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Sample records for groundwater potential zone

  1. Assessment of groundwater recharge potential zone using GIS approach in Purworejo regency, Central Java province, Indonesia

    Science.gov (United States)

    Aryanto, Daniel Eko; Hardiman, Gagoek

    2018-02-01

    Floods and droughts in Purworejo regency are an indication of problems in groundwater management. The current development progress has led to land conversion which has an impact on the problem of water infiltration in Purworejo regency. This study aims to determine the distribution of groundwater recharge potential zones by using geographic information system as the basis for ground water management. The groundwater recharge potential zone is obtained by overlaying all the thematic maps that affect the groundwater infiltration. Each thematic map is weighted according to its effect on groundwater infiltration such as land-use - 25%, rainfall - 20%, litology - 20%, soil - 15%, slope - 10%, lineament - 5%, and river density - 5% to find groundwater recharge potential zones. The groundwater recharge potential zones thus obtained were divided into five categories, viz., very high, high, medium, low and very low zones. The results of this study may be useful for better groundwater planning and management.

  2. Groundwater Potential

    African Journals Online (AJOL)

    big timmy

    4Department of Geology, Ekiti State University, Ado-Ekiti, Nigeria. Corresponding ... integrated for the classification of the study area into different groundwater potential zones. .... table is mainly controlled by subsurface movement of water into ...

  3. Integrated approach for identification of potential groundwater zones ...

    Indian Academy of Sciences (India)

    The population density of the area is 370 person per sq. km. .... The depth of bore wells on average ranges from 40 to 80m with a ..... draw down pumping test which showed optimum yield of ... izontally stratified earth; Geophysical Prospecting 19. 769–775. ... groundwater potential of India – an estimate based on injected ...

  4. Mapping of groundwater potential zones in the musi basin using remote sensing data and gis

    NARCIS (Netherlands)

    Ganapuram, Sreedhar; Vijaya Kumar, G.T.; Murali Krishna, I.V.; Kahya, Ercan; Demirel, M.C.

    2009-01-01

    The objective of this study is to explore the groundwater availability for agriculture in the Musi basin. Remote sensing data and geographic information system were used to locate potential zones for groundwater in the Musi basin. Various maps (i.e., base, hydrogeomorphological, geological,

  5. Delineation of groundwater potential zone: An AHP/ANP approach

    Indian Academy of Sciences (India)

    Groundwater; multi-criteria decision making; analytical network process. J. Earth Syst. ... than AHP for decision making. ... the themes and provide utility weights for the alter- natives ... theory that has been applied to classifying ETM+ image.

  6. Deciphering groundwater potential zones in hard rock terrain using geospatial technology.

    Science.gov (United States)

    Dar, Imran A; Sankar, K; Dar, Mithas A

    2011-02-01

    Remote sensing and geographical information system (GIS) has become one of the leading tools in the field of groundwater research, which helps in assessing, monitoring, and conserving groundwater resources. This paper mainly deals with the integrated approach of remote sensing and GIS to delineate groundwater potential zones in hard rock terrain. Digitized vector maps pertaining to chosen parameters, viz. geomorphology, geology, land use/land cover, lineament, relief, and drainage, were converted to raster data using 23 m×23 m grid cell size. Moreover, curvature of the study area was also considered while manipulating the spatial data. The raster maps of these parameters were assigned to their respective theme weight and class weights. The individual theme weight was multiplied by its respective class weight and then all the raster thematic layers were aggregated in a linear combination equation in Arc Map GIS Raster Calculator module. Moreover, the weighted layers were statistically modeled to get the areal extent of groundwater prospects with respect to each thematic layer. The final result depicts the favorable prospective zones in the study area and can be helpful in better planning and management of groundwater resources especially in hard rock terrains.

  7. Delineation of groundwater potential zones in Theni district, Tamil Nadu, using remote sensing, GIS and MIF techniques

    Directory of Open Access Journals (Sweden)

    N.S. Magesh

    2012-03-01

    Full Text Available Integration of remote sensing data and the geographical information system (GIS for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing, monitoring, and conserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques. Survey of India toposheets and IRS-1C satellite imageries are used to prepare various thematic layers viz. lithology, slope, land-use, lineament, drainage, soil, and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS. The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor (MIF technique. Moreover, each weighted thematic layer is statistically computed to get the groundwater potential zones. The groundwater potential zones thus obtained were divided into four categories, viz., very poor, poor, good, and very good zones. The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of groundwater resources.

  8. Delineation of groundwater development potential zones in parts of marginal Ganga Alluvial Plain in South Bihar, Eastern India.

    Science.gov (United States)

    Saha, Dipankar; Dhar, Y R; Vittala, S S

    2010-06-01

    A part of the Gangetic Alluvial Plain covering 2,228 km(2), in the state of Bihar, is studied for demarcating groundwater development potential zones. The area is mainly agrarian and experiencing intensive groundwater draft to the tune of 0.12 million cubic metre per square kilometres per year from the Quaternary marginal alluvial deposits, unconformably overlain northerly sloping Precambrian bedrock. Multiparametric data on groundwater comprising water level, hydraulic gradient (pre- and post-monsoon), aquifer thickness, permeability, suitability of groundwater for drinking and irrigation and groundwater resources vs. draft are spatially analysed and integrated on a Geographical Information System platform to generate thematic layers. By integrating these layers, three zones have been delineated based on groundwater development potential. It is inferred that about 48% of the area covering northern part has high development potential, while medium and low development potential category covers 41% of the area. Further increase in groundwater extraction is not recommended for an area of 173 km(2), affected by over-exploitation. The replenishable groundwater resource available for further extraction has been estimated. The development potential enhances towards north with increase in thickness of sediments. Local deviations are due to variation of-(1) cumulative thickness of aquifers, (2) deeper water level resulting from localised heavy groundwater extraction and (3) aquifer permeability.

  9. Mapping of groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India, using remote sensing and GIS techniques.

    Science.gov (United States)

    Thilagavathi, N; Subramani, T; Suresh, M; Karunanidhi, D

    2015-04-01

    This study proposes to introduce the remote sensing and geographic information system (GIS) techniques in mapping the groundwater potential zones. Remote sensing and GIS techniques have been used to map the groundwater potential zones in Salem Chalk Hills, Tamil Nadu, India. Charnockites and fissile hornblende biotite gneiss are the major rock types in this region. Dunites and peridodites are the ultramafic rocks which cut across the foliation planes of the gneisses and are highly weathered. It comprises magnesite and chromite deposits which are excavated by five mining companies by adopting bench mining. The thickness of weathered and fracture zone varies from 2.2 to 50 m in gneissic formation and 5.8 to 55 m in charnockite. At the contacts of gneiss and charnockite, the thickness ranges from 9.0 to 90.8 m favoring good groundwater potential. The mine lease area is underlined by fractured and sheared hornblende biotite gneiss where groundwater potential is good. Water catchment tanks in this area of 5 km radius are small to moderate in size and are only seasonal. They remain dry during summer seasons. As perennial water resources are remote, the domestic and agricultural activities in this region depend mainly upon the groundwater resources. The mines are located in gently slope area, and accumulation of water is not observed except in mine pits even during the monsoon period. Therefore, it is essential to map the groundwater potential zones for proper management of the aquifer system. Satellite imageries were also used to extract lineaments, hydrogeomorphic landforms, drainage patterns, and land use, which are the major controlling factors for the occurrence of groundwater. Various thematic layers pertaining to groundwater existence such as geology, geomorphology, land use/land cover, lineament, lineament density, drainage, drainage density, slope, and soil were generated using GIS tools. By integrating all the above thematic layers based on the ranks and

  10. Integrating geospatial and ground geophysical information as guidelines for groundwater potential zones in hard rock terrains of south India.

    Science.gov (United States)

    Rashid, Mehnaz; Lone, Mahjoor Ahmad; Ahmed, Shakeel

    2012-08-01

    The increasing demand of water has brought tremendous pressure on groundwater resources in the regions were groundwater is prime source of water. The objective of this study was to explore groundwater potential zones in Maheshwaram watershed of Andhra Pradesh, India with semi-arid climatic condition and hard rock granitic terrain. GIS-based modelling was used to integrate remote sensing and geophysical data to delineate groundwater potential zones. In the present study, Indian Remote Sensing RESOURCESAT-1, Linear Imaging Self-Scanner (LISS-4) digital data, ASTER digital elevation model and vertical electrical sounding data along with other data sets were analysed to generate various thematic maps, viz., geomorphology, land use/land cover, geology, lineament density, soil, drainage density, slope, aquifer resistivity and aquifer thickness. Based on this integrated approach, the groundwater availability in the watershed was classified into four categories, viz. very good, good, moderate and poor. The results reveal that the modelling assessment method proposed in this study is an effective tool for deciphering groundwater potential zones for proper planning and management of groundwater resources in diverse hydrogeological terrains.

  11. Environmental isotope and geophysical techniques to identify groundwater potential zones in drought prone areas of Amravati District, Maharashtra, India

    International Nuclear Information System (INIS)

    Jacob, Noble

    2017-01-01

    The groundwater potential of Anjangaon village in Amaravati district of Maharashtra is generally poor and the water quality is saline in most of the places. Farmers dig open wells (up to 30 m depth) and drill bore wells (100-150 m depth) for domestic and irrigation purposes. Most of the wells failed and farmers are struggling for fresh water in this region. To evaluate the groundwater recharge and to identify the groundwater potential zones an environmental isotope and geophysical study was carried out. Water samples were collected from rain, springs, open wells, bore wells and detention tanks and measured for environmental isotopes such as "1"8O, "2H and "3H. Isotope results indicate that the groundwater is getting modern component of recharge from the rain as well as from the detention tanks. The percentage contributions from the detention tanks were estimated to be about 40 to 90 %. In the southern part of the Anjagaon village, an electrical resistivity survey of the geological formation was carried out and a groundwater potential zone was delineated at 45m depth. The farmers were asked to drill bore wells at the identified depth. The drilled five bore wells yielded perennial source of good quality water

  12. Using the natural biodegradation potential of shallow soils for in-situ remediation of deep vadose zone and groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Avishai, Lior; Siebner, Hagar; Dahan, Ofer, E-mail: odahan@bgu.ac.il; Ronen, Zeev, E-mail: zeevrone@bgu.ac.il

    2017-02-15

    Highlights: • Integrated in-situ remediation treatment for soil, vadose zone and groundwater. • Turning the topsoil into an efficient bioreactor for perchlorate degradation. • Treating perchlorate leachate from the deep vadose zone in the topsoil. • Zero effluents discharge from the remediation process. - Abstract: In this study, we examined the ability of top soil to degrade perchlorate from infiltrating polluted groundwater under unsaturated conditions. Column experiments designed to simulate typical remediation operation of daily wetting and draining cycles of contaminated water amended with an electron donor. Covering the infiltration area with bentonite ensured anaerobic conditions. The soil remained unsaturated, and redox potential dropped to less than −200 mV. Perchlorate was reduced continuously from ∼1150 mg/L at the inlet to ∼300 mg/L at the outlet in daily cycles. Removal efficiency was between 60 and 84%. No signs of bioclogging were observed during three operation months although occasional iron reduction observed due to excess electron donor. Changes in perchlorate reducing bacteria numbers were inferred from an increased in pcrA gene abundances from ∼10{sup 5} to 10{sup 7} copied per gram at the end of the experiment indicating the growth of perchlorate-reducing bacteria. We proposed that the topsoil may serve as a bioreactor to treat high concentrations of perchlorate from the contaminated groundwater. The treated water that infiltrates from the topsoil through the vadose zone could be used to flush perchlorate from the deep vadose zone into the groundwater where it is retrieved again for treatment in the topsoil.

  13. Using the natural biodegradation potential of shallow soils for in-situ remediation of deep vadose zone and groundwater

    International Nuclear Information System (INIS)

    Avishai, Lior; Siebner, Hagar; Dahan, Ofer; Ronen, Zeev

    2017-01-01

    Highlights: • Integrated in-situ remediation treatment for soil, vadose zone and groundwater. • Turning the topsoil into an efficient bioreactor for perchlorate degradation. • Treating perchlorate leachate from the deep vadose zone in the topsoil. • Zero effluents discharge from the remediation process. - Abstract: In this study, we examined the ability of top soil to degrade perchlorate from infiltrating polluted groundwater under unsaturated conditions. Column experiments designed to simulate typical remediation operation of daily wetting and draining cycles of contaminated water amended with an electron donor. Covering the infiltration area with bentonite ensured anaerobic conditions. The soil remained unsaturated, and redox potential dropped to less than −200 mV. Perchlorate was reduced continuously from ∼1150 mg/L at the inlet to ∼300 mg/L at the outlet in daily cycles. Removal efficiency was between 60 and 84%. No signs of bioclogging were observed during three operation months although occasional iron reduction observed due to excess electron donor. Changes in perchlorate reducing bacteria numbers were inferred from an increased in pcrA gene abundances from ∼10"5 to 10"7 copied per gram at the end of the experiment indicating the growth of perchlorate-reducing bacteria. We proposed that the topsoil may serve as a bioreactor to treat high concentrations of perchlorate from the contaminated groundwater. The treated water that infiltrates from the topsoil through the vadose zone could be used to flush perchlorate from the deep vadose zone into the groundwater where it is retrieved again for treatment in the topsoil.

  14. Using the natural biodegradation potential of shallow soils for in-situ remediation of deep vadose zone and groundwater.

    Science.gov (United States)

    Avishai, Lior; Siebner, Hagar; Dahan, Ofer; Ronen, Zeev

    2017-02-15

    In this study, we examined the ability of top soil to degrade perchlorate from infiltrating polluted groundwater under unsaturated conditions. Column experiments designed to simulate typical remediation operation of daily wetting and draining cycles of contaminated water amended with an electron donor. Covering the infiltration area with bentonite ensured anaerobic conditions. The soil remained unsaturated, and redox potential dropped to less than -200mV. Perchlorate was reduced continuously from ∼1150mg/L at the inlet to ∼300mg/L at the outlet in daily cycles. Removal efficiency was between 60 and 84%. No signs of bioclogging were observed during three operation months although occasional iron reduction observed due to excess electron donor. Changes in perchlorate reducing bacteria numbers were inferred from an increased in pcrA gene abundances from ∼10 5 to 10 7 copied per gram at the end of the experiment indicating the growth of perchlorate-reducing bacteria. We proposed that the topsoil may serve as a bioreactor to treat high concentrations of perchlorate from the contaminated groundwater. The treated water that infiltrates from the topsoil through the vadose zone could be used to flush perchlorate from the deep vadose zone into the groundwater where it is retrieved again for treatment in the topsoil. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Application of a GIS-/remote sensing-based approach for predicting groundwater potential zones using a multi-criteria data mining methodology.

    Science.gov (United States)

    Mogaji, Kehinde Anthony; Lim, Hwee San

    2017-07-01

    This study integrates the application of Dempster-Shafer-driven evidential belief function (DS-EBF) methodology with remote sensing and geographic information system techniques to analyze surface and subsurface data sets for the spatial prediction of groundwater potential in Perak Province, Malaysia. The study used additional data obtained from the records of the groundwater yield rate of approximately 28 bore well locations. The processed surface and subsurface data produced sets of groundwater potential conditioning factors (GPCFs) from which multiple surface hydrologic and subsurface hydrogeologic parameter thematic maps were generated. The bore well location inventories were partitioned randomly into a ratio of 70% (19 wells) for model training to 30% (9 wells) for model testing. Application results of the DS-EBF relationship model algorithms of the surface- and subsurface-based GPCF thematic maps and the bore well locations produced two groundwater potential prediction (GPP) maps based on surface hydrologic and subsurface hydrogeologic characteristics which established that more than 60% of the study area falling within the moderate-high groundwater potential zones and less than 35% falling within the low potential zones. The estimated uncertainty values within the range of 0 to 17% for the predicted potential zones were quantified using the uncertainty algorithm of the model. The validation results of the GPP maps using relative operating characteristic curve method yielded 80 and 68% success rates and 89 and 53% prediction rates for the subsurface hydrogeologic factor (SUHF)- and surface hydrologic factor (SHF)-based GPP maps, respectively. The study results revealed that the SUHF-based GPP map accurately delineated groundwater potential zones better than the SHF-based GPP map. However, significant information on the low degree of uncertainty of the predicted potential zones established the suitability of the two GPP maps for future development of

  16. Assessment of groundwater potential zones using multi-influencing factor (MIF) and GIS: a case study from Birbhum district, West Bengal

    Science.gov (United States)

    Thapa, Raju; Gupta, Srimanta; Guin, Shirshendu; Kaur, Harjeet

    2017-11-01

    Remote sensing and GIS play a vital role in exploration and assessment of groundwater and has wide application in detection, monitoring, assessment, conservation and various other fields of groundwater-related studies. In this research work, delineation of groundwater potential zone in Birbhum district has been carried out. Various thematic layers viz. geology, geomorphology, soil type, elevation, lineament and fault density, slope, drainage density, land use/land cover, soil texture, and rainfall are digitized and transformed into raster data in ArcGIS 10.3 environment as input factors. Thereafter, multi-influencing factor (MIF) technique is employed where ranks and weights, assigned to each factor are computed statistically. Finally, groundwater potential zones are classified into four categories namely low, medium, high and very high zone. It is observed that 18.41% (836.86 km2) and 34.41% (1563.98 km2) of the study area falls under `low' and `medium' groundwater potential zone, respectively. Approximately 1601.19 km2 area accounting for 35.23% of the study area falls under `high' category and `very high' groundwater potential zone encompasses an area of 542.98 km2 accounting for 11.95% of the total study area. Finally, the model generated groundwater potential zones are validated with reported potential yield data of various wells in the study area. Success and prediction rate curve reveals an accuracy achievement of 83.03 and 78%, respectively. The outcome of the present research work will help the local authorities, researchers, decision makers and planners in formulating better planning and management of groundwater resources in the study area in future perspectives.

  17. Groundwater Capture Zones

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Source water protection areas are delineated for each groundwater-based public water supply system using available geologic and hydrogeologic information to...

  18. Mapping potential zones for groundwater recharge and its evaluation in arid environments using a GIS approach: Case study of North Gafsa Basin (Central Tunisia)

    Science.gov (United States)

    Mokadem, Naziha; Boughariou, Emna; Mudarra, Matías; Ben Brahim, Fatma; Andreo, Bartolome; Hamed, Younes; Bouri, Salem

    2018-05-01

    With the progressive evolution of industrial sector, agricultural, urbanization, population and drinking water supply, the water demand continuously increases which necessitates the planning of groundwater recharge particularly in arid and semi-arid regions. This paper gives a comprehensive review of various recharges studies in the North Gafsa basin (South Tunisia). This latter is characterized by a natural groundwater recharge that is deeply affected by the lack of precipitations. The aim of this study is to determine the recharge potential zones and to quantify (or estimate) the rainfall recharge of the shallow aquifers. The mapping of the potential recharge zones was established in North Gafsa basin, using geological and hydrological parameters such as slope, lithology, topography and stream network. Indeed, GIS provide tools to reclassify these input layers to produce the final map of groundwater potential zones of the study area. The final output map reveals two distinct zones representing moderate and low groundwater potential recharge. Recharge estimations were based on the four methods: (1) Chloride Method, (2) ERAS Method, (3) DGRE coefficient and (4) Fersi equations. Therefore, the overall results of the different methods demonstrate that the use of the DGRE method applying on the potential zones is more validated.

  19. ZONASI POTENSI PENCEMARAN AIR TANAH PADA TERAS SUNGAI CODE YOGYAKARTA (Zoning The Potential Groundwater Pollution at Code River Terrace, Yogyakarta

    Directory of Open Access Journals (Sweden)

    Frista Yorhanita

    2001-08-01

    Full Text Available ABSTRAK Tujuan penelitian ini ialah untuk membuktikan bahwa biomassa Fusarium sp dapat mereduksi Cr(VI, dan biomassa Aspergillus niger dapat digunakan untuk mengambil ion krom dari larutan. Fusarium.sp ditumbuhkan pada media cair kentang dekftosa cair, ditambah K2Cr2O7 atau sludge limbah penyamakan kulit. Selanjutnya diamati perubahan warnanya, bila terjadi perubahan warna dan oranye ke ungu atau tak berwarna maka telah terjadi reduksi krom valensi VI menjadi krom valensi Ill. Aspergillus niger ditumbuhkan pada media Potato dectrose agar (PDA padat, dipindahkan ke media cair yang bensi bakto pepton, bakto dektrose dan srukronutrien. Produksi biomassa dilakukan pada labu erlenmeyer; setelah 5 hari dipanen dan dibuat bubuk. Bubuk ini digunakan untuk mengambil krom dari larutan. Hasil penelitian menunjukkan bahwa biomassa Fusarium sp dapat digunakan untuk mengambil krom dan larutan yang.mengandung KrCrrO, atau sludge limbah penyamakan kulit. Waktu inkubasi yang lebih lama meningkatkan absorbsi krom oleh biomassa Fascrium sp. Fusarium sp mampu mereduksi Cr(VI menjadi Cr(Iii. Biomassa Aspergillus niger dapat digunakan untuk mengambil krom dari larutan. Hasil terbaik diperoleh pada konsentrasi awal 100 mg/I, pada pH 2,0, berat biomassa 0,1 g, dan waktu kontak 12 jam, yaitu 96,23% untuk Cr(II| dan96,3 % untuk Cr(VI. Fusarium sp. dan A. niger dapat digunakan sebagai bioremediator dalam penanganan limbah penyamakan kulit secara biologi.   ABSTRACT The study area of this research was parts of the code river terraces, Yogyakarta. The aims of this research were as follows: (1 to determine the part of the code river terrace which has potential groundwater pollution; (2 to assess the natural physical factors (aquifer materials, depth of groundwater table, and the groundwater flow distance and the non-natural physical factors of environmental sanitation (houses density, population density, horizontal distance between pollution source and well, and the number

  20. Use of geospatial technology for delineating groundwater potential zones with an emphasis on water-table analysis in Dwarka River basin, Birbhum, India

    Science.gov (United States)

    Thapa, Raju; Gupta, Srimanta; Gupta, Arindam; Reddy, D. V.; Kaur, Harjeet

    2018-05-01

    Dwarka River basin in Birbhum, West Bengal (India), is an agriculture-dominated area where groundwater plays a crucial role. The basin experiences seasonal water stress conditions with a scarcity of surface water. In the presented study, delineation of groundwater potential zones (GWPZs) is carried out using a geospatial multi-influencing factor technique. Geology, geomorphology, soil type, land use/land cover, rainfall, lineament and fault density, drainage density, slope, and elevation of the study area were considered for the delineation of GWPZs in the study area. About 9.3, 71.9 and 18.8% of the study area falls within good, moderate and poor groundwater potential zones, respectively. The potential groundwater yield data corroborate the outcome of the model, with maximum yield in the older floodplain and minimum yield in the hard-rock terrains in the western and south-western regions. Validation of the GWPZs using the yield of 148 wells shows very high accuracy of the model prediction, i.e., 89.1% on superimposition and 85.1 and 81.3% on success and prediction rates, respectively. Measurement of the seasonal water-table fluctuation with a multiplicative model of time series for predicting the short-term trend of the water table, followed by chi-square analysis between the predicted and observed water-table depth, indicates a trend of falling groundwater levels, with a 5% level of significance and a p-value of 0.233. The rainfall pattern for the last 3 years of the study shows a moderately positive correlation ( R 2 = 0.308) with the average water-table depth in the study area.

  1. Identification of groundwater potential zones in the Machuca River in the Central Pacific of Costa Rica using a GIS-Multi-criteria analysis

    Science.gov (United States)

    Bonilla, J. P.; Stefan, C.

    2015-12-01

    Water supply systems in the Machuca River basin in the Central Pacific of Costa Rica are subject to fluctuations in their production capacity at the end of the dry season; especially in the lower part of the basin. The urban development - and water demand -- is expected to increase because of a newly build highway. In order to understand the actual water resources and to asses new ones, the identification of groundwater potential zones is done using a geographical information system (GIS) based on thematic raster using fixed score and weight computed by the multi influencing factor (MIF) technique. The thematic layers used in the analysis are lithology, slope, land-use, lineament, drainage, soil and rainfall. The results were compared with the results of the Modified Thornthwaite-Mather model used to perform the water balance on a monthly scale. The groundwater potential was divided into three categories: no suitable, suitable, and very suitable zones. The resulting map is a decision support tool for the planning and management of groundwater resources in the Machuca River basin.

  2. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

    International Nuclear Information System (INIS)

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    g kg -1 , representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO 3 - concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 μg kg -1 a -1 suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H + -amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  3. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

    Science.gov (United States)

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO3- source concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 μg kg−1 a−1 suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H+-amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  4. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Christopher T., E-mail: cmills@usgs.gov [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States); Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J. [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States)

    2011-08-15

    from 0 to 42 {mu}g kg{sup -1}, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO{sub 3}{sup -} concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 {mu}g kg{sup -1} a{sup -1} suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H{sup +}-amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  5. Potential for ground-water contamination from movement of wastewater through the unsaturated zone, upper Mojave River Basin, California

    Science.gov (United States)

    Umari, A.M.; Martin, P.M.; Schroeder, R.A.; Duell, L.F.; Fay, R.G.

    1993-01-01

    Septic-tank wastewater disposed in 30-foot-deep seepage pits (dry wells) at 46,000 residences is estimated to equal 18 percent of the natural recharge to the sole-source aquifer in the rapidly developing upper Mojave River Basin (Victor Valley) in the high desert northeast of Los Angeles. Vertical rates of movement of the wastewater wetting front through the unsaturated zone at three newly occupied residences ranged from 0.07 to 1.0 foot per day. These rates translate to traveltimes of several months to several years for the wastewater wetting front to reach the water table and imply that wastewater from many disposal systems already has reached the water table, which averages about 150 feet below land surface in the Victor Valley. As wastewater percolates from seepage pits into the adjacent unsaturated zone, the nitrogen present in reduced form is rapidly converted to nitrate. Analyses on soil-core extracts and soil moisturefrom suction lysimeters installed beneath the seepage pits at eight residences showed that nitrate concentrations and nitrate/ chloride ratios generally become lower with increasing depth. The intervals of greatest decline seemed to coincide with finer soil texture or were near the water table. Nitrate-reducing bacteria were tested for and found to be present in soil cores from two residences. Sparse nitrogen-15 data from suction lysimeters at one of these residences, where thenitrate concentration decreased by about one-half at a depth of 200 feet, indicate that the nitrate decline was accompanied by nitrogen-15 enrichment in the residual nitrate with an isotope-separation factor of about -10 permil. Despite the potential input of abundant nitrogen with the domestic wastewater recharge, nitrate concentrations in the area's ground water are generally low. The absence of high nitrate concentrations in the ground water is consistent with the existence of denitrification, a microbial nitrogen-removal mechanism, as wastewater moves through the

  6. Hydrogeological Investigation and Groundwater Potential ...

    African Journals Online (AJOL)

    The paper assesses groundwater quality and productivity in Haromaya watershed, eastern. Ethiopia. ... zones, quantity and quality of plant and animal life (Tamire H., 1981). Steep to very ... Present research work was proposed to conduct hydrogeological investigation and assess ...... Water Balance of Haromaya basin,.

  7. Delineation of a wellhead protection zone and determination of flowpaths from potential groundwater contaminant source areas at Camp Ripley, Little Falls, Minnesota.

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, J. J.; Environmental Science Division

    2006-12-22

    Groundwater at Camp Ripley, Minnesota, is recharged both on post and off site and discharged to rivers, wetlands, and pumping wells. The subsurface geologic materials have a wide range of permeabilities and are arranged in a complex fashion as a result of the region's multiple glacial advances. Correlation of individual glacial geologic units is difficult, even between nearby boreholes, because of the heterogeneities in the subsurface. This report documents the creation of a numerical model of groundwater flow for Camp Ripley and hydrologically related areas to the west and southwest. The model relies on a hydrogeological conceptual model built on the findings of a University of Minnesota-Duluth drilling and sampling program conducted in 2001. Because of the site's stratigraphic complexity, a geostatistical approach was taken to handle the uncertainty of the subsurface correlation. The U.S. Geological Survey's MODFLOW code was used to create the steady-state model, which includes input data from a variety of sources and is calibrated to water levels in monitoring wells across much of the site. This model was used for several applications. Wellhead protection zones were delineated for on-site production wells H, L, and N. The zones were determined on the basis of a probabilistic assessment of the groundwater captured by these wells; the assessment, in turn, had been based on multiple realizations of the study area's stratigraphy and groundwater flowfield. An additional application of the model was for estimating flowpaths and times of travel for groundwater at Camp Ripley's range areas and waste management facilities.

  8. Very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) investigation for groundwater potential evaluation in a complex geological terrain around the Ijebu-Ode transition zone, southwestern Nigeria

    International Nuclear Information System (INIS)

    Osinowo, Olawale O; Olayinka, A Idowu

    2012-01-01

    Groundwater exploration in either a basement or sedimentary environment is often fairly well defined and focuses on delineating weathered/fractured rocks or saturated formations, respectively. Conversely, unique geological structures, the complex coexistence of different rock types and poorly defined basal/lateral contacts between basement and sedimentary rocks make groundwater development in a geological transition environment very challenging. Ijebu-Ode and its environs lie within such a problematic transition zone, between the Precambrian basement rocks and Cretaceous sediments of the Dahomey Basin, in southwestern Nigeria, where associated acute groundwater development challenges require adequate subsurface information to maximize its groundwater resource potential. This study integrated very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) geophysical prospecting techniques for a detailed terrain study of Ijebu-Ode in order to establish the reasons for the low groundwater resource potential in the area. Thirty five VLF-EM profiles, 140 vertical electrical soundings (VES) and relevant hydrogeological data were acquired along grids and profiles. Data were filtered, inverted and enhanced using appropriate software packages. The current density and geoelectric parameters of the VLF-EM and VES data were employed to generate terrain maps, the conductivity distribution and a subsurface basement model of the study area. Current density plots and geoelectric parameters identified up to three layers in the basement complex terrain which comprised lateritic topsoil, weathered basement and fresh basement rocks. The five layers encountered in the sedimentary terrain were topsoil, a lateritic unit, a dry sandy unit, a saturated sandy unit and fresh basement rocks. The hydraulic conductivity of the thick (3–18 m) lateritic unit was determined to be 1.32 × 10 −5 mm s −1 , while that of the underlying sandy units ranged from 2.65 × 10 −4 to 1

  9. Numerical modeling for saturated-zone groundwater travel time analysis at Yucca Mountain

    International Nuclear Information System (INIS)

    Arnold, B.W.; Barr, G.E.

    1996-01-01

    A three-dimensional, site-scale numerical model of groundwater flow in the saturated zone at Yucca Mountain was constructed and linked to particle tracking simulations to produce an estimate of the distribution of groundwater travel times from the potential repository to the boundary of the accessible environment. This effort and associated modeling of groundwater travel times in the unsaturated zone were undertaken to aid in the evaluation of compliance of the site with 10CFR960. These regulations stipulate that pre-waste-emplacement groundwater travel time to the accessible environment shall exceed 1,000 years along any path of likely and significant radionuclide travel

  10. A Groundwater Model to Assess Water Resource Impacts at the Brenda Solar Energy Zone

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John [Argonne National Lab. (ANL), Argonne, IL (United States); Carr, Adrianne E. [Argonne National Lab. (ANL), Argonne, IL (United States); Greer, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Bowen, Esther E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-12-01

    The purpose of this study is to develop a groundwater flow model to examine the influence of potential groundwater withdrawal to support utility-scale solar energy development at the Brenda Solar Energy Zone (SEZ), as a part of the Bureau of Land Management’s (BLM’s) Solar Energy Program.

  11. A Groundwater Model to Assess Water Resource Impacts at the Imperial East Solar Energy Zone

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John [Argonne National Lab. (ANL), Argonne, IL (United States); Greer, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); O' Connor, Ben L. [Argonne National Lab. (ANL), Argonne, IL (United States); Tompson, Andrew F.B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-12-01

    The purpose of this study is to develop a groundwater flow model to examine the influence of potential groundwater withdrawal to support the utility-scale solar energy development at the Imperial East Solar Energy Zone (SEZ) as a part of the Bureau of Land Management’s (BLM) solar energy program.

  12. Particle tracking for unsaturated-zone groundwater travel time analysis at Yucca Mountain

    International Nuclear Information System (INIS)

    Arnold, B.W.; Skinner, L.H.; Zieman, N.B.

    1995-01-01

    A particle tracking code developed to link numerical modeling of groundwater flow in the unsaturated zone to the analysis of groundwater travel times was used to produce preliminary estimates of the distribution of groundwater-travel time from a potential repository at Yucca Mountain, Nevada to the water table. Compliance with 10CFR960 requires the demonstration that pre-waste-emplacement groundwater travel time from the disturbed zone to the accessible environment is expected to exceed 1,000 years along any path of likely and significant radionuclide travel. The use of multiple particles and multiple realizations of the geology and parameter distributions in the unsaturated zone allows a probabilistic analysis of groundwater travel times that may be applied for evaluating compliance

  13. Vadose Zone Nitrate Transport Dynamics Resulting from Agricultural Groundwater Banking

    Science.gov (United States)

    Murphy, N. P.; McLaughlin, S.; Dahlke, H. E.

    2017-12-01

    In recent years, California's increased reliance on groundwater resources to meet agricultural and municipal demands has resulted in significant overdraft and water quality issues. Agricultural groundwater banking (AGB) has emerged as a promising groundwater replenishment opportunity in California; AGB is a form of managed aquifer recharge where farmland is flooded during the winter using excess surface water in order to recharge the underlying groundwater. Suitable farmland that is connected to water delivery systems is available for AGB throughout the Central Valley. However, questions remain how AGB could be implemented on fertilized agricultural fields such that nitrate leaching from the root zone is minimized. Here, we present results from field and soil column studies that investigate the transport dynamics of nitrogen in the root and deeper vadose zone during flooding events. We are specifically interested in estimating how timing and duration of flooding events affect percolation rates, leaching and nitrification/denitrification processes in three soil types within the Central Valley. Laboratory and field measurements include nitrogen (NO3-, NH4+, NO2-, N2O), redox potentials, total organic carbon, dissolved oxygen, moisture content and EC. Soil cores are collected in the field before and after recharge events up to a depth of 4m, while other sensors monitor field conditions continuously. Preliminary results from the three field sites show that significant portions of the applied floodwater (12-62 cm) infiltrated below the root zone: 96.1% (Delhi), 88.6% (Modesto) and 76.8% (Orland). Analysis of the soil cores indicate that 70% of the residual nitrate was flushed from the sandy soil, while the fine sandy loam showed only a 5% loss and in some cores even an increase in soil nitrate (in the upper 20cm). Column experiments support these trends and indicate that increases in soil nitrate in the upper root zone might be due to organic nitrogen mineralization and

  14. Aquifer Characterization and Groundwater Potential Assessment

    African Journals Online (AJOL)

    Timothy Ademakinwa

    Keywords: Aquifer Characterization, Groundwater Potential, Electrical Resistivity, Lithologic Logs ... State Water Corporation currently cannot meet the daily water ... METHOD OF STUDY ... sections which were constrained with the available.

  15. Submarine Groundwater Discharge in the Coastal Zone

    Science.gov (United States)

    Bakti, Hendra

    2018-02-01

    Indonesia is one of the archipelagic countries that has the longest coastline in the world. Because it is located in the tropics, in general it has a very high rainfall. Each island has a different morphology which is composed of a variety of rocks with different hydrogeological properties. This natural condition allows for the presence of groundwater in different amount in each island. The difference in groundwater hydraulics gradients in aquifer continuous to the sea has triggered the discharge of groundwater to offshore known as submarine groundwater discharge (SGD). Its presence can be as seepage or submarine springs with components derived from land and sea and a mixture between them. The understanding of SGD phenomenon is very important because it can be useful as a source of clean water in coastal areas, affecting marine health, and improving marine environment.

  16. Artificial groundwater recharge zones mapping using remote sensing and GIS: a case study in Indian Punjab.

    Science.gov (United States)

    Singh, Amanpreet; Panda, S N; Kumar, K S; Sharma, Chandra Shekhar

    2013-07-01

    Artificial groundwater recharge plays a vital role in sustainable management of groundwater resources. The present study was carried out to identify the artificial groundwater recharge zones in Bist Doab basin of Indian Punjab using remote sensing and geographical information system (GIS) for augmenting groundwater resources. The study area has been facing severe water scarcity due to intensive agriculture for the past few years. The thematic layers considered in the present study are: geomorphology (2004), geology (2004), land use/land cover (2008), drainage density, slope, soil texture (2000), aquifer transmissivity, and specific yield. Different themes and related features were assigned proper weights based on their relative contribution to groundwater recharge. Normalized weights were computed using the Saaty's analytic hierarchy process. Thematic layers were integrated in ArcGIS for delineation of artificial groundwater recharge zones. The recharge map thus obtained was divided into four zones (poor, moderate, good, and very good) based on their influence to groundwater recharge. Results indicate that 15, 18, 37, and 30 % of the study area falls under "poor," "moderate," "good," and "very good" groundwater recharge zones, respectively. The highest recharge potential area is located towards western and parts of middle region because of high infiltration rates caused due to the distribution of flood plains, alluvial plain, and agricultural land. The least effective recharge potential is in the eastern and middle parts of the study area due to low infiltration rate. The results of the study can be used to formulate an efficient groundwater management plan for sustainable utilization of limited groundwater resources.

  17. Coastal Zone Hazards Related to Groundwater-Surface Water Interactions and Groundwater Flooding

    Science.gov (United States)

    Kontar, Y. A.; Ozorovich, Y. R.; Salokhiddinov, A. T.

    2009-12-01

    Worldwide, as many as half a million people have died in natural and man-made disasters since the turn of the 21st century (Wirtz, 2008). Further, natural and man-made hazards can lead to extreme financial losses (Elsner et al, 2009). Hazards, hydrological and geophysical risk analysis related to groundwater-surface water interactions and groundwater flooding have been to a large extent under-emphasized for coastal zone applications either due to economical limitations or underestimation of its significance. This is particularly true for tsunamis creating salt water intrusion to coastal aquifers, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models (Geist and Parsons, 2006), and to increasing mineralization of potable water because of intensive water diversions and also the abundance of highly toxic pollutants (mainly pesticides) in water, air and food, which contribute to the deterioration of the coastal population's health (Glantz, 2007). In the wake of pressing environmental and economic issues, it is of prime importance for the scientific community to shed light onto the great efforts by hydrologists and geophysicists to quantify conceptual uncertainties and to provide quality assurances of potential coastal zone hazard evaluation and prediction. This paper proposes consideration of two case studies which are important and significant for future development and essential for feasibility studies of hazards in the coastal zone. The territory of the Aral Sea Region in Central Asia is known as an ecological disaster coastal zone (Zavialov, 2005). It is now obvious that, in order to provide reasonable living conditions to the coastal zone population, it is first of all necessary to drastically improve the quality of the water dedicated to human needs. Due to their intensive pollution by industrial wastes and by drainage waters from irrigated fields, the Syr Darya and Amu Darya rivers can no longer be considered

  18. Aquifer Characterization and Groundwater Potential Evaluation in Sedimentary Rock Formation

    Science.gov (United States)

    Ashraf, M. A. M.; Yusoh, R.; Sazalil, M. A.; Abidin, M. H. Z.

    2018-04-01

    This study was conducted to characterize the aquifer and evaluate the ground water potential in the formation of sedimentary rocks. Electrical resistivity and drilling methods were used to develop subsurface soil profile for determining suitable location for tube well construction. The electrical resistivity method was used to infer the subsurface soil layer by use of three types of arrays, namely, the pole–dipole, Wenner, and Schlumberger arrays. The surveys were conducted using ABEM Terrameter LS System, and the results were analyzed using 2D resistivity inversion program (RES2DINV) software. The survey alignments were performed with maximum electrode spreads of 400 and 800 m by employing two different resistivity survey lines at the targeted zone. The images were presented in the form of 2D resistivity profiles to provide a clear view of the distribution of interbedded sandstone, siltstone, and shale as well as the potential groundwater zones. The potential groundwater zones identified from the resistivity results were confirmed using pumping, step drawdown, and recovery tests. The combination among the three arrays and the correlation between the well log and pumping test are reliable and successful in identifying potential favorable zones for obtaining groundwater in the study area.

  19. Application of remote sensing and GIS for the demarcation of groundwater potential zones of a river basin in Kerala, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Gopinath, G.; Seralathan, P.

    on the movement and behaviour of the groundwater of this basin. The integration of conventional and remote sensing data has been made through geographic information system (GIS) and it is found that about 50% of the area can be identified as very good or good...

  20. Identification of groundwater prospective zones by using remote ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 114; Issue 5. Identification of groundwater prospective zones by using remote sensing and geoelectrical methods in Jharia and Raniganj coalfields, Dhanbad district, Jharkhand state. Basudeo Rai A Tiwari V S Dubey. Volume 114 Issue 5 October 2005 pp 515-522 ...

  1. Onsite disposal of radioactive waste: Estimating potential groundwater contamination

    International Nuclear Information System (INIS)

    Goode, D.J.; Neuder, S.M.; Pennifill, R.A.; Ginn, T.

    1986-11-01

    Volumes 1 and 2 of this report describe the NRC's methodology for assessing the potential public health and environmental impacts associated with onsite disposal of very low activity radioactive materials. This volume (Vol. 3) describes a general methodology for predicting potential groundwater contamination from onsite disposal. The methodology includes formulating a conceptual model, representing the conceptual model mathematically, estimating conservative parameters, and predicting receptor concentrations. Processes which must generally be considered in the methodology include infiltration, leaching of radionuclides from the waste, transport to the saturated zone, transport within the saturated zone, and withdrawal at a receptor location. A case study of shallow burial of iodine-125 illustrates application of the MOCMOD84 version of the US Geological Survey's 2-D solute transport model and a corresponding analytical solution. The appendices include a description and listing of MOCMOD84, descriptions of several analytical solution techniques, and a procedure for estimating conservative groundwater velocity values

  2. Assessment of groundwater potential in Ankobra River Basin

    International Nuclear Information System (INIS)

    Nyarkoh, Charles Prince

    2011-08-01

    Ankobra river basin is endowed with many rich natural resources. The mining activities in the basin and the proposed hydropower generation on the Ankobra river as well as oil discovery in the Western Region would lead to the establishing of new industries in the basin. These would certainly lead to potential population growth. As a result of these developments, there would be stress on surface water resources and therefore there would be demand for ground water. A research was carried out to assess groundwater supply. Hydrogeological data was used to evaluate the ground water storage in the basement complex, regolith. The relevant aquifer characteristics/parameters (extent of the study area, thickness of the ground water zone in the regolith, the porosity and specific capacity of the aquifer zones) were used to compute total groundwater storage and recoverable storage. The groundwater contribution to stream flow was computed using mean monthly discharge data from the filled data and hydrograph drawn. The base flow was then determined from the hydrograph separation using the straight line method. The groundwater potential in the Ankobra basin is 45.82*10 9 m 3 while the recoverable groundwater storage is 29.39*10 9 m 3 . The base flow computed was 13.75m 3/ s. Investigations into groundwater chemistry with particular references to physico-chemical parameters (quality) was analysed. The constituents fall within the acceptable limits of the Ghana Standard Board (GSB) for drinking water standard and are satisfactory for human consumption. However, Tamso, Wantenem, Gyaman, Beyim communities exceeded the GSB'S recommended values of PH (6.5-8.5) and chloride ( 250 mg/I) respectively for drinking water standard.(author)

  3. Groundwater/Vadose Zone Integration Project Management Plan

    International Nuclear Information System (INIS)

    Hughes, M. C.

    1999-01-01

    This Project Management Plan (PMP) defines the authorities, roles, and responsibilities of the US Department of Energy (DOE), Richland Operations Office (RL) and those contractor organizations participating in the Hanford Site' s Groundwater/Vadose Zone (GW/VZ) Integration Project. The PMP also describes the planning and control systems, business processes, and other management tools needed to properly and consistently conduct the Integration Project scope of work

  4. Underground mining of the lower 163 zone through groundwater drainage at the Eagle Point Mine

    International Nuclear Information System (INIS)

    Robson, D.M.; Bashir, R.; Thomson, J.; Klemmer, S.; Rigden, A.

    2010-01-01

    The Eagle Point Mine is part of the Cameco Rabbit Lake Operation. The mine produces uranium ore using the long-hole, vertical and horizontal retreat mining method. The majority of the mine workings are under Wollaston Lake and cementitious grouting is used as one of the water control measures. Historical groundwater table in the mining area was close to ground surface. The Lower 163 Zone encompasses an estimated 4.2 million pounds U_3O_8 geological resource that was not considered feasible to mine due to the expected groundwater flows in the area. Cross-hole testing was conducted to better understand the groundwater flow through various geologic units. A local depressurization test was conducted to assess the potential for lowering the water table. Following testing an active depressurization was conducted to lower the groundwater table below the planned mining areas. This resulted in safe and drier mining conditions and allowed for the successful extraction of the ore body. (author)

  5. Analysis on groundwater evolution and interlayer oxidation zone position at the southern margin of Yilin basin

    International Nuclear Information System (INIS)

    Zhang Guanghui

    2007-01-01

    This paper discusses the development and evolution history of groundwater and its reworking to the interlayer oxidation zone, hydrogeochemical zonation of interlayer oxidation zone, mechanism of water-rock interaction and transportation pattern of uranium in the water in Yili Basin. It is suggested that groundwater is one of the important factors to control the development of interlayer oxidation zone and uranium mineralization. (authors)

  6. A GIS/Remote Sensing-based methodology for groundwater potentiality assessment in Tirnavos area, Greece

    Science.gov (United States)

    Oikonomidis, D.; Dimogianni, S.; Kazakis, N.; Voudouris, K.

    2015-06-01

    The aim of this paper is to assess the groundwater potentiality combining Geographic Information Systems and Remote Sensing with data obtained from the field, as an additional tool to the hydrogeological research. The present study was elaborated in the broader area of Tirnavos, covering 419.4 km2. The study area is located in Thessaly (central Greece) and is crossed by two rivers, Pinios and Titarisios. Agriculture is one of the main elements of Thessaly's economy resulting in intense agricultural activity and consequently increased exploitation of groundwater resources. Geographic Information Systems (GIS) and Remote Sensing (RS) were used in order to create a map that depicts the likelihood of existence of groundwater, consisting of five classes, showing the groundwater potentiality and ranging from very high to very low. The extraction of this map is based on the study of input data such as: rainfall, potential recharge, lithology, lineament density, slope, drainage density and depth to groundwater. Weights were assigned to all these factors according to their relevance to groundwater potential and eventually a map based on weighted spatial modeling system was created. Furthermore, a groundwater quality suitability map was illustrated by overlaying the groundwater potentiality map with the map showing the potential zones for drinking groundwater in the study area. The results provide significant information and the maps could be used from local authorities for groundwater exploitation and management.

  7. GIS-based bivariate statistical techniques for groundwater potential analysis (an example of Iran)

    Science.gov (United States)

    Haghizadeh, Ali; Moghaddam, Davoud Davoudi; Pourghasemi, Hamid Reza

    2017-12-01

    Groundwater potential analysis prepares better comprehension of hydrological settings of different regions. This study shows the potency of two GIS-based data driven bivariate techniques namely statistical index (SI) and Dempster-Shafer theory (DST) to analyze groundwater potential in Broujerd region of Iran. The research was done using 11 groundwater conditioning factors and 496 spring positions. Based on the ground water potential maps (GPMs) of SI and DST methods, 24.22% and 23.74% of the study area is covered by poor zone of groundwater potential, and 43.93% and 36.3% of Broujerd region is covered by good and very good potential zones, respectively. The validation of outcomes displayed that area under the curve (AUC) of SI and DST techniques are 81.23% and 79.41%, respectively, which shows SI method has slightly a better performance than the DST technique. Therefore, SI and DST methods are advantageous to analyze groundwater capacity and scrutinize the complicated relation between groundwater occurrence and groundwater conditioning factors, which permits investigation of both systemic and stochastic uncertainty. Finally, it can be realized that these techniques are very beneficial for groundwater potential analyzing and can be practical for water-resource management experts.

  8. Characteristic groundwater level regimes in the capture zones of radial collector wells and importance of identification (Case study of Belgrade Groundwater Source

    Directory of Open Access Journals (Sweden)

    Božović Đorđije

    2016-01-01

    Full Text Available Assessment of the operating modes of radial collector wells reveals that the pumping levels in the well caissons are very low relative to the depth/elevation of the laterals, which is a common occurrence at Belgrade Groundwater Source. As a result, well discharge capacities vary over a broad range and groundwater levels in the capture zones differ even when the rate of discharge is the same. Five characteristic groundwater level regimes are identified and their origin is analyzed using representative wells as examples. The scope and type of background information needed to identify the groundwater level regime are presented and an interpretation approach is proposed for preliminary assessment of the aquifer potential at the well site for providing the needed amount of groundwater. [Projekat Ministarstva nauke Republike Srbije, br. OI176022, br. TR33039 i br. III43004

  9. Imbalance in Groundwater-Surface Water Interactions and its Relationship to the Coastal Zone Hazards

    Science.gov (United States)

    Kontar, Y. A.; Ozorovich, Y. R.; Salokhiddinov, A. T.

    2011-12-01

    We report here some efforts and results in studying the imbalance in groundwater-surface water interactions and processes of groundwater-surface water interactions and groundwater flooding creating hazards in the coastal zones. Hazards, hydrological and geophysical risk analysis related to imbalance in groundwater-surface water interactions and groundwater flooding have been to a large extent under-emphasized for coastal zone applications either due to economical limitations or underestimation of significance of imbalance in groundwater-surface water interactions. This is particularly true for tsunamis creating salt water intrusion to coastal aquifers, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models, and to increasing mineralization of potable water because of intensive water diversions and also the abundance of highly toxic pollutants (mainly pesticides) in water, air and food, which contribute to the deterioration of the coastal population's health. In the wake of pressing environmental and economic issues, it is of prime importance for the scientific community to shed light onto the great efforts by hydrologists and geophysicists to quantify conceptual uncertainties and to provide quality assurances of potential coastal zone hazard evaluation and prediction under conditions of imbalance in groundwater-surface water interactions. This paper proposes consideration of two case studies which are important and significant for future understanding of a concept of imbalance in groundwater-surface water interactions and development and essential for feasibility studies of hazards in the coastal zone. The territory of the Aral Sea Region in Central Asia is known as an ecological disaster coastal zone. It is now obvious that, in order to provide reasonable living conditions to the coastal zone population, it is first of all necessary to drastically improve the quality of the water dedicated to human needs. Due

  10. Application of remote sensing, GIS and MCA techniques for delineating groundwater prospect zones in Kashipur block, Purulia district, West Bengal

    Science.gov (United States)

    Nag, S. K.; Kundu, Anindita

    2018-03-01

    Demand of groundwater resources has increased manifold with population expansion as well as with the advent of modern civilization. Assessment, planning and management of groundwater resource are becoming crucial and extremely urgent in recent time. The study area belongs to Kashipur block, Purulia district, West Bengal. The area is characterized with dry climate and hard rock terrain. The objective of this study is to delineate groundwater potential zone for the assessment of groundwater availability using remote sensing, GIS and MCA techniques. Different thematic layers such as hydrogeomorphology, slope and lineament density maps have been transformed to raster data in TNT mips pro2012. To assign weights and ranks to different input factor maps, multi-influencing factor (MIF) technique has been used. The weights assigned to each factor have been computed statistically. Weighted index overlay modeling technique was used to develop a groundwater potential zone map with three weighted and scored parameters. Finally, the study area has been categorized into four distinct groundwater potential zones—excellent 1.5% (6.45 sq. km), good 53% (227.9 sq. km), moderate 45% (193.5 sq. km.) and poor 0.5% (2.15 sq. km). The outcome of the present study will help local authorities, researchers, decision makers and planners in formulating proper planning and management of groundwater resources in different hydrogeological situations.

  11. Potential groundwater contribution to Amazon evapotranspiration

    Science.gov (United States)

    Fan, Y.; Miguez-Macho, G.

    2010-07-01

    Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations show enhanced growth in response to higher radiation under less cloudy skies, indicating an adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution). Here we assess the importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of water table depth from observations and groundwater modeling, and a map of potential capillary flux these water table depths can sustain. The maps show that the water table beneath the Amazon can be quite shallow in lowlands and river valleys (2.1 mm day-1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day-1 across nine study sites. Current models simulate a large-scale reduction in dry-season photosynthesis under today's climate and a possible dieback under projected future climate with a longer dry season, converting the Amazon from a net carbon sink to a source and accelerating warming. The inclusion of groundwater and capillary flux may modify the model results.

  12. Potential impacts of climate change and variability on groundwater ...

    African Journals Online (AJOL)

    Potential impacts of climate change and variability on groundwater resources in Nigeria. ... African Journal of Environmental Science and Technology ... of climate change induced groundwater impacts due to largely multi-scale local and regional heterogeneity, there is need to evaluate groundwater resources, quality and ...

  13. Heterogeneous hyporheic zone dechlorination of a TCE groundwater plume discharging to an urban river reach.

    Science.gov (United States)

    Freitas, Juliana G; Rivett, Michael O; Roche, Rachel S; Durrant Neé Cleverly, Megan; Walker, Caroline; Tellam, John H

    2015-02-01

    The typically elevated natural attenuation capacity of riverbed-hyporheic zones is expected to decrease chlorinated hydrocarbon (CHC) groundwater plume discharges to river receptors through dechlorination reactions. The aim of this study was to assess physico-chemical processes controlling field-scale variation in riverbed-hyporheic zone dechlorination of a TCE groundwater plume discharge to an urban river reach. The 50-m long pool-riffle-glide reach of the River Tame in Birmingham (UK) studied is a heterogeneous high energy river environment. The shallow riverbed was instrumented with a detailed network of multilevel samplers. Freeze coring revealed a geologically heterogeneous and poorly sorted riverbed. A chlorine number reduction approach provided a quantitative indicator of CHC dechlorination. Three sub-reaches of contrasting behaviour were identified. Greatest dechlorination occurred in the riffle sub-reach that was characterised by hyporheic zone flows, moderate sulphate concentrations and pH, anaerobic conditions, low iron, but elevated manganese concentrations with evidence of sulphate reduction. Transient hyporheic zone flows allowing input to varying riverbed depths of organic matter are anticipated to be a key control. The glide sub-reach displayed negligible dechlorination attributed to the predominant groundwater baseflow discharge condition, absence of hyporheic zone, transition to more oxic conditions and elevated sulphate concentrations expected to locally inhibit dechlorination. The tail-of-pool-riffle sub-reach exhibited patchy dechlorination that was attributed to sub-reach complexities including significant flow bypass of a low permeability, high organic matter, silty unit of high dechlorination potential. A process-based conceptual model of reach-scale dechlorination variability was developed. Key findings of practitioner relevance were: riverbed-hyporheic zone CHC dechlorination may provide only a partial, somewhat patchy barrier to CHC

  14. Potential groundwater contribution to Amazon evapotranspiration

    Directory of Open Access Journals (Sweden)

    Y. Fan

    2010-10-01

    Full Text Available Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations do not support these results, indicating adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution, both absent in the models. Here we provide a first-order assessment of the potential importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of equilibrium water table depth from available observations and a groundwater model simulation constrained by these observations. We then present a map of maximum capillary flux these water table depths, combined with the fine-textured soils in the Amazon, can potentially support. The maps show that the water table beneath the Amazon can be shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia. These water table depths can potentially accommodate a maximum capillary flux of 2.1 mm day−1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day−1 across nine study sites.

    We note that the results presented here are based on limited observations and simple equilibrium model calculations, and as such, have important limitations and must be interpreted accordingly. The potential capillary fluxes are not indicative of their contribution to the actual evapotranspiration, and they are only an assessment of the possible rate at which this flux can occur, to illustrate the power of soil capillary force acting on a shallow water table in fine textured soils. They may over-estimate the actual flux where the surface soils remain moist. Their contribution to the actual evapotranspiration can only be assessed through fully coupled model simulation of the dynamic feedbacks between soil water and groundwater with sub-daily climate forcing. The equilibrium water table

  15. Prediction of groundwater flowing well zone at An-Najif Province, central Iraq using evidential belief functions model and GIS.

    Science.gov (United States)

    Al-Abadi, Alaa M; Pradhan, Biswajeet; Shahid, Shamsuddin

    2015-10-01

    The objective of this study is to delineate groundwater flowing well zone potential in An-Najif Province of Iraq in a data-driven evidential belief function model developed in a geographical information system (GIS) environment. An inventory map of 68 groundwater flowing wells was prepared through field survey. Seventy percent or 43 wells were used for training the evidential belief functions model and the reset 30 % or 19 wells were used for validation of the model. Seven groundwater conditioning factors mostly derived from RS were used, namely elevation, slope angle, curvature, topographic wetness index, stream power index, lithological units, and distance to the Euphrates River in this study. The relationship between training flowing well locations and the conditioning factors were investigated using evidential belief functions technique in a GIS environment. The integrated belief values were classified into five categories using natural break classification scheme to predict spatial zoning of groundwater flowing well, namely very low (0.17-0.34), low (0.34-0.46), moderate (0.46-0.58), high (0.58-0.80), and very high (0.80-0.99). The results show that very low and low zones cover 72 % (19,282 km(2)) of the study area mostly clustered in the central part, the moderate zone concentrated in the west part covers 13 % (3481 km(2)), and the high and very high zones extended over the northern part cover 15 % (3977 km(2)) of the study area. The vast spatial extension of very low and low zones indicates that groundwater flowing wells potential in the study area is low. The performance of the evidential belief functions spatial model was validated using the receiver operating characteristic curve. A success rate of 0.95 and a prediction rate of 0.94 were estimated from the area under relative operating characteristics curves, which indicate that the developed model has excellent capability to predict groundwater flowing well zones. The produced map of groundwater

  16. Arid-zone groundwater recharge and palaeorecharge: insights from the radioisotope chlorine-36

    International Nuclear Information System (INIS)

    Jacobson, G.; Wischusen, J.; Cresswell, R.; Fifield, K.

    1998-01-01

    AGSO's collaborative 'Western water' study of groundwater resources in Aboriginal lands in the southwest Northern Territory arid zone, has applied the radioisotope 36 CI and 14 C to investigate the sustainability of community water supplies drawn from shallow aquifers in the Papunya-Kintore-Yuendumu area. The 36 CI results have important implications for groundwater management throughout the arid zone, because substantial recharge occurs only during favourable, wet, interglacial climatic regimes. this has important implications for groundwater management in this area and elsewhere in central Australia, where most of the community water supplies depend on 'old' stored groundwater

  17. Application of GIS based data driven evidential belief function model to predict groundwater potential zonation

    Science.gov (United States)

    Nampak, Haleh; Pradhan, Biswajeet; Manap, Mohammad Abd

    2014-05-01

    The objective of this paper is to exploit potential application of an evidential belief function (EBF) model for spatial prediction of groundwater productivity at Langat basin area, Malaysia using geographic information system (GIS) technique. About 125 groundwater yield data were collected from well locations. Subsequently, the groundwater yield was divided into high (⩾11 m3/h) and low yields (divided into a testing dataset 70% (42 wells) for training the model and the remaining 30% (18 wells) was used for validation purpose. To perform cross validation, the frequency ratio (FR) approach was applied into remaining groundwater wells with low yield to show the spatial correlation between the low potential zones of groundwater productivity. A total of twelve groundwater conditioning factors that affect the storage of groundwater occurrences were derived from various data sources such as satellite based imagery, topographic maps and associated database. Those twelve groundwater conditioning factors are elevation, slope, curvature, stream power index (SPI), topographic wetness index (TWI), drainage density, lithology, lineament density, land use, normalized difference vegetation index (NDVI), soil and rainfall. Subsequently, the Dempster-Shafer theory of evidence model was applied to prepare the groundwater potential map. Finally, the result of groundwater potential map derived from belief map was validated using testing data. Furthermore, to compare the performance of the EBF result, logistic regression model was applied. The success-rate and prediction-rate curves were computed to estimate the efficiency of the employed EBF model compared to LR method. The validation results demonstrated that the success-rate for EBF and LR methods were 83% and 82% respectively. The area under the curve for prediction-rate of EBF and LR methods were calculated 78% and 72% respectively. The outputs achieved from the current research proved the efficiency of EBF in groundwater

  18. Small-scale spatial variability of phenoxy acid mineralization potentials in transition zones with a multidisciplinary approach

    DEFF Research Database (Denmark)

    Pazarbasi, Meric Batioglu

    The phenoxy acid group of herbicides is widely used to control broadleaf weeds, and it contaminates groundwater and surface water by leaching from agricultural soil or landfills. Due to the distinct vertical and horizontal gradients in nutrients and hydrologic exchange in transition zones...... in two transition zones, (1) the interfaces of unsaturated and saturated zones and (2) groundwater and surface water. Small-scale spatial variability of phenoxy acids was previously shown in topsoil; however, such small-scale studies are scarce in subsurface environments. We therefore studied the factors...... classes in the different mineralization potentials of discharge zones. Understanding of the natural attenuation potential of groundwater-surface water transition zones is important for stream water protection. In landfill-impacted groundwater-surface water interface, we further analyzed bacterial...

  19. Geoelectric investigation to delineate groundwater potential and ...

    Indian Academy of Sciences (India)

    2School of Environment and Earth Sciences, North Maharashtra University, Jalgaon 425 001, India. 3Groundwater ...... medium acts as a natural filter to percolating fluid and that its ... Atakpo E A 2013 Aquifer vulnerability investigation using.

  20. Groundwater potential for water supply during droughts in Korea

    Science.gov (United States)

    Hyun, Y.; Cha, E.; Moon, H. J.

    2016-12-01

    Droughts have been receiving much attention in Korea because severe droughts occurred in recent years, causing significant social, economic and environmental damages in some regions. Residents in agricultural area, most of all, were most damaged by droughts with lack of available water supplies to meet crop water demands. In order to mitigate drought damages, we present a strategy to keep from agricultural droughts by using groundwater to meet water supply as a potential water resource in agricultural areas. In this study, we analyze drought severity and the groundwater potential to mitigate social and environmental damages caused by droughts in Korea. We evaluate drought severity by analyzing spatial and temporal meteorological and hydrological data such as rainfall, water supply and demand. For drought severity, we use effective drought index along with the standardized precipitation index (SPI) and standardized runoff index(SRI). Water deficit during the drought period is also quantified to consider social and environmental impact of droughts. Then we assess the feasibility of using groundwater as a potential source for groundwater impact mitigation. Results show that the agricultural areas are more vulnerable to droughts and use of groundwater as an emergency water resource is feasible in some regions. For a case study, we select Jeong-Sun area located in Kangwon providence having well-developed Karst aquifers and surrounded by mountains. For Jeong-Sun area, we quantify groundwater potential use, design the method of water supply by using groundwater, and assess its economic benefit. Results show that water supply system with groundwater abstraction can be a good strategy when droughts are severe for an emergency water supply in Jeong-Sun area, and groundwater can also be used not only for a dry season water supply resource, but for everyday water supply system. This case study results can further be applicable to some regions with no sufficient water

  1. Nitrogen fate in a subtropical mangrove swamp: Potential association with seawater-groundwater exchange.

    Science.gov (United States)

    Xiao, Kai; Wu, Jiapeng; Li, Hailong; Hong, Yiguo; Wilson, Alicia M; Jiao, Jiu Jimmy; Shananan, Meghan

    2018-04-18

    Coastal mangrove swamps play an important role in nutrient cycling at the land-ocean boundary. However, little is known about the role of periodic seawater-groundwater exchange in the nitrogen cycling processes. Seawater-groundwater exchange rates and inorganic nitrogen concentrations were investigated along a shore-perpendicular intertidal transect in Daya Bay, China. The intertidal transect comprises three hydrologic subzones (tidal creek, mangrove and bare mudflat zones), each with different physicochemical characteristics. Salinity and hydraulic head measurements taken along the transect were used to estimate the exchange rates between seawater and groundwater over a spring-neap tidal cycle. Results showed that the maximum seawater-groundwater exchange occurred within the tidal creek zone, which facilitated high-oxygen seawater infiltration and subsequent nitrification. In contrast, the lowest exchange rate found in the mangrove zone caused over-loading of organic matter and longer groundwater residence times. This created an anoxic environment conducive to nitrogen loss through the anammox and denitrification processes. Potential oxidation rates of ammonia and nitrite were measured by the rapid and high-throughput method and rates of denitrification and anammox were measured by the modified membrane inlet mass spectrometry (MIMS) with isotope pairing, respectively. In the whole transect, denitrification accounted for 90% of the total nitrogen loss, and anammox accounted for the remaining 10%. The average nitrogen removal rate was about 2.07g per day per cubic meter of mangrove sediments. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Quantification of groundwater recharge through application of pilot techniques in the unsaturated zone.

    Science.gov (United States)

    Kallioras, Andreas; Piepenbrink, Matthias; Schuth, Christoph; Pfletschinger, Heike; Dietrich, Peter; Koeniger, Franz; Rausch, Randolf

    2010-05-01

    Accurate determination of groundwater recharge is a key issue for the "smart mining" of groundwater resources. Groundwater recharge estimation techniques depend on the investigated hydrologic zone, and therefore main approaches are based on (a) unsaturated zone, (b) saturated zone and (c) surface water studies. This research contributes to the determination of groundwater recharge by investigating the infiltration of groundwater through the unsaturated zone. The investigations are conducted through the application of a combination of different pilot field as well as lab techniques. The field techniques include the installation of specially designed Time Domain Reflectometry (TDR) sensors, at different depths within the unsaturated zone for in-situ and continuous measurements of the volumetric pore water content. Additionally, the extraction of pore water -for analysis of its isotopic composition- from multilevel undisturbed soil samples through significant depths within the unsaturated zone column, enables the dating of the groundwater age through the determination of its isotopic composition. The in-situ investigation of the unsaturated zone is complemented by the determination of high resolution temperature profiles. The installation of the pilot TDR sensors is achieved by using direct push methods at significant depths within the unsaturated zone, providing continuous readings of the soil moisture content. The direct push methods are also ideal for multilevel sampling of undisturbed -without using any drilling fluids which affect the isotopic composition of the containing pore water- soil and consequent extraction of the included pore water for further isotopic determination. The pore water is extracted by applying the method of azeotropic distillation; a method which has the least isotopic fractionation effects on groundwater samples. The determination of different isotopic signals such as 18O, 2H, 3H, and 36Cl, aims to the investigation of groundwater transit

  3. Establishment of Groundwater Arsenic Potential Distribution and Discrimination in Taiwan

    Science.gov (United States)

    Tsai, Kuo Sheng; Chen, Yu Ying; Chung Liu, Chih; Lin, Chien Wen

    2016-04-01

    According to the last 10 years groundwater monitoring data in Taiwan, Arsenic concentration increase rapidly in some areas, similar to Bengal and India, the main source of Arsenic-polluted groundwater is geological sediments, through reducing reactions. There are many researches indicate that high concentration of Arsenic in groundwater poses the risk to water safety, for example, the farm lands irrigation water contains Arsenic cause the concentration of Arsenic increase in soil and crops. Based on the management of water usage instead of remediation in the situation of insufficient water. Taiwan EPA has been developed the procedures of Arsenic contamination potential area establishment and source discriminated process. Taiwan EPA use the procedures to determine the management of using groundwater, and the proposing usage of Arsenic groundwater accordance with different objects. Agencies could cooperate with the water quality standard or water needs, studying appropriate water purification methods and the groundwater depth, water consumption, thus achieve the goal of water safety and environmental protection, as a reference of policy to control total Arsenic concentration in groundwater. Keywords: Arsenic; Distribution; Discrimination; Pollution potential area of Arsenic; Origin evaluation of groundwater Arsenic

  4. Quantifying Potential Groundwater Recharge In South Texas

    Science.gov (United States)

    Basant, S.; Zhou, Y.; Leite, P. A.; Wilcox, B. P.

    2015-12-01

    Groundwater in South Texas is heavily relied on for human consumption and irrigation for food crops. Like most of the south west US, woody encroachment has altered the grassland ecosystems here too. While brush removal has been widely implemented in Texas with the objective of increasing groundwater recharge, the linkage between vegetation and groundwater recharge in South Texas is still unclear. Studies have been conducted to understand plant-root-water dynamics at the scale of plants. However, little work has been done to quantify the changes in soil water and deep percolation at the landscape scale. Modeling water flow through soil profiles can provide an estimate of the total water flowing into deep percolation. These models are especially powerful with parameterized and calibrated with long term soil water data. In this study we parameterize the HYDRUS soil water model using long term soil water data collected in Jim Wells County in South Texas. Soil water was measured at every 20 cm intervals up to a depth of 200 cm. The parameterized model will be used to simulate soil water dynamics under a variety of precipitation regimes ranging from well above normal to severe drought conditions. The results from the model will be compared with the changes in soil moisture profile observed in response to vegetation cover and treatments from a study in a similar. Comparative studies like this can be used to build new and strengthen existing hypotheses regarding deep percolation and the role of soil texture and vegetation in groundwater recharge.

  5. Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

    Science.gov (United States)

    Abdalla, Fathy; Khalil, Ramadan

    2018-05-01

    The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

  6. Application of Dempster-Shafer theory of evidence model to geoelectric and hydraulic parameters for groundwater potential zonation

    Science.gov (United States)

    Mogaji, Kehinde Anthony; Lim, Hwee San

    2018-06-01

    The application of a GIS - based Dempster - Shafer data driven model named as evidential belief function EBF- methodology to groundwater potential conditioning factors (GPCFs) derived from geophysical and hydrogeological data sets for assessing groundwater potentiality was presented in this study. The proposed method's efficacy in managing degree of uncertainty in spatial predictive models motivated this research. The method procedural approaches entail firstly, the database containing groundwater data records (bore wells location inventory, hydrogeological data record, etc.) and geophysical measurement data construction. From the database, different influencing groundwater occurrence factors, namely aquifer layer thickness, aquifer layer resistivity, overburden material resistivity, overburden material thickness, aquifer hydraulic conductivity and aquifer transmissivity were extracted and prepared. Further, the bore well location inventories were partitioned randomly into a ratio of 70% (19 wells) for model training and 30% (9 wells) for model testing. The synthesized of the GPCFs via applying the DS - EBF model algorithms produced the groundwater productivity potential index (GPPI) map which demarcated the area into low - medium, medium, medium - high and high potential zones. The analyzed percentage degree of uncertainty for the predicted lows potential zones classes and mediums/highs potential zones classes are >10% and used by local authorities for groundwater exploitation and management in the area.

  7. Interpretation of environmental isotopic groundwater data. Arid and semi-arid zones

    International Nuclear Information System (INIS)

    Geyh, M.A.

    1980-01-01

    Various hydrodynamic aspects are discussed in order to show their implication for the hydrogeological interpretation of environmental isotope and hydrochemical groundwater data. Special attention is drawn to radiocarbon and tritium studies carried out in arid and semi-arid zones. An exponential model has been utilized to determine the mean residence time of the long-term water from springs in karst and crystalline regions. Hydrogeological parameters such as the porosity can be checked by this result. In addition, the exponential model offers the possibility of determining the initial 14 C content of spring water, which is sensitively dependent on the soil of the recharge area. A base-flow model has been introduced to interpret the 14 C and 3 H data of groundwater samples from older karst regions. Differences between pumped and drawn samples exist with respect to the groundwater budget. Owing to pumping, the old base flow is accelerated and becomes enriched in pumped groundwater in comparison to the short-term water. Radiocarbon ages of groundwater in alluvium may be dubious because of isotope exchange with the CO 2 in the root zone along the river bank. Under confined conditions 14 C groundwater ages are diminished if the hydraulic head of the confined aquifer is lower than that of the shallow one. This is due to the radiocarbon downwards transport by convection of shallow groundwater. The same effect occurs, though much faster, if the groundwater table is depleted by groundwater withdrawal. The decrease of the radiocarbon groundwater ages in time can be used to determine the hydraulic transmissibility coefficient of the aquitarde. According to the practical and theoretic results obtained the hydrodynamic aspects require at least the same attention for the interpretation of environmental isotope and hydrochemical data of groundwater as do hydrochemical and isotope fractionation processes. (author)

  8. Groundwater and solute transport modeling at Hyporheic zone of upper part Citarum River

    Science.gov (United States)

    Iskandar, Irwan; Farazi, Hendy; Fadhilah, Rahmat; Purnandi, Cipto; Notosiswoyo, Sudarto

    2017-06-01

    Groundwater and surface water interaction is an interesting topic to be studied related to the water resources and environmental studies. The study of interaction between groundwater and river water at the Upper Part Citarum River aims to know the contribution of groundwater to the river or reversely and also solute transport of dissolved ions between them. Analysis of drill logs, vertical electrical sounding at the selected sections, measurement of dissolved ions, and groundwater modeling were applied to determine the flow and solute transport phenomena at the hyporheic zone. It showed the hyporheic zone dominated by silt and clay with hydraulic conductivity range from 10-4∼10-8 m/s. The groundwater flowing into the river with very low gradient and it shows that the Citarum River is a gaining stream. The groundwater modeling shows direct seepage of groundwater into the Citarum River is only 186 l/s, very small compared to the total discharge of the river. Total dissolved ions of the groundwater ranged from 200 to 480 ppm while the river water range from 200 to 2,000 ppm. Based on solute transport modeling it indicates dissolved ions dispersion of the Citarum River into groundwater may occur in some areas such as Bojongsoang-Dayeuh Kolot and Nanjung. This situation would increase the dissolved ions in groundwater in the region due to the contribution of the Citarum River. The results of the research can be a reference for further studies related to the mechanism of transport of the pollutants in the groundwater around the Citarum River.

  9. Groundwater Flow and Radionuclide Transport in Fault Zones in Granitic Rock

    International Nuclear Information System (INIS)

    Geier, Joel Edward

    2004-12-01

    Fault zones are potential paths for release of radioactive nuclides from radioactive-waste repositories in granitic rock. This research considers detailed maps of en echelon fault zones at two sites in southern Sweden, as a basis for analyses of how their internal geometry can influence groundwater flow and transport of radioactive nuclides. Fracture intensity within these zones is anisotropic and correlated over scales of several meters along strike, corresponding to the length and spacing of the en echelon steps. Flow modeling indicates these properties lead to correlation of zone transmissivity over similar scales. Intensity of fractures in the damage zone adjoining en echelon segments decreases exponentially with distance. These fractures are linked to en echelon segments as a hierarchical pattern of branches. Echelon steps also show a hierarchical internal structure. These traits suggest a fractal increase in the amount of pore volume that solute can access by diffusive mass transfer, with increasing distance from en echelon segments. Consequences may include tailing of solute breakthrough curves, similar to that observed in underground tracer experiments at one of the mapping sites. The implications of echelon-zone architecture are evaluated by numerical simulation of flow and solute transport in 2-D network models, including deterministic models based directly on mapping data, and a statistical model. The simulations account for advection, diffusion-controlled mixing across streamlines within fractures and at intersections, and diffusion into both stagnant branch fractures and macroscopically unfractured matrix. The simulations show that secondary fractures contribute to retardation of solute, although their net effect is sensitive to assumptions regarding heterogeneity of transmissivity and transport aperture. Detailed results provide insight into the function of secondary fractures as an immobile domain affecting mass transfer on time scales relevant to

  10. An Update of the Analytical Groundwater Modeling to Assess Water Resource Impacts at the Afton Solar Energy Zone

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John J. [Argonne National Lab. (ANL), Argonne, IL (United States); Greer, Christopher B. [Argonne National Lab. (ANL), Argonne, IL (United States); Carr, Adrianne E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-10-01

    The purpose of this study is to update a one-dimensional analytical groundwater flow model to examine the influence of potential groundwater withdrawal in support of utility-scale solar energy development at the Afton Solar Energy Zone (SEZ) as a part of the Bureau of Land Management’s (BLM’s) Solar Energy Program. This report describes the modeling for assessing the drawdown associated with SEZ groundwater pumping rates for a 20-year duration considering three categories of water demand (high, medium, and low) based on technology-specific considerations. The 2012 modeling effort published in the Final Programmatic Environmental Impact Statement for Solar Energy Development in Six Southwestern States (Solar PEIS; BLM and DOE 2012) has been refined based on additional information described below in an expanded hydrogeologic discussion.

  11. Isotope Investigations of Groundwater Movement in a Coarse Gravel Unsaturated Zone

    Energy Technology Data Exchange (ETDEWEB)

    Mali, N. [Geological Survey of Slovenia, Department of Hydrogeology, Ljubljana (Slovenia); Kozar-Logar, J. [Jozef Stefan Institute, Ljubljana (Slovenia); Leis, A. [Institute of Water Resources Management, Hydrogeology and Geophysics, Joanneum Research Forschungsgesellschaft mbH, Graz (Austria)

    2013-07-15

    The unsaturated zone above an aquifer serves as a water reservoir which discharges water and possible pollution to the saturated zone. This paper presents the application of oxygen-18 and tritium isotope methods in the study of groundwater transport processes in the unsaturated zone of Selniska Dobrava coarse gravel aquifer. The Selniska Dobrava gravel aquifer is an important water resource for Maribor and its surroundings, therefore the determination of transport processes in the unsaturated zone is important regarding its protection. Groundwater flow characteristics were estimated using isotopes and based on experimental work in a lysimeter. Tritium investigation results were compared with the results of long term oxygen-18 isotope investigation. In this paper the analytical approach, results and interpretation of {delta}{sup 18}O and tritium measurements in the unsaturated zone are presented. (author)

  12. Groundwater Hydrochemical Zoning in Inland Plains and its Genetic Mechanisms

    Directory of Open Access Journals (Sweden)

    Liting Xing

    2018-06-01

    Full Text Available Pore water in inland plain areas, generally having poor water quality, contain complex hydrochemical properties. In order to examine groundwater chemical composition formation characteristics, groundwater in the Jiyang area of Lubei Plain was studied using stratified monitoring of drilling, analysis of water level and water quality, isotope analysis, ion ratio coefficient and isothermal adsorption experiments, hydrochemical characteristics, and analysis of variations in different shallow depths. Results show that: (1 Numerous hydrochemistry types are present in the diving. Along with the direction of groundwater flow, total dissolved solids (TDS of diving in the study area generally increases and the hydrochemical type changes from the HCO3 type to the HCO3·SO4 type, Cl·HCO3 type and the Cl·SO4 type. (2 Shallow brackish water and freshwater in the horizontal direction are alternately distributed, and shallow brackish water is distributed in the area between old channels, showing sporadic spots or bands, whose hydrochemistry type is predominantly Cl·SO4-Na·Mg·Ca. (3 Affected by the sedimentary environment, hydrodynamic conditions and other factors; diving, middle brackish water and deep freshwater are vertically deposited in the study area. The dynamics of middle brackish water quality are stable due to the sedimentary environment and clay deposits. The hydrochemistry types of middle brackish water are mainly Cl·SO4-Mg·Na and SO4·Cl-Na·Mg, while the deep confined water is dominated by HCO3. (4 The optimal adsorption isotherms of Na+, Ca2+ and Mg2+ in groundwater from clay, with a thickness raging from 6–112 m, conformed to the Henry equation and the Langmuir equation. The retardation of Na+, Ca2+ and Mg2+ in groundwater differed with differing depths of the clay deposit. The trend of change in retardation strength correlates strongly with the TDS of groundwater. Groundwater in the inland plain area is affected by complicated

  13. Groundwater chemistry of shallow aquifers in the coastal zones of Cochin, India

    Digital Repository Service at National Institute of Oceanography (India)

    Laluraj, C.M.; Gopinath, G.; DineshKumar, P.K.

    Laluraj et al.: Groundwater chemistry of shallow aquifers - 133 - APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 3(1): 133-139. http://www.ecology.kee.hu ● ISSN 1589 1623  2005, Penkala Bt., Budapest, Hungary GROUNDWATER CHEMISTRY OF SHALLOW AQUIFERS... post monsoon (November 2003) in the coastal zones of Cochin. Laluraj et al.: Groundwater chemistry of shallow aquifers - 134 - APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 3(1): 133-139. http://www.ecology.kee.hu ● ISSN 1589 1623  2005, Penkala...

  14. Groundwater composition fluctuation within technogenic zones (case study: flooded coal mines in Primorsky Krai, Russia)

    Science.gov (United States)

    Tarasenko, I. A.; Zinkov, A. V.; Vakh, E. A.; Vetoshkina, A. V.; Strelnikova, A. B.

    2016-03-01

    The paper considers groundwater composition fluctuation within technogenic zones based on evidence from the flooded coal mines of Primorye. The authors have determined the regularities of hydrogeochemical processes, specified the groundwater composition fluctuation within the technogenic complexes located in the liquidated mine areas, and identified the equilibrium phases between the studied waters and specific secondary minerals. It has been proved that water within natural-technogenic complexes in the liquidated mine areas are saturated with silicates, carbonates, sulfates, oxides, and hydroxides, which should be taken into account when designing technologies for groundwater treatment.

  15. Radon concentration distributions in shallow and deep groundwater around the Tachikawa fault zone.

    Science.gov (United States)

    Tsunomori, Fumiaki; Shimodate, Tomoya; Ide, Tomoki; Tanaka, Hidemi

    2017-06-01

    Groundwater radon concentrations around the Tachikawa fault zone were surveyed. The radon concentrations in shallow groundwater samples around the Tachikawa fault segment are comparable to previous studies. The characteristics of the radon concentrations on both sides of the segment are considered to have changed in response to the decrease in groundwater recharge caused by urbanization on the eastern side of the segment. The radon concentrations in deep groundwater samples collected around the Naguri and the Tachikawa fault segments are the same as those of shallow groundwater samples. However, the radon concentrations in deep groundwater samples collected from the bedrock beside the Naguri and Tachikawa fault segments are markedly higher than the radon concentrations expected from the geology on the Kanto plane. This disparity can be explained by the development of fracture zones spreading on both sides of the two segments. The radon concentration distribution for deep groundwater samples from the Naguri and the Tachikawa fault segments suggests that a fault exists even at the southern part of the Tachikawa fault line. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Identification of groundwater prospective zones by using remote ...

    Indian Academy of Sciences (India)

    remote sensing and geoelectrical methods in Jharia and. Raniganj coalfields, Dhanbad district, Jharkhand state. Basudeo Rai. 1,∗ ... are most promising for groundwater exploration and dug wells may be dug up to depths of. 30 ± 5 m. 1. ..... Gupta A 1980 Correlation of Landsat and airborne magnetic anomaly data of a part ...

  17. Hydrological mediated denitrification in groundwater below a seasonal flooded restored riparian zone

    DEFF Research Database (Denmark)

    Jensen, Jannick Kolbjørn; Engesgaard, Peter; Johnsen, Anders R.

    2017-01-01

    nitrate removal in groundwater primarily by two mechanisms. First, by creating a stagnant flow zone beneath the flooded area thereby increasing the residence time and leaving more time for nitrate removal. Secondly, nitrate removal is increased by enhancing upward flow into the highly reactive organic......A restored riparian zone was characterized to understand the effects of flooding on subsurface hydrological flow paths and nitrate removal in groundwater. Field and laboratory investigations were combined with numerical modeling of dynamic flow and reactive nitrate transport. Flooding enhances...

  18. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    Science.gov (United States)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only

  19. Unsaturated-zone fast-path flow calculations for Yucca Mountain groundwater travel time analyses (GWTT-94)

    International Nuclear Information System (INIS)

    Arnold, B.W.; Altman, S.J.; Robey, T.H.

    1995-08-01

    Evaluation of groundwater travel time (GWTT) is required as part of the investigation of the suitability of Yucca Mountain as a potential high-level nuclear-waste repository site. The Nuclear Regulatory Commission's GWTT regulation is considered to be a measure of the intrinsic ability of the site to contain radionuclide releases from the repository. The work reported here is the first step in a program to provide an estimate of GWTT at the Yucca Mountain site in support of the DOE's Technical Site Suitability and as a component of a license application. Preliminary estimation of the GWTT distribution in the unsaturated zone was accomplished using a numerical model of the physical processes of groundwater flow in the fractured, porous medium of the bedrock. Based on prior investigations of groundwater flow at the site, fractures are thought to provide the fastest paths for groundwater flow; conditions that lead to flow in fractures were investigated and simulated. Uncertainty in the geologic interpretation of Yucca Mountain was incorporated through the use of geostatistical simulations, while variability of hydrogeologic parameters within each unit was accounted for by the random sampling of parameter probability density functions. The composite-porosity formulation of groundwater flow was employed to simulate flow in both the matrix and fracture domains. In this conceptualization, the occurrence of locally saturated conditions within the unsaturated zone is responsible for the initiation of fast-path flow through fractures. The results of the GWTT-94 study show that heterogeneity in the hydraulic properties of the model domain is an important factor in simulating local regions of high groundwater saturation. Capillary-pressure conditions at the surface boundary influence the extent of the local saturation simulated

  20. Potential effects of the Hawaii Geothermal Project on ground-water resources on the island of Hawaii

    Science.gov (United States)

    Sorey, M.L.; Colvard, E.M.

    1994-01-01

    In 1990, the State of Hawaii proposed the Hawaii Geothermal Project for the development of as much as 500 MW of electric power from the geothermal system in the East Rift Zone of Kilauea Volcano. This report uses data from 31 wells and 8 springs to describe the properties of the ground-water system in and adjacent to the East Rift Zone. Potential effects of this project on ground-water resources are also discussed. Data show differences in ground-water chemistry and heads within the study area that appear to be related to mixing of waters of different origins and ground-water impoundment by volcanic dikes. East of Pahoa, the ground-water system within the rift is highly transmissive and receives abundant recharge from precipitation; therefore, the pumping of freshwater to support geothermal development in that part of the rift zone would have a minimal effect on ground-water levels. To the southwest of Pahoa, dike impoundment reduces the transmissivity of the ground-water system to such an extent that wells might not be capable of supplying sufficient fresh water to support geothermal operations. Contamination of ground-water resources by accidental release of geothermal fluids into shallow aquifers is possible because of corrosive conditions in the geothermal wells, potential well blowouts, and high ground-water velocities in parts of the region. Hydrologic monitoring of water level, temperature, and chemistry in observation wells should continue throughout development of geothermal resources for the Hawaii Geothermal Project for early detection of leakage and migration of geothermal fluids within the groundwater system.

  1. Potential for saturated ground-water system contamination at the Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Stone, R.; Ruggieri, M.R.; Rogers, L.L.; Emerson, D.O.; Buddemeier, R.W.

    1982-01-01

    A program of hydrogeologic investigation has been carried out to determine the likelihood of contaminant movement to the saturated zone from near the ground surface at Lawrence Livermore National Laboratory (LLNL). A companion survey of potential contaminant sources was also conducted at the LLNL. Water samples from selected LLNL wells were analyzed to test the water quality in the uppermost part of the saturated zone, which is from 14 to 48 m (45 to 158 ft) beneath the surface. Only nitrate and tritium were found in concentrations above natural background. In one well, the nitrate was slightly more concentrated than the drinking water limit. The nitrate source has not been found. The tritium in all ground-water samples from wells was found far less concentrated than the drinking water limit. The extent of infiltration of surface water was traced with environmental tritium. The thickness and stratigraphy of the unsaturated zone beneath the LLNL, and nearby area, was determined with specially constructed wells and boreholes. Well hydrograph analysis indicated where infiltration of surface water reached the saturated ground-water system. The investigation indicates that water infiltrating from the surface, through alluvial deposits, reaches the saturated zone along the course of Arroyo Seco, Arroyo Las Positas, and from the depression near the center of the site where seasonal water accumulates. Several potential contaminant sources were identified, and it is likely that contaminants could move from near the ground surface to the saturated zone beneath LLNL. Additional ground-water sampling and analysis will be performed and ongoing investigations will provide estimates of the speed with which potential contaminants can flow laterally in the saturated zone beneath LLNL. 34 references, 61 figures, 16 tables

  2. TECHNICAL BASIS FOR EVALUATING SURFACE BARRIERS TO PROTECT GROUNDWATER FROM DEEP VADOSE ZONE CONTAMINATION

    International Nuclear Information System (INIS)

    Fayer, J.M.; Freedman, V.L.; Ward, A.L.; Chronister, G.B.

    2010-01-01

    The U.S. DOE and its predecessors released nearly 2 trillion liters (450 billion gallons) of contaminated liquid into the vadose zone at the Hanford Site. Some of the contaminants currently reside in the deeper parts of the vadose zone where they are much less accessible to characterization, monitoring, and typical remediation activities. The DOE Richland Operations Office (DOE-RL) prepared a treatability test plan in 2008 to examine remediation options for addressing contaminants in the deep vadose zone; one of the technologies identified was surface barriers (also known as engineered barriers, covers, and caps). In the typical configuration, the contaminants are located relatively close to the surface, generally within 15 m, and thus they are close to the base of the surface barrier. The proximity of the surface barrier under these conditions yielded few concerns about the effectiveness of the barrier at depth, particularly for cases in which the contaminants were in a lined facility. At Hanford, however, some unlined sites have contaminants located well below depths of 15 m. The issue raised about these sites is the degree of effectiveness of a surface barrier in isolating contaminants in the deep vadose zone. Previous studies by Hanford Site and PNNL researchers suggest that surface barriers have the potential to provide a significant degree of isolation of deep vadose zone contaminants. The studies show that the actual degree of isolation is site-specific and depends on many factors, including recharge rates, barrier size, depth of contaminants, geohydrologic properties ofthe sediments, and the geochemical interactions between the contaminants and the sediments. After the DOE-RL treatability test plan was published, Pacific Northwest National Laboratory was contracted to review the information available to support surface barrier evaluation for the deep vadose zone, identify gaps in the information and outcomes necessary to fill the data gaps, and outline

  3. Aquifers and hyporheic zones: Towards an ecological understanding of groundwater

    Science.gov (United States)

    Hancock, Peter J.; Boulton, Andrew J.; Humphreys, William F.

    2005-03-01

    Ecological constraints in subsurface environments relate directly to groundwater flow, hydraulic conductivity, interstitial biogeochemistry, pore size, and hydrological linkages to adjacent aquifers and surface ecosystems. Groundwater ecology has evolved from a science describing the unique subterranean biota to its current form emphasising multidisciplinary studies that integrate hydrogeology and ecology. This multidisciplinary approach seeks to elucidate the function of groundwater ecosystems and their roles in maintaining subterranean and surface water quality. In aquifer-surface water ecotones, geochemical gradients and microbial biofilms mediate transformations of water chemistry. Subsurface fauna (stygofauna) graze biofilms, alter interstitial pore size through their movement, and physically transport material through the groundwater environment. Further, changes in their populations provide signals of declining water quality. Better integrating groundwater ecology, biogeochemistry, and hydrogeology will significantly advance our understanding of subterranean ecosystems, especially in terms of bioremediation of contaminated groundwaters, maintenance or improvement of surface water quality in groundwater-dependent ecosystems, and improved protection of groundwater habitats during the extraction of natural resources. Overall, this will lead to a better understanding of the implications of groundwater hydrology and aquifer geology to distributions of subsurface fauna and microbiota, ecological processes such as carbon cycling, and sustainable groundwater management. Les contraintes écologiques dans les environnements de subsurface sont en relation directe avec les écoulements des eaux souterraines, la conductivité hydraulique, la biogéochimie des milieux interstitiels, la taille des pores, et les liens hydrologiques avec les aquifères et les écosystèmes adjacents. L'écologie des eaux souterraines a évolué d'une science décrivant uniquement les

  4. Decomposition of groundwater level fluctuations using transfer modelling in an area with shallow to deep unsaturated zones

    Science.gov (United States)

    Gehrels, J. C.; van Geer, F. C.; de Vries, J. J.

    1994-05-01

    Time series analysis of the fluctuations in shallow groundwater levels in the Netherlands lowlands have revealed a large-scale decline in head during recent decades as a result of an increase in land drainage and groundwater withdrawal. The situation is more ambiguous in large groundwater bodies located in the eastern part of the country, where the unsaturated zone increases from near zero along the edges to about 40 m in the centre of the area. As depth of the unsaturated zone increases, groundwater level reacts with an increasing delay to fluctuations in climate and influences of human activities. The aim of the present paper is to model groundwater level fluctuations in these areas using a linear stochastic transfer function model, relating groundwater levels to estimated precipitation excess, and to separate artificial components from the natural groundwater regime. In this way, the impact of groundwater withdrawal and the reclamation of a 1000 km 2 polder area on the groundwater levels in the adjoining higher ground could be assessed. It became evident that the linearity assumption of the transfer functions becomes a serious drawback in areas with the deepest groundwater levels, because of non-linear processes in the deep unsaturated zone and the non-synchronous arrival of recharge in the saturated zone. Comparison of the results from modelling the influence of reclamation with an analytical solution showed that the lowering of groundwater level is partly compensated by reduced discharge and therefore is less than expected.

  5. Potential effects of the Hawaii geothermal project on ground-water resources on the Island of Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Sorey, M.L.; Colvard, E.M.

    1994-07-01

    This report provides data and information on the quantity and quality of ground-water resources in and adjacent to proposed geothermal development areas on the Island of Hawaii Geothermal project for the development of as much as 500 MW of electric power from the geothermal system in the East Rift Zone of Kilauea Volcano. Data presented for about 31 wells and 8 springs describe the chemical, thermal, and hydraulic properties of the ground-water system in and adjacent to the East Rift Zone. On the basis of this information, potential effects of this geothermal development on drawdown of ground-water levels and contamination of ground-water resources are discussed. Significant differences in ground-water levels and in the salinity and temperature of ground water within the study area appear to be related to mixing of waters from different sources and varying degrees of ground-water impoundment by volcanic dikes. Near Pahoa and to the east, the ground-water system within the rift is highly transmissive and receives abundant recharge from precipitation; therefore, the relatively modest requirements for fresh water to support geothermal development in that part of the east rift zone would result in minimal effects on ground-water levels in and adjacent to the rift. To the southwest of Pahoa, dike impoundment reduces the transmissivity of the ground-water system to such an extent that wells might not be capable of supplying fresh water at rates sufficient to support geothermal operations. Water would have to be transported to such developments from supply systems located outside the rift or farther downrift. Contaminant migration resulting from well accidents could be rapid because of relatively high ground-water velocities in parts of the region. Hydrologic monitoring of observation wells needs to be continued throughout development of geothermal resources for the Hawaii Geothermal Project to enable the early detection of leakage and migration of geothermal fluids.

  6. Persistence of uranium groundwater plumes: Contrasting mechanisms at two DOE sites in the groundwater-river interaction zone

    Science.gov (United States)

    Zachara, John M.; Long, Philip E.; Bargar, John; Davis, James A.; Fox, Patricia; Fredrickson, Jim K.; Freshley, Mark D.; Konopka, Allan E.; Liu, Chongxuan; McKinley, James P.; Rockhold, Mark L.; Williams, Kenneth H.; Yabusaki, Steve B.

    2013-04-01

    We examine subsurface uranium (U) plumes at two U.S. Department of Energy sites that are located near large river systems and are influenced by groundwater-river hydrologic interaction. Following surface excavation of contaminated materials, both sites were projected to naturally flush remnant uranium contamination to levels below regulatory limits (e.g., 30 μg/L or 0.126 μmol/L; U.S. EPA drinking water standard), with 10 years projected for the Hanford 300 Area (Columbia River) and 12 years for the Rifle site (Colorado River). The rate of observed uranium decrease was much lower than expected at both sites. While uncertainty remains, a comparison of current understanding suggests that the two sites have common, but also different mechanisms controlling plume persistence. At the Hanford 300 A, the persistent source is adsorbed U(VI) in the vadose zone that is released to the aquifer during spring water table excursions. The release of U(VI) from the vadose zone and its transport within the oxic, coarse-textured aquifer sediments is dominated by kinetically-limited surface complexation. Modeling implies that annual plume discharge volumes to the Columbia River are small (oxidation of naturally reduced, contaminant U(IV) in the saturated zone and a continuous influx of U(VI) from natural, up-gradient sources influence plume persistence. Rate-limited mass transfer and surface complexation also control U(VI) migration velocity in the sub-oxic Rifle groundwater. Flux of U(VI) from the vadose zone at the Rifle site may be locally important, but it is not the dominant process that sustains the plume. A wide range in microbiologic functional diversity exists at both sites. Strains of Geobacter and other metal reducing bacteria are present at low natural abundance that are capable of enzymatic U(VI) reduction in localized zones of accumulated detrital organic carbon or after organic carbon amendment. Major differences between the sites include the geochemical nature of

  7. Persistence of uranium groundwater plumes: contrasting mechanisms at two DOE sites in the groundwater-river interaction zone.

    Science.gov (United States)

    Zachara, John M; Long, Philip E; Bargar, John; Davis, James A; Fox, Patricia; Fredrickson, Jim K; Freshley, Mark D; Konopka, Allan E; Liu, Chongxuan; McKinley, James P; Rockhold, Mark L; Williams, Kenneth H; Yabusaki, Steve B

    2013-04-01

    We examine subsurface uranium (U) plumes at two U.S. Department of Energy sites that are located near large river systems and are influenced by groundwater-river hydrologic interaction. Following surface excavation of contaminated materials, both sites were projected to naturally flush remnant uranium contamination to levels below regulatory limits (e.g., 30 μg/L or 0.126 μmol/L; U.S. EPA drinking water standard), with 10 years projected for the Hanford 300 Area (Columbia River) and 12 years for the Rifle site (Colorado River). The rate of observed uranium decrease was much lower than expected at both sites. While uncertainty remains, a comparison of current understanding suggests that the two sites have common, but also different mechanisms controlling plume persistence. At the Hanford 300 A, the persistent source is adsorbed U(VI) in the vadose zone that is released to the aquifer during spring water table excursions. The release of U(VI) from the vadose zone and its transport within the oxic, coarse-textured aquifer sediments is dominated by kinetically-limited surface complexation. Modeling implies that annual plume discharge volumes to the Columbia River are small (oxidation of naturally reduced, contaminant U(IV) in the saturated zone and a continuous influx of U(VI) from natural, up-gradient sources influence plume persistence. Rate-limited mass transfer and surface complexation also control U(VI) migration velocity in the sub-oxic Rifle groundwater. Flux of U(VI) from the vadose zone at the Rifle site may be locally important, but it is not the dominant process that sustains the plume. A wide range in microbiologic functional diversity exists at both sites. Strains of Geobacter and other metal reducing bacteria are present at low natural abundance that are capable of enzymatic U(VI) reduction in localized zones of accumulated detrital organic carbon or after organic carbon amendment. Major differences between the sites include the geochemical nature of

  8. Brackish groundwater and its potential to augment freshwater supplies

    Science.gov (United States)

    Stanton, Jennifer S.; Dennehy, Kevin F.

    2017-07-18

    Secure, reliable, and sustainable water resources are fundamental to the Nation’s food production, energy independence, and ecological and human health and well-being. Indications are that at any given time, water resources are under stress in selected parts of the country. The large-scale development of groundwater resources has caused declines in the amount of groundwater in storage and declines in discharges to surface water bodies (Reilly and others, 2008). Water supply in some regions, particularly in arid and semiarid regions, is not adequate to meet demand, and severe drought intensifies the stresses affecting water resources (National Drought Mitigation Center, the U.S. Department of Agriculture, and the National Oceanic and Atmospheric Association, 2015). If these drought conditions continue, water shortages could adversely affect the human condition and threaten environmental flows necessary to maintain ecosystem health.In support of the national census of water resources, the U.S. Geological Survey (USGS) completed the national brackish groundwater assessment to provide updated information about brackish groundwater as a potential resource to augment or replace freshwater supplies (Stanton and others, 2017). Study objectives were to consolidate available data into a comprehensive database of brackish groundwater resources in the United States and to produce a summary report highlighting the distribution, physical and chemical characteristics, and use of brackish groundwater resources. This assessment was authorized by section 9507 of the Omnibus Public Land Management Act of 2009 (42 U.S.C. 10367), passed by Congress in March 2009. Before this assessment, the last national brackish groundwater compilation was completed in the mid-1960s (Feth, 1965). Since that time, substantially more hydrologic and geochemical data have been collected and now can be used to improve the understanding of the Nation’s brackish groundwater resources.

  9. Determination of protection zones for Dutch groundwater wells against virus contamination--uncertainty and sensitivity analysis.

    Science.gov (United States)

    Schijven, J F; Mülschlegel, J H C; Hassanizadeh, S M; Teunis, P F M; de Roda Husman, A M

    2006-09-01

    Protection zones of shallow unconfined aquifers in The Netherlands were calculated that allow protection against virus contamination to the level that the infection risk of 10(-4) per person per year is not exceeded with a 95% certainty. An uncertainty and a sensitivity analysis of the calculated protection zones were included. It was concluded that protection zones of 1 to 2 years travel time (206-418 m) are needed (6 to 12 times the currently applied travel time of 60 days). This will lead to enlargement of protection zones, encompassing 110 unconfined groundwater well systems that produce 3 x 10(8) m3 y(-1) of drinking water (38% of total Dutch production from groundwater). A smaller protection zone is possible if it can be shown that an aquifer has properties that lead to greater reduction of virus contamination, like more attachment. Deeper aquifers beneath aquitards of at least 2 years of vertical travel time are adequately protected because vertical flow in the aquitards is only 0.7 m per year. The most sensitive parameters are virus attachment and inactivation. The next most sensitive parameters are grain size of the sand, abstraction rate of groundwater, virus concentrations in raw sewage and consumption of unboiled drinking water. Research is recommended on additional protection by attachment and under unsaturated conditions.

  10. Radiotracer technique to study pollutant behavior in the vadose zone for groundwater protection

    International Nuclear Information System (INIS)

    Kulkarni, U.P.; Sinha, U.K.; Navada, S.V.; Datta, P.S.; Sud, Y.K.; Kulkarni, K.M.; Aggrawal, P.; )

    2004-01-01

    Pollutants are generated either by industrial or agricultural activity. Pollutants produced due to industrial activities fall into point source category and those generated from agricultural are grouped into extended source category. Under an International Atomic Energy Agency/Coordinated Research Program study, emphasis has been given on transport of pollutants, generated from agricultural activities, in particular, due to the application of fertilizer inputs to a variety of crops. Pollutants take entry through the vadose zone and ultimately join the saturated zone. Once groundwater is polluted it is rather difficult or impossible to take remedial measures for groundwater protection. Groundwater being an important natural resource, it is important to protect it from getting polluted. It is hence essential to have a clear understanding of the complex processes (physical, biological and chemical etc.) undergoing in the unsaturated zone. Radiotracers give good insight about the pollutant behavior in the vadose zone. Tritiated water and 60 Co (a gamma emitting tracer in the cyanide complex form) were used as tracers and were injected at 60 cm depth in the vadose zone of IARI farm for pollutant transport study. Tritium and 60 Co tracer displacements were measured by liquid scintillation and sodium iodide scintillation method respectively. It was found that the tritium tracer moved up to 2.4 meters in six months and part of the tritium tracer was exchanged with immobile water in the soil, as three distinct peaks were observed in tritium profile. 60 Co and tritium tracers were found to move with the same velocity in the vadose zone. These tracer studies indicate that the pollutants may reach the groundwater in about three years. (author)

  11. Groundwater quality for irrigation of deep aquifer in southwestern zone of Bangladesh

    Directory of Open Access Journals (Sweden)

    Mirza A.T.M. Tanvir Rahman

    2012-07-01

    Full Text Available In coastal regions of Bangladesh, sources of irrigation are rain, surface and groundwater. Due to rainfall anomaly andsaline contamination, it is important to identify deep groundwater that is eligible for irrigation. The main goal of the study wasto identify deep groundwater which is suitable for irrigation. Satkhira Sadar Upazila, at the southwestern coastal zone ofBangladesh, was the study area, which was divided into North, Center and South zones. Twenty samples of groundwaterwere analyzed for salinity (0.65-4.79 ppt, sodium absorption ratio (1.14-11.62, soluble sodium percentage (32.95-82.21, electricalconductivity (614-2082.11 μS/cm, magnesium adsorption ratio (21.96-26.97, Kelly’s ratio (0.48-4.62, total hardness(150.76-313.33 mg/l, permeability index (68.02-94.16 and residual sodium bi-carbonate (79.68-230.72 mg/l. Chemical constituentsand values were compared with national and international standards. Northern deep groundwater has the highest salinityand chemical concentrations. Salinity and other chemical concentrations show a decreasing trend towards the south. Lowchemical concentrations in the southern region indicate the best quality groundwater for irrigation.

  12. An assessment of groundwater potential and vulnerability in the Upper Manyame Sub-Catchment of Zimbabwe

    Science.gov (United States)

    Misi, Alfred; Gumindoga, Webster; Hoko, Zvikomborero

    2018-06-01

    Severe depletion and pollution of groundwater resources are of rising concern in the Upper Manyame Sub-Catchment (UMSC); Zimbabwe's most urbanised sub-catchment. Despite groundwater playing a pivotal role in the provision of potable water in the sub-catchment, it is under serious threat from anthropogenic stressors which include sewage effluents and leachates from landfills, among others. Inadequate scientific knowledge pertaining to the spatio-temporal variability of groundwater storage and vulnerability in the UMSC is further compromising its sustainability. Therefore, comprehensive assessments of UMSC's Groundwater Potential (GP) and vulnerability are crucial for its effective management. This study assessed GP and vulnerability in the UMSC using Geographic Information Systems and Remote Sensing techniques. Groundwater conditioning factors: geology, slope, land-use, drainage density, topographic index, altitude, recharge and rainfall were used to develop GP zones. Validation of the GP map was done by correlating estimated GP with historical borehole yields. An assessment of groundwater vulnerability was done at micro-catchment level (Marimba) using the GOD model; a three parameter Index Overlay Model. Marimba is the most urbanised and has the second highest borehole density. It also exhibits similar landuse characteristics as the UMSC. Furthermore, groundwater quality in Marimba was assessed from 15 sampling sites. Fifteen drinking water parameters were analysed based on the standard methods for Water and Wastewater Examination. The potability of groundwater was then assessed by comparing the measured water quality parameters with the Standards Association of Zimbabwe (SAZ) drinking water standards and/or WHO guidelines for drinking water. Repeated Measures ANOVA and Principal Component Analysis (PCA) were used to assess the spatio-temporal variations in groundwater quality and to identify key parameters, respectively. About 72% (2725.9 km2) of the UMSC was

  13. Qualitative zoning of groundwater for drinking purposes in Lenjan plain using GQI method through GIS

    Directory of Open Access Journals (Sweden)

    Amin Mohebbi Tafreshi

    2017-09-01

    Full Text Available Background: A new method has been presented specifically for zoning the quality of groundwater for drinking purposes; this method is the groundwater quality index (GQI method. The present research used the GQI method to qualitatively zoning of the Lenjan groundwater for drinking purposes. Methods: Three phases were applied in this research. In the first phase, working on the quality data of 38 wells within the studied plain, the raster map of quality concentration parameters, including pH, TDS, Cl, SO4, Ca, Mg, and Na parameters, was provided by interpolation using the kriging method in the ArcGIS software. In the second phase, the mentioned maps were standardized so that various bits of data can follow a common standard and scale. In the third phase, weight was applied to each standardized map, and ultimately the classification map for each parameter was drawn. The final GQI map was created by combining the mentioned classification maps. Results: The GQI values for Lenjan plain were rated from the minimum (67.48 to the maximum (90.05. The results showed an average to acceptable level of quality for drinking water. Conclusion: According to the final map, the central and southern parts of Lenjan plain, which have acceptable GQI rankings, are the best zones from which to use groundwater for drinking purposes.

  14. Hydrodynamic analysis of potential groundwater extraction capacity increase: case study of 'Nelt' groundwater source at Dobanovci

    Directory of Open Access Journals (Sweden)

    Bajić Dragoljub I.

    2017-01-01

    Full Text Available A comprehensive hydrodynamic analysis of the groundwater regime undertaken to assess the potential for expanding the 'Nelt' groundwater source at Dobanovci, or developing a new groundwater source for a future baby food factory, including the quantification of the impact on the production wells of the nearby 'Pepsi' groundwater source, is presented in the paper. The existing Nelt source is comprised of three active production wells that tap a subartesian aquifer formed in sands and gravelly sands; however, the analysis considers only the two nearest wells. A long-term group pumping test was con-ducted of production wells N-1 and N2 (Nelt source and production wells B-1 and B-2 (Pepsi source, while the piezometric head in the vicinity of these wells was monitored at observation well P-1, which is located in the area considered for Nelt source expansion. Data were collected at maximum pumping capacity of all the production wells. A hydrodynamic model of groundwater flow in the extended area of the Nelt source was generated for the purposes of the comprehensive hydrodynamic analysis. Hydrodynamic prognostic calculations addressed two solution alternatives for the capacity increase over a period of ten years. Licensed Visual MODFLOW Pro software, deemed to be at the very top in this field, was used for the calculations.

  15. Potential contamination of groundwater in the World Heritage Site of ...

    African Journals Online (AJOL)

    The rapid population growth, high levels of tourism and poor sewage waste disposal (at least for the foreseeable future) in St. Katherine have resulted in potential contamination of groundwater and subsequent high risk to human health. To evaluate the safety of well water for human use in St. Katherine, water samples were ...

  16. GIS-based bivariate statistical techniques for groundwater potential ...

    Indian Academy of Sciences (India)

    Ali Haghizadeh

    2017-11-23

    Nov 23, 2017 ... regions. This study shows the potency of two GIS-based data driven ... growth of these tools has also prepared another ..... Urban. 30467. 3. 0.06. 0.20. 0.74. 0.80. −0.64. Distance from road ..... and artificial neural networks for potential groundwater .... ping: A case study at Mehran region, Iran; Catena 137.

  17. Evaluation of groundwater resource potential in rural part of ...

    African Journals Online (AJOL)

    This study was carried out to determine groundwater potential in the rural area of Northcentral Nigeria using Vertical Electrical Sounding (VES). The VES data was generated from twenty (20) locations in the study area and was later processed and analyzed using IPI2 WIN software. The underlying geo-electric sections ...

  18. Investigation of groundwater flow potential in Makurdi, North Central ...

    African Journals Online (AJOL)

    hp

    Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria. Received 6 August, 2015; ... order to study the groundwater flow potential in Makurdi, north central Nigeria. This was done in thirty .... 600 m above sea level. The drainage consists ..... engineering Studies: A Practical Guide to 2D and 3D Surveys.

  19. Integration of ground-water and vadose-zone geochemistry to investigate hydrochemical evolution

    International Nuclear Information System (INIS)

    Fisher, R.S.; Mullican, W.F.

    1990-01-01

    This paper summarizes the results of an extensive groundwater-sampling program conducted in the Hueco Bolson and Diablo Plateau area of West Texas. The origin, hydrochemical evolution, and age of groundwater in arid lands of Trans-Pecos Texas were investigated by combining mineralogic analyses of soils and aquifer matrix, chemical analyses of readily soluble materials in soils and water extracted from the thick, unsaturated zone, and chemical and isotopic analyses of groundwater from three principal aquifers, the Diablo Plateau, Hueco Bolson, and Rio Grande alluvial aquifers. Repeated groundwater sampling over a 3-year period and quarterly sampling of selected wells revealed no significant short-term chemical or isotopic variability. Groundwater ages range from recent to nearly 28,000 years; the distribution of ages reflects relative permeability (transmissivity) of the aquifers. Most groundwaters evolve from calcium-bicarbonate to sodium-sulfate types because of carbonate and sulfate mineral dissolution coupled with exchange of aqueous calcium and magnesium for sodium on clay minerals. Water in the Rio Grande alluvial aquifer evolved to a sodium-chloride type as a result of extensive evapotranspiration on irrigated fields. The appendices list detailed results of field measurements of temperature, pH, Eh, dissolved oxygen, and major ion concentrations

  20. Nitrate removal in a restored riparian groundwater system: functioning and importance of individual riparian zones

    Directory of Open Access Journals (Sweden)

    S. Peter

    2012-11-01

    Full Text Available For the design and the assessment of river restoration projects, it is important to know to what extent the elimination of reactive nitrogen (N can be improved in the riparian groundwater. We investigated the effectiveness of different riparian zones, characterized by a riparian vegetation succession, for nitrate (NO3 removal from infiltrating river water in a restored and a still channelized section of the river Thur, Switzerland. Functional genes of denitrification (nirS and nosZ were relatively abundant in groundwater from willow bush and mixed forest dominated zones, where oxygen concentrations remained low compared to the main channel and other riparian zones. After flood events, a substantial decline in NO3 concentration (> 50% was observed in the willow bush zone but not in the other riparian zones closer to the river. In addition, the characteristic enrichment of 15N and 18O in the residual NO3 pool (by up to 22‰ for δ15N and up to 12‰ for δ18O provides qualitative evidence that the willow bush and forest zones were sites of active denitrification and, to a lesser extent, NO3 removal by plant uptake. Particularly in the willow bush zone during a period of water table elevation after a flooding event, substantial input of organic carbon into the groundwater occurred, thereby fostering post-flood denitrification activity that reduced NO3 concentration with a rate of ~21 μmol N l−1 d−1. Nitrogen removal in the forest zone was not sensitive to flood pulses, and overall NO3 removal rates were lower (~6 μmol l−1 d−1. Hence, discharge-modulated vegetation–soil–groundwater coupling was found to be a key driver for riparian NO3 removal. We estimated that

  1. Review of ground-water flow and transport models in the unsaturated zone

    Energy Technology Data Exchange (ETDEWEB)

    Oster, C.A.

    1982-11-01

    Models of partially saturated flow and transport in porous media have application in the analysis of existing as well as future low-level radioactive waste facilities located above the water table. An extensive literature search along with telephone and mail correspondence with recognized leading experts in the field, was conducted to identify computer models suitable for studies of low-level radioactive waste facilities located in the unsaturated zone. Fifty-five existing models were identified as potentially useful. Ten of these models were selected for further examination. This report contains a statement of the ground-water flow-contaminant transport problem, a discussion of those methods used to reduce the physical problem to a computer model, a brief discussion about the data requirements of these models. The procedure used to select the ten codes for further discussion is given, along with a list of these models. Finally, the Appendices contain the data about the fifty-five codes examined. Specifically Appendix D contains the detailed discussion of each of the ten selected codes. Included in each discussion are such items which a potential user requires in determining whether the code is suitable for his applications. Appendix E contains brief summary information about each of the fifty-five codes. Included in the summaries are identification data, authors, pertinent references, and model type.

  2. Review of ground-water flow and transport models in the unsaturated zone

    International Nuclear Information System (INIS)

    Oster, C.A.

    1982-11-01

    Models of partially saturated flow and transport in porous media have application in the analysis of existing as well as future low-level radioactive waste facilities located above the water table. An extensive literature search along with telephone and mail correspondence with recognized leading experts in the field, was conducted to identify computer models suitable for studies of low-level radioactive waste facilities located in the unsaturated zone. Fifty-five existing models were identified as potentially useful. Ten of these models were selected for further examination. This report contains a statement of the ground-water flow-contaminant transport problem, a discussion of those methods used to reduce the physical problem to a computer model, a brief discussion about the data requirements of these models. The procedure used to select the ten codes for further discussion is given, along with a list of these models. Finally, the Appendices contain the data about the fifty-five codes examined. Specifically Appendix D contains the detailed discussion of each of the ten selected codes. Included in each discussion are such items which a potential user requires in determining whether the code is suitable for his applications. Appendix E contains brief summary information about each of the fifty-five codes. Included in the summaries are identification data, authors, pertinent references, and model type

  3. Groundwater potential prediction by using geoelectricity method a case study in Simpang Lima and around it

    Science.gov (United States)

    Rahmawati, D. R.; Supriyadi; Aryani, N. P.; Naufal, M. A.

    2018-03-01

    Water is an important natural resource, which is available both on surface as well as in recharge zone of weathered layer and in various other suitable water reservoir formations/structures below the surface. The study was conducted in Semarang City, Indonesian. Simpang Lima area were chosen since they have geology record of thick alluvium. The condition of Simpang Lima and around it which currently has developed into the main business area in Semarang City. This is marked by the presence like hotels, super market, that is more than one. This condition certainly requires a supply of water for various purposes that support economic efforts in the region. During this time the water needs are met by drilling wells and used as much as possible without taking into account the impact of water utilization. This study aims to determine the zones that have the potential existence of groundwater. The method used is Geoelectric method with Shlumberger configuration in 7 distributed spatial point. The results showed that there is a potential groundwater in eastern Pekunden, Erlanga, behind The Hotel Horizon, and Simpang Lima. Groundwater is found successively at an average depth of 15 meters under earth’s surface.

  4. Assessing Contamination Potential of Nitrate-N in Groundwater of Lanyang Plain

    Science.gov (United States)

    Liang, Ching-Ping; Tu, Yu-Lin; Lin, Chien-Wen; Jang, Cheng-Shin

    2013-04-01

    Nitrate-N pollution is often relevant to agricultural activities such as the fertilization of crops. Significant increases in the nitrate-N pollution of groundwater are found in natural recharging zones of Taiwan. The increasing nitrate-N contamination seriously threatens public drinking water supply and human health. Constructing a correct map of aquifer contamination potential is an effective and feasible way to protect groundwater for quality assessment and management. Therefore, in this study, we use DRASTIC model with the help of geographic information system (GIS) to assess and predict the contamination potential of nitrate-N in the aquifer of Lanyang Plain, Taiwan. Seven factors of hydrogeology and hydrology, which includes seven parameters - Depth to groundwater, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity, are considered to carry out this assessment. The validity of the presented model is established by comparing the results with the measured nitrate concentration in wells within the study area. Adjusting factor weightings via the discriminant analysis is performed to improve the assessment and prediction. The analyzed results can provide residents with suggestive strategies against nitrate-N pollution in agricultural regions and government administrators with explicit information of Nitrate-N pollution extents when plans of water resources are considered.

  5. 32 CFR 256.7 - Accident potential zone guidelines.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Accident potential zone guidelines. 256.7 Section 256.7 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS AIR INSTALLATIONS COMPATIBLE USE ZONES § 256.7 Accident potential zone guidelines...

  6. Response to recharge variation of thin rainwater lenses and their mixing zone with underlying saline groundwater

    Directory of Open Access Journals (Sweden)

    S. Eeman

    2012-10-01

    Full Text Available In coastal zones with saline groundwater, fresh groundwater lenses may form due to infiltration of rain water. The thickness of both the lens and the mixing zone, determines fresh water availability for plant growth. Due to recharge variation, the thickness of the lens and the mixing zone are not constant, which may adversely affect agricultural and natural vegetation if saline water reaches the root zone during the growing season. In this paper, we study the response of thin lenses and their mixing zone to variation of recharge. The recharge is varied using sinusoids with a range of amplitudes and frequencies. We vary lens characteristics by varying the Rayleigh number and Mass flux ratio of saline and fresh water, as these dominantly influence the thickness of thin lenses and their mixing zone. Numerical results show a linear relation between the normalised lens volume and the main lens and recharge characteristics, enabling an empirical approximation of the variation of lens thickness. Increase of the recharge amplitude causes increase and the increase of recharge frequency causes a decrease in the variation of lens thickness. The average lens thickness is not significantly influenced by these variations in recharge, contrary to the mixing zone thickness. The mixing zone thickness is compared to that of a Fickian mixing regime. A simple relation between the travelled distance of the centre of the mixing zone position due to variations in recharge and the mixing zone thickness is shown to be valid for both a sinusoidal recharge variation and actual records of daily recharge data. Starting from a step response function, convolution can be used to determine the effect of variable recharge in time. For a sinusoidal curve, we can determine delay of lens movement compared to the recharge curve as well as the lens amplitude, derived from the convolution integral. Together the proposed equations provide us with a first order approximation of lens

  7. Regional variability of nitrate fluxes in the unsaturated zone and groundwater, Wisconsin, USA

    Science.gov (United States)

    Green, Christopher T.; Liao, Lixia; Nolan, Bernard T.; Juckem, Paul F.; Shope, Christopher L.; Tesoriero, Anthony J.; Jurgens, Bryant

    2018-01-01

    Process-based modeling of regional NO3− fluxes to groundwater is critical for understanding and managing water quality, but the complexity of NO3− reactive transport processes make implementation a challenge. This study introduces a regional vertical flux method (VFM) for efficient estimation of reactive transport of NO3− in the vadose zone and groundwater. The regional VFM was applied to 443 well samples in central-eastern Wisconsin. Chemical measurements included O2, NO3−, N2 from denitrification, and atmospheric tracers of groundwater age including carbon-14, chlorofluorocarbons, tritium, and tritiogenic helium. VFM results were consistent with observed chemistry, and calibrated parameters were in-line with estimates from previous studies. Results indicated that (1) unsaturated zone travel times were a substantial portion of the transit time to wells and streams (2) since 1945 fractions of applied N leached to groundwater have increased for manure-N, possibly due to increased injection of liquid manure, and decreased for fertilizer-N, and (3) under current practices and conditions, approximately 60% of the shallow aquifer will eventually be affected by downward migration of NO3−, with denitrification protecting the remaining 40%. Recharge variability strongly affected the unsaturated zone lag times and the eventual depth of the NO3− front. Principal components regression demonstrated that VFM parameters and predictions were significantly correlated with hydrogeochemical landscape features. The diverse and sometimes conflicting aspects of N management (e.g. limiting N volatilization versus limiting N losses to groundwater) warrant continued development of large-scale holistic strategies to manage water quality and quantity.

  8. Regional Variability of Nitrate Fluxes in the Unsaturated Zone and Groundwater, Wisconsin, USA

    Science.gov (United States)

    Green, Christopher T.; Liao, Lixia; Nolan, Bernard T.; Juckem, Paul F.; Shope, Christopher L.; Tesoriero, Anthony J.; Jurgens, Bryant C.

    2018-01-01

    Process-based modeling of regional NO3- fluxes to groundwater is critical for understanding and managing water quality, but the complexity of NO3- reactive transport processes makes implementation a challenge. This study introduces a regional vertical flux method (VFM) for efficient estimation of reactive transport of NO3- in the vadose zone and groundwater. The regional VFM was applied to 443 well samples in central-eastern Wisconsin. Chemical measurements included O2, NO3-, N2 from denitrification, and atmospheric tracers of groundwater age including carbon-14, chlorofluorocarbons, tritium, and tritiogenic helium. VFM results were consistent with observed chemistry, and calibrated parameters were in-line with estimates from previous studies. Results indicated that (1) unsaturated zone travel times were a substantial portion of the transit time to wells and streams, (2) since 1945 fractions of applied N leached to groundwater have increased for manure-N, possibly due to increased injection of liquid manure, and decreased for fertilizer-N, and (3) under current practices and conditions, approximately 60% of the shallow aquifer will eventually be affected by downward migration of NO3-, with denitrification protecting the remaining 40%. Recharge variability strongly affected the unsaturated zone lag times and the eventual depth of the NO3- front. Principal components regression demonstrated that VFM parameters and predictions were significantly correlated with hydrogeochemical landscape features. The diverse and sometimes conflicting aspects of N management (e.g., limiting N volatilization versus limiting N losses to groundwater) warrant continued development of large-scale holistic strategies to manage water quality and quantity.

  9. Evaluating Contaminant Flux from the Vadose Zone to the Groundwater in the Hanford Central Plateau. SX Tank Farms Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Last, George V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tartakovsky, Guzel D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-09-01

    At the DOE Hanford Site, contaminants were discharged to the subsurface through engineered waste sites in the Hanford Central Plateau. Additional waste was released through waste storage tank leaks. Much of the contaminant inventory is still present within the unsaturated vadose zone sediments. The nature and extent of future groundwater contaminant plumes and the growth or decline of current groundwater plumes beneath the Hanford Central Plateau are a function of the contaminant flux from the vadose zone to the groundwater. In general, contaminant transport is slow through the vadose zone and it is difficult to directly measure contaminant flux in the vadose zone. Predictive analysis, supported by site characterization and monitoring data, was applied using a structured, systems-based approach to estimate the future contaminant flux to groundwater in support of remediation decisions for the vadose zone and groundwater (Truex and Carroll 2013). The SX Tank Farm was used as a case study because of the existing contaminant inventory in the vadose zone, observations of elevated moisture content in portions of the vadose zone, presence of a limited-extent groundwater plume, and the relatively large amount and wide variety of data available for the site. Although the SX Tank Farm case study is most representative of conditions at tank farm sites, the study has elements that are also relevant to other types of disposal sites in the Hanford Central Plateau.

  10. The Vertical Flux Method (VFM) for regional estimates of temporally and spatially varying nitrate fluxes in unsaturated zone and groundwater

    Science.gov (United States)

    Green, C. T.; Liao, L.; Nolan, B. T.; Juckem, P. F.; Ransom, K.; Harter, T.

    2017-12-01

    Process-based modeling of regional NO3- fluxes to groundwater is critical for understanding and managing water quality. Measurements of atmospheric tracers of groundwater age and dissolved-gas indicators of denitrification progress have potential to improve estimates of NO3- reactive transport processes. This presentation introduces a regionalized version of a vertical flux method (VFM) that uses simple mathematical estimates of advective-dispersive reactive transport with regularization procedures to calibrate estimated tracer concentrations to observed equivalents. The calibrated VFM provides estimates of chemical, hydrologic and reaction parameters (source concentration time series, recharge, effective porosity, dispersivity, reaction rate coefficients) and derived values (e.g. mean unsaturated zone travel time, eventual depth of the NO3- front) for individual wells. Statistical learning methods are used to extrapolate parameters and predictions from wells to continuous areas. The regional VFM was applied to 473 well samples in central-eastern Wisconsin. Chemical measurements included O2, NO3-, N2 from denitrification, and atmospheric tracers of groundwater age including carbon-14, chlorofluorocarbons, tritium, and triogiogenic helium. VFM results were consistent with observed chemistry, and calibrated parameters were in-line with independent estimates. Results indicated that (1) unsaturated zone travel times were a substantial portion of the transit time to wells and streams (2) fractions of N leached to groundwater have changed over time, with increasing fractions from manure and decreasing fractions from fertilizer, and (3) under current practices and conditions, 60% of the shallow aquifer will eventually be affected by NO3- contamination. Based on GIS coverages of variables related to soils, land use and hydrology, the VFM results at individual wells were extrapolated regionally using boosted regression trees, a statistical learning approach, that related

  11. Economic impacts of urban flooding in South Florida: Potential consequences of managing groundwater to prevent salt water intrusion.

    Science.gov (United States)

    Czajkowski, Jeffrey; Engel, Vic; Martinez, Chris; Mirchi, Ali; Watkins, David; Sukop, Michael C; Hughes, Joseph D

    2018-04-15

    High-value urban zones in coastal South Florida are considered particularly vulnerable to salt water intrusion into the groundwater-based, public water supplies caused by sea level rise (SLR) in combination with the low topography, existing high water table, and permeable karst substrate. Managers in the region closely regulate water depths in the extensive South Florida canal network to control closely coupled groundwater levels and thereby reduce the risk of saltwater intrusion into the karst aquifer. Potential SLR adaptation strategies developed by local managers suggest canal and groundwater levels may have to be increased over time to prevent the increased salt water intrusion risk to groundwater resources. However, higher canal and groundwater levels cause the loss of unsaturated zone storage and lead to an increased risk of inland flooding when the recharge from rainfall exceeds the capacity of the unsaturated zone to absorb it and the water table reaches the surface. Consequently, higher canal and groundwater levels are also associated with increased risk of economic losses, especially during the annual wet seasons. To help water managers and urban planners in this region better understand this trade-off, this study models the relationships between flood insurance claims and groundwater levels in Miami-Dade County. Via regression analyses, we relate the incurred number of monthly flood claims in 16 Miami-Dade County watersheds to monthly groundwater levels over the period from 1996 to 2010. We utilize these estimated statistical relationships to further illustrate various monthly flood loss scenarios that could plausibly result, thereby providing an economic quantification of a "too much water" trade-off. Importantly, this understanding is the first of its kind in South Florida and is exceedingly useful for regional-scale hydro-economic optimization models analyzing trade-offs associated with high water levels. Copyright © 2017 Elsevier B.V. All rights

  12. Modeling of geoelectric parameters for assessing groundwater potentiality in a multifaceted geologic terrain, Ipinsa Southwest, Nigeria - A GIS-based GODT approach

    Science.gov (United States)

    Mogaji, Kehinde Anthony; Omobude, Osayande Bright

    2017-12-01

    Modeling of groundwater potentiality zones is a vital scheme for effective management of groundwater resources. This study developed a new multi-criteria decision making algorithm for groundwater potentiality modeling through modifying the standard GOD model. The developed model christened as GODT model was applied to assess groundwater potential in a multi-faceted crystalline geologic terrain, southwestern, Nigeria using the derived four unify groundwater potential conditioning factors namely: Groundwater hydraulic confinement (G), aquifer Overlying strata resistivity (O), Depth to water table (D) and Thickness of aquifer (T) from the interpreted geophysical data acquired in the area. With the developed model algorithm, the GIS-based produced G, O, D and T maps were synthesized to estimate groundwater potential index (GWPI) values for the area. The estimated GWPI values were processed in GIS environment to produce groundwater potential prediction index (GPPI) map which demarcate the area into four potential zones. The produced GODT model-based GPPI map was validated through application of both correlation technique and spatial attribute comparative scheme (SACS). The performance of the GODT model was compared with that of the standard analytic hierarchy process (AHP) model. The correlation technique results established 89% regression coefficients for the GODT modeling algorithm compared with 84% for the AHP model. On the other hand, the SACS validation results for the GODT and AHP models are 72.5% and 65%, respectively. The overall results indicate that both models have good capability for predicting groundwater potential zones with the GIS-based GODT model as a good alternative. The GPPI maps produced in this study can form part of decision making model for environmental planning and groundwater management in the area.

  13. Unintentional contaminant transfer from groundwater to the vadose zone during source zone remediation of volatile organic compounds.

    Science.gov (United States)

    Chong, Andrea D; Mayer, K Ulrich

    2017-09-01

    Historical heavy use of chlorinated solvents in conjunction with improper disposal practices and accidental releases has resulted in widespread contamination of soils and groundwater in North America and worldwide. As a result, remediation of chlorinated solvents is required at many sites. For source zone treatment, common remediation strategies include in-situ chemical oxidation (ISCO) using potassium or sodium permanganate, and the enhancement of biodegradation by primary substrate addition. It is well known that these remediation methods tend to generate gas (carbon dioxide (CO 2 ) in the case of ISCO using permanganate, CO 2 and methane (CH 4 ) in the case of bioremediation). Vigorous gas generation in the presence of chlorinated solvents, which are categorized as volatile organic contaminants (VOCs), may cause gas exsolution, ebullition and stripping of the contaminants from the treatment zone. This process may lead to unintentional 'compartment transfer', whereby VOCs are transported away from the contaminated zone into overlying clean sediments and into the vadose zone. To this extent, benchtop column experiments were conducted to quantify the effect of gas generation during remediation of the common chlorinated solvent trichloroethylene (TCE/C 2 Cl 3 H). Both ISCO and enhanced bioremediation were considered as treatment methods. Results show that gas exsolution and ebullition occurs for both remediation technologies. Facilitated by ebullition, TCE was transported from the source zone into overlying clean groundwater and was subsequently released into the column headspace. For the case of enhanced bioremediation, the intermediate degradation product vinyl chloride (VC) was also stripped from the treatment zone. The concentrations measured in the headspace of the columns (TCE ∼300ppm in the ISCO column, TCE ∼500ppm and VC ∼1380ppm in the bioremediation column) indicate that substantial transfer of VOCs to the vadose zone is possible. These findings

  14. Ground-water travel time calculations for the potential nuclear repository site at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Younker, J.L.; Wilson, W.E.; Sinnock, S.

    1986-01-01

    In support of the US Department of Energy Nevada Nuclear Waste Storage Investigations Project, ground-water travel times were calculated for flow paths in both the saturated and unsaturated zones at Yucca Mountain, a potential site for a high-level radioactive waste repository in southern Nevada. The calculations were made through a combined effort by Science Applications International Corporation, Sandia National Laboratories, and the US Geological Survey. Travel times in the unsaturated zone were estimated by dividing the flow path length by the ground-water velocity, where velocities were obtained by dividing the vertical flux by the effective porosity of the rock types along assumed vertical flow paths. Saturated zone velocities were obtained by dividing the product of the bulk hydraulic conductivity and hydraulic gradient by the effective porosity. Total travel time over an EPA-established 5-km flow path was then calculated to be the sum of the travel times in the two parts of the flow path. Estimates of ground water fluxes and travel times are critical for evaluating the favorability of the Yucca Mountain site because they provide the basis for estimating the potential for radionuclides to reach the accessible environment within certain time limits

  15. Review of risk from potential emerging contaminants in UK groundwater.

    Science.gov (United States)

    Stuart, Marianne; Lapworth, Dan; Crane, Emily; Hart, Alwyn

    2012-02-01

    This paper provides a review of the types of emerging organic groundwater contaminants (EGCs) which are beginning to be found in the UK. EGCs are compounds being found in groundwater that were previously not detectable or known to be significant and can come from agricultural, urban and rural point sources. EGCs include nanomaterials, pesticides, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well as caffeine and nicotine. Many are relatively small polar molecules which may not be effectively removed by drinking water treatment. Data from the UK Environment Agency's groundwater screening programme for organic pollutants found within the 30 most frequently detected compounds a number of EGCs such as pesticide metabolites, caffeine and DEET. Specific determinands frequently detected include pesticides metabolites, pharmaceuticals including carbamazepine and triclosan, nicotine, food additives and alkyl phosphates. This paper discusses the routes by which these compounds enter groundwater, their toxicity and potential risks to drinking water and the environment. It identifies challenges that need to be met to minimise risk to drinking water and ecosystems. Copyright © 2012. Published by Elsevier B.V.

  16. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    Directory of Open Access Journals (Sweden)

    Jiin-Shuh Jean

    2008-01-01

    Full Text Available Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks. More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surface erosion. This paper suggests 17 antifreeze compounds potentially present in Martian seepage groundwater. Given their liquid state and physical properties, triethylene glycol, diethylene glycol, ethylene glycol, and 1,3-propylene glycol are advanced as the most likely candidate compounds. This paper also explores how a mixing of glycol or glycerol with salts in the Martian seepage groundwater may have lowered water¡¦s freezing point and raised its boiling point, with consequences that created fluid gully and channel erosion. Ethylene glycol and related hydrocarbon compounds have been identified in Martian and other interstellar meteorites. We suggest that these compounds and their proportions to water be included for detection in future explorations.

  17. In Situ Groundwater Denitrification in the Riparian Zone of a Short-Rotation Woody Crop Experimental Watershed

    Science.gov (United States)

    Jeffers, J. B.; Jackson, C. R.; Rau, B.; Pringle, C. M.; Matteson, C.

