WorldWideScience

Sample records for alluvial plains

  1. Level IV Ecoregions of the Mississippi Alluvial Plain

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in...

  2. Level III Ecoregions of the Mississippi Alluvial Plain

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ecoregions for the Mississippi Alluvial Plain were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in...

  3. Lithium isotope behaviour during weathering in the Ganges Alluvial Plain

    Science.gov (United States)

    Pogge von Strandmann, Philip A. E.; Frings, Patrick J.; Murphy, Melissa J.

    2017-02-01

    The Ganges river system is responsible for the transportation of a large flux of dissolved materials derived from Himalayan weathering to the oceans. Silicate weathering-driven cooling resulting from uplift of the Himalayas has been proposed to be a key player in Cenozoic climate variation. This study has analysed Li isotope (δ7Li) ratios from over 50 Ganges river waters and sediments, in order to trace silicate weathering processes. Sediments have δ7Li of ∼0‰, identical to bulk continental crust, however suspended sediment depth profiles do not display variations associated with grain size that have been observed in other large river systems. Dissolved δ7Li are low (∼11‰) in the Ganges headwaters, but reach a constant value of 21 ± 1.6‰ within a relatively short distance downstream, which is then maintained for almost 2000 km to the Ganges mouth. Given that Li isotopes are controlled by the ratio of primary mineral dissolution to secondary mineral formation, this suggests that the Ganges floodplain is at steady-state in terms of these processes for most of its length. Low δ7Li in the mountainous regions suggest silicate weathering is therefore at its most congruent where uplift and fresh silicate exposure rates are high. However, there is no correlation between δ7Li and the silicate weathering rate in these rivers, suggesting that Li isotopes cannot be used as a weathering-rate tracer, although they do inform on weathering congruency and intensity. The close-to-constant δ7Li values for the final 2000 km of Ganges flow also suggest that once the size of the alluvial plain reached more than ∼500 km (the flow distance after which riverine δ7Li stops varying), the Ganges exerted little influence on the changing Cenozoic seawater δ7Li, because riverine δ7Li attained a near steady-state composition.

  4. Rainfall-induced nutrient losses from manure-fertilized farmland in an alluvial plain.

    Science.gov (United States)

    Wang, Yiyao; Li, Huaizheng; Xu, Zuxin

    2016-01-01

    Nutrient transport and loss in farmlands are affected by factors such as land cover, fertilization, soil type, rainfall, and management practices. We investigated the temporal and spatial changes in macronutrient transport and loss after fertilization and precipitation in manure-fertilized eggplant farmland in an alluvial plain. Upon adding topical fertilizer, concentrations of most nutrients in runoff and groundwater increased, and nitrogen runoff increased from 22.11 to 35.81 kg/ha, although eggplant yield did not increase correspondingly. Incorporation of fertilizer by plowing reduced nutrient losses (nitrogen runoff/fertilizer decreased from 18.40 to 12.29 %). Measurements taken along the nutrient transport route (runoff, drainage ditch, groundwater, river water, and finally rainfall) revealed that concentrations of most nutrients declined at each stage. Nutrient characteristics varied by transport, and the forms of nitrogen and phosphorus differed greatly between runoff and groundwater (nitrate/nitrogen in runoff was ~43.49 %, while in groundwater ~5.41 %). Most nutrient concentrations in runoff decreased greatly during the planting season (total nitrogen decreased from 62.25 to 4.17 mg/L), correlated positively with temperature and stage of plant growth, but little temporal change was observed in groundwater. This field investigation during one planting season exemplifies the basic principles of nutrient loss and transport from manure-fertilized farmland in an alluvial plain.

  5. Discharge estimation from planform characters of the Shedhi River, Gujarat alluvial plain: Present and past

    Indian Academy of Sciences (India)

    Alpa Sridhar

    2007-08-01

    In the absence of long-term hydrologic and streamflow records an understanding of river morphology (present and past) can help delineate changes in magnitudes of water and sediment discharges. The relict drainage system of Gujarat alluvial plain provides an opportunity to reconstruct the palaeochannel morphology-related discharge estimations. In this paper, based on the geomorphological evidence and channel geometry, an attempt has been made to reconstruct the palaeohydrological condition in the Shedhi River during the Holocene. A comparison of the present day channel of the Shedhi River with that of its palaeo counterpart reveals that the former was carrying much higher bankfull discharge (∼5500m3s−1) as compared to the present (∼200m3s−1). This is attributed to a larger drainage area and enhanced precipitation in the Shedhi River basin.

  6. Multilevel approach to the geomorphological setting of an alluvial plain in the Alpine environment

    Science.gov (United States)

    Minciotti, Nancy A.; Brivio, Pietro A.; Zilioli, Eugenio

    1995-11-01

    This paper presents an integrated use of cartography and remote sensing imagery supplied by satellite and aircraft to study the geomorphological aspects of an alluvial plain for archaeological purposes. The study area is located at the confluence of the Valtellina (Adda River) and Lower Mera River valleys in northern Italy. Landsat data and aerial photographs were used to study the partial filling of the Lake Como lacustrine basin resulting from the progradation of the Adda River delta. Different soil humidity content, related to variable grain size of the alluvial deposits is an indicator of ancient river beds which were formed in this area before the nineteenth century artificial rectification of the River Adda's final stretch. Profiles coincident with geological sections gained by geophysical sounding were performed on the remote sensing imagery to verify eventual correspondence of depositional features with different analysis techniques. The integration of remote sensing multilevel data with cartography and archaeological evidences has been useful for the assessment of the paleoenvironment which conditioned human settlements.

  7. Soil temperature prediction from air temperature for alluvial soils in lower Indo-Gangetic plain

    Science.gov (United States)

    Barman, D.; Kundu, D. K.; Pal, Soumen; Pal, Susanto; Chakraborty, A. K.; Jha, A. K.; Mazumdar, S. P.; Saha, R.; Bhattacharyya, P.

    2017-01-01

    Soil temperature is an important factor in biogeochemical processes. On-site monitoring of soil temperature is limited in spatiotemporal scale as compared to air temperature data inventories due to various management difficulties. Therefore, empirical models were developed by taking 30-year long-term (1985-2014) air and soil temperature data for prediction of soil temperatures at three depths (5, 15, 30 cm) in morning (0636 Indian standard time) and afternoon (1336 Indian standard time) for alluvial soils in lower Indo-Gangetic plain. At 5 cm depth, power and exponential regression models were best fitted for daily data in morning and afternoon, respectively, but it was reverse at 15 cm. However, at 30 cm, exponential models were best fitted for both the times. Regression analysis revealed that in morning for all three depths and in afternoon for 30 cm depth, soil temperatures (daily, weekly, and monthly) could be predicted more efficiently with the help of corresponding mean air temperature than that of maximum and minimum. However, in afternoon, prediction of soil temperature at 5 and 15 cm depths were more precised for all the time intervals when maximum air temperature was used, except for weekly soil temperature at 15 cm, where the use of mean air temperature gave better prediction.

  8. Land use change and its driving forces in alluvial-plain oasis

    Science.gov (United States)

    Xiao, Luxiang; Zhang, Zengxiang; Chen, Xi; Luo, Geping; Wen, Qingke

    2007-11-01

    Land use change and its driving factors are hot topics of global change research, and also important topics of sustainable development. This paper selected a small area in alluvial plain oasis in Xinjiang Autonomous region of China as the study area. Using Landsat TM data of 1987, 1998 and 2004, the dynamic process of the spatial-temporal characteristics of land use changes were analyzed to improve understanding and to find the driving forces of land use changes so that sustainable land utilization could be practiced. During the 17 years salt-alkali tolerant cropland, cereal cropland, vegetable-fruit land, and shrubbery, had decreased remarkably by 78.59%, 85.95%, 92.13%, 68.43%, respectively. Cotton-liquorice land, grape-hop land, planted forest, residential area in town, residential area in village, and saline-alkaline field had increased dramatically. The increased percentage received the value of 2432.11%, 10103.18%, 889.91%, 222.45%, 96.00%, 44.18%, respectively. By the logistic regression, the main driving factors were derived for each land use type. The advance of technology (fertilizer input, irrigation quota, and animal labor et al.) and market (unit are yield net) were the main driving factors. Policy, in a higher level, influenced the land use dynamics for all the land use changes.

  9. Deducing Weathering Processes Using Silicon Isotopes in the Ganges Alluvial Plain, India

    Science.gov (United States)

    Frings, P.; De La Rocha, C. L.; Fontorbe, G.; Chakrapani, G.; Clymans, W.; Conley, D. J.

    2014-12-01

    The Ganges Alluvial Plain ('GAP') is the sedimentary infill of the foreland basin created during Himalayan orogeny. Freshly eroded material from the Himalaya and southern cratonic tributaries is deposited into a system with long water-sediment interaction times, creating potential for further generation of river weathering fluxes. To quantify weathering processes in the GAP, 51 sites including all major tributaries were sampled in a September 2013 campaign and analysed for major and minor ions, Ge/Si ratios and δ30Si, δ13C and δ18O. Net dissolved Si (DSi) and major cation yields are 2 to 5 times lower in the GAP than the Himalaya, and at a whole basin scale approximate the global average, indicating that the plain apparently moderates the efficiency of Himalayan weathering rates. Mainstem δ30Si spans 0.81 to 1.93‰ (see figure) and gives the impression of a system buffered to moderate DSi and δ30Si. Ge/Si ratios (µmol/mol) are higher than expected in the Himalaya (>3), reflecting input of Ge-enriched water from hot springs, and decline to ~1.4 in the GAP. For the Himalayan sourced rivers, δ30Si increases with distance from the Himalayan front, and can not be explained entirely by conservative mixing with higher δ30Si peninsular and GAP streams. To a first degree, the δ30Si data suggest incorporation of Si into secondary minerals as the key fractionating process, and that this occurs both in situ during initial weathering and progressively in the GAP. Partitioning of solutes between sources is complicated in the GAP. Consistent with previous work, carbonate weathering dominates the ion fluxes, but with substantial contributions from saline/alkaline soil salts, the chlorination of wastewater and highly variable rainfall chemistry. Due to these contributions, precisely inferring the input from silicate weathering is difficult. We introduce a novel method to infer silicate-weathering rates that exploits the fractionation of Si during clay formation to account

  10. Tectonic controls on the geomorphic evolution of alluvial fans in the Piedmont Zone of Ganga Plain, Uttarakhand, India

    Indian Academy of Sciences (India)

    Pradeep K Goswami; Charu C Pant; Shefali Pandey

    2009-06-01

    The Piedmont Zone is the least studied part of the Ganga Plain.The northern limit of the Piedmont Zone is defined by the Himalayan Frontal Thrust (HFT)along which the Himalaya is being thrust over the alluvium of the Ganga Plain.Interpretation of satellite imagery,Digital Terrain Models (DTMs)and field data has helped in the identification and mapping of various morpho-tectonic features in the densely forested and cultivated Piedmont Zone in the Kumaun region of the Uttarakhand state of India.The Piedmont Zone has formed as a result of coalescing alluvial fans,alluvial aprons and talus deposits.The fans have differential morphologies and aggradation processes within a common climatic zone and similar litho-tectonic setting of the catchment area. Morphotectonic analysis reveals that the fan morphologies and aggradation processes in the area are mainly controlled by the ongoing tectonic activities.Such activities along the HFT and transverse faults have controlled the accommodation space by causing differential subsidence of the basin,and aggradation processes by causing channel migration,channel incision and shifting of depocentres.The active tectonic movements have further modified the landscape of the area in the form of tilted alluvial fan,gravel ridges,terraces and uplifted gravels.

  11. Soil Moisture and Turgidity of Selected Robusta Coffee Clones on Alluvial Plain with Seasonal Rainfall Pattern

    Directory of Open Access Journals (Sweden)

    Rudy Erwiyono

    2005-08-01

    Full Text Available Observation on the seasonal variations of hydrological condition and turgidity of selected Robusta coffee clones has been carried out in Kaliwining Experimental Station, Indonesian Coffee and Cocoa Research Institute in Jember. The aim was to evaluate the effect of hydrological variation on the coffee plants and the degree of soil moisture effect on plant performance. Experimental site overlays on alluvial plain, + 45 m a.s.l., 8o 15’ South with D rainfall type. Observation was conducted by survey method at the experimental plots of organic fertilizer and nitogen treatments on selected Robusta coffee clones derived from rooted cuttings, i.e. BP 436, BP 42, BP 936 and BP 358. Observation was only conducted at the experimental blocks of organic matter trials of 20 l/tree/year at nitrogen (Urea application of locally recommanded rate during the subsequent years of 1999 to 2001. Parameters observed included plant turgidity and soil moisture content of three different depths, i.e. 0—20, 20—40 and 40—60 cm and the weather. Observation was carried out in five replicates designed as blocks of barn manure treatment and N-fertilizer of recommended rate as basal fertilizer. The results showed that meteorological condition and soil moisture of experimental site through the years have seasonal patterns following the seasonal pattern of rainfall. Compared to other meteorological characteristics, relative humidity dominantly determined evaporation and plant turgidity. Plant turgi-dity was not only determined by soil moisture condition, but also atmospheric demand. When relative humidity (RH was relatively high, plant turgidity was relatively stable although soil moisture of surface layers was very low, and the reversal when soil moisture content was high plant turgidity was controlled by atmospheric demand (relative humidity. With a 3—4 dry month period, relative turgidity of the coffee plants was relatively stable above 82%, except when soil

  12. Spatial pattern of soil organic carbon in desert grasslands of the diluvial-alluvial plains of northern Qilian Mountains

    Institute of Scientific and Technical Information of China (English)

    Rong YANG; YongZhong SU; Min WANG; Tao WANG; Xiao YANG; GuiPing FAN; TianChang WU

    2014-01-01

    The soil properties in arid ecosystems are important determinants of vegetation distribution patterns. Soil organic carbon (SOC) content, which is closely related to soil types and the holding capacities of soil water and nutrients, exhibits complex variability in arid desert grasslands;thus, it is essentially an impact factor for the distri-bution pattern of desert grasslands. In the present study, an investigation was conducted to estimate the spatial pattern of SOC content in desert grasslands and the association with environmental factors in the diluvial-alluvial plains of northern Qilian Mountains. The results showed that the mean values of SOC ranged from 2.76 to 5.80 g/kg in the soil profiles, and decreased with soil depths. The coefficients of variation (CV) of the SOC were high (ranging from 48.83%to 94.67%), which indicated a strong spatial variability. SOC in the desert grasslands of the study re-gion presented a regular spatial distribution, which increased gradually from the northwest to the southeast. The SOC distribution had a pattern linked to elevation, which may be related to the gradient of climate conditions. Soil type and plant community significantly affected the SOC. The SOC had a significant positive relationship with soil moisture (P<0.05);whereas, it had a more significant negative relationship with the soil bulk density (BD) (P<0.01). However, a number of the variations in the SOC could be explained not by the environmental factors involved in this analysis, but rather other factors (such as grazing activity and landscape). The results provide important references for soil carbon storage estimation in this study region. In addition, the SOC association with environmental variables also provides a basis for a sustainable use of the limited grassland resources in the diluvial-alluvial plains of north-ern Qilian Mountains.

  13. Ground-Water Resource Assessment in the Rio Grande de Manati Alluvial Plain, Rio Arriba Saliente Area, Puerto Rico

    Science.gov (United States)

    Torres-Gonzalez, Sigfredo; Gómez-Gómez, Fernando; Warne, Andrew G.

    2002-01-01

    The alluvial aquifer within a 160-acre area of the Rio Grande de Manati alluvial plain was investigated to evaluate its potential as a water-supply source for the Barrios Rio Arriba Saliente and Pugnado Afuera, municipio of Manati, Puerto Rico. Analysis of well boring samples and the results of electric resistivity surveys indicate that the average thickness of the unconsolidated alluvial deposits in the study area is about 100 to 110 feet. The alluvium is a mixture of sand and gravel, which generally has a porosity of 0.2 to 0.35. Short-duration pump tests in small-diameter piezometers indicate that the alluvial aquifer has a hydraulic conductivity of about 200 feet per day and a transmissivity of about 7,900 feet squared per day. Analyses of water levels in piezometers, combined with stage measurements at a series of surveyed reference points along the Rio Grande de Manati channel, indicate that the water-table gradient in the alluvial aquifer is about 0.001, and that ground-water flow is generally from south to north, in the general direction of river flow. The water-table data indicate that the Rio Grande de Manati is the principal source of ground-water recharge to the alluvial aquifer in the study area. Because base flow for the Rio Grande de Manati is usually greater than 44 cubic feet per second, a continuous withdrawal rate of 0.5 to 1.0 cubic foot per second (225 to 450 gallons per minute) from a production well is possible. Chemical analysis of a ground-water sample indicates that the alluvial aquifer water meets U.S. Environmental Protection Agency secondary standards for selected constituents. Bacteriological analysis of ground-water samples indicates that the ground water contains little or no fecal coliform or fecal streptococcus bacteria. Although long-term data from upstream of the study area indicate high levels of fecal coliform and fecal streptococcus prior to 1996, bacteriological analyses of Rio Grande de Manati water samples obtained during

  14. Behavior of boundary layer ozone and its precursors over a great alluvial plain of the world: Indo-Gangetic Plains

    Science.gov (United States)

    Beig, G.; Ali, K.

    2006-12-01

    We investigate the special behavior in the distribution of boundary layer ozone and its precursors over world's most extensive tract of uninterrupted alluvium and intensively farmed zones situated in the foothills of Himalayas as major river basin, known as Indo-Gangetic Plains (IGP). The study makes use of a Chemistry-Transport Model forced with dynamical fields and new emission inventories of pollutants established for 2001. It is found that the IGP region is highly vulnerable to human induced pollutant emissions due to conducive synoptic weather pattern which make it a source regions of ozone precursors within which these tracers remain confined and reinforce photochemical production of ozone. In addition, the continental tropical convergence zone and long range transport play a vital role. As a result, elevated levels of ozone concentration (maximum up to 80 ppbv) and its precursors with cellular structure of spatial variation with large seasonality are noticed.

  15. Simulation of Groundwater Conditions in The Alluvial Plains of The Taihang Mountains of The North China Plain

    Science.gov (United States)

    Shu, Y.; Stisen, S.; Jensen, K. H.; Villholth, K. G.; Sandholt, I.; Lei, Y.

    2009-12-01

    The hydrological model, MIKE SHE, has been applied to the Hebei province of the North China Plain to examine the components of the groundwater balance and to assess the groundwater resources. The model simulates the spatial and temporal distribution of recharge by taking into consideration the spatial patterns of soil characteristics, land use and irrigation. Recharge is the most important input to the groundwater system while groundwater abstraction for irrigation is the dominant output from the system. The model was auto-calibrated against daily observations of groundwater heads from a number of wells spread across the region and actual evapotranspiration measured at an agricultural station the period 1996-2002. The model simulations compared well with observations and reasonable values were obtained for both root mean square error (RMSE) and correlation coefficient (R). The model analysis documented that groundwater tables in the region are subject to sharp declines due to heavy overexploitation of the groundwater resources by irrigation. The calibrated model was subsequently used for scenario simulations of the effect of different cropping patterns. The results showed that the crop rotation irrigated winter wheat and summer maize has the most significant impact on groundwater mining as irrigation requirements for winter wheat are extensive. Currently this is the most widespread crop rotation in North China Plain. In contract, the cultivation pattern of summer crop and winter fallow, like winter fallow and sweet potato, winter fallow and cotton, winter fallow and millet, and winter fallow and summer maize, cause less groundwater mining and some also can reverse water tables declining. The scenario simulations suggest that conversion of the crop rotations into rainfed summer crop and winter fallow is a potential solution for reversing the current decline in groundwater tables.

  16. Geomorphologic, stratigraphic and sedimentologic evidences of tectonic activity in Sone–Ganga alluvial tract in Middle Ganga Plain, India

    Indian Academy of Sciences (India)

    Sudarsan Sahu; Dipankar Saha

    2014-08-01

    The basement of the Ganga basin in the Himalayan foreland is criss-crossed by several faults, dividing the basin into several sub-blocks forming horsts, grabens, or half-grabens. Tectonic perturbations along basement faults have affected the fluvial regime and extent of sediment fill in different parts of the basin during Late Quaternary. The East Patna Fault (EPF) and the West Patna Fault (WPF), located in Sone–Ganga alluvial tract in the southern marginal parts of Middle Ganga Plain (MGP), have remained tectonically active. The EPF particularly has acted significantly and influenced in evolving the geomorphological landscape and the stratigraphic architecture of the area. The block bounded by the two faults has earlier been considered as a single entity, constituting a half-graben. The present investigation (by morpho-stratigraphic and sedimentologic means) has revealed the existence of yet another fault within the half-graben, referred to as Bishunpur–Khagaul Fault (BKF). Many of the long profile morphological characters (e.g., knick-zone, low width–depth ratio) of the Sone River at its lower reaches can be ascribed to local structural deformation along BKF. These basement faults in MGP lie parallel to each other in NE–SW direction.

  17. Effect of Long-Term Fertilization on Organic Nitrogen Forms in a Calcareous Alluvial Soil on the North China Plain

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to illustrate the change of nitrogen (N) supply capacity after long-term application of manure and chemical fertilizer, as well as to properly manage soil fertility through fertilizer application under the soil-climatic conditions of the North China Plain, organic N forms were quantified in the topsoil with different manure and chemical fertilizer treatments in a 15-year fertilizer experiment in a Chinese calcareous alluvial soil Soil total N (TN) and various organic N forms were significantly influenced by long-term application of chemical fertilizer and manure. TN, total hydrolysable N, acid-insoluble N, amino acid N and ammonium N in the soil increased significantly (P < 0.05) with increasing manure and fertilizer N rates, but were not influenced by increasing P rates. Also, application of manure or N fertilizer or P fertilizer did not significantly influence either the quantity of amino sugar N or its proportion of TN. Application of manure significantly increased (P < 0.05) hydrolysable unknown N, but adding N or P did not. In addition, application of manure or N fertilizer or P fertilizer did not significantly influence the proportions of different soil organic N forms.

  18. Liquefaction record of the great 1934 earthquake predecessors from the north Bihar alluvial plains of India

    Science.gov (United States)

    Rajendran, C. P.; John, Biju; Rajendran, Kusala; Sanwal, Jaishri

    2016-07-01

    The great 1934 Himalayan earthquake of moment magnitude (Mw) 8.1 generated a large zone of ground failure and liquefaction in north Bihar, India, in addition to the earthquakes of 1833 (Mw ~7.7) and 1988 (Mw 6.7) that have also impacted this region. Here, we present the results of paleoliquefaction investigations from four sites in the plains of north Bihar and one in eastern Uttar Pradesh. The liquefaction features generated by successive earthquakes were dated at AD 829-971, 886-1090, 907-1181, 1130-1376, 1112-1572, 1492-1672, 1733-1839, and 1814-1854. One of the liquefaction events dated at AD 829-971, 886-1090, and 907-1181 may correlate with the great earthquake of AD ~1100, recognized in an earlier study from the sections across the frontal thrust in central eastern Nepal. Two late medieval liquefaction episodes of AD 1130-1376 and 1492-1672 were also exposed in our sites. The sedimentary sections also revealed sandblows that can be attributed to the 1833 earthquake, a lesser magnitude event compared to the 1934. Liquefactions triggered by the 1934 and 1988 earthquakes were evident within the topmost level in some sections. The available data lead us to conjecture that a series of temporally close spaced earthquakes of both strong and large types, not including the infrequent great earthquakes like the 1934, have affected the Bihar Plains during the last 1500 years with a combined recurrence interval of 124 ± 63 years.

  19. Use of U-series nuclides to constrain sediments transfer-times in the alluvial plains: example of the Ganges and Bramaputra river system.

    Science.gov (United States)

    Chabaux, François; Granet, Mathieu; Blaes, Estelle; Stille, Peter; France-Lanord, Christian; Dosseto, Antony

    2010-05-01

    U-series nuclides have the potential to bring important information on the transfer time of sediments in the alluvial plains. This is a consequence of the dual property of these nuclides 1) to be fractionated during physical denudation and chemical weathering processes and 2) to have radioactive decay periods of the same order of magnitude as the time-scales of these processes (e.g. Chabaux et al., 2003b, 2008). We have illustrated such a potential with the analysis of U-series disequilibria in sediments collected in the Ganges and Bramaputra river basin. The approach relies on the analysis of U-series in river sediments collected along the streams. Indeed, as illustrated in Granet et al. (2007), in large alluvial plains where sediments are only transferred and not affected by additional inputs of new weathering products from fresh rocks, the intensity of 238U-234U-230Th disequilibria in river sediments will only depend on two parameters: (a) the duration of the transfer including the time spent in soils and in the river, and (b) the nature and the intensity of U-Th fractionations occurring in sediments during their transfer into alluvial plains. Recovering time information from the variation of U-Th disequilibria in such sediments requires therefore the use of realistic models accounting for the U-Th fractionation of sediments during their transfers into the plain. From the data, it is proposed for the Ganges and Bramaputra river sediments, that the main U-Th fractionation process is connected with the sediment weathering during their transit and storage in the plain. In this case the U-Th variation in sediments along the two main rivers lead to quite long sediment transfer time in the alluvial plains, of 100-150 ky for Bramaputra plain and of 400 or 500 ky for the Ganges river. Chabaux F., Riotte J., Dequincey O. (2003) U-Th-Ra fractionation during weathering and river transport, Rev Mineral. Geochem. 52, 533-576. Chabaux, F., Bourdon, B., Riotte, J., 2008. U

  20. The groundwater balance in alluvial plain aquifer at Dehgolan, Kurdistan, Iran

    Science.gov (United States)

    Amini, Ata; Homayounfar, Vafa

    2016-07-01

    In this research, groundwater balance in Dehgolan plain, Kurdistan, Iran was carried out to assess changes in the level and volume of groundwater and water resources management. For this purpose, water resources supplies and consumption data, amount of charging and discharge and water level data recorded from wells and piezometers from 2010 to 2011 water year were gathered and analyzed. Rainfall and water losses of the study area were determined and required maps, including Iso-maps of the temperature, the evaporation, the groundwater level and the aquifer conductivity, were drawn by GIS software. Using the information and drawn maps and the equality of inputs and outputs data, the aquifer water balance was calculated. The results of balance equations showed that the balance is negative indicated a notably decline of groundwater equal to 15.029 million cubic meter (MCM). Such rate of decline is due to the large number of agricultural wells in the region, without considering the hydrological potential of the aquifer.

  1. Characterization of geomorphic units in the alluvial valleys and channels of Gulf Coastal Plain rivers in Texas, with examples from the Brazos, Sabine, and Trinity Rivers, 2010

    Science.gov (United States)

    Coffman, David K.; Malstaff, Greg; Heitmuller, Franklin T.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, described and characterized examples of geomorphic units within the channels and alluvial valleys of Texas Gulf Coastal Plain rivers using a geomorphic unit classification scale that differentiates geomorphic units on the basis of their location either outside or inside the river channel. The geomorphic properties of a river system determine the distribution and type of potential habitat both within and adjacent to the channel. This report characterizes the geomorphic units contained in the river channels and alluvial valleys of Texas Gulf Coastal Plain rivers in the context of the River Styles framework. This report is intended to help Texas Instream Flow Program practitioners, river managers, ecologists and biologists, and others interested in the geomorphology and the physical processes of the rivers of the Texas Gulf Coastal Plain (1) gain insights into how geomorphic units develop and adjust spatially and temporally, and (2) be able to recognize common geomorphic units from the examples cataloged in this report. Recent aerial imagery (high-resolution digital orthoimagery) collected in 2008 and 2009 were inspected by using geographic information system software to identify representative examples of the types of geomorphic units that occurred in the study area. Geomorphic units outside the channels of Texas Gulf Coastal Plain rivers are called \\"valley geomorphic units\\" in this report. Valley geomorphic units for the Texas Gulf Coastal Plain rivers described in this report are terraces, flood plains, crevasses and crevasse splays, flood-plain depressions, tie channels, tributaries, paleochannels, anabranches, distributaries, natural levees, neck cutoffs, oxbow lakes, and constructed channels. Channel geomorphic units occur in the river channel and are subject to frequent stresses associated with flowing water and sediment transport; they adjust (change) relatively quickly in

  2. Soil proifle characteristics of high-productivity alluvial cambisols in the North China Plain

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-tao; LI Bao-guo; REN Tu-sheng

    2015-01-01

    The North China Plain (NCP) is one of major breadbaskets in China. Crop growth and grain yield differ signiifcantly with spatial variations of soil properties. This study aims to identify the key soil properties in relation to the grain yield for the winter wheat (Triticum aestivum L.)-maize (Zea mays L.) cropping system in a high-productivity farmland of the NCP. The ifeld trials were conducted in three ifelds with different grain yield levels in Tai’an City, Shandong Province, China, during the 2009–2012 period. Consistent ifeld management strategies were applied in the three ifelds. Fifty-one physical and chemical indicators of the soil proifle as related to grain yield were evaluated. An approximate maximum of 17.8%annual average grain yield difference was observed in the ifelds during the period of 2009–2012. The soil indicators were classiifed into three clusters with speciifc functions using cluster analysis, and three key indicators were extracted from each cluster to characterize the different soil properties of three ifelds. The ifrst cluster represented soil water retention capacity, and the key indicator was available soil water (ASW), which ranged from 153 to 187 mm in the 1.2 m proifle and was correlated positively with grain yield. The second cluster represented soil water conductivity, as measured by saturated hydraulic conductivity (Ks). The higher yield ifeld had a greater capacity to retain topsoil water for its lower Ks (1.9 cm d–1) in the 30–70 cm soil layer as compared to the lower yield ifeld. The third cluster represented nutrient storage and supply, as indicated by the ratio of nutrient content to silt+clay content of the top soil layer. The ratio of soil organic matter (OM), total nitrogen (TN), available P, exchangeable K+to silt+clay content in the 0–20 cm soil layer were 19.0 g kg–1, 1.6 g kg–1, 94.7 mg kg–1, 174.3 mg kg–1 in the higher yield ifeld, respectively, and correlated positively with the grain yield. By

  3. Macroinvertebrate and diatom metrics as indicators of water-quality conditions in connected depression wetlands in the Mississippi Alluvial Plain

    Science.gov (United States)

    Justus, Billy; Burge, David; Cobb, Jennifer; Marsico, Travis; Bouldin, Jennifer

    2016-01-01

    Methods for assessing wetland conditions must be established so wetlands can be monitored and ecological services can be protected. We evaluated biological indices compiled from macroinvertebrate and diatom metrics developed primarily for streams to assess their ability to indicate water quality in connected depression wetlands. We collected water-quality and biological samples at 24 connected depressions dominated by water tupelo (Nyssa aquatica) or bald cypress (Taxodium distichum) (water depths = 0.5–1.0 m). Water quality of the least-disturbed connected depressions was characteristic of swamps in the southeastern USA, which tend to have low specific conductance, nutrient concentrations, and pH. We compared 162 macroinvertebrate metrics and 123 diatom metrics with a water-quality disturbance gradient. For most metrics, we evaluated richness, % richness, abundance, and % relative abundance values. Three of the 4 macroinvertebrate metrics that were most beneficial for identifying disturbance in connected depressions decreased along the disturbance gradient even though they normally increase relative to stream disturbance. The negative relationship to disturbance of some taxa (e.g., dipterans, mollusks, and crustaceans) that are considered tolerant in streams suggests that the tolerance scale for some macroinvertebrates can differ markedly between streams and wetlands. Three of the 4 metrics chosen for the diatom index reflected published tolerances or fit the usual perception of metric response to disturbance. Both biological indices may be useful in connected depressions elsewhere in the Mississippi Alluvial Plain Ecoregion and could have application in other wetland types. Given the paradoxical relationship of some macroinvertebrate metrics to dissolved O2 (DO), we suggest that the diatom metrics may be easier to interpret and defend for wetlands with low DO concentrations in least-disturbed conditions.

  4. Integration of LiDAR and cropmark remote sensing for the study of fluvial and anthropogenic landforms in the Brenta-Bacchiglione alluvial plain (NE Italy)

    Science.gov (United States)

    Ninfo, Andrea; Mozzi, Paolo; Abbà, Tiziano

    2016-05-01

    The geomorphological study of alluvial plains takes great advantage from the integration of detailed altimetry with high-resolution images, especially in the lower-relief sectors, like those in the distal plain of the Brenta and Bacchiglione rivers near the city of Padua (mean slope 1-0.8‰). The LiDAR data which were specifically acquired for this research (Riegl LMS-Q560, mean density 7 points/m2, overall area 123 km2), were classified and interpolated in order to map fluvial and anthropogenic landforms. The acquisition was carried out in a moment of minimal vegetation luxuriance (March 2011), in order to minimize ground cover. The DEM (z accuracy aggradation, associated with ridges and widespread crevasse channels and splays during the middle Holocene. The derived maps provide significant support to land and urban planning, e.g., in the definition of appropriate geotechnical analysis, the estimation of buried archeological deposits in the city center, and the assessment of flooding hazard.

  5. {sup 210}Pb geochronology and chemical characterization of sediment cores from lakes of the Parana river alluvial plain

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, L.F.L.; Damatto, S.R.; Scapin, M.A. [IPEN - Instituto de Pesquisas Energeticas e Nucleares (Brazil); Remor, M.B.; Sampaio, S.C. [UNIOESTE - Universidade Estadual do Oeste do Parana (Brazil)

    2014-07-01

    The flood plain of the upper Parana River is located among the lakes formed by the Brazilian hydroelectric plants being the last part of the Parana river, in Brazil, where there is an ecosystem with interaction river-flood plain. This flood plain has considerable habitat variability, with great diversity of terrestrial and aquatic species, and the floods are the main factor that regulates the operation of this ecosystem. The seasonality of the flood pulses is mainly influenced by the El Nino phenomenon, which increases precipitation in the drainage basin of the flood plain of the upper Parana River. Because of its unique characteristics this ecosystem is the subject of intense study since 1980, mainly from the ecological point of view. Therefore, two sediment cores were collected in the ponds formed by the floods, Patos pond and Garcas pond, in order to characterize the sediment chemically and evaluate a possible historic contamination. The trace element concentrations As, Ba, Br, Ce, Co, Cr, Cs, Eu, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn (mg.kg{sup -1}) and the major elements Si, Al, Fe, Ti, K, Ca, Mg, P, V, Mn, and Na (%) were determined in the sediment cores dated by {sup 210}Pb method, using instrumental neutron activation analysis, X-ray fluorescence and gross beta counting, respectively. The results obtained for the elements Ce, Cr, Cs, La, Nd, Sc, Sm and Th are higher than the values of Upper Continental Crust for both ponds. The sedimentation rates obtained for Garca pond, 0.77 cm.y{sup -1}, and Patos pond, 0.62 cm.y{sup -1} are in agreement with studies performed in sedimentary environments similar to the present work, such as Brazilian wetland Pantanal. The enrichment factor and the geo-accumulation index were used to assess the presence of anthropogenic sources of pollution. Document available in abstract form only. (authors)

  6. Reconstructing conditions during dolomite formation on a Carnian coastal sabkha/alluvial plain using 87Sr/86Sr isotopes - Travenanzes Formation, northern Italy

    Science.gov (United States)

    Rieder, Maximilian; Wegner, Wencke; Horschinegg, Monika; Preto, Nereo; Breda, Anna; Klötzli, Urs; Peckmann, Jörn; Meister, Patrick

    2016-04-01

    The study of large amounts of dolomite that formed in the Triassic Tethyan realm is hampered by late diagenetic or hydrothermal overprint. These dolomites are difficult to link to past environmental and early diagenetic conditions, and their correlation to models for dolomite formation in modern environments is problematic. Preto et al. (2015) suggested, based on evidence from nano-scale structure analysis by transmission electron microscopy and petrographic observations, that dolomites in the Carnian Travenanzes Formation of the Southern Alps (Dolomites area) represent a preserved primary phase. The Travenanzes Formation was deposited in an extended alluvial plain or coastal sabkha environment subject to a semi-arid climate. Beds and nodules of nearly stoichiometric dolomite are embedded in large amounts of clay, which shielded early formed dolomite from diagenetic fluids. This finding of penecontemporaneous dolomite provides an ideal model case for reconstructing past environmental conditions at the time of dolomite precipitation. While Preto et al. (2015) argued that dolomite formation was mediated by extracellular polymeric substances produced by sulphate-reducing bacteria, it remains unclear whether precipitation occurred from evaporating seawater or mainly from brine derived from evaporating continental groundwater. Both cases exist in modern environments of dolomite formation. In the coastal sabkhas of Abu Dhabi and Qatar, dolomite precipitates from concentrated brine derived from seawater, either through seepage and reflux or through evaporative pumping (the sabkha model). In the coastal ephemeral lakes of the Coorong Lagoon system (South Australia) dolomite precipitation occurs from evaporating groundwater. The goal of this study is to distinguish marine from continental influence during formation of Carnian dolomite using 87Sr/86Sr isotope ratios. Sr isotopes could reveal different origins of ionic solutions for dolomite precipitation, which is not

  7. Impacts of Human Activities on the Occurrence of Groundwater Nitrate in an Alluvial Plain: A Multiple Isotopic Tracers Approach

    Institute of Scientific and Technical Information of China (English)

    Zhonghe Pang; Lijuan Yuan; Tianming Huang; Yanlong Kong; Jilai Liu; Yiman Li

    2013-01-01

    Nitrate pollution is a severe problem in areas with intensive agricultural activities.This study focuses on nitrate occurrence and its constraints in a selected alluvial fan using chemical data combined with environmental isotopic tracers (18O,3H,and 15N).Results show that groundwater nitrate in the study area is as high as 258.0 mg/L (hereafter NO3-) with an average of 86.8 mg/L against national drinking water limit of 45 mg/L and a regional baseline value of 14.4 mg/L.Outside of the riparian zone,nitrate occurrence is closely related to groundwater circulation and application of chemical fertilizer.High groundwater nitrate is found in the recharge area,where nitrate enters into groundwater through vertical infiltration,corresponding to high 3H and enriched 18O in the water.In the riparian zone,on the contrary,the fate of groundwater nitrate is strongly affected by groundwater level.Based on two sampling transects perpendicular to the riverbank,we found that the high level of nitrate corresponds to the deeper water table (25 m) near the urban center,where groundwater is heavily extracted.Groundwater nitrate is much lower (<12.4 mg/L) at localities with a shallow water table (5 m),which is likely caused by denitrification in the aquifer.

  8. Estimation of ground water resources in exploration of water source fields in alluvial plain%冲积平原水源地资源量计算

    Institute of Scientific and Technical Information of China (English)

    冯斌

    2012-01-01

    Estimation of water resources is very important in the exploration of water source field. Base on estimation of the ground water resources of Xiao Li-zhuang water source field in new municipal area of Yongcheng, Henan province, the content and requirement of calculating the groundwater resources for the water source field of the alluvial plain are systematically expounded in this paper. Recharge of ground water includes infiltration of precipitation water and well irrigation. Groundwater excretion includes evaporation, pumping, lateral runoff, and lateral infiltration of surface water.%水源地资源量计算在水源地勘察中非常重要.本文结合河南省永城市新城水厂小李庄水源地的地下水资源量计算实践,系统地阐述了冲积平原水源地地下水资源量计算的内容及要求.其中,地下水补给量包括大气降水入渗补给量和农业井灌回渗补给量.地下水排泄量包括地下水的蒸发量、开采量、侧向径流排泄量和地表水侧渗排泄量.

  9. Assessing hyporheic zone dynamics in two alluvial flood plains of the Southern Alps using water temperature and tracers

    Directory of Open Access Journals (Sweden)

    E. Hoehn

    2006-03-01

    Full Text Available Water temperature can be used as a tracer for the interaction between river water and groundwater, interpreting time shifts in temperature signals as retarded travel times. The water temperature fluctuates on different time scales, the most pronounced of which are the seasonal and diurnal ones. While seasonal fluctuations can be found in any type of shallow groundwater, high-frequency components are more typical for freshly infiltrated river water, or hyporheic groundwater, and are thus better suited for evaluating the travel time of the youngest groundwater component in alluvial aquifer systems. We present temperature time series collected at two sites in the alpine floodplain aquifers of the river Brenno in Southern Switzerland. At the first site, we determine apparent travel times of temperature for both the seasonal and high-frequency components of the temperature signals in several wells. The seasonal signal appears to travel more slowly, indicating a mixture of older and younger groundwater components, which is confirmed by sulphate measurements. The travel times of the high-frequency component qualitatively agree with the groundwater age derived from radon concentrations, which exclusively reflects young water components. Directly after minor floods, the amplitude of temperature fluctuations in an observation well nearby the river is the highest. Within a week, the riverbed is being clogged, leading to stronger attenuation of the temperature fluctuations in the observation well. At the second site, very fast infiltration to depths of 1.9m under the riverbed could be inferred from the time shift of the diurnal temperature signal.

  10. Effects of redox conditions on the control of arsenic mobility in shallow alluvial aquifers on the Venetian Plain (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Carraro, A. [Institute of Geosciences and Earth Resources, National Research Council (CNR) of Italy, Padova, Italy c/o Department of Geosciences, University of Padova, 35131 Padova (Italy); Fabbri, P. [Institute of Geosciences and Earth Resources, National Research Council (CNR) of Italy, Padova, Italy c/o Department of Geosciences, University of Padova, 35131 Padova (Italy); Department of Geosciences, University of Padova, 35131 Padova (Italy); Giaretta, A.; Peruzzo, L.; Tateo, F.; Tellini, F. [Institute of Geosciences and Earth Resources, National Research Council (CNR) of Italy, Padova, Italy c/o Department of Geosciences, University of Padova, 35131 Padova (Italy)

    2015-11-01

    The Venetian Plain is known for the occurrence of areas with high concentrations of arsenic in groundwater (greater than 400 μg/L). The study area represents the typical residential, industrial and agricultural features of most Western countries and is devoid of hydrothermal, volcanic or anthropogenic sources of arsenic. The aim of the study is to model the arsenic mobilization and the water–rock interaction by a complete hydrogeochemical investigation (analyses of filtered and unfiltered groundwater sediment mineralogy and geochemistry). The groundwater arsenic contamination and redox conditions are highly variable. Groundwaters with oxidizing and strongly reducing potentials have much lower arsenic concentrations than do mildly reducing waters. The grain size of the aquifer sediments includes gravels, sands and silty-clays. A continuous range of organic material concentrations is observed (from zero to 40%). The amount of sedimentary organic matter is highly correlated with the arsenic content of the sediments (up to 300 mg/kg), whereas no relationships are detectable between arsenic and other chemical parameters. The occurrence of arsenic minerals was observed as a peculiar feature under the scanning electron microscope. Arsenic and sulfur are the sole constituents of small tufts or thin crystals concentrated in small masses. These arsenic minerals were clearly observed in the peat sediments, in agreement with the geochemical modeling that requires very reducing conditions for their precipitation from the groundwater. The modeling suggests that, under oxidizing conditions, arsenic is adsorbed; moreover, a continuous decrease in the redox potential causes increasing desorption of arsenic. If the reducing conditions become more intense, the formation of As-S minerals would explain the lower concentration of arsenic measured in the strongly reducing groundwater. Even if As-sulfides are rare under low-temperature conditions, the anomalous abundance of reductants

  11. Alluvial Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

  12. Effects of redox conditions on the control of arsenic mobility in shallow alluvial aquifers on the Venetian Plain (Italy).

    Science.gov (United States)

    Carraro, A; Fabbri, P; Giaretta, A; Peruzzo, L; Tateo, F; Tellini, F

    2015-11-01

    The Venetian Plain is known for the occurrence of areas with high concentrations of arsenic in groundwater (greater than 400 μg/L). The study area represents the typical residential, industrial and agricultural features of most Western countries and is devoid of hydrothermal, volcanic or anthropogenic sources of arsenic. The aim of the study is to model the arsenic mobilization and the water-rock interaction by a complete hydrogeochemical investigation (analyses of filtered and unfiltered groundwater sediment mineralogy and geochemistry). The groundwater arsenic contamination and redox conditions are highly variable. Groundwaters with oxidizing and strongly reducing potentials have much lower arsenic concentrations than do mildly reducing waters. The grain size of the aquifer sediments includes gravels, sands and silty-clays. A continuous range of organic material concentrations is observed (from zero to 40%). The amount of sedimentary organic matter is highly correlated with the arsenic content of the sediments (up to 300 mg/kg), whereas no relationships are detectable between arsenic and other chemical parameters. The occurrence of arsenic minerals was observed as a peculiar feature under the scanning electron microscope. Arsenic and sulfur are the sole constituents of small tufts or thin crystals concentrated in small masses. These arsenic minerals were clearly observed in the peat sediments, in agreement with the geochemical modeling that requires very reducing conditions for their precipitation from the groundwater. The modeling suggests that, under oxidizing conditions, arsenic is adsorbed; moreover, a continuous decrease in the redox potential causes increasing desorption of arsenic. If the reducing conditions become more intense, the formation of As-S minerals would explain the lower concentration of arsenic measured in the strongly reducing groundwater. Even if As-sulfides are rare under low-temperature conditions, the anomalous abundance of reductants

  13. 黄河冲积平原灌溉入渗研究%Research on the Irrigation Infiltration in the Yellow River Alluvial Plain

    Institute of Scientific and Technical Information of China (English)

    谭菊萍

    2013-01-01

    黄河冲积平原面积广大,农田灌溉频繁,灌水量大,在地下水资源评价时对灌溉入渗系数取值困难。本文在现场灌溉入渗试验的基础上,分析包气带岩性及结构、水位埋深、灌溉水量对灌溉入渗系数的影响,总结提出了多种条件下灌溉入渗系数的取值范围。在单位灌水量40~60 m3/亩和水位埋深小于4 m、4~8 m、大于8 m的井灌区中,当包气带岩性为粉土、粉砂时,灌溉入渗系数可分别取值0.21~0.10、0.10~0.05、0.05~0;当包气带岩性夹有粉质粘土层时,灌溉入渗系数可分别取值0.15~0.09、0.09~0.05、0.05~0。在单位灌水量较大的渠灌区,灌溉入渗系数可按单位灌水量的增大倍数而增加,由此为黄河冲积平原区地下水补给量计算中灌溉入渗系数的确定提供了依据。%The Yellow River alluvial plain is a large area, whose farmland irrigation is very frequency that wasted a large amount of water. It is hard to obtain irrigation infiltration coefficient values when the groundwater resourc-es are evaluated. In this paper, on the basis of the field irrigation infiltration test, the lithology, structure, water lev-el, and irrigation water in the vadose zone impacting on the irrigation infiltration coefficient was summarized, and the range of irrigation infiltration coefficient on various conditions is proposed. In the well irrigated area, the unit of irrigation water is 240~360 m3 per acre and the groundwater level range is8 m. If there is floury soil and silt in the vadose zone, the value rang of irrigation coefficient infiltration is 0.21~0.10、0.10~0.05、0.05~0, respectively;If it mixed with silty clay layer in the vadose zone, the value rang of irrigation coeffi-cient infiltration is 0.15~0.09、0.09~0.05、0.05~0, respectively. In the canal irrigation district where the unit of irrigation is big, irrigation coefficient infiltration is increased with the multiple

  14. Low frequency amplification in deep alluvial basins: an example in the Po Plain (Northern Italy) and consequences for site specific SHA

    Science.gov (United States)

    Mascandola, Claudia; Massa, Marco; Barani, Simone; Lovati, Sara; Santulin, Marco

    2016-04-01

    This work deals with the problem of long period seismic site amplification that potentially might involve large and deep alluvial basins in case of strong earthquakes. In particular, it is here presented a case study in the Po Plain (Northern Italy), one of the most extended and deep sedimentary basin worldwide. Even if the studied area shows a low annul seismicity rate with rare strong events (Mw>6.0) and it is characterized by low to medium seismic hazard conditions, the seismic risk is significant for the high density of civil and strategic infrastructures (i.e. high degree of exposition) and the unfavourable geological conditions. The aim of this work is to provide general considerations about the seismic site response of the Po Plain, with particular attention on deep discontinuities (i.e. geological bedrock), in terms of potential low frequency amplification and their incidence on the PSHA. The current results were obtained through active and passive geophysical investigations performed near Castelleone, a site where a seismic station, which is part of the INGV (National Institute for Geophysics and Volcanology) Seismic National Network, is installed from 2009. In particular, the active analyses consisted in a MASW and a refraction survey, whereas the passive ones consisted in seismic ambient noise acquisitions with single stations and arrays of increasing aperture. The results in terms of noise HVSR indicate two main peaks, the first around 0.17 Hz and the second, as already stated in the recent literature, around 0.7 Hz. In order to correlate the amplified frequencies with the geological discontinuities, the array acquisitions were processed to obtain a shear waves velocity profile, computed with a joint inversion, considering the experimental dispersion curves and the HVSR results. The obtained velocity profile shows two main discontinuities: the shallower at ~165 m of depth, which can be correlated to the seismic bedrock (i.e. Vs > 800 m/) and the deeper

  15. Spatio-Temporal Variability of Soil Salinity in Alluvial Plain of the Lower Reaches of the Yellow River-A Case Study

    Institute of Scientific and Technical Information of China (English)

    LI Kai-Li; CHEN Jie; TAN Man-Zhi; ZHAO Bing-Zi; MI Shu-Xiao; SHI Xue-Zheng

    2011-01-01

    Soil salinity and hydrologic datasets were assembled to analyze the spatio-temporal variability of salinization in Fengqiu County,Henan Province,China,in the alluvial plain of the lower reaches of the Yellow River.The saline soil and groundwater depth data of the county in 1981 were obtained to serve as a historical reference.Electrical conductivity (EC) of 293 surface soil samples taken from 2 km x 2 km grids in 2007 and 40 soil profiles acquired in 2008 was analyzed and used for comparative mapping.Ordinary kriging was applied to predict EC at unobserved locations to derive the horizontal andvertical distribution patterns and variation of soil salinity.Groundwater table data from 22 observation wells in 2008 were collected and used as input for regression kriging to predict the maximum groundwater depth of the county in 2008.Changes in the groundwater level of Fengqiu County in 27 years from 1981 to 2008 was calculated.Two quantitative criteria,the mean error or bias (ME) and the mean squared error (MSE),were computed to assess the estimation accuracy of the kriging predictions.The results demonstrated that the soil salinity in the upper soil layers decreased dramatically and the taxonomically defined saline soils were present only in a few micro-landscapes after 27 years.Presently,the soils with relatively elevated salt content were mainly distributed in depressions along the Yellow River bed.The reduction in surface soil salinity corresponded to the locations with deepened maximum groundwater depth.It could be concluded that groundwater table recession allowed water to move deeper into the soil profile,transporting salts with it,and thus played an important role in reducing soil salinity in this region.Accumulation of salts in the soil profiles at various depths below the surface indicated that secondary soil salinization would occur when the groundwater was not controlled at a safe depth.

  16. Taphonomy and paleoecology of nonmarine mollusca: indicators of alluvial plain lacustrine sedimentation, upper part of the Tongue River Member, Fort Union Formation ( Paleocene), Northern Powder River Basin, Wyoming and Montana ( USA).

    Science.gov (United States)

    Hanley, J.H.; Flores, R.M.

    1987-01-01

    The composition, species abundances, and spatial and temporal distributions of mollusc assemblages were controlled by the environments in which they lived and the depositional processes that affected the molluscs after death and before final burial. Post-mortem transport, reworking and concentration of shells, and mixing of faunal elements from discrete habitats produced a taphonomic 'overprint' on assemblage characteristics that directly reflects the processes of alluvial plain and floodbasin lacustrine sedimentation. The 'overprint' can be interpreted from outcrop analysis of molluscan biofabric, which consists of: 1) orientation, fragmentation, size-sorting, abrasion, density, and dispersion of shells, 2) the nature and extent of shell-infilling, and 3) ratio of articulated to disarticulated bivalves. Taphonomic characteristics were used with sedimentological properties to differentiate in-place, reworked, transported, and ecologically mixed mollusc assemblages. This study also defines the paleoecology of habitat preferences of mollusc species as a basis for recognition of the environments in which these assemblages were deposited: 1) large floodbasin lakes, 2) small floodbasin lakes, and 3) crevasse deltas and splays. Integration of sedimentology and paleoecology provides an interdisciplinary approach to the interpretation of alluvial environments through time in the Tongue River Member. -Authors

  17. 安徽淮北平原地下水动态变化研究%Study on the Groundwater Dynamic of the Huaibei Alluvial Plain in Anhui Province

    Institute of Scientific and Technical Information of China (English)

    胡巍巍; 王式成; 王根绪; 邓伟

    2009-01-01

    论文对安徽淮北地区69个地下水位站的1980-2006年平均地下水埋深资料进行分析,得出淮北地区多年平均地下水埋深2.33 m,1980-1990年各地下水年均埋深较浅、变幅较小,1990年以后地下水埋深变幅加大,且埋深有明显的加深趋势.研究认为淮北平原地下水动态虽然受降水量、蒸发量和人类活动等多种因素影响,但近些年来地下水的动态变化主要是人类活动影响的结果.这些人类活动包括地下水资源开发利用、土地利用、水利工程、农业节水灌溉措施等.其中过度开发利用地下水是导致安徽淮北平原地下水埋深下降、地下水资源减少的主要原因.适度开发利用地下水有利于淮北地区地下水的循环更新,但过度的开发利用,已造成平原北部开始出现严重的环境地质问题,应限制开采.%Huaibei alluvial plain lies in the middle reach of the Huaihe River basin and the main part of the plain is in Anhui Province. In this region, human activities are intense and water pollution is still serious, so people have to use much groundwater. This article analyzed the annual mean groundwater burying depth from 1980 to 2006 from 69 water table stations on Huaibei alluvial plain, Anhui Province. The authors concluded that multi-annual mean groundwater burying depth is 2.33 m in this region. The annual mean groundwater burying depth was shallow and changed little during the 1980s, but it changed greatly and was apparently deeper after 1990. Although groundwater dynamic is affected by precipitation, evaporation and human activities, the change was the result of human activities in recent years in Huaibei alluvial plain. These activities include groundwater exploitation, land use, hydraulic engineering and agriculture water-saving irrigation measure, and groundwater overexploitation was the main reason for water table decline and groundwater resource decrease. Moderate use of groundwater is

  18. Hydrodynamic characterization of a alluvial flow plain soil of Cajueiro in Tuparetama, Pernambuco State, Brazil - instantaneous profile method; Caracterizacao hidrodinamica de um solo aluvial do acude Cajueiro em Tuparetama, PE - metodo do perfil instantaneo

    Energy Technology Data Exchange (ETDEWEB)

    Robalinho, Aviani Maria B.; Maciel Netto, Andre; Antonino, Antonio Celso Dantas [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear; Audry, Pierre [Institut de Recherche pour le Developpement (IRD), Paris (France)

    2000-07-01

    The knowledge of the hydraulic properties of soil K({theta}) and h({theta}) is required to better management of water transfers in the soils. Determining these properties is highly important in solving problems related to irrigation and drainage, and the transport of nutrients and salts. The experiment was carried out in an alluvial flow plain soil of Cajueiro Dam in Tuparetama, PE. By applying the Instantaneous Profile Method, it was possible to evaluate the hydraulic conductivity of the soil. A parcel of 3.5 m x 3.5 m was delimited for the experiment of internal drainage, and instrumented with an access tube for the neutron probe (water content measurement) and ten tensiometers (measurement of water potential in the soil). The soil profile of Cajueiro Dam is classified as varying from loamy sand (0-80 cm) to sandy (80-100 cm). As to its retention curves h({theta}) and hydraulic conductivity K({theta}), it is classified according to three horizons (0-20 cm), (30-50 cm) and (60-100 cm). In addition, the determination of the hydraulic properties K({theta}) and h({theta}) of the soil gives subsidies for a more efficient handling of this flood plain starting from simulations of soil water transfer processes in the horizons under study. (author)

  19. Contrasting alluvial architecture of Late Pleistocene and Holocene deposits along a 120-km transect from the central Po Plain (northern Italy)

    Science.gov (United States)

    Campo, Bruno; Amorosi, Alessandro; Bruno, Luigi

    2016-07-01

    High-resolution investigation of a ~ 120-km-long transect along the course of the modern Po River, northern Italy, revealed marked changes in alluvial architecture across the Pleistocene-Holocene boundary. Along the whole transect, a 20- to 30-m thick sheet-like succession of Late Pleistocene fluvial sands is invariably overlain by silt and clay deposits, with isolated fluvial bodies of Holocene age (architecture: well-drained floodplain deposits are transitional at distal locations to increasingly organic, poorly drained floodplain to swamp facies associations. Thick paludal facies extend continuously up to 60 km landward of the Holocene maximum marine ingression, about 90 km from the modern shoreline. Based on 28 radiocarbon dates, the abrupt change in lithofacies and channel stacking pattern occurred at the transition from the last glacial period to the present interglacial, under conditions of rapid sea-level rise. The architectural change from amalgamated, Late Pleistocene sand bodies to overlying, mud-dominated Holocene units represent an example of chronologically well-constrained fluvial response to combined climate and relative sea-level change. The overall aggradational stacking pattern of individual channel-belt sand bodies indicates that high subsidence rates continuously created accommodation in the Po Basin, even during phases of falling sea level and lowstand.

  20. Assessing the impacts of sea-level rise and precipitation change on the surficial aquifer in the low-lying coastal alluvial plains and barrier islands, east-central Florida (USA)

    Science.gov (United States)

    Xiao, Han; Wang, Dingbao; Hagen, Scott C.; Medeiros, Stephen C.; Hall, Carlton R.

    2016-11-01

    A three-dimensional variable-density groundwater flow and salinity transport model is implemented using the SEAWAT code to quantify the spatial variation of water-table depth and salinity of the surficial aquifer in Merritt Island and Cape Canaveral Island in east-central Florida (USA) under steady-state 2010 hydrologic and hydrogeologic conditions. The developed model is referred to as the `reference' model and calibrated against field-measured groundwater levels and a map of land use and land cover. Then, five prediction/projection models are developed based on modification of the boundary conditions of the calibrated `reference' model to quantify climate change impacts under various scenarios of sea-level rise and precipitation change projected to 2050. Model results indicate that west Merritt Island will encounter lowland inundation and saltwater intrusion due to its low elevation and flat topography, while climate change impacts on Cape Canaveral Island and east Merritt Island are not significant. The SEAWAT models developed for this study are useful and effective tools for water resources management, land use planning, and climate-change adaptation decision-making in these and other low-lying coastal alluvial plains and barrier island systems.

  1. Assessing the impacts of sea-level rise and precipitation change on the surficial aquifer in the low-lying coastal alluvial plains and barrier islands, east-central Florida (USA)

    Science.gov (United States)

    Xiao, Han; Wang, Dingbao; Hagen, Scott C.; Medeiros, Stephen C.; Hall, Carlton R.

    2016-07-01

    A three-dimensional variable-density groundwater flow and salinity transport model is implemented using the SEAWAT code to quantify the spatial variation of water-table depth and salinity of the surficial aquifer in Merritt Island and Cape Canaveral Island in east-central Florida (USA) under steady-state 2010 hydrologic and hydrogeologic conditions. The developed model is referred to as the `reference' model and calibrated against field-measured groundwater levels and a map of land use and land cover. Then, five prediction/projection models are developed based on modification of the boundary conditions of the calibrated `reference' model to quantify climate change impacts under various scenarios of sea-level rise and precipitation change projected to 2050. Model results indicate that west Merritt Island will encounter lowland inundation and saltwater intrusion due to its low elevation and flat topography, while climate change impacts on Cape Canaveral Island and east Merritt Island are not significant. The SEAWAT models developed for this study are useful and effective tools for water resources management, land use planning, and climate-change adaptation decision-making in these and other low-lying coastal alluvial plains and barrier island systems.

  2. Fertilidade de alguns solos de várzea do vale do Paraíba Fertility of some soils in alluvial plains of the Paraíba valley

    Directory of Open Access Journals (Sweden)

    H. Garcia Blanco

    1964-01-01

    Full Text Available Com a finalidade de avaliar a fertilidade de alguns solos de várzea do vale do rio Paraíba, foram instalados ensaios em vasos com arroz, utilizando as séries Corruçá, Avareí e Brejão. A primeira é argilosa; a segunda, orgânica; a terceira, intermediária das anteriores, isto é, argilo-orgânica. Apesar de os resultados analíticos indicarem teores elevados em nutrientes, as reações às adubações foram intensas na maioria dos casos, induzindo à consideração de que os índices de fertilidade dos solos bem drenados não se aplicam a essas séries. Todos os solos apresentaram reação bastante pronunciada ao nitrogênio. No solo mineral argiloso, não se evidenciou reação ao potássio, mas sòmente a N e P. No argilo-orgânico, o P foi o único elemento que não reagiu. Finalmente, no solo orgânico, reagiram, além do N, os outros dois elementos.A study dealing with the fertility of three soils from alluvial plains in the Paraiba River Valley, State of São Paulo, was carried out in greenhouse tests, with rice (of the Iguape-agulha variety cultivated in pots of 6.0 kg soil capacity. The samples were collected down to 20 cm depth from the following monotype soils series: Corruçá, Brejão and Avareí. The former is an alluvial clay soil and the latter an organic one representing stratified muck and peat; the Brejão series is also organic soil but has an intermediate, organic and clay, texture. The experiment was designed to investigate these soils' needs for the NPK nutrients. In an extra treatment the needs for the minor elements were investigated too. The results obtained in these experiments indicated that the fertility levels based on chemical analyses and applied to fertilization practice to other well drained soils of the State are not satisfactory for the soils in question. A significant favorable response to nitrogen was shown by all the soils studied though they held high content of this element. The response to

  3. Alluvial Deposits in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This coverage maps alluvial deposits throughout Iowa. This generally would include areas of alluvial soils associated with modern streams that are identified on...

  4. Results of geogas test in exploring blind metallic deposits in alluvial plain%冲积平原区隐伏金属矿地气法试验研究

    Institute of Scientific and Technical Information of China (English)

    高玉岩; 汪明启; 夏修展; 王涛

    2011-01-01

    文章通过冲积平原区(山东王家庄铜矿区)的地气试验研究及其与常规土壤测量结果的对比,总结了冲积平原区隐伏金属矿矿床上方地气元素的分布特征.研究结果认为:①在不同覆盖条件、常规土壤测量无效的情况下,地气测量均可发现清晰的金属元素异常,异常强度高,且与矿体空间位置相吻合;显示出地气法在厚覆盖条件下对隐伏金属矿的独特作用;②液体捕集剂和ICP-MS分析方法提高了地气法捕集效率和分析测试数据的可靠性,为地气法的标准化和工程化提供了技术支持,为隐伏金属矿的勘查提供了有效地球化学手段.%Distribution characteristics of geogas elements over metallic deposits concealed by alluvial plain are sumarized on basis of geogas test and research on Wangjiazhuang Cu deposit in Shandong province and comparison between the geogas survey and conventional soil geochemical survey. The results show that: (D the geogas survey displays clear metal element anomalies that are not displayed by conventional soil go-chemical survey under various cover conditions and the geogas anomaly is strong and well coincided spatially with the ore bodies thus geogas survey is unique to discover concealed metallic deposit; (2) the liquid trapping agent and ICP-MS technique improves trapping efficiency and reliability of geogas data and provides technical support of standarization and engineering apllication for the geogas technique and the geogas technique provides a geochemical tool for concealed metallic deposits.

  5. Exploration of the Ecological Costs of Food Production in the Alluvial Region of the Huang-Huai-Hal Plain%黄淮海冲积平原区粮食生产生态成本探究

    Institute of Scientific and Technical Information of China (English)

    李晓; 谢永生; 李文卓; 张应龙

    2011-01-01

    [Objective] Food production are bound to affect the ecological environment. In this paper, the ecological costs of food production were investigated in the alluvial region of the Huang-Huai-Hai Plain. [ Method] Based on the theory of soil erosion and water pollution, using economic and ecological methods to estimate the ecological costs of food production. The grey relationship matrix analysis was used to analyze various factors affecting the ecological costs of food production. [Result] Ecological damage due to grain production in this region was equivalent to 2% of the total agricultural output in 2008. Ecological costs in this region reached 1.51 yuan/kg for wheat and 1.12 yuan/kg for maize in 2008. However, unit sales were 1.62 yuan/kg for wheat and 1.38 yuan/kg for maize. The combination of high production costs and low income affected sustainable development in this region. Yields, acreage, agriculture mechanical costs and labor costs were important factors affecting the ecological costs of food production, chemical fertilizer costs, organic fertilizer costs, pesticides costs and irrigation costs had less impact on the ecological costs of food production. Ecological costs of food production in this region declined as the amount of cultivated land per family increased. [Conclusion] Under current production conditions, moderate improvement of the level of science and technology inputs and expansion of the scale of family agricultural production, then the ecological costs of food production would be reduced. These changes would be conducive to achieving sustainable development of the ecological economy of this region.%[目的]粮食生产必然对生态环境造成影响.以黄淮海冲积平原区河北省曲周县为研究对象,对粮食生产生态成本进行研究.[方法]依据水土流失和水环境污染相关理论,运用生态学和经济学方法对生态成本进行估算;采用灰色关联法对粮食生产生态成本中的

  6. Hidromorfía y condiciones ácuicas en suelos de la llanura aluvial de Tucumán (Argentina Hydromorphy and aquic conditions in soils of the alluvial plain of Tucumán (Argentina

    Directory of Open Access Journals (Sweden)

    Rodolfo Oscar Zappino

    2010-07-01

    Full Text Available Se seleccionaron cuatro perfiles de suelo con distinta clase de drenaje con el objetivo de analizar la intensidad del proceso de hidromorfía, y considerar cuáles cumplen con las condiciones ácuicas. Estos fueron: La Aguadita (Udipsamment típico, térmico, bien drenado, La Fronterita XI (Hapludol típico, franco grueso, illítico, térmico, moderadamente bien drenado, La Fronterita X (Argiudol ácuico, franco fino, illítico, térmico, imperfectamente drenado y Famaillá (Argiu-dol ácuico, fino, illítico, térmico, imperfectamente drenado. Los suelos muestran condiciones de endosaturación durante seis meses al año, con un ascenso del nivel freático durante verano-otoño y un descenso en invierno-primavera. La intensidad de la reducción se evaluó en base a la distribución de hierro y manganeso secundarios asociados a los rasgos redoximórficos identificados micromorfológicamente. En los perfiles bien drenados y moderadamente bien drenados, los Fe d y Mn d mostraron escasa movilidad con valores entre 0,50-0,80% y 0,03-0,06%, respectivamente, y rasgos redoximórficos de escaso desarrollo con un índice Mn/Fe d The profiles of four soils with different drainage types were selected in the alluvial plain of Tucumán in order to analyze the intensity of the hydromorphy and detect which of the soils conforms to an aquic conditions. The four types were: La Aguadita (thermic Typic Udipsamment (well-drained, La Fronterita XI (coarse loamy, illitic, thermic Typic Hapludoll (moderately well-drained, La Fronterita X (fine loamy, illitic, thermic Aquic Argiudoll (imperfectly drained, and Famaillá (fine, illitic, thermic Aquic Argiudoll (imperfectly drained. The soils show endosaturation conditions for six months of the year, with an increase in water level during summer-autumn and a decrease in winter-spring. The degree of reduction was assessed in terms of the distribution of iron and manganese associated with redoximorphic features analyzed on a

  7. Variabilidade espacial de classes de textura, salinidade e condutividade hidráulica de solos em planície aluvial Spatial variability of textural classes, salinity and hydraulic conductivity of soil in an alluvial plain

    Directory of Open Access Journals (Sweden)

    Abelardo A. A. Montenegro

    2006-03-01

    Full Text Available Visando-se avaliar a distribuição de classes texturais e sua correlação espacial com a infiltrabilidade e salinidade de uma área aluvial, no Agreste de Pernambuco, utilizou-se a geoestatística indicadora segundo uma distribuição binária baseada na presença/ausência de solos francos. Considerando-se pontos de amostragem e de testes de infiltração dispostos ao longo do eixo principal do aluvião, e aleatoriamente distribuídos, analisou-se a variabilidade espacial das classes de solo predominantes, da velocidade de infiltração básica (condutividade hidráulica saturada e da condutividade elétrica do extrato de saturação da camada subsuperficial, cujos alcances dos semi-variogramas ajustados foram de 333, 320 e 520 m, respectivamente. Verificou-se que a geoestatística indicadora preservou a correlação espacial entre a textura e a condutividade hidráulica, e entre a textura e a condutividade elétrica. Deste modo, as classes de solo predominantes podem ser usadas para representar distintos padrões no tocante ao potencial de lixiviação e à susceptibilidade de salinização. A metodologia indicadora mostra-se promissora para estudo da variabilidade espacial de propriedades físicas de solos aluviais onde predominam classes contrastantes.Aiming to evaluate the soil textural classes distribution and the spatial correlation between the soil textural classes and both infiltration rate and salinity in an alluvial area, in Pernambuco State "agreste" region, indicator geostatistics has been applied, adopting a binary distribution based on the presence/absence of loam soils. Considering sampling points and test locations along the main longitudinal transect in the valley, as well as randomly distributed locations, the spatial variability of the main soil classes, the infiltration rate, and the electrical conductivity of the saturated extract have been analyzed, for the subsurface soil layer. The fitted semivariogram ranges were 333

  8. Exogenic forces action mechanism in the development process of erosion landform on alluvial plains composed of fluvial-lacustrine deposits in the Taklimakan Desert%塔克拉玛干沙漠河湖相沉积平原风蚀地貌发育的外营力作用机制

    Institute of Scientific and Technical Information of China (English)

    李生宇; 谷峰; 王海峰; 庞营军; 穆桂金; 雷加强; 刘小路; 张忠良; 闫健

    2012-01-01

    河湖相沉积是一种非固结沉积物,是风蚀地貌发育的一种重要地质基础.在塔克拉玛干沙漠中发育在这种沉积物上的风蚀地貌分布非常普遍,但相关研究较少,尚缺乏风蚀地貌发育过程方面的研究.基于野外调查信息和理论分析,结合相关文献,分析了塔克拉玛干沙漠河湖相平原风蚀地貌发育的外营力作用机制.研究结果表明:(1)风蚀地貌发育的外营力作用主要有:风化作用、流水作用、风蚀作用以及重力作用;(2)风蚀作用是风蚀地貌发育的主要外营力,但是风化作用、流水作用和重力作用也发挥着重要的作用,它们的关键作用是形成风蚀突破口,而重力作用和风化作用是促进风蚀地貌后期快速发展的重要作用;(3)各种外营力协同作用和互为条件,它们在风蚀地貌发育的各阶段的重要性不同;(4)沉积层特殊沉积构造和外营力作用共同造成了风蚀地貌形态特征.%Fluvial - lacustrine deposit is a kind of consolidation sediments that is one important geological basis for erosion landform. The erosion landform developed on alluvial plains composed of fluvial - lacustrine deposits is widely distributed. But its relevant studies, especially about the development process of erosion landform are very less. Based on the field survey information, theoretical analysis and some relevant articles, this paper comprehensively analyzed the exogenic forces action mechanism in the development process of erosion landform on alluvial plains composed of fluvial - lacustrine deposits in the Taklimakan Desert. The results show as the following; ( 1) These main exogenic forces including weathering, tunning water, aeolian erosion and gravity drive the erosion land-form development on alluvial plains composed of fluvial - lacustrine deposits in the Taklimakan Desert. (2) Because aeolian activities in the Taklimkan Desert occur very frequent, so aeolian erosion plays a leading

  9. Hydrological connectivity of alluvial Andean valleys: a groundwater/surface-water interaction case study in Ecuador

    Science.gov (United States)

    Guzmán, Pablo; Anibas, Christian; Batelaan, Okke; Huysmans, Marijke; Wyseure, Guido

    2016-06-01

    The Andean region is characterized by important intramontane alluvial and glacial valleys; a typical example is the Tarqui alluvial plain, Ecuador. Such valley plains are densely populated and/or very attractive for urban and infrastructural development. Their aquifers offer opportunities for the required water resources. Groundwater/surface-water (GW-SW) interaction generally entails recharge to or discharge from the aquifer, dependent on the hydraulic connection between surface water and groundwater. Since GW-SW interaction in Andean catchments has hardly been addressed, the objectives of this study are to investigate GW-SW interaction in the Tarqui alluvial plain and to understand the role of the morphology of the alluvial valley in the hydrological response and in the hydrological connection between hillslopes and the aquifers in the valley floor. This study is based on extensive field measurements, groundwater-flow modelling and the application of temperature as a groundwater tracer. Results show that the morphological conditions of a valley influence GW-SW interaction. Gaining and losing river sections are observed in narrow and wide alluvial valley sections, respectively. Modelling shows a strong hydrological connectivity between the hillslopes and the alluvial valley; up to 92 % of recharge of the alluvial deposits originates from lateral flow from the hillslopes. The alluvial plain forms a buffer or transition zone for the river as it sustains a gradual flow from the hills to the river. Future land-use planning and development should include concepts discussed in this study, such as hydrological connectivity, in order to better evaluate impact assessments on water resources and aquatic ecosystems.

  10. Statistic inversion of multi-zone transition probability models for aquifer characterization in alluvial fans

    CERN Document Server

    Zhu, Lin; Gong, Huili; Gable, Carl; Teatini, Pietro

    2015-01-01

    Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This paper develops a statistical inverse framework in a multi-zone transition probability approach for characterizing the heterogeneity in alluvial fans. An analytical solution of the transition probability matrix is used to define the statistical relationships among different hydrofacies and their mean lengths, integral scales, and volumetric proportions. A statistical inversion is conducted to identify the multi-zone transition probability models and estimate the optimal statistical parameters using the modified Gauss-Newton-Levenberg-Marquardt method. The Jacobian matrix is computed by the sensitivity equation method, which results in an accurate inverse solution with quantification of parameter uncertainty. We use the Chaobai River alluvial fan in the Beijing Plain, China, as an example for elucidating the methodology of alluvial fan characterization. The alluvial fan is divided...

  11. Deglacial Flood Origin of the Charleston Alluvial Fan, Lower Mississippi Alluvial Valley

    Science.gov (United States)

    Porter, Donna A.; Guccione, Margaret J.

    1994-05-01

    Large-magnitude flooding of the Mississippi River from proglacial lakes Agassiz and Superior most likely occurred between 11,300 and 10,900 and 9900 and 9500 yr B.P. The Charleston alluvial fan, a depositional remnant of one of these floods, is located at the head of a wide alluvial plain near Charleston, Missouri. The fan is an elongate, convex-up sand body (16 × 24 km) composed of medium- and fine-grained sand at least 8 m thick. This sand contrasts with the older coarse-grained sand of the braided stream surface to the west and south and younger silty clay of the meandering stream level to the north and east. A weakly developed soil separates the underlying braided steam deposits from the alluvial fan. A bulk-soil radiocarbon date of 10,590 ± 200 yr B.P. from the contact between the fan and clays of the meandering stream system indicates that the Charleston fan was deposited near the end of the early interval of flooding from Lake Agassiz about 10,900 yr B.P. If the Charleston fan is the last remnant of deglacial flooding in the lower Mississippi Valley, then deposition of significant quantities of sediment from largemagnitude floods between 10,000 and 9500 yr B.P. did not extend into the lower Mississippi Valley through Thebes Gap.

  12. Analysis and Forecast for Solar Greenhouse Area and Water Saving Amount of Alluvial Plain Region of Haihe Rive in Hebei Province%河北省海河冲击平原区日光温室面积和节水量分析与预测

    Institute of Scientific and Technical Information of China (English)

    张西平; 吴金华; 绳莉丽; 吴现兵; 程伍群

    2012-01-01

    Aiming at the problems as scarcity of water, expansion of facility areas and increasing of water use amount, some indexesof greenhouse of the alluvial plain region of Haihe Rive in Hebei province, as cropping area, cropping pattern, water use efficiency and water saving amount, are analyzed and calculated in Hebei Province. The Gray model (1, 1) is used to predict the area and water saving amount in 2020 and 2030. It is predicted that the areas are 5.48 × 10^4 and 5. 64 × 10^4 hm^2 and the water saving amount are 1.78×10^8 and 1.87×10^8 m^3, respectively.%针对河北省水资源日益紧缺、设施面积逐步扩大及其灌溉用水量的增加等问题,对河北省海河冲击平原区4个分区的日光温室种植面积、种植模式、水分生产效率及灌溉技术节水量进行调查统计和分析计算,采用灰色GM(1,1)预测模型预测了各分区2020年和2030年日光温室的发展面积及灌溉技术节水量。预测发展总面积分别为5.48万hm2和5.64万hm2,节水量分别为17 758.1万m3和18 692.9万m3。

  13. Contamination of the alluvial plain, feeding-stuffs and foodstuffs with polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs) and mercury from the River Elbe in the light of the flood event in August 2002.

    Science.gov (United States)

    Stachel, B; Christoph, E H; Götz, R; Herrmann, T; Krüger, F; Kühn, T; Lay, J; Löffler, J; Päpke, O; Reincke, H; Schröter-Kermani, C; Schwartz, R; Steeg, E; Stehr, D; Uhlig, S; Umlauf, G

    2006-07-01

    Meadow soils, feeding-stuffs and foodstuffs from the alluvial plain of the river Elbe were analyzed in respect of PCDD/Fs, DL-PCBs and mercury with a view to assessing the consequences of the extreme flood of August 2002. The PCDD/F concentrations in the soils range from 3 to 2100 ng WHO-TEQ/kg dm, and for the DL-PCBs the range was 0.32 to 28 ng WHO-TEQ/kg dm. On the basis of established threshold values >40% of the areas are only fit for restricted usage. Mercury concentrations range from 0.11 to 17 mg/kg dm, whereby the action value of 2 mg/kg dm is exceeded in about 50% of the soil samples. A cumulative memory effect from past floods rather than a recent contamination from August 2002 is documented. Soils taken from behind broken dykes showed significantly lower concentrations. Grass, hay and grass silage originating from pasture land in Lower Saxony were taken before and immediately after the flooding. PCDD/Fs range from 0.29 to 16 ng WHO-TEQ/kg, the maximum permitted value of 0.75 ng WHO-TEQ/kg was exceeded in about 50% of the samples. Muscle-tissue from cattle, sheep, lamb and a roe deer as well as untreated milk from individual cows returned values ranging from 0.76 to 5.9 pg WHO-PCDD/F-TEQ/g fat, and 10% of the samples returned values higher than the permitted maximum of 3 pg WHO-PCDD/F-TEQ/g fat. The action value of 2 pg WHO-PCDD/F-TEQ/g fat was exceeded in 33% of the samples. No direct connection between these results and the effects of the flood could be established. A major input path for PCDD/Fs is the tributary Mulde, which discharges contaminated sediments from its catchment area into the Elbe.

  14. Mississippi River Valley alluvial aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Mississippi River Valley alluvial aquifer in the states of Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and...

  15. Utopia Plain

    Science.gov (United States)

    2006-01-01

    5 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark-toned, cratered plain in southwest Utopia Planitia. Large, light-toned, windblown ripples reside on the floors of many of the depressions in the scene, including a long, linear, trough. Location near: 30.3oN, 255.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  16. REVIEW OF REGIME THEORY OF ALLUVIAL CHANNELS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    One of the most important problems in river engineering is to determine a stable cross section geomenry and slope for an alluvial channel. This has been the subject of considerable research for about a century and continues to be of great practical interest. Lgnoring plan geometry, an alluvi-al channel can adjust its slope, depth and width, to develop a dynamic stable condition in which it can transport a certain a-mount of water and sediment. The brief history of regime the-ory and its new development are reviewed in this paper.

  17. Experimental alluvial fans: Advances in understanding of fan dynamics and processes

    Science.gov (United States)

    Clarke, Lucy E.

    2015-09-01

    Alluvial fans are depositional systems that develop because of a disparity between the upstream and downstream sediment transport capacity of a system, usually at the base of mountain fronts as rivers emerge from the constrained mountain area onto the plain. They are dynamic landforms that are prone to abrupt changes on a geomorphological (decades to centuries) time scale, while also being long-term deposition features that preserve sedimentary strata and are sensitive indictors of environmental change. The complexity of interactions between catchment characteristics, climate, tectonics, internal system feedbacks, and environmental processes on field alluvial fans means that it is difficult to isolate individual variables in a field setting; therefore, the controlled conditions afforded by experimental models has provided a novel technique to overcome some of these complexities. The use of experimental models of alluvial fans has a long history and these have been implemented over a range of different research areas utilising various experimental designs. Using this technique, important advances have been made in determining the primary factors influencing fan slope, understanding of avulsion dynamics, identifying autogenic processes driving change on fan systems independent of any change in external conditions, and the mechanics of flow and flood risk on alluvial fans, to name a few. However, experiments cannot be carried out in isolation. Thus, combining the findings from experimental alluvial fans with field research and numerical modelling is important and, likewise, using these techniques to inform experimental design. If this can be achieved, there is potential for future experimental developments to explore key alluvial fan issues such as stratigraphic preservation potential and simulating extra terrestrial fan systems.

  18. Alluvial Boundary of California's Central Valley

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the extent of the alluvial deposits in the Central Valley of California and encompasses the contiguous Sacramento, San Joaquin, and...

  19. Dispersion in alluvial convergent estuaries

    Science.gov (United States)

    Zhang, Zhilin; Savenije, Hubert H. G.

    2016-04-01

    The Van der Burgh's equation for longitudinal effective dispersion is a purely empirical method with practical implications. Its application to the effective tidal average dispersion under equilibrium conditions appears to have excellent performance in a wide range of alluvial estuaries. In this research, we try to find out the physical meaning of Van der Burgh's coefficient. Researchers like MacCready, Fischer, Kuijper, Hansen and Rattray have tried to split up dispersion into its constituents which did not do much to explain overall behaviour. In addition, traditional literature on dispersion is mostly related to flumes with constant cross-section. This research is about understanding the Van der Burgh's coefficient facing the fact that natural estuaries have exponentially varying cross-section. The objective is to derive a simple 1-D model considering both longitudinal and lateral mixing processes based on field observations (theoretical derivation). To that effect, we connect dispersion with salinity using the salt balance equation. Then we calculate the salinity along the longitudinal direction and compare it to the observed salinity. Calibrated dispersion coefficients in a range of estuaries are then compared with new expressions for the Van der Burgh's coefficient K and it is analysed if K varies from estuary to estuary. The set of reliable data used will be from estuaries: Kurau, Perak, Bernam, Selangor, Muar, Endau, Maputo, Thames, Corantijn, Sinnamary, Mae Klong, Lalang, Limpopo, Tha Chin, Chao Phraya, Edisto and Elbe.

  20. Revisiting Plain Language.

    Science.gov (United States)

    Mazur, Beth

    2000-01-01

    Discusses the plain language movement and its origins. Reviews past and current resources related to plain language writing. Examines criticism of the movement while examining past and current plain language literature, with particular attention to the information design field. (SR)

  1. Modeling 3-D permeability distribution in alluvial fans using facies architecture and geophysical acquisitions

    Science.gov (United States)

    Zhu, Lin; Gong, Huili; Dai, Zhenxue; Guo, Gaoxuan; Teatini, Pietro

    2017-02-01

    Alluvial fans are highly heterogeneous in hydraulic properties due to complex depositional processes, which make it difficult to characterize the spatial distribution of the hydraulic conductivity (K). An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional (3-D) setting by using geological and geophysical data. More specifically, a large number of inexpensive vertical electric soundings are integrated with a facies model developed from borehole lithologic data to simulate the log10(K) continuous distributions in multiple-zone heterogeneous alluvial megafans. The Chaobai River alluvial fan in the Beijing Plain, China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multiple-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (zone 1) to the lower (zone 3) portion along the flow direction. In zone 1, sediments were moved by higher-energy flooding, which induces poor sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from zone 1 to zone 3. The results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of K in alluvial fans.

  2. Evolution of Groundwater Major Components in the Hebei Plain:Evidences from 30-Year Monitoring Data

    Institute of Scientific and Technical Information of China (English)

    Yanhong Zhan; Huaming Guo; Yu Wang; Ruimin Li; Chuntang Hou; Jingli Shao; Yali Cui

    2014-01-01

    Groundwater is the main water source in the Hebei Plain. Evolution of groundwater chemistry can not only provide scientific data for sustainable usage of groundwater resources, but also help us in better understanding hydrogeochemical processes in aquifers. Spatial distribution and tem-poral evolution were analyzed on basis of monitoring data between 1975 and 2005. Results showed that major components in groundwater had increasing trends since 1970s. Major components in shallow groundwater increased more than those in deep one. In shallow groundwater of piedmont alluvial fan-recharge zone, concentrations of Na+, Ca2+, SO42- had great increasing trends, while other major components increased by less than 30%. There were great increasing trends in Na+, Cl-, SO42-concen-trations in deep groundwater of central alluvial plain-intermediate zone, while other major components increased by no more than 20%. Deep groundwater from coast plain-discharge zone and piedmont al-luvial fan-recharge zone showed no significant variations in major ion concentrations. In shallow groundwater, dissolution, evaporation and human activities played a major role in the increase in major components. However, groundwater mixture resulting from deep groundwater exploitation was be-lieved to be the major factors for the increases in major components in deep groundwater of central al-luvial plain-intermediate zone.

  3. Alluvial Fan Study Submission for UMATILLA COUNTY, OREGON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Alluvial fan study data as defined in FEMA Guidelines and Specifications, Appendix G: Guidance for Alluvial Fan Flooding Analyses and Mapping

  4. Quaternary alluvial stratigraphy and palaeoclimatic reconstruction at the Thar margin

    DEFF Research Database (Denmark)

    Jain, M.; Tandon, S.K.

    2003-01-01

    Quaternary alluvial record at the Thar desert margin has been examined using the exposed succession along Mahudi, Sabarmati river, Western India. Different alluvial facies, their associations and granulometry have been studied for palaeoenvironmental reconstruction. Clay mineral indices smectite...

  5. Groundwater recharge at five representative sites in the Hebei Plain, China.

    Science.gov (United States)

    Lu, Xiaohui; Jin, Menggui; van Genuchten, Martinus Th; Wang, Bingguo

    2011-01-01

    Accurate estimates of groundwater recharge are essential for effective management of groundwater, especially when supplies are limited such as in many arid and semiarid areas. In the Hebei Plain, China, water shortage is increasingly restricting socioeconomic development, especially for agriculture, which heavily relies on groundwater. Human activities have greatly changed groundwater recharge there during the past several decades. To obtain better estimates of recharge in the plain, five representative sites were selected to investigate the effects of irrigation and water table depth on groundwater recharge. At each site, a one-dimensional unsaturated flow model (Hydrus-1D) was calibrated using field data of climate, soil moisture, and groundwater levels. A sensitivity analysis of evapotranspirative fluxes and various soil hydraulic parameters confirmed that fine-textured surface soils generally generate less recharge. Model calculations showed that recharge on average is about 175 mm/year in the piedmont plain to the west, and 133 mm/year in both the central alluvial and lacustrine plains and the coastal plain to the east. Temporal and spatial variations in the recharge processes were significant in response to rainfall and irrigation. Peak time-lags between infiltration (rainfall plus irrigation) and recharge were 18 to 35 days in the piedmont plain and 3 to 5 days in the central alluvial and lacustrine plains, but only 1 or 2 days in the coastal plain. This implies that different time-lags corresponding to different water table depths must be considered when estimating or modeling groundwater recharge.

  6. Characterization of land subsidence induced by groundwater withdrawals in Wenyu River alluvial fan, Beijing, China

    Science.gov (United States)

    Wang, R.; Luo, Y.; Yang, Y.; Tian, F.; Zhou, Y.; Tian, M.-Z.

    2015-11-01

    The Beijing plain area has suffered from severe land subsidence owing to groundwater overdraft. A major example is the Wenyu River alluvial fan in the Beijing plain area. This area has experienced as much as 10 m of land subsidence through 2000s. An integrated subsidence-monitoring program, including borehole extensometer and multilayer monitoring of groundwater, has been designed to meet the needs of monitoring land subsidence in this region. This work has allowed us to characterize land subsidence and understand the mechanical properties of the strata. The analysis results show the development of the land subsidence in this area is consistent with water-level change. The major strata contributing to compression deformation are Mid-Pleistocene stratum which contributed around 70 % of total subsidence. The shallow stratum and deep stratum show elastic mechanical behavior the intermediate stratum exhibit elastic-plastic mechanical behavior.

  7. Geomorphology, internal structure and evolution of alluvial fans at Motozintla, Chiapas, Mexico

    Science.gov (United States)

    Sánchez-Núñez, J. M.; Macías, J. L.; Saucedo, Ricardo; Zamorano, J. J.; Novelo, David; Mendoza, M. E.; Torres-Hernández, J. R.

    2015-02-01

    Alluvial fans and terraces develop in diverse regions responding to different tectonic and climatic conditions. The Motozintla basin is located in the State of Chiapas, southern Mexico and has an E-W orientation following the trace of the left-lateral Polochic Fault. The evolution of the Motozintla basin and the alluvial plain is related to several factors, such as fault movement, intense erosion by hydrometeorological events, and anthropogenic activity. This study presents the geomorphology of the alluvial plain that between the villages of Motozintla and Mazapa de Juárez exposes 31 alluvial fans, 5 hanging terraces and 13 ramps. Fourteen of these alluvial fans have been truncated by the Polochic fault, exposing maximum uplifts of ~ 12 m. The internal structure of truncated fans consists of single massive beds (monolithologic fans) or stacked beds (polygenetic fans). The fans' stratigraphy is made of debris flow deposits separated by paleosols and minor hyperconcentrated flows, fluviatile beds, and pyroclastic fall deposits. The reconstruction of the stratigraphy assisted by radiocarbon geochronology suggests that these fans have been active since late Pleistocene (25 ka) to the present. This record suggests that at least 10 events have been recorded at the fan interior during the past ~ 1840 years. One of these events at 355 ± 65 14C yrs. BP (cal yrs. AD 1438 to 1652) can be correlated across the fans and is likely associated with an extreme hydrometeorologic event. The presence of a 165 ± 60 14C yrs. BP (cal yrs. AD 1652-1949) debris flow deposit within the fans suggests that movement along the Polochic fault formed the fans' scarp afterwards. In fact, a historic earthquake along the fault occurred east of Motozintla on July 22, 1816 with a Mw of 7.5-7.75. Recent catastrophic floods have affected Motozintla in 1998 and 2005 induced by extreme hydrometeorological events and anthropogenic factors. Therefore, scenarios for Motozintla involved several types of

  8. Composition and provenance of Late Pleistocene-Holocene alluvial sediments of the eastern Andean piedmont between 33 and 34° S (Mendoza Province, Argentina)

    Science.gov (United States)

    Mehl, A.; Blasi, A.; Zárate, M.

    2012-12-01

    The Andean cordillera, and its piedmont in the central western Argentina, has been long considered as one of the main source areas of detritus for the Chaco-Pampean plain sand dune fields and loess/loess-like deposits of central Argentina. The main goal of this study is to evaluate the composition of the late Pleistocene-Holocene alluvial deposits of the Andes cordillera piedmont, from 33° to 34° S. The results are interpreted in the context of the regional geology, tectonic setting of the study area and its implications in the continent-wide perspective of modern alluvial sands proposed by Potter (1994). Sampling was conducted at the alluvial stratigraphic sequences of four study sites along three Andean piedmont arroyos; modal mineralogy in the very fine sand fraction (3 phi to 4 phi) was determined using standard petrographic microscope methods. Q:F:LF average compositions indicate that the Late Pleistocene-Holocene very fine-grained alluvial sands of the Cordillera Frontal piedmont reflects the modern lithic arenites of the Argentine Association reported by Potter (1994). The results show two geologically distinct sources in the catchment areas, volcaniclastic and metamorphic rocks. High concentrations of mica and volcanic glass are likely related to particle morphologies and to the deposition sedimentary environment recorded in the alluvial sequences—floodplains. The overabundance of micas over the volcanic glass in the mid-late Holocene alluvial sequence indicates the drainage of a metamorphic area at the expense of other lithological sources. Source areas are located mainly in the Frontal cordillera, and to a lesser extent, in the piedmont Tertiary deposits, another likely source for the analyzed Quaternary alluvial sediments. The mineralogical signature of the late Pleistocene and Holocene alluvial sequences is in agreement with the composition of the southern Pampean sand mantles, loess and loess-like deposits mainly formed by a volcanic mineral

  9. Generalized sorting profile of alluvial fans

    Science.gov (United States)

    Miller, Kimberly Litwin; Reitz, Meredith D.; Jerolmack, Douglas J.

    2014-10-01

    Alluvial rivers often exhibit self-similar gravel size distributions and abrupt gravel-sand transitions. Experiments suggest that these sorting patterns are established rapidly, but how—and how fast—this convergence occurs in the field is unknown. We examine the establishment of downstream sorting patterns in a kilometer-scale alluvial fan. The sharp transition from canyon to unconfined, channelized fan provides a well-defined boundary condition. The channel changes from deep and entrenched at the fan apex to shallow and depositional over a short distance, exhibiting nonequilibrium behavior. The resulting gravel-fining profile is not self-similar; the particle size distribution narrows until approximate equal mobility is achieved. Downfan, the gravel-sand transition appears to exhibit a self-similar form; field and laboratory data collapse when downstream distance is normalized by the location of the transition. Results suggest a generalized sorting profile for alluvial fans as a consequence of the threshold of motion and nonequilibrium channels.

  10. Geohazards (floods and landslides in the Ndop plain, Cameroon volcanic line

    Directory of Open Access Journals (Sweden)

    Wotchoko Pierre

    2016-07-01

    Full Text Available The Ndop Plain, located along the Cameroon Volcanic Line (CVL, is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually and landslides (occasionally occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered.

  11. CHANNEL WIDENING DURING DEGRADATION OF ALLUVIAL RIVERS

    Institute of Scientific and Technical Information of China (English)

    Guangqian WANG; Junqiang XIA

    2001-01-01

    This paper first describes the phenomenon of channel widening during degradation of alluvial rivers,explains the mechanisms of channel widening, and analyzes the stability of cohesive riverbank. Then a one-dimensional mathematical model is developed to simulate the transport of non-uniform suspended sediments, with a sub-model for the simulation of channel widening, and is used to study the process of channel widening during degradation. The effects of different incident flow and sediment conditions and different riverbank material characteristics on channel widening and bed degradation are compared.Finally, main factors that control the deformation processes are identified.

  12. Buried paleoindian-age landscapes in stream valleys of the central plains, USA

    Science.gov (United States)

    Mandel, R.D.

    2008-01-01

    A systematic study of late-Quaternary landscape evolution in the Central Plains documented widespread, deeply buried paleosols that represent Paleoindian-age landscapes in terrace fills of large streams (> 5th order), in alluvial fans, and in draws in areas of western Kansas with a thick loess mantle. Alluvial stratigraphic sections were investigated along a steep bio-climatic gradient extending from the moist-subhumid forest-prairie border of the east-central Plains to the dry-subhumid and semi-arid shortgrass prairie of the west-central Plains. Radiocarbon ages indicate that most large streams were characterized by slow aggradation accompanied by cumulic soil development from ca. 11,500 to 10,000??14C yr B.P. In the valleys of some large streams, such as the Ninnescah and Saline rivers, these processes continued into the early Holocene. The soil-stratigraphic record in the draws of western Kansas indicates slow aggradation punctuated by episodes of landscape stability and pedogenesis beginning as early as ca. 13,300??14C yr B.P. and spanning the Pleistocene-Holocene boundary. The development record of alluvial fans in western Kansas is similar to the record in the draws; slow aggradation was punctuated by multiple episodes of soil development between ca. 13,000 and 9000??14C yr B.P. In eastern Kansas and Nebraska, development of alluvial fans was common during the early and middle Holocene, but evidence shows fan development as early as ca. 11,300??14C yr B.P. Buried soils dating between ca. 12,600 and 9000??14C yr B.P. were documented in fans throughout the region. In stream valleys across the Central Plains, rapid alluviation after ca. 9000??14C yr B.P. resulted in deeply buried soils that may harbor Paleoindian cultural deposits. Hence, the paucity of recorded stratified Paleoindian sites in the Central Plains is probably related to poor visibility (i.e., deep burial in alluvial deposits) instead of limited human occupation in the region during the terminal

  13. The current status, threats and protection way of Sanjiang Plain wetland, Northeast China

    Institute of Scientific and Technical Information of China (English)

    ZHOUZhi-qiang; LIUTong

    2005-01-01

    The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exist on the Sanjiang Plain, and three of them have been listed as wetlands of international importance to water bird conservation by the Ramsar Convention Bureau. The wetlands of Sanjiang Plain are noteworthy for its rich biodiversity, but they continue to decline in area and deteriorate in quality currently. The main threats or constrains, immediate cause, root cause and required response are analyzed in this paper, and the four aspects opinion such as improvement of watershed management, enhancement of protection and restoration of habitats and biodiversity, alternative livelihoods of rural residents living in and near natural wetland reserve, and reinforcement of capacity building of natural reserves are brought forward as the effective measures for the Sanjiang Plain wetland protection.

  14. Analysis of developing non-timber forest products of Sanjiang Plain,Northeast China

    Institute of Scientific and Technical Information of China (English)

    LIU Tong; ZHOU Zhi-qiang

    2006-01-01

    The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.

  15. Geomorphological development of Eastern Mongolian plain, Mongolia

    Science.gov (United States)

    khukhuudei, Ulambadrakh; otgonbayar, Orolzodmaa

    2016-04-01

    Several summaries and investigations of the geomorphological description and feature for Eastern Mongolian plain (EMP), the one of the largest geomorphological district, fully covering east side of Mongolia (Murzayev, 1949; Vlodavets, 1950, 1955; Marinov, Khasin, 1954; Marinov, 1966; Nikolayeva, 1971; Selivanov, 1972; Chichagov, 1974, 1976; Grigorov, 1975; Korjuyev, 1982; Syirnev, 1982, 1984) had been publishing continuously. But literature for geomorphology of EMP have been not appeared during over the past 20 years. However, we re-combine the geomorphological development of EMP, according to the results of many publications for surrounding regions of Russia and China and unpublished maps. Main morphology of EMP has the plain, containing with aeolian, fluvial and lacustrine landforms. Plain morphology defined that denudation plains to North Kherlen, South Kherlen, Baruun Urt, Uulbayan, Delgerekh and other which developed on the Paleozoic rocks, layered plain to Choibalsan, Tamsag, Ongon, Gert, Sumiin nuur and Torey- on the Late Cretaceous and Neogene sediments and accumulation plain with alluvial and lacustrine origin such as Menen, Buir nuur, Tamsagbulag, Khalzan and other. These plains of EMP related with tectonics and structure of region and inherited the development of the Mesozoic, particularly Late Mesozoic structure. Large basins of EMP are Tamsag, Choibalsan and Torey and other small basins - from 7-10 km to 25-30 km width and rather a several 10 km extend, cutting a basement. The origin of plain morphology for EMP is interpreted as two main stages of the geomorphological development model, based on geology. In first stage or Late Jurassic (?) - Lower Cretaceous period, there was developed rift basin, then, in second stage or since Late Cretaceous period, plain morphology originated from the intermountain basin that dominated by exogenic process and kept in current EMP area. Data relevant to the development history of EMP are following. 1. Rift volcanism

  16. Response of Groundwater to Climate Change under Extreme Climate Conditions in North China Plain

    Institute of Scientific and Technical Information of China (English)

    Ying Zhang; Jincui Wang; Jihong Jing; Jichao Sun

    2014-01-01

    The North China Plain (NCP) is one of the water shortage areas of China. Lack of water resources restricted the economic and social development of North China area and resulted in deterio-ration of ecosystem and natural environment. Influenced by the climate change and human activities, the water circulation of NCP was largely changed and the crisis of water resources was aggravated. Therefore, it is important to study the features of the extreme climate and the response mechanism of groundwater to climate change. We analyzed the trend of climate change and extreme climate features in the past 60 years based on the monitoring data of meteorological stations. And then the response characteristics of groundwater to climate change were discussed. The average temperature of NCP was in an obviously upward trend. The overall precipitation variation was in a downward trend. The cli-mate change in this area showed a warming-drying trend. The intensity of extreme precipitation dis-played a trend of declining and then increasing from north to south as well as declining from eastern coastal plain to the piedmont plain. Grey correlation degree analysis indicated that groundwater depth had a close relationship with precipitation and human activities in NCP. The response of groundwater level to precipitation differed from the piedmont alluvial-pluvial plain to the coastal plain. The response was more obvious in the coastal plain than the piedmont alluvial-pluvial plain and the middle plain. The precipitation influenced the groundwater depth both directly and indirectly. Under the condition of extreme precipitation, the impact would aggravate, in the forms of rapid or lag raise of groundwater levels.

  17. The Plains of Venus

    Science.gov (United States)

    Sharpton, V. L.

    2013-12-01

    Volcanic plains units of various types comprise at least 80% of the surface of Venus. Though devoid of topographic splendor and, therefore often overlooked, these plains units house a spectacular array of volcanic, tectonic, and impact features. Here I propose that the plains hold the keys to understanding the resurfacing history of Venus and resolving the global stratigraphy debate. The quasi-random distribution of impact craters and the small number that have been conspicuously modified from the outside by plains-forming volcanism have led some to propose that Venus was catastrophically resurfaced around 725×375 Ma with little volcanism since. Challenges, however, hinge on interpretations of certain morphological characteristics of impact craters: For instance, Venusian impact craters exhibit either radar dark (smooth) floor deposits or bright, blocky floors. Bright floor craters (BFC) are typically 100-400 m deeper than dark floor craters (DFC). Furthermore, all 58 impact craters with ephemeral bright ejecta rays and/or distal parabolic ejecta patterns have bright floor deposits. This suggests that BFCs are younger, on average, than DFCs. These observations suggest that DFCs could be partially filled with lava during plains emplacement and, therefore, are not strictly younger than the plains units as widely held. Because the DFC group comprises ~80% of the total crater population on Venus the recalculated emplacement age of the plains would be ~145 Ma if DFCs are indeed volcanically modified during plains formation. Improved image and topographic data are required to measure stratigraphic and morphometric relationships and resolve this issue. Plains units are also home to an abundant and diverse set of volcanic features including steep-sided domes, shield fields, isolated volcanoes, collapse features and lava channels, some of which extend for 1000s of kilometers. The inferred viscosity range of plains-forming lavas, therefore, is immense, ranging from the

  18. On the Role of Flash Floods for Dust Emission over North Africa: Alluvial Sediments acting as Dust Source

    Science.gov (United States)

    Schepanski, K.; Klueser, L.; Tegen, I.

    2014-12-01

    Studies analyzing satellite dust products show that numerous dust sources are located in the foothills of arid and semi-arid mountain regions. There, alluvial sediments deposited on valley bottoms and flood plains are very susceptible to wind erosion and frequently serve as dust source. This study focuses on the spatio-temporal distribution of dust source activation events over the mountain foothills and flood plains over North Africa. Satellite dust retrievals with sub-daily resolution such as from Meteosat Second Generation (MSG) Spinning Enhanced Visible and InfraRed Imager (SEVIRI) and METOP A/B Infrared Atmospheric Sounding Interferometer (IASI) instruments are used to identify dust source regions. Identified dust source regions are then linked to soil properties and land type classification data sets. Information on the mineralogical composition of transported dust inferred from IASI observation are used (a) to investigate the impact of different source geomorphologies and thus different radiative properties of airborne dust particles, and (b) to estimate the contribution of dust uplift from alluvial sediments compared to dust emission from non-hydrological sources. Ultimately, this study contributes to the understanding of controlling mechanism on the interannual variability of dust source activation and will improve current dust emission modules coupled to atmosphere models.

  19. Effects of Alluvial and Debris Flow Fans on Channel Morphology in Idaho, Washington, and Oregon

    Science.gov (United States)

    Bigelow, P. E.; Benda, L.; Miller, D.; Andras, K.

    2003-12-01

    Formation of debris flow and alluvial fans at tributary confluences from episodic erosion associated with large storms and fires ("extreme events") are often viewed negatively over short time spans (years). However, when viewed over long periods of time (decades to centuries), fans that form at tributary junctions are often sources of morphological diversity in streams and rivers. To evaluate effects of tributary fans on the morphology of mainstem channels, we surveyed a total of 44 km of streams in the Sawtooth Mountains of Idaho (27 km), Olympic Mountains of Washington (10 km), and Central Coast Range of Oregon (7 km). Rejuvenated alluvial fans resulting from post-fire gully erosion in the Sawtooth Mountains created gradient nick points in 4th to 6th order mainstem channels (30 to 350 km2 drainage area) that increased sediment storage upstream resulting in decreased channel gradients, widened flood plains, side channel construction, and the beginning of terrace formation. Downstream effects included increased channel gradients, often creating rapids. In 3rd and 4th order mainstem channels (< 10 km2 drainage area) in the Olympic Mountains, there was statistically significant association between low-order confluences containing debris flow deposits and gravel abundance, wide channels, and numbers of logs and large pools. Moreover, heterogeneity of mainstem channel morphology increased in proximity to low-order confluences prone to debris flows in the Olympic study sites. In 3rd and 4th order channels in the Oregon Coast Range, density of large wood and boulders in mainstem channels (< 30 km2 drainage area) increased with proximity to all debris flow fans at low-order confluences regardless of fan age, while channel gradients and sediment depth in mainstem channels increased with proximity to recent (< 60 yrs old) debris fans. Consequently, alluvial and debris flow fans can be significant agents of heterogeneity in riverine habitats, similar to other sources of

  20. Alluvial basin statistics of the Southwest Principal Aquifers (SWPA) study.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — SWPA_alvbsn is a vector dataset of alluvial-fill basin statistics for the Southwest United States. Statistics for each basin include physical details such as area,...

  1. Aquifers of Alluvial and Glacial Origin - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the alluvial and glacial aquifers north of the southern-most line of glaciation. Aquifers are shown in the States of Maine,...

  2. Effects of alluvial knickpoint migration on floodplain ecology and geomorphology

    Science.gov (United States)

    Larsen, Annegret; May, Jan-Hendrick

    2016-04-01

    Alluvial knickpoints are well described as erosional mechanism within discontinuous ephemeral streams in the semi-arid SW USA. However, alluvial knickpoints occur globally in a wide range of settings and of climate zones, including temperate SE Australia, subtropical Africa, and tropical Australia. Much attention has been given in the scientific literature to the trigger mechanisms of alluvial knickpoints, which can be summarized as: i) threshold phenomena, ii) climate variability and iii) land-use change, or to a combination of these factors. Recently, studies have focused on the timescale of alluvial knickpoint retreat, and the processes, mechanisms and feedbacks with ecology, geomorphology and hydrology. In this study, we compile data from a global literature review with a case study on a tropical river system in Australia affected by re-occurring, fast migrating (140 myr-1) alluvial knickpoint. We highlight the importance of potential water table declines due to channel incision following knickpoint migration, which in turn leads to the destabilization of river banks, and a shift in floodplain vegetation and fire incursion. We hypothesize that the observed feedbacks might also help to understand the broader impacts of alluvial knickpoint migration in other regions, and might explain the drastic effects of knickpoint migration on land cover and land-use in semi-arid areas.

  3. The provenance of Borneo's enigmatic alluvial diamonds

    Science.gov (United States)

    White, Lloyd; Graham, Ian; Tanner, Dominique; Hall, Robert; Armstrong, Richard; Yaxley, Greg; Barron, Larry; Spencer, Lee; van Leeuwen, Theo

    2016-04-01

    Gem-quality diamonds occur in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Numerous geological models have been proposed to explain the distribution of Borneo's diamonds. To assess these models, we used a variety of techniques to examine heavy minerals from Kalimantan's Cempaka paleoalluvial diamond deposit. This involved collecting U-Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. Our results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal recording several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The 'local' diamonds could be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains, or could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin. If this were the case, these intrusions would indicate that the lithosphere beneath SW Borneo is thick (~150 km or greater).

  4. Geomorphology and flood-plain vegetation of the Sprague and lower Sycan Rivers, Klamath Basin, Oregon

    Science.gov (United States)

    O'Connor, James E.; McDowell, Patricia F.; Lind, Pollyanna; Rasmussen, Christine G.; Keith, Mackenzie K.

    2015-01-01

    This study provides information on channel and flood-plain processes and historical trends to guide effective restoration and monitoring strategies for the Sprague River Basin, a primary tributary (via the lower Williamson River) of Upper Klamath Lake, Oregon. The study area covered the lower, alluvial segments of the Sprague River system, including the lower parts of the Sycan River, North Fork Sprague River, South Fork Sprague River, and the entire main-stem Sprague River between the confluence of the North Fork Sprague and the South Fork Sprague Rivers and its confluence with the Williamson River at Chiloquin, Oregon. The study included mapping and stratigraphic analysis of flood-plain deposits and flanking features; evaluation of historical records, maps and photographs; mapping and analysis of flood-plain and channel characteristics (including morphologic and vegetation conditions); and a 2006 survey of depositional features left by high flows during the winter and spring of 2005–06.

  5. Late Quaternary geology of the Lower Central Plain, Thailand

    Science.gov (United States)

    Sinsakul, Sin

    2000-08-01

    The Lower Central Plain or Chao Phraya Plain, located in the upper Gulf of Thailand, has an average elevation of 2 m above the present mean sea level. It is a fault bounded basin developed in the Plio-Pleistocene epoch. Consequently, the basin has been filled with Quaternary sediment reaching a thickness of almost 2000 m, of which only the upper 300 m is known. The Pleistocene deposits of the Lower Central Plain represent a complex interplay of alluvial, fluvial and deltaic environments of the Chao Phraya River and its tributaries. The upper sequence of sand and stiff clay with iron-oxide concretions on the surface was deposited in a fluviatile environment subjected to a regressive period in the late Pleistocene. The term "Chao Phraya delta" is used to define the landform where the Chao Phraya River interacted with marine processes as the sea level changed during the Holocene transgression. These strata indicated that the Holocene sea reached its maximum height of 4 m above the present mean sea level around 6000 years B.P.; from then on sea level fluctuated until it reached its present level around 1500 years B.P. This complex sea level history has caused the progradation of tidal flat, and tide-dominated delta deposits, consisting of soft marine clay, that covered the Lower Central Plain to an average depth of 15 m in the Bangkok area. The soft marine clay or Bangkok clay is the most important unit in the stratigraphic sequence in terms of land subsidence in the Lower Central Plain. Evidence of coastal erosion is also considerable in the low tidal flat area on the west bank of the Chao Phraya River mouth and adjacent coast.

  6. Recovery capacitv of groundwater system in lower Liaohe River Plain%下辽河平原地下水系统恢复力研究

    Institute of Scientific and Technical Information of China (English)

    孙才志; 胡冬玲; 杨磊

    2011-01-01

    在科学把握地下水系统恢复力概念和内涵的基础上,从地下水含水层特性、补给条件、区域特点、技术水平和社会经济5个方面选取26个典型指标构建了下辽河平原地下水系统恢复力指标体系,并对指标的评价标准进行划分,采用层次分析法和GIS空间叠加技术对其地下水系统恢复力进行评价,结果表明:新民-辽中平原、柳河平原和南部滨海平原地下水系统恢复力较强;辽河冲积扇、浑河冲积扇、太子河冲积扇及西部扇前平原的部分地区恢复力处于中等水平;大小凌河冲积扇、羊肠河冲积扇、黑鱼沟河冲积扇、海城河冲积扇和北部的阜新、铁岭等地恢复力最弱,有待进一步提高.%Based on the scientific understanding of the concept and meaning of the recovery capacity of groundwater system, an evaluation system for the lower Iiaohe River Plain was established by selecting twenty-six typical indexes from five aspects of characteristics of groundwater aquifer, supply conditions, regional characteristics, technical level and social economy. The evaluation standards for the indexes were classified into different categories. The analytic hierarchy process and the GIS space stacking technique were employed to evaluate the recovery capacity of groundwater system. The results show that the recovery capacity of Xinmin-liaozhong plain, Liuhe plain and the southern coastal plain is the strongest, that of Iiaohe alluvial fan, Hunhe alluvial fan, Taizihe alluvial fan and the western plain is intermediate, and that of Iinghe alluvial fans, Yangchang River alluvial fan, Heiyugou River alluvial fan, Haicheng River alluvial fan and Fuxin and Tieling in the northern area is the weakest and needs to be further improved. The research achievements are significant for the sustainable exploitation of water resources in the lower Iiaohe River Plain.

  7. Characterizing subsurface hydraulic heterogeneity of alluvial fan using riverstage fluctuations

    Science.gov (United States)

    Wang, Yu-Li; Yeh, Tian-Chyi Jim; Wen, Jet-Chau; Huang, Shao-Yang; Zha, Yuanyuan; Tsai, Jui-Pin; Hao, Yonghong; Liang, Yue

    2017-04-01

    The objective of this study is to demonstrate the ability of riverstage tomography to estimate 2-D spatial distribution of hydraulic diffusivity (D) of Zhuoshui River alluvial fan, Taiwan, using groundwater level data from 65 wells and stream stage data from 5 gauging stations. In order to accomplish this objective, wavelet analysis is first conducted to investigate the temporal characteristics of groundwater level, precipitation, and stream stage. The results of the analysis show that variations of groundwater level and stream stage are highly correlated over seasonal and annual periods while that between precipitation is less significant. Subsequently, spatial cross-correlation between seasonal variations of groundwater level and riverstage data is analyzed. It is found that the correlation contour map reflects the pattern of sediment distribution of the fan. This finding is further substantiated by the cross-correlation analysis using both noisy and noise-free groundwater and riverstage data of a synthetic aquifer, where aquifer heterogeneity is known exactly. The ability of riverstage tomography is then tested with these synthetic data sets to estimate D distribution. Finally, the riverstage tomography is applied to the alluvial fan. The results of the application reveal that the apex and southeast of the alluvial fan are regions with relatively high D and the D values gradually decrease toward the shoreline of the fan. In addition, D at northern alluvial fan is slightly larger than that at southern. These findings are consistent with the geologic evolution of this alluvial fan.

  8. Development and lithogenesis of the palustrine and calcrete deposits of the Dibdibba Alluvial Fan, Kuwait

    Science.gov (United States)

    AlShuaibi, Arafat A.; Khalaf, Fikry I.

    2011-08-01

    A model is proposed for the development of the Quaternary palustrine carbonate-calcrete association, which occurs as hard crust capping low hills at a distal flood plain of Al Dibdibba alluvial fan located at southwestern Kuwait. Field occurrence, detailed petrographic investigation and geochemical analysis revealed that a single cycle of groundwater calcrete with vertical gradational maturity pattern was developed. This represents a continuous sedimentological cycle during which flood sheet conditions prevailed with intermittent periods of humid and arid conditions. Subsequently, calcitic micrite was continuously precipitated from small, shallow, local, isolated and short lived ponds fringed by freshwater marshes with abundant charophyte meadows. The latter were developed as a result of flooding scattered depressions by groundwater supersaturated with respect to calcite due to rise of groundwater table. The deposition of two facies of carbonate muds, namely; biomicrite and pelintraclasts skeletal micrites was followed by a drought phase which witnessed desiccation of the fresh water ponds and significant drop in groundwater level. A sequence of pedogenic and diagenetic processes acted on the deposited carbonate muds are manifested by: (a) desiccation cracks, (b) micrite neomorphism, (c) infilling of root burrows and some cracks by aeolian siliciclastics, (d) karstification, (e) marmorization, (f) calcretization of root burrow infill and development of pseudo-rhizocrete, (g) calcite cementation and mineral authigenesis, and (h) silcretization. These processes are responsible for the development of hard palustrine carbonate crust. At the advent of aridity, the whole system of Al Dibdibba alluvial fan was subjected to deflation. This resulted in reversing the paleotopography of the hard crusted palustrine depressions into carbonate capped domal hills.

  9. Study on Characterization Methods of Groundwater Lateral Flow Boundary Condition Based on the Nested Model- A Case Study of Groundwater Numerical Simulation of Nianpanshan Alluvial Plain in Hubei Province%基于嵌套模型的地下水侧向径流边界刻画方法研究--以湖北碾盘山冲积平原地下水数值模拟为例

    Institute of Scientific and Technical Information of China (English)

    汪祯宸; 陈植华; 徐栋; 彭康

    2016-01-01

    侧向径流边界的刻画方法是地下水数值模拟中的关键问题。以湖北碾盘山汉江水利水电枢纽工程为例,基于有限单元法和嵌套模型的水量转换方法,分别建立包括完整水文地质单元的区域模型和仅包含汉水Ⅰ级阶地的平原区模型;通过区域模型的分区水均衡运算,计算平原区侧向径流边界的径流量,并以区域模型水均衡为框架,分别采用二类流量边界和一类水头边界刻画侧向径流边界,建立了平原区模型;深入分析区域模型和平原区模型间参数和水量的转换关系,并对比了两类边界条件刻画方法的优缺点和适用条件。结果表明:采用嵌套模型能够得到较为准确的地下水侧向径流量;在平原区模型中采用二类流量边界刻画侧向径流边界有利于提高平原区模型的精度和稳定性;边界条件除具有双重含义外还具有双重特征,在模型建立过程中应充分认识边界条件的位置特征和数量特征,并合理概化。%Lateral flow boundary condition is a key issue in numerical simulation of ground water.Taking Nianpans-han hydropower proj ect in Hubei as an example,based on the finite element method and the water transformation of the nested model,this paper sets up a regional model which contains a complete hydrogeological unit and a plain terrain model which only covers theⅠlevel terrain of Han River.Through water balance calculation in different sec-tions of the regional model,the paper confirms the flux of the lateral flow boundary.Then,in the regime of the re-gional water balance,the paper establishes the plain terrain model respectively with the lateral flow boundary depic-ted by the Dirichlet boundary condition and the Neumann boundary condition.Next,the paper analyzes the relation-ship between the two models both in model parameters and water transformation relations,and compares the pros and cons and applicable conditions

  10. Turnover Rates of Fall Migrating Pectoral Sandpipers Through the Lower Mississippi Alluvial Valley

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Mississippi Alluvial Valley (MA V) is the historic alluvial floodplain of the Lower Mississippi River. Most of the MAV is located in Arkansas, Louisiana, and...

  11. APPLICABILITY OF THE BEND DEVELOPMENT THEORY IN NATURAL ALLUVIAL RIVERS

    Institute of Scientific and Technical Information of China (English)

    M.M.RAHMAN; M.A.HAQUE; M.M.HOQUE

    2002-01-01

    The theoretical conditions for the bend development or attenuation have been reviewed and tested for a study reach of the Meghna river.The field observations in the natural alluvial meander do not support the theories developed for bend development.The limitations of the theory to apply in the natural meandering river are discussed.

  12. Contrasting soils and landscapes of the Piedmont and Coastal Plain, eastern United States

    Science.gov (United States)

    Markewich, H.W.; Pavich, M.J.; Buell, G.R.

    1990-01-01

    The Piedmont and Coastal Plain physiographic provinces comprise 80 percent of the Atlantic Coastal states from New Jersey to Georgia. The provinces are climatically similar. The soil moisture regime is udic. The soil temperature regime is typically thermic from Virginia through Georgia, although it is mesic at altitudes above 400 m in Georgia and above 320 m in Virginia. The soil temperature regime is mesic for the Piedmont and Coastal Plain from Maryland through New Jersey. The tightly folded, structurally complex crystalline rocks of the Piedmont and the gently dipping "layer-cake" clastic sedimentary rocks and sediments of the Coastal Plain respond differently to weathering, pedogenesis, and erosion. The different responses result in two physiographically contrasting terrains; each has distinctive near-surface hydrology, regolith, drainage morphology, and morphometry. The Piedmont is predominantly an erosional terrain. Interfluves are as narrow as 0.5 to 2 km, and are convex upward. Valleys are as narrow as 0.1 to 0.5 km and generally V-shaped in cross section. Alluvial terraces are rare and discontinuous. Soils in the Piedmont are typically less than 1 m thick, have less sand and more clay than Coastal Plain soils, and generally have not developed sandy epipedons. Infiltration rates for Piedmont soils are low at 6-15 cm/h. The soil/saprolite, soil/rock, and saprolite/rock boundaries are distinct (can be placed within 10 cm) and are characterized by ponding and/or lateral movement of water. Water movement through soil into saprolite, and from saprolite into rock, is along joints, foliation, bedding planes and faults. Soils and isotopic data indicate residence times consistent with a Pleistocene age for most Piedmont soils. The Coastal Plain is both an erosional and a constructional terrain. Interfluves commonly are broader than 2 km and are flat. Valleys are commonly as wide as 1 km to greater than 10 km, and contain numerous alluvial and estuarine terrace

  13. Geohazards (floods and landslides) in the Ndop plain, Cameroon volcanic line

    Science.gov (United States)

    Wotchoko, Pierre; Bardintzeff, Jacques-Marie; Itiga, Zénon; Nkouathio, David Guimolaire; Guedjeo, Christian Suh; Ngnoupeck, Gerald; Dongmo, Armand Kagou; Wandji, Pierre

    2016-07-01

    The Ndop Plain, located along the Cameroon Volcanic Line (CVL), is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually) and landslides (occasionally) occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people) tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide) maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered. The hazard maps revealed that 25% of the area is exposed to flood hazard (13% exposed to high flood hazard, 12% to moderate) and 5% of the area is exposed to landslide hazard (2% exposed to high landslide hazard, 3% to moderate). Some mitigation measures for floods (building of artificial levees, raising foundations of buildings and the meticulous regulation of the flood guards at Bamendjing Dam) and landslides (slope terracing, planting of trees, and building retaining walls) are proposed.

  14. Specific yield, High Plains aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents specific-yield ranges in the High Plains aquifer of the United States. The High Plains aquifer underlies 112.6 million acres (176,000...

  15. Physical and microbiological properties of alluvial calcareous Çumra province soils (Central Anatolia, Turkey

    Directory of Open Access Journals (Sweden)

    Ahmet Sami Erol

    2015-04-01

    Full Text Available Alluvial calcareous soils in Central Anatolia (Konya province, Çumra district has a heavy granulometric composition (average clay, low organic carbon content (less than 1%, but stable pore space structure and favorable agrophysical properties. Studies of the water regime in drip irrigation confirm favorable hydrological properties of these soils. It is assumed that the favorable structure of the pore space due to vigorous activity a large and diverse soil biota. Four phyla dominate in soil biota, among which predominate Actinobacteria. The higher (Streptomyces, and lower (three species Rhodococcus actinobacteria are predominant in large amounts as a part of this phyla. Large biodiversity at a sufficiently high bacteria richness formed the structure of the microbial community that contribute to the balanced production of specific metabolites, including gases (CO2, N2, which allows the soil to function actively, preventing compaction of the pore space and maintaining optimal density, porosity, hydrologic properties of the studied silty clay soils. m the uppermost soil horizons. Analyses of heavy mineral fraction show presence of metamorphic and igneous minerals which indicate participation of weathering products from other rock types in the nearby area. The types of heavy minerals in soils depend more on composition of parent rocks and geomorphic position than on climate type. Soils from Nova Lovcha show similar composition, but the quantity of goethite and hematite significantly increase in soil from plain. Typical high-metamorphic minerals as andalusite, kyanite and sillimanite present only in Nova Lovcha, while garnet dominates in Petrovo and opaque minerals - in Dobrostan. Red soils, formed on slopes, where erosion prevails over accumulation, contain more illite, smectite and vermiculite-smectite, and very few or no kaolinite, whereas the kaolinite is dominant in soils formed on plain. The mineralogical composition of clays in different

  16. Generalized potentiometric-surface map of the High Plains aquifer in Wyoming, 1981

    Science.gov (United States)

    Avery, Charles; Pettijohn, Robert A.

    1984-01-01

    A potentiometric-surface map shows the general configuration of the water surface for the High Plains Aquifer, which is composed of Oligocene age and younger rocks in southeastern Wyoming. The potentiometric contours are shown at 100-foot intervals on a map at a scale of 1:250,000. The High Plains Aquifer in Wyoming underlies an area of 8,190 square miles and geologically consists of the White River Formation of Oligocene age, the Arikaree Formation of early Miocene age, the Ogallala Formation of late Miocene age, and alluvial deposits of Quaternary age. The altitude of the potentiometric surface declines from about 7 ,100 feet in southwestern Laramie County to about 4,100 feet in eastern Goshen County. Typically, the slope is between 20 and 30 feet per mile; the general direction of flow is eastward. (USGS)

  17. Reconstruction of the Friuli Venezia Giulia Plain aquifers

    Science.gov (United States)

    Calligaris, Chiara; Cimolino, Aurelie; Cucchi, Franco; Deana, Alberto; Treu, Francesco; Zini, Luca

    2010-05-01

    The constantly increasing of water demand for human consumptions has necessitated a reconstruction of the hydrogeologic characteristics and properties as well isotopic features of the aquifers of the Friuli Venezia Giulia Plain (FP). The DiSGAM and DICA have been engaged by the Hydraulic Survey of the FVG Region in order to coordinate an integrated study finalized to the FP confined and unconfined aquifer geometries reconstruction and to provide guide-lines for water rational exploitation (Agreement D.G.R. n. 1827 dd. 27.07.2007). The Friuli Venezia Giulia Plain, located in the northeastern sector of Italy, hosts well developed Plio-Quaternary unconfined and confined alluvial aquifers. The main surface drainage of the Plain is the Tagliamento River. The regional hydrogeological situation is characterized in the north by an extensive alluvial unconfined aquifer mostly contained in carbonate gravels. This area extends from the Pre-Alps to the resurgence belt. The resurgence belt is 2 to 8 km wide and 80 kilometres long. In this area the water table intersects the topographic surface forming numerous plain springs and rivers. The resurgence belt sets a geohydrological boundary between the Upper and Lower Friulian Plain. In this strip the unconfined aquifer changes into a multi-layered confined that reach a thickness of up to 500 m with a progressive increase in a westward direction towards the Adriatic Sea. In order to define underground aquifer relations and patterns, more than 1800 stratigraphic columns have been collected from different public departments water well database. Well logs have been georeferred, missing elevations calculated by regional DTM, possible correspondences controlled and datasets updated. In order to better correlate spatial data, an unique implemented lithostratigraphy legend has been created from present different ones; it is composed of: Lithological Entries (relating lithology and granulometric features; permeability linked different

  18. Radon hazard in shallow groundwaters II: Dry season fracture drainage and alluvial fan upwelling

    Energy Technology Data Exchange (ETDEWEB)

    Tommasone, F. Pascale [Office of Civil Protection, Meteorology, Climatology and Natural Hazards, Piazza Municipio, 81051 Pietramelara, Caserta (Italy); De Francesco, S., E-mail: stefano.defrancesco@unina2.it [Department of Environmental Sciences, University of Caserta, Via Vivaldi, 43, 81100 Caserta (Italy); Cuoco, E.; Verrengia, G.; Santoro, D. [Department of Environmental Sciences, University of Caserta, Via Vivaldi, 43, 81100 Caserta (Italy); Tedesco, D. [Department of Environmental Sciences, University of Caserta, Via Vivaldi, 43, 81100 Caserta (Italy); C.N.R. (Italian National Council), Institute of Environmental Geology and Geological Engineering, Piazzale Aldo Moro, 00100 Roma (Italy)

    2011-08-15

    {sup 222}Rn concentrations have been measured in a well located on the edge of a large Pleistocene-Holocene fan and belonging to the shallow pyroclastic aquifer of the Pietramelara Plain, southern Italy. The aim of this study has been both to characterise the hydrological inputs that determine the influx of {sup 222}Rn to the shallow aquifer and to understand the correlations between {sup 222}Rn, major ions, physical-chemical parameters and rainfall. Results obtained from the time series indicate that the studied well shows a {sup 222}Rn variability that is inconsistent with a mechanism of pure hydrological amplification, such as described in Radon hazard in shallow groundwaters: Amplification and long term variability induced by rainfall (De Francesco et al., 2010a). On the contrary, in this well hydrological amplification appears to be mainly tied to the upwelling of alluvial fan waters, rich in radon, in response to pistoning from recharge in the carbonate substrate. This upwelling of alluvial fan waters occurs during almost the whole period of the annual recharge and is also responsible of the constant increase in {sup 222}Rn levels during the autumn-spring period, when both the water table level and weekly rainfall totals drop. Furthermore, a rapid delivery mechanism for {sup 222}Rn likely operates through fracture drainage in concomitance with the very first late summer-early autumn rains, when rainfall totals appear largely insufficient to saturate the soil storage capacity. Results obtained from this study appear to be particularly significant in both radon hazard zoning in relation to the shallow aquifer and possibly also for indoor radon, owing to possible shallow aquifer-soil-building exchanges. Moreover, both the spike-like events and the long wave monthly scale background fluctuations detected can also have potential significance in interpreting {sup 222}Rn time series data as seismic and/or volcanic precursors. Finally, {sup 222}Rn has proved to be an

  19. The use of O, H and Sr isotopes and carbamazepine to identify the origin of water bodies supplying a shallow alluvial aquifer

    Science.gov (United States)

    Sassine, Lara; Le Gal La Salle, Corinne; Lancelot, Joël; Verdoux, Patrick

    2014-05-01

    Alluvial aquifers are of great socio-economic importance in France since they supply 82% of drinking water production, though they reveal to be very vulnerable to pesticides and emerging organic contaminants. The aim of this work is to identify the origin of water bodies which contribute to the recharge of an alluvial aquifer for a better understanding of its hydrochemistry and transfer of contaminants therein. The study is based on an isotopic and geochemical tracers approach, including major elements, trace elements (Br, Sr),and isotopes (δ18O, δ2H, 87Sr/86Sr), as well as organic molecules. Indeed, organic molecules such as pharmaceutical compounds, more precisely carbamazepine and caffeine, have shown their use as indicators of surface water in groundwater. The study area is a partially-confined shallow alluvial aquifer, the so-called Vistrenque aquifer, located at 15 km from the Mediterranean Sea, in the Quaternary alluviums deposited by an ancient arm of the Rhône River, in Southern France. This aquifer constitutes a shallow alluvial layer in a NE-SW graben structure. It is situated between a karst aquifer in lower Cretaceous limestones, on the NW border, and the Costières Plateau, on the SE border, having a similar geology as the Vistrenque. The alluvial plain is crossed by a surface water network with the Vistre as the main stream, and a canal used for irrigation essentially, the BRL canal, which is fed by the Rhône River. δ18O and δ2H allowed to differentiate the BRL canal water, depleted in heavy isotopes (δ2H = -71.5o vs V-SMOW), and the more enriched local rainwater (δ2H = -35.5o vs V-SMOW). In the Vistre surface water a binary mixing were evidenced with the BRL canal water and the rainwater, as end members. Then, in the Vistrenque groundwater both the BRL and the Vistre contributions could be identified, as they still show contrasting signature with local recharge. This allows to highlight the surface water contribution to a heavily exploited

  20. Lateral groundwater inflows into alluvial aquifers of main alpine valleys

    Science.gov (United States)

    Burger, Ulrich

    2015-04-01

    In alpine regions the topography is mainly characterised by deep incised valleys, mountain slopes and ridges. Usually the main valleys contain aquifers in alluvial soft rock. Lateral these aquifers are confined by mountainous hard rock slopes covered by heterogeneous sediments with different thickness. The slopes can be incised by lateral valleys. Numerical models for the main alluvial aquifers ask for lateral hydrogeological boundaries. Usually no flow boundaries or Constant head Boundaries are used, even if the lateral inflows to the main aquifers are rarely known. In this example a data set for a detailed investigated and monitored area is studied to give an answer on the location and the quantification of these lateral subsurface inflows. The study area is a typical main alpine valley with a thick alluvial aquifer (appr. 120m thick), lateral confined by granite, covered at the base of the steep slopes by quaternary sediments (Burger at al. 2012). The study consists of several steps 1.) Analytical calculation of the inflows on the base of investigated and monitored 2d profiles along fault zones (Perello et al 2013) which pinch out in the main valley 2.) Analytical models along typical W-dipping slopes with monitored slope springs 3.) Evaluating temperature and electrical conductivity profiles measured in approx. 30 groundwater wells in the alluvial aquifers and along the slopes to locate main lateral subsurface inflows 4.) Output of a regional model used for the hydrogeological back analyses of the excavation of a tunnel (Baietto et al. 2014) 5.) Output of a local numerical model calibrated with a monitoring dataset and results of a pumping test of big scale (450l/s for 10days) Results of these analyses are shown to locate and quantify the lateral groundwater inflows in the main alluvial aquifer. References Baietto A., Burger U., Perello P. (2014): Hydrogeological modelling applications in tunnel excavations: examples from tunnel excavations in granitic rocks

  1. Southeastern Coastal Plain aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Southeastern Coastal Plain aquifer system in Kentucky, Tennessee, Mississippi, Alabama, Georgia, and South Carolina.

  2. DEMOGRAPHIC VULNERABILITIES IN TECUCI PLAIN

    Directory of Open Access Journals (Sweden)

    Iulian Adrian ŞORCARU

    2013-06-01

    Full Text Available The study focuses on analyzing and mapping 8 indicators considered to best reflect the demographic vulnerability in Tecuci Plain in the year 2010 and proposes a model of aggregation which finally allows us to distinguish three major types of demographic vulnerability (low, medium and high. Mapping the final values also shows significant disparities in the territorial administrative units that broadly overlap the plain, the most vulnerable being Tecuci city and the peripheral communes, towards Vrancea and Vaslui Counties.

  3. Alluvial fan flooding in the Department of Pocito, Province of San Juan, Argentina

    Institute of Scientific and Technical Information of China (English)

    LauraPatriciaPerucca; JuanParedes

    2004-01-01

    The study consists of the identification of landforms subject to alluvial fan flooding in active sectors of the Zonda range piedmont. In the Department of Pocito, located about 5 km southwest of San Juan City, a series of alluvial fans have been identified. These alluvial fans are located downstream of the natural drainage basins covering an area of approximately 130 km2 towards the eastern slopes of the Zonda range at a median elevation of 2,000 m a.s.l.

  4. Alluvial Diamond Resource Potential and Production Capacity Assessment of Ghana

    Science.gov (United States)

    Chirico, Peter G.; Malpeli, Katherine C.; Anum, Solomon; Phillips, Emily C.

    2010-01-01

    In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by both diamond-producing and diamond-importing countries. Over 70 countries were included as members at the end of 2007. To prevent trade in 'conflict' diamonds while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was to assess the alluvial diamond resource endowment and current production capacity of the alluvial diamond-mining sector in Ghana. A modified volume and grade methodology was used to estimate the remaining diamond reserves within the Birim and Bonsa diamond fields. The production capacity of the sector was estimated using a formulaic expression of the number of workers reported in the sector, their productivity, and the average grade of deposits mined. This study estimates that there are approximately 91,600,000 carats of alluvial diamonds remaining in both the Birim and Bonsa diamond fields: 89,000,000 carats in the Birim and 2,600,000 carats in the Bonsa. Production capacity is calculated to be 765,000 carats per year, based on the formula used and available data on the number of workers and worker productivity. Annual production is highly dependent on the international diamond market and prices, the numbers of seasonal workers actively mining in the sector, and

  5. Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding

    Science.gov (United States)

    Young, M. E.; de Bruijn, R. G. M.; Al-Ismaily, A. Salim

    One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary marine sediments and Cretaceous ophiolite were mapped with seismic reflection data, recorded originally for oil exploration. The base of the alluvium dips northward from the foothills of the Northern Oman Mountains, reaching a maximum depth of 2000m at the coast. The varying facies of the alluvium are grossly characterised by different, overlapping ranges of electrical resistivity, depending largely on the clay content and degree of cementation. Resistivities near the coast are reduced by saline intrusion. These variations of resistivity were mapped with time-domain electromagnetic sounding along 400km of profile, to distinguish among the three zones of the alluvial aquifer. The wedge of saline intrusion was also delineated, up to 10km from the coast. The thickness of the saturated gravel aquifer ranges from 20-160m in an area greater than 600km2. Résumé Un tiers de la population d'Oman est alimenté par de l'eau souterraine pompée dans les alluvions de la plaine de Batinah, sur la côte du golfe d'Oman. Des techniques d'exploration géophysique profonde ont été mises en oeuvre pour déterminer la profondeur et la nature des alluvions et les limites de l'aquifère. La base et les contrôles structuraux du bassin alluvial au contact des sédiments marins tertiaires et des ophiolites crétacées ont été cartographiés à partir des données de sismique réflexion obtenues à l'origine pour la recherche pétrolière. La base des alluvions plonge vers le nord à partir du piémont du massif septentrional d'Oman, pour atteindre une profondeur maximale de 2000m sur la côte. Les divers faciès alluviaux

  6. Co-contamination of As and F in alluvial aquifer

    Science.gov (United States)

    Kim, S.; Kim, K.; Kim, B.; Zhu, W.; Lee, E.; Ko, K.

    2010-12-01

    Co-contamination of As and F is frequently observed in alluvial aquifers of many countries including Argentina, Mexico, China, and Pakistan. However, processes causing this phenomenon are still poorly understood. In arid or semi-arid areas, the aquifers are generally under oxidizing condition and As and F show a good correlation. In contrast, groundwaters under reducing condition generally show a poorer correlation. In this study, we explored the geochemical mechanisms causing the co-contamination of As and F and their poorer correlation in the reducing environment by investigating alluvial groundwaters of the Mankyeong River floodplain, Korea. For this study, we collected 72 groundwater samples from 42 shallow wells placed into the alluvial aquifer. Desorption experiments using soils collected from the study area were also performed. Groundwater chemistry data showed that waters are under strong reducing condition and the reductive dissolution of Fe oxides was the main process increasing As concentration in groundwaters. The co-contamination was also observed in the study area and F did not show a good correlation with As. F showed concentrations increasing with pH. Desorption experiments also showed the dependences of As and F on pH. The experiments using soils treated with Na citrate-NaHCO3-dithonite solution indicated that iron oxides were the main phases hosting both As and F in soils. In our study area, pH of groundwaters increases due to a series of reduction reactions, and which increased F concentration by desorption from iron oxides. This result suggests that sharing the same adsorption hosts and the pH increased by reduction reactions are the main reason for the co-occurrence of As and F in alluvial groundwater under reducing environments. The lack of correlation between As and F was derived by the precipitation of As as sulfides in sulfate reducing condition. However, the correlation could be much better in the oxidizing condition because As released

  7. Analysis of cutin and suberin biomarker patterns in alluvial sedi-ments

    Science.gov (United States)

    Herschbach, Jennifer; Sesterheim, Anna; König, Frauke; Fuchs, Elmar

    2015-04-01

    Cutin and suberin are the primary source of hydrolysable aliphatic lipid polyesters in soil organic matter (SOM). They are known as geochemical biomarkers to estimate the contribution of different plant species and tissues to SOM. Despite their potential as biomarkers, cutin and suberin have received less attention as flood plain sediment biomarkers. The objectives of this study were to investigate the efficiency of cutin and suberin as biomarkers in floodplains. Therefore similarities between the lipid pattern in alluvial sediments and in the actual vegetation were considered. Lipids of plant tissues (roots, twigs, leaves) from different species (reed (e.g. Phalaris arun-diacea), Salix alba, Ulmus laevis and grassland (e.g. Carex spec.)) and of the un-derlying soils and sediments were obtained and investigated at four sites in the nature reserve Knoblauchsaue (Hessen, Germany). The four sampling sites differ not only with respect to their vegetation, but also within their distance to the river Rhine. Cutin and suberin monomers of plants and soils were analysed by alkaline hydrolysis, methylation and acetylation and subsequent gas chromatography-mass spectrometry. Resulting lipid patterns were specific for the appropriate plant species and tissues. However, the traceability of single selected lipids was decreasing alongside the soil profile, with the exception of monomers in softwood floodplain soils. Selected tissue specific lipid ratios showed a higher traceability due to strong attributions of lipid ratios in soils and roots of U. laevis and Carex spec. and in leaves of U. laevis and S. alba. In contrast, there was no accordance between the suberin specific lipid ratios in soils and roots of S. alba and P. arundiacea. The most robust interpretations were afforded when a set of multiple biomarkers (i.e. a combination of free lipid ratios and ratios of hydrolysable lipids) was used to collectively reconstruct the source vegetation of different sediment layers.

  8. Potential geo-ecological impacts of the proposed Danube–Oder–Elbe Canal on alluvial landscapes in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Machar Ivo

    2015-06-01

    Full Text Available The project of a canal connecting the three major Central European Rivers: the Danube, Oder and Elbe, is incorporated into a planned trans-European transport network system. Geographically, the course of the planned canal stretches into the territory of four Central European countries, predominantly that of the Czech Republic. The environmental impacts of the potential construction and operation of the Danube–Oder–Elbe (DOE Canal is currently widely discussed by experts from various fields. This paper aims to assess some potential impacts of the canal on the alluvial landscapes in the Czech Republic. The method of geo-ecological assessment presented here applies GIS analyses at the larger landscape scale. The results of the geo-ecological assessment of potential impacts of the DOE Canal on the land-use of river floodplains, the fluvial dynamics of streams and the extent of their alluvial plains, and the quantified DOE Canal impact on protected areas and groundwater sources, are presented. The hydrological impact of the DOE Canal will affect a total of 1,975.4 km2 of river basins in the Czech Republic. The DOE Canal will affect 157 sites significant from the perspective of landscape and nature conservation, 7 nature parks and 113 existing water points which are used as groundwater sources. The results show that the most significant disruption of fluvial dynamics of the stream sediment regime would occur in the Protected Landscape Area of Litovelské Pomoraví. In general, the geo-ecological impact of the DOE Canal on the landscape will be very important.

  9. Integrative geomorphological mapping approach for reconstructing meso-scale alluvial fan palaeoenvironments at Alborz southern foothill, Damghan basin, Iran

    Science.gov (United States)

    Büdel, Christian; Majid Padashi, Seyed; Baumhauer, Roland

    2013-04-01

    Alluvial fans and aprons are common depositional features in general Iranian geomorphology. The countries major cities as well as settlements and surrounding area have often been developed and been built up on this Quaternary sediment covers. Hence they periodically face the effects of varying fluvial and slope-fluvial activity occurring as part of this geosystem. The Geological Survey of Iran therefore supports considerable efforts in Quaternary studies yielding to a selection of detailed mapped Quaternary landscapes. The studied geomorphologic structures which are settled up around an endorheic basin in Semnan Province represent a typical type of landform configuration in the area. A 12-km-transect was laid across this basin and range formation. It is oriented in north-south direction from the southern saltpan, called "Kavir-e-Haj Aligholi"/"Chah-e-Jam" ("Damghan Kavir"), across a vast sandy braided river plain, which is entering from the north east direction of the city of Shahroud. At its northern rim it covers alluvial sediment bodies, which are mainly constituted by broad alluvial aprons, fed by watersheds in Alborz Mountains and having their genetic origins in Mio-/Pliocene times. During this study a fully analytical mapping system was used for developing a geodatabase capable of integrating geomorphological analyses. Therefore the system must provide proper differentiation of form, material and process elements as well as geometric separation. Hence the German GMK25 system was set up and slightly modified to fit to the specific project demands. Due to its structure it offers most sophisticated standards and scale independent hierarchies, which fit very well to the software-determinated possibilities of advanced geodatabase applications. One of the main aspects of mapping Quaternary sediments and structures is to acquire a proper description and systematic correlation and categorization of the belonging mapping-objects. Therefore the team from GSI and

  10. Timing and nature of alluvial fan development along the Chajnantor Plateau, northern Chile

    Science.gov (United States)

    Cesta, Jason M.; Ward, Dylan J.

    2016-11-01

    Alluvial systems in the Atacama Desert provide a unique opportunity to elucidate the sedimentary response to climate variability, particularly changes in precipitation, in hyperarid environments. Alluvial fans along the eastern margin of the Salar de Atacama, adjacent to the Chajnantor Plateau in the Atacama Desert of northern Chile, provide an archive of climate-modulated sediment transfer and erosion at an extreme of Earth's climate. Three regional alluvial fan surfaces (Qf1 [oldest] to Qf3 [youngest]) were mapped along the western flank of the Chajnantor Plateau. The alluvial fans were examined with geomorphic and terrestrial cosmogenic 36Cl surface exposure dating methods to define the timing of alluvial fan formation and to determine the role of climatic processes on fan development in a hyperarid environment. Alluvial fans in the study area are comprised of hyperconcentrated flow and boulder-rich debris flow deposits that reflect deposition transitioning between cohesive and noncohesive regimes. Alluvial fan surfaces yield exposure ages that range from 49.6 ± 4.4 to 194 ± 12 ka, while debris flow boulders yield exposure ages ranging from 12.4 ± 2.1 to 229 ± 53 ka. Cosmogenic 36Cl exposure ages indicate that abandonment of alluvial fan surfaces Qf1, Qf2, and Qf3 date to 175 ± 22.6 ka (MIS 6), 134.5 ± 9.18 ka (MIS 6), and 20.07 ± 6.26 ka (MIS 2), respectively. A 36Cl concentration-depth profile through alluvial fan Qf1 suggests a simple depositional history with minimal nuclide inheritance implying relatively rapid aggradation (6 m in ca. 25 kyr) followed by surface abandonment ca. 180-200 ka. Our data support a strong climatic control on alluvial fan evolution in the region, and we propose that the alluvial fans along the margins of the Salar de Atacama form according to the humid model of fan formation.

  11. Comparison of high-resolution P- and SH-wave reflection seismic data in alluvial and pyroclastic deposits in Indonesia

    Science.gov (United States)

    Wiyono, Wiyono; Polom, Ulrich; Krawczyk, Charlotte M.

    2013-04-01

    Seismic reflection is one of the stable methods to investigate subsurface conditions. However, there are still many unresolved issues, especially for areas with specific and complex geological environments. Here, each location has an own characteristic due to material compounds and the geological structure. We acquired high-resolution, P-and SH-wave seismic reflection profiles at two different locations in Indonesia. The first location was in Semarang (Central Java) and the second one was in Tiris (East Java). The first region is located on an alluvial plain with thick alluvial deposits of more than 100 m estimated thickness, and the second location was located on pyroclastic deposit material. The seismic measurements for both locations were carried out using a 48-channel recording system (14-Hz P-wave, 10-Hz SH-wave geophones) with geophone intervals of 5 m (P-waves) and 1 m (SH-waves), respectively. The seismic source for the P-wave was a ca. 4 kg sledge hammer which generated a seismic signal by by hitting on an aluminum plate of 30x30 cm, whereas the SH-wave source was a mini-vibrator ELVIS (Electrodynamic Vibrator System), version 3. Thirteen seismic profiles at Semarang and eighth profiles at Tiris were acquired. The results of seismic data in Semarang show fair to good seismic records for both P-and SH-waves. The raw data contain high signal-to-noise-ratio. Many clear reflectors can be detected. The P-wave data shows reflectors down to 250 ms two-way time while the SH-wave records show seismic events up to 600 ms two-way time. This result is in strong contrast to the seismic data result from the Tiris region. The P-wave data show very low signal to noise ratio, there is no reflection signal visible, only the surface waves and the ambient noise from the surrounding area are visible. The SH-waves give a fair to good result which enables reflector detection down to 300 ms two-way time. The results from the two seismic campaigns show that SH-wave reflection

  12. Geotechnical mapping for alluvial fan deposits controlled by active faults: a case study in the Erzurum, NE Turkey

    Science.gov (United States)

    Yarbasi, Necmi; Kalkan, Ekrem

    2009-08-01

    Erzurum, the biggest city of Eastern Anatolia Region in the Turkey, is located in Karasu Plain. Karasu Plain, located on the central segment of the Erzurum Fault Zone, is an intermountain sedimentary basin with a Miocene-Quaternary volcanic basement, andesitic-basaltic lava flows and fissure eruptions of basaltic lava. It was filled in the early Quaternary by lacustrine fan-delta deposits. The basin is characterized by NNE-SSW trending sinistral wrench faults on its eastern margin and ENE-WSW trending reverse faults on its southern margin. Both systems of active faults intersect very near to Erzurum, which is considered to be the most likely site for the epicenter of a probable future large earthquake. Historical records of destructive earthquakes, morphotectonic features formed by paleo-seismic events and instrument seismic data of region indicate to a very high regional seismicity. The residential areas of Erzurum are located on thick alluvial fan deposits forming under the control of faults on the central segment of the Erzurum Fault Zone, which is one of the most active fault belts of the East Anatolian Region. Over time, the housing estates of city such as Yenisehir and Yildizkent have been expanded toward to the west and southwest part of Erzurum as a consequence of rapid and massive construction during the last 30 years. Geotechnical investigation has therefore been undertaken the residential areas of city in order to characterize geotechnical properties over the varied lithologies examine the potential for geotechnical mapping and assess the foundation conditions of the present and future settlement areas. The geological field observations and operations have been performed to make the soil sampling and characterize the lateral and vertical changes in thickness of the alluvial deposits in trenches, excavations and deep holes with 6-12 m sections. The soil samples have been subjected to a series of tests under laboratory conditions to obtain physical and

  13. Autogenic dynamics of alluvial fans in endorheic basins: Outcrop examples and stratigraphic significance

    NARCIS (Netherlands)

    Ventra, D.; Nichols, G.J.

    2014-01-01

    Alluvial fans are relatively simple depositional systems, due to the direct coupling of sediment sources and adjacent accumulation areas. Nonetheless, general models of alluvial-fan evolution and stratigraphy remain elusive, due to the great sensitivity of such systems to allogenic controls and thei

  14. FUTURE STUDIES AT PENA BLANCA: RADIONUCLIDE MIGRATION IN THE VADOSE ZONE OF AN ALLUVIAL FAN

    Energy Technology Data Exchange (ETDEWEB)

    P. Goodell; J. Walton; P.J. Rodriguez

    2005-07-11

    The pathway to the accessible environment at Yucca Mountain contains volcanic rocks and alluvial fill. Transport properties in alluvial fill, specifically retardation and dispersivity, may be significant in determining the overall performance of the repository. Prior relevant studies, with the exception of the Nye County Tracer Test, are almost entirely in bedrock material. The proposed study will provide field data on radionuclide migration in alluvial material. High grade uranium ore was mined at the Nopal I deposit. This mined ore (60,000 tons) was moved in 1994 to its present site as open piles on an alluvial fan in the Boquilla Colorada Microbasin. Precipitation is approximately 20 cm/year, and has caused migration of radionuclides into the subsurface. We propose partial removal of an ore pile, excavation into the alluvial fan, sampling, and determination of radionuclide mobilities from the uranium decay chain. The proposed research would be taking advantage of a unique opportunity with a known time frame for migration.

  15. Comparison of planform multi-channel network characteristics of alluvial and bedrock constrained large rivers

    Science.gov (United States)

    Carling, P. A.; Meshkova, L.; Robinson, R. A.

    2011-12-01

    The Mekong River in northern Cambodia is an multi-channel mixed bedrock-alluvial river but it was poorly researched until present. Preliminary study of the Mekong geomorphology was conducted by gathering existing knowledge of its geological and tectonic settings, specific riparian vegetation and ancient alluvial terraces in which the river has incised since the Holocene. Altogether this process has allowed a geomorphological portrait of the river to be composed within the Quaternary context. Following this outline, the planform characteristics of the Mekong River network are compared, using analysis of channel network and islands configurations, with the fluvial patterns of the Orange River (South Africa), Upper Columbia River (Canada) and the Ganga River (India, Bangladesh). These rivers are selected as examples of multi-channel mixed bedrock alluvial, anastomosed alluvial and braided alluvial rivers respectively. Network parameters such as channel bifurcation angles asymmetry, sinuosity, braid intensity and island morphometric shape metrics are compared and contrasted between bedrock and alluvial systems. In addition, regional and local topographic trend surfaces produced for each river planform help explain the local changes in river direction and the degree of anastomosis, and distinguish the bedrock-alluvial rivers from the alluvial rivers. Variations between planform characteristics are to be explained by channel forming processes and in the case of mixed bedrock-alluvial rivers mediated by structural control. Channel metrics (derived at the reach-scale) provide some discrimination between different multi-channel patterns but are not always robust when considered singly. In contrast, island shape metrics (obtained at subreach-scale) allow robust discrimination between alluvial and bedrock systems.

  16. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  17. Characterization of alluvial aquifers by multiscale hydrostratigraphic interpretation of DC resistivity data

    Science.gov (United States)

    Mele, Mauro; Bersezio, Riccardo; Giudici, Mauro

    2010-05-01

    The characterization of aquifer heterogeneity plays a key role for the 3-D modelling of conductivity (K) distribution in the subsurface of alluvial plains. DC methods such as Vertical Electrical Soundings (VES) and Electrical Resistivity Ground Imaging (ERGI) yield respectively the 1-D and 2-D resistivity (ρ) distribution in the ground and are often applied in hydrogeology because ρ is controlled by the prevailing process of current conduction ('shale' vs. electrolytic conduction) determined by the occurrence of fine-grained sediments and saline groundwater. Assuming that the sedimentary heterogeneity can be described with hierarchical elements at different scales (from hydrofacies to hydrostratigraphic systems) and recalling that the resolution of DC surveys decreases with depth, we propose an interpretation of the subsurface ρ distribution as a function of the hierarchical properties of aquifers (i.e., the vertical trends of facies with prevailing 'shale' or electrolytic conduction) with hydrostratigraphic constrains. A correlation between ρ and pore-fluid saturation and chemistry permits the use of resistivity as a 'proxy' of facies stacking. Our case-study is the Quaternary valley of palaeo-Sillaro extinct meandering river (Po plain, Italy). The local stratigraphy up to 80 m below ground surface consists of LGM sand-gravel point bar and channel bodies overlying: i) clay to fine sand aquitard of an Upper Pleistocene flood plain, ii) alternating gravel-sand aquifer bodies and fine sand to silty-clay drapes formed by Middle-Upper Pleistocene braiding to meandering depositional systems that developed above iii) a basal aquiclude of silty-clays. To interpret 1-D resistivity models obtained by 89 VES collected with Schlumberger array (maximum half-spacing 300 m) over an area of 30 km2, a Coarse-to-Fine (C/F) litho-textural ratio (particle size cut-off=0.30 mm) was used to classify hydrofacies. The variability of C/F was compared with the K and ρ values of

  18. 30 CFR 785.19 - Surface coal mining and reclamation operations on areas or adjacent to areas including alluvial...

    Science.gov (United States)

    2010-07-01

    ..., and evapotranspiration, relief, slope and density of drainage channels; (B) Factors contributing to... coal mining operation may affect this alluvial valley floor or waters that supply the alluvial valley... alluvial valley floor that would be affected by the surface coal mining operation is of such small...

  19. Alluvial architecture of the Holocene Rhine-Meuse delta (The Netherlands) and the Lower Mississippi Valley (U.S.A.)

    NARCIS (Netherlands)

    Gouw, M.J.P.

    2007-01-01

    Alluvial architecture describes the geometry, proportion, and spatial distribution of different types of fluvial deposits in an alluvial succession. Alluvial architecture is frequently subject of study, because natural resources commonly occur in ancient fluvial sequences. The ability of models to s

  20. Experimental determination of thermal properties of alluvial soil

    Science.gov (United States)

    Kulkarni, N. G.; Bhandarkar, U. V.; Puranik, B. P.; Rao, A. B.

    2016-12-01

    In the present work, thermal conductivity and specific heat of a particular type of alluvial soil used in brick making in a certain region of India (Karad, Maharashtra State) are experimentally determined for later use in the estimation of ground heat loss in clamp type kilns. These properties are determined simultaneously using the steady-state and the transient temperature data measured in the setup constructed for this purpose. Additionally, physical properties of the soil are experimentally determined for use with six models for the prediction of the thermal conductivity of soil. The predictions from the models are compared with the experimental data. A separate data fitting exercise revealed a small temperature dependence of the soil thermal conductivity on the soil mean temperature.

  1. Alluvial Fan Morphology, distribution and formation on Titan

    Science.gov (United States)

    Birch, S. P. D.; Hayes, A. G.; Howard, A. D.; Moore, J. M.; Radebaugh, J.

    2016-05-01

    Titan is a hydrologically active world, with dozens of alluvial fans that are evidence of sediment transport from high to low elevations. However, the distribution and requirements for the formation of fans on Titan are not well understood. We performed the first global survey of alluvial fans on Titan using Cassini Synthetic Aperture Radar (SAR) data, which cover 61% of Titan's surface. We identified 82 fans with areas ranging from 28 km2 to 27,000 km2. A significant fraction (∼60%) of the fans are restricted to latitudes of ±50-80°, suggesting that fluvial sediment transport may have been concentrated in the near-polar terrains in the geologically recent past. The density of fans is also found to be correlated with the latitudes predicted to have the highest precipitation rates by Titan Global Circulation Models. In equatorial regions, observable fans are not generally found in proximity to dune fields. Such observations suggest that sediment transport in these areas is dominated by aeolian transport mechanisms, though with some degree of recent equatorial fluvial activity. The fan area-drainage area relationship on Titan is more similar to that on Earth than on Mars, suggesting that the fans on Titan are smaller than what may be expected, and that the transport of bedload sediment is limited. We hypothesize that this has led to the development of a coarse gravel-lag deposit over much of Titan's surface. Such a model explains both the morphology of the fans and their latitudinal concentration, yielding insight into the sediment transport regimes that operate across Titan today.

  2. Alluvial terrace preservation in the Wet Tropics, northeast Queensland, Australia

    Science.gov (United States)

    Hughes, Kate; Croke, Jacky; Bartley, Rebecca; Thompson, Chris; Sharma, Ashneel

    2015-11-01

    Alluvial terraces provide a record of aggradation and incision and are studied to understand river response to changes in climate, tectonic activity, sea level, and factors internal to the river system. Terraces form in all climatic regions and in a range of geomorphic settings; however, relatively few studies have been undertaken in tectonically stable settings in the tropics. The preservation of alluvial terraces in a valley is driven by lateral channel adjustments, vertical incision, aggradation, and channel stability, processes that can be further understood through examining catchment force-resistance frameworks. This study maps and classifies terraces using soil type, surface elevation, sedimentology, and optically stimulated luminescence dating across five tropical catchments in northeast Queensland, Australia. This allowed for the identification of two terraces across the study catchments (T1, T2). The T1 terrace was abandoned ~ 13.9 ka with its subsequent removal occurring until ~ 7.4 ka. Abandonment of the T2 terrace occurred ~ 4.9 ka with removal occurring until ~ 1.2 ka. Differences in the spatial preservation of these terraces were described using an index of terrace preservation (TPI). Assessments of terrace remnant configuration highlighted three main types of terraces: paired, unpaired, and disconnected, indicating the importance of different processes driving preservation. Regional-scale variability in TPI was not strongly correlated with catchment-scale surrogate variables for drivers of terrace erosion and resistance. However, catchment-specific relationships between TPI and erosion-resistance variables were evident and are used here to explain the dominant processes driving preservation in these tropical settings. This study provides an important insight into terrace preservation in the tectonically stable, humid tropics and provides a framework for future research linking the timing of fluvial response to palaeoclimate change.

  3. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil

    Directory of Open Access Journals (Sweden)

    AC. Silva

    Full Text Available In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh, total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  4. Plain Polynomial Arithmetic on GPU

    Science.gov (United States)

    Anisul Haque, Sardar; Moreno Maza, Marc

    2012-10-01

    As for serial code on CPUs, parallel code on GPUs for dense polynomial arithmetic relies on a combination of asymptotically fast and plain algorithms. Those are employed for data of large and small size, respectively. Parallelizing both types of algorithms is required in order to achieve peak performances. In this paper, we show that the plain dense polynomial multiplication can be efficiently parallelized on GPUs. Remarkably, it outperforms (highly optimized) FFT-based multiplication up to degree 212 while on CPU the same threshold is usually at 26. We also report on a GPU implementation of the Euclidean Algorithm which is both work-efficient and runs in linear time for input polynomials up to degree 218 thus showing the performance of the GCD algorithm based on systolic arrays.

  5. Southern Great Plains Safety Orientation

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, John

    2014-05-01

    Welcome to the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ARM) Southern Great Plains (SGP) site. This U.S. Department of Energy (DOE) site is managed by Argonne National Laboratory (ANL). It is very important that all visitors comply with all DOE and ANL safety requirements, as well as those of the Occupational Safety and Health Administration (OSHA), the National Fire Protection Association, and the U.S. Environmental Protection Agency, and with other requirements as applicable.

  6. Magnetic properties of alluvial soils polluted with heavy metals

    Science.gov (United States)

    Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

    2012-04-01

    Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (Příbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on

  7. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

    Science.gov (United States)

    Gran, K. B.

    2015-12-01

    Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a

  8. Mississippi River Valley Alluvial Aquifer, Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Tennessee; 2006-2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Outcrop and subcrop extent of the Mississippi River Valley Alluvial Aquifer in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, and Tennessee.

  9. Seismic responses of a hemispherical alluvial valley to SV Waves: a three-dimensional analytical approximation

    Institute of Scientific and Technical Information of China (English)

    Chenggang Zhao; Jun Dong; Fuping Gao; D.-S.Jeng

    2006-01-01

    An analytical solution to the three-dimensional scattering and diffraction of plane SV-waves by a saturated hemispherical alluvial valley in elastic halfspace is obtained by using Fourier-Bessel series expansion technique.The hemispherical alluvial valley with saturated soil deposits is simulated with Biot's dynamic theory for saturated porous media.The following conclusions based on numerical results can be drawn:(1) there are a significant differences in the seismic response simulation between the previous single-phase models and the present two-phase model;(2)the normalized displacements on the free surface of the alluvial valley depend mainly on the incident wave angles,the dimensionless frequency of the incident SV waves and the porosity of sediments;(3)with the increase of the incident angle,the displacement distributions become more complicated,and the displacements on the free surface of the alluvial valley increase as the porosity of sediments increases.

  10. The Alluvial Fan Complex in Holden Crater: Implications for the Environment of Early Mars

    Science.gov (United States)

    Irwin, R. P.; Grant, J. A.; Howard, A. D.

    2008-03-01

    The alluvial fan complex in Holden crater is the largest deposit of this type on Mars and preserves topographic and sedimentary indicators of its formative environment around the Noachian/Hesperian transition.

  11. Clay Mineralogy of AN Alluvial Aquifer in a Mountainous, Semiarid Terrain, AN Example from Rifle, Colorado

    Science.gov (United States)

    Elliott, W. C.; Lim, D.; Zaunbrecher, L. K.; Pickering, R. A.; Williams, K. H.; Navarre-Sitchler, A.; Long, P. E.; Noel, V.; Bargar, J.; Qafoku, N. P.

    2015-12-01

    Alluvial sediments deposited along the Colorado River corridor in the semi-arid regions of central to western Colorado can be important hosts for legacy contamination including U, V, As and Se. These alluvial sediments host aquifers which are thought to provide important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface. Relatively little is known about the clay mineralogy of these alluvial aquifers and the parent alluvial sediments in spite of the fact that they commonly include lenses of silt-clay materials. These lenses are typically more reduced than coarser grained materials, but zones of reduced and more oxidized materials are present in these alluvial aquifer sediments. The clay mineralogy of the non-reduced parent alluvial sediments of the alluvial aquifer located in Rifle, CO (USA) is composed of chlorite, smectite, illite, kaolinite and quartz. The clay mineralogy of non-reduced fine-grained materials at Rifle are composed of the same suite of minerals found in the sediments plus a vermiculite-smectite intergrade that occurs near the bottom of the aquifer near the top of the Wasatch Formation. The clay mineral assemblages of the system reflect the mineralogically immature character of the source sediments. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate and suggestive of minimal transport of the alluvial sediments from their source areas. Chlorite, smectite, smectite-vermiculite intergrade, and illite are the likely phases involved in the sorption of organic carbon and related microbial redox transformations of metals in these sediments. Both the occurrence and abundance of chlorite, smectite-vermiculite, illite and smectite can therefore exert an important control on the contaminant fluxes and are important determinants of biogeofacies in mountainous, semiarid terrains.

  12. Diazotrophy in alluvial meadows of subarctic river systems.

    Directory of Open Access Journals (Sweden)

    Thomas H DeLuca

    Full Text Available There is currently limited understanding of the contribution of biological N2 fixation (diazotrophy to the N budget of large river systems. This natural source of N in boreal river systems may partially explain the sustained productivity of river floodplains in Northern Europe where winter fodder was harvested for centuries without fertilizer amendments. In much of the world, anthropogenic pollution and river regulation have nearly eliminated opportunities to study natural processes that shaped early nutrient dynamics of large river systems; however, pristine conditions in northern Fennoscandia allow for the retrospective evaluation of key biochemical processes of historical significance. We investigated biological N2 fixation (diazotrophy as a potential source of nitrogen fertility at 71 independent floodplain sites along 10 rivers and conducted seasonal and intensive analyses at a subset of these sites. Biological N2 fixation occurred in all floodplains, averaged 24.5 kg N ha(-1 yr(-1 and was down regulated from over 60 kg N ha(-1 yr(-1 to 0 kg N ha(-1 yr(-1 by river N pollution. A diversity of N2-fixing cyanobacteria was found to colonize surface detritus in the floodplains. The data provide evidence for N2 fixation to be a fundamental source of new N that may have sustained fertility at alluvial sites along subarctic rivers. Such data may have implications for the interpretation of ancient agricultural development and the design of contemporary low-input agroecosystems.

  13. Cobalt in alluvial Egyptian soils as affected by industrial activities

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Twenty-five surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted,moderately and highly polluted soils. The aim of this study was to evaluate total Co content in alluvial soils of Delta in Egypt using the delayed Neturen activation analysis technique (DNAA). The two prominent gamma ray lines at 1173.2 and 1332.5 keV was efficiently used for 60Co determination. Co content in non-polluted soil samples ranged between 13.12 to 23.20 ppm Co with an average of 18.16*4.38 ppm. Cobalt content in moderately polluted soils ranged between 26.5 to 30.00 ppm with an average of 28.3*1.3 ppm. The highest Co levels (ranged from 36 to 64.69 ppm with an average of 51.9*9.5); were observed in soil samples collected from, either highly polluted agricultural soils due to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  14. Defining 'plain language' in contemporary South Africa

    Directory of Open Access Journals (Sweden)

    Eleanor Cornelius

    2015-12-01

    Full Text Available Defining the concept ‘plain language’ has been hugely problematic since the origins of the so-called Plain Language Movement in the 1970s in the United States and elsewhere in the world. Definitions of ‘plain language’ abound, yet James (2008: 6 warns, in relation to plain language practitioners, that “we can’t yet call ourselves a coherent field, let alone a profession, while we offer such varying definitions of what we do”. Contemporary international definitions of ‘plain language’ are of three types: numerical (or formula-based, elements-focused, or outcomes-focused (Cheek 2010. In South Africa, protective legislation gave rise to a local definition of ‘plain language’ which was widely acclaimed for its comprehensiveness and practicality. From a textlinguistic angle, this article ruminates on the nature of the definition of ‘plain language’ in the National Credit Act (2005 and the Consumer Protection Act (2008, and critically appraises the value of the definition as a sharp and reliable conceptual tool for use by plain language practitioners – as applied linguists – in the absence of norms, standards or guidelines for the use of plain language in the consumer industry in contemporary South Africa.

  15. Paleoenvironmental interpretation of an ancient Arctic coastal plain: Integrated paleopedology and palynology from the Late Cretaceous (Maastrichtian) Prince Creek Formation, North Slope, Alaska, USA

    Science.gov (United States)

    McCarthy, P. J.; Flaig, P. P.; Fiorillo, A. R.

    2010-12-01

    The Cretaceous (Early Maastrichtian), dinosaur-bearing Prince Creek Formation, North Slope, Alaska, records high-latitude, alluvial sedimentation and soil formation on a low-lying, coastal plain during a greenhouse phase in Earth history. This study combines outcrop observations, micromorphology, geochemistry, and palynological analyses of paleosols in order to reconstruct local paleoenvironments of weakly developed, high-latitude coastal plain soils. Sediments of the Prince Creek Fm. include quartz- and chert-rich sandstone channels, and floodplains containing organic-rich siltstone and mudstone, carbonaceous shale, coal and ashfall deposits. Vertically stacked horizons of blocky-to-platy, drab-colored mudstone and siltstone with carbonaceous root-traces and mottled aggregates alternating with sandy units indicate that the development of compound and cumulative, weakly-developed soils on floodplains alternated with overbank alluviation and deposition on crevasse splay complexes on floodplains . Soil formation occurred on levees, point bars, crevasse splays and along the margins of floodplain lakes, ponds, and swamps. Soil-forming processes were interrupted by repeated deposition of sediment on top of soil profiles by flooding of nearby channels. Alluviation is evidenced by thin (fern and moss spores, projectates, age-diagnostic Wodehouseia edmontonicola, hinterland bisaccate pollen and pollen from lowland trees, shrubs, and herbs indicate an Early Maastrichtian age for these sediments. Large and small theropods, hadrosaurs, pachycephalosaurs, and ceratopsians, as well as fishes and fossil mammals have been found as well. Paleosols are similar to modern aquic subgroups of Entisols and Inceptisols and, in more distal locations, potential acid sulfate soils. Integration of pedogenic processes and palynology suggests that these high latitude floodplains were influenced by seasonally(?) fluctuating water table levels on a coastal plain governed by a near polar light

  16. Effect of coal ash disposal upon an unconfined alluvial system

    Energy Technology Data Exchange (ETDEWEB)

    Shergill, B.S.; Sendlein, L.V.A. (Univ. of Kentucky, Lexington, KY (United States). Dept. of Geological Sciences); Dinger, J.S. (Univ. of Kentucky, Lexington, KY (United States). Kentucky Geological Survey)

    1992-01-01

    Fly and bottom ash from coal combustion has been disposed in four ash ponds in an alluvial valley. Three of the ash ponds are receiving ash and one was filled and closed. Twenty eight monitoring wells ranging in depth from 10 feet to 65 feet have been installed at the site to study groundwater flow and chemistry. Hydraulic heads are influenced by the stage of the Kentucky River, and the flow direction is vertical below the ash ponds and predominantly horizontal a short distance from the pond all the way to the river. Three different groundwater flow zones were observed and have unique water chemistry. The deep zone (near bedrock) has a low Eh (< [minus]80), and high concentration of Fe, ammonia nitrogen, below detection sulfate values (< 5 mg/l) and trace metals. The age of the deep groundwater as determined by tritium analyses is between 20 to 30 years old (5.68 TU). The intermediate groundwater zone (from ash pond) has relatively higher Eh (> 100) and lower concentrations of Fe and ammonia nitrogen, median sulfate concentration (114 mg/l), and arsenic is below detection limits. The shallow groundwater zone is through the closed out ash point and has higher concentrations of nearly all cations and anions, including sulfate (888 mg/l) and arsenic (exists as arsenite) at concentration of 0.9 mg/l, low Eh (< [minus]100), and high pH. When shallow flow enters the alluvium, the sulfate are attenuated by sulfate reduction and this results in high bicarbonate values. Saturation indices (SI) as calculated by the geochemical model, MINTEQA2, indicate that deep and intermediate groundwater are unsaturated and shallow groundwater is at or near equilibrium with respect to calcite, dolomite, and gypsum.

  17. IBIEM modelling of the amplification of seismic waves by a three-dimensional layered alluvial basin

    Science.gov (United States)

    Liu, Zhongxian; Liang, Jianwen; Huang, Yihe; Liu, Lei

    2016-02-01

    We develop an indirect boundary integral equation method (IBIEM) to solve the scattering of seismic waves by a 3-D layered alluvial basin. We adopt the dynamic Green's functions for concentrated loads for a layered half-space derived from the modified stiffness method. This new algorithm of Green's function can solve the near-source response efficiently and accurately, and also facilitates the meshless implementation of the IBIEM. The numerical accuracy and stability of the IBIEM are tested for a homogeneous, hemispherical alluvial basin, and a two-layered model. Based on the IBIEM, the effects of several important parameters, such as the incident frequency, the angle of incidence and the properties of the alluvial layers are investigated for incident plane P and SV waves, respectively. The results show that the local amplification effects of a 3-D layered alluvial basin on the ground motion are strikingly significant, and that the spatial variation of the displacement response is drastic. We also find that the thickness of the near-surface low-velocity alluvial layer has a pronounced influence on the frequency spectrum of ground motion within the basin. As for the thick low-velocity layer, the amplification effect on the displacement amplitude spectrum appears in a wide range of frequencies, with more resonant models in the same frequency range. As for the thin low-velocity layer, in contrast, the amplification effect is close to the homogeneous case but becomes more significant for high-frequency waves. The displacement amplification for a basin with a soft intermediate layer is larger than that of the homogeneous basin for the lower frequencies, but seems to be weakened for high-frequency waves. Additionally, the damping ratio of the alluvial layer can substantially reduce the displacement amplitude in the basin, especially in the range of resonant frequencies. Our results provide a better understanding of the 3-D wave focusing and basin-edge effect within 3-D

  18. Localized sulfate-reducing zones in a coastal plain aquifer

    Science.gov (United States)

    Brown, C.J.; Coates, J.D.; Schoonen, M.A.A.

    1999-01-01

    High concentrations of dissolved iron in ground water of coastal plain or alluvial aquifers contribute to the biofouling of public supply wells for which treatment and remediation is costly. Many of these aquifers, however, contain zones in which microbial sulfate reduction and the associated precipitation of iron-sulfide minerals decreases iron mobility. The principal water-bearing aquifer (Magothy Aquifer of Cretaceous age) in Suffolk County, New York, contains localized sulfate-reducing zones in and near lignite deposits, which generally are associated with clay lenses. Microbial analyses of core samples amended with [14C]-acetate indicate that microbial sulfate reduction is the predominant terminal-electron-accepting process (TEAP) in poorly permeable, lignite-rich sediments at shallow depths and near the ground water divide. The sulfate-reducing zones are characterized by abundant lignite and iron-sulfide minerals, low concentrations of Fe(III) oxyhydroxides, and by proximity to clay lenses that contain pore water with relatively high concentrations of sulfate and dissolved organic carbon. The low permeability of these zones and, hence, the long residence time of ground water within them, permit the preservation and (or) allow the formation of iron-sulfide minerals, including pyrite and marcasite. Both sulfate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) are present beneath and beyond the shallow sulfate-reducing zones. A unique Fe(III)-reducing organism, MD-612, was found in core sediments from a depth of 187 m near the southern shore of Long Island. The distribution of poorly permeable, lignite-rich, sulfate-reducing zones with decreased iron concentration is varied within the principal aquifer and accounts for the observed distribution of dissolved sulfate, iron, and iron sulfides in the aquifer. Locating such zones for the placement of production wells would be difficult, however, because these zones are of limited aerial extent.

  19. Longitudinal Variation of River Hydrodynamics in a Semi-Alluvial River

    Science.gov (United States)

    Rennie, C. D.; Venditti, J. G.; Adderly, C.; Church, M. A.

    2012-12-01

    Knowledge of the longitudinal variation of river hydrodynamics is essential for understanding flood potential as well as transport of sediment, nutrients, and contaminants. The long profile has generally been studied by means of surveying a few representative cross-sections, along with cartographic analyses of the longitudinal variation of channel width and slope. Understanding the complete longitudinal distribution of river hydrodynamics generally requires numerical modelling. As an alternative, in this paper we present a 524 km continuous centreline acoustic Doppler current profiler (aDcp) survey of the dominantly rock-bound, gravel-bed Fraser River, British Columbia, Canada. Air photo analysis provided river widths along the surveyed reach, and the aDcp data yielded continuous centreline depth, depth-averaged velocity, and shear velocity. The survey reach was subdivided into 10 morphological sub-reaches, which ranged from alluvial gravel-bed reaches with relatively moderate slope to steep non-alluvial rock-walled canyons. Within each sub-reach the data were grouped based on presence of bedrock confinement on both banks, either bank, or neither bank. The results demonstrate that river widths decreased and water depths, flow velocities, and shear velocities increased from the alluvial sub-reaches to the semi-alluvial reaches to the canyon reaches. Within each sub-reach, locations with bedrock encroachment on both banks were narrower and deeper and had lower depth-averaged velocity and shear velocity. These results demonstrate the influence of bedrock on semi-alluvial channel morphology and hydrodyanamics.

  20. Alluvial systems as archives for environmental change at a Hominid site with Oldowan archaeological occurrences: the Homa Peninsula, southwestern Kenya

    Science.gov (United States)

    Vincent, Thomas; Whitfield, Elizabeth; Kirby, Jason; Hunt, Christopher; Bishop, Laura; Plummer, Thomas; Ditchfield, Peter

    2016-04-01

    The Homa Peninsula, southwestern Kenya, preserves fossiliferous sedimentary sequences dating to the Plio-Pleistocene. Evidence of hominids inhabiting an open grassland setting and utilising Oldowan tools has been reported here, as well as some of the oldest known traces of hominin activity. Reconstructions of the palaeoenvironment have suggested that alluvial and lake marginal environments on a grassy plain, between wooded slopes and a permanent water body might be plausible. However, these interpretations are based only on field sedimentological analyses and stable isotope analysis at a single site on the peninsula (Kanjera South). It is the aim of this study to utilise a multiproxy approach to develop our understanding of the palaeoenvironmental characteristics here. Sediments will also be characterized at a new site (Nyayanga) through field analyses, as well as through analyses of particle size, siliceous microfossils (diatoms, phytoliths and sponge spicules), pollen and stable isotopes. By utilizing this approach, new insights into the palaeoecology, palaeohydromorphology and palaeoclimate of the locale may be revealed, expanding the limited data available to palaeoanthropological studies of Oldowan occurrences in east Africa. Efforts to refine palaeoenvironmental reconstructions of Kanjera South through particle size analysis have shown that sediments in the lower beds of the sequence are characterised by poor sorting, a bimodal distribution and sand/silty-sand grade material. This suggests rapid deposition and/or a variable hydrological regime and may represent the role of relatively unconfined ephemeral channels in the transportation and deposition of sediments. Fluvial reworking of aeolian sediments, most likely during unconfined flood events may also have occurred.

  1. Event scale variability of mixed alluvial-bedrock channel dynamics

    Science.gov (United States)

    Cook, Kristen; Turowski, Jens; Hovius, Niels

    2015-04-01

    The relationship between flood events and fluvial behavior is critical for understanding how rivers may respond to the changing hydrologic forcing that may accompany climate change. In mixed bedrock-alluvial rivers, the response of the system to a flood event can be affected by a large number of factors, including coarse sediment availability in the channel, sediment supply from the hillslopes, bedrock-controlled changes in channel width and planform, and the shape of the hydrograph. We use the Daan River Gorge in western Taiwan as a case study to directly observe the effect of individual flood events on channel evolution. The 1200 m long and up to 20 m deep bedrock gorge formed in response to uplift of the riverbed during the 1999 Chi-Chi earthquake. The extremely rapid pace of change ensures that flood events have measurable and often dramatic effects on the channel. Taiwan is subject to both summer typhoons and a spring monsoon, resulting in numerous channel-altering floods with a range of magnitudes. Discharge is therefore highly variable, ranging from 5 to over 2000 m3/s, and changes in the channel are almost entirely driven by discrete flood events. Since early 2009 we have monitored changes in the gorge with repeated RTK GPS surveys, laser rangefinder measurements, and terrestrial LIDAR surveys. Six rainfall stations and five water level gauges provide hydrological data for the basin. We find a distinct relationship between flood magnitude and the magnitude of geomorphic change; however, we do not find a clear relationship between flood characteristics and the direction of change - whether the channel experienced aggradation or erosion in a particular flood. Upstream coarse sediment supply and the influence of abrupt changes in channel width on bedload flux through the gorge appear to have important influences on the channel response. The better understand these controls, we use the model sedFlow (Heimann et al., 2014) to explore the effects of interactions

  2. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-01-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  3. Planetary plains: subsidence and warping

    Science.gov (United States)

    Kochemasov, G.

    fabric of oceanic floors. Short, medium wave undulations of Pacific's floor (A. Cazenave et al., 1992; D. McAdoo & K. Marks, 1992) present lineations underlining its whole shape. NE lineations predominate on its northern sub-basin, NW lineations on its southern one. They cross at the equatorial zone and together with some other directions give a pattern resembling that observed on the venusian surface. The venusian regional plains typically deformed by wrinkle ridges show interesting similarities to volcanic plains on the Moon and Mars [3]. A subsidence along with warpings can squeeze out some "superfluous" material to surface through planetary scale fissures. This material builds mid-oceanic ridges and huge Hawaii volcano. The Cassini Regio on Iapetus is crossed in the equatorial plain by the dark ridge in some places high 20 km. References: [1] Kochemasov G. G. (2004) Mars and Earth: two dichotomies - one cause. In Workshop on "Hemispheres 1 apart: the origin and modification of the martian crustal dichotomy", LPI Contribution # 1203, Lunar and Planetary Institute, Houston, p. 37. [2] Kochemasov G.G.(1999) Theorems of wave planetary tectonics // Geophys. Res. Abstr. v.1, #3, p.700 . [3] Basilevsky A.T., Head J.W. (2006) Impact craters on regional plains in Venus: Age relations with wrinkle ridges and implications for the geological evolution of Venus // JGR, v.111, EO3006, doi: 10.1029/2005JE002473, 2006. 2

  4. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2004-10-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) by providing information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. Task 5 focused on screening and qualitatively assessing sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  5. Mangshan loess on China’s Central Plain and its response to tectonic movement and climate

    Institute of Scientific and Technical Information of China (English)

    吴锡浩; 蒋复初; 肖华国; 薛滨; 孙东怀

    1999-01-01

    The Mangshan loess on China’s Central Plain, located on the transitional zone between the uplifting Loess Plateau and the subsiding North China Plain, is a proximal sandy loess transported from the fanhead of alluvial fan in the lower reaches of the Yellow River and has recorded the eoupting effect of the tectonics and climate over the last 200 ka. An abrupt environmental change indicated by the abrupt rise of deposit rate in the late penultimate glaciation, about 150 ka BP, took place; that is, the Yellow River downcut and moved eastwards through the Sanmenxia Gorge and transported abundant materials from the Loess Plateau to form paleosol S1 with a thickness of 15.7 m and loess L1 with a thickness of 77.3 m. The loess-paleosol sequence at Mangshan has not only recorded detailed climate responses of this area to the East Asian monsoon, but also refleets the tectonogenetie environmental effect caused by the trunk stream of the Yellow River cutting through Sanmenxia Gorge into sea.

  6. Braidplain, floodplain and playa lake, alluvial-fan, aeolian and palaeosol facies composing a diversified lithogenetical sequence in the permian and triassic of South Devon (England)

    Science.gov (United States)

    Mader, Detlef

    The Permian and Triassic of South Devon (England) are a continental red bed sequence of very diversified lithogenetical composition. Within the thick series, the distribution of the main depositional environments being fluvial braidplain, fluvial floodplain and playa lake, alluvial fan, aeolian dune and calcrete palaeosol changes repeatedly in both horizontal and vertical direction. Significant sedimentary milieus such as aeolian dunes and calcrete palaeosols occur repeatedly within the succession, but are also lacking in several parts of the sequence. Fluvial braidplain deposits comprise conglomerates, sandstones, intraformational reworking horizons and mudstones and originate in channels and overbank plains of a braided river system. Conglomerates and sandstones are formed by migration of bars and spreading out of sheets during infilling of streams and aggradation of flats. Gravel is often enriched as lag pockets or veneers within steeper scour holes and kolk pots or on the plane floor of the watercourse. Finer-grained sandstones and mudstones are laid down by suspension settling in stagnant water bodies such as small lakes in the overbank area and residual pools in interbar depressions during low-stage or waning-flow in active channels or in abandoned streams. Spectacular bioturbation features in some sandstones with both horizontal tubes and vertical burrows testify to the colonization of the sediments at the bottom of the rivers with declining discharge and transport capacity. Intraformational reworking horizons with ghost-like remnants of degraded sandstones, mudstones and pedogenic carbonates document partially severe condensation of the sequence by removal of some facies elements from the depositional record. The occasionally occurring gravel-bearing mudstones or silty-clayey sandstones represent products of high-energy water surges overspilling the channel banks and transporting sandy and gravelly bed-load in limited amounts beyond the levee wall. The

  7. Morphometry and Geomorphic Characteristics of Large Alluvial fans and Megafans in South America

    Science.gov (United States)

    Latrubesse, E. M.; Sounny-Slitine, M. A.

    2015-12-01

    Alluvial megafans are 'large' fan-shaped bodies of sediment that form from lateral migrations of a river as it exits a topographic front. They differ from large alluvial fans (radial length between 30-100km) with sizes greater than 100-km in radial length. This study characterizes and describes megafans and large alluvial fan through morphometrics. We cataloged the fans into a geodatabase delineating size and extent of basins both upstream and downstream from the apex. Through remote sensing, elevation modeling and geomorphic mapping, we populated the database with fan morphometric measurements, qualitative descriptions and basin parameters. Metrics include planform area, catchment area, gradient, relief index, drainage density, and others. These were compared to longitudinal/transverse profiles, satellite imagery, and geomorphic maps. The database is global, however since the largest megafans of the world are located in South America, this preliminary analysis will focus on the continent. We found morphometric and characteristic differences between large alluvial fans and megafans in the region. These include difference in relationship between morphometrics, for example the ratio between catchment and fan size area. These properties of fans could be a better approach in differentiating megafans from large alluvial fans. The current criteria is an artificial scale divide, which varies in the literature, with the most common being a 100-km apex-to-toe length. Alternative values as little of 30-km apex-to-toe length have been proposed, as well as alternative metrics like coverage areas of greater than 10,000 square-km. We propose that geomorphic characteristics and morphometrics provide an intrinsic approach to differentiating megafans from larger alluvial fans.

  8. Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps

    Directory of Open Access Journals (Sweden)

    L. Marchi

    2010-03-01

    Full Text Available Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy. Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface.

  9. Occurrence of volcanic ash in the Quaternary alluvial deposits, lower Narmada basin, western India

    Indian Academy of Sciences (India)

    Rachna Raj

    2008-02-01

    This communication reports the occurrence of an ash layer intercalated within the late Quaternary alluvial succession of the Madhumati River, a tributary of the lower Narmada River. Petrographic, morphological and chemical details of glass shards and pumice fragments have formed the basis of this study. The ash has been correlated with the Youngest Toba Tuff. The finding of ash layer interbedded in Quaternary alluvial sequences of western Indian continental margin is significant, as ash being datable material, a near precise time-controlled stratigraphy can be interpreted for the Quaternary sediments of western India. The distant volcanic source of this ash requires a fresh re-assessment of ash volume and palaeoclimatic interpretations.

  10. Nest survival of forest birds in the Mississippi Alluvial Valley

    Science.gov (United States)

    Twedt, D.J.; Wilson, R.R.; Henne-Kerr, J.L.; Hamilton, R.B.

    2001-01-01

    In the Mississippi Alluvial Valley, flood control has led to a drastic reduction in the area of forest habitat and altered the patchwork of forest cover types. Silvicultural management of the remaining fragmented forests has changed to reflect the altered hydrology of the forests, current economic conditions of the area, and demand for forest products. Because forest type and silvicultural management impact forest birds, differences in avian productivity within these forests directly impact bird conservation. To assist in conservation planning, we evaluated daily nest survival, nest predation rates, and brood parasitism rates of forest birds in relation to different forest cover types and silvicultural management strategies within this floodplain. Within bottomland hardwood forests, nest success of blue-gray gnatcatcher (Polioptila caerulea, 13%), eastern towhee (Pipilo erythrophthalmus, 28%), indigo bunting (Passerina cyanea, 18%), northern cardinal (Cardinalis cardinalis, 22%), and yellow-billed cuckoo (Coccyzus americanus, 18%) did not differ from that within intensively managed cottonwood plantations. However, average daily survival of 542 open-cup nests of 19 bird species in bottomland hardwoods (0.9516 + 0.0028, -27% nest success) was greater than that of 543 nests of 18 species in cotlonwood plantations (0.9298 + 0.0035, -15% nest success). Differences in daily nest survival rates likely resulted from a combination of differences in the predator community--particularly fire ants (Solenopsis invicta)--and a marked difference in species composition of birds breeding within these 2 forest types. At least 39% of nests in bottomland hardwood forests and 65% of nests in cottonwood plantations were depredated. Rates of parasitism by brown-headed cowbirds (Molothrus ater) were greater in managed cottonwoods (24%) than in bottomland hardwoods (9%). Nest success in planted cottonwood plantations for 18 species combined (-14%), and for yellow-breasted chat (Icteria

  11. Alluvial deposits and plant distribution in an Amazonian lowland megafan

    Science.gov (United States)

    Zani, H.; Rossetti, D.; Cremon; Cohen, M.; Pessenda, L. C.

    2012-12-01

    A large volume of sandy alluvial deposits (> 1000 km2) characterizes a flat wetland in northern Amazonia. These have been recently described as the sedimentary record of a megafan system, which have a distinct triangular shape produced by highly migratory distributary rivers. The vegetation map suggests that this megafan is dominated by open vegetation in sharp contact with the surround rainforest. Understanding the relationship between geomorphological processes and vegetation distribution is crucial to decipher and conserve the biodiversity in this Amazonian ecosystem. In this study we interpret plant dynamics over time, and investigate its potential control by sedimentary processes during landscape evolution. The study area is located in the Viruá National Park. Two field campaigns were undertaken in the dry seasons of 2010 and 2011 and the sampling sites were selected by combining accessibility and representativeness. Vegetation contrasts were recorded along a transect in the medial section of the Viruá megafan. Due to the absence of outcrops, samples were extracted using a core device, which allowed sampling up to a depth of 7.5 m. All cores were opened and described in the field, with 5 cm3 samples collected at 20 cm intervals. The δ13C of organic matter was used as a proxy to distinguish between C3 and C4 plant communities. The chronology was established based on radiocarbon dating. The results suggest that the cores from forested areas show the most depleted values of δ13C, ranging from -32.16 to -27.28‰. The δ13C curve in these areas displays typical C3 land plant values for the entire record, which covers most of the Holocene. This finding indicates that either the vegetation remained stable over time or the sites were dominated by aquatic environments with freshwater plants before forest establishment. The cores from the open vegetation areas show a progressive upward enrichment in δ13C values, which range from -28.50 to -19.59‰. This trend is

  12. Whillans Ice Plain Stick Slip

    Science.gov (United States)

    Lipovsky, B.; Dunham, E. M.

    2015-12-01

    Concern about future sea level rise motivates the study of fast flowing ice. The Whillans Ice Plain (WIP) region of the West Antarctic Ice Sheet is notable for decelerating from previously fast motion during the instrumental record. Since most ice flux in Antarctica occurs through ice streams, understanding the conditions that cause ice stream stagnation is of basic importance in understanding the continent's contribution to future sea level rise. Although recent progress has been made in understanding the relationship between basal conditions and ice stream motion, direct observation of the temporal variation in subglacial conditions during ice stream stagnation has remained elusive. The Whillans Ice Plain flows to the sea mostly by way of stick-slip motion. We present numerical simulations of this stick-slip motion that capture the inertial dynamics, seismic waves, and the evolution of sliding with rate- and state-dependent basal friction. Large scale stick-slip behavior is tidally modulated and encompasses the entire WIP. Sliding initiates within one of several locked regions and then propagates outward with low average rupture velocity (~ 200 m/s). Sliding accelerates over a period of 200 s attain values as large as 65 m/d. From Newton's second law, this acceleration is ~ T / (rho H) for average shear stress drop T, ice thickness H, and ice density rho. This implies a 3 Pa stress drop that must be reconciled with the final stress drop of 300 Pa inferred from the total slip and fault dimensions. A possible explanation of this apparent discrepancy is that deceleration of the ice is associated with a substantial decrease in traction within rate-strengthening regions of the bed. During these large-scale sliding events, m-scale patches at the bed produce rapid (20 Hz) stick-slip motion. Each small event occurs over ~ 1/100 s, produces ~ 40 microns of slip, and gives rise to a spectacular form of seismic tremor. Variation between successive tremor episodes allows us

  13. 7 CFR 650.25 - Flood-plain management.

    Science.gov (United States)

    2010-01-01

    ... flood plain. Department of Housing and Urban Development (HUD) flood insurance maps, other available... 7 Agriculture 6 2010-01-01 2010-01-01 false Flood-plain management. 650.25 Section 650.25... Flood-plain management. Through proper planning, flood plains can be managed to reduce the threat...

  14. 44 CFR 10.14 - Flood plains and wetlands.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood plains and wetlands. 10... Flood plains and wetlands. For any action taken by FEMA in a flood plain or wetland, the provisions of... Executive Order 11988, Flood Plain Management, and Executive Order 11990, Protection of Wetlands (44...

  15. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Thea E. Reikoff

    2005-04-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership continues to make great progress. Task 2 (Technology Deployment) focused on developing information regarding deployment issues to support Task 5 (Modeling and Phase II Action Plans) and provided information to be used to assess CO{sub 2} sequestration opportunities in the PCOR Partnership region. Task 2 efforts also included preparation of a draft topical report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region'', which is nearing completion. Task 3 (Public Outreach) focused on developing an informational video about CO{sub 2} sequestration. The video will be completed and aired on Prairie Public Television in the next quarter. Progress in Task 4 (Sources, Sinks, and Infrastructure) included the continued collection of data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation. The addition of the Canadian province of Alberta to the PCOR Partnership region expanded the decision support system (DSS) geographic information system database. Task 5 screened and qualitatively assessed sequestration options. Task 5 activities also continue to be useful in structuring data collection and other activities in Tasks 2, 3, and 5.

  16. PLAINS CO2 REDUCTION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; John A. Harju; Erin M. O' Leary; James A. Sorensen; Daniel J. Daly; Melanie D. Jensen; Lisa S. Botnen

    2005-07-01

    The Plains CO{sub 2} Reduction (PCOR) Partnership characterization work is nearing completion, and most remaining efforts are related to finalizing work products. Task 2 (Technology Deployment) has developed a Topical Report entitled ''Deployment Issues Related to Geologic CO{sub 2} Sequestration in the PCOR Partnership Region''. Task 3 (Public Outreach) has developed an informational Public Television program entitled ''Nature in the Balance'', about CO{sub 2} sequestration. The program was completed and aired on Prairie Public Television in this quarter. Task 4 (Sources, Sinks, and Infrastructure) efforts are nearing completion, and data regarding CO{sub 2} sources and sinks and data on the performance and costs for CO{sub 2} separation, capture, treatment, and compression for pipeline transportation are being incorporated into a series of topical reports. The expansion of the Decision Support System Geographic Information System database has continued with the development of a ''save bookmark'' feature that allows users to save a map from the system easily. A feature that allows users to develop a report that summarizes CO{sub 2} sequestration parameters was also developed. Task 5 (Modeling and Phase II Action Plans) focused on screening and qualitatively assessing sequestration options and developing economic estimates for important regional CO{sub 2} sequestration strategies.

  17. Geo-archaeological aspects of the Modena plain (Northern Italy

    Directory of Open Access Journals (Sweden)

    Doriano Castaldini

    2007-12-01

    Full Text Available This paper traces the various stages of geomorphological evolution of the plain area around Modena from the VIth millennium B.C.E. (Neolithic to the Present, through a reconstruction of the ancient landscape and human settlements.By means of a GIS platform, geomorphological investigations led to the implementation of a Microrelief Map, a Digital Elevation Model (DEM, a Map of Surface Deposits and a Geomorphological Map.The most striking altimetric features in the study area are the morphological changes of the Rivers Secchia and Panaro: south of Modena they run deep in the alluvial plain whereas north of the town they flow elevated over the plain. The surface lithology consists mainly of silt, with bands of sand and clay; mainly gravel deposits crop out only near southern tracks of the main Apennine watercourses. The geomorphological landscape is mainly characterised by alluvial fans, fluvial ridges paleo-riverbeds fluvial scarps, natural springs and some depressed areas; worth of note are also forms connected with human activity.There have been several attempts to cross–date geological and geomorphological evidence with archaeological data, on both detailed and wide territorial scales. A further advancement can now be attempted by comparing data obtained from systematic research on fluvial forms with data contained in the archives.In the area studied, some 800 archaeological sites were identified and catalogued. Such a high number of archaeological sites can give a great deal more information than is found in any other place in northern Italy.The research took into account the overlapping of archaeological and geomorphological data, with the implementation into a GIS (ArcGis 8.3 of geoarchaeological maps divided in main periods and here represented from the Neolithic to the to Iron Age and from Roman period to the Early Middle Ages. The dating thus obtained for fluvial forms was mainly based on the relationship between these forms and

  18. 75 FR 62137 - Notice of Public Meeting; Proposed Alluvial Valley Floor Coal Exchange Public Interest Factors...

    Science.gov (United States)

    2010-10-07

    ... written testimony and comments on the public interest factors (see determination of public interest at 43... final decision on the proposed exchange and whether it is in the public interest. The BLM will discuss... Bureau of Land Management Notice of Public Meeting; Proposed Alluvial Valley Floor Coal Exchange...

  19. Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels

    NARCIS (Netherlands)

    Crosato, A.; Mosselman, E.; Desta, F.B.; Uijttewaal, W.S.J.

    2011-01-01

    Alternate bars in straight alluvial channels are migrating or nonmigrating. The currently accepted view is that they are nonmigrating if the width-to-depth ratio is at the value of resonance or if the bars are forced by a persistent local perturbation. We carried out 2-D numerical computations and a

  20. Intrinsic steady alternate bars in alluvial channels. Part 1: experimental observations and numerical tests.

    NARCIS (Netherlands)

    Crosato, A.; Desta, F.B.

    2009-01-01

    Alternate bars in straight alluvial channels are migrating or steady. The currently accepted view is that they are steady only if the width-to-depth ratio is at the value of resonance or if the bars are forced by a steady local perturbation. Experimental observations, however, seem to indicate that

  1. The alluvial architecture of the Coevorden Field (Upper Carboniferous), the Netherlands

    NARCIS (Netherlands)

    Kombrink, H.; Bridge, J.S.; Stouthamer, E.

    2007-01-01

    A detailed reconstruction of the alluvial architecture of the Coevorden gas Field (Tubbergen Formation, Upper Carboniferous), which is located in the northeastern part of the Netherlands, is presented. This reconstruction is based on well logs, cross-sections and paleogeographic maps. Sedimentolog

  2. Debris-flow dominance of alluvial fans masked by runoff reworking and weathering

    NARCIS (Netherlands)

    de Haas, Tjalling; Ventra, Dario; Carbonneau, Patrice E.; Kleinhans, Maarten G.

    2014-01-01

    Arid alluvial fan aggradation is highly episodic and fans often comprise active and inactive sectors. Hence the morphology and texture of fan surfaces are partly determined by secondary processes of weathering and erosion in addition to primary processes of aggradation. This introduces considerable

  3. Potential water supply of a small reservoir and alluvial aquifer system in southern Zimbabwe

    NARCIS (Netherlands)

    Hamer, de W.; Love, D.; Owen, R.; Booij, M.J.; Hoekstra, A.Y.

    2007-01-01

    Groundwater use by accessing alluvial aquifers of non‐perennial rivers can be an important additional water resource in the semi‐arid region of southern Zimbabwe. The research objective of the study was to calculate the potential water supply for the upper‐Mnyabezi catchment under current conditions

  4. Potential water supply of a small reservoir and alluvial aquifer system in southern Zimbabwe

    NARCIS (Netherlands)

    Hamer, de W.; Love, D.; Owen, R.; Booij, M.J.; Hoekstra, A.Y.

    2008-01-01

    Groundwater use by accessing alluvial aquifers of non-perennial rivers can be an important additional water resource in the semi-arid region of southern Zimbabwe. The research objective of the study was to calculate the potential water supply for the upper-Mnyabezi catchment under current conditions

  5. Floodplain morphology, sedimentology, and development processes of a partially alluvial channel

    Science.gov (United States)

    Thayer, James B.; Ashmore, Peter

    2016-09-01

    The floodplain morphology, sediment deposits, and development mechanisms of a partially alluvial, low-moderate energy channel flowing over a mixed gravel/cobble-till bed are investigated and compared to existing ideas of floodplain development. The findings partially support the idea of a floodplain developed through lateral accretion capped with vertically accreted sediments as predicted by the energy-based classification scheme of Nanson and Croke (1992), though oblique accretion and partial channel avulsion are also important. Channel migration consists of limited cross-valley migration and downstream meander translation. Because of low channel sinuosity, well-formed neck cutoffs are rare, and instead the channel cuts headward along the insides of confined or underdeveloped meander bends forming a localized anabranching pattern. The floodplain architecture can be divided into gravel bar and bed deposits (GB), lateral accretion deposits (LA), overbank deposits (FF), and abandoned channel deposits (FF(CH)), which are described with four alluvial facies. Owing to the limited supply of coarse and fine sediment, none of the architectural elements are particularly thick, with total floodplain thickness being < 3 m. Floodplain development for partially alluvial channels is compared within a new floodplain discrimination framework. Comparisons with common facies models of single-thread, coarse-grained channels show important differences that suggest that the floodplain deposits and formative processes described herein represent a subset of single-thread systems that may be common in partially alluvial channels, particularly in slightly sinuous, coarse-grained channels of low-moderate energy with partly confined floodplains.

  6. The recharge process in alluvial strip aquifers in arid Namibia and implication for artificial recharge

    Science.gov (United States)

    Sarma, Diganta; Xu, Yongxin

    2016-10-01

    Alluvial strip aquifers associated with ephemeral rivers are important groundwater supply sources that sustain numerous settlements and ecological systems in arid Namibia. More than 70 % of the population in the nation's western and southern regions depend on alluvial aquifers associated with ephemeral rivers. Under natural conditions, recharge occurs through infiltration during flood events. Due to the characteristic spatial and temporal variability of rainfall in arid regions, recharge is irregular making the aquifers challenging to manage sustainably and they are often overexploited. This condition is likely to become more acute with increasing water demand and climate change, and artificial recharge has been projected as the apparent means of increasing reliability of supply. The article explores, through a case study and numerical simulation, the processes controlling infiltration, significance of surface water and groundwater losses, and possible artificial recharge options. It is concluded that recharge processes in arid alluvial aquifers differ significantly from those processes in subhumid systems and viability of artificial recharge requires assessment through an understanding of the natural recharge process and losses from the aquifer. It is also established that in arid-region catchments, infiltration through the streambed occurs at rates dependent on factors such as antecedent conditions, flow rate, flow duration, channel morphology, and sediment texture and composition. The study provides an important reference for sustainable management of alluvial aquifer systems in similar regions.

  7. Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation

    Directory of Open Access Journals (Sweden)

    P. Négrel

    2004-01-01

    Full Text Available This study presents strontium isotope and major ion data of shallow groundwater and river water from the Ile du Chambon catchment, located on the Allier river in the Massif Central (France. There are large variations in the major-element contents in the surface- and groundwater. Plotting of Na vs. Cl contents and Ca, Mg, NO3, K, SO4, HCO3, Sr concentrations reflect water–rock interaction (carbonate dissolution for Ca, Mg, HCO3 and Sr because the bedrock contains marly limestones, agricultural input (farming and fertilising and sewage effluents (for NO3, K, SO4, although some water samples are unpolluted. Sr contents and isotope ratios (87Sr/86Sr vary from 0.70892 to 0.71180 along the hydrological cycle in the groundwater agree with previous work on groundwater in alluvial aquifers in the Loire catchment. The data plot along three directions in a 87Sr/86Sr v. 1/Sr diagram as a result of mixing, involving at least three geochemical signatures–Allier river water, and two distinct signatures that might be related to different water-rock interactions in the catchment. Mixing proportions are calculated and discussed. The alluvial aquifer of the Ile du Chambon catchment is considered, within the Sr isotope systematic, in a larger scheme that includes several alluvial aquifers of the Loire Allier catchment. Keywords: : Loire river, major and trace elements, Sr isotopic ratio, alluvial aquifer, hydrology

  8. Clogging of water supply wells in alluvial aquifers by mineral incrustations, central Serbia

    Directory of Open Access Journals (Sweden)

    Majkić-Dursun Brankica

    2015-01-01

    Full Text Available The formation of incrustations on public water supply well screens reduces their performance considerably. The incrustations increase hydraulic losses, reduce the capacity of the well and screen, affect the quality of the pumped water and increase maintenance costs. In alluvial environments, the most common deposits are iron and manganese hydroxides. However, the rates of formation, compositions and levels of crystallization vary, depending on the geochemical characteristics of the alluvial environment, the microbiological characteristics of the groundwater and the abstraction method. Samples of 15 incrustations were collected from wells that tap shallow alluvial aquifers and were found to be dominated by iron. XRD analyses detected low-crystalline ferrihydrite and manganese hydroxide in the samples collected from the water supply source at Trnovče (Velika Morava alluvial. The incrustations from the Belgrade Groundwater Source revealed the presence of ferrihydrite and a substantial amount of goethite α-FeOOH. Apart from goethite, greigite (Fe3S4 was detected in three samples, while one sample additionally contained bernalite Fe(OH3 and monoclinic sulfur S8. Among carbonates, only siderite was detected. Iron oxidizing bacteria generally catalyze deposition processes in wells, while sulfate reducing bacteria (SRB play a role in the biogenic formation of greigite. Determining the nature of the deposited material allows better selection of rehabilitation chemicals and procedure. [Projekat Ministarstva nauke Republike Srbije, br. TR37014

  9. Late Pleistocene-Holocene alluvial stratigraphy of southern Baja California, Mexico

    Science.gov (United States)

    Antinao, José Luis; McDonald, Eric; Rhodes, Edward J.; Brown, Nathan; Barrera, Wendy; Gosse, John C.; Zimmermann, Susan

    2016-08-01

    A late Pleistocene to Holocene alluvial stratigraphy has been established for the basins of La Paz and San José del Cabo, in the southern tip of the Baja California peninsula, Mexico. Six discrete alluvial units (Qt1 through Qt6) were differentiated across the region using a combination of geomorphologic mapping, sedimentological analysis, and soil development. These criteria were supported using radiocarbon, optically stimulated luminescence and cosmogenic depth-profile geochronology. Major aggradation started shortly after ∼70 ka (Qt2), and buildup of the main depositional units ended at ∼10 ka (Qt4). After deposition of Qt4, increasing regional incision of older units and the progressive development of a channelized alluvial landscape coincide with deposition of Qt5 and Qt6 units in a second, incisional phase. All units consist of multiple 1-3 m thick alluvial packages deposited as upper-flow stage beds that represent individual storms. Main aggradational units (Qt2-Qt4) occurred across broad (>2 km) channels in the form of sheetflood deposition while incisional stage deposits are confined to channels of ∼0.5-2 km width. Continuous deposition inside the thicker (>10 m) pre-Qt5 units is demonstrated by closely spaced dates in vertical profiles. In a few places, disconformities between these major units are nevertheless evident and indicated by partly eroded buried soils. The described units feature sedimentological traits similar to historical deposits formed by large tropical cyclone events, but also include characteristics of upper-regime flow sedimentation not shown by historical sediments, like long (>10 m) wavelength antidunes and transverse ribs. We interpret the whole sequence as indicating discrete periods during the late Pleistocene and Holocene when climatic conditions allowed larger and more frequent tropical cyclone events than those observed historically. These discrete periods are associated with times when insolation at the tropics was

  10. Late Quaternary Alluvial Fans of Southern Baja California, Mexico: Relation to Eastern Pacific Tropical Cyclones

    Science.gov (United States)

    Antinao, J.; McDonald, E.

    2009-12-01

    In the arid, non-glaciated regions of the Southwestern USA and Northwestern Mexico, aggradation in alluvial fan systems has been traditionally linked to cold and humid periods (e.g., Last Glacial Maximum) or to the transition to warm periods (e.g., the Pleistocene-Holocene transition, PHT). However, major intervals of sediment transport and aggradation have also occurred during climatically warm periods in these regions. These periods have also been identified as portraying enhanced humidity or “monsoonal’ conditions. Investigations on the weather systems able to perform geomorphic work during predominantly warm periods, i.e. the North American Monsoon (NAM) and Eastern Pacific (EP) Tropical Cyclones (TCs), have concentrated mainly in the USA. To understand the relative contribution of these systems to sediment transport over millennial timescales, we have mapped and characterized preliminarily the alluvial fans in four different areas of the Southern Baja California peninsula, Mexico. This region is dominated by EPTC precipitation, which in turn is driving the sediment transport along alluvial channels. Detailed geomorphologic mapping shows that a distinct Late Quaternary chronostratigraphy of alluvial fan units can be developed using geochronological and pedological tools. Specifically, a soil chronosequence can be compared to sequences in the SW USA, allowing a correlation to Late Pleistocene - Holocene events in the region. At least five alluvial units can be identified. Older units have well defined gravel pediments, Av and B horizons and pervasive pedogenic carbonate morphology, with alluvial terraces that rise tens of meters above the present channel. Intermediate age units have developed B horizons and carbonate morphology at different stages. The younger units have thin soil horizons, no carbonate morphology in the soil profile, and some of them are subject to episodic flooding during TC activity. The chronosequence developed is the first step towards

  11. Surface exposure dating of moraines and alluvial fans in the Southern Central Andes

    Science.gov (United States)

    Terrizzano, Carla; Zech, Roland; García Morabito, Ezequiel; Haghipour, Negar; Christl, Marcus; Likermann, Jeremías; Tobal, Jonathan; Yamin, Marcela

    2016-04-01

    The role of tectonics versus climate in controlling the evolution of alluvial fans in discussed controversially. The southern Central Andes and their forelands provide a perfect setting to study climate versus tectonic control of alluvial fans. On the one hand, the region is tectonically active and alluvial fan surfaces are offset by faults. The higher summits, on the other hand, are glaciated today, and glacial deposits document past periods of lower temperatures and increased precipitation. We applied 10Be surface exposure dating on 5 fan terraces 4 moraines of the Ansilta range (31.6°S - 69.8°W) using boulders and amalgamated pebbles to explore their chronological relationship. From youngest to oldest, the alluvial fan terraces yield minimum ages of 15 ± 1 ka (T1), 97 ± 9 ka (T2), 141 ± 9 ka (T3), 286 ± 14 ka (T4) and 570 ± 57 ka (T5). Minimum ages derived from moraines are 14 ± 1 ka (M1), 22 ± 2 ka (M2), 157 ± 14 ka (M3) and 351 ± 33 ka (M4), all calculations assuming no erosion and using the scaling scheme for spallation based on Lal 1991, Stone 2000. The moraines document glacial advances during cold periods at the marine isotope stages (MIS) 2, 6 and 10. The terraces T1, T3 seem to be geomorphologic counterparts during MIS 2 and 6. We suggest that T2, T4 and T5 document aggradation during the cold periods MIS 5d, 8 and 14 in response to glacial advances, although the respective moraines are not preserved. Our results highlight: i) the arid climate in the Southern Central Andes favors the preservation of glacial and alluvial deposits allowing landscape and climate reconstructions back to ~570 ka), ii) alluvial deposits correlate with moraines or fall into cold glacial times, so that climate, and in particular the existence of glaciers, seems to be the main forcing of alluvial fan formation at our study site. References Lal, D., 1991: Cosmic ray labeling of erosion surfaces: In situ nuclide production rates and erosion models. Earth and Planetary

  12. Exploring the use of weathering indexes in an alluvial fan chronology

    Science.gov (United States)

    Hardenbicker, Ulrike; Watanabe, Makiko; Kotowich, Roberta

    2015-04-01

    Alluvial fan sediments can act as an archive of local environmental history. Two borehole cores (FN 350 cm and AG 850cm) from Holocene alluvial fans located in the Qu'Appelle Valley in southern Saskatchewan were analyzed in order to identify how changes in land use of upland catchment plateaus modified the pattern and rate of sediment delivery to the fan. Due to the lack of material for radiometric dating a chronology of depositional events within the alluvial fans was established by using lithostratigraphy data of soils and sediments. In order to establish a more detailed relative chronology we evaluated if weathering indexes (the Parker Index, the CaO/ZrO2 molar ratio, the Product Index) originally developed for studies of in situ weathering of bedrock, are suitable to assess sediment weathering within alluvial fan sediments. To quantify the degree of weathering within the sediment samples the three indexes of weathering were calculated using the proportions of elements measure by Energy Dispersive X-ray Spectroscopy and there is an inverse relationship between weathering index and sample age. For further statistical analyses the fan sediments were classified into three groups: a sheet flow facies of well sorted silt loam and sandy loam textures, bed load facies characterized by high sand and gravel content and layers with high organic matter in combination with higher clay content indicative of in situ weathering and soil development. First results show that the Product Index may be the most suitable weathering index to indicate weathering or input of less weathered sediment within the sheet flow and bed load facies. In general, the weathering indexes do not take into account complexities of the weathering processes nor the overall environmental conditions in an alluvial fan. But chemical weathering indexes accompanied by geophysical and geo-chemical information have value, especially when the amount of sample material is limited.

  13. Application of flood index in monitoring Flood-plain ecosystems (by the example of the Middle Ob flood-plain)

    OpenAIRE

    Bolotnov, V. P.

    2007-01-01

    The concept of regional hydroecological monitoring has been developed for the flood-plain of the Middle Ob. Its object is to control the state of flood-plain ecosystem productivity for organization of scientific, regional-adopted and ecologically regulated nature management. For this purpose hydroecological zoning of flood-plain territory performed, the most representative stations of water-gauge observations for each flood-plain zone organized, the scheme of flood-plain flooding was prepared...

  14. Characteristics and origin of Earth-mounds on the Eastern Snake River Plain, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.A.

    1995-09-01

    Earth-mounds are common features on the Eastern Snake River Plain, Idaho. The mounds are typically round or oval in plan view, <0.5 m in height, and from 8 to 14 m in diameter. They are found on flat and sloped surfaces, and appear less frequently in lowland areas. The mounds have formed on deposits of multiple sedimentary environments. Those studied included alluvial gravel terraces along the Big Lost River (late Pleistocene/early Holocene age), alluvial fan segments on the flanks of the Lost River Range (Bull Lake and Pinedale age equivalents), and loess/slopewash sediments overlying basalt flows. Backhoe trenches were dug to allow characterization of stratigraphy and soil development. Each mound has features unique to the depositional and pedogenic history of the site; however, there are common elements to all mounds that are linked to the history of mound formation. Each mound has a {open_quotes}floor{close_quotes} of a sediment or basement rock of significantly different hydraulic conductivity than the overlying sediment. These paleosurfaces are overlain by finer-grained sediments, typically loess or flood-overbank deposits. Mounds formed in environments where a sufficient thickness of fine-grained sediment held pore water in a system open to the migration to a freezing front. Heaving of the sediment occurred by the growth of ice lenses. Mound formation occurred at the end of the Late Pleistocene or early in the Holocene, and was followed by pedogenesis. Soils in the mounds were subsequently altered by bioturbation, buried by eolian deposition, and eroded by slopewash runoff. These secondary processes played a significant role in maintaining or increasing the mound/intermound relief.

  15. Geologically based model of heterogeneous hydraulic conductivity in an alluvial setting

    Science.gov (United States)

    Fogg, Graham E.; Noyes, Charles D.; Carle, Steven F.

    Information on sediment texture and spatial continuity are inherent to sedimentary depositional facies descriptions, which are therefore potentially good predictors of spatially varying hydraulic conductivity (K). Analysis of complex alluvial heterogeneity in Livermore Valley, California, USA, using relatively abundant core descriptions and field pumping-test data, demonstrates a depositional-facies approach to characterization of subsurface heterogeneity. Conventional textural classifications of the core show a poor correlation with K; however, further refinement of the textural classifications into channel, levee, debris-flow, and flood-plain depositional facies reveals a systematic framework for spatial modeling of K. This geologic framework shows that most of the system is composed of very low-K flood-plain materials, and that the K measurements predominantly represent the other, higher-K facies. Joint interpretation of both the K and geologic data shows that spatial distribution of K in this system could not be adequately modeled without geologic data and analysis. Furthermore, it appears that K should not be assumed to be log-normally distributed, except perhaps within each facies. Markov chain modeling of transition probability, representing spatial correlation within and among the facies, captures the relevant geologic features while highlighting a new approach for statistical characterization of hydrofacies spatial variability. The presence of fining-upward facies sequences, cross correlation between facies, as well as other geologic attributes captured by the Markov chains provoke questions about the suitability of conventional geostatistical approaches based on variograms or covariances for modeling geologic heterogeneity. Résumé Les informations sur la texture des sédiments et leur continuité spatiale font partie des descriptions de faciès sédimentaires de dépôt. Par conséquent, ces descriptions sont d'excellents prédicteurs potentiels des

  16. Evaluation of groundwater levels in the South Platte River alluvial aquifer, Colorado, 1953-2012, and design of initial well networks for monitoring groundwater levels

    Science.gov (United States)

    Wellman, Tristan

    2015-01-01

    The South Platte River and underlying alluvial aquifer form an important hydrologic resource in northeastern Colorado that provides water to population centers along the Front Range and to agricultural communities across the rural plains. Water is regulated based on seniority of water rights and delivered using a network of administration structures that includes ditches, reservoirs, wells, impacted river sections, and engineered recharge areas. A recent addendum to Colorado water law enacted during 2002-2003 curtailed pumping from thousands of wells that lacked authorized augmentation plans. The restrictions in pumping were hypothesized to increase water storage in the aquifer, causing groundwater to rise near the land surface at some locations. The U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board and the Colorado Water Institute, completed an assessment of 60 years (yr) of historical groundwater-level records collected from 1953 to 2012 from 1,669 wells. Relations of "high" groundwater levels, defined as depth to water from 0 to 10 feet (ft) below land surface, were compared to precipitation, river discharge, and 36 geographic and administrative attributes to identify natural and human controls in areas with shallow groundwater.

  17. Patterns and Processes of Width Adjustment to Increased Streamflows in Semi-Alluvial Rivers

    Science.gov (United States)

    Kelly, S. A.; Belmont, P.

    2015-12-01

    While it is understood that river channel width is determined by fluxes of water and sediment, predictive models of channel width, and especially changes in width under non-stationary conditions, have proven elusive. Classic hydraulic geometry relations commonly used in numerical models and channel design typically scale width as a power law function of discharge, without consideration of bank properties. This study investigates the role of bank material in determining spatial and temporal variability in channel width and widening rates for semi-alluvial rivers that have experienced increases in flow. The 45,000 km2 Minnesota River Basin contains many semi-alluvial rivers that have been rapidly incising into fine-grained glacial deposits over the last 13,400 years in response to a catastrophic base level drop. Large, recent increases in streamflows have caused significant channel widening and migration, exacerbated erosion of channel (alluvial) banks and (consolidated till) bluffs, and dramatically increased sediment supply. Here we leverage multiple decades of aerial photos, repeat lidar surveys, Structure from Motion photogrammetry and sediment gaging to examine past, and predict future, changes in channel width. We use empirical observations and a simple model to examine whether semi-alluvial channels tend toward a single, or multiple, equilibrium channel width(s). Preliminary results suggest that under stationary hydrologic conditions (1930s - 1970s) channel width was relatively consistent among reaches underlain by alluvium versus consolidated till. Since the late 1970s the study area has undergone profound hydrologic changes, with geomorphically-active flows nearly doubling in magnitude. Alluvial reaches widened relatively quickly in response to the increase in flows, whereas reaches underlain by till have not seen the same amount of widening. Aerial lidar-based geomorphic change detection between 2005 - 2012 records channel width changes in response to an

  18. Plain carbon steel bipolar plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    WANG Jianli; SUN Juncai; TIAN Rujin; XU Jing

    2006-01-01

    Bipolar plates are a multifunctional component of PEMFC. Comparing with the machined graphite and stainless steels, the plain carbon steel is a very cheap commercial metal material. In this paper, the possibility of applying the plain carbon steels in the bipolar plate for PEMFC was exploited. In order to improve the corrosion resistance of the low carbon steel in the PEMFCs' environments,two surface modification processes was developed and then the electrochemical performances and interfacial contact resistance (ICR) of the surface modified plate of plain carbon steel were investigated. The results show that the surface modified steel plates have good corrosion resistance and relatively low contact resistance, and it may be a candidate material as bipolar plate of PEMFC.

  19. Hydrogeochemical analysis for Tasuj plain aquifer, Iran

    Indian Academy of Sciences (India)

    Ata Allah Nadiri; Asghar Asghari Moghaddam; Frank T-C Tsai; Elham Fijani

    2013-08-01

    This study investigated the hydrogeochemical processes of groundwater in the Tasuj plain, Iran. The Tasuj plain is one of the 12 marginal plains around Urmia Lake which is currently under a critical ecological condition. In the last decades, the Tasuj plain aquifer suffered from severe groundwater level declination and caused degradation of groundwater quality. To better understand hydrogeochemical processes in the Tasuj plain, this study adopted graphical methods and multivariate statistical techniques to analyze groundwater samples. A total of 504 groundwater samples was obtained from 34 different locations (qanats, wells, and springs) over 12 years (1997–2009) and analyzed for 15 water quality parameters. From the results, the Piper diagram indicated four groundwater types and the Stiff diagram showed eight different sources of groundwater samples. The Durov diagram identified five major hydrogeochemical processes in the aquifer. However, hierarchical cluster analysis (HCA) identified five water types in the groundwater samples because HCA was able to analyze more chemical and physical data than graphical methods. The HCA result was checked by discriminant analysis and found consistency in all samples that were classified into correct groups. Using factor analysis, we identified three factors that accounted for 81.6% of the total variance of the dataset. Based on the high factor loadings of the variables, factors 1 and 2 reflected the natural hydrogeochemical processes and factor 3 explained the effect of agricultural fertilizers and human activities in the Tasuj plain. Dendrograms from 2000 to 2009 were studied to understand the temporal variation of groundwater quality. Comparing the distributions of groundwater types in 2000 and 2009, we found that the mixing zone was expanded. This may be due to artificial groundwater recharge in the recharge area and the effect of inverse ion exchange in the discharge area.

  20. Drought Assessment in the Moldavian Plain

    Directory of Open Access Journals (Sweden)

    Pelin Liviu Ioan

    2016-06-01

    Full Text Available The Moldavian Plain, located in the North-Eastern part of Romania, has a temperate-continental climate with a nuance of excessivity in the precipitation regime. This paper aims to analyse droughts in the Moldavian Plain for the period 1961-2010, by using a classical method - the de Martonne Aridity Index, and two other less known indices developed in Romania and the Republic of Moldova. Among these indices, the Dry Spells Index demonstrates a increasing frequency of dry years in recent decades.

  1. Design of alluvial Egyptian irrigation canals using artificial neural networks method

    Directory of Open Access Journals (Sweden)

    Hassan Ibrahim Mohamed

    2013-06-01

    Full Text Available In the present study, artificial neural networks method (ANNs is used to estimate the main parameters which used in design of stable alluvial channels. The capability of ANN models to predict the stable alluvial channels dimensions is investigated, where the flow rate and sediment mean grain size were considered as input variables and wetted perimeter, hydraulic radius, and water surface slope were considered as output variables. The used ANN models are based on a back propagation algorithm to train a multi-layer feed-forward network (Levenberg Marquardt algorithm. The proposed models were verified using 311 data sets of field data collected from 61 manmade canals and drains. Several statistical measures and graphical representation are used to check the accuracy of the models in comparison with previous empirical equations. The results of the developed ANN model proved that this technique is reliable in such field compared with previously developed methods.

  2. Reservoir Characterