiversity, unique landscapes, natural caves, natural attractions, archaeological sites and mystic areas. Landscape architectural management of in the concept of blue revolution through the empowerment of land resources (soil, water, minerals) and biological resources (plant, animal, human), not only have adding value of economy aspect but also our dignified and sustainable environment and life through health, environmental, social, cultural, technological and management aspects. Geo-eco-tourism offers the efficiency of investment, increased creative innovation, increased funding, job creation, social capital development, stimulation of the socio-entrepreneurship in community. Community based geo-eco-tourism in Gunung Kidul Yogyakarta rapidly growing lately due to the local government banned the exploitation of karst. Landscape architecture at the caves, white sand beaches, cliffs in karst areas that beautiful, artistic and have special rare natural architecture form of stalactite and stalagmite, become the new phenomenal interested object of geo-eco-tourism. Many hidden nature objects that had been deserted and creepy could be visited by many local and foreign tourists. Landscape architectural management on hilltops with a wide view of the universe and fresh, sunset and sunrise, the clouds country are a rare sight for modern community. Local cultural attractions, local culinary, home stay with local communities will be an added attraction, but the infrastructure and human resources should be developed. Traveler photographs that widespread rapidly through social media and mass media became a

  1. Pilot project 'Karst water Dachstein'. Vol. 2: karst hydrology and contamination risk in springs

    International Nuclear Information System (INIS)

    Scheidleder, A.; Mandl, G.W.; Boroviczeny, F.; Hofmann, T.; Schubert, G.; Trimborn, P.; Stichler, W.; Graf, W.

    2001-01-01

    The pilot project 'Karstwasser Dachstein' aimed to ascertain the karst groundwater quality of one of the largest karst massifs in Austria, to examine and quantity the factors influencing karst groundwater quality and to gain experience in the monitoring of karst groundwater quality (Austrian Water Quality Monitoring System). The first phase of the pilot project examined comprehensively the factors influencing and the potential threats endangering karst water quality and was finished in 1994 with Vol. 1 entitled 'Karstwasserqualitaet' (HERLICSKA and LORBEER). The present study is based on the findings of the first phase of the project and aims to combine, analyze and assess the extensive quantity of data material with, special emphasis on karst hydrology and the contamination risk in springs. The interdisciplinary data analysis and the hydrogeological interpretation were carried out by the Austrian Federal Environment Agency (UBA), the Geological Survey of Austria (GBA) and the National Research Centre for Environment and Health (GSF). Their work was based on the detailed description of the geological conditions in the Dachstein area, on the thorough examination of chemical and physical spring water parameters, an isotope analyses of precipitation and spring waters as well as on the results of several tracer experiments and an investigations of the potential impacts of human activities. Investigations of the bacteriological contamination of the spring waters showed that there were only 6 out of 42 springs where there was no evidence of coliform bacteria or faecal germs. These 6 springs are all situated in the southern part of the Dachstein massif. For the analyses carried out to determine the content of chlorinated hydrocarbons, detection limits had been set very low. In all springs, evidence of chlorinated hydrocarbons was found at least once. These concentrations were all below the maximum allowable concentrations set out in the Groundwater Threshold Value

  2. Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars

    Science.gov (United States)

    McLennan, S.M.; Bell, J.F.; Calvin, W.M.; Christensen, P.R.; Clark, B. C.; de Souza, P.A.; Farmer, J.; Farrand, W. H.; Fike, D.A.; Gellert, Ralf; Ghosh, A.; Glotch, T.D.; Grotzinger, J.P.; Hahn, B.; Herkenhoff, K. E.; Hurowitz, J.A.; Johnson, J. R.; Johnson, S.S.; Jolliff, B.; Klingelhofer, G.; Knoll, A.H.; Learner, Z.; Malin, M.C.; McSween, H.Y.; Pocock, J.; Ruff, S.W.; Soderblom, L.A.; Squyres, S. W.; Tosca, N.J.; Watters, W.A.; Wyatt, M.B.; Yen, A.

    2005-01-01

    Impure reworked evaporitic sandstones, preserved on Meridiani Planum, Mars, are mixtures of roughly equal amounts of altered siliciclastic debris, of basaltic provenance (40 ?? 10% by mass), and chemical constituents, dominated by evaporitic minerals (jarosite, Mg-, Ca-sulfates ?? chlorides ?? Fe-, Na-sulfates), hematite and possibly secondary silica (60 ?? 10%). These chemical constituents and their relative abundances are not an equilibrium evaporite assemblage and to a substantial degree have been reworked by aeolian and subaqueous transport. Ultimately they formed by evaporation of acidic waters derived from interaction with olivine-bearing basalts and subsequent diagenetic alteration. The rocks experienced an extended diagenetic history, with at least two and up to four distinct episodes of cementation, including stratigraphically restricted zones of recrystallization and secondary porosity, non-randomly distributed, highly spherical millimeter-scale hematitic concretions, millimeter-scale crystal molds, interpreted to have resulted from dissolution of a highly soluble evaporite mineral, elongate to sheet-like vugs and evidence for minor synsedimentary deformation (convolute and contorted bedding, possible teepee structures or salt ridge features). Other features that may be diagenetic, but more likely are associated with relatively recent meteorite impact, are meter-scale fracture patterns, veins and polygonal fractures on rock surfaces that cut across bedding. Crystallization of minerals that originally filled the molds, early cement and sediment deformation occurred syndepositionally or during early diagenesis. All other diagenetic features are consistent with formation during later diagenesis in the phreatic (fluid saturated) zone or capillary fringe of a groundwater table under near isotropic hydrological conditions such as those expected during periodic groundwater recharge. Textural evidence suggests that rapidly formed hematitic concretions post

  3. East Chestnut Ridge hydrogeologic characterization: A geophysical study of two karst features

    International Nuclear Information System (INIS)

    1991-01-01

    Permitting and site selection activities for the proposed East Chestnut Ridge landfill, located on the Oak Ridge Reservation, have required additional hydrogeologic studies of two karst features. Geophysical testing methods were utilized for investigating these karst features. The objectives of the geophysical testing was to determine the feasibility of geophysical techniques for locating subsurface karst features and to determine if subsurface anomalies exist at the proposed landfill site. Two karst features, one lacking surface expression (sinkhole) but with a known solution cavity at depth (from previous hydrologic studies), and the other with surface expression were tested with surface geophysical methods. Four geophysical profiles, two crossing and centered over each karst feature were collected using both gravimetric and electrical resistivity techniques

  4. Isotopic and hydrogeochemical characterization of high-altitude karst aquifers in complex geological settings. The Ordesa and Monte Perdido National Park (Northern Spain) case study

    Energy Technology Data Exchange (ETDEWEB)

    Lambán, L.J., E-mail: javier.lamban@igme.es [Geological Survey of Spain (IGME) (Spain); Jódar, J., E-mail: jorge.jodar@upc.edu [Department of Geotechnical Engineering and Geosciences, Technical University of Catalonia (UPC), Barcelona (Spain); Custodio, E., E-mail: emilio.custodio@upc.edu [Department of Geotechnical Engineering and Geosciences, Technical University of Catalonia (UPC), Barcelona (Spain); Soler, A., E-mail: albertsoler@ub.edu [Grup de Mineralogia Aplicada i Medi Ambient, Departament Cristal lografia Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB) (Spain); Sapriza, G., E-mail: g.sapriza@usask.ca [Global Institute for Water Security, National Hydrology Research Centre (Canada); Soto, R., E-mail: r.soto@igme.es [Geological Survey of Spain (IGME) (Spain)

    2015-02-15

    The Ordesa and Monte Perdido National Park, located in the Southern Pyrenees, constitutes the highest karst system in Western Europe. No previous studies regarding its geochemical and isotopic groundwater characterization are available in this area. This work presents the results of field and sampling campaigns carried out between July 2007 and September 2013. The groundwater presents high calcium bicarbonate contents due to the occurrence of upper Cretaceous and lower Paleocene–Eocene carbonate materials in the studied area. Other relevant processes include dissolution of anhydrite and/or gypsum and incongruent dissolution of Mg-limestone and dolomite. The water stable isotopes (δ{sup 18}O, δ{sup 2}H) show that the oceanic fronts from the Atlantic Ocean are responsible for the high levels of precipitation. In autumn, winter, and spring, a deuterium excess is found in the recharge water, which could be related to local atmospheric transport of low-altitude snow sublimation vapour and its later condensation on the snow surface at higher altitude, where recharge is mostly produced. The recharge zones are mainly between 2500 m and 3200 m a.s.l. The tritium content of the water suggests short groundwater transit times. The isotopic composition of dissolved sulphate points to the existence of regional fluxes mixed with local discharge in some of the springs. This work highlights the major role played by the altitude difference between the recharge and discharge zones in controlling the chemistry and the vertical variability of the isotopic composition in high-altitude karst aquifers. - Highlights: • Environmental tracers are essential to study complex alpine karst aquifers. • The long presence of snow controls the deuterium excess in groundwater. • Seasonal δD content in springs depends on gap between recharge and discharge points. • The first hydrogeological characterization of the Ordesa National Park is presented. • Sulphate content in springs comes

  5. Tietkens Plain karst - Maralinga

    International Nuclear Information System (INIS)

    James, J.M.

    1988-09-01

    The Tietkens Plain karst is located to the north of Maralinga village which is on the crest of the Ooldea Range on the north and east margin of the Nullarbor Plain in western South Australia. The geology of the carbonate rocks in the Maralinga area is summarised. On Tietkens Plain from 1955 to 1963 nuclear weapons tests dispersed radioactive materials over the Maralinga area. Six nuclear devices were detonated in the air and one was exploded a few metres below the surface. The effect such explosions have on the karst and the possible rate of recovery of its surface are discussed. This report is the record of a visit to the Maralinga area from the 15th -21st November 1986 which involved an inspection of the karst surface together with collection of water, soil and rock samples. Results of the measurements made in order to assess water quality and water contamination by radioactive nuclides are presented. The implications arising from the presence of radioactive materials on the surface and the possibility of their entering and contaminating the groundwater in the area are discussed in the context of the chemistry of uranium and plutonium. The potential for transmission of contaminants through groundwater conduits and aquifers in the dolomite is discussed. Evidence is produced to show that the caves of the Nullabor Plain are not contaminated at present and are unlikely to be so in the future. 21 refs., 2 figs. 3 tabs., ills

  6. A glossary of Karst terminology

    Science.gov (United States)

    Monroe, Watson Hiner

    1970-01-01

    This glossary includes most terms used in describing karst geomorphologic features and processes. The terms are primarily those used in the literature of English-speaking countries, but a few of the more common terms in French, German, and Spanish are included, with references to the corresponding English terms where they are available. The glossary also includes simple definitions of the more common rocks and minerals found in karst terrain, common terms of hydrology, and a number of the descriptive terms used by speleologists. The glossary does not include definitions of most biospeleological terms, geologic structure terms, varieties of carbonate rock that require microscopic techniques for identification, or names describing tools and techniques of cave exploration.

  7. TEAM Science Advances STEM through Experiential Learning about Karst Geology at the Ozark Underground Laboratory.

    Science.gov (United States)

    Haskins, M. F.; Patterson, J. D.; Ruckman, B.; Keith, N.; Aley, C.; Aley, T.

    2017-12-01

    Carbonate karst represents approximately 14% of the world's land area and 20-25% of the land area in the United States. Most people do not understand this three dimensional landscape because they lack direct experience with this complicated geology. For the last 50 years, Ozark Underground Laboratory (OUL), located in Protem, MO, has been a pioneer in the research of karst geology and its influence on groundwater. OUL has also provided surface and sub-surface immersion experiences to over 40,000 individuals including students, educators, and Department of Transportation officials helping those individuals better understand the challenges associated with karst. Rockhurst University has incorporated OUL field trips into their educational programming for the last 30 years, thus facilitating individual understanding of karst geology which comprises approximately 60% of the state. Technology and Educators Advancing Missouri Science (TEAM Science) is a grant-funded professional development institute offered through Rockhurst University. The institute includes an immersion experience at OUL enabling in-service teachers to better understand natural systems, the interplay between the surface, sub-surface, and cave fauna, as well as groundwater and energy dynamics of karst ecosystems. Educating elementary teachers about land formations is especially important because elementary teachers play a foundational role in developing students' interest and aptitude in STEM content areas. (Funding provided by the U.S. Department of Education's Math-Science Partnership Program through the Missouri Department of Elementary and Secondary Education.)

  8. Visible and near-infrared (0.4-2.5 μm) reflectance spectra of playa evaporite minerals

    Science.gov (United States)

    Crowley, James K.

    1991-01-01

    Visible and near-infrared (VNIR; 0.4–2.4 μm) reflectance spectra were recorded for 35 saline minerals that represent the wide range of mineral and brine chemical compositions found in playa evaporite settings. The spectra show that many of the saline minerals exhibit diagnostic near-infrared absorption bands, chiefly attributable to vibrations of hydrogen-bonded structural water molecules. VNIR reflectance spectra can be used to detect minor hydrate phases present in mixtures dominated by anhydrous halite or thenardite, and therefore will be useful in combination with X ray diffraction data for characterizing natural saline mineral assemblages. In addition, VNIR reflectance spectra are sensitive to differences in sample hydration state and should facilitate in situ studies of minerals that occur as fragile, transitory dehydration products in natural salt crusts. The use of spectral reflectance measurements in playa studies should aid in mapping evaporite mineral distributions and may provide insight into the geochemical and hydrological controls on playa mineral and brine development.

  9. Response of the Karst Phreatic Zone to Flood Events in a Major River (Bohemian Karst, Czech Republic) and its Implication for Cave Genesis

    Czech Academy of Sciences Publication Activity Database

    Vysoká, H.; Bruthans, J.; Žák, Karel; Mls, J.

    2012-01-01

    Roč. 74, č. 1 (2012), s. 65-81 ISSN 1090-6924 R&D Projects: GA ČR GAP210/10/1760 Institutional research plan: CEZ:AV0Z30130516 Keywords : karst * cave genesis * Bohemian Karst Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.474, year: 2012

  10. Submerged Humid Tropical Karst Landforms Observed By High-Resolution Multibeam Survey in Nagura Bay, Ishigaki Island, Southwestern Japan

    Science.gov (United States)

    Kan, H.; Urata, K.; Nagao, M.; Hori, N.; Fujita, K.; Yokoyama, Y.; Nakashima, Y.; Ohashi, T.; Goto, K.; Suzuki, A.

    2014-12-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the South Ryukyu Islands, Japan. This is the first description of submerged humid tropical karst using multibeam bathymetry. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results with a grid size of 1 m over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. We assume that Nagura Bay was a large karst basin in which older limestone remained submerged, thus preventing corrosion and the accumulation of reef sediments during periods of submersion, whereas the limestone outcropping on land was corroded during multiple interglacial and glacial periods. Based on our bathymetric result together with aerial photographs of the coastal area, we conclude that the submerged karst landscape has likely developed throughout the whole of Nagura Bay, covering an area of ~6 × 5 km. Accordingly, this area hosts the largest submerged karst in Japan. We also observed abundant coral communities during our SCUBA observations. The present marine conditions of Nagura Bay are characterized by low energy (calm sea) and low irradiance owing to the terrestrial influence. Such conditions have been emphasized by the presence of large undulating landforms, which cause decreases in wave intensity and irradiance with depth. These characteristics have acted to establish unique conditions compared to other coral reef areas in the Ryukyu Islands. It may play an important role in supporting the regional coral reef ecosystem.

  11. Drilling through the Messinian evaporites: the beginning of a new adventure?

    Science.gov (United States)

    Bassetti, M. A.; Lofi, J.

    2009-04-01

    The sensitivity of past environments tell us a lot about the nature of changes, either of climatic or geodynamic origin. In this respect, the Mediterranean basin represents the ideal natural laboratory for studying the interaction between deep processes, tectonics, sedimentary fluxes and sea-level oscillation that are at the origin of the sedimentary records. A spectacular example of reactivity of this system have been experienced less than 6 Myrs ago, when the pan-Mediterranean realm underwent rapid and abrupt changes of paleo-environmental parameters that led to the well known Messinian Salinity Crisis (MSC, Hsü et al., 1973). This short-term event at the geological scale (~5.96-5.32 Ma) results from the progressive closure of the two-way connection between the Atlantic Ocean and the Mediterranean Sea. The most important characteristics of this event are: (1) a reduction of the Atlantic water supply having as a consequence, an increased salinity and in the precipitation of thick evaporites within shallow water marginal basins (presently disconnected from the deep basins); (2) a subsequent major sea-level fall exceeding 2000 m and resulting in the massive erosion of the margins and the development of deep subaerial canyons; (3) the accumulation of the product of the erosion in the downslope domain of the margins; (4) the deposition of thick evaporites (up to 3000 m thick) above the deep Mediterranean abyssal plains and (5) and a very rapid refilling of the Mediterranean basin during the Latest Miocene/Lower Pliocene, following the re-connection between Atlantic and Mediterranean through the Gibraltar straight. Timing, causes and chronology of the MSC are not yet fully understood, but different scenarii have been proposed to explain in details the modalities of this catastrophic event. Certainly, the ongoing discussion about not fully conclusive interpretations are mainly linked to the fact that so far, only the deepest and buried Mediterranean basins might offer

  12. River-groundwater connectivity in a karst system, Wellington, New South Wales, Australia

    Science.gov (United States)

    Keshavarzi, Mohammadreza; Baker, Andy; Kelly, Bryce F. J.; Andersen, Martin S.

    2017-03-01

    The characterization of river-aquifer connectivity in karst environments is difficult due to the presence of conduits and caves. This work demonstrates how geophysical imaging combined with hydrogeological data can improve the conceptualization of surface-water and groundwater interactions in karst terrains. The objective of this study is to understand the association between the Bell River and karst-alluvial aquifer at Wellington, Australia. River and groundwater levels were continuously monitored, and electrical resistivity imaging and water quality surveys conducted. Two-dimensional resistivity imaging mapped the transition between the alluvium and karst. This is important for highlighting the proximity of the saturated alluvial sediments to the water-filled caves and conduits. In the unsaturated zone the resistivity imaging differentiated between air- and sediment-filled karst features, and in the saturated zone it mapped the location of possible water- and sediment-filled caves. Groundwater levels are dynamic and respond quickly to changes in the river stage, implying that there is a strong hydraulic connection, and that the river is losing and recharging the adjacent aquifer. Groundwater extractions (1,370 ML, megalitres, annually) from the alluvial aquifer can cause the groundwater level to fall by as much as 1.5 m in a year. However, when the Bell River flows after significant rainfall in the upper catchment, river-leakage rapidly recharges the alluvial and karst aquifers. This work demonstrates that in complex hydrogeological settings, the combined use of geophysical imaging, hydrograph analysis and geochemical measurements provide insights on the local karst hydrology and groundwater processes, which will enable better water-resource and karst management.

  13. Vegetation in karst terrain of southwestern China allocates more biomass to roots

    Science.gov (United States)

    Ni, J.; Luo, D. H.; Xia, J.; Zhang, Z. H.; Hu, G.

    2015-07-01

    In mountainous areas of southwestern China, especially Guizhou province, continuous, broadly distributed karst landscapes with harsh and fragile habitats often lead to land degradation. Research indicates that vegetation located in karst terrains has low aboveground biomass and land degradation that reduces vegetation biomass, but belowground biomass measurements are rarely reported. Using the soil pit method, we investigated the root biomass of karst vegetation in five land cover types: grassland, grass-scrub tussock, thorn-scrub shrubland, scrub-tree forest, and mixed evergreen and deciduous forest in Maolan, southern Guizhou province, growing in two different soil-rich and rock-dominated habitats. The results show that roots in karst vegetation, especially the coarse roots, and roots in rocky habitats are mostly distributed in the topsoil layers (89 % on the surface up to 20 cm depth). The total root biomass in all habitats of all vegetation degradation periods is 18.77 Mg ha-1, in which roots in rocky habitat have higher biomass than in earthy habitat, and coarse root biomass is larger than medium and fine root biomass. The root biomass of mixed evergreen and deciduous forest in karst habitat (35.83 Mg ha-1) is not greater than that of most typical, non-karst evergreen broad-leaved forests in subtropical regions of China, but the ratio of root to aboveground biomass in karst forest (0.37) is significantly greater than the mean ratio (0.26 ± 0.07) of subtropical evergreen forests. Vegetation restoration in degraded karst terrain will significantly increase the belowground carbon stock, forming a potential regional carbon sink.

  14. EVAPORITE MICROBIAL FILMS, MATS, MICROBIALITES AND STROMATOLITES

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Penny Morris, P; Garriet Smith, G

    2008-01-28

    Evaporitic environments are found in a variety of depositional environments as early as the Archean. The depositional settings, microbial community and mineralogical composition vary significantly as no two settings are identical. The common thread linking all of the settings is that evaporation exceeds precipitation resulting in elevated concentrations of cations and anions that are higher than in oceanic systems. The Dead Sea and Storrs Lake are examples of two diverse modern evaporitic settings as the former is below sea level and the latter is a coastal lake on an island in the Caribbean. Each system varies in water chemistry as the Dead Sea dissolved ions originate from surface weathered materials, springs, and aquifers while Storrs Lake dissolved ion concentration is primarily derived from sea water. Consequently some of the ions, i.e., Sr, Ba are found at significantly lower concentrations in Storrs Lake than in the Dead Sea. The origin of the dissolved ions are ultimately responsible for the pH of each system, alkaline versus mildly acidic. Each system exhibits unique biogeochemical properties as the extreme environments select certain microorganisms. Storrs Lake possesses significant biofilms and stromatolitic deposits and the alkalinity varies depending on rainfall and storm activity. The microbial community Storrs Lake is much more diverse and active than those observed in the Dead Sea. The Dead Sea waters are mildly acidic, lack stromatolites, and possess a lower density of microbial populations. The general absence of microbial and biofilm fossilization is due to the depletion of HCO{sub 3} and slightly acidic pH.

  15. A model of karst systems of the Usturt plateau (Middle Asia); Un modelo de sistemas karsticos de la meseta Usturt (Asia central)

    Energy Technology Data Exchange (ETDEWEB)

    Victorov, A. S.

    2016-07-01

    The issues relating to the structure and development of desert karst is currently one of the least studied problems. The goal of the research efforts presented in this paper was to create a model of karst systems in the Usturt Plateau and, primarily, of the systems formed by the prevailing numerous surface karst landforms. The model is based on the following main assumptions: the process of emergence of the karst phenomena is probabilistic and occurs independently at non-intersecting sites; the probability of emergence of one depression at a reference site depends only on its area. The increase of the dimensions of a karst landform is a random process that occurs independently of other karst landforms, its speed is governed by random factors, and it is directly proportionate to the existing dimensions of the landform. The model does not assume constancy of climatic characteristics. The testing was conducted at several reference sites of the Usturt Plateau. The research allowed us to reach the following conclusions: the karst depressions of the Usturt Plateau, which are the typical forms of desert karst, are governed by the Poisson distribution of their centres and by the lognormal distribution of their dimensions, similar to the karst depressions in a humid climate. The results may be used in assessments of karst hazard for linear and areal structures, as well as for small-dimensional structures. (Author)

  16. Inventory of karst subsidence in the Valley and Ridge Province of East Tennessee

    International Nuclear Information System (INIS)

    Ketelle, R.H.; Newton, J.G.

    1986-01-01

    The first regional inventory of karst activity in the Valley and Ridge Province of East Tennessee was performed as a part of ongoing studies at Oak Ridge National Laboratory pertaining to environmental impact assessment of waste disposal in karst settings. More than half the land area in the Valley and Ridge Province of East Tennessee is underlain by karst-prone carbonate bedrock. The regional karst inventory was initiated to obtain current information on the extent of active karst subsidence in the region for use in decision making by the Department of Energy in planning future waste disposal facilities at Oak Ridge, Tennessee. The inventory was performed by contacting personnel of federal, state, and county agencies to obtain reports of known active karst subsidence within the region. Data from these interviews were tabulated resulting in identificaton of more than 250 karst subsidence incidents in East Tennessee, most of which have occurred since 1980. Although the infomation obtained was largely anecdotal, approximate location, date, size, and circumstances under which the collapses occurred were recorded for as many cases as could be documented. The study also included detailed reconnaissance of selected areas similar in geology and hydrology to a study area at Oak Ridge, Tennessee to identify causative factors which contribute to karst subsidence in the region and for comparison of the occurrence of visible karst features at different sites. Human activities affecting site hydrology such as large scale land clearing and earthmoving projects were related to most of the subsidence incidents inventoried

  17. Determination of karst collapse intensity indicator in area of nuclear power plant construction using incomplete data

    International Nuclear Information System (INIS)

    Sharapov, R

    2014-01-01

    The paper deals with the definition of karst collapse intensity. The technique for determining the intensity of karst formation and collapse on the basis of calculation and probabilistic method is given. Karst collapse formation is affected by a great variety of natural and anthropogenic factors. Each factor can vary quite widely. The paper describes a technique for determining karst collapse intensity from incomplete data. It uses karst processes monitoring data in the area and monitoring data of areas with similar values of the most significant factors leading to the karst collapses. The method used for determination of karst collapse intensity indicator in area of Nizhny Novgorod nuclear power plant construction

  18. Quantitative Analysis of Karst Conduit Structure Parameters and Hydraulic Parameters Based on Tracer Test

    Science.gov (United States)

    Qiang, Z.; Zhiqiang, Z.; Xu, M.; Jinyu, S.; Jihong, Q.

    2017-12-01

    The Old Town of Lijiang is famous as the world cultural heritage since 1997, while characterized by its ancient buildings and natural scenery, water is the soul of the town. Around Heilongtan Springs, there are a large quantity of springs at the Old Town of Lijiang , which is an important part of the World Cultural Heritage. Heilongtan Springs is 2420m above the sea level, the annual variation of the flow rate varies greatly (0 8042 x 104 m3 / year). Recharge area Jiuzihai depressions is 6km long, 3km wide and 2800m above sea level, as main karst water recharge area karst funnel and the sink hole are developing on this planation surface, in the research area medium to thick layers of limestone made up Beiya formation (T2b) of Triassic system distributed widely, karst is strongly developed and the fissure caves water occurrence. In order to exploring the application of tracer test in karst hydrogeology, a tracer test was conducted from Jiuzihai depressions to Ganze Spring. Based on the hydrogeological conditions in the study area, tracer test was used for analysis of groundwater connectivity and flow field characteristics, quantitative analysis of Tracer Breakthrough Curves (BTC) with code Qtracer2. The results demonstated that there are hydraulic connection between Jiuzihai depressions with Ganze Spring, and there are other karst conduits in this area. The longitudinal dispersivity coefficient is 0.24 m2/s, longitudinal dispersivity is 12.06m, flow-channel volume is 3.08×104 m3, flow-channel surface area is 3.27×107m2, mean diameter is 1.42m, Reynolds number is 25187, Froude number is 0.0061, respectively. The groundwater in this area is in a slow turbulent state. The results are of great significance to understand the law of groundwater migration, establish groundwater quality prediction model and exploit karst water resources effectively.

  19. [Characteristic of ammonia nitrogen adsorption on karst underground river sediments].

    Science.gov (United States)

    Guo, Fang; Chen, Kun-Kun; Jiang, Guang-Hui

    2011-02-01

    Karst aquifers are one of the most important aquifers in Southwestern China. One of the characteristics of karst aquifers is the enhanced permeability permits high flow velocities are capable of transporting suspended and bedload sediments. Mobile sediment in karst may act as a vector for the transport of contaminates. 14 sediment samples were collected from two underground rivers in two typical karst areas in Liuzhou city, Guangxi Autonomous Region, China. According to simulated experiment methods, characteristic of adsorption of ammonia nitrogen on sediment was studied. The results of ammonia nitrogen adsorption dynamics on sediments showed that the maximum adsorption velocity was less than 2 h. The adsorption balance quantity in 5 h accounted for 71% - 98% of the maximum adsorption quantity. The maximum adsorption quantity of ammonia nitrogen was 385.5 mg/kg, which was sediment from a cave in the middle areas of Guancun underground river system. The study of isotherm adsorption indicated adsorption quantity of NH4+ increase followed by incremental balance concentration of NH4+ in the aquatic phase. Adsorption quantity of ammonia nitrogen in sediments has a relative linear relationship with adsorption balance concentrations. Adsorption-desorption balance concentrations were all low, indicating sediments from underground rivers have great adsorption potential. Under the condition of low and high concentrations of ammonia nitrogen in overlying water, Langmuir and Tempkin couldn't simulate or simulate results couldn't reach remarkable level, whilst Linear and Freundlich models could simulate well. Research on different type sediments, sampling times and depths from two underground rivers shows characteristic of ammonia nitrogen adsorption on karst underground river sediments doesn't have good correspondence with the type of sediments. One of the reasons is there is no big difference between sediments in the development of climate, geology, hydrological conditions

  20. Main karst and caves of Switzerland; El karst y las cuevas mas importantes de Suiza

    Energy Technology Data Exchange (ETDEWEB)

    Jeannin, P. Y.

    2016-07-01

    This paper presents an overview of the main karst areas and cave systems in Switzerland. The first part encloses descriptions of the main geological units that hold karst and caves in the country and summarizes a brief history of research and protection of the cave environments. The second part presents three regions enclosing large cave systems. Two regions in the Alps enclose some of the largest limestone caves in Europe: Siebenhengste (Siebenhengste cave system with ∼160 km and Barenschacht with 70 km) and Bodmeren-Silberen (Holloch cave system with 200 km and Silberen System with 39 km). These systems are also among the deepest with depths ranging between 880 and 1340 m. The third example is from the Jura Mountains (northern Switzerland). (Author)

  1. Karst in Wadi Bani Khalid, Oman

    Science.gov (United States)

    Abdelaziz, Ramadan

    2017-04-01

    There are several important in Oman. The main aquifer is surficial aquifer and fractured rocks. In fact, the geology of Oman is complex whichmake the hydraulic continuity of bedrock is limited and formaing localized aquifers. caves in Oman are varying types and length, size and geographic formations. Many caves and valleys founded in Oman. Wadi Bani Khalid hosts complex network of fractured rock. Karst in Wadi Bani Kalid made upof Limestone(Calcium, which is dissolve in water.A rain water pass through the rock it is erode the rock and form caves. The cave located in Miqil. The karst was formed in Calcium Carbonate rocks.

  2. Hydrograph monitoring and analysis for sustainable karst water management in Nyadeng Spring, East Borneo

    Science.gov (United States)

    Widyastuti, M.; Fatchurohman, H.; Fathoni, W. A.; Hakim, A. A.; Haryono, E.

    2018-04-01

    Karst aquifer stores abundant water resources within its matrix, conduits, and intergranular pores. Karst aquifer plays an important role in providing water supply, especially in the areas nearby that commonly dry and lack of surface water resources. Karst spring hydrograph analysis is very fundamental step to–assess and determines the condition of the catchment area in karst terrain. Recession curve is believed to be the most stable part in single flood hydrograph that represents the aquifer characteristics. Nyadeng is one of the most significant karst springs that located in Merabu Karst Area, East Borneo. Villagers in Merabu highly depend on Nyadeng Spring for fulfilled their freshwater need. Hydrograph monitoring has been initiated for one year in Nyadeng Spring as a preliminary action for karst water management in Merabu. Water level data series obtained using automatic water level data logger and then correlated with manual discharge measurement to generate stage-discharge rating curve. The stage-discharge rating curve formula for Nyadeng Spring calculated as y = 0,0102e5,8547x with r2 value = 0.8759. From the combination of several single flood events, Master Recession Curve (MRC) was generated to determine flow regime as the main consideration for karstification degree calculation. From the MRC result, flow regimes formula determined as Qt = 3.2-0.001t + 1.2(1-0.012t)+1.6(1-0.035t) indicated that one sub-regime with laminar flow and two sub-regimes with turbulent flow existed. From the MRC formula, the degree of karstification in Nyadeng Spring classified at seventh scale (developed karstification of the aquifer) based on Malik’s karstification degree (2012). The degree of karstification in Nyadeng Spring indicates that the aquifer formed by large conduit channels, fissures, and macro fissures which are able to provide significant water sources that can be utilized for multi purposes. Therefore, it is concluded that spring hydrograph monitoring provide

  3. Physical and Hydrological Meaning of the Spectral Information from Hydrodynamic Signals at Karst Springs

    Science.gov (United States)

    Dufoyer, A.; Lecoq, N.; Massei, N.; Marechal, J. C.

    2017-12-01

    Physics-based modeling of karst systems remains almost impossible without enough accurate information about the inner physical characteristics. Usually, the only available hydrodynamic information is the flow rate at the karst outlet. Numerous works in the past decades have used and proven the usefulness of time-series analysis and spectral techniques applied to spring flow, precipitations or even physico-chemical parameters, for interpreting karst hydrological functioning. However, identifying or interpreting the karst systems physical features that control statistical or spectral characteristics of spring flow variations is still challenging, not to say sometimes controversial. The main objective of this work is to determine how the statistical and spectral characteristics of the hydrodynamic signal at karst springs can be related to inner physical and hydraulic properties. In order to address this issue, we undertake an empirical approach based on the use of both distributed and physics-based models, and on synthetic systems responses. The first step of the research is to conduct a sensitivity analysis of time-series/spectral methods to karst hydraulic and physical properties. For this purpose, forward modeling of flow through several simple, constrained and synthetic cases in response to precipitations is undertaken. It allows us to quantify how the statistical and spectral characteristics of flow at the outlet are sensitive to changes (i) in conduit geometries, and (ii) in hydraulic parameters of the system (matrix/conduit exchange rate, matrix hydraulic conductivity and storativity). The flow differential equations resolved by MARTHE, a computer code developed by the BRGM, allows karst conduits modeling. From signal processing on simulated spring responses, we hope to determine if specific frequencies are always modified, thanks to Fourier series and multi-resolution analysis. We also hope to quantify which parameters are the most variable with auto

  4. Woodville Karst Plain, North Florida

    OpenAIRE

    2006-01-01

    Map showing the largest mapped underwater cave systems and conduit flow paths confirmed by tracer testing relative to surface streams, sinkholes and potentiometric surface of the Florida aquifer in the Woodville Karst Plain, Florida

  5. Hydrated Minerals and Evaporites as Key Targets for a Mars Sample Return Mission

    Science.gov (United States)

    Adeli, S.; Hauber, E.; Jaumann, R.

    2018-04-01

    Here we focus on hydrated minerals and evaporites as paleo-environment indicators with preservation capacity. Thus, samples from these materials would increase our knowledge about the past aqueous activities of Mars and its habitability potentials.

  6. Folk use of medicinal plants in Karst and Gorjanci, Slovenia.

    Science.gov (United States)

    Lumpert, Mateja; Kreft, Samo

    2017-02-23

    Information on the use of medicinal plants in Karst and Gorjanci is not available in the literature, but collection of plants is still an important and widespread practice in these regions. Karst and Gorjanci are two remote regions in Slovenia that are only 120 km apart but have different climates; one region is close to the Italian border, and the other is near the Croatian border. Our aim was to report and compare the use of medicinal plants in both regions. From October 2013 to September 2014, 25 informants each in Karst and Gorjanci were interviewed during field research. The age of the informants ranged from 33 to 89 years, with an average age of 61 years in Karst and 69 years in Gorjanci. The main question was "Which plants do or did you collect from nature and use?" Plants of medicinal, nutritive, veterinary or cosmetic use were considered. A total of 78 and 82 taxa were reported in Karst and Gorjanci, respectively; 65 taxa were reported in both regions. Approximately 64% of the plants in each region were distinctive for only a few informants (fewer than 7). The remaining plants were considered important, and the majority were mutual to both regions. Few reported plants were typical for just one region. Differences in the use of some common medicinal plants were observed, e.g., Matricaria chamomilla was used mostly for the treatment of gastrointestinal disorders, respiratory infections and sore eyes in Gorjanci but as a calmative in Karst. Altogether, 15 different oral and 15 different topical medicinal preparations were reported. Folk knowledge was found to be influenced by the media, particularly popular books about medicinal plants that were published in the 20th century. The present research documents the folk use of medicinal plants in Karst and Gorjanci, Slovenia. This rapidly changing practice needs to be documented before it disappears or changes.

  7. Improving Geologic and Engineering Models of Midcontinent Fracture and Karst-Modified Reservoirs Using New 3-D Seismic Attributes

    Energy Technology Data Exchange (ETDEWEB)

    Susan Nissen; Saibal Bhattacharya; W. Lynn Watney; John Doveton

    2009-03-31

    Our project goal was to develop innovative seismic-based workflows for the incremental recovery of oil from karst-modified reservoirs within the onshore continental United States. Specific project objectives were: (1) to calibrate new multi-trace seismic attributes (volumetric curvature, in particular) for improved imaging of karst-modified reservoirs, (2) to develop attribute-based, cost-effective workflows to better characterize karst-modified carbonate reservoirs and fracture systems, and (3) to improve accuracy and predictiveness of resulting geomodels and reservoir simulations. In order to develop our workflows and validate our techniques, we conducted integrated studies of five karst-modified reservoirs in west Texas, Colorado, and Kansas. Our studies show that 3-D seismic volumetric curvature attributes have the ability to re-veal previously unknown features or provide enhanced visibility of karst and fracture features compared with other seismic analysis methods. Using these attributes, we recognize collapse features, solution-enlarged fractures, and geomorphologies that appear to be related to mature, cockpit landscapes. In four of our reservoir studies, volumetric curvature attributes appear to delineate reservoir compartment boundaries that impact production. The presence of these compartment boundaries was corroborated by reservoir simulations in two of the study areas. Based on our study results, we conclude that volumetric curvature attributes are valuable tools for mapping compartment boundaries in fracture- and karst-modified reservoirs, and we propose a best practices workflow for incorporating these attributes into reservoir characterization. When properly calibrated with geological and production data, these attributes can be used to predict the locations and sizes of undrained reservoir compartments. Technology transfer of our project work has been accomplished through presentations at professional society meetings, peer-reviewed publications

  8. Karst aquifer characterization using geophysical remote sensing of dynamic recharge events

    Science.gov (United States)

    Grapenthin, R.; Bilek, S. L.; Luhmann, A. J.

    2017-12-01

    Geophysical monitoring techniques, long used to make significant advances in a wide range of deeper Earth science disciplines, are now being employed to track surficial processes such as landslide, glacier, and river flow. Karst aquifers are another important hydrologic resource that can benefit from geophysical remote sensing, as this monitoring allows for safe, noninvasive karst conduit measurements. Conduit networks are typically poorly constrained, let alone the processes that occur within them. Geophysical monitoring can also provide a regionally integrated analysis to characterize subsurface architecture and to understand the dynamics of flow and recharge processes in karst aquifers. Geophysical signals are likely produced by several processes during recharge events in karst aquifers. For example, pressure pulses occur when water enters conduits that are full of water, and experiments suggest seismic signals result from this process. Furthermore, increasing water pressure in conduits during recharge events increases the load applied to conduit walls, which deforms the surrounding rock to yield measureable surface displacements. Measureable deformation should also occur with mass loading, with subsidence and rebound signals associated with increases and decreases of water mass stored in the aquifer, respectively. Additionally, geophysical signals will likely arise with turbulent flow and pore pressure change in the rock surrounding conduits. Here we present seismic data collected during a pilot study of controlled and natural recharge events in a karst aquifer system near Bear Spring, near Eyota, MN, USA as well as preliminary model results regarding the processes described above. In addition, we will discuss an upcoming field campaign where we will use seismometers, tiltmeters, and GPS instruments to monitor for recharge-induced responses in a FL, USA karst system with existing cave maps, coupling these geophysical observations with hydrologic and

  9. Calculation of the Strip Foundation on Solid Elastic Base, Taking into Account the Karst Collapse

    Science.gov (United States)

    Sharapov, R.; Lodigina, N.

    2017-07-01

    Karst processes greatly complicate the construction and operation of buildings and structures. Due to the karstic deformations at different times there have been several major accidents, which analysis showed that in all cases the fundamental errors committed at different stages of building development: site selection, engineering survey, design, construction or operation of the facilities. Theory analysis of beams on elastic foundation is essential in building practice. Specialist engineering facilities often have to resort to multiple designing in finding efficient forms of construction of these facilities. In work the calculation of stresses in cross-sections of the strip foundation evenly distributed load in the event of karst. A comparison of extreme stress in the event of karst and without accounting for the strip foundation as a beam on an elastic foundation.

  10. Adapted hydropower-driven water supply system: assessment of an underground application in an Indonesian karst area

    Science.gov (United States)

    Oberle, P.; Ikhwan, M.; Stoffel, D.; Nestmann, F.

    2016-09-01

    Populated karst landscapes can be found all over the world, although their natural boundary conditions mostly lead to distinct challenges regarding a sustainable water supply. Especially in developing and emerging countries, this situation aggravates since appropriate technologies and water management concepts are rarely available. Against this background, the interdisciplinary, German-Indonesian joint project " Integrated Water Resources Management (IWRM) Indonesia", funded by the German Federal Ministry of Education and Research (BMBF), focused on the development and exemplary implementation of adapted techniques to remedy the partly severe water scarcity in the region Gunung Sewu. This karst area, widely known as " Java's poorhouse", is located on the southern coast of Java Island and distinctly suffers from the mentioned constraints. Under the aegis of the Karlsruhe Institute of Technology (KIT), the conceptual and technical achievements of the "IWRM Indonesia" joint research project are characterized by a high potential for multiplication not only for karst areas but also for non-karst regions. One of the project's major accomplishments is the erection of an innovative hydropower-driven water supply facility located in a karst cave 100 m below ground and continuously supplying tens of thousands of people with fresh water. Referring to the plant's innovative character and the demanding conditions on-site, the implementation was a highly iterative process leading to today's autonomous operation by an Indonesian public authority. Based on the experiences gained during design, construction, operation and monitoring phase, this paper introduces an implementation approach for adapted technologies as well as a comprising technical and economical assessment of the plant's operation.

  11. Isotopic hydrological studies carried out on the Karst water system

    International Nuclear Information System (INIS)

    Longinelli, A.

    1988-03-01

    The isotopic composition and temperature of many karst springs in the area of Trieste (Italy) have been measured for about three and a half years. During the same period the isotopic composition of precipitation has also been systematically studied. The isotopic composition of springs generally shows variations which are markedly shifted in time with respect to those of precipitation. In most of the springs the heavy isotope contents of winter samples are the highest of the whole year. On the contrary, summer samples normally show quite negative δ-values, the most negative of which often refer to the last summer months. The data obtained are explained in terms of variable mixing of waters from two main reservoirs. The less negative reservoir (in terms of δ) is recharged by ''local'' meteoric waters falling on the westernmost section of the karst area whose mean elevation is about 400 m a.s.l. The most negative reservoir is probably recharged by meteoric waters falling on the Slovenian section of the karst, whose mean elevation is about 800-900 m a.s.l. At least in the case of some of the northernmost karst springs, it is likely that a third water system, basically fed by the Isonzo river, flowing north of the karst area, could interfere with the previously mentioned reservoirs, partially controlling the outflow of some springs. 6 figs

  12. Projected land use changes impacts on water yields in the karst mountain areas of China

    Science.gov (United States)

    Lang, Yanqing; Song, Wei; Deng, Xiangzheng

    2018-04-01

    Human-induced land use changes over short time scales have significant impacts on water yield, especially in China because of the rapid social economic development. As the biggest developing country of the world, China's economy is expected to continuously grow with a high speed in the next few decades. Therefore, what kind of land use changes will occur in the future in China? How these changes will influence the water yields? To address this issue, we assessed the water yields in the karst mountain area of China during the periods of 1990-2010 and 2010-2030 by coupling an Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and a Conversion of Land Use and its Effects (CLUE) model. Three different land use scenarios i.e. natural growth, economic development, and ecological protection, were developed in 2030 using the CLUE model. It was concluded that, given land use changes between 1990 and 2010, total water yields in the karst mountain area are characterized by a trend towards fluctuating reduction. However, total water yields of 2030 in the economic development scenario revealed an increase of 1.25% compared to the actual water yields in 2010. The economy development in karst mountain areas of China in the future has a slight positive influence on water yields.

  13. Identification of karst sinkholes in a forested karst landscape using airborne laser scanning data and water flow analysis

    Science.gov (United States)

    Hofierka, Jaroslav; Gallay, Michal; Bandura, Peter; Šašak, Ján

    2018-05-01

    Karst sinkholes (dolines) play an important role in a karst landscape by controlling infiltration of surficial water, air flow or spatial distribution of solar energy. These landforms also present a limiting factor for human activities in agriculture or construction. Therefore, mapping such geomorphological forms is vital for appropriate landscape management and planning. There are several mapping techniques available; however, their applicability can be reduced in densely forested areas with poor accessibility and visibility of the landforms. In such conditions, airborne laser scanning (ALS) provides means for efficient and accurate mapping of both land and landscape canopy surfaces. Taking the benefits of ALS into account, we present an innovative method for identification and evaluation of karst sinkholes based on numerical water flow modelling. The suggested method was compared to traditional techniques for sinkhole mapping which use topographic maps and digital terrain modelling. The approach based on simulation of a rainfall event very closely matched the reference datasets derived by manual inspection of the ALS digital elevation model and field surveys. However, our process-based approach provides advantage of assessing the magnitude how sinkholes influence concentration of overland water flow during extreme rainfall events. This was performed by calculating the volume of water accumulated in sinkholes during the simulated rainfall. In this way, the influence of particular sinkholes on underground geomorphological systems can be assessed. The method was demonstrated in a case study of Slovak Karst in the West Carpathians where extreme rainfalls or snow-thaw events occur annually. We identified three spatially contiguous groups of sinkholes with a different effect on overland flow concentration. These results are discussed in relation to the known underground hydrological systems.

  14. The cost of karst subsidence and sinkhole collapse in the United States compared with other natural hazards

    Science.gov (United States)

    Weary, David J.

    2015-01-01

    Rocks with potential for karst formation are found in all 50 states. Damage due to karst subsidence and sinkhole collapse is a natural hazard of national scope. Repair of damage to buildings, highways, and other infrastructure represents a significant national cost. Sparse and incomplete data show that the average cost of karst-related damages in the United States over the last 15 years is estimated to be at least $300,000,000 per year and the actual total is probably much higher. This estimate is lower than the estimated annual costs for other natural hazards; flooding, hurricanes and cyclonic storms, tornadoes, landslides, earthquakes, or wildfires, all of which average over $1 billion per year. Very few state organizations track karst subsidence and sinkhole damage mitigation costs; none occurs at the Federal level. Many states discuss the karst hazard in their State hazard mitigation plans, but seldom include detailed reports of subsidence incidents or their mitigation costs. Most State highway departments do not differentiate karst subsidence or sinkhole collapse from other road repair costs. Amassing of these data would raise the estimated annual cost considerably. Information from insurance organizations about sinkhole damage claims and payouts is also not readily available. Currently there is no agency with a mandate for developing such data. If a more realistic estimate could be made, it would illuminate the national scope of this hazard and make comparison with costs of other natural hazards more realistic.

  15. Understanding karst environments by thermo-hygrometric monitoring: preliminary results from the Cesi Mountain karst system (Central Italy

    Directory of Open Access Journals (Sweden)

    Lucio Di Matteo

    2016-06-01

    Full Text Available The understanding of karst systems is of paramount importance for the protection and valorisation of these environments. A multidisciplinary study is presented to investigate the possible interconnection between karst features of a karst area located in the south-western part of the Martani chain (Cesi Mountain, Central Italy. This hydrogeological structure contributes to recharge a deep regional aquifer. The latter feeds the high discharge and salinity Stifone springs. In the southwestern part of Martani chain, seven caves have been mapped, five of which are hosted in the Calcare Massiccio Formation. The analysis of thermo-hygrometric data collected since Autumn 2014 into the caves and those from external meteorological stations, showed the timing of the airflow inversion occurring on late winter/early spring and summer/ early autumn. Despite the complexity of the morphology of caves and of conceptual models of airflow pattern, these data seem to indicate that the monitored small caves could be interconnected to a considerably wider cave system. Data here presented coupled with the knowledge on hydrogeological and geological-structural setting of the limestone massif are useful to drive future speleological explorations, aiming to discover new large cavities and to better understand the water recharge process.

  16. Subterranean karst environments as a global sink for atmospheric methane

    Science.gov (United States)

    Webster, Kevin D.; Drobniak, Agnieszka; Etiope, Giuseppe; Mastalerz, Maria; Sauer, Peter E.; Schimmelmann, Arndt

    2018-03-01

    The air in subterranean karst cavities is often depleted in methane (CH4) relative to the atmosphere. Karst is considered a potential sink for the atmospheric greenhouse gas CH4 because its subsurface drainage networks and solution-enlarged fractures facilitate atmospheric exchange. Karst landscapes cover about 14% of earth's continental surface, but observations of CH4 concentrations in cave air are limited to localized studies in Gibraltar, Spain, Indiana (USA), Vietnam, Australia, and by incomplete isotopic data. To test if karst is acting as a global CH4 sink, we measured the CH4 concentrations, δ13CCH4, and δ2HCH4 values of cave air from 33 caves in the USA and three caves in New Zealand. We also measured CO2 concentrations, δ13CCO2, and radon (Rn) concentrations to support CH4 data interpretation by assessing cave air residence times and mixing processes. Among these caves, 35 exhibited subatmospheric CH4 concentrations in at least one location compared to their local atmospheric backgrounds. CH4 concentrations, δ13CCH4, and δ2HCH4 values suggest that microbial methanotrophy within caves is the primary CH4 consumption mechanism. Only 5 locations from 3 caves showed elevated CH4 concentrations compared to the atmospheric background and could be ascribed to local CH4 sources from sewage and outgassing swamp water. Several associated δ13CCH4 and δ2HCH4 values point to carbonate reduction and acetate fermentation as biochemical pathways of limited methanogenesis in karst environments and suggest that these pathways occur in the environment over large spatial scales. Our data show that karst environments function as a global CH4 sink.

  17. 4D Monitoring of Active Sinkholes with a Terrestrial Laser Scanner (TLS: A Case Study in the Evaporite Karst of the Ebro Valley, NE Spain

    Directory of Open Access Journals (Sweden)

    Alfonso Benito-Calvo

    2018-04-01

    Full Text Available This work explores, for the first time, the application of a Terrestrial Laser Scanner (TLS and a comparison of point clouds in the 4D monitoring of active sinkholes. The approach is tested in three highly-active sinkholes related to the dissolution of salt-bearing evaporites overlain by unconsolidated alluvium. The sinkholes are located in urbanized areas and have caused severe damage to critical infrastructure (flood-control dike, a major highway. The 3D displacement models derived from the comparison of point clouds with exceptionally high spatial resolution allow complex spatial and temporal subsidence patterns within one of the sinkholes to be resolved. Detected changes in the subsidence activity (e.g., sinkhole expansion, translation of the maximum subsidence zone, development of incipient secondary collapses are related to potential controlling factors such as floods, water table changes or remedial measures. In contrast, with detailed mapping and high-precision leveling, the displacement models, covering a relatively short time span of around 6 months, do not capture the subtle subsidence (<0.6–1 cm that affects the marginal zones of the sinkholes, precluding precise mapping of the edges of the subsidence areas. However, the performance of TLS can be adversely affected by some methodological limitations and local conditions: (1 limited accuracy in large investigation areas that require the acquisition of a high number of scans, increasing the registration error; (2 surface changes unrelated to sinkhole activity (e.g., vegetation, loose material; (3 traffic-related vibrations and wind blast that affect the stability of the scanner.

  18. Impact of evaporite dissolution and collapse on highways and other cultural features in the Texas Panhandle and Eastern New Mexico

    International Nuclear Information System (INIS)

    Simpkins, W.W.; Gustavson, T.C.; Alhades, A.B.; Hoadley, A.D.

    1981-01-01

    Geological investigations in the Texas Panhandle and eastern New Mexico indicate that regional subsurface dissolution of Permian evaporites has occurred and is an ongoing process. Evidence of removal of large volumes of evaporites (mainly halite) and collapse of overlying beds is demonstrated by cross sections constructed from gamma-ray logs. Surface manifestation of subsurface dissolution and collapse is clearly shown in Hall County, Texas, where over 400 sinkholes and undrained depressions have been identified from aerial photographs. Sinkhole diameters up to approximately 100 m (300 ft) and depths to 15 m (50 ft) have been observed. Eleven active northeast- and southwest-trending fractures and faults have been recognizd, some of which are demonstrated as patched sections of highways. Formation of collapse features and faults that damage highways is a recognized problem in the region. Stock tanks and large reservors are also affected to a lesser degree. Dissolution and collapse pose difficult problems for geologists, highway engineers, and maintenance crews. Areas of active subsurface dissolution have been identified, but development of collapse features and faults at the surface generally follows no predictable pattern. The history of, and potential for, evaporite dissolution sould be investigated in each area before construction of highways, reservoirs, and stock tanks. Areas with high densities of collapse features, fractures, and faults should be avoided when possible

  19. Fracture characterization and discrimination criteria for karst and tectonic fractures in the Ellenburger Group, West Texas: Implications for reservoir and exploration models

    Energy Technology Data Exchange (ETDEWEB)

    Hoak, T.E. [Science Applications International Corp., Germantown, MD (United States)]|[Kestrel Geoscience, Littleton, CO (United States); Sundberg, K.R. [Phillips Petroleum Co., Bartlesville, OK (United States); Deyhim, P. [Oklahoma State Univ., Stillwater, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States). Lab. for Computational Geodynamics

    1998-12-31

    In the Ellenburger Group fractured dolomite reservoirs of West Texas, it is extremely difficult to distinguish between multiple phases of karst-related fracturing, modifications to the karst system during burial, and overprinting tectonic fractures. From the analyses of drill core, the authors developed criteria to distinguish between karst and tectonic fractures. In addition, they have applied these criteria within the context of a detailed diagenetic cement history that allows them to further refine the fracture genesis and chronology. In these analyses, the authors evaluated the relationships between fracture intensity, morphologic attributes, host lithology, fracture cement, and oil-staining. From this analysis, they have been able to characterize variations in Ellenburger tectonic fracture intensity by separating these fractures from karst-related features. In general, the majority of fracturing in the Ellenburger is caused by karst-related fracturing although a considerable percentage is caused by tectonism. These findings underscore the importance of considering the complete geologic evolution of a karst reservoir during exploration and field development programs. The authors have been able to more precisely define the spatial significance of the fracture data sets by use of oriented core from Andector Field. They have also demonstrated the importance of these results for exploration and reservoir development programs in West Texas, and the potential to extrapolate these results around the globe. Given the historic interest in the large hydrocarbon reserves in West Texas carbonate reservoirs, results of this study will have tremendous implications for exploration and production strategies targeting vuggy, fractured carbonate systems not only in West Texas, but throughout the globe.

  20. Characterizing fate and transport properties in karst aquifers under different hydrologic conditions

    Science.gov (United States)

    Rodriguez, E.; Padilla, I. Y.

    2017-12-01

    Karst landscapes contain very productive aquifers. The hydraulic and hydrogeological characteristics of karst aquifers make these systems capable of storing and transporting large amount of water, but also highly vulnerable to contamination. Their extremely heterogeneous nature prevents accurate prediction in contaminant fate and transport. Even more challenging is to understand the impact of hydrologic conditions changes on fate and transport processes. This studies aims at characterizing fate and transport processes in the karst groundwater system of northern Puerto Rico under different hydrologic conditions. The study involves injecting rhodamine and uranine dyes into a sinkhole, and monitoring concentrations at a spring. Results show incomplete recovery of tracers, but breaking curves can be used to estimate advective, dispersive and mass transfer characteristic of the karst system. Preliminary results suggest significant differences in fate and transport characteristics under different hydrologic conditions.

  1. Karst development and speleogenesis, Isla de Mona, Puerto Rico

    Science.gov (United States)

    Frank, E.F.; Mylroie, J.; Troester, J.; Alexander, E.C.; Carew, J.L.

    1998-01-01

    Isla de Mona consists of a raised table-top Miocene-Pliocene reef platform bounded on three sides by vertical cliffs, up to 80 m high. Hundreds of caves ring the periphery of the island and are preferentially developed in, but not limited to, the Lirio Limestone/Isla de Mona Dolomite contact. These flank margin caves originally formed at sea level and are now exposed at various levels by tectonic uplift of the island (Franbk 1983; Mylroie et al. 1995b). Wall cusps, a characteristic feature of flank margin caves, are ubiquitois features. Comparisons among similar caves formed in the Bahamas and Isla de Mona reveal the same overall morphology throughout the entire range of sizes and complexities. The coincidence of the primary cave development zone with the Lirio Limestone/Isla de Mona Dolomite contact may result from syngenetic speleogenesis and dolomitization rather than preferential dissolution along a lithologic boundary. Tectonic uplift and glacioeustatic sea level fluctuations produced caves at a variety of elevations. Speleothem dissolution took place in many caves under phreatic conditions, evidence these caves were flooded after an initial period of subaerial exposure and speleothem growth. Several features around the perimeter of the island are interpreted to be caves whose roofs were removed by surficial denudation processes. Several large closed depressions and dense pit cave fields are further evidence of surficial karst features. The cliff retreat around the island perimeter since the speleogenesis of the major cave systems is small based upon the distribution of the remnant cave sections.

  2. Eogenetic karst hydrology: insights from the 2004 hurricanes, peninsular Florida.

    Science.gov (United States)

    Florea, Lee J; Vacher, H L

    2007-01-01

    Eogenetic karst lies geographically and temporally close to the depositional environment of limestone in warm marine water at low latitude, in areas marked by midafternoon thunderstorms during a summer rainy season. Spring hydrographs from such an environment in north-central Florida are characterized by smooth, months-long, seasonal maxima. The passage of Hurricanes Frances and Jeanne in September 2004 over three field locations shows how the eogenetic karst of the Upper Floridan Aquifer responds to unequivocal recharge events. Hydrographs at wells in the High Springs area, Rainbow Springs, and at Morris, Briar, and Bat Caves all responded promptly with a similar drawn-out rise to a maximum that extended long into the winter dry season. The timing indicates that the typical hydrograph of eogenetic karst is not the short-term fluctuations of springs in epigenic, telogenetic karst, or the smoothed response to all the summer thunderstorms, but rather the protracted response of the system to rainfall that exceeds a threshold. The similarity of cave and noncave hydrographs indicates distributed autogenic recharge and a free communication between secondary porosity and permeable matrix-both of which differ from the hydrology of epigenic, telogenetic karst. At Briar Cave, drip rates lagged behind the water table rise, suggesting that recharge was delivered by fractures, which control the cave's morphology. At High Springs, hydrographs at the Santa Fe River and a submerged conduit apparently connected to it show sharp maxima after the storms, unlike the other cave hydrographs. Our interpretation is that the caves, in general, are discontinuous.

  3. 40Ar/ 39Ar dating of Late Permian evaporites, southeastern New Mexico, USA

    Science.gov (United States)

    Renne, Paul R.; Sharp, Warren D.; Montañez, Isabel P.; Becker, Tim A.; Zierenberg, Robert A.

    2001-12-01

    40Ar/ 39Ar dating of the potassium-magnesium sulfate mineral langbeinite from Permian evaporites of the Salado formation near Carlsbad, New Mexico, provides quantitative evidence that some salts in these deposits have not recrystallized for 251 Myr since deposition. Survival of Permian salts supports the possibility that Bacillus bacteria recovered from nearby halite was isolated in a closed system and represents a sample of uncontaminated Permian life. Local recrystallization of langbeinite and other nearby minerals is also indicated by the dating, suggesting both the need and the opportunity to document closed system behavior more rigorously. The shoaling and desiccation event recorded by the Salado formation began at least 1 Myr before the Permian-Triassic boundary. Temporal correlation of the Salado with the Zechstein evaporites of north-central Europe supports previously inferred regression models for the origin of these deposits. Significant paleoenvironmental change at the Permian-Triassic boundary thus occurred on a time scale more protracted than that implied by geologically instantaneous events such as bolide impacts.

  4. Earth analogs for Martian life - Microbes in evaporites, a new model system for life on Mars

    Science.gov (United States)

    Rothschild, Lynn J.

    1990-01-01

    It is suggested that 'oases' in which life forms may persist on Mars could occur, by analogy with terrestrial cases, in (1) rocks, as known in endolithic microorganisms, (2) polar ice caps, as seen in snow and ice algae, and (3) volcanic regions, as witnessed in the chemoautotrophs which live in ocean-floor hydrothermal vents. Microorganisms, moreover, have been known to survive in salt crystals, and it has even been shown that organisms can metabolize while encrusted in evaporites. Evaporites which may occur on Mars would be able to attenuate UV light, while remaining more transparent to the 400-700 nm radiation useful in photosynthesis. Suggestions are made for the selection of Martian exobiological investigation sites.

  5. Process-based karst modelling to relate hydrodynamic and hydrochemical characteristics to system properties

    Directory of Open Access Journals (Sweden)

    A. Hartmann

    2013-08-01

    Full Text Available More than 30% of Europe's land surface is made up of karst exposures. In some countries, water from karst aquifers constitutes almost half of the drinking water supply. Hydrological simulation models can predict the large-scale impact of future environmental change on hydrological variables. However, the information needed to obtain model parameters is not available everywhere and regionalisation methods have to be applied. The responsive behaviour of hydrological systems can be quantified by individual metrics, so-called system signatures. This study explores their value for distinguishing the dominant processes and properties of five different karst systems in Europe and the Middle East. By defining ten system signatures derived from hydrodynamic and hydrochemical observations, a process-based karst model is applied to the five karst systems. In a stepwise model evaluation strategy, optimum parameters and their sensitivity are identified using automatic calibration and global variance-based sensitivity analysis. System signatures and sensitive parameters serve as proxies for dominant processes, and optimised parameters are used to determine system properties. By sensitivity analysis, the set of system signatures was able to distinguish the karst systems from one another by providing separate information about dominant soil, epikarst, and fast and slow groundwater flow processes. Comparing sensitive parameters to the system signatures revealed that annual discharge can serve as a proxy for the recharge area, that the slopes of the high flow parts of the flow duration curves correlate with the fast flow storage constant, and that the dampening of the isotopic signal of the rain as well as the medium flow parts of the flow duration curves have a non-linear relation to the distribution of groundwater storage constants that represent the variability of groundwater flow dynamics. Our approach enabled us to identify dominant processes of the

  6. Regional scale hydrologic modeling of a karst-dominant geomorphology: The case study of the Island of Crete

    Science.gov (United States)

    Malagò, Anna; Efstathiou, Dionissios; Bouraoui, Fayçal; Nikolaidis, Nikolaos P.; Franchini, Marco; Bidoglio, Giovanni; Kritsotakis, Marinos

    2016-09-01

    Crete Island (Greece) is a karst dominated region that faces limited water supply and increased seasonal demand, especially during summer for agricultural and touristic uses. In addition, due to the mountainous terrain, interbasin water transfer is very limited. The resulting water imbalance requires a correct quantification of available water resources in view of developing appropriate management plans to face the problem of water shortage. The aim of this work is the development of a methodology using the SWAT model and a karst-flow model (KSWAT, Karst SWAT model) for the quantification of a spatially and temporally explicit hydrologic water balance of karst-dominated geomorphology in order to assess the sustainability of the actual water use. The application was conducted in the Island of Crete using both hard (long time series of streamflow and spring monitoring stations) and soft data (i.e. literature information of individual processes). The KSWAT model estimated the water balance under normal hydrological condition as follows: 6400 Mm3/y of precipitation, of which 40% (2500 Mm3/y) was lost through evapotranspiration, 5% was surface runoff and 55% percolated into the soil contributing to lateral flow (2%), and recharging the shallow (9%) and deep aquifer (44%). The water yield was estimated as 22% of precipitation, of which about half was the contribution from spring discharges (9% of precipitation). The application of the KSWAT model increased our knowledge about water resources availability and distribution in Crete under different hydrologic conditions. The model was able to capture the hydrology of the karst areas allowing a better management and planning of water resources under scarcity.

  7. Relationship among land surface temperature and LUCC, NDVI in typical karst area.

    Science.gov (United States)

    Deng, Yuanhong; Wang, Shijie; Bai, Xiaoyong; Tian, Yichao; Wu, Luhua; Xiao, Jianyong; Chen, Fei; Qian, Qinghuan

    2018-01-12

    Land surface temperature (LST) can reflect the land surface water-heat exchange process comprehensively, which is considerably significant to the study of environmental change. However, research about LST in karst mountain areas with complex topography is scarce. Therefore, we retrieved the LST in a karst mountain area from Landsat 8 data and explored its relationships with LUCC and NDVI. The results showed that LST of the study area was noticeably affected by altitude and underlying surface type. In summer, abnormal high-temperature zones were observed in the study area, perhaps due to karst rocky desertification. LSTs among different land use types significantly differed with the highest in construction land and the lowest in woodland. The spatial distributions of NDVI and LST exhibited opposite patterns. Under the spatial combination of different land use types, the LST-NDVI feature space showed an obtuse-angled triangle shape and showed a negative linear correlation after removing water body data. In summary, the LST can be retrieved well by the atmospheric correction model from Landsat 8 data. Moreover, the LST of the karst mountain area is controlled by altitude, underlying surface type and aspect. This study provides a reference for land use planning, ecological environment restoration in karst areas.

  8. A new species of karst forest Bent-toed Gecko (genus Cyrtodactylus Gray) not yet threatened by foreign cement companies and a summary of Peninsular Malaysia's endemic karst forest herpetofauna and the need for its conservation.

    Science.gov (United States)

    Grismer, L Lee; Wood, P L Jr; Anuar, Shahrul; Davis, H R; Cobos, A J; Murdoch, M L

    2016-01-04

    A new species of Bent-toed Gecko, Cyrtodactylus gunungsenyumensis sp. nov. of the sworderi complex, is described from Hutan Lipur Gunung Senyum, Pahang, Peninsular Malaysia and is differentiated from all other species in the sworderi complex by having a unique combination of characters including a maximum SVL of 74.7 mm; low, rounded, weakly keeled, body tubercles; 34-40 paravertebral tubercles; weak ventrolateral body fold lacking tubercles; 38-41 ventral scales; an abrupt transition between the posterior and ventral femoral scales; 20-23 subdigital lamellae on the fourth toe; enlarged femoral scales; no femoral or precloacal pores; no precloacal groove; wide caudal bands; and an evenly banded dorsal pattern. Cyrtodactylus gunungsenyumensis sp. nov. is a scansorial, karst forest-adapted specialist endemic to the karst ecosystem surrounding Gunung Senyum and occurs on the vertical walls of the limestone towers as well as the branches, trunks, and leaves of the vegetation in the associated karst forest. Cyrtodactylus gunungsenyumensis sp. nov. is the seventh species of karst forest-adapted Cyrtodactylus and the sixteenth endemic species of karst ecosystem reptile discovered in Peninsular Malaysia in the last seven years from only 12 different karst forests. This is a clear indication that many species remain to be discovered in the approximately 558 isolated karst ecosystems in Peninsular Malaysia not yet surveyed. These data continue to underscore the importance of karst ecosystems as reservoirs of biodiversity and microendemism and that they constitute an important component of Peninsular Malaysia's natural heritage and should be protected from the quarrying interests of foreign industrial companies.

  9. Stable isotope hydrology of a classical karst area, Trieste, Italy

    International Nuclear Information System (INIS)

    Flora, O.; Longinelli, A.

    1989-01-01

    Most of the karst springs that exist along the northeastern coast of the Adriatic Sea in the area of Trieste (Italy) have been studied for about 2 years. These studies were carried out to determine the oxygen isotopic composition of the water and, more recently, the major and minor dissolved ions and the water temperature. The isotopic composition of meteoric waters in different areas was also systematically studied during the same period to obtain basic information on environmental waters. The isotopic curves obtained from the springs generally showed a marked seasonal isotopic inversion. In fact, in most of the springs studied the results obtained from winter samples were the most positive. In contrast, summer samples were usually quite negative, the most negative being those obtained in the late summer months (August to October). The data obtained were considered to be the result of a variable mixing of waters from two different reservoirs. The less negative data probably resulted from 'local' meteoric waters falling on the western section of the karst area, at a mean elevation of about 400 metres above sea level. The most negative data were probably related to meteoric waters falling on the internal part of the karst area, at a mean elevation of about 800 to 900 metres. The isotopic values and the chemistry of the waters appeared to be in reasonable agreement. However, at least in the northern karst springs, it is likely that a third water system, basically fed by the Isonzo River which flows north of the karst highlands, might interfere with the previously mentioned reservoirs, so partially controlling the outflow of some of these springs. (author). 7 refs, 8 figs

  10. Differentiated spring behavior under changing hydrological conditions in an alpine karst aquifer

    Science.gov (United States)

    Filippini, Maria; Squarzoni, Gabriela; De Waele, Jo; Fiorucci, Adriano; Vigna, Bartolomeo; Grillo, Barbara; Riva, Alberto; Rossetti, Stefano; Zini, Luca; Casagrande, Giacomo; Stumpp, Christine; Gargini, Alessandro

    2018-01-01

    Limestone massifs with a high density of dolines form important karst aquifers in most of the Alps, often with groundwater circulating through deep karst conduits and water coming out of closely spaced springs with flow rates of over some cubic meters per second. Although several hydrogeological studies and tracing experiments were carried out in many of these carbonate mountains in the past, the hydrogeology of most of these karst aquifers is still poorly known. Geological, hydrodynamic and hydrochemical investigations have been carried out in one of the most representative of these areas (Cansiglio-Monte Cavallo, NE Italy) since spring 2015, in order to enhance the knowledge on this important type of aquifer system. Additionally, a cave-to-spring multitracer test was carried out in late spring 2016 by using three different fluorescent tracers. This hydrogeological study allowed: 1) gathering new detailed information on the geological and tectonic structure of such alpine karst plateau; 2) defining discharge rates of the three main springs (Gorgazzo, Santissima, and Molinetto) by constructing rating curves; 3) understanding the discharging behavior of the system with respect to different recharge conditions; 4) better defining the recharge areas of the three springs. The three nearby springs (the spring front stretches over 5 km), that drain the investigated karst aquifer system, show different behaviors with respect to changing discharge conditions, demonstrating this aquifer to be divided in partially independent drainage systems under low-flow conditions, when their chemistry is clearly differentiated. Under high-flow conditions, waters discharging at all springs show more similar geochemical characteristics. The combination of geochemistry, hydrodynamic monitoring and dye tracing tests has shown that the three springs have different recharge areas. The study points out that even closely spaced karst springs, that apparently drain the same karst mountain, can

  11. Effectiveness of airborne multispectral thermal data for karst groundwater resources recognition in coastal areas

    Science.gov (United States)

    Pignatti, Stefano; Fusilli, Lorenzo; Palombo, Angelo; Santini, Federico; Pascucci, Simone

    2013-04-01

    and the retrieving of accurate sea surface temperatures (SST) allowed us to detect and identify thermal anomalies related to coastal and submarine karst springs. In particular, the preprocessing for both MIVIS and TASI-600 sensors was carried out as follows: (a) radiometric calibration of the raw data by using the RADCORR software provided by ITRES (Canada) and the application of a new correction tool for blinking pixel correction, developed by CNR (Italy); (b) atmospheric compensation of the TIR data by applying the ISAC (In-Scene Atmospheric Compensation) algorithm [7]; (c) calibration to temperature by separating temperature and emissivity according to the methods described by [8]. This study points out that considerable water resources are dispersed into the sea, through karst springs and such water resources could be effectively protected in artificial way against the salting sea water influence and exploited for human local uses. The obtained preliminary results are encouraging, even though suitable integration approaches also with the classical geophysical investigation techniques have to be improved for rapid and cost-effective karst groundwater resources detection and monitoring. Table 1. Characteristics of sensors used for this study. Spectral Region Bands Spectral Resolution Spectral Range IFOV Spatial Resolution MIVISVNIR-SWIR LWIR 92 10 90-500 nm 340-540 nm 0.4÷12.7 μm 8.2÷12.7 μm 2.0 mrad3 m TASI LWIR 32 100 nm 8.0÷11.5 μm 1.2 mrad1 m References Jemcov, I. 2007. Water supply potential and optimal exploitation capacity of karst aquifer systems. Environm. Geol., vol. 51, 767-773. Bakalowicz, M. 2005. Karst groundwater: a challenge for new resources. Hydrogeology Journal, vol. 13, pp. 148-160. Milanovic, S. 2007. Hydrogeological characteristics of some deep siphonal springs in Serbia and Montenegro karst. Environmental Geology, vol 51, p.p. 755-759. Avanzi, G., Palombo, A., Pignatti, S. 2006. MIVIS image geocoding experience on merging position

  12. Speleogenesis, geometry, and topology of caves: A quantitative study of 3D karst conduits

    Science.gov (United States)

    Jouves, Johan; Viseur, Sophie; Arfib, Bruno; Baudement, Cécile; Camus, Hubert; Collon, Pauline; Guglielmi, Yves

    2017-12-01

    Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of

  13. Bullita cave system, Judbarra / Gregory Karst, tropical Australia; Sistemas de cuevas de Bullita, Judbarra / Gregory Karst, Australia tropical

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, K. G.; Martini, J. E. J.

    2016-07-01

    In the monsoon tropics of northern Australia, Bullita Cave is the largest (123 km) of a group of extensive, horizontal, joint-controlled, dense network maze caves which are epikarst systems lying at shallow depth beneath a well-developed karrenfield. The Judbarra / Gregory Karst and its caves are restricted to the outcrop belt of the thin, sub-horizontal, Proterozoic Supplejack Dolostone. Karst is further restricted to those parts of the Supplejack that have escaped a secondary dolomitisation event. The karrenfield and underlying cave system are intimately related and have developed in step as the Supplejack surface was exposed by slope retreat. Both show a lateral zonation of development grading from youth to old age. Small cave passages originate under the recently exposed surface, and the older passages at the trailing edge become un roofed or destroyed as the, by then deeply-incised, karrenfield breaks up into isolated ruiniform blocks and pinnacles. Vertical development of the cave has been generally restricted to the epikarst zone by a 3m bed of impermeable and incompetent shale beneath the Supplejack which first perched the water-table, forming incipient phreatic passages above it, and later was eroded by vadose flow to form an extensive horizontal system of passages 10-20m below the karren surface. Some lower cave levels in underlying dolostone occur adjacent to recently incised surface gorges. Speleogenesis is also influenced by the rapid, diffuse, vertical inflow of storm water through the karrenfield, and by ponding of the still-aggressive water within the cave during the wet season dammed up by levees of sediment that accumulate beneath the degraded trailing edge of the karrenfield. The soil, and much biological activity, is not at the bare karren surface, but down on the cave floors, which aids epikarstic solution at depth rather than on the surface. (Author)

  14. Using streamflow and hydrochemical tracers to conceptualise hydrological function of underground channel system in a karst catchment of southwest China

    Science.gov (United States)

    Zhang, Zhicai; Chen, Xi; Wang, Jinli

    2016-04-01

    Karst hydrodynamic behaviour is complex because of special karst geology and geomorphology. The permeable multi-media consisting of soil, epikarst fractures and conduits has a key influence on karst hydrological processes. Spatial heterogeneity is high due to special landforms of vertical shafts, caves and sinkholes, which leads to a high dynamic variability of hydrological processes in space and time, and frequent exchange of surface water and groundwater. Underground water in different reach were sampled over the 1996-2001 in a karst catchment of Houzhai, with 81km2, located in Guizhou province of southwest China. Samples were analysed for water temperature, pH, conductivity and four solute concentrations. The monitoring sought to assess the combined utility of flow discharge and natural geochemical tracers in upscaling flow structure understanding in karst area. Based on previous researches and field investigation, the catchment characteristics were explored with the use of a GIS. Both flow discharge and solute concentrations exhibited clear seasonal patterns at every groundwater sampling sites. The variations of flow and chemistry are more dramatic in upstream site with less soil cover and more sinkholes development, which affect the hydrological pathways significantly. There was clear evidence that the differences in geology and soil were the main controls on hydrology and flow chemistry, which was spatially variable in different sites of underground channel. Conceptual flow structures in main hydrological response units for different area in the catchment were developed according to the variation of discharge and flow chemistry.

  15. Kajian Kerusakan Lingkungan Karst sebagai Dasar Pelestarian Sumberdaya Air (Kasus di DAS Bribin Hulu Kabupaten Gunung Kidul Daerah Istimewa Yogyakarta

    Directory of Open Access Journals (Sweden)

    Raras Endarto

    2016-09-01

    ABSTRACT Groundwater resources in Gunung Kidul Regency synonymous with underground system Bribin  (Bribin watershed. Reservoir Bribin 1, Bribin 2, and Seropan located in the Dadapayu village Semanu Sub-District utilize to comply needs of population  in Gunung Kidul Regency. Existance of Bribin Watershed is very important for continuance and welfare of population which must be managed sustainability. Environmental management in order to achieve sustainability of water resources was emphasized on water recharge, namely Bribin Watershed of upstream section. Identification extent of damage in Bribin Watershed into one of urgency things because the area as underground supplier into reservoir river of Bribin, Baron, and Seropan was utilized for the needs of population. Extent damage of karst is assessed based on morphology of karst basin. This research was conducted using field observations and literature studies related to condition os study area. Considered of  karst damage parameters, includes morphology change caused by mining, existance outlet basin, land cover, condition of springs, caves, and existance of building over the karst surface must be conducted assessment in extent of damage. Administratively, extent of damage karst is very high located in Kenteng, Karangasem, and Bedoyo Village, area of 922.27 hectares. The high levels of extent of damage karst is Ponjong, Sawahan, Sumbergiri Village, area of 9424.24 hectares. The high levels of extent of damage karst among others, existance of great mining, springs, and building over the karst surface. Efforts conservation and management strategies commits based on characteristic karst and regional. Karst management policy strategies based on characteristic karst was pressed in surface appearace(eksokarst. Karst management policy strategies based on regional are management karst area plan overall. Water resources management is related to existence of karst component (eksokarst, include management of springs

  16. Macroinvertebrate diversity in the karst Jadro River (Croatia

    Directory of Open Access Journals (Sweden)

    Rađa Biljana

    2008-01-01

    Full Text Available This paper presents the results of 10 years of investigation of the aquatic macroinvertebrate fauna along the karst Jadro River. The Jadro is a typical karst river. Benthic macroinvertebrates were collected along the river at 15 sites by standard methods of sampling, in addition to which several physicochemical parameters were also determined. Based on qualitative and quantitative composition of the macroinvertebrate fauna, correspondence analysis divided the river course into three sections: upstream, midcourse, and downstream. Forty-three taxa were recorded. Results of saprobiological analysis based on macrozoobenthos indicate that water of the Jadro River belongs to quality classes I and II.

  17. Fate of Organic Matters in a Soil Erosion Context : Qualitative and Quantitative Monitoring in a Karst Hydrosystem

    Science.gov (United States)

    Quiers, M.; Gateuille, D.; Perrette, Y.; Naffrechoux, E.; David, B.; Malet, E.

    2017-12-01

    Soils are a key compartments of hydrosystems, especially in karst aquifers which are characterized by fast hydrologic responses to rainfalls. In steady state, soils are efficient filters preventing karst water from pollutions. But agricultural or forestry land uses can alter or even reverse the role of soils. Thus , soils can act as pollution sources rather than pollution filters. In order to manage water quality together with man activities in karst environment, the development of new tools and procedures designed to monitor the fate of soil organic matter are needed. This study reports two complementary methods applied in a moutain karst system impacted by anthropic activities and environmental stresses. A continuous monitoring of water fluorescence coupled with punctual sampling was analyzed by chemiometric methods and allowed to discriminate the type of organic matter transferred through the karst system along the year (winter / summer) and hydrological stages. As a main result, the modelisation of organic carbone fluxes is dominated by a colloidal or particulate part during highwaters, and a main part dissolved in solution during low water, demonstrating the change of organic carbone source. To confirm this result, a second method was used based on the observation of Polycyclic Aromatic Hydrocarbons (PAH) profiles. Two previous studies (Perrette et al 2013, Schwarz et al 2011) led to opposite conclusions about the fate of PAH from soil to groundwaters. This opposition leads to a potential use of PAH profiles (low molecular weight less hydrophobic ones versus high molecular weight more hydrophobic ones) as an indicator of soil erosion. We validate that use by the anaylsis of these PAH profiles for low and high waters (floods). These results demonstrate if needed the high vulnerability of karst system to soil erosion, and propose a new proxy to record soils erosion in groundwaters and in natural archives as stalagmites or sediments.

  18. Integration of potential and quasipotential geophysical fields and GPR data for delineation of buried karst terranes in complex environments

    Science.gov (United States)

    Eppelbaum, L. V.; Alperovich, L. S.; Zheludev, V.; Ezersky, M.; Al-Zoubi, A.; Levi, E.

    2012-04-01

    Karst is found on particularly soluble rocks, especially limestone, marble, and dolomite (carbonate rocks), but is also developed on gypsum and rock salt. Subsurface carbonate rocks involved in karst groundwater circulation considerably extend the active karst realm, to perhaps 14% of the world's land area (Price, 2009). The phenomenon of the solution weathering of limestone is the most widely known in the world. Active sinkholes growth appears under different industrial constructions, roads, railways, bridges, airports, buildings, etc. Regions with arid and semi-arid climate occupy about 30% of the Earth's land. Subsurface in arid regions is characterized by high variability of physical properties both on lateral and vertical that complicates geophysical survey analysis. Therefore for localization and monitoring of karst terranes effective and reliable geophysical methodologies should be applied. Such advanced methods were developed in microgravity (Eppelbaum et al., 2008; Eppelbaum, 2011b), magnetic (Khesin et al., 1996; Eppelbaum et al., 2000, 2004; Eppelbaum, 2011a), induced polarization (Khesin et al., 1997; Eppelbaum and Khesin, 2002), VLF (Eppelbaum and Khesin, 1992; Eppelbaum and Mishne, 2012), near-surface temperature (Eppelbaum, 2009), self-potential (Khesin et al., 1996; Eppelbaum and Khesin, 2002), and resistivity (Eppelbaum, 1999, 2007a) surveys. Application of some of these methodologies in the western and eastern shores of the Dead Sea area (e.g., Eppelbaum et al., 2008; Ezersky et al., 2010; Al-Zoubi et al., 2011) and in other regions of the world (Eppelbaum, 2007a) has shown their effectiveness. The common procedures for ring structure identification against the noise background and probabilistic-deterministic methods for recognizing the desired targets in complex media are presented in Khesin and Eppelbaum (1997), Eppelbaum et al. (2003), and Eppelbaum (2007b). For integrated analysis of different geophysical fields (including GPR images) intended

  19. Factors Affecting Public-Supply Well Vulnerability in Two Karst Aquifers

    OpenAIRE

    Musgrove, MaryLynn; Katz, Brian G; Fahlquist, Lynne S; Crandall, Christy A; Lindgren, Richard J

    2014-01-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearb...

  20. Nitrogen loss from karst area in China in recent 50 years: An in-situ simulated rainfall experiment's assessment.

    Science.gov (United States)

    Song, Xianwei; Gao, Yang; Green, Sophie M; Dungait, Jennifer A J; Peng, Tao; Quine, Timothy A; Xiong, Bailian; Wen, Xuefa; He, Nianpeng

    2017-12-01

    Karst topography covers more than 1/3 of the People's Republic of China in area. The porous, fissured, and soluble nature of the underlying karst bedrock (primarily dolomite and limestone) leads to the formation of underground drainage systems. Karst conduit networks dominate this system, and rainfall takes a crucial role on water cycle at China karst area. Nitrogen loss from the karst system is of particular concern, with regard to nutrient use efficiency as well as water quality, as much of the karst system, including steeply sloping terrain, is used for intensive agriculture. We use simulated rainfall experiments to determine the relationship between rainfall and nitrogen loss at typical karst slope land and then estimate nitrogen loss from the karst soil. The results show that both surface runoff and subsurface runoff have a significant linear correlation with rainfall at all studied sites. Subsurface runoff is larger than surface runoff at two karst sites, while the opposite is true at the non-karst site. Exponential function satisfactorily described the correlation between rainfall and nitrogen concentrations in runoff. Nitrates accounted for 60%-95% of the dissolved nitrogen loss (DN, an index of N-loss in this research). The estimated annual N-loss load varies between 1.05 and 1.67 Tg N/year in the whole karst regions of China from 1961 to 2014. Approximately, 90% of the N-loss load occurred during the wet season, and 90% of that passed through the subsurface. Understanding the processes and estimating N-loss is highly valuable in determining long-term soil security and sustainability in karst regions.

  1. Evaluating disturbance on mediterranean karst areas: the example of Sardinia (Italy)

    Science.gov (United States)

    de Waele, Jo

    2009-07-01

    Evaluating the human disturbance on karst areas is a difficult task because of the complexity of these peculiar and unique environments. The human impact on karstic geo-ecosystems is increasingly important and there is an increasing need for multidisciplinary tools to assess the environmental changes in karst areas. Many disciplines, such as biology, geomorphology, hydrology and social-economical sciences are to be considered to sufficiently evaluate the impact on these intrinsically vulnerable areas. This article gives an overview of the evolution of environmental impact on karst areas of the island Sardinia (Italy). For this particular case, the most important impacts in the past 50 years are derived from the following activities, in decreasing importance: (1) mining and quarrying; (2) deforestation, agriculture and grazing; (3) building (widespread urbanisation, isolated homes, etc.) and related infrastructures (roads, sewer systems, aqueducts, waste dumps, etc.); (4) tourism; (5) military activities. To evaluate the present environmental state of these areas the Disturbance Index for Karst environments [Van Beynen and Townsend (Environ Manage 36:101-116)] is applied in a slightly modified version. Instead of considering the indicators of environmental disturbances used in the original method, this slightly modified index evaluates the disturbances causing the deterioration of the environmental attributes. In the Sardinian case study, 27 disturbances have been evaluated, giving rise to the definition of a Disturbance Index ranging between 0 (Pristine) and 1 (highly disturbed). This Disturbance Index simplifies the original KDI method, appears to adequately measure disturbance on Mediterranean karst areas and could be applied with success to other similar regions.

  2. Differences between caves with and without bats in a Brazilian karst habitat

    Directory of Open Access Journals (Sweden)

    Camila G. Torquetti

    2017-10-01

    Full Text Available ABSTRACT. Since bats shelter in roosts during their period of diurnal inactivity, the quality and availability of roosts are important aspects of their ecology. Karst areas have great potential for the availability of day roosts, since they form caves, which serve as bat shelters. Here we characterize the caves used by bats in a preserved karst area of Southeastern Brazil. Using logistic regression analysis we identified the cave characteristics that influence bat occupation. Sixty-six caves were characterized based on measurements of internal height and width, height and width of the entrance(s of the cave, number of entrances, maximum horizontal development of cave, and internal temperature and humidity. In nineteen months we found 14 species in 32 caves. Most species were eventually recorded in multiple caves, with the exception of D. rotundus, G. soricina and A. planirostris, which were always found in the same caves. Desmodus rotundus showed maternity roost fidelity. We found no differences in microclimate between the caves that are occupied and those that are not. In other words, the microclimate of the caves studied herein can be characterized as stable over the years. The only predictor affecting the presence of bats in the study area was the cave’s maximum horizontal development: the caves that are occupied have greater horizontal development. Based on our results, we conclude that bats occupy many of the caves and that some species are more frequent in certain caves than in others, including some roosts that are used as maternity roosts. These findings indicate that these caves are important resources for the bats in the karst environment studied, and should be preserved.

  3. Pesticides and biocides in a karst catchment: Identification of contaminant sources and related flow components

    Science.gov (United States)

    Wagner, Thomas; Bollmann, Ulla E.; Bester, Kai; Birk, Steffen

    2013-04-01

    Karst aquifers are widely used as drinking water resources. However, their high vulnerability to chemical and bacterial contamination due to the heterogeneity in aquifer properties (highly conductive solution conduits embedded in the less conductive fissured rock) is difficult to assess and thus poses major challenges to the management of karst water resources. Contamination of karst springs by organic micro-pollutants has been observed in recent studies. Within this study the water from different springs draining one karst aquifer as well as the main sinking stream replenishing it were analysed before, during and after a storm water event in order to examine the occurrence of different pesticides and biocides. Contaminants from both urban as well as agricultural origin could be detected in the water with concentrations in the low ng/L range (tebuconazole, carbendazim, diuron, isoproturon, terbutryn, atrazine, dichlorobenzamide (BAM), which is a metabolite of dichlobenil). While some compounds could be followed from the sinking stream to the springs (e.g. dichlorobenzamide) some seem to have a source in the autogenic recharge from the karst plateau (Tebuconazole: wood preservative in buildings). These compounds appear to be related to fast flow components with residence times in the order of days, which are known from a number of tracer tests with fluorescent dyes. However, the occurrence of the pesticide atrazine (banned since 1995 in Austria) in the springs, while on the other hand no current input into the karst occurs, shows that some compounds have long residence times in the karst aquifer. These differences in residence times can hardly be attributed to differences in physico-chemical properties of the compounds and must thus be due to the presence of slow and fast flow components. This is in agreement with the duality of karst aquifers due to highly conductive networks of solution conduits embedded in less conductive fissured carbonate rocks.

  4. Summary of United States Geological Survey investigations of fluid-rock-waste reactions in evaporite environments under repository conditions

    International Nuclear Information System (INIS)

    Stewart, D.B.; Jones, B.F.; Roedder, E.; Potter, R.W. II

    1980-01-01

    The interstitial and inclusion fluids contained in rock salt and anhydrite, though present in amounts less than 1 weight per cent, are chemically aggressive and may react with canisters or wastes. The three basic types of fluids are: (1) bitterns residual from saline mineral precipitation including later recrystallization reactions; (2) brines containing residual solutes from the formation of evaporite that have been extensively modified by reactions with contiguous carbonate of clastic rocks; and (3) re-solution brines resulting from secondary dehydration of evaporite minerals or solution of saline minerals by undersaturated infiltrating waters. Fluid composition can indicate that meteoric flow systems have contacted evaporites or that fluids from evaporites have migrated into other formations. The movement of fluids trapped in fluid inclusions in salt from southeast New Mexico is most sensitive to ambient temperature and to inclusion size, although several other factors such as thermal gradient and vapour/liquid ratio are also important. There is no evidence of a threshold temperature for movement of inclusions. Empirical data are given for determining the amount of brine reaching the heat source if the temperature, approximate amount of total dissolved solids, and Ca:Mg ratio in the brine are known. SrCl 2 and CsCl can reach high concentrations in saturated NaCl solutions and greatly depress the liquidus. The possibility that such fluids, if generated, could migrate from a high-level waste repository must be minimized because the fluid would contain its own radiogenic energy source in the first decades after repository closure, thus changing the thermal evolution of the repository from designed values. (author)

  5. Low temperature geothermal systems in carbonate-evaporitic rocks: Mineral equilibria assumptions and geothermometrical calculations. Insights from the Arnedillo thermal waters (Spain).

    Science.gov (United States)

    Blasco, Mónica; Gimeno, María J; Auqué, Luis F

    2018-02-15

    Geothermometrical calculations in low-medium temperature geothermal systems hosted in carbonate-evaporitic rocks are complicated because 1) some of the classical chemical geothermometers are, usually, inadequate (since they were developed for higher temperature systems with different mineral-water equilibria at depth) and 2) the chemical geothermometers calibrated for these systems (based on the Ca and Mg or SO 4 and F contents) are not free of problems either. The case study of the Arnedillo thermal system, a carbonate-evaporitic system of low temperature, will be used to deal with these problems through the combination of several geothermometrical techniques (chemical and isotopic geothermometers and geochemical modelling). The reservoir temperature of the Arnedillo geothermal system has been established to be in the range of 87±13°C being the waters in equilibrium with respect to calcite, dolomite, anhydrite, quartz, albite, K-feldspar and other aluminosilicates. Anhydrite and quartz equilibria are highly reliable to stablish the reservoir temperature. Additionally, the anhydrite equilibrium explains the coherent results obtained with the δ 18 O anhydrite - water geothermometer. The equilibrium with respect to feldspars and other aluminosilicates is unusual in carbonate-evaporitic systems and it is probably related to the presence of detrital material in the aquifer. The identification of the expected equilibria with calcite and dolomite presents an interesting problem associated to dolomite. Variable order degrees of dolomite can be found in natural systems and this fact affects the associated equilibrium temperature in the geothermometrical modelling and also the results from the Ca-Mg geothermometer. To avoid this uncertainty, the order degree of the dolomite present in the Arnedillo reservoir has been determined and the results indicate 18.4% of ordered dolomite and 81.6% of disordered dolomite. Overall, the results suggest that this multi

  6. Palaeoredox indicators from the organic-rich Messinian early post-evaporitic deposits of the Apennines (Central Italy)

    Science.gov (United States)

    Sampalmieri, G.; Iadanza, A.; Cipollari, P.; Cosentino, D.; Lo Mastro, S.

    2009-04-01

    Bottom redox conditions in marine and lacustrine ancient basins are often inferred by the occurrence of peculiar sedimentological structures and microfaunal assemblages. The co-occurrence, in such environments, of authigenic uranium, framboidal pyrite, barite and Fe-Mn nodules and encrustations, provides a good constraint for palaeo reconstructions. Authigenic uranium is a common constituent of hydrocarbon source rocks: it forms at the sediment-water interface under oxygen-deficient conditions and accumulates together with organic matter (OM). Its precipitation is triggered by the reduction of the soluble U6+ion in seawater to insoluble U4+. With respect to black shales, uranium content has even been used to estimate the TOC. Also authigenic pyrite forms under anoxic conditions and replaces organic matter: 1) the increase in pyrite content and in organic matter are directly correlated; 2) the size distribution of framboidal pyrite (consistent with sulphate-reducing bacterial activity) is considered a measure of redox conditions within the sediment. Barite is an authigenic mineral related to Corg content, since its organic precipitation is triggered by sulphate-reduction processes occurring in decaying OM-bearing microenvironments. Finally, also Fe-Mn oxyhydroxide are typical indicators of redox conditions. About 6 My ago the Mediterranean Sea underwent a giant event of concentration referred to as Messinian Salinity Crisis, which can be roughly subdivided into an evaporitic and a post evaporitic phase. The post evaporitic phase (p-ev; 5.61-5.33 Ma) developed in a context of humid conditions and can be further distinguished into two steps: p-ev1 (early post evaporitic phase) and p-ev2 (late post evaporitic phase). Previous works focused on pev2, which is interpreted to represent the establishment of brackish water conditions (Lago-Mare biofacies). In other respects, the palaeoenvironment of p-ev1 deposits, mostly represented by resedimented evaporitic deposits or

  7. The origin and evolution of the term "karst"%术语"Karst"的起源和演化

    Institute of Scientific and Technical Information of China (English)

    Andrej Kranjc

    2011-01-01

    statements.Recent linguistic studies provide some new results regarding the word karst.The paper repeats some well known facts about the origin of the term karst but at the same time it gives some new results and interpretations.The name of the plateau in the background of the Trieste Bay (the Adriatic Sea) which the Slovenes call Kras,Italians Carso and Germans Karst is of pre-roman origin and Latinised into Carsus.The original name had the base * Karus-( Ptolemy wrote Kαpouσαδíωóρε) from the root * kar- meaning rock,stone.From the Latinised form Carsus developed Slovene,Italian and German names according to the rules of their languages.From the Central Europe the easiest and practically the only way leading to the Mediterranean was the road from Vienna to the port of Trieste.Travellers across the Karst described this unusual country and its natural phenomena,mostly with negative connotation and subsequently other limestone landscapes were compared to Karst.In 1830 F.J.H.Hohenwart wrote that "karst is not on the Karst only,but it stretches from the plain of Friuli to the Greek islands".Most of the descriptions of the Karst from that period were published in German language and this is the reason why the German form of the name became the international karstological term,the karst.

  8. Runoff response to climate change and human activities in a typical karst watershed, SW China.

    Science.gov (United States)

    Xu, Yan; Wang, Shijie; Bai, Xiaoyong; Shu, Dongcai; Tian, Yichao

    2018-01-01

    This study aims to reveal the runoff variation characteristics of long time series in a karst region, analyse comprehensively its different driving factors, and estimate quantitatively the contribution rates of climate change and human activities to net runoff variation. Liudong river basin, a typical karst watershed in southwest China, is the study site. Statistical methods, such as linear fitting, the Morlet wavelet analysis, normalized curve and double mass curve, are applied to analyse the runoff of the watershed. Results show that the runoff in the karst watershed during the research period exhibits a three-stage change and the abrupt change points are the years 1981 and 2007: (1) 1968-1980, the runoff initially exhibited a trend of sustained decreasing and then an abrupt fluctuation. The runoff was obviously destroyed through precipitation-producing processes. Improper land utilisation and serious forest and grass destruction intensified the fluctuation variation amplitude of the runoff. (2) 1981-2006, the changing processes of runoff and precipitation exhibited good synchronism. Precipitation significantly affected runoff variation and human activities had a slight interference degree. (3) 2007-2013, the fluctuation range of runoff was considerably smaller than that of precipitation. The significant growth of forest and grassland areas and the increase in water consumption mitigated runoff fluctuation and greatly diminished runoff variation amplitude. According to calculation, the relative contribution rates of precipitation and human activities to net runoff variation with 1981-2007 as the reference period were -81% and 181% in average, respectively, during 1968-1980, and -117% and 217% in average, respectively, during 2007-2013. In general, the analysis of runoff variation trend and of the contribution rate of its main influencing factors in the typical karst watershed for nearly half a century may be significant to solve the drought problem in the karst

  9. Hochauflösendes Monitoring von Karst-Grundwasserressourcen beiderseits des Jordangrabens - Konzepte und Anwendungsbeispiele

    Science.gov (United States)

    Schmidt, Sebastian; Grimmeisen, Felix; Ries, Fabian; Goldscheider, Nico; Sauter, Martin

    2018-03-01

    In the semi-arid eastern Mediterranean water supply is highly dependent on karst aquifers. The region is characterized by multi-year dry and wet cycles combined with high hydrological dynamics, especially during intense precipitation events. The investigated karst regions in the West Bank and Jordan are experiencing strong urbanization within the groundwater catchments and hence a rising impact on water quality. Therefore, high resolution monitoring data are required for the assessment of available water resources and the hydrogeological characterization of the karst systems. These measurements are focused on the (natural) meteorological input signals and the system output signals at the karst springs. Also soil moisture and ephemeral runoff dynamics are investigated. The monitoring data enable (1) hydrogeological characterization of the aquifers, (2) estimation of groundwater recharge via soil water balance and reservoir models, and (3) assessment of contamination dynamics in groundwater (e. g. nitrate and E. coli concentrations), allowing an optimized raw water management. Several examples illustrate the importance of high-resolution hydrological monitoring data.

  10. Organic carbon storage in four ecosystem types in the karst region of southwestern China.

    Directory of Open Access Journals (Sweden)

    Yuguo Liu

    Full Text Available Karst ecosystems are important landscape types that cover about 12% of the world's land area. The role of karst ecosystems in the global carbon cycle remains unclear, due to the lack of an appropriate method for determining the thickness of the solum, a representative sampling of the soil and data of organic carbon stocks at the ecosystem level. The karst region in southwestern China is the largest in the world. In this study, we estimated biomass, soil quantity and ecosystem organic carbon stocks in four vegetation types typical of karst ecosystems in this region, shrub grasslands (SG, thorn shrubbery (TS, forest - shrub transition (FS and secondary forest (F. The results showed that the biomass of SG, TS, FS, and F is 0.52, 0.85, 5.9 and 19.2 kg m(-2, respectively and the corresponding organic cabon storage is 0.26, 0.40, 2.83 and 9.09 kg m(-2, respectively. Nevertheless, soil quantity and corresponding organic carbon storage are very small in karst habitats. The quantity of fine earth overlaying the physical weathering zone of the carbonate rock of SG, TS, FS and F is 38.10, 99.24, 29.57 and 61.89 kg m(-2, respectively, while the corresponding organic carbon storage is only 3.34, 4.10, 2.37, 5.25 kg m(-2, respectively. As a whole, ecosystem organic carbon storage of SG, TS, FS, and F is 3.81, 4.72, 5.68 and 15.1 kg m(-2, respectively. These are very low levels compared to other ecosystems in non-karst areas. With the restoration of degraded vegetation, karst ecosystems in southwestern China may play active roles in mitigating the increasing CO2 concentration in the atmosphere.

  11. Combining hydraulic model, hydrogeomorphological observations and chemical analyses of surface waters to improve knowledge on karst flash floods genesis

    Directory of Open Access Journals (Sweden)

    F. Raynaud

    2015-06-01

    Full Text Available During a flood event over a karst watershed, the connections between surface and ground waters appear to be complex ones. The karst may attenuate surface floods by absorbing water or contribute to the surface flood by direct contribution of karst waters in the rivers (perennial and overflowing springs and by diffuse resurgence along the hillslopes. If it is possible to monitor each known outlet of a karst system, the diffuse contribution is yet difficult to assess. Furthermore, all these connections vary over time according to several factors such as the water content of the soil and underground, the rainfall characteristics, the runoff pathways. Therefore, the contribution of each compartment is generally difficult to assess, and flood dynamics are not fully understood. To face these misunderstandings and difficulties, we analysed surface waters during six recent flood events in the Lirou watershed (a karst tributary of the Lez, in South of France. Because of the specific chemical signature of karst waters, chemical analyses can supply information about water pathways and flood dynamics. Then, we used the dilution law to combine chemical results, flow data and field observations to assess the dynamics of the karst component of the flood. To end, we discussed the surface or karst origin of the waters responsible for the apparent runoff coefficient rise during flash karst flood.

  12. Analysis of human induced changes in a karst landscape - the filling of dolines in the Kras plateau, Slovenia.

    Science.gov (United States)

    Kovačič, Gregor; Ravbar, Nataša

    2013-03-01

    A comprehensive analysis of the increased pressure on karst landscapes due to expansive economic and urban development is presented with the aim of evaluating changes in land use and their deleterious effects on karst relief forms. The study focuses on two areas surrounding the relatively quickly growing settlements of Hrpelje-Kozina and Divača on the Kras plateau (Slovenia) that have been subjected to intensive urban and business development and traffic since the motorway was brought to their vicinity fifteen years ago. National legislation loopholes and technological improvement were the cause of the commonly unsupervised human encroachment which caused the widespread degradation of the landscape. By comparing different topographical and ortophotographical materials from the past four decades and by detailed field inspection of land use and environmental changes, as well as the morphometrical characterization of dolines, the following results have been found: due to the population growth in the past four decades (39% and 50%, respectively), an increase of settlement area by 18 and 11 percentage points took place. Consequently, between 25 and 27% of dolines have disappeared or have been extensively modified (filled up and leveled). According to the local spatial plans, an additional 18% to 28% dolines are endangered. Broad human induced changes in the karst landscape have resulted in a noticeable increase in landscape deterioration, which is consistent with similar phenomena observed in other regions. Due to the extreme susceptibility of the karst to human activities that may lead to the degradation of its exceptional esthetic and environmental value, the alteration of karst processes such as corrosion, endangering of unique habitats and the quality of non-renewable natural resources, it is necessary to promptly define measures for its protection at the national level. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Investigation of bacterioplankton communities in aquatic karst pools in Bärenschacht cave of Bernese Oberland

    OpenAIRE

    Shabarova, T; Pernthaler, J

    2009-01-01

    Karst subterraneous aquifers are highly diverse in structure and very important in the formation of ground water, which is the main source of freshwater supply for a significant proportion of the world’s population. Microorganisms can play an important role in karstification, carbon cycle and element mobility, but so far little is known about the bacteria of aquatic karst ecosystems. In this study, karst pools with differing hydrology in the Bärenschacht cave of the Bernese Oberla...

  14. Selected Micropollutants as Indicators in a Karst Catchment

    Science.gov (United States)

    Zirlewagen, Johannes; Schiperski, Ferry; Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Scheytt, Traugott

    2015-04-01

    High flow dynamics and variations in water quality are typical for karst springs and reflect the complex interaction of different flow and storage components within a karst system. Event-based monitoring of mobile micropollutants in spring water combined with information on their input is used (1) to quantify the impact of certain contamination scenarios on spring water quality and (2) to gain additional information on the intrinsic characteristics of a karst system. We employ the artificial sweeteners acesulfame and cyclamate as source specific indicators for sewage along with the herbicides atrazine and isoproturon for agriculture. The study site is the 45 km² rural catchment of the perennial karst spring Gallusquelle in SW-Germany (mean discharge: 0.5 m³/s). Overflow events of a stormwater detention basin (SDB, combined sewer system) are known to impact water quality. Most of the sewer system is situated in the SW of the catchment. Most agricultural land is found in the NE. Neither atrazine nor significant amounts of isoproturon were detected in wastewater. Concentrations and mass fluxes of acesulfame and cyclamate in wastewater were determined. The combined evaluation of the persistent compound acesulfame with the rather degradable cyclamate allows for the distinction of long and short transit times and thus slow and fast flow components. The same applies for atrazine (persistent) and isoproturon (degradable). In Germany, acesulfame was licensed in 1990, atrazine was banned shortly after, in 1991. During low flow conditions only atrazine (max. 4 ng/L) and acesulfame (max. 20 ng/L) were detected in spring water. After a recharge event without SDB overflow concentrations as well as mass fluxes of both compounds decreased, reflecting an increasing portion of event water in spring discharge. A breakthrough of isoproturon (max. 9 ng/L) indicated the arrival of water from croplands. After a recharge event accompanied by a SDB overflow cyclamate was detected at max

  15. Analysis of the maximum discharge of karst springs

    Science.gov (United States)

    Bonacci, Ognjen

    2001-07-01

    Analyses are presented of the conditions that limit the discharge of some karst springs. The large number of springs studied show that, under conditions of extremely intense precipitation, a maximum value exists for the discharge of the main springs in a catchment, independent of catchment size and the amount of precipitation. Outflow modelling of karst-spring discharge is not easily generalized and schematized due to numerous specific characteristics of karst-flow systems. A detailed examination of the published data on four karst springs identified the possible reasons for the limitation on the maximum flow rate: (1) limited size of the karst conduit; (2) pressure flow; (3) intercatchment overflow; (4) overflow from the main spring-flow system to intermittent springs within the same catchment; (5) water storage in the zone above the karst aquifer or epikarstic zone of the catchment; and (6) factors such as climate, soil and vegetation cover, and altitude and geology of the catchment area. The phenomenon of limited maximum-discharge capacity of karst springs is not included in rainfall-runoff process modelling, which is probably one of the main reasons for the present poor quality of karst hydrological modelling. Résumé. Les conditions qui limitent le débit de certaines sources karstiques sont présentées. Un grand nombre de sources étudiées montrent que, sous certaines conditions de précipitations extrêmement intenses, il existe une valeur maximale pour le débit des sources principales d'un bassin, indépendante des dimensions de ce bassin et de la hauteur de précipitation. La modélisation des débits d'exhaure d'une source karstique n'est pas facilement généralisable, ni schématisable, à cause des nombreuses caractéristiques spécifiques des écoulements souterrains karstiques. Un examen détaillé des données publiées concernant quatre sources karstiques permet d'identifier les raisons possibles de la limitation de l'écoulement maximal: (1

  16. About Fundamental Problems of Hydrosphere and Silicate Karst

    Directory of Open Access Journals (Sweden)

    A. Ya. Gayev

    2017-09-01

    Full Text Available Rationale of hydrosphere model with two regions of supply and discharge reveals regularities of ground water formation reflecting the special features of system water – rock – gas – living material and character of interaction of hydrosphere with the other spheres of the Earth. It is necessary to concentrate the development of endogenous hy-drogeology fundamentals with the study of silicate karst on investigation of “white and black smokers”, the structure and isotope composition of water in different phase condi-tions, and on modeling of situation in hydrometagenese zone. It will support the development of geotechnology and providing the humanity with mineral and energetic resources in future.

  17. Factors affecting public-supply well vulnerability in two karst aquifers.

    Science.gov (United States)

    Musgrove, MaryLynn; Katz, Brian G; Fahlquist, Lynne S; Crandall, Christy A; Lindgren, Richard J

    2014-09-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearby monitoring wells and regional PSWs. Geochemistry results were integrated with age tracers, flow modeling, and depth-dependent data to refine aquifer conceptual models and to identify factors that affect contaminant movement to PSWs. The oxic Edwards aquifer is vertically well mixed at the selected PSW/wellfield, although regionally the aquifer is geochemically variable downdip. The mostly anoxic Upper Floridan aquifer is affected by denitrification and also is geochemically variable with depth. In spite of considerable differences in geology and hydrogeology, the two aquifers are similarly vulnerable to anthropogenic contamination. Vulnerability in studied PSWs in both aquifers is strongly influenced by rapid karst flowpaths and the dominance of young (aquifers (nitrate, atrazine, deethylatrazine, tetrachloroethene, and chloroform). Specific consideration of water-quality protection efforts, well construction and placement, and aquifer response times to land-use changes and contaminant loading are discussed, with implications for karst groundwater management. © 2014 The Authors. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

  18. The role of evaporites in the formation of gems during metamorphism of carbonate platforms: a review

    Science.gov (United States)

    Giuliani, Gaston; Dubessy, Jean; Ohnenstetter, Daniel; Banks, David; Branquet, Yannick; Feneyrol, Julien; Fallick, Anthony E.; Martelat, Jean-Emmanuel

    2018-01-01

    The mineral and fluid inclusions trapped by gemstones during the metamorphism of carbonate platform successions are precious markers for the understanding of gem genesis. The nature and chemical composition of inclusions highlight the major contribution of evaporites through dissolution or fusion, depending on the temperature of formation from greenschist to granulite facies. The fluids are highly saline NaCl-brines circulating either in an open system in the greenschist facies (Colombian and Afghan emeralds) and with huge fluid-rock metasomatic interactions, or sulphurous fluids (ruby, garnet tsavorite, zoisite tanzanite and lapis-lazuli) or molten salts formed in a closed system with a low fluid mobility (ruby in marble) in the conditions of the amphibolite to granulite facies. These chloride-fluoride-sulphate ± carbonate-rich fluids scavenged the metals essential for gem formation. At high temperature, the anions SO4 2-, NO3 -, BO3 - and F- are powerful fluxes which lower the temperature of chloride- and fluoride-rich ionic liquids. They provided transport over a very short distance of aluminium and/or silica and transition metals which are necessary for gem growth. In summary, the genetic models proposed for these high-value and ornamental gems underline the importance of the metamorphism of evaporites formed on continental carbonate shelves and emphasise the chemical power accompanying metamorphism at moderate to high temperatures of evaporite-rich and organic matter-rich protoliths to form gem minerals.

  19. Techniques to better understand complex epikarst hydrogeology and contaminant transport in telogenetic karst settings

    Science.gov (United States)

    The movement of autogenic recharge through the shallow epikarstic zone in soil-mantled karst aquifers is important in understanding recharge areas and rates, groundwater storage, and contaminant transport processes. The groundwater flow in agricultural karst areas, such as Kentucky’s Pennyroyal Plat...

  20. Transport of free and particulate-associated bacteria in karst

    Science.gov (United States)

    Mahler, B. J.; Personné, J.-C.; Lods, G. F.; Drogue, C.

    2000-12-01

    Karst aquifers, because of their unique hydrogeologic characteristics, are extremely susceptible to contamination by pathogens. Here we present the results of an investigation of contamination of a karst aquifer by fecal indicator bacteria. Two wells intercepting zones with contrasting effective hydraulic conductivities, as determined by pump test, were monitored both during the dry season and in response to a rain event. Samples were also collected from the adjacent ephemeral surface stream, which is known to be impacted by an upstream wastewater treatment plant after rainfall. Whole water and suspended sediment samples were analyzed for fecal coliforms and enterococci. During the dry season, pumping over a 2-day period resulted in increases in concentrations of fecal coliforms to greater than 10,000 CFU/100 ml in the high-conductivity well; enterococci and total suspended solids also increased, to a lesser degree. Toward the end of the pumping period, as much as 50% of the fecal coliforms were associated with suspended sediment. Irrigation of an up-gradient pine plantation with primary-treated wastewater is the probable source of the bacterial contamination. Sampling after a rain event revealed the strong influence of water quality of the adjacent Terrieu Creek on the ground water. Bacterial concentrations in the wells showed a rapid response to increased concentrations in the surface water, with fecal coliform concentrations in ground water ultimately reaching 60,000 CFU/100 ml. Up to 100% of the bacteria in the ground water was associated with suspended sediment at various times. The results of this investigation are evidence of the strong influence of surface water on ground water in karst terrain, including that of irrigation water. The large proportion of bacteria associated with particulates in the ground water has important implications for public health, as bacteria associated with particulates may be more persistent and more difficult to inactivate. The

  1. FATE AND TRANSPORT OF PETROLEUM RELEASED FROM UNDERGROUND STORAGE TANKS in Areas of Karst Topography

    Science.gov (United States)

    The study determines the transport and ultimate fate of petroleum products within a region of karst geomorphology. The paper entails a complete literature review, including references that pertain to contaminant transport within karst aquifers

  2. Karst bare slope soil erosion and soil quality: a simulation case study

    OpenAIRE

    Q. Dai; Z. Liu; H. Shao; Z. Yang

    2015-01-01

    The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1), no ...

  3. Metode Tracer Test untuk Mencari Hubungan Antar Sistem Sungai Bawah Tanah Di Akuifer Karst

    Directory of Open Access Journals (Sweden)

    Harjito Harjito

    2015-08-01

    Full Text Available Problem yang umum dijumpai di kawasan karst adalah mengenai ketersediaan air, mengingat kondisi hidrologi kawasan karst yang berbeda dengan kawasan lain. Ditinjau dari sisi lain, masyarakat di sekitar kawasan rencana perluasan eksploitasi masih memanfaatkan mata air yang daerah tangkapannya berasal dari perbukitan batu gamping untuk memenuhi kebutuhan air domestik dan irigasi pertanian. Dengan demikian, perlu adanya penelitian hidrologi karst lebih lanjut terutama mengenai keberadaan sistem jaringan yang saling terhubung di dalam kawasan rencana perluasan eksploitasi dan sekitarnya. Studi ini diharapkan dapat menjadi pertimbangan terhadap kebijakan yang akan diambil sebagai upaya untuk dapat melakukan pengelolaan potensi tersebut sebaik-baiknya. Tracer test dilakukan sebagai bentuk follow-up dari survei gua dan sinkhole yang ada di sekitar area tambang. Tracer test dilakukan untuk mengetahui konektivitas aliran pada sistem gua berair dan mata air Cipintu. Berdasarkan hasil penelitian potensi debit air di Mata air Cipintu sebesar 18,55 liter/s dan mengindikasikan adanya konektivitas antara gua berair dengan Mata air Cipintu. Kata kunci : karst, hidrologi, tracer test, eksploitasi

  4. Imaging of underground karst water channels using an improved multichannel transient Rayleigh wave detecting method.

    Science.gov (United States)

    Zheng, Xuhui; Liu, Lei; Sun, Jinzhong; Li, Gao; Zhou, Fubiao; Xu, Jiemin

    2018-01-01

    Geological and hydrogeological conditions in karst areas are complicated from the viewpoint of engineering. The construction of underground structures in these areas is often disturbed by the gushing of karst water, which may delay the construction schedule, result in economic losses, and even cause heavy casualties. In this paper, an innovative method of multichannel transient Rayleigh wave detecting is proposed by introducing the concept of arrival time difference phase between channels (TDP). Overcoming the restriction of the space-sampling law, the proposed method can extract the phase velocities of different frequency components from only two channels of transient Rayleigh wave recorded on two adjacent detecting points. This feature greatly improves the work efficiency and lateral resolution of transient Rayleigh wave detecting. The improved multichannel transient Rayleigh wave detecting method is applied to the detection of karst caves and fractures in rock mass of the foundation pit of Yan'an Road Station of Guiyang Metro. The imaging of the detecting results clearly reveals the distribution of karst water inflow channels, which provided significant guidance for water plugging and enabled good control over karst water gushing in the foundation pit.

  5. Karst bare slope soil erosion and soil quality: a simulation case study

    OpenAIRE

    Q. Dai; Z. Liu; H. Shao; Z. Yang

    2015-01-01

    The influence on soil erosion by different bedrock bareness ratios, different rainfall intensities, different underground pore fissure degrees and rainfall duration are researched through manual simulation of microrelief characteristics of karst bare slopes and underground karst crack construction in combination with artificial simulation of rainfall experiment. The results show that firstly, when the rainfall intensity is small (30 and 50 mm h−1), no bottom load loss is pro...

  6. Karst Depression Detection Using ASTER, ALOS/PRISM and SRTM-Derived Digital Elevation Models in the Bambuí Group, Brazil

    Directory of Open Access Journals (Sweden)

    Osmar Abílio de Carvalho

    2013-12-01

    Full Text Available Remote sensing has been used in karst studies to identify limestone terrain, describe exokarst features, analyze karst depressions, and detect geological structures important to karst development. The aim of this work is to investigate the use of ASTER-, SRTM- and ALOS/PRISM-derived digital elevation models (DEMs to detect and quantify natural karst depressions along the São Francisco River near Barreiras city, northeast Brazil. The study area is a karst landscape characterized by karst depressions (dolines, closed depressions in limestone, many of which contain standing water connected with the ground-water table. The base of dolines is typically sealed with an impermeable clay layer covered by standing water or herbaceous vegetation. We identify dolines by combining the extraction of sink depth from DEMs, morphometric analysis using GIS, and visual interpretation. Our methodology is a semi-automatic approach involving several steps: (a DEM acquisition; (b sink-depth calculation using the difference between the raw DEM and the corresponding DEM with sinks filled; and (c elimination of falsely identified karst depressions using morphometric attributes. The advantages and limitations of the applied methodology using different DEMs are examined by comparison with a sinkhole map generated from traditional geomorphological investigations based on visual interpretation of the high-resolution remote sensing images and field surveys. The threshold values of the depth, area size and circularity index appropriate for distinguishing dolines were identified from the maximum overall accuracy obtained by comparison with a true doline map. Our results indicate that the best performance of the proposed methodology for meso-scale karst feature detection was using ALOS/PRISM data with a threshold depth > 2 m; areas > 13,125 m2 and circularity indexes > 0.3 (overall accuracy of 0.53. The overall correct identification of around half of the true dolines suggests

  7. ERT, GPR, InSAR, and tracer tests to characterize karst aquifer systems under urban areas: The case of Quebec City

    Science.gov (United States)

    Martel, Richard; Castellazzi, Pascal; Gloaguen, Erwan; Trépanier, Luc; Garfias, Jaime

    2018-06-01

    Urban infrastructures built over karst settings may be at risk of collapse due to hydro-chemical erosion of underlying rock structures. In such settings, mapping cave networks and monitoring ground stability is important to assure civil safety and guide future infrastructure development decisions. However, no technique can directly and comprehensively map these hydrogeological features and monitor their stability. The most reliable method to map a cave network is through speleological exploration, which is not always possible due to restrictions, narrow corridors/passages, or high water levels. Borehole drilling is expensive and is often only performed where the presence of karsts is suggested by other techniques. Numerous indirect and cost-effective methods exist to map a karst flow system, such as geophysics, geodesy, and tracer tests. This paper presents the outcomes from a challenging application in Quebec City, Canada, where a multidisciplinary approach was designed to better understand the groundwater dynamics and cave paths. Two tracer tests in groundwater flowing through the cave system indicated that water flows along an approximately straight path from the sinking stream to the spring. It also suggests the presence of a parallel flow path close to the one already partially mapped. This observation was confirmed by combining Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) techniques, and ultimately by observing voids in several boreholes drilled close to the main cave path. Lowering the water levels at the suspected infiltration zone and inside the karst, the infiltration cracks were identified and the hydraulic link between them was confirmed. In fact, almost no infiltration occurs into the karst system when the water level at the sinking stream drops below a threshold level. Finally, SAR interferometry (InSAR) using RADARSAT-2 images detected movements on few buildings located over a backfilled sinkhole intercepted by the karst

  8. Runoff response to climate change and human activities in a typical karst watershed, SW China

    Science.gov (United States)

    Xu, Yan; Wang, Shijie; Shu, Dongcai; Tian, Yichao

    2018-01-01

    problem in the karst region and for the sustainable development of the drainage basin. PMID:29494602

  9. Negative effects of land-use changes in the karst setting of Apulia, southern Italy

    Science.gov (United States)

    Parise, Mario

    2010-05-01

    Apulia is an almost entirely carbonate region in south-eastern Italy, representing the heel of the boot-shaped Italian peninsula. Due to its location in the heart of the Mediterranean basin, and its geographical configuration, which in some way connects the Italian territory to the eastward lands, it had a long history of human settlements, as shown by the many remarkable prehistoric findings that have been recorded in this area during the last century. The flatness of the region, derived from the geologic origin of Apulia as the undeformed foreland of the Southern Apenninic Chain of Italy, together with its NW-SE oriented peninsula configuration and the long coastlines, are at the origin of the good-continuity occupation by man during the different phases of human history. The original karst landscape, characterized by absence of surface runoff, due to rapid infiltration of surface water into the network of karst conduits and fissures within the carbonate rock mass, was with time modified by man. Agriculture initially developed in the narrow strips of land where the presence of residual deposits (terre rosse) allowed the establishment of thin soil layers, and/or in small depressions where water was able to be kept for a longer time within the epikarst. Outside of these sites, the karst landscape typically consisted of stony plateaus and subdued rounding hills. To gain further space to agricultural practices, part of the surrounding stony areas was cleared of rocks: the latter were extracted by hand, and used to build dry stone walls to delimitate the properties, and/or to act as a barrier to soil erosion or to work as terrace walls in the sectors with higher gradients. At the same time, extraction and re-use of carbonate rocks originated some of the typical rural architecture common in Apulia, from "trulli" to "pagliare" and, later on, to "masserie" (the old countryside mansions). In the last decades of XX century, thanks to the use of modern technologies and

  10. Investigation of karst collapse based on 3-D seismic technique and DDA method at Xieqiao coal mine, China

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Jian-Ping; Chen, Zhong-Hui [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Institute of Rock Mechanical and Fractals, China University of Mining and Technology, Beijing 100083 (China); Peng, Su-Ping; Li, Yong-Jun [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Xie, He-Ping [Institute of Rock Mechanical and Fractals, China University of Mining and Technology, Beijing 100083 (China)

    2009-06-01

    Karst collapse is a serious geological problem in most of the coal mines in the north of China, but recently it has been found in the south as well. The present study is aimed at investigating subsidence mechanism and deformation field of a karst collapse column at Xieqiao, in the south of China. A method of three-dimensional (3-D) seismic technique has been successful in exploring the spatial morphology of the karst collapse at Xieqiao, and the discontinuous deformation analysis (DDA) method is used to calculate the deformation field and analyze the subsidence mechanism. The results indicated that DDA could approximately simulate and back analyze the subsidence process and strata deformation fields. The subsidence processes of the collapse column depend on the sizes of the karst caves. With the continuous expansion of the karst caves, a semi-elliptic stress field, local separation strata and fracture zone will be formed around the karst cave. Moreover, they will gradually expand upwards along the vertical direction. The paper also indicates that the subsidence failure stage may trigger a sudden collapse of the karst column because of the sudden energy release. Also, it will make a great impact on the vicinity working face so as to cause a rock burst. The effects of the friction angle of rock strata on the subsidence mechanism were reported firstly based on DDA. (author)

  11. Overview of the geophysical studies in the Dead Sea coastal area related to evaporite karst and recent sinkhole development

    Directory of Open Access Journals (Sweden)

    Mikhail G. Ezersky

    2017-05-01

    Full Text Available Since the early 80s, a progressively increasing number of sinkholes appeared along the Dead Sea coastal line. It has been found that their appearance is strongly correlating with the lowering of the Dead Sea level taking place with the rate of approximately 1 m/yr. Location of areas affected by sinkhole development corresponds to location of the salt formation deposited during the latest Pleistocene, when the Lake Lisan receded to later become the Dead Sea. Water flowing to the Dead Sea from adjacent and underlying aquifers dissolves salt and creates caverns that cause ground subsidence and consequent formation of sinkholes. Before subsidence, these caverns are not visible on the surface but can be investigated with surface geophysical methods. For that, we applied Surface Nuclear Magnetic Resonance (SNMR, Transient Electromagnetic (TEM Seismic refraction and reflection, Multichannel Analysis of Surface waves (MASW, microgravity and magnetic surveys and their combinations. Our geophysical results allowed us to locate the salt formation and to detect caverns in salt thus contributing to better understanding sinkhole development mechanisms. Comparison of sinkhole appearance along the western DS shore derived from the recent database (2017 shows that predictions made on the base of geophysical data (2005-2008 are now confirmed thus demonstrating efficiency of our study. In this paper, we briefly present a summary of up to date knowledge of the geology and hydrogeology of Dead Sea basin, of the physical properties of the salt rock and the most popular models explaining mechanisms of sinkhole development. We also share our experience gained during geophysical studies carried out in the framework of national and international research projects in this area for the last 20 years.

  12. Karst groundwater: a challenge for new resources

    Science.gov (United States)

    Bakalowicz, Michel

    2005-03-01

    Karst aquifers have complex and original characteristics which make them very different from other aquifers: high heterogeneity created and organised by groundwater flow; large voids, high flow velocities up to several hundreds of m/h, high flow rate springs up to some tens of m3/s. Different conceptual models, known from the literature, attempt to take into account all these particularities. The study methods used in classical hydrogeology—bore hole, pumping test and distributed models—are generally invalid and unsuccessful in karst aquifers, because the results cannot be extended to the whole aquifer nor to some parts, as is done in non-karst aquifers. Presently, karst hydrogeologists use a specific investigation methodology (described here), which is comparable to that used in surface hydrology. Important points remain unsolved. Some of them are related to fundamental aspects suc h as the void structure - only a conduit network, or a conduit network plus a porous matrix -, the functioning - threshold effects and non-linearities -, the modeling of the functioning - double or triple porosity, or viscous flow in conduits - and of karst genesis. Some other points deal with practical aspects, such as the assessment of aquifer storage capacity or vulnerability, or the prediction of the location of highly productive zones. Los acuíferos kársticos tienen características originales y complejas que los hacen muy diferentes de otros acuíferos: alta heterogeneidad creada y organizada por el flujo de agua subterránea, espacios grandes, velocidades altas de flujo de hasta varios cientos de m/h, manantiales con ritmo alto de flujo de hasta algunas decenas de m3/s. Diferentes modelos conceptuales que se conocen en la literatura tratan de tomar en cuenta todas estas particularidades. Los métodos de estudio usados en hidrogeología clásica- pozos, pruebas de bombeo y modelos distribuidos- son generalmente inválidos y no exitosos en acuíferos kársticos, debido a que

  13. Discussion on karst tunnel water inrush and prevention%谈岩溶隧道突水与防治

    Institute of Scientific and Technical Information of China (English)

    张高青

    2016-01-01

    简要概括了岩溶的定义,从地质、气象、施工三方面,分析了影响岩溶隧道突水的主要因素,论述了岩溶隧道突水造成的危害,提出了岩溶隧道突水的预防与治理措施,为岩溶隧道突水防治提供理论依据。%This paper briefly generalized the definition of karst,from the geology,meteorology,construction three aspects,analyzed the main fac-tors influence of karst tunnel water inrush,discussed the disasters caused by karst tunnel water inrush,put forward the prevention and treatment measures of karst tunnel water inrush,provided theoretical basis for prevention and control of karst tunnel water inrush.

  14. Hydrogeological controls of variable microbial water quality in a complex subtropical karst system in Northern Vietnam

    Science.gov (United States)

    Ender, Anna; Goeppert, Nadine; Goldscheider, Nico

    2018-05-01

    Karst aquifers are particularly vulnerable to bacterial contamination. Especially in developing countries, poor microbial water quality poses a threat to human health. In order to develop effective groundwater protection strategies, a profound understanding of the hydrogeological setting is crucial. The goal of this study was to elucidate the relationships between high spatio-temporal variability in microbial contamination and the hydrogeological conditions. Based on extensive field studies, including mapping, tracer tests and hydrochemical analyses, a conceptual hydrogeological model was developed for a remote and geologically complex karst area in Northern Vietnam called Dong Van. Four different physicochemical water types were identified; the most important ones correspond to the karstified Bac Son and the fractured Na Quan aquifer. Alongside comprehensive investigation of the local hydrogeology, water quality was evaluated by analysis for three types of fecal indicator bacteria (FIB): Escherichia coli, enterococci and thermotolerant coliforms. The major findings are: (1) Springs from the Bac Son formation displayed the highest microbial contamination, while (2) springs that are involved in a polje series with connections to sinking streams were distinctly more contaminated than springs with a catchment area characterized by a more diffuse infiltration. (3) FIB concentrations are dependent on the season, with higher values under wet season conditions. Furthermore, (4) the type of spring capture also affects the water quality. Nevertheless, all studied springs were faecally impacted, along with several shallow wells within the confined karst aquifer. Based on these findings, effective protection strategies can be developed to improve groundwater quality.

  15. Integrating remote sensing with GIS-based multi-criteria evaluation approach for Karst rocky desertification assessment in Southwest of China

    International Nuclear Information System (INIS)

    Zhang, Z; Xu, W; Zhou, W; Zhang, L; Xiao, Y; Ouyang, Z; Ou, X

    2014-01-01

    The increasing exploitation of Karst resources is leading to severe environmental impacts, as Karst frequently occurs in the most fragile and vulnerable environments. This paper presents a multi-criteria evaluation (MCE) approach in a spatial context to support Karst rocky desertification (KRD) assessment by integrating remote sensing data with GIS. The study area is located in Wenshan Prefecture, Yunnan Province, Southwest of China. Criteria and impact factors for KRD first were identified and weighted through pairwise comparison method. A GIS fuzzy set membership function was then used to generate gradient effects of each criterion, and a clustering method based on K-mean algorithms was used to classify KRD into several descending rank zones (or levels). Both ROC and error matrix assessments indicated that the MCE approach is better than the NDVI approach. In addition, we found it is useful to integrate the topographic and human disturbance factors into KRD mapping and assessment, compared with most of the previous KRD assessment studies mainly focused on developing vegetation or land cover information in karst regions by using remote sensing alone. Furthermore, the integrated MCE approach is robust, flexible, and easy to be implemented. It also explicitly includes the quantitative and qualitative information, for instance, opinions of decision makers and experts as well as characteristics of the landscape

  16. Strategy for definition and protection of east Tennessee karst groundwater basins

    International Nuclear Information System (INIS)

    Rubin, P.A.; Lemiszki, P.J.; Poling, R.S.

    1992-01-01

    This paper describes and gives suggestions for protecting the bedrock geology of eastern Tennessee which is typical of the southern Appalachian Valley and Ridge province. Carbonate beds (limestones and dolomites) of the Knox and Chickamauga Groups are bounded by non-carbonate beds, most of which strike northeast and dip steeply (10 degrees--45 degrees) to the southeast. The carbonate aquifers are maturely karstified and are extremely vulnerable to contaminant infiltration, thus necessitating appropriate land use planning focused on their environmental sensitivity. Urban expansion is resulting in greater land development in karst regions. Planned and existing activities produce wastes that may potentially leach into underlying karst systems. This waste may flow rapidly and untreated for many miles along strike. The potential degradation of aquifers and receiving streams due to the cumulative waste loading of numerous small enterprises may be more environmentally destructive than a few hazardous waste sites. Costs to remediate contaminated water supplies and streams can be in the millions of dollars versus the substantially lower costs of prudent land use planning

  17. Ground Radiometric Method as a Tool for Determining the Surface Boundary of a Buried Bauxitic Karst

    Directory of Open Access Journals (Sweden)

    Kamal Kareem Ali

    2011-12-01

    Full Text Available Forty two ground radiometric measurements along nine traverses within a rectangular network area were taken across a bauxitic karst within the Ubaid Formation (Lower Jurassic in the Western Desert of Iraq. A 4-Channel Gamma Ray Spectrometer (GAD-6 with sodium iodide NaI (Tl crystal (GSP-4S was used in the field to measure the total radioactivity of the surface soil. Soil samples collected from the surface at each measurement point and core samples collected from a test well penetrating the karst were analyzed by Gamma ray spectrometer. The main objective of this study was to detect the hidden bauxitic karst and determine its surface boundary. The radioactivity on the surface of the karst was ranging between 60 and 80 count per second (c/s, while the background radioactivity of the Ubaid Formation, which hosts the karst, was ranging between 100 and150 c/s. Chemical weathering, especially dissolution and leaching moved uranium (238U and thorium(232Th from the overburden downward. Accordingly, these elements have been adsorbed on the surface of clay minerals and bauxite buried at a depth of about 5m causing enrichment with radioactivity. The leached overburden lack radioelements, so its radioactivity was less than background radioactivity level. The gamma ray spectroanalysis showed that the radioactivity of 238U and 232Th in the overburden was 0.5 and 3 Bq/Kg, whereas, in the bauxite and flint clay bed, it was 240 and 160 Bq/Kg respectively. Based on the radioactivity anomaly contrast on the surface, an isorad map was plotted and the karst diameter which represents low anomaly was determined to be ranging from 150 to 200m. The current study demonstrates that the ground radiometric method is quite useful for detecting the bauxitic karst and inferring its surface boundaries.

  18. Analysis of the karst aquifer structure of the Lamalou area (Herault, France) with ground penetrating radar

    International Nuclear Information System (INIS)

    Al-Fares, W.; Bakalowicz, M.; Guerin, R.; Dukhan, M.

    2004-01-01

    The study site at Lamalou karst spring Hortus karst plateau) is situated 40 km north of Montpellier in France. It consists of a limestone plateau, drained by a karst conduit discharging as a spring. This conduit extends for a few dozen meters in fractured and karstified limestone rocks, 15 to 70 m below the surface. The conduit is accessible from the surface. The main goal of this study is to analyze the surface part of the karst and to highlight the karstic features and among them the conduit, and to test the performances of ground penetrating radar (GPR) in a karstic environment. This method thus appears particularly well adapted to the analysis of the near-surface (<30 m in depth) structure of a karst, especially when clayey coating or soil that absorbs and attenuates the radar is rare and discontinuous. A GPR pulse EKKO 100 (Sensors and Software) was used on the site with a 50 MHz antenna frequency. The results highlight structures characterizing the karstic environment: The epikarst, bedding planes, fractured and karstified zones, compact and massive rock and karrens, a typical karst landform. One of the sections revealed in detail the main conduit located at a depth of 20 m, and made it possible to determine its geometry. This site offers possibilities of validation of GPR data by giving direct access to the karstic conduit and through two cored boreholes. These direct observations confirm the interpretation of all the GPR sections. (author

  19. Groundwater flow and potential effects on evaporite dissolution in the Paradox Basin, SE Utah

    Science.gov (United States)

    Reitman, N.; Ge, S.; Mueller, K. J.

    2012-12-01

    is measured in higher altitude samples. These measurements are consistent with high altitude samples representing precipitation and low altitude samples representing shallow groundwater. Location and altitude of springs sampled in this study, as well as those recorded by earlier studies, were used to create a potentiometric surface map in GIS. From the map, water flow direction is inferred to flow mostly from the Abajo Mountains in the southeast towards the Colorado River in the northwest. A transient groundwater flow and solute transport model is developed for a 2-D cross section from the Abajo Mountains in the SE to the Colorado River in the NW. Recharge is applied in the southeast, driving water flow towards the northwest. Most discharge flows into the Colorado River, primarily via seepage through cliff faces. Surface discharge occurs in topographic lows. The flow and solute concentration patterns from the model are generally consistent with field data. Evaporite dissolution varies laterally depending on groundwater flow pattern. Deep groundwater flow patterns and pore pressure data from the model will contribute to an understanding of subsurface salt dissolution and active salt tectonics in the study region. Additionally, the results of this study will help land and water managers protect scarce freshwater resources in this arid desert region.

  20. Revison of an Atheloptic Visean Trilobite Association in the Moravian Karst (Czech Republic

    Directory of Open Access Journals (Sweden)

    Rak Štěpán

    2015-01-01

    Full Text Available Recently two new trilobite occurrences were discovered during geological mapping of fossiliferous shales of the Březina Formation around the village of Březina in the Moravian Karst (Czech Republic. The newly discovered localities are extraordinary because of the unexpected occurrence of articulated trilobite exoskeletons associated with brachiopods including supporting spines. The new atheloptic association of Mississippian trilobites is described for the first time from the Moravian Karst.

  1. Evaporite deposition in a shallow perennial lake, Qaidam basin, western China

    Energy Technology Data Exchange (ETDEWEB)

    Schubel, K.A.; Lowenstein, T.K. (SUNY, Binghampton, NY (United States)); Spencer, R.J. (Univ. of Calgary, Alberta (Canada)); Pengxi, Z. (Institute of Salt Lakes, Xining (China))

    1991-03-01

    Evaporites accumulate in ephemeral saline-pans, shallow perennial lakes or lagoons, and deep perennial systems. Continuous brine trench exposures of Holocene evaporites from the Qaidam basin provide criteria for the recognition of shallow perennial lake sediments. Based on Landsat photographs, lateral extent of beds (at least 7 km), and sequence thicknesses (maximum 2.5 m), the paleolake is interpreted to have been less than 2.5 m deep and at least 120 km{sup 2} in area. Sediments consist of laminated siliciclastic mud overlain by mud-halite couplets (mm- to cm-scale layers), which represent one vertical shallowing- and concentrating-upwards sequence. The basal laminite marks the onset of deposition in this shallow perennial paleolake. Syndepositional halite textures and fabrics in the overlying mud-halite couplets include cumulates, rafts, and chevrons, draped by mud laminae, and halite layers truncated by horizontal dissolution surfaces (increasing in frequency upwards). Paleolake brines, determined from fluid inclusion melting temperatures, are Na-Mg-Cl-rich and evolve from 0.84 m Mg{sup 2} to 1.52 m Mg{sup 2+} (near the surface). Combinations of the following criteria may be used for the recognition of shallow, nonstratified, perennial lake sediments: lateral continuity of layers; muds undisrupted by subaerial exposure; vertical bottom-growth of halite; halite layers conformably overlain by mud; halite layers truncated by nonuniformly spaced horizontal dissolution surfaces; erosional scours and channels filled with cross-laminated gypsum, halite, and siliciclastic sand and mud; and salinity fluctuations over small stratigraphic intervals within an overall concentrating-upwards sequence.

  2. [Distribution of 137Cs and relative influencing factors on typical karst sloping land].

    Science.gov (United States)

    Zhang, Xiao-Nan; Wang, Ke-Lin; Zhang, Wei; Chen, Hong-Song; He, Xun-Yang; Zhang, Xin-Bao

    2009-11-01

    Based on the field survey and the analysis of a large number of soil samples, the distribution of 137 Cs and its influencing factors were studied using 137 Cs tracer technology on typical karst sloping land. The results indicate that the distribution of 137 Cs in soil profile in karst areas show the similar characteristics as that in non-karst areas, fitted an exponential pattern in forest soils and a uniform pattern in cultivated soils. In the sinkhole points in karst areas, 137 Cs exists in deep soil layers and its specific activity vary from 1.7 to 3.3 Bq/kg in soil layers above 45cm, suggesting the existing soil around karst sinkhole is mainly formed by the accumulation of erosion materials. The 137 Cs specific activity in the soil from two rock cracks are 16.8 Bq/kg and 37.6 Bq/kg respectively, which are much higher than that in the soil around the rock, this phenomenon indicates that bare rock is an important influencing factor for 137 Cs spatial movement. With the increment of altitude, the 137 Cs area activity exhibits an irregular fluctuation and evident spatial heterogeneity. On the forest land, the 137 Cs area activities which range from 299.4 to 1 592.6 Bq/m2 are highly positively correlated with the slope gradient and positively correlated with the altitude; while on the cultivated land, the 137 Cs area activities which range from 115.8 to 1478.6 Bq/m2 are negatively correlated with the slope gradient but negatively correlated with the altitude. Topography, geomorphology and human disturbance intensity are the key factors influencing 137 Cs spatial distribution.

  3. SWAT-based streamflow and embayment modeling of Karst-affected Chapel branch watershed, South Carolina

    Science.gov (United States)

    Devendra Amatya; M. Jha; A.E. Edwards; T.M. Williams; D.R. Hitchcock

    2011-01-01

    SWAT is a GIS-based basin-scale model widely used for the characterization of hydrology and water quality of large, complex watersheds; however, SWAT has not been fully tested in watersheds with karst geomorphology and downstream reservoir-like embayment. In this study, SWAT was applied to test its ability to predict monthly streamflow dynamics for a 1,555 ha karst...

  4. VALUASI EKONOMI BIODIVERSITY KARS: STUDI KASUS VALUASI EKONOMI KAWASAN KARS MAROS, SULAWESI SELATAN (Economic Valuation of Karst Biodiversity: A Case Study of Karst Region in Maros, South Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Gustami Gustami

    2002-07-01

    Maros, Muhammadiyah University and Hassanudin University in Makassar. A travel expenditure approach was firstly assessed to determine the direct use value of recreation activities. Indirect value determination abou the existence of karst region including its forest was conducted based lor the value of its function as water resources and prevention of flood and land slide. The preservation value of karst region was determined by computing visitors willingness to pay for butterfly conservation, environmental improvement, amenity, and also the number of visitors. Based on the result of the analysis, the total economic value consisted of the direct use value, indirect use value, and non-use value which formed the preservation value amounting Rp. 639.556.607,830,-. Even though there other economic values which have not been assessed, this study has addressed some parts of economic values of a karst region which was developed by both local and outside people who enjoy the classical tropical karst of Maros.

  5. Isotopic study of Karst water

    International Nuclear Information System (INIS)

    Leskovsek-Sefman, H.

    1985-01-01

    Measurement of the isotopic composition of water formed part of an extended investigation of the water drainage system in the Slovenian Karst. These studies were planned to complement geological and speleological investigations which are already being performed in this area, with the knowledge of the mechanism of changes in the isotopic composition of water in the natural environment on some smaller locations, Planina cave near Postojna where the vertical percolation of meteoric water through the karstified carbonate ceiling was studied and the water catchment areas of some small rivers, Ljubljanica, Rizana and Idrijca. Mass spectrometric investigations of the isotopic composition of some elements ( 18 O, D, 13 C and T) in water and in dissolved carbonates, as well as the isotopic composition of 18 O and 13 C in cave carbonates were performed. The results allow to conclude that the waters in karst aquifers in spite of producing the homogenisation to a great extent, qualitative determination of the retention time and of the prevailing sources for some springs and surface and underground water flows is nevertheless possible. The isotopic composition of 18 O in water and of 18 O and 13 C in dissolved carbonates depends on climatic conditions and on denudation processes. The investigation of cave carbonates revealed that they have different isotopic compositions of 18 O and 13 C because of different locations and also different ages

  6. Karst geomorphology and hydrology at the Campania - Basilicata border (southern Apennines of Italy)

    Science.gov (United States)

    Farfan Gonzalez, H.; Parise, M.

    2009-04-01

    This paper describes the main karst geomorphological and hydrological features of the area at the boundary between the Campania and Basilicata regions, in the southern Apennines of Italy. Even not far from the most important karst area of southern Italy (the Alburni Massif, hosting hundreds of caves, with very complex subterranean systems that have been extensively explored in the last 50 years), this sector has never been object of detailed karstic studies. Geologically, it shows a carbonate bedrock consisting of Cretaceous limestones and dolomites, in tectonic contact with terrigenous deposits of Miocene age. The territory is an active seismogenic zone, as testified by the November 23, 1980, earthquake that hit this part of southern Italy with a 6.8 magnitude, causing over 2,700 victims and destroying several small towns in the two regions. In 2007, within the framework of joint projects between the Italian Speleological Society (SSI) and the Cuban Speleological Society (SEC), a scientific and speleological expedition was carried out in a sector of this area. The efforts produced during the expedition, and in the preceeding phases as well, resulted in discovery, survey and documentation of 62 caves, and in supporting the progresses of the exploration activities in the main karst system in the area, a complex of two caves that reach a maximum depth of 123 meters and an overall length of 1,8 km. At the surface, a variety of karst landforms is recognizable. The main carbonate ridges show several orders of palaeosurfaces, located at different heights above sea level. Bounded by fault lines or fault line scarps, they present variable extension, the highest surfaces showing a much better continuity. On the Campanian side, several sinkholes are also present, some of which opened in the aftermath of the 1980 earthquake. The same event caused in Basilicata the formation of several caves of structural origin, controlled in their development by tectonics and extremely

  7. Eogenetic karst, glacioeustatic cave pools and anchialine environments on Mallorca Island: a discussion of coastal speleogenesis.

    Directory of Open Access Journals (Sweden)

    Angel Ginès

    2007-07-01

    Full Text Available Coastal karst is characterized by special geomorphologic and hydrodynamic conditions as well as by peculiar sedimentary, geochemical, and biospeleological environments. Generally, the more distinctive karstic features produced near the coastline are strongly influenced by sea-level changes, which generate a broad set of interactions between littoral processes and karst development. The glacioeustatic rises and falls of sea level affected the littoral karst in different ways, namely: vertical and horizontal shifts in the shoreline position, changes in elevation of the local water table, and vertical displacements of the halocline. Most eogenetic karsts have been subjected over long time spans to repeated changes of a variety of vertically-zoned geochemical environments: vadose, phreatic meteoric-water, brackish mixing-waters and even marine water. Many coastal caves appear to be passively drowned by Holocene sea-level rise, and to contain glacioeustatic pools of varied size where the current water table intersects formerly air-filled chambers or passages. These coastal phreatic waters are controlled by sea level and fluctuate with tides. Significantly, features such as phreatic speleothems that are able to record ancient sea levels occur closely associated to the surface of the pools. The cave pools are brackish or even marine anchialine environments that contain remarkable communities of troglobitic stygofauna. All of these aspects can be studied in detail along the southern and eastern coast of Mallorca Island owing to the widespread outcrop of Upper Miocene calcarenites, in which the development of eogenetic karst features started approximately 6 Ma ago, at the end of Messinian times. Some outstanding coastal caves result and include the celebrated Coves del Drac (explored by E.A. Martel in 1896, the labyrinthine Cova des Pas de Vallgornera (more than 30 km in length and the recently explored Cova de sa Gleda (whose submerged passages exceed

  8. Improved 2-D resistivity imaging of features in covered karst terrain with arrays of implanted electrodes

    Science.gov (United States)

    Kiflu, H. G.; Kruse, S. E.; Harro, D.; Loke, M. H.; Wilkinson, P. B.

    2013-12-01

    Electrical resistivity tomography is commonly used to identify geologic features associated with sinkhole formation. In covered karst terrain, however, it can be difficult to resolve the depth to top of limestone with this method. This is due to the fact that array lengths, and hence depth of resolution, are often limited by residential or commercial lot dimensions in urban environments. Furthermore, the sediments mantling the limestone are often clay-rich and highly conductive. The resistivity method has limited sensitivity to resistive zones beneath conductive zones. This sensitivity can be improved significantly with electrodes implanted at depth in the cover sediments near the top of limestone. An array of deep electrodes is installed with direct push technology in the karst cover. When combined with a surface array in which each surface electrode is underlain by a deep electrode, the array geometry is similar to a borehole array turned on its side. This method, called the Multi-Electrode Resistivity Implant Technique (MERIT), offers the promise of significantly improved resolution of epikarst and cover collapse development zones in the overlying sediment, the limestone or at the sediment-bedrock interface in heterogeneous karst environments. With a non-traditional array design, the question of optimal array geometries arises. Optimizing array geometries is complicated by the fact that many plausible 4-electrode readings will produce negative apparent resistivity values, even in homogeneous terrain. Negative apparent resistivities cannot be used in inversions based on the logarithm of the apparent resistivity. New algorithms for seeking optimal array geometries have been developed by modifying the 'Compare R' method of Wilkinson and Loke. The optimized arrays show significantly improved resolution over basic arrays adapted from traditional 2D surface geometries. Several MERIT case study surveys have been conducted in covered karst in west-central Florida, with

  9. Groundwater recharge assessment at local and episodic scale in a soil mantled perched karst aquifer in southern Italy

    Science.gov (United States)

    Allocca, V.; De Vita, P.; Manna, F.; Nimmo, John R.

    2015-01-01

    Groundwater recharge assessment of karst aquifers, at various spatial and temporal scales, is a major scientific topic of current importance, since these aquifers play an essential role for both socio-economic development and fluvial ecosystems.

  10. Analysis of TCE Fate and Transport in Karst Groundwater Systems Using Statistical Mixed Models

    Science.gov (United States)

    Anaya, A. A.; Padilla, I. Y.

    2012-12-01

    Karst groundwater systems are highly productive and provide an important fresh water resource for human development and ecological integrity. Their high productivity is often associated with conduit flow and high matrix permeability. The same characteristics that make these aquifers productive also make them highly vulnerable to contamination and a likely for contaminant exposure. Of particular interest are trichloroethylene, (TCE) and Di-(2-Ethylhexyl) phthalate (DEHP). These chemicals have been identified as potential precursors of pre-term birth, a leading cause of neonatal complications with a significant health and societal cost. Both of these contaminants have been found in the karst groundwater formations in this area of the island. The general objectives of this work are to: (1) develop fundamental knowledge and determine the processes controlling the release, mobility, persistence, and possible pathways of contaminants in karst groundwater systems, and (2) characterize transport processes in conduit and diffusion-dominated flow under base flow and storm flow conditions. The work presented herein focuses on the use of geo-hydro statistical tools to characterize flow and transport processes under different flow regimes, and their application in the analysis of fate and transport of TCE. Multidimensional, laboratory-scale Geo-Hydrobed models (GHM) were used for this purpose. The models consist of stainless-steel tanks containing karstified limestone blocks collected from the karst aquifer formation of northern Puerto Rico. The models integrates a network of sampling wells to monitor flow, pressure, and solute concentrations temporally and spatially. Experimental work entails injecting dissolved CaCl2 tracers and TCE in the upstream boundary of the GHM while monitoring TCE and tracer concentrations spatially and temporally in the limestone under different groundwater flow regimes. Analysis of the temporal and spatial concentration distributions of solutes

  11. Lignin distribution in waterlogged archaeological Picea abies (L.) Karst degraded by erosion bacteria

    DEFF Research Database (Denmark)

    Pedersen, Nanna Bjerregaard; Schmitt, Uwe Schmitt; Koch, Gerald

    2014-01-01

    The lignin distribution in poles of waterlogged archaeological Picea abies (L.) Karst, which was decayed by erosion bacteria (EB) under anoxic conditions for approximately 400 years, was topochemically identified by transmission electron microscopy (TEM) and high resolution UV-microspectrophotome......The lignin distribution in poles of waterlogged archaeological Picea abies (L.) Karst, which was decayed by erosion bacteria (EB) under anoxic conditions for approximately 400 years, was topochemically identified by transmission electron microscopy (TEM) and high resolution UV...

  12. Characterisation of the heterogeneity of karst using electrical geophysics - applications in SW China

    Science.gov (United States)

    Binley, A. M.; Cheng, Q.; Tao, M.; Chen, X.

    2017-12-01

    The southwest China karst region is one of the largest globally continuous karst areas. The great (structural, hydrological and geochemical) complexity of karstic environments and their rapidly evolving nature make them extremely vulnerable to natural and anthropogenic processes/activities. Characterising the location and properties of structures within the karst critical zone, and understanding how the landform is evolving is essential for the mitigation and adaption to locally- and globally-driven changes. Because of the specific nature of karst geology and geomorphology in the humid tropics and subtropics, spatial heterogeneity is high, evidenced by specific landforms features. Such heterogeneity leads to a high dynamic variability of hydrological processes in space and time, along with a complex exchange of surface water and groundwater. Investigating karst hydrogeological features is extremely challenging because of the three-dimensional nature of the system. Observations from boreholes can vary significantly over several metres, making conventional aquifer investigative methods limited. Geophysical methods have emerged as potentially powerful tools for hydrogeological investigations. Geophysical surveys can help to obtain more insight into the complex conduit networks and depth of weathering, both of which can provide quantitative information about the hydrological and hydrochemical dynamics of the system, in addition to providing a better understanding of how critical zone structures have been established and how the landscape is evolving. We present here results from recent geophysical field campaigns in SW China. We illustrate the effectiveness of electrical methods for mapping soil infil in epikarst and report results from field-based investigations along hillslope and valley transects. Our results reveal distinct zones of relatively high electrical conductivity to depths of tens of metres, which we attribute to localised increased fracture density. We

  13. Using underground mine Karst water to solve water supply problem in underground mine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W. [Wanbei Mining Administration (China). Liuqiao No. 2 Mine

    1995-05-01

    There is a very rich karst water resource under the Liuqiao No. 2 underground mine. Under normal mining conditions the drainage is 546 m{sup 3}/h while the maximum drainage is up to 819 m{sup 3}/h. If water inrush occurred from a broken zone of a fault or a sinkhole of the karst, the flow could be up to 3269 m{sup 3}/h. The karst water is of good quality and high in pressure. The water head pressure at -400 m level is about 3.5 MPa. To save mine construction cost, it was decided that the water supply for coal production equipment, mining operation and mine fire control was to be changed from the surface to the underground by drilling a water well to tap the karst water resource. A water well with a depth of 63.3 m was drilled in the -400 m transportation roadway. The diameter of the well is 127 mm and it has a casing pipe with a diameter of 108 mm which is connected to the water supply pipeline. The pressure of the water supply is measured at 23.5 MPa and the water flow rate is 252 m{sup 3}/h. The establishment of the water supply system has achieved great cost saving for Liuqiao No. 2 Mine. 2 figs.

  14. Numerical Study of Groundwater Flow and Salinity Distribution Cycling Controlled by Seawater/Freshwater Interaction in Karst Aquifer Using SEAWAT

    Science.gov (United States)

    Xu, Z.; Hu, B.

    2017-12-01

    The interest to predict seawater intrusion and salinity distribution in Woodville Karst Plain (WKP) has increased due to the huge challenge on quality of drinkable water and serious environmental problems. Seawater intrudes into the conduit system from submarine karst caves at Spring Creek Spring due to density difference and sea level rising, nowadays the low salinity has been detected at Wakulla Spring which is 18 km from coastal line. The groundwater discharge at two major springs and salinity distribution in this area is controlled by the seawater/freshwater interaction under different rainfall conditions: during low rainfall periods, seawater flow into the submarine spring through karst windows, then the salinity rising at the submarine spring leads to seawater further intrudes into conduit system; during high rainfall periods, seawater is pushed out by fresh water discharge at submarine spring. The previous numerical studies of WKP mainly focused on the density independent transport modeling and seawater/freshwater discharge at major karst springs, in this study, a SEAWAT model has been developed to fully investigate the salinity distribution in the WKP under repeating phases of low rainfall and high rainfall periods, the conduit system was simulated as porous media with high conductivity and porosity. The precipitation, salinity and discharge at springs were used to calibrate the model. The results showed that the salinity distribution in porous media and conduit system is controlled by the rainfall change, in general, the salinity distribution inland under low rainfall conditions is much higher and wider than the high rainfall conditions. The results propose a prediction on the environmental problem caused by seawater intrusion in karst coastal aquifer, in addition, provide a visual and scientific basis for future groundwater remediation.

  15. Community diversity, structure and carbon footprint of nematode food web following reforestation on degraded Karst soil.

    Science.gov (United States)

    Hu, Ning; Li, Hui; Tang, Zheng; Li, Zhongfang; Tian, Jing; Lou, Yilai; Li, Jianwei; Li, Guichun; Hu, Xiaomin

    2016-06-17

    We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H'), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria (F/B) were increased, and nematode channel ratio (NCR) were decreased; carbon footprints of all nematode trophic groups, and biomass of bacteria and fungi were increased. Our results indicate that the Karst aboveground vegetation restoration was accompanied with belowground nematode food web development: increasing community complexity, function and fungal dominance in decomposition pathway, and the driving forces included the bottom-up effect (resource control), connectedness of functional groups, as well as soil environments.

  16. Estimation of underground river water availability based on rainfall in the Maros karst region, South Sulawesi

    Science.gov (United States)

    Arsyad, Muhammad; Ihsan, Nasrul; Tiwow, Vistarani Arini

    2016-02-01

    Maros karst region, covering an area of 43.750 hectares, has water resources that determine the life around it. Water resources in Maros karst are in the rock layers or river underground in the cave. The data used in this study are primary and secondary data. Primary data includes characteristics of the medium. Secondary data is rainfall data from BMKG, water discharge data from the PSDA, South Sulawesi province in 1990-2010, and the other characteristics data Maros karst, namely cave, flora and fauna of the Bantimurung Bulusaraung National Park. Data analysis was conducted using laboratory test for medium characteristics Maros karst, rainfall and water discharge were analyzed using Minitab Program 1.5 to determine their profile. The average rainfall above 200 mm per year occurs in the range of 1999 to 2005. The availability of the water discharge at over 50 m3/s was happened in 1993 and 1995. Prediction was done by modeling Autoregressive Integrated Moving Average (ARIMA), with the rainfall data shows that the average precipitation for four years (2011-2014) will sharply fluctuate. The prediction of water discharge in Maros karst region was done for the period from January to August in 2011, including the type of 0. In 2012, the addition of the water discharge started up in early 2014.

  17. Monthly sediment discharge changes and estimates in a typical karst catchment of southwest China

    Science.gov (United States)

    Li, Zhenwei; Xu, Xianli; Xu, Chaohao; Liu, Meixian; Wang, Kelin; Yi, Ruzhou

    2017-12-01

    As one of the largest karst regions in the world, southwest China is experiencing severe soil erosion due to its special geological conditions, inappropriate land use, and lower soil loss tolerance. Knowledge and accurate estimations of changes in sediment discharge rates is important for finding potential measures to effectively control sediment delivery. This study investigated temporal variation in monthly sediment discharge (SD), and developed sediment rating curves and state-space model to estimate SD. Monthly water discharge, SD, precipitation, potential evapotranspiration, and normalized differential vegetation index during 2003-2015 collected from a typical karst catchment of Yujiang River were analyzed in present study. A Mann-Kendal test and Morlet wavelet analysis were employed to detect the changes in SD. Results indicated that a decreasing trend was observed in sediment discharge at monthly and annual scale. The water and sediment discharge both had a significant 1-year period, implying that water discharge has substantial influence on SD. The best state-space model using water discharge was a simple but effective model, accounting for 99% of the variation in SD. The sediment rating curves, however, represented only 78% of the variation in SD. This study provides an insight into the possibility of accurate estimation of SD only using water discharge with state-space model approach. State-space model is recommended as an effective approach for quantifying the temporal relationships between SD and its driving factors in karst regions of southwest China.

  18. Assessment of key transport parameters in a karst system under different dynamic conditions based on tracer experiments: the Jeita karst system, Lebanon

    Science.gov (United States)

    Doummar, Joanna; Margane, Armin; Geyer, Tobias; Sauter, Martin

    2018-03-01

    Artificial tracer experiments were conducted in the mature karst system of Jeita (Lebanon) under various flow conditions using surface and subsurface tracer injection points, to determine the variation of transport parameters (attenuation of peak concentration, velocity, transit times, dispersivity, and proportion of immobile and mobile regions) along fast and slow flow pathways. Tracer breakthrough curves (TBCs) observed at the karst spring were interpreted using a two-region nonequilibrium approach (2RNEM) to account for the skewness in the TBCs' long tailings. The conduit test results revealed a discharge threshold in the system dynamics, beyond which the transport parameters vary significantly. The polynomial relationship between transport velocity and discharge can be related to the variation of the conduit's cross-sectional area. Longitudinal dispersivity in the conduit system is not a constant value (α = 7-10 m) and decreases linearly with increasing flow rate because of dilution effects. Additionally, the proportion of immobile regions (arising from conduit irregularities) increases with decreasing water level in the conduit system. From tracer tests with injection at the surface, longitudinal dispersivity values are found to be large (8-27 m). The tailing observed in some TBCs is generated in the unsaturated zone before the tracer actually arrives at the major subsurface conduit draining the system. This work allows the estimation and prediction of the key transport parameters in karst aquifers. It shows that these parameters vary with time and flow dynamics, and they reflect the geometry of the flow pathway and the origin of infiltrating (potentially contaminated) recharge.

  19. Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks

    Directory of Open Access Journals (Sweden)

    Z. Xu

    2018-01-01

    Full Text Available Long-distance seawater intrusion has been widely observed through the subsurface conduit system in coastal karst aquifers as a source of groundwater contaminant. In this study, seawater intrusion in a dual-permeability karst aquifer with conduit networks is studied by the two-dimensional density-dependent flow and transport SEAWAT model. Local and global sensitivity analyses are used to evaluate the impacts of boundary conditions and hydrological characteristics on modeling seawater intrusion in a karst aquifer, including hydraulic conductivity, effective porosity, specific storage, and dispersivity of the conduit network and of the porous medium. The local sensitivity analysis evaluates the parameters' sensitivities for modeling seawater intrusion, specifically in the Woodville Karst Plain (WKP. A more comprehensive interpretation of parameter sensitivities, including the nonlinear relationship between simulations and parameters, and/or parameter interactions, is addressed in the global sensitivity analysis. The conduit parameters and boundary conditions are important to the simulations in the porous medium because of the dynamical exchanges between the two systems. The sensitivity study indicates that salinity and head simulations in the karst features, such as the conduit system and submarine springs, are critical for understanding seawater intrusion in a coastal karst aquifer. The evaluation of hydraulic conductivity sensitivity in the continuum SEAWAT model may be biased since the conduit flow velocity is not accurately calculated by Darcy's equation as a function of head difference and hydraulic conductivity. In addition, dispersivity is no longer an important parameter in an advection-dominated karst aquifer with a conduit system, compared to the sensitivity results in a porous medium aquifer. In the end, the extents of seawater intrusion are quantitatively evaluated and measured under different scenarios with the variabilities of

  20. Impact of Diagenesis on Biosignature Preservation Potential in Playa Lake Evaporites of the Verde Formation, Arizona: Implications for Mars Exploration

    Science.gov (United States)

    Shkolyar, S.; Farmer, J. D.

    2016-05-01

    We studied evaporite subfacies in the Verde Fmn., AZ. We identified diagenetic pathways and assessed how diagenesis affected biosignature preservation potential (BPP) in each. Results revealed eight pathways, each with diverse impacts on BPP.

  1. Evaluation of Karst Soil Erosion and Nutrient Loss Based on RUSLE Model in Guizhou Province

    Science.gov (United States)

    Zeng, Cheng; Li, Yangbing; Bai, Xiaoyong; Luo, Guangjie

    2018-01-01

    Based on GIS technology and RUSLE model, the spatial variation characteristics of soil erosion were analyzed in karst areas, and the relationship between soil erosion and soil nutrient loss was discussed. The results showed that the soil differences in spatial variation between nutrient losses. The results illustrate the total soil erosion in is 10316.31 × 104t • a-1, accounting for 84.95% of the total land area in Guizhou Province. The spatial distribution of soil erosion showing the characteristics of the southeast to the northwest strip. The annual average soil erosion modulu is 691.94 t • km-2 • a-1, of which karst is 720.28t • km-2 • a-1 and non-karst is 689.53 t • km-2 • a-1. The total nutrient losses such as soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) were 596.72 × 104t • a-1 due to soil erosion, and SOC, TN and TP and TK were 38.13, 1.61, 0.41 and 14.70t • km-2 • a-1, respectively. The average amount of loss and total loss are the largest in non-karst, and four kinds of nutrient is the smallest in karst gorge. The spatial variation of soil erosion in the study area is the process of increasing the erosion area with the increase of the erosion rate, and the difference of the spatial distribution of soil erosion determines the spatial distribution of soil nutrient loss.

  2. Characterizing pharmaceutical, personal care product, and hormone contamination in a karst aquifer of southwestern Illinois, USA, using water quality and stream flow parameters.

    Science.gov (United States)

    Dodgen, L K; Kelly, W R; Panno, S V; Taylor, S J; Armstrong, D L; Wiles, K N; Zhang, Y; Zheng, W

    2017-02-01

    Karst aquifers are drinking water sources for 25% of the global population. However, the unique geology of karst areas facilitates rapid transfer of surficial chemicals to groundwater, potentially contaminating drinking water. Contamination of karst aquifers by nitrate, chloride, and bacteria have been previously observed, but little knowledge is available on the presence of contaminants of emerging concern (CECs), such as pharmaceuticals. Over a 17-month period, 58 water samples were collected from 13 sites in the Salem Plateau, a karst region in southwestern Illinois, United States. Water was analyzed for 12 pharmaceutical and personal care products (PPCPs), 7 natural and synthetic hormones, and 49 typical water quality parameters (e.g., nutrients and bacteria). Hormones were detected in only 23% of samples, with concentrations of 2.2-9.1ng/L. In contrast, PPCPs were quantified in 89% of groundwater samples. The two most commonly detected PPCPs were the antimicrobial triclocarban, in 81% of samples, and the cardiovascular drug gemfibrozil, in 57%. Analytical results were combined with data of local stream flow, weather, and land use to 1) characterize the extent of aquifer contamination by CECs, 2) cluster sites with similar PPCP contamination profiles, and 3) develop models to describe PPCP contamination. Median detection in karst groundwater was 3 PPCPs at a summed concentration of 4.6ng/L. Sites clustered into 3 subsets with unique contamination models. PPCP contamination in Cluster I sites was related to stream height, manganese, boron, and heterotrophic bacteria. Cluster II sites were characterized by groundwater temperature, specific conductivity, sodium, and calcium. Cluster III sites were characterized by dissolved oxygen and barium. Across all sites, no single or small set of water quality factors was significantly predictive of PPCP contamination, although gemfibrozil concentrations were strongly related to the sum of PPCPs in karst groundwater

  3. Spatial heterogeneities and variability of karst hydro-system : insights from geophysics

    Science.gov (United States)

    Champollion, C.; Fores, B.; Lesparre, N.; Frederic, N.

    2017-12-01

    Heterogeneous systems such as karsts or fractured hydro-systems are challenging for both scientist and groundwater resources management. Karsts heterogeneities prevent the comparison and moreover the combination of data representative of different scales: borehole water level can generally not be used directly to interpret spring flow dynamic for example. The spatial heterogeneity has also an impact on the temporal variability of groundwater transfer and storage. Karst hydro-systems have characteristic non linear relation between precipitation amount and discharge at the outlets with threshold effects and a large variability of groundwater transit times In the presentation, geophysical field experiments conducted in karst hydro-system in the south of France are used to investigate groundwater transfer and storage variability at a scale of a few hundred meters. We focus on the added value of both geophysical time-lapse gravity experiments and 2D ERT imaging of the subsurface heterogeneities. Both gravity and ERT results can only be interpreted with large ambiguity or some strong a priori: the relation between resistivity and water content is not unique; almost no information about the processes can be inferred from the groundwater stock variations. The present study demonstrate how the ERT and gravity field experiments can be interpreted together in a coherent scheme with less ambiguity. First the geological and hydro-meteorological context is presented. Then the ERT field experiment including the processing and the results are detailed in the section about geophysical imaging of the heterogeneities. The gravity double difference (S2D) time-lapse experiment is described in the section about geophysical monitoring of the temporal variability. The following discussion demonstrate the impact of both experiments on the interpretation in terms of processes and heterogeneities.

  4. River Intrusion in Karst Springs in Eogenetic Aquifers: Implications for Speleogenesis

    Science.gov (United States)

    Martin, J. B.; Gulley, J.; Screaton, E. J.

    2008-12-01

    Conceptual models of speleogenesis generally assume uni-directional transport in integrated conduit systems from discrete recharge points to discharge at karst springs. Estavelles, however, are karst springs that function intermittently as discrete recharge points when river stage rises more rapidly than local aquifer heads. As river water chemistry changes between baseflow and floods, estavelles should influence mass transport through (e.g. organic carbon, nutrients, and oxygen) and speleogenesis within karst systems. Estavelles are common in our study area in north-central Florida, particularly along the lower reaches of the Santa Fe River, where it flows across the unconfined karstic Floridan aquifer. River stage in this unconfined region can rise much faster than aquifer heads when large amounts of rain fall on the confined regions in its upper reaches. Backflooding into the estavelles during elevated river stage drives river water into the ground, causing some springs to reverse and other springs to recirculate large volumes of river water. Floodwaters originating in the confined region are highly undersaturated with respect to calcite, and thus river water transitions from slightly supersaturated to highly undersaturated with respect to calcite during flood events. As a result, conduits connected to estavelles are continuously enlarged as springs reverse or recirculate calcite-undersaturated river water. It has been suggested that currently flooded caves (i.e. karst conduits) associated with springs in Florida formed entirely underwater because speleothems, which are prevalent in flooded caves in the Yucatan and Bahamas, have not been observed by cave divers. Results of this study indicate that the absence of speleothems does not necessarily provide evidence of a continuous phreatic history for underwater caves. Instead speleothems that formed in caves while dry could have been dissolved by backflooding of estavelles with undersaturated water

  5. Land use and human impact in the Dinaric karst.

    Directory of Open Access Journals (Sweden)

    Gams Ivan

    1999-01-01

    Full Text Available The artice presents Dinaric karst, human impacts in the area, and its long history of deforestation, transformation into stony semi-desert, and a century long reforestation, where plans to restore the primary thick soil were just hoping against hope.

  6. Adaptations of indigenous bacteria to fuel contamination in karst aquifers in south-central Kentucky

    Science.gov (United States)

    Byl, Thomas D.; Metge, David W.; Agymang, Daniel T.; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

    2014-01-01

    The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The

  7. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    Energy Technology Data Exchange (ETDEWEB)

    Beauheim, R.L. [Sandia National Labs., Albuquerque, NM (United States); Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A. [INTERA, Inc., Austin, TX (United States)

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations.

  8. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    International Nuclear Information System (INIS)

    Beauheim, R.L.; Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A.

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations

  9. Stable sulfur and oxygen isotopes as geochemical tracers of sulfate in karst waters

    Science.gov (United States)

    Sun, Jing; Kobayashi, Tatsuaki; Strosnider, William H. J.; Wu, Pan

    2017-08-01

    Karst water resources, which are extremely sensitive to mining activities, are critical for the support of human societies and ecological systems in many regions worldwide. In order to determine the sources and fate of dissolved sulfate in low-pH karst waters, hydrochemical variations of karst waters with and without acid mine drainage (AMD) impacts were investigated along with stable isotope dynamics. As expected, hydrochemical characteristics and isotopic compositions of the AMD and AMD-downstream water (ADW) were dramatically different from that of the non-AMD-impacted water (NAW). The sources of sulfur isotopes in sulfate were predominantly pyrite oxidation for the AMD and ADW, and atmospheric deposition for the NAW. Based on the general isotope-balance model, the relative proportions of sulfate oxygen derived from water and air were calculated. The mean proportion of sulfate oxygen derived from water in ADW was roughly double that of AMD. This suggests that the sulfate associated with AMD is predominantly influenced by aerobic pyrite oxidation, while that of ADW is likely affected by the dissolution of pyrite under anaerobic conditions in reservoir sediment. This observation was coincident with the noted variations of hydrochemical characteristics and was supported by principal component analysis. These results provide a better understanding of how stable isotopes of sulfate and water can be used to track mining contamination in karst aquifers, which could benefit remediation planning for these distinctive systems.

  10. Digital engineering aspects of Karst map: a GIS version of Davies, W.E., Simpson, J.H., Ohlmacher, G.C., Kirk, W.S., and Newton, E.G., 1984, Engineering aspects of Karst: U.S. Geological Survey, National Atlas of the United States of America, Scale 1:7,500,000

    Science.gov (United States)

    Tobin, Bret D.; Weary, David J.

    2004-01-01

    These data are digital facsimiles of the original 1984 Engineering Aspects of Karst map by Davies and others. This data set was converted from a printed map to a digital GIS coverage to provide users with a citable national scale karst data set to use for graphic and demonstration purposes until new, improved data are developed. These data may be used freely with proper citation. Because it has been converted to GIS format, these data can be easily projected, displayed and queried for multiple uses in GIS. The karst polygons of the original map were scanned from the stable base negatives of the original, vectorized, edited and then attributed with unit descriptions. All of these processes potentially introduce small errors and distortions to the geography. The original map was produced at a scale of 1:7,500,000; this coverage is not as accurate, and should be used for broad-scale purposes only. It is not intended for any site-specific studies.

  11. Do Karst Rivers “deserve” their own biotic index? A ten years study on macrozoobenthos in Croatia

    Directory of Open Access Journals (Sweden)

    Rađa Biljana

    2010-07-01

    Full Text Available In this study we present the results of a ten year survey of the aquatic macroinvertebrate fauna along four karst rivers: Jadro, Žrnovnica, Grab and Ruda, all of them situated in the Middle Dalmatia region of Croatia, in an attempt to construct the Iliric Biotic Index, which will be more applicable for the water quality analysis than the most frequently applied biotic index in Croatia, the Italian Modification of Extended Biotic Index. The rivers geologically belong to the Dinaric karst, unique geological phenomena in Europe. Benthic macroinvertebrates were collected along each river at 15 sites by standard methods of sampling along with several physicochemical parameters, including: temperature, dissolved oxygen, carbon dioxide, alkalinity, hardness and pH. Univariate and multivariate techniques revealed differences in the macroinvertebrate community structure as well as in physicochemical parameters between the Karst rivers and continental rivers. Based on those differences, the Iliric Biotic Index was proposed as the standard of karst river water quality in Croatia in accordance with the EU Water Framework Directive. Differences between the Iliric Biotic Index and the most commonly used biotic indices in the European Community and the USA (The Biological Monitoring Working Party (B.M.W.P. scores, i.e. Extended Biotic Index, Indice Biotique, Family Biotic Index suggest that karst rivers need a new biotic index.

  12. Assessment of subsidence in karst terranes at selected areas in East Tennessee and comparison with a candidate site at Oak Ridge, Tennessee: Phase 2

    International Nuclear Information System (INIS)

    Newton, J.G.; Tanner, J.M.

    1987-09-01

    Work in the respective areas included assessment of conditions related to sinkhole development. Information collected and assessed involved geology, hydrogeology, land use, lineaments and linear trends, identification of karst features and zones, and inventory of historical sinkhole development and type. Karstification of the candidate, Rhea County, and Morristown study areas, in comparison to other karst areas in Tennessee, can be classified informally as youthful, submature, and mature, respectively. Historical sinkhole development in the more karstified areas is attributed to the greater degree of structural deformation by faulting and fracturing, subsequent solutioning of bedrock, thinness of residuum, and degree of development by man. Sinkhole triggering mechanisms identified are progressive solution of bedrock, water-level fluctuations, piping, and loading. 68 refs., 18 figs., 11 tabs

  13. Water exchange and pressure transfer between conduits and matrix and their influence on hydrodynamics of two karst aquifers with sinking streams

    Science.gov (United States)

    Bailly-Comte, Vincent; Martin, Jonathan B.; Jourde, Hervé; Screaton, Elizabeth J.; Pistre, Séverin; Langston, Abigail

    2010-05-01

    SummaryKarst aquifers are heterogeneous media where conduits usually drain water from lower permeability volumes (matrix and fractures). For more than a century, various approaches have used flood recession curves, which integrate all hydrodynamic processes in a karst aquifer, to infer physical properties of the movement and storage of groundwater. These investigations typically only consider flow to the conduits and thus have lacked quantitative observations of how pressure transfer and water exchange between matrix and conduit during flooding could influence recession curves. We present analyses of simultaneous discharge and water level time series of two distinctly different karst systems, one with low porosity and permeability matrix rocks in southern France, and one with high porosity and permeability matrix rocks in north-central Florida (USA). We apply simple mathematical models of flood recession using time series representations of recharge, storage, and discharge processes in the karst aquifer. We show that karst spring hydrographs can be interpreted according to pressure transfer between two distinct components of the aquifer, conduit and matrix porosity, which induce two distinct responses at the spring. Water exchange between conduits and matrix porosity successively control the flow regime at the spring. This exchange is governed by hydraulic head differences between conduits and matrix, head gradients within conduits, and the contrast of permeability between conduits and matrix. These observations have consequences for physical interpretations of recession curves and modeling of karst spring flows, particularly for the relative magnitudes of base flow and quick flow from karst springs. Finally, these results suggest that similar analyses of recession curves can be applied to karst aquifers with distinct physical characteristics utilizing well and spring hydrograph data, but information must be known about the hydrodynamics and physical properties of

  14. Karst water control and management in the Hanxing mining area of North China

    Energy Technology Data Exchange (ETDEWEB)

    Wanfang, Z. [P.E. LaMoreaux and Associates, Inc., Oak Ridge, TN (United States)

    1997-04-01

    The Hanxing mining area of North China includes three coalfields: Fengfeng, Handan and Xingtai. Six or seven coal seams can be commercially mined in Permo-Carboniferous strata, among which the lower three, accounting for 37% of the total reserves, are threatened with karst water from the underlain Ordovician limestone. Hundreds of water inrush accidents have occurred and over 30 mines have been flooded, resulting in heavy economic losses and casualties. In order to avoid water inrushes and keep the mines safely operational, dewatering in the karst aquifer was considered an essential measure. Unfortunately, this practice has caused serious environmental problems such as surface subsidence (sinkhole), dry spring, and water supply shortage. On the basis of a series of investigations and tests in the last 20 years, an alternative method, mining with water pressure, has been proposed and is the main focus of this paper. By using this method, the karst water in the limestone can be preserved to some extent and the coals can be mined in a relatively safe way. (orig.)

  15. Caffeine as an indicator for the quantification of untreated wastewater in karst systems.

    Science.gov (United States)

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2012-02-01

    Contamination from untreated wastewater leakage and related bacterial contamination poses a threat to drinking water quality. However, a quantification of the magnitude of leakage is difficult. The objective of this work is to provide a highly sensitive methodology for the estimation of the mass of untreated wastewater entering karst aquifers with rapid recharge. For this purpose a balance approach is adapted. It is based on the mass flow of caffeine in spring water, the load of caffeine in untreated wastewater and the daily water consumption per person in a spring catchment area. Caffeine is a source-specific indicator for wastewater, consumed and discharged in quantities allowing detection in a karst spring. The methodology was applied to estimate the amount of leaking and infiltrating wastewater to a well investigated karst aquifer on a daily basis. The calculated mean volume of untreated wastewater entering the aquifer was found to be 2.2 ± 0.5 m(3) d(-1) (undiluted wastewater). It corresponds to approximately 0.4% of the total amount of wastewater within the spring catchment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Environmental hydrochemical and stabile isotope methods used to characterise the relation between karst water and surface water

    Directory of Open Access Journals (Sweden)

    Romeo Eftimi

    2017-03-01

    Full Text Available Karst aquifers are characterized by high heterogeneity of groundwater flow. The classical study methods such as boreholes, pumping tests, and point observations give important data but cannot be extended to the entire aquifer. However the environmental hydrochemical and stabile isotope methods could give important information about large scale aquifer characterization. Some study examples from Albania, shown in this paper, demonstrate the successful application of the isotope methods, which are more powerful if applied in combination with hydrochemical ones, for the identification of the karst water recharge sources. Among the isotope methods the altitude effect seems to be more indicative for the solution of the problem concerned. For characterising the lithology of karst rocks and the physical aspects of karst aquifers (type of groundwater flow the combined use of some hydrochemical parameters like the water conductivity, total hardness, ionic ratios rCa/ rMg, rSO4/r/mg, CO2 pressure and the indexes of calcite and (Sic and of dolomite saturation (Sid, result very useful.

  17. Chemical erosion and hydrologic budget for the Susure karst plateau

    Directory of Open Access Journals (Sweden)

    Nikić Zoran

    2010-01-01

    Full Text Available The karst plateau of Susure, about 4.5 km2 in surface area, is situated on the Jadovnik eastern offset, western Serbia. The plateau is a morphologic unit higher 15 m to 30 m than the surrounding terrain. The unit consists of crushed and karstified Middle Triassic limestones. Numerous hydrogeological and geomorphologic features of the plateau are attractive for visitors in this economically underdeveloped country. Rocks building up the surrounding terrain are largely peridotites. Surface streams flow neither into nor off the plateau. Atmospheric precipitations discharge to evapotanspiration and filtration underground. More than eighteen constant springs at the limestone/peridotite tectonic contact drain fracture aquifers on the karst plateau border. Measured precipitations and springflows were the input and output data for accounting water budget of an aquifer of Middle Triassic limestones in the Susure plateau.

  18. Interrelations between the surface waters of Danube, karst waters and thermal springs of Bad Deutsch Altenburg

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, P [Bundesversuchs- und Forschungsanstalt Arsenal, Vienna (Austria)

    1987-11-15

    Full text: As part of the preliminary works for the hydropower project Hainburg on the Danube, comprehensive geological, geophysical, hydrogeological, hydrological, hydrochemical and radiohydrometrical investigations were carried out. Special attention was paid to the area of Bad Deutsch Altenburg since questions of connections between Danube water, groundwater and the sulphur-medicinal springs of Bad Deutsch Altenburg and karst waters had to be settled. Long term observations and the data from series of analysed water samples led to the following conclusions: (1) The thermal deep groundwater, the autochthonous karst water, the shallow groundwater and the Danube belong to a common system with hydraulic interactions. (2) The discharge of the thermal mineral waters in Bad Deutsch Altenburg is caused by a NW-SE striking fault zone. (3) The thermal mineral waters are overburdened by the karst waters in the area Kirchenberg and Pfaffenberg. At the contact zone mixing occurs. Owing to changing pressure conditions and to the locally different conductivity of the karst aquifer the discharges of mineral waters differ in concentration and temperature. (4) The water level of the thermal mineral waterbody is 1 to 2 m above the water level of the Danube at low flow. This difference is equalized at the Danube water level above 141.5 m a.s.l. Above the mark 142 m a.s.l. a direct influence of the observation wells situated in the Park was observed. (5) Because the Danube has eroded the karst massif (Mesozoic limestones and dolomites, Leitha limestone) down to a depth of about 132-133 m a.s.l. the level of karst water drainage was deeper than today. Currently the area is covered by highly permeable gravels. (6) It is therefore assumed that a considerable amount of thermal water drains directly into the Danube. Recharge and mixing with the shallow groundwater was proved. (7) The considerable discharge implies a catchment which extends beyond the immediate environment. (author)

  19. Determining hydraulic parameters of a karst aquifer using unique ...

    African Journals Online (AJOL)

    Although karst aquifers constitute some of the most important water resources worldwide, generally accepted methods for reliably characterising their hydraulic properties are still elusive. This paper aims at contributing to the discussion by a first-ever attempt to utilise various sets of unique historical data derived from ...

  20. Single event time series analysis in a binary karst catchment evaluated using a groundwater model (Lurbach system, Austria).

    Science.gov (United States)

    Mayaud, C; Wagner, T; Benischke, R; Birk, S

    2014-04-16

    The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the

  1. An Efficient Upscaling Procedure Based on Stokes-Brinkman Model and Discrete Fracture Network Method for Naturally Fractured Carbonate Karst Reservoirs

    KAUST Repository

    Qin, Guan

    2010-01-01

    Naturally-fractured carbonate karst reservoirs are characterized by various-sized solution caves that are connected via fracture networks at multiple scales. These complex geologic features can not be fully resolved in reservoir simulations due to the underlying uncertainty in geologic models and the large computational resource requirement. They also bring in multiple flow physics which adds to the modeling difficulties. It is thus necessary to develop a method to accurately represent the effect of caves, fractures and their interconnectivities in coarse-scale simulation models. In this paper, we present a procedure based on our previously proposed Stokes-Brinkman model (SPE 125593) and the discrete fracture network method for accurate and efficient upscaling of naturally fractured carbonate karst reservoirs.

  2. Hydrological deformation signals in karst systems: new evidence from the European Alps

    Science.gov (United States)

    Serpelloni, E.; Pintori, F.; Gualandi, A.; Scoccimarro, E.; Cavaliere, A.; Anderlini, L.; Belardinelli, M. E.; Todesco, M.

    2017-12-01

    The influence of rainfall on crustal deformation has been described at local scales, using tilt and strain meters, in several tectonic settings. However, the literature on the spatial extent of rainfall-induced deformation is still scarce. We analyzed 10 years of displacement time-series from 150 continuous GPS stations operating across the broad zone of deformation accommodating the N-S Adria-Eurasia convergence and the E-ward escape of the Eastern Alps toward the Pannonian basin. We applied a blind-source-separation algorithm based on a variational Bayesian Independent Component Analysis method to the de-trended time-series, being able to characterize the temporal and spatial features of several deformation signals. The most important ones are a common mode annual signal, with spatially uniform response in the vertical and horizontal components and a time-variable, non-cyclic, signal characterized by a spatially variable response in the horizontal components, with stations moving (up to 8 mm) in the opposite directions, reversing the sense of movement in time. This implies a succession of extensional/compressional strains, with variable amplitudes through time, oriented normal to rock fractures in karst areas. While seasonal displacements in the vertical component (with an average amplitude of 4 mm over the study area) are satisfactorily reproduced by surface hydrological loading, estimated from global assimilation models, the non seasonal signal is associated with groundwater flow in karst systems, and is mainly influencing the horizontal component. The temporal evolution of this deformation signal is correlated with cumulated precipitation values over periods of 200-300 days. This horizontal deformation can be explained by pressure changes associated with variable water levels within vertical fractures in the vadose zones of karst systems, and the water level changes required to open or close these fractures are consistent with the fluctuations of precipitation

  3. [Characteristics of foliar delta13C values of common shrub species in various microhabitats with different karst rocky desertification degrees].

    Science.gov (United States)

    Du, Xue-Lian; Wang, Shi-Jie; Rong, Li

    2011-12-01

    By measuring the foliar delta13C values of 5 common shrub species (Rhamnus davurica, Pyracantha fortuneana, Rubus biflorus, Zanthoxylum planispinum, and Viburnum utile) growing in various microhabitats in Wangjiazhai catchment, a typical karst desertification area in Guizhou Province, this paper studied the spatial heterogeneity of plant water use at niche scale and the response of the heterogeneity to different karst rocky desertification degrees. The foliar delta13C values of the shrub species in the microhabitats followed the order of stony surface > stony gully > stony crevice > soil surface, and those of the majority of the species were more negative in the microhabitat soil surface than in the others. The foliar delta13C values decreased in the sequence of V. utile > R. biflorus > Z. planispinum > P. fortuneana > R. davurica, and the mean foliar delta13C value of the shrubs and that of typical species in various microhabitats all increased with increasing karst rocky desertification degree, differed significantly among different microhabitats. It was suggested that with the increasing degree of karst rocky desertification, the structure and functions of karst habitats were impaired, microhabitats differentiated gradually, and drought degree increased.

  4. Carbon gains by conservation projects overbalance carbon losses by degradation in China's karst ecoregions

    Science.gov (United States)

    Tong, X.; Yue, Y.; Fensholt, R.; Brandt, M.

    2017-12-01

    China's ecological restoration projects are considered as "mega-engineering" activities and the most ambitious afforestation and conservation projects in human history. The highly sensitive and vulnerable karst ecosystem in Southwest China is one of the largest exposed carbonate rock areas (more than 0.54 million km2) in the world. Accelerating desertification has been reported during the last half century, caused by the increasing intensity of human exploitation of natural resources. As a result, vast karst areas (approximately 0.12 million km2) previously covered by vegetation and soil were turned into a rocky landscape. To combat this severe form of land degradation, more than 19 billion USD have been invested in mitigation initiatives since the end of the 1990s. The costs of mega-engineering as a climate change mitigation measure are however only justified if ecosystem properties can be affected at large scales. Here we study the carbon balance of the karst regions of 8 Chinese provinces over four decades, using optical and passive microwave satellite data, supported by statistical data on project implementations. We find that most areas experiencing losses in aboveground biomass carbon are located in areas with a high standing biomass ( 95 Mg C ha-1), whereas areas with a carbon gain are mostly located in regions with a low standing biomass ( 45 Mg C ha-1). However, the overall gains in carbon stocks overbalance the losses, with an average gross loss of -0.8 Pg C and a gross gain of +2.4 Pg C (1980s to 2016), resulting in a net gain of 1.6 Pg C. Areas of carbon gains are widespread and spatially coherent with conservation projects implemented after 2001, whereas areas of carbon losses show that ongoing degradation is still happening in the western parts of the karst regions. We conclude that the impact of conservation projects on the carbon balance of China's karst ecoregions is remarkable, but biomass carbon losses caused by ongoing degradation can not be

  5. Regional-scale analysis of karst underground flow deduced from tracing experiments: examples from carbonate aquifers in Malaga province, southern Spain

    Science.gov (United States)

    Barberá, J. A.; Mudarra, M.; Andreo, B.; De la Torre, B.

    2018-02-01

    Tracer concentration data from field experiments conducted in several carbonate aquifers (Malaga province, southern Spain) were analyzed following a dual approach based on the graphical evaluation method (GEM) and solute transport modeling to decipher flow mechanisms in karst systems at regional scale. The results show that conduit system geometry and flow conditions are the principal factors influencing tracer migration through the examined karst flow routes. Solute transport is mainly controlled by longitudinal advection and dispersion throughout the conduit length, but also by flow partitioning between mobile and immobile fluid phases, while the matrix diffusion process appears to be less relevant. The simulation of tracer breakthrough curves (BTCs) suggests that diffuse and concentrated flow through the unsaturated zone can have equivalent transport properties under extreme recharge, with high flow velocities and efficient mixing due to the high hydraulic gradients generated. Tracer mobilization within the saturated zone under low flow conditions mainly depends on the hydrodynamics (rather than on the karst conduit development), which promote a lower longitudinal advection and retardation in the tracer migration, resulting in a marked tailing effect of BTCs. The analytical advection-dispersion equation better approximates the effective flow velocity and longitudinal dispersion estimations provided by the GEM, while the non-equilibrium transport model achieves a better adjustment of most asymmetric and long-tailed BTCs. The assessment of karst underground flow properties from tracing tests at regional scale can aid design of groundwater management and protection strategies, particularly in large hydrogeological systems (i.e. transboundary carbonate aquifers) and/or in poorly investigated ones.

  6. Hydrologic Conditions that Influence Streamflow Losses in a Karst Region of the Upper Peace River, Polk County, Florida

    Science.gov (United States)

    Metz, P.A.; Lewelling, B.R.

    2009-01-01

    The upper Peace River from Bartow to Fort Meade, Florida, is described as a groundwater recharge area, reflecting a reversal from historical groundwater discharge patterns that existed prior to the 1950s. The upper Peace River channel and floodplain are characterized by extensive karst development, with numerous fractures, crevasses, and sinks that have been eroded in the near-surface and underlying carbonate bedrock. With the reversal in groundwater head gradients, river water is lost to the underlying groundwater system through these karst features. An investigation was conducted to evaluate the hydrologic conditions that influence streamflow losses in the karst region of the upper Peace River. The upper Peace River is located in a basin that has been altered substantially by phosphate mining and increases in groundwater use. These alterations have changed groundwater flow patterns and caused streamflow declines through time. Hydrologic factors that have had the greatest influence on streamflow declines in the upper Peace River include the lowering of the potentiometric surfaces of the intermediate aquifer system and Upper Floridan aquifer beneath the riverbed elevation due to below-average rainfall (droughts), increases in groundwater use, and the presence of numerous karst features in the low-water channel and floodplain that enhance the loss of streamflow. Seepage runs conducted along the upper Peace River, from Bartow to Fort Meade, indicate that the greatest streamflow losses occurred along an approximate 2-mile section of the river beginning about 1 mile south of the Peace River at Bartow gaging station. Along the low-water and floodplain channel of this 2-mile section, there are about 10 prominent karst features that influence streamflow losses. Losses from the individual karst features ranged from 0.22 to 16 cubic feet per second based on measurements made between 2002 and 2007. The largest measured flow loss for all the karst features was about 50 cubic

  7. Invasive vascular plant species of limnocrenic karst springs in Poland

    Science.gov (United States)

    Spałek, Krzysztof

    2015-04-01

    Natural water reservoirs are very valuable floristic sites in Poland. Among them, the most important for preservation of biodiversity of flora are limnocrenic karst springs. The long-term process of human pressure on habitats of this type caused disturbance of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of last two hundred years, led to systematic disappearance of localities of many plant species connected with rare habitats and also to appear numerous invasive plant species. They are: Acorus calamus, Echinocystis lobata, Elodea canadensis, Erechtites hieraciifolia, Impatiens glandulifera, Solidago canadensis, S. gigantea and S. graminifolia. Fielworks were conducted in 2010-2014.

  8. The importance of non-carbonate mineral weathering as a soil formation mechanism within a karst weathering profile in the SPECTRA Critical Zone Observatory, Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    Oliver W.Moore; Heather L.Buss; Sophie M.Green; Man Liu; Zhaoliang Song

    2017-01-01

    Soil degradation,including rocky desertification,of the karst regions in China is severe.Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded.Understanding the balance between soil formation and soil erosion is critical for long-term soil sustainability,yet little is known about the initial soil forming processes on karst terrain.Herein we examine the initial weathering processes of several types of carbonate bedrock containing varying amounts of non-carbonate minerals in the SPECTRA Critical Zone Observatory,Guizhou Province,Southwest China.We compared the weathering mechanisms of the bedrock to the mass transfer of mineral nutrients in a soil profile developed on these rocks and found that soil formation and nutrient contents are strongly dependent upon the weathering of interbedded layers of more silicate-rich bedrock (marls).Atmospheric inputs from dust were also detected.

  9. Quantitative extraction of the bedrock exposure rate based on unmanned aerial vehicle data and Landsat-8 OLI image in a karst environment

    Science.gov (United States)

    Wang, Hongyan; Li, Qiangzi; Du, Xin; Zhao, Longcai

    2017-12-01

    In the karst regions of southwest China, rocky desertification is one of the most serious problems in land degradation. The bedrock exposure rate is an important index to assess the degree of rocky desertification in karst regions. Because of the inherent merits of macro-scale, frequency, efficiency, and synthesis, remote sensing is a promising method to monitor and assess karst rocky desertification on a large scale. However, actual measurement of the bedrock exposure rate is difficult and existing remote-sensing methods cannot directly be exploited to extract the bedrock exposure rate owing to the high complexity and heterogeneity of karst environments. Therefore, using unmanned aerial vehicle (UAV) and Landsat-8 Operational Land Imager (OLI) data for Xingren County, Guizhou Province, quantitative extraction of the bedrock exposure rate based on multi-scale remote-sensing data was developed. Firstly, we used an object-oriented method to carry out accurate classification of UAVimages. From the results of rock extraction, the bedrock exposure rate was calculated at the 30 m grid scale. Parts of the calculated samples were used as training data; other data were used for model validation. Secondly, in each grid the band reflectivity of Landsat-8 OLI data was extracted and a variety of rock and vegetation indexes (e.g., NDVI and SAVI) were calculated. Finally, a network model was established to extract the bedrock exposure rate. The correlation coefficient of the network model was 0.855, that of the validation model was 0.677 and the root mean square error of the validation model was 0.073. This method is valuable for wide-scale estimation of bedrock exposure rate in karst environments. Using the quantitative inversion model, a distribution map of the bedrock exposure rate in Xingren County was obtained.

  10. Simulating groundwater flow in karst aquifers with distributed parameter models—Comparison of porous-equivalent media and hybrid flow approaches

    Science.gov (United States)

    Kuniansky, Eve L.

    2016-09-22

    Understanding karst aquifers, for purposes of their management and protection, poses unique challenges. Karst aquifers are characterized by groundwater flow through conduits (tertiary porosity), and (or) layers with interconnected pores (secondary porosity) and through intergranular porosity (primary or matrix porosity). Since the late 1960s, advances have been made in the development of numerical computer codes and the use of mathematical model applications towards the understanding of dual (primary [matrix] and secondary [fractures and conduits]) porosity groundwater flow processes, as well as characterization and management of karst aquifers. The Floridan aquifer system (FAS) in Florida and parts of Alabama, Georgia, and South Carolina is composed of a thick sequence of predominantly carbonate rocks. Karst features are present over much of its area, especially in Florida where more than 30 first-magnitude springs occur, numerous sinkholes and submerged conduits have been mapped, and numerous circular lakes within sinkhole depressions are present. Different types of mathematical models have been applied for simulation of the FAS. Most of these models are distributed parameter models based on the assumption that, like a sponge, water flows through connected pores within the aquifer system and can be simulated with the same mathematical methods applied to flow through sand and gravel aquifers; these models are usually referred to as porous-equivalent media models. The partial differential equation solved for groundwater flow is the potential flow equation of fluid mechanics, which is used when flow is dominated by potential energy and has been applied for many fluid problems in which kinetic energy terms are dropped from the differential equation solved. In many groundwater model codes (basic MODFLOW), it is assumed that the water has a constant temperature and density and that flow is laminar, such that kinetic energy has minimal impact on flow. Some models have

  11. The Study of Abundance of Soil Minerals on Micro Toposequen of Karst Gunungsewu Pegunungan Selatan

    Directory of Open Access Journals (Sweden)

    Djoko Mulyanto

    2008-05-01

    Full Text Available Landform of Gunungsewu karst topography dominated by positive forms consists of hills and negative forms of dolines. On the micro toposequen of karst, most of dolines dominated by red soils which hue 2.5 YR – 5 YR, whereas on hills by soils which hue 5 YR – 7.5 YR. The aim of research was to study of soil minerals status on karst micro toposequent. Results showed that soil minerals of sand fraction on dolines dominated by quartz, opaque, and iron concretion, whereas on hills dominated by labradorite, and mafic minerals. Clay minerals on doline dominated by kaolinite whereas on hills by halloysite. The high concentration of kaolinite, quartz, opaque and iron concretions of soils on dolines appropriate with degree of soil weathering which in a line with decreasing of soil pH, silt/ clay ratio, and hue of soils on dolines redder than hue of soils on hills. The origin of soil parent material suggested come from volcanic materials.

  12. Diversitas Kelelawar (Chiroptera Penghuni Gua, Studi Gua Ngerong di Kawasan Karst Tuban Jawa Timur

    Directory of Open Access Journals (Sweden)

    Tatag Bagus Putra Prakarsa

    2013-12-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui diversitas kelelawar penghuni gua di gua Ngerong. Penelitian ini merupakan penelitian Nature Snapshop Experiment (NSE. Penelitian ini dilaksanakan pada bulan November - Desember 2011 di gua Ngerong, Desa Rengel, Kecamatan Rengel, Kabupaten Tuban, Jawa Timur. Penangkapan dilakukan dengan metode tangkap langsung. Penangkapan dilakukan dengan menggunakan misnet dan handnet. Kelelawar diidentifikasi berdasarkan pengukuran morfometri dan ciri morfologi mengacu kunci identifikasi Suyanto, 2001 dan Payne et al., 2000. Seluruh data dianalisis secara deskriptif. Di gua Ngerong terdapat 9 spesies dari 4 famili atau 60% dari total spesies kelelawar penghuni gua di kawasan karst Tuban. Enam spesies anggota Subordo Microchiroptera yang merupakan insectivor dan 3 spesies anggota Subordo Megachiroptera yang merupakan frugivor dan nictivor. Keanekaragaman di gua Ngerong tergolong tinggi dengan nilai Simpson's Diversity Index sebesar 0,76. Tingginya diversitas kelelawar penghuni gua Ngerong berbanding lurus dengan panjang lorong gua Ngerong. gua Ngerong merupakan gua terpanjang di kawasan karst Tuban, dengan panjang lorong mencapai 1800m.kata kunci: Kelelawar (Chiroptera, Diversitas, Gua Ngerong, Biospeleologi, Karst

  13. Land use in the tropical karst - the case of Peruaçu, Januària and Jaiba; SE Brazil.

    Directory of Open Access Journals (Sweden)

    Kohler Heinz Charles

    1999-01-01

    Full Text Available The karstic regions of the municipalities of Peruaçu, Januària and Jaiba present a variety of soil uses which are a function of the organization of the karstic relief. This relief system forms a rift, which received fluvial sediments deposition from the Sào Francisco River. The horst of the Peruaçu plateau is developed on limestone rocks of Late Proterozoic age with a high concentration of calcium carbonate. The South American Surface was formed on this and is today occupied by cattle ranching. In the graben, due to easy irrigation from underground karst waters and because of the nearby drainage system of the Sào Francisco River, a mechanized and specialized farming system has developed. The change in the management of cattle breeding and in traditional farming methods has had a substantial impact on the economic structure of the community and also on the karst itself.

  14. A method of mapping sinkhole susceptibility using a geographic information system : a case study for interstates in the karst counties of Virginia.

    Science.gov (United States)

    2015-02-01

    This study proposes the use of a geographic information system (GIS) to create a susceptibility map, pinpointing : regions in the karst counties of Virginia, in particular, along interstates, most susceptible to future sinkhole : development, determi...

  15. Geologic and climatic controls on streamflow generation processes in a complex eogenetic karst basin

    Science.gov (United States)

    Vibhava, F.; Graham, W. D.; Maxwell, R. M.

    2012-12-01

    Streamflow at any given location and time is representative of surface and subsurface contributions from various sources. The ability to fully identify the factors controlling these contributions is key to successfully understanding the transport of contaminants through the system. In this study we developed a fully integrated 3D surface water-groundwater-land surface model, PARFLOW, to evaluate geologic and climatic controls on streamflow generation processes in a complex eogenetic karst basin in North Central Florida. In addition to traditional model evaluation criterion, such as comparing field observations to model simulated streamflow and groundwater elevations, we quantitatively evaluated the model's predictions of surface-groundwater interactions over space and time using a suite of binary end-member mixing models that were developed using observed specific conductivity differences among surface and groundwater sources throughout the domain. Analysis of model predictions showed that geologic heterogeneity exerts a strong control on both streamflow generation processes and land atmospheric fluxes in this watershed. In the upper basin, where the karst aquifer is overlain by a thick confining layer, approximately 92% of streamflow is "young" event flow, produced by near stream rainfall. Throughout the upper basin the confining layer produces a persistent high surficial water table which results in high evapotranspiration, low groundwater recharge and thus negligible "inter-event" streamflow. In the lower basin, where the karst aquifer is unconfined, deeper water tables result in less evapotranspiration. Thus, over 80% of the streamflow is "old" subsurface flow produced by diffuse infiltration through the epikarst throughout the lower basin, and all surface contributions to streamflow originate in the upper confined basin. Climatic variability provides a secondary control on surface-subsurface and land-atmosphere fluxes, producing significant seasonal and

  16. Surface-water and karst groundwater interactions and streamflow-response simulations of the karst-influenced upper Lost River watershed, Orange County, Indiana

    Science.gov (United States)

    Bayless, E. Randall; Cinotto, Peter J.; Ulery, Randy L.; Taylor, Charles J.; McCombs, Gregory K.; Kim, Moon H.; Nelson, Hugh L.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE) and the Indiana Office of Community and Rural Affairs (OCRA), conducted a study of the upper Lost River watershed in Orange County, Indiana, from 2012 to 2013. Streamflow and groundwater data were collected at 10 data-collection sites from at least October 2012 until April 2013, and a preliminary Water Availability Tool for Environmental Resources (WATER)-TOPMODEL based hydrologic model was created to increase understanding of the complex, karstic hydraulic and hydrologic system present in the upper Lost River watershed, Orange County, Ind. Statistical assessment of the optimized hydrologic-model results were promising and returned correlation coefficients for simulated and measured stream discharge of 0.58 and 0.60 and Nash-Sutcliffe efficiency values of 0.56 and 0.39 for USGS streamflow-gaging stations 03373530 (Lost River near Leipsic, Ind.), and 03373560 (Lost River near Prospect, Ind.), respectively. Additional information to refine drainage divides is needed before applying the model to the entire karst region of south-central Indiana. Surface-water and groundwater data were used to tentatively quantify the complex hydrologic processes taking place within the watershed and provide increased understanding for future modeling and management applications. The data indicate that during wet-weather periods and after certain intense storms, the hydraulic capacity of swallow holes and subsurface conduits is overwhelmed with excess water that flows onto the surface in dry-bed relic stream channels and karst paleovalleys. Analysis of discharge data collected at USGS streamflow-gaging station 03373550 (Orangeville Rise, at Orangeville, Ind.), and other ancillary data-collection sites in the watershed, indicate that a bounding condition is likely present, and drainage from the underlying karst conduit system is potentially limited to near 200 cubic feet per second. This

  17. Results of a hydrogeological and hydrogeochemical study of a semi-arid karst aquifer in Tezbent plateau, Tebessa region, northeast of Algeria

    Science.gov (United States)

    Belfar, Dalila; Fehdi, Chemseddine; Baali, Fethi; Salameh, Elias

    2017-06-01

    The Hammamet Plain, situated in the northwest of the Tezbent mountain range, northeast of Algeria, drains carbonate aquifers through some important karst springs. The physical and chemical characteristics of spring and well water samples were studied for 2 years to assess the origin of groundwater and determine the factors driving the geochemical composition. The ionic speciation and mineral dissolution/precipitation was calculated. Water wells, characterizing groundwater circulation at shallow depths, are moderate to high mineralized waters of Na-HCO3 type. In contrast to the shallow environment, the CO2-rich, deeper waters are of the Ca-HCO3-SO4 type and undergo significant changes in the baseline chemistry along flow lines with increasing residence time. The main factors controlling the groundwater composition and its seasonal variations are the geology, because of the presence of carbonate formations, the elevation and the rate of karst development. In both groups, the carbonate chemistry is diagnostic of the effect of karst development. The supersaturation with respect to calcite indicates CO2 degassing, occurring either inside the aquifer in open conduits, or at the outlet in reservoirs. The undersaturation with respect to calcite shows the existence of fast flow and short residence time conditions inside the aquifer. Interaction between groundwater and surrounding host rocks is believed to be the main process responsible for the observed chemical characteristics of groundwater in the study area.

  18. Review: The Yucatán Peninsula karst aquifer, Mexico

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Gondwe, Bibi Ruth Neuman; Charvet, Guillaume

    2011-01-01

    in the vicinity of the North American/Caribbean plate boundary and has been reshaped by a series of tectonic events over its long geologic history. At the end of the Cretaceous period, the Yucatán Peninsula was hit by a large asteroid, which formed the Chicxulub impact crater. The Yucatán Peninsula karst aquifer...

  19. Enhanced nitrogen availability in karst ecosystems by oxalic acid release in the rhizosphere

    Directory of Open Access Journals (Sweden)

    Fujing ePan

    2016-05-01

    Full Text Available In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM and causes nitrogen (N and/or phosphorus (P limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015 where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass C (MBC, and β-1,4-N-acetylglucosaminidase (NAG on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems.

  20. Occurrence of Pepper Mild Mottle Virus (PMMoV) in Groundwater from a Karst Aquifer System in the Yucatan Peninsula, Mexico.

    Science.gov (United States)

    Rosiles-González, Gabriela; Ávila-Torres, Gerardo; Moreno-Valenzuela, Oscar A; Acosta-González, Gilberto; Leal-Bautista, Rosa María; Grimaldo-Hernández, Cinthya D; Brown, Judith K; Chaidez-Quiroz, Cristóbal; Betancourt, Walter Q; Gerba, Charles P; Hernández-Zepeda, Cecilia

    2017-12-01

    The Yucatan Peninsula of Mexico hosts a karst aquifer system that is the only source of freshwater for the area; however, it is vulnerable to human-mediated contamination. Pepper mild mottle virus (PMMoV) is one of the most abundant RNA viruses associated with human feces, making it a viable indicator for tracking fecal pollution in aquatic environments, including groundwater. In this study, groundwater samples collected from a karst aquifer from fresh and brackish water locations were analyzed for fecal indicator bacteria, somatic and male F+ specific coliphages, and PMMoV during the rainy and dry seasons. Total coliform bacteria were detected at all sites, whereas Escherichia coli were found at relatively low levels water type (p > 0.05). Physicochemical and indicator bacteria were not correlated with PMMoV concentrations. The abundance and prevalence of PMMoV in the karst aquifer may reflect its environmental persistence and its potential as a fecal indicator in this karst aquifer system.

  1. Characterizing the interaction of groundwater and surface water in the karst aquifer of Fangshan, Beijing (China)

    Science.gov (United States)

    Chu, Haibo; Wei, Jiahua; Wang, Rong; Xin, Baodong

    2017-03-01

    Correct understanding of groundwater/surface-water (GW-SW) interaction in karst systems is of greatest importance for managing the water resources. A typical karst region, Fangshan in northern China, was selected as a case study. Groundwater levels and hydrochemistry analyses, together with isotope data based on hydrogeological field investigations, were used to assess the GW-SW interaction. Chemistry data reveal that water type and the concentration of cations in the groundwater are consistent with those of the surface water. Stable isotope ratios of all samples are close to the local meteoric water line, and the 3H concentrations of surface water and groundwater samples are close to that of rainfall, so isotopes also confirm that karst groundwater is recharged by rainfall. Cross-correlation analysis reveals that rainfall leads to a rise in groundwater level with a lag time of 2 months and groundwater exploitation leads to a fall within 1 month. Spectral analysis also reveals that groundwater level, groundwater exploitation and rainfall have significantly similar response periods, indicating their possible inter-relationship. Furthermore, a multiple nonlinear regression model indicates that groundwater level can be negatively correlated with groundwater exploitation, and positively correlated with rainfall. The overall results revealed that groundwater level has a close correlation with groundwater exploitation and rainfall, and they are indicative of a close hydraulic connection and interaction between surface water and groundwater in this karst system.

  2. Evolution of a Lowland Karst Landscape; A Mass-Balance Approach

    Science.gov (United States)

    Chamberlin, C.; Heffernan, J. B.; Cohen, M. J.; Quintero, C.; Pain, A.

    2016-12-01

    Karst landscapes are highly soluble, and are vulnerable to biological acid production as a major driving factor in their evolution. Big Cypress National Park (BICY) is a low-lying karst landscape in southern Florida displaying a distinctive morphology of isolated depressions likely influenced by biology. The goal of this study is to constrain timescales of landform development in BICY. This question was addressed through the construction of landscape-scale elemental budgets for both calcium and phosphorus. Precipitation and export fluxes were calculated using available chemistry and hydrology data, and stocks were calculated from a combination of existing data, field measurements, and laboratory chemical analysis. Estimates of expected mass export given no biological acid production and given an equivalent production of 100% of GPP were compared with observed rates. Current standing stocks of phosphorus are dominated by a large soil pool, and contain 500 Gg P. Inputs are largely dominated by precipitation, and 8000 years are necessary to accumulate standing stocks of phosphorus given modern fluxes. Calcium flux is vastly dominated by dissolution of the limestone bedrock, and though some calcium is retained in the soil, most is exported. Using LiDAR generated estimates of volume loss across the landscape and current export rates, an estimated 15,000 years would be necessary to create the modern landscape. Both of these estimates indicate that the BICY landscape is geologically very young. The different behaviors of these elements (calcium is largely exported, while phosphorus is largely retained) lend additional confidence to estimates of denudation rates of the landscape. These estimates can be even closer reconciled if calcium redistribution over the landscape is allowed for. This estimate is compared to the two bounding conditions for biological weathering to indicate a likely level of biological importance to landscape development in this system.

  3. Calcareous nannofossil events in the pre-evaporitic Messinian

    Science.gov (United States)

    Negri, Alessandra; Lozar, Francesca

    2017-04-01

    During the Messinian (7.2 to 5.3 Ma) the Mediterranean area experienced fast and deep climatic and eustatic structural changes. The stratigraphic framework for this interval is relatively well constrained and the beginning of the Messinian salinity crisis dated at 5.97 Ma determine a duration of at least 1.2 Ma for the pre-evaporitic Messinian that is object of this study. Several sites (Faneromeni, Pissouri, Polemi Fanantello borehole, Lemme, Pollenzo, Govone, Moncalvo; Wade and Bown, 2006; Kouwenhoven et al 2006, Morigi et al 2007, Lozar et al 2010, Dela Pierre et al 2011) show similar calcareous nannofossil record behavior, with several Sphenolithus spp. peaks recognised at different quotes in each of the sections. Aim of the present work is to compare the calcareous nannofossil data achieved in the above mentioned sections: interestingly, the occurrence of strongly oligotypic assemblages related to high salinity and unstable environments, appear to correlate precisely among the investigated sites and occur immediately before the onset of the Messinian salinity crisis, then offering the possibility to use them as bioevents for regional correlation. References Dela Pierre, F., Bernardi, E., Cavagna, S., Clari, P., Gennari, R., Irace, A., Lozar, F., Lugli, S., Manzi, V., Natalicchio, M., Roveri, M., Violanti, D., 2011. The record of the Messinian salinity crisis in the Tertiary Piedmont Basin (NW Italy): The Alba section revisited. Palaeogeography, Palaeoclimatology, Palaeoecology 310, 238-255. Kouwenhoven, T.J., Morigi, C., Negri, A., Giunta, S., Krijgsman, W., Rouchy, J.M., 2006 Paleoenvironmental evolution of the eastern Mediterranean during the Messinian: Constraints from integrated microfossil data of the Pissouri Basin (Cyprus). Marine Micropaleontology 60, 17-44. Lozar, F., Violanti, D., Dela Pierre, F., Bernardi, E., Cavagna, S., Clari, P., Irace, A., Martinetto, E., Trenkwalder, S., 2010. Calcareous nannofossils and foraminifers herald the Messinian

  4. Bryophyte communities as biomonitors of environmental factors in the Goujiang karst bauxite, southwestern China.

    Science.gov (United States)

    Wang, Shiqiang; Zhang, Zhaohui; Wang, Zhihui

    2015-12-15

    Bauxite mining on karst results in several ecological and environmental issues including heavy metal pollution, soil erosion and the destruction of vegetation. In turn, these may affect the distribution of plant communities and endanger human health. In general, bryophytes (mosses, liverworts and hornworts) are pioneer plants, lacking roots, vascular systems and well-developed cuticles. Due to their high sensitivity to the environment, they are often used to monitor air and soil pollution. A total of 25 bryophyte taxa from 19 genera and 9 families were recorded on Goujiang karst bauxite near the city of Zunyi in the Guizhou Province of southwestern China. Eleven principal bryophyte communities were identified, most of which consisted of only one species (monospecific assemblage), although the proportion of these single-species communities differed at the six locations. The levels of heavy metals also differed in soil from the six locations: iron, 8748.9-10,023μg/g; zinc, 146.7-240.9μg/g; copper, 24.6-60.4μg/g; and nickel, 35.6-95.1μg/g. A canonical correspondence analysis (CCA) of the bryophyte communities and environmental variables revealed the effect of gradient (slope), altitude and heavy metals in the soil on the distribution of the principal bryophyte communities. More than 36% of bryophyte taxa identified reproduced asexually by gemmae, as gemmiferous bryophyte communities tolerate substrates with high levels of heavy metals more readily than non-gemmiferous communities do. The distribution of heavy metals in the soil is reflected in the distribution of the bryophyte communities. The distribution characteristics of the principal bryophyte communities and of the gemmiferous bryophyte communities are useful in monitoring heavy metal pollution in karst bauxite. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Both temperature fluctuations and East Asian monsoons have driven plant diversification in the karst ecosystems from southern China.

    Science.gov (United States)

    Kong, Hanghui; Condamine, Fabien L; Harris, A J; Chen, Junlin; Pan, Bo; Möller, Michael; Hoang, Van Sam; Kang, Ming

    2017-11-01

    Karst ecosystems in southern China are species-rich and have high levels of endemism, yet little is known regarding the evolutionary processes responsible for the origin and diversification of karst biodiversity. The genus Primulina (Gesneriaceae) comprises ca. 170 species endemic to southern China with high levels of ecological (edaphic) specialization, providing an exceptional model to study the plant diversification in karsts. We used molecular data from nine chloroplast and 11 nuclear regions and macroevolutionary analyses to assess the origin and cause of species diversification due to palaeoenvironmental changes and edaphic specialization in Primulina. We found that speciation was positively associated with changes in past temperatures and East Asian monsoons through the evolutionary history of Primulina. Climatic change around the mid-Miocene triggered an early burst followed by a slowdown of diversification rate towards the present with the climate cooling. We detected different speciation rates among edaphic types, and transitions among soil types were infrequently and did not impact the overall speciation rate. Our findings suggest that both global temperature changes and East Asian monsoons have played crucial roles in floristic diversification within the karst ecosystems in southern China, such that speciation was higher when climate was warmer and wetter. This is the first study to directly demonstrate that past monsoon activity is positively correlated with speciation rate in East Asia. This case study could motivate further investigations to assess the impacts of past environmental changes on the origin and diversification of biodiversity in global karst ecosystems, most of which are under threat. © 2017 John Wiley & Sons Ltd.

  6. The trade-off between safety and efficiency in hydraulic architecture in 31 woody species in a karst area.

    Science.gov (United States)

    Fan, Da-Yong; Jie, Sheng-Lin; Liu, Chang-Cheng; Zhang, Xiang-Ying; Xu, Xin-Wu; Zhang, Shou-Ren; Xie, Zong-Qiang

    2011-08-01

    Karst topography is a special landscape shaped by the dissolution of one or more layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Due to subterranean drainage, overland flow, extraction of water by plants and evapotranspiration, there may be very limited surface water. The hydraulic architecture that plants use to adapt to karst topography is very interesting, but few systematic reports exist. The karst area in southwestern China is unique when compared with other karst areas at similar latitudes, because of its abundant precipitation, with rainfall concentrated in the growing season. In theory, resistance to water-stress-induced cavitation via air seeding should be accompanied by decreased pore hydraulic conductivity and stem hydraulic conductivity. However, evidence for such trade-offs across species is ambiguous. We measured the hydraulic structure and foliar stable carbon isotope ratios of 31 karst woody plants at three locations in Guizhou Province, China, to evaluate the functional coordination between resistance to cavitation and specific conductivity. We also applied phylogenetically independent contrast (PIC) analysis in situations where the inter-species correlations of functional traits may be biased on the potential similarity of closely related species. The average xylem tension measurement, at which 50% of hydraulic conductivity of the plants was lost (Ψ(50)), was only -1.27 MPa. Stem Ψ(50) was positively associated with specific conductance (K(s)) (P sapwood area:leaf area ratio) was negatively correlated with K(s) in both the traditional cross-species correlation and the corresponding PIC correlations (P < 0.01). The characteristics of hydraulic architecture measured in this study showed that karst plants in China are not highly cavitation-resistant species. This study also supports the idea that there may not be an evolutionary trade-off between resistance to cavitation and specific conductivity in woody

  7. Isotope Investigations at an Alpine Karst Aquifer by Means of On-Site Measurements with High Time Resolution and Near Real-Time Data Availability

    International Nuclear Information System (INIS)

    Leis, A.; Plieschnegger, M.; Harum, T.; Stadler, H.; Schmitt, R.; Pelt, A. Van; Zerobin, W.

    2011-01-01

    For numerous hydrological investigations as the characterization of storage and discharge dynamics at karst springs on-site isotopic measurements with high time resolution could improve the significance of the investigations. Conventional isotope ratio mass spectrometers (IRMS) can only be used in laboratories because of their technical complexity. Since a short time more compact laser based instruments, the so called cavity ringdown spectrometers (CRDS) are commercially available. For on-site use of such an instrument several adaptations are necessary. This concerns especially a direct sample injection from the outflow of the spring, because this is originally not intended. The studied alpine and mountainous karst system is located in the so called Northern Calcareous Alps in Austria reaching altitudes up to approx. 2300 masl. The spring is situated in the Salza-valley at an altitude of approximately 650 masl. The investigated karst spring is a typical limestone spring type according to having well developed karst conduits. The isotopic composition of the water samples were measured by using cavity ring-down spectroscopy with a WS-CRDS (Wavelength-Scanned Cavity Ring-Down Spectroscopy) instrument (Picarro, Inc.). In order to adapt the System for on-site isotope measurements at the spring the laser spectrometer was coupled to an automatic injection module for continuous measurements of liquid samples based on a VALCO valve. The device replaces the auto-sampler and allows quasi-continuous injections of a 2 ul-water samples into the Picarro L1102-iso-water analyzer via the Picarro vaporizer module.

  8. Subsidence hazards connected to quarrying activities in a karst area: the case of the Moncalvo sinkhole event (Piedmont, NW Italy

    Directory of Open Access Journals (Sweden)

    Bonetto, Sabrina

    2008-09-01

    Full Text Available Gypsum is an important raw material for constructions and other industrial sectors. In Piedmont (NW Italy, main gypsum bodies are located in the Monferrato area, where large open pits and underground quarries are present. The gypsum-bearing formation outcropping in this area shows typical geological, structural, and hydrogeological features, which affect the quarrying and the related interaction with natural phenomena, human activities, and land use. In particular, gypsum karst has considerable influence on mining operations, as well as mining operations can produce strong impact on gypsum karst. In Monferrato, a specific case of interaction between the quarrying activity and geological, hydrogeological, and territorial setting is represented by the event of water inrush that happened in the Moncalvo underground quarry in association with the development of a surface sinkhole phenomenon.

  9. First definitive record of a stygobiotic fish (Percopsiformes, Amblyopsidae, Typhlichthys from the Appalachians karst region in the eastern United States

    Directory of Open Access Journals (Sweden)

    Matthew L. Niemiller

    2016-11-01

    Full Text Available In the central and eastern United States, cavefishes have been known historically only from the Interior Low Plateau and Ozarks karst regions. Previously, cavefishes were unknown from the Appalachians karst region, which extends from southeastern New York southwestward into eastern Tennessee, northwestern Georgia, and northeastern Alabama. Here we report the discovery of a new population of the amblyopsid cavefish Typhlichthys subterraneus Girard, 1859 from a cave in Catoosa County, Georgia, that significantly extends the known distribution of the species. The cave is located in the Appalachian Valley and Ridge physiographic province and Appalachians karst region, and represents the first definitive report of a stygobiotic fish from the Appalachians karst region. Genetic analyses of one mitochondrial and one nuclear locus from the cavefish indicate this population is closely allied with populations that occur along the western margins of Lookout and Fox mountains in Dade County, Georgia, and populations to the northwest in southern Marion County, Tennessee. It is likely that these populations are also related to those from Wills Valley, DeKalb County, Alabama. The distribution of this new population of T. subterraneus and its close allies pre-dates the emergence of a Tennessee-Coosa River drainage divide in the Pliocene. The potential exists to discover additional populations in caves within the Appalachians karst region in Catoosa County and northward into Hamilton County, Tennessee.

  10. Functions for biomass and basic density of stem, crown and root system of Norway spruce (Picea abies (L.) Karst.) in Denmark

    DEFF Research Database (Denmark)

    Skovsgaard, Jens Peter; Bald, Caroline; Nord-Larsen, Thomas

    2011-01-01

    Models for predicting the biomass of forest trees are becoming increasingly important for assessing forest resources and carbon sequestration in forests. We developed functions for predicting the biomass and basic density of above- and below-ground parts of Norway spruce (Picea abies (L.) Karst.)...

  11. Quantitative Evaluation of Ecosystem Health in a Karst Area of South China

    Directory of Open Access Journals (Sweden)

    Shengzi Chen

    2016-10-01

    Full Text Available The purpose of this study is to propose a GIS-based mechanism for diagnosing karst rocky desertification (KRD ecosystem health. Using the Huajiang Demonstration Area in Guizhou Province as a case study, this research offers a multi-factor indicator system for diagnosing KRD ecosystem health. A set of geologic, environmental, and socio-economic health indicators were developed based on remote sensing images from field-investigation, hydrological, and meteorological monitoring data. With the use of grid GIS technology, this study gives an indicator for diagnosing the spatial expression of desertification at a 5 m × 5 m grid scale. Using spatial overlaying technology based on grid data, the temporal and spatial dynamics of ecosystem health in the Huajiang Demonstration Area were tracked over a 10 year time span. The results of the analysis indicate that ecosystem health in the Huajiang Demonstration Area varies regionally, and has overall improved over time. The proportion of healthy area increased from 3.7% in 2000 to 8.2% in 2010. However, unhealthy and middle-health areas still accounted for 78.7% of the total area by 2010. The most obvious improvement of ecosystem health was in an area where comprehensive control measures for curbing KRD were implemented. These results suggest that comprehensive control of KRD can effectively mitigate ecosystem deterioration and improve ecosystem health in karst regions of South China.

  12. Microbial diversity and impact on carbonate geochemistry across a changing geochemical gradient in a karst aquifer.

    Science.gov (United States)

    Gray, Cassie J; Engel, Annette S

    2013-02-01

    Although microbes are known to influence karst (carbonate) aquifer ecosystem-level processes, comparatively little information is available regarding the diversity of microbial activities that could influence water quality and geological modification. To assess microbial diversity in the context of aquifer geochemistry, we coupled 16S rRNA Sanger sequencing and 454 tag pyrosequencing to in situ microcosm experiments from wells that cross the transition from fresh to saline and sulfidic water in the Edwards Aquifer of central Texas, one of the largest karst aquifers in the United States. The distribution of microbial groups across the transition zone correlated with dissolved oxygen and sulfide concentration, and significant variations in community composition were explained by local carbonate geochemistry, specifically calcium concentration and alkalinity. The waters were supersaturated with respect to prevalent aquifer minerals, calcite and dolomite, but in situ microcosm experiments containing these minerals revealed significant mass loss from dissolution when colonized by microbes. Despite differences in cell density on the experimental surfaces, carbonate loss was greater from freshwater wells than saline, sulfidic wells. However, as cell density increased, which was correlated to and controlled by local geochemistry, dissolution rates decreased. Surface colonization by metabolically active cells promotes dissolution by creating local disequilibria between bulk aquifer fluids and mineral surfaces, but this also controls rates of karst aquifer modification. These results expand our understanding of microbial diversity in karst aquifers and emphasize the importance of evaluating active microbial processes that could affect carbonate weathering in the subsurface.

  13. Litter Decomposition Rate of Karst Ecosystem at Gunung Cibodas, Ciampea Bogor Indonesia

    Directory of Open Access Journals (Sweden)

    Sethyo Vieni Sari

    2016-05-01

    Full Text Available The study aims to know the productivity of litter and litter decomposition rate in karst ecosystem. This study was conducted on three altitude of 200 meter above sea level (masl, 250 masl and 300 masl in karst ecosystem at Gunung Cibodas, Ciampea, Bogor. Litter productivity measurement performed using litter-trap method and litter-bag method was used to know the rate of decomposition. Litter productivity measurement results showed that the highest total of litter productivity measurement results was on altitude of 200 masl (90.452 tons/ha/year and the lowest was on altitude of 300 masl (25.440 tons/ha/year. The litter productivity of leaves (81.425 ton/ha/year showed the highest result than twigs (16.839 ton/ha/year, as well as flowers and fruits (27.839 ton/ha/year. The rate of decomposition was influenced by rainfall. The decomposition rate and the decrease of litter dry weight on altitude of 250 masl was faster than on the altitude of 200 masl and 300 masl. The dry weight was positively correlated to the rate of decomposition. The lower of dry weight would affect the rate of decomposition become slower. The average of litter C/N ratio were ranged from 28.024%--28.716% and categorized as moderate (>25. The finding indicate that the rate of decomposition in karst ecosystem at Gunung Cibodas was slow and based on C/N ratio of litter showed the mineralization process was also slow.

  14. Deformation of evaporites near the Waste Isolation Pilot Plant (WIPP) site

    International Nuclear Information System (INIS)

    Borns, D.J.; Barrows, L.J.; Powers, D.W.; Snyder, R.P.

    1983-03-01

    Layered evaporite units of Ochoan age in the Delaware Basin are 1000 m thick. They are divided into three stratigraphic units (listed in order of increasing age): the Rustler Formation, the Salado Formation, the Castile Formation. These units, especially the Castile, are deformed along portions of the margin of the Delaware Basin and in some areas internal to the basin. Hypotheses of origin of deformation considered are: gravity foundering; gravity sliding; gypsum dehydration; dissolution; and depositional variations. Gravity foundering and sliding are considered the most probable causes of deformation. However, no hypothesis adequately answers why the deformation has a limited areal distribution. A possible explanation would be areal variations in rock strength caused by variations of intergranular water content. Age and timing of deformation are also crucial. Standard stratigraphic arguments based on superposition may not apply to such a highly incompetent material as halite. Gravity foundering could have happened at any time since deposition including the present; gravity sliding would probably have occurred since basin tilting began in the Cenozoic. Deformation could be ongoing. However, the strain rates are such (10 - 16 s - 1 ) that deformation would progress slowly relative to the facility's time frame of 2.5 x 10 5 y. Deformation of Salado units would be minimal ( 4 to 10 6 y to develop. At these strain rates, fractures that connect the fractured anhydrites of the Castile with the middle Salado could not develop. Deformation should not directly jeopardize the facility over the next 2.5 x 10 5 y

  15. Effects of projected climate (2011–50) on karst hydrology and species vulnerability—Edwards aquifer, south-central Texas, and Madison aquifer, western South Dakota

    Science.gov (United States)

    Mahler, Barbara J.; Stamm, John F.; Poteet, Mary F.; Symstad, Amy J.; Musgrove, MaryLynn; Long, Andrew J.; Norton, Parker A.

    2015-12-22

    Karst aquifers—formed by the dissolution of soluble rocks such as limestone—are critical groundwater resources in North America, and karst springs, caves, and streams provide habitat for unique flora and fauna. Springflow and groundwater levels in karst terrane can change greatly over short time scales, and therefore are likely to respond rapidly to climate change. How might the biological communities and ecosystems associated with karst respond to climate change and accompanying changes in groundwater levels and springflow? Sites in two central U.S. regions—the Balcones Escarpment of south-central Texas and the Black Hills of western South Dakota (fig. 1)—were selected to study climate change and its potential effects on the local karst hydrology and ecosystem. The ecosystems associated with the Edwards aquifer (Balcones Escarpment region) and Madison aquifer (Black Hills region) support federally listed endangered and threatened species and numerous State-listed species of concern, including amphibians, birds, insects, and plants. Full results are provided in Stamm and others (2014), and are summarized in this fact sheet.

  16. Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring

    Science.gov (United States)

    Watlet, Arnaud; Kaufmann, Olivier; Triantafyllou, Antoine; Poulain, Amaël; Chambers, Jonathan E.; Meldrum, Philip I.; Wilkinson, Paul B.; Hallet, Vincent; Quinif, Yves; Van Ruymbeke, Michel; Van Camp, Michel

    2018-03-01

    Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip

  17. Changes in Chemical and Isotopic Composition of Groundwater during Long-Term Pumping Test in Brestovica Karst Aquifer

    International Nuclear Information System (INIS)

    Mezga, Kim; Urbanc, Janko

    2011-01-01

    The main aim of the experimental pumping test, which was carried out in the dry summer period in August 2008 for 30 days, was to assess the groundwater resource quantity which could be pumped at the time of the highest water needs for the Slovene Coast and Karst areas. Further, we wanted to test the chemical status of groundwater to assure its suitability for further use and to assess the influence of the Soca River aquifer on this karst aquifer

  18. Isotopic Zonation Within Sulfate Evaporite Mineral Crystals Reveal Quantitative Paleoenvironment Details

    Science.gov (United States)

    Coleman, M.; Rhorssen, M.; Mielke, R. E.

    2008-12-01

    developed a new analytical method [2]. We use a modification of the standard TC/EA continuous-flow protocol to measure both hydrogen and oxygen of water of hydration from the same small sample. We have proved the concept of this new approach by analyzing zones within crystals and individual grains, growing epsomite (magnesium sulfate heptahydrate) in the laboratory and by analysis of natural gypsum evaporites. We are now exploring the effects of varying the controlling parameters. Eventual application to Martian sulfates will reveal amount of water involved in sulfate formation, its isotopic composition(s) and details of the paleo-atmospheric humidity. [1] Gat JR and Gonfiantini R, (Eds) (1981) IAEA Technical Report Series. [2] Rohrssen MK, Brunner B Mielke RE and Coleman M (2008) Analyt. Chem. (in press).

  19. Soil microbial community as a proxy for the ecological service condition in karst soils of SW China

    Science.gov (United States)

    Green, Sophie M.; Dungait, Jennifer A. J.; Zhang, Xinyu; Hawkes, Simon; Donovan, Neil; Barrows, Tim; Buss, Heather; Liu, Taoze; Evershed, Richard; Wen, Xuefa; Hartley, Iain; Song, Zhaoliang; Liu, Hongyan; Tu, Chenglong; Johnes, Penny J.; Meersmans, Jeroen; Guo, Dali; Quine, Tim

    2017-04-01

    Karst is a key landscape covering extensive areas of Southwest China that has undergone rapid intensive land use change and degradation over the last 50 years. Clear evidence of environmental degradation and its damaging consequences for the reduction of intrinsic value of the land for local human populations has led to an increasing focus on landscape rehabilitation. This has included unmanaged abandonment and attempts to re-vegetate denuded surfaces. However, this has achieved limited success and there is a clear need to develop restoration strategies underpinned by robust quantitative and mechanistic understanding of critical zone (CZ) functioning. Thus, a karst Critical Zone Observatory (CZO) was established in June 2016 in Chenqi, Guizhou Province, along a gradient through three levels of human perturbed landscapes: sloping farmland; recovery phase 1 (recently abandoned, within 5 years); and, recovery phase 2 (secondary forest, abandoned > 5 years). We hypothesise that there is a tipping point along the degradation gradient beyond which key biological controls over CZ function are lost, resulting in declining nutrient cycling and rock weathering rates, and increased soil erosion rates. This paper will present preliminary data from the application of the CZ approach using space-for-time substitution. We characterised soil microbial community dynamics along the degradation gradient using geochemical biomarkers and soil properties measured in soil profiles (soil microbes, and pools of soil carbon (C), nitrogen (N) and phosphorus (P), with estimations of soil erosion rates using radionuclide 137Cs/Pb210, within the karst ecosystem to evaluate the status of key ecosystem functions (e.g. nutrient cycling, carbon sequestration, soil stabilisation).

  20. Charaterising water-rock interaction in a mixed carbonate-evaporite karstified aquifer system, Qatar

    Science.gov (United States)

    Thirathititham, R.; Whitaker, F.

    2017-12-01

    Qatar is an arid country, most of the rainfall (80 mm/yr) occurring during intense storms. Surface runoff is endorheic and recharge is facilitated by karst features developed over an extended (c.30 Ma) period of exposure of the carbonate bedrock. In December 2016, we sampled a rare intense rainfall event (41 mm over 3 days), after which waters ponded within low-relief terminal depressions prior to infiltration. We compare the chemistry of these recharge waters with that of ground waters from 76 wells distributed across Qatar to understand the nature and spatial distribution of water-rock interaction. Using Cl- as a conservative tracer for seawater mixing, we calculate concentrations of rock-derived Ca2+, Mg2+ and SO42-. During surface detention, rain chemistry is modified by evaporation and interaction with clays and the surface bedrock over days to weeks. However, groundwater chemistry is dominated by subsurface interaction between recharge waters and the karstified Tertiary aquifers. These include the largely dolomitic Paleocene to Lower Eocene Umm er Radhuma (UER) and overlying Lower Eocene Rus, with the Middle Eocene Abarug limestone forming a locally important aquifer in the south west. Away from coastal areas which show clear evidence of salinisation, TDS of groundwaters in the interior of the peninsula increases from north to south. All groundwaters are significantly enriched in SO42-, but this enrichment is marked greater in the south. This likely reflects the presence of a unit of middle Rus gypsum that in the south of the country confines the Lower Rus and UER aquifers, whilst in the north either gypsum was not deposited or has been dissolved. Waters in the Abarug limestone show limited sulfate enrichment and a 1:1 molar ratio of rock-derived SO42-: Ca2+, but across much of the country both SO42- enrichment and SO42-: Ca2+ molar ratio are significantly higher, the latter reaching 2:1 and suggesting an additional sink for Ca2+. The dolomite aquifer waters

  1. Factors affecting ground-water exchange and catchment size for Florida lakes in mantled karst terrain

    Science.gov (United States)

    Lee, Terrie Mackin

    2002-01-01

    In the mantled karst terrain of Florida, the size of the catchment delivering ground-water inflow to lakes is often considerably smaller than the topographically defined drainage basin. The size is determined by a balance of factors that act individually to enhance or diminish the hydraulic connection between the lake and the adjacent surficial aquifer, as well as the hydraulic connection between the surficial aquifer and the deeper limestone aquifer. Factors affecting ground-water exchange and the size of the ground-water catchment for lakes in mantled karst terrain were examined by: (1) reviewing the physical and hydrogeological characteristics of 14 Florida lake basins with available ground-water inflow estimates, and (2) simulating ground-water flow in hypothetical lake basins. Variably-saturated flow modeling was used to simulate a range of physical and hydrogeologic factors observed at the 14 lake basins. These factors included: recharge rate to the surficial aquifer, thickness of the unsaturated zone, size of the topographically defined basin, depth of the lake, thickness of the surficial aquifer, hydraulic conductivity of the geologic units, the location and size of karst subsidence features beneath and onshore of the lake, and the head in the Upper Floridan aquifer. Catchment size and the magnitude of ground-water inflow increased with increases in recharge rate to the surficial aquifer, the size of the topographically defined basin, hydraulic conductivity in the surficial aquifer, the degree of confinement of the deeper Upper Floridan aquifer, and the head in the Upper Floridan aquifer. The catchment size and magnitude of ground-water inflow increased with decreases in the number and size of karst subsidence features in the basin, and the thickness of the unsaturated zone near the lake. Model results, although qualitative, provided insights into: (1) the types of lake basins in mantled karst terrain that have the potential to generate small and large

  2. Nitrogen isotope compositions and spatial distribution characteristics of soil in the process of karst rocky desertification

    International Nuclear Information System (INIS)

    Luo Xuqiang; Wang Shijie; Wang Chengyuan; Liang Yuhua; Liao Xinrong; Yang Hongyan

    2011-01-01

    Isotopic composition and spatial distribution characteristic of total nitrogen of the surficial soil in karst rocky desertification area, including different types, different grades and different disturbed modes karst rocky desertification within the same small catchment, which belong to the Wangjiazhai peak-cluster depression basin and located in Qingzhen City, Guizhou Province were discussed in this study. Results showed that δ 15 N values of total nitrogen in top soil in yellow soil area were mainly between +0.35‰ ∼ +6.82% with the average of +4.50‰, and between +2.70‰ ∼ +6.50‰ in black calcareous with the average of +4.27‰. In both yellow soil area and black calcareous area, there were no significant difference in the δ 15 N values of total nitrogen on sample lands of rocky desertification at different levels, different ways of interruption and different slope positions, and no obvious difference on the whole (P≤0.05), which is mainly due to the high habitat heterogeneity of karst area. (authors)

  3. Jahani salt diapir, Iran: Hydrogeology, karst features and effect on surroundings environment

    Czech Academy of Sciences Publication Activity Database

    Abirifard, M.; Raeisi, E.; Zarei, M.; Zare, M.; Filippi, Michal; Bruthans, J.; Talbot, J.

    2017-01-01

    Roč. 46, č. 3 (2017), s. 445-457 ISSN 0392-6672 Institutional support: RVO:67985831 Keywords : salt diapir * brine spring * sinkhole * flow model * halite dissolution * salt karst Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.439, year: 2016

  4. Potential Evaporite Biomarkers from the Dead Sea

    Science.gov (United States)

    Morris, Penny A.; Wentworth, Susan J.; Thomas-Keprta, Kathie; Allen, Carlton C.; McKay, David S.

    2001-01-01

    The Dead Sea is located on the northern branch of the African-Levant Rift systems. The rift system, according to one model, was formed by a series of strike slip faults, initially forming approximately two million years ago. The Dead Sea is an evaporite basin that receives freshwater from springs and from the Jordan River. The Dead Sea is different from other evaporite basins, such as the Great Salt Lake, in that it possesses high concentrations of magnesium and has an average pH of 6.1. The dominant cation in the Great Salt Lake is sodium, and the pH is 7.7. Calcium concentrations are also higher in the Dead Sea than in the Great Salt Lake. Both basins are similar in that the dominant anion is chlorine and the salinity levels are approximately 20 %. Other common cations that have been identified from the waters of the Dead Sea and the Great Salt Lake include sodium and potassium. A variety of Archea, Bacteria, and a single genus of a green algal, Dunaliella, has been described from the Dead Sea. Earlier studies concentrated on microbial identification and analysis of their unique physiology that allows them to survive in this type of extreme environment. Potential microbial fossilization processes, microbial fossils, and the metallic ions associated with fossilization have not been studied thoroughly. The present study is restricted to identifying probable microbial morphologies and associated metallic ions. XRD (X Ray Diffraction) analysis indicates the presence of halite, quartz, and orthoclase feldspar. In addition to these minerals, other workers have reported potassium chloride, magnesium bromide, magnesium chloride, calcium chloride, and calcium sulfate. Halite, calcium sulfate, and orthoclase were examined in this report for the presence of microbes, microbially induced deposits or microbial alteration. Neither the gypsum nor the orthoclase surfaces possesses any obvious indications of microbial life or fossilization. The sand-sized orthoclase particles are

  5. Distribution of polycyclic aromatic hydrocarbons in Datuo karst Tiankeng of South China.

    Science.gov (United States)

    Theodore, Oramah I; Qi, Shihua; Kong, Xiangsheng; Liu, Huafeng; Li, Jun; Li, Jie; Wang, Xiangqing; Wang, Yinhui

    2008-10-01

    Levels of polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils of Datuo karst Tiankeng (large sinkholes) in South China with the use of a gas chromatography-mass spectroscopy (GC-MS) system. This paper provides data on the levels and distribution of PAHs from the top to the bottom of the Datuo karst Tiankeng. The results showed that the sum of the 16 EPA priority PAHs from the sampled locations from top to bottom had a relative increment in PAHs concentration. summation operatorPAHs ranged from 16.93 ng/g to 68.07 ng/g with a mean concentration of 42.15 ng/g. The correlated results showed the bottom of the large sinkhole, which accounts for the higher concentrations, probably acts like a trap for the PAHs. Thus, the low evaporation rate at the bottom may play a key role in controlling the high concentration of PAHs at the bottom.

  6. Social developmnet of ecologically sensitive rural areas: Case studies of the Moravian Karst (Czech Republic) and the Devetashko Plato (Bulgaria)

    Czech Academy of Sciences Publication Activity Database

    Zapletalová, Jana; Stefanová, D.; Vaishar, Antonín; Stefanov, P.; Dvořák, Petr; Tcherkezova, E.

    3-4, 3-4 (2016), s. 65-84 ISSN 0204-7209 Institutional support: RVO:68145535 Keywords : social development * rural sensitive areas * Devetashko Plato * Bulgaria * Moravian karst - Czech Republic Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Cultural and economic geography http://geoproblems.eu/wp-content/uploads/2017/04/2016_34/4_zapletalova.pdf

  7. Human impact on Karst: the example of Lusaka (Zambia.

    Directory of Open Access Journals (Sweden)

    De Waele Jo

    2003-01-01

    Full Text Available Lusaka, the capital of Zambia with over 2,000,000 inhabitants, is built on an extensive plateau composed mainly of schists and dolomitic marbles, constituting a very important aquifer that provides the city with almost half of its drinking water needs. Recent demographic growth, leading to uncontrolled urban expansion, and mismanagement of the water resource and of urban waste has lead, in the past 20 years, to an overexploitation of the aquifer and to a generalised water quality depletion, putting in serious danger the future social and economical development of the capital. This third world city has, for these reasons, become a terrifying example of human impact on a vulnerable karst environment, and if no measures will be taken in the very near future, quality of life in the city will be at serious risk.

  8. Estimating the proportion of groundwater recharge from flood events in relation to total annual recharge in a karst aquifer

    Science.gov (United States)

    Dvory, N. Z.; Ronen, A.; Livshitz, Y.; Adar, E.; Kuznetsov, M.; Yakirevich, A.

    2017-12-01

    Sustainable groundwater production from karstic aquifers is primarily dictated by its recharge rate. Therefore, in order to limit over-exploitation, it is essential to accurately quantify groundwater recharge. Infiltration during erratic floods in karstic basins may contribute substantial amount to aquifer recharge. However, the complicated nature of karst systems, which are characterized in part by multiple springs, sinkholes, and losing/gaining streams, present a large obstacle to accurately assess the actual contribution of flood water to groundwater recharge. In this study, we aim to quantify the proportion of groundwater recharge during flood events in relation to the annual recharge for karst aquifers. The role of karst conduits on flash flood infiltration was examined during four flood and artificial runoff events in the Sorek creek near Jerusalem, Israel. The events were monitored in short time steps (four minutes). This high resolution analysis is essential to accurately estimating surface flow volumes, which are of particular importance in arid and semi-arid climate where ephemeral flows may provide a substantial contribution to the groundwater reservoirs. For the present investigation, we distinguished between direct infiltration, percolation through karst conduits and diffused infiltration, which is most affected by evapotranspiration. A water balance was then calculated for the 2014/15 hydrologic year using the Hydrologic Engineering Center - Hydrologic Modelling System (HEC-HMS). Simulations show that an additional 8% to 24% of the annual recharge volume is added from runoff losses along the creek that infiltrate through the karst system into the aquifer. The results improve the understanding of recharge processes and support the use of the proposed methodology for quantifying groundwater recharge.

  9. Relative importance of natural and anthropogenic factors influencing karst rocky desertification

    Science.gov (United States)

    Xu, Erqi; Zhang, Hongqi

    2017-04-01

    As the most severe ecological issue in southwest China, karst rocky desertification (KRD) has both threatened and constrained regional sustainable development. Comprehensively understanding the relationship between the evolution of KRD and relevant driving data would provide more information to combat KRD in such complex karst environments. Past studies have been limited in quantifying the relative importance of driving factors influencing fine-scale KRD evolution, and have also lacked insight into their interactive impacts. To address these issues, we have used geographical information system techniques and a geographical detector model to explore the spatial consistency of driving factors and their interactions in relation to the evolution of KRD. Changshun County in China was selected as a representative area for the study. Nine relevant driving factors, including both natural and anthropogenic factors, were studied in regard to their relationships with KRD transformation between 2000 and 2010. Our results demonstrate the relative importance of driving data in influencing the improvement and deterioration of KRD. Lithology, soil type and road influence are identified as the leading factors. Interestingly, to our study at least, there is no significant difference between the impacts of natural and anthropogenic factors influencing KRD improvement, and even natural factors have a higher impact on KRD deterioration. Factors were found to enhance the influence of each other for KRD transformation. In particular, the results show a non-linearly enhanced effect between driving factors, which significantly aggravates KRD. New information found in our study helps to effectively control and restore areas afflicted by KRD.

  10. Delineating Potential Karst Water-Bearing Structures based on Resistivity Anomalies and Microtremor Analyses-A Case Study in Yunnan Province, China

    Science.gov (United States)

    Gan, F.; Su, C.; Liu, W.; Zhao, W.

    2016-12-01

    Heterogeneity, anisotropy and rugged landforms become challenges for geophysicists to locate drilling site by water-bearing structure profiling in Karst region. If only one geophysical method is used to achieve this objective, low resistivity anomalies deduced to be water-rich zones could actually be zones rich in marl and shale. In this study, integrated geophysical methods were used to locate a favorable drilling position for the provision of karst water to Juede village, which had been experiencing severe water shortages over a prolonged period. According to site conditions and hydrogeological data, appropriate geophysical profiles were conducted, approximately perpendicular to the direction of groundwater flow. In general, significant changes in resistivity occur between water-filled caves/ fractures and competent rocks. Thus, electrical and electromagnetic methods have been widely applied to search for karst groundwater indirectly. First, electrical resistivity tomography was carried out to discern shallow resistivity distributions within the profile where the low resistivity anomalies were of most interest. Second, one short profile of audio-frequency magnetotelluric survey was used to ascertain the vertical and horizontal extent of these low resistivity anomalies. Third, the microtremor H/V spectral ratio method was applied to identify potential water-bearing structures from low resistivity anomalies and to differentiate these from the interference of marl and shale with low resistivity. Finally, anomalous depths were estimated by interpreting Schlumberger sounding data to determine an optimal drilling site. The study shows that karst hydrogeology and geophysical methods can be effectively integrated for the purposes of karst groundwater exploration.

  11. Contamination risk and drinking water protection for a large-scale managed aquifer recharge site in a semi-arid karst region, Jordan

    Science.gov (United States)

    Xanke, Julian; Liesch, Tanja; Goeppert, Nadine; Klinger, Jochen; Gassen, Niklas; Goldscheider, Nico

    2017-09-01

    Karst aquifers in semi-arid regions are particularly threatened by surface contamination, especially during winter seasons when extremely variable rainfall of high intensities prevails. An additional challenge is posed when managed recharge of storm water is applied, since karst aquifers display a high spatial variability of hydraulic properties. In these cases, adapted protection concepts are required to address the interaction of surface water and groundwater. In this study a combined protection approach for the surface catchment of the managed aquifer recharge site at the Wala reservoir in Jordan and the downstream Hidan wellfield, which are both subject to frequent bacteriological contamination, is developed. The variability of groundwater quality was evaluated by correlating contamination events to rainfall, and to recharge from the reservoir. Both trigger increased wadi flow downstream of the reservoir by surface runoff generation and groundwater seepage, respectively. A tracer test verified the major pathway of the surface flow into the underground by infiltrating from pools along Wadi Wala. An intrinsic karst vulnerability and risk map was adapted to the regional characteristics and developed to account for the catchment separation by the Wala Dam and the interaction of surface water and groundwater. Implementation of the proposed protection zones for the wellfield and the reservoir is highly recommended, since the results suggest an extreme contamination risk resulting from livestock farming, arable agriculture and human occupation along the wadi. The applied methods can be transferred to other managed aquifer recharge sites in similar karstic environments of semi-arid regions.

  12. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    Karst aquifers are highly heterogeneous and characterized by a duality of recharge (concentrated; fast versus diffuse; slow) and a duality of flow which directly influences groundwater flow and spring responses. Given this heterogeneity in flow and infiltration, karst aquifers do not always obey standard hydraulic laws. Therefore the assessment of their vulnerability reveals to be challenging. Studies have shown that vulnerability of aquifers is highly governed by recharge to groundwater. On the other hand specific parameters appear to play a major role in the spatial and temporal distribution of infiltration on a karst system, thus greatly influencing the discharge rates observed at a karst spring, and consequently the vulnerability of a spring. This heterogeneity can only be depicted using an integrated numerical model to quantify recharge spatially and assess the spatial and temporal vulnerability of a catchment for contamination. In the framework of a three-year PEER NSF/USAID funded project, the vulnerability of a karst catchment in Lebanon is assessed quantitatively using a numerical approach. The aim of the project is also to refine actual evapotranspiration rates and spatial recharge distribution in a semi arid environment. For this purpose, a monitoring network was installed since July 2014 on two different pilot karst catchment (drained by Qachqouch Spring and Assal Spring) to collect high resolution data to be used in an integrated catchment numerical model with MIKE SHE, DHI including climate, unsaturated zone, and saturated zone. Catchment characterization essential for the model included geological mapping and karst features (e.g., dolines) survey as they contribute to fast flow. Tracer experiments were performed under different flow conditions (snow melt and low flow) to delineate the catchment area, reveal groundwater velocities and response to snowmelt events. An assessment of spring response after precipitation events allowed the estimation of the

  13. Changes in Chemical and Isotopic Composition of Groundwater During a Long Term Pumping Test in Brestovica Karst Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Mezga, K.; Urbanc, J. [Geological Survey of Slovenia, Department of Hydrogeology, Ljubljana (Slovenia)

    2013-07-15

    A pumping test of the Klarici water supply near Brestovica was performed in August 2008, in order to determine the karst groundwater resource capacity. Groundwater was pumped for a month with a total capacity of 470 L/s. During the experiment, sampling for chemical and isotopic composition of groundwater and surface water was carried out. Intensive pumping in dry meteorological conditions caused a lowering of the water table and changes in the chemical and isotopic composition of pumped water. Local meteoric waters are infiltrated into the aquifer at a lower mean altitude; therefore the {delta}{sup 18}O is enriched with the heavy oxygen isotope. The duration of pumping resulted in changes in the isotopic composition of oxygen due to a greater impact of the intergranular Soca River aquifer on the karst aquifer. On the basis of isotope composition it was possible to quantify the impact of the Soca River on the karst aquifer. (author)

  14. Water Flow in Karst Aquifer Considering Dynamically Variable Saturation Conduit

    Science.gov (United States)

    Tan, Chaoqun; Hu, Bill X.

    2017-04-01

    The karst system is generally conceptualized as dual-porosity system, which is characterized by low conductivity and high storage continuum matrix and high conductivity and quick flow conduit networks. And so far, a common numerical model for simulating flow in karst aquifer is MODFLOW2005-CFP, which is released by USGS in 2008. However, the steady-state approach for conduit flow in CFP is physically impractical when simulating very dynamic hydraulics with variable saturation conduit. So, we adopt the method proposed by Reimann et al. (2011) to improve current model, in which Saint-Venant equations are used to model the flow in conduit. Considering the actual background that the conduit is very big and varies along flow path and the Dirichlet boundary varies with rainfall in our study area in Southwest China, we further investigate the influence of conduit diameter and outflow boundary on numerical model. And we also analyze the hydraulic process in multi-precipitation events. We find that the numerical model here corresponds well with CFP for saturated conduit, and it could depict the interaction between matrix and conduit during very dynamic hydraulics pretty well compare with CFP.

  15. Hydraulic characterisation of karst systems with man-made tracers; Hydraulische Charakterisierung von Karstsystemen mit kuenstlichen Tracern

    Energy Technology Data Exchange (ETDEWEB)

    Werner, A.

    1998-07-01

    Tracer experiments using man-made tracers are common in hydrogeological exploration of groundwater aquifers in karst systems. In the present investigation, a convection-dispersion model (multidispersion model with consideration of several flow paths) and a single-cleft model (consideration of the diffusion between the cleft and the surrounding rock matrix) were used for evaluating tracer experiments in the main hydrological system of the saturated zone of karst systems. In addition to these extended analytical solutions, a numerical transport model was developed for investigating the influence of the transient flow rate on the flow and transport parameters. Comparative evaluations of the model approaches for the evaluation of tracer experiments were made in four different karst systems: Danube-Aach, Paderborn, Slowenia and Lurbach, of which the Danube-Aach system was considered as the most important. The investigation also comprised three supplementary experiments in order to enable a complete hydraulic characterisation of the system. (orig./SR) [Deutsch] Tracerversuche mit kuenstlichen Tracern sind eine haeufig eingesetzte Methode zur hydrogeologischen Erkundung von Karstgrundwasserleitern. In der vorliegenden Arbeit werden fuer die Auswertung von Tracerversuchen im Hauptfliesssystem der gesaettigten Zone von Karstsystemen ein Konvektion-Dispersions-Modell (Multi-Dispersions-Modell: Beruecksichtigung mehrerer Fliesswege) und vergleichend ein Einzelkluftmodell (Beruecksichtigung der Diffusion zwischen Kluft und umgebender Gesteinsmatrix) eingesetzt. Zusaetzlich zu diesen erweiterten analytischen Loesungen wurde ein numerisches Transportmodell entwickelt, welches ermoeglicht, den Einfluss der instationaeren Fliessrate auf die Stroemungs- und Transportparameter zu ueberpruefen. Die vergleichende Anwendung der Modellansaetze fuer die Auswertung von Tracerversuchen erfolgte in den vier verschiedenen Karstsystemen Donau-Aach, Paderborn, Slowenien und Lurbachsystem. Der

  16. Response of dissolved inorganic carbon (DIC) and δ13CDIC to changes in climate and land cover in SW China karst catchments

    Science.gov (United States)

    Zhao, Min; Liu, Zaihua; Li, Hong-Chun; Zeng, Cheng; Yang, Rui; Chen, Bo; Yan, Hao

    2015-09-01

    Monthly hydrochemical data and δ13C of dissolved inorganic carbon (DIC) in karst water samples from September 2007 to October 2012 were obtained to reveal the controlling mechanisms on DIC geochemistry and δ13CDIC under different conditions of climate and land cover in three karst catchments: Banzhai, Dengzhanhe and Chenqi, in Guizhou Province, SW China. DIC of karst water at the Banzhai site comes mainly from carbonate dissolution under open system conditions with soil CO2 produced by root respiration and organic carbon decomposition with lowest δ13C values under its dense virgin forest coverage. Weaker carbonate bedrock dissolution due to sparse and thin soil cover results in lower δ13CDIC, pCO2, DIC and EC, and lower cation and anion concentrations. At the Chenqi site, larger soil CO2 input from a thick layer of soil results in high pCO2 and DIC, and low pH, SIc and δ13CDIC in the karst water. At the Dengzhanhe site, a lesser soil CO2 input due to stronger karst rock desertification and strong gypsum dissolution contribute to higher δ13CDIC, high EC and high cation and anion concentrations. Soil CO2 inputs, controlled by biological activity and available soil moisture, carbonate bedrock dissolution, dilution and degassing effects, vary seasonally following rainfall and temperature changes. Consequently, there are seasonal cycles in hydrochemistry and δ13CDIC of the karst water, with high pCO2 and low pH, EC, SIc, and δ13CDIC values in the warm and rainy seasons, and vice versa during the cold and dry seasons. A strongly positive shift (>3‰) in δ13CDIC occurred in the drought year, 2011, indicating that δ13CDIC in groundwater systems can be an effective indicator of environmental and/or climate changes.

  17. Quantifying the magnitude and spatiotemporal variation of aquatic CO2 fluxes in a sub-tropical karst catchment, Southwest China

    Science.gov (United States)

    Ding, Hu; Waldron, Susan; Newton, Jason; Garnett, Mark H.

    2017-04-01

    The role played by rivers in regional and global C budgets is receiving increasing attention. A large portion of the carbon transported via inland waters is returned to the atmosphere by carbon dioxide evasion from rivers and lakes. Karst landscapes represent an important C store on land, and are also considered to play an important role in climate regulation by consuming atmospheric CO2 during chemical weathering. However, we cannot be certain how effective this sink is if we do not know how efficiently the rivers draining karst landscapes remobilise weathered C to the atmosphere as CO2. pCO2 in karst waters is generally greater than atmospheric equilibrium, indicating that there can be a net CO2 efflux to the atmosphere. However, measurement confirming this and quantifying flux rates has been rarely conducted. Using a floating chamber method, in 2016 we directly measured CO2 fluxes from spatially distributed freshwaters (springs, sinkholes, streams and reservoirs/ponds) in the Houzhai Catchment, a karst region in SW China. Fluxes ranged from -0.5 to +267.4 μmol CO2 m-2s-1, and most sites showed seasonal variations with higher CO2 efflux rates in the wet (April - September) than dry season (October - March). There was a significant positive relationship between CO2 efflux and flow velocity, indicating that hydraulic controls on CO2 efflux from flowing water are important, while for water with little movement (sinkholes and reservoirs/ponds), pCO2 appears a more important control on efflux rates. Conditions similar to this study area may exist in many sub-tropical rivers that drain karst landscapes in South China. These waters are rich in DIC which can be an order of magnitude greater than some non-karst catchments. The large DIC pool has the potential to be a considerable source of free CO2 to the atmosphere. Considering that carbonate lithology covers a significant part of the Earth's surface, CO2 evasion in fluvial water from these regions is expected to

  18. Karst Aquifer Recharge: A Case History of over Simplification from the Uley South Basin, South Australia

    Directory of Open Access Journals (Sweden)

    Nara Somaratne

    2015-02-01

    Full Text Available The article “Karst aquifer recharge: Comments on ‘Characteristics of Point Recharge in Karst Aquifers’, by Adrian D. Werner, 2014, Water 6, doi:10.3390/w6123727” provides misrepresentation in some parts of Somaratne [1]. The description of Uley South Quaternary Limestone (QL as unconsolidated or poorly consolidated aeolianite sediments with the presence of well-mixed groundwater in Uley South [2] appears unsubstantiated. Examination of 98 lithological descriptions with corresponding drillers’ logs show only two wells containing bands of unconsolidated sediments. In Uley South basin, about 70% of salinity profiles obtained by electrical conductivity (EC logging from monitoring wells show stratification. The central and north central areas of the basin receive leakage from the Tertiary Sand (TS aquifer thereby influencing QL groundwater characteristics, such as chemistry, age and isotope composition. The presence of conduit pathways is evident in salinity profiles taken away from TS water affected areas. Pumping tests derived aquifer parameters show strong heterogeneity, a typical characteristic of karst aquifers. Uley South QL aquifer recharge is derived from three sources; diffuse recharge, point recharge from sinkholes and continuous leakage of TS water. This limits application of recharge estimation methods, such as the conventional chloride mass balance (CMB as the basic premise of the CMB is violated. The conventional CMB is not suitable for accounting chloride mass balance in groundwater systems displaying extreme range of chloride concentrations and complex mixing [3]. Over simplification of karst aquifer systems to suit application of the conventional CMB or 1-D unsaturated modelling as described in Werner [2], is not suitable use of these recharge estimation methods.

  19. Characterization of the hydrogeology of the sacred Gihon Spring, Jerusalem: a deteriorating urban karst spring

    Science.gov (United States)

    Amiel, Ronit Benami; Grodek, Tamir; Frumkin, Amos

    2010-09-01

    The Gihon Spring, Jerusalem, is important for the major monotheistic religions. Its hydrogeology and hydrochemistry is studied here in order to understand urbanization effects on karst groundwater resources, and promote better water management. High-resolution monitoring of the spring discharge, temperature and electrical conductivity, was performed, together with chemical and bacterial analysis. All these demonstrate a rapid response of the spring to rainfall events and human impact. A complex karst system is inferred, including conduit flow, fissure flow and diffuse flow. Electrical conductivity, Na+ and K+ values (2.0 mS/cm, 130 and 50 mg/l respectively) are very high compared to other nearby springs located at the town margins (0.6 mS/cm, 15 and <1 mg/l respectively), indicating considerable urban pollution in the Gihon area. The previously cited pulsating nature of the spring was not detected during the present high-resolution monitoring. This phenomenon may have ceased due to additional water sources from urban leakage and irrigation feeding the spring. The urbanization of the recharge catchment thus affects the spring water dramatically, both chemically and hydrologically. Appropriate measures should therefore be undertaken to protect the Gihon Spring and other karst aquifers threatened by rapid urbanization.

  20. Hydrology and Hydraulic Properties of a Bedded Evaporite Formation

    International Nuclear Information System (INIS)

    BEAUHEIM, RICHARD L.; ROBERTS, RANDALL M.

    2000-01-01

    The Permian Salado Formation in the Delaware Basin of New Mexico is an extensively studied evaporite deposit because it is the host formation for the Waste Isolation Pilot Plant, a repository for transuranic wastes. Geologic and hydrologic studies of the Salado conducted since the mid-1970's have led to the development of a conceptual model of the hydrogeology of the formation that involves far-field permeability in anhydrite layers and at least some impure halite layers. Pure halite layers and some impure halite layers may not possess an interconnected pore network adequate to provide permeability. Pore pressures are probably very close to lithostatic pressure. In the near field around an excavation, dilation, creep, and shear have created and/or enhanced permeability and decreased pore pressure. Whether flow occurs in the far field under natural gradients or only after some threshold gradient is reached is unknown. If far-field flow does occur, mean pore velocities are probably on the order of a meter per hundreds of thousands to tens of millions of years. Flow dimensions inferred from most hydraulic-test responses are subradial, which is believed to reflect channeling of flow through fracture networks, or portions of fractures, that occupy a diminishing proportion of the radially available space, or through percolation networks that are not ''saturated'' (fully interconnected). This is probably related to the directional nature of the permeability created or enhanced by excavation effects. Inferred values of permeability cannot be separated from their associated flow dimensions. Therefore, numerical models of flow and transport should include heterogeneity that is structured to provide the same flow dimensions as are observed in hydraulic tests. Modeling of the Salado Formation around the WIPP repository should also include coupling between hydraulic properties and the evolving stress field because hydraulic properties change as the stress field changes

  1. Bacterial and Archaeal Lipids Recovered from Subsurface Evaporites of Dalangtan Playa on the Tibetan Plateau and Their Astrobiological Implications

    Science.gov (United States)

    Cheng, Ziye; Xiao, Long; Wang, Hongmei; Yang, Huan; Li, Jingjing; Huang, Ting; Xu, Yi; Ma, Nina

    2017-11-01

    Qaidam Basin (Tibetan Plateau) is considered an applicable analogue to Mars with regard to sustained extreme aridity and abundant evaporites. To investigate the possibility of the preservation of microbial lipids under these Mars analog conditions, we conducted a mineralogical and organic geochemistry study on samples collected from two Quaternary sections in Dalangtan Playa, northwestern Qaidam Basin, which will enhance our understanding of the potential preservation of molecular biomarkers on Mars. Two sedimentary units were identified along two profiles: one salt unit characterized by a predominance of gypsum and halite, and one detrital unit with a decrease of gypsum and halite and enrichment in siliciclastic minerals. Bacterial fatty acids and archaeal acyclic diether and tetraether membrane lipids were detected, and they varied throughout the sections in concentration and abundance. Bacterial and archaeal biomolecules indicate a dominance of Gram-positive bacteria and halophilic archaea in this hypersaline ecosystem that is similar to those in other hypersaline environments. Furthermore, the abundance of bacterial lipids decreases with the increase of salinity, whereas archaeal lipids showed a reverse trend. The detection of microbial lipids in hypersaline environments would indicate, for example on Mars, a high potential for the detection of microbial biomarkers in evaporites over geological timescales.

  2. Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring

    Directory of Open Access Journals (Sweden)

    A. Watlet

    2018-03-01

    Full Text Available Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1 upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2 deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3 a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of

  3. Landslides, floods and sinkholes in a karst environment: the 1-6 September 2014 Gargano event, southern Italy

    Science.gov (United States)

    Martinotti, Maria Elena; Pisano, Luca; Marchesini, Ivan; Rossi, Mauro; Peruccacci, Silvia; Brunetti, Maria Teresa; Melillo, Massimo; Amoruso, Giuseppe; Loiacono, Pierluigi; Vennari, Carmela; Vessia, Giovanna; Trabace, Maria; Parise, Mario; Guzzetti, Fausto

    2017-03-01

    In karst environments, heavy rainfall is known to cause multiple geohydrological hazards, including inundations, flash floods, landslides and sinkholes. We studied a period of intense rainfall from 1 to 6 September 2014 in the Gargano Promontory, a karst area in Puglia, southern Italy. In the period, a sequence of torrential rainfall events caused severe damage and claimed two fatalities. The amount and accuracy of the geographical and temporal information varied for the different hazards. The temporal information was most accurate for the inundation caused by a major river, less accurate for flash floods caused by minor torrents and even less accurate for landslides. For sinkholes, only generic information on the period of occurrence of the failures was available. Our analysis revealed that in the promontory, rainfall-driven hazards occurred in response to extreme meteorological conditions and that the karst landscape responded to the torrential rainfall with a threshold behaviour. We exploited the rainfall and the landslide information to design the new ensemble-non-exceedance probability (E-NEP) algorithm for the quantitative evaluation of the possible occurrence of rainfall-induced landslides and of related geohydrological hazards. The ensemble of the metrics produced by the E-NEP algorithm provided better diagnostics than the single metrics often used for landslide forecasting, including rainfall duration, cumulated rainfall and rainfall intensity. We expect that the E-NEP algorithm will be useful for landslide early warning in karst areas and in other similar environments. We acknowledge that further tests are needed to evaluate the algorithm in different meteorological, geological and physiographical settings.

  4. An Efficient Upscaling Process Based on a Unified Fine-scale Multi-Physics Model for Flow Simulation in Naturally Fracture Carbonate Karst Reservoirs

    KAUST Repository

    Bi, Linfeng

    2009-01-01

    The main challenges in modeling fluid flow through naturally-fractured carbonate karst reservoirs are how to address various flow physics in complex geological architectures due to the presence of vugs and caves which are connected via fracture networks at multiple scales. In this paper, we present a unified multi-physics model that adapts to the complex flow regime through naturally-fractured carbonate karst reservoirs. This approach generalizes Stokes-Brinkman model (Popov et al. 2007). The fracture networks provide the essential connection between the caves in carbonate karst reservoirs. It is thus very important to resolve the flow in fracture network and the interaction between fractures and caves to better understand the complex flow behavior. The idea is to use Stokes-Brinkman model to represent flow through rock matrix, void caves as well as intermediate flows in very high permeability regions and to use an idea similar to discrete fracture network model to represent flow in fracture network. Consequently, various numerical solution strategies can be efficiently applied to greatly improve the computational efficiency in flow simulations. We have applied this unified multi-physics model as a fine-scale flow solver in scale-up computations. Both local and global scale-up are considered. It is found that global scale-up has much more accurate than local scale-up. Global scale-up requires the solution of global flow problems on fine grid, which generally is computationally expensive. The proposed model has the ability to deal with large number of fractures and caves, which facilitate the application of Stokes-Brinkman model in global scale-up computation. The proposed model flexibly adapts to the different flow physics in naturally-fractured carbonate karst reservoirs in a simple and effective way. It certainly extends modeling and predicting capability in efficient development of this important type of reservoir.

  5. Interaction of Extreme Halophilic Archaea With the Evaporites of the Solar Salterns Guerrero Negro Baja California, Mexico

    Science.gov (United States)

    Tamez, P.; Lopez-Cortés, A.

    2008-12-01

    Hypersaline environments have been significant reservoirs for the long-term evolution of specifically adapted microorganisms. Characterized to have higher salt concentrations (up to 35 g/L), they are worldwide distributed and have a commercial significance. Exportadora de Sal, Guerrero Negro, Mexico has a multipond salterns system designed to harvest common salt (NaCl) from sea water. To achieve this purpose, sea water is pumped through a set of shallow ponds where water evaporates and salts concentrate. Sequential precipitation of CaCO3, CaSO4 2H2O and NaCl occurs in a mineral formations call it evaporites. In the interior of those gypsum-encrusted and halite-encrusted minerals, communities of extremely salt-loving archaea prosper. Previous studies have showed the influence of Haloarchaeal cells in the formation of larger fluid inclusions than crystals formed in sterile salt solutions. S-layer envelopes and cells of Haloarcula strain SP8807 contributed to the nucleation of new crystals of NaCl. Given the significance of the scope in phylogenetic archaeal diversity research, this study had a polyphasic approach. SEM micrographs from a 21- 31% (w/v) gradient salt multipond system evaporites, gave an insight profile of the extreme halophilic archaeal communities thriving in the surface of the gypsum and halite evaporites. Halite crystals were form after 21 days of incubation in solid medium with archaeal cells. Both culture and non-culture dependent methods, Nested-PCR-DGGE analysis and sequencing of 16S rDNA amplified fragment genes from environmental samples and isolated strains were used for this purpose. We isolate three strains from Pond 9 (21.07% total salt concentration) and one strain from Cristallizer 20 (25.15% total salt concentration). 16S rDNA signaling gave 99% of similarity with Halogeometricum borinquense, sequence AF002984, two other strains were 99% of similarity with Halobacterium salinarum, sequence AJ496185 these strains shown different colony

  6. Preliminary characterization of an alpine karst aquifer in a complex geological setting using the KARSYS approach. Picos de Europa, North Spain

    Science.gov (United States)

    Ballesteros, Daniel; Malard, Arnauld; Jeannin, Pierre-Yves; Jiménez-Sánchez, Montserrat; García-Sansegundo, Joaquín; Meléndez, Mónica; Sendra, Gemma

    2013-04-01

    Research applied to karst aquifers linked to a homogeneous limestone in high mountain areas affected by several tectonic events is a hard task, due to methodological constraints and the uncertainties of the geological data. The KARSYS approach (Jeannin et al. 2012) is based on the combination of existing geological data and basic principles of karst hydraulic, allowing for characterizing the geometry of an aquifer considering a smaller amount of data than other methods. The Picos de Europa (North Spain) is an alpine karst massif with a surface area of 700 km2, peaks up to 2,648 m and fluvial gorges up to 2,000 m deep, including about 270 km of cave passage. The bedrock is mainly composed of Ordovician quartzite covered by massive Carboniferous limestone and is affected by two systems of thrusts and other faults. The most of the geological structures are from Variscan orogeny (Carboniferous in age), some of them could be originated or modified during the Permian-Mesozoic extensional episode, and the others were originated or reactivated during the Alpine Orogeny. Therefore, the Picos de Europa can be considered as a complex geological environment in which usual hydrogeological methods are difficult to use. The aim of this study is to characterize the geometry of the Picos de Europa aquifers applying the KARSYS approach. The approach includes: 1) the identification of aquifer and aquiclude formations; 2) the inventory of the main springs; 3) the establishment of a 3D geological model, focused on the aquifer boundaries; 4) the implementation of the hydraulic features within the 3D model and the delineation of the karst system. The main aquifer of the Picos de Europa is developed within the Carboniferous limestone and displays a complex geometry generally limited and divided into several unconfined groundwater bodies by Ordovician to Carboniferous rocks related to the thrusts. The lowest limit of the aquifer is marked by the N-dipping detachment level of the thrusts

  7. The challenge and future of rocky desertification control in karst areas in southwest China

    Science.gov (United States)

    Zhang, J. Y.; Dai, M. H.; Wang, L. C.; Zeng, C. F.; Su, W. C.

    2016-01-01

    Karst rocky desertification occurs after vegetation deteriorates as a result of intensive land use, which leads to severe water loss and soil erosion and exposes basement rocks, creating a rocky landscape. Karst rocky desertification is found in humid areas in southwest China, the region most seriously affected by rocky desertification in the world. In order to promote ecological restoration and help peasants out of poverty, the Chinese government carried out the first phase of a rocky desertification control project from 2006 to 2015, which initially contained the expansion of rocky desertification. Currently, the Chinese government is prepared to implement the second phase of the rocky desertification control project, and therefore it is essential to summarise the lessons learned over the last 10 years of the first phase. In this paper, we analyse the driving social and economic factors behind rocky desertification, summarise the scientific research on rocky desertification in the region, and finally identify the main problems facing rocky desertification control. In addition, we put forward several policy suggestions that take into account the perspective of local peasants, scientific research, and China's economic development and urbanisation process. These suggestions include promoting the non-agriculturalization of household livelihoods, improving ecological compensation, strengthening the evaluation of rocky desertification control and dynamic monitoring, and strengthening research on key ecological function recovery technologies and supporting technologies.

  8. Fluviokarst and classical karst: Examples from the Dinarics (Krk Island, Northern Adriatic, Croatia)

    Science.gov (United States)

    Benac, Čedomir; Juračić, Mladen; Matičec, Dubravko; Ružić, Igor; Pikelj, Kristina

    2013-02-01

    In order to contribute to the debate on the role of fluvial erosion in the shaping of karst, two nearby areas with different karstic landscapes were compared. Areas A and B are located relatively close to each other on the southern side of the Krk Island (Adriatic Sea, Croatia). Both areas are composed of similar limestone with a very high CaCO3 content. Area A is a typical doline or polygonal type ("classical") of karst with numerous dolines (up to 57/km2) covered with terra rossa (red soil) and Mediterranean maquis shrubland. Dolines are located in zones which correspond to the strike of the main geological structures. Dry karstic valleys are visible only on gently inclined coastal slopes bordering the karstic plateau. In contrast, area B is typical of a bare karst landscape with a strong (palaeo)fluvial imprint. The dolines are absent, and the bedrock is only sporadically covered with terra rossa. Palaeogene marls have been observed in a few elongated depressions and in the coastal zone of area B. Along steep coastal slopes, valleys (up to 460 m/km2) are cut into the carbonates. The traces of episodic surface flows are visible in some of these valleys, in contrast to the valleys in area A. Remnants of a disrupted ancient fluvial network are clearly visible on the elevated karstic plateau in area B. Differences in the recent morphology are attributed mainly to varying thicknesses of the Palaeogene impermeable marly cover, and the intensity of tectonics in the two areas.

  9. Sinkhole susceptibility in carbonate rocks of the Apulian karst (southern Italy)

    Science.gov (United States)

    Di Santo, Antonio; Fazio, Nunzio L.; Fiore, Antonio; Lollino, Piernicola; Luisi, Michele; Miccoli, Maria N.; Pagliarulo, Rosa; Parise, Mario; Perrotti, Michele; Pisano, Luca; Spalluto, Luigi; Vennari, Carmela; Vessia, Giovanna

    2016-04-01

    Apulia region, the foreland of the southern Italian Apennines, is made up of a 6-7 km-thick succession of Mesozoic shallow-water limestones and dolostones, locally covered by thin and discontinuous Tertiary and Quaternary carbonate and clastic deposits. Due to their long subaerial exposure, the Mesozoic carbonate bedrock recorded the development in the subsurface of a dense network of karst cavities, mostly controlled by tectonic discontinuities. As a result, a strong susceptibility to natural sinkholes has to be recorded in Apulia. In addition, the possibility of occurrence of other problems related to the high number of man-made cavities has to be added in the region. A great variety of different typologies of artificial cavities (mostly excavated in the Plio-Pleistocene soft calcarenites) is actually present, including underground quarries, worship sites, oil mills, civilian settlements, etc. Overall, 2200 natural and 1200 artificial cavities, respectively, have been so far surveyed in Apulia. Following the urban development in the last century in Apulia, many of these cavities lie nowadays below densely populated neighborhoods, roads or communication routes. These conditions are at the origin of the main geomorphological hazard for the human society in Apulia, which requires a careful evaluation, aimed at protecting and safeguarding the human life, and at providing the necessary information for a correct land use planning and management. The importance of the sinkhole hazard is further testified by the worrying increase in the number of events during the last 5-6 years. In response to these situations, joint research activities were started by the Institute of Research for Hydrological Protection of the National Research Council (CNR-IRPI) and the Basin Authority of Apulia, aimed at several goals, that include (but are not limited to) the collection of information on natural and anthropogenic sinkholes in Apulia, the implementation of numerical analyses for

  10. Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy

    Directory of Open Access Journals (Sweden)

    P. De Vita

    2012-05-01

    Full Text Available Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation.

    In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy, coupled with the North Atlantic Oscillation (NAO.

    The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period.

    Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis.

    The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index.

    Although the effects of the North Atlantic Oscillation (NAO had already been demonstrated in the long-term precipitation and streamflow patterns of

  11. Assessing submarine groundwater discharge (SGD) and nitrate fluxes in highly heterogeneous coastal karst aquifers: Challenges and solutions

    Science.gov (United States)

    Montiel, Daniel; Dimova, Natasha; Andreo, Bartolomé; Prieto, Jorge; García-Orellana, Jordi; Rodellas, Valentí

    2018-02-01

    Groundwater discharge in coastal karst aquifers worldwide represents a substantial part of the water budget and is a main pathway for nutrient transport to the sea. Groundwater discharge to the sea manifests under different forms, making its assessment very challenging particularly in highly heterogeneous coastal systems karst systems. In this study, we present a methodology approach to identify and quantify four forms of groundwater discharge in a mixed lithology system in southern Spain (Maro-Cerro Gordo) that includes an ecologically protected coastal area comprised of karstic marble. We found that groundwater discharge to the sea occurs via: (1) groundwater-fed creeks, (2) coastal springs, (3) diffuse groundwater seepage through seabed sediments, and (4) submarine springs. We used a multi-method approach combining tracer techniques (salinity, 224Ra, and 222Rn) and direct measurements (seepage meters and flowmeters) to evaluate the discharge. Groundwater discharge via submarine springs was the most difficult to assess due to their depth (up to 15 m) and extensive development of the springs conduits. We determined that the total groundwater discharge over the 16 km of shoreline of the study area was at least 11 ± 3 × 103 m3 d-1 for the four types of discharge assessed. Groundwater-derived nitrate (NO3-) fluxes to coastal waters over ∼3 km (or 20%) in a highly populated and farmed section of Maro-Cerro Gordo was 641 ± 166 mol d-1, or ∼75% of the total NO3- loading in the study area. We demonstrate in this study that a multi-method approach must be applied to assess all forms of SGD and derived nutrient fluxes to the sea in highly heterogeneous karst aquifer systems.

  12. Hydrogeology of the cave Vetrovna jama in karst aquifer north from Planinsko polje (Notranjska region, central Slovenia

    Directory of Open Access Journals (Sweden)

    Franci Gabrovšek

    2009-06-01

    Full Text Available For one year we have been measuring level and temperature of underground water in Vetrovna jama, to find outthe origin of underground water and hydraulic characteristics of the cave and karst aquifer north east of Planinsko polje (karst of Notranjska region, central Slovenia. Similar parameters as in Vetrovna jama were measured also at the Unica River and at the Cerknica Lake. Cave is located only 2.7 km north from the polje and is fed by the Unica River, according to measurements. But in contrast with our expectations, we did not directly detect undergroundwater flow, which drains from the Cerknica Lake. Hydrographs measured in Vetrovna jama were compared with those measured in some other caves within the aquifer. Hydrographs from Vetrovna jama are only partly comparablewith hydrographs obtained in other monitored caves, as comparison shows no statistical significant correlation.Final conclusion would be that drainage of water between “eastern” and “western” part of karst aquifer islimited. More over, out flow from Vetrovna jama strongly depends on local hydrogeological restriction, such as supposedrockfall under Laška kukava collapse doline.

  13. Forming mechanism of the Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin

    Directory of Open Access Journals (Sweden)

    Heng Fu

    2017-07-01

    Full Text Available The Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin are important oil and gas exploration targets in the basin, but their dissolution mechanisms are in controversy. In this paper, based on the integrated study of sedimentation, sequence and reservoir, together with microscopic analysis and macroscopic seismic data analysis, the carbonate karst reservoirs in the study area were divided into three types: dissolved pore-cavity limestone reservoir, pore-cavity dolomite reservoir and fracture-cavity siliceous reservoir, and their forming mechanisms were discussed respectively. Some findings were obtained. First, dissolved pore-cavity limestone reservoirs are distributed in the upper Yingshan Fm and Yijianfang Fm of the Ordovician vertically, while pore-cavity dolomite reservoirs are mainly developed in the Penglai Fm and lower Yingshan Fm of the Ordovician with great thickness. Second, dissolved pore-cavity limestone reservoirs were formed by karstification on the third-order sequence boundary (lowstand tract, while pore-cavity dolomite reservoirs were formed by deep burial dolomitization controlled by karstification on the third-order sequence boundary, both of which are distributed in the highstand tract below the third-order sequence boundary. Third, siliceous reservoirs are developed under the control of faulting, as a result of reworking of deep hydrothermal fluids along faults to the limestone, and the siliceous reservoirs and their hydrothermal solution fracture-cavity systems are distributed near faults. It is further predicted that, in addition to the three types of reservoir above, platform-margin reef-flat reservoirs are developed in the Ordovician on the northern slope of central Tarim Basin.

  14. Bypassing and tightening of an underground water retention system in permeable karst: case study of the hydropower plant (HPP) Bribin, Indonesia

    Science.gov (United States)

    Kudella, Peter; Loges, Iryna; Mutschler, Thomas; Eiche, Elisabeth; Ruppert, Julia; Neumann, Thomas

    2016-09-01

    In the framework of the Integrated Water Resources Management (IWRM) joint research project in the karst area of Gunung Kidul, Province of Yogyakarta Special Region on the Java Island, Indonesia, an underground hydropower driven water extraction facility in the cave "Bribin" was developed using pump-as-turbine-driven systems for freshwater supply of the rural area. As numerous other caves in the Gunung Kidul area, Bribin is part of a ramified system of all-season water-bearing subterraneous rivers and natural caves in karstic limestone. The elliptic cross section of the cave was completely closed with a concrete barrage, thus creating a year-round underground retention volume with an operational storage level of approx. 15 m. This contribution highlights the geotechnical and geohydraulic challenges handled within the sub-project "Short-time and long-time behaviour of karst rock surrounding pressure-bearing underground water-retaining structures". One key to the feasibility of an artificial water retention scheme in a natural cave is to ensure the mechanical stability of the cave roof and sidewalls. The necessary geotechnical investigations are described. Another key to the effectiveness of such a water retention concept is the control and minimization of "lost" seepage water bypassing the barrage structure through the karst rock mass. Measures to monitor and to explain the seepage phenomena are presented as well as grouting efforts to minimize them. The limitations of improving the overall tightness will be discussed. Interpretation includes the use of analytical and numerical methods.

  15. Soil movements and surface erosion rates on rocky slopes in the mountain areas of the karst region of Southwest China

    Science.gov (United States)

    Zhang, X. B.; Bai, X. Y.; Long, Y.

    2012-04-01

    The karst region of Southwest China with an area of 54 × 104 km2 is one of the largest karst areas in the world and experiences subtropical climate. Hill-depressions are common landforms in the mountain areas of this region. Downslope soil movement on the ground by surface water erosion and soil sinking into underground holes by creeping or pipe erosion are mayor types of soil movements on rocky carbonate slopes. The 137Cs technique was used to date the sediment deposits in six karst depressions, to estimate average surface erosion rates on slopes from their catchments. The estimates of soil loss rates obtained from this study evidenced considerable variability. A value of 1.0 t km-2 year-1 was obtained for a catchment under original dense karst forest, but the erosion rates ranged between 19.3 t km-2 year-1 and 48.7 t km-2 year-1 in four catchments under secondary forest or grasses, where the original forest cover had been removed in the Ming and Qing dynasties, several hundred years ago. The highest rate of 1643 t km-2 year-1 was obtained for a catchment underlain by clayey carbonate rocks, where the soil cover was thicker and more extensive than in the other catchments and extensive land reclamation for cultivation had occurred during the period 1979-1981, immediately after the Cultural Revolution.

  16. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    Science.gov (United States)

    Musgrove, MaryLynn; Opsahl, Stephen P.; Mahler, Barbara J.; Herrington, Chris; Sample, Thomas; Banta, John

    2016-01-01

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3−) loading to surface and groundwater. We investigate variability and sources of NO3− in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008–12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3− stable isotopes (δ15N and δ18O). These data were augmented by historical data collected from 1937 to 2007. NO3− concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3− concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3− concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3−. These results highlight the vulnerability of karst aquifers to NO3− contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008–10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3−than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously

  17. Messinian Salinity Crisis' Primary Evaporites: the shallow gypsum vs. deep dolomite formation paradox solved

    Science.gov (United States)

    De Lange, G. J.; Krijgsman, W.

    2015-12-01

    The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, resulting in deposition of 1-3 km thick evaporites at the Mediterranean seafloor. A considerable, long-lasting controversy existed on the modes of their formation, including the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions at a precessional rhythm. Gypsum precipitation only occurred at marginal- and dolomite formation at deeper settings. A range of potential explanations was given, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are commonly neglected but may explain that different deposits formed in shallow vs deep environments without exceptional physical boundary conditions for each. A unifying mechanism is presented in which gypsum formation occurs at all shallow water depths but its preservation is limited to shallow sedimentary settings. In contrast, ongoing deep-basin anoxic organic matter (OM) degradation processes result in dolomite formation. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always oversaturated relative to dolomite but its formation is inhibited by the presence of dissolved sulphate. Thus conditions for formation of gypsum exclude those for formation of dolomite and vice versa. Another process linking the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, ongoing OM-degradation may result in reducing the sulphate and enhancing the dissolved carbonate content. Such low-sulphate / high carbonate conditions in MSC deepwater are. unfavorable for gypsum preservation and favorable for dolomite formation, and always coincide with anoxic, i.e. oxygen-free conditions. Including dynamic biogeochemical processes in the thusfar static

  18. Study of the factors affecting the karst volume assessment in the Dead Sea sinkhole problem using microgravity field analysis and 3-D modeling

    Directory of Open Access Journals (Sweden)

    L. V. Eppelbaum

    2008-11-01

    Full Text Available Thousands of sinkholes have appeared in the Dead Sea (DS coastal area in Israel and Jordan during two last decades. The sinkhole development is recently associated with the buried evaporation karst at the depth of 25–50 m from earth's surface caused by the drop of the DS level at the rate of 0.8–1.0 m/yr. Drop in the Dead Sea level has changed hydrogeological conditions in the subsurface and caused surface to collapse. The pre-existing cavern was detected using microgravity mapping in the Nahal Hever South site where seven sinkholes of 1–2 m diameter had been opened. About 5000 gravity stations were observed in the area of 200×200 m2 by the use of Scintrex CG-3M AutoGrav gravimeter. Besides the conventional set of corrections applied in microgravity investigations, a correction for a strong gravity horizontal gradient (DS Transform Zone negative gravity anomaly influence was inserted. As a result, residual gravity anomaly of –(0.08÷0.14 mGal was revealed. The gravity field analysis was supported by resistivity measurements. We applied the Emigma 7.8 gravity software to create the 3-D physical-geological models of the sinkholes development area. The modeling was confirmed by application of the GSFC program developed especially for 3-D combined gravity-magnetic modeling in complicated environments. Computed numerous gravity models verified an effective applicability of the microgravity technology for detection of karst cavities and estimation of their physical-geological parameters. A volume of the karst was approximately estimated as 35 000 m3. The visual analysis of large sinkhole clusters have been forming at the microgravity anomaly site, confirmed the results of microgravity mapping and 3-D modeling.

  19. The influence of conceptual model uncertainty on management decisions for a groundwater-dependent ecosystem in karst

    DEFF Research Database (Denmark)

    Gondwe, Bibi Ruth Neuman; Merediz-Alonso, Gonzalo; Bauer-Gottwein, Peter

    2011-01-01

    abstractions and pollution threatens the fresh water resource, and consequently the ecosystem integrity of both Sian Ka’an and the adjacent coastal environment. Seven different catchment-scale conceptual models were implemented in a distributed hydrological modelling approach. Equivalent porous medium...... to preserve water resources and maintain ecosystem services. Multiple Model Simulation highlights the impact of model structure uncertainty on management decisions using several plausible conceptual models. Multiple Model Simulation was used for this purpose on the Yucatan Peninsula, which is one of the world......Groundwater management in karst is often based on limited hydrologic understanding of the aquifer. The geologic heterogeneities controlling the water flow are often insufficiently mapped. As karst aquifers are very vulnerable to pollution, groundwater protection and land use management are crucial...

  20. Is Forest Restoration in the Southwest China Karst Promoted Mainly by Climate Change or Human-Induced Factors?

    Science.gov (United States)

    Cai, H.

    2017-12-01

    The Southwest China Karst, the largest continuous karst zone in the world, has suffered serious rock desertification due to the large population pressure in the area. Recent trend analyses have indicated general greening trends in this region. The region has experienced mild climate change, and yet significant land use changes, such as afforestation and reforestation. In addition, out-migration has occurred. Whether climate change or human-induced factors, i.e., ecological afforestation projects and out-migration have primarily promoted forest restoration in this region was investigated in this study, using Guizhou Province as the study area. Based on Moderate-Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data, we found general greening trends of the forest from 2000 to 2010. About 89% of the forests have experienced an increase in the annual NDVI, and among which, about 41% is statistically significant. For the summer season, more than 65% of the forests have increases in summer NDVI, and about 16% of the increases are significant. The strongest greening trends mainly occurred in the karst areas. Meanwhile, annual average and summer average temperature in this region have increased and the precipitation in most of the region has decreased, although most of these changes were not statistically significant (p > 0.1). A site-based regression analysis using 19 climate stations with minimum land use changes showed that a warming climate coupled with a decrease in precipitation explained some of the changes in the forest NDVI, but the results were not conclusive. The major changes were attributed to human-induced factors, especially in the karst areas. The implications of an ecological afforestation project and out-migration for forest restoration were also discussed, and the need for further investigations at the household level to better understand the out-migration-environment relationship was identified.

  1. Is Forest Restoration in the Southwest China Karst Promoted Mainly by Climate Change or Human-Induced Factors?

    Directory of Open Access Journals (Sweden)

    Hongyan Cai

    2014-10-01

    Full Text Available The Southwest China Karst, the largest continuous karst zone in the world, has suffered serious rock desertification due to the large population pressure in the area. Recent trend analyses have indicated general greening trends in this region. The region has experienced mild climate change, and yet significant land use changes, such as afforestation and reforestation. In addition, out-migration has occurred. Whether climate change or human-induced factors, i.e., ecological afforestation projects and out-migration have primarily promoted forest restoration in this region was investigated in this study, using Guizhou Province as the study area. Based on Moderate-Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI data, we found general greening trends of the forest from 2000 to 2010. About 89% of the forests have experienced an increase in the annual NDVI, and among which, about 41% is statistically significant. For the summer season, more than 65% of the forests have increases in summer NDVI, and about 16% of the increases are significant. The strongest greening trends mainly occurred in the karst areas. Meanwhile, annual average and summer average temperature in this region have increased and the precipitation in most of the region has decreased, although most of these changes were not statistically significant (p > 0.1. A site-based regression analysis using 19 climate stations with minimum land use changes showed that a warming climate coupled with a decrease in precipitation explained some of the changes in the forest NDVI, but the results were not conclusive. The major changes were attributed to human-induced factors, especially in the karst areas. The implications of an ecological afforestation project and out-migration for forest restoration were also discussed, and the need for further investigations at the household level to better understand the out-migration–environment relationship was identified.

  2. Volcanic sequence in Late Triassic – Jurassic siliciclastic and evaporitic rocks from Galeana, NE Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Gómez, E.M.; Velasco-Tapia, F.; Ramírez-Fernández, J.A.; Jenchen, U.; Rodríguez-Saavedra, P.; Rodríguez-Díaz, A.A.; Iriondo, A.

    2017-11-01

    In northeastern Mexico, volcanic rocks interbedded with Late Triassic–Jurassic siliciclastic and evaporitic strata have been linked to magmatic arcs developed in the Pangea western margin during its initial phase of fragmentation. This work provides new petrographic and geochemical data for volcanism included in the El Alamar and Minas Viejas formations outcropping in the Galeana region. Andesitic dykes and sills (n= 10) in the El Alamar redbeds show SiO2= 47.5–59.1% and MgO= 1.2–4.2%, as well as a geochemical affinity to island arc magmas. This work represents the first report of this tectonic setting in the region. Geological and petrographic evidence suggest that this arc system likely developed after ~220 and before ~193Ma. Trachy-andesitic and rhyodacitic domes (n= 20) associated with the Minas Viejas gypsum-carbonates sequence show SiO2= 61.8–82.7% and MgO= 0.1–4.0% with a tectonic affinity to continental arc. A rhyodacite sample from this region has been dated by U-Pb in zircon, yielding an age of 149.4 ± 1.2Ma (n= 21), being the youngest age related to this arc. Finally, we propose a threestep model to explain the tectonic evolution from Late Triassic island arc to Jurassic continental arc system in the northeastern Mexico.

  3. Volcanic sequence in Late Triassic – Jurassic siliciclastic and evaporitic rocks from Galeana, NE Mexico

    International Nuclear Information System (INIS)

    Cruz-Gómez, E.M.; Velasco-Tapia, F.; Ramírez-Fernández, J.A.; Jenchen, U.; Rodríguez-Saavedra, P.; Rodríguez-Díaz, A.A.; Iriondo, A.

    2017-01-01

    In northeastern Mexico, volcanic rocks interbedded with Late Triassic–Jurassic siliciclastic and evaporitic strata have been linked to magmatic arcs developed in the Pangea western margin during its initial phase of fragmentation. This work provides new petrographic and geochemical data for volcanism included in the El Alamar and Minas Viejas formations outcropping in the Galeana region. Andesitic dykes and sills (n= 10) in the El Alamar redbeds show SiO2= 47.5–59.1% and MgO= 1.2–4.2%, as well as a geochemical affinity to island arc magmas. This work represents the first report of this tectonic setting in the region. Geological and petrographic evidence suggest that this arc system likely developed after ~220 and before ~193Ma. Trachy-andesitic and rhyodacitic domes (n= 20) associated with the Minas Viejas gypsum-carbonates sequence show SiO2= 61.8–82.7% and MgO= 0.1–4.0% with a tectonic affinity to continental arc. A rhyodacite sample from this region has been dated by U-Pb in zircon, yielding an age of 149.4 ± 1.2Ma (n= 21), being the youngest age related to this arc. Finally, we propose a threestep model to explain the tectonic evolution from Late Triassic island arc to Jurassic continental arc system in the northeastern Mexico.

  4. Operational tools to help stakeholders to protect and alert municipalities facing uncertainties and changes in karst flash floods

    Science.gov (United States)

    Borrell Estupina, V.; Raynaud, F.; Bourgeois, N.; Kong-A-Siou, L.; Collet, L.; Haziza, E.; Servat, E.

    2015-06-01

    Flash floods are often responsible for many deaths and involve many material damages. Regarding Mediterranean karst aquifers, the complexity of connections, between surface and groundwater, as well as weather non-stationarity patterns, increase difficulties in understanding the basins behaviour and thus warning and protecting people. Furthermore, given the recent changes in land use and extreme rainfall events, knowledge of the past floods is no longer sufficient to manage flood risks. Therefore the worst realistic flood that could occur should be considered. Physical and processes-based hydrological models are considered among the best ways to forecast floods under diverse conditions. However, they rarely match with the stakeholders' needs. In fact, the forecasting services, the municipalities, and the civil security have difficulties in running and interpreting data-consuming models in real-time, above all if data are uncertain or non-existent. To face these social and technical difficulties and help stakeholders, this study develops two operational tools derived from these models. These tools aim at planning real-time decisions given little, changing, and uncertain information available, which are: (i) a hydrological graphical tool (abacus) to estimate flood peak discharge from the karst past state and the forecasted but uncertain intense rainfall; (ii) a GIS-based method (MARE) to estimate the potential flooded pathways and areas, accounting for runoff and karst contributions and considering land use changes. Then, outputs of these tools are confronted to past and recent floods and municipalities observations, and the impacts of uncertainties and changes on planning decisions are discussed. The use of these tools on the recent 2014 events demonstrated their reliability and interest for stakeholders. This study was realized on French Mediterranean basins, in close collaboration with the Flood Forecasting Services (SPC Med-Ouest, SCHAPI, municipalities).

  5. Challenges of using electrical resistivity method to locate karst conduits-A field case in the Inner Bluegrass Region, Kentucky

    Science.gov (United States)

    Zhu, J.; Currens, J.C.; Dinger, J.S.

    2011-01-01

    Conduits serve as major pathways for groundwater flow in karst aquifers. Locating them from the surface, however, is one of the most challenging tasks in karst research. Geophysical methods are often deployed to help locate voids by mapping variations of physical properties of the subsurface. Conduits can cause significant contrasts of some physical properties that can be detected; other subsurface features such as water-bearing fractures often yield similar contrasts, which are difficult to distinguish from the effects of the conduits. This study used electrical resistivity method to search for an unmapped karst conduit that recharges Royal Spring in the Inner Bluegrass karst region, Kentucky, USA. Three types of resistivity techniques (surface 2D survey, quasi-3D survey, and time-lapse survey) were used to map and characterize resistivity anomalies. Some of the major anomalies were selected as drilling targets to verify the existence of the conduits. Drilling near an anomaly identified by an electrical resistivity profile resulted in successful penetration of a major water-filled conduit. The drilling results also suggest that, in this study area, low resistivity anomalies in general are associated with water-bearing features. However, differences in the anomaly signals between the water-filled conduit and other water-bearing features such as water-filled fracture zones were undistinguishable. The electrical resistivity method is useful in conduit detection by providing potential drilling targets. Knowledge of geology and hydrogeology about the site and professional judgment also played important roles in locating the major conduit. ?? 2011 Elsevier B.V.

  6. Vertical distribution of bacteria and intensity of microbiological processes in two stratified gypsum Karst Lakes in Lithuania

    Directory of Open Access Journals (Sweden)

    Krevs A.

    2011-08-01

    Full Text Available Physical-chemical parameters and the vertical distribution of bacteria and organic matter production-destruction processes were studied during midsummer stratification in two karst lakes (Kirkilai and Ramunelis located in northern Lithuania. The lakes were characterized by high sulfate concentrations (369–1248 mg·L-1. The O2/H2S intersection zone formed at 2–3 m depth. In Lake Kirkilai, the highest bacterial densities (up to 8.7 × 106 cell·mL-1 occurred at the O2/H2S intersection zone, whereas in Lake Ramunelis the highest densities were observed in the anoxic hypolimnion (up to 11 × 106 cell·mL-1. Pigment analysis revealed that green sulfur bacteria dominated in the microaerobic–anaerobic water layers in both lakes. The most intensive development of sulfate-reducing bacteria was observed in the anaerobic layer. Photosynthetic production of organic matter was highest in the upper layer. Rates of sulfate reduction reached 0.23 mg S2−·dm3·d-1 in the microaerobic-anaerobic water layer and 1.97 mg S2−·dm3·d-1 in sediments. Karst lakes are very sensitive to organic pollution, because under such impact in the presence of high sulfate amounts, sulfate reduction may become very intensive and, consequently, the increase in hydrogen sulfide and development of sulfur cycle bacteria may reduce the variety of other hydrobionts.

  7. USGS geologic Mapping and karst research in the Ozark National Scenic Riverways, Missouri, USA

    Science.gov (United States)

    Weary, David J.; Grant, Victoria M

    2014-01-01

    The Ozark National Scenic Riverways (ONSR) was created in 1964 to protect 134 miles of the Current River and its major tributary, the Jacks Fork, that are located in south-central Missouri (fig. 1). The park includes numerous large karst springs including Big Spring, by flow volume this is the largest spring in the National Park system. The National Park Service (NPS) administers a narrow, nearly continuous corridor of land adjacent to the two rivers. Base flow for the rivers is chiefly supplied by groundwater that has traveled through the karst landscape from as far as 38 miles away from the spring (Imes and Frederick, 2002). The watershed is vulnerable to pollution, but the area remains largely rural with few industries. The springs and rivers provide habitat for numerous aquatic species as well as recreational resources for floaters, fishermen, and campers. The ONSR is a major cave park with hundreds of known caves and diverse in-cave resources.

  8. Numerical study of groundwater flow cycling controlled by seawater/freshwater interaction in a coastal karst aquifer through conduit network using CFPv2

    Science.gov (United States)

    Xu, Zexuan; Hu, Bill X.; Davis, Hal; Kish, Stephen

    2015-11-01

    In this study, a groundwater flow cycling in a karst springshed and an interaction between two springs, Spring Creek Springs and Wakulla Springs, through a subground conduit network are numerically simulated using CFPv2, the latest research version of MODFLOW-CFP (Conduit Flow Process). The Spring Creek Springs and Wakulla Springs, located in a marine estuary and 11 miles inland, respectively, are two major groundwater discharge spots in the Woodville Karst Plain (WKP), North Florida, USA. A three-phase conceptual model of groundwater flow cycling between the two springs and surface water recharge from a major surface creek (Lost Creek) was proposed in various rainfall conditions. A high permeable subground karst conduit network connecting the two springs was found by tracer tests and cave diving. Flow rate of discharge, salinity, sea level and tide height at Spring Creek Springs could significantly affect groundwater discharge and water stage at Wakulla Springs simultaneously. Based on the conceptual model, a numerical hybrid discrete-continuum groundwater flow model is developed using CFPv2 and calibrated by field measurements. Non-laminar flows in conduits and flow exchange between conduits and porous medium are implemented in the hybrid coupling numerical model. Time-variable salinity and equivalent freshwater head boundary conditions at the submarine spring as well as changing recharges have significant impacts on seawater/freshwater interaction and springs' discharges. The developed numerical model is used to simulate the dynamic hydrological process and quantitatively represent the three-phase conceptual model from June 2007 to June 2010. Simulated results of two springs' discharges match reasonably well to measurements with correlation coefficients 0.891 and 0.866 at Spring Creeks Springs and Wakulla Springs, respectively. The impacts of sea level rise on regional groundwater flow field and relationship between the inland springs and submarine springs are

  9. Ecological Stoichiometric Characteristics of Two Typical Plantations in the Karst Ecosystem of Southwestern China

    Directory of Open Access Journals (Sweden)

    Danbo Pang

    2018-01-01

    Full Text Available Reforestation has been widely adopted to restore soil fertility and ecosystem service function in the rocky desertification region of southwestern China. However, there has been limited research concerning the stoichiometry of carbon (C, nitrogen (N, and phosphorus (P and nutrient resorption rate of plantations in karst ecosystems. In this study, we selected plantations of Pinus yunnanensis Franch. (PY and Eucalyptus maideni F. Muell. (EM in Yunnan Province. The C, N, and P concentrations and the C:N:P stoichiometry in different soil layers (0–10 cm, 10–20 cm, and 20–30 cm were examined. The nutrient limitation and nutrient resorption efficiency were also analyzed. The leaf C and N concentrations in the PY plantation were higher than that in the EM plantation; the P concentration demonstrated the opposite trend, both in green and senesced leaves. Soil C, N, and P concentrations in the EM plantation were much greater than in the PY plantation at all three depths and decreased with the depth of the soil. In addition, the high ratios of C:P, N:P, C:Available P, and N:Available P in soil coupled with the ratios of N:P in leaves indicate that the EM plantation has a greater P deficiency than the PY plantation. In the EM plantation, the relatively low P concentrations in senesced leaves indicates efficient TP (Total phosphorus resorption, which highlights that the high reuse proficiency of P could have favored moderating P limitation in the karst ecosystem. This research aids in understanding the stoichiometric characteristics that mediate forest properties, and provides a basis for management of vegetation in karst ecosystems.

  10. The mammalian fauna of Barová Cave (Moravian Karst, the Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Roblíčková, M.; Káňa, V.; Nývltová Fišáková, Miriam

    2017-01-01

    Roč. 73, 3-4 (2017), s. 515-532 ISSN 2533-4050 Institutional support: RVO:68081758 Keywords : Quaternary palaeontology * Late Pleistocene * Moravian Karst * Barová Cave * animal assemblage * Ursus ex gr. spelaeus * wintering site * gnawing marks * hunting and scavenging * seasonality * dental age Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology http://fi.nm.cz/wp-content/uploads/2017/12/15_Roblickova_et-al_2017.pdf

  11. Strategy for investigation of fluid migration in evaporites (Waste Isolation Pilot Plant - WIPP)

    International Nuclear Information System (INIS)

    Lambert, S.J.; Shefelbine, H.C.

    1980-03-01

    The proposed strategy for WIPP project investigations of fluid migration in evaporites focuses upon a quantitative evaluation of each of several processes. Potential short- and long-term problems arising from fluid migration are complication of waste retrieval and mobilization of waste nuclides. The strategy will attempt to determine the degree to which these potentials are realized with respect to five hypothetical types of waste-rock interactions: movement of waste containers, migration of nuclides, formation of radioactive brine pocket, radiolytic generation of gas, and degradation of waste container. Of eight identified processes whose combinations could lead to the five types of interactions, only five are to be quantitatively investigated by the studies of fluid migration per se: presence of fluids, fluid mobilization toward heat-producing and contact-handled waste, encounter of fluids with influence of waste form, reversal of direction of fluid mobilization, and entrainment of nuclides in fluids. Methods of investigation entail an iterative combination of laboratory experimentation and mathematical modeling

  12. Investigation of Submarine Groundwater Discharge and Preferential Groundwater Flow-paths in a Coastal Karst Area using towed Marine and Terrestrial Electrical Resistivity

    Science.gov (United States)

    O'connell, Y.; Daly, E.; Duffy, G.; Henry, T.

    2012-12-01

    Large volumes of groundwater, containing nutrients and contaminants enter the coastal waters of southern Galway Bay on the west coast of Ireland through submarine groundwater discharge (SGD). The SGD occurs through karstified Carboniferous limestone in a major karst region comprising the Burren and Gort Lowlands. The Carboniferous limestones have experienced extensive dissolution resulting in the development of an underground network of conduits and fissures that define a trimodal groundwater flow pattern across the region. Groundwater discharge to the sea in this area is exclusively intertidal and submarine. Storage in the karst is limited and typical winter rainfall conditions result in the karst system becoming saturated. Temporary lakes (turloughs) form in lowlying areas and act as large reservoirs which provide storage to enable the transmission of the large volumes of water in the system to the sea. Between 2010 and 2012, terrestrial and shallow marine geophysical surveying has been undertaken to investigate preferential groundwater flow-paths and SGD locations in order to quantify the groundwater-seawater interactions in this coastal karst system. A report into the groundwater system of this karst region following a major flood event proposed a conceptual conduit model defined by extensive water tracing, water level monitoring, hydrochemical sampling, geological mapping and drilling. Limited information about the dimensions of the conduits was known. Electrical resistivity tomography (ERT) profiling to depths of 100m below ground level, with multiple array configurations, has been carried out to investigate the modes of groundwater flow in to and out of both temporary and permanent freshwater lakes in the system. Towed dipole-dipole profiles have been recorded to investigate conduits beneath a permanent lake exhibiting a tidal influence despite its location 5.5 km from the seashore. The ERT data indicates significant variations in subsurface resistivities

  13. Hydrological response and thermal effect of karst springs linked to aquifer geometry and recharge processes

    Science.gov (United States)

    Luo, Mingming; Chen, Zhihua; Zhou, Hong; Zhang, Liang; Han, Zhaofeng

    2018-03-01

    To be better understand the hydrological and thermal behavior of karst systems in South China, seasonal variations in flow, hydrochemistry and stable isotope ratios of five karst springs were used to delineate flow paths and recharge processes, and to interpret their thermal response. Isotopic data suggest that mean recharge elevations are 200-820 m above spring outlets. Springs that originate from high elevations have lower NO3 - concentrations than those originating from lower areas that have more agricultural activity. Measured Sr2+ concentrations reflect the strontium contents of the host carbonate aquifer and help delineate the spring catchment's saturated zone. Seasonal variations of NO3 - and Sr2+ concentrations are inversely correlated, because the former correlates with event water and the latter with baseflow. The mean annual water temperatures of springs were only slightly lower than the local mean annual surface temperature at the outlet elevations. These mean spring temperatures suggest a vertical gradient of 6 °C/vertical km, which resembles the adiabatic lapse rate of the Earth's stable atmosphere. Seasonal temperature variations in the springs are in phase with surface air temperatures, except for Heilongquan (HLQ) spring. Event-scale variations of thermal response are dramatically controlled by the circulation depth of karst systems, which determines the effectiveness of heat exchange. HLQ spring undergoes the deepest circulation depth of 820 m, and its thermal responses are determined by the thermally effective regulation processes at higher elevations and the mixing processes associated with thermally ineffective responses at lower elevations.

  14. Reply to Discussion by Zekai Șen on "Modeling karst spring hydrograph recession based on head drop at sinkholes"

    Science.gov (United States)

    Field, Malcolm S.; Goldscheider, Nico; Li, Guangquan

    2018-02-01

    We are pleased to learn that the model presented in our paper dealing with the "modeling karst spring hydrograph recession based on head drop at sinkholes," published in the Journal of Hydrology in 2016 (Li et al., 2016), is of interest to readers of this journal. Our study presented a new non-exponential model for assessing spring hydrographs in terms of head drop at flooded sinkholes, as an extension of an earlier model proposed by Li and Field (2014). In both papers, we used two spring hydrographs measured in the St. Marks Karst Watershed in northwest Florida to test the applicability and to verify the validity of our models.

  15. Going Underground: A Field Investigation and Lab Activity on Karst Topography and Water Systems

    Science.gov (United States)

    O'Dell, Gary; Gonzalez-Espada, Wilson

    2011-01-01

    Students learn science best with activities that mirror the way scientists work. This article describes how geologists investigate groundwater flow systems in areas of karst topography--geologic formations shaped by dissolving bedrock--and provides a way for students to replicate this research. Students also use electric current to model water…

  16. Image analyses in bauxitic ores: The case of the Apulian karst bauxites

    Science.gov (United States)

    Buccione, Roberto; Sinisi, Rosa; Mongelli, Giovanni

    2015-04-01

    This study concern two different karst bauxite deposits of the Apulia region (southern Italy). These deposits outcrop in the Murge and Salento areas: the Murge bauxite (upper Cretaceous) is a typical canyon-like deposit formed in a karst depression whereas the Salento bauxite (upper Eocene - Oligocene) is the result of the erosion, remobilization and transport of older bauxitic material from a relative distant area. This particular bauxite arrangement gave the name to all the same bauxite deposits which are thus called Salento-type deposits. Bauxite's texture is essentially made of sub-circular concentric aggregates, called ooids, dispersed in a pelitic matrix. The textural properties of the two bauxitic ores, as assessed by SEM-EDX, are different. In the bauxite from the canyon-like deposit the ooids/matrix ratio is higher than in the Salento-type bauxite. Furthermore the ooids in the Salento-like bauxite are usually made by a large core surrounded by a narrow, single, accretion layer, whereas the ooids from the canyon-like deposit have a smaller core surrounded by several alternating layers of Al-hematite and boehmite (Mongelli et al., 2014). In order to explore in more detail the textural features of both bauxite deposits, particle shape analyses were performed. Image analyses and the fractal dimension have been widely used in geological studies including economic geology (e.g. Turcotte, 1986; Meakin, 1991; Deng et al., 2011). The geometric properties evaluated are amounts of ooids, average ooids size, ooids rounding and the fractal dimension D, which depends on the ooids/matrix ratio. D is the slope of a plotting line obtained using a particular counting technique on each sample image. The fractal dimension is slightly lower for the Salento-type bauxites. Since the process which led to the formation of the ooids is related to an aggregation growth involving chemical fractionation (Mongelli, 2002) a correlation among these parameters and the contents of major

  17. Evaluation of Water Resource Security Based on an MIV-BP Model in a Karst Area

    Directory of Open Access Journals (Sweden)

    Liying Liu

    2018-06-01

    Full Text Available Evaluation of water resource security deserves particular attention in water resource planning and management. A typical karst area in Guizhou Province, China, was used as the research area in this paper. First, based on data from Guizhou Province for the past 10 years, the mean impact value–back propagation (MIV-BP model was used to analyze the factors influencing water resource security in the karst area. Second, 18 indices involving five aspects, water environment subsystem, social subsystem, economic subsystem, ecological subsystem, and human subsystem, were selected to establish an evaluation index of water resource security. Finally, a BP artificial neural network model was constructed to evaluate the water resource security of Guizhou Province from 2005 to 2014. The results show that water resource security in Guizhou, which was at a moderate warning level from 2005 to 2009 and a critical safety level from 2010 to 2014, has generally improved. Groundwater supply ratio, industrial water utilization rate, water use efficiency, per capita grain production, and water yield modulus were the obstacles to water resource security. Driving factors were comprehensive utilization rate of industrial solid waste, qualifying rate of industrial wastewater, above moderate rocky desertification area ratio, water requirement per unit gross domestic product (GDP, and degree of development and utilization of groundwater. Our results provide useful suggestions on the management of water resource security in Guizhou Province and a valuable reference for water resource research.

  18. U-isotopes and "2"2"6Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas

    International Nuclear Information System (INIS)

    Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

    2016-01-01

    Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ("2"3"8U, "2"3"5U and "2"3"4U) and "2"2"6Ra by alpha spectrometry were determined. The activity concentration of "2"3"8U presented a large variation from around 1.1 to 65 mBq L"−"1. Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The "2"3"4U/"2"3"8U activity ratios were higher than unity for all samples (1.1–3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. "2"2"6Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10"2 mBq L"−"1); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed "2"2"6Ra/"2"3"4U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). "2"2"6Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest "2"3"4U/"2"3"8U activity ratios, probably due to fast uniform bulk

  19. Thermophilic prokaryotic communities inhabiting the biofilm and well water of a thermal karst system located in Budapest (Hungary).

    Science.gov (United States)

    Anda, Dóra; Makk, Judit; Krett, Gergely; Jurecska, Laura; Márialigeti, Károly; Mádl-Szőnyi, Judit; Borsodi, Andrea K

    2015-07-01

    In this study, scanning electron microscopy (SEM) and 16S rRNA gene-based phylogenetic approach were applied to reveal the morphological structure and genetic diversity of thermophilic prokaryotic communities of a thermal karst well located in Budapest (Hungary). Bacterial and archaeal diversity of the well water (73.7 °C) and the biofilm developed on the inner surface of an outflow pipeline of the well were studied by molecular cloning method. According to the SEM images calcium carbonate minerals serve as a surface for colonization of bacterial aggregates. The vast majority of the bacterial and archaeal clones showed the highest sequence similarities to chemolithoautotrophic species. The bacterial clone libraries were dominated by sulfur oxidizer Thiobacillus (Betaproteobacteria) in the water and Sulfurihydrogenibium (Aquificae) in the biofilm. A relatively high proportion of molecular clones represented genera Thermus and Bellilinea in the biofilm library. The most abundant phylotypes both in water and biofilm archaeal clone libraries were closely related to thermophilic ammonia oxidizer Nitrosocaldus and Nitrososphaera but phylotypes belonging to methanogens were also detected. The results show that in addition to the bacterial sulfur and hydrogen oxidation, mainly archaeal ammonia oxidation may play a decisive role in the studied thermal karst system.

  20. A quantitative comparison of moldic and vuggy porosity structure in karst aquifers using image and geospatial analysis

    Science.gov (United States)

    Culpepper, A. R.; Manda, A. K.

    2011-12-01

    Limestone aquifers are vital sources of groundwater for domestic and industrial use throughout the world. To sustain rising population throughout the southeastern United States, aquifers are increasingly exploited to provide the populace clean and reliable water resources. The moldic Castle Hayne and the vuggy Biscayne aquifer systems are two highly productive aquifers that provide critical water resources to millions of citizens in eastern North Carolina and southeastern Florida, respectively. In order to better understand karst aquifers and evaluate the potential for contaminant transport, detailed investigation of 2D porosity and pore geometry using image and geospatial analysis were undertaken. The objective of this study is to compare and contrast the porosity structure of moldic and vuggy karst aquifers by quantifying 2D porosity and pore geometry from images of slabbed core samples and optical televiewer images. Televiewer images and images of painted core samples from the Spring Garden Member of the Castle Hayne aquifer and Miami Limestone Formation of the Biscayne aquifer were acquired for analysis of porosity structure. The procedure for converting images of slabbed core and televiewer images to a GIS useable format consisted of rectification, calibration, image enhancement, classification, recoding and filtering. In GIS, raster or vector formats were used to assess pore attributes (e.g., area and perimeter) and structure. Preliminary results show that both pore area and perimeter for the Spring Garden Member of the Castle Hayne and Miami Limestone Formation of the Biscayne aquifers can be described by exponential distributions. In both sets of slabbed core images the relatively small pores have the highest occurrence, whereas larger pores occur less frequently. However, the moldic Spring Garden Member of the Castle Hayne aquifer has larger pore sizes derived from cores images than the vuggy Miami Limestone Formation of Biscayne aquifer. Total porosity

  1. [Relationships between soil and rocky desertification in typical karst mountain area based on redundancy analysis].

    Science.gov (United States)

    Long, Jian; Liao, Hong-Kai; Li, Juan; Chen, Cai-Yun

    2012-06-01

    Redundancy analysis (RDA) was employed to reveal the relationships between soil and rocky desertification through vegetation investigation and analysis of soil samples collected in typical karst mountain area of southwest Guizhou Province. The results showed that except TP, TK and ACa, all other variables including SOC, TN, MBC, ROC, DOC, available nutrients and basal respiration showed significant downward trends during the rocky desertification process. RDA results showed significant correlations between different types of desertification and soil variables, described as non-degraded > potential desertification > light desertification > moderate desertification > severe desertification. Moreover, RDA showed that using SOC, TN, AN, and BD as soil indicators, 74.4% of the variance information on soil and rocky desertification could be explained. Furthermore, the results of correlation analysis showed that soil variables were significantly affected by surface vegetation. Considering the ecological function of the aboveground vegetation and the soil quality, Zanthoxylum would be a good choice for restoration of local vegetation in karst mountain area.

  2. Visualization of conduit-matrix conductivity differences in a karst aquifer using time-lapse electrical resistivity

    Science.gov (United States)

    Meyerhoff, Steven B.; Karaoulis, Marios; Fiebig, Florian; Maxwell, Reed M.; Revil, André; Martin, Jonathan B.; Graham, Wendy D.

    2012-12-01

    In the karstic upper Floridan aquifer, surface water flows into conduits of the groundwater system and may exchange with water in the aquifer matrix. This exchange has been hypothesized to occur based on differences in discharge at the Santa Fe River Sink-Rise system, north central Florida, but has yet to be visualized using any geophysical techniques. Using electrical resistivity tomography, we conducted a time-lapse study at two locations with mapped conduits connecting the Santa Fe River Sink to the Santa Fe River Rise to study changes of electrical conductivity during times of varying discharge over a six-week period. Our results show conductivity differences between matrix, conduit changes in resistivity occurring through time at the locations of mapped karst conduits, and changes in electrical conductivity during rainfall infiltration. These observations provide insight into time scales and matrix conduit conductivity differences, illustrating how surface water flow recharged to conduits may flow in a groundwater system in a karst aquifer.

  3. Analysis of methods to estimate spring flows in a karst aquifer.

    Science.gov (United States)

    Sepúlveda, Nicasio

    2009-01-01

    Hydraulically and statistically based methods were analyzed to identify the most reliable method to predict spring flows in a karst aquifer. Measured water levels at nearby observation wells, measured spring pool altitudes, and the distance between observation wells and the spring pool were the parameters used to match measured spring flows. Measured spring flows at six Upper Floridan aquifer springs in central Florida were used to assess the reliability of these methods to predict spring flows. Hydraulically based methods involved the application of the Theis, Hantush-Jacob, and Darcy-Weisbach equations, whereas the statistically based methods were the multiple linear regressions and the technology of artificial neural networks (ANNs). Root mean square errors between measured and predicted spring flows using the Darcy-Weisbach method ranged between 5% and 15% of the measured flows, lower than the 7% to 27% range for the Theis or Hantush-Jacob methods. Flows at all springs were estimated to be turbulent based on the Reynolds number derived from the Darcy-Weisbach equation for conduit flow. The multiple linear regression and the Darcy-Weisbach methods had similar spring flow prediction capabilities. The ANNs provided the lowest residuals between measured and predicted spring flows, ranging from 1.6% to 5.3% of the measured flows. The model prediction efficiency criteria also indicated that the ANNs were the most accurate method predicting spring flows in a karst aquifer.

  4. La Balouta exhumed karst: a Roman gold-mine-derived landscape within the Las Médulas UNESCO World Heritage Site (Spain

    Directory of Open Access Journals (Sweden)

    José M. Redondo-Vega

    2015-09-01

    Full Text Available The La Balouta Valley, located in the extreme SW region of the Las Médulas Natural Monument and UNESCO World Heritage Site (León, Spain, is one of the largest gold-mining sites developed by the Romans more than 2,000 years ago when excavating a thick series of red Miocene sediments in the area. The main determining feature of the La Balouta Valley, especially if we compare it with the Sil River Valley of which it is a tributary, is its status of a non-functional valley. It is a dry paleo-valley with a flat bottom and is characterized by limited surface water runoff and the presence of small cavities, channels, and residual karst topography. Variscan structures that form the structural framework of the study area underwent long-term erosion and supported deep sediment accumulation in the area during the Miocene, reaching depths of more than 100 m. A portion of these sediments accumulated over a karst, as indicated by karst channels that exhibit total and locally partial filling with red sediments similar to those mined at Las Médulas roughly 2 km further to the east. The presence of gold particles in one of the sediment samples and the identification of several characteristics common of formations mined by the Romans lead us to deem the La Balouta Valley an ancient paleokarst that was initially fossilized by deposition of red Miocene sediments and subsequently excavated via historical mining activities, which formed its current characteristics. In La Balouta, natural and anthropogenic processes have produced a unique cultural landscape that is reflective of systematic gold mining of sediments on the NW Iberian Peninsula by the Romans.

  5. [Relationships between landscape structure and rocky desertification in karst region of northwestern Guangxi].

    Science.gov (United States)

    Zhang, Xiao-nan; Wang, Ke-lin; Chen, Hong-song; Zhang, Wei

    2008-11-01

    By using canonical correspondence analysis (CCA), sixteen landscape indices were adopted to quantitatively analyze the relationships between the landscape structure and rocky desertification in karst region of Huanjiang County, Guangxi Province. The results showed that the first and the second ordination axis of CCA were strongly correlated to the factors of average patch area, average dry land patch area, landscape shape index, and landscape aggregation index. The potential rocky desertification in the region was highly positively correlated with the average dry land patch area and the average fractal dimensions of dry land and shrub land, but negatively correlated with the patch numbers of dry land. Light rocky desertification had obvious positive correlations with the fractal dimension index, average fractal dimension of unused land, and patch numbers of shrub land; while moderate and strong rocky desertification had high positive correlations with the average unused land patch area but negative correlation with the average fractal dimension of shrub land. To some extent, rocky desertification degree might be represented by the values of landscape indices. The gradient variation in karst rocky desertification along landscape structure was clearly presented by the results of CCA.

  6. Humus soil as a critical driver of flora conversion on karst rock outcrops.

    Science.gov (United States)

    Zhu, Xiai; Shen, Youxin; He, Beibei; Zhao, Zhimeng

    2017-10-03

    Rock outcrop is an important habitat supporting plant communities in karst landscape. However, information on the restoration of higher biotic populations on outcrops is limited. Here, we investigated the diversity, biomass changes of higher vascular plants (VP) and humus soil (HS) on karst outcrops during a restoration process. We surveyed VP on rock outcrops and measured HS reserved by various rock microhabitats in a rock desertification ecosystem (RDE), an anthropogenic forest ecosystem (AFE), and a secondary forest ecosystem (SFE) in Shilin County, southwest China. HS metrics (e.g. quantity and nutrients content) and VP metrics (e.g. richness, diversity and biomass) were higher at AFE than at RDE, but lower than at SFE, suggesting that the restoration of soil subsystem vegetation increased HS properties and favored the succession of VP on rock outcrops. There was significantly positive correlation between VP metrics and HS amount, indicating that the succession of VP was strongly affected by availability and heterogeneity of HS in various rock microhabitats. Thus, floral succession of rock subsystem was slow owing to the limited resources on outcrops, although the vegetation was restored in soil subsystem.

  7. Ethnogeological Cultural Model of Karst Derived from Traditional Knowledge in Puerto Rico and Dominican Republic

    Science.gov (United States)

    Garcia, A.; Semken, S. C.; Brandt, E.

    2017-12-01

    Ethnogeology is the scientific study of human relationships with and knowledge of the Earth system, and is typically investigated within the context of a specific culture. Many indigenous and local systems of environmental and place knowledge incorporate empirical observations and culturally framed interpretations of geological features and processes. Ethnogeological interpretations may differ from those of conventional mainstream geoscience, but they are validated by their direct relevance to long-term cultural and environmental resilience and sustainability, typically in challenging environments. Ethnogeologic findings can enrich geoscientific knowledge bases for further research, and inform place-based geoscience education that has been shown to engage and enrich students from diverse underrepresented minority backgrounds. Ethnogeological research blends methods from field geology with methods from field ethnography: such as participant observation, free listing, participatory mapping, and cultural consensus analysis among other methods from rapid participatory assessment. We report here on an ongoing field study in Puerto Rico (PR) and the Dominican Republic (DR) on ethnogeological knowledge of karst topography, geology, and hydrogeology among local cultural indigenous communities such as the Boricua jíbaro and the Dominican campesino. Applied focused ethnographic fieldwork results suggest a good fit for the cultural consensus model about geological processes among culturally expert consultants in DR (4.604) and PR (4.669), as well as competence average with values of 0.552 and 0.628 respectively. This suggests the existence of a regional cultural model for the domain of karst that is shared between PR and DR populations that reside in or near karst terrain. Additional data in support of the cultural model include stories, analogies, and family history using participant observation, and participatory mapping.

  8. Dating of speleothems in non-karst caves - methodological aspects and practical application, Polish Outer Carpathians case study

    Czech Academy of Sciences Publication Activity Database

    Urban, J.; Margielewski, W.; Hercman, H.; Žák, Karel; Zernitska, V.; Pawlak, J.; Schejbal-Chwastek, M.

    2015-01-01

    Roč. 59, Supplement 1 (2015), s. 185-210 ISSN 0372-8854 Institutional support: RVO:67985831 Keywords : non-karst caves * speleothem dating * landslide * Polish Outer Carpathians Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.103, year: 2015

  9. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas

    Energy Technology Data Exchange (ETDEWEB)

    Musgrove, M., E-mail: mmusgrov@usgs.gov [U.S. Geological Survey, 1505 Ferguson Lane, Austin, TX 78754 (United States); Opsahl, S.P. [U.S. Geological Survey, 5563 DeZavala, Ste. 290, San Antonio, TX 78249 (United States); Mahler, B.J. [U.S. Geological Survey, 1505 Ferguson Lane, Austin, TX 78754 (United States); Herrington, C. [City of Austin Watershed Protection Department, Austin, TX 78704 (United States); Sample, T.L. [U.S. Geological Survey, 19241 David Memorial Dr., Ste. 180, Conroe, TX 77385 (United States); Banta, J.R. [U.S. Geological Survey, 5563 DeZavala, Ste. 290, San Antonio, TX 78249 (United States)

    2016-10-15

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO{sub 3}{sup −}) loading to surface and groundwater. We investigate variability and sources of NO{sub 3}{sup −} in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008–12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO{sub 3}{sup −} stable isotopes (δ{sup 15}N and δ{sup 18}O). These data were augmented by historical data collected from 1937 to 2007. NO{sub 3}{sup −} concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO{sub 3}{sup −} concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO{sub 3}{sup −} concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO{sub 3}{sup −}. These results highlight the vulnerability of karst aquifers to NO{sub 3}{sup −} contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008–10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO{sub 3}{sup −} than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates

  10. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas

    International Nuclear Information System (INIS)

    Musgrove, M.; Opsahl, S.P.; Mahler, B.J.; Herrington, C.; Sample, T.L.; Banta, J.R.

    2016-01-01

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO 3 − ) loading to surface and groundwater. We investigate variability and sources of NO 3 − in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008–12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO 3 − stable isotopes (δ 15 N and δ 18 O). These data were augmented by historical data collected from 1937 to 2007. NO 3 − concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO 3 − concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO 3 − concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO 3 − . These results highlight the vulnerability of karst aquifers to NO 3 − contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008–10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO 3 − than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a

  11. Delineating groundwater/surface water interaction in a karst watershed: Lower Flint River Basin, southwestern Georgia, USA

    Directory of Open Access Journals (Sweden)

    Kathleen Rugel

    2016-03-01

    Full Text Available Study region: Karst watershed in Lower Flint River Basin (LFRB, southwestern Georgia, USA. Study focus: Baseflow discharges in the LFRB have declined for three decades as regional irrigation has increased; yet, the location and nature of connectivity between groundwater and surface water in this karstic region are poorly understood. Because growing water demands will likely be met by further development of regional aquifers, an important management concern is the nature of interactions between groundwater and surface water components under natural and anthropogenic perturbations. We conducted coarse and fine-scale stream sampling on a major tributary of the Lower Flint River (Ichawaynochaway Creek in southwestern Georgia, USA, to identify locations and patterns of enhanced hydrologic connectivity between this stream and the Upper Floridan Aquifer. New hydrological insights for the region: Prior water resource studies in the LFRB were based on regional modeling that neglected local heterogeneities in groundwater/surface water connectivity. Our results demonstrated groundwater inputs were concentrated around five of fifty sampled reaches, evidenced by increases in multiple groundwater indicators at these sites. These five reaches contributed up to 42% of the groundwater detected along the entire 50-km sampling section, with ∼24% entering through one groundwater-dominated tributary, Chickasawhatchee Creek. Intermittent flows occurred in two of these upstream reaches during extreme drought and heavy groundwater pumping, suggesting reach-scale behaviors should be considered in resource management and policy. Keywords: Karst hydrogeology, Hydrologic connectivity, Groundwater/surface water interaction, Upper Floridan Aquifer, Groundwater Irrigation

  12. Genotype-specific microsatellite (SSR) markers for the sugarcane germplasm in the Karst region of Guizhou, China

    Science.gov (United States)

    It is the first report on SSR-based molecular evaluation of genetic variability among sugarcane genotypes from the Karst region of China that provides useful information for local sugarcane improvement. Eighteen sugarcane genotypes including 13 active cultivars and five elite QT-series clones bred l...

  13. Existence of both culturable and viable but non culturable (VNC) E. coli populations with distinct settling velocities in karst aquifer

    Science.gov (United States)

    Petit, F.; Ratajczak, M.; Massei, N.; Lafite, R.; Clermont, O.; Denamur, E.; Berthe, T.

    2012-12-01

    The karst aquifers are particularly vulnerable to contamination by faecal pathogens mainly during rainfall event. In groundwater, the fate of E. coli is dependent on their ability to overcome environmental stresses and on their association with particles. Moreover, some strains can survive leading to the emergence of a sub-population of E. coli which failed to grow on laboratory media, while they were still alive thus designated as viable but non culturable (VNC). The aim of this study was to investigate (i) the structure of culturable E. coli population based on the survival ability, the distribution in four main phylo-groups (A, B1, B2, D) and the phenotypic characteristics; and, (ii) the fate of culturable and VNC E. coli, according to their settling velocities. This work was carried out on a karstic workshop-site for which the microbial quality of water was impaired related to livestock density and septic tanks overflows. Particles characterisation was performed by estimation of their settling velocities combined with electronic microscopy observation, and solid phase cytometry (ChemScan®RDI) was carried out to quantify the viable E. coli, and thus VNC E. coli. In the karst, different populations of E. coli were coexisting related to their survival, their culturability, and their association to particles. At the sinkhole, during a rainfall event with pasture, E. coli rapidly losing their culturability after 2 days have been more frequently isolated. These isolates are mainly multiresistant to antibiotics and harbor several virulence factors. In the same time, a population of VNC E. coli (79%), associated to the "non settleable particles" (settling velocities ranging between 10-5 to 10-2 mm.s-1), mainly corresponding to colloids and organic or organo-mineral microflocs was injected in the karst system, probably corresponding to the runoff of attached-bacteria originating from cowpats. Once in the karst, the relative contribution of culturable and VNC E. coli

  14. Hydrological controls on transient aquifer storage in a karst watershed

    Science.gov (United States)

    Spellman, P.; Martin, J.; Gulley, J. D.

    2017-12-01

    While surface storage of floodwaters is well-known to attenuate flood peaks, transient storage of floodwaters in aquifers is a less recognized mechanism of flood peak attenuation. The hydraulic gradient from aquifer to river controls the magnitude of transient aquifer storage and is ultimately a function of aquifer hydraulic conductivity, and effective porosity. Because bedrock and granular aquifers tend to have lower hydraulic conductivities and porosities, their ability to attenuate flood peaks is generally small. In karst aquifers, however, extensive cave systems create high hydraulic conductivities and porosities that create low antecedent hydraulic gradients between aquifers and rivers. Cave springs can reverse flow during high discharges in rivers, temporarily storing floodwaters in the aquifer thus reducing the magnitude of flood discharge downstream. To date however, very few studies have quantified the magnitude or controls of transient aquifer storage in karst watersheds. We therefore investigate controls on transient aquifer storage by using 10 years of river and groundwater data from the Suwannee River Basin, which flows over the karstic upper Floridan aquifer in north-central Florida. We use multiple linear regression to compare the effects of three hydrological controls on the magnitude of transient aquifer storage: antecedent stage, recharge and slope of hydrograph rise. We show the dominant control on transient aquifer storage is antecedent stage, whereby lower stages result in greater magnitudes of transient aquifer storage. Our results suggest that measures of groundwater levels prior to an event can be useful in determining whether transient aquifer storage will occur and may provide a useful metric for improving predictions of flood magnitudes.

  15. Using nitrate to quantify quick flow in a karst aquifer

    Science.gov (United States)

    Mahler, B.J.; Garner, B.D.

    2009-01-01

    In karst aquifers, contaminated recharge can degrade spring water quality, but quantifying the rapid recharge (quick flow) component of spring flow is challenging because of its temporal variability. Here, we investigate the use of nitrate in a two-endmember mixing model to quantify quick flow in Barton Springs, Austin, Texas. Historical nitrate data from recharging creeks and Barton Springs were evaluated to determine a representative nitrate concentration for the aquifer water endmember (1.5 mg/L) and the quick flow endmember (0.17 mg/L for nonstormflow conditions and 0.25 mg/L for stormflow conditions). Under nonstormflow conditions for 1990 to 2005, model results indicated that quick flow contributed from 0% to 55% of spring flow. The nitrate-based two-endmember model was applied to the response of Barton Springs to a storm and results compared to those produced using the same model with ??18O and specific conductance (SC) as tracers. Additionally, the mixing model was modified to allow endmember quick flow values to vary over time. Of the three tracers, nitrate appears to be the most advantageous because it is conservative and because the difference between the concentrations in the two endmembers is large relative to their variance. The ??18O- based model was very sensitive to variability within the quick flow endmember, and SC was not conservative over the timescale of the storm response. We conclude that a nitrate-based two-endmember mixing model might provide a useful approach for quantifying the temporally variable quick flow component of spring flow in some karst systems. ?? 2008 National Ground Water Association.

  16. Karst and Caves of the Black Hills, South Dakota, USA; Karst y cuevas de las Black Hills, Dakota del Sur, EE.UU

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A. N.

    2016-07-01

    The caves of the Black Hills are located in Carboniferous limestone and dolomite of the Madison Formation in western South Dakota. The climate is semi-arid, and surface karst features are few. Entrances to known caves are rather small, and the two largest caves, Wind Cave and Jewel Cave, were discovered only in the late 1880s and in 1900, respectively. Intermittent exploration and mapping have been conducted by local volunteers, National Park Service staff, and the National Speleological Society. Jewel Cave, in Jewel Cave National Monument, contains 290 km of mapped passages; and Wind Cave, in Wind Cave National Park, contains 230 km. They are the third and sixth longest known caves in the world. (Author)

  17. Spatial-temporal Evolution of Karst Rocky Desertification and Future Trends Based on CA-Markov Methods in Typical Karst Valley

    Directory of Open Access Journals (Sweden)

    CHEN Fei

    2018-02-01

    Full Text Available Karst rocky desertification(KRDhas become the most serious ecological disaster in Southwest China. It is very important and much-needed to explore the rule of spatial-temporal evolution of KRD for ecological restoration and sustainable development of the region. In this paper, the improved accurate remote sensing image interpreting method and CA-Markov prediction method were used to explore the spatial-temporal evolution rule of KRD in the study area from 1990 to 2021 based on the long time line remote sensing image of the year of 1990, 2004 and 2016. The results were as follows:the spatial -temporal evolution rule of KRD presented "first deterioration and then improvement" in the study area at nearly 30 years. The deterioration of KRD was affected by high intensity overload human activities and natural disasters in 1990-2004, which made the ecological environment deterioration. However, the KRD had gradually improved with the implementation of a series of governance projects, and a large number of rural labor forces were liberated from the land in 2004-2016, which made the natural environment restoration, and ecological system was getting better and better. At the same time, the trend of KRD evolution was showing improvement from the predicted years of 2016-2021 and the ecological environment in the region continued to become better.

  18. Heterogeneous flow in multi-layer joint networks and its influence on incipient karst generation

    Science.gov (United States)

    Wang, X.; Jourde, H.

    2017-12-01

    Various dissolution types (e.g. pipe, stripe and sheet karstic features) have been observed in fractured layered limestones. Yet, due to a large range of structural and hydraulic parameters play a role in the karstification process, the dissolution mechanism, occurring either along fractures or bedding planes, is difficult to quantify. In this study, we use numerical models to investigate the influence of these parameters on the generation of different types of incipient karst. Specifically, we focus on two parameters: the fracture intensity contrast between adjacent layers and the aperture ratio between bedding planes and joints (abed/ajoint). The DFN models were generated using a pseudo-genetic code that considers the stress shadow zone. Flow simulations were performed using a combined finite-volume finite-element simulator under practical boundary conditions. The flow channeling within the fracture networks was characterized by applying a multi-fractal technique. The rock block equivalent permeability (keff) was also calculated to quantify the change in bulk hydraulic properties when changing the selected structural and hydraulic parameters. The flow simulation results show that the abed/ajoint ratio has a first-order control on the heterogeneous distribution of flow in the multi-layer system and on the magnitude of equivalent permeability. When abed/ajoint 0.1, the bedding plane has more control and flow becomes more pervasive and uniform, and the keff is accordingly high. A simple model, accounting for the calculation of the heterogeneous distributions of Damköhler number associated with different aperture ratios, is proposed to predict what type of incipient karst tends to develop under the studied flow conditions.

  19. Evaporite-hosted native sulfur in Trans-Pecos Texas: Relation to late-phase basin and range deformation

    International Nuclear Information System (INIS)

    Hentz, T.F.; Henry, C.D.

    1989-01-01

    Major deposits of biogenic native sulfur are associated with narrow, northeast-trending grabens and normal faults that disrupt the gently tilted, east-dipping Upper Permian evaporite succession of the western Delaware Basin in Trans-Pecos Texas. Orebodies are restricted to geologic traps in the fractured and dissolution-modified downfaulted blocks of the grabens. Other parallel, regionally distributed grabens and normal faults are commonly the sites of noncommercial sulfur deposits and genetically related secondary-replacement (diagenetic) limestone bodies. The sulfur-bearing structures probably formed during the later of two episodes of Basin and Range extension that have not previously been differentiated in Texas but are well defined elsewhere in the western United States. In Texas several lines of evidence collectively support the existence of late-phase, northwest-directed extension that was initiated in the middle Miocene

  20. Water control at certain karst U-mining area

    International Nuclear Information System (INIS)

    Lei Mingxin; Xu Qiang

    2010-01-01

    To ensure mining security, water control for certain mining area is designed. Hydrogeological conditions in the studied area are analyzed. Four methods were used to calculate the inflow of water at mineral area, such as 'bigwell' method and 'groundwater isostatic' method according to the karst development. The calculated data for average inflow of water for the 100 m middle section are mainly compared with the data for the inflow of spring water in this deposit observed during the last five years. The difference between them is found minor. This indicates that the parameters selected for the calculation of inflow of water are reasonable and the methods used are suitable. Taking into account the above, it is decided to use the combination of surface water control and groundwater control Surface water control first,and groundwater control second, Five methods are used for surface water control such as plugging, filling, stopping, draining and dredging. Three methods for groundwater control such as curtain grouting, drainage in advance and blocking. The implimentation of this program will greatly reduce the threat of groundwater in ming area to mining operation and the cost of treatment of water discharge in mining pits and wells ,and effectively protect the environment and ensure the local people's living and production. (authors)

  1. Audio-magnetotelluric surveys to constrain the origin of a network of narrow synclines in Eocene limestone, Western Desert, Egypt

    Science.gov (United States)

    Tarabees, Elhamy A.; Tewksbury, Barbara J.; Mehrtens, Charlotte J.; Younis, Abdellatif

    2017-12-01

    Recent work with high resolution satellite imagery has revealed a network of narrow synclines developed during the Oligocene or Miocene over tens of thousands of square kilometers in Eocene limestone of the Thebes Group in the Western Desert of Egypt. The synclines are non-tectonic, and their scale and geometry strongly resemble sag synclines in Qatar that were produced by dissolution of subsurface evaporites and resulting sag of overlying layers. Evaporite dissolution cannot explain the Egypt synclines, because subsurface evaporites of any significance have never been reported in this part of Egypt. In this study, we use audio-magnetotelluric surveys to illuminate the subsurface under the synclines in order to constrain possible models for their formation. We suspected karst dissolution at depth, and, given a modern water table depth of over 400 m, we expected that dry fracture networks and void spaces under the synclines might result in higher electrical resistivities than surrounding coherent limestone. We also anticipated a significant change from high to low resistivity at the contact between the Thebes Group and the underlying Esna Shale at depths of 400 m or more. Instead, we found localized low resistivity zones extending from about 50-100 m below the surface to depths of more than 400 m that are strongly correlated with synclines. We suggest that these localized low resistivity zones are filled with artesian groundwater that has insufficient hydraulic head to rise to the modern topographic surface and that is localized in subsurface voids and collapse breccias produced by dissolution. Sag of overlying limestone layers is a reasonable model for syncline formation but, given the Oligocene/Miocene age of the synclines, dissolution and sag would be unrelated to young groundwater processes.

  2. Hydrogeology of salt karst under different cap soils and climates (Persian Gulf and Zagros Mts., Iran)

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Kamas, J.; Filippi, Michal; Zare, M.; Mayo, A. L.

    2017-01-01

    Roč. 46, č. 2 (2017), s. 303-320 ISSN 0392-6672 R&D Projects: GA AV ČR KJB315040801 Institutional support: RVO:67985831 Keywords : diapir * salt karst * soil * arid * chemistry * isotope Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.439, year: 2016

  3. Numerical study of groundwater flow cycling controlled by seawater/freshwater interaction in a coastal karst aquifer through conduit network using CFPv2.

    Science.gov (United States)

    Xu, Zexuan; Hu, Bill X; Davis, Hal; Kish, Stephen

    2015-11-01

    In this study, a groundwater flow cycling in a karst springshed and an interaction between two springs, Spring Creek Springs and Wakulla Springs, through a subground conduit network are numerically simulated using CFPv2, the latest research version of MODFLOW-CFP (Conduit Flow Process). The Spring Creek Springs and Wakulla Springs, located in a marine estuary and 11 miles inland, respectively, are two major groundwater discharge spots in the Woodville Karst Plain (WKP), North Florida, USA. A three-phase conceptual model of groundwater flow cycling between the two springs and surface water recharge from a major surface creek (Lost Creek) was proposed in various rainfall conditions. A high permeable subground karst conduit network connecting the two springs was found by tracer tests and cave diving. Flow rate of discharge, salinity, sea level and tide height at Spring Creek Springs could significantly affect groundwater discharge and water stage at Wakulla Springs simultaneously. Based on the conceptual model, a numerical hybrid discrete-continuum groundwater flow model is developed using CFPv2 and calibrated by field measurements. Non-laminar flows in conduits and flow exchange between conduits and porous medium are implemented in the hybrid coupling numerical model. Time-variable salinity and equivalent freshwater head boundary conditions at the submarine spring as well as changing recharges have significant impacts on seawater/freshwater interaction and springs' discharges. The developed numerical model is used to simulate the dynamic hydrological process and quantitatively represent the three-phase conceptual model from June 2007 to June 2010. Simulated results of two springs' discharges match reasonably well to measurements with correlation coefficients 0.891 and 0.866 at Spring Creeks Springs and Wakulla Springs, respectively. The impacts of sea level rise on regional groundwater flow field and relationship between the inland springs and submarine springs are

  4. Study of the hydrodynamic of groundwater karst system of Laraos and Alis, upper basin of the Canete river using environmental isotopes

    International Nuclear Information System (INIS)

    Valencia, Jacinto; Mamani, Enoc; Magina, Jose

    2014-01-01

    In this study, seven water samples have been characterized, collected from the upper Canete river micro-basins Laraos and Alis. They were analyzed by Oxygen-18 (δ18O), deuterium (δ2H) and radioactive tritium (3H) using the technique of laser spectrometry and characterized in order to establish the recharge-discharge relationship karst system under study, formed by the dissolution of limestone from the Cretaceous age formation Jumasha, and forming watertight groundwater that by connection and hydraulic gradient of fractures discharge into springs. The interpretation of the isotopic analysis performed according to the diagram δ18O/δ2H indicates that the springs are originated from infiltrating rainwater into the karst system due to the structural design and make the connection between micro-basins. Groundwater has a different dynamic, and to a lesser extent, receives contributions from waters lagoons, this fact makes them vulnerable to contamination. In the karst hydrogeological system, groundwater from micro-basins has a dynamic part of water with a long residence time with 1.8 units of tritium (RC-7) and another water dynamic of short residence time of 3 and 3.2 tritium units (RC-4, RC-5, RC-6). (authors).

  5. Microbial diversity in sediment ecosystems (evaporites domes, microbial mats and crusts of hypersaline Laguna Tebenquiche, Salar de Atacama, Chile

    Directory of Open Access Journals (Sweden)

    Ana Beatriz Fernandez

    2016-08-01

    Full Text Available We combined nucleic acid-based molecular methods, biogeochemical measurements and physicochemical characteristics to investigate microbial sedimentary ecosystems of Laguna Tebenquiche, Atacama Desert, Chile. Molecular diversity and biogeochemistry of hypersaline microbial mats, rhizome-associated concretions and an endoevaporite were compared with: The V4 hypervariable region of the 16S rRNA gene was amplified by pyrosequencing to analyze the total microbial diversity (i.e., bacteria and archaea in bulk samples and, in addition, in detail on a millimeter scale in one microbial mat and in one evaporite. Archaea were more abundant than bacteria. Euryarchaeota was one of the most abundant phyla in all samples, and particularly dominant (97% of total diversity in the most lithified ecosystem, the evaporite. Most of the euryarchaeal OTUs could be assigned to the class Halobacteria or anaerobic and methanogenic archaea. Planctomycetes potentially also play a key role in mats and rhizome-associated concretions, notably the aerobic organoheterotroph members of the class Phycisphaerae. In addition to cyanobacteria, members of Chromatiales and possibly the candidate family Chlorotrichaceae contributed to photosynthetic carbon fixation. Other abundant uncultured taxa such as the candidate division MSBL1, the uncultured MBGB and the phylum Acetothermia potentially play an important metabolic role in these ecosystems. Lithifying microbial mats contained calcium carbonate precipitates, whereas endoevoporites consisted of gypsum and halite. Biogeochemical measurements revealed that based on depth profiles of O2 and sulfide, metabolic activities were much higher in the non-lithifying mat (peaking in the least lithified systems than in lithifying mats with the lowest activity in endoevaporites. This trend in decreasing microbial activity reflects the increase in salinity, which may play an important role in the biodiversity.

  6. Study on Karst Rock Desertification by Human-Nature Interaction: A Case Study of Fengshan County of Guangxi, China

    Science.gov (United States)

    Zhou, G.; Su, C.; Zhang, R.; Shi, Y.; Liu, Y.; Ma, Y.

    2014-11-01

    Rocky desertification is a process of soil erosion leading to the bareness of bedrock, and is a kind of typical natural disaster in karst areas, which seriously constrains the developments of local society and economy. This paper studies the impact of human activities on the changes of rocky desertification. With the interpretation of remote sensing images of Fengshan County, GuangXi, China covering 1990, 1995 and 2005, this paper analyzes the relationship of the changes of social and economic index (including population density, agricultural population, rural per capital net income, and farmland) and the changes of rocky desertification in recent 15 years. The results indicate that: in recent 15 years, the average annual growth rate of rocky desertification, rate of change of population density, agricultural population, rural per capita net income, and farmland area are 8.7375 km2 /year, 0.7 person/km2.year, 1153 person/year, 85 Yuan/year, and -269.1 ha/year, respectively. The first three of social and economic indicators at different degrees of growth, show a positive correlation with rocky desertification change. However, farmland area, which has been diminishing, shows a negative correlation with rocky desertification. The influence of human activities for karst rocky desertification can be regarded as population growth - steep slope reclamation - the destruction of vegetation - erosion - rocky desertification - poverty.

  7. Biochemical mechanisms of resistance to p-nitrochlorobenzene of karst caves microorganisms

    Directory of Open Access Journals (Sweden)

    O. S. Suslova

    2015-08-01

    Full Text Available The biochemical mechanisms of resistance to persistent organic xenobiotic p-nitrochlorobenzene (NCB of bacterial strains isolated from two cave clays ecosystems – Mushkarova Yama (Podolia, Ukraine and Kuybyshevskaya (Western Caucasus, Abkhazia have been established. It has been determined that chemoorganotrophic karst caves strains could interact with NCB and transform it reducing the nitro group with formation of p-chloroaniline (ClA followed by further destruction of NCB aromatic ring. This explained high resistance of caves strains to NCB. The studied strains could potentially be used in wastewater treatment from nitrochloraromatic compounds.

  8. The first “osteolepiform” tetrapodomorph (Sarcopterygii) from the Paleozoic sequences of the Moravian Karst (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Poukarová, Hedvika; Weiner, Tomáš

    2016-01-01

    Roč. 60, č. 3 (2016), s. 737-745 ISSN 1641-7291 R&D Projects: GA ČR GA14-18183S Institutional support: RVO:67985831 Keywords : Tetrapodomorpha * “Osteolepiformes”, * cosmine * Famennian * Moravo-Silesian Basin * Moravian Karst Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.129, year: 2016

  9. Karst groundwater protection: First application of a Pan-European Approach to vulnerability, hazard and risk mapping in the Sierra de Libar (Southern Spain)

    International Nuclear Information System (INIS)

    Andreo, Bartolome; Goldscheider, Nico; Vadillo, Inaki; Vias, Jesus Maria; Neukum, Christoph; Sinreich, Michael; Jimenez, Pablo; Brechenmacher, Julia; Carrasco, Francisco; Hoetzl, Heinz; Perles, Maria Jesus; Zwahlen, Francois

    2006-01-01

    The European COST action 620 proposed a comprehensive approach to karst groundwater protection, comprising methods of intrinsic and specific vulnerability mapping, validation of vulnerability maps, hazard and risk mapping. This paper presents the first application of all components of this Pan-European Approach to the Sierra de Libar, a karst hydrogeology system in Andalusia, Spain. The intrinsic vulnerability maps take into account the hydrogeological characteristics of the area but are independent from specific contaminant properties. Two specific vulnerability maps were prepared for faecal coliforms and BTEX. These maps take into account the specific properties of these two groups of contaminants and their interaction with the karst hydrogeological system. The vulnerability assessment was validated by means of tracing tests, hydrological, hydrochemical and isotope methods. The hazard map shows the localization of potential contamination sources resulting from human activities, and evaluates those according to their dangerousness. The risk of groundwater contamination depends on the hazards and the vulnerability of the aquifer system. The risk map for the Sierra de Libar was thus created by overlaying the hazard and vulnerability maps

  10. Karst groundwater protection: First application of a Pan-European Approach to vulnerability, hazard and risk mapping in the Sierra de Libar (Southern Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Andreo, Bartolome [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain)]. E-mail: Andreo@uma.es; Goldscheider, Nico [Centre of Hydrogeology, University of Neuchatel, 11 rue Emile-Argand, CH-2007 Neuchatel (Switzerland); Vadillo, Inaki [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain); Vias, Jesus Maria [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain); Neukum, Christoph [Department of Applied Geology, University of Karlsruhe, Kaiserstrasse, 12, D-76128 Karlsruhe (Germany); Sinreich, Michael [Centre of Hydrogeology, University of Neuchatel, 11 rue Emile-Argand, CH-2007 Neuchatel (Switzerland); Jimenez, Pablo [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain); Brechenmacher, Julia [Department of Applied Geology, University of Karlsruhe, Kaiserstrasse, 12, D-76128 Karlsruhe (Germany); Carrasco, Francisco [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain); Hoetzl, Heinz [Department of Applied Geology, University of Karlsruhe, Kaiserstrasse, 12, D-76128 Karlsruhe (Germany); Perles, Maria Jesus [Group of Hydrogeology, Faculty of Science, University of Malaga, Campus de Teatinos, E-29071 Malaga (Spain); Zwahlen, Francois [Centre of Hydrogeology, University of Neuchatel, 11 rue Emile-Argand, CH-2007 Neuchatel (Switzerland)

    2006-03-15

    The European COST action 620 proposed a comprehensive approach to karst groundwater protection, comprising methods of intrinsic and specific vulnerability mapping, validation of vulnerability maps, hazard and risk mapping. This paper presents the first application of all components of this Pan-European Approach to the Sierra de Libar, a karst hydrogeology system in Andalusia, Spain. The intrinsic vulnerability maps take into account the hydrogeological characteristics of the area but are independent from specific contaminant properties. Two specific vulnerability maps were prepared for faecal coliforms and BTEX. These maps take into account the specific properties of these two groups of contaminants and their interaction with the karst hydrogeological system. The vulnerability assessment was validated by means of tracing tests, hydrological, hydrochemical and isotope methods. The hazard map shows the localization of potential contamination sources resulting from human activities, and evaluates those according to their dangerousness. The risk of groundwater contamination depends on the hazards and the vulnerability of the aquifer system. The risk map for the Sierra de Libar was thus created by overlaying the hazard and vulnerability maps.

  11. Using principal component analysis and annual seasonal trend analysis to assess karst rocky desertification in southwestern China.

    Science.gov (United States)

    Zhang, Zhiming; Ouyang, Zhiyun; Xiao, Yi; Xiao, Yang; Xu, Weihua

    2017-06-01

    Increasing exploitation of karst resources is causing severe environmental degradation because of the fragility and vulnerability of karst areas. By integrating principal component analysis (PCA) with annual seasonal trend analysis (ASTA), this study assessed karst rocky desertification (KRD) within a spatial context. We first produced fractional vegetation cover (FVC) data from a moderate-resolution imaging spectroradiometer normalized difference vegetation index using a dimidiate pixel model. Then, we generated three main components of the annual FVC data using PCA. Subsequently, we generated the slope image of the annual seasonal trends of FVC using median trend analysis. Finally, we combined the three PCA components and annual seasonal trends of FVC with the incidence of KRD for each type of carbonate rock to classify KRD into one of four categories based on K-means cluster analysis: high, moderate, low, and none. The results of accuracy assessments indicated that this combination approach produced greater accuracy and more reasonable KRD mapping than the average FVC based on the vegetation coverage standard. The KRD map for 2010 indicated that the total area of KRD was 78.76 × 10 3  km 2 , which constitutes about 4.06% of the eight southwest provinces of China. The largest KRD areas were found in Yunnan province. The combined PCA and ASTA approach was demonstrated to be an easily implemented, robust, and flexible method for the mapping and assessment of KRD, which can be used to enhance regional KRD management schemes or to address assessment of other environmental issues.

  12. Spatiotemporal Variation of Karst Ecosystem Service Values and Its Correlation with Environmental Factors in Northwest Guangxi, China

    Science.gov (United States)

    Zhang, Mingyang; Zhang, Chunhua; Wang, Kelin; Yue, Yuemin; Qi, Xiangkun; Fan, Feide

    2011-11-01

    In this investigation we analyzed the spatiotemporal variation of ecosystem service values (ESVs) and its correlation with numerous environmental factors (EFs) for the karst region of Northwest Guangxi, China, from 1985 to 2005 using remote sensing, geographic information systems (GIS) and statistical techniques. The results indicate that historically ESVs for this karst region decreased from 1985 (109.652 billion Yuan) to 1990 (88.789 billion Yuan) and then increased at the turn of the twenty-first century. However, the ESVs in both 2000 (103.384 billion Yuan) and 2005 (106.257 billion Yuan) never achieved the level recorded in 1985. The total of nutrient cycling, organic production and gas regulation combined were 72.69, 64.57, 70.18 and 72.10% of ESVs in 1985, 1990, 2000 and 2005, respectively. In contrast, the ESVs of water conservation, soil reservation, recreation and culture were determined to be relatively low contributing only 17.44, 23.82, 19.26 and 24.76% of total ESVs, respectively, during these four years. With regards to the spatial distribution of ESVs, larger values were recorded in the west and smaller ones recorded in the east. The most significant factors that were deemed to influence ESVs are annual rainfall, per capita cropland, slope and vegetation coverage. Annual rainfall and slope exert a negative force, whereas per capita cropland and vegetation coverage exert a positive force on ESVs. The results of the study would suggest that ecosystem conditions of this important karst region have been improved as the result of the implementation of rocky desertification control policies.

  13. Dam construction impacts on multiscale characterization of sediment discharge in two typical karst watersheds of southwest China

    Science.gov (United States)

    Li, Zhenwei; Xu, Xianli; Xu, Chaohao; Liu, Meixian; Wang, Kelin

    2018-03-01

    Southwest China, as one of the largest continuous karst areas in the world, is a severely eroded region due to its special geological condition. Thus, soil and water conservation measures such as dam construction have been extensively implemented in this region to control sediment delivery. However, it remains unclear how dam construction affects multiscale variability of sediment discharge (SD) and its potentially influential factors in southwest China. To assess this, annual SD, water discharge (WD), precipitation (PT), potential evapotranspiration (PET), and normalized differential vegetation index (NDVI) data from 1955 to 2015 were obtained from two karst watersheds of Liujiang (no large dams) and Hongshui (dam-controlled). These sites shared the similar climatic conditions. The Mann-Kendal test, Wilcoxon rank-sum test, and continuous wavelet transform analysis was used to detect the trends and periodicity in SD, and wavelet coherence analysis were employed to detect the temporal covariance between SD and WD, PT, PET, and NDVI. Results indicated that the multiscale variability of SD was strongly influenced by dam construction. The annual SD showed significant 4-year periodic oscillation in the Liujiang watershed, while no significant cycles were found in the Hongshui watershed. Dam construction exerted substantial influence on the multiscale correlations between SD and its associated factors. The time scales that the NDVI resonated with SD were concentrated on the periodicity of 2- and 3-year in the Liujiang watershed. In contrast, no significant periodicities were observed in the Hongshu watershed. This study yields a greater understanding of SD dynamics, and is helpful for better watershed management in karst areas of southwest China.

  14. Dynamics Of Karstification: A Model Applied To Hydraulic Structures In Karst Terranes

    Science.gov (United States)

    Dreybrodt, W.

    1992-01-01

    To model the development of karst channels from primary fissures in limestone, a computer simulation of solutional widening of a fracture by calcite agressive water is proposed. The parameters defining the problem are the initial width a0 of the fracture, its length l, and the hydraulic gradient i driving water through it. The dissolution rates limestone determine how fast enlargement of the fractures proceeds. At a calcite concentration, c, far from equilibrium, the dissolution follows a first-order rate law, F(1)=α0(ceq-c); close to the equilibrium concentration, ceq, a slow fourth-order rate law F(4)=β0(ceq-c)4 is valid. The results show that, at the time of initiation, the water flow through the karst channels increases slowly in time until an abrupt increase occurs. After this moment of breakthrough, the channel enlarges rapidly and evenly over its entire length by first-order kinetics. Breakthrough times have been calculated for karstification under natural conditions for low hydraulic gradients as functions of a0, l, and i. Special attention is given to karstification in the vicinity of hydraulic structures where hydraulic gradients are high (>0.5) and channel lengths are below 200 m. We find that the breakthrough event will occur in less than 100 years, if: (i/l) > (5.3·10-8a0 -2.63PCO2 -0.77) where l is in m and a0 is in cm, (i/l) is given in m-1, and PCO2[atm] is the CO2 pressure of the water entering the fracture. After this event, the channels will widen to a width of about 1 cm within only 10 years, which can cause considerable leakage near or through hydraulic structures. Finally, critical values of the parameters i, l, a0, which give the conditions of failure in various types of hydraulic structures are discussed.

  15. Surface and subsurface continuous gravimetric monitoring of groundwater recharge processes through the karst vadose zone at Rochefort Cave (Belgium)

    Science.gov (United States)

    Watlet, A.; Van Camp, M. J.; Francis, O.; Poulain, A.; Hallet, V.; Triantafyllou, A.; Delforge, D.; Quinif, Y.; Van Ruymbeke, M.; Kaufmann, O.

    2017-12-01

    Ground-based gravimetry is a non-invasive and integrated tool to characterize hydrological processes in complex environments such as karsts or volcanoes. A problem in ground-based gravity measurements however concerns the lack of sensitivity in the first meters below the topographical surface, added to limited infiltration below the gravimeter building (umbrella effect). Such limitations disappear when measuring underground. Coupling surface and subsurface gravity measurements therefore allow isolating hydrological signals occurring in the zone between the two gravimeters. We present a coupled surface/subsurface continuous gravimetric monitoring of 2 years at the Rochefort Cave Laboratory (Belgium). The gravity record includes surface measurements of a GWR superconducting gravimeter and subsurface measurements of a Micro-g LaCoste gPhone gravimeter, installed in a cave 35 m below the surface station. The recharge of karstic aquifers is extremely complex to model, mostly because karst hydrological systems are composed of strongly heterogeneous flows. Most of the problem comes from the inadequacy of conventional measuring tools to correctly sample such heterogeneous media, and particularly the existence of a duality of flow types infiltrating the vadose zone: from rapid flows via open conduits to slow seepage through porous matrix. Using the surface/subsurface gravity difference, we were able to identify a significant seasonal groundwater recharge within the karst vadose zone. Seasonal or perennial perched reservoirs have already been proven to exist in several karst areas due to the heterogeneity of the porosity and permeability gradient in karstified carbonated rocks. Our gravimetric experiment allows assessing more precisely the recharge processes of such reservoirs. The gravity variations were also compared with surface and in-cave hydrogeological monitoring (i.e. soil moisture, in-cave percolating water discharges, water levels of the saturated zone). Combined

  16. Life on a block of limestone: Evolutionary, ecological and geological dynamics of isolated malacofaunas on tropical karst

    NARCIS (Netherlands)

    Schilthuizen, M.

    2011-01-01

    The karst formations of southeast Asia are a wonderful evolutionary and ecological experiment, and a sad example of observable extinction (Clements et al., 2006). In this paper, I shall focus on those in Malaysia and, in particular, on the land snail faunas that they support.

  17. Climate change and Mediterranean coastal karst aquifers: the case of Salento (southern Italy)

    OpenAIRE

    Polemio, M.; Romanazzi, A.

    2014-01-01

    Second half of the 20th century was characterized by an increase of groundwater discharge. Numerous aquifers are overexploited in the world and in particular in the Mediterranean area. Problems tie to overexploitation, as piezometric decline and increase of seawater intrusion, are amplified in karst coastal aquifers where the whole effect could be a groundwater quality and quantity degradation. Focusing on Mediterranean countries, most part of coastal aquifers of Spain, France, Portugal, S...

  18. Seasonal changes of organic matter quality and quantity at the outlet of a forested karst system (La Roche Saint Alban, French Alps)

    Science.gov (United States)

    Tissier, Grégory; Perrette, Yves; Dzikowski, Marc; Poulenard, Jérome; Hobléa, Fabien; Malet, Emmanuel; Fanget, Bernard

    2013-03-01

    SummaryBecause of its impact on water quality, organic matter (OM) in karst groundwater has been widely studied. The present article describes a method for monitoring OM in karst aquifers characterized by quick responses to rainfall. This method combines weekly manual sampling and continuous monitoring to provide, qualitative and quantitative information about OM flow. Weekly samples were analyzed for Total Organic Carbon (TOC) content and spectrofluorescence, while continuous monitoring was carried out at the main spring, using a field fluorimeter (310/400-700 nm and 280/300-600 nm) to quantify chromophoric organic matter (COM). The type and quantity of COM were defined by decomposing Excitation Emission Matrices (EEMs) and by applying a 2D fluorescence decomposition method. Continuous monitoring data showed that the dominant COM was humic-like (HL). We found three types of relationship between HL and discharge and between HL and TOC, showing that caution must be exercised when using field fluorimeter measurements to quantify TOC. Each relationship was characterized by global differences in OM content and by the presence of different percentages of non-chromophoric organic matter. These three relationships are associated with changes in hydrology and microorganism activity during the year. We used these relationships to estimate the annual OM flow (about 15 kg/ha/year) and thereby quantify OM flow during the year. Our results show the importance of the non-chromophoric organic matter in such estimation. That work illustrates the need to couple qualitative and quantitative monitoring of OM in karst spring to improve the global comprehension of karst system and of the sources implies in the OM flow.

  19. Spatial resolution of transport parameters in a subtropical karst conduit system during dry and wet seasons

    Science.gov (United States)

    Ender, Anna; Goeppert, Nadine; Goldscheider, Nico

    2018-04-01

    Karst aquifers are characterized by a high degree of hydrologic variability and spatial heterogeneity of transport parameters. Tracer tests allow the quantification of these parameters, but conventional point-to-point experiments fail to capture spatiotemporal variations of flow and transport. The goal of this study was to elucidate the spatial distribution of transport parameters in a karst conduit system at different flow conditions. Therefore, six tracer tests were conducted in an active and accessible cave system in Vietnam during dry and wet seasons. Injections and monitoring were done at five sites along the flow system: a swallow hole, two sites inside the cave, and two springs draining the system. Breakthrough curves (BTCs) were modeled with CXTFIT software using the one-dimensional advection-dispersion model and the two-region nonequilibrium model. In order to obtain transport parameters in the individual sections of the system, a multi-pulse injection approach was used, which was realized by using the BTCs from one section as input functions for the next section. Major findings include: (1) In the entire system, mean flow velocities increase from 183 to 1,043 m/h with increasing discharge, while (2) the proportion of immobile fluid regions decrease; (3) the lowest dispersivity was found at intermediate discharge; (4) in the individual cave sections, flow velocities decrease along the flow direction, related to decreasing gradients, while (5) dispersivity is highest in the middle section of the cave. The obtained results provide a valuable basis for the development of an adapted water management strategy for a projected water-supply system.

  20. Analysis of water control in an underground mine under strong karst media influence (Vazante mine, Brazil)

    Science.gov (United States)

    Ninanya, Hugo; Guiguer, Nilson; Vargas, Eurípedes A.; Nascimento, Gustavo; Araujo, Edmar; Cazarin, Caroline L.

    2018-05-01

    This work presents analysis of groundwater flow conditions and groundwater control measures for Vazante underground mine located in the state of Minas Gerais, Brazil. According to field observations, groundwater flow processes in this mine are highly influenced by the presence of karst features located in the near-surface terrain next to Santa Catarina River. The karstic features, such as caves, sinkholes, dolines and conduits, have direct contact with the aquifer and tend to increase water flow into the mine. These effects are more acute in areas under the influence of groundwater-level drawdown by pumping. Numerical analyses of this condition were carried out using the computer program FEFLOW. This program represents karstic features as one-dimensional discrete flow conduits inside a three-dimensional finite element structure representing the geologic medium following a combined discrete-continuum approach for representing the karst system. These features create preferential flow paths between the river and mine; their incorporation into the model is able to more realistically represent the hydrogeological environment of the mine surroundings. In order to mitigate the water-inflow problems, impermeabilization of the river through construction of a reinforced concrete channel was incorporated in the developed hydrogeological model. Different scenarios for channelization lengths for the most critical zones along the river were studied. Obtained results were able to compare effectiveness of different river channelization scenarios. It was also possible to determine whether the use of these impermeabilization measures would be able to reduce, in large part, the elevated costs of pumping inside the mine.

  1. Sinkhole occurrence in consequence of heavy rainstorms

    Science.gov (United States)

    Parise, Mario; Pisano, Luca; Vennari, Carmela

    2016-04-01

    ) affected the lower sector of a karst depression. Their shape is predominantly circular, but the dimensions are assorted. Some of the landforms are just subdued, and appear to be less developed. Morphometry and shape of the observed sinkholes allow to attribute them to the typology of collapse or cover-collapse sinkholes. Additional sinkholes were triggered in a rural area in the northern part of Monte Sant'Angelo. These are five sinkholes linked to natural cavities, that were activated during the September 2014 storm, and subsequently were enlarged. In the area, terra rossa deposits cover limestone rocks. The largest sinkhole is 25.2 m deep and 12 m wide. From its base, speleological explorations documented a series of pits, going down at least until a depth of -130 m below the ground surface, thus testifying the direct link with the subsurface system of groundwater circulation. The sinkholes occurred in the Gargano area are natural events quite common in karst areas (Waltham et al., 2005; Ford & Williams, 2007; Parise, 2008, 2015b; Gutierrez et al., 2008, 2014; Parise et al., 2015), as a result of intense and/or prolonged rainfall events that increase the superficial and underground outflow. The speed of outflow of large quantities of water may be able to remove unconsolidated soil, creating new ways of underground water circulation, and as a consequence the material on the surface could collapse in the underlying cavities (Parise et al., 2015b). Documenting these phenomena, especially in relation to intense rainstorms, is of great importance, since in the great majority of cases they go unreported, especially where (as is the Gargano case) the karst lands are thickly covered by forests, or develop in mostly rural areas. The collection of direct data from the observed sinkholes allowed us, further, to update the chronological catalogue of sinkholes in Italy, managed by CNR-IRPI since several years (Parise & Vennari, 2013) within the framework of research projects on karst

  2. Human and natural impacts on fluvial and karst depressions of the Maya Lowlands

    Science.gov (United States)

    Beach, Timothy; Luzzadder-Beach, Sheryl; Dunning, Nicholas; Cook, Duncan

    2008-10-01

    This paper begins to differentiate the major drivers and chronology of erosion and aggradation in the fluvial and fluviokarst landscapes of the southern and central Maya Lowlands. We synthesize past research on erosion and aggradation and add new data from water, soils, radiocarbon dating, and archaeology to study the quantity, timing, and causes of aggradation in regional landscape depressions. Geomorphic findings come from many excavations across a landscape gradient from upland valleys, karst sinks, and fans into the coastal plain floodplains and depressions. Findings from water chemistry show that sources in the uplands have low quantities of dissolved ions but water in the coastal plains has high amounts of dissolved ions, often nearly saturated in calcium and sulfate. We found significant geomorphic complexity in the general trends in upland karst sinks. In a few instances, sediments preserve Late Pleistocene paleosols, buried 2-3 m, though many more have distinct middle to late Holocene paleosols, buried 1-2 m, after c. 2300 BP (Maya Early to Late Preclassic). From 2300-1100 BP (Late Preclassic to Classic Periods), the landscape aggraded from five main mechanisms: river flooding, climatic instability, accelerated erosion, ancient Maya landscape manipulation, and gypsum precipitation from a rise in a water table nearly saturated in calcium and sulfate ions. Evidence exists for two or three high magnitude floods, possibly driven by hurricanes. Moreover, lake-core and geophysical studies from the Petén Lakes region have shown high rates of deposition of silicate clays ('Maya Clays') starting and peaking during the Maya Preclassic and continuing to be high through the Late Classic. The main driver on upland karst depressions, the Petén lakes, upland valleys, and fans was accelerated soil erosion, but water table rise, probably driven by sea-level rise, was the main driver on the wetlands of the coastal plain because the aggraded sediments here are dominantly

  3. A GIS-based methodology to quantitatively define an Adjacent Protected Area in a shallow karst cavity: the case of Altamira cave.

    Science.gov (United States)

    Elez, J; Cuezva, S; Fernandez-Cortes, A; Garcia-Anton, E; Benavente, D; Cañaveras, J C; Sanchez-Moral, S

    2013-03-30

    Different types of land use are usually present in the areas adjacent to many shallow karst cavities. Over time, the increasing amount of potentially harmful matter and energy, of mainly anthropic origin or influence, that reaches the interior of a shallow karst cavity can modify the hypogeal ecosystem and increase the risk of damage to the Palaeolithic rock art often preserved within the cavity. This study proposes a new Protected Area status based on the geological processes that control these matter and energy fluxes into the Altamira cave karst system. Analysis of the geological characteristics of the shallow karst system shows that direct and lateral infiltration, internal water circulation, ventilation, gas exchange and transmission of vibrations are the processes that control these matter and energy fluxes into the cave. This study applies a comprehensive methodological approach based on Geographic Information Systems (GIS) to establish the area of influence of each transfer process. The stratigraphic and structural characteristics of the interior of the cave were determined using 3D Laser Scanning topography combined with classical field work, data gathering, cartography and a porosity-permeability analysis of host rock samples. As a result, it was possible to determine the hydrogeological behavior of the cave. In addition, by mapping and modeling the surface parameters it was possible to identify the main features restricting hydrological behavior and hence direct and lateral infiltration into the cave. These surface parameters included the shape of the drainage network and a geomorphological and structural characterization via digital terrain models. Geological and geomorphological maps and models integrated into the GIS environment defined the areas involved in gas exchange and ventilation processes. Likewise, areas that could potentially transmit vibrations directly into the cave were identified. This study shows that it is possible to define a

  4. U-isotopes and (226)Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas.

    Science.gov (United States)

    Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

    2016-07-01

    Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ((238)U, (235)U and (234)U) and (226)Ra by alpha spectrometry were determined. The activity concentration of (238)U presented a large variation from around 1.1 to 65 mBq L(-1). Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The (234)U/(238)U activity ratios were higher than unity for all samples (1.1-3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. (226)Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10(2) mBq L(-1)); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed (226)Ra/(234)U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). (226)Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest (234)U/(238)U activity ratios, probably due to fast uniform bulk mineral dissolution

  5. Groundwater contamination and the relationship between water chemistry and biotic components in a karst system (Bihor Mountains, Romania

    Directory of Open Access Journals (Sweden)

    Laura Epure

    2014-12-01

    Full Text Available The physical and chemical characteristics, microbial contaminat ion, and meiofauna of the Ocoale-Gheţar-Dobreşti karst system (Bihor Mountains, Romania were studied in order to assess the natural water quality by an interdisciplinary study. A total of 60 water samples were collected seasonally from 7 sites. Physico-chemical results showed a typical composition of karst waters, except for one site, where Ca2+ was absent, pH was very low, and the abundance and diversity of meiofauna were highest, demonstrating life support even for the most sensitive animals. No significant chemical pollution was found, but microbial contamination occurred in all samples, according to the national water quality standards of the analyzed springs. The Canonical Correlation Analysis and the Canonical Correspondence Analysis performed showed a strong connection between pH, nitrates and faecal pollution, indicating also a direct connection between microbial contaminants and dissolved oxygen.

  6. Community composition and cold tolerance of soil Collembola in a collapse karst doline with strong microclimate inversion

    Czech Academy of Sciences Publication Activity Database

    Raschmanová, N.; Miklisová, D.; Kováč, L.; Šustr, Vladimír

    2015-01-01

    Roč. 70, č. 6 (2015), s. 802-811 ISSN 0006-3088 Grant - others:VEGA(SK) 1/0199/14; VEGA(SK) 1/3267/06 Institutional support: RVO:60077344 Keywords : cold tolerance * collapse doline * karst landform * microclimatic gradient * soil Collembola Subject RIV: EG - Zoology Impact factor: 0.719, year: 2015

  7. Geochemical and statistical evidence of recharge, mixing, and controls on spring discharge in an eogenetic karst aquifer

    Science.gov (United States)

    Moore, Paul J.; Martin, Jonathan B.; Screaton, Elizabeth J.

    2009-10-01

    SummaryInformation about sources of recharge, distributions of flow paths, and the extent of water-rock reactions in karst aquifers commonly result from monitoring spring chemistry and discharge. To investigate the relationship between spring characteristics and the complexities of karst aquifers, we couple variations in surface- and groundwater chemistry to physical conditions including river stage, precipitation, and evapotranspiration (ET) within a sink-rise system through a 6-km portion of the Upper Floridan aquifer (UFA) in north-central Florida. Principal component analysis (PCA) of time series major-element compositions suggests that at least three sources of water affect spring discharge, including allogenic recharge into a swallet, diffuse recharge through a thin vadose zone, and water upwelling from deep within the aquifer. The deep-water source exerts the strongest influence on water chemistry by providing a majority of Na +, Mg 2+, K +, Cl -, and SO42- to the system. Anomalously high temperature at one of several monitoring wells reflects vertical flow of about 1 m/year. Mass-balance calculations suggest diffuse recharge and deep-water upwelling can provide up to 50% of the spring discharge; however, their contributions depend on head gradients between the conduit and surrounding aquifer matrix, which are influenced by variations in precipitation, ET, and river stage. Our results indicate that upwelling from deep flow paths may provide significant contributions of water to spring discharge, and that monitoring only springs limits interpretations of karst systems by masking critical components of the aquifer, such as water sources and flow paths. These results also suggest the matrix in eogenetic aquifers is a major pathway for flow even in a system dominated by conduits.

  8. Heat exchange modeling in a multilayered karst aquifer affected by seawater intrusion

    Directory of Open Access Journals (Sweden)

    Luca Vettorello

    2015-11-01

    Full Text Available A Feflow thermohaline model has been implemented in order to study borehole heat exchangers (BHEs activity in a coastal aquifer in the South of Italy (Province of Lecce, Puglia Region. The modeled closed-loop system consists of two double u-pipe heat exchangers, installed in 200 meters deep boreholes. The main purpose of numerical modeling was to forecast thermal plume extension in groundwater after a long period of heat exchange, calculating temperature trends in observation points during a 10 years transport simulation. The complex geological structure, including calcarenites, fractured limestones and a deep karst aquifer, has been translated into a multilayered model, with a depth-related parameter distribution, assigning different values of hydraulic, thermal and chemical properties to each layer. In particular saltwater concentration has been taken into account, considering the influence of seawater intrusion on the heat transport density-dependent model. Parameters assignment was based on experimental datasets collected during initial field investigations, including thermal characterization of soil samples and GRTs, together with historical hydrogeological and hydrochemical measures and previous groundwater surveys. After model structure configuration and aquifers parameterization, a sensitivity analysis on porosity and heat dispersivity has been conducted, to evaluate their influence on thermal transport phenomena with a multiple scenarios approach, considering in particular the uncertainty related to secondary porosity in karst systems. Feflow simulation represented the first step in environmental compatibility evaluation for the BHE plant, waiting for the necessary model calibration with groundwater temperature monitoring trends.

  9. The conservation value of karst dolines for vascular plants in woodland habitats of Hungary: refugia and climate change

    Directory of Open Access Journals (Sweden)

    Zoltán Bátori

    2014-01-01

    Full Text Available Limestone (karst surfaces in Hungary are rich in dolines, in which many endangered vascular plant species occur. To date, the majority of studies dealing with doline vegetation have focused on the local rather than the landscape level, without using comparative data from other areas. However, in this study we aimed to compare the vegetation pattern and species composition of dolines under different climate regimes of Hungary with regard to regional species pools. The fieldwork was carried out between 2005 and 2012. Twenty dolines were selected in the Mecsek Mountains (southern Hungary and nine dolines in the Aggtelek Karst area (northern Hungary. More than 900 vascular plants and more than 2000 plots were included in the study. The moving split window (MSW technique, nestedness analysis and principal coordinates analysis (PCoA were used to reveal the vegetation patterns in dolines. Although we found remarkable differences between the species composition of the two regions, dolines of both regions play a similar role in the preservation of different groups of species. Many plants, in particular mountain species, are restricted to the bottom of dolines where appropriate environmental conditions exist. In addition, depending on the doline geometry, many species of drier and warmer forests have colonized the upper slopes and rims. Thus, we can conclude that karst dolines of Hungary can be considered as reservoirs for many vascular plant species, therefore they are particularly important from a conservation point of view. Moreover, these dolines will likely become increasingly indispensable refugia for biodiversity under future global warming.

  10. Spatial and statistical methods for correlating the interaction between groundwater contamination and tap water exposure in karst regions

    Science.gov (United States)

    Padilla, I. Y.; Rivera, V. L.; Macchiavelli, R. E.; Torres Torres, N. I.

    2016-12-01

    Groundwater systems in karst regions are highly vulnerable to contamination and have an enormous capacity to store and rapidly convey pollutants to potential exposure zones over long periods of time. Contaminants in karst aquifers used for drinking water purposes can, therefore, enter distributions lines and the tap water point of use. This study applies spatial and statistical analytical methods to assess potential correlations between contaminants in a karst groundwater system in northern Puerto Rico and exposure in the tap water. It focuses on chlorinated volatile organic compounds (CVOC) and phthalates because of their ubiquitous presence in the environment and the potential public health impacts. The work integrates historical data collected from regulatory agencies and current field measurements involving groundwater and tap water sampling and analysis. Contaminant distributions and cluster analysis is performed with Geographic Information System technology. Correlations between detection frequencies and contaminants concentration in source groundwater and tap water point of use are assessed using Pearson's Chi Square and T-Test analysis. Although results indicate that correlations are contaminant-specific, detection frequencies are generally higher for total CVOC in groundwater than tap water samples, but greater for phthalates in tap water than groundwater samples. Spatial analysis shows widespread distribution of CVOC and phthalates in both groundwater and tap water, suggesting that contamination comes from multiple sources. Spatial correlation analysis indicates that association between tap water and groundwater contamination depends on the source and type of contaminants, spatial location, and time. Full description of the correlations may, however, need to take into consideration variable anthropogenic interventions.

  11. Tracking changing X-ray contrast media application to an urban-influenced karst aquifer in the Wadi Shueib, Jordan

    International Nuclear Information System (INIS)

    Zemann, Moritz; Wolf, Leif; Grimmeisen, Felix; Tiehm, Andreas; Klinger, Jochen; Hötzl, Heinz; Goldscheider, Nico

    2015-01-01

    Sewage input into a karst aquifer via leaking sewers and cesspits was investigated over five years in an urbanized catchment. Of 66 samples, analyzed for 25 pharmaceuticals, 91% indicated detectable concentrations. The former standard iodinated X-ray contrast medium (ICM) diatrizoic acid was detected most frequently. Remarkably, it was found more frequently in groundwater (79%, median: 54 ng/l) than in wastewater (21%, 120 ng/l), which is supposed to be the only source in this area. In contrast, iopamidol, a possible substitute, spread over the aquifer during the investigation period whereas concentrations were two orders of magnitude higher in wastewater than in groundwater. Knowledge about changing application of pharmaceuticals thus is essential to assess urban impacts on aquifers, especially when applying mass balances. Since correlated concentrations provide conclusive evidence that, for this catchment, nitrate in groundwater rather comes from urban than from rural sources, ICM are considered useful tracers. - Highlights: • 5 year survey on pharmaceutical occurrence in an urban influenced karst catchment. • Continued occurrence of diatrizoic acid in 5 springs despite only few occurrences in possible sources like wastewater. • Iopamidol was observed to spread within the aquifer during the monitoring period. • Increasing pharmaceutical detection rates in springs correlate with increasing E. coli numbers and nitrate concentrations. • Correlation analysis of diatrizoic acid and nitrate reveal urban areas as most likely source of nitrate. - The paper discusses challenges of using pharmaceuticals as tracers by the example of diatrizoic acid which occurred at a higher frequency in a karst aquifer than in the wastewater source

  12. Discovery of ancient Roman "highway" reveals geomorphic changes in karst environments during historic times.

    Science.gov (United States)

    Bernardini, Federico; Vinci, Giacomo; Forte, Emanuele; Furlani, Stefano; Pipan, Michele; Biolchi, Sara; De Min, Angelo; Fragiacomo, Andrea; Micheli, Roberto; Ventura, Paola; Tuniz, Claudio

    2018-01-01

    Sinkholes are a well-known geologic hazard but their past occurrence, useful for subsidence risk prediction, is difficult to define, especially for ancient historic times. Consequently, our knowledge about Holocene carbonate landscapes is often limited. A multidisciplinary study of Trieste Karst (Italy), close to early Roman military fortifications, led to the identification of possible ancient road tracks, cut by at least one sinkhole. Electrical Resistivity Tomography through the sinkhole has suggested the presence of a cave below its bottom, possibly responsible of the sinkhole formation, while Ground Penetrating Radar has detected no tectonic disturbances underneath the tracks. Additionally, archaeological surveys led to the discovery of over 200 Roman shoe hobnails within or close to the investigated route. According to these data, the tracks are interpreted as the remains of a main Roman road, whose itinerary has been reconstructed for more than 4 km together with other elements of ancient landscape. Our results provide the first known evidence of a Roman main road swallowed by sinkholes and suggest that Holocene karst landscapes could be much different from what previously believed. In fact, sinkholes visible nowadays in the investigated region could have been flat areas filled by sediments up to the Roman time.

  13. Isotope study in the Alpine karst region of Rawil (Switzerland)

    International Nuclear Information System (INIS)

    Schotterer, U.; Siegenthaler, U.; Oeschger, H.; Wildberger, A.; Nabholz, W.

    1978-01-01

    An isotope study in the karst of the high Alps in Switzerland is described. From 1973 to 1978 discharge, 3 H, delta 18 O, conductivity and temperature were measured in representative springs. The springs are influenced by snowmelt in late spring and summer, by rain in late summer and autumn, and in the winter period, when infiltration stops, by reservoir water. Since tritium in precipitation in the last years scattered irregularly in time and space, the residence time of winter baseflow (2-4 years) could not be determined very precisely. The pronounced difference in delta 18 O between several springs allowed us to estimate the difference in mean altitude of their recharge areas. (orig.) [de

  14. Karst aquifer in Galichica and possibilities for water supply to Ohrid with ground -water

    International Nuclear Information System (INIS)

    Mirchovski, Vojo; Kekich, Aleksandar; Spasovski, Orce; Mirchovski, Vlado

    2009-01-01

    In this paper are presented some hydrogeological features of the karst aquifer in Mt Galichica, which contains important quantities of ground-water that can to used for the water supply of the town Ohrid. Based on the hydrogeological data are given three solutions that be can to used for water supply of Ohrid, the first one is to drill of deep wells, combination of deep and shallow wells, as well as construction of horizontal galleries.

  15. Secondary halite deposits in the Iranian salt karst: general description and origin

    Directory of Open Access Journals (Sweden)

    Filippi Michal

    2011-07-01

    overgrown by halite precipitates. If the tip isblocked by halite precipitates, the brine remaining in the straw will seep through the walls and helictites start to grow in some places.Macrocrystalline skeletal deposits and straw stalactites usually grow after a major rain event when dripping is strong, whilemicrocrystalline speleothems are formed continuously during much longer periods and ultimately (usually overgrow the other typesof speleothems during dry periods. The rate of secondary halite deposition is much faster compared to the carbonate karst. Someforms increase more than 0.5 m during the first year after a strong rain event; however, the age of speleothems is difficult to estimate,as they are often combinations of segments of various ages and growth periods alternate with long intervals of inactivity.Described forms may be considered in many cases as the analogues of forms found in the carbonate karst. As they are created in ashort time period the conditions of their origin are often still visible or can be reconstructed. The described halite forms can thus beused for verification of the origin of various carbonate forms. Some of the described forms bear clear evidence of the paleo-watersurface level (transition of the skeletal form to halite crystals and vice versa. Other kinds of deposits are potential indicators of themicroclimate under which they developed (humidity close to the deliquescence relative humidity.

  16. Mg- and K-bearing borates and associated evaporites at Eagle Borax spring, Death Valley, California: A spectroscopic exploration

    Science.gov (United States)

    Crowley, J.K.

    1996-01-01

    Efflorescent crusts at the Eagle Borax spring in Death Valley, California, contain an array of rare Mg and K borate minerals, several of which are only known from one or two other localities. The Mg- and/or K-bearing borates include aristarainite, hydroboracite, kaliborite, mcallisterite, pinnoite, rivadavite, and santite. Ulexite and probertite also occur in the area, although their distribution is different from that of the Mg and K borates. Other evaporite minerals in the spring vicinity include halite, thenardite, eugsterite, gypsum-anhydrite, hexahydrite, and bloedite. Whereas the first five of these minerals are found throughout Death Valley, the last two Mg sulfates are more restricted in occurrence and are indicative of Mg-enriched ground water. Mineral associations observed at the Eagle Borax spring, and at many other borate deposits worldwide, can be explained by the chemical fractionation of borate-precipitating waters during the course of evaporative concentration. The Mg sulfate and Mg borate minerals in the Eagle Borax efflorescent crusts point to the fractionation of Ca by the operation of a chemical divide involving Ca carbonate and Na-Ca borate precipitation in the subsurface sediments. At many other borate mining localities, the occurrence of ulexite in both Na borate (borax-kernite) and Ca borate (ulexite-colemanite) deposits similarly reflects ulexite's coprecipitation with Ca carbonate at an early concentration stage. Such ulexite may perhaps be converted to colemanite by later reaction with the coexisting Ca carbonate - the latter providing the additional Ca2+ ions needed for the conversion. Mg and Ca-Mg borates are the expected late-stage concentration products of waters forming ulexite-colemanite deposits and are therefore most likely to occur in the marginal zones or nearby mud facies of ulexite-colemanite orebodies. Under some circumstances, Mg and Ca-Mg borates might provide a useful prospecting guide for ulexite-colemanite deposits

  17. Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds

    Science.gov (United States)

    Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie

    2018-01-01

    Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content. PMID:29652811

  18. Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds

    Directory of Open Access Journals (Sweden)

    Zhenming Zhang

    2018-04-01

    Full Text Available Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.

  19. Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds.

    Science.gov (United States)

    Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie; Huang, Xianfei

    2018-04-13

    Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km², 4.50 km², and 1.87 km², respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.

  20. Soil quality changes in land degradation as indicated by soil chemical, biochemical and microbiological properties in a karst area of southwest Guizhou, China

    Science.gov (United States)

    Zhang, Pingjiu; Li, Lianqing; Pan, Genxing; Ren, Jingchen

    2006-12-01

    Not only the nutritional status and biological activity but also the soil ecological functioning or soil health has been impacted profoundly by land degradation in the karst area of southwest China where the karst ecosystems are generally considered as extremely vulnerable to land degradation under intensified land-use changes. The objectives of this study are to elucidate the changes in overall soil quality by a holistic approach of soil nutritional, biological activity, and soil health indicators in the karst area as impacted by intense cultivation and vegetation degradation. Topsoil samples were collected on selected eco-tesserae in a sequence of land degradation in a karst area of southwest Guizhou in 2004. The soil nutrient pools of organic carbon (Corg), extractable extracellular carbon (Cext), total soil nitrogen (Nt), alkali-hydrolyzable nitrogen (Nah), total phosphorus (Pt), available phosphorus (Pa) were analyzed by wet soil chemistry. The soil biological properties were studied by means of measurements of microbial biomass carbon (both by fumigation-extraction, FE-Cmic, and by calculation from substrate-incubation respiration, SIR-Cmic) of respiration [respiration without addition of substrates, basal respiration (BR), and potential respiration (PR) with substrate-incubation] and of soil enzyme activities (invertase, urease, and alkaline phosphatase). Soil health status was assessed by simple indices of Cmic/Corg and BR/Cmic in conjunction with bacterial community structures determined by polymerase chain reaction and denaturing gradient gel electrophoresis. While the nutritional pool parameters, such as Corg and Cext, described basically the changes in soil life-supporting capacity with cultivation interference and vegetation declined, those parameters of biological activity such as FE-Cmic, SIR, and SIR-Cmic as well as bacterial community structures measured by molecular method evidenced well the changes in soil functioning for ecosystem health with

  1. Do shallow soil, low water availability, or their combination increase the competition between grasses with different root systems in karst soil?

    Science.gov (United States)

    Zhao, Yajie; Li, Zhou; Zhang, Jing; Song, Haiyan; Liang, Qianhui; Tao, Jianping; Cornelissen, Johannes H C; Liu, Jinchun

    2017-04-01

    Uneven soil depth and low water availability are the key limiting factors to vegetation restoration and reconstruction in limestone soils such as in vulnerable karst regions. Belowground competition will possibly increase under limited soil resources. Here, we investigate whether low resource availability (including shallow soil, low water availability, and shallow soil and low water availability combined) stimulates the competition between grasses with different root systems in karst soil, by assessing their growth response, biomass allocation, and morphological plasticity. In a full three-way factorial blocked design of soil depth by water availability by neighbor identity, we grew Festuca arundinacea (deep-rooted) and Lolium perenne (shallow-rooted) under normal versus shallow soil depth, high versus low water availability, and in monoculture (conspecific neighbor) versus mixture (neighbor of the other species). The key results were as follows: (1) total biomass and aboveground biomass in either of the species decreased with reduction of resources but were not affected by planting patterns (monoculture or mixture) even at low resource levels. (2) For F. arundinacea, root biomass, root mass fraction, total root length, and root volume were higher in mixture than in monoculture at high resource level (consistent with resource use complementarity), but lower in mixture than in monoculture at low resource levels (consistent with interspecific competition). In contrast for L. perenne, either at high or low resource level, these root traits had mostly similar values at both planting patterns. These results suggest that deep-rooted and shallow-rooted plant species can coexist in karst regions under current climatic regimes. Declining resources, due to shallow soil, a decrease in precipitation, or combined shallow soil and karst drought, increased the root competition between plants of deep-rooted and shallow-rooted species. The root systems of deep-rooted plants may be

  2. Boron isotope evidence for the involvement of non-marine evaporites in the origin of the Broken Hill ore deposits

    Science.gov (United States)

    Slack, J.F.; Palmer, M.R.; Stevens, B.P.J.

    1989-01-01

    IDENTIFYING the palaeogeographic setting and mode of origin of stratabound ore deposits can be difficult in high-grade metamorphic terranes, where the effects of metamorphism may obscure the nature of the protoliths. Here we report boron isotope data for tourmalines from the early Proterozoic Broken Hill block, in Australia, which hosts giant lead-zinc-silver sulphide deposits. With one exception the 11B/10B ratios are lower than those for all other tourmalines from massive sulphide deposits and tour-malinites elsewhere in the world. We propose that these low ratios reflect leaching of boron from non-marine evaporitic borates by convecting hydrothermal fluids associated with early Proterozoic continental rifting. A possible modern analogue is the Salton Sea geothermal field in California. ?? 1989 Nature Publishing Group.

  3. Factors controlling accumulation of soil organic carbon along vegetation succession in a typical karst region in Southwest China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shujuan [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Wei [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); Wang, Kelin, E-mail: kelin@isa.ac.cn [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); Pan, Fujing [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Shan [Changsha university, Changsha 410003 (China); Shu, Shiyan [Changjiang Project Supervision & Consultancy Co. Ltd, Wuhan 430010 (China); Changjiang Ecology (Hubei) Technology Development LLC, Wuhan 430010 (China)

    2015-07-15

    Vegetation succession enhances the accumulation of carbon in the soil. However, little is known about the mechanisms underlying soil organic carbon (SOC) accumulation in different vegetation types in the karst region of Southwest China. The goal of this study was to identify and prioritize the effects of environmental parameters, including soil physico-chemical properties, microbial biomass, enzyme activities, and litter characteristics, on SOC accumulation along a vegetation succession sere (grassland, shrubland, secondary forest, and primary forest) in the karst landscape of Southwest China. Relationships between these parameters and SOC were evaluated by redundancy analysis. The results showed that SOC accumulation was significantly different among vegetation types (P < 0.01) and increased with vegetation succession (from 29.10 g·kg{sup −1} in grassland to 73.92 g·kg{sup −1} in primary forest). Soil biochemistry and physical characteristics significantly affected the accumulation of SOC. Soil microbial biomass showed a predominant effect on SOC in each of the four vegetation types. In addition, the soil physical property (especially the silt content) was another controlling factor in the early stages (grassland), and urease activity and saccharase activity were important controlling factors in the early-middle and middle-late stages, respectively. Litter characteristics only showed mild effects on SOC accumulation. Variation partitioning analysis showed that the contribution of sole main factors to SOC variation decreased, while the interaction effect among parameters increased along the succession gradient. - Highlights: • Vegetation restoration is conducive to soil carbon sequestration in karst areas. • The factors controlling SOC accumulation differed along vegetation succession. • The interaction effect among significant factors became more and more prominent along succession.

  4. Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink-Rise system, north Florida, USA

    Science.gov (United States)

    Jin, Jin; Zimmerman, Andrew R.; Moore, Paul J.; Martin, Jonathan B.

    2014-03-01

    Spatiotemporal variations in dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major ions concentrations and other geochemical parameters including stable carbon isotopes of DIC (δ13CDIC), were measured in surface water and deep and shallow well water samples of the Santa Fe River Sink-Rise eogenetic karst system, north Florida, USA. Three end-member water sources were identified: one DOC-rich/DIC-poor/δ13CDIC-depleted, one DOC-poor/DIC-rich/δ13CDIC-enriched, and one enriched in major ions. Given their spatiotemporal distributions, they were presumed to represent soil water, upper aquifer groundwater, and deep aquifer water sources, respectively. Using assumed ratios of Na+, Cl, and SO42- for each end-member, a mixing model calculated the contribution of each water source to each sample. Then, chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations. In general, carbonate mineral dissolution occurred throughout the Sink-Rise system, surface waters were net autotrophic and the subsurface was in metabolic balance, i.e., no net DOC or DIC production or consumption. However, there was evidence for chemolithoautotrophy, perhaps by hydrogen oxidizing microbes, at some deep aquifer sites. Mineralization of this autochthonous natural dissolved organic matter (NDOM) led to localized carbonate dissolution as did surface water-derived NDOM supplied to shallow well sites during the highest flow periods. This study demonstrates linkages between hydrology, abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality, karst morphologic evolution, and hydrogeologic projects such as aquifer storage and recovery in karst systems.

  5. Intensive exploitation of a karst aquifer leads to Cryptosporidium water supply contamination.

    Science.gov (United States)

    Khaldi, S; Ratajczak, M; Gargala, G; Fournier, M; Berthe, T; Favennec, L; Dupont, J P

    2011-04-01

    Groundwater from karst aquifers is an important source of drinking water worldwide. Outbreaks of cryptosporidiosis linked to surface water and treated public water are regularly reported. Cryptosporidium oocysts are resistant to conventional drinking water disinfectants and are a major concern for the water industry. Here, we examined conditions associated with oocyst transport along a karstic hydrosystem, and the impact of intensive exploitation on Cryptosporidium oocyst contamination of the water supply. We studied a well-characterized karstic hydrosystem composed of a sinkhole, a spring and a wellbore. Thirty-six surface water and groundwater samples were analyzed for suspended particulate matter, turbidity, electrical conductivity, and Cryptosporidium and Giardia (oo)cyst concentrations. (Oo)cysts were identified and counted by means of solid-phase cytometry (ChemScan RDI(®)), a highly sensitive method. Cryptosporidium oocysts were detected in 78% of both surface water and groundwater samples, while Giardia cysts were found in respectively 22% and 8% of surface water and groundwater samples. Mean Cryptosporidium oocyst concentrations were 29, 13 and 4/100 L at the sinkhole, spring and wellbore, respectively. Cryptosporidium oocysts were transported from the sinkhole to the spring and the wellbore, with respective release rates of 45% and 14%, suggesting that oocysts are subject to storage and remobilization in karst conduits. Principal components analysis showed that Cryptosporidium oocyst concentrations depended on variations in hydrological forcing factors. All water samples collected during intensive exploitation contained oocysts. Control of Cryptosporidium oocyst contamination during intensive exploitation is therefore necessary to ensure drinking water quality. Copyright © 2011. Published by Elsevier Ltd.

  6. Evaporite dissolution relevant to the WIPP site, northern Delaware Basin, southeastern New Mexico

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1982-01-01

    Evaluation of the threat of natural dissolution of host evaporites to the integrity of the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico has taken into consideration (1) the volume of missing rock salt, (2) the occurrence (or not) of characteristic dissolution brines, (3) geomorphic features, some of which are unrelated to dissolution, and (4) the time intervals over which dissolution may have been active. Even under the assumption that all missing halite was originally present and has been removed by dissolution, there is no evidence of active preferential removal of the lower Salado Formation halite by any geologically reasonable process. The geologic record contains evidence of dissolution in the Triassic and Jurassic; to constrain all removal of basinal halite to the late Cenozoic yields an unrealistically high rate of removal. Application to the lower Salado of a stratabound mechanism known to be active in Nash Draw, a near-surface feature within the Basin, allows a minimum survival time of 2,500,000 years to be predicted for the subsurface facility for storage of radioactive waste at WIPP. This calculation is based on an analysis of all known dissolution features in the Delaware Basin, and takes into account the wetter (pluvial) climate during the past 600,000 years. 2 figures, 1 table

  7. Impact of landfills, domestic and industrial waste on the aquifer in Raipur city and contribution of karst feature to the groundwater contaminations

    International Nuclear Information System (INIS)

    Sinha, U.K.; Deodhar, A.; Kulkarni, U.P.; Sharma, Suman

    2004-01-01

    Karst features (landscapes that result from dissolution and surface drainage of carbonate terrains) are potentially a large source of water. They have distinctive features, which distinguish them from fissured and porous aquifers. These features include a general lack of permanent surface streams, existence of surface holes into which surface stream sink, presence of underground big channels and large springs etc. Karst environments are used for potable water supply as well as disposal sites for municipal, agricultural and industrial waste dumping. The peculiar geomorphologic and hydrological features of karst make them highly vulnerable for groundwater pollution. The ease with which they can be polluted make a fit case of taking protection measures in advance. Raipur is a major business, educational center as well as capital city of Chhattisgarh state in India. The city has been rapidly expanding during the last two decades, as a result of rapid industrialisation and various economic developments. Wastes generated from a wide variety of industrial, commercial, agricultural and domestic activities are dumped into pits or low - lying area around the Raipur City. The climate in the area is characterised by very hot summer and well distributed rain over four months during monsoon season. Monsoon precipitation begins from mid June and generally remains active till the end of September. The average annual precipitation is ∼1250 mm. In the study area, groundwater lies in the karstified nature of geological formation and is naturally susceptible to contamination by landfills, domestic and industrial wastes. The karstification feature is exposed to the surface in Raipur city at many places. Environmental isotopes ( 2 H, 3 H, 18 O and 13 C) as well as chemistry of the water samples were used to identify a few places, which are prone to contamination in Raipur city. Deterioration of the groundwater quality is not alarming due to thin shale (impervious layer) cover over the

  8. Karst tiankengs as refugia for indigenous tree flora amidst a degraded landscape in southwestern China.

    Science.gov (United States)

    Su, Yuqiao; Tang, Qiming; Mo, Fuyan; Xue, Yuegui

    2017-06-26

    We conducted floristic and community analyses to compare the floristic composition, forest structure, taxonomic richness, and species diversity between two tiankeng (large doline, or sinkhole) habitats and two outside-tiankeng habitats of forest fragments in a degraded karst area in southwestern China. We found remarkably higher taxonomic richness in the tiankeng habitats than in the outside-tiankeng habitats at the species, generic, and familial levels. The inside-tiankeng habitats had higher floristic diversity but lower dominance. The remarkably higher uniqueness at all taxonomic levels and the much larger tree size in the two tiankeng habitats than in the outside-tiankeng habitats demonstrated the old-growth and isolated nature of the tiankeng flora. Plot-scale species richness, Shannon-Wiener index, Pielou's evenness, and Berger-Parker dominance significantly differed across habitats. Heterogeneity in floristic composition at the species, generic, and familial levels was extremely significant across habitats. In pairwise comparisons, except for the Chuandong Tiankeng-Shenmu Tiankeng pair, all the pairs showed significant between-habitat heterogeneity in floristic composition. Our results suggest that as oases amidst the degraded karst landscape, tiankengs serve as modern refugia that preserve old-growth forest communities with their rich floristic diversity, and can provide a model for habitat conservation and forest restoration in that area.

  9. Taking the mystery out of mathematical model applications to karst aquifers—A primer

    Science.gov (United States)

    Kuniansky, Eve L.

    2014-01-01

    Advances in mathematical model applications toward the understanding of the complex flow, characterization, and water-supply management issues for karst aquifers have occurred in recent years. Different types of mathematical models can be applied successfully if appropriate information is available and the problems are adequately identified. The mathematical approaches discussed in this paper are divided into three major categories: 1) distributed parameter models, 2) lumped parameter models, and 3) fitting models. The modeling approaches are described conceptually with examples (but without equations) to help non-mathematicians understand the applications.

  10. Hydrogeology of Pico Frentes Karst system (Iberian range, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Rosas, P.; Sanz, E.; Menendez-Pidal, I.

    2016-07-01

    The karst system of Pico Frentes has developed within an Upper Cretaceous calcareous series whose welldefined folded geometry determines that its aquifer reserves are held mainly in three hydraulically-connected synclines, with a groundwater capacity of between 5 and 7 hm3 . The recharge to this unconfined peneplain aquifer is autogenous and diffuse. On a large scale, groundwater flow is directed by the base of the synclines, while on a small scale, it flows along groundwater conduits towards the Fuentetoba Spring (210 l/s) and source of the River Mazos (50 l/s), following a highly variable flow regime of low inertia, with other smaller discharges emanating during periods of high water. Analysis of hydrographs of these springs indicates a very variable rate system and little power regulating natural, characteristic of a typical karstic aquifer, with great capacity for renewal and low residence time. Using hydrogram simulations of these upwellings using a mathematical rainfall-runoff model, a detailed quantification of the average water balance was made for a twenty-year time series. This water balance consists of 16,86 hm3 rainfall (100%); natural recharge, 8,35 hm3 (49,53%); EVT 8,50 hm3 (50,41%); pumped groundwater abstractions, 0,01hm3 (0,06%); surface runoff, 0 hm3, groundwater transfers to other aquifer, 0 hm3. (Author)

  11. Soil erosion evolution and spatial correlation analysis in a typical karst geomorphology using RUSLE with GIS

    Science.gov (United States)

    Zeng, Cheng; Wang, Shijie; Bai, Xiaoyong; Li, Yangbing; Tian, Yichao; Li, Yue; Wu, Luhua; Luo, Guangjie

    2017-07-01

    Although some scholars have studied soil erosion in karst landforms, analyses of the spatial and temporal evolution of soil erosion and correlation analyses with spatial elements have been insufficient. The lack of research has led to an inaccurate assessment of environmental effects, especially in the mountainous area of Wuling in China. Soil erosion and rocky desertification in this area influence the survival and sustainability of a population of 0.22 billion people. This paper analyzes the spatiotemporal evolution of soil erosion and explores its relationship with rocky desertification using GIS technology and the revised universal soil loss equation (RUSLE). Furthermore, this paper analyzes the relationship between soil erosion and major natural elements in southern China. The results are as follows: (1) from 2000 to 2013, the proportion of the area experiencing micro-erosion and mild erosion was at increasing risk in contrast to areas where moderate and high erosion are decreasing. The area changes in this time sequence reflect moderate to high levels of erosion tending to convert into micro-erosion and mild erosion. (2) The soil erosion area on the slope, at 15-35°, accounted for 60.59 % of the total erosion area, and the corresponding soil erosion accounted for 40.44 %. (3) The annual erosion rate in the karst region decreased much faster than in the non-karst region. Soil erosion in all of the rock outcrop areas indicates an improving trend, and dynamic changes in soil erosion significantly differ among the various lithological distribution belts. (4) The soil erosion rate decreased in the rocky desertification regions, to below moderate levels, but increased in the severe rocky desertification areas. The temporal and spatial variations in soil erosion gradually decreased in the study area. Differences in the spatial distribution between lithology and rocky desertification induced extensive soil loss. As rocky desertification became worse, the erosion

  12. Soil erosion evolution and spatial correlation analysis in a typical karst geomorphology using RUSLE with GIS

    Directory of Open Access Journals (Sweden)

    C. Zeng

    2017-07-01

    Full Text Available Although some scholars have studied soil erosion in karst landforms, analyses of the spatial and temporal evolution of soil erosion and correlation analyses with spatial elements have been insufficient. The lack of research has led to an inaccurate assessment of environmental effects, especially in the mountainous area of Wuling in China. Soil erosion and rocky desertification in this area influence the survival and sustainability of a population of 0.22 billion people. This paper analyzes the spatiotemporal evolution of soil erosion and explores its relationship with rocky desertification using GIS technology and the revised universal soil loss equation (RUSLE. Furthermore, this paper analyzes the relationship between soil erosion and major natural elements in southern China. The results are as follows: (1 from 2000 to 2013, the proportion of the area experiencing micro-erosion and mild erosion was at increasing risk in contrast to areas where moderate and high erosion are decreasing. The area changes in this time sequence reflect moderate to high levels of erosion tending to convert into micro-erosion and mild erosion. (2 The soil erosion area on the slope, at 15–35°, accounted for 60.59 % of the total erosion area, and the corresponding soil erosion accounted for 40.44 %. (3 The annual erosion rate in the karst region decreased much faster than in the non-karst region. Soil erosion in all of the rock outcrop areas indicates an improving trend, and dynamic changes in soil erosion significantly differ among the various lithological distribution belts. (4 The soil erosion rate decreased in the rocky desertification regions, to below moderate levels, but increased in the severe rocky desertification areas. The temporal and spatial variations in soil erosion gradually decreased in the study area. Differences in the spatial distribution between lithology and rocky desertification induced extensive soil loss. As rocky desertification

  13. Molecular indicators for palaeoenvironmental change in a Messinian evaporitic sequence (Vena del Gesso, Italy) II. Stratigraphic changes in abundances and (13)C contents of free and sulphur-bound skeletons in a single marl bed

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kenig, F.; Frewin, N.L.; Hayes, J.M.

    1995-01-01

    The extractable organic matter of 10 immature samples from a marl bed of one evaporitic cycle of the Vena del Gesso sediments (Gessoso-solfifera Fm., Messinian, Italy) was analyzed quantitatively for free hydrocarbons and organic sulphur compounds. Nickel boride was used as a desulphurizing agent to

  14. Effects of mining activities on evolution of water quality of karst waters in Midwestern Guizhou, China: evidences from hydrochemistry and isotopic composition.

    Science.gov (United States)

    Li, Xuexian; Wu, Pan; Han, Zhiwei; Zha, Xuefang; Ye, Huijun; Qin, Yingji

    2018-01-01

    Zhijin coal-mining district, located in Midwestern Guizhou Province, has been extensively exploited for several decades. The discharge of acid mine drainage (AMD) has constituted a serious threat to local water environmental quality, which greatly affected the normal use of local people. The Permian limestone aquifer is the essential potable water supply for local people, which covered under the widely distributed coal seams. To investigate the origin of the water, the evolutionary processes, and the sources of dissolved sulfate in the karst waters, the mine water, surface water, and groundwater near the coal mines were sampled for stable isotopes (H, O, and S) and conventional hydrochemical analysis. The results of hydrochemistry and isotopic composition indicate that the regional surface water and partial karst groundwater are obviously affected by coal-mining activities, which is mainly manifested in the increase of water solute concentration and the change of hydrochemical types. The isotopic composition of δ 2 H H2O and δ 18 O H2O indicates that the major recharge source of surface water and the groundwater is atmospheric precipitation and that it is influenced obviously by evaporation in the recharge process. The surface water is mainly controlled by the oxidation of pyrite, as well as the dissolution of carbonate rocks, whereas that of natural karst waters is influenced by the dissolution of carbonate rocks. The resulting δ 34 S SO4 values suggest that the dissolved sulfate source in the surface water is mainly pyrite oxidation but atmospheric precipitation for the karst groundwater. Given the similar chemistry and isotopic composition between surface water and partial groundwater, it is reasonable to assume that most of the dissolved sulfate source in part of the groundwater was derived through the oxidation of pyrite in the coal. Furthermore, the contamination of the surface water and partial groundwater from the coal seam has occurred distinctly in the

  15. Unearthing a hidden treasure: 60 years of karst research in the Far West Rand, South Africa

    Directory of Open Access Journals (Sweden)

    Aljoscha Schrader

    2015-05-01

    Full Text Available Karstified dolomitic formations situated in the Far West Rand goldfield of the Witwatersrand Basin constitute a significant groundwater resource in semi?arid South Africa and would be of strategic importance for alleviating the increasing water stress in nearby metropolitan areas. The deep?level gold mines operating below the dolomites have suffered from large volumes of dolomitic groundwater flowing into the mine voids, rendering mining both expensive and hazardous. In order to secure safe and economical mining, the overlying dolomites were dewatered. Here we review research over 60 years, conducted in three of the four major dolomitic compartments affected by dewatering. After more than six decades of research, these aquifers are arguably the most investigated karst systems in South Africa, and possibly worldwide. The data generated are, in many respects, unique, as many measurements can never be repeated, covering stochastic events such as a major water inrush into mine workings and some of the most catastrophic sinkhole developments ever recorded. Given the potential value for improving the understanding of general and local karst hydrogeology, our main goal for this paper is to alert the scientific community to the existence of this resource of mostly unpublished data and research. A no less important aim is to support a systematic collation of these studies which are in danger of being irretrievably lost as mines increasingly close down. Ecological and economic impacts of the flooding of mines in and around Johannesburg emphasise the lack of reliable historical mine data to optimally address the matter. We provide the first comprehensive, yet not exhaustive, overview on the existing studies, briefly discussing scientific content as well as obstacles for utilising the scattered, and often non?peer reviewed, information sources.

  16. Conversion of Blue Water into Green Water for Improving Utilization Ratio of Water Resources in Degraded Karst Areas

    Directory of Open Access Journals (Sweden)

    Ke Chen

    2016-12-01

    Full Text Available Vegetation deterioration and soil loss are the main causes of more precipitation leakages and surface water shortages in degraded karst areas. In order to improve the utilization of water resources in such regions, water storage engineering has been considered; however, site selection and cost associated with the special karstic geological structure have made this difficult. According to the principle of the Soil Plant Atmosphere Continuum, increasing both vegetation cover and soil thickness would change water cycle process, resulting in a transformation from leaked blue water (liquid form into green water (gas or saturated water form for terrestrial plant ecosystems, thereby improving the utilization of water resources. Using the Soil Vegetation Atmosphere Transfer model and the geographical distributed approach, this study simulated the conversion from leaked blue water (leakage into green water in the environs of Guiyang, a typical degraded karst area. The primary results were as follows: (1 Green water in the area accounted for <50% of precipitation, well below the world average of 65%; (2 Vegetation growth played an important role in converting leakage into green water; however, once it increased to 56%, its contribution to reducing leakage decreased sharply; (3 Increasing soil thickness by 20 cm converted the leakage considerably. The order of leakage reduction under different precipitation scenarios was dry year > normal year > rainy year. Thus, increased soil thickness was shown effective in improving the utilization ratio of water resources and in raising the amount of plant ecological water use; (4 The transformation of blue water into green water, which avoids constructions of hydraulic engineering, could provide an alternative solution for the improvement of the utilization of water resources in degraded karst area. Although there are inevitable uncertainties in simulation process, it has important significance for overcoming similar

  17. Hydrological connectivity in the karst critical zone: an integrated approach

    Science.gov (United States)

    Chen, X.; Zhang, Z.; Soulsby, C.; Cheng, Q.; Binley, A. M.; Tao, M.

    2017-12-01

    Spatial heterogeneity in the subsurface is high, evidenced by specific landform features (sinkholes, caves etc.) and resulting in high variability of hydrological processes in space and time. This includes complex exchange of various flow sources (e.g. hillslope springs and depression aquifers) and fast conduit flow and slow fracture flow. In this paper we integrate various "state-of-the-art" methods to understand the structure and function of this understudied critical zone environment. Geophysical, hydrometric and hydrogeochemical tools are used to characterize the hydrological connectivity of the cockpit karst critical zone in a small catchment of Chenqi, Guizhou province, China. Geophysical surveys, using electrical resistivity tomography (ERT), identified the complex conduit networks that link flows between hillslopes and depressions. Statistical time series analysis of water tables and discharge responses at hillslope springs and in depression wells and underground channels showed different threshold responses of hillslope and depression flows. This reflected the differing relative contribution of fast and slow flow paths during rainfall events of varying magnitude in the hillslope epikarst and depression aquifer in dry and wet periods. This showed that the hillslope epikarst receives a high proportion of rainfall recharge and is thus a main water resource in the catchment during the drought period. In contrast, the depression aquifer receives fast, concentrated hillslope flows during large rainfall events during the wet period, resulting in the filling of depression conduits and frequent flooding. Hydrological tracer studies using water temperatures and stable water isotopes (δD and δ18O) corroborated this and provided quantitative information of the mixing proportions of various flow sources and insights into water travel times. This revealed how higher contributions of event "new" water (from hillslope springs and depression conduits displaces "old" pre

  18. New updated results of paleomagnetic dating of cave deposits exposed in Za Hájovnou Cave, Javoříčko Karst

    Czech Academy of Sciences Publication Activity Database

    Kadlec, Jaroslav; Čížková, Kristýna; Šlechta, Stanislav

    2014-01-01

    Roč. 70, 1-2 (2014), s. 27-34 ISSN 0036-5343 Institutional support: RVO:67985530 ; RVO:67985831 Keywords : Javoříčko Karst * Za Hájovnou Cave * Early and Middle Pleistocene * paleomagnetic dating Subject RIV: DB - Geology ; Mineralogy

  19. SWAT Model Prediction of Phosphorus Loading in a South Carolina Karst Watershed with a Downstream Embayment

    Science.gov (United States)

    Devendra M. Amatya; Manoj K. Jha; Thomas M. Williams; Amy E. Edwards; Daniel R.. Hitchcock

    2013-01-01

    The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for monthly streamflow predictions from tributaries draining three potential source areas as well as the downstream R-E, followed by TP loadings using data...

  20. Teaching resources in speleology and karst: a valuable educational tool

    Directory of Open Access Journals (Sweden)

    De Waele Jo

    2010-01-01

    Full Text Available There is a growing need in the speleological community of tools that make teaching of speleology and karst much easier. Despite the existence of a wide range of major academic textbooks, often the caver community has a difficult access to such material. Therefore, to fill this gap, the Italian Speleological Society, under the umbrella of the Union International de Spéléologie, has prepared a set of lectures, in a presentation format, on several topics including geology, physics, chemistry, hydrogeology, mineralogy, palaeontology, biology, microbiology, history, archaeology, artificial caves, documentation, etc. These lectures constitute the “Teaching Resources in Speleology and Karst”, available online. This educational tool, thanks to its easily manageable format, can constantly be updated and enriched with new contents and topics.

  1. Comprehensive surface geophysical investigation of karst caves ahead of the tunnel face: A case study in the Xiaoheyan section of the water supply project from Songhua River, Jilin, China

    Science.gov (United States)

    Bin, Liu; Zhengyu, Liu; Shucai, Li; Lichao, Nie; Maoxin, Su; Huaifeng, Sun; Kerui, Fan; Xinxin, Zhang; Yonghao, Pang

    2017-09-01

    This paper describes the application of a comprehensive surface geophysical investigation of underground karst systems ahead of the tunnel face in the Xiaoheyan section in the main line of the water supply project from Songhua River, located in Jilin, China. To make an accurate investigation, Surface Electrical Resistivity Tomography (S-ERT), Transient Electromagnetic Method (TEM), Geological Drilling (Geo-D) and Three-dimensional Cross-hole Electrical Resistivity Tomography (3D cross-hole ERT) were applied to gain a comprehensive interpretation. To begin with, S-ERT and TEM are adopted to detect and delineate the underground karst zone. Based on the detection results, surface and in-tunnel Geo-D are placed in major areas with more specific and accurate information gained. After that, survey lines of 3D cross-hole ERT are used to conduct detailed exploration towards underground karst system. In the comprehensive investigation, it is the major question to make the best of prior information so as to promote the quality of detection. The paper has put forward strategies to make the full use of effective information in data processing and the main ideas of those strategies include: (1) Take the resistivity distribution of the subsurface stratum gained by S-ERT inversion as the initial model of TEM inversion; (2) Arrange borehole positions with the results of S-ERT and TEM. After that, gain more accurate information about resistivity of subsurface stratum using those boreholes located; (3) Through the comprehensive analysis of the information about S-ERT, TEM and Geo-D, set the initial model of 3D cross-hole resistivity inversion and meanwhile, gain the variation range of stratum resistivity. At last, a 3D cross-hole resistivity inversion based on the incorporated initial model and inequality constraint is conducted. Constrained inversion and joint interpretation are realized by the effective use of prior information in comprehensive investigation, helping to suppress

  2. [Effect of irregular bedrock topography on the soil profile pattern of water content in a Karst hillslope.

    Science.gov (United States)

    Jia, Jin Tian; Fu, Zhi Yong; Chen, Hong Song; Wang, Ke Lin; Zhou, Wei Jun

    2016-06-01

    Based on three manually excavated trenches (projection length of 21 m, width of 1 m) along a typical Karst hillslope, the changing trends for soil-bedrock structure, average water content of soil profile and soil-bedrock interface water content along each individual trench were studied. The effect of irregular bedrock topography on soil moisture distribution was discussed. The results showed that the surface topography was inconsistent with the bedrock topography in the Karst hill-slopes. The bedrock topography was highly irregular with a maximum variation coefficient of 82%. The distribution pattern of soil profile of moisture was significantly affected by the underlying undulant bedrock. The soil water content was related to slope position when the fluctuation was gentle, and displayed a linear increase from upslope to downslope. When the bedrock fluctuation increased, the downslope linear increasing trend for soil water content became unapparent, and the spatial continuity of soil moisture was weakened. The soil moisture was converged in rock dents and cracks. The average water content of soil profile was significantly positively correlated with the soil-bedrock interface water content, while the latter responded more sensitively to the bedrock fluctuation.

  3. Management of an Underground River to Overcome Water Scarcity in the Gunung Sewu Karst Area, Indonesia

    Directory of Open Access Journals (Sweden)

    Choirul Amin

    2017-07-01

    Full Text Available Since people living in a karst area periodically face a crisis due to a lack of fresh water, it is necessary to re-evaluate the ability to use water resources. An appropriate and effective management is required to use available water resource sustainably. We describe a management process of exploring underground river in karst region as water resources. The activities completed included four phases, namely exploration, pre-lifting activities, the water lifting and post-lifting activities. The exploration phase included speleological surveys and data collection for the cave mouth using remote sensing instrument. The pre-lifting was done to prepare various requirements before the lifting process was completed. The water lifting phase consisted of the construction of an underground river dam, the installation of submersible pumps, the construction of reservoirs and the installation of piping to connect to the public hydrant. The post-lifting phase was mainly conducted to organise water distribution evenly. This management model was evidenced to successfully overcome drought in Pucung village by providing fresh water to the local community. Moreover, this model promoted residents’ cost savings by reducing their expenses for buying water from IDR 50,000/m3 to IDR 3,500/m3 (1,300 percent.

  4. Characterisation of karst hydrogeology in Western Ireland using geophysical and hydraulic modelling techniques

    Directory of Open Access Journals (Sweden)

    T. McCormack

    2017-04-01

    New hydrological insights for the region: Results suggest two primary pathways of northwards groundwater flow in the catchment, a fault which discharges offshore, and a ∼2 m diameter karst conduit running underneath the catchment lowlands against the prevailing geological dip. This conduit, whose existence was suspected but never confirmed, links a large ephemeral lake to the coast where it discharges intertidally. Hydraulic modelling indicates that the conduit network is a complex mixture of constrictions with multiple inlets and outlets. Two ephemeral lakes are shown to be hydraulically discontinuous, either drained separately or linked by a low pressure channel.

  5. Polygenetic Karsted Hardground Omission Surfaces in Lower Silurian Neritic Limestones: a Signature of Early Paleozoic Calcite Seas

    Science.gov (United States)

    James, Noel P.; Desrochers, André; Kyser, Kurt T.

    2015-04-01

    Exquisitely preserved and well-exposed rocky paleoshoreline omission surfaces in Lower Silurian Chicotte Formation limestones on Anticosti Island, Quebec, are interpreted to be the product of combined marine and meteoric diagenesis. The different omission features include; 1) planar erosional bedding tops, 2) scalloped erosional surfaces, 3) knobs, ridges, and swales at bedding contacts, and 4) paleoscarps. An interpretation is proposed that relates specific omission surface styles to different diagenetic-depositional processes that took place in separate terrestrial-peritidal-shallow neritic zones. Such processes were linked to fluctuations in relative sea level with specific zones of diagenesis such as; 1) karst corrosion, 2) peritidal erosion, 3) subtidal seawater flushing and cementation, and 4) shallow subtidal deposition. Most surfaces are interpreted to have been the result of initial extensive shallow-water synsedimentary lithification that were, as sea level fell, altered by exposure and subaerial corrosion, only to be buried by sediments as sea level rose again. This succession was repeated several times resulting in a suite of recurring polyphase omission surfaces through many meters of stratigraphic section. Synsedimentary cloudy marine cements are well preserved and are thus interpreted to have been calcitic originally. Aragonite components are rare and thought to have to have been dissolved just below the Silurian seafloor. Large molluscs that survived such seafloor removal were nonetheless leached and the resultant megamoulds were filled with synsedimentary calcite cement. These Silurian inner neritic-strandline omission surfaces are temporally unique. They are part of a suite of marine omission surfaces that are mostly found in early Paleozoic neritic carbonate sedimentary rocks. These karsted hardgrounds formed during a calcite-sea time of elevated marine carbonate saturation and extensive marine cement precipitation. The contemporaneous greenhouse

  6. Large scale afforestation projects mitigate degradation and increase the stability of the karst ecosystems in southwest China

    Science.gov (United States)

    Yue, Y.; Tong, X.; Wang, K.; Fensholt, R.; Brandt, M.

    2017-12-01

    With the aim to combat desertification and improve the ecological environment, mega-engineering afforestation projects have been launched in the karst regions of southwest China around the turn of the new millennium. A positive impact of these projects on vegetation cover has been shown, however, it remains unclear if conservation efforts have been able to effectively restore ecosystem properties and reduce the sensitivity of the karst ecosystem to climate variations at large scales. Here we use passive microwave and optical satellite time series data combined with the ecosystem model LPJ-GUESS and show widespread increase in vegetation cover with a clear demarcation at the Chinese national border contrasting the conditions of neighboring countries. We apply a breakpoint detection to identify permanent changes in vegetation time series and assess the vegetation's sensitivity against climate before and after the breakpoints. A majority (74%) of the breakpoints were detected between 2001 and 2004 and are remarkably in line with the implementation and spatial extent of the Grain to Green project. We stratify the counties of the study area into four groups according to the extent of Grain to Green conservation areas and find distinct differences between the groups. Vegetation trends are similar prior to afforestation activities (1982-2000), but clearly diverge at a later stage, following the spatial extent of conservation areas. Moreover, vegetation cover dynamics were increasingly decoupled from climatic influence in areas of high conservation efforts. Whereas both vegetation resilience and resistance were considerably improved in areas with large conservation efforts thereby showing an increase in ecosystem stability, ongoing degradation and an amplified sensitivity to climate variability was found in areas with limited project implementation. Our study concludes that large scale conservation projects can regionally contribute to a greening Earth and are able to

  7. Spatio-Temporal Variation and Impact Factors for Vegetation Carbon Sequestration and Oxygen Production Based on Rocky Desertification Control in the Karst Region of Southwest China

    Directory of Open Access Journals (Sweden)

    Mingyang Zhang

    2016-01-01

    Full Text Available The Grain to Green Program (GTGP and eco-environmental emigration have been employed to alleviate poverty and control rocky desertification in the Southwest China Karst region. Carbon sequestration and oxygen production (CSOP is used to indicate major ecological changes, because they involve complex processes of material circulation and energy flow. Using remote sensing images and weather records, the spatiotemporal variation of CSOP was analyzed in a typical karst region of northwest Guangxi, China, during 2000–2010 to determine the effects of the Chinese government’s ecological rehabilitation initiatives implemented in 1999. An increase with substantial annual change and a significant increase (20.94%, p < 0.05 in variation were found from 2000 to 2010. CSOP had a highly clustered distribution in 2010 and was correlated with precipitation and temperature (9.18% and 8.96%, respectively, p < 0.05. CSOP was significantly suppressed by human activities (p < 0.01, r = −0.102 but was consistent with the intensity of GTGP (43.80% positive. The power spectrum of CSOP was consistent with that of the gross domestic product. These results indicate that ecological services were improved by rocky desertification control in a typical karst region. The results may provide information to evaluate the efficiency of ecological reconstruction projects.

  8. Estimating Rheological Parameters of Anhydrite from Folded Evaporite sequences: Implications for Internal Dynamics of Salt Structure

    Science.gov (United States)

    Adamuszek, Marta; Dabrowski, Marcin; Schmalholz, Stefan M.; Urai, Janos L.; Raith, Alexander

    2015-04-01

    Salt structures have been identified as a potential target for hydrocarbon, CO2, or radioactive waste storage. The most suitable locations for magazines are considered in the thick and relatively homogeneous rock salt layers. However, salt structures often consist of the evaporite sequence including rock salt intercalated with other rock types e.g.: anhydrite, gypsum, potassium and magnesium salt, calcite, dolomite, or shale. The presence of such heterogeneities causes a serious disturbance in the structure management. Detailed analysis of the internal architecture and internal dynamics of the salt structure are crucial for evaluating them as suitable repositories and also their long-term stability. The goal of this study is to analyse the influence of the presence of anhydrite layers on the internal dynamics of salt structures. Anhydrite is a common rock in evaporite sequences. Its physical and mechanical properties strongly differ from the properties of rock salt. The density of anhydrite is much higher than the density of salt, thus anhydrite is likely to sink in salt causing the disturbance of the surrounding structures. This suggestion was the starting point to the discussion about the long-term stability of the magazines in salt structures [1]. However, the other important parameter that has to be taken into account is the viscosity of anhydrite. The high viscosity ratio between salt and anhydrite can restrain the layer from sinking. The rheological behaviour of anhydrite has been studied in laboratory experiments [2], but the results only provide information about the short-term behaviour. The long-term behaviour can be best predicted using indirect methods e.g. based on the analysis of natural structures that developed over geological time scale. One of the most promising are fold structures, the shape of which is very sensitive to the rheological parameters of the deforming materials. Folds can develop in mechanically stratified materials during layer

  9. A new small karst-dwelling species of Cyrtodactylus (Reptilia: Squamata: Gekkonidae) from Java, Indonesia.

    Science.gov (United States)

    Riyanto, Awal; Bauer, Aaron M; Yudha, Donan Satria

    2014-04-07

    A new small karst-dwelling species of the genus Cyrtodactylus is described from East Java and Special Province of Yogyakarta, Indonesia. Cyrtodactylus semiadii sp. nov. is a small species (SVL to 47.1 mm in females, 42.1 mm in males) distinguished from all other congeners by unique characters combination: short, robust, cylindrical tail, indistinct ventrolateral folds, absence of precloacal groove, absence of enlarged femoral scales, absence of precloacal and femoral pores and lack of enlarged median subcaudal scales. It is the third member of the genus recorded from Java. 

  10. Quantitative assessment of key parameters in qualitative vulnerability methods applied in karst systems based on an integrated numerical modelling approach

    Science.gov (United States)

    Doummar, Joanna; Kassem, Assaad

    2017-04-01

    In the framework of a three-year PEER (USAID/NSF) funded project, flow in a Karst system in Lebanon (Assal) dominated by snow and semi arid conditions was simulated and successfully calibrated using an integrated numerical model (MIKE-She 2016) based on high resolution input data and detailed catchment characterization. Point source infiltration and fast flow pathways were simulated by a bypass function and a high conductive lens respectively. The approach consisted of identifying all the factors used in qualitative vulnerability methods (COP, EPIK, PI, DRASTIC, GOD) applied in karst systems and to assess their influence on recharge signals in the different hydrological karst compartments (Atmosphere, Unsaturated zone and Saturated zone) based on the integrated numerical model. These parameters are usually attributed different weights according to their estimated impact on Groundwater vulnerability. The aim of this work is to quantify the importance of each of these parameters and outline parameters that are not accounted for in standard methods, but that might play a role in the vulnerability of a system. The spatial distribution of the detailed evapotranspiration, infiltration, and recharge signals from atmosphere to unsaturated zone to saturated zone was compared and contrasted among different surface settings and under varying flow conditions (e.g., in varying slopes, land cover, precipitation intensity, and soil properties as well point source infiltration). Furthermore a sensitivity analysis of individual or coupled major parameters allows quantifying their impact on recharge and indirectly on vulnerability. The preliminary analysis yields a new methodology that accounts for most of the factors influencing vulnerability while refining the weights attributed to each one of them, based on a quantitative approach.

  11. CITOGENETICS EFFECTS INDUCED BY THE ASCORBIC ACID TREATMENT OF LARIX DECIDUA MILL. SSP. CARPATICA AND PICEA ABIES (L. KARST

    Directory of Open Access Journals (Sweden)

    Ioana Ieremia

    2006-08-01

    Full Text Available The paper present the influence of ascorbic acid upon the mitotic division of Larix decidua Mill ssp. carpatica and Picea abies (L. Karst. The treatment is applied of two variants, germinated seed in ascorbic acid (variantAand germinated seeds in disttilate water, than treated with ascorbic acid in 3 concentrations (variant B.

  12. The geomorphology and hydrogeology of the karstic Islands Maratua, East Kalimantan, Indonesia: the potential and constraints for tourist destination development

    Science.gov (United States)

    Haryono, E.; Sasongko, M. H. D.; Barianto, D. H.; Setiawan, J. B.; Hakim, A. A.; Zaenuri, A.

    2018-04-01

    Maratua Island is one of the islands of Berau District, East Kalimantan which has great potential of natural beauty for tourism development. The area currently is one of famous tourist destination in East Kalimantan which is a carbonate reef built-up or so-called karst island. This paper is an endeavor 1) to unveil geomorphological and hydrogeological characteristics of the island, and 2) to recommend Island development as a tourist destination. Maratua Island is a V shape atoll with the open lagoon. Six geomorphological units were found on the island, i.e., fringing reef, beach, marine terrace, karst ridge, structural valley, and lagoon. Caves are also found in the karst ridge and the coast as an inundated passage. Three structural depressions in the karst ridge are other unique geomorphological feature in the area of which a marine lake environment with jellyfish is inhabited. The island is typified by two different aquifer units, i.e., porous media and fractured media aquifer. Porous aquifer lies on the beach of Boibukut area. Fractured-aquifer characterizes the other geomorphological units in the area. Freshwater accordingly is found in the beach area with a limited amount. Unfortunately, the groundwater in the marine terrace and karst ridge are saline. Maratua Island has enormous potential for tourism destination development. The major tourist activities in the area based on the geomorphological unit are snorkeling and diving (in fringing reef and lagoo n), hiking, cave exploration and marine lake exploration and cave diving (in karst ridge and structural valley); recreation and picnic (beach). The major limitation in the area is a shortage of freshwater resource and land. Limited water supply should be extracted from the beach area of Bohe Bukut village. Groundwater extraction from the beach area of Bohe Bukut must be for drinking water only. Supply of drinking water should be substituted from collected rainwater or desalination from sea water and water in

  13. Hydraulics of epiphreatic flow of a karst aquifer

    Science.gov (United States)

    Gabrovšek, Franci; Peric, Borut; Kaufmann, Georg

    2018-05-01

    The nature of epiphreatic flow remains an important research challenge in karst hydrology. This study focuses on the flood propagation along the epiphreatic system of Reka-Timavo system (Kras/Carso Plateau, Slovenia/Italy). It is based on long-term monitoring of basic physical parameters (pressure/level, temperature, specific electric conductivity) of ground water in six active caves belonging to the flow system. The system vigorously responds to flood events, with stage rising >100 m in some of the caves. Besides presenting the response of the system to flood events of different scales, the work focuses on the interpretation of recorded hydrographs in view of the known distribution and size of conduits and basic hydraulic relations. Furthermore, the hydrographs were used to infer the unknown geometry between the observation points. This way, the main flow restrictors, overflow passages and large epiphreatic storages were identified. The assumptions were tested with a hydraulic model, where the inversion procedure was used for an additional parameter optimisation. Time series of temperature and specific electric conductivity were used to assess the apparent velocities of flow between consecutive points.

  14. Karst groundwater vulnerability mapping to the pollution: Case of Dir springs located between EL KSIBA and Ouaoumana (High Atlas, Morocco)

    Science.gov (United States)

    Alili, L.; Boukdir, A.; Maslouhi, M. R.; Ikhmerdi, H.

    2018-05-01

    The study area is located in the north of the province of Beni Mellal, it covers the Piedmont of the high Atlas between El Ksiba and Ouaoumana. It is characterized by a poorly developed hydrographic network and the presence of very important karstic forms. These forms condition the rapid infiltration to the karstic springs are the subject of this study. In this work we presented a method of mapping the vulnerability to pollution of Karstic springs located between El Ksiba and Ouaoumana. To do this, we have introduced a vulnerability index called F which takes into account four parameters (EPIK): Development of the Epikarst, importance of the protective cover, infiltration conditions and development of the Karst network. The overlay of the thematic maps of these parameters through a GIS software (ArcGIS) gave us a map of the vulnerability to contamination on the whole hydrogeological basin of the springs.

  15. Flow Dependence Assessment for Fate and Transport of DNAPL in Karst Media

    Science.gov (United States)

    Carmona, M.; Padilla, I. Y.

    2017-12-01

    DNAPLs are a group of organic compounds, which exhibit high fluid density, relatively aqueous solubility, and a high level of toxicity. It is also very persistent and remains in the environment long after been released. Massive production of these compounds, their constant use and poor disposal methods have increased the occurrence of these contaminants in groundwater systems. The physico-chemical properties of DNAPL, combined with the high variation of groundwater flow causes contaminants to behave unpredictably in such aquifer. This research focuses on fate and transport of trichloroethylene (which is one of the most frequent DNAPL found) in a karstified limestone physical model (KLPM) at two different flow rates. The KLPM represents a real case of a saturated confined karst aquifer consisting of a porous limestone block enclosed in a stainless-steel tank with fifteen horizontal sampling ports. After injection of pure TCE solvent into a steady groundwater flow field, samples are taken spatially and temporally and analyzed volumetrically and analytically with HPLC. Data show pure TCE volumes are collected at the beginnings of the experiment in sampling ports located near the injection port. Results from the constructed temporal distributions curves at different spatial locations show spatial variations related to the limestone block heterogeneity. Rapid response to TCE concentrations is associated with preferential flow paths. Slow response with long tailing is indicative of diffusive transport in the rock matrix and mass transport rates limitations. Although, high flow rates show greater mass removal of TCE by dissolving its NAPL, pure TCE accumulates at all flow rates studied. Overall, results show that karstified limestone has a high capacity to rapidly transport, as well as store and slowly release TCE pure and dissolved phase for long periods of time. They also show that fate and transport of contaminants in karst environments is significantly flow dependent.

  16. Overexploitation of karst spring as a measure against water scarcity.

    Science.gov (United States)

    Dimkić, Dejan; Dimkić, Milan; Soro, Andjelko; Pavlović, Dusan; Jevtić, Goran; Lukić, Vladimir; Svrkota, Dragan

    2017-09-01

    Water scarcity, especially in the hydrologically critical part of the year, is a problem often present in many cities and regions, particularly in arid and sub-arid areas. Climate change and human water demand compound the problem. This paper discusses a climate change adaptation measure-the possibility of karst spring overexploitation, where there is a siphon-shaped cavity inside the mountain. The pilot area is near the city of Niš, where a decreasing precipitation trend has already been observed and is expected to continue in the future. The paper also presents some basic information related to the pilot area and undertaken investigations. The project, successfully implemented in 2004, has provided the city of Niš with an additional amount of 200 l/s of spring water during the most critical part of the year.

  17. Regional inventory of karst activity in the Valley and Ridge Province, eastern Tennessee: Phase 1

    International Nuclear Information System (INIS)

    Newton, J.G.; Tanner, J.M.

    1987-09-01

    A data collection form was developed for use in compiling information in the inventory. Information sources included files on subsidence, state and county highway departments, county agents and executives, soil conservation service representative, etc. Data obtained included location, date of occurrence, number of subsidence features at the reported site, size, topographic setting, geologic setting, and probable causative factors. The regional inventory obtained information on over 300 historic subsidence events at more than 200 sites in East Tennessee. Areas having the greatest areal density of active subsidence include Hamblen, Jefferson, and Loudon Counties. Reported subsidence events occurred between 1945 and 1986. The Knox Group dolomites account for about two-thirds of all reported sinkholes in the inventory. Most of the karst activity occurs in valleys or flat areas. In cases where causative factors could be established, the combination of surface water drainage alteration or impoundment combined with soil disturbance associated with construction activity were most often precursors to subsidence. 54 refs., 10 figs., 4 tabs

  18. Effect of vegetation types on soil arbuscular mycorrhizal fungi and nitrogen-fixing bacterial communities in a karst region.

    Science.gov (United States)

    Liang, Yueming; Pan, Fujing; He, Xunyang; Chen, Xiangbi; Su, Yirong

    2016-09-01

    Arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria play important roles in plant growth and recovery in degraded ecosystems. The desertification in karst regions has become more severe in recent decades. Evaluation of the fungal and bacterial diversity of such regions during vegetation restoration is required for effective protection and restoration in these regions. Therefore, we analyzed relationships among AM fungi and nitrogen-fixing bacteria abundances, plant species diversity, and soil properties in four typical ecosystems of vegetation restoration (tussock (TK), shrub (SB), secondary forest (SF), and primary forest (PF)) in a karst region of southwest China. Abundance of AM fungi and nitrogen-fixing bacteria, plant species diversity, and soil nutrient levels increased from the tussock to the primary forest. The AM fungus, nitrogen-fixing bacterium, and plant community composition differed significantly between vegetation types (p fungi and nitrogen-fixing bacteria, respectively. Available phosphorus, total nitrogen, and soil organic carbon levels and plant richness were positively correlated with the abundance of AM fungi and nitrogen-fixing bacteria (p fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration.

  19. Regional-scale airborne electromagnetic surveying of the Yucatan karst aquifer (Mexico): geological and hydrogeological interpretation

    DEFF Research Database (Denmark)

    Gondwe, Bibi Ruth Neuman; Ottowitz, David; Supper, Robert

    2012-01-01

    -spectral remote sensing imagery, shuttle radar topography data and frequency-domain airborne electromagnetic (AEM) survey data were used to map karst-aquifer structure on the Yucatan Peninsula, Mexico. Anomalous AEM responses correlated with topographic features and anomalous spectral reflectance of the terrain...... as ejecta from the Chicxulub impact (Cretaceous/Paleogene boundary), based on similar resistivity signatures found in borehole logs. Due to limited sensitivity of the AEM survey, the subsurface configuration beneath the low-resistivity layer could not be unambiguously determined. AEM measurements combined...

  20. Liming effects on the chemical composition of the organic surface layer of a mature Norway spruce stand (Picea abies [L.] Karst.)

    NARCIS (Netherlands)

    Rosenberg, W.; Nierop, K.G.J.; Knicker, H.; Jager, de P.A.; Kreutzer, K.; Weiá, T.

    2003-01-01

    The application of lime in a mature Norway spruce (Picea abies [L.] Karst.) forest in southern Germany induced major changes in the activity of soil organisms and root growth. Since this may influence the chemical compostion of the soil organic matter (SOM) of the organic surface layer, its

  1. Stormwater infiltration and the 'urban karst' - A review

    Science.gov (United States)

    Bonneau, Jeremie; Fletcher, Tim D.; Costelloe, Justin F.; Burns, Matthew J.

    2017-09-01

    The covering of native soils with impervious surfaces (e.g. roofs, roads, and pavement) prevents infiltration of rainfall into the ground, resulting in increased surface runoff and decreased groundwater recharge. When this excess water is managed using stormwater drainage systems, flow and water quality regimes of urban streams are severely altered, leading to the degradation of their ecosystems. Urban streams restoration requires alternative approaches towards stormwater management, which aim to restore the flow regime towards pre-development conditions. The practice of stormwater infiltration-achieved using a range of stormwater source-control measures (SCMs)-is central to restoring baseflow. Despite this, little is known about what happens to the infiltrated water. Current knowledge about the impact of stormwater infiltration on flow regimes was reviewed. Infiltration systems were found to be efficient at attenuating high-flow hydrology (reducing peak magnitudes and frequencies) at a range of scales (parcel, streetscape, catchment). Several modelling studies predict a positive impact of stormwater infiltration on baseflow, and empirical evidence is emerging, but the fate of infiltrated stormwater remains unclear. It is not known how infiltrated water travels along the subsurface pathways that characterise the urban environment, in particular the 'urban karst', which results from networks of human-made subsurface pathways, e.g. stormwater and sanitary sewer pipes and associated high permeability trenches. Seepage of groundwater into and around such pipes is possible, meaning some infiltrated stormwater could travel along artificial pathways. The catchment-scale ability of infiltration systems to restore groundwater recharge and baseflow is thus ambiguous. Further understanding of the fate of infiltrated stormwater is required to ensure infiltration systems deliver optimal outcomes for waterway flow regimes.

  2. Potential impacts on regional climate due to land degradation in the Guizhou Karst Plateau of China

    International Nuclear Information System (INIS)

    Gao, Jiangbo; Wu, Shaohong; Xue, Yongkang

    2013-01-01

    The possible regional climatic effects of land condition change in the Guizhou Karst Plateau (GKP), which has experienced serious Karst Rocky Desertification (KRD) in the past decades, were investigated in this study using the Weather Research and Forecasting (WRF) regional climate model. It was shown that when compared with validation datasets, the WRF showed a high ability to downscale NCEP-DOE Reanalysis-2, which provided the initial and lateral boundary conditions for WRF, especially for the precipitation simulation. After land degradation over the GKP, the net radiation and evaporation were reduced mainly within the desertification area, consistent with the reduction in rainfall and the increase in surface temperature there. The southwest monsoon flow from the Bay of Bengal was weakened over the adjacent area to the northeast, influencing the East Asian summer monsoon. Meanwhile, the weaker low-layer anti-cyclone and the stronger horizontal convergence enhanced vertical motion in the southeastern coastal areas. Furthermore, owing to the decreased surface heating in the degradation experiment, the lifting over the GKP and neighboring regions to the east was limited, which resulted in a reduced rainfall within the GKP and strengthened the ascending motion downstream over 114°–122° E. Such circulation differences favored an increase in moisture flux and clouds, thereby causing more precipitation in coastal areas of southeast China. (letter)

  3. Turbidity forecasting at a karst spring using combined machine learning and wavelet multiresolution analysis.

    Science.gov (United States)

    Savary, M.; Massei, N.; Johannet, A.; Dupont, J. P.; Hauchard, E.

    2016-12-01

    25% of the world populations drink water extracted from karst aquifer. The comprehension and the protection of these aquifers appear as crucial due to an increase of drinking water needs. In Normandie(North-West of France), the principal exploited aquifer is the chalk aquifer. The chalk aquifer highly karstified is an important water resource, regionally speaking. Connections between surface and underground waters thanks to karstification imply turbidity that decreases water quality. Both numerous parameters and phenomenons, and the non-linearity of the rainfall/turbidity relation influence the turbidity causing difficulties to model and forecast turbidity peaks. In this context, the Yport pumping well provides half of Le Havreconurbation drinking water supply (236 000 inhabitants). The aim of this work is thus to perform prediction of the turbidity peaks in order to help pumping well managers to decrease the impact of turbidity on water treatment. Database consists in hourly rainfalls coming from six rain gauges located on the alimentation basin since 2009 and hourly turbidity since 1993. Because of the lack of accurate physical description of the karst system and its surface basin, the systemic paradigm is chosen and a black box model: a neural network model is chosen. In a first step, correlation analyses are used to design the original model architecture by identifying the relation between output and input. The following optimization phases bring us four different architectures. These models were experimented to forecast 12h ahead turbidity and threshold surpassing. The first model is a simple multilayer perceptron. The second is a two-branches model designed to better represent the fast (rainfall) and low (evapotranspiration) dynamics. Each kind of model is developed using both a recurrent and feed-forward architecture. This work highlights that feed-forward multilayer perceptron is better to predict turbidity peaks when feed-forward two-branches model is

  4. Neural network based inspection of voids and karst conduits in hydro-electric power station tunnels using GPR

    Science.gov (United States)

    Kilic, Gokhan; Eren, Levent

    2018-04-01

    This paper reports on the fundamental role played by Ground Penetrating Radar (GPR), alongside advanced processing and presentation methods, during the tunnel boring project at a Dam and Hydro-Electric Power Station. It identifies from collected GPR data such issues as incomplete grouting and the presence of karst conduits and voids and provides full details of the procedures adopted. In particular, the application of collected GPR data to the Neural Network (NN) method is discussed.

  5. Hydrochemical constraints between the karst Tabular Middle Atlas Causses and the Saïs basin (Morocco): implications of groundwater circulation

    Science.gov (United States)

    Miche, Hélène; Saracco, Ginette; Mayer, Adriano; Qarqori, Khaoula; Rouai, Mohamed; Dekayir, Abdelilah; Chalikakis, Konstantinos; Emblanch, Christophe

    2018-02-01

    The karst Tabular Middle Atlas Causses reservoir is the main drinking-water supply of Fez-Meknes region (Saïs Basin) in Morocco. Recent analyses showed a decline in associated groundwater chemical quality and increased turbidity. To understand this hydrosystem, four surveys were undertaken during fall and spring, 2009-2011. Hydrogeochemical studies coupled with isotopic analyses (δ18O, δD and 222Rn) showed that the aquifers between the causses (mountains) and the Saïs Basin are of Liassic origin and at the southern extremities are of Triassic origin. Five recharge zones of different altitudes have been defined, including two main mixing zones in the south. Deuterium excess results suggest local recharge, while a plot of δ18O versus δD characterizes a confined aquifer in the eastern sector. 222Rn results reveal areas of rapid exchanges with an upwelling time of less than 2 weeks. A schematic conceptual model is presented to explain the groundwater circulation system and the behavior of this karst system.

  6. Development of fog exposure chambers for field experiments under analytically controlled conditions in order to investigate the effect of hydrogen-peroxide-containing fog on spruces (Picea abies Karst. ). Entwicklung von Benebelungskammern fuer Freilandexperimente unter analytisch kontrollierten Bedingungen zur Untersuchung der Wirkung von wasserstoffperoxidhaltigem Nebel auf Fichten (Picea abies Karst. )

    Energy Technology Data Exchange (ETDEWEB)

    Duelme, W.

    1990-01-12

    This thesis investigated the effect of hydrogen-peroxide-containing fog on spruces (Picea abies Karst.) in a field experiment. Under the influence of hydrogen-peroxide-containing fog, primary needles show an increase in wax contents. This entails reduced water loss through cuticular transpiration and premature aging of needles. The pigment contents of the spruce needles reveal an increase in the contents of xanthophylls and chlorophyll B. Especially the increase in oxygenated carotinoids must be interpreted as an indication of advanced senescence. Regarding phenols, too, changes in the composition of individual classes of substances were established. These point to a shift in biosynthesis in favour of higher phenols. (orig./MG)

  7. Characterization of the porosity distribution in the upper part of the karst Biscayne aquifer using common offset ground penetrating radar, Everglades National Park, Florida

    Science.gov (United States)

    Mount, Gregory J.; Comas, Xavier; Cunningham, Kevin J.

    2014-07-01

    the direct porosity values from the whole-core samples confirms the ability of GPR common offset surveys to provide rapid characterization of porosity variability in the Biscayne aquifer. The common offset survey method has several advantages: (1) improved time efficiency in comparison to other GPR acquisition modes such as common midpoints; and (2) enhanced lateral continuity of porosity estimates, particularly when compared to porosity measurements on 1-D samples such as rock cores. The results also support the presence of areas of low EM wave velocity or high porosity under saturated conditions, causing velocity pull-down areas and apparent sag features in the reflection record. This study shows that GPR can be a useful tool for improving understanding of the petrophysical properties of highly heterogeneous systems such as karst aquifers, and thus may assist with the development of more accurate groundwater flow models, such as those used for restoration efforts in the Everglades.

  8. A preliminary study on the feedback of heat transfer on groundwater flow in a Karst geothermal field

    Science.gov (United States)

    Kong, Y.; Pang, Z.; Hu, S.; Pang, J.; Shao, H.; Kolditz, O.

    2014-12-01

    In deep sedimentary basins, groundwater movement can significantly alter the heat flow pattern. At the same time, heat flux induced temperature change can reversely determine the flow regime through density dependent convection process. In Karst aquifers, the heterogeneity in the carbonate rocks makes the identification of this feedback much more complex. In this work, a preliminary study has been made on this feedback in Xiongxian geothermal field. The Karst aquifer in our site has an average thickness of about 1000 m, and is overlaid by over 400 m of quaternary clay, and subsequently 600 m of Neogene sandstone. Geothermal energy has been exploited in the site for space heating. During the heating period from Nov 15th to Mar 15th every year, hot water was extracted from the aquifer and re-injected after the heat extraction. A detailed temperature logging has been carried out in the field, both before and after the heating period, with the consideration that temperature distribution will be affected by the re-injection of cold water. The vertical distribution of temperature in the cap rock shows a constant positive gradient over depth. The heat flux at different locations has been calculated respectively. It is found to decline from southwest to northeast, with the highest value of 113.9 mW/m2 to the lowest of 80.6 mW/m2. This pattern can be well explained by the tectonic features. More interestingly, two inflection points appear on the temperature profile of the Karst layer, revealing strong influence from the cold re-injection water. Also, a 3℃ temperature difference was observed in the June and October measurement, which is related to the reservoir recovery. Currently, a 3D numerical model is being constructed, using the open-source software OpenGeoSys. Heat transport process is coupled with density dependent flow in a monolithic approach, to simulate both heat conduction and groundwater convection. This model will help to quantify the feedback from heat

  9. Resilience of Groundwater Impacted by Land Use and Climate Change in a Karst Aquifer, South China.

    Science.gov (United States)

    Guo, Fang; Jiang, Guanghui; Polk, Jason S; Huang, Xiufeng; Huang, Siyu

    2015-11-01

    Changes of groundwater flow and quality were investigated in a subtropical karst aquifer to determine the driving mechanism. Decreases in groundwater flow are more distinct in discharge zones than those in recharge and runoff zones. Long-term measurement of the represented regional groundwater outlet reveals that groundwater discharge decrease by nearly 50% during the dry season. The hydrochemistry of groundwater in the runoff and discharge zones is of poorer quality than in the recharge zone. Indications of intensive land resource exploitation and changes in land use patterns were attributed to changes in groundwater conditions since 1990, but the influence of climate change was likely from 2001, because the water temperature exhibited increasing trends at a mean rate of 0.02 °C/yr even though groundwater depth was high in the aquifer. These conclusions imply the need for further groundwater monitoring and reevaluation to understand the resilience of aquifer during urbanization and development.

  10. Wet-dry seasonal and vertical geochemical variations in soil water and their driving forces under different land covers in southwest China karst

    Science.gov (United States)

    Wang, Peng; Hu, Bill X.; Wu, Chuanhao; Xu, Kai

    2017-04-01

    Karst aquifers supply drinking water for 25% of the world's population, and they are, however, vulnerable to climate change. Bimonthly hydrochemical data in karst soil water samples from July 2010 to July 2011 were obtained to reveal the seasonal and vertical geochemical variations in soil water under five vegetation types in Qingmuguan, a small karst catchment in southwest China. Soil water chemistry was dominated by Ca2+, HCO3-, and SO42- because of the dissolution of limestone, dolomite, and gypsum minerals in the strata. The predominant hydrochemical types in soil water were Ca2+-HCO3-, Ca2+-SO42-, and mixed Ca2+-HCO3-SO42-. Ca2+ and HCO3- concentrations ranked in the following order: shrub land > dry land > afforestation farmland > bamboo land > grassland. In warm and wet seasons, the main ion concentrations in soil water from grasslands were low. Na+, K+, Ca2+, Mg2+, HCO3-, SO42-, and Cl- concentrations in soil water from other lands were high. An opposite trend was observed in cold and dry seasons. Marked seasonal variations were observed in Ca2+, HCO3-, and NO3- in soil water from dry land. The main ion concentrations in soil water from bamboo lands decreased as soil depth increased. By contrast, the chemistry of soil water from other lands increased as soil depth increased. Their ions were accumulated in depth. A consistent high and low variation between the main ions in soil water and the contents of carbonate and CO2 was found in the soil. Hydrochemical changes in soil water were regulated by the effects of dilution and soil CO2.

  11. Prediction of daily spring hydrographs for future climatic scenarios based on an integrated numerical modelling approach: Application on a snow-governed semi- arid karst catchment area.

    Science.gov (United States)

    Doummar, J.; Kassem, A.; Gurdak, J. J.

    2017-12-01

    In the framework of a three-year USAID/NSF- funded PEER Science project, flow in a karst system in Lebanon (Assal Spring; discharge 0.2-2.5 m3/s yearly volume of 22-30 Mm3) dominated by snow and semi arid conditions was simulated using an integrated numerical model (Mike She 2016). The calibrated model (Nash-Sutcliffe coefficient of 0.77) is based on high resolution input data (2014-2017) and detailed catchment characterization. The approach is to assess the influence of various model parameters on recharge signals in the different hydrological karst compartments (Atmosphere, unsaturated zone, and saturated zone) based on an integrated numerical model. These parameters include precipitation intensity and magnitude, temperature, snow-melt parameters, in addition to karst specific spatially distributed features such as fast infiltration points, soil properties and thickness, topographical slopes, Epikarst and thickness of unsaturated zone, and hydraulic conductivity among others. Moreover, the model is currently simulated forward using various scenarios for future climate (Global Climate Models GCM; daily downscaled temperature and precipitation time series for Lebanon 2020-2045) in order to depict the flow rates expected in the future and the effect of climate change on hydrographs recession coefficients, discharge maxima and minima, and total spring discharge volume . Additionally, a sensitivity analysis of individual or coupled major parameters allows quantifying their impact on recharge or indirectly on the vulnerability of the system (soil thickness, soil and rock hydraulic conductivity appear to be amongst the highly sensitive parameters). This study particularly unravels the normalized single effect of rain magnitude and intensity, snow, and temperature change on the flow rate (e.g., a change of temperature of 3° on the catchment yields a Residual Mean Square Error RMSE of 0.15 m3/s in the spring discharge and a 16% error in the total annual volume with

  12. GYPSUM DEPOSITS IN THE REPUBLIC OF CROATIA

    Directory of Open Access Journals (Sweden)

    Anto Gabrić

    2002-12-01

    Full Text Available The occurences and deposits of gypsum can be found in big karst poljes (Sinjsko, Vrličko, Petrovo, Kosovo and Kninsko as well as in tectonnically predestined river valleys of Zrmanja, Butišnica and Una. There also appear spatially localized occurences on the island of Vis and in the vicinity of Samobor. Evaporites (gypsum and anhydrite with adjoining overlying clastic rocks (red sandstones, siltites and pelites, carbonate rocks (dolomites and limestones and porous carbonate breccias (Rauhwackes were deposited during the period of Upper Permian. The recent position of the Upper Permian beds is a result of complex tectonic, particularly neotectonic, movements and diapiric displacements. Evaporites were deposited in marginal areas of the epicontinental marine basin, in a period of favourable conditions for the sabkha and playa sedimentation due to the continuous shoreline progradation. The Upper Permian age of these sediments in Dalmatio is proved by the characteristic mineral paragenesis and palinological determinations in elastics rocks, as well as by isotope analyses of sulphure in gypsum. Gypsum is a significant ore mineral resource in building, cement production, as well as in a number of tehnological processes used in chemical industry and elsewhere. According to the recent investigations gypsum is predestined to serve as an ore mineral resource of significant perspectives (the paper is published in Croatian.

  13. Impacts of management and climate change on nitrate leaching in a forested karst area.

    Science.gov (United States)

    Dirnböck, Thomas; Kobler, Johannes; Kraus, David; Grote, Rüdiger; Kiese, Ralf

    2016-01-01

    Forest management and climate change, directly or indirectly, affect drinking water resources, both in terms of quality and quantity. In this study in the Northern Limestone Alps in Austria we have chosen model calculations (LandscapeDNDC) in order to resolve the complex long-term interactions of management and climate change and their effect on nitrogen dynamics, and the consequences for nitrate leaching from forest soils into the karst groundwater. Our study highlights the dominant role of forest management in controlling nitrate leaching. Both clear-cut and shelterwood-cut disrupt the nitrogen cycle to an extent that causes peak concentrations and high fluxes into the seepage water. While this effect is well known, our modelling approach has revealed additional positive as well as negative impacts of the expected climatic changes on nitrate leaching. First, we show that peak nitrate concentrations during post-cutting periods were elevated under all climate scenarios. The maximal effects of climatic changes on nitrate concentration peaks were 20-24 mg L(-1) in 2090 with shelterwood or clear-cut management. Second, climate change significantly decreased the cumulative nitrate losses over full forest rotation periods (by 10-20%). The stronger the expected temperature increase and precipitation decrease (in summer), the lesser were the observed nitrate losses. However, mean annual seepage water nitrate concentrations and cumulative nitrate leaching were higher under continuous forest cover management than with shelterwood-cut and clear-cut systems. Watershed management can thus be adapted to climate change by either reducing peak concentrations or long-term loads of nitrate in the karst groundwater. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Geostatistical Borehole Image-Based Mapping of Karst-Carbonate Aquifer Pores.

    Science.gov (United States)

    Sukop, Michael C; Cunningham, Kevin J

    2016-03-01

    Quantification of the character and spatial distribution of porosity in carbonate aquifers is important as input into computer models used in the calculation of intrinsic permeability and for next-generation, high-resolution groundwater flow simulations. Digital, optical, borehole-wall image data from three closely spaced boreholes in the karst-carbonate Biscayne aquifer in southeastern Florida are used in geostatistical experiments to assess the capabilities of various methods to create realistic two-dimensional models of vuggy megaporosity and matrix-porosity distribution in the limestone that composes the aquifer. When the borehole image data alone were used as the model training image, multiple-point geostatistics failed to detect the known spatial autocorrelation of vuggy megaporosity and matrix porosity among the three boreholes, which were only 10 m apart. Variogram analysis and subsequent Gaussian simulation produced results that showed a realistic conceptualization of horizontal continuity of strata dominated by vuggy megaporosity and matrix porosity among the three boreholes. © 2015, National Ground Water Association.

  15. Bacterial and abiotic decay in waterlogged archaeological Picea abies (L.) Karst studied by confocal Raman imaging and ATR-FTIR spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Nanna Bjerregaard; Gierlinger, Notburga; Thygesen, Lisbeth Garbrecht

    2015-01-01

    Waterlogged archaeological Norway spruce [Picea abies (L.) Karst] poles were studied by means of confocal Raman imaging (CRI) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis to determine lignin and polysaccharide composition and distribution in the cell......, and minor oxidation of the lignin polymer compared to recent reference material. This is evidence for abiotic decay in the course of waterlogging....

  16. Hydrogeochemical characteristics of streams with and without acid mine drainage impacts: A paired catchment study in karst geology, SW China

    Science.gov (United States)

    Sun, Jing; Tang, Changyuan; Wu, Pan; Strosnider, William H. J.; Han, Zhiwei

    2013-11-01

    A paired catchment study was used to assess karst hydrogeochemistry of two streams.Chemistry of streams with and without acid mine drainage (AMD) was very different.The observation was supported by PHREEQC modeling of equilibrium conditions.Ionic fluxes of AMD-impacted water were higher than that of non-AMD-impacted water.The higher ionic fluxes were predominantly controlled by the oxidation of pyrite.

  17. The impact of land use and land cover changes on solute dynamics in seepage water of soil from karst hillslopes of Southwest China

    International Nuclear Information System (INIS)

    Ding Hu; Lang Yunchao; Liu Congqiang

    2011-01-01

    Land use and land cover changes can cause variations in terrestrial energy, water balance and availability of nutrients. To understand the role of vegetation in regulating the hydrochemistry of karst hillslopes, overland flow and soil seepage water from two hillslopes covered with and without vegetation were studied in the Huanjiang Observation and Research Station for Karst Ecosystems, Guangxi, SW China. Dissolved major ions, as well as isotopic compositions of dissolved inorganic C (DIC) were examined. Water from the vegetated control slope had higher solute concentrations (except NO 3 - ) and lower δ 13 C values than water from the disturbed slope. The dynamics of K + and NO 3 - in soil water sampled in time-sequence from the control slope was different from the disturbed slope. Specifically, K + and NO 3 - concentrations of the control slope decreased gradually over time, while K + and NO 3 - concentrations of the disturbed slope increased, and other ionic concentrations increased in both of the slopes.

  18. Chemical indicators of anthropogenic impacts in sediments of the pristine karst lakes.

    Science.gov (United States)

    Mikac, I; Fiket, Z; Terzić, S; Barešić, J; Mikac, N; Ahel, M

    2011-08-01

    The anthropogenic impact on the pristine karst lakes was investigated using combination of specific parameters, including multielemental analysis of major inorganic constituents (Al, K, Fe) and trace metals (Li, Ag, Cd, Sn, Pb, Bi, Cr, Co, Ni, Cu, Zn and Sb), polycyclic aromatic hydrocarbons (PAHs) and anionic surfactants of linear alkylbenzene sulfonate (LAS) type. The study was performed in the Plitvice Lakes National Park, situated in a sparsely populated area of the northwestern Dinarides, central Croatia. Dated cores of recent sediments from the two biggest lakes, Lake Prosce and Lake Kozjak, were analysed for the selected contaminants using highly specific methods, involving inductively coupled plasma mass spectrometry (ICP/MS), gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentration of inorganic constituents reflected primarily the geological background of the area as well as geomorphological and geochemical characteristics of the Plitvice Lakes. Due to the higher terrigenous input, the concentration of all elements was significantly higher in the Lake Prosce. The concentration of toxic metals was relatively low in both lakes, except for Cd (>1 mg kg(-1)) and Pb (up to 40 mg kg(-1)). The vertical profiles of these metals suggested that elevated concentrations of Cd were of natural origin, derived from the erosion of the Jurassic dolomite bedrock, while Pb was predominately of recent anthropogenic origin. A similar distribution pattern, suggesting the same prevailing mechanism of input, was observed for pyrolytic PAHs. The characteristic diagnostic PAH ratios revealed that higher PAHs prevailingly originated from the combustion of biomass and fossil fuels. LAS, which represent highly specific indicators of untreated wastewaters, were found in rather high concentrations in the recent sediment layers (up to 4.7 mg kg(-1)), suggesting that contaminated household and hotel wastewaters reach the

  19. Effect of irrigation pumpage during drought on karst aquifer systems in highly agricultural watersheds: example of the Apalachicola-Chattahoochee-Flint river basin, southeastern USA

    Science.gov (United States)

    Mitra, Subhasis; Srivastava, Puneet; Singh, Sarmistha

    2016-09-01

    In the Apalachicola-Chattahoochee-Flint (ACF) river basin in Alabama, Georgia, and Florida (USA), population growth in the city of Atlanta and increased groundwater withdrawal for irrigation in southwest Georgia are greatly affecting the supply of freshwater to downstream regions. This study was conducted to understand and quantify the effect of irrigation pumpage on the karst Upper Floridan Aquifer and river-aquifer interactions in the lower ACF river basin in southwest Georgia. The groundwater MODular Finite-Element model (MODFE) was used for this study. The effect of two drought years, a moderate and a severe drought year, were simulated. Comparison of the results of the irrigated and non-irrigated scenarios showed that groundwater discharge to streams is a major outflow from the aquifer, and irrigation can cause as much as 10 % change in river-aquifer flux. The results also show that during months with high irrigation (e.g., June 2011), storage loss (34 %), the recharge and discharge from the upper semi-confining unit (30 %), and the river-aquifer flux (31 %) are the major water components contributing towards the impact of irrigation pumpage in the study area. A similar scenario plays out in many river basins throughout the world, especially in basins in which underlying karst aquifers are directly connected to a nearby stream. The study suggests that improved groundwater withdrawal strategies using climate forecasts needs to be developed in such a way that excessive withdrawals during droughts can be reduced to protect streams and river flows.

  20. Tectono-karst depressions in the central-western part of the MehedinTi Mountains (SW Romania

    Directory of Open Access Journals (Sweden)

    Ioan Povara

    2014-03-01

    Full Text Available The horst structure of the Mehedinţi Mountains, bounded to the east by the Mehedinţi Plateau, and to the west by the Cerna Graben, has been leveled by the Râul Şes II karst planation surface, at an altitude of 1250-1030 m. Part of the Mesozoic sedimentary cover, limestones developed in Urgonian facies widely outcrop, overlying the crystalline-granite bedrock. On a system of faults adjacent to the graben, close to the Cerna Valley slope, uvala and mega-sinkhole depressions, with various depths, have been developed. From NNE to SSW they are extended over a distance of 14 km and an area of 10.376 km 2 . Their orientation follows the direction of the faults to which they are related. The entire plateau presents an endorhei c character. There were three different stages of genesis and evolution of the depressions: (1 active valley; (2 Quaternary tectonic hanging of the valley; (3 endorheic evolution. Recent depressions evolved only during the last two stages. The most developed depressions are opened westward, as a consequence of the eastward retreat of the Cerna Valley tectonic slope. The rainfall infiltration water is drained towards east and west, outflowing at the base of tectonic sunken blocks as permanent springs with maximum flow rates of up to 50 l/s.

  1. Recharge estimation in semi-arid karst catchments: Central West Bank, Palestine

    Science.gov (United States)

    Jebreen, Hassan; Wohnlich, Stefan; Wisotzky, Frank; Banning, Andre; Niedermayr, Andrea; Ghanem, Marwan

    2018-03-01

    Knowledge of groundwater recharge constitutes a valuable tool for sustainable management in karst systems. In this respect, a quantitative evaluation of groundwater recharge can be considered a pre-requisite for the optimal operation of groundwater resources systems, particular for semi-arid areas. This paper demonstrates the processes affecting recharge in Palestine aquifers. The Central Western Catchment is one of the main water supply sources in the West Bank. Quantification of potential recharge rates are estimated using chloride mass balance (CMB) and empirical recharge equations over the catchment. The results showing the spatialized recharge rate, which ranges from 111-216 mm/year, representing 19-37% of the long-term mean annual rainfall. Using Water Balance models and climatological data (e. g. solar radiation, monthly temperature, average monthly relative humidity and precipitation), actual evapotranspiration (AET) is estimated. The mean annual actual evapotranspiration was about 66-70% of precipitation.

  2. Responses of soil physical and chemical properties to karst rocky desertification evolution in typical karst valley area

    Science.gov (United States)

    Chen, Fei; Zhou, Dequan; Bai, Xiaoyong; zeng, Cheng; Xiao, Jianyong; Qian, Qinghuan; Luo, Guangjie

    2018-01-01

    In order to reveal the differences of soil physical and chemical properties and their response mechanism to the evolution of KRD. The characteristics of soil physical and chemical properties of different grades of KRD were studied by field sampling method to research different types of KRD in the typical karst valley of southern China. Instead of using space of time, to explore the response and the mechanisms of the soil physical and chemical properties at the different evolution process. The results showed that: (1) There were significant differences in organic matter, pH, total nitrogen, total phosphorus, total potassium, sediment concentration, clay content and AWHC in different levels of KRD environment. However, these indicators are not with increasing desertification degree has been degraded, but improved after a first degradation trends; (2) The correlation analysis showed that soil organic matter, acid, alkali, total nitrogen, total phosphorus, total potassium and clay contents were significantly correlated with other physical and chemical factors. They are the key factors of soil physical and chemical properties, play a key role in improving soil physical and chemical properties and promoting nutrient cycling; (3) The principal component analysis showed that the cumulative contribution rate of organic matter, pH, total nitrogen, total phosphorus, total potassium and sediment concentration was 80.26%, which was the key index to evaluate rocky desertification degree based on soil physical and chemical properties. The results have important theoretical and practical significance for the protection and restoration of rocky desertification ecosystem in southwest China.

  3. Cansiglio Karst Plateau: 10 Years of Geodetic-Hydrological Observations in Seismically Active Northeast Italy

    Science.gov (United States)

    Grillo, Barbara; Braitenberg, Carla; Nagy, Ildikó; Devoti, Roberto; Zuliani, David; Fabris, Paolo

    2018-04-01

    Ten years' geodetic observations (2006-2016) in a natural cave of the Cansiglio Plateau (Bus de la Genziana), a limestone karstic area in northeastern Italy, are discussed. The area is of medium-high seismic risk: a strong earthquake in 1936 below the plateau (M m = 6.2) and the 1976 disastrous Friuli earthquake (M m = 6.5) are recent events. At the foothills of the karstic massif, three springs emerge, with average flow from 5 to 10 m3/s, and which are the sources of a river. The tiltmeter station is set in a natural cavity that is part of a karstic system. From March 2013, a multiparametric logger (temperature, stage, electrical conductivity) was installed in the siphon at the bottom of the cave to discover the underground hydrodynamics. The tilt records include signals induced by hydrologic and tectonic effects. The tiltmeter signals have a clear correlation to the rainfall, the discharge series of the river and the data recorded by multiparametric loggers. Additionally, the data of a permanent GPS station located on the southern slopes of the Cansiglio Massif (CANV) show also a clear correspondence with the river level. The fast water infiltration into the epikarst, closely related to daily rainfall, is distinguished in the tilt records from the characteristic time evolution of the karstic springs, which have an impulsive level increase with successive exponential decay. It demonstrates the usefulness of geodetic measurements to reveal the hydrological response of the karst. One outcome of the work is that the tiltmeters can be used as proxies for the presence of flow channels and the pressure that builds up due to the water flow. With 10 years of data, a new multidisciplinary frontier was opened between the geodetic studies and the karstic hydrogeology to obtain a more complete geologic description of the karst plateau.

  4. Tile drainage as karst: Conduit flow and diffuse flow in a tile-drained watershed

    Science.gov (United States)

    Schilling, K.E.; Helmers, M.

    2008-01-01

    The similarity of tiled-drained watersheds to karst drainage basins can be used to improve understanding of watershed-scale nutrient losses from subsurface tile drainage networks. In this study, short-term variations in discharge and chemistry were examined from a tile outlet collecting subsurface tile flow from a 963 ha agricultural watershed. Study objectives were to apply analytical techniques from karst springs to tile discharge to evaluate water sources and estimate the loads of agricultural pollutants discharged from the tile with conduit, intermediate and diffuse flow regimes. A two-member mixing model using nitrate, chloride and specific conductance was used to distinguish rainwater versus groundwater inputs. Results indicated that groundwater comprised 75% of the discharge for a three-day storm period and rainwater was primarily concentrated during the hydrograph peak. A contrasting pattern of solute concentrations and export loads was observed in tile flow. During base flow periods, tile flow consisted of diffuse flow from groundwater sources and contained elevated levels of nitrate, chloride and specific conductance. During storm events, suspended solids and pollutants adhered to soil surfaces (phosphorus, ammonium and organic nitrogen) were concentrated and discharged during the rapid, conduit flow portion of the hydrograph. During a three-day period, conduit flow occurred for 5.6% of the time but accounted for 16.5% of the total flow. Nitrate and chloride were delivered primarily with diffuse flow (more than 70%), whereas 80-94% of total suspended sediment, phosphorus and ammonium were exported with conduit and intermediate flow regimes. Understanding the water sources contributing to tile drainage and the manner by which pollutant discharge occurs from these systems (conduit, intermediate or diffuse flow) may be useful for designing, implementing and evaluating non-point source reduction strategies in tile-drained landscapes. ?? 2007 Elsevier B.V. All

  5. Applying a weighted random forests method to extract karst sinkholes from LiDAR data

    Science.gov (United States)

    Zhu, Junfeng; Pierskalla, William P.

    2016-02-01

    Detailed mapping of sinkholes provides critical information for mitigating sinkhole hazards and understanding groundwater and surface water interactions in karst terrains. LiDAR (Light Detection and Ranging) measures the earth's surface in high-resolution and high-density and has shown great potentials to drastically improve locating and delineating sinkholes. However, processing LiDAR data to extract sinkholes requires separating sinkholes from other depressions, which can be laborious because of the sheer number of the depressions commonly generated from LiDAR data. In this study, we applied the random forests, a machine learning method, to automatically separate sinkholes from other depressions in a karst region in central Kentucky. The sinkhole-extraction random forest was grown on a training dataset built from an area where LiDAR-derived depressions were manually classified through a visual inspection and field verification process. Based on the geometry of depressions, as well as natural and human factors related to sinkholes, 11 parameters were selected as predictive variables to form the dataset. Because the training dataset was imbalanced with the majority of depressions being non-sinkholes, a weighted random forests method was used to improve the accuracy of predicting sinkholes. The weighted random forest achieved an average accuracy of 89.95% for the training dataset, demonstrating that the random forest can be an effective sinkhole classifier. Testing of the random forest in another area, however, resulted in moderate success with an average accuracy rate of 73.96%. This study suggests that an automatic sinkhole extraction procedure like the random forest classifier can significantly reduce time and labor costs and makes its more tractable to map sinkholes using LiDAR data for large areas. However, the random forests method cannot totally replace manual procedures, such as visual inspection and field verification.

  6. SPELEOTHERAPY DEVELOPMENT IN ROMANIA ON THE WORLD CONTEXT AND PERSPECTIVES FOR USE OF SOME SALT MINES AND KARST CAVES FOR SPELEOTHERAPEUTIC AND BALNEOCLIMATIC TOURISM PURPOSES

    Directory of Open Access Journals (Sweden)

    Simionca Iuri

    2013-09-01

    Full Text Available Speleotherapy (ST is a relatively new method of complementary medicine, although, as is well known ancient tribes appreciated isolation in underwater caves, salt or karst caves, or possessing various ores and was officially recognized in the years 1950-1960 in Germany (K.Spannagel, 1961 and Poland (M. Skulimowski, 1965. Professor Mieczyslaw Skulimowski has granted of speleotherapy in "Wieliczka" Salt Mine, the name of subterraneotherapy, soon to be also called the Skulimowski method. Number of speleotherapeutic centers and speleotherapy symposiums has increased considerably (H.Trimmel, 1994. Speleotherapy in the underground now is an effective therapeutic method for the treatment of obstructive respiratory tract diseases, especially of patients with bronchial asthma (BA, the upward and effective practice in Central and Eastern Europe, but also in the West: Austria, Czech Republic, Germany, Poland, Russia, Slovakia, Ukraine, Belarus, Hungary etc.

  7. Karst connections between unconfined aquifers and the Upper Floridan aquifer in south Georgia: geophysical evidence and hydrogeological models

    Science.gov (United States)

    Thieme, D. M.; Denizman, C.

    2011-12-01

    Buried karst features in sedimentary rocks of the south Georgia Coastal Plain present a challenge for hydrogeological models of recharge and confined flow within the underlying Upper Floridan aquifer. The Withlacoochee River, the trunk stream for the area, frequently disappears into subsurface caverns as it makes its way south to join the Suwannee River in northern Florida. The Withlacoochee also receives inputs from small ponds and bays which in turn receive spring and seep groundwater inputs. We have mapped karst topography at the "top of rock" using ground-penetrating radar (GPR). Up to seven meters of relief is indicated for the paleotopography on Miocene to Pliocene rocks, contrasting with the more subdued relief of the modern landscape. Current stratigraphic and hydrogeological reconstructions do not incorporate this amount of relief or lateral variation in the confining beds. One "pipe" which is approximately four meters in diameter is being mapped in detail. We have field evidence at this location for rapid movement of surficial pond and river water with a meteoric signature through several separate strata of sedimentary rock into an aquifer in the Hawthorn formation. We use our geophysical and hydrological field evidence to constrain quantitative hydrogeological models for the flow rates into and out of both this upper aquifer and the underlying Upper Floridan aquifer, which is generally considered to be confined by the clays of the Hawthorn.

  8. Multi-geophysical approaches to detect karst channels underground - A case study in Mengzi of Yunnan Province, China

    Science.gov (United States)

    Gan, Fuping; Han, Kai; Lan, Funing; Chen, Yuling; Zhang, Wei

    2017-01-01

    Mengzi locates in the south 20 km away from the outlet of Nandong subsurface river, and has been suffering from water deficiency in recent years. It is necessary to find out the water resources underground according to the geological characteristics such as the positions and buried depths of the underground river to improve the civil and industrial environments. Due to the adverse factors such as topographic relief, bare rocks in karst terrains, the geophysical approaches, such as Controlled Source Audio Magnetotellurics and Seismic Refraction Tomography, were used to roughly identify faults and fracture zones by the geophysical features of low resistivity and low velocity, and then used the mise-a-la-masse method to judge which faults and fracture zones should be the potential channels of the subsurface river. Five anomalies were recognized along the profile of 2.4 km long and showed that the northeast river system has several branches. Drilling data have proved that the first borehole indicated a water bearing channel by a characteristics of rock core of river sands and gravels deposition, the second one encountered water-filled fracture zone with abundant water, and the third one exposed mud-filled fracture zone without sustainable water. The results from this case study show that the combination of Controlled Source Audio Magnetotellurics, Seismic Refraction Tomography and mise-a-la-Masse is one of the effective methods to detect water-filled channels or fracture zones in karst terrains.

  9. Hydrogeology of northern Sierra de Chiapas, Mexico: a conceptual model based on a geochemical characterization of sulfide-rich karst brackish springs

    Science.gov (United States)

    Rosales Lagarde, Laura; Boston, Penelope J.; Campbell, Andrew R.; Hose, Louise D.; Axen, Gary; Stafford, Kevin W.

    2014-09-01

    Conspicuous sulfide-rich karst springs flow from Cretaceous carbonates in northern Sierra de Chiapas, Mexico. This is a geologically complex, tropical karst area. The physical, geologic, hydrologic and chemical attributes of these springs were determined and integrated into a conceptual hydrogeologic model. A meteoric source and a recharge elevation below 1,500 m are estimated from the spring-water isotopic signature regardless of their chemical composition. Brackish spring water flows at a maximum depth of 2,000 m, as inferred from similar chemical attributes to the produced water from a nearby oil well. Oil reservoirs may be found at depths below 2,000 m. Three subsurface environments or aquifers are identified based on the B, Li+, K+ and SiO2 concentrations, spring water temperatures, and CO2 pressures. There is mixing between these aquifers. The aquifer designated Local is shallow and contains potable water vulnerable to pollution. The aquifer named Northern receives some brackish produced water. The composition of the Southern aquifer is influenced by halite dissolution enhanced at fault detachment surfaces. Epigenic speleogenesis is associated with the Local springs. In contrast, hypogenic speleogenesis is associated with the brackish sulfidic springs from the Northern and the Southern environments.

  10. The impact of land use and land cover changes on solute dynamics in seepage water of soil from karst hillslopes of Southwest China

    Energy Technology Data Exchange (ETDEWEB)

    Ding Hu; Lang Yunchao [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46th Guanshui Road, Guiyang 550002 (China); Liu Congqiang, E-mail: liucongqiang@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46th Guanshui Road, Guiyang 550002 (China)

    2011-06-15

    Land use and land cover changes can cause variations in terrestrial energy, water balance and availability of nutrients. To understand the role of vegetation in regulating the hydrochemistry of karst hillslopes, overland flow and soil seepage water from two hillslopes covered with and without vegetation were studied in the Huanjiang Observation and Research Station for Karst Ecosystems, Guangxi, SW China. Dissolved major ions, as well as isotopic compositions of dissolved inorganic C (DIC) were examined. Water from the vegetated control slope had higher solute concentrations (except NO{sub 3}{sup -}) and lower {delta}{sup 13}C values than water from the disturbed slope. The dynamics of K{sup +} and NO{sub 3}{sup -} in soil water sampled in time-sequence from the control slope was different from the disturbed slope. Specifically, K{sup +} and NO{sub 3}{sup -} concentrations of the control slope decreased gradually over time, while K{sup +} and NO{sub 3}{sup -} concentrations of the disturbed slope increased, and other ionic concentrations increased in both of the slopes.

  11. Karst system vadose zone hydrodynamics highlighted by an integrative geophysical and hydrogeological monitoring

    Science.gov (United States)

    Watlet, A.; Van Camp, M. J.; Francis, O.; Poulain, A.; Hallet, V.; Rochez, G.; Kaufmann, O.

    2015-12-01

    The vadose zone of karst systems plays an important role on the water dynamics. In particular, temporary perched aquifers can appear in the subsurface due to changes of climate conditions, diminished evapotranspiration and differences of porosity relative to deeper layers. It is therefore crucial, but challenging, to separate the hydrological signature of the vadose zone from the one of the saturated zone for understanding hydrological processes that occur in the vadose zone. Although many difficulties are usually encountered when studying karst environments due to their heterogeneities, cave systems offer an outstanding opportunity to investigate vadose zone from the inside with various techniques. We present results covering two years of hydrogeological and geophysical monitoring at the Rochefort Cave Laboratory (RCL), located in the Variscan fold-and-thrust belt (Belgium), a region that shows many karstic networks within Devonian limestone units. Hydrogeological data such as flows and levels monitoring or tracer tests performed in both vadose and saturated zones bring valuable information on the hydrological context of the studied area. Combining those results with geophysical measurements allows validating and imaging them with more integrative techniques. A microgravimetric monitoring involves a superconducting gravimeter continuously measuring at the surface of the RCL. Early in 2015, a second relative gravimeter was installed in the underlying cave system located 35 meters below the surface. This set up allows highlighting vadose gravity changes. These relative measurements are calibrated using an absolute gravimeter. 12 additional stations (7 at the surface, 5 in the cave) are monitored on a monthly basis by a spring gravimeter. To complete these gravimetric measurements, the site has been equipped with a permanent Electrical Resistivity Tomography (ERT) monitoring system comprising an uncommon array of surface, borehole and cave electrodes. Although such

  12. Cd pollution and ecological risk assessment for mining activity zone in Karst Area

    Science.gov (United States)

    Yang, B.; He, J. L.; Wen, X. M.; Tan, H.

    2017-08-01

    The monitored soil samples were collected from farmland in the area with mining activity in Karst area in Liupanshui. In this article, moss bag technology and TSP were used simultaneously for Cd transportation and deposition in the study area. Geostatistics and GIS were then used for the spatial distribution of Cd in the soil. Afterwards, Cd pollution to the soil environment and human health was studied by using the geo-accumulation index and potential ecological risk index methods. The results indicated that atmospheric deposition is the major route of Cd pollution. A moderate to strong pollution of Cd in the area and the degree of potential ecological risk was in a high level in the study area. Furthermore, Cd pollution in Liupanshui may originate from mining activity and atmospheric deposition.

  13. Linking foliar chemistry to forest floor solid and solution phase organic C and N in Picea ahies [L.) Karst stands in northern Bohemia

    Czech Academy of Sciences Publication Activity Database

    Aitkenhead-Peterson, J. A.; Alexander, J.E.; Albrechtová, J.; Krám, P.; Rock, B.; Cudlín, Pavel; Hruška, J.; Lhotáková, Z.; Huntley, R.; Oulehle, F.; Polák, T.; McDowel, W.H.

    2006-01-01

    Roč. 283, 1-2 (2006), s. 187-201 ISSN 0032-079X R&D Projects: GA MŠk ME 658 Institutional research plan: CEZ:AV0Z60870520 Keywords : cellulose and nitrogen * dissolved organic carbon * dissolved organic nitrogen * forest floor C:N * foliar Iignin, * Picea abies [L.] Karst Subject RIV: GK - Forestry Impact factor: 1.495, year: 2006

  14. Joining direct and indirect inverse calibration methods to characterize karst, coastal aquifers

    Science.gov (United States)

    De Filippis, Giovanna; Foglia, Laura; Giudici, Mauro; Mehl, Steffen; Margiotta, Stefano; Negri, Sergio

    2016-04-01

    Parameter estimation is extremely relevant for accurate simulation of groundwater flow. Parameter values for models of large-scale catchments are usually derived from a limited set of field observations, which can rarely be obtained in a straightforward way from field tests or laboratory measurements on samples, due to a number of factors, including measurement errors and inadequate sampling density. Indeed, a wide gap exists between the local scale, at which most of the observations are taken, and the regional or basin scale, at which the planning and management decisions are usually made. For this reason, the use of geologic information and field data is generally made by zoning the parameter fields. However, pure zoning does not perform well in the case of fairly complex aquifers and this is particularly true for karst aquifers. In fact, the support of the hydraulic conductivity measured in the field is normally much smaller than the cell size of the numerical model, so it should be upscaled to a scale consistent with that of the numerical model discretization. Automatic inverse calibration is a valuable procedure to identify model parameter values by conditioning on observed, available data, limiting the subjective evaluations introduced with the trial-and-error technique. Many approaches have been proposed to solve the inverse problem. Generally speaking, inverse methods fall into two groups: direct and indirect methods. Direct methods allow determination of hydraulic conductivities from the groundwater flow equations which relate the conductivity and head fields. Indirect methods, instead, can handle any type of parameters, independently from the mathematical equations that govern the process, and condition parameter values and model construction on measurements of model output quantities, compared with the available observation data, through the minimization of an objective function. Both approaches have pros and cons, depending also on model complexity. For

  15. Clay-mineral assemblages from some levels of K-118 drill core of Maha Sarakham evaporites, northeastern Thailand

    Science.gov (United States)

    Suwanich, Parkorn

    Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate MgAl atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.

  16. Calcium content and high calcium adaptation of plants in karst areas of southwestern Hunan, China

    Science.gov (United States)

    Wei, Xiaocong; Deng, Xiangwen; Xiang, Wenhua; Lei, Pifeng; Ouyang, Shuai; Wen, Hongfang; Chen, Liang

    2018-05-01

    Rocky desertification is a major ecological problem of land degradation in karst areas. In these areas, the high soil calcium (Ca) content has become an important environmental factor that can affect the restoration of vegetation. Consequently, the screening of plant species that can adapt to high Ca soil environments is a critical step in vegetation restoration. In this study, three grades of rocky desertification sample areas were selected in karst areas of southwestern Hunan, China (LRD: light rocky desertification; MRD: moderate rocky desertification; and IRD: intense rocky desertification). Each grade of these sample areas had three sample plots in different slope positions, each of which had four small quadrats (one in rocky-side areas, three in non-rocky-side areas). We measured the Ca content of leaves, branches, and roots from 41 plant species, as well as soil total Ca (TCa) and exchangeable Ca (ECa) at depths of 0-15, 15-30, and 30-45 cm in each small quadrat. The results showed that the soil Ca2+ content in rocky-side areas was significantly higher than that in non-rocky-side areas (p desertification, in the order IRD > MRD > LRD. For all plant functional groups, the plant Ca content of aboveground parts was significantly higher than that of the belowground parts (p 1). The differences in Ca2+ content between the aboveground and belowground parts of the 17 dominant species were calculated, and their correlations with soil ECa content were analyzed. The results showed that these 17 species can be divided into three categories: Ca-indifferent plants, high-Ca plants, and low-Ca plants. These findings provide a vital theoretical basis and practical guide for vegetation restoration and ecosystem reconstruction in rocky desertification areas.

  17. Morphometric variation in the papionin muzzle and the biochronology of the South African Plio-Pleistocene karst cave deposits.

    Science.gov (United States)

    Gilbert, Christopher C; Grine, Frederick E

    2010-03-01

    Papionin monkeys are widespread, relatively common members of Plio-Pleistocene faunal assemblages across Africa. For these reasons, papionin taxa have been used as biochronological indicators by which to infer the ages of the South African karst cave deposits. A recent morphometric study of South African fossil papionin muzzle shape concluded that its variation attests to a substantial and greater time depth for these sites than is generally estimated. This inference is significant, because accurate dating of the South African cave sites is critical to our knowledge of hominin evolution and mammalian biogeographic history. We here report the results of a comparative analysis of extant papionin monkeys by which variability of the South African fossil papionins may be assessed. The muzzles of 106 specimens representing six extant papionin genera were digitized and interlandmark distances were calculated. Results demonstrate that the overall amount of morphological variation present within the fossil assemblage fits comfortably within the range exhibited by the extant sample. We also performed a statistical experiment to assess the limitations imposed by small sample sizes, such as typically encountered in the fossil record. Results suggest that 15 specimens are sufficient to accurately represent the population mean for a given phenotype, but small sample sizes are insufficient to permit the accurate estimation of the population standard deviation, variance, and range. The suggestion that the muzzle morphology of fossil papionins attests to a considerable and previously unrecognized temporal depth of the South African karst cave sites is unwarranted.

  18. Structural and lithological conditioning of the large karst systems of the Sierra de los Organos, Pinar del Rio, Cuba; Condicionantes estructurales y litologicas de los grandes sistemas karsticos de la Sierra de los Organos, Pinar del Rio, Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Guanche, C.; Ramirez Hernandez, R.; Farfan Gonzalez, H.; Estevez Cruz, E.; Ordaz Hernandez, A.; Aldana Vilas, C.

    2016-07-01

    he karst, a complex phenomenon, is governed by a number of variables which dictate its genesis and evolution. Among these variables tectonic settings and lithology play the main role. In Cuba, approximately 65% of the territory is occupied by karst. The Sierra de los Organos, part of Cordillera de Guaniguanico, has some of the largest karstic systems in the country. With the aim of demonstrating the relationship between the spatial and morphological development of the underground karstic systems and the geological structure and lithology of the area, several structural and morphological measurements and field observations have been made. These measurements and observations allowing us to conclude that the karstic processes take place mainly in massive, relatively homogeneous and very thick limestone in the Sierra de los Organos. Moreover, these rocks are characterized by both low porosity and a high degree of fracturing. These karstic forms are also conditioned by the existence of various fracturing systems with general NE-SW and NW-SE orientations. Interception of these fracturing systems provides, as expected, areas with the largest volumes of karstic cavities. (Author)

  19. Dynamic properties of anhydrites, marls and salts of the Gachsaran evaporitic formation, Iran

    International Nuclear Information System (INIS)

    Gorjian, M; Memarian, H; Moosavi, M; Mehrgini, B

    2013-01-01

    A large carbonate oil field in Iran is suffering from severe casing collapses and related operational problems in anhydrite, marl and salt sequences of the Gachsaran cap rock formation. To investigate the causes and cures of operational problems, specifically casing collapse, knowing geomechanical properties of anhydrite, marl and salt of this formation is a prerequisite. However, taking cores in this formation is virtually impossible due to high solubility and weakness of the rocks. Moreover, there are insufficient well log data in this formation and the only available running well log is V p . In this paper, in order to obtain the dynamic parameters of the Gachsaran formation, V p , V s and ρ b in anhydrite, marl and salt cores, which had been taken from depths up to 300 m, were measured. Moreover, V p and V s in salt cores under different triaxial and hydrostatic stress conditions were obtained. The V p –V s, (V p /V s )–V p and V p –ρ b relations in anhydrite, marl and salt were investigated. The established relations in these anhydrite samples were verified by the data derived from limited cores which were taken from 3600 m depth. The relations between dynamic properties of salt with lateral and hydrostatic stresses were investigated. In conclusion, V s , ρ b and the ratio of V p /V s in anhydrite and marl can be estimated through the established relations and having V p logs in the Gachsaran formation. As a result, the dynamic properties of these rocks can be calculated in different depths of this evaporitic formation. Furthermore, the dynamic properties of salt rock seem to be constant in various depths and under differing triaxial and hydrostatic stress conditions. (paper)

  20. Nitrogen Source Inventory and Loading Tool: An integrated approach toward restoration of water-quality impaired karst springs.

    Science.gov (United States)

    Eller, Kirstin T; Katz, Brian G

    2017-07-01

    Nitrogen (N) from anthropogenic sources has contaminated groundwater used as drinking water in addition to impairing water quality and ecosystem health of karst springs. The Nitrogen Source Inventory and Loading Tool (NSILT) was developed as an ArcGIS and spreadsheet-based approach that provides spatial estimates of current nitrogen (N) inputs to the land surface and loads to groundwater from nonpoint and point sources within the groundwater contributing area. The NSILT involves a three-step approach where local and regional land use practices and N sources are evaluated to: (1) estimate N input to the land surface, (2) quantify subsurface environmental attenuation, and (3) assess regional recharge to the aquifer. NSILT was used to assess nitrogen loading to groundwater in two karst spring areas in west-central Florida: Rainbow Springs (RS) and Kings Bay (KB). The karstic Upper Floridan aquifer (UFA) is the source of water discharging to the springs in both areas. In the KB study area (predominantly urban land use), septic systems and urban fertilizers contribute 48% and 22%, respectively, of the estimated total annual N load to groundwater 294,400 kg-N/yr. In contrast for the RS study area (predominantly agricultural land use), livestock operations and crop fertilizers contribute 50% and 13%, respectively, of the estimated N load to groundwater. Using overall groundwater N loading rates for the KB and RS study areas, 4.4 and 3.3 kg N/ha, respectively, and spatial recharge rates, the calculated groundwater nitrate-N concentration (2.1 mg/L) agreed closely with the median nitrate-N concentration (1.7 mg/L) from groundwater samples in agricultural land use areas in the RS study area for the period 2010-2014. NSILT results provide critical information for prioritizing and designing restoration efforts for water-quality impaired springs and spring runs affected by multiple sources of nitrogen loading to groundwater. The calculated groundwater N concentration for