    2017-12-01

    The southeastern United States has potential to become a major producer of short rotation woody crops (SRWC) for the production of biofuels, but this will require converting to more intensive forest management practices that will increase nitrate (NO3-) loading and alter nitrogen cycling in nearby freshwater ecosystems. Water quality monitoring in an experimental short-rotation woody crop watershed in the Coastal Plain of South Carolina has shown increased concentrations of NO3- in groundwater but no evidence of increased NO3- in riparian groundwater or surface waters. Forested riparian areas established as streamside management zones (SMZ) are known to act as buffers to surface water bodies by mitigating nutrients. The objectives of this study were to quantify denitrification by measuring dinitrogen (N2) and nitrous oxide (N2O) concentrations along groundwater flow paths and analyze relationships between denitrification estimates, nutrients, and water chemistry parameters. A network of piezometers has been established in the Fourmile Experimental Watershed at the Department of Energy - Savannah River Site. Water samples were collected monthly and were analyzed for concentrations of nutrients (temperature, specific conductivity, dissolved oxygen, pH, dissolved organic carbon) and dissolved gases (N2, Ar, N2O). Preliminary data showed greater dissolved N2O concentrations than dissolved N2 concentrations in groundwater. The ratios of N2O to combined end products of denitrification (N2O / N2O+N2) ranged from 0.33 to 0.99. Mean N2O+N2 concentrations were greater in groundwater samples in the SRWC plot and along the SMZ boundary than along the ephemeral stream within the riparian zone. Correlations between water chemistry parameters and N2 concentrations are indicative of known biogeochemical driving factors of denitrification. Continued monthly sampling will be coupled with analysis of nutrient concentrations (NO3-, NH4+, TN) to help determine transport and processing

  18. Natural organics in groundwaters and their potential effect on contaminant transport in granitic rock

    International Nuclear Information System (INIS)

    Vilks, P.; Bachinski, D.B.; Richer, D.

    1996-07-01

    Naturally occurring organics in groundwaters of the Whiteshell Research Area (WRA) of southern Manitoba and of the Atikokan Research Area of northwestern Ontario were investigated to assess their potential role in radionuclide transport within granite fractures of the Canadian Shield. A survey of dissolved organic carbon (DOC) concentrations, carried out to determine the variability in the organic content of these groundwaters, showed average concentrations in WRA deep groundwaters of 0.8 ± 0.1 mg/L for Fracture Zone 2, 0.8 ± 0.4 mg/L for near-vertical fractures, and 2.3 ± 0.8 mg/L for deeper saline groundwater. Surface waters and near-surface groundwaters had significantly higher DOC with 29.2 ± 0.6 mg/L in streams from the East Swamp. The DOC consisted mainly of hydrophilic neutral compounds 60 to 75%, and hydrophobic and hydrophilic acids 23 to 39%, along with very small amounts of hydrophobic bases and neutrals, and hydrophilic bases. The average complexing capacity of natural organics in WRA deep groundwaters was calculated to be 6.7 x 10 -6 eq/L. The ability of these organics to complex radionuclides was tested using conditional stability constants from the literature for humic complex formation with trivalent, tetravalent, pentavalent and hexavalent actinides. The chemistries of Np(V) and U(VI) were predicted to be dominated by inorganic complexes and not significantly affected by organics. Accurate predictions for AM(III) and Th(IV) could not be made since the literature contains a wide range in values of stability constants for humic complexes with these elements. Surface waters and near-surface groundwaters in many areas of the Canadian Shield contain enough humics to complex a significant fraction of dissolved actinides. Radiocarbon ages of humics from WRA groundwater varied between 3600 and 6200 years before present, indicating that a component of humic substances in deep groundwaters must originate from near-surface waters. 54 refs., 15 tabs., 5

  19. Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)

    Science.gov (United States)

    Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.

    2014-01-01

    Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

  20. 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

  1. 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

  2. Climate change impact on groundwater levels in the Guarani Aquifer outcrop zone

    Science.gov (United States)

    Melo, D. D.; Wendland, E.

    2013-12-01

    The unsustainable use of groundwater in many countries might cause water availability restrictions in the future. Such issue is likely to worsen due to predicted climate changes for the incoming decades. As numerous studies suggest, aquifers recharge rates will be affected as a result of climate change. The Guarani Aquifer System (GAS) is one of the most important transboundary aquifer in the world, providing drinkable water for millions of people in four South American countries (Brazil, Argentina, Uruguay and Paraguay). Considering the GAS relevance and how its recharge rates might be altered by climatic conditions anomalies, the objective of this work is to assess possible climate changes impacts on groundwater levels in this aquifer outcrop zone. Global Climate Models' (GCM) outputs were used as inputs in a transient flux groundwater model created using the software SPA (Simulation of Process in Aquifers), enabling groundwater table fluctuation to be evaluated under distinct climatic scenarios. Six monitoring wells, located in a representative basin (Ribeirão da Onça basin) inside a GAS outcrop zone (ROB), provided water table measurements between 2004 and 2011 to calibrate the groundwater model. Using observed climatic data, a water budget method was applied to estimate recharge in different types of land uses. Statistically downscaled future climate scenarios were used as inputs for that same recharge model, which provided data for running SPA under those scenarios. The results show that most of the GCMs used here predict temperature arises over 275,15 K and major monthly rainfall mean changes to take place in the dry season. During wet seasons, those means might experience around 50% decrease. The transient model results indicate that water table variations, derived from around 70% of the climate scenarios, would vary below those measured between 2004 and 2011. Among the thirteen GCMs considered in this work, only four of them predicted more extreme

  3. A comparison between index of entropy and catastrophe theory methods for mapping groundwater potential in an arid region.

    Science.gov (United States)

    Al-Abadi, Alaa M; Shahid, Shamsuddin

    2015-09-01

    In this study, index of entropy and catastrophe theory methods were used for demarcating groundwater potential in an arid region using weighted linear combination techniques in geographical information system (GIS) environment. A case study from Badra area in the eastern part of central of Iraq was analyzed and discussed. Six factors believed to have influence on groundwater occurrence namely elevation, slope, aquifer transmissivity and storativity, soil, and distance to fault were prepared as raster thematic layers to facility integration into GIS environment. The factors were chosen based on the availability of data and local conditions of the study area. Both techniques were used for computing weights and assigning ranks vital for applying weighted linear combination approach. The results of application of both modes indicated that the most influential groundwater occurrence factors were slope and elevation. The other factors have relatively smaller values of weights implying that these factors have a minor role in groundwater occurrence conditions. The groundwater potential index (GPI) values for both models were classified using natural break classification scheme into five categories: very low, low, moderate, high, and very high. For validation of generated GPI, the relative operating characteristic (ROC) curves were used. According to the obtained area under the curve, the catastrophe model with 78 % prediction accuracy was found to perform better than entropy model with 77 % prediction accuracy. The overall results indicated that both models have good capability for predicting groundwater potential zones.

  4. Regional groundwater modeling of the saturated zone in the vicinity of Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Ahola, M.; Sagar, B.

    1992-10-01

    Results of groundwater modeling of the saturated zone in the vicinity of Yucca Mountain are presented. Both a regional (200 x 200 km) and subregional (50 x 50 km) model were used in the analyses. Simulations were conducted to determine the impact of various disruptive that might take place over the life span of a proposed Yucca Mountain geologic conditions repository on the groundwater flow field, as well as changes in the water-table elevations. These conditions included increases in precipitation and groundwater recharge within the regional model, changes in permeability of existing hydrogeologic barriers, a:nd the vertical intrusion of volcanic dikes at various orientations through the saturated zone. Based on the regional analysis, the rise in the water-table under Yucca Mountain due to various postulated conditions ranged from only a few meters to 275 meters. Results of the subregional model analysis, which was used to simulate intrusive dikes approximately 4 kilometers in length in the vicinity of Yucca Mountain, showed water-table rises ranging from a few meters to as much as 103 meters. Dikes oriented approximately north-south beneath Yucca Mountain produced the highest water-table rises. The conclusions drawn from this analysis are likely to change as more site-specific data become available and as the assumptions in the model are improved

  5. Application of Dempster-Shafer theory of evidence model to geoelectric and hydraulic parameters for groundwater potential zonation

    Directory of Open Access Journals (Sweden)

    Kehinde Anthony Mogaji

    2018-06-01

    Full Text Available The application of a GIS – based Dempster – Shafer data driven model named as evidential belief function EBF- methodology to groundwater potential conditioning factors (GPCFs derived from geophysical and hydrogeological data sets for assessing groundwater potentiality was presented in this study. The proposed method’s efficacy in managing degree of uncertainty in spatial predictive models motivated this research. The method procedural approaches entail firstly, the database containing groundwater data records (bore wells location inventory, hydrogeological data record, etc. and geophysical measurement data construction. From the database, different influencing groundwater occurrence factors, namely aquifer layer thickness, aquifer layer resistivity, overburden material resistivity, overburden material thickness, aquifer hydraulic conductivity and aquifer transmissivity were extracted and prepared. Further, the bore well location inventories were partitioned randomly into a ratio of 70% (19 wells for model training and 30% (9 wells for model testing. The synthesized of the GPCFs via applying the DS – EBF model algorithms produced the groundwater productivity potential index (GPPI map which demarcated the area into low – medium, medium, medium – high and high potential zones. The analyzed percentage degree of uncertainty for the predicted lows potential zones classes and mediums/highs potential zones classes are >10% and <10%, respectively. The DS theory model-based GPPI map’s validation through ROC approach established prediction rate accuracy of 88.8%. Successively, the determined transverse resistance (TR values in the range of 1280 and 30,000 Ω my for the area geoelectrically delineated aquifer units of the predicted potential zones through Dar – Zarrouk Parameter analysis quantitatively confirm the DS theory modeling prediction results. This research results have expand the capability of DS – EBF model in predictive

  6. Vertical Hydraulic Conductivity of Unsaturated Zone by Infiltrometer Analysis of Shallow Groundwater Regime (KUISG

    Directory of Open Access Journals (Sweden)

    Arkan Radhi Ali

    2018-02-01

    Full Text Available A hydrogeologic model was developed and carried out in Taleaa district of 67km2 . The study adopted a determination of KUISG depends upon the double rings infiltrometer model. The tests were carried out in a part of Mesopotamian  Zone which is covered with quaternary deposits  . In general the groundwater levels are about one meter below ground surface.  Theoretically, the inclination angle of the saturated water phase plays an important role in the determination of KUISG. The experimental results prove that the angle of inclination of the saturated phase is identical to the angle of internal friction of the soil. This conclusion is supported by the comparison of the results that obtained from falling head test and infiltrometer measurements for estimating the hydraulic conductivitiy values for ten locations within the study area. The determination of vertical hydraulic conductivity by current infiltrometer model is constrained to only the shallow groundwater regime.7

  7. Assessing the impact of dairy waste lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer.

    Science.gov (United States)

    Baram, S; Kurtzman, D; Ronen, Z; Peeters, A; Dahan, O

    2014-01-01

    Dairy waste lagoons are considered to be point sources of groundwater contamination by chloride (Cl(-)), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl(-) and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy lagoons and the spatial variability in Cl(-) and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy lagoons in this region (0.8%), leachates from lagoons have contributed 6.0% and 12.6% of the total mass of Cl(-) and TN (mainly as NO3(-)-N) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl(-) and TN to the groundwater. A low spatial correlation between the Cl(-) and NO3(-)-N concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl(-) and NO3(-)-N. Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the lagoons would decrease the regional groundwater salinization process (11% of the total Cl(-) load is stored under lagoons). A more considerable reduction in the groundwater contamination by NO3(-)-N is expected (25% of the NO3(-)-N load is stored under lagoons). Results

  8. Scoping Calculations for Potential Groundwater Impacts from Operation of the APT Facility at SRS

    International Nuclear Information System (INIS)

    Thibault, J.J.

    1999-01-01

    The purpose of this study was to determine the potential travel times and paths of the postulated activated groundwater beneath the facility and to examine the fate and transport of this activated groundwater

  9. Neural Network approach to assess the thermal affected zone around the injection well in a groundwater heat pump system

    Science.gov (United States)

    Lo Russo, Stefano; Taddia, Glenda; Verda, Vittorio

    2014-05-01

    The common use of well doublets for groundwater-sourced heating or cooling results in a thermal plume of colder or warmer re-injected groundwater known as the Thermal Affected Zone(TAZ). The plumes may be regarded either as a potential anthropogenic geothermal resource or as pollution, depending on downstream aquifer usage. A fundamental aspect in groundwater heat pump (GWHP) plant design is the correct evaluation of the thermally affected zone that develops around the injection well. Temperature anomalies are detected through numerical methods. Crucial elements in the process of thermal impact assessment are the sizes of installations, their position, the heating/cooling load of the building, and the temperature drop/increase imposed on the re-injected water flow. For multiple-well schemes, heterogeneous aquifers, or variable heating and cooling loads, numerical models that simulate groundwater and heat transport are needed. These tools should consider numerous scenarios obtained considering different heating/cooling loads, positions, and operating modes. Computational fluid dynamic (CFD) models are widely used in this field because they offer the opportunity to calculate the time evolution of the thermal plume produced by a heat pump, depending on the characteristics of the subsurface and the heat pump. Nevertheless, these models require large computational efforts, and therefore their use may be limited to a reasonable number of scenarios. Neural networks could represent an alternative to CFD for assessing the TAZ under different scenarios referring to a specific site. The use of neural networks is proposed to determine the time evolution of the groundwater temperature downstream of an installation as a function of the possible utilization profiles of the heat pump. The main advantage of neural network modeling is the possibility of evaluating a large number of scenarios in a very short time, which is very useful for the preliminary analysis of future multiple

  10. Inverse modeling and uncertainty analysis of potential groundwater recharge to the confined semi-fossil Ohangwena II Aquifer, Namibia

    Science.gov (United States)

    Wallner, Markus; Houben, Georg; Lohe, Christoph; Quinger, Martin; Himmelsbach, Thomas

    2017-12-01

    The identification of potential recharge areas and estimation of recharge rates to the confined semi-fossil Ohangwena II Aquifer (KOH-2) is crucial for its future sustainable use. The KOH-2 is located within the endorheic transboundary Cuvelai-Etosha-Basin (CEB), shared by Angola and Namibia. The main objective was the development of a strategy to tackle the problem of data scarcity, which is a well-known problem in semi-arid regions. In a first step, conceptual geological cross sections were created to illustrate the possible geological setting of the system. Furthermore, groundwater travel times were estimated by simple hydraulic calculations. A two-dimensional numerical groundwater model was set up to analyze flow patterns and potential recharge zones. The model was optimized against local observations of hydraulic heads and groundwater age. The sensitivity of the model against different boundary conditions and internal structures was tested. Parameter uncertainty and recharge rates were estimated. Results indicate that groundwater recharge to the KOH-2 mainly occurs from the Angolan Highlands in the northeastern part of the CEB. The sensitivity of the groundwater model to different internal structures is relatively small in comparison to changing boundary conditions in the form of influent or effluent streams. Uncertainty analysis underlined previous results, indicating groundwater recharge originating from the Angolan Highlands. The estimated recharge rates are less than 1% of mean yearly precipitation, which are reasonable for semi-arid regions.

  11. Flow pathways in the evolving critical zone - insights from hydraulic groundwater theory

    Science.gov (United States)

    Harman, C. J.; Cosans, C.; Kim, M.

    2017-12-01

    The geochemical signatures of the evolving critical zone are delivered into streams via saturated lateral flow through hillslopes. Here we will draw on hydraulic groundwater theory and scaling arguments to obtain insights into the first-order controls on the transition from vertical infiltration to lateral flow in the critical zone. Hydraulic groundwater theory aims to provide a simplified description of unconfined, saturated groundwater flow in systems that are substantially larger in lateral than vertical extent. The theory rests on the Dupuit assumptions, which are often erroneously stated as including an assumption of exclusively lateral flow. In fact the full three-dimensional flow field can be approximated from these assumptions. Building on this theory, we examine how overall hillslope structure (slope, permeability, convergence/divergence etc.) determines the direction and magnitude of flow in the vicinity of weathering fronts in the critical zone, and how weathering products are delivered to the hillslope base. The results demonstrate that under certain conditions the mere presence of lateral flow will not disturb the lateral symmetry of reaction fronts along the hillslope. Furthermore, coupling to a simple reaction model with porosity/permeability feedback allows us to examine the implications for weathering front advance where saturated lateral flow occurs as a transient perched aquifer at the weathering front. The overall rate of weathering front advance is found to be primarily determined by the component of flow normal to the weathering front, and only significantly accelerated by the lateral component above the weathering front when parent rock permeability is very low.

  12. Estimating the dynamics of groundwater input into the coastal zone via continuous radon-222 measurements

    International Nuclear Information System (INIS)

    Burnett, William C.; Dulaiova, Henrieta

    2003-01-01

    Submarine groundwater discharge (SGD) into the coastal zone has received increased attention in the last few years as it is now recognized that this process represents an important pathway for material transport. Assessing these material fluxes is difficult, as there is no simple means to gauge the water flux. To meet this challenge, we have explored the use of a continuous radon monitor to measure radon concentrations in coastal zone waters over time periods from hours to days. Changes in the radon inventories over time can be converted to fluxes after one makes allowances for tidal effects, losses to the atmosphere, and mixing with offshore waters. If one assumes that advective flow of radon-enriched groundwater (pore waters) represent the main input of 222 Rn in the coastal zone, the calculated radon fluxes may be converted to water fluxes by dividing by the estimated or measured 222 Rn pore water activity. We have also used short-lived radium isotopes ( 223 Ra and 224 Ra) to assess mixing between near-shore and offshore waters in the manner pioneered by . During an experiment in the coastal Gulf of Mexico, we showed that the mixing loss derived from the 223 Ra gradient agreed very favorably to the estimated range based on the calculated radon fluxes. This allowed an independent constraint on the mixing loss of radon--an important parameter in the mass balance approach. Groundwater discharge was also estimated independently by the radium isotopic approach and was within a factor of two of that determined by the continuous radon measurements and an automated seepage meter deployed at the same site

  13. A comparative assessment of GIS-based data mining models and a novel ensemble model in groundwater well potential mapping

    Science.gov (United States)

    Naghibi, Seyed Amir; Moghaddam, Davood Davoodi; Kalantar, Bahareh; Pradhan, Biswajeet; Kisi, Ozgur

    2017-05-01

    by determining high and very high groundwater potential zones.

  14. Isotope hydrology of groundwaters in the Donana National Park and the associated zone of influence

    International Nuclear Information System (INIS)

    Plata, A.; Baonza, E.; Silgado, A.

    1984-01-01

    The authors describe a study, using environmental isotopes, of the groundwaters of a complex hydrological system formed by a free recharge zone with a multi-layer structure, a confined zone with connate waters trapped by the deposition of a thick clay layer in a coastal pool environment, and a series of both recent and ancient highly permeable dune formations. Attempts have been made, using tritium of thermonuclear origin, to determine the approximate average recharge rate during the last 28 years in the free aquifer zone. Despite the difficulties encountered, the value of 78 mm/a obtained, which is 13.2% of the average precipitation, is very similar to that obtained using conventional methods (approximately 84 mm/a). As was expected, there was no tritium in the confined zone. Carbon-14 was used to determine the reduced velocity of the underground stream and to confirm the network of streams deduced from conductivity measurements. The age-correction methods proposed by Tamers, Pearson, Mook and Fontes were compared. The differences in age between the last method and the first two are reasonable and can be explained by the isotopic interchange between the CaCO 3 of the rock formation and the gaseous CO 2 included in Fontes' model. On the other hand, the differences found with the Mook method are considerable, particularly for sample values below delta 13 C. The last model is more sensitive to changes in delta 13 C, and the interval of this parameter for which this model gives reasonable values of age is very small. In addition, the 14 C made it possible to determine the sedimentation velocity of clays in the swamp zone. The stable isotopes in the water confirmed the hypothesis that the underground waters in the confinement zone are a mixture of fresh water which has infiltrated into the recharge zone and of connate water trapped by the deposition of the clay layer. (author)

  15. Groundwater flow, nutrient, and stable isotope dynamics in the parafluvial-hyporheic zone of the regulated Lower Colorado River (Texas, USA) over the course of a small flood

    Science.gov (United States)

    Briody, Alyse C.; Cardenas, M. Bayani; Shuai, Pin; Knappett, Peter S. K.; Bennett, Philip C.

    2016-06-01

    Periodic releases from an upstream dam cause rapid stage fluctuations in the Lower Colorado River near Austin, Texas, USA. These daily pulses modulate fluid exchange and residence times in the hyporheic zone where biogeochemical reactions are typically pronounced. The effects of a small flood pulse under low-flow conditions on surface-water/groundwater exchange and biogeochemical processes were studied by monitoring and sampling from two dense transects of wells perpendicular to the river. The first transect recorded water levels and the second transect was used for water sample collection at three depths. Samples were collected from 12 wells every 2 h over a 24-h period which had a 16-cm flood pulse. Analyses included nutrients, carbon, major ions, and stable isotopes of water. The relatively small flood pulse did not cause significant mixing in the parafluvial zone. Under these conditions, the river and groundwater were decoupled, showed potentially minimal mixing at the interface, and did not exhibit any discernible denitrification of river-borne nitrate. The chemical patterns observed in the parafluvial zone can be explained by evaporation of groundwater with little mixing with river water. Thus, large pulses may be necessary in order for substantial hyporheic mixing and exchange to occur. The large regulated river under a low-flow and small flood pulse regime functioned mainly as a gaining river with little hydrologic connectivity beyond a narrow hyporheic zone.

  16. Mapping of groundwater spring potential zone using geospatial ...

    Indian Academy of Sciences (India)

    9

    geographical information system and remote sensing with various ... integration of RS and GIS and multi-criteria decision-making techniques, .... terrain factor contains the S (spring) before taking a class of terrain factor (F) into account and its.

  17. Using Groundwater physiochemical properties for assessing potential earthquake precursor

    Science.gov (United States)

    Inbar, Nimrod; Reuveni, Yuval; Anker, Yaakov; Guttman, Joseph

    2017-04-01

    Worldwide studies reports pre-seismic, co-seismic and post-seismic reaction of groundwater to earthquakes. The unique hydrological and geological situation in Israel resulted in relatively deep water wells which are located close to seismically active tectonic plate boundary. Moreover, the Israeli experience show that anomalies may occurs 60-90 minutes prior to the seismic event (Guttman et al., 2005; Anker et al., 2016). Here, we try to assess the possible connection between changes in physiochemical parameters of groundwater and earthquakes along the Dead Sea Transform (DST) region. A designated network of monitoring stations was installed in MEKOROT abandoned deep water wells, continuously measuring water table, conductivity and temperature at a sampling rate of 1 minute. Preliminary analysis compares changes in the measured parameters with rain events, tidal effects and earthquake occurrences of all measured magnitudes (>2.5Md) at monitoring area surroundings. The acquired data set over one year recorded simultaneous abrupt changes in several wells which seems disconnected from standard hydrological occurrences such as precipitation, abstraction or tidal effects. At this stage, our research aims to determine and rationalize a baseline for "normal response" of the measured parameters to external occurrences while isolating those cases in which "deviations" from that base line is recorded. We apply several analysis techniques both in time and frequency domain with the measured signal as well as statistical analysis of several measured earthquake parameters, which indicate potential correlations between earthquakes occurrences and the measured signal. We show that at least in one seismic event (5.1 Md) a potential precursor may have been recorded. Reference: Anker, Y., N. Inbar, A. Y. Dror, Y. Reuveni, J. Guttman, A. Flexer, (2016). Groundwater response to ground movements, as a tool for earthquakes monitoring and a possible precursor. 8th International Conference

  18. Pollution Status of Trace Metals in Groundwater Due to Industrail Activities in and Around Dhaka Export Processing Zone, Bangladesh

    Directory of Open Access Journals (Sweden)

    GOLAM AHMED

    2012-06-01

    Full Text Available Effluents from multiindustrail activities influence inland water system directly, which subsiquently affect groundwater quality and human health. Some previous reports indicated that inadequate treatment process of discharged effluent of Dhaka Export Processing Zone (DEPZ increased the concentrations of pollutants in surface water system and deteriorated total fishing and agricultural system around DEPZ and its connected area. Therefore, the present study was conducted to investigate wether the concentration of selective metals viz. Li, V, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and U in two types of groundwater sources were either with in the permissible guidlines or influenced by DEPZ multi industrail on their levels of contamination. The concentrations of metals were determined using inductively Couples Plasma Mass Spectrometry (ICP-MS. The mean concentrations of the elements in both types of groundwater were in the levels of their permissible guidlines, except for Ni (12.91 µg/L, Ga (0.48µg/L, Sr (90.26 µg/L and Cs (0.07µg//Lin groundwater inside DEPZ, which were 1.30, 5.00, 1.50 and 1.40 times higher than the maximum permissible limit (MPL of 10 µg/L, 0.09 µg/L, 60 µg/L, and 0.05µg/L, respectively. The mean concentrations of Li (6.85 µg/L, Zn(268 µg/L, Ga (0.12 µg/L, Sr (131 µg/L and Cs (0.07 µg/L were 3.43, 1.34, 1.33, 2.18, 1.40 times higher then the MPL of 2 µg/L, 200 µg/L, 0.09 µg/L, 60 µg/L and 0.05 µg/L, respectively, in groundwater around DEPZ. Comparatively Zn and Sr possessed higher concentrations, and Cs and U possessed lower concentration in both types of groundwater sources. The elements were distributed in homogeneous and hetrogeneous manner among the source points for deep-tubewell (DTWS and shallow tubewell (STWs, respectively. The significant positive correlations were found between the elements viz., Co-V (0.85, Ni-Sr ((0.70, Co-Cd (0.86, As-Se (0.99, Cs-Zn (0.95, Li-U (0.,71, Zn-U (0

  19. Utilizing potential field data to support delineation of groundwater aquifers in the southern Red Sea coast, Saudi Arabia

    International Nuclear Information System (INIS)

    Elawadi, Eslam; Mogren, Saad; Ibrahim, Elkhedr; Batayneh, Awni; Al-Bassam, Abdulaziz

    2012-01-01

    In this paper potential field data are interpreted to map the undulation of the basement surface, which represents the bottom of the water bearing zones, and to delineate the tectonic framework that controls the groundwater flow and accumulation in the southern Red Sea coastal area of Saudi Arabia. The interpretation reveals that the dominant structural trend is a NW (Red Sea) trend that resulted in a series of faulted tilted blocks. These tilted blocks are dissected by another cross-cut NE trend which shapes and forms a series of fault-bounded small basins. These basins and the bounded structural trends control and shape the flow direction of the groundwater in the study area, i.e. they act as groundwater conduits. Furthermore, the present results indicate that volcanic intrusions are present as subsurface flows, which hinder the groundwater exploration and drilling activities in most of the area; in some localities these volcanic flows crop out at the surface and cover the groundwater bearing formations. Furthermore, the gravity and magnetic data interpretation indicates the possible existence of a large structural basin occupying the southeastern side of the study area. This basin is bounded with NW and NE trending faults and is expected to be a good host for groundwater aquifers; thus it is a promising site for hydrogeological investigation. (paper)

  20. A GIS-based model of potential groundwater yield zonation for a sandstone aquifer in the Juye Coalfield, Shangdong, China

    Science.gov (United States)

    Yin, Huiyong; Shi, Yongli; Niu, Huigong; Xie, Daolei; Wei, Jiuchuan; Lefticariu, Liliana; Xu, Shuanxiang

    2018-02-01

    Resolving the potential groundwater yield zonation of sandstone aquifers occurring at depths of several hundred meters has been an important and challenging objective of the hydrogeological research focused on preventing flood hazards in coal mines. Using accessible geological exploration data we put forward a method of predicting the spatial distribution of groundwater storage potential in sandstone aquifers from Permian-age coal deposits in Juye Coalfield, Shangdong, China. A Geological, Tectonic and Lithological Composition Index (GTLCI) model was created using the following parameters: sandstone depth and thickness, faults length density (FaLD), faults density (FaD), fault frequency density (FaFD), fault scale density (FaSD), variation coefficient of the slope (VCS) of the coal seam, intensity index of folds in horizontal direction (IIFoH), and lithological composition index (LCI). Each of these factors was subsequently divided into 5 classes. The analytic hierarchy process (AHP) and trapezoidal fuzzy number (TFN) method was applied to calculate the weight of the conditioning factor and their respective sub-classes. Groundwater yield potential contour map, which was initially constructed using the GTLCI values revealed four groundwater abundance zones. The map was further refined by taking into account hydrogeologic data collected during mining activities. The GTLCI model predictive success rate of 80% was explained by the limited number of boreholes available for validation. It is considered that the GTLCI model is effective at predicting zonation of groundwater yield in the sandstone aquifers from Permian- age coal deposits in Juye Coalfield, China.

  1. Arsenic transport in groundwater, surface water, and the hyporheic zone of a mine-influenced stream-aquifer system

    OpenAIRE

    Brown, Brendan

    2005-01-01

    We investigated the transport of dissolved arsenic in groundwater, surface water and the hyporheic zone in a stream-aquifer system influenced by an abandoned arsenopyrite mine. Mine tailing piles consisting of a host of arsenic-bearing minerals including arsenopyrite and scorodite remain adjacent to the stream and represent a continuous source of arsenic. Arsenic loads from the stream, springs, and groundwater were quantified at the study reach on nine dates from January to August 2005 and ...

  2. Natural attenuation potential of phenylarsenicals in anoxic groundwaters.

    Science.gov (United States)

    Hempel, Michael; Daus, Birgit; Vogt, Carsten; Weiss, Holger

    2009-09-15

    The extensive production of chemical warfare agents in the 20th century has led to serious contamination of soil and groundwater with phenyl arsenicals at former ammunition depots or warfare agent production sites worldwide. Most phenyl arsenicals are highly toxic for humans. The microbial degradation of phenylarsonic acid (PAA) and diphenylarsinic acid (DPAA) was investigated in microcosms made of anoxic groundwater/sediment mixtures taken from different depths of an anoxic, phenyl arsenical contaminated aquifer in Central Germany. DPAA was not transformed within 91 days incubation time in any of the microcosms. The removal of PAA can be described by a first order kinetics without a lag-phase (rate: 0.037 d(-1)). In sterilized microcosms, PAA concentrations always remained stable, demonstrating that PAA transformation was a biologically mediated process. PAA transformation occurred under sulfate-reducing conditions due to sulfate consumption and production of sulfide. The addition of lactate (1 mM), a typical substrate of sulfate-reducing bacteria, increased the transformation rate of PAA significantly up to 0.134 d(-1). The content of total arsenic was considerably reduced (> 75%). Intermediates of PAA transformation were detected by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Experiments with a pure strain and sterile controls of Desulfovibrio gigas spiked with PAA showed that the elimination process is linked to the presence of sulfide formed through bacterial activity. Phenyl arsenicals were likely immobilized in the sedimentthrough sulfur substitution and a subsequent sulfur bond under the prevailing sulfate reducing condition. The results of this study indicate that PAA can undergo microbiologically mediated transformation in anoxic aquifers, leading to reduced concentrations in groundwater, which indicate a (enhancend) natural attenuation potential.

  3. Linking chloride mass balance infiltration rates with chlorofluorocarbon and SF6 groundwater dating in semi-arid settings: potential and limitations.

    Science.gov (United States)

    Stadler, Susanne; Osenbruck, Karsten; Duijnisveld, Wilhelmus H M; Schwiede, Martin; Bottcher, Jurgen

    2010-09-01

    In the framework of the investigation of enrichment processes of nitrate in groundwater of the Kalahari of Botswana near Serowe, recharge processes were investigated. The thick unsaturated zone extending to up to 100 m of mostly unconsolidated sediments and very low recharge rates pose a serious challenge to study solute transport related to infiltration and recharge processes, as this extends past the conventional depths of soil scientific investigations and is difficult to describe using evidence from the groundwater due to the limitations imposed by available tracers. To determine the link between nitrate in the vadose zone and in the uppermost groundwater, sediment from the vadose zone was sampled up to a depth of 15-20 m (in one case also to 65 m) on several sites with natural vegetation in the research area. Among other parameters, sediment and water were analysed to determine chloride and nitrate concentration depth profiles. Using the chloride mass balance method, an estimation of groundwater infiltration rates produced values of 0.2-4 mm a(-1). The uncertainty of these values is, however, high. Because of the extreme thickness of the vadose zone, the travel time in the unsaturated zone might reach extreme values of up to 500 years and more. For investigations using groundwater, we applied the chlorofluorocarbons CFC-113, CFC-12, sulphur hexafluoride (SF(6)) and tritium to identify potential recharge, and found indications for some advective transport of the CFCs and SF(6), which we accounted for as constituting potential active localised recharge. In our contribution, we show the potential and limitations of the applied methods to determine groundwater recharge and coupled solute transport in semi-arid settings, and compare travel time ranges derived from soil science and groundwater investigations.

  4. The vadose zone as a geoindicator of environmental change and groundwater quality in water-scarce areas

    Science.gov (United States)

    Edmunds, W. M.; Baba Goni, I.; Gaye, C. B.; Jin, L.

    2013-12-01

    Inert and reactive tracers in moisture profiles provide considerable potential for the vadose zone to be used as an indicator of rapid environmental change. This indicator is particularly applicable in areas of water stress where long term (decade to century) scale records may be found in deep unsaturated zones in low rainfall areas and provide insights into recent recharge, climate variation and water-rock interactions which generate groundwater quality. Unsaturated zone Cl records obtained by elutriation of moisture are used widely for estimating recharge and water balance studies; isotope profiles (3H, δ2H, δ18O) from total water extraction procedures are used for investigation of residence times and hydrological processes. Apart from water taken using lysimeters, little work has been conducted directly on the geochemistry of pore fluids. This is mainly due to the difficulties of extraction of moisture from unsaturated material with low water contents (typically 2-6 wt%) and since dilution methods can create artifacts. Using immiscible liquid displacement techniques it is now possible to directly investigate the geochemistry of moisture from unsaturated zone materials. Profiles up to 35m from Quaternary sediments from dryland areas of the African Sahel (Nigeria, Senegal) as well as Inner Mongolia, China are used to illustrate the breadth of information obtainable from vadose zone profiles. Using pH, major and trace elements and comparing with isotopic data, a better understanding is gained of timescales of water movement, aquifer recharge, environmental records and climate history as well as water-rock interaction and contaminant behaviour. The usefulness of tritium as residence time indicator has now expired following cessation of atmospheric thermonuclear testing and through radioactive decay. Providing the rainfall Cl, moisture contents and bulk densities of the sediments are known, then Cl accumulation can be substituted to estimate timescales. Profiles

  5. Metamodeling and mapping of nitrate flux in the unsaturated zone and groundwater, Wisconsin, USA

    Science.gov (United States)

    Nolan, Bernard T.; Green, Christopher T.; Juckem, Paul F.; Liao, Lixia; Reddy, James E.

    2018-01-01

    Nitrate contamination of groundwater in agricultural areas poses a major challenge to the sustainability of water resources. Aquifer vulnerability models are useful tools that can help resource managers identify areas of concern, but quantifying nitrogen (N) inputs in such models is challenging, especially at large spatial scales. We sought to improve regional nitrate (NO3−) input functions by characterizing unsaturated zone NO3− transport to groundwater through use of surrogate, machine-learning metamodels of a process-based N flux model. The metamodels used boosted regression trees (BRTs) to relate mappable landscape variables to parameters and outputs of a previous “vertical flux method” (VFM) applied at sampled wells in the Fox, Wolf, and Peshtigo (FWP) river basins in northeastern Wisconsin. In this context, the metamodels upscaled the VFM results throughout the region, and the VFM parameters and outputs are the metamodel response variables. The study area encompassed the domain of a detailed numerical model that provided additional predictor variables, including groundwater recharge, to the metamodels. We used a statistical learning framework to test a range of model complexities to identify suitable hyperparameters of the six BRT metamodels corresponding to each response variable of interest: NO3− source concentration factor (which determines the local NO3− input concentration); unsaturated zone travel time; NO3− concentration at the water table in 1980, 2000, and 2020 (three separate metamodels); and NO3− “extinction depth”, the eventual steady state depth of the NO3−front. The final metamodels were trained to 129 wells within the active numerical flow model area, and considered 58 mappable predictor variables compiled in a geographic information system (GIS). These metamodels had training and cross-validation testing R2 values of 0.52 – 0.86 and 0.22 – 0.38, respectively, and predictions were compiled as maps of the above

  6. Metamodeling and mapping of nitrate flux in the unsaturated zone and groundwater, Wisconsin, USA

    Science.gov (United States)

    Nolan, Bernard T.; Green, Christopher T.; Juckem, Paul F.; Liao, Lixia; Reddy, James E.

    2018-04-01

    Nitrate contamination of groundwater in agricultural areas poses a major challenge to the sustainability of water resources. Aquifer vulnerability models are useful tools that can help resource managers identify areas of concern, but quantifying nitrogen (N) inputs in such models is challenging, especially at large spatial scales. We sought to improve regional nitrate (NO3-) input functions by characterizing unsaturated zone NO3- transport to groundwater through use of surrogate, machine-learning metamodels of a process-based N flux model. The metamodels used boosted regression trees (BRTs) to relate mappable landscape variables to parameters and outputs of a previous "vertical flux method" (VFM) applied at sampled wells in the Fox, Wolf, and Peshtigo (FWP) river basins in northeastern Wisconsin. In this context, the metamodels upscaled the VFM results throughout the region, and the VFM parameters and outputs are the metamodel response variables. The study area encompassed the domain of a detailed numerical model that provided additional predictor variables, including groundwater recharge, to the metamodels. We used a statistical learning framework to test a range of model complexities to identify suitable hyperparameters of the six BRT metamodels corresponding to each response variable of interest: NO3- source concentration factor (which determines the local NO3- input concentration); unsaturated zone travel time; NO3- concentration at the water table in 1980, 2000, and 2020 (three separate metamodels); and NO3- "extinction depth", the eventual steady state depth of the NO3- front. The final metamodels were trained to 129 wells within the active numerical flow model area, and considered 58 mappable predictor variables compiled in a geographic information system (GIS). These metamodels had training and cross-validation testing R2 values of 0.52 - 0.86 and 0.22 - 0.38, respectively, and predictions were compiled as maps of the above response variables. Testing

  7. Determining flow, recharge, and vadose zone drainage in an unconfined aquifer from groundwater strontium isotope measurements, Pasco Basin, WA

    International Nuclear Information System (INIS)

    2004-01-01

    Strontium isotope compositions (87Sr/86Sr) measured in groundwater samples from 273 wells in the Pasco Basin unconfined aquifer below the Hanford Site show large and systematic variations that provide constraints on groundwater recharge, weathering rates of the aquifer host rocks, communication between unconfined and deeper confined aquifers, and vadose zone-groundwater interaction. The impact of millions of cubic meters of wastewater discharged to the vadose zone (103-105 times higher than ambient drainage) shows up strikingly on maps of groundwater 87Sr/86Sr. Extensive access through the many groundwater monitoring wells at the site allows for an unprecedented opportunity to evaluate the strontium geochemistry of a major aquifer, hosted primarily in unconsolidated sediments, and relate it to both long term properties and recent disturbances. Groundwater 87Sr/86Sr increases systematically from 0.707 to 0.712 from west to east across the Hanford Site, in the general direction of groundwater flow, as a result of addition of Sr from the weathering of aquifer sediments and from diffuse drainage through the vadose zone. The lower 87Sr/86Sr groundwater reflects recharge waters that have acquired Sr from Columbia River Basalts. Based on a steady-state model of Sr reactive transport and drainage, there is an average natural drainage flux of 0-1.4 mm/yr near the western margin of the Hanford Site, and ambient drainage may be up to 30 mm/yr in the center of the site assuming an average bulk rock weathering rate of 10-7.5 g/g/yr

  8. Groundwater management in coastal zones and on islands in crystalline bedrock areas of Sweden

    Science.gov (United States)

    Banzhaf, Stefan; Ekström, Linda Louise; Ljungkvist, Andreas; Granberg, Maria; Merisalu, Johanna; Pokorny, Sebastian; Barthel, Roland

    2017-04-01

    Groundwater problems in coastal regions are usually not associated with the sparsely populated shores of water-rich Scandinavia. However, the combination of geology and the specific conditions of water usage create challenges even there. Along the Swedish coast, much of the groundwater occurs in fractured bedrock or in relatively small, shallow, and isolated quaternary sedimentary formations. Those aquifers cannot provide water to larger permanent settlements and are thus neither useful for the public water supply nor have previously received much attention from water authorities or researchers. However, of the 450,000 private wells in Sweden, many are located in coastal areas or on islands, creating pressure on groundwater resources in summer months as periods with low or no natural groundwater recharge. In view of the increasing water demand, as well as the awareness of environmental impacts and climate change, Swedish municipalities now recognize groundwater usage in coastal areas is a major concern. Here, we present the results of an investigation on the "Koster" archipelago which forms a microcosm of coastal zone groundwater problems in Sweden. Koster's geology is dominated by fractured, crystalline bedrock with occasional shallow quaternary deposits in between. With around 300 permanent residents, and up to 6,000 summer guests in peak holiday season, the existing water supply based on 800 private wells is at its limit. Water availability forms an obstacle to future development and the current mode of operation is unsustainable. Therefore, the municipality must decide how to secure future water supply which involves complex legal problems, as well as social, cultural, economic, hydrogeological, and environmental questions. As there are no observation wells on the islands, we used approximately 220 of the 800 wells (65% dug and shallow, 35% drilled and up to 120m deep) for our monitoring. Additionally, water samples were collected by property owners on four

  9. Acid-base status of soils in groundwater discharge zones — relation to surface water acidification

    Science.gov (United States)

    Norrström, Ann Catrine

    1995-08-01

    Critical load calculations have suggested that groundwater at depth of 2 m in Sweden is very sensitive to acid load. As environmental isotope studies have shown that most of the runoff in streams has passed through the soil, there is a risk in the near future of accelerated acidification of surface waters. To assess the importance of the last soil horizon of contact before discharge, the upper 0-0.2m of soils in seven discharge zones were analysed for pools of base cations, acidity and base saturation. The sites were about 3-4 m 2 in size and selected from two catchments exposed to different levels of acid deposition. The soils in the seven sites had high concentrations of exchangeable base cations and consequently high base saturation. The high correlation ( r2 = 0.74) between base saturation in the soils of the discharge zones and mean pH of the runoff waters suggested that the discharge zone is important for surface water acidification. The high pool of exchangeable base cations will buffer initially against the acid load. As the cation exchange capacity (meq dm -3) and base saturation were lower in the sites from the catchment receiving lower deposition, these streams may be more vulnerable to acidification in the near future. The high concentration of base cations in non-exchangeable fractions may also buffer against acidification as it is likely that some of these pools will become exchangeable with time.

  10. Generation of 3-D hydrostratigraphic zones from dense airborne electromagnetic data to assess groundwater model prediction error

    Science.gov (United States)

    Christensen, N. K.; Minsley, B. J.; Christensen, S.

    2017-02-01

    We present a new methodology to combine spatially dense high-resolution airborne electromagnetic (AEM) data and sparse borehole information to construct multiple plausible geological structures using a stochastic approach. The method developed allows for quantification of the performance of groundwater models built from different geological realizations of structure. Multiple structural realizations are generated using geostatistical Monte Carlo simulations that treat sparse borehole lithological observations as hard data and dense geophysically derived structural probabilities as soft data. Each structural model is used to define 3-D hydrostratigraphical zones of a groundwater model, and the hydraulic parameter values of the zones are estimated by using nonlinear regression to fit hydrological data (hydraulic head and river discharge measurements). Use of the methodology is demonstrated for a synthetic domain having structures of categorical deposits consisting of sand, silt, or clay. It is shown that using dense AEM data with the methodology can significantly improve the estimated accuracy of the sediment distribution as compared to when borehole data are used alone. It is also shown that this use of AEM data can improve the predictive capability of a calibrated groundwater model that uses the geological structures as zones. However, such structural models will always contain errors because even with dense AEM data it is not possible to perfectly resolve the structures of a groundwater system. It is shown that when using such erroneous structures in a groundwater model, they can lead to biased parameter estimates and biased model predictions, therefore impairing the model's predictive capability.

  11. Generation of 3-D hydrostratigraphic zones from dense airborne electromagnetic data to assess groundwater model prediction error

    Science.gov (United States)

    Christensen, Nikolaj K; Minsley, Burke J.; Christensen, Steen

    2017-01-01

    We present a new methodology to combine spatially dense high-resolution airborne electromagnetic (AEM) data and sparse borehole information to construct multiple plausible geological structures using a stochastic approach. The method developed allows for quantification of the performance of groundwater models built from different geological realizations of structure. Multiple structural realizations are generated using geostatistical Monte Carlo simulations that treat sparse borehole lithological observations as hard data and dense geophysically derived structural probabilities as soft data. Each structural model is used to define 3-D hydrostratigraphical zones of a groundwater model, and the hydraulic parameter values of the zones are estimated by using nonlinear regression to fit hydrological data (hydraulic head and river discharge measurements). Use of the methodology is demonstrated for a synthetic domain having structures of categorical deposits consisting of sand, silt, or clay. It is shown that using dense AEM data with the methodology can significantly improve the estimated accuracy of the sediment distribution as compared to when borehole data are used alone. It is also shown that this use of AEM data can improve the predictive capability of a calibrated groundwater model that uses the geological structures as zones. However, such structural models will always contain errors because even with dense AEM data it is not possible to perfectly resolve the structures of a groundwater system. It is shown that when using such erroneous structures in a groundwater model, they can lead to biased parameter estimates and biased model predictions, therefore impairing the model's predictive capability.

  12. The interaction between the unsaturated zone, aquifer, and stream during a period of groundwater withdrawal

    DEFF Research Database (Denmark)

    Poulsen, Søren Erbs; Christensen, Steen; Rasmussen, Keld Rømer

    2011-01-01

    drainage responses to water-table drawdown. The responses can be sufficiently modeled by estimating the specific yield and five exponential time constants of a Moench/Boulton type model of delayed drainage. The average specific yield is thus estimated to 0.24 which is in agreement with previous small scale......; in the second case the estimate (0.17) is in better agreement with core and previous estimates (0.24). The analysis indicates that relatively fast drainage, and the existence of two drawdown dependent sources of groundwater recharge (the storage and the stream), complicates pumping test design to obtain unique...... parameter estimation. The analysis supports that an essential factor in parameter estimation by pumping test analysis for (at least some) unconfined aquifers is the use of a model that accounts for time-varying drainage from the vadose zone. Finally, when predicting stream depletion beyond 1. day of pumping...

  13. Role of groundwater oxidation potential and radiolysis on waste glass performance in crystalline repository environments

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Bibler, N.E.

    1985-01-01

    Laboratory experiments have shown that groundwater conditions in a Stripa granite repository will be as reducing as those in a basalt repository. The final oxidation potential (Eh) at 70 0 C for Stripa groundwater deaerated and equilibrated with crystalline granite was -0.45V. In contrast, the oxidation potential at 60 0 C for Grande Ronde groundwater equilibrated with basalt was -0.40V. The reducing groundwater conditions were found to slightly decrease the time-dependent release of soluble components from the waste glass. Spectrophotometric analysis of the equilibrated groundwaters indicated the presence of Fe 2+ confirming that the Fe 2+ /Fe 3+ couple is controlling the oxidation potential. It was also shown that in the alkaline pH regime of these groundwaters the iron species are primarily associated with x-ray amorphous precipitates in the groundwater. Gamma radiolysis in the absence of waste glass and in the absence of oxygen further reduces the oxidation potential of both granitic and basaltic groundwaters. The effect is more pronounced in the basaltic groundwater. The mechanism for this decrease is under investigation but appears related to the reactive amorphous precipitate. The results of these tests suggest that H 2 may not escape from the repository system as postulated and that radiolysis may not cause the groundwaters to become oxidizing in a crystalline repository when abundant Fe 2+ species are present. 23 refs., 3 figs., 3 tabs

  14. An isotopic view of water and nitrate transport through the vadose zone in Oregon's southern Willamette Valley's Groundwater Management Area

    Science.gov (United States)

    Brooks, J. R.; Pearlstein, S.; Hutchins, S.; Faulkner, B. R.; Rugh, W.; Willard, K.; Coulombe, R.; Compton, J.

    2017-12-01

    Groundwater nitrate contamination affects thousands of households in Oregon's southern Willamette Valley and many more across the USA. The southern Willamette Valley Groundwater Management Area (GWMA) was established in 2004 due to nitrate levels in the groundwater exceeding the human health standard of 10 mg nitrate-N L-1. Much of the nitrogen (N) inputs to the GWMA comes from agricultural fertilizers, and thus efforts to reduce N inputs to groundwater are focused upon improving N management. However, the effectiveness of these improvements on groundwater quality is unclear because of the complexity of nutrient transport through the vadose zone and long groundwater residence times. Our objective was to focus on vadose zone transport and understand the dynamics and timing of N and water movement below the rooting zone in relation to N management and water inputs. Stable isotopes are a powerful tool for tracking water movement, and understanding N transformations. In partnership with local farmers and state agencies, we established lysimeters and groundwater wells in multiple agricultural fields in the GWMA, and have monitored nitrate, nitrate isotopes, and water isotopes weekly for multiple years. Our results indicate that vadose zone transport is highly complex, and the residence time of water collected in lysimeters was much longer than expected. While input precipitation water isotopes were highly variable over time, lysimeter water isotopes were surprisingly consistent, more closely resembling long-term precipitation isotope means rather than recent precipitation isotopic signatures. However, some particularly large precipitation events with unique isotopic signatures revealed high spatial variability in transport, with some lysimeters showing greater proportions of recent precipitation inputs than others. In one installation where we have groundwater wells and lysimeters at multiple depths, nitrate/nitrite concentrations decreased with depth. N concentrations

  15. Evaluating the Potential of Groundwater Pollution in Kherran and Zoweircherry Plains through GIS-based DRASTIC Model

    Directory of Open Access Journals (Sweden)

    Manouchehr Chitsazan

    2006-09-01

    Full Text Available Zoweircherry and Kherran plains are located in the northeast ofAhwazin Khuzestan province. The water supply of these plains is a crucial issue and the quality of groundwater is also under the threat as a result of an increase in the use of agrochemicals. For this reason, assessing the vulnerability is an important factor in any policy-making decision for these plains. Focusing on this issue, this paper attempts to produce a groundwater vulnerability map for Zoweircherry and Kherran plains. The map is designed to show areas of highest potential for groundwater pollution on the basis of hydro-geological conditions and human impacts. Seven major hydro-geological factors (depth to water table, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity were incorporated into DRASTIC model and Geographical Information System (GIS was used to create a groundwater vulnerability map by overlaying the available hydro-geological data. The results of model exhibit that the west and southwest of the aquifer are dominated by medium vulnerability while small areas on northwest and east of the study area have no risk of pollution. Other parts of aquifer have low vulnerability. The nitrate analysis of groundwater samples shows that the existing nitrate on the west and southwest parts of aquifer is more than the existing nitrate on its other parts which, therefore, confirms the results of the vulnerability assessment.

  16. Identification of potential groundwater flow paths using geological and geophysical data

    International Nuclear Information System (INIS)

    Pohlmann, K.; Andricevic, R.

    1994-09-01

    This project represents the first phase in the development of a methodology for generating three-dimensional equiprobable maps of hydraulic conductivity for the Nevada Test Site (NTS). In this study, potential groundwater flow paths were investigated for subsurface tuffs at Yucca Flat by studying how these units are connected. The virtual absence of site-specific hydraulic conductivity data dictates that as a first step a surrogate attribute (geophysical logs) be utilized. In this first phase, the connectivity patterns of densely welded ash-flow tuffs were studied because these tuffs are the most likely to form zones of high hydraulic conductivity. Densely welded tuffs were identified based on the response shown on resistivity logs and this information was transformed into binary indicator values. The spatial correlation of the indicator data was estimated through geostatistical methods. Equiprobable three-dimensional maps of the distribution of the densely-welded and nonwelded tuffs (i.e., subsurface heterogeneity) were then produced using a multiple indicator simulation formalism. The simulations demonstrate that resistivity logs are effective as soft data for indicating densely welded tuffs. The simulated welded tuffs reproduce the stratigraphic relationships of the welded tuffs observed in hydrogeologic cross sections, while incorporating the heterogeneity and anisotropy that is expected in this subsurface setting. Three-dimensional connectivity of the densely welded tuffs suggests potential groundwater flow paths with lengths easily over 1 km. The next phase of this investigation should incorporate other geophysical logs (e.g., gamma-gamma logs) and then calibrate the resulting soft data maps with available hard hydraulic conductivity data. The soft data maps can then augment the hard data to produce the final maps of the spatial distribution of hydraulic conductivity that can be used as input for numerical solution of groundwater flow and transport

  17. Seasonal variations in groundwater upwelling zones in a Danish lowland stream analyzed using Distributed Temperature Sensing (DTS)

    DEFF Research Database (Denmark)

    Matheswaran, Karthikeyan; Blemmer, Morten; Rosbjerg, Dan

    2014-01-01

    –night temperature difference were applied to three DTS datasets representing stream temperature responses to the variable meteorological and hydrological conditions prevailing in summer, winter and spring. The standard deviation criterion was useful to identify groundwater discharge zones in summer and spring......-term deployment covering variable meteorological and hydrological scenarios. Copyright © 2012 John Wiley & Sons, Ltd....

  18. Groundwater Radioiodine: Prevalence, Biogeochemistry, And Potential Remedial Approaches

    International Nuclear Information System (INIS)

    Denham, M.; Kaplan, D.; Yeager, C.

    2009-01-01

    Iodine-129 ( 129 I) has not received as much attention in basic and applied research as other contaminants associated with DOE plumes. These other contaminants, such as uranium, plutonium, strontium, and technetium are more widespread and exist at more DOE facilities. Yet, at the Hanford Site and the Savannah River Site 129 I occurs in groundwater at concentrations significantly above the primary drinking water standard and there is no accepted method for treating it, other than pump-and-treat systems. With the potential arrival of a 'Nuclear Renaissance', new nuclear power facilities will be creating additional 129 I waste at a rate of 1 Ci/gigawatts energy produced. If all 22 proposed nuclear power facilities in the U.S. get approved, they will produce more 129 I waste in seven years than presently exists at the two facilities containing the largest 129 I inventories, (∼146 Ci 129 I at the Hanford Site and the Savannah River Site). Hence, there is an important need to fully understand 129 I behavior in the environment to clean up existing plumes and to support the expected future expansion of nuclear power production. 129 I is among the key risk drivers at all DOE nuclear disposal facilities where 129 I is buried, because of its long half-life (16 million years), high toxicity (90% of the body's iodine accumulates in the thyroid), high inventory, and perceived high mobility in the subsurface environment. Another important reason that 129 I is a key risk driver is that there is the uncertainty regarding its biogeochemical fate and transport in the environment. We typically can define 129 I mass balance and flux at sites, but can not accurately predict its response to changes in the environment. This uncertainty is in part responsible for the low drinking water standard, 1 pCi/L 129 I, and the low permissible inventory limits (Ci) at the Savannah River Site, Hanford Site, and the former Yucca Mountain disposal facilities. The objectives of this report are to: (1

  19. GROUNDWATER RADIOIODINE: PREVALENCE, BIOGEOCHEMISTRY, AND POTENTIAL REMEDIAL APPROACHES

    Energy Technology Data Exchange (ETDEWEB)

    Denham, M.; Kaplan, D.; Yeager, C.

    2009-09-23

    Iodine-129 ({sup 129}I) has not received as much attention in basic and applied research as other contaminants associated with DOE plumes. These other contaminants, such as uranium, plutonium, strontium, and technetium are more widespread and exist at more DOE facilities. Yet, at the Hanford Site and the Savannah River Site {sup 129}I occurs in groundwater at concentrations significantly above the primary drinking water standard and there is no accepted method for treating it, other than pump-and-treat systems. With the potential arrival of a 'Nuclear Renaissance', new nuclear power facilities will be creating additional {sup 129}I waste at a rate of 1 Ci/gigawatts energy produced. If all 22 proposed nuclear power facilities in the U.S. get approved, they will produce more {sup 129}I waste in seven years than presently exists at the two facilities containing the largest {sup 129}I inventories, ({approx}146 Ci {sup 129}I at the Hanford Site and the Savannah River Site). Hence, there is an important need to fully understand {sup 129}I behavior in the environment to clean up existing plumes and to support the expected future expansion of nuclear power production. {sup 129}I is among the key risk drivers at all DOE nuclear disposal facilities where {sup 129}I is buried, because of its long half-life (16 million years), high toxicity (90% of the body's iodine accumulates in the thyroid), high inventory, and perceived high mobility in the subsurface environment. Another important reason that {sup 129}I is a key risk driver is that there is the uncertainty regarding its biogeochemical fate and transport in the environment. We typically can define {sup 129}I mass balance and flux at sites, but can not accurately predict its response to changes in the environment. This uncertainty is in part responsible for the low drinking water standard, 1 pCi/L {sup 129}I, and the low permissible inventory limits (Ci) at the Savannah River Site, Hanford Site, and the

  20. 14C age reassessment of groundwater from the discharge zone due to cross-flow mixing in the deep confined aquifer

    Science.gov (United States)

    Mao, Xumei; Wang, Hua; Feng, Liang

    2018-05-01

    In a groundwater flow system, the age of groundwater should gradually increase from the recharge zone to the discharge zone within the same streamline. However, it is occasionally observed that the groundwater age becomes younger in the discharge zone in the piedmont alluvial plain, and the oldest age often appears in the middle of the plain. A new set of groundwater chemistry and isotopes was employed to reassess the groundwater 14C ages from the discharge zone in the North China Plain (NCP). Carbonate precipitation, organic matter oxidation and cross-flow mixing in the groundwater from the recharge zone to the discharge zone are recognized according to the corresponding changes of HCO3- (or DIC) and δ13C in the same streamline of the third aquifer of the NCP. The effects of carbonate precipitation and organic matter oxidation are calibrated with a 13C mixing model and DIC correction, but these corrected 14C ages seem unreasonable because they grow younger from the middle plain to the discharge zone in the NCP. The relationship of Cl- content and the recharge distance is used to estimate the expected Cl- content in the discharge zone, and ln(a14C)/Cl is proposed to correct the a14C in groundwater for the effect of cross-flow mixing. The 14C ages were reassessed with the corrected a14C due to the cross-flow mixing varying from 1.25 to 30.58 ka, and the groundwater becomes older gradually from the recharge zone to the discharge zone. The results suggest that the reassessed 14C ages are more reasonable for the groundwater from the discharge zone due to cross-flow mixing.

  1. Regional Survey of Structural Properties and Cementation Patterns of Fault Zones in the Northern Part of the Albuquerque Basin, New Mexico - Implications for Ground-Water Flow

    Science.gov (United States)

    Minor, Scott A.; Hudson, Mark R.

    2006-01-01

    Motivated by the need to document and evaluate the types and variability of fault zone properties that potentially affect aquifer systems in basins of the middle Rio Grande rift, we systematically characterized structural and cementation properties of exposed fault zones at 176 sites in the northern Albuquerque Basin. A statistical analysis of measurements and observations evaluated four aspects of the fault zones: (1) attitude and displacement, (2) cement, (3) lithology of the host rock or sediment, and (4) character and width of distinctive structural architectural components at the outcrop scale. Three structural architectural components of the fault zones were observed: (1) outer damage zones related to fault growth; these zones typically contain deformation bands, shear fractures, and open extensional fractures, which strike subparallel to the fault and may promote ground-water flow along the fault zone; (2) inner mixed zones composed of variably entrained, disrupted, and dismembered blocks of host sediment; and (3) central fault cores that accommodate most shear strain and in which persistent low- permeability clay-rich rocks likely impede the flow of water across the fault. The lithology of the host rock or sediment influences the structure of the fault zone and the width of its components. Different grain-size distributions and degrees of induration of the host materials produce differences in material strength that lead to variations in width, degree, and style of fracturing and other fault-related deformation. In addition, lithology of the host sediment appears to strongly control the distribution of cement in fault zones. Most faults strike north to north-northeast and dip 55? - 77? east or west, toward the basin center. Most faults exhibit normal slip, and many of these faults have been reactivated by normal-oblique and strike slip. Although measured fault displacements have a broad range, from 0.9 to 4,000 m, most are internal structure of, and cement

  2. Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995

    Energy Technology Data Exchange (ETDEWEB)

    Luckey, R.R.; Tucci, P.; Faunt, C.C.; Ervin, E.M. [and others

    1996-12-31

    Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data.

  3. Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995

    International Nuclear Information System (INIS)

    Luckey, R.R.; Tucci, P.; Faunt, C.C.; Ervin, E.M.

    1996-01-01

    Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data

  4. Detailing new and emerging groundwater pollutants and their potential risk to groundwater environments

    OpenAIRE

    Stuart, Marianne; Lapworth, Dan; Manamsa, Katya

    2014-01-01

    Many different sources and pathways into groundwater: wastewater, biosolids from water treatment and animal wastes are important Frequently detected groups of ECs include antimicrobials, lifestyle compounds, pharmaceuticals Although mostly detected in low ng/L concentrations in groundwater there are many examples of hot spots TPs can be found at concentrations higher than the parent and may be more mobile or polar, and more toxic ECs can be typical of source/landuse Some are re...

  5. Potential of arid zone vegetation as a source of substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bassham, J.A.

    1977-11-01

    Three aspects of the potential of vegetation in arid zones as a source of substrates are discussed. The first includes the limitations on efficiency of conversion of solar energy to the stored chemical energy of biomass in green plants, and the subsequent biochemical pathways of carbon dioxide fixation and biosynthesis. Second is the potential of plants endogenous to arid zones. Finally, the use of covered agriculture or controlled environmental agriculture (CEA) is considered both in its present form and in terms of possible extenion to the large scale production of stable crops. (JGB)

  6. The use of unsaturated zone solutes and deuterium profiles in the study of groundwater recharge in the semi-arid zone of Nigeria

    International Nuclear Information System (INIS)

    Goni, I.B.; Edmunds, W.M.

    2001-01-01

    Two unsaturated zone profiles (MF and MG) in NE Nigeria have been sampled for inert tracers (Cl, Br, NO 3 and δ 2 H to investigate recharge rates and processes. The upper MF and MG profiles have sandy lithology, lower moisture content ( 2 H around -30 per mille. All these indicate that present day recharge is taking place. The lower section of the MF profile shows a distinct contrast with high moisture content (up to 27%), very high chloride (average 2892 mg/L) and relatively enriched deuterium (-12 per mille), indicating the effect of evaporative enrichment. This lower section corresponds to low permeability lacustrine deposits probably representing the former bed of Lake Chad where little or no infiltration has been occurring since the mid-Holocene when the lake extended over this area. The sand-covered areas of the Sahel of the NE Nigeria provide an important phreatic aquifer. An estimation of the amount of recharge using the unsaturated zone chloride mass balance gives significant rates of 14 mm/a and 22 mm/a for the upper MF and MG profiles respectively. These rates mainly span the period of the recent Sahel drought and even higher recharge rates may occur during wetter periods. These rates fall within the 14 mm/a to 53 mm/a range estimated for the Manga Grasslands area in the NE Nigeria obtained in an earlier study. From the water resource point of view, the region has potential for perennially-recharged groundwater resources that can sustain the present abstraction level which is mainly via dug wells. (author)

  7. Use of Interface Treatment to Reduce Emissions from Residuals in Lower Permeability Zones to Groundwater flowing Through More Permeable Zones (Invited)

    Science.gov (United States)

    Johnson, P.; Cavanagh, B.; Clifton, L.; Daniels, E.; Dahlen, P.

    2013-12-01

    Many soil and groundwater remediation technologies rely on fluid flow for contaminant extraction or reactant delivery (e.g., soil vapor extraction, pump and treat, in situ chemical oxidation, air sparging, enhanced bioremediation). Given that most unconsolidated and consolidated settings have permeability contrasts, the outcome is often preferential treatment of more permeable zones and ineffective treatment of the lower permeability zones. When this happens, post-treatment contaminant emissions from low permeability zone residuals can cause unacceptable long-term impacts to groundwater in the transmissive zones. As complete remediation of the impacted lower permeability zones may not be practicable with conventional technologies, one might explore options that lead to reduction of the contaminant emissions to acceptable levels, rather than full remediation of the lower permeability layers. This could be accomplished either by creating a sustained emission reaction/attenuation zone at the high-low permeability interface, or by creating a clean soil zone extending sufficiently far into the lower permeability layer to cause the necessary reduction in contaminant concentration gradient and diffusive emission. These options are explored in proof-of-concept laboratory-scale physical model experiments. The physical models are prepared with two layers of contrasting permeability and either dissolved matrix storage or nonaqueous phase liquid (NAPL) in the lower permeability layer. A dissolved oxidant is then delivered to the interface via flow across the higher permeability layer and changes in contaminant emissions from the low permeability zone are monitored before, during, and after oxidant delivery. The use of three oxidants (dissolved oxygen, hydrogen peroxide and sodium persulfate) for treatment of emissions from petroleum hydrocarbon residuals is examined.

  8. Geo-Electrical Investigation for Groundwater Potential of Ihievbe ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2017-12-10

    Dec 10, 2017 ... Keywords: Groundwater, Vertical Electrical Sounding, Fractured basement, prospectively ranking. The ease of ... magnetic, electromagnetic etc. Of all these ... ranking, to aid our interpretation and evaluation of the ground ...

  9. electrical resistivity investigation of the groundwater potential in ...

    African Journals Online (AJOL)

    The VES data generated were processed and interpreted using partial curve matching ... electrical sounding, a technique of electrical resistivity method in identifying viable .... Geoelectric/Electromagnetic VLF Survey for. Groundwater in a ...

  10. Review of risk from potential emerging contaminants in UK groundwater

    OpenAIRE

    Stuart, Marianne; Lapworth, Dan; Crane, Emily; Hart, Alwyn

    2012-01-01

    This paper provides a review of the types of emerging organic groundwater contaminants (EGCs) which are beginning to be found in the UK. EGCs are compounds being found in groundwater that were previously not detectable or known to be significant and can come from agricultural, urban and rural point sources. EGCs include nanomaterials, pesticides, pharmaceuticals, industrial compounds, personal care products, fragrances, water treatment by-products, flame retardants and surfactants, as well a...

  11. Developing a methodology for identifying action zones to protect and manage groundwater well fields

    Science.gov (United States)

    Bellier, Sandra; Viennot, Pascal; Ledoux, Emmanuel; Schott, Celine

    2013-04-01

    Implementation of a long term action plan to manage and protect well fields is a complex and very expensive process. In this context, the relevance and efficiency of such action plans on water quality should be evaluated. The objective of this study is to set up a methodology to identify relevant actions zones in which environmental changes may significantly impact the quantity or quality of pumped water. In the Seine-et-Marne department (France), under French environmental laws three sectors integrating numerous well-field pumping in Champigny's limestone aquifer are considered as priority. This aquifer, located at south-east of Paris, supplies more than one million people with drinking water. Catchments areas of these abstractions are very large (2000 km2) and their intrinsic vulnerability was established by a simple parametric approach that does not permit to consider the complexity of hydrosystem. Consequently, a methodology based on a distributed modeling of the process of the aquifer was developed. The basin is modeled using the hydrogeological model MODCOU, developed in MINES ParisTech since the 1980s. It simulates surface and groundwater flow in aquifer systems and allows to represent the local characteristics of the hydrosystem (aquifers communicating by leakage, rivers infiltration, supply from sinkholes and locally perched or dewatering aquifers). The model was calibrated by matching simulated river discharge hydrographs and piezometric heads with observed ones since the 1970s. Thanks to this modelling tool, a methodology based on the transfer of a theoretical tracer through the hydrosystem from the ground surface to the outlets was implemented to evaluate the spatial distribution of the contribution areas at contrasted, wet or dry recharge periods. The results show that the surface of areas contributing to supply most catchments is lower than 300 km2 and the major contributory zones are located along rivers. This finding illustrates the importance of

  12. [Relationship between groundwater quality index of nutrition element and organic matter in riparian zone and water quality in river].

    Science.gov (United States)

    Hua-Shan, Xu; Tong-Qian, Zhao; Hong-Q, Meng; Zong-Xue, Xu; Chao-Hon, Ma

    2011-04-01

    Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that there will be great risk of nitrogen, phosphorus, nitrate nitrogen and organic matter permeating into the groundwater if floodplain changes into farmland. As the special control unit of nitrogen pollution between rivers and artificial wetlands, dry fanning areas near the river play a very important role in nitrogen migration between river and groundwater. Farm manure as base fertilizer may he an important source of phosphorus leak and loss at the artificial wetlands. Phosphorus leaks into the groundwater and is transferred along the hydraulic gradient, especially during the period of regulation for water and sediment at the Xiaolangdi Reservoir. The land use types and farming systems of the riparian floodplain have a major impact on the nitrate nitrogen contents of the groundwater. Nitrogen can infiltrate and accumulate quickly at anaerobic conditions in the fish pond area, and the annual nitrogen achieves a relatively balanced state in lotus area. In those areas, the soil is flooded and at anaerobic condition in spring and summer, nitrogen infiltrates and denitrification significantly, but soil is not flooded and at aerobic condition in the autumn and winter, and during these time, a significant nitrogen nitrification process occurs. In the area between 50 m and 200 m from the river

  13. Delineation of ground water potential zones using GIS and remote sensing - A case study from midland region of Vamanapuram river basin, Kerala, India

    Science.gov (United States)

    Prasad, Geena; Vinod P., G.; John, Shaleena Elizabeth

    2018-04-01

    In a highly rugged terrain, shielded by hard crystalline rocks like that of Kerala, locating potential zones of groundwater is found to be an unenviable task. Remote sensing and Geographical information system technologies have been attempted widely to delineate the potential regions in such terrain. Geographical information system tool has been used for delineation of groundwater prospect zones in midland physiographic zone (30-200m) of Vamanapuram river basin. The terrain variables are generated using satellite imageries, SRTM DEM data of 30m resolution and SOI toposheets. The groundwater prospect zones were delineated through the integration of the reclassified raster map layers of geomorphology, slope percent, geology, land use / land cover and soil texture using the weighted overlay analysis in the GIS platform. The groundwater prospects in the study area were grouped into five classes and their distribution are; `very high/high' (8.79%), `moderate' (39.08%), and `very low / low' (52.01%). The study result of the area has been validated with water level data of dug wells and bore wells of the area. The spatial distribution map of the water level of the region is overlaid on groundwater prospect map and shows a positive correlation i.e., the water level at shallow depth in higher prospect zones and at deeper depth in poor to very poor zones. The Groundwater prospect map of midland region of Vamanapuram river basin can be used as base level information which can be further investigated with geophysical methods to locate potential well sites for the execution of water supply schemes.

  14. Transport and potential attenuation of nitrogen in shallow groundwaters in the lower Rangitikei catchment, New Zealand

    Science.gov (United States)

    Collins, S.; Singh, R.; Rivas, A.; Palmer, A.; Horne, D.; Manderson, A.; Roygard, J.; Matthews, A.

    2017-11-01

    Intensive agricultural activities are generally associated with nitrogen leaching from agricultural soils, and this nitrogen has the potential to percolate and contaminate groundwater and surface waters. We assessed surface water and groundwater interactions, and nitrogen leaching and its potential attenuation in shallow groundwater in the lower Rangitikei River catchment (832 km2), New Zealand. We combined regional- and local-scale field surveys and experiments, nutrient budget modelling, and hydraulic and geochemical methods, to gain an insight into leaching, transformation and transport of nitrogen via groundwaters to the river in the study area. Concurrent river flow gaugings (in January 2015) and a piezometric map, developed from measured depths to groundwater in 110 bores (in October 2014), suggest groundwater discharges to the Rangitikei River in the upper parts of the study area, while there is groundwater recharge near the coast. The groundwater redox characterisation, based on sampling and analysis of 15 mostly shallow bores ( 5 m bgl), despite being installed under intensive land uses, such as dairying and cropping. Our in-field push-pull tests showed NO3-N reduction at four shallow groundwater piezometers, with the rates of reduction varying from 0.04 mg N L- 1 h-1 to 1.57 mg N L- 1 h-1. This highlights the importance of a sound understanding of not only the sources, but also transport and transformation, or fate, of nutrients leached from farms, to mitigate the likely impacts of land use on water quality and ecosystem health in agricultural catchments.

  15. Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley

    DEFF Research Database (Denmark)

    Mikucki, J. A.; Auken, E.; Tulaczyk, S.

    2015-01-01

    The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsu...

  16. A Commune-Level Groundwater Potential Map for the Republic of Mali

    Directory of Open Access Journals (Sweden)

    Silvia Díaz-Alcaide

    2017-10-01

    Full Text Available Groundwater represents an essential resource in sub-Saharan Africa, where several hundred million people rely on aquifers for domestic supply. This paper presents a method to map groundwater potential in the Republic of Mali based on a spatially-distributed database of 26,040 boreholes. The database includes exhaustive information on key parameters such as borehole location, success rate of borehole production, depth, yield, static groundwater level or water quality. Representative variables were classified and interpreted jointly to develop a groundwater potential index for each of the 703 communes in Mali. This provides a methodological novelty because groundwater potential studies typically rely on indirect indicators such as lineaments, slope, soil moisture and landforms. Also, such large borehole databases have seldom been used to estimate groundwater potential. The highest indexes were obtained for the areas in and around the River Niger’s Inner Delta, including southern Tombouctou and the central parts of the Ségou and Mopti Regions. The lower Precambrian formations, which include the country’s thoroughly populated southern plateau, had moderate scores. The lowest groundwater potential was found in the northern part of the Kayes and Koulikoro Regions, as well as in the entire region of Kidal. By providing results at the commune scale, these outcomes show that groundwater potential across the country’s geological and hydrogeological units can be highly variable, and that local and regional-scale information may be useful for groundwater management purposes. These results are policy-relevant in a context of rapid change and population growth, where groundwater resources can be expected to be increasingly relied upon in the coming years.

  17. Time Lapse Electrical Resistivity to Connect Evapotranspiration and Groundwater Fluxes in the Critical Zone

    Science.gov (United States)

    Jarvis, S. K.; Harmon, R. E.; Barnard, H. R.; Randall, J.; Singha, K.

    2017-12-01

    The critical zone (CZ)—an open system extending from canopy top to the base of groundwater—is a highly dynamic and heterogeneous environment. In forested terrain, trees make up a large component of the CZ. This work aims to quantify the connection between vegetation and subsurface water storage at a hillslope scale within a forested watershed in the H.J. Andrews Experimental Forest, Oregon. To identify the mechanism(s) controlling the connection at the hillslope scale, we observe patterns in electrical conductivity using 2D-time lapse-DC resistivity. To compare inversions through time a representative error model was determined using L-curve criterion. Inverted data show high spatial variability in ground electrical conductivity and variation at both diel and seasonal timescales. These changes are most pronounced in areas corresponding to dense vegetation. The diel pattern in electrical conductivity is also observed in monitored sap flow sensors, water-level gauges, tensiometers, and sediment thermal probes. To quantify the temporal connection between these data over the course of the growing season a cross correlation analysis was conducted. Preliminary data show that over the course of the growing season transpiration becomes decoupled from both groundwater and soil moisture. Further decomposition of the inverted time lapse data will highlight spatial variability in electrical conductivity providing insight into the where, when, and how(s) of tree-modified subsurface storage.

  18. Regional and Detailed Survey for Radon Activities in Soil-Gas and Groundwater in the Okchon Zone, Korea

    Science.gov (United States)

    Je, H.-K.; Chon, H.-T.

    2012-04-01

    The Okchon zone in Korea provides a typical example of natural geological materials enriched in potentially toxic elements including uranium which is parent nuclide for radon gas. For the purpose of radon radioactivity risk assessment, making the map of radon risk grade from Okchon zone, regional and detailed field surveys were carried out during 3 years. The study area is located in the central part of Korea, called the Okchon zone (about 5,100 km2), which occur in a 80km wide, northeast-trending belt that extends across the Korean Peninsula. The Okchon zone is underlain by metasedimentary rocks of unknown age that are composed mainly of black slate, phyllite, shale, and limestone. The three research areas (defined as Boeun, Chungju, and Nonsan) for detailed survey were selected from the results of regional survey. Results of detailed radon survey indicated a wide range of radon activities for soil-gases (148-1,843 pCi/L) and ground waters (23-5,540 pCi/L). About 15 percent of soil-gas samples exceeded 1,000 pCi/L and 84 percent of ground water samples exceeded the MCL (maximum contaminant level) of drinking water, 300 pCi/L, which proposed by U.S. Environmental Protection Agency in 1999. For detailed survey, radon activities of soil-gas and ground water were classified as bedrock geology, based on 1/50,000 geological map and field research. For soil-gas measurements, mean values of radon activity from black slate-shale (789 pCi/L) were highest among the other base rocks. And for groundwater measurements, mean value of radon activities were decreased in the order of granite (1,345 pCi/L) > black shale-slate (915 pCi/L) > metasediments (617 pCi/L). Result of indoor radon measurement from detailed survey areas showed that about 50% of houses exceeded the indoor guideline, 4 pCi/L. For the radon risk assessment in indoor environment showed that probability of lung cancer risk from the houses located on the granite base rock (3.0×10-2) was highest among the other

  19. Three-dimensional modeling of nitrate-N transport in vadose zone: Roles of soil heterogeneity and groundwater flux

    Science.gov (United States)

    Akbariyeh, Simin; Bartelt-Hunt, Shannon; Snow, Daniel; Li, Xu; Tang, Zhenghong; Li, Yusong

    2018-04-01

    Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone. In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center pivot-irrigated corn field on Nebraska Management System Evaluation area over a three-year period. The model was based on a realistic three-dimensional sediment lithology, as well as carefully controlled irrigation and fertilizer application plans. In parallel, a homogeneous soil domain, containing the major sediment type of the site (i.e. sandy loam), was developed to conduct the same water flow and nitrate-N leaching simulations. Simulated nitrate-N concentrations were compared with the monitored nitrate-N concentrations in 10 multi-level sampling wells over a three-year period. Although soil heterogeneity was mainly observed from top soil to 3 m below the surface, heterogeneity controlled the spatial distribution of nitrate-N concentration. Soil heterogeneity, however, has minimal impact on the total mass of nitrate-N in the domain. In the deeper saturated zone, short-term variations of nitrate-N concentration correlated with the groundwater level fluctuations.

  20. Conceptual and numerical models of groundwater flow and solute transport in fracture zones: Application to the Aspo Island (Sweden)

    International Nuclear Information System (INIS)

    Molinero, J.; Samper, J.

    2003-01-01

    Several countries around the world are considering the final disposal of high-level radioactive waste in deep repositories located in fractured granite formations. Evaluating the long term safety of such repositories requires sound conceptual and numerical models which must consider simultaneously groundwater flow, solute transport and chemical and radiological processes. These models are being developed from data and knowledge gained from in situ experiments carried out at deep underground laboratories such as that of Aspo, Sweden, constructed in fractured granite. The Redox Zone Experiment is one of such experiments performed at Aspo in order to evaluate the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Previous authors interpreted hydrochemical and isotopic data of this experiment using a mass-balance approach based on a qualitative description of groundwater flow conditions. Such an interpretation, however, is subject to uncertainties related to an over-simplified conceptualization of groundwater flow. Here we present numerical models of groundwater flow and solute transport for this fracture zone. The first model is based on previously published conceptual model. It presents noticeable un consistencies and fails to match simultaneously observed draw downs and chloride breakthrough curves. To overcome its limitations, a revised flow and transport model is presented which relies directly on available hydrodynamic and transport parameters, is based on the identification of appropriate flow and transport boundary conditions and uses, when needed, solute data extrapolated from nearby fracture zones. A significant quantitative improvement is achieved with the revised model because its results match simultaneously drawdown and chloride data. Other improvements are qualitative and include: ensuring consistency of hydrodynamic and hydrochemical data and avoiding

  1. A Low-Level Real-Time In Situ Monitoring System for Tritium in Groundwater and Vadose Zone

    Science.gov (United States)

    Santo, J. T.; Levitt, D. G.

    2002-12-01

    Tritium is a radioactive isotope of hydrogen produced as a by-product of the nuclear fuel cycle. It is also an integral part of the nuclear weapons industry and has been released into the environment through both the production and testing of nuclear weapons. There are many sites across the DOE complex where tritium has been released into the subsurface through the disposal of radioactive waste and at the Nevada Test Site, through the underground testing of nuclear weapons. Numerous DOE facilities have an on-going regulatory need to be able to monitor tritium concentrations in groundwater within deep hydrologic zones and in the shallower non-saturated vadose zone beneath waste disposal pits and shafts and other release sites. Typical access to groundwater is through deep monitoring wells and situated in remote locations. In response to this need, Science and Engineering Associates, Inc. (SEA) and its subcontractor, the University of Nevada Las Vegas (UNLV) Harry Reid Center (HRC) for Environmental Studies has conducted the applied research and engineering and produced a real time, in situ monitoring system for the detection and measurement of low levels of tritium in the groundwater and in the shallower vadose zone. The monitoring system has been deployed to measure tritium in both the vadose zone near a subsurface radioactive waste package and the groundwater in a deep hydrologic reservoir at the Nevada Test Site. The monitoring system has been designed to detect tritium in the subsurface below federal and/or state regulatory limits for safe drinking water and has been successfully demonstrated. The development effort is being funded through the U.S. Department of Energy, National Energy Technology Laboratory and the DOE Nevada Operations Office Advanced Monitoring Systems Initiative (AMSI).

  2. Vertical electrical sounding to delineate the potential aquifer zones ...

    Indian Academy of Sciences (India)

    Joy Choudhury

    2017-09-06

    fed irrigation, etc. The ... position is important for optimum groundwater ... regional scale to estimate natural groundwater ... lithology with depth by means of measured resis- .... stratification for all the VES survey carried out in.

  3. Transport and potential attenuation of nitrogen in shallow groundwaters in the lower Rangitikei catchment, New Zealand.

    Science.gov (United States)

    Collins, S; Singh, R; Rivas, A; Palmer, A; Horne, D; Manderson, A; Roygard, J; Matthews, A

    2017-11-01

    Intensive agricultural activities are generally associated with nitrogen leaching from agricultural soils, and this nitrogen has the potential to percolate and contaminate groundwater and surface waters. We assessed surface water and groundwater interactions, and nitrogen leaching and its potential attenuation in shallow groundwater in the lower Rangitikei River catchment (832km 2 ), New Zealand. We combined regional- and local-scale field surveys and experiments, nutrient budget modelling, and hydraulic and geochemical methods, to gain an insight into leaching, transformation and transport of nitrogen via groundwaters to the river in the study area. Concurrent river flow gaugings (in January 2015) and a piezometric map, developed from measured depths to groundwater in 110 bores (in October 2014), suggest groundwater discharges to the Rangitikei River in the upper parts of the study area, while there is groundwater recharge near the coast. The groundwater redox characterisation, based on sampling and analysis of 15 mostly shallow bores (shallow groundwater piezometers (3-6mbgl) using single-well push-pull tests. We found generally low levels (shallow groundwater piezometers (>5mbgl), despite being installed under intensive land uses, such as dairying and cropping. Our in-field push-pull tests showed NO 3 -N reduction at four shallow groundwater piezometers, with the rates of reduction varying from 0.04mgNL -1 h - 1 to 1.57mgNL -1 h - 1 . This highlights the importance of a sound understanding of not only the sources, but also transport and transformation, or fate, of nutrients leached from farms, to mitigate the likely impacts of land use on water quality and ecosystem health in agricultural catchments. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Prediction of Groundwater Quality Improvement Down-Gradient of In Situ Permeable Treatment Barriers and Fully-Remediated Source Zones. ESTCP Cost and Performance Report

    National Research Council Canada - National Science Library

    Johnson, Paul C; Carlson, Pamela M; Dahlen, Paul

    2008-01-01

    In situ permeable treatment barriers (PTB) are designed so that contaminated groundwater flows through an engineered treatment zone within which contaminants are eliminated or the concentrations are significantly reduced...

  5. Potential impacts of climate change and variability on groundwater ...

    African Journals Online (AJOL)

    Aizebeokhai

    768 ... This is largely due to the risk it poses to the environment ... Nigeria, particularly in rural areas which rely on low-cost domestic ... influenced by groundwater flow under or around the dam. ... densely vegetated mangrove swamps in the south,.

  6. Application of isotopes to the assessment of pollutant behaviour in the unsaturated zone for groundwater protection. Final report of a coordinated research project 2004-2005

    International Nuclear Information System (INIS)

    2009-05-01

    A coordinated research project (CRP) was conducted by the IAEA with the purpose of studying what isotopic and other ancillary data are required to help understand migration of potential contaminants through the unsaturated zone (UZ) into the underlying groundwater. To this end, research projects were conducted in ten countries to study recharge and infiltration processes, as well as contaminant migration in a wide variety of UZ environments. This publication contains the reports of these ten projects and a summary of the accomplishments of the individual projects. The IAEA-TECDOC reviews the usefulness and current status of application of the combined use of isotope and other hydrogeochemical tools for the assessment of flow and transport processes in the UZ. A number of isotope and hydrochemical tools have been used to simultaneously study groundwater recharge and transport of pollutants in the UZ. This information is relevant for assessing the vulnerability of groundwater to contamination. The ten projects covered climates ranging from humid to arid, and water table depths from the near surface to over 600 m. The studies included measuring movement of water, solutes, and gases through the UZ using an assortment of isotope and geochemical tracers and approaches. Contaminant issues have been studied at most of the ten sites and the UZ was found to be very effective in protecting groundwater from most heavy metal contaminants. The publication is expected to be of interest to hydrologists, hydrogeologists and soil scientists dealing with pollution aspects and protection of groundwater resources, as well as counterparts of TC projects in Member States

  7. Gravity-driven groundwater flow and slope failure potential: 1. Elastic effective-stress model

    Science.gov (United States)

    Iverson, Richard M.; Reid, Mark E.

    1992-01-01

    Hilly or mountainous topography influences gravity-driven groundwater flow and the consequent distribution of effective stress in shallow subsurface environments. Effective stress, in turn, influences the potential for slope failure. To evaluate these influences, we formulate a two-dimensional, steady state, poroelastic model. The governing equations incorporate groundwater effects as body forces, and they demonstrate that spatially uniform pore pressure changes do not influence effective stresses. We implement the model using two finite element codes. As an illustrative case, we calculate the groundwater flow field, total body force field, and effective stress field in a straight, homogeneous hillslope. The total body force and effective stress fields show that groundwater flow can influence shear stresses as well as effective normal stresses. In most parts of the hillslope, groundwater flow significantly increases the Coulomb failure potential Φ, which we define as the ratio of maximum shear stress to mean effective normal stress. Groundwater flow also shifts the locus of greatest failure potential toward the slope toe. However, the effects of groundwater flow on failure potential are less pronounced than might be anticipated on the basis of a simpler, one-dimensional, limit equilibrium analysis. This is a consequence of continuity, compatibility, and boundary constraints on the two-dimensional flow and stress fields, and it points to important differences between our elastic continuum model and limit equilibrium models commonly used to assess slope stability.

  8. Assessing biosynthetic potential of agricultural groundwater through metagenomic sequencing: A diverse anammox community dominates nitrate-rich groundwater.

    Directory of Open Access Journals (Sweden)

    William B Ludington

    Full Text Available Climate change produces extremes in both temperature and precipitation causing increased drought severity and increased reliance on groundwater resources. Agricultural practices, which rely on groundwater, are sensitive to but also sources of contaminants, including nitrate. How agricultural contamination drives groundwater geochemistry through microbial metabolism is poorly understood.On an active cow dairy in the Central Valley of California, we sampled groundwater from three wells at depths of 4.3 m (two wells and 100 m (one well below ground surface (bgs as well as an effluent surface water lagoon that fertilizes surrounding corn fields. We analyzed the samples for concentrations of solutes, heavy metals, and USDA pathogenic bacteria of the Escherichia coli and Enterococcus groups as part of a long term groundwater monitoring study. Whole metagenome shotgun sequencing and assembly revealed taxonomic composition and metabolic potential of the community.Elevated nitrate and dissolved organic carbon occurred at 4.3m but not at 100m bgs. Metagenomics confirmed chemical observations and revealed several Planctomycete genomes, including a new Brocadiaceae lineage and a likely Planctomycetes OM190, as well novel diversity and high abundance of nano-prokaryotes from the Candidate Phyla Radiation (CPR, the Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, Nanohaloarchaea (DPANN and the Thaumarchaeota, Aigarchaeota, Crenarchaeota, Korarchaeota (TACK superphyla. Pathway analysis suggests community interactions based on complimentary primary metabolic pathways and abundant secondary metabolite operons encoding antimicrobials and quorum sensing systems.The metagenomes show strong resemblance to activated sludge communities from a nitrogen removal reactor at a wastewater treatment plant, suggesting that natural bioremediation occurs through microbial metabolism. Elevated nitrate and rich secondary metabolite biosynthetic capacity suggest

  9. Terrestrial sedimentary pyrites as a potential source of trace metal release to groundwater – A case study from the Emsland, Germany

    International Nuclear Information System (INIS)

    Houben, Georg J.; Sitnikova, Maria A.; Post, Vincent E.A.

    2017-01-01

    Pyrite is a common minor constituent of terrestrial freshwater sediments and a sink for trace elements. Different amounts and morphological types (framboids and euhedral crystals) of sedimentary pyrites were found in the heavy mineral fraction of cores obtained from several drillholes located in the Emsland region, NW Germany. Their trace element contents were investigated to assess their potential for groundwater contamination after oxidation, e.g. induced by dewatering or autotrophic denitrification. Nickel, arsenic and cadmium were found in significant concentrations in pyrite. Geochemical modeling showed that elevated trace metal concentrations in groundwater, potentially exceeding drinking water standards, should preferentially occur in a less than 1 m thick zone situated around the depth of the redoxcline, where nitrate is reduced by pyrite. This was confirmed by depth-specific groundwater sampling in the Emsland and by previously published studies. The absolute concentration of released trace metals depends on their content in the pyrite but also strongly on the nitrate load of groundwater. - Highlights: • Pyrite from heavy mineral fraction of aquifer sediment analyzed for trace metal content. • Pyrites contain significant concentration of trace metals, such as nickel, arsenic, cadmium. • Trace elements are released by autotrophic denitrification. • Reactive transport model predicts small zone of trace element accumulation. • Release of trace elements strongly dependent on nitrate content of groundwater.

  10. Electromagnetic exploration in high-salinity groundwater zones: case studies from volcanic and soft sedimentary sites in coastal Japan

    Science.gov (United States)

    Suzuki, Koichi; Kusano, Yukiko; Ochi, Ryota; Nishiyama, Nariaki; Tokunaga, Tomochika; Tanaka, Kazuhiro

    2017-01-01

    Estimating the spatial distribution of groundwater salinity in coastal plain regions is becoming increasingly important for site characterisation and the prediction of hydrogeological environmental conditions resulting from radioactive waste disposal and underground CO2 storage. In previous studies of the freshwater-saltwater interface, electromagnetic methods were used for sites characterised by unconsolidated deposits or Neocene soft sedimentary rocks. However, investigating the freshwater-saltwater interface in hard rock sites (e.g. igneous areas) is more complex, with the permeability of the rocks greatly influenced by fractures. In this study, we investigated the distribution of high-salinity groundwater at two volcanic rock sites and one sedimentary rock site, each characterised by different hydrogeological features. Our investigations included (1) applying the controlled source audio-frequency magnetotelluric (CSAMT) method and (2) conducting laboratory tests to measure the electrical properties of rock core samples. We interpreted the 2D resistivity sections by referring to previous data on geology and geochemistry of groundwater. At the Tokusa site, an area of inland volcanic rocks, low resistivity zones were detected along a fault running through volcanic rocks and shallow sediments. The results suggest that fluids rise through the Tokusa-Jifuku Fault to penetrate shallow sediments in a direction parallel to the river, and some fluids are diluted by rainwater. At the Oki site, a volcanic island on a continental shelf, four resistivity zones (in upward succession: low, high, low and high) were detected. The results suggest that these four zones were formed during a transgression-regression cycle caused by the last glacial period. At the Saijo site, located on a coastal plain composed of thick sediments, we observed a deep low resistivity zone, indicative of fossil seawater remnant from a transgression after the last glacial period. The current coastal

  11. Assessment of underground water potential zones using modern geomatics technologies in Jhansi district, Uttar Pradesh, India.

    Science.gov (United States)

    Pandey, N. K.; Shukla, A. K.; Shukla, S.; Pandey, M.

    2014-11-01

    Ground water is a distinguished component of the hydrologic cycle. Surface water storage and ground water withdrawal are traditional engineering approaches which will continue to be followed in the future. The uncertainty about the occurrence, distribution and quality aspect of the ground water and the energy requirement for its withdrawal impose restriction on exploitation of ground water. The main objective of the study is assessment of underground water potential zones of Jhansi city and surrounding area, by preparing underground water potential zone map using Geographical Information System (GIS), remote sensing, and validation by underground water inventory mapping using GPS field survey done along the parts of National Highway 25 and 26 and some state highway passing through the study area. Study area covers an area of 1401 km2 and its perimeter is approximate 425 km. For this study Landsat TM (0.76-0.90 um) band data were acquired from GLCF website. Sensor spatial resolution is 30 m. Satellite image has become a standard tool aiding in the study of underground water. Extraction of different thematic layers like Land Use Land Cover (LULC), settlement, etc. can be done through unsupervised classification. The modern geometics technologies viz. remote sensing and GIS are used to produce the map that classifies the groundwater potential zone to a number of qualitative zone such as very high, high, moderate, low or very low. Thematic maps are prepared by visual interpretation of Survey of India topo-sheets and linearly enhanced Landsat TM satellite image on 1 : 50,000 scale using AutoCAD, ArcGIS 10.1 and ERDAS 11 software packages.

  12. Excess air in groundwater as a potential indicator of past environmental changes

    International Nuclear Information System (INIS)

    Aeschenbach-Hertig, W.; Beyerle, U.; Holocher, J.; Peeters, F.; Kipfer, R.

    2002-01-01

    Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also yield information about 'excess air', a component of dissolved gases in excess of solubility equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the excess air component is necessary not only to obtain reliable noble gas temperatures, but also to investigate the potential of excess air as a proxy for past environmental conditions. Two excess air related quantities can be derived from groundwater noble gas data sets: The initial air/water ratio and the pressure exerted on the entrapped air. Under recharge conditions typical for many aquifers, the excess of dissolved gases, expressed by the relative Ne excess ΔNe, is mainly determined by the hydrostatic pressure on the entrapped air. Thus, we suggest that ΔNe is essentially a measure of the amplitude of water table fluctuations in the recharge area. Comparing data sets from three aquifers in temperate, humid latitudes and three aquifers in tropical, semi-arid regions, we find that ΔNe is generally higher in the tropical aquifers, possibly related to larger water table fluctuations in these aquifers characterized by deep unsaturated zones. Whereas ΔNe shows little temporal variation in the mid-latitude aquifers, there is a strong signal of higher ΔNe in the paleowaters of the tropical aquifers as compared to water recharged under modern climate conditions. This finding may indicate a higher variability of recharge in the past at the studied tropical sites. (author)

  13. Integrating hydrogeophysics and hydrological tracers to characterise the spatial structure of groundwater storage in the critical zone of montane environments

    Science.gov (United States)

    Dick, J.; Tetzlaff, D.; Bradford, J.; Soulsby, C.

    2015-12-01

    It is increasingly recognised that groundwater (GW) in montane watersheds has a major influence on the distribution of vegetation communities and ecosystem function, as well as sustaining downstream river flows. In glaciated landscapes, complex and heterogenous drift deposits can have a dominant influence on GW stores and fluxes, and form a poorly understood component of the critical zone. Given the logistical problems and limitations of drilling observation wells in such terrain, hydrogeophysics has outstanding potential to help characterise aquifer structure and understand shallow GW in the critical zone of montane environments. We present the results of electrical resistivity tomography (ERT) surveys in an intensively monitored 3.2km2 watershed in the Scottish Highlands with a strong glacial past. We sought to characterise the structure and spatial organisation of GW stores in diverse quaternary drift deposits. This utilized distributed ERT transects that provided a basis for spatial interpolation using geostatistical methods and high resolution LiDAR surveys. Some transects coincided with shallow observation wells that were used to "ground-truth" the inversion of resistivity data. The surveys showed that the drifts covered around 70% of the catchment and varied from 5m deep on the hillslopes to 40m in the valleys. The water table was within 0.2m of the soil surface in the valley bottom areas and about 1.5m deep on steeper hillslopes. The water content of drifts inferred by the ERT surveys and characterisation of the aquifer properties showed highest water content in the peat (~80%) and basal till (20-30%), and low storage in moraine deposits (10%). Upscaling these estimates of inferred storage to the catchment scale indicated around ~2-3 m of GW storage, equivalent to around 4-6 years of effective precipitation. This generally compared well with independent storage estimates inferred from long-term stable isotope time series collected from the aquifers

  14. Evaluation of groundwater resources potential in the Ejisu-Juaben ...

    African Journals Online (AJOL)

    EJIRO

    African Journal of Environmental Science and Technology Vol. 3 (10), pp. ..... ness of the saturated zone, m; A = hydrogeological basin ∼ extent of the study ..... system southern voltain sedimentary basin of Ghana: An isotopic approach, J.

  15. Potential field signatures along the Zagros collision zone in Iran

    Science.gov (United States)

    Abedi, Maysam; Fournier, Dominique; Devriese, Sarah G. R.; Oldenburg, Douglas W.

    2018-01-01

    The Zagros orogenic belt, known as an active fold-thrust belt, was formed in southwestern Iran due to the convergence of the Arabian and Eurasian plates. In this study, potential field data are inverted in 3D to image the variations of magnetic susceptibility and density contrast along the collision zone, resulting in better tectonic understanding of the studied region. Geophysical data measured by airborne magnetic and ground-based gravity systems are used to construct an integrated model that facilitates the interpretations of various tectonic zones across a 450-km line. This line intersects the main structural units from the SW portion of the Zagros belt. The constructed model reveals a contrast that indicates the transition between the two continental plates coinciding with the western boundaries of the Sanandaj-Sirjan Zone (SSZ) at the Main Zagros Thrust (MZT) fault. The subduction of the Arabian continental crust below the Iranian one is evident because of its lower susceptibility property and alternating sequence of high and low density regions. Higher susceptibility, magnetic remanence and density are the mainstays of the Urumieh-Dokhtar Magmatic Assemblage (UDMA) zone at the NE of the studied route, whereas lower values of these properties correspond to (1) the thin massive Tertiary-Neogene and Quaternary sediments of the central domain (CD) zone, and (2) the thick sedimentary and salt intrusion cover over the Zagros Fold-and-Thrust belt (ZFTB). Higher density of regions in the Arabian crust below the ZFTB implies that fault activities have caused significant vertical displacement of the basement. Finally, a simplified geological model is presented based upon the inversions of the geophysical data, in which the main geological units are divided along the studied route.

  16. Velocity Potential in Engineering Hydraulics versus Force Potential in Groundwater Dynamics

    Science.gov (United States)

    Weyer, K.

    2013-12-01

    Within engineering practice, the calculation of subsurface flow is dominated by the mathematical pseudo-physics of the engineer's adaptation of continuum methods to mechanics. Continuum mechanics rose to prominence in the 19th century in an successful attempt to solve practical engineering problems. To that end were put in place quite a number of simplifications in geometry and the properties of water and other fluids, as well as simplifications of Darcy's equation, in order to find reasonable answers to practical problems by making use of analytical equations. The proof of the correctness of the approach and its usefulness was in the practicability of results obtained. In the 1930s, a diametrically-opposed duality developed in the theoretical derivation of the laws of subsurface fluid flow between Muskat's (1937) velocity potential (engineering hydraulics) and Hubbert's (1940) force potential. The conflict between these authors lasted a lifetime. In the end Hubbert stated on one occasion that Muskat formulates a refined mathematics but does not know what it means in physical terms. In this author's opinion that can still be said about the application of continuum mechanics by engineers to date, as for example to CO2 sequestration, regional groundwater flow, oil sands work, and geothermal studies. To date, engineering hydraulics is best represented by Bear (1972) and de Marsily (1986). In their well-known textbooks, both authors refer to Hubbert's work as the proper way to deal with the physics of compressible fluids. Water is a compressible fluid. The authors then ignore, however, their own insights (de Marsily states so explicitly, Bear does not) and proceed to deal with water as an incompressible fluid. At places both authors assume the pressure gradients to be the main driving force for flow of fluids in the subsurface. That is not, however, the case. Instead the pressure potential forces are caused by compression initiated by unused gravitational energy not

  17. Statistical mapping of zones of focused groundwater/surface-water exchange using fiber-optic distributed temperature sensing

    Science.gov (United States)

    Mwakanyamale, Kisa; Day-Lewis, Frederick D.; Slater, Lee D.

    2013-01-01

    Fiber-optic distributed temperature sensing (FO-DTS) increasingly is used to map zones of focused groundwater/surface-water exchange (GWSWE). Previous studies of GWSWE using FO-DTS involved identification of zones of focused GWSWE based on arbitrary cutoffs of FO-DTS time-series statistics (e.g., variance, cross-correlation between temperature and stage, or spectral power). New approaches are needed to extract more quantitative information from large, complex FO-DTS data sets while concurrently providing an assessment of uncertainty associated with mapping zones of focused GSWSE. Toward this end, we present a strategy combining discriminant analysis (DA) and spectral analysis (SA). We demonstrate the approach using field experimental data from a reach of the Columbia River adjacent to the Hanford 300 Area site. Results of the combined SA/DA approach are shown to be superior to previous results from qualitative interpretation of FO-DTS spectra alone.

  18. Characterizing multiple sources and interaction in the critical zone through Sr-isotope tracing of surface and groundwater

    Science.gov (United States)

    Negrel, Philippe; Pauwels, Hélène

    2017-04-01

    The Critical Zone (CZ) is the lithosphere-atmosphere boundary where complex physical, chemical and biological processes occurs and control the transfer and storage of water and chemical elements. This is the place where life-sustaining resources are, where nutrients are being released from the rocks. Because it is the place where we are living, this is a fragile zone, a critical zone as a perturbed natural ecosystem. Water resources in hard-rocks commonly involve different hydrogeological compartments such as overlying sediments, weathered rock, the weathered-fissured zone, and fractured bedrock. Streams, lakes and wetlands that drain such environments can drain groundwater, recharge groundwater, or do both. Groundwater resources in many countries are increasingly threatened by growing demand, wasteful use, and contamination. Surface water and shallow groundwater are particularly vulnerable to pollution, while deeper resources are more protected from contamination. Here, we first report on Sr isotope data as well as major ions, from shallow and deep groundwater in several granite and schist areas over France with intensive agriculture covering large parts of these catchments. In three granite and Brioverian 'schist' areas of the Armorican Massif, the range in Sr contents in groundwater from different catchments agrees with previous work on groundwater sampled from granites in France. The Sr content is well correlated with Mg and both are partly related to agricultural practices and water rock interaction. The relationship between Sr- isotope and Mg/Sr ratios allow defining the different end-members, mainly rain, agricultural practice and water-rock interaction. The data from the Armorican Massif and other surface and groundwater for catchment draining silicate bedrocks (300-450Ma) like the Hérault, Seine, Moselle, Garonne, Morvan, Margeride, Cantal, Pyrénées and Vosges are scattered between at least three geochemical signatures. These include fertilizer and

  19. Role of groundwater oxidation potential and radiolysis on waste glass performance in crystalline repository environments

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Bibler, N.E.

    1986-01-01

    Laboratory experiments have shown that groundwater conditions in a granite repository will be as reducing as those in a basalt repository. Chemical analysis of the reduced groundwaters confirmed that the Fe 2+ /Fe 3+ couple controls the oxidation potential (Eh). The reducing groundwater conditions were found to decrease the time-dependent release of soluble elements (Li and B) from the waste glass. However, due to the lower solubility of multivalent elements released from the glass when the groundwaters are reducing, these elements have significantly lower concentrations in the leachates. Gamma radiolysis reduced the oxidation potential of both granitic and basaltic groundwater in the absence of both waste glass and oxygen. This occurred in tests at atmospheric pressure where H 2 could have escaped from the solution. The mechanism for this decrease in Eh is under investigation but appears related to the reactive amorphous precipitate in both groundwaters. The results of these tests suggest that radiolysis may not cause the groundwaters to become oxidizing in a crystalline repository when abundant Fe 2+ species are present

  20. Recharge and Lateral Groundwater Flow Boundary Conditions for the Saturated Zone Site-Scale Flow and Transport Model

    Energy Technology Data Exchange (ETDEWEB)

    B. Arnold; T. Corbet

    2001-12-18

    The purpose of the flow boundary conditions analysis is to provide specified-flux boundary conditions for the saturated zone (SZ) site-scale flow and transport model. This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the SZ site-scale model domain, both as recharge at the upper (water table) boundary and as underflow at the lateral boundaries. The objective is to provide consistency at the boundaries between the SZ site-scale flow model and other groundwater flow models. The scope of this analysis includes extraction of the volumetric groundwater flow rates simulated by the SZ regional-scale flow model to occur at the lateral boundaries of the SZ site-scale flow model and the internal qualification of the regional-scale model for use in this analysis model report (AMR). In addition, the scope includes compilation of information on the recharge boundary condition taken from three sources: (1) distributed recharge as taken from the SZ regional-scale flow model, (2) recharge below the area of the unsaturated zone (UZ) site-scale flow model, and (3) focused recharge along the Fortymile Wash channel.

  1. Aquifer recharge with stormwater runoff in urban areas: Influence of vadose zone thickness on nutrient and bacterial transfers from the surface of infiltration basins to groundwater.

    Science.gov (United States)

    Voisin, Jérémy; Cournoyer, Benoit; Vienney, Antonin; Mermillod-Blondin, Florian

    2018-05-16

    Stormwater infiltration systems (SIS) have been built in urban areas to reduce the environmental impacts of stormwater runoff. Infiltration basins allow the transfer of stormwater runoff to aquifers but their abilities to retain contaminants depend on vadose zone properties. This study assessed the influence of vadose zone thickness (VZT) on the transfer of inorganic nutrients (PO 4 3- , NO 3 - , NH 4 + ), dissolved organic carbon (total -DOC- and biodegradable -BDOC-) and bacteria. A field experiment was conducted on three SIS with a thin vadose zone (zone (>10 m). Water samples were collected at three times during a rainy period of 10 days in each infiltration basin (stormwater runoff), in the aquifer impacted by infiltration (impacted groundwater) and in the same aquifer but upstream of the infiltration area (non-impacted groundwater). Inorganic nutrients, organic matter, and dissolved oxygen (DO) were measured on all water samples. Bacterial community structures were investigated on water samples through a next-generation sequencing (NGS) scheme of 16S rRNA gene amplicons (V5-V6). The concentrations of DO and phosphate measured in SIS-impacted groundwaters were significantly influenced by VZT due to distinct biogeochemical processes occurring in the vadose zone. DOC and BDOC were efficiently retained in the vadose zone, regardless of its thickness. Bacterial transfers to the aquifer were overall low, but data obtained on day 10 indicated a significant bacterial transfer in SIS with a thin vadose zone. Water transit time and water saturation of the vadose zone were found important parameters for bacterial transfers. Most bacterial taxa (>60%) from impacted groundwaters were not detected in stormwater runoff and in non-impacted groundwaters, indicating that groundwater bacterial communities were significantly modified by processes associated with infiltration (remobilization of bacteria from vadose zone and/or species sorting). Copyright © 2018 Elsevier B

  2. Contrasting patterns of groundwater evapotranspiration in grass and tree dominated riparian zones of a temperate agricultural catchment

    Science.gov (United States)

    Satchithanantham, Sanjayan; Wilson, Henry F.; Glenn, Aaron J.

    2017-06-01

    Consumptive use of shallow groundwater by phreatophytic vegetation is a significant part of the water budget in many regions, particularly in riparian areas. The influence of vegetation type on groundwater level fluctuations and evapotranspiration has rarely been quantified for contrasting plant communities concurrently although it has implications for downstream water yield and quality. Hourly groundwater evapotranspiration (ETG) rates were estimated for grass and tree riparian vegetation in southwestern Manitoba, Canada using two modified White methods. Groundwater table depth was monitored in four 21 m transects of five 3 m deep monitoring wells in the riparian zone of a stream reach including tree (Acer negundo; boxelder) and grass (Bromus inermis; smooth brome) dominated segments. The average depths to the groundwater table from the surface were 1.4 m and 1 m for the tree and grass segments, respectively, over the two-year study. During rain free periods of the growing season ETG was estimated for a total of 70 days in 2014 and 79 days in 2015 when diurnal fluctuations were present in groundwater level. Diurnal groundwater level fluctuations were observed during dry periods under both segments, however, ETG was significantly higher (p < 0.001) under trees compared to grass cover in 2014 (a wet year with 72% higher than normal growing season precipitation) and 2015 (a drier year with 15% higher than normal growing season precipitation). The two methods used to estimate ETG produced similar daily and seasonal values for the two segments. In 2014, total ETG was approximately 50% (148 mm) and 100% (282-285 mm) of reference evapotranspiration (ETref, 281 mm) for the grass and tree segments, respectively. In 2015, total ETG was approximately 40% (106-127 mm) and 120% (369-374 mm) of ETref (307 mm) for the grass and tree segments, respectively. Results from the study show the tree dominated portions of the stream reach consumed approximately 2.4 ML ha-1 yr-1 more

  3. Groundwater resource exploration in Salem district, Tamil Nadu ...

    Indian Academy of Sciences (India)

    Hence, proper assessment of groundwater potential and management practices are ..... Total. 8.33 3.67 5.58 12.50 11.50 17.00 5.83. Table 3. Relative weight matrix – thematic layers. ...... potential zones and zones of groundwater quality suit-.

  4. Depth Stratification Leads to Distinct Zones of Manganese and Arsenic Contaminated Groundwater.

    Science.gov (United States)

    Ying, Samantha C; Schaefer, Michael V; Cock-Esteb, Alicea; Li, Jun; Fendorf, Scott

    2017-08-15

    Providing access to safe drinking water is a global challenge, for which groundwater is increasingly being used throughout the world. However, geogenic contaminants limit the suitability of groundwater for domestic purposes over large geographic areas across most continents. Geogenic contaminants in groundwater are often evaluated individually, but here we demonstrate the need to evaluate multiple contaminants to ensure that groundwater is safe for human consumption and agricultural usage. We compiled groundwater chemical data from three aquifer regions across the world that have been reported to have widespread As and Mn contamination including the Glacial Aquifer in the U.S., the Ganges-Brahmaputra-Mehta Basin within Bangladesh, and the Mekong Delta in Cambodia, along with newly sampled wells in the Yangtze River Basin of China. The proportion of contaminated wells increase by up to 40% in some cases when both As and Mn contaminants are considered. Wilcoxon rank-sum analysis indicates that Mn contamination consistently occurs at significantly shallower depths than As contaminated wells in all regions. Arsenic concentrations in groundwater are well predicted by redox indicators (Eh and dissolved oxygen) whereas Mn shows no significant relationship with either parameter. These findings illustrate that the number of safe wells may be drastically overestimated in some regions when Mn contamination is not taken into account and that depth may be used as a distinguishing variable in efforts to predict the presence of groundwater contaminants regionally.

  5. Ground-water geology of the coastal zone, Long Beach-Santa Ana area, California

    Science.gov (United States)

    Poland, J.F.; Piper, A.M.

    1956-01-01

    This paper is the first chapter of a comprehensive report on the ground-water features in the southern part of the coastal plain in Los Angeles and Orange Counties, Calif., with special reference to the effectiveness of the so-called coastal barrier--the Newport-Inglewood structural zone--in restraining landwar,-1 movement of saline water. The coastal plain in Los Angeles and Orange Counties, which covers some 775 square miles, sustains a large urban and rural population, diverse industries, and intensive agricultural developments. The aggregate ground-water withdrawal in 1945 was about 400,000 acre-feet a year, an average of about 360 million gallons a day. The dominant land-form elements are a central lowland plain with tongues extending to the coast, bordering highlands and foothills, and a succession of low hills and mesas aligned northwestward along the coastal edge of the central low- land plain. These low hills and mesas are the land-surface expression of geologic structure in the Newport-Inglewood zone. The highland areas that border the inland edge of the coastal plain are of moderate altitude and relief; most of the ridge crests range from 1,400 to 2,500 feet in altitude, but Santiago Peak in the Santa Ana Mountains attains a height of 5,680 feet above sea level. From these highlands the land surface descends across foothills and aggraded alluvial aprons to the central lowland, Downey Plain, here defined as the surface formed by alluvial aggradation during the post-Pleistocene time of rising base level. The Newport-Inglewood belt of hills and plains (mesas) has a maximum relief of some 500 feet but is widely underlain at a depth of about 30 feet by a surface of marine plantation. As initially formed in late Pleistocene time that surface was largely a featureless plain. Thus the present land-surface forms within the Newport-Inglewood belt measure the earth deformation that has occurred there since late Pleistocene time and so are pertinent with respect to

  6. Vertical Electrical Sounding to delineate the potential Aquifer zones ...

    Indian Academy of Sciences (India)

    48

    CSIR-National Geophysical Research Institute, Groundwater Building, Uppal Road, ... techniques for groundwater prospecting was used in the Capital City, Niamey of Niger. ... Analysis of the result showed a good correlation between the ..... Fitterman D V, Meekes J A C, and Ritsema I L, 1988, Equivalence behavior of three ...

  7. Actively heated high-resolution fiber-optic-distributed temperature sensing to quantify streambed flow dynamics in zones of strong groundwater upwelling

    Science.gov (United States)

    Briggs, Martin A.; Buckley, Sean F.; Bagtzoglou, Amvrossios C.; Werkema, Dale D.; Lane, John W.

    2016-01-01

    Zones of strong groundwater upwelling to streams enhance thermal stability and moderate thermal extremes, which is particularly important to aquatic ecosystems in a warming climate. Passive thermal tracer methods used to quantify vertical upwelling rates rely on downward conduction of surface temperature signals. However, moderate to high groundwater flux rates (>−1.5 m d−1) restrict downward propagation of diurnal temperature signals, and therefore the applicability of several passive thermal methods. Active streambed heating from within high-resolution fiber-optic temperature sensors (A-HRTS) has the potential to define multidimensional fluid-flux patterns below the extinction depth of surface thermal signals, allowing better quantification and separation of local and regional groundwater discharge. To demonstrate this concept, nine A-HRTS were emplaced vertically into the streambed in a grid with ∼0.40 m lateral spacing at a stream with strong upward vertical flux in Mashpee, Massachusetts, USA. Long-term (8–9 h) heating events were performed to confirm the dominance of vertical flow to the 0.6 m depth, well below the extinction of ambient diurnal signals. To quantify vertical flux, short-term heating events (28 min) were performed at each A-HRTS, and heat-pulse decay over vertical profiles was numerically modeled in radial two dimension (2-D) using SUTRA. Modeled flux values are similar to those obtained with seepage meters, Darcy methods, and analytical modeling of shallow diurnal signals. We also observed repeatable differential heating patterns along the length of vertically oriented sensors that may indicate sediment layering and hyporheic exchange superimposed on regional groundwater discharge.

  8. 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

  9. Integration of Remote Sensing and other public GIS data source to identify suitable zones for groundwater exploitation by manual drilling

    Science.gov (United States)

    Fussi, Fabio; Fava, Francesco; Di Mauro, Biagio; Bonomi, Tullia; Fumagalli, Letizia; DI Leo, Margherita; Hamidou Kane, Cheik; Faye, Gayane; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto

    2015-04-01

    digital elevation models available (ASTER GDEM and SRTM). These variables have been combined using multivariate statistical methods (e.g. regression and classification trees) in order to study their relationship with hydrogeological parameters of shallow layers (namely thickness of porous aquifer, hydraulic conductivity and depth of water table) and estimate the suitability for manual drilling. Direct hydrogeological data in selected points obtained from semiautomatic analysis of stratigraphic borehole logs have been used in the definition and validation of the model. The results obtained demonstrate the potential of the proposed methodological approach to improve the estimation of manual drilling suitability using public data, widely available worldwide. Therefore, it has considerable potential to be replicated in other countries with limited costs. Furthermore, the maps of suitable zones for manual drilling produced in this research can help the promotion of this technique in Senegal and Guinea by different national and international organizations involved in water supply programs. This research is part of a larger project financed by NERC (National Environment Research Council, UK) in the framework of the program UPGRO (Unlocking the Potential of Groundwater for the Poors), with the collaboration of different partners from Italy, Senegal and Guinea.

  10. Conceptual Models for Migration of Key Groundwater Contaminants Through the Vadose Zone and Into the Upper Unconfined Aquifer Below the B-Complex

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey; Bjornstad, Bruce N.; Keller, Jason M.; Thorne, Paul D.; Lanigan, David C.; Christensen, J. N.; Thomas, Gregory S.

    2010-07-01

    The B-Complex contains 3 major crib and trench disposal sites and 3 SST farms that have released nearly 346 mega-liters of waste liquids containing the following high groundwater risk drivers: ~14,000 kg of CN, 29,000 kg of Cr, 12,000 kg of U and 145 Ci of Tc-99. After a thorough review of available vadose zone sediment and pore water, groundwater plume, field gamma logging, field electrical resistivity studies, we developed conceptual models for which facilities have been the significant sources of the contaminants in the groundwater and estimated the masses of these contaminants remaining in the vadose zone and currently present in the groundwater in comparison to the totals released. This allowed us to make mass balance calculations on how consistent our knowledge is on the current deep vadose zone and groundwater distribution of contaminants. Strengths and weaknesses of the conceptual models are discussed as well as implications on future groundwater and deep vadose zone remediation alternatives. Our hypothesized conceptual models attribute the source of all of the cyanide and most of the Tc-99 currently in the groundwater to the BY cribs. The source of the uranium is the BX-102 tank overfill event and the source of most of the chromium is the B-7-A&B and B-8 cribs. Our mass balance estimates suggest that there are much larger masses of U, CN, and Tc remaining in the deep vadose zone within ~20 ft of the water table than is currently in the groundwater plumes below the B-Complex. This hypothesis needs to be carefully considered before future remediation efforts are chosen. The masses of these groundwater risk drivers in the the groundwater plumes have been increasing over the last decade and the groundwater plumes are migrating to the northwest towards the Gable Gap. The groundwater flow rate appears to flucuate in response to seasonal changes in hydraulic gradient. The flux of contaminants out of the deep vadose zone from the three proposed sources also

  11. Application of a hybrid multiscale approach to simulate hydrologic and biogeochemical processes in the river-groundwater interaction zone.

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, Glenn Edward; Yang, Xiaofan; Song, Xuehang; Song, Hyun-Seob; Hou, Zhangshuan; Chen, Xingyuan; Liu, Yuanyuan; Scheibe, Tim

    2017-03-01

    The groundwater-surface water interaction zone (GSIZ) plays an important role in riverine and watershed ecosystems as the exchange of waters of variable composition and temperature (hydrologic exchange flows) stimulate microbial activity and associated biogeochemical reactions. Variable temporal and spatial scales of hydrologic exchange flows, heterogeneity of the subsurface environment, and complexity of biogeochemical reaction networks in the GSIZ present challenges to incorporation of fundamental process representations and model parameterization across a range of spatial scales (e.g. from pore-scale to field scale). This paper presents a novel hybrid multiscale simulation approach that couples hydrologic-biogeochemical (HBGC) processes between two distinct length scales of interest.

  12. Using a binary logistic regression method and GIS for evaluating and mapping the groundwater spring potential in the Sultan Mountains (Aksehir, Turkey)

    Science.gov (United States)

    Ozdemir, Adnan

    2011-07-01

    SummaryThe purpose of this study is to produce a groundwater spring potential map of the Sultan Mountains in central Turkey, based on a logistic regression method within a Geographic Information System (GIS) environment. Using field surveys, the locations of the springs (440 springs) were determined in the study area. In this study, 17 spring-related factors were used in the analysis: geology, relative permeability, land use/land cover, precipitation, elevation, slope, aspect, total curvature, plan curvature, profile curvature, wetness index, stream power index, sediment transport capacity index, distance to drainage, distance to fault, drainage density, and fault density map. The coefficients of the predictor variables were estimated using binary logistic regression analysis and were used to calculate the groundwater spring potential for the entire study area. The accuracy of the final spring potential map was evaluated based on the observed springs. The accuracy of the model was evaluated by calculating the relative operating characteristics. The area value of the relative operating characteristic curve model was found to be 0.82. These results indicate that the model is a good estimator of the spring potential in the study area. The spring potential map shows that the areas of very low, low, moderate and high groundwater spring potential classes are 105.586 km 2 (28.99%), 74.271 km 2 (19.906%), 101.203 km 2 (27.14%), and 90.05 km 2 (24.671%), respectively. The interpretations of the potential map showed that stream power index, relative permeability of lithologies, geology, elevation, aspect, wetness index, plan curvature, and drainage density play major roles in spring occurrence and distribution in the Sultan Mountains. The logistic regression approach has not yet been used to delineate groundwater potential zones. In this study, the logistic regression method was used to locate potential zones for groundwater springs in the Sultan Mountains. The evolved model

  13. Potential impact of climate change on groundwater resources in the Central Huai Luang Basin, Northeast Thailand.

    Science.gov (United States)

    Pholkern, Kewaree; Saraphirom, Phayom; Srisuk, Kriengsak

    2018-08-15

    The Central Huai Luang Basin is one of the important rice producing areas of Udon Thani Province in Northeastern Thailand. The basin is underlain by the rock salt layers of the Maha Sarakham Formation and is the source of saline groundwater and soil salinity. The regional and local groundwater flow systems are the major mechanisms responsible for spreading saline groundwater and saline soils in this basin. Climate change may have an impact on groundwater recharge, on water table depth and the consequences of waterlogging, and on the distribution of soil salinity in this basin. Six future climate conditions from the SEACAM and CanESM2 models were downscaled to investigate the potential impact of future climate conditions on groundwater quantity and quality in this basin. The potential impact was investigated by using a set of numerical models, namely HELP3 and SEAWAT, to estimate the groundwater recharge and flow and the salt transport of groundwater simulation, respectively. The results revealed that within next 30years (2045), the future average annual temperature is projected to increase by 3.1°C and 2.2°C under SEACAM and CanESM2 models, respectively, while the future precipitation is projected to decrease by 20.85% under SEACAM and increase by 18.35% under the CanESM2. Groundwater recharge is projected to increase under the CanESM2 model and to slightly decrease under the SEACAM model. Moreover, for all future climate conditions, the depths of the groundwater water table are projected to continuously increase. The results showed the impact of climate change on salinity distribution for both the deep and shallow groundwater systems. The salinity distribution areas are projected to increase by about 8.08% and 56.92% in the deep and shallow groundwater systems, respectively. The waterlogging areas are also projected to expand by about 63.65% from the baseline period. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Biostimulation of anaerobic BTEX biodegradation under fermentative methanogenic conditions at source-zone groundwater contaminated with a biodiesel blend (B20).

    Science.gov (United States)

    Ramos, Débora Toledo; da Silva, Márcio Luis Busi; Chiaranda, Helen Simone; Alvarez, Pedro J J; Corseuil, Henry Xavier

    2013-06-01

    Field experiments were conducted to assess the potential for anaerobic biostimulation to enhance BTEX biodegradation under fermentative methanogenic conditions in groundwater impacted by a biodiesel blend (B20, consisting of 20 % v/v biodiesel and 80 % v/v diesel). B20 (100 L) was released at each of two plots through an area of 1 m(2) that was excavated down to the water table, 1.6 m below ground surface. One release was biostimulated with ammonium acetate, which was added weekly through injection wells near the source zone over 15 months. The other release was not biostimulated and served as a baseline control simulating natural attenuation. Ammonium acetate addition stimulated the development of strongly anaerobic conditions, as indicated by near-saturation methane concentrations. BTEX removal began within 8 months in the biostimulated source zone, but not in the natural attenuation control, where BTEX concentrations were still increasing (due to source dissolution) 2 years after the release. Phylogenetic analysis using quantitative PCR indicated an increase in concentration and relative abundance of Archaea (Crenarchaeota and Euryarchaeota), Geobacteraceae (Geobacter and Pelobacter spp.) and sulfate-reducing bacteria (Desulfovibrio, Desulfomicrobium, Desulfuromusa, and Desulfuromonas) in the biostimulated plot relative to the control. Apparently, biostimulation fortuitously enhanced the growth of putative anaerobic BTEX degraders and associated commensal microorganisms that consume acetate and H2, and enhance the thermodynamic feasibility of BTEX fermentation. This is the first field study to suggest that anaerobic-methanogenic biostimulation could enhance source zone bioremediation of groundwater aquifers impacted by biodiesel blends.

  15. Geological study for identifying potential aquifer zone in Pakes and Bandung Villages, Konang District, Bangkalan Region

    International Nuclear Information System (INIS)

    I Gde Sukadana

    2010-01-01

    Konang District has a problem on fresh water supply particularly in dry season. Two villages in the district, namely Pakes and Konang, are densely populated areas having agriculture activities, so available of sufficient fresh water is necessary. A fresh water source that can be developed in this area is deep groundwater source from potential aquifers. A geological study has been conducted to identify potential aquifer based on lithological aspect and geological structure. According to the regional stratigraphy. the study area consists of Tawun Formation and Ngrayong Formation. They compose of carbonaceous clay stone (the oldest rock unit), carbonaceous clay stone with sandy limestone intercalations, sandy limestone interbed with carbonaceous clay stone, tuff sandstone with clay stone intercalations, and reef limestone (the youngest) respectively. Strike and dip positions of the rocks layers are N110°E/22° - N150°E/26°, located on the south anticline axis with wavy plan to gentle slope of hilly morphology. Among the rock unit, only sandy limestone has fine sand with sub angular in shape and open pack. Qualitatively. this rock has good porosity and permeability and is enables to save and to flow subsurface water. Thus. the sandy limestone is considered as a potential zone for fresh water resources. Whereas, carbonaceous clay stone with clay grain size has low porosity and permeability, so it is potential as a cap rock. (author)

  16. Assessing groundwater depletion and dynamics using GRACE and InSAR: Potential and limitations

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Galloway, Devin L.; Longuevergne, Laurent; Rivera, Alfonso

    2016-01-01

    In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km2). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

  17. Simulation of groundwater flow pathlines and freshwater/saltwater transition zone movement, Manhasset Neck, Nassau County, New York

    Science.gov (United States)

    Misut, Paul; Aphale, Omkar

    2014-01-01

    A density-dependent groundwater flow and solute transport model of Manhasset Neck, Long Island, New York, was used to analyze (1) the effects of seasonal stress on the position of the freshwater/saltwater transition zone and (2) groundwater flowpaths. The following were used in the simulation: 182 transient stress periods, representing the historical record from 1920 to 2011, and 44 transient stress periods, representing future hypothetical conditions from 2011 to 2030. Simulated water-level and salinity (chloride concentration) values are compared with values from a previously developed two-stress-period (1905–1944 and 1945–2005) model. The 182-stress-period model produced salinity (chloride concentration) values that more accurately matched the observed salinity (chloride concentration) values in response to hydrologic stress than did the two-stress-period model, and salinity ranged from zero to about 3 parts per thousand (equivalent to zero to 1,660 milligrams per liter chloride). The 182-stress-period model produced improved calibration statistics of water-level measurements made throughout the study area than did the two-stress-period model, reducing the Lloyd aquifer root mean square error from 7.0 to 5.2 feet. Decreasing horizontal and vertical hydraulic conductivities (fixed anisotropy ratio) of the Lloyd and North Shore aquifers by 20 percent resulted in nearly doubling the simulated salinity(chloride concentration) increase at Port Washington observation well N12508. Groundwater flowpath analysis was completed for 24 production wells to delineate water source areas. The freshwater/saltwater transition zone moved toward and(or) away from wells during future hypothetical scenarios.

  18. Geo - hydrological investigations and impact of water harvesting structures on groundwater potential in Anantapur District, Andhra Pradesh, India.

    Science.gov (United States)

    Suryanarayana, K V; Krishnaiah, S; Khokalay, Murthy Rao V

    2010-10-01

    In this paper, the data pertaining to the rainfall, its departure from normal, moving mean rainfall, depth of water levels in pre-monsoon and post-monsoon seasons, groundwater availability, groundwater utilization and impact of storage of water in large water bodies are analyzed graphically. The results indicate that the groundwater is over exploited in many places in Anantapur District (India). The groundwater levels found fluctuating, when compared the observations in pre-monsoon and post-monsoon seasons. Hence, it is concluded that the construction of water harvesting structures at suitable locations will have a definite impact on the groundwater potential in Anantapur District.

  19. Groundwater and quaternary geological studies of potential peat production areas - useful tool for sustainable peat production

    Energy Technology Data Exchange (ETDEWEB)

    Valpola, S.E.; Paalijaervi, M. (Geological Survey of Finland, Kokkola (Finland)), Email: samu.valpola@gtk.fi, Email: miikka.paalijarvi@gtk.fi

    2009-07-01

    Potential peat production areas in Finland are often situated in vicinity of eskers or other quaternary (glaciofluvial) formations. Frequently these formations are also important groundwater resources and it is essential for sustainable peat production to assure that these resources will not be endangered. The Geological Survey of Finland (GTK) has concluded several quaternary geological studies on potential peat production areas, which are connected to locally important groundwater areas. These studies have been made using mainly ground penetrating radar (GPR) and light drilling equipment. The main objective of these studies has been to establish the local groundwater flow directions and the quality and extent of quaternary deposits. The increasing need of peat production areas has created an evident demand of cost-effective and fast research methods which can be used for providing reliable information for planning of new production areas. (orig.)

  20. An approach to delineate groundwater recharge potential sites in Ambalantota, Sri Lanka using GIS techniques

    Directory of Open Access Journals (Sweden)

    I.P. Senanayake

    2016-01-01

    Full Text Available The demand for fresh water in Hambantota District, Sri Lanka is rapidly increasing with the enormous amount of ongoing development projects in the region. Nevertheless, the district experiences periodic water stress conditions due to seasonal precipitation patterns and scarcity of surface water resources. Therefore, management of available groundwater resources is critical, to fulfil potable water requirements in the area. However, exploitation of groundwater should be carried out together with artificial recharging in order to maintain the long term sustainability of water resources. In this study, a GIS approach was used to delineate potential artificial recharge sites in Ambalantota area within Hambantota. Influential thematic layers such as rainfall, lineament, slope, drainage, land use/land cover, lithology, geomorphology and soil characteristics were integrated by using a weighted linear combination method. Results of the study reveal high to moderate groundwater recharge potential in approximately 49% of Ambalantota area.

  1. Analysis of the functional gene structure and metabolic potential of microbial community in high arsenic groundwater.

    Science.gov (United States)

    Li, Ping; Jiang, Zhou; Wang, Yanhong; Deng, Ye; Van Nostrand, Joy D; Yuan, Tong; Liu, Han; Wei, Dazhun; Zhou, Jizhong

    2017-10-15

    Microbial functional potential in high arsenic (As) groundwater ecosystems remains largely unknown. In this study, the microbial community functional composition of nineteen groundwater samples was investigated using a functional gene array (GeoChip 5.0). Samples were divided into low and high As groups based on the clustering analysis of geochemical parameters and microbial functional structures. The results showed that As related genes (arsC, arrA), sulfate related genes (dsrA and dsrB), nitrogen cycling related genes (ureC, amoA, and hzo) and methanogen genes (mcrA, hdrB) in groundwater samples were correlated with As, SO 4 2- , NH 4 + or CH 4 concentrations, respectively. Canonical correspondence analysis (CCA) results indicated that some geochemical parameters including As, total organic content, SO 4 2- , NH 4 + , oxidation-reduction potential (ORP) and pH were important factors shaping the functional microbial community structures. Alkaline and reducing conditions with relatively low SO 4 2- , ORP, and high NH 4 + , as well as SO 4 2- and Fe reduction and ammonification involved in microbially-mediated geochemical processes could be associated with As enrichment in groundwater. This study provides an overall picture of functional microbial communities in high As groundwater aquifers, and also provides insights into the critical role of microorganisms in As biogeochemical cycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Submarine groundwater discharge and nutrient addition to the coastal zone of the Godavari estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rengarajan, R.; Sarma, V.V.S.S.

    .8 d during November 2011. Knowing the water age, the distribution of radium in the estuary, and the radium isotopic composition of groundwater enabled us to calculate SGD fluxes to the estuary. These fluxes (in units of 106 m3 d...

  3. Scoping studies on the effect of quaternary climate change on the hydrogeology in the Sellafield potential repository zone

    Energy Technology Data Exchange (ETDEWEB)

    Heathcote, J.A. [Entec UK Ltd., Shrewsbury (United Kingdom)

    1997-04-01

    The present investigations in the vicinity of the Sellafield potential repository zone have provided data on groundwater pressure and salinity to a depth of some 2000 m, for a section extending from the hills to the east of the zone, to the coast. As part of the process of demonstrating the suitability of the site for a deep repository, work has been undertaken to reconcile these observations of pressure and salinity with an understanding of the hydrogeology of the site. It is considered possible that the long glacial history of the site may in part be responsible for present observations. This work documents some preliminary studies to determine the possible magnitude of such glacial effects. 4 refs, 2 figs.

  4. Scoping studies on the effect of quaternary climate change on the hydrogeology in the Sellafield potential repository zone

    International Nuclear Information System (INIS)

    Heathcote, J.A.

    1997-01-01

    The present investigations in the vicinity of the Sellafield potential repository zone have provided data on groundwater pressure and salinity to a depth of some 2000 m, for a section extending from the hills to the east of the zone, to the coast. As part of the process of demonstrating the suitability of the site for a deep repository, work has been undertaken to reconcile these observations of pressure and salinity with an understanding of the hydrogeology of the site. It is considered possible that the long glacial history of the site may in part be responsible for present observations. This work documents some preliminary studies to determine the possible magnitude of such glacial effects. 4 refs, 2 figs

  5. Vinasse application to sugar cane fields. Effect on the unsaturated zone and groundwater at Valle del Cauca (Colombia).

    Science.gov (United States)

    Ortegón, Gloria Páez; Arboleda, Fernando Muñoz; Candela, Lucila; Tamoh, Karim; Valdes-Abellan, Javier

    2016-01-01

    Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416-599,400mgL(-1)) and elevated EC (14,350-64,099μScm(-1)). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water sample chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010-2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrient removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Remote sensing for assessing the zone of benefit where deep drains improve productivity of land affected by shallow saline groundwater.

    Science.gov (United States)

    Kobryn, H T; Lantzke, R; Bell, R; Admiraal, R

    2015-03-01

    The installation of deep drains is an engineering approach to remediate land salinised by the influence of shallow groundwater. It is a costly treatment and its economic viability is, in part, dependent on the lateral extent to which the drain increases biological productivity by lowering water tables and soil salinity (referred to as the drains' zone of benefit). Such zones may be determined by assessing the biological productivity response of adjacent vegetation over time. We tested a multi-temporal satellite remote sensing method to analyse temporal and spatial changes in vegetation condition surrounding deep drainage sites at five locations in the Western Australian wheatbelt affected by dryland salinity-Morawa, Pithara, Beacon, Narembeen and Dumbleyung. Vegetation condition as a surrogate for biological productivity was assessed by Normalised Difference Vegetation Index (NDVI) during the peak growing season. Analysis was at the site scale within a 1000 m buffer zone from the drains. There was clear evidence of NDVI increasing with elevation, slope and distance from the drain. After accounting for elevation, slope and distance from the drain, there was a significant increase in NDVI across the five locations after installation of deep drains. Changes in NDVI after drainage were broadly consistent with measured changes at each site in groundwater levels after installation of the deep drains. However, this study assessed the lateral extent of benefit for biological productivity and gave a measure of the area of benefit along the entire length of the drain. The method demonstrated the utility of spring NDVI images for rapid and relatively simple assessment of the change in site condition after implementation of drainage, but approaches for further improvement of the procedure were identified. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Concentrations and potential health hazards of organochlorine pesticides in (shallow) groundwater of Taihu Lake region, China.

    Science.gov (United States)

    Wu, Chunfa; Luo, Yongming; Gui, Tong; Huang, Yujuan

    2014-02-01

    A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water. © 2013.

  8. Iron cycling potentials of arsenic-contaminated groundwater in Bangladesh as revealed by enrichment cultivation.

    NARCIS (Netherlands)

    Hassan, Z.; Sultana, M.; Westerhoff, H.V.; Khan, S.I.; Roling, W.F.M.

    2015-01-01

    The activities of iron-oxidizing and reducing microorganisms impact the fate of arsenic in groundwater. Phylogenetic information cannot exclusively be used to infer the potential for iron oxidation or reduction in aquifers. Therefore, we complemented a previous cultivation-independent microbial

  9. Aerobic degradation potential of the herbicides mecoprop, dichlorprop and bentazone in groundwater from chalk aquifers

    DEFF Research Database (Denmark)

    Levi, Suzi; Hybel, Anne-Marie; Bjerg, Poul Løgstrup

    2011-01-01

    The aerobic degradation potential of mecoprop, dichlorprop and bentazone was studied at concentration of 1 μg/L in laboratory batch experiments with groundwater from chalk aquifers. Within the incubation period of 129 days, 14C-mecoprop concentration decreased to 60-80% in the microcosms with gro...

  10. Application of multi-criteria decision analysis in prediction of groundwater resources potential: A case of Oke-Ana, Ilesa Area Southwestern, Nigeria

    Directory of Open Access Journals (Sweden)

    A.A. Akinlalu

    2017-06-01

    Full Text Available Groundwater Potential of Oke-Ana area southwestern Nigeria have been evaluated using the integration of electrical resistivity method, remote sensing and geographic information systems. The effect of five hydrogeological indices, namely lineament density, drainage density, lithology, overburden thickness and aquifer layer resistivity on groundwater occurrence was established. Multi-criteria decision analysis technique was employed to assign weight to each of the index using the concept of analytical hierarchy process. The assigned weight was normalized and consistency ratio was established. In order to evaluate the groundwater potential of Oke-Ana, sixty-seven (67 vertical electrical sounding points were occupied. Ten curve types were delineated in the study area. The curve types vary from simple three layer A and H-type curves to the more complex four, five and six layer AA, HA, KH, QH, AKH, HKH, KHA and KHKH curves. Four subsurface geo-electric sequences of top soil, weathered layer, partially weathered/fractured basement and the fresh basement were delineated in the area. The analytical process assisted in classifying Oke-Ana into, low, medium and high groundwater potential zones. Validation of the model from well information and two aborted boreholes suggest 70% agreement.

  11. Groundwater exploration by self-potential method; Shizen den`iho ni yoru chikasui tansa

    Energy Technology Data Exchange (ETDEWEB)

    Onaru, I; Irie, S; Mizunaga, H; Ushijima, K [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1997-05-27

    This paper describes results measured from the field experiments and data analysis of the groundwater exploration by self-potential method. The field survey was conducted in the vicinity of spring water source in the suburbs of Fukuoka City. For the field experiments, potential differences from the standard potential electrode set at the distance about 200 m were measured at multi-points, simultaneously. For the laboratory experiments, assuming that the groundwater flows in a permeable layer, streaming potential change was observed against the changes of flow rate and electrical conductivity. Thus, the generation of streaming potential was investigated. For the experiment using specimens obtained at the spring water source, the potential changed to negative and was stabilized in around -80 mV after 15 minutes. Numerical simulation was conducted by means of the three-dimensional finite difference method using parameters obtained from the laboratory experiments. From these results, the groundwater flow image could be obtained. It was also confirmed that the self-potential observed in the spring water source area was caused by the streaming potential. 11 refs., 9 figs.

  12. Pollution potential of oil-contaminated soil on groundwater resources in Kuwait

    International Nuclear Information System (INIS)

    Literathy, P.; Quinn, M.; Al-Rashed, M.

    2003-01-01

    The only natural freshwater resource of Kuwait occurs as lenses floating on the saline groundwater in the northern part of the country, near to the oil fields. Rainwater is the only means of recharge of this limited groundwater resource. This groundwater is used as bottled drinking water and the fresh groundwater aquifer is considered as a strategic drinking water reserve for Kuwait. As a result of the 1991 Gulf War, the upper soil layer has been widely contaminated with crude oil and crude oil combustion products, which are potential pollutants likely affecting the groundwater resources. Significant efforts have been made to assess this pollution. These included: (a) a soil survey for assessing the soil contamination, and (b) leaching experiments to characterise the mobilization of the soil-associated pollutants. Fluorescence measurement techniques were used during field surveys as well as for laboratory testing. In addition, determination of the total extractable matter (TEM), total petroleum hydrocarbons (TPH), and GC/MS measurement of polyaromatic hydrocarbons (PAHs) were performed for the assessments. The laser induced fluorescence (LIF) measurement, having good correlation with the other laboratory measurements, was proved to provide necessary information for the assessment of the oil-contamination level in the desert soil. The subsequent leaching test with water demonstrated the mobilization of the fluorescing compounds (e.g. PAHs), and the alteration in the leaching characteristics of the contamination during the long term environmental weathering of the oil. (author)

  13. Seasonal Arsenic Accumulation in Stream Sediments at a Groundwater Discharge Zone

    DEFF Research Database (Denmark)

    MacKay, Allison A.; Gan, Ping; Yu, Ran

    2014-01-01

    Seasonal changes in arsenic and iron accumulation rates were examined in the sediments of a brook that receives groundwater discharges of arsenic and reduced iron. Clean glass bead columns were deployed in sediments for known periods over the annual hydrologic cycle to monitor changes in arsenic...... and iron concentrations in bead coatings. The highest accumulation rates occurred during the dry summer period (July-October) when groundwater discharges were likely greatest at the sample locations. The intermediate flow period (October-March), With higher surface water: levels, was associated with losses...... of arsenic and iron from bead column coatings at. depths below 2-6 cm. Batch incubations indicated iron releases from solids to be induced by biological reduction of iron (oxy)hydroxide solids. Congruent arsenic releases during incubation were limited by the high arsenic sorption capacity (0.536 mg...

  14. Vadose zone processes delay groundwater nitrate reduction response to BMP implementation as observed in paired cultivated vs. uncultivated potato rotation fields

    Science.gov (United States)

    Jiang, Y.; Nyiraneza, J.; Murray, B. J.; Chapman, S.; Malenica, A.; Parker, B.

    2017-12-01

    Nitrate leaching from crop production contributes to groundwater contamination and subsequent eutrophication of the receiving surface water. A study was conducted in a 7-ha potato-grain-forages rotation field in Prince Edward Island (PEI), Canada during 2011-2016 to link potato rotation practices and groundwater quality. The field consists of fine sandy loam soil and is underlain by 7-9 m of glacial till, which overlies the regional fractured ;red-bed; sandstone aquifer. The water table is generally located in overburden close to the bedrock interface. Field treatments included one field zone taken out of production in 2011 with the remaining zones kept under a conventional potato rotation. Agronomy data including crop tissue, soil, and tile-drain water quality were collected. Hydrogeology data including multilevel monitoring of groundwater nitrate and hydraulic head and data from rock coring for nitrate distribution in overburden and bedrock matrix were also collected. A significant amount of nitrate leached below the soil profile after potato plant kill (referred to as topkill) in 2011, most of it from fertilizer N. A high level of nitrate was also detected in the till vadose zone through coring in December 2012 and through multilevel groundwater sampling from January to May 2014 in both cultivated and uncultivated field zones. Groundwater nitrate concentrations increased for about 2.5 years after the overlying potato field was removed from production. Pressure-driven uniform flow processes dominate water and nitrate transport in the vadose zone, producing an apparently instant water table response but a delayed groundwater quality response to nitrate leaching events. These data suggest that the uniform flow dominated vadose zone in agricultural landscapes can cause the accumulation of a significant amount of nitrate originated from previous farming activities, and the long travel time of this legacy nitrate in the vadose zone can result in substantially delayed

  15. Delineating Groundwater Vulnerability and Protection Zone Mapping in Fractured Rock Masses: Focus on the DISCO Index

    Directory of Open Access Journals (Sweden)

    Helen Meerkhan

    2016-10-01

    Full Text Available Hard-rock catchments are considered to be source of valuable water resources for water supply to inhabitants and ecosystems. The present work aims to develop a groundwater vulnerability approach in the Caldas da Cavaca hydromineral system (Aguiar da Beira, Central Portugal in order to improve the hydrogeological conceptual site model. Different types of information were overlaid, generating several thematic maps to achieve an integrated framework of key sectors in the study site. Thus, a multi-technical approach was used, encompassing field and laboratory techniques, whereby different types of data were collected from fields such as geology, hydrogeology, applied geomorphology and geophysics and hydrogeomechanics, with the fundamental aim of applying the so-called DISCO index method. All of these techniques were successfully performed and an intrinsic groundwater vulnerability to contamination assessment, based on the multicriteria methodology of GOD-S, DRASTIC-Fm, SINTACS, SI and DISCO indexes, was delineated. Geographic Information Systems (GIS provided the basis on which to organize and integrate the databases and to produce all the thematic maps. This multi-technical approach highlights the importance of groundwater vulnerability to contamination mapping as a tool to support hydrogeological conceptualization, contributing to improving the decision-making process regarding water resources management and sustainability.

  16. Hydrogeophysical investigation of groundwater potential and aquifer vulnerability prediction in basement complex terrain - A case study from Akure, Southwestern Nigeria

    Science.gov (United States)

    Akinrinade, Opeyemi J.; Adesina, Rasheed B.

    2016-06-01

    This study provides a model for the prediction of groundwater potential and vulnerability of basement aquifers in parts of Akure, Southwestern Nigeria. Hydrogeophysical surveys involving very-low-frequency electromagnetic (VLF-EM) profiling and electrical resistivity (ER) sounding, as well as evaluation of hydraulic gradient using three-point method, were carried out. Ten VLF-EM reconnaissance survey traverses, with lengths ranging from 55 m to 75 m, at 10 m station separation, and 12 vertical electrical sounding (VES) stations were occupied. Two-dimensional map of the filtered real component reveals areas of high conductivity, indicative of linear features that can serve as a reservoir or conduit for fluid flow. Interpretation of the VES results delineates three to four geoelectric units. Two aquifer zones were identified, with resistivity values in the ranges of 20 Ωm to 310 Ωm and 100 Ωm to 3,000 Ω m, respectively. Transverse resistance, longitudinal conductance, coefficient of anisotropy and hydraulic gradient have values ranging from 318.2 Ωm2 to 1,041.8 Ωm2, 0.11 mhos to 0.39 mhos, 1.04 to 1.74 and 0.017 to 0.05, respectively. The results of this study identified two prospective borehole locations and the optimum position to site the proposed septic system, based on the aquifer's protective capacity and groundwater flow properties.

  17. Groundwater monitoring and modelling of the “Vector” site for near-surface radioactive waste disposal in the Chornobyl exclusion zone

    Directory of Open Access Journals (Sweden)

    D. Bugai

    2017-12-01

    Full Text Available Results of purposeful groundwater monitoring and modelling studies are presented, which were carried out in order to better understand groundwater flow patterns from the “Vector” site for near-surface radioactive waste disposal and storage in the Chornobyl exclusion zone towards river network. Both data of observations at local-scale monitoring well network at “Vector” site carried out in 2015 - 2016 and modelling analyses using the regional groundwater flow model of Chornobyl exclusion zone suggest that the groundwater discharge contour for water originating from “Vector” site is Sakhan River, which is the tributary to Pripyat River. The respective groundwater travel time is estimated at 210 - 340 years. The travel times in subsurface for 90Sr, 137Cs, and transuranium radionuclides (Pu isotopes, 241Am are estimated respectively at thousands, tenths of thousands, hundreds of thousands – million of years. These results, as well as presented data of analyses of lithological properties of the geological deposits of the unsaturated zone at “Vector” site, provide evidence for good protection of surface water resources from radioactivity sources (e.g., radioactive wastes to be disposed in the near-sursface facilities at “Vector” site.

  18. The influence of the unsaturated zone on the high fluoride contents in groundwater in the middle voltaian aquifers-the Gusghegu District, Northern Region

    International Nuclear Information System (INIS)

    Salifu, M.

    2012-01-01

    Elevated levels of fluoride have been reported to occur in some groundwater in the Gushegu district of the Northern region of Ghana leading to the closure of some boreholes in the area. Hydrochemical data from 21 water, soil and some rock samples were used to evaluate water quality, water types and to identify whether the unsaturated zone has influence on the elevated fluoride levels in groundwater as well as the processes that control fluoride level in the groundwater. Water samples were extracted from soil sample for flouride analysis using the cryogenic vacuum extraction set-up. Results of the water quality analysis showed that the groundwater in the study area were generally potable. A plot of Gibbs diagram revealed that rock weathering and rainfall were the major hydrogeochemical processes regulating the water chemistry of the study area. Two different water types were identified in the study area, namely: Na-HCO 3 - , which happened to be the major water type in the study area and Na-Ca-Mg-HCO 3 - water type. The fluoride concentration in the groundwater varied from 0.0 to 1.97 mg/L while that of the unsaturated zone ranged from 0.0 to 2.08 mg/L. The elevated fluoride levels in the groundwater strongly correlated with that of fluoride levels in the unsaturated zone (r 2 =0.76). Petrographic analysis of rock samples (siltstones) identified the minerals present to be muscovite, plagioclase feldspars, quartz, sericite and iron oxide. Other clay minerals such as montmorillonite, illite and chloride were identified. The elevated fluoride levels recorded in the groundwater may be due to leaching, as a result of the weathering and dissolution of muscovite, sericite as well as the presence of other clay minerals in the unsaturated zone. Application of phosphate fertilizers may also account for the the elevated fluoride concentrations recorded in the study area. Stable isotopic composition of the waters revealed that most of the groundwater were of meteoric origin

  19. Heterogeneity of groundwater storage properties in the critical zone of Irish metamorphic basement from geophysical surveys and petrographic analyses

    Science.gov (United States)

    Comte, Jean-Christophe; Cassidy, Rachel; Caulfield, John; Nitsche, Janka; Ofterdinger, Ulrich; Wilson, Christopher

    2016-04-01

    Weathered/fractured bedrock aquifers contain groundwater resources that are crucial in hard rock basement regions for rural water supply and maintaining river flow and ecosystem resilience. Groundwater storage in metamorphic rocks is subject to high spatial variations due to the large degree of heterogeneity in fracture occurrence and weathering patterns. Point measurements such as borehole testing are, in most cases, insufficient to characterise and quantify those storage variations because borehole sampling density is usually much lower than the scale of heterogeneities. A suite of geophysical and petrographic investigations was implemented in the weathered/fractured micaschist basement of Donegal, NW Ireland. Electrical Resistivity Tomography provided a high resolution 2D distribution of subsurface resistivities. Resistivity variations were transferred into storage properties (i.e. porosities) in the saturated critical zone of the aquifer through application of a petrophysical model derived from Archie's Law. The petrophysical model was calibrated using complementary borehole gamma logging and clay petrographic analysis at multi-depth well clusters distributed along a hillslope transect at the site. The resulting distribution of porosities shows large spatial variations along the studied transect. With depth, porosities rapidly decrease from about a few % in the uppermost, highly weathered basement to less than 0.5% in the deep unweathered basement, which is encountered at depths of between 10 and 50m below the ground surface. Along the hillslope, porosities decrease with distance from the river in the valley floor, ranging between 5% at the river to less than 1% at the top of the hill. Local traces of regional fault zones that intersect the transect are responsible for local increases in porosity in relation to deeper fracturing and weathering. Such degrees of spatial variation in porosity are expected to have a major impact on the modality of the response of

  20. Assessment of groundwater potentiality using geophysical techniques in Wadi Allaqi basin, Eastern Desert, Egypt - Case study

    Science.gov (United States)

    Helaly, Ahmad Sobhy

    2017-12-01

    Electrical resistivity surveying has been carried out for the determination of the thickness and resistivity of layered media in Wadi Allaqi, Eastern Desert, Egypt. That is widely used geophysical tool for the purpose of assessing the groundwater potential and siting the best locations for boreholes in the unconfined Nubian Sandstone aquifers within the study area. This has been done using thirteen 1D Vertical Electrical Sounding (VES) surveys. 1D-VES surveys provide only layered model structures for the subsurface and do not provide comprehensive information for interpreting the structure and extent of subsurface hydro-geological features. The integration of two-dimensional (2D) geophysical techniques for groundwater prospecting has been done to provide a more detailed identification for the subsurface hydro-geological features from which potential sites for successful borehole locations are recognized. In addition, five magnetic profiles were measured for basement depth determination, expected geological structures and thickness of sedimentary succession that could include some basins suitable for groundwater accumulation as groundwater aquifers.

  1. Dissipation of the herbicide oxyfluorfen in subtropical soils and its potential to contaminate groundwater.

    Science.gov (United States)

    Yen, Jui-Hung; Sheu, Wey-Shin; Wang, Yei-Shung

    2003-02-01

    The dissipation and mobility of the herbicide oxyfluorfen (2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether) in field soil of Taiwan were investigated in the laboratory with six tea garden soils. The dissipation coefficients of oxyfluorfen in soils of different moisture content (30%, 60%, and 90% of soil field capacity) and soil temperature (10 degrees C, 25 degrees C, and 40 degrees C) were studied. Results indicate that the half-life of oxyfluorfen ranged from 72 to 160 days for six tea garden soils. It was found that if the temperature is high, the dissipation rate is rapid, and there is almost no dissipation at 10 degrees C. Possible contamination of groundwater by the herbicide oxyfluorfen was assessed using the behavior assessment model and the groundwater pollution-potential (GWP) model. The results obtained after evaluating the residue and travel time using the GWP model illustrated that oxyfluorfen is not very mobile in soil and may not contaminate groundwater under normal conditions. But in the case of soil of extremely low organic carbon content and coarse texture, oxyfluorfen has the potential to contaminate groundwater less than 3m deep.

  2. Evaluation of radon occurrence in groundwater from 16 geologic units in Pennsylvania, 1986–2015, with application to potential radon exposure from groundwater and indoor air

    Science.gov (United States)

    Gross, Eliza L.

    2017-05-11

    Results from 1,041 groundwater samples collected during 1986‒2015 from 16 geologic units in Pennsylvania, associated with 25 or more groundwater samples with concentrations of radon-222, were evaluated in an effort to identify variations in radon-222 activities or concentrations and to classify potential radon-222 exposure from groundwater and indoor air. Radon-222 is hereafter referred to as “radon.” Radon concentrations in groundwater greater than or equal to the proposed U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) for public-water supply systems of 300 picocuries per liter (pCi/L) were present in about 87 percent of the water samples, whereas concentrations greater than or equal to the proposed alternative MCL (AMCL) for public water-supply systems of 4,000 pCi/L were present in 14 percent. The highest radon concentrations were measured in groundwater from the schists, gneisses, and quartzites of the Piedmont Physiographic Province.In this study, conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Health and the Pennsylvania Department of Environmental Protection, groundwater samples were aggregated among 16 geologic units in Pennsylvania to identify units with high median radon concentrations in groundwater. Graphical plots and statistical tests were used to determine variations in radon concentrations in groundwater and indoor air. Median radon concentrations in groundwater samples and median radon concentrations in indoor air samples within the 16 geologic units were classified according to proposed and recommended regulatory limits to explore potential radon exposure from groundwater and indoor air. All of the geologic units, except for the Allegheny (Pa) and Glenshaw (Pcg) Formations in the Appalachian Plateaus Physiographic Province, had median radon concentrations greater than the proposed EPA MCL of 300 pCi/L, and the Peters Creek Schist (Xpc), which is in the Piedmont

  3. An analysis of potential impacts to the groundwater monitoring networks in the Central Plateau. Revision 0

    International Nuclear Information System (INIS)

    1996-01-01

    This report presents the results of an evaluation of potential impacts to the four groundwater monitoring projects operating in the Central Plateau of the Hanford Site. It specifically fulfills Milestone M-15-81A of the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). Milestone M-15-81A specifies the evaluation of the potential impacts to the groundwater monitoring well systems in the Central Plateau caused by the following activities: reduction of liquids discharged to soil, proposed and operational liquid treatment facilities, and proposed pump-and-treat systems. For this report, an open-quotes impactclose quotes is defined as a restriction of the ability to draw samples from a well and/or a reduction of the ability of a monitoring well to meet its intended purpose (such as the detection of contaminant seepage from a facility). Approximately 20% (74 wells) of the groundwater monitoring wells potentially will experience sampling problems by the year 2005 due to the declining water table in the Central Plateau. Reduction of discharges to the B Pond complex and operation of the Treated Effluent Disposal System will directly cause four additional wells to potentially experience sampling problems. Approximately 90 monitoring wells (35 of which are Resource Conservation and Recovery Act of 1976 [RCRA] wells) will be potentially affected by the operation of pump-and-treat systems in the 200 West Area. Most of the impacts will be caused by local changes to groundwater flow directions that will potentially reduce the ability of the RCRA well network to monitor a limited number of RCRA facilities

  4. High Frequency Electromagnetic Impedance Imaging for Vadose Zone and Groundwater Characterization

    International Nuclear Information System (INIS)

    Newman, Greory A.; Alumbaugh, David L.; Hoversten, Michael; Nichols, Edward

    2003-01-01

    A geophysical experiment is described for characterizing the clastic dike systems, which are ubiquitous within the vadose zone at the Hanford Nuclear Reservation. because the dikes possess a significant electrical contrast from the insulating host medium, we have applied controlled source audio magnetotelluric (CSAMT) measurements to map their geometric extent and to further clarify if the dike complex acts as a conduit for contaminant transport within the vadose zone. Because of cost and weak natural field signal levels, we employed controlled field sourcing using the STRATGEM acquisition system. Use of artificial fields often goes with the assumption that the data required in the far-field of the transmitter

  5. Influences of Dam Operations in Groundwater-Surface Water Mixing Zones: Towards Multiscale Understanding

    Science.gov (United States)

    Stegen, J.; Scheibe, T. D.; Chen, X.; Huang, M.; Arntzen, E.; Garayburu-Caruso, V. A.; Graham, E.; Johnson, T. C.; Strickland, C. E.

    2017-12-01

    The installation and operation of dams have myriad influences on ecosystems, from direct effects on hydrographs to indirect effects on marine biogeochemistry and terrestrial food webs. With > 50000 existing and > 3700 planned large dams world-wide there is a pressing need for holistic understanding of dam impacts. Such understanding is likely to reveal unrecognized opportunities to modify dam operations towards beneficial outcomes. One of the most dramatic influences of daily dam operations is the creation of `artificial intertidal zones' that emerge from short-term increases and decreases in discharge due to hydroelectric power demands; known as hydropeaking. There is a long history of studying the influences of hydropeaking on macrofauna such as fish and invertebrates, but only recently has significant attention been paid to the hydrobiogeochemical effects of hydropeaking. Our aim here is to develop an integrated conceptual model of the hydrobiogeochemical influences of hydropeaking. To do so we reviewed available literature focusing on hydrologic and/or biogeochemical influences of hydropeaking. Results from these studies were collated into a single conceptual model that integrates key physical (e.g., sediment transport, hydromorphology) and biological (e.g., timescale of microbiome response) processes. This conceptual model highlights non-intuitive impacts of hydropeaking, the presence of critical thresholds, and strong interactions among processes. When examined individually these features suggest context dependency, but when viewed through an integrated conceptual model, common themes emerge. We will further discuss a critical next step, which is the local to regional to global evaluation of this conceptual model, to enable multiscale understanding. We specifically propose a global `hydropeaking network' of researchers using common methods, data standards, and analysis techniques to quantify the hydrobiogeochemical effects of hydropeaking across biomes. We

  6. Long term variations of chlorine-36 input signal to groundwater as recorded in deep unsaturated zones, south-east Australia

    International Nuclear Information System (INIS)

    Le Gal La Salle, C.; Herczeg, A.L.; Leaney, F.W.; Fifield, L.K.; Cresswell, R.G.; Kellet, J.

    1997-01-01

    The use of chlorine-36 is increasing in hydrology as its long half-life (3x10 5 a), allows useful long-term investigations into groundwater systems. Because chloride is very hydrophillic, the chlorine-36 signal should not be affected by geochemical processes in most aquatic systems. Nevertheless, over long periods of time, the chlorine-36 input to groundwater systems may vary due to factors such as: changes of production of chlorine-36 and/or changes of its distribution in the atmosphere. For instance the production of chlorine-36 might be governed by long-term terrestrial magnetic dipole strength variations as suggested for other radiogenic isotopes. Variations of the input signal of chlorine-36 should be recorded in pore waters of deep unsaturated zones. In this system, the time scale is approximated by the cumulative chloride content with depth assuming a constant input of chloride. Long-term records of chloride and chlorine-36 in two deep unsaturated-zone profiles, situated in the semi-arid Murray Basin in Australia, are presented. The two profiles record periods of approximately 20±1 to 27±2 ka and 100±5 to 220±10 ka respectively. The range of variation of the recorded time at each site is related to the estimated range of chloride deposition rate. The recharge rates are constant in both profiles with values approximating 0.4 and less than 0.1 mm.a -1 respectively. The linear relationship between chlorine-36 and stable chloride indicates that variations of chlorine-36 are governed by evapotranspiration, with a concentration factor of up to 2. Therefore the chlorine-36 is normalised to chloride to take account of the evapotranspiration process. In the soil profile at Kaniva, Western Victoria, 36 Cl/Cl'- ratio shows an increase of approximately 20% down profile. The second profile at Boree Plains, Wester, NSW, shows variations of 36 Cl/Cl'- ratio of 40% with a decreasing trend down profile. The input signal of chlorine-36/chloride is calculated by correction

  7. Redox zone II. Coupled modeling of groundwater flow, solute transport, chemical reactions and microbial processes in the Aespoe island

    Energy Technology Data Exchange (ETDEWEB)

    Samper, Javier; Molinero, Jorge; Changbing Yang; Guoxiang Zhang [Univ. Da Coruna (Spain)

    2003-12-01

    The Redox Zone Experiment was carried out at the Aespoe HRL in order to study the redox behaviour and the hydrochemistry of an isolated vertical fracture zone disturbed by the excavation of an access tunnel. Overall results and interpretation of the Redox Zone Project were reported by Banwart et al. Later, Banwart presented a summary of the hydrochemistry of the Redox Zone Experiment. Coupled groundwater flow and reactive transport models of this experiment were carried out by Molinero who proposed a revised conceptual model for the hydrogeology of the Redox Zone Experiment which could explain simultaneously measured drawdown and salinity data. The numerical model was found useful to understand the natural system. Several conclusions were drawn about the redox conditions of recharge waters, cation exchange capacity of the fracture zone and the role of mineral phases such as pyrite, calcite, hematite and goethite. This model could reproduce the measured trends of dissolved species, except for bicarbonate and sulphate which are affected by microbially-mediated processes. In order to explore the role of microbial processes, a coupled numerical model has been constructed which accounts for water flow, reactive transport and microbial processes. The results of this model is presented in this report. This model accounts for groundwater flow and reactive transport in a manner similar to that of Molinero and extends the preliminary microbial model of Zhang by accounting for microbially-driven organic matter fermentation and organic matter oxidation. This updated microbial model considers simultaneously the fermentation of particulate organic matter by yeast and the oxidation of dissolved organic matter, a product of fermentation. Dissolved organic matter is produced by yeast and serves also as a substrate for iron-reducing bacteria. Model results reproduce the observed increase in bicarbonate and sulfaphe concentration, thus adding additional evidence for the possibility

  8. Redox zone II. Coupled modeling of groundwater flow, solute transport, chemical reactions and microbial processes in the Aespoe island

    International Nuclear Information System (INIS)

    Samper, Javier; Molinero, Jorge; Changbing Yang; Guoxiang Zhang

    2003-12-01

    The Redox Zone Experiment was carried out at the Aespoe HRL in order to study the redox behaviour and the hydrochemistry of an isolated vertical fracture zone disturbed by the excavation of an access tunnel. Overall results and interpretation of the Redox Zone Project were reported by Banwart et al. Later, Banwart presented a summary of the hydrochemistry of the Redox Zone Experiment. Coupled groundwater flow and reactive transport models of this experiment were carried out by Molinero who proposed a revised conceptual model for the hydrogeology of the Redox Zone Experiment which could explain simultaneously measured drawdown and salinity data. The numerical model was found useful to understand the natural system. Several conclusions were drawn about the redox conditions of recharge waters, cation exchange capacity of the fracture zone and the role of mineral phases such as pyrite, calcite, hematite and goethite. This model could reproduce the measured trends of dissolved species, except for bicarbonate and sulphate which are affected by microbially-mediated processes. In order to explore the role of microbial processes, a coupled numerical model has been constructed which accounts for water flow, reactive transport and microbial processes. The results of this model is presented in this report. This model accounts for groundwater flow and reactive transport in a manner similar to that of Molinero and extends the preliminary microbial model of Zhang by accounting for microbially-driven organic matter fermentation and organic matter oxidation. This updated microbial model considers simultaneously the fermentation of particulate organic matter by yeast and the oxidation of dissolved organic matter, a product of fermentation. Dissolved organic matter is produced by yeast and serves also as a substrate for iron-reducing bacteria. Model results reproduce the observed increase in bicarbonate and sulfaphe concentration, thus adding additional evidence for the possibility

  9. Impact of radionuclide spatial variability on groundwater quality downstream from a shallow waste burial in the Chernobyl Exclusion Zone

    Science.gov (United States)

    Nguyen, H. L.; de Fouquet, C.; Courbet, C.; Simonucci, C. A.

    2016-12-01

    The effects of spatial variability of hydraulic parameters and initial groundwater plume localization on the possible extent of groundwater pollution plumes have already been broadly studied. However, only a few studies, such as Kjeldsen et al. (1995), take into account the effect of source term spatial variability. We explore this question with the 90Sr migration modeling from a shallow waste burial located in the Chernobyl Exclusion Zone to the underlying sand aquifer. Our work is based upon groundwater sampled once or twice a year since 1995 until 2015 from about 60 piezometers and more than 3,000 137Cs soil activity measurements. These measurements were taken in 1999 from one of the trenches dug after the explosion of the Chernobyl nuclear power plant, the so-called "T22 Trench", where radioactive waste was buried in 1987. The geostatistical analysis of 137Cs activity data in soils from Bugai et al. (2005) is first reconsidered to delimit the trench borders using georadar data as a covariable and to perform geostatistical simulations in order to evaluate the uncertainties of this inventory. 90Sr activity in soils is derived from 137Cs/154Eu and 90Sr/154Eu activity ratios in Chernobyl hot fuel particles (Bugai et al., 2003). Meanwhile, a coupled 1D non saturated/3D saturated transient transport model is constructed under the MELODIE software (IRSN, 2009). The previous 90Sr transport model developed by Bugai et al. (2012) did not take into account the effect of water table fluctuations highlighted by Van Meir et al. (2007) which may cause some discrepancies between model predictions and field observations. They are thus reproduced on a 1D vertical non saturated model. The equiprobable radionuclide localization maps produced by the geostatistical simulations are selected to illustrate different heterogeneities in the radionuclide inventory and are implemented in the 1D model. The obtained activity fluxes from all the 1D vertical models are then injected in a 3D

  10. Seasonal arsenic accumulation in stream sediments at a groundwater discharge zone.

    Science.gov (United States)

    MacKay, Allison A; Gan, Ping; Yu, Ran; Smets, Barth F

    2014-01-21

    Seasonal changes in arsenic and iron accumulation rates were examined in the sediments of a brook that receives groundwater discharges of arsenic and reduced iron. Clean glass bead columns were deployed in sediments for known periods over the annual hydrologic cycle to monitor changes in arsenic and iron concentrations in bead coatings. The highest accumulation rates occurred during the dry summer period (July-October) when groundwater discharges were likely greatest at the sample locations. The intermediate flow period (October-March), with higher surface water levels, was associated with losses of arsenic and iron from bead column coatings at depths below 2-6 cm. Batch incubations indicated iron releases from solids to be induced by biological reduction of iron (oxy)hydroxide solids. Congruent arsenic releases during incubation were limited by the high arsenic sorption capacity (0.536 mg(As)/mg(Fe)) of unreacted iron oxide solids. The flooded spring (March-June) with high surface water flows showed the lowest arsenic and iron accumulation rates in the sediments. Comparisons of accumulation rates across a shoreline transect were consistent with greater rates at regions exposed above surface water levels for longer times and greater losses at locations submerged below surface water. Iron (oxy)hydroxide solids in the shallowest sediments likely serve as a passive barrier to sorb arsenic released to pore water at depth by biological iron reduction.

  11. Quantifying submarine groundwater discharge in the coastal zone via multiple methods

    International Nuclear Information System (INIS)

    Burnett, W.C.; Aggarwal, P.K.; Aureli, A.; Bokuniewicz, H.; Cable, J.E.; Charette, M.A.; Kontar, E.; Krupa, S.; Kulkarni, K.M.; Loveless, A.; Moore, W.S.; Oberdorfer, J.A.; Oliveira, J.; Ozyurt, N.; Povinec, P.; Privitera, A.M.G.; Rajar, R.; Ramessur, R.T.; Scholten, J.; Stieglitz, T.; Taniguchi, M.; Turner, J.V.

    2006-01-01

    Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of near-shore waters. These discharges typically display significant spatial and temporal variability making assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise. A joint project of UNESCO and the International Atomic Energy Agency (IAEA) has examined several methods of SGD assessment and carried out a series of five intercomparison experiments in different hydrogeologic environments (coastal plain, karst, glacial till, fractured crystalline rock, and volcanic terrains). This report reviews the scientific and management significance of SGD, measurement approaches, and the results of the intercomparison experiments. We conclude that while the process is essentially ubiquitous in coastal areas, the assessment of its magnitude at any one location is subject to enough variability that measurements should be made by a variety of techniques and over large enough spatial and temporal scales to capture the majority of these changing conditions. We feel that all the measurement techniques described here are valid although they each have their own advantages and disadvantages. It is recommended that multiple approaches be applied whenever possible. In addition, a continuing effort is required in order to capture long-period tidal fluctuations, storm effects, and seasonal variations

  12. Quantifying submarine groundwater discharge in the coastal zone via multiple methods

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, W.C. [Department of Oceanography, Florida State University, Tallahassee, FL 32306 (United States); Aggarwal, P.K.; Kulkarni, K.M. [Isotope Hydrology Section, International Atomic Energy Agency (Austria); Aureli, A. [Department Water Resources Management, University of Palermo, Catania (Italy); Bokuniewicz, H. [Marine Science Research Center, Stony Brook University (United States); Cable, J.E. [Department Oceanography, Louisiana State University (United States); Charette, M.A. [Department Marine Chemistry, Woods Hole Oceanographic Institution (United States); Kontar, E. [Shirshov Institute of Oceanology (Russian Federation); Krupa, S. [South Florida Water Management District (United States); Loveless, A. [University of Western Australia (Australia); Moore, W.S. [Department Geological Sciences, University of South Carolina (United States); Oberdorfer, J.A. [Department Geology, San Jose State University (United States); Oliveira, J. [Instituto de Pesquisas Energeticas e Nucleares (Brazil); Ozyurt, N. [Department Geological Engineering, Hacettepe (Turkey); Povinec, P.; Scholten, J. [Marine Environment Laboratory, International Atomic Energy Agency (Monaco); Privitera, A.M.G. [U.O. 4.17 of the G.N.D.C.I., National Research Council (Italy); Rajar, R. [Faculty of Civil and Geodetic Engineering, University of Ljubljana (Slovenia); Ramessur, R.T. [Department Chemistry, University of Mauritius (Mauritius); Stieglitz, T. [Mathematical and Physical Sciences, James Cook University (Australia); Taniguchi, M. [Research Institute for Humanity and Nature (Japan); Turner, J.V. [CSIRO, Land and Water, Perth (Australia)

    2006-08-31

    Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of near-shore waters. These discharges typically display significant spatial and temporal variability making assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise. A joint project of UNESCO and the International Atomic Energy Agency (IAEA) has examined several methods of SGD assessment and carried out a series of five intercomparison experiments in different hydrogeologic environments (coastal plain, karst, glacial till, fractured crystalline rock, and volcanic terrains). This report reviews the scientific and management significance of SGD, measurement approaches, and the results of the intercomparison experiments. We conclude that while the process is essentially ubiquitous in coastal areas, the assessment of its magnitude at any one location is subject to enough variability that measurements should be made by a variety of techniques and over large enough spatial and temporal scales to capture the majority of these changing conditions. We feel that all the measurement techniques described here are valid although they each have their own advantages and disadvantages. It is recommended that multiple approaches be applied whenever possible. In addition, a continuing effort is required in order to capture long-period tidal fluctuations, storm effects, and seasonal variations. (author)

  13. Water movement through a shallow unsaturated zone in an inland arid region: Field drip irrigation experiment under matrix potential control

    Science.gov (United States)

    Zhou, T.; Han, D.; Song, X.

    2017-12-01

    It is vital to study soil water movement in unsaturated zone for evaluating and improving current irrigation mode for prevention and control of soil secondary salinization, especially in inland arid area, where is characterized by strong evaporation, poor drainage system and shallow water table depth. In this study, we investigated the applicability of drip irrigation under matrix potential control during cotton growth seasons in an inland arid region of northwest China. Combined physical observation with stable isotopes tracing method, we studied soil water flow system and recharge sources of shallow groundwater in heavy (Pilot 1) and light (Pilot 2) saline-alkali cotton fields. Evaporation depths (about 50-60 cm) are about the same for both pilots, but infiltration depths (about 60 cm for Pilot 1 and 150 cm for Pilot 2) are very different due to different soil texture, soil structure and soil salt content. Middle layer (about 100 cm thick) is a critical barrier for water exchange between surface and deep layer. Irrigation water is the major source (about 79.6% for Pilot 1 and 81.6% for Pilot 2), while evapotranspiration is the major sink (about 80.7% for Pilot 1 and 83.1% for Pilot 2) of unsaturated zone. The increase of soil water storage is not enough to make up the water shortage of middle layer and thus drip irrigation water doesn't recharge into groundwater for both pilots. Water table rise (about 60 cm for Pilot 1 and 50 cm for Pilot 2) could be caused by lateral groundwater flow instead of vertical infiltration. This irrigation mode could retard the water table rise in this region. However, improving horizontal drainage system may be indispensable for sustainable agriculture development. The study can provide important basis for soil secondary salinization prevention and agricultural water management in inland arid areas.

  14. Rapid Analysis of Eukaryotic Bioluminescence to Assess Potential Groundwater Contamination Events

    Directory of Open Access Journals (Sweden)

    Zacariah L. Hildenbrand

    2015-01-01

    Full Text Available Here we present data using a bioluminescent dinoflagellate, Pyrocystis lunula, in a toxicological bioassay to rapidly assess potential instances of groundwater contamination associated with natural gas extraction. P. lunula bioluminescence can be quantified using spectrophotometry as a measurement of organismal viability, with normal bioluminescent output declining with increasing concentration(s of aqueous toxicants. Glutaraldehyde and hydrochloric acid (HCl, components used in hydraulic fracturing and shale acidization, triggered significant toxicological responses in as little as 4 h. Conversely, P. lunula was not affected by the presence of arsenic, selenium, barium, and strontium, naturally occurring heavy metal ions potentially associated with unconventional drilling activities. If exogenous compounds, such as glutaraldehyde and HCl, are thought to have been introduced into groundwater, quantification of P. lunula bioluminescence after exposure to water samples can serve as a cost-effective detection and risk assessment tool to rapidly assess the impact of putative contamination events attributed to unconventional drilling activity.

  15. Uranium-isotope variations in groundwaters of the Floridan aquifer and boulder zone of South Florida

    International Nuclear Information System (INIS)

    Cowart, J.B.; Osmond, J.K.

    1978-01-01

    Water samples from four wells from the main Floridan aquifer (300-400 m below mean sea level) in southeast Florida exhibit 234 U/ 238 U activity ratios that are significantly lower than the secular equilibrium value of 1.00. Such anomalous values have been observed previously only in waters from sedimentary aquifers in the near-surface oxidizing environments. These four wells differ from six others, all producing from the same general horizon, in being located in cavernous highly transmissive zones

  16. Study on groundwater quality and potential use in shallow coastal East Surabaya

    International Nuclear Information System (INIS)

    Wahyudi; Arief Setiyono; Onie Wiwid Jayanthi

    2014-01-01

    The eastern part of coastal area is one of the fast growing urban area in Surabaya. Increasing in population and industrial growth have driven increasing demands for natural resources, particularly water. The objectives of this study are to identify the quality of the coastal groundwater through in situ measurement and laboratory analyses, and to find out its potential to be utilized as a source of water for coastal aquaculture. Groundwater samples from 70 sampling station have been taken from east Surabaya coastal area. Measurements of the temperature, pH, and dissolved oxygen of the samples carried out directly in situ, and measurements of concentration of nitrate, nitrite, ammonia, sulphide, and phosphate conducted in the Environmental Laboratory of ITS. The results show that coastal groundwater in west part of the study area, in only very small area, can be used as a drinking water, and in almost all area of the east Surabaya coastal area is not permitted. In the central and south part can be utilized as a source of the coastal aquaculture, however in the north part is not potential, in the central area is medium, and in the south part is categorized as a high potential. (author)

  17. Geological and geophysical evaluation of the Ajana area’s groundwater potential, southwestern Nigeria

    Directory of Open Access Journals (Sweden)

    O.M Ajibade

    2011-06-01

    Full Text Available Acombined geological and geophysical evaluation was madeof the groundwater potential of the Ajana, RemoNorth area in south-western Nigeria; the geology and other structural features of the rocks there strongly influenced and correlated the aquifers' storability and transmissivity. Geological mapping revealed that the area was made up of granite, quartzite and varieties of gneiss, some of which have good secondary porosity and permeability. Ten vertical electric soundings (VES stations were established using a Schlumberger electrode array. Five geoelectric layers consisting of topsoil, sand,
    clayey-sandy, fractured / weathered basement and fresh bedrock were delineated. The aquifer layers were the 38.3m thick 283 ?m resistivity sand/sandy clay and 55 - 518 ?m resistivity fractured/weathered basement. Other geoelectric parameters used in evaluating the area's hydrogeological potential included curve type, anisotropy coefficient and reflection coefficient - The QH curve type was predominant in the area. The anisotropy Coefficients suggested VES stations having high groundwater potential ranging from 1.4 - 1.56; while the reflection coefficients for the area ranged from 0.21 - 0.99. The overall results showed that VES stations 8, 9 and 10 could be possible groundwater sources having high expected yield.

  18. Potential Climatic Zoning of Wheat (Triticum aestivum L. Golestan Province

    Directory of Open Access Journals (Sweden)

    Afrough Sadat Baniaghil

    2017-12-01

    digital elevation model (DEM with a topo-to-raster function. Method of study In this study, the first agro-ecological requirements and of wheat were determined based on scientific resources. Studied climatic variables were included average, minimum and maximum temperatures, precipitation in the date planting and during growth season of crop. Data of the last 10 years were collected and recorded from 25 stations located within the study area. The standardization of data was used from fuzzy method and Analytic Hierarchy Process (AHP was used for weighting the criteria. Finally, using weighted linear combination (WLC in the software IDRISI, wheat cultivation potential map was prepared. Results and Discussion The results showed that the weighted criteria of AHP, the amount of precipitation during the growing season had the highest amount with 0.3407 and minimum temperature in the emergence stage with 0.0306 had the lowest coefficient in the rankings. The digital environmental layers overlaid and integration in GIS media then zoning of lands carried out in 4 classes (high suitable, suitable, less suitable and unsuitable. The results showed that 9.54% and 54.53% of this area were high suitable and suitable for wheat cropping, respectively. Conclusion In the output map from weighted linear combination, the located lands in East, Southeastern, South and Southwest had the lowest potential production for wheat. These areas were consisted of steep slopes, highest elevation, less precipitation and less favorable area in terms of areas which had unfavorable climate areas and other areas that located in the Northeastern, center and Northwest of the province had the best potential for wheat production which can be said cause of sufficient amount precipitation, low slope and elevation, favorable soil and temperature.

  19. Hydrogeophysical imaging of deposit heterogeneity and groundwater chemistry changes during DNAPL source zone bioremediation.

    Science.gov (United States)

    Chambers, J E; Wilkinson, P B; Wealthall, G P; Loke, M H; Dearden, R; Wilson, R; Allen, D; Ogilvy, R D

    2010-10-21

    Robust characterization and monitoring of dense nonaqueous phase liquid (DNAPL) source zones is essential for designing effective remediation strategies, and for assessing the efficacy of treatment. In this study high-resolution cross-hole electrical resistivity tomography (ERT) was evaluated as a means of monitoring a field-scale in-situ bioremediation experiment, in which emulsified vegetable oil (EVO) electron donor was injected into a trichloroethene source zone. Baseline ERT scans delineated the geometry of the interface between the contaminated alluvial aquifer and the underlying mudstone bedrock, and also the extent of drilling-induced physical heterogeneity. Time-lapse ERT images revealed major preferential flow pathways in the source and plume zones, which were corroborated by multiple lines of evidence, including geochemical monitoring and hydraulic testing using high density multilevel sampler arrays within the geophysical imaging planes. These pathways were shown to control the spatial distribution of the injected EVO, and a bicarbonate buffer introduced into the cell for pH control. Resistivity signatures were observed within the preferential flow pathways that were consistent with elevated chloride levels, providing tentative evidence from ERT of the biodegradation of chlorinated solvents. Copyright © 2010 S. Yamamoto. Published by Elsevier B.V. All rights reserved.

  20. Effects of Low-Permeability Layers in the Hyporheic Zone on Oxygen Consumption Under Losing and Gaining Groundwater Flow Conditions

    Science.gov (United States)

    Arnon, S.; Krause, S.; Gomez-Velez, J. D.; De Falco, N.

    2017-12-01

    Recent studies at the watershed scale have demonstrated the dominant role that river bedforms play in driving hyporheic exchange and constraining biogeochemical processes along river corridors. At the reach and bedform scales, modeling studies have shown that sediment heterogeneity significantly modifies hyporheic flow patterns within bedforms, resulting in spatially heterogeneous biogeochemical processes. In this work, we summarize a series of flume experiments to evaluate the effect that low-permeability layers, representative of structural heterogeneity, have on hyporheic exchange and oxygen consumption in sandy streambeds. In this case, we systematically changed the geometry of the heterogeneities, the surface channel flow driving the exchange, and groundwater fluxes (gaining/losing) modulating the exchange. The flume was packed with natural sediments, which were amended with compost to minimize carbon limitations. Structural heterogeneities were represented by continuous and discontinuous layers of clay material. Flow patterns were studied using dye imaging through the side walls. Oxygen distribution in the streambed was measured using planar optodes. The experimental observations revealed that the clay layer had a significant effect on flow patterns and oxygen distribution in the streambed under neutral and losing conditions. Under gaining conditions, the aerobic zone was limited to the upper sections of the bedform and thus was less influenced by the clay layers that were located at a depth of 1-3 cm below the water-sediment interface. We are currently analyzing the results with a numerical flow and transport model to quantify the reactions rates under the different flow conditions and spatial sediment structures. Our preliminary results enable us to show the importance of the coupling between flow conditions, local heterogeneity within the streambed and oxygen consumption along bed forms and are expected to improve our ability to model the effect of stream-groundwater

  1. Prevalence of pathogenic bacteria in surface and groundwater of urban and rural zones of El-Gaza generative, Egypt

    International Nuclear Information System (INIS)

    Abo-State, M.A.M.; El-Khatat, A.M.R.; El-Shahat, M.F.

    2005-01-01

    Thirty three water and soil samples, from the urban and rural zones of El-Giza, Egypt, were used to evaluate the microbiological quality of soil, surface and groundwater samples. Total aerobic bacterial count of groundwater ranged from 2 x10 4 to 1. 2 x 10 7 CFU/ml, which were B. cereus (1 x10 2 - 1 x10 4 CFU/ml), Enterobacteriacea (1 x 10 2 - 2 x 10 6 CFU/ml), E.Coli (0 - 9 x 10 4 CFU/ml), Pseudomonas (9 x 10 2 - 3 x 10 6 CFU/ml), total Staph. (0 - 5.6 x 10 3 CFU/ml) and Staph. aureus (0 - 5 x10 3 CFU/ml). Meanwhile, surface water contained total aerobic bacterial count in the range of 1 x 10 5 -9 x 10 6 CFU/ml, which where l x10 2 - 4 x 10 3 CFU/ml B. cereus, 3.9 x 10''3 -1.6 x 10 6 CFU/ml Enterobacteriacea, 1 x 10 2 - 2.9 x 10 4 CFU/ml Ent. faecalis, 5 x 10 2 - 1.1 x 10 5 CFU/ml E. coli, 4.9 x 10 4 - 1.1 x 10 4 CFU/ml Pseudomonas, 3 x 10 2 - 4 x 10 4 CFU/ml total Staph. and 1 x 10 -1 x 10 4 CFU/ml Staph. aureus. Salmonella was detected in almost all surface water samples except in one sample. No Ent. faecalis, total Staph. and Staph. aureus or Salmonella had been detected in soil samples except in one sample, which recorded 4 x10 3 CFU/ml Ent. faecalis. Inactivation of pathogenic bacteria by heat treatment revealed that heating of water for 5 minutes at 100 degree C (boiling) got rid completely of pathogens except the spore forming Bacilli which still persisted

  2. Modeling the effects of the variability of temperature-related dynamic viscosity on the thermal-affected zone of groundwater heat-pump systems

    Science.gov (United States)

    Lo Russo, Stefano; Taddia, Glenda; Cerino Abdin, Elena

    2018-01-01

    Thermal perturbation in the subsurface produced in an open-loop groundwater heat pump (GWHP) plant is a complex transport phenomenon affected by several factors, including the exploited aquifer's hydrogeological and thermal characteristics, well construction features, and the temporal dynamics of the plant's groundwater abstraction and reinjection system. Hydraulic conductivity has a major influence on heat transport because plume propagation, which occurs primarily through advection, tends to degrade following conductive heat transport and convection within moving water. Hydraulic conductivity is, in turn, influenced by water reinjection because the dynamic viscosity of groundwater varies with temperature. This paper reports on a computational analysis conducted using FEFLOW software to quantify how the thermal-affected zone (TAZ) is influenced by the variation in dynamic viscosity due to reinjected groundwater in a well-doublet scheme. The modeling results demonstrate non-negligible groundwater dynamic-viscosity variation that affects thermal plume propagation in the aquifer. This influence on TAZ calculation was enhanced for aquifers with high intrinsic permeability and/or substantial temperature differences between abstracted and post-heat-pump-reinjected groundwater.

  3. Potential impacts on groundwater resources of deep CO2 storage: natural analogues for assessing potential chemical effects

    Science.gov (United States)

    Lions, J.; Gale, I.; May, F.; Nygaard, E.; Ruetters, H.; Beaubien, S.; Sohrabi, M.; Hatzignatiou, D. G.; CO2GeoNet Members involved in the present study Team

    2011-12-01

    Carbon dioxide Capture and Storage (CCS) is considered as one of the promising options for reducing atmospheric emissions of CO2 related to human activities. One of the main concerns associated with the geological storage of CO2 is that the CO2 may leak from the intended storage formation, migrate to the near-surface environment and, eventually, escape from the ground. This is a concern because such leakage may affect aquifers overlying the storage site and containing freshwater that may be used for drinking, industry and agriculture. The IEA Greenhouse Gas R&D Programme (IEAGHG) recently commissioned the CO2GeoNet Association to undertake a review of published and unpublished literature on this topic with the aim of summarizing 'state of the art' knowledge and identifying knowledge gaps and research priorities in this field. Work carried out by various CO2GeoNet members was also used in this study. This study identifies possible areas of conflict by combining available datasets to map the global and regional superposition of deep saline formations (DSF) suitable for CO2 storage and overlying fresh groundwater resources. A scenario classification is developed for the various geological settings where conflict could occur. The study proposes two approaches to address the potential impact mechanisms of CO2 storage projects on the hydrodynamics and chemistry of shallow groundwater. The first classifies and synthesizes changes of water quality observed in natural/industrial analogues and in laboratory experiments. The second reviews hydrodynamic and geochemical models, including coupled multiphase flow and reactive transport. Various models are discussed in terms of their advantages and limitations, with conclusions on possible impacts on groundwater resources. Possible mitigation options to stop or control CO2 leakage are assessed. The effect of CO2 pressure in the host DSF and the potential effects on shallow aquifers are also examined. The study provides a review of

  4. Investigation of the groundwater composition at potential radioactive waste disposal sites in Sweden

    International Nuclear Information System (INIS)

    Wikberg, P.T.

    1984-02-01

    Within an investigation program of sites suitable for an underground repository for spent nuclear fuel the groundwater has been characterized. Until now seven areas have been investigated. The groundwater has been pumped up from several isolated sections at depth of 100 m to 600 m in boreholes in each area. Each test section has been pumped continuously for at least two weeks. During the pumping period the water was characterized in the field and sampled for later analysis. Most of the characterized waters are non saline and the concentration of the different constituents varies within a rather narrow interval. Saline waters with much higher concentrations of chloride, sulphate, sodium and calcium have been encountered. The groundwater characterization includes field monitoring of the physico-chemical parameters pH, redox potential, free sulphide concentration, dissolved oxygen concentration and conductivity. These parameters are measured in a flow through cell where the water passes before coming in contact with the air. The redox potential measurements have been successful. A new equipment for measurements in the sampling section has been constructed. Preliminary tests have given very promising results

  5. Evaluation of Logistic Regression and Multivariate Adaptive Regression Spline Models for Groundwater Potential Mapping Using R and GIS

    Directory of Open Access Journals (Sweden)

    Soyoung Park

    2017-07-01

    Full Text Available This study mapped and analyzed groundwater potential using two different models, logistic regression (LR and multivariate adaptive regression splines (MARS, and compared the results. A spatial database was constructed for groundwater well data and groundwater influence factors. Groundwater well data with a high potential yield of ≥70 m3/d were extracted, and 859 locations (70% were used for model training, whereas the other 365 locations (30% were used for model validation. We analyzed 16 groundwater influence factors including altitude, slope degree, slope aspect, plan curvature, profile curvature, topographic wetness index, stream power index, sediment transport index, distance from drainage, drainage density, lithology, distance from fault, fault density, distance from lineament, lineament density, and land cover. Groundwater potential maps (GPMs were constructed using LR and MARS models and tested using a receiver operating characteristics curve. Based on this analysis, the area under the curve (AUC for the success rate curve of GPMs created using the MARS and LR models was 0.867 and 0.838, and the AUC for the prediction rate curve was 0.836 and 0.801, respectively. This implies that the MARS model is useful and effective for groundwater potential analysis in the study area.

  6. Groundwater potential zonation by Remote Sensing and GIS techniques and its relation to the Groundwater level in the Coastal part of the Arani and Koratalai River Basin, Southern India

    Directory of Open Access Journals (Sweden)

    S Suganthi

    2013-07-01

    Full Text Available Groundwater is being pumped extensively from the coastal part of the Arani and Koratalai River Basin, Tamil Nadu, India for irrigation and water supply to the city of Chennai. The objective of this study is to delineate the groundwater potential zones of this area using Remote Sensing (RS and Geographic Information System (GIS techniques. Weighted overlay analysis was used to demarcate the ground- water potential zones. Various thematic layers such as geology, geomorphology, soil, lineament density, drainage density, rainfall and landuse maps were prepared. The geological map was prepared using a Geological Survey of India (GSI district resource map. Indian Remote Sensing System Linear Imaging Self-scanning Sensor III (IRS-1D LISS III satellite imagery was used to prepare the geomorphology, soil, lineament density, drainage density, and landuse maps. The final groundwater potential map was prepared by assigning appropriate weightage to different thematic maps and adding them to the final groundwater potential map. The derived groundwater potential map was overlaid with the groundwater level and location of well fields for validation. The map prepared will help in systematic and proper development of groundwater resources in this area to meet the growing water requirements of the city of Chennai.  Resumen Aguas subterráneas se bombean en gran cantidad desde la parte costera en las cuencas de los ríos Arani, en Tamil Nadu, India, para el riego y el aprovisionamiento de agua a la ciudad de Chennai. El objetivo de este estudio es delinear las zonas potenciales de aguas subterráneas en esta área a través de sistemas de Teledeteción (RS y de Información Geográfica (GIS. Se hizo un análisis sobrepuesto compensado para demarcar las zonas con posibilidad de tener aguas subterráneas. Se prepararon mapas de uso de la tierra con varios elementos temáticos como geología, geomorfología, terreno, densidad de lineamiento, densi- dad de drenaje y

  7. Silica precipitation potentially controls earthquake recurrence in seismogenic zones.

    Science.gov (United States)

    Saishu, Hanae; Okamoto, Atsushi; Otsubo, Makoto

    2017-10-17

    Silica precipitation is assumed to play a significant role in post-earthquake recovery of the mechanical and hydrological properties of seismogenic zones. However, the relationship between the widespread quartz veins around seismogenic zones and earthquake recurrence is poorly understood. Here we propose a novel model of quartz vein formation associated with fluid advection from host rocks and silica precipitation in a crack, in order to quantify the timescale of crack sealing. When applied to sets of extensional quartz veins around the Nobeoka Thrust of SW Japan, an ancient seismogenic splay fault, our model indicates that a fluid pressure drop of 10-25 MPa facilitates the formation of typical extensional quartz veins over a period of 6.6 × 10 0 -5.6 × 10 1 years, and that 89%-100% of porosity is recovered within ~3 × 10 2 years. The former and latter sealing timescales correspond to the extensional stress period (~3 × 10 1 years) and the recurrence interval of megaearthquakes in the Nankai Trough (~3 × 10 2 years), respectively. We therefore suggest that silica precipitation in the accretionary wedge controls the recurrence interval of large earthquakes in subduction zones.

  8. An Isotopic view of water and nitrogen transport through the vadose zone in Oregon's southern Willamette Valley's Groundwater Management Area

    Science.gov (United States)

    Background/Question/MethodsGroundwater nitrate contamination affects thousands of households in Oregon's southern Willamette Valley and many more across the Pacific Northwest. The southern Willamette Valley Groundwater Management Area (SWV GWMA) was established in 2004 due to nit...

  9. Implications of Self-Potential Distribution for Groundwater Flow System in a Nonvolcanic Mountain Slope

    Directory of Open Access Journals (Sweden)

    Tada-nori Goto

    2012-01-01

    Full Text Available Self-potential (SP measurements were conducted at Mt. Tsukuba, Japan, which is a nonvolcanic mountain, to infer groundwater flow system in the mountain. Survey routes were set around the northern slope, and the reliability of observed SP anomaly was checked by using SP values along parallel survey routes; the error was almost within 10 mV. The FFT analysis of the spatial SP distribution allows us a separation of raw data into two components with shorter and longer wavelength. In the shorter (altitudinal wavelength than ∼200 meters, several positive SP peaks of more than 100 mV in magnitude are present, which indicate shallow perched water discharges along the slope. In the regional SP pattern of longer wavelength, there are two major perturbations from the general trend reflecting the topographic effect. By comparing the SP and hydrological data, the perturbation around the foothill is interpreted to be caused by heterogeneous infiltration at the ground surface. The perturbation around the summit is also interpreted to be caused by heterogeneous infiltration process, based on a simplified numerical modeling of SP. As a result, the SP pattern is well explained by groundwater flow and infiltration processes. Thus, SP data is thought to be very useful for understanding of groundwater flow system on a mountain scale.

  10. Subsurface Transport Behavior of Micro-Nano Bubbles and Potential Applications for Groundwater Remediation

    Directory of Open Access Journals (Sweden)

    Hengzhen Li

    2013-12-01

    Full Text Available Micro-nano bubbles (MNBs are tiny bubbles with diameters on the order of micrometers and nanometers, showing great potential in environmental remediation. However, the application is only in the beginning stages and remains to be intensively studied. In order to explore the possible use of MNBs in groundwater contaminant removal, this study focuses on the transport of MNBs in porous media and dissolution processes. The bubble diameter distribution was obtained under different conditions by a laser particle analyzer. The permeability of MNB water through sand was compared with that of air-free water. Moreover, the mass transfer features of dissolved oxygen in water with MNBs were studied. The results show that the bubble diameter distribution is influenced by the surfactant concentration in the water. The existence of MNBs in pore water has no impact on the hydraulic conductivity of sand. Furthermore, the dissolved oxygen (DO in water is greatly increased by the MNBs, which will predictably improve the aerobic bioremediation of groundwater. The results are meaningful and instructive in the further study of MNB research and applications in groundwater bioremediation.

  11. Assessment of the potential for groundwater contamination using the DRASTIC/EGIS technique, Cheongju area, South Korea

    Science.gov (United States)

    Kim, Youn Jong; Hamm, Se-Yeong

    Groundwater contamination is becoming a major environmental problem in South Korea with the marked expansion of the industrial base and the explosive growth of the population. Even in rural areas, the increased use of fertilizers and pesticides, the presence of acid-mine drainage, and increase of volumes of domestic wastewaters are adding to groundwater pollution. The DRASTIC/EGIS model was used to evaluate the potential for groundwater contamination in the Cheongju city area, the first of several pilot studies. The model allows the designation of hydrogeologic settings within the study area, based on a composite description of all the major geologic and hydrogeologic factors for each setting. Then, a scheme for relative ranking of the hydrogeologic factors is applied to evaluate the relative vulnerability to groundwater contamination of each hydrogeologic setting. DRASTIC/EGIS can serve as a tool to evaluate pollution potential and so facilitate programs to protect groundwater resources. Résumé La contamination de l'eau souterraine devient un problème environnemental majeur en Corée du Sud, en relation avec le développement industriel bien marqué et l'explosion démographique. Meme dans les zones rurales, l'utilisation accrue d'engrais et de pesticides, le drainage acide de mines et les rejets croissants d'eaux usées contribuent à la pollution des nappes. Le modèle DRASTIC/EGIS a été utilisé pour évaluer le potentiel de contamination des eaux souterraines dans la région de la ville de Cheongju, la première de plusieurs régions pilotes. Le modèle permet de définir des ensembles hydrogéologiques dans la région étudiée, à partir de la description composite de tous les facteurs géologiques et hydrogéologiques essentiels pour chaque ensemble. Ensuite, un schéma pour le classement des facteurs hydrogéologiques est mis en oeuvre pour évaluer la vulnérabilité relative à la contamination des eaux souterraines pour chaque ensemble. DRASTIC

  12. Potential Offshore Submarine Groundwater in the Albufeira-Ribeira de Quarteira aquifer system (Algarve, Portugal)

    Science.gov (United States)

    Hugman, Rui; Stigter, Tibor; Monteiro, Jose Paulo

    2015-04-01

    The Albufeira-Ribeira de Quarteira aquifer system on the south coast of Portugal is an important source of groundwater for agriculture and tourism, as well as contributing to significant freshwater discharge along the coast in the form of inter- and sub-tidal springs and maintaining groundwater dependent ecosystems along the Quarteira stream. Submarine groundwater discharge (SGD) in the area was investigated within the scope of a multidisciplinary research project FREEZE (PTDC/MAR/102030/2008) which aimed to identify and characterize the effects of the hydrological/hydrogeological conditions on associated ecosystems. As well as near shore submarine springs, signs of SGD were found several kilometres from the shoreline during offshore CTD and geophysical surveys. On-land geophysical and offshore seismic surveys supplied data to update the 3D hydrogeological conceptual model of the aquifer system. Numerical models were applied to test the possibility of an offshore continuation of fresh groundwater over several kilometres under local conditions. Due to the high computational demand of variable density modelling, in an initial phase simplified 2D cross section models were used to test the conceptual model and reduce uncertainty in regards to model parameters. Results confirm the potential for SGD several kilometres from the coast within a range of acceptable values of hydraulic conductivity and recharge of the system. This represents the initial step in developing and calibrating a 3D regional scale model of the system, which aims to supply an estimate of the spatial distribution of SGD as well as serve as a decision support tool for the local water resources management agency.

  13. Salinization of the soil solution decreases the further accumulation of salt in the root zone of the halophyte Atriplex nummularia Lindl. growing above shallow saline groundwater.

    Science.gov (United States)

    Alharby, Hesham F; Colmer, Timothy D; Barrett-Lennard, Edward G

    2018-01-01

    Water use by plants in landscapes with shallow saline groundwater may lead to the accumulation of salt in the root zone. We examined the accumulation of Na + and Cl - around the roots of the halophyte Atriplex nummularia Lindl. and the impacts of this increasing salinity for stomatal conductance, water use and growth. Plants were grown in columns filled with a sand-clay mixture and connected at the bottom to reservoirs containing 20, 200 or 400 mM NaCl. At 21 d, Na + and Cl - concentrations in the soil solution were affected by the salinity of the groundwater, height above the water table and the root fresh mass density at various soil depths (P soil solution therefore had a feedback effect on further salinization within the root zone. © 2017 John Wiley & Sons Ltd.

  14. Investigation of Eh, pH and corrosion potential of steel in anoxic groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Peat, R.; Brabon, S.; Fennell, P.A.H.; Rance, A.P.; Smart, N.R. [AEA Technology (United Kingdom)

    2001-01-01

    SKB intend to dispose of the spent nuclear fuel produced by Sweden's eleven nuclear reactors by encapsulating it in corrosion-resistant copper canisters containing a cast iron or carbon steel insert. After encapsulation, the fuel will be transported to a geological repository, where the containers will be deposited at a depth of 500 to 700 m in granitic rock and surrounded by a bentonite clay backfill material. If, or when the copper corrosion shield fails, the iron insert will be in contact with oxygen-free water and hydrogen-producing, anaerobic corrosion will start. SKB have carried out modelling calculations of the oxidising power (Eh) of groundwater and wished to confirm the results by carrying out experimental measurements. The objective of the work described in this report was to demonstrate the feasibility of monitoring Eh, pH and corrosion potential in a cell where anaerobic corrosion of steel in artificial groundwater was occurring. To this end, gas cells similar to those used previously for anaerobic corrosion rate measurements were used as the basis for the design of an electrochemical cell. The cell incorporated electrodes to provide an in situ measurement of the redox potential, Eh, the pH and the corrosion potential of carbon steel. The main stages of the work were: Design of the electrochemical cell; Preparation of silver-silver chloride and calomel reference electrodes; Calibration of the reference electrodes and commercial glass pH electrodes against a standard hydrogen electrode; Assembly of the test cell under anoxic conditions; Monitoring the cell before and after the addition of steel wires to the test solution. Details of the design of the test cell and the experimental procedures used are described. Two cells were set up. The first employed a silver-silver chloride reference electrode, which was failed after approximately 400 hours, and the second cell therefore used a calomel reference electrode. The results of the electrode

  15. On the development of a three-dimensional finite-element groundwater flow model of the saturated zone, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Czarnecki, J.B.; Faunt, C.C.; Gable, C.W.; Zyvoloski, G.A.

    1996-01-01

    Development of a preliminary three-dimensional model of the saturated zone at Yucca Mountain, the potential location for a high-level nuclear waste repository, is presented. The development of the model advances the technology of interfacing: (1)complex three-dimensional hydrogeologic framework modeling; (2) fully three-dimensional, unstructured, finite-element mesh generation; and (3) groundwater flow, heat, and transport simulation. The three-dimensional hydrogeologic framework model is developed using maps, cross sections, and well data. The framework model data are used to feed an automated mesh generator, designed to discretize irregular three-dimensional solids,a nd to assign materials properties from the hydrogeologic framework model to the tetrahedral elements. The mesh generator facilitated the addition of nodes to the finite-element mesh which correspond to the exact three-dimensional position of the potentiometric surface based on water-levels from wells. A ground water flow and heat simulator is run with the resulting finite- element mesh, within a parameter-estimation program. The application of the parameter-estimation program is designed to provide optimal values of permeability and specified fluxes over the model domain to minimize the residual between observed and simulated water levels

  16. Implications of Self-Potential Distribution for Groundwater Flow System in a Nonvolcanic Mountain Slope

    OpenAIRE

    Goto, Tada-nori; Kondo, Kazuya; Ito, Rina; Esaki, Keisuke; Oouchi, Yasuo; Abe, Yutaka; Tsujimura, Maki

    2012-01-01

    Self-potential (SP) measurements were conducted at Mt. Tsukuba, Japan, which is a nonvolcanic mountain, to infer groundwater flow system in the mountain. Survey routes were set around the northern slope, and the reliability of observed SP anomaly was checked by using SP values along parallel survey routes; the error was almost within 10 mV. The FFT analysis of the spatial SP distribution allows us a separation of raw data into two components with shorter and longer wavelength. In the shorter ...

  17. Geostatistical analysis of prevailing groundwater conditions and potential solute migration at Elstow, Bedfordshire

    International Nuclear Information System (INIS)

    MacKay, R.; Cooper, T.A.; Porter, J.D.; O'Connell, P.E.; Metcalfe, A.V.

    1988-06-01

    A geostatistical approach is applied in a study of the potential migration of contaminants from a hypothetical waste disposal facility near Elstow, Bedfordshire. A deterministic numerical model of groundwater flow in the Kellaways Sands formation and adjacent layers is coupled with geostatistical simulation of the heterogeneous transmissivity field of this principal formation. A particle tracking technique is used to predict the migration pathways for alternative realisations of flow. Alternative statistical descriptions of the spatial structure of the transmissivity field are implemented and the temporal and spatial distributions of escape of contaminants to the biosphere are investigated. (author)

  18. Potential for Methanosarcina to contribute to uranium reduction during acetate-promoted groundwater bioremediation

    DEFF Research Database (Denmark)

    Holmes, Dawn E; Orellana, Roberto; Giloteaux, Ludovic

    2017-01-01

    Previous studies of in situ bioremediation of uranium-contaminated groundwater with acetate injections have focused on the role of Geobacter species in U(VI) reduction because of a lack of other abundant known U(VI)-reducing microorganisms. Monitoring the levels of methyl CoM reductase subunit...... an important role in the long-term bioremediation of uranium-contaminated aquifers after depletion of Fe(III) oxides limits the growth of Geobacter species. The results also suggest that Methanosarcina have the potential to influence uranium geochemistry in a diversity of anaerobic sedimentary environments....

  19. Spatial variability analysis of combining the water quality and groundwater flow model to plan groundwater and surface water management in the Pingtung plain

    Science.gov (United States)

    Chen, Ching-Fang; Chen, Jui-Sheng; Jang, Cheng-Shin

    2014-05-01

    As a result of rapid economic growth in the Pingtung Plain, the use of groundwater resources has changed dramatically. The groundwater is quite rich in the Pingtung plain and the most important water sources. During the several decades, a substantial amount of groundwater has been pumped for the drinking, irrigation and aquaculture water supplies. However, because the sustainable use concept of groundwater resources is lack, excessive pumping of groundwater causes the occurrence of serious land subsidence and sea water intrusion. Thus, the management and conservation of groundwater resources in the Pingtung plain are considerably critical. This study aims to assess the conjunct use effect of groundwater and surface water in the Pingtung plain on recharge by reducing the amount of groundwater extraction. The groundwater quality variability and groundwater flow models are combined to spatially analyze potential zones of groundwater used for multi-purpose in the Pingtung Plain. First, multivariate indicator kriging (MVIK) is used to analyze spatial variability of groundwater quality based on drinking, aquaculture and irrigation water quality standards, and probabilistically delineate suitable zones in the study area. Then, the groundwater flow model, Processing MODFLOW (PMWIN), is adopted to simulate groundwater flow. The groundwater flow model must be conducted by the calibration and verification processes, and the regional groundwater recovery is discussed when specified water rights are replaced by surface water in the Pingtung plain. Finally, the most suitable zones of reducing groundwater use are determined for multi-purpose according to combining groundwater quality and quantity. The study results can establish a sound and low-impact management plan of groundwater resources utilization for the multi-purpose groundwater use, and prevent decreasing ground water tables, and the occurrence of land subsidence and sea water intrusion in the Pingtung plain.

  20. SWB Groundwater Recharge Analysis, Catalina Island, California: Assessing Spatial and Temporal Recharge Patterns Within a Mediterranean Climate Zone

    Science.gov (United States)

    Harlow, J.

    2017-12-01

    Groundwater recharge quantification is a key parameter for sustainable groundwater management. Many recharge quantification techniques have been devised, each with advantages and disadvantages. A free, GIS based recharge quantification tool - the Soil Water Balance (SWB) model - was developed by the USGS to produce fine-tuned recharge constraints in watersheds and illuminate spatial and temporal dynamics of recharge. The subject of this research is to examine SWB within a Mediterranean climate zone, focusing on the Catalina Island, California. This project relied on publicly available online resources with the exception the geospatial processing software, ArcGIS. Daily climate station precipitation and temperature data was obtained from the Desert Research Institute for the years 2008-2014. Precipitation interpolations were performed with ArcGIS using the Natural Neighbor method. The USGS-National Map Viewer (NMV) website provided a 30-meter DEM - to interpolate high and low temperature ASCII grids using the Temperature Lapse Rate (TLR) method, to construct a D-8 flow direction grid for downhill redirection of soil-moisture saturated runoff toward non-saturated cells, and for aesthetic map creation. NMV also provided a modified Anderson land cover classification raster. The US Department of Agriculture-National Resource Conservation Service (NRCS) Web Soil Survey website provided shapefiles of soil water capacity and hydrologic soil groups. The Hargreaves and Samani method was implemented to determine evapotranspiration rates. The resulting SWB output data, in the form of ASCII grids are easily added to ArcGIS for quick visualization and data analysis (Figure 1). Calculated average recharge for 2008-2014 was 3537 inches/year, or 0.0174 acre feet/year. Recharge was 10.2% of the islands gross precipitation. The spatial distribution of the most significant recharge is in hotspots which dominate the residential hills above Avalon, followed by grassy/unvegetated areas

  1. Denitrification Potential, Root Biomass, and Organic Matter in Degraded and Restored Urban Riparian Zones

    Science.gov (United States)

    Hydrologic changes associated with urbanization often lead to lower water tables and drier, more aerobic soils in riparian zones. These changes reduce the potential for denitrification, an anaerobic microbial process that converts nitrate, a common water pollutant, into nitrogen...

  2. Degradation of ground ice in a changing climate: the potential impact of groundwater flow

    Science.gov (United States)

    de Grandpré, I.; Fortier, D.; Stephani, E.

    2011-12-01

    Climate changes affecting the North West portion of Canada alter the thermal state of the permafrost and promote ground ice degradation. Melting of ground ice leads to greater water flow into the ground and to significant hydraulic changes (i.e. drainage of peatland and lakes, triggering of thermokarst and new groundwater flow patterns). Road infrastructures built on permafrost are particularly sensitive to permafrost degradation. Road construction and maintenance induce heat flux into the ground by the increase of solar radiation absorption (comparing to natural ground), the increase of snow cover on side slopes, the infiltration of water in embankment material and the migration of surface water in the active layer. The permafrost under the roads is therefore submitted to a warmer environment than in natural ground and his behavior reflects how the permafrost will act in the future with the global warming trend. The permafrost degradation dynamic under a road was studied at the Beaver Creek (Yukon) experimental site located on the Alaska Highway. Permafrost was characterized as near-zero Celcius and highly susceptible to differential thaw-settlement due to the ground ice spatial distribution. Ice-rich cryostructures typical of syngenetic permafrost (e.g. microlenticular) were abundant in the upper and lower cryostratigraphic units of fine-grained soils (Units 1, 2A, and 2C). The middle ice-poor silt layer (Unit 2B) characterized by porous cryostructure comprised the top of a buried ice-wedge network extending several meters in the underlying layers and susceptible to degradation by thermo-erosion. These particular features of the permafrost at the study site facilitated the formation of taliks (unfrozen zones) under the road which leaded to a greater water flow. We believe that water flow is promoting an acceleration of permafrost degradation by advective heat transfer. This process remains poorly studied and quantified in permafrost environment. Field data on

  3. Biocides in hydraulic fracturing: hazard and vulnerability with respect to potential groundwater pollution

    Science.gov (United States)

    Worrall, Fred; Wilson, Miles; Davies, Richard

    2016-04-01

    Biocides are one possible chemical additive to frack fluids and their role is to control bacterial growth. Bacterial growth might lead to biofilm build up; and acid sulfide species and hydrogen sulfide (H2S) production: biofilm build up may reduce formation permeability and hinder gas extraction. Kahrilas et al. (2014) published a review of common biocides used in fracking in the USA. The biocides assessed in the review were the sixteen most commonly used in the USA, based on the hydraulic fracturing chemical registry Frac Focus (Frac Focus, 2015). However, the review of Kahrilas et al. (2014) contained no data or observations and so the objective of this study was to consider whether biocides proposed for use in hydrofacturing could be a threat to English groundwater. The study considered all groundwater samples analysed for biocides in English groundwater between 2005 and 2014. The monitoring records were compared to: records of application (both amount and area); and chemical and molecular data for the biocides. The study did not use traditional adsorption and degradation data as these parameters are to prone to variability and are not pure molecular parameters. The study then used the approach of Worrall and Thomsen (2004) to consider the hazard represented by proposed frack biocides and the approach of Worrall and Kolpin (2003) to consider the vulnerability of the areas of potential shale gas exploitation. The study showed that of the 113 biocides tested for in English groundwaters in the decade 2005 - 2014 that 95 were detected above 0.1 g/l . Of these 95, 41 were compounds that were not recorded as being applied during the period of record and the detection of these 41 compounds did not decline over the 10 year period which implies very long residence times and that once compounds do pollute an aquifer then they will be a persistent problem. Furthermore, the solubility of the range of biocides used in frack fluids would imply a potentially higher hazard

  4. Study of Ground water Groundwater Potentiality and Sea Water Intrusion Along along the Coastal Plain, Wadi Thuwal, KSA- A Case Study Based on DC Resistivity

    Directory of Open Access Journals (Sweden)

    Mansour A. Al-Garni

    2010-12-01

    Full Text Available The present study mainly aims to outline zones that have groundwater potentiality with good quality and those which are affected by sea water intrusion. The electrical resistivity data were acquired over an area of about 170 km2 of a coastal plain, Wadi Thuwal, which is bounded by the Red Sea in the west and the volcanic hills in the east.  In such an area, resistivity measurements, using n-layering model, reveal generally reveal a wide range of resistivity values which do not reflect the reality. Hence, the statistical analysis has to be involved to overcome this problem and to make the final interpretation reliable.  In our case, the n-layer models were modified to another statistical geoelectric models (SLM, consisting of  a number of layers equivalent to the stratigraphic layering beneath each VES site. The modified models were used to outline the depth to the bed rock, groundwater accumulation zones and  water table as well as to define the effect of sea water intrusion through the study area. Check alignment above

  5. Measurements of HFC-134a and HCFC-22 in groundwater and unsaturated-zone air: implications for HFCs and HCFCs as dating tracers

    Science.gov (United States)

    Haase, Karl B.; Busenberg, Eurybiades; Plummer, Niel; Casile, Gerolamo; Sanford, Ward E.

    2014-01-01

    A new analytical method using gas chromatography with an atomic emission detector (GC–AED) was developed for measurement of ambient concentrations of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in soil, air, and groundwater, with the goal of determining their utility as groundwater age tracers. The analytical detection limits of HCFC-22 (difluorochloromethane, CHClF2) and HFC-134a (1,2,2,2-tetrafluoroethane, C2H2F4) in 1 L groundwater samples are 4.3 × 10− 1 and 2.1 × 10− 1 pmol kg− 1, respectively, corresponding to equilibrium gas-phase mixing ratios of approximately 5–6 parts per trillion by volume (pptv). Under optimal conditions, post-1960 (HCFC-22) and post-1995 (HFC-134a) recharge could be identified using these tracers in stable, unmixed groundwater samples. Ambient concentrations of HCFC-22 and HFC-134a were measured in 50 groundwater samples from 27 locations in northern and western parts of Virginia, Tennessee, and North Carolina (USA), and 3 unsaturated-zone profiles were collected in northern Virginia. Mixing ratios of both HCFC-22 and HFC-134a decrease with depth in unsaturated-zone gas profiles with an accompanying increase in CO2 and loss of O2. Apparently, ambient concentrations of HCFC-22 and HFC-134a are readily consumed by methanotrophic bacteria under aerobic conditions in the unsaturated zone. The results of this study indicate that soils are a sink for these two greenhouse gases. These observations contradict the previously reported results from microcosm experiments that found that degradation was limited above-ambient HFC-134a. The groundwater HFC and HCFC concentrations were compared with concentrations of chlorofluorocarbons (CFCs, CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6). Nearly all samples had measured HCFC-22 or HFC-134a that were below concentrations predicted by the CFCs and SF6, with many samples showing a complete loss of HCFC-22 and HFC-134a. This study indicates that HCFC-22 and HFC-134

  6. On the use of mean groundwater age, life expectancy and capture probability for defining aquifer vulnerability and time-of-travel zones for source water protection.

    Science.gov (United States)

    Molson, J W; Frind, E O

    2012-01-01

    Protection and sustainability of water supply wells requires the assessment of vulnerability to contamination and the delineation of well capture zones. Capture zones, or more generally, time-of-travel zones corresponding to specific contaminant travel times, are most commonly delineated using advective particle tracking. More recently, the capture probability approach has been used in which a probability of capture of P=1 is assigned to the well and the growth of a probability-of-capture plume is tracked backward in time using an advective-dispersive transport model. This approach accounts for uncertainty due to local-scale heterogeneities through the use of macrodispersion. In this paper, we develop an alternative approach to capture zone delineation by applying the concept of mean life expectancy E (time remaining before being captured by the well), and we show how life expectancy E is related to capture probability P. Either approach can be used to delineate time-of-travel zones corresponding to specific travel times, as well as the ultimate capture zone. The related concept of mean groundwater age A (time since recharge) can also be applied in the context of defining the vulnerability of a pumped aquifer. In the same way as capture probability, mean life expectancy and groundwater age account for local-scale uncertainty or unresolved heterogeneities through macrodispersion, which standard particle tracking neglects. The approach is tested on 2D and 3D idealized systems, as well as on several watershed-scale well fields within the Regional Municipality of Waterloo, Ontario, Canada. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Evolution of chemical and isotopic composition of inorganic carbon in a complex semi-arid zone environment: Consequences for groundwater dating using radiocarbon

    Science.gov (United States)

    Meredith, K. T.; Han, L. F.; Hollins, S. E.; Cendón, D. I.; Jacobsen, G. E.; Baker, A.

    2016-09-01

    Estimating groundwater age is important for any groundwater resource assessment and radiocarbon (14C) dating of dissolved inorganic carbon (DIC) can provide this information. In semi-arid zone (i.e. water-limited environments), there are a multitude of reasons why 14C dating of groundwater and traditional correction models may not be directly transferable. Some include; (1) the complex hydrological responses of these systems that lead to a mixture of different ages in the aquifer(s), (2) the varied sources, origins and ages of organic matter in the unsaturated zone and (3) high evaporation rates. These all influence the evolution of DIC and are not easily accounted for in traditional correction models. In this study, we determined carbon isotope data for; DIC in water, carbonate minerals in the sediments, sediment organic matter, soil gas CO2 from the unsaturated zone, and vegetation samples. The samples were collected after an extended drought, and again after a flood event, to capture the evolution of DIC after varying hydrological regimes. A graphical method (Han et al., 2012) was applied for interpretation of the carbon geochemical and isotopic data. Simple forward mass-balance modelling was carried out on key geochemical processes involving carbon and agreed well with observed data. High values of DIC and δ13CDIC, and low 14CDIC could not be explained by a simple carbonate mineral-CO2 gas dissolution process. Instead it is suggested that during extended drought, water-sediment interaction leads to ion exchange processes within the top ∼10-20 m of the aquifer which promotes greater calcite dissolution in saline groundwater. This process was found to contribute more than half of the DIC, which is from a mostly 'dead' carbon source. DIC is also influenced by carbon exchange between DIC in water and carbonate minerals found in the top 2 m of the unsaturated zone. This process occurs because of repeated dissolution/precipitation of carbonate that is dependent on

  8. An update of hydrologic conditions and distribution of selected constituents in water, eastern Snake River Plain aquifer and perched groundwater zones, Idaho National Laboratory, Idaho, emphasis 2012-15

    Science.gov (United States)

    Bartholomay, Roy C.; Maimer, Neil V.; Rattray, Gordon W.; Fisher, Jason C.

    2017-04-10

    Since 1952, wastewater discharged to in ltration ponds (also called percolation ponds) and disposal wells at the Idaho National Laboratory (INL) has affected water quality in the eastern Snake River Plain (ESRP) aquifer and perched groundwater zones underlying the INL. The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, maintains groundwater-monitoring networks at the INL to determine hydrologic trends and to delineate the movement of radiochemical and chemical wastes in the aquifer and in perched groundwater zones. This report presents an analysis of water-level and water-quality data collected from the ESRP aquifer, multilevel monitoring system (MLMS) wells in the ESRP aquifer, and perched groundwater wells in the USGS groundwater monitoring networks during 2012-15.

  9. Spatial and temporal variation of nutrients in groundwater and associated processes in the coastal zone of the Pearl River Delta, China

    Science.gov (United States)

    Chen, J.

    2017-12-01

    Rapid urbanization has occurred in the Pearl River Delta since 1980s, resulting in tremendous accumulation of population and material in an area of around 1.1x104 km2. Massive nutrients were released to the coastal zone either via the Pearl River or the aquifer, and effects of these nutrients on ecosystem and drinking water supply are a big public concern. Field campaigns to collect groundwater samples were implemented in rainy (April- September) and dry seasons (October - March) during the period of 2005-2016, and samples were analyzed for major ions, nutrients, multiple isotopes, N2O and microbiological DNA. Seasonal and spatial pattern of nutrients from the recharge to the discharge zone in two case study areas were identified and compared regarding relevant N transformation processes. Main sources of nutrients in groundwater and major mechanisms, e.g. denitrification, nitrification and etc., involved in these processes were raised by integrating microbiological, isotopic and geochemical evidences. Driven forces of the change in nutrients in the past 10 years were investigated based on statistical data, and total nutrient load in groundwater in the delta was estimated.

  10. A comparison between ten advanced and soft computing models for groundwater qanat potential assessment in Iran using R and GIS

    Science.gov (United States)

    Naghibi, Seyed Amir; Pourghasemi, Hamid Reza; Abbaspour, Karim

    2018-02-01

    Considering the unstable condition of water resources in Iran and many other countries in arid and semi-arid regions, groundwater studies are very important. Therefore, the aim of this study is to model groundwater potential by qanat locations as indicators and ten advanced and soft computing models applied to the Beheshtabad Watershed, Iran. Qanat is a man-made underground construction which gathers groundwater from higher altitudes and transmits it to low land areas where it can be used for different purposes. For this purpose, at first, the location of the qanats was detected using extensive field surveys. These qanats were classified into two datasets including training (70%) and validation (30%). Then, 14 influence factors depicting the region's physical, morphological, lithological, and hydrological features were identified to model groundwater potential. Linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), flexible discriminant analysis (FDA), penalized discriminant analysis (PDA), boosted regression tree (BRT), random forest (RF), artificial neural network (ANN), K-nearest neighbor (KNN), multivariate adaptive regression splines (MARS), and support vector machine (SVM) models were applied in R scripts to produce groundwater potential maps. For evaluation of the performance accuracies of the developed models, ROC curve and kappa index were implemented. According to the results, RF had the best performance, followed by SVM and BRT models. Our results showed that qanat locations could be used as a good indicator for groundwater potential. Furthermore, altitude, slope, plan curvature, and profile curvature were found to be the most important influence factors. On the other hand, lithology, land use, and slope aspect were the least significant factors. The methodology in the current study could be used by land use and terrestrial planners and water resource managers to reduce the costs of groundwater resource discovery.

  11. Use of geothermal heat by means of energetic geostructures. Methodology to identify potential zones of application; Exploitation de la chaleur terrestre par des geostructures energetiques. Methodologie de determination des zones potentielles

    Energy Technology Data Exchange (ETDEWEB)

    Joliquin, P.

    2002-07-01

    This study focuses on the realisation of earth heat exchangers by means of so-called geostructures. These geostructures are works of concrete being in close contact with the ground and which are used for foundation or as retaining structures. The three main types of geostructures are piles, the walls and the foundation slabs. These structures can be equipped with a network of tubes where a liquid circulates to permit a heat exchange with the ground. In this case, they can be called energetic geostructures. To date, the use of this technology is rather limited in Switzerland. Therefore, the aim of this study is to increase its development, and a methodology to identify potential zones of application will be given for the purpose of energy planning. The correct land planning and the geotechnical properties of the ground are the two basic criteria to select the type of geostructure and its foundation conditions. Additional criteria like the thermal properties of the ground and the presence of groundwater will determine whether geostructures can be equipped with heat exchangers. Finally, the protection of the groundwater and thermal ground disturbances are possible criteria which could limit the application of energetic geostructures. To validate this methodology, six sites were selected in the canton of Geneva. Two of them ('La Chapelle - Les Sciers' and 'Frontenex - Gradelle'), were investigated by applying the above mentioned criteria. The conclusion is that the two sites represent potential zones for using energetic geostructures. Nevertheless, within the site 'La Chapelle - Les Sciers', the presence of an important groundwater resource was identified. To protect it, it is not permitted to pierce the impermeable layer above the aquifer, and therefore foundation depths must carefully be chosen by controlling the lengths of piles. (author)

  12. Predicting Seawater Intrusion in Coastal Groundwater Boreholes Using Self-Potential Data

    Science.gov (United States)

    Graham, M.; MacAllister, D. J.; Jackson, M.; Vinogradov, J.; Butler, A. P.

    2017-12-01

    Many coastal groundwater abstraction wells are under threat from seawater intrusion: this is exacerbated in summer by low water tables and increased abstraction. Existing hydrochemistry or geophysical techniques often fail to predict the timing of intrusion events. We investigate whether the presence and transport of seawater can influence self-potentials (SPs) measured within groundwater boreholes, with the aim of using SP monitoring to provide early warning of saline intrusion. SP data collection: SP data were collected from a coastal groundwater borehole and an inland borehole (> 60 km from the coast) in the Seaford Chalk of southern England. The SP gradient in the inland borehole was approximately 0.05 mV/m, while that in the coastal borehole varied from 0.16-0.26 mV/m throughout the monitoring period. Spectral analysis showed that semi-diurnal fluctuations in the SP gradient were several orders of magnitude higher at the coast than inland, indicating a strong influence from oceanic tides. A characteristic decrease in the gradient, or precursor, was observed in the coastal borehole several days prior to seawater intrusion. Modelling results: Hydrodynamic transport and geoelectric modelling suggest that observed pressure changes (associated with the streaming potential) are insufficient to explain either the magnitude of the coastal SP gradient or the semi-diurnal SP fluctuations. By contrast, a model of the exclusion-diffusion potential closely matches these observations and produces a precursor similar to that observed in the field. Sensitivity analysis suggests that both a sharp saline front and spatial variations in the exclusion efficiency arising from aquifer heterogeneities are necessary to explain the SP gradient observed in the coastal borehole. The presence of the precursor in the model depends also on the presence and depth of fractures near the base of the borehole. Conclusions: Our results indicate that SP monitoring, combined with hydrodynamic

  13. Appetite for danger - genetic potential for PCP degradation at historically polluted groundwater sites

    Science.gov (United States)

    Mikkonen, Anu; Yläranta, Kati; Tiirola, Marja; Romantschuk, Martin; Sinkkonen, Aki

    2016-04-01

    Pentachlorophenol (PCP) is a priority pollutant of exclusively anthropogenic origin. Formerly used commonly in timber preservatives, PCP has persisted at polluted groundwater sites decades after its use was banned, typically as the last detectable contaminant component. Notorious for its toxicity and poor biodegradability, little is known about the genetic potential and pathways for PCP degradation in the environment. The only fully characterized mineralization pathway is initiated by the enzyme coded by chromosomal pcpB gene, previously detected in PCP degrading Sphingomonadaceae bacteria isolated at two continents. However, there is no information about the abundance or diversity of any PCP degradation related gene at contaminated sites in situ. Our aim was to assess whether pcpB and/or sphingomonads seem to play a role in in situ degradation of PCP, by studying whether pcpB i) is detectable at chlorophenol-polluted groundwater sediments, ii) responds to PCP concentration changes, and iii) shows correlation with the abundance of sphingomonads or a specific sphingomonad genus. Novel protocols for quantification and profiling of pcpB, with primers covering full known diversity, were developed and tested at two sites in Finland with well-documented long-term chlorophenol contamination history: Kärkölä and Pursiala. High throughput sequencing complemented characterization of the total bacterial community and pcpB gene pool. The relative abundance of pcpB in bacterial community was associated with spatial variability in groundwater PCP concentration in Pursiala, and with temporal differences in groundwater PCP concentration in Kärkölä. T-RFLP fingerprinting results indicated and Ion Torrent PGM and Sanger sequencing confirmed the presence of a single phylotype of pcpB at both geographically distant, historically contaminated sites, matching the one detected previously in Canadian bioreactor clones and Kärkölä bioreactor isolates. Sphingomonad abundance

  14. An update of hydrologic conditions and distribution of selected constituents in water, Snake River Plain aquifer and perched groundwater zones, Idaho National Laboratory, Idaho, emphasis 2006-08

    Science.gov (United States)

    Davis, Linda C.

    2010-01-01

    Since 1952, radiochemical and chemical wastewater discharged to infiltration ponds (also called percolation ponds), evaporation ponds, and disposal wells at the Idaho National Laboratory (INL) has affected water quality in the eastern Snake River Plain aquifer and perched groundwater zones underlying the INL. The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, maintains groundwater monitoring networks at the INL to determine hydrologic trends, and to delineate the movement of radiochemical and chemical wastes in the aquifer and in perched groundwater zones. This report presents an analysis of water-level and water-quality data collected from aquifer and perched groundwater wells in the USGS groundwater monitoring networks during 2006-08. Water in the Snake River Plain aquifer primarily moves through fractures and interflow zones in basalt, generally flows southwestward, and eventually discharges at springs along the Snake River. The aquifer primarily is recharged from infiltration of irrigation water, infiltration of streamflow, groundwater inflow from adjoining mountain drainage basins, and infiltration of precipitation. From March-May 2005 to March-May 2008, water levels in wells generally remained constant or rose slightly in the southwestern corner of the INL. Water levels declined in the central and northern parts of the INL. The declines ranged from about 1 to 3 feet in the central part of the INL, to as much as 9 feet in the northern part of the INL. Water levels in perched groundwater wells around the Advanced Test Reactor Complex (ATRC) also declined. Detectable concentrations of radiochemical constituents in water samples from wells in the Snake River Plain aquifer at the INL generally decreased or remained constant during 2006-08. Decreases in concentrations were attributed to decreased rates of radioactive-waste disposal, radioactive decay, changes in waste-disposal methods, and dilution from recharge and underflow. In April

  15. Impact of urbanization on hydrochemical evolution of groundwater and on unsaturated-zone gas composition in the coastal city of Tel Aviv, Israel

    Science.gov (United States)

    Zilberbrand, M.; Rosenthal, E.; Shachnai, E.

    2001-08-01

    The coastal city of Tel Aviv was founded at the beginning of the 20th century. The number of its inhabitants and its water consumption increased rapidly. This study analyses a 15-year record (1934-1948) of pre-industrial development of groundwater chemistry in the urban area. Archive data on concentrations of major ions, dissolved gases (CO 2 and O 2), organic matter, and pH were available for each half-year during the period of 1934-1948. The major factors causing changes in the chemistry of groundwater flowing in three sandy sub-aquifers have been seawater encroachment due to overpumping, and infiltration of effluents from pit-latrine collectors. Influence of these factors decreases with depth. Landward-penetrating seawater passed through clayey coastal sediments, interbedded among sands and calcareous sandstones, and spread into the Kurkar Group aquifer. This has led to exchange of sodium (dominant in seawater) with calcium adsorbed on clay particles, enriching groundwater with calcium. Intensity of cation exchange decreases inland and with depth. Infiltration of pit-latrine effluents has introduced large amounts of ammonium into the unsaturated zone. Its rapid oxidation in unsaturated sediments has caused massive nitrate production, accompanied by pore-water acidification. This process induces dissolution of vadose carbonate, resulting in enrichment of groundwater recharge in calcium. Anthropogenically induced dissolution of calcite in the unsaturated zone has been the major factor for the increase of Ca 2+ concentration in groundwater, accounting for about 80% of this increase. In the interface zone, an additional 20% of calcium has been supplied by cation exchange. Owing to pH increase caused by denitrification in the aquifer, Ca 2+-rich waters supersaturated with calcite could be formed, especially in the capillary fringe of the uppermost sub-aquifer, which could induce calcite precipitation and ultimately lead to the cementation of sandy aquifers. Urban

  16. Nuclear and isotopic techniques for the characterization of submarine groundwater discharge in coastal zones. Results of a coordinated research project 2001-2006

    International Nuclear Information System (INIS)

    2007-07-01

    Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of nearshore waters. These discharges typically display significant spatial and temporal variability, making direct assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise. An initiative on SGD characterization was developed by the IAEA and UNESCO in 2000 as a 5-year plan to assess methodologies and importance of SGD for coastal zone management. The IAEA component included a Coordinated Research Project (CRP) on Nuclear and Isotopic Techniques for the Characterization of Submarine Groundwater Discharge (SGD) in Coastal Zones, carried out jointly by the IAEA's Isotope Hydrology Section in Vienna and the Marine Environment Laboratory in Monaco, together with 9 laboratories from 8 countries. In addition to the IAEA, the Intergovernmental Oceanographic Commission (IOC) and the International Hydrological Programme (IHP) have provided support. This overall effort originally grew from a project sponsored by the Scientific Committee on Ocean Research (SCOR) who established a Working Group (112) on SGD. The activities included joint meetings (Vienna 2000, 2002, and 2005; Syracuse, Italy, 2001; and Monaco 2004), sampling expeditions (Australia 2000; Sicily 2001 and 2002; New York 2002; Brazil 2003; and Mauritius 2005), joint analytical work, data evaluation, and preparation of joint publications. The objectives of the CRP included the improvement of capabilities for water resources and environmental management of coastal zones; application of recently developed nuclear and isotopic techniques suitable for quantitative estimation of various components of SGD; understanding of the influence of SGD on coastal processes and on groundwater

  17. Groundwater movements around a repository

    International Nuclear Information System (INIS)

    Burgess, A.

    1977-10-01

    Based on regional models of groundwater flow, the regional hydraulic gradient at depth is equal to the regional topographic gradient. As a result, the equipotentials are near vertical. The permeability distribution with depth influences the groundwater flow patterns. A zone of sluggish flows, the quiescent zone is developed when the permeability decreases with depth. This feature is accentuated when horizontal anisotropy, with the horizontal permeability higher then the vertical permeability, is included. The presence of an inactive zone will be a prerequesite for a satisfactory repository site. The effect of an inclined discontinuity representing a singular geological feature such as a fault plane or shear zone has been modelled. The quiescent zone does not appear to be unduly disturbed by such a feature. However, meaningful quantitative predictions related to the flows in a typical singular feature cannot be made without more specific data on their hydraulic properties. Two dimensional analysis has been made for a site specific section of a candidate repository site at Forsmark, Sweden. The lateral extent of the model was defined by major tectonic features, assumed vertical. Potential gradients and pore velocities have been computed for a range of boundary conditions and assumed material properties. The potential gradients for the model with anisotropic permeability approach the average potential gradient between the boundaries. The result of this study of the initial groundwater conditions will be used as input data for the analyses of the thermomechanical perturbations of the groundwater regime. In the long term, the groundwater flow will return to the initial conditions. The residual effects of the repository on the flow will be discussed in part 2 of this report. (author)

  18. Abacus to determine soils salinity in presence of saline groundwater in arid zones case of the region of Ouargla

    Science.gov (United States)

    Fergougui, Myriam Marie El; Benyamina, Hind; Boutoutaou, Djamel

    2018-05-01

    In order to remedy the limit of salt intake to the soil surface, it is necessary to study the causes of the soil salinity and find the origin of these salts. The arid areas in the region of Ouargla lie on excessively mineralized groundwater whose level is near the soil surface (0 - 1.5 m). The topography and absence of a reliable drainage system led to the rise of the groundwater beside the arid climatic conditions contributed to the salinization and hydromorphy of the soils. The progress and stabilization of cultures yields in these areas can only occur if the groundwater is maintained (drained) to a depth of 1.6 m. The results of works done to the determination of soil salinity depend mainly on the groundwater's salinity, its depth and the climate.

  19. Balancing practicality and hydrologic realism: a parsimonious approach for simulating rapid groundwater recharge via unsaturated-zone preferential flow

    Science.gov (United States)

    Mirus, Benjamin B.; Nimmo, J.R.

    2013-01-01

    The impact of preferential flow on recharge and contaminant transport poses a considerable challenge to water-resources management. Typical hydrologic models require extensive site characterization, but can underestimate fluxes when preferential flow is significant. A recently developed source-responsive model incorporates film-flow theory with conservation of mass to estimate unsaturated-zone preferential fluxes with readily available data. The term source-responsive describes the sensitivity of preferential flow in response to water availability at the source of input. We present the first rigorous tests of a parsimonious formulation for simulating water table fluctuations using two case studies, both in arid regions with thick unsaturated zones of fractured volcanic rock. Diffuse flow theory cannot adequately capture the observed water table responses at both sites; the source-responsive model is a viable alternative. We treat the active area fraction of preferential flow paths as a scaled function of water inputs at the land surface then calibrate the macropore density to fit observed water table rises. Unlike previous applications, we allow the characteristic film-flow velocity to vary, reflecting the lag time between source and deep water table responses. Analysis of model performance and parameter sensitivity for the two case studies underscores the importance of identifying thresholds for initiation of film flow in unsaturated rocks, and suggests that this parsimonious approach is potentially of great practical value.

  20. Simulations of groundwater flow and particle-tracking analysis in the zone of contribution to a public-supply well in San Antonio, Texas

    Science.gov (United States)

    Lindgren, Richard L.; Houston, Natalie A.; Musgrove, MaryLynn; Fahlquist, Lynne S.; Kauffman, Leon J.

    2011-01-01

    In 2006, a public-supply well in San Antonio, Texas, was selected for intensive study to assess the vulnerability of public-supply wells in the Edwards aquifer to contamination by a variety of compounds. A local-scale, steady-state, three-dimensional numerical groundwater-flow model was developed and used in this study to evaluate the movement of water and solutes from recharge areas to the selected public-supply well. Particle tracking was used to compute flow paths and advective traveltimes throughout the model area and to delineate the areas contributing recharge and zone of contribution for the selected public-supply well.

  1. Redox Zonation and Oscillation in the Hyporheic Zone of the Ganges-Brahmaputra-Meghna Delta: Implications for the Fate of Groundwater Arsenic during Discharge

    Science.gov (United States)

    Jung, Hun Bok; Zheng, Yan; Rahman, Mohammad W.; Rahman, Mohammad M.; Ahmed, Kazi M.

    2015-01-01

    Riverbank sediment cores and pore waters, shallow well waters, seepage waters and river waters were collected along the Meghna Riverbank in Gazaria Upazila, Bangladesh in Jan. 2006 and Oct.-Nov. 2007 to investigate hydrogeochemical processes controlling the fate of groundwater As during discharge. Redox transition zones from suboxic (0-2 m depth) to reducing (2-5 m depth) then suboxic conditions (5-7 m depth) exist at sites with sandy surficial deposits, as evidenced by depth profiles of pore water (n=7) and sediment (n=11; diffuse reflectance, Fe(III)/Fe ratios and Fe(III) concentrations). The sediment As enrichment zone (up to ~700 mg kg−1) is associated with the suboxic zones mostly between 0-2 m depth and less frequently between 5-7 m depth. The As enriched zones consist of several 5 to 10 cm-thick dispersed layers and span a length of ~5-15 m horizontally from the river shore. Depth profiles of riverbank pore water deployed along a 32 m transect perpendicular to the river shore show elevated levels of dissolved Fe (11.6±11.7 mg L−1) and As (118±91 μg L−1, mostly as arsenite) between 2-5 m depth, but lower concentrations between 0-2 m depth (0.13±0.19 mg L−1 Fe, 1±1 μg L−1 As) and between 5-6 m depth (1.14±0.45 mg L−1 Fe, 28±17 μg L−1 As). Because it would take more than a few hundred years of steady groundwater discharge (~10 m yr−1) to accumulate hundreds of mg kg−1 of As in the riverbank sediment, it is concluded that groundwater As must have been naturally elevated prior to anthropogenic pumping of the aquifer since the 1970s. Not only does this lend unequivocal support to the argument that As occurrence in the Ganges-Brahmaputra-Meghna Delta groundwater is of geogenic origin, it also calls attention to the fate of this As enriched sediment as it may recycle As into the aquifer. PMID:26855475

  2. Potential groundwater recharge for the State of Minnesota using the Soil-Water-Balance model, 1996-2010

    Science.gov (United States)

    Smith, Erik A.; Westenbroek, Stephen M.

    2015-01-01

    Groundwater recharge is one of the most difficult components of a water budget to ascertain, yet is an important boundary condition necessary for the quantification of water resources. In Minnesota, improved estimates of recharge are necessary because approximately 75 percent of drinking water and 90 percent of agricultural irrigation water in Minnesota are supplied from groundwater. The water that is withdrawn must be supplied by some combination of (1) increased recharge, (2) decreased discharge to streams, lakes, and other surface-water bodies, and (3) removal of water that was stored in the system. Recent pressure on groundwater resources has highlighted the need to provide more accurate recharge estimates for various tools that can assess the sustainability of long-term water use. As part of this effort, the U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency, used the Soil-Water-Balance model to calculate gridded estimates of potential groundwater recharge across Minnesota for 1996‒2010 at a 1-kilometer (0.621-mile) resolution. The potential groundwater recharge estimates calculated for Minnesota from the Soil-Water Balance model included gridded values (1-kilometer resolution) of annual mean estimates (that is, the means for individual years from 1996 through 2010) and mean annual estimates (that is, the mean for the 15-year period 1996−2010).

  3. Use and groundwater risk potential of additives in heat transfer fluids for borehole heat exchangers

    International Nuclear Information System (INIS)

    Ilieva, Dafina

    2014-01-01

    Ground based heat exchanger systems need to be evaluated in terms of potential effects on groundwater quality due to the risk of leakage of borehole heat exchanger fluids. The aim of this work was to identify the compounds which are present in additive mixtures and to investigate experimentally their biodegradability and effects on the biodegradation of the major organic component in borehole heat exchanger fluids. A data survey was carried out in cooperation with the State Ministry of the Environment Baden-Wuerttemberg, Germany to collect detailed information about the identity and application amounts of additives in borehole heat exchanger fluids. The survey revealed that numerous additives of various chemical classes and properties are used as corrosion inhibitors, alkalis, dyes, organic solvents, flavors, defoamers and surfactants. Furthermore, it was shown that glycols are among the most often applied antifreeze agents, the main component of the heat exchanger fluids. Based on the prioritization criteria (i) abundance in the borehole heat exchanger fluids, (ii) persistence, and (iii) mobility in the subsurface, the additives benzotriazole, tolyltriazole, 2-ethylhexanoate, benzoate and decane dicarboxylate were selected for further biodegradation experiments. The biodegradation experiments were carried out in batch systems with 60- or 70-m-deep sediments (sandstone or marl) as inoculum. The samples were taken during the installation of borehole heat exchanger systems at two different sites. The microcosms were conducted under oxic, denitrifying, iron- and sulfate-reducing as well as fermentative conditions at the presumed aquifer temperature of 12 C. The major component ethylene glycol was degraded under all conditions studied. The fastest biodegradation occurred under oxic and nitrate-reducing conditions (< 15 days). In all anoxic, nitrate free experiments with marl-sediment fermentation was the predominant process involved in the biodegradation of ethylene

  4. REMOVAL OF ADDED NITRATE IN COTTON BURR COMPOST, MULCH COMPOST, AND PEAT: MECHANISMS AND POTENTIAL USE FOR GROUNDWATER NITRATE REMEDIATION

    Science.gov (United States)

    We conducted batch tests on the nature and kinetics of removal of added nitrate in cotton burr compost, mulch compost, and sphagnum peat that may be potentially used in a permeable reactive barrier (PRB) for groundwater nitrate remediation. A rigorous steam autoclaving protocol (...

  5. Prediction of contamination potential of groundwater arsenic in Cambodia, Laos, and Thailand using artificial neural network

    Science.gov (United States)

    The arsenic (As) contamination of groundwater has increasingly been recognized as a major global issue of concern. As groundwater resources are one of most important freshwater sources for water supplies in Southeast Asian countries, it is important to investigate the spatial distribution of As cont...

  6. Identification of nitrate sources in groundwater and potential impact on drinking water reservoir (Goczałkowice reservoir, Poland)

    Science.gov (United States)

    Czekaj, Joanna; Jakóbczyk-Karpierz, Sabina; Rubin, Hanna; Sitek, Sławomir; Witkowski, Andrzej J.

    2016-08-01

    Goczałkowice dammed reservoir (area - 26 km2) is a strategic object for flood control in the Upper Vistula River catchment and one of the most important source of drinking water in the Upper Silesian Industrial Region (Southern Poland). Main aims of the investigation were identification of sources of nitrate and assessment of their significance in potential risk to groundwater quality. In the catchment area monitoring network of 22 piezometers, included 14 nested, have been installed. The significant spatial and seasonal differences in chemical composition between northern and southern part of the catchment were indicated based on the groundwater sampling conducted twice - in autumn 2011 and spring 2012. Maximum observed concentrations of nitrate were identified in northern part of the study area 255 mg/L as a results of inappropriate sewage management and agriculture activity. Results, based on the combines multi-scale hydrogeological and hydrochemical field studies, groundwater flow and transport modelling, dual stable isotope approach and geochemical modelling indicate mainly agriculture and inappropriate sewage water management as a sources of NO3- contamination of groundwater which moreover is affected by geochemical processes. In general, contaminated groundwater does not impact surface water quality. However, due to high concentration of nitrate in northern part a continues measurements of nitrogen compounds should be continued and used for reducing uncertainty of the predictive scenarios of the mass transport modelling in the study area.

  7. Water management of the uranium production facility in Brazil (Caetite, BA): potential impacts over groundwater quality

    International Nuclear Information System (INIS)

    Lamego, Fernando; Santos, Robson Rodger; Silva, L. Ferreira da; Fernandes, Horst Monken

    2008-01-01

    The uranium unit of Caetite - in charge of all the 'yellow cake' produced in Brazil - is located in the semi-arid Northeast region at Bahia State. The geological uranium content of the ore is 3000 ppm, which is mainly associated with albite (NaAlSi 8 O 8 ), and its extraction is achieved by means of a Heap-Leach process. This process has a low water demand, which is supplied by a network of wells, but can contribute to change the groundwater quality and in some cases the extinguishing of wells was observed. The managing of liquid mining wastes formed by drainage waters from mine pit and solid waste piles is not enough to avoid unwarranted releases in the environment, which turn necessary the waste treatment through passing them into the industrial plant in order to reduce radionuclide concentrations. The groundwater is Na-HCO 3 type water and relative high concentration of Cl are observed in some groundwater. It seems that levels of uranium in groundwaters are mainly a consequence of the complexation of the metal by carbonates (or other anions) and not by any sort of the contamination of these waters by the drainage accumulated in the open pit. The speciation modelling allows identifying some areas where the replenishment of the aquifer is more active, but in general the recharge is a fast process run by direct infiltration. The stable isotope data (δ 2 H and δ 18 O) showed that evaporation plays a role during the infiltration, causing the groundwater salinization. These data discard the possibility that groundwater salinization was caused by discharge of deeper saline groundwater through faults associated to a regional groundwater flow system. The presence of an active shallow groundwater flow system offers better possibility for sustainable use of the groundwater resources in this semi-arid region of Brazil. (author)

  8. Potential hydrologic changes in the Amazon by the end of the 21st century and the groundwater buffer

    International Nuclear Information System (INIS)

    Pokhrel, Yadu N; Fan, Ying; Miguez-Macho, Gonzalo

    2014-01-01

    This study contributes to the discussions on the future of the Amazon rainforest under a projected warmer-drier climate from the perspectives of land hydrology. Using IPCC HadGEM2-ES simulations of the present and future Amazon climate to drive a land hydrology model that accounts for groundwater constraint on land drainage, we assess potential hydrologic changes in soil water, evapotranspiration (ET), water table depth, and river discharge, assuming unchanged vegetation. We ask: how will ET regimes shift at the end of the 21st century, and will the groundwater help buffer the anticipated water stress in some places-times? We conducted four 10 yr model simulations, at the end of 20th and 21st century, with and without the groundwater. Our model results suggest that, first, over the western and central Amazon, ET will increase due to increased potential evapotranspiration (PET) with warmer temperatures, despite a decrease in soil water; that is, ET will remain PET or atmospheric demand-limited. Second, in the eastern Amazon dry season, ET will decrease in response to decreasing soil water, despite increasing PET demand; that is, ET in these regions-seasons will remain or become more soil water or supply-limited. Third, the area of water-limited regions will likely expand in the eastern Amazonia, with the dry season, as indicated by soil water store, even drier and longer. Fourth, river discharge will be significantly reduced over the entire Amazon but particularly so in the southeastern Amazon. By contrasting model results with and without the groundwater, we found that the slow soil drainage constrained by shallow groundwater can buffer soil water stress, particularly in southeastern Amazon dry season. Our model suggests that, if groundwater buffering effect is accounted for, the future Amazon water stress may be less than that projected by most climate models. (letter)

  9. Assessment of potential impacts of major groundwater contaminants to fall chinook salmon (Oncorhynchus tshawytscha) in the Hanford Reach, Columbia River

    International Nuclear Information System (INIS)

    Geist, D.R.; Poston, T.M.; Dauble, D.D.

    1994-10-01

    Past operations of Hanford Site facilities have contaminated the groundwater adjacent to the Hanford Reach of the Columbia River, Washington, with various chemical and radiological constituents. The groundwater is hydraulically connected to the river and contains concentrations of contaminants that sometimes exceed federal and/or state drinking water standards or standards for the protection of aquatic life. For example, concentrations of chromium in shoreline seeps and springs at most 100 Area operable units exceed concentrations found to be toxic to fish. Nitrate and tritium concentrations in shoreline seeps are generally below drinking water standards and concentrations potentially toxic to aquatic life, but nitrate concentrations may be high enough to synergistically interact with and exacerbate chromium toxicity. The Hanford Reach also supports the largest run of fall chinook salmon (Oncorhynchus tshawytscha) in the Columbia River Basin. Numbers of fall chinook salmon returning to the Hanford Reach have increased relative to other mainstem populations during the last 30 years. Groundwater discharge appears to occur near some salmon spawning areas, but contaminants are generally not detectable in surface water samples. The concentration and potential toxicity of contaminants in the interstitial waters of the substrate where fall chinook salmon embryogenesis occurs are presently unknown. New tools are required to characterize the extent of groundwater contaminant discharge to the Hanford Reach and to resolve uncertainties associated with assessment of potential impacts to fall chinook salmon

  10. Stress state and movement potential of the Kar-e-Bas fault zone, Fars, Iran

    Science.gov (United States)

    Sarkarinejad, Khalil; Zafarmand, Bahareh

    2017-08-01

    The Kar-e-Bas or Mengharak basement-inverted fault is comprised of six segments in the Zagros foreland folded belt of Iran. In the Fars region, this fault zone associated with the Kazerun, Sabz-Pushan and Sarvestan faults serves as a lateral transfer zone that accommodates the change in shortening direction from the western central to the eastern Zagros. This study evaluates the recent tectonic stress regime of the Kar-e-Bas fault zone based on inversion of earthquake focal mechanism data, and quantifies the fault movement potential of this zone based on the relationship between fault geometric characteristics and recent tectonic stress regimes. The trend and plunge of σ 1 and σ 3 are S25°W/04°-N31°E/05° and S65°E/04°-N60°W/10°, respectively, with a stress ratio of Φ = 0.83. These results are consistent with the collision direction of the Afro-Arabian continent and the Iranian microcontinent. The near horizontal plunge of maximum and minimum principle stresses and the value of stress ratio Φ indicate that the state of stress is nearly strike-slip dominated with little relative difference between the value of two principal stresses, σ 1 and σ 2. The obliquity of the maximum compressional stress into the fault trend reveals a typical stress partitioning of thrust and strike-slip motion in the Kar-e-Bas fault zone. Analysis of the movement potential of this fault zone shows that its northern segment has a higher potential of fault activity (0.99). The negligible difference between the fault-plane dips of the segments indicates that their strike is a controlling factor in the changes in movement potential.

  11. A hybrid machine learning model to estimate nitrate contamination of production zone groundwater in the Central Valley, California

    Science.gov (United States)

    Ransom, K.; Nolan, B. T.; Faunt, C. C.; Bell, A.; Gronberg, J.; Traum, J.; Wheeler, D. C.; Rosecrans, C.; Belitz, K.; Eberts, S.; Harter, T.

    2016-12-01

    A hybrid, non-linear, machine learning statistical model was developed within a statistical learning framework to predict nitrate contamination of groundwater to depths of approximately 500 m below ground surface in the Central Valley, California. A database of 213 predictor variables representing well characteristics, historical and current field and county scale nitrogen mass balance, historical and current landuse, oxidation/reduction conditions, groundwater flow, climate, soil characteristics, depth to groundwater, and groundwater age were assigned to over 6,000 private supply and public supply wells measured previously for nitrate and located throughout the study area. The machine learning method, gradient boosting machine (GBM) was used to screen predictor variables and rank them in order of importance in relation to the groundwater nitrate measurements. The top five most important predictor variables included oxidation/reduction characteristics, historical field scale nitrogen mass balance, climate, and depth to 60 year old water. Twenty-two variables were selected for the final model and final model errors for log-transformed hold-out data were R squared of 0.45 and root mean square error (RMSE) of 1.124. Modeled mean groundwater age was tested separately for error improvement in the model and when included decreased model RMSE by 0.5% compared to the same model without age and by 0.20% compared to the model with all 213 variables. 1D and 2D partial plots were examined to determine how variables behave individually and interact in the model. Some variables behaved as expected: log nitrate decreased with increasing probability of anoxic conditions and depth to 60 year old water, generally decreased with increasing natural landuse surrounding wells and increasing mean groundwater age, generally increased with increased minimum depth to high water table and with increased base flow index value. Other variables exhibited much more erratic or noisy behavior in

  12. Hydrogeophysical investigation of groundwater potential and aquifer vulnerability prediction in basement complex terrain – A case study from Akure, Southwestern Nigeria

    Directory of Open Access Journals (Sweden)

    Akinrinade Opeyemi J.

    2016-06-01

    Full Text Available This study provides a model for the prediction of groundwater potential and vulnerability of basement aquifers in parts of Akure, Southwestern Nigeria. Hydrogeophysical surveys involving very-low-frequency electromagnetic (VLF-EM profiling and electrical resistivity (ER sounding, as well as evaluation of hydraulic gradient using three-point method, were carried out. Ten VLF-EM reconnaissance survey traverses, with lengths ranging from 55 m to 75 m, at 10 m station separation, and 12 vertical electrical sounding (VES stations were occupied. Two-dimensional map of the filtered real component reveals areas of high conductivity, indicative of linear features that can serve as a reservoir or conduit for fluid flow. Interpretation of the VES results delineates three to four geoelectric units. Two aquifer zones were identified, with resistivity values in the ranges of 20 Ωm to 310 Ωm and 100 Ωm to 3,000 Ω m, respectively. Transverse resistance, longitudinal conductance, coefficient of anisotropy and hydraulic gradient have values ranging from 318.2 Ωm2 to 1,041.8 Ωm2, 0.11 mhos to 0.39 mhos, 1.04 to 1.74 and 0.017 to 0.05, respectively. The results of this study identified two prospective borehole locations and the optimum position to site the proposed septic system, based on the aquifer’s protective capacity and groundwater flow properties.

  13. Biological productivity and potential resources of the exclusive economic zone (EEZ) of India

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    An assessment of the biological production and the potential fishery resources has been made based on the data collected over a period of 15 years (1976-1991). The entire Exclusive Economic Zone (EEZ), measuring 2.02 million km sup(2) was divided...

  14. Approach for delineation of contributing areas and zones of transport to selected public-supply wells using a regional ground-water flow model, Palm Beach County, Florida

    Science.gov (United States)

    Renken, R.A.; Patterson, R.D.; Orzol, L.L.; Dixon, Joann

    2001-01-01

    Rapid urban development and population growth in Palm Beach County, Florida, have been accompanied with the need for additional freshwater withdrawals from the surficial aquifer system. To maintain water quality, County officials protect capture areas and determine zones of transport of municipal supply wells. A multistep process was used to help automate the delineation of wellhead protection areas. A modular ground-water flow model (MODFLOW) Telescopic Mesh Refinement program (MODTMR) was used to construct an embedded flow model and combined with particle tracking to delineate zones of transport to supply wells; model output was coupled with a geographic information system. An embedded flow MODFLOW model was constructed using input and output file data from a preexisting three-dimensional, calibrated model of the surficial aquifer system. Three graphical user interfaces for use with the geographic information software, ArcView, were developed to enhance the telescopic mesh refinement process. These interfaces include AvMODTMR for use with MODTMR; AvHDRD to build MODFLOW river and drain input files from dynamically segmented linear (canals) data sets; and AvWELL Refiner, an interface designed to examine and convert well coverage spatial data layers to a MODFLOW Well package input file. MODPATH (the U.S. Geological Survey particle-tracking postprocessing program) and MODTOOLS (the set of U.S. Geological Survey computer programs to translate MODFLOW and MODPATH output to a geographic information system) were used to map zones of transport. A steady-state, five-layer model of the Boca Raton area was created using the telescopic mesh refinement process and calibrated to average conditions during January 1989 to June 1990. A sensitivity analysis of various model parameters indicates that the model is most sensitive to changes in recharge rates, hydraulic conductivity for layer 1, and leakance for layers 3 and 4 (Biscayne aquifer). Recharge (58 percent); river (canal

  15. Numerical simulation of groundwater flow, resource optimization, and potential effects of prolonged drought for the Citizen Potawatomi Nation Tribal Jurisdictional Area, central Oklahoma

    Science.gov (United States)

    Ryter, Derek W.; Kunkel, Christopher D.; Peterson, Steven M.; Traylor, Jonathan P.

    2015-08-13

    A hydrogeological study including two numerical groundwater-flow models was completed for the Citizen Potawatomi Nation Tribal Jurisdictional Area of central Oklahoma. One numerical groundwater-flow model, the Citizen Potawatomi Nation model, encompassed the jurisdictional area and was based on the results of a regional-scale hydrogeological study and numerical groundwater flow model of the Central Oklahoma aquifer, which had a geographic extent that included the Citizen Potawatomi Nation Tribal Jurisdictional Area. The Citizen Potawatomi Nation numerical groundwater-flow model included alluvial aquifers not in the original model and improved calibration using automated parameter-estimation techniques. The Citizen Potawatomi Nation numerical groundwater-flow model was used to analyze the groundwater-flow system and the effects of drought on the volume of groundwater in storage and streamflow in the North Canadian River. A more detailed, local-scale inset model was constructed from the Citizen Potawatomi Nation model to estimate available groundwater resources for two Citizen Potawatomi Nation economic development zones near the North Canadian River, the geothermal supply area and the Iron Horse Industrial Park.

  16. ECO Update / Groundwater Foum Issue Paper: Evaluating Ground-Water/Surface-Water Transition Zones in Ecological Risk Assessments

    Science.gov (United States)

    This ECO Update builds on the standard approach to ERA (U.S. EPA 1997), by providing a framework for incorporating groundwater/surface-water (GW/SW) interactions into existing ERAs (see U.S. EPA 1997 and 2001a for an introduction to ecological risk....

  17. Dissolved radon and uranium in groundwater in a potential coal seam gas development region (Richmond River Catchment, Australia).

    Science.gov (United States)

    Atkins, Marnie L; Santos, Isaac R; Perkins, Anita; Maher, Damien T

    2016-04-01

    The extraction of unconventional gas resources such as shale and coal seam gas (CSG) is rapidly expanding globally and often prevents the opportunity for comprehensive baseline groundwater investigations prior to drilling. Unconventional gas extraction often targets geological layers with high naturally occurring radioactive materials (NORM) and extraction practices may possibly mobilise radionuclides into regional and local drinking water resources. Here, we establish baseline groundwater radon and uranium levels in shallow aquifers overlying a potential CSG target formation in the Richmond River Catchment, Australia. A total of 91 groundwater samples from six different geological units showed highly variable radon activities (0.14-20.33 Bq/L) and uranium levels (0.001-2.77 μg/L) which were well below the Australian Drinking Water Guideline values (radon; 100 Bq/L and uranium; 17 μg/L). Therefore, from a radon and uranium perspective, the regional groundwater does not pose health risks to consumers. Uranium could not explain the distribution of radon in groundwater. Relatively high radon activities (7.88 ± 0.83 Bq/L) in the fractured Lismore Basalt aquifer coincided with very low uranium concentrations (0.04 ± 0.02 μg/L). In the Quaternary Sediments aquifers, a positive correlation between U and HCO3(-) (r(2) = 0.49, p uranium was present as uranyl-carbonate complexes. Since NORM are often enriched in target geological formations containing unconventional gas, establishing radon and uranium concentrations in overlying aquifers comprises an important component of baseline groundwater investigations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Potential occurrence of MTBE and BTEX in groundwater resources of Amman-Zarqa basin, Jordan

    International Nuclear Information System (INIS)

    Al Kuisi, Mustafa; Saffarini, Ghazi; Yaseen, Najal; Alawi, Mahmoud

    2012-01-01

    This study investigates potential occurrence, distribution, and sources of the newly added gasoline oxygenate, methyl-tert-butyl ether (MTBE) and the petroleum derivatives benzene, toluene, ethylbenzene, and xylenes called collectively, BTEX, in Jordan's heavily populated Amman-Zarqa Basin (AZB). It presents the first data on the levels of MTBE and BTEX in the aquifers of this basin. One hundred and seventy-nine (179) groundwater wells were sampled near petrol service stations, oil refinery storage tanks, car wrecks, bus stations, and chemical industries at different locations in the basin. Headspace GC and purge and trap GC-MS were utilized to determine the target substances in the samples. Concentrations of BTEX varied between no-detection (minimum) for all of them to 6.6 μg/L (maximum) for ethylbenzene. MTBE was found in few samples but none has exceeded the regulated levels; its concentrations ranged between no-detection to 4.1 μg/L. However, though the contamination levels are very low they should be considered alarming. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. A Field Method For Determination of Groundwater and Groundwater-sediment Associated Potentials for Degradation of Xenobiotic Organic Compounds

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund; Holm, Peter Engelund

    1992-01-01

    Determination of the degradation potentials for a mixture of eight organic trace contaminants (benzene, toluene, o-xylene, naphthalene, tetrachloromethane, 1,1,1-trichloroethane, trichloroethene, tetrachloroethene) has been made by specially developed in situ microcosms under aerobic and anaerobi...

  20. Assessment of Natural Ventilation Potential for Residential Buildings across Different Climate Zones in Australia

    Directory of Open Access Journals (Sweden)

    Zijing Tan

    2017-09-01

    Full Text Available In this study, the natural ventilation potential of residential buildings was numerically investigated based on a typical single-story house in the three most populous climate zones in Australia. Simulations using the commercial simulation software TRNSYS (Transient System Simulation Tool were performed for all seasons in three representative cities, i.e., Darwin for the hot humid summer and warm winter zone, Sydney for the mild temperate zone, and Melbourne for the cool temperate zone. A natural ventilation control strategy was generated by the rule-based decision-tree method based on the local climates. Natural ventilation hour (NVH and satisfied natural ventilation hour (SNVH were employed to evaluate the potential of natural ventilation in each city considering local climate and local indoor thermal comfort requirements, respectively. The numerical results revealed that natural ventilation potential was related to the local climate. The greatest natural ventilation potential for the case study building was observed in Darwin with an annual 4141 SNVH out of 4728 NVH, while the least natural ventilation potential was found in the Melbourne case. Moreover, summer and transition seasons (spring and autumn were found to be the optimal periods to sustain indoor thermal comfort by utilising natural ventilation in Sydney and Melbourne. By contrast, natural ventilation was found applicable over the whole year in Darwin. In addition, the indoor operative temperature results demonstrated that indoor thermal comfort can be maintained only by utilising natural ventilation for all cases during the whole year, except for the non-natural ventilation periods in summer in Darwin and winter in Melbourne. These findings could improve the understanding of natural ventilation potential in different climates, and are beneficial for the climate-conscious design of residential buildings in Australia.

  1. Application of InSAR and gravimetric surveys for developing construction codes in zones of land subsidence induced by groundwater extraction: case study of Aguascalientes, Mexico

    Directory of Open Access Journals (Sweden)

    J. Pacheco-Martínez

    2015-11-01

    Full Text Available Interferometric Synthetic Aperture Radar (InSAR has become a valuable tool for surface deformation monitoring, including land subsidence associated with groundwater extraction. Another useful tools for studying Earth's surface processes are geophysical methods such as Gravimetry. In this work we present the application of InSAR analysis and gravimetric surveying to generate valuable information for risk management related to land subsidence and surface faulting. Subsidence of the city of Aguascalientes, Mexico is presented as study case. Aguascalientes local governments have addressed land subsidence issues by including new requirements for new constructions projects in the State Urban Construction Code. Nevertheless, the resulting zoning proposed in the code is still subjective and not clearly defined. Our work based on gravimetric and InSAR surveys is aimed for improving the subsidence hazard zoning proposed in the State Urban Code in a more comprehensive way. The study includes a 2007–2011 ALOS InSAR time-series analysis of the Aguascalientes valley, an interpretation of the compete Bouguer gravimetric anomaly of the Aguascalientes urban area, and the application of time series and gravimetric anomaly maps for improve the subsidence hazard zoning of Aguascalientes City.

  2. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Bjerg, Poul Løgstrup

    2012-01-01

    The impact of source mass depletion on the down-gradient contaminant mass discharge was monitored for a 19-month period as a part of a field demonstration of the ZVI-Clay soil mixing remediation technology. Groundwater samples were collected from conventional monitoring wells (120 samples) and a ...... down-gradient contaminant mass discharge reduction (76%) for the parent compound (PCE), while the overall reduction of chlorinated ethenes was smaller (21%)....

  3. Seismicity, groundwater level variations and Earth tides in the Hronov-Poříčí Fault Zone, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Kolínský, Petr; Valenta, Jan; Gaždová, Renata

    2012-01-01

    Roč. 9, č. 2 (2012), s. 191-209 ISSN 1214-9705 R&D Projects: GA ČR GA205/09/1244 Institutional research plan: CEZ:AV0Z30460519 Keywords : Eastern Bohemian Massif * groundwater level * seismic ity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_02/9_Kolinsky.pdf

  4. An Isotopic View of Water and Nitrate Transport Through the Vadose Zone in Oregon’s Southern Willamette Valley’s Groundwater Management Area (S-GWMA)

    Science.gov (United States)

    Groundwater nitrate contamination affects thousands of households in Oregon’s southern Willamette Valley and many more across the USA. The southern Willamette Valley Groundwater Management Area (GWMA) was established in 2004 due to nitrate levels in the groundwater exceedi...

  5. Evaluating the role of soil variability on groundwater pollution and recharge at regional scale by integrating a process-based vadose zone model in a stochastic approach

    Science.gov (United States)

    Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna; Lamaddalena, Nicola; Zdruli, Pandi

    2013-04-01

    Interpreting and predicting the evolution of water resources and soils at regional scale are continuing challenges for natural scientists. Examples include non-point source (NPS) pollution of soil and surface and subsurface water from agricultural chemicals and pathogens, as well as overexploitation of groundwater resources. The presence and build up of NPS pollutants may be harmful for both soil and groundwater resources. The accumulation of salts and trace elements in soils can significantly impact crop productivity, while loading of salts, nitrates, trace elements and pesticides into groundwater supplies can deteriorate a source of drinking and irrigation water. Consequently, predicting the spatial distribution and fate of NPS pollutants in soils at applicative scales is now considered crucial for maintaining the fragile balance between crop productivity and the negative environmental impacts of NPS pollutants, which is a basis of sustainable agriculture. Soil scientists and hydrologists are regularly asked to assist state agencies to understand these critical environmental issues. The most frequent inquiries are related to the development of mathematical models needed for analyzing the impacts of alternative land-use and best management use and management of soil and water resources. Different modelling solutions exist, mainly differing on the role of the vadose zone and its horizontal and vertical variability in the predictive models. The vadose zone (the region from the soil surface to the groundwater surface) is a complex physical, chemical and biological ecosystem that controls the passage of NPS pollutants from the soil surface where they have been deposited or accumulated due to agricultural activities, to groundwater. Physically based distributed hydrological models require the internal variability of the vadose zone be explored at a variety of scales. The equations describing fluxes and storage of water and solutes in the unsaturated zone used in these

  6. Application Of Electrical Resistivity Imaging Technique And Colloidal Borescope On Groundwater Study At Block 33, Malaysian Nuclear Agency

    International Nuclear Information System (INIS)

    Mohd Muzamil Mohd Hashim; Mohd Abdul Wahab Yusof; Kamarudin Samuding; Nazran Harun; Nurul Fairuz Diyana Baharudin

    2014-01-01

    Electrical resistivity imaging is a geophysical surveying technique that used to obtain two dimensional (2D) subsurface profile. Base on resistivity value, the potential zone that contained groundwater has been identified. A borehole with 100 m depth has been constructed on the groundwater potential zone. Then, a Colloidal Borescope is being used to get the groundwater velocity and direction. From the resistivity profile, a groundwater zone identified at the north and south area of the study site but the actual direction of groundwater system at that area cannot be recognized so that, the colloidal borescope data being used to clarify the actual flow and direction. Combination from this two type of data produced a good result of groundwater direction in this study area. (author)

  7. Pesticide and Water management alternatives to mitigate potential ground-water contamination for selected counties in Utah

    OpenAIRE

    Ehteshami, Majid; Requena, Antonio M.; Peralta, R. C.; Deer, Howard M.; Hill, Robert W.; Ranjha, Ahmad Yar

    1990-01-01

    Production of adequate supplies of food and fiber currently requires that pesticides be used to limit crop losses from insects, pathogens, weeds and other pests. Although pesticides are necessary in today's agriculture, they can be a serious problem if they reach and contaminate ground water, especially in places where drinking water needs are supplied from ground water. The relative reduction of potential ground-water contamination due to agricultural use of pesticides was analyzed for parti...

  8. Integrated experimental and modeling assessment of potential effects of gas leakages on groundwater composition

    Science.gov (United States)

    Berta, Marton; Dethlefsen, Frank; Ebert, Markus; Schäfer, Dirk

    2017-04-01

    Storing renewably produced energy is one of the major challenges for the energy systems of the upcoming decades. Power-to-gas technologies coupled to geological storage of compressed air, methane, and hydrogen offer a comparatively safe and cost-efficient way for large-scale energy storage. However, the stored gases can potentially escape from their geological reservoir and may thus affect protected natural goods such as groundwater. The geochemical reactions responsible for these composition changes are usually investigated separately in experiments and numerical models. Here we present the outcomes of an integrated experimental and modeling approach through the example of a compressed air leakage scenario. A main consequence of the presence of oxygen to be assessed in an aquifer is pyrite oxidation, well known from acid mine drainage sites. However, in contrast to acid mine drainage sites exhibiting unsaturated sediments and fed by meteoric low-carbonate water, aquifers such as in Northern Germany contain a considerable amount of solid and dissolved inorganic carbon species potentially buffering pH changes. High pressure flow-through column experiments representing an intrusion of compressed air into an aquifer were carried out to quantify pyrite oxidation kinetics and to incorporate the observations into a descriptive reaction model. Surface passivation was found to decrease the reactivity of pyrite by more than 90% after a few months of experimental run time. We propose that the carbonate buffer system enables the precipitation of a passivating mineral layer on the pyrite surface reducing the overall reaction rate significantly. Consequently, an established rate law from the literature was extended by a reactive surface passivation term[1]. This improved reaction rate equation was incorporated into a 3D numerical model using OpenGeoSys with parameters representing similarly typical aquifer conditions the experiments had characterized. These boundaries include

  9. Construction of avulsion potential zone model for Kulik River of Barind Tract, India and Bangladesh.

    Science.gov (United States)

    Sarkar, Debabrata; Pal, Swades

    2018-04-21

    Avulsion is a natural fluvial process but considered it as a hazard in the populated region due to the chance of immense failure of lives and properties. So, early warning indicates that the zone of avulsion can facilitate the people living there. About 317 numbers of local and regional historical imprints of channel cutoff along river Kulik claim the need of this work. The present study tried to identify avulsion potential zone (APZ) of Kulik river of Indo-Bangladesh using multi-parametric weighted combination approach. Analytic hierarchy approach (AHP) is applied for weighting the used parameters. Avulsion potential model clearly exhibits that 9.51-km stream segment of middle and lower catchment is highly susceptible for avulsion especially during sudden high discharge and earthquake incidents. There is also high chance of channel avulsion following the existing Paleo-avulsion courses and left channels. Hard points can also be erected alongside the main channel for resisting channel avulsion propensity.

  10. Determination of dissociation constants of compounds with potential cognition enhancing activity by capillary zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Lišková, A.; Křivánková, Ludmila

    2005-01-01

    Roč. 26, č. 23 (2005), s. 4429-4439 ISSN 0173-0835 R&D Projects: GA ČR GA203/05/2106; GA AV ČR IAA4031401 Institutional research plan: CEZ:AV0Z40310501 Keywords : Capillary zone electrophoresis * dissociation constants * potential nootropics Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.850, year: 2005

  11. Preferential Flow Paths In A Karstified Spring Catchment: A Study Of Fault Zones As Conduits To Rapid Groundwater Flow

    Science.gov (United States)

    Kordilla, J.; Terrell, A. N.; Veltri, M.; Sauter, M.; Schmidt, S.

    2017-12-01

    In this study we model saturated and unsaturated flow in the karstified Weendespring catchment, located within the Leinetal graben in Goettingen, Germany. We employ the finite element COMSOL Multiphysics modeling software to model variably saturated flow using the Richards equation with a van Genuchten type parameterization. As part of the graben structure, the Weende spring catchment is intersected by seven fault zones along the main flow path of the 7400 m cross section of the catchment. As the Weende spring is part of the drinking water supply in Goettingen, it is particularly important to understand the vulnerability of the catchment and effect of fault zones on rapid transport of contaminants. Nitrate signals have been observed at the spring only a few days after the application of fertilizers within the catchment at a distance of approximately 2km. As the underlying layers are known to be highly impermeable, fault zones within the area are likely to create rapid flow paths to the water table and the spring. The model conceptualizes the catchment as containing three hydrogeological limestone units with varying degrees of karstification: the lower Muschelkalk limestone as a highly conductive layer, the middle Muschelkalk as an aquitard, and the upper Muschelkalk as another conductive layer. The fault zones are parameterized based on a combination of field data from quarries, remote sensing and literary data. The fault zone is modeled considering the fracture core as well as the surrounding damage zone with separate, specific hydraulic properties. The 2D conceptual model was implemented in COMSOL to study unsaturated flow at the catchment scale using van Genuchten parameters. The study demonstrates the importance of fault zones for preferential flow within the catchment and its effect on the spatial distribution of vulnerability.

  12. Groundwater circulation and utilisation in an unconfined carbonate system - revealing the potential effect of climate change and humankind activities

    Science.gov (United States)

    Tóth, Ádám; Mádl-Szönyi, Judit

    2016-04-01

    Characteristics of gravitational groundwater flow systems in carbonate regions were presented by Mádl-Szönyi & Tóth (2015) based on theoretical considerations, identification and classification of groundwater flow-related field phenomena and numerical simulation. It was revealed that the changes of flow pattern in carbonate framework attributed to groundwater utilization and/or climate change are more apparent due to the effective hydraulic conductivity of carbonates. Consequently, natural or artificial disturbances of water level propagate farther, deeper and faster in carbonates than in siliciclastic basins. These changes could result in degradation and reorganization of hierarchical flow systems, modification of recharge and discharge areas and even alteration of physicochemical parameters (Mádl-Szönyi & Tóth, 2015). This paper presents the application of the gravity-driven regional groundwater flow concept to the hydrogeologically complex thick carbonate system of the Transdanubian Range, Hungary, depicting the flow pattern of the area and to a practical problem of a local study area, conflicts of interest of water supply and water use of a golf course. The question is how will the natural discharge on the golf course be influenced by the planned karst drinking water production well. In addition, the effects of climate change on this conflict were evaluated. We demonstrate the importance of the understanding the appropriate scale in karst studies and illustrate how the gravity-driven regional groundwater flow concept can help to determine it. For this purpose, the hydrogeological conditions of the study site were examined at different scales. The goals were to define the appropriate scale and reveal the effects of tectonic structures; and give prognoses for the possible impact of a planned drinking water well and climate change on the golf course based on numerical simulation. The study also showed the low geothermal potential of the area.

  13. Trace Metals in Groundwater and the Vadose Zone Calcite: In Situ Containment and Stabilization of Strontium-90 and Other Divalent Metals and Radionuclides at Arid West DOE

    International Nuclear Information System (INIS)

    Smith, Robert W.

    2004-01-01

    Radionuclide and metal contaminants such as strontium-90 are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy. However, implementing in situ containment and stabilization approaches requires definition of the mechanisms that control contaminant sequestration. We are investigating the in situ immobilization of radionuclides or contaminant metals (e.g., strontium-90) by their facilitated co-precipitation with calcium carbonate in groundwater and vadose zone systems. Our facilitated approach, shown schematically in Figure 1, relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity. Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation process tends to be irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from the aqueous phase over the long-term. Another advantage of the ureolysis approach is that the ammonium ions produced by the reaction can exchange with radionuclides sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture in a more stable solid phase (co-precipitation rather than adsorption)

  14. Changes in the Regional Groundwater Aquifer and Potential Impacts on Surface Waters in Central Zealand, Denmark

    DEFF Research Database (Denmark)

    Thorn, Paul

    The regional, confined aquifer on the island of Zealand, in eastern Denmark, is the primary aquifer used for large-scale abstraction for the supplies of all larger cities, including Roskilde and the greater Copenhagen metropolitan area. Large-scale groundwater abstraction from this aquifer...... in the area near Lejre Denmark (approximately 15km to the SW of Roskilde) began in 1937, exporting approximately 18 million m3 of water per year to supply the city of Copenhagen. After abstraction began, streams in the area were observed to go dry after extended periods without precipitation, where......, wetlands and lakes in the area. The results show that there was a significant impact on the regional groundwater aquifer in the Langvad river catchment, with groundwater as much as 17m lower in 1987 from 1936 (pre-abstraction). However, in the Elverdam river catchment, the levels remained virtually...

  15. Analysis of the potential contamination risk of groundwater resources circulating in areas with anthropogenic activities

    Directory of Open Access Journals (Sweden)

    M. Spizzico

    2005-01-01

    Full Text Available The area investigated is located in the province of Brindisi (Italy. It is a generally flat area separated from the nearby carbonatic plateau of the Murgia by quite indistinct and high fault scarps. As regards the geological features, carbonatic basement rocks and post-cretaceous terrains made up of calabrian calcarenites and middle-upper Pleistocenic marine terraced deposits can be distinguished. In the examined area there are two different hydrogeological environments. The first is represented by deep groundwater, the main groundwater resource in Apulia. The second hydrogeological environment, now of lesser importance than the deep aquifer in terms of size and use, is made up of some small shallow groundwater systems situated in post-calabrian sands and located in the eastern area. During some sampling cycles carried out in the studied area, water was withdrawn from both the deep aquifer and from the shallow groundwater. For every sample, the necessary parameters were determined for the physical and chemical characterisation of two different hydrogeological environments. Moreover, some chemical parameters indicating anthropogenic activities were determined. Analysis of the aerial distribution of the measured parameters has shown some main areas subject to different conditions of contamination risk, in accordance with the hydrogeological and geological features of the investigated area. In the south-eastern part of the investigated area, the important action performed by the surface aquifer for protecting the deep groundwater from contamination of anthropogenic origin is clear. On the other hand, in the shallow groundwater, areas of nitrate and nitrite contamination have been identified, which result from the extensive use of fertilizers.

  16. Evaluation Of Groundwater Pathways And Travel Times From The Nevada Test Site To The Potential Yucca Mountain Repository

    International Nuclear Information System (INIS)

    K.F. Pohlman; J. Zhu; M. Ye; J. Chapman; C. Russell; D.S. Shafer

    2006-01-01

    Yucca Mountain (YM), Nevada, has been recommended as a deep geological repository for the disposal of spent fuel and high-level radioactive waste. If YM is licensed as a repository by the Nuclear Regulatory Commission, it will be important to identify the potential for radionuclides to migrate from underground nuclear testing areas located on the Nevada Test Site (NTS) to the hydraulically downgradient repository area to ensure that monitoring does not incorrectly attribute repository failure to radionuclides originating from other sources. In this study, we use the Death Valley Regional Flow System (DVRFS) model developed by the U.S. Geological Survey to investigate potential groundwater migration pathways and associated travel times from the NTS to the proposed YM repository area. Using results from the calibrated DVRFS model and the particle tracking post-processing package MODPATH, we modeled three-dimensional groundwater advective pathways in the NTS and YM region. Our study focuses on evaluating the potential for groundwater pathways between the NTS and YM withdrawal area and whether travel times for advective flow along these pathways coincide with the prospective monitoring timeframe at the proposed repository. We include uncertainty in effective porosity, as this is a critical variable in the determination of time for radionuclides to travel from the NTS region to the YM withdrawal area. Uncertainty in porosity is quantified through evaluation of existing site data and expert judgment and is incorporated in the model through Monte Carlo simulation. Since porosity information is limited for this region, the uncertainty is quite large and this is reflected in the results as a large range in simulated groundwater travel times

  17. Natural colloids in groundwater from granite and their potential impact on radionuclide transport

    International Nuclear Information System (INIS)

    Vilks, P.; Bachinski, D.B.

    1997-03-01

    AECL has submitted an Environmental Impact Statement (EIS) to evaluate the concept of nuclear fuel disposal at depth in crystalline rock of the Canadian Shield. As part of geochemical studies carried out in support of the EIS, the role of natural groundwater colloids (0.001 to 0.45 μm) and suspended particles (>0.45 μm) in radionuclide transport in granite rock has been investigated. This report summarizes the results of investigations carried out in groundwaters from the Whiteshell Research Area (WRA) of southern Manitoba and the Atikokan Research Area (ARA) of northwestern Ontario to determine the concentrations, size distributions, and compositions of natural particles in groundwaters from the Canadian Shield. Particles from groundwater were isolated by ultrafiltration under a nitrogen atmosphere and particle concentrations and size distributions were determined by filtration, and by laser-based particle counting and size analysis. Groundwaters from Canadian Shield granites contain particles in a broad range of sizes, with no one particular size being dominant. Particle compositions include aluminosilicates, Fe oxides, carbonate and organics. Suspended particles are most likely generated by the mobilization of fracture-lining minerals by groundwater flow, while colloids are formed by a combination of precipitation and mobilization of colloidal material from fracture surfaces. The average concentration of 0.01 to 0.45 μm colloids in WRA groundwaters was 1.05 ± 0.14 mg/L. Average colloid concentrations were slightly higher in the more highly fractured ARA, although the highest observed colloid concentration in the ARA was below the 7 mg/L maximum observed in a sample from the WRA. The existence of colloids in the 0.001 to 0.01 μm size range was demonstrated using the results of chemical analysis of particle concentrates and data obtained with the laser-based Ultrafine Particle Size Analyzer (UPA). The WRA groundwaters contain on average about 2.7 mg/L of 0

  18. Concentrations of arsenic and other elements in groundwater of Bangladesh and West Bengal, India: potential cancer risk.

    Science.gov (United States)

    Rahman, Mohammad Mahmudur; Dong, Zhaomin; Naidu, Ravi

    2015-11-01

    We investigated the concentrations of 23 elements in groundwater from arsenic (As) contaminated areas of Bangladesh and West Bengal, India to determine the potential human exposure to metals and metalloids. Elevated concentrations of As was found in all five study areas that exceeded the World Health Organization (WHO) guideline value of 10μg/L. The mean As concentrations in groundwater of Noakhali, Jalangi and Domkal, Dasdia Nonaghata, Deganga and Baruipur were 297μg/L, 262μg/L, 115μg/L, 161μg/L and 349μg/L, respectively. Elevated concentrations of Mn were also detected in all areas with mean concentrations were 139μg/L, 807μg/L, 341μg/L, 579μg/L and 584μg/L for Noakhali, Jalangi and Domkal, Dasdia Nonaghata, Deganga and Baruipur, respectively. Daily As intakes from drinking water for adults and the potential cancer risk for all areas was also estimated. Results suggest that mitigation activities such as water treatment should not only be focused on As but must also consider other elements including Mn, B and Ba. The groundwater used for public drinking purposes needs to be tested periodically for As and other elements to ensure the quality of drinking water is within the prescribed national guidelines. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Methodology for and uses of a radiological source term assessment for potential impacts to stormwater and groundwater

    International Nuclear Information System (INIS)

    Teare, A.; Hansen, K.; DeWilde, J.; Yu, L.; Killey, D.

    2001-01-01

    A Radiological Source Term Assessment (RSTA) was conducted by Ontario Power Generation Inc. (OPG) at the Pickering Nuclear Generating Station (PNGS). Tritium had been identified in the groundwater at several locations under the station, and OPG initiated the RSTA as part of its ongoing efforts to improve operations and to identify potential sources of radionuclide impact to groundwater and stormwater at the station. The RSTA provides a systematic approach to collecting information and assessing environmental risk for radioactive contaminants based on a ranking system developed for the purpose. This paper provides an overview of the RSTA focusing on the investigative approach and how it was applied. This approach can find application at other generating stations. (author)

  20. Numerical groundwater-flow modeling to evaluate potential effects of pumping and recharge: implications for sustainable groundwater management in the Mahanadi delta region, India

    Science.gov (United States)

    Sahoo, Sasmita; Jha, Madan K.

    2017-12-01

    Process-based groundwater models are useful to understand complex aquifer systems and make predictions about their response to hydrological changes. A conceptual model for evaluating responses to environmental changes is presented, considering the hydrogeologic framework, flow processes, aquifer hydraulic properties, boundary conditions, and sources and sinks of the groundwater system. Based on this conceptual model, a quasi-three-dimensional transient groundwater flow model was designed using MODFLOW to simulate the groundwater system of Mahanadi River delta, eastern India. The model was constructed in the context of an upper unconfined aquifer and lower confined aquifer, separated by an aquitard. Hydraulic heads of 13 shallow wells and 11 deep wells were used to calibrate transient groundwater conditions during 1997-2006, followed by validation (2007-2011). The aquifer and aquitard hydraulic properties were obtained by pumping tests and were calibrated along with the rainfall recharge. The statistical and graphical performance indicators suggested a reasonably good simulation of groundwater flow over the study area. Sensitivity analysis revealed that groundwater level is most sensitive to the hydraulic conductivities of both the aquifers, followed by vertical hydraulic conductivity of the confining layer. The calibrated model was then employed to explore groundwater-flow dynamics in response to changes in pumping and recharge conditions. The simulation results indicate that pumping has a substantial effect on the confined aquifer flow regime as compared to the unconfined aquifer. The results and insights from this study have important implications for other regional groundwater modeling studies, especially in multi-layered aquifer systems.

  1. Effects of groundwater withdrawals from the Hurricane Fault zone on discharge of saline water from Pah Tempe Springs, Washington County, Utah

    Science.gov (United States)

    Gardner, Philip M.

    2018-04-10

    Pah Tempe Springs, located in Washington County, Utah, contribute about 95,000 tons of dissolved solids annually along a 1,500-foot gaining reach of the Virgin River. The river gains more than 10 cubic feet per second along the reach as thermal, saline springwater discharges from dozens of orifices located along the riverbed and above the river on both banks. The spring complex discharges from fractured Permian Toroweap Limestone where the river crosses the north-south trending Hurricane Fault. The Bureau of Reclamation Colorado River Basin Salinity Control Program is evaluating the feasibility of capturing and desalinizing the discharge of Pah Tempe Springs to improve downstream water quality in the Virgin River. The most viable plan, identified by the Bureau of Reclamation in early studies, is to capture spring discharge by pumping thermal groundwater from within the Hurricane Fault footwall damage zone and to treat this water prior to returning it to the river.Three multiple-day interference tests were conducted between November 2013 and November 2014, wherein thermal groundwater was pumped from fractured carbonate rock in the fault damage zone at rates of up to 7 cubic feet per second. Pumping periods for these tests lasted approximately 66, 74, and 67 hours, respectively, and the tests occurred with controlled streamflows of approximately 2.0, 3.5, and 24.5 cubic feet per second, respectively, in the Virgin River upstream from the springs reach. Specific conductance, water temperature, and discharge were monitored continuously in the river (upstream and downstream of the springs reach) at selected individual springs, and in the pumping discharge during each of the tests. Water levels were monitored in three observation wells screened in the thermal system. Periodic stream and groundwater samples were analyzed for dissolved-solids concentration and the stable isotopes of oxygen and hydrogen. Additional discrete measurements of field parameters (specific

  2. Potential contribution of groundwater to dry-season ET in the Amazon

    Science.gov (United States)

    Miguez-Macho, Gonzalo; Fan, Ying

    2010-05-01

    Climate and land ecosystem models simulate vegetation stress in the Amazon forest in the dry season, but observations show enhanced growth in response to higher radiation under less cloudy skies indicating an adequate water supply. The question is: how does the vegetation obtain sufficient water, and what is missing in the models? Shallow model soil and rooting depth is a factor; the ability of roots to move water up and down (hydraulic redistribution) may be another, but another cause may lie in the buffering effect of the groundwater found in nature but absent in models. We present observational and modeling evidence that the vast groundwater store, consequence of high annual rainfall combined with poor drainage in the Amazon, may provide a stable source for dry-season photosynthesis. The water table beneath the Amazon is sufficiently shallow (38% area 2mm/day to dry-season evapotranspiration, a non-negligible portion of tower-observed flux of 3-4mm/day, the latter including canopy-interception loss and open-water evaporation. This may have important implications to our understanding of Amazonia ecosystem response and feedback to climate change. Current models, lacking groundwater, predict a significant reduction in dry-season photosynthesis under current climate and large-scale dieback under projected future climate converting the Amazon from a net carbon sink to a net source and accelerating warming. If groundwater is considered in the models, the magnitude of the responses and feedbacks may be reduced.

  3. AGROCLIMATIC ZONING OF EUROPEAN AND ASIAN PEAR CULTIVARS WITH POTENTIAL FOR COMMERCIAL PLANTING IN SOUTHERN BRAZIL

    Directory of Open Access Journals (Sweden)

    MARCOS SILVEIRA WREGE

    Full Text Available ABSTRACT Pear is among the fruits of major commercial interest in the world and one of the most imported in Brazil. Brazilian production is very small and the fruit quality is low, due to production problems. The success of culture in the country, among other factors, may be linked to the choice of cultivars, pollinating and rootstocks better adapted to local conditions, and thus depend on the particulars of an agricultural zoning. The aim of this study was to identify, in southern Brazil, homogeneous climatic zones with potential for growing of European and Asian pears, through climate risk studies. The regions were defined by the seasonal availability of chilling hours (<7.2 °C accumulated during the period from May to September and the monthly risk of drought. The analysis allowed the recognition of four homogeneous areas for the production of pears in southern Brazil.

  4. The Zoning of Forest Fire Potential of Gulestan Province Forests Using Granular Computing and MODIS Images

    Directory of Open Access Journals (Sweden)

    A. Jalilzadeh Shadlouei

    2013-09-01

    Full Text Available There are many vegetation in Iran. This is because of extent of Iran and its width. One of these vegetation is forest vegetation most prevalent in Northern provinces named Guilan, Mazandaran, Gulestan, Ardebil as well as East Azerbaijan. These forests are always threatened by natural forest fires so much so that there have been reports of tens of fires in recent years. Forest fires are one of the major environmental as well as economic, social and security concerns in the world causing much damages. According to climatology, forest fires are one of the important factors in the formation and dispersion of vegetation. Also, regarding the environment, forest fires cause the emission of considerable amounts of greenhouse gases, smoke and dust into the atmosphere which in turn causes the earth temperature to rise up and are unhealthy to humans, animals and vegetation. In agriculture droughts are the usual side effects of these fires. The causes of forest fires could be categorized as either Human or Natural Causes. Naturally, it is impossible to completely contain forest fires; however, areas with high potentials of fire could be designated and analysed to decrease the risk of fires. The zoning of forest fire potential is a multi-criteria problem always accompanied by inherent uncertainty like other multi-criteria problems. So far, various methods and algorithm for zoning hazardous areas via Remote Sensing (RS and Geospatial Information System (GIS have been offered. This paper aims at zoning forest fire potential of Gulestan Province of Iran forests utilizing Remote Sensing, Geospatial Information System, meteorological data, MODIS images and granular computing method. Granular computing is part of granular mathematical and one way of solving multi-criteria problems such forest fire potential zoning supervised by one expert or some experts , and it offers rules for classification with the least inconsistencies. On the basis of the experts’ opinion

  5. Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation.

    Science.gov (United States)

    Dutova, Ekaterina M; Nikitenkov, Aleksei N; Pokrovskiy, Vitaly D; Banks, David; Frengstad, Bjørn S; Parnachev, Valerii P

    2017-11-01

    Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO 2 pressure (P CO2 , open system) of 10 -2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L -1 . Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L -1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO 3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U 3 O 7 and U 4 O 9 ). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L -1 , but with typical concentrations of up to 10 μg L -1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and P CO2 (low P CO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals). Copyright © 2017 Elsevier Ltd. All rights

  6. Evaluation and proposed study of potential ground-water supplies, Gallup area, New Mexico

    Science.gov (United States)

    Hiss, William L.

    1975-01-01

    The ground-water potential of 5 areas in central-western New Mexico within 85 miles (135 km) of Gallup, N. Mex. was evaluated by reviewing the published literature, inspecting aerial and space photographs, and interviewing ranchers and personnel employed by well-drilling and mineral-exploration companies by telephone. The San Andres Limestone and underlying Glorieta Sandstone of Permian age are the oldest aquifers capable of yielding water of a quality suitable for municipal use. Extreme local variations in hydraulic conductivity and water quality reflect a karstic topography developed on the San Andres Limestone prior to burial by Upper Triassic sediments. The San Andres Limestone and Glorieta Sandstone form an important aquifer in the Grants-Bluewater area where yields of as much as 2,200 gallons per minute (140 l/s) have been obtained. Yields from wells completed in the San Andres-Glorieta aquifer on the Chaco slope and in the Gallup sag-Mogollon slope on the northeast and southeast flanks, respectively, of the Zuni uplift will be much less than those prevailing in the Grants-Bluewater area. Water quality in the San Andres Limestone and Glorieta Sandstone deteriorates with distance away from the axis of the Zuni uplift. Sandstones of Triassic, Jurassic, and Cretaceous age are potential aquifers wherever they are present. Yields to wells tapping these aquifers are generally less than 200 gallons per minute (13 l/s) due to the relatively low hydraulic conductivity. Wells tapping alluvium of Late Cenozoic age along the Rio San Jose and Puerco River and interbedded volcanics and alluvium elsewhere in the area generally yield less than 100 gallons per minute (6 l/s) of water. Tributaries ,of the Rio San Jose that have eroded canyons into Paleozoic and Mesozoic rocks east of the Continental Divide and south of the eastern part of the Zuni uplift have been repeatedly displaced and (or) covered by Quaternary volcanic rocks. The exact location, extent, and depth of

  7. 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

    A hydrogeologic study was conducted in the portion of the Paradox Basin south of the Needles District of Canyonlands National Park, Utah. Geology of the study area comprises fractured and faulted Paleozoic sandstone, limestone, and shale, which are underlain by evaporite cycles of the Paradox Formation. The evaporite deposits deform and dissolve when they come in contact with groundwater, generating land subsidence, saline groundwater, and salt input to the Colorado River. Active faults in the region slip at a rate of approximately 2 mm/year, likely due to evaporite dissolution. The objective of this study is to better understand groundwater flow and solute transport dynamics and to help determine the rate and timing of subsurface salt dissolution, which is an important control on the salt tectonics in the region. Study methods include hydrologic fieldwork, laboratory tests, and numerical modeling. No groundwater wells exist in the study area. Water samples from springs and seeps were collected throughout the study area. Analysis of total dissolved solids (TDS), stable oxygen (δ18O) and deuterium (δD) isotopes, spring and seep locations, and prior data are used to gain a preliminary understanding of the shallow groundwater flow in the region. Stable isotope ratios of oxygen (18O/16O) and deuterium (D/H) are used to constrain the source of spring water. Measured δ values are compared to predicted δ values for precipitation from WaterIsotopes.org for each sample site. Measured isotopic values range from -14.9 ‰ to -10.7 ‰ for δ18O and -108 ‰ to -78 ‰ for δD. The majority of samples from above 2000 m match predicted isotopic values for precipitation. Most samples taken below 2000 m are lighter than predicted isotopic values for precipitation. The TDS of spring samples measured in the lab show they range from 184 mg/L to 1552 mg/L with the majority of samples between 220 - 430 mg/L. TDS shows a weak correlation (R2 = 0.54) with altitude, where lower TDS

  8. Use of isotopes to study groundwater recharge in arid zones: Application to the crystalline Ahaggar massif (central Sahara)

    International Nuclear Information System (INIS)

    Saighi, O.

    1999-01-01

    In the crystalline and igneous Ahaggar massif, the water resources are found in some small-scale phreatic aquifers which are recharged by sporadic wadi floods. The most favourable aquifer zones are localized in the valleys, consisting of three overlying levels of varying importance: the alluvial aquifer, the weathered zone of the underlying substratum, and the deep aquifer of fissured basement, the extent of which is not limited only to wadis. In order to evaluate the recharge to the different aquifers, chemical and isotopic analyses have been carried out on a hundred samples taken at different depths. Measurements of oxygen-18, deuterium, carbon-13, carbon-14 and tritium have been carried out on these samples

  9. Inverse Modeling of Water-Rock-CO2 Batch Experiments: Potential Impacts on Groundwater Resources at Carbon Sequestration Sites.

    Science.gov (United States)

    Yang, Changbing; Dai, Zhenxue; Romanak, Katherine D; Hovorka, Susan D; Treviño, Ramón H

    2014-01-01

    This study developed a multicomponent geochemical model to interpret responses of water chemistry to introduction of CO2 into six water-rock batches with sedimentary samples collected from representative potable aquifers in the Gulf Coast area. The model simulated CO2 dissolution in groundwater, aqueous complexation, mineral reactions (dissolution/precipitation), and surface complexation on clay mineral surfaces. An inverse method was used to estimate mineral surface area, the key parameter for describing kinetic mineral reactions. Modeling results suggested that reductions in groundwater pH were more significant in the carbonate-poor aquifers than in the carbonate-rich aquifers, resulting in potential groundwater acidification. Modeled concentrations of major ions showed overall increasing trends, depending on mineralogy of the sediments, especially carbonate content. The geochemical model confirmed that mobilization of trace metals was caused likely by mineral dissolution and surface complexation on clay mineral surfaces. Although dissolved inorganic carbon and pH may be used as indicative parameters in potable aquifers, selection of geochemical parameters for CO2 leakage detection is site-specific and a stepwise procedure may be followed. A combined study of the geochemical models with the laboratory batch experiments improves our understanding of the mechanisms that dominate responses of water chemistry to CO2 leakage and also provides a frame of reference for designing monitoring strategy in potable aquifers.

  10. Analysis of viticultural potential and delineation of homogeneous viticultural zones in a temperate climate region of Romania

    Directory of Open Access Journals (Sweden)

    Liviu Mihai Irimia

    2014-09-01

    Significance and impact of the study: This study provides the necessary information for viticultural zoning in the Huşi wine growing region in Romania. The methodology allows to evaluate viticultural potential and to delineate homogeneous viticultural zones in wine growing regions with a temperate continental climate.

  11. Potential impacts of climate change on groundwater supplies to the Doñana wetland, Spain

    OpenAIRE

    Jackson, Christopher R.; Guardiola-Albert, Carolina

    2011-01-01

    Climate change impacts on natural recharge and groundwater-wetland dynamics were investigated for the Almonte-Marismas aquifer, Spain, which supports the internationally important Doñana wetland. Simulations were carried out using outputs from 13 global climate models to assess the impacts of climate change. Reductions in flow from the aquifer to streams and springs flooding the wetland, induced by changes in recharge according to different climate projections, were modelled. The results proj...

  12. Hydrologic characterization of faults and other potentially conductive geologic features in the unsaturated zone

    International Nuclear Information System (INIS)

    Javandel, I.; Shan, C.

    1990-01-01

    The capability of characterizing near-vertical faults and other potentially highly conductive geologic features in the vicinity of a high-level-waste repository is of great importance in site characterization of underground waste-isolation projects. The possibility of using transient air pressure data at depth for characterizing these features in the unsaturated zone are investigated. Analytical solutions for calculating the pressure response of such systems are presented. Solutions are given for two types of barometric pressure fluctuations, step function and sinusoidal. 3 refs., 9 figs

  13. Abscisic Acid Accumulates at Positive Turgor Potential in Excised Soybean Seedling Growing Zones 1

    Science.gov (United States)

    Creelman, Robert A.; Mullet, John E.

    1991-01-01

    Abscisic acid (ABA) accumulated in soybean (Glycine max [L.] Merr. cv Williams) hypocotyl elongating regions when seedlings were transferred to low water potential vermiculite (Ψ = −0.3 megapascals) even though positive turgor is retained in this tissue. Accumulation of ABA in growing zones could occur from de novo biosynthesis within this tissue or transport from adjacent nongrowing zones. Both growing and nongrowing hypocotyl and root tissues accumulated significant levels of ABA when excised and dehydrated to reduce turgor. Surprisingly, excised growing zones (which experienced no water loss) also accumulated ABA when incubated in darkness for 4 hours at 100% relative humidity and 29°C. Induction of ABA accumulation in the excised elongating region of the hypocotyl was not caused by disruption of root pressure or wounding. While excision of hypocotyl elongating regions induced ABA accumulation, no change in either extensin or p33 mRNA levels was observed. Accumulation of extensin or p33 mRNA required more severe wounding. This suggests that ABA is not involved in the response of these genes in wounded tissue and that wound signals are not causing ABA accumulation in excised tissue. Accumulation of ABA in excised elongating regions was correlated with growth inhibition and a decline in turgor to the yield threshold (Ψ;p = 0.37 megapascals; R Matyssek, S Maruyama, JS Boyer [1988] Plant Physiol 86: 1163-1167). Inhibiting hypocotyl growth by transferring seedlings to lower temperatures or light did not cause ABA accumulation. We conclude that induction of ABA accumulation in growing zones is more sensitive to changes in turgor than the induction which occurs in mature tissues. Images Figure 2 PMID:16668113

  14. Abscisic Acid accumulates at positive turgor potential in excised soybean seedling growing zones.

    Science.gov (United States)

    Creelman, R A; Mullet, J E

    1991-04-01

    Abscisic acid (ABA) accumulated in soybean (Glycine max [L.] Merr. cv Williams) hypocotyl elongating regions when seedlings were transferred to low water potential vermiculite (Psi = -0.3 megapascals) even though positive turgor is retained in this tissue. Accumulation of ABA in growing zones could occur from de novo biosynthesis within this tissue or transport from adjacent nongrowing zones. Both growing and nongrowing hypocotyl and root tissues accumulated significant levels of ABA when excised and dehydrated to reduce turgor. Surprisingly, excised growing zones (which experienced no water loss) also accumulated ABA when incubated in darkness for 4 hours at 100% relative humidity and 29 degrees C. Induction of ABA accumulation in the excised elongating region of the hypocotyl was not caused by disruption of root pressure or wounding. While excision of hypocotyl elongating regions induced ABA accumulation, no change in either extensin or p33 mRNA levels was observed. Accumulation of extensin or p33 mRNA required more severe wounding. This suggests that ABA is not involved in the response of these genes in wounded tissue and that wound signals are not causing ABA accumulation in excised tissue. Accumulation of ABA in excised elongating regions was correlated with growth inhibition and a decline in turgor to the yield threshold (Psi;(p) = 0.37 megapascals; R Matyssek, S Maruyama, JS Boyer [1988] Plant Physiol 86: 1163-1167). Inhibiting hypocotyl growth by transferring seedlings to lower temperatures or light did not cause ABA accumulation. We conclude that induction of ABA accumulation in growing zones is more sensitive to changes in turgor than the induction which occurs in mature tissues.

  15. Soil chemistry and ground-water quality of the water-table zone of the surficial aquifer, Naval Submarine Base Kings Bay, Camden County, Georgia, 1998 and 1999

    Science.gov (United States)

    Leeth, David C.

    2002-01-01

    In 1998, the U.S. Geological Survey, in cooperation with the U.S. Department of the Navy, began an investigation to determine background ground-water quality of the water-table zone of the surficial aquifer and soil chemistry at Naval Submarine Base Kings Bay, Camden County, Georgia, and to compare these data to two abandoned solid- waste disposal areas (referred to by the U.S. Navy as Sites 5 and 16). The quality of water in the water-table zone generally is within the U.S. Environmental Protection Agency (USEPA) drinking-water regulation. The pH of ground water in the study area ranged from 4.0 to 7.6 standard units, with a median value of 5.4. Water from 29 wells is above the pH range and 3 wells are within the range of the USEPA secondary drinking-water regulation (formerly known as the Secondary Maximum Contaminant Level or SMCL) of 6.5 to 8.5 standard units. Also, water from one well at Site 5 had a chloride concentration of 570 milligrams per liter (mg/L,), which is above the USEPA secondary drinking-water regulation of 250 mg/L. Sulfate concentrations in water from two wells at Site 5 are above the USEPA secondary drinking-water regulation of 250 mg/L. Of 22 soil-sampling locations for this study, 4 locations had concentrations above the detection limit for either volatile organic compounds (VOCs), base-neutral acids (BNAs), or pesticides. VOCs detected in the study area include toluene in one background sample; and acetone in one background sample and one sample from Site 16--however, detection of these two compounds may be a laboratory artifact. Pesticides detected in soil at the Submarine Base include two degradates of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT): 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (4,4'-DDD) in one background sample, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (4,4'-DDE) in one background sample and one sample from Site 16; and dibenzofuran in one sample from Site 16. BNAs were detected in one background sample and in two

  16. GIS-based groundwater potential analysis using novel ensemble weights-of-evidence with logistic regression and functional tree models.

    Science.gov (United States)

    Chen, Wei; Li, Hui; Hou, Enke; Wang, Shengquan; Wang, Guirong; Panahi, Mahdi; Li, Tao; Peng, Tao; Guo, Chen; Niu, Chao; Xiao, Lele; Wang, Jiale; Xie, Xiaoshen; Ahmad, Baharin Bin

    2018-09-01

    The aim of the current study was to produce groundwater spring potential maps using novel ensemble weights-of-evidence (WoE) with logistic regression (LR) and functional tree (FT) models. First, a total of 66 springs were identified by field surveys, out of which 70% of the spring locations were used for training the models and 30% of the spring locations were employed for the validation process. Second, a total of 14 affecting factors including aspect, altitude, slope, plan curvature, profile curvature, stream power index (SPI), topographic wetness index (TWI), sediment transport index (STI), lithology, normalized difference vegetation index (NDVI), land use, soil, distance to roads, and distance to streams was used to analyze the spatial relationship between these affecting factors and spring occurrences. Multicollinearity analysis and feature selection of the correlation attribute evaluation (CAE) method were employed to optimize the affecting factors. Subsequently, the novel ensembles of the WoE, LR, and FT models were constructed using the training dataset. Finally, the receiver operating characteristic (ROC) curves, standard error, confidence interval (CI) at 95%, and significance level P were employed to validate and compare the performance of three models. Overall, all three models performed well for groundwater spring potential evaluation. The prediction capability of the FT model, with the highest AUC values, the smallest standard errors, the narrowest CIs, and the smallest P values for the training and validation datasets, is better compared to those of other models. The groundwater spring potential maps can be adopted for the management of water resources and land use by planners and engineers. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

    Science.gov (United States)

    Burow, Karen R.; Jurgens, Bryant C.; Kauffman, Leon J.; Phillips, Steven P.; Dalgish, Barbara A.; Shelton, Jennifer L.

    2008-01-01

    Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of public-supply wells in the Modesto area. A network of 23 monitoring wells was installed, and water and sediment samples were collected within the approximate zone of contribution of the public-supply well, to support a detailed analysis of physical and chemical conditions and processes affecting the water chemistry in the well. A three-dimensional, steady-state local ground-water-flow and transport model was developed to evaluate the age of ground water reaching the well and to evaluate the vulnerability of the well to nonpoint source input of nitrate and uranium. Particle tracking was used to compute pathlines and advective travel times in the ground-water flow model. The simulated ages of particles reaching the public-supply well ranged from 9 to 30,000 years, with a median of 54 years. The age of the ground water contributed to the public-supply well increased with depth below the water table. Measured nitrate concentrations, derived primarily from agricultural fertilizer, were highest (17 milligrams per liter) in shallow ground water and decreased with depth to background concentrations of less than 2 milligrams per liter in the deepest wells. Because the movement of water is predominantly downward as a result of ground-water development, and because geochemical conditions are generally oxic, high nitrate concentrations in shallow ground water are expected to continue moving downward without significant attenuation. Simulated long-term nitrate concentrations indicate that concentrations have peaked and will decrease in the public-supply well during the next 100 years

  18. Propagation of uncertainties for an evaluation of the Azores-Gibraltar Fracture Zone tsunamigenic potential

    Science.gov (United States)

    Antoshchenkova, Ekaterina; Imbert, David; Richet, Yann; Bardet, Lise; Duluc, Claire-Marie; Rebour, Vincent; Gailler, Audrey; Hébert, Hélène

    2016-04-01

    The aim of this study is to assess evaluation the tsunamigenic potential of the Azores-Gibraltar Fracture Zone (AGFZ). This work is part of the French project TANDEM (Tsunamis in the Atlantic and English ChaNnel: Definition of the Effects through numerical Modeling; www-tandem.cea.fr), special attention is paid to French Atlantic coasts. Structurally, the AGFZ region is complex and not well understood. However, a lot of its faults produce earthquakes with significant vertical slip, of a type that can result in tsunami. We use the major tsunami event of the AGFZ on purpose to have a regional estimation of the tsunamigenic potential of this zone. The major reported event for this zone is the 1755 Lisbon event. There are large uncertainties concerning source location and focal mechanism of this earthquake. Hence, simple deterministic approach is not sufficient to cover on the one side the whole AGFZ with its geological complexity and on the other side the lack of information concerning the 1755 Lisbon tsunami. A parametric modeling environment Promethée (promethee.irsn.org/doku.php) was coupled to tsunami simulation software based on shallow water equations with the aim of propagation of uncertainties. Such a statistic point of view allows us to work with multiple hypotheses simultaneously. In our work we introduce the seismic source parameters in a form of distributions, thus giving a data base of thousands of tsunami scenarios and tsunami wave height distributions. Exploring our tsunami scenarios data base we present preliminary results for France. Tsunami wave heights (within one standard deviation of the mean) can be about 0.5 m - 1 m for the Atlantic coast and approaching 0.3 m for the English Channel.

  19. Awareness for natural radiation potential zones in Archean Terrain of Chhattisgarh State

    International Nuclear Information System (INIS)

    Diwan, H.D.; Pande, S.K.

    2015-01-01

    In the environment, the natural radiations emitted by rocks and soils containing radioactive minerals, largely affected the human being in various aspects. The Chhattisgarh region characterized by the mineral of natural radiations with their relative distribution found in Granitic rocks of Archean age. Adjacent to Cratonic margins, exposures of outer fringes became suitable sites for radiation spread. It constituting towards the emission of radiation by the intrinsic content of minerals present in the host rock i.e. the terrestrial sources of radiation. The Archean terrain covers the surrounding areas of oval cup shaped sedimentary basin and it lies in the S.O.I. toposheet no. 64 G. H.I.K.L. To locate the marked potential zone for natural radiation, the investigation nearby aquatic component of main river and tributaries of Mahanadi river system is important. The presence of Granitic/ Pegmatite rocks at the boundaries of shield areas became promising areas for radiation generating mineral components. Occurrence in the potential zones expressed as lense shaped deposits or strips in dimension of IX1/2 with few hundred long belt. Presence of weathering of Uraninite minerals content remain yellow orange coloured impressions on the surface. In urban areas the background radiation in form of ionic radiation by the residential dwelling units accredates radiations. It needs awareness for Natural Radiation of under zones (NRPZ) in the region. To ensure the effective awareness programme, the area under consideration of natural radiation should take care of socially sustainable activities and spatio-temporal spread to motivate and implement various safety provisions. The model experiments can be sued from R and D point of view, also to alert the people to provide 'Safety, health and welfare of society'. (author)

  20. Environmental Geophysical Study of the Groundwater Mineralization in a Plot of the Cotonou Littoral Zone (South Benin

    Directory of Open Access Journals (Sweden)

    Yalo Nicaise

    2012-01-01

    Full Text Available Geophysical investigations comprising electrical resistivity and electromagnetic conductivities methods were deployed in a 350 m2 sector, strewn with 11 wells. Within the framework of an environmental study on a small scale in the south of Benin, the water conductivity of these wells was measured to determine in a direct way mineralization of the coastal water table in the littoral zone. This environmental study aimed to prospect by the geophysical methods the space extension of the water table mineralization obtained by direct measurements of water conductivity in the well and the depth of the fresh water/salted water interface in the coastal aquifer. Electromagnetic measurements of conductivities made it possible to chart a gradient of mineralization in the northwest direction. The logs of vertical electric soundings showed a deepening of the fresh water/salted water interface in the southern part and its rupture in the northern part. The electrical resistivities of the interface are sensitive to the degree of its mineralization. It has been observed that the geophysical methods in electrical and electromagnetic prospection are a great contribution to the environmental study of the water table mineralization in the littoral zone for a sustainable management of the water resource.

  1. Technical Potential Assessment for the Renewable Energy Zone (REZ) Process: A GIS-Based Approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nathan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Roberts, Billy J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-05

    Geographic Information Systems (GIS)-based energy resource and technical potential assessments identify areas capable of supporting high levels of renewable energy (RE) development as part of a Renewable Energy Zone (REZ) Transmission Planning process. This document expands on the REZ Process to aid practitioners in conducting GIS-based RE resource and technical potential assessments. The REZ process is an approach to plan, approve, and build transmission infrastructure that connects REZs - geographic areas that have high-quality RE resources, suitable topography and land-use designations, and demonstrated developer interest - to the power system. The REZ process helps to increase the share of solar photovoltaic (PV), wind, and other resources while also maintaining reliability and economics.

  2. Estimation of nearshore groundwater discharge and its potential effects on a fringing coral reef

    International Nuclear Information System (INIS)

    Blanco, Ariel C.; Watanabe, Atsushi; Nadaoka, Kazuo; Motooka, Shunsuke; Herrera, Eugene C.; Yamamoto, Takahiro

    2011-01-01

    Research highlights: → We characterized SGD in a fringing coral reef using radon tracing. → End-member Rn and gas transfer rate significantly affect flux estimation accuracy. → Reef SGD is strongly influenced by tidal pumping and hydraulic gradient. → SGD elevated nitrate concentrations, which drastically increased nearshore Chl-a. → SGD significantly induced the proliferation of cyanobacteria in nearshore reef areas. - Abstract: Radon ( 222 Rn) measurements were conducted in Shiraho Reef (Okinawa, Japan) to investigate nearshore submarine groundwater discharge (SGD nearshore ) dynamics. Estimated average groundwater flux was 2-3 cm/h (maximum 7-8 cm/h). End-member radon concentration and gas transfer coefficient were identified as major factors influencing flux estimation accuracy. For the 7-km long reef, SGD nearshore was 0.39-0.58 m 3 /s, less than 30% of Todoroki River's baseflow discharge. SGD nearshore was spatially and temporally variable, reflecting the strong influence of subsurface geology, tidal pumping, groundwater recharge, and hydraulic gradient. SGD nearshore elevated nearshore nitrate concentrations (0.8-2.2 mg/l) to half of Todoroki River's baseflow NO 3 - N (2-4 mg/L). This increased nearshore Chl-a from 0.5-2 μg/l compared to the typically low Chl-a (<0.1-0.4 μg/l) in the moat. Diatoms and cyanobacteria concentrations exhibited an increasing trend. However, the percentage contributions of diatoms and cyanobacteria significantly decreased and increased, respectively. SGD may significantly induce the proliferation of cyanobacteria in nearshore reef areas.

  3. Functional genes reveal the intrinsic PAH biodegradation potential in creosote-contaminated groundwater following in situ biostimulation.

    Science.gov (United States)

    Nyyssönen, Mari; Kapanen, Anu; Piskonen, Reetta; Lukkari, Tuomas; Itävaara, Merja

    2009-08-01

    A small-scale functional gene array containing 15 functional gene probes targeting aliphatic and aromatic hydrocarbon biodegradation pathways was used to investigate the effect of a pilot-scale air sparging and nutrient infiltration treatment on hydrocarbon biodegradation in creosote-contaminated groundwater. Genes involved in the different phases of polycyclic aromatic hydrocarbon (PAH) biodegradation were detected with the functional gene array in the contaminant plume, thus indicating the presence of intrinsic biodegradation potential. However, the low aerobic fluorescein diacetate hydrolysis, the polymerase chain reaction (PCR) amplification of 16S rRNA genes closely similar to sulphate-reducing and denitrifying bacteria and the negligible decrease in contaminant concentrations showed that aerobic PAH biodegradation was limited in the anoxic groundwater. Increased abundance of PAH biodegradation genes was detected by functional gene array in the monitoring well located at the rear end of the biostimulated area, which indicated that air sparging and nutrient infiltration enhanced the intrinsic, aerobic PAH biodegradation. Furthermore, ten times higher naphthalene dioxygenase gene copy numbers were detected by real-time PCR in the biostimulated area, which was in good agreement with the functional gene array data. As a result, functional gene array analysis was demonstrated to provide a potential tool for evaluating the efficiency of the bioremediation treatment for enhancing hydrocarbon biodegradation in field-scale applications.

  4. Abundance and diversity of methanogens: potential role in high arsenic groundwater in Hetao Plain of Inner Mongolia, China.

    Science.gov (United States)

    Wang, Y H; Li, P; Dai, X Y; Zhang, R; Jiang, Z; Jiang, D W; Wang, Y X

    2015-05-15

    To investigate the community diversity and abundance of methanogens and their potential role in high arsenic groundwater, 17 groundwater samples from Hetao Plain of Inner Mongolia were investigated with an integrated method including 16S rRNA gene clone library, quantitative polymerase chain reaction and geochemistry analyses. Total arsenic (AsTot) concentrations were 82.7-1088.7 μg/L and arsenite (AsIII) mostly dominated in these samples with percentages of 0.04-0.79. CH₄ concentrations ranged from 0.01 to 292 μg/L and distinctly elevated only when AsTot were relatively high and SO₄(2-) were distinctly low. Principal component analysis indicated that these samples were divided into three groups according to the variations of AsTot, CH₄ and SO₄(2-). AsTot concentrations were distinctly high in the group with high CH₄ and low SO₄(2-) comparing to the other two groups (one with high CH₄ and high SO₄(2-), the other with low CH₄ and SO₄(2-)). The mcrA gene (methyl coenzyme-M reductase gene) based phylogenetic analysis of methanogens population showed that methanogenic archaea was diverse but mainly composed of Methanomicrobiales, Methanosarcinales, Methanobacteria and unidentified groups, with Methanomicrobiales being distinctly dominant (50.6%). The mcrA gene abundance in high arsenic groundwater ranged from 3.01 × 10(3) to 3.80 × 10(6)copies/L and accounted for 0-30.2% of total archaeal 16S rRNA genes. The abundance of mcrA genes was positively correlated with the concentrations of AsTot (R=0.59), AsIII (R=0.57) and FeII (R=0.79), while it was negatively correlated with oxidation-reduction potential (R=-0.66) and SO₄(2-) concentration (R=-0.64). These results implied that methanogenic archaea might accelerate As release in groundwater aquifers in Hetao Plain. Copyright © 2015. Published by Elsevier B.V.

  5. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  6. Assessment of solar and wind energy potentials for three free economic and industrial zones of Iran

    International Nuclear Information System (INIS)

    Mohammadi, Kasra; Mostafaeipour, Ali; Sabzpooshani, Majid

    2014-01-01

    This paper aims to evaluate the potential of renewable energy sources of solar and wind in three free economic and industrial zones of Chabahar, Kish and Salafchegan in Iran. Feasibility of harnessing solar energy was investigated by using key solar parameters like monthly mean global, beam and diffuse solar radiation as well as clearness index. It was found that all locations had great potentials for utilizing different solar energy systems. Additionally, the monthly, seasonal, semi-yearly and yearly optimum tilt angles of south-facing solar surfaces were determined. For all zones, adjusting the tilt angle twice a year or in other words, the semi-yearly tilt adjustment for two periods of warm (April–September) and cold (October–March) were highly recommended, since it offers almost the same level of annual solar energy gain (SEG) as those of monthly and seasonal adjustments. Weibull Distribution Function (WDF) was performed for analyzing the wind potentials at different heights. It was found that Chabahar was not suitable for wind energy development, but Kish and Salafchegan with yearly wind powers of 111.28 W/m 2 and 114.34 W/m 2 , respectively ranked in class 2 which are considered marginal for wind power development. Three different wind turbine models were proposed for Kish and Salafchegan. - Highlights: • Feasibility of solar and wind energy for three locations of Iran was investigated. • All locations were suitable for solar energy utilization. • The optimum tilt angles of solar surfaces were determined. • Chabahar was unsuitable, but Kish and Salafchegan were marginal for wind purpose

  7. Evaluation of Cr in ophiolite and groundwater and its potential to contaminate the environment in SE of Birjand

    Directory of Open Access Journals (Sweden)

    Zahra Khaledi

    2012-10-01

    Full Text Available The presence of Cr(VI in groundwater resources is governed by pH and Eh of water and its compounds are generally soluble and have more toxicicity and mobility in oxidizing environments. In this article, the Cr concentration in ophiolite units, in sediments, and in groundwater resources, and also its potential to contaminate the environment have been investigated in southeast of Birjand. During sampling, 17 water samples (2 rain water samples and 15 groundwater samples, and 8 sediment samples were collected. The concentrations of cations (major cations and Cr and anions in water samples were measured at Ottawa University, Canada using IC and ICP-AES methods, respectively. Cr concentrations of sediments were measured using XRF, and concentrations of Cr in collected Selective Sequential Extraction (SSE fractions were measured using Atomic Absorption (AA at Ferdowsi University of Mashhad, Iran. The average Cr concentrations in sediments and water resources are 627 and 0.026 ppm, respectively. According to the pH of sediments and Eh-pH of water samples, the Cr in water resources is as Cr(VI. Furthermore, the results of SSE show that the majority of Cr was found with residual matter, attached to the iron and manganese oxides, bound to carbonates, organic matter, and the soluble fractions, respectively. The hydrogeochemical properties of water resources show that the average values of EC, TDS and pH are 509 mg/l, 1045 µs/cm and 8.1, respectively, and the concentrations of Cl-, Na+, Mg2+ and SO42- ions are higher than the levels of WHO and Iran National Standard (1053. According to the WQI classification, while 20 percent of the water resources have excellent quality, 53 percent show good quality and 20 percent of water resources are poor in quality.

  8. Historical and potential groundwater drawdown in the Bruneau area, Owyhee County, southwestern Idaho

    Science.gov (United States)

    Adkins, Candice B.; Bartolino, James R.

    2012-01-01

    Geothermal seeps and springs in the Bruneau area in southwestern Idaho provide a vital but disappearing habitat for the Bruneau hot springsnail (Pyrgulopsis bruneauensis). In order to aid in conservation efforts, a two-part study was conducted (1) to determine trends in groundwater levels over time and (2) to simulate drawdown in aquifers that contribute to the geothermal seeps and springs along the Bruneau River. Seasonal and Regional Kendall tests for trends were used to determine water-level trends over a 20-year monitoring (1990–2010) period. Seasonal Kendall tests were used to calculate trends in groundwater-levels in 22 monitoring wells and indicated statistically significant changes in water level with trends ranging from 0.21 to 1.0 feet per year. Regional Kendall tests were used to calculate drawdown in categories of wells based on five criteria (well depth, distance from Indian Bathtub Spring, geologic unit, regional topographic valley, and temperature). Results from Regional Kendall tests indicate that slope of the trend (in feet per year) increased as a function of well depth; trends in water level as a function of other categories did not exhibit an obvious pattern based on distance from Indian Bathtub Spring, geologic unit, topographic valley, or temperature. Analytical solutions were used to simulate drawdown and recovery in wells using the Theis equation and a range of hydraulic parameters. Drawdown effects were determined by changing the storativity, transmissivity, and flow values over a hypothetical timeline. For example, estimates projected that after 20 years of pumping (at an assumed storativity of 0.002, a transmissivity of 980,000 feet squared per day, and a flow of 100 acre-feet per year), 1 foot of drawdown in the volcanic-rock aquifers would not be detected; however, other estimates using the same time frame but different hydraulic parameters (storativity of 0.001, transmissivity of 13,000 feet squared per day, and 610 acre-feet per

  9. Conceptual and numerical models of groundwater flow and solute transport in fracture zones: Application to the Aspo Island (Sweden); Modelos conceptuales y numericos de flujo y transporte de solutos en zonas de fractura: aplicacion a la isla de Aspo (Suecia)

    Energy Technology Data Exchange (ETDEWEB)

    Molinero, J.; Samper, J.

    2003-07-01

    Several countries around the world are considering the final disposal of high-level radioactive waste in deep repositories located in fractured granite formations. Evaluating the long term safety of such repositories requires sound conceptual and numerical models which must consider simultaneously groundwater flow, solute transport and chemical and radiological processes. These models are being developed from data and knowledge gained from in situ experiments carried out at deep underground laboratories such as that of Aspo, Sweden, constructed in fractured granite. The Redox Zone Experiment is one of such experiments performed at Aspo in order to evaluate the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Previous authors interpreted hydrochemical and isotopic data of this experiment using a mass-balance approach based on a qualitative description of groundwater flow conditions. Such an interpretation, however, is subject to uncertainties related to an over-simplified conceptualization of groundwater flow. Here we present numerical models of groundwater flow and solute transport for this fracture zone. The first model is based on previously published conceptual model. It presents noticeable un consistencies and fails to match simultaneously observed draw downs and chloride breakthrough curves. To overcome its limitations, a revised flow and transport model is presented which relies directly on available hydrodynamic and transport parameters, is based on the identification of appropriate flow and transport boundary conditions and uses, when needed, solute data extrapolated from nearby fracture zones. A significant quantitative improvement is achieved with the revised model because its results match simultaneously drawdown and chloride data. Other improvements are qualitative and include: ensuring consistency of hydrodynamic and hydrochemical data and avoiding

  10. The deep hydrogeologic flow system underlying the Oak Ridge Reservation - Assessing the potential for active groundwater flow and origin of the brine

    International Nuclear Information System (INIS)

    Nativ, R.; Halleran, A.; Hunley, A.

    1997-08-01

    The deep hydrogeologic system underlying the Oak Ridge Reservation (ORR) contains contaminants such as radionuclides, heavy metals, nitrates, and organic compounds. The groundwater in the deep system is saline and has been considered to be stagnant in previous studies. This study was designed to address the following questions: is groundwater in the deep system stagnant; is contaminant migration controlled by diffusion only or is advection a viable mechanism; where are the potential outlet points? On the basis of existing and newly collected data, the nature of saline groundwater flow and potential discharge into shallow, freshwater systems was assessed. Data used for this purpose included (1) spatial and temporal pressures and hydraulic heads measured in the deep system, (2) hydraulic parameters of the formations in question, (3) spatial and temporal temperature variations at depth, and (4) spatial and temporal chemical and isotopic composition of the saline groundwater. The observations suggest that the saline water contained at depth is old but not isolated (in terms of recharge and discharge) from the overlying active, freshwater-bearing units. Influx of recent water does occur. Groundwater volumes involved in this flow are likely to be small. The origin of the saline groundwater was assessed by using existing and newly acquired chemical and isotopic data. The proposed model that best fits the data is modification of residual brine from which halite has been precipitated. Other models, such as ultrafiltration and halite dissolution, were also evaluated

  11. Existing and potential infection risk zones of yellow fever worldwide: a modelling analysis.

    Science.gov (United States)

    Shearer, Freya M; Longbottom, Joshua; Browne, Annie J; Pigott, David M; Brady, Oliver J; Kraemer, Moritz U G; Marinho, Fatima; Yactayo, Sergio; de Araújo, Valdelaine E M; da Nóbrega, Aglaêr A; Fullman, Nancy; Ray, Sarah E; Mosser, Jonathan F; Stanaway, Jeffrey D; Lim, Stephen S; Reiner, Robert C; Moyes, Catherine L; Hay, Simon I; Golding, Nick

    2018-03-01

    Yellow fever cases are under-reported and the exact distribution of the disease is unknown. An effective vaccine is available but more information is needed about which populations within risk zones should be targeted to implement interventions. Substantial outbreaks of yellow fever in Angola, Democratic Republic of the Congo, and Brazil, coupled with the global expansion of the range of its main urban vector, Aedes aegypti, suggest that yellow fever has the propensity to spread further internationally. The aim of this study was to estimate the disease's contemporary distribution and potential for spread into new areas to help inform optimal control and prevention strategies. We assembled 1155 geographical records of yellow fever virus infection in people from 1970 to 2016. We used a Poisson point process boosted regression tree model that explicitly incorporated environmental and biological explanatory covariates, vaccination coverage, and spatial variability in disease reporting rates to predict the relative risk of apparent yellow fever virus infection at a 5 × 5 km resolution across all risk zones (47 countries across the Americas and Africa). We also used the fitted model to predict the receptivity of areas outside at-risk zones to the introduction or reintroduction of yellow fever transmission. By use of previously published estimates of annual national case numbers, we used the model to map subnational variation in incidence of yellow fever across at-risk countries and to estimate the number of cases averted by vaccination worldwide. Substantial international and subnational spatial variation exists in relative risk and incidence of yellow fever as well as varied success of vaccination in reducing incidence in several high-risk regions, including Brazil, Cameroon, and Togo. Areas with the highest predicted average annual case numbers include large parts of Nigeria, the Democratic Republic of the Congo, and South Sudan, where vaccination coverage in 2016

  12. Existing and potential infection risk zones of yellow fever worldwide: a modelling analysis

    Directory of Open Access Journals (Sweden)

    Freya M Shearer, BSc

    2018-03-01

    Full Text Available Summary: Background: Yellow fever cases are under-reported and the exact distribution of the disease is unknown. An effective vaccine is available but more information is needed about which populations within risk zones should be targeted to implement interventions. Substantial outbreaks of yellow fever in Angola, Democratic Republic of the Congo, and Brazil, coupled with the global expansion of the range of its main urban vector, Aedes aegypti, suggest that yellow fever has the propensity to spread further internationally. The aim of this study was to estimate the disease's contemporary distribution and potential for spread into new areas to help inform optimal control and prevention strategies. Methods: We assembled 1155 geographical records of yellow fever virus infection in people from 1970 to 2016. We used a Poisson point process boosted regression tree model that explicitly incorporated environmental and biological explanatory covariates, vaccination coverage, and spatial variability in disease reporting rates to predict the relative risk of apparent yellow fever virus infection at a 5 × 5 km resolution across all risk zones (47 countries across the Americas and Africa. We also used the fitted model to predict the receptivity of areas outside at-risk zones to the introduction or reintroduction of yellow fever transmission. By use of previously published estimates of annual national case numbers, we used the model to map subnational variation in incidence of yellow fever across at-risk countries and to estimate the number of cases averted by vaccination worldwide. Findings: Substantial international and subnational spatial variation exists in relative risk and incidence of yellow fever as well as varied success of vaccination in reducing incidence in several high-risk regions, including Brazil, Cameroon, and Togo. Areas with the highest predicted average annual case numbers include large parts of Nigeria, the Democratic Republic of the

  13. Characterization of potential zones of dust generation at eleven stations in the southern Sahara

    Science.gov (United States)

    Clark, I.; Assamoi, P.; Bertrand, J.; Giorgi, F.

    Synoptic wind data for multi-decadal periods at eleven stations located in the southern Sahara region (Agadez, Atar, Bilma, Dori, Gao, Kayes, Nema, Niamey, Nouadhibou, Ouagadougou and Tessalit) are used to study the monthly dust deflation power over the region. We found that, regardless of the conditions of the soil, the deflation power (or wind efficiency) is not sufficient to generate significant amounts of aerosols south of 15°N. North of this latitude, the deflation power is much larger, with potential zones of either very strong deflation (Nouadhibou and Bilma) or severe deflation (Gao, Tessalit, Nema, Atar, Agadez). Stations in the Sahel region such as Gao, Agadez and Tessalit are characterized by a gradual reinforcement of the deflation power between 1970 and 1984 in correspondence of increasing desertification over the region. During this same period, Bilma, a well know region of dust source, experienced a major reduction in deflation power due to shifts in large scale wind patterns.

  14. Geophysical logging for groundwater investigations in Southern Thailand

    Directory of Open Access Journals (Sweden)

    Phongpiyah Klinmanee

    2012-09-01

    Full Text Available In Thailand the Department of Groundwater Resources is drilling to find vital aquifers. Sometimes groundwater formations cannot be identified clearly during drilling; therefore, geophysical logging was applied after drilling and before casing.The tool used here is measuring nine parameters in one run, natural gamma ray, spontaneous potential, single point resistance, normal resistivity (AM 8’’, 16’’, 32’’, and 64’’, mud temperature and resistivity. Cutting was used to support the geophysical interpretations. In many cases the groundwater bearing zones could be clearly identified. The combination of andthe possibility choosing from nine parameters measured provided the necessary data base to identify groundwater bearingzones in different environments. It has been demonstrated that in different wells different tools are favorable than others.Based on the conclusions of this study geophysical logging in groundwater exploration is recommended as a normalstandard technique that should be applied in every new well drilled.

  15. Exploring deep potential aquifer in water scarce crystalline rocks

    Indian Academy of Sciences (India)

    out to explore deep groundwater potential zone in a water scarce granitic area. As existing field condi- ... Decision support tool developed in granitic ter- .... cially in terms of fracture system, the aquifer char- acteristics ... Methodologies used.

  16. Geochemistry and the Understanding of Groundwater Systems

    Science.gov (United States)

    Glynn, P. D.; Plummer, L. N.; Weissmann, G. S.; Stute, M.

    2009-12-01

    Geochemical techniques and concepts have made major contributions to the understanding of groundwater systems. Advances continue to be made through (1) development of measurement and characterization techniques, (2) improvements in computer technology, networks and numerical modeling, (3) investigation of coupled geologic, hydrologic, geochemical and biologic processes, and (4) scaling of individual observations, processes or subsystem models into larger coherent model frameworks. Many applications benefit from progress in these areas, such as: (1) understanding paleoenvironments, in particular paleoclimate, through the use of groundwater archives, (2) assessing the sustainability (recharge and depletion) of groundwater resources, and (3) their vulnerability to contamination, (4) evaluating the capacity and consequences of subsurface waste isolation (e.g. geologic carbon sequestration, nuclear and chemical waste disposal), (5) assessing the potential for mitigation/transformation of anthropogenic contaminants in groundwater systems, and (6) understanding the effect of groundwater lag times in ecosystem-scale responses to natural events, land-use changes, human impacts, and remediation efforts. Obtaining “representative” groundwater samples is difficult and progress in obtaining “representative” samples, or interpreting them, requires new techniques in characterizing groundwater system heterogeneity. Better characterization and simulation of groundwater system heterogeneity (both physical and geochemical) is critical to interpreting the meaning of groundwater “ages”; to understanding and predicting groundwater flow, solute transport, and geochemical evolution; and to quantifying groundwater recharge and discharge processes. Research advances will also come from greater use and progress (1) in the application of environmental tracers to ground water dating and in the analysis of new geochemical tracers (e.g. compound specific isotopic analyses, noble gas

  17. Considering the potential effect of faulting on regional-scale groundwater flow: an illustrative example from Australia's Great Artesian Basin

    Science.gov (United States)

    Smerdon, Brian D.; Turnadge, Chris

    2015-08-01

    Hydraulic head measurements in the Great Artesian Basin (GAB), Australia, began in the early 20th century, and despite subsequent decades of data collection, a well-accepted smoothed potentiometric surface has continually assumed a contiguous aquifer system. Numerical modeling was used to produce alternative potentiometric surfaces for the Cadna-owie-Hooray aquifers with and without the effect of major faults. Where a fault created a vertical offset between the aquifers and was juxtaposed with an aquitard, it was assumed to act as a lateral barrier to flow. Results demonstrate notable differences in the central portion of the study area between potentiometric surfaces including faults and those without faults. Explicitly considering faults results in a 25-50 m difference where faults are perpendicular to the regional flow path, compared to disregarding faults. These potential barriers create semi-isolated compartments where lateral groundwater flow may be diminished or absent. Groundwater management in the GAB relies on maintaining certain hydraulic head conditions and, hence, a potentiometric surface. The presence of faulting has two implications for management: (1) a change in the inferred hydraulic heads (and associated fluxes) at the boundaries of regulatory jurisdictions; and (2) assessment of large-scale extractions occurring at different locations within the GAB.

  18. Compilation of data to estimate groundwater migration potential for constituents in active liquid discharges at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Ames, L.L.; Serne, R.J.

    1991-03-01

    A preliminary characterization of the constituents present in the 33 liquid waste streams at the US Department of Energy's Hanford Site has been completed by Westinghouse Hanford Company. In addition, Westinghouse Hanford has summarized the soil characteristics based on drill logs collected at each site that receives these liquid wastes. Literature searches were conducted and available Hanford-specific data were tabulated and reviewed. General literature on organic chemicals present in the liquid waste streams was also reviewed. Using all of this information, Pacific Northwest Laboratory has developed a best estimate of the transport characteristics (water solubility and soil adsorption properties) for those radionuclides and inorganic and organic chemicals identified in the various waste streams. We assume that the potential for transport is qualified through the four geochemical parameters: solubility, distribution coefficient, persistence (radiogenic or biochemical half-life), and volatility. Summary tables of these parameters are presented for more than 50 inorganic and radioactive species and more than 50 organic compounds identified in the liquid waste streams. Brief descriptions of the chemical characteristics of Hanford sediments, solubility, and adsorption processes, and of how geochemical parameters are used to estimate migration in groundwater-sediment environments are also presented. Groundwater monitoring data are tabulated for wells neighboring the facilities that receive the liquid wastes. 91 refs., 16 figs., 23 tabs.

  19. Compilation of data to estimate groundwater migration potential for constituents in active liquid discharges at the Hanford Site

    International Nuclear Information System (INIS)

    Ames, L.L.; Serne, R.J.

    1991-03-01

    A preliminary characterization of the constituents present in the 33 liquid waste streams at the US Department of Energy's Hanford Site has been completed by Westinghouse Hanford Company. In addition, Westinghouse Hanford has summarized the soil characteristics based on drill logs collected at each site that receives these liquid wastes. Literature searches were conducted and available Hanford-specific data were tabulated and reviewed. General literature on organic chemicals present in the liquid waste streams was also reviewed. Using all of this information, Pacific Northwest Laboratory has developed a best estimate of the transport characteristics (water solubility and soil adsorption properties) for those radionuclides and inorganic and organic chemicals identified in the various waste streams. We assume that the potential for transport is qualified through the four geochemical parameters: solubility, distribution coefficient, persistence (radiogenic or biochemical half-life), and volatility. Summary tables of these parameters are presented for more than 50 inorganic and radioactive species and more than 50 organic compounds identified in the liquid waste streams. Brief descriptions of the chemical characteristics of Hanford sediments, solubility, and adsorption processes, and of how geochemical parameters are used to estimate migration in groundwater-sediment environments are also presented. Groundwater monitoring data are tabulated for wells neighboring the facilities that receive the liquid wastes. 91 refs., 16 figs., 23 tabs

  20. Potential evapotranspiration trend analysis for different climatic zones in Khyber Pakhtunkhwa, Pakistan

    International Nuclear Information System (INIS)

    Nazeer, M.

    2012-01-01

    Estimation of potential evapotranspiration (ETo) plays a significant role in the study of water resources management. The study was conducted to investigate the change in potential evapotranspiration value during the past three decade in three diverse climatic zones of Khyber Pakhtunkhwa, Pakistan. Three Districts of Khyber Pakhtunkhwa, Pakistan (Chitral, Peshawar and D. I. Khan) were selected based on their climatic diversity. Thirty years climatic data (1981-2010) obtained from Pakistan Metrological Department, Islamabad and Agriculture Research Institute, Peshawar was used. Potential evapotranspiration was determined for three decades separately, as well as on mean monthly basis. World Meteorological Organization (WMO) technique was used for trend analysis. Results revealed highest ETo in D. I. Khan followed by Peshawar and Chitral. However, in the summer months ETo value was found highest in Chitral as compared to other selected Districts. Trend analysis results showed that decrease in ETo trend was observed in all the selected Districts with the passage of time. It can be concluded that ETo values decreased as compared to past in all the selected Districts without any discrimination of physical geography and location. (author)

  1. The Energy-Water Nexus: Spatially-Resolved Analysis of the Potential for Desalinating Brackish Groundwater by Use of Solar Energy

    Directory of Open Access Journals (Sweden)

    Jill B. Kjellsson

    2015-06-01

    Full Text Available This research looks at coupling desalination with renewable energy sources to create a high-value product (treated water from two low value resources (brackish groundwater and intermittent solar energy. Desalination of brackish groundwater is already being considered as a potential new water supply in Texas. This research uses Texas as a testbed for spatially-resolved analysis techniques while considering depth to brackish groundwater, water quality, and solar radiation across Texas to determine the locations with the best potential for integrating solar energy with brackish groundwater desalination. The framework presented herein can be useful for policymakers, regional planners, and project developers as they consider where to site desalination facilities coupled with solar photovoltaics. Results suggest that the northwestern region of Texas—with abundant sunshine and groundwater at relatively shallow depths and low salinity in areas with freshwater scarcity—has the highest potential for solar powered desalination. The range in capacity for solar photovoltaic powered reverse osmosis desalination was found to be 1.56 × 10—6 to 2.93 × 10—5 cubic meters of water per second per square meter of solar panel (m3/s/m2.

  2. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    Energy Technology Data Exchange (ETDEWEB)

    Pickering, D.A.; Laase, A.D. [Oak Ridge National Lab., TN (United States); Locke, D.A. [Oak Ridge Inst. for Science and Education, TN (United States)

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy`s Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  3. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    Energy Technology Data Exchange (ETDEWEB)

    Pickering, D.A.; Laase, A.D. (Oak Ridge National Lab., TN (United States)); Locke, D.A. (Oak Ridge Inst. for Science and Education, TN (United States))

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy's Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  4. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    International Nuclear Information System (INIS)

    Pickering, D.A.; Laase, A.D.; Locke, D.A.

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy's Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended

  5. Potential Groundwater Recharge from the Infiltration of Surface Runoff in Cold and Dry Creeks, Phase 2

    International Nuclear Information System (INIS)

    Waichler, Scott R.

    2005-01-01

    Runoff from Cold and Dry Creeks may provide an important source of groundwater recharge on the Hanford Site. This report presents estimates of total volume and distribution of such recharge from extreme precipitation events. Estimates were derived using a simple approach that combined the Soil Conservation Service curve number runoff method and an exponential-decay channel infiltration model. Fifteen-minute streamflow data from four gaging stations, and hourly precipitation data from one climate station, were used to compute curve numbers and calibrate the infiltration model. All data were from several storms occurring during January 1995. Design storm precipitation depths ranging from 1.6 to 2.7 inches were applied with computed curve numbers to produce total runoff/recharge of 7,700 to 15,900 ac-ft, or approximately 10 times the average annual rate from this recharge source as determined in a previous study. Approximately two-thirds of the simulated recharge occurred in the lower stream reaches contained in the broad alluvial valley that parallels State Highway 240 near the Hanford 200 Area

  6. Potential Groundwater Recharge from the Infiltration of Surface Runoff in Cold and Dry Creeks, Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Waichler, Scott R.

    2005-12-13

    Runoff from Cold and Dry Creeks may provide an important source of groundwater recharge on the Hanford Site. This report presents estimates of total volume and distribution of such recharge from extreme precipitation events. Estimates were derived using a simple approach that combined the Soil Conservation Service curve number runoff method and an exponential-decay channel infiltration model. Fifteen-minute streamflow data from four gaging stations, and hourly precipitation data from one climate station, were used to compute curve numbers and calibrate the infiltration model. All data were from several storms occurring during January 1995. Design storm precipitation depths ranging from 1.6 to 2.7 inches were applied with computed curve numbers to produce total runoff/recharge of 7,700 to 15,900 ac-ft, or approximately 10 times the average annual rate from this recharge source as determined in a previous study. Approximately two-thirds of the simulated recharge occurred in the lower stream reaches contained in the broad alluvial valley that parallels State Highway 240 near the Hanford 200 Area.

  7. Copolymers enhance selective bacterial community colonization for potential root zone applications.

    Science.gov (United States)

    Pham, Vy T H; Murugaraj, Pandiyan; Mathes, Falko; Tan, Boon K; Truong, Vi Khanh; Murphy, Daniel V; Mainwaring, David E

    2017-11-21

    Managing the impact of anthropogenic and climate induced stress on plant growth remains a challenge. Here we show that polymeric hydrogels, which maintain their hydrous state, can be designed to exploit functional interactions with soil microorganisms. This microbial enhancement may mitigate biotic and abiotic stresses limiting productivity. The presence of mannan chains within synthetic polyacrylic acid (PAA) enhanced the dynamics and selectivity of bacterial ingress in model microbial systems and soil microcosms. Pseudomonas fluorescens exhibiting high mannan binding adhesins showed higher ingress and localised microcolonies throughout the polymeric network. In contrast, ingress of Bacillus subtilis, lacking adhesins, was unaltered by mannan showing motility comparable to bulk liquids. Incubation within microcosms of an agricultural soil yielded hydrogel populations significantly increased from the corresponding soil. Bacterial diversity was markedly higher in mannan containing hydrogels compared to both control polymer and soil, indicating enhanced selectivity towards microbial families that contain plant beneficial species. Here we propose functional polymers applied to the potential root zone which can positively influence rhizobacteria colonization and potentially plant growth as a new approach to stress tolerance.

  8. Identification and characterization of potential discharge areas for radionuclide transport by groundwater from a nuclear waste repository in Sweden.

    Science.gov (United States)

    Berglund, Sten; Bosson, Emma; Selroos, Jan-Olof; Sassner, Mona

    2013-05-01

    This paper describes solute transport modeling carried out as a part of an assessment of the long-term radiological safety of a planned deep rock repository for spent nuclear fuel in Forsmark, Sweden. Specifically, it presents transport modeling performed to locate and describe discharge areas for groundwater potentially carrying radionuclides from the repository to the surface where man and the environment could be affected by the contamination. The modeling results show that topography to large extent determines the discharge locations. Present and future lake and wetland objects are central for the radionuclide transport and dose calculations in the safety assessment. Results of detailed transport modeling focusing on the regolith and the upper part of the rock indicate that the identification of discharge areas and objects considered in the safety assessment is robust in the sense that it does not change when a more detailed model representation is used.

  9. Potential Groundwater Recharge and the Effects of Soil Heterogeneity on Flow at Two Radioactive Waste Management Sites at the Nevada Test Site

    International Nuclear Information System (INIS)

    Yucel, V.; Levitt, D. G.

    2001-01-01

    Two low-level Radioactive Waste Management Sites (RWMSs), consisting of shallow land burial disposal units at the Nevada Test Site (NTS), are managed by Bechtel Nevada for the U.S. Department of Energy, National Nuclear Security Administration. The NTS has an arid climate with annual average precipitation of about 17 cm at the Area 3 RWMS and about 13 cm at the Area 5 RWMS. The vadose zone is about 490 m thick at the Area 3 RWMS, and about 235 m thick at the Area 5 RWMS. Numerous studies indicate that under current climatic conditions, there is generally no groundwater recharge at these sites. Groundwater recharge may occur at isolated locations surrounding the RWMSs, such as in large drainage washes. However, groundwater recharge scenarios (and radionuclide transport) at the RWMSs are modeled in support of Performance Assessment (PA) documents required for operation of each RWMS. Recharge scenarios include conditions of massive subsidence and flooding, and recharge resulting from deep infiltration through bare-soil waste covers. This paper summarizes the groundwater recharge scenarios and travel time estimates that have been conducted in support of the PAs, and examines the effects of soil hydraulic property heterogeneity on flow

  10. A water-budget approach to estimating potential groundwater recharge from two domestic sewage disposal fields in eastern Bernalillo County, New Mexico, 2011-12

    Science.gov (United States)

    Crilley, Dianna M.; Collison, Jake W.

    2015-08-04

    Eastern Bernalillo County, New Mexico, is a historically rural area that in recent years has experienced an increase in population and in the construction of new housing units, most of which are not connected to a centralized wastewater treatment system. Increasing water use has raised concerns about the effect of development on the available groundwater resources in the area. During 2011–12, the U.S. Geological Survey, in cooperation with Bernalillo County Public Works Natural Resource Services, used a water-budget approach to quantify the amount of potential groundwater recharge occurring from the domestic sewage (effluent) dosed to the sewage disposal field at two locations—sites A and B—in eastern Bernalillo County, N. Mex. The amount of effluent that is potentially available for groundwater recharge was determined as the mean daily volume of effluent dosed to the disposal field in excess of the mean daily volume of effluent loss from evapotranspiration from the disposal field.

  11. Evapotranspiration Within the Groundwater Model Domain of the Tuba City, Arizona, Disposal Site Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-03-01

    The revised groundwater model includes estimates of evapotranspiration (ET). The types of vegetation and the influences of ET on groundwater hydrology vary within the model domain. Some plant species within the model domain, classified as phreatophytes, survive by extracting groundwater. ET within these plant communities can result in a net discharge of groundwater if ET exceeds precipitation. Other upland desert plants within the model domain survive on meteoric water, potentially limiting groundwater recharge if ET is equivalent to precipitation. For all plant communities within the model domain, excessive livestock grazing or other disturbances can tip the balance to a net groundwater recharge. This task characterized and mapped vegetation within the groundwater model domain at the Tuba City, Arizona, Site, and then applied a remote sensing algorithm to estimate ET for each vegetation type. The task was designed to address five objectives: 1. Characterize and delineate different vegetation or ET zones within the groundwater model domain, focusing on the separation of plant communities with phreatophytes that survive by tapping groundwater and upland plant communities that are dependent on precipitation. 2. Refine a remote sensing method, developed to estimate ET at the Monument Valley site, for application at the Tuba City site. 3. Estimate recent seasonal and annual ET for all vegetation zones, separating phreatophytic and upland plant communities within the Tuba City groundwater model domain. 4. For selected vegetation zones, estimate ET that might be achieved given a scenario of limited livestock grazing. 5. Analyze uncertainty of ET estimates for each vegetation zone and for the entire groundwater model domain.

  12. Distribution, Community Composition, and Potential Metabolic Activity of Bacterioplankton in an Urbanized Mediterranean Sea Coastal Zone.

    Science.gov (United States)

    Richa, Kumari; Balestra, Cecilia; Piredda, Roberta; Benes, Vladimir; Borra, Marco; Passarelli, Augusto; Margiotta, Francesca; Saggiomo, Maria; Biffali, Elio; Sanges, Remo; Scanlan, David J; Casotti, Raffaella

    2017-09-01

    Bacterioplankton are fundamental components of marine ecosystems and influence the entire biosphere by contributing to the global biogeochemical cycles of key elements. Yet, there is a significant gap in knowledge about their diversity and specific activities, as well as environmental factors that shape their community composition and function. Here, the distribution and diversity of surface bacterioplankton along the coastline of the Gulf of Naples (GON; Italy) were investigated using flow cytometry coupled with high-throughput sequencing of the 16S rRNA gene. Heterotrophic bacteria numerically dominated the bacterioplankton and comprised mainly Alphaproteobacteria , Gammaproteobacteria , and Bacteroidetes Distinct communities occupied river-influenced, coastal, and offshore sites, as indicated by Bray-Curtis dissimilarity, distance metric (UniFrac), linear discriminant analysis effect size (LEfSe), and multivariate analyses. The heterogeneity in diversity and community composition was mainly due to salinity and changes in environmental conditions across sites, as defined by nutrient and chlorophyll a concentrations. Bacterioplankton communities were composed of a few dominant taxa and a large proportion (92%) of rare taxa (here defined as operational taxonomic units [OTUs] accounting for coastal zones is of critical importance, considering that these areas are highly productive and anthropogenically impacted. Their richness and evenness, as well as their potential activity, are very important to assess ecosystem health and functioning. Here, we investigated bacterial distribution, community composition, and potential metabolic activity in the GON, which is an ideal test site due to its heterogeneous environment characterized by a complex hydrodynamics and terrestrial inputs of varied quantities and quality. Our study demonstrates that bacterioplankton communities in this region are highly diverse and strongly regulated by a combination of different environmental

  13. Modeling of groundwater potential of the sub-basin of Siriri river, Sergipe state, Brazil, based on Geographic Information System and Remote Sensing

    Directory of Open Access Journals (Sweden)

    Washington Franca Rocha

    2011-08-01

    Full Text Available The use of Geographic Information System (GIS and Remote Sensing for modeling groundwater potential give support for the analysis and decision-making processes about water resource management in watersheds. The objective of this work consisted in modeling the groundwater water potential of Siriri river sub-basin, Sergipe state, based on its natural environment (soil, land use, slope, drainage density, lineament density, rainfall and geology using Remote Sensing and Geographic Information System as an integration environment. The groundwater potential map was done using digital image processing procedures of ENVI 4.4 software and map algebra of ArcGIS 9.3®. The Analytical Hierarchy Method was used for modeling the weights definition of the different criteria (maps. Loads and weights of the different classes were assigned to each map according to their influence on the overall objective of the work. The integration of these maps in a GIS environment and the AHP technique application allowed the development of the groundwater potential map in five classes: very low, low, moderate, high, very high. The average flow rates of wells confirm the potential of aquifers Sapucari, Barriers and Maruim since they are the most exploited in this sub-basin, with average flows of 78,113 L/h, 19,332 L/h and 12,085 L/h, respectively.

  14. On the potential for the Partial Triadic Analysis to grasp the spatio-temporal variability of groundwater hydrochemistry

    Science.gov (United States)

    Gourdol, L.; Hissler, C.; Pfister, L.

    2012-04-01

    instrument for hydrogeologists, in particular to characterize temporal and spatial hydrochemical variations induced by natural and anthropogenic factors. This new approach for groundwater management offers potential for 1) identifying a common multivariate spatial structure, 2) untapping the different hydrochemical patterns and explaining their controlling factors and 3) analysing the temporal variability of this structure and grasping hydrochemical changes.

  15. Determination of pumper truck intervention ratios in zones with high fire potential by using geographical information system

    Science.gov (United States)

    Aricak, Burak; Kucuk, Omer; Enez, Korhan

    2014-01-01

    Fighting forest fires not only depends on the forest type, topography, and weather conditions, but is also closely related to the technical properties of fire-fighting equipment. Firefighting is an important part of fire management planning. However, because of the complex nature of forests, creating thematic layers to generate potential fire risk maps is difficult. The use of remote sensing data has become an efficient method for the discrete classification of potential fire risks. The study was located in the Central District of the Kastamonu Regional Forest Directorate, covering an area of 24,320 ha, 15,685 ha of which is forested. On the basis of stand age, crown closure, and tree species, the sizes and distributions of potential fire risk zones within the study area were determined using high-resolution GeoEye satellite imagery and geographical information system data. The status of pumper truck intervention in zones with high fire risk and the sufficiency of existing forest roads within an existing forest network were discussed based on combustible matter characteristics. Pumper truck intervention was 83% for high-risk zones, 79% for medium-risk zones, and 78% for low-risk zones. A pumper truck intervention area map along existing roads was also created.

  16. Development of an automated processing system for potential fishing zone forecast

    Science.gov (United States)

    Ardianto, R.; Setiawan, A.; Hidayat, J. J.; Zaky, A. R.

    2017-01-01

    The Institute for Marine Research and Observation (IMRO) - Ministry of Marine Affairs and Fisheries Republic of Indonesia (MMAF) has developed a potential fishing zone (PFZ) forecast using satellite data, called Peta Prakiraan Daerah Penangkapan Ikan (PPDPI). Since 2005, IMRO disseminates everyday PPDPI maps for fisheries marine ports and 3 days average for national areas. The accuracy in determining the PFZ and processing time of maps depend much on the experience of the operators creating them. This paper presents our research in developing an automated processing system for PPDPI in order to increase the accuracy and shorten processing time. PFZ are identified by combining MODIS sea surface temperature (SST) and chlorophyll-a (CHL) data in order to detect the presence of upwelling, thermal fronts and biological productivity enhancement, where the integration of these phenomena generally representing the PFZ. The whole process involves data download, map geo-process as well as layout that are carried out automatically by Python and ArcPy. The results showed that the automated processing system could be used to reduce the operator’s dependence on determining PFZ and speed up processing time.

  17. The origin of high silicon content in potentially medicinal groundwater of Gran Canaria (Canary Islands, Spain. Modelling of chemical water-rock interactions

    Directory of Open Access Journals (Sweden)

    Dobrzyński, Dariusz

    2012-11-01

    Full Text Available Groundwater of Gran Canaria (Canary Island, Spain have been appreciated and used as an element of health tourism since the 19th Century. This activity was abandoned in the second half of 20th Century when springs disappeared due to groundwater drawdown. The chemistry of groundwater from 19 intakes in volcanic rocks of the north part of Gran Canaria was studied by applying geochemical modelling for quantifying processes responsible for high Si concentrations.Studied groundwater has temperature of 16.3°C–25.5°C, pH of 4.40–7.40, and usually HCO3-(Cl-Mg-Ca-Na hydrochemical types. At near-neutral pH, fresh groundwater usually has 0.1-0.3 mM of Si. In studied groundwater Si concentrations are 0.42 to 1.82 mM, and show positive correlation with ionic strength and temperature. Volcanic bedrocks consist of, generally, easily reactive silicate minerals. Weathering is not supported by low rainfall; however, it shall be intensified by high influx of salts from marine aerosols and lithogenic carbon dioxide into groundwater. Geochemical modelling has found water-mineral reactions which reflect properly diversity of bedrock mineralogy. Based on those chemical reactions, contributions of particular silicate minerals to the pool of silicon dissolved in groundwater were calculated. Understanding the processes responsible for water chemistry might help in proper management and protection of groundwater.The Si-rich waters might be found in numerous places of Gran Canaria in all volcanic rocks. Silicic acid is the only form of silicon which is biologically available, and is regarded as a component which provides balneotherapeutic benefits. Many studies have showed beneficial and essential aspects of silicon in humans. Studied groundwater from Gran Canaria has an unexploited balneotherapeutic potential, and due to very high Si contents they seem to be ideal for testing the health benefits of such waters to humans. Hydrogeochemical methods, including

  18. 3D geostatistical modelling for identifying sinkhole disaster potential zones around the Verkhnekamskoye potash deposit (Russia)

    Science.gov (United States)

    Royer, J. J.; Litaudon, J.; Filippov, L. O.; Lyubimova, T.; Maximovich, N.

    2017-07-01

    This work results from a cooperative scientific program between the Perm State University (Russia) and the University of Lorraine (France). Its objectives are to integrate modern 3D geomodeling in order to improve sustainable mining extraction, especially for predicting and avoiding the formation of sinkholes disaster potential zones. Systematic exploration drill holes performed in the Verkhnekamskoye potash deposit (Perm region, Russia) have been used to build a comprehensive 3D model for better understanding the spatial repartition of the ore quality (geometallurgy). A precise modelling of the mineralized layers allows an estimation of the in-situ ore reserves after interpolating by kriging the potassium (K) and magnesium (Mg) contents at the node of a regular centred grid (over a million cells). Total resources in potassium vary according to the cut-off between 4.7Gt @ 16.1 % K2O; 0.32 % MgCl2 for a cut-off grade at 13.1% K2O and 2.06 Gt @ 18.2 % K2O; 0.32 % MgCl2 at a cut-off of 16.5% K2O. Most of reserves are located in the KPI, KPII and KPIII layers, the KPI being the richest, and KPIII the largest in terms of tonnage. A systematic study of the curvature calculated along the roof of the mineralized layers points out the location of potential main faults which play a major role in the formation of sinkhole during exploitation. A risk map is then derived from this attribute.

  19. Study on the distribution of streaming potential while groundwater pumping up; Chikasui no kumiage ni tomonau ryudo den`i hassei ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Sato, H; Shima, H; Sakurai, K [OYO Corp., Tokyo (Japan)

    1997-10-22

    This paper describes effectiveness of water channel prospecting by means of streaming potential method. To investigate the distribution of streaming potential on the ground surface while groundwater pumping up, some laboratory experiments were performed. A system was constructed, in which fluid is flowed in an experimental cistern from its both ends and self-flowed through a strainer pipe fixed for flowing out the fluid at the center of the cistern. Streaming potential with the flowing of the fluid was observed. Positive streaming potential waveform was generated with the flowing of the fluid, and the potential increased with approaching the strainer pipe. A groundwater pumping test facility was used as a field test site. There was a positive maximal point of potential distribution at about 30 m far from the pumping well in the southeast direction. The potential gradually decreased in the eastern part from the maximal point. The potential steeply decreased in the northwest direction from the pumping well. From these experiments, it was found that the groundwater flow and underground structures can be reflected by the distribution of streaming potential, and that the present method is effective for water channel prospecting. 3 refs., 8 figs.

  20. Resistivity and self-potential tomography applied to groundwater remediation and contaminant plumes: Sandbox and field experiments

    Science.gov (United States)

    Mao, D.; Revil, A.; Hort, R. D.; Munakata-Marr, J.; Atekwana, E. A.; Kulessa, B.

    2015-11-01

    Geophysical methods can be used to remotely characterize contaminated sites and monitor in situ enhanced remediation processes. We have conducted one sandbox experiment and one contaminated field investigation to show the robustness of electrical resistivity tomography and self-potential (SP) tomography for these applications. In the sandbox experiment, we injected permanganate in a trichloroethylene (TCE)-contaminated environment under a constant hydraulic gradient. Inverted resistivity tomograms are able to track the evolution of the permanganate plume in agreement with visual observations made on the side of the tank. Self-potential measurements were also performed at the surface of the sandbox using non-polarizing Ag-AgCl electrodes. These data were inverted to obtain the source density distribution with and without the resistivity information. A compact horizontal dipole source located at the front of the plume was obtained from the inversion of these self-potential data. This current dipole may be related to the redox reaction occurring between TCE and permanganate and the strong concentration gradient at the front of the plume. We demonstrate that time-lapse self-potential signals can be used to track the kinetics of an advecting oxidizer plume with acceptable accuracy and, if needed, in real time, but are unable to completely resolve the shape of the plume. In the field investigation, a 3D resistivity tomography is used to characterize an organic contaminant plume (resistive domain) and an overlying zone of solid waste materials (conductive domain). After removing the influence of the streaming potential, the identified source current density had a magnitude of 0.5 A m-2. The strong source current density may be attributed to charge movement between the neighboring zones that encourage abiotic and microbially enhanced reduction and oxidation reactions. In both cases, the self-potential source current density is located in the area of strong resistivity

  1. Simulated potential and water-limited yields of cocoa under different agro-ecological zones in Peninsular Malaysia

    NARCIS (Netherlands)

    Zabawi, A.G.M.; Gerritsma, W.

    2009-01-01

    The yield of cocoa under potential and water-limited production levels in different agro-ecological zones was simulated using cocoa model CASE2. For both production levels, the yield was simulated using five years of elirnatic data (1991-1995) and plant data of three-year-old plant. The results

  2. The role of microbial community composition and groundwater chemistry in determining isoproturon degradation potential in UK aquifers.

    Science.gov (United States)

    Johnson, Andrew; Llewellyn, Neville; Smith, Jennifer; van der Gast, Christopher; Lilley, Andrew; Singer, Andrew; Thompson, Ian

    2004-07-01

    The community response of indigenous sandstone, chalk and limestone groundwater microorganisms to the addition of the commonly used herbicide isoproturon was examined. The addition of 100 microg l(-1) isoproturon generally caused an increase in species diversity determined by chemotaxonomic analysis (fatty methyl ester analysis) of isolates resulting from incubation of cultures at 18 degrees C for 4 days. Amongst the groundwater samples to which isoproturon was added, isoproturon degradation rates were correlated with increasing dominance of a few species. However, the changes in community profile associated with isoproturon degradation varied from site to site. Repeated sub-culturing with 100 microg l(-1) isoproturon and sterile groundwater was carried out to examine whether this level of pesticide could exert a selection pressure, and hence stimulate more rapid degradation. Significantly increased degradation was observed in a groundwater sample from the chalk, but not in sandstone, or limestone samples. The addition of filter-sterilised sandstone groundwater to bacteria on filter paper from slow degrading limestone sites significantly improved their degrading performance. The addition of filter-sterilised limestone groundwater to the sandstone bacteria reduced their degradation rate only slightly. The data suggested that the nature of the indigenous community does influence pesticide degradation in groundwater, but that the groundwater chemistry may also play a role.

  3. Groundwater monitoring program plan and conceptual site model for the Al-Tuwaitha Nuclear Research Center in Iraq.

    Energy Technology Data Exchange (ETDEWEB)

    Copland, John Robin; Cochran, John Russell

    2013-07-01

    The Radiation Protection Center of the Iraqi Ministry of Environment is developing a groundwater monitoring program (GMP) for the Al-Tuwaitha Nuclear Research Center located near Baghdad, Iraq. The Al-Tuwaitha Nuclear Research Center was established in about 1960 and is currently being cleaned-up and decommissioned by Iraqs Ministry of Science and Technology. This Groundwater Monitoring Program Plan (GMPP) and Conceptual Site Model (CSM) support the Radiation Protection Center by providing: A CSM describing the hydrogeologic regime and contaminant issues, recommendations for future groundwater characterization activities, and descriptions of the organizational elements of a groundwater monitoring program. The Conceptual Site Model identifies a number of potential sources of groundwater contamination at Al-Tuwaitha. The model also identifies two water-bearing zones (a shallow groundwater zone and a regional aquifer). The depth to the shallow groundwater zone varies from approximately 7 to 10 meters (m) across the facility. The shallow groundwater zone is composed of a layer of silty sand and fine sand that does not extend laterally across the entire facility. An approximately 4-m thick layer of clay underlies the shallow groundwater zone. The depth to the regional aquifer varies from approximately 14 to 17 m across the facility. The regional aquifer is composed of interfingering layers of silty sand, fine-grained sand, and medium-grained sand. Based on the limited analyses described in this report, there is no severe contamination of the groundwater at Al-Tuwaitha with radioactive constituents. However, significant data gaps exist and this plan recommends the installation of additional groundwater monitoring wells and conducting additional types of radiological and chemical analyses.

  4. Infrastructure and mechanical properties of a fault zone in sandstone as an outcrop analogue of a potential geothermal reservoir

    Science.gov (United States)

    Bauer, J. F.; Meier, S.; Philipp, S. L.

    2013-12-01

    Due to high drilling costs of geothermal projects, it is economically sensible to assess the potential suitability of a reservoir prior to drilling. Fault zones are of particular importance, because they may enhance fluid flow, or be flow barriers, respectively, depending on their particular infrastructure. Outcrop analogue studies are useful to analyze the fault zone infrastructure and thereby increase the predictability of fluid flow behavior across fault zones in the corresponding deep reservoir. The main aims of the present study are to 1) analyze the infrastructure and the differences of fracture system parameters in fault zones and 2) determine the mechanical properties of the faulted rocks. We measure fracture frequencies as well as orientations, lengths and apertures and take representative rock samples for each facies to obtain Young's modulus, compressive and tensile strengths in the laboratory. Since fractures reduce the stiffnesses of in situ rock masses we use an inverse correlation of the number of discontinuities to calculate effective (in situ) Young's moduli to investigate the variation of mechanical properties in fault zones. In addition we determine the rebound hardness, which correlates with the compressive strength measured in the laboratory, with a 'Schmidt-Hammer' in the field because this allows detailed maps of mechanical property variations within fault zones. Here we present the first results for a fault zone in the Triassic Lower Bunter of the Upper Rhine Graben in France. The outcrop at Cleebourg exposes the damage zone of the footwall and a clear developed fault core of a NNW-SSE-striking normal fault. The approximately 15 m wide fault core consists of fault gouge, slip zones, deformation bands and host rock lenses. Intensive deformation close to the core led to the formation of a distal fault core, a 5 m wide zone with disturbed layering and high fracture frequency. The damage zone also contains more fractures than the host rock

  5. Salinity of deep groundwater in California: Water quantity, quality, and protection

    Science.gov (United States)

    Kang, Mary; Jackson, Robert B.

    2016-01-01

    Deep groundwater aquifers are poorly characterized but could yield important sources of water in California and elsewhere. Deep aquifers have been developed for oil and gas extraction, and this activity has created both valuable data and risks to groundwater quality. Assessing groundwater quantity and quality requires baseline data and a monitoring framework for evaluating impacts. We analyze 938 chemical, geological, and depth data points from 360 oil/gas fields across eight counties in California and depth data from 34,392 oil and gas wells. By expanding previous groundwater volume estimates from depths of 305 m to 3,000 m in California’s Central Valley, an important agricultural region with growing groundwater demands, fresh [groundwater volume is almost tripled to 2,700 km3, most of it found shallower than 1,000 m. The 3,000-m depth zone also provides 3,900 km3 of fresh and saline water, not previously estimated, that can be categorized as underground sources of drinking water (USDWs; freshwater zones and USDWs, respectively, in the eight counties. Deeper activities, such as wastewater injection, may also pose a potential threat to groundwater, especially USDWs. Our findings indicate that California’s Central Valley alone has close to three times the volume of fresh groundwater and four times the volume of USDWs than previous estimates suggest. Therefore, efforts to monitor and protect deeper, saline groundwater resources are needed in California and beyond. PMID:27354527

  6. Evaluation of groundwater quality and assessment of scaling potential and corrosiveness of water samples in Kadkan aquifer, Khorasan-e-Razavi Province, Iran.

    Science.gov (United States)

    Esmaeili-Vardanjani, Mostafa; Rasa, Iraj; Amiri, Vahab; Yazdi, Mohammad; Pazand, Kaveh

    2015-02-01

    The chemical analysis of 129 groundwater samples in the Kadkan area, Khorasan-e-Razavi Province, NE of Iran was evaluated to determine the hydrochemical processes, assessment of groundwater quality for irrigation purposes, corrosiveness, and scaling potential of the groundwater. Accordingly, the suitability of groundwater for irrigation was evaluated based on the sodium adsorption ratio, residual sodium carbonate, sodium percent, salinity hazard, and US Salinity Laboratory hazard diagram. Based on the electrical conductivity and sodium adsorption ratio, the dominant classes are C3-S1, C3-S2, C2-S1, and C4-S2. According to the Wilcox plot, about 50 % of the samples fall in the "Excellent to Good" and "Good to Permissible" classes. Besides, the Langelier saturation index, Ryznar stability index (RSI), Larson-Skold index, and Puckorius scaling index were evaluated for assessing the corrosiveness and scaling potential of the groundwater. Corrosiveness and scaling indices stated that the majority of samples are classified into "Aggressive" and "Very Aggressive" category. In addition, chloride and sulfate interfere in 90 % of the samples. Assessment of hydrochemical characteristics indicates Na-Mg-Cl as the predominant hydrochemical type. Spatial distribution of hydrochemical parameters indicates that hydrochemical processes are influenced by geology and hydrogeology of Kadkan aquifer. The Gibbs plots gave an indication that groundwater chemistry in this area may have acquired the chemistry mainly from evaporation and mineral precipitation. Grouping the samples based on Q-mode hierarchical cluster analysis helped to more separation of similar samples. The R-mode HCA grouped analyzed parameters into two groups based on similarity of hydrochemical characteristics. As a result, the samples collected in northern and southern parts of the study area show the best quality (i.e., lowest salinity) for some purposes such as irrigation and drinking.

  7. Adsorptive properties of alluvial soil for arsenic(V) and its potential for protection of the shallow groundwater among Changsha, Zhuzhou, and Xiangtan cities, China.

    Science.gov (United States)

    Chen, Hongwei; Mei, Jinhua; Luo, Yueping; Qiu, Anni; Wang, Huan

    2017-02-01

    The study area is among Changsha, Zhuzhou, and Xiangtan cities, which was under agricultural use and natural conditions about 10 years ago and now is becoming part of the metropolis because of the urban expansion. This study aims to investigate the mechanisms and capabilities of the local alluvial soil layer for protecting the local shallow groundwater from arsenic pollution by field surveys and batch experiments. The field surveys showed that there was an acidic tendency of the groundwater, and phosphate, nitrate, and arsenic in the groundwater significantly increased comparing to their reference values. It indicates that the disturbance of the former agricultural land due to the change of land use may be responsible for these changes. From the experimental results, the maximum adsorption capacity of the soil for As(V) was as low as 0.334 mg/g, and lower As(V) adsorption capacities were obtained at higher As(V) concentration, higher pH, and lower temperature. The presence of H 2 PO 4 - and SiO 3 2- posed negative, while HCO 3 - slight positive, and SO 4 2- , NO 3 - and Cl - negligible influences on the As(V) adsorption. The surface-derived organic matter played a negative role in the adsorption process, and low specific surface area influenced adsorption capacity of the soil. The study reveals that the local soil layer shows poor potential for protection of the local shallow groundwater from As(V) pollution, and the change trends of the groundwater environments due to more intensive anthropogenic activities will further weaken this potential and increase the risk of the groundwater contamination.

  8. Hot spots and hot moments in riparian zones: potential for improved water quality management

    Science.gov (United States)

    Despite considerable heterogeneity over space and time, biogeochemical and hydrological processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. Recently, these heterogeneous processes have been co...

  9. Deep Vadose Zone Treatability Test of Soil Desiccation for the Hanford Central Plateau: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chronister, Glen B. [CH2M Hill Plateau Remediation Co., Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tartakovsky, Guzel D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Vicky L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rockhold, Mark L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greenwood, William J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Peterson, John E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hubbard, Susan S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ward, Anderson L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2018-02-20

    Some of the inorganic and radionuclide contaminants in the deep vadose zone at the Hanford Site are at depths where direct exposure pathways are not of concern, but may need to be remediated to protect groundwater. The Department of Energy developed a treatability test program for technologies to address Tc-99 and uranium in the deep vadose zone. These contaminants are mobile in the subsurface environment, have been detected at high concentrations deep in the vadose zone, and at some locations have reached groundwater. The treatability test of desiccation described herein was conducted as an element of the deep vadose zone treatability test program. Desiccation was shown to be a potentially effective vadose zone remediation technology to protect groundwater when used in conjunction with a surface infiltration barrier.

  10. Factors Effecting the Fate and Transport of CL-20 in the Vadose Zone and Groundwater: Final Report 2002 - 2004 SERDP Project CP-1255

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Riley, Robert G.; Devary, Brooks J.; Girvin, Donald C.; Resch, Charles T.; Campbell, James A.; Fredrickson, Herbert L.; Thompson, Karen T.; Crocker, Fiona H.; Qasim, Mohammad M.; Gamerdinger, Amy P.; Lemond, Luke A.

    2005-06-01

    This SERDP-funded project was initiated to investigate the fate of CL-20 in the subsurface environment, with a focus on identification and quantification of geochemical and microbial reactions of CL-20. CL-20 can be released to the surface and subsurface terrestrial environment by: a) manufacturing processes, b) munition storage, and c) use with low order detonation or unexploded ordnance. The risk of far-field subsurface migration was assessed through labora-tory experiments with a variety of sediments and subsurface materials to quantify processes that control CL-20 sorption-limited migration and degradation. Results of this study show that CL-20 will exhibit differing behavior in the subsurface terrestrial environment: 1. CL-20 on the sediment surface will photodegrade and interact with plants/animals (described in other SERDP projects CU 1254, 1256). CL-20 will exhibit greater sorption in humid sediments to organic matter. Transport will be solubility limited (i.e., low CL-20 aqueous solubility). 2. CL-20 infiltration into soils (<2 m) from spills will be subject to sorption to soil organic matter (if present), and low to high biodegradation rates (weeks to years) depending on the microbial population (greater in humid environment). 3. CL-20 in the vadose zone (>2 m) will be, in most cases, subject to low sorption and low degradation rates, so would persist in the subsurface environment and be at risk for deep migration. Low water content in arid regions will result in a decrease in both sorption and the degradation rate. Measured degradation rates in unsaturated sediments of years would result in significant subsurface migration distances. 4. CL-20 in groundwater will be subject to some sorption but likely very slow degradation rates. CL-20 sorption will be greater than RDX. Most CL-20 degradation will be abiotic (ferrous iron and other transition metals), because most deep subsurface systems have extremely low natural microbial populations. Degradation rates

  11. Groundwater vulnerability maps for pesticides for Flanders

    Science.gov (United States)

    Dams, Jef; Joris, Ingeborg; Bronders, Jan; Van Looy, Stijn; Vanden Boer, Dirk; Heuvelmans, Griet; Seuntjens, Piet

    2017-04-01

    Pesticides are increasingly being detected in shallow groundwater and and are one of the main causes of the poor chemical status of phreatic groundwater bodies in Flanders. There is a need for groundwater vulnerability maps in order to design monitoring strategies and land-use strategies for sensitive areas such as drinking water capture zones. This research focuses on the development of generic vulnerability maps for pesticides for Flanders and a tool to calculate substance-specific vulnerability maps at the scale of Flanders and at the local scale. (1) The generic vulnerability maps are constructed using an index based method in which maps of the main contributing factors in soil and saturated zone to high concentrations of pesticides in groundwater are classified and overlain. Different weights are assigned to the contributing factors according to the type of pesticide (low/high mobility, low/high persistence). Factors that are taken into account are the organic matter content and texture of soil, depth of the unsaturated zone, organic carbon and redox potential of the phreatic groundwater and thickness and conductivity of the phreatic layer. (2) Secondly a tool is developed that calculates substance-specific vulnerability maps for Flanders using a hybrid approach where a process-based leaching model GeoPEARL is combined with vulnerability indices that account for dilution in the phreatic layer. The GeoPEARL model is parameterized for Flanders in 1434 unique combinations of soil properties, climate and groundwater depth. Leaching is calculated for a 20 year period for each 50 x 50 m gridcell in Flanders. (3) At the local scale finally, a fully process-based approach is applied combining GeoPEARL leaching calculations and flowline calculations of pesticide transport in the saturated zone to define critical zones in the capture zone of a receptor such as a drinking water well or a river segment. The three approaches are explained more in detail and illustrated

  12. Use of mineral/solution equilibrium calculations to assess the potential for carnotite precipitation from groundwater in the Texas Panhandle, USA

    Science.gov (United States)

    Ranalli, Anthony J.; Yager, Douglas B.

    2016-01-01

    This study investigated the potential for the uranium mineral carnotite (K2(UO2)2(VO4)2·3H2O) to precipitate from evaporating groundwater in the Texas Panhandle region of the United States. The evolution of groundwater chemistry during evaporation was modeled with the USGS geochemical code PHREEQC using water-quality data from 100 groundwater wells downloaded from the USGS National Water Information System (NWIS) database. While most modeled groundwater compositions precipitated calcite upon evaporation, not all groundwater became saturated with respect to carnotite with the system open to CO2. Thus, the formation of calcite is not a necessary condition for carnotite to form. Rather, the determining factor in achieving carnotite saturation was the evolution of groundwater chemistry during evaporation following calcite precipitation. Modeling in this study showed that if the initial major-ion groundwater composition was dominated by calcium-magnesium-sulfate (>70 precent Ca + Mg and >50 percent SO4 + Cl) or calcium-magnesium-bicarbonate (>70 percent Ca + Mg and  mHCO3− + 2mCO3−2) carnotite saturation was achieved. If, however, the initial major-ion groundwater composition is sodium-bicarbonate (varying amounts of Na, 40–100 percent Na), calcium-sodium-sulfate, or calcium-magnesium-bicarbonate composition (>70 percent HCO3 + CO3) and following the precipitation of calcite, the concentration of calcium was less than the carbonate alkalinity (2mCa+2 < mHCO3- + 2mCO3−2) carnotite saturation was not achieved. In systems open to CO2, carnotite saturation occurred in most samples in evaporation amounts ranging from 95 percent to 99 percent with the partial pressure of CO2 ranging from 10−3.5 to 10−2.5 atm. Carnotite saturation occurred in a few samples in evaporation amounts ranging from 98 percent to 99 percent with the partial pressure of CO2 equal to 10−2.0 atm. Carnotite saturation did not occur in any groundwater with the system closed

  13. Environmental assessment of the potential effects of aquifer thermal energy storage systems on microorganisms in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, R.J.; Stewart, D.L.

    1988-03-01

    The primary objective of this study was to evaluate the potential environmental effects (both adverse and beneficials) of aquifer thermal energy storage (ATES) technology pertaining to microbial communities indigenous to subsurface environments (i.e., aquifers) and the propagation, movement, and potential release of pathogenic microorganisms (specifically, Legionella) within ATES systems. Seasonal storage of thermal energy in aquifers shows great promise to reduce peak demand; reduce electric utility load problems; contribute to establishing favorable economics for district heating and cooling systems; and reduce pollution from extraction, refining, and combustion of fossil fuels. However, concerns that the widespread implementation of this technology may have adverse effects on biological systems indigeneous to aquifers, as well as help to propagate and release pathogenic organisms that enter thee environments need to be resolved. 101 refs., 2 tabs.

  14. REGIONAL FEATURES OF THE USE OF GROUNDWATER AS A POTENTIAL SOURCE OF THE FORMATION OF THE RADIATION FACTOR

    Directory of Open Access Journals (Sweden)

    E. V. Lisachenko

    2018-01-01

    Full Text Available Underground water is one of the sources of water supply and the most important mineral resources. The enrichment of natural groundwater with radium isotopes is a geochemical regularity, and their use a recognized source of additional exposure to the population and the environment. Forecast resources of groundwater in the territory of the Russian Federation are 869055 thousand m3/day. As of 01.01.2015, 15054 deposits (sections of groundwater have been explored, of which 10556 are in operation. In the federal districts, the volume of extraction and extraction of groundwater varies widely. The percentage of groundwater in domestic and drinking water supply in 35 regions of the Russian Federation ranges from 70 to 100%; in more than 30 regions it exceeds 90%. A whole series of large cities provide water supply through the underground water. Underground waters, depending on the field of application, are divided into drinking, technical, heat power, industrial and medical. The formation of numerous areas with an increased content of natural radionuclides for all types of groundwater is largely determined by the volume of their use. Organized use of groundwater is preceded by special water treatment, where it is possible to form doses of exposure to those above permissible levels established in NRB-99/2009 and the formation of a mass of waste with an increased content of natural radionuclides. In many regions of the country, there is a prospect of a constant increase in the use of all types of groundwater and the creation of new enterprises, which will require monitoring and radiation and hygienic assessment. Particular attention should be paid to the use of associated waters of oil and gas fields that have the highest content of natural radionuclides among groundwaters as a promising source of mineral raw materials.

  15. Field and Laboratory Evaluation of the Potential for Monitored Natural Attenuation of Perchlorate in Groundwater

    Science.gov (United States)

    2007-07-01

    Petroleum hydrocarbons mg/L 1.03 50.3 0.19 PHC as Gasoline µg/L 10,700 224,000 2160 PHC as Diesel Fuel mg/L 0.25 16 ɘ.095 Water Quality Total Organic...Intrinsic Bioremediation . Ground Water 33(2):180-189. Borden, R. C., M. J. Hunt, M. B. Shafer, M. A. Barlaz, 1997a. Environmental Research Brief...and J. Pollock, 2003. Potential for In Situ Bioremediation of Perchlorate in Contaminated Environments. Presented at: In Situ and On- Site

  16. Laboratory evaluation of the potential for in situ treatment of chromate-contaminated groundwater by chemical precipitation

    International Nuclear Information System (INIS)

    Thornton, E.C.; Beck, M.A.; Jurgensmeier, C.A.

    1995-03-01

    The objective of this paper is to present the results of a series of small-scale batch tests performed to assess the effectiveness of chemical precipitation in the remediation of chromate-contaminated groundwater. These tests involved treatment of chromate solutions with ferrous and sulfide ions. In addition, tests were conducted that involved treatment of mixtures of chromate-contaminated groundwater and uncontaminated soil with the ferrous ion. A combination of ferrous sulfate and sodium sulfide was also tested in the groundwater treatment tests, since this approach has been shown to be an efficient method for treating electroplating wastewaters

  17. Evaluation of the potential for artificial ground-water recharge in eastern San Joaquin County, California; Phase 3

    Science.gov (United States)

    Hamlin, S.N.

    1987-01-01

    Infiltration tests were used to evaluate the potential of basin spreading surface water as a means of artificially recharging the aquifer system in eastern San Joaquin County, California. Two infiltration sites near Lockeford and Linden were selected on the basis of information collected during the first two phases of the study. Data from the infiltration tests indicate that the two sites are acceptable for recharge by the basin-spreading method. Infiltration rates ranged between 6.7 and 10.5 ft/day near Lockeford and between 2.6 and 11.2 ft/day near Linden. Interpretation of these data is limited by lack of information on the response of the saturated zone during testing and by the inherent difficulty in extrapolating the results of small-scale tests to larger long-term operations. Lithology is a major factor that controls infiltration rates at the test sites. The unsaturated zone is characterized by heterogeneous layers of coarse- and fine- grained materials. Clay layers of low hydraulic conductivity commonly form discontinuous lenses that may cause a transient perched water table to develop during recharge. Water level measurements from wells screened in the unsaturated zone indicate that the perched water table could reach the land surface after 2 and 5 months of recharge near Lockeford and Linden, respectively. These figures probably represent the minimum time necessary for saturation of the land. Another major factor that affects infiltration rates is the quality of the recharge water, particularly the suspended sediment content. The clogging action of suspended sediment may be minimized by: (1) pretreatment of recharge water in a settling pond, (2) adherence to a routine program of monitoring and maintenance, and (3) proper design of the recharge facility. Other factors that affect infiltration rates include basin excavation technique, basin shape, and maintenance procedures. Efficient operation of the recharge facility requires careful attention to the

  18. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants

    DEFF Research Database (Denmark)

    Boll, Esther Sørensen; Johnsen, Anders R.; Christensen, Jan H.

    2015-01-01

    and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were......-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated...... calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching...

  19. Identification of artificial groundwater recharging zone using a GIS-based fuzzy logic approach: a case study in a coal mine area of the Damodar Valley, India

    Science.gov (United States)

    Tiwari, Ashwani Kumar; Lavy, Muriel; Amanzio, Gianpiero; De Maio, Marina; Singh, Prasoon Kumar; Mahato, Mukesh Kumar

    2017-12-01

    The West Bokaro coalfield is a richest coal-mining belt in the Damodar Valley, India. The extensive mining of the area has resulted in disruption of the groundwater availability in terms of both quantity and quality. This has led to a drinking water crisis, especially during the pre-monsoon period in the West Bokaro coalfield area. The characterization of the hydrogeological system and the artificial recharging of the aquifers might help to better manage the problem of the groundwater-level depletion. For this purpose, seven important hydrogeological factors (water depth, slope, drainage, soil, infiltration, lithology, and landuse) have been considered to define the most suitable locations for artificial groundwater recharging in the mining area. Different thematic maps were prepared from existing maps and data sets, remote-sensing images, and field investigations for identification of the most suitable locations for artificial recharge. Thematic layers for these parameters were prepared, classified, weighted, and integrated into a geographic information system (GIS) environment by means of fuzzy logic. The results of the study indicate that about 29 and 31% of the area are very suitable and suitable for recharging purposes in the West Bokaro coalfield. However, the rest of the area is moderate to unsuitable for recharging due to the ongoing mining and related activities in the study area. The groundwater recharging map of the study area was validated with measured electrical conductivity (EC) values in the groundwater, and it indicated that validation can be accepted for the identification of groundwater recharging sites. These findings are providing useful information for the proper planning and sustainable management of the groundwater resources in the study area.

  20. Model-based assessment of the potential of seasonal aquifer thermal energy storage and recovery as a groundwater ecosystem service for the Brussels-Capital Region

    Science.gov (United States)

    Anibas, Christian; Huysmans, Marijke

    2015-04-01

    Urban areas are characterized by their concentrated demand of energy, applying a high pressure on urban ecosystems including atmosphere, soils and groundwater. In the light of global warming, urbanization and an evolving energy system, it is important to know how urbanized areas can contribute to their own energy demands. One option is to use the possibilities aquifers offer as an ecosystem service (BONTE et al., 2011). If used effectively an improvement in air and groundwater quality is achieved. Additionally, the more efficient distribution of the used energy may also lead to a decrease in primary energy consumption (ZUURBIER, 2013). Therefore, investigations of the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is being conducted. The potential of ATES systems are of special interest for energy demands in high density urban areas because of such infrastructure as office buildings, schools, hospitals and shopping malls. In an open water circuit ATES systems consist of two or more groundwater wells, where in seasonal cycles one subtracts and the other recharges water to the aquifer. Heat pumps use the heat capacity of water for heating or cooling a building. An important limitation of the methodology is the quality of the groundwater used (i.e. precipitation of Fe- or Mn-oxides can decrease the yield). However, ATES systems on the other hand can also improve groundwater quality and groundwater ecosystems. The current knowledge of the potential for ATES systems in the Brussels-Capital Region is based on geological assessments from VITO (2007). The Brussels-Capital Region is divided into a western and eastern section with respect to geology. While the western part has less favorable conditions for ATES, the eastern is composed of the Brussels Sand formation, which is a 20-40 m thick aquifer layer that has the highest potential for ATES systems in the region. By applying groundwater flow and heat

  1. Microbial Community-Level Physiological Profiles (CLPP) and herbicide mineralization potential in groundwater affected by agricultural land use

    DEFF Research Database (Denmark)

    Janniche, Gry Sander; Spliid, Henrik; Albrechtsen, Hans-Jørgen

    2012-01-01

    Diffuse groundwater pollution from agricultural land use may impact the microbial groundwater community, which was investigated as Community-Level Physiological Profiles (CLPP) using EcoPlate™. Water was sampled from seven piezometers and a spring in a small agricultural catchment with diffuse......-galacturonic acid, tween 40, and 4-hydroxy benzoic acid as substrates, whereas none preferred 2-hydroxy benzoic acid, α-d-lactose, d,l-α-glycerol phosphate, α-ketobutyric acid, l-threonine and glycyl-l-glutamic acid. Principal Component Analysis of the CLPP's clustered the most agriculturally affected groundwater...... samples, indicating that the agricultural land use affects the groundwater microbial communities. Furthermore, the ability to mineralize atrazine and isoproturon, which have been used in the catchment, was also associated with this cluster....

  2. Application of {sup 222} Rn as a tracer of groundwater discharge at the coastal zone of Ubatuba, Sao Paulo State, Brazil; Aplicacao de {sup 222} Rn como tracador da descarga de aguas subterraneas na regiao costeira de Ubatuba, Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Joselene de; Farias, Luciana A.; Mazzilli, Barbara P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Dept. de Radiometria Ambiental]. E-mail: jolivei@net.ipen.br; Burnett, William C. [Florida State Univ., Tallahassee, FL (United States); Saraiva, Elisabete de S.B. e; Furtado, Valdenir V. [Sao Paulo Univ., SP (Brazil). Inst. Oceanografico. Dept. de Oceanografia Quimica e Geologica

    2002-07-01

    Submarine groundwater discharge (SGD) and recycled seawater can provide chemical constituents to coastal zone, representing an important material flux pathway from land to sea in some areas. Geochemical tracers, like {sup 222} Rn and {sup 226} Ra, are advantageous for regional-scale assessment of SGD, because their signals represent values integrated through the water column that removes small-scale variations. These radionuclides are usually enriched in groundwater compared to seawater, can be measured at very low concentrations and are conservative. This work reports preliminary results of a study carried out in a series of small embayements of Ubatuba, Sao Paulo State-Brazil, covering latitudes between 23 deg 26{sup '}S and 23 deg 46{sup '}S and longitudes between 45 deg02{sup '}W and 45 deg 11{sup '}W. The main aims of this research were to set up an analytical method to assess {sup 222} Rn and {sup 226} Ra activities in seawater samples and to apply the excess {sup 222} Rn inventories obtained to estimate the submarine groundwater discharge. Measurements made during 2001/2002 included {sup 222} Rn and {sup 226} Ra in seawater, {sup 222} Rn in sediment, seawater and sediment physical properties. (author)

  3. Methods for evaluating potential sources of chloride in surface waters and groundwaters of the conterminous United States

    Science.gov (United States)

    Granato, Gregory E.; DeSimone, Leslie A.; Barbaro, Jeffrey R.; Jeznach, Lillian C.

    2015-09-04

    Chloride exists as a major ion in most natural waters, but many anthropogenic sources are increasing concentrations of chloride in many receiving waters. Although natural concentrations in continental waters can be as high as 200,000 milligrams per liter, chloride concentrations that are suitable for freshwater ecology, human consumption, and agricultural and industrial water uses commonly are on the order of 10 to 1,000 milligrams per liter. “Road salt” frequently is identified as the sole source of anthropogenic chloride, but only about 30 percent of the salt consumed and released to the environment is used for deicing. Furthermore, several studies in Southern States where the use of deicing salt is minimal also show anthropogenic chloride in rising concentrations and in strong correlation to imperviousness and road density. This is because imperviousness and road density also are strongly correlated to population density. The term “road salt” is a misnomer because deicers applied to parking lots, sidewalks, and driveways can be a substantial source of chloride in some catchments because these land covers are comparable to roadways as a percentage of the total impervious area and commonly receive higher salt application rates than some roadways. Other sources of anthropogenic chloride include wastewater, dust control on unpaved roads, fertilizer, animal waste, irrigation, aquaculture, energy production wastes, and landfill leachates. The assumption that rising chloride concentrations in surface water or groundwater is indicative of contamination by deicing chemicals rather than one or more other potential sources may preclude the identification of toxic, carcinogenic, mutagenic, or endocrine-disrupting contaminants that are associated with many sources of elevated chloride concentrations. Once the sources of anthropogenic chloride in an area of interest have been identified and measured, water and solute budgets can be estimated to guide decisionmakers to

  4. Near Surface Geophysical Investigations of Potential Direct Recharge Zones in the Biscayne Aquifer within Everglades National Park, Florida.

    Science.gov (United States)

    Mount, G.; Comas, X.

    2017-12-01

    The karstic Miami Limestone of the Biscayne aquifer is characterized as having water flow that is controlled by the presence of dissolution enhanced porosity and mega-porous features. The dissolution features and other high porosity areas create horizontal preferential flow paths and high rates of ground water velocity, which may not be accurately conceptualized in groundwater flow models. In addition, recent research suggests the presence of numerous vertical dissolution features across Everglades National Park at Long Pine Key Trail, that may act as areas of direct recharge to the aquifer. These vertical features have been identified through ground penetrating radar (GPR) surveys as areas of velocity pull-down which have been modeled to have porosity values higher than the surrounding Miami Limestone. As climate change may induce larger and longer temporal variability between wet and dry times in the Everglades, a more comprehensive understanding of preferential flow pathways from the surface to the aquifer would be a great benefit to modelers and planners. This research utilizes near surface geophysical techniques, such as GPR, to identify these vertical dissolution features and then estimate the spatial variability of porosity using petrophysical models. GPR transects that were collected for several kilometers along the Long Pine Key Trail, show numerous pull down areas that correspond to dissolution enhanced porosity zones within the Miami Limestone. Additional 3D GPR surveys have attempted to delineate the boundaries of these features to elucidate their geometry for future modelling studies. We demonstrate the ability of near surface geophysics and petrophysical models to identify dissolution enhanced porosity in shallow karstic limestones to better understand areas that may act as zones of direct recharge into the Biscayne Aquifer.

  5. A geophysical potential field study to image the Makran subduction zone in SE of Iran

    Science.gov (United States)

    Abedi, Maysam; Bahroudi, Abbas

    2016-10-01

    The Makran subduction wedge as one of the largest subduction complexes has been forming due to the Arabian oceanic lithosphere subducting beneath the Lut and the Afghan rigid block microplates. To better visualize the subducting oceanic crust in this region, a geophysical model of magnetic susceptibility from an airborne magnetic survey (line spacing about 7.5 km) over the Makran zone located at southeast of Iran is created to image various structural units in Iran plate. The constructed geophysical model from the 3D inverse modeling of the airborne magnetic data indicates a thin subducting slab to the north of the Makran structural zone. It is demonstrated that the thickness of sedimentary units varies approximately at an interval of 7.5-11 km from north to south of this zone in the Iranian plate, meanwhile the curie depth is also estimated approximately basement, while such intensity reduces over the Makran. The directional derivatives of the magnetic field data have subtle changes in the Makran, but strongly increase in the Jazmurian by enhancing and separating different structural boundaries in this region. In addition, the density variations of the subsurface geological layers were determined by 3D inversion of the ground-based gravity data over the whole study area, where the constructed density model was in good agreement with the magnetic one. According to the outputs of the magnetic susceptibility and the density contrast, the Arabian plate subducts to the north under the Eurasia with a very low dip angle in the Makran structural zone.

  6. Hot spots and hot moments in riparian zones: Potential for improved water quality management

    Science.gov (United States)

    Philippe Vidon; Craig Allan; Douglas Burns; Tim P. Duval; Noel Gurwick; Shreeram Inamdar; Richard Lowrance; Judy Okay; Durelle Scott; Stephen Sebestyen

    2010-01-01

    Biogeochemical and hydrological processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. These heterogeneous processes have recently been conceptualized as "hot spots and moments" of retention, degradation, or production. Nevertheless, studies investigating...

  7. The potential application of social impact assessment in integrated coastal zone management

    NARCIS (Netherlands)

    Vanclay, Frank

    2012-01-01

    Integrated coastal zone management (ICZM) would be significantly enhanced if there was greater connection to the field of social impact assessment (SIA). SIA is the process of managing the social issues of planned interventions (projects, policies, plans, and programs). SIA can also be used to

  8. Organization A Comprehensive System Of Insurance Coverage In The Potential Chemical And Biological Contamination Zone In Regions

    Directory of Open Access Journals (Sweden)

    Nina Vladimirovna Zaytseva

    2014-12-01

    Full Text Available The article provides a scientific rationale for an integrated approach to the provision of insurance coverage in the potential chemical and biological contamination zone. The following modern forms of chemical safety in the Russian Federation were considered: state reserve’s system, target program financing, state social insurance. The separate issue tackles the obligatory civil liability insurance for owners of dangerous objects. For improvement of the existing insurance protection system against emergency situations, risks were analyzed (shared on exogenous and endogenous. Among the exogenous risks including natural and climatic conditions of a region, its geographical arrangement, economic specialization, the seismic and terrorist risks were chosen and approaches to its solution were suggested. In endogenous risks’ group, the special focus is on wear and tear and obsolescence of hazardous chemical and biological object’s fixed assets. In case of high risk of an incident, it is suggested to increase in extent of insurance protection through self-insurance, a mutual insurance in the form of the organization of societies of a mutual insurance or the self-regulating organizations, and also development of voluntary insurance of a civil liability, both the owner of hazardous object, and regions of the Russian Federation and municipalities. The model of insurance coverage in the potential chemical and biological contamination zone is based on a differentiated approach to the danger level of the area. A matrix of adequate forms and types of insurance (required for insurance coverage of the population in the potential chemical and biological contamination zone was constructed. Proposed health risk management toolkit in the potential chemical and biological contamination zone will allow to use financial resources for chemical and biological safety in the regions more efficiently.

  9. Simulated groundwater flow in the Ogallala and Arikaree aquifers, Rosebud Indian Reservation area, South Dakota - Revisions with data through water year 2008 and simulations of potential future scenarios

    Science.gov (United States)

    Long, Andrew J.; Putnam, Larry D.

    2010-01-01

    The Ogallala and Arikaree aquifers are important water resources in the Rosebud Indian Reservation area and are used extensively for irrigation, municipal, and domestic water supplies. Drought or increased withdrawals from the Ogallala and Arikaree aquifers in the Rosebud Indian Reservation area have the potential to affect water levels in these aquifers. This report documents revisions and recalibration of a previously published three-dimensional, numerical groundwater-flow model for this area. Data for a 30-year period (water years 1979 through 2008) were used in steady-state and transient numerical simulations of groundwater flow. In the revised model, revisions include (1) extension of the transient calibration period by 10 years, (2) the use of inverse modeling for steady-state calibration, (3) model calibration to base flow for an additional four surface-water drainage basins, (4) improved estimation of transient aquifer recharge, (5) improved delineation of vegetation types, and (6) reduced cell size near large capacity water-supply wells. In addition, potential future scenarios were simulated to assess the potential effects of drought and increased groundwater withdrawals.The model comprised two layers: the upper layer represented the Ogallala aquifer and the lower layer represented the Arikaree aquifer. The model’s grid had 168 rows and 202 columns, most of which were 1,640 feet (500 meters) wide, with narrower rows and columns near large water-supply wells. Recharge to the Ogallala and Arikaree aquifers occurs from precipitation on the outcrop areas. The average recharge rates used for the steady-state simulation were 2.91 and 1.45 inches per year for the Ogallala aquifer and Arikaree aquifer, respectively, for a total rate of 255.4 cubic feet per second (ft3/s). Discharge from the aquifers occurs through evapotranspiration, discharge to streams as base flow and spring flow, and well withdrawals. Discharge rates for the steady-state simulation were 171

  10. Characterization of the arsenite oxidizer Aliihoeflea sp. strain 2WW and its potential application in the removal of arsenic from groundwater in combination with Pf-ferritin.

    Science.gov (United States)

    Corsini, Anna; Colombo, Milena; Muyzer, Gerard; Cavalca, Lucia

    2015-09-01

    A heterotrophic arsenite-oxidizing bacterium, strain 2WW, was isolated from a biofilter treating arsenic-rich groundwater. Comparative analysis of 16S rRNA gene sequences showed that it was closely related (98.7 %) to the alphaproteobacterium Aliihoeflea aesturari strain N8(T). However, it was physiologically different by its ability to grow at relatively low substrate concentrations, low temperatures and by its ability to oxidize arsenite. Here we describe the physiological features of strain 2WW and compare these to its most closely related relative, A. aestuari strain N8(T). In addition, we tested its efficiency to remove arsenic from groundwater in combination with Pf-ferritin. Strain 2WW oxidized arsenite to arsenate between pH 5.0 and 8.0, and from 4 to 30 °C. When the strain was used in combination with a Pf-ferritin-based material for arsenic removal from natural groundwater, the removal efficiency was significantly higher (73 %) than for Pf-ferritin alone (64 %). These results showed that arsenite oxidation by strain 2WW combined with Pf-ferritin-based material has a potential in arsenic removal from contaminated groundwater.

  11. Evaluation of the potential impact of climate changes on groundwater recharge in Karkheh river basin (Khuzestan, Iran)

    Science.gov (United States)

    Abrishamchi, A.; Beigi, E.; Tajrishy, M.; Abrishamchi, A.

    2009-12-01

    Groundwater is an important natural resource for human beings and ecosystems, especially in arid semi arid regions with scarce water resources and high climate variability. This vital resource is under stress in terms of both quantity and quality due to increased demands as well as the drought. Wise groundwater management requires vulnerability and susceptibility assessment of groundwater resources to natural and anthropogenic phenomena such as drought, over-abstraction and quality deterioration both in the current climatic situation and in the context of climate change. There is enough evidence that climate change is expected to affect all elements of hydrologic cycle and have negative effects on water resources due to increased variability in extreme hydrologic events of droughts and floods. .In this study impact of climate change on groundwater recharge in Karkheh river basin in province of Khuzestan, Iran, has been investigated using a physically-based methodology that can be used for predicting both temporal and spatial varying groundwater recharge. To ensure the sustainability of the land and water resources developments, assessment of the possible impacts of climate change on hydrology and water resources in the basin is necessary. Quantifying groundwater recharge is essential for management of groundwater resources. Recharge was estimated by using the hydrological evaluation of landfill performance (HELP3) water budget model. Model’s parameters were calibrated and validated using observational data in 1990-1998. The impact of climate change was modeled using downscaled precipitation and temperature from runs of CGCM2 model. These data were derived from two scenarios, A2 and B2 for three periods: 2010-2039, 2040-2069, and 2070-2099. Results of the study indicate that due to global warming evapotranspiration rates will increase and winter-precipitation will fall, spring-snowmelt will shift toward winter and consequently it will cause recharge to increase

  12. Alteration zone mapping for detecting potential mineralized areas in Kaladawan of north altyn tagh using ASTER data

    International Nuclear Information System (INIS)

    Yong-gui, Zhou; Bai-lin, Chen; Xing-tong, Chen; Zheng-le, Chen

    2014-01-01

    The Kaladawan area has been found developing intense hydrothermal altered rocks associated with mineralized area such as Kaladaban Pb-Zn deposit, A-bei Ag-Pb depositduring earlier geological investigations.Yet the sparse vegetation cover and excellent bedrock exposure make it a suitable place for the use of remote sensing methods for lithological mapping. ASTER data has been used in this study to identify alteration zones, and then to detect potential mineralized areas. Band ratio and PCA procedures were applied based on the analysis of spectral properties of typical alteration minerals. Band 4/2 and mineralogic indices proposed by Ninomiya were designed to map the distribution of Fe-oxides and alteration zones. Selected bands combinations were transformed in a PCA procedure to map the Al-OH, Mg-OH, CO 3 2− and Fe-oxides altered minerals. The analysis focused on the spatial distribution of hydrothermal altered minerals. Band ratio result images including both Fe-oxides and mineralogic indices show high-level similarity with the PCA transform procedure. They both show intense hydrothermal alteration zone in Kaladaban,west Kaladawan and A-bei area. Hence, these areas are considered to have potential for further mineralogic exploration. The results were validated by field work in the Kaladaban and west Kaladawan area,indicating that this method can be a useful tool for detecting potential mineralization area in Kaladawan and similar areas elsewhere

  13. Groundwater Hydrology and Chemistry in and near an Emulsified Vegetable-Oil Injection Zone, Solid Waste Management Unit 17, Naval Weapons Station Charleston, North Charleston, South Carolina, 2004-2009

    Science.gov (United States)

    Vroblesky, Don A.; Petkewich, Matthew D.; Lowery, Mark A.; Conlon, Kevin J.; Casey, Clifton C.

    2010-01-01

    The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated the hydrology and groundwater chemistry in the vicinity of an emulsified vegetable-oil injection zone at Solid Waste Management Unit (SWMU) 17, Naval Weapons Station Charleston, North Charleston, South Carolina. In May 2004, Solutions-IES initiated a Phase-I pilot-scale treatability study at SWMU17 involving the injection of an edible oil emulsion into the aquifer near wells 17PS-01, 17PS-02, and 17PS-03 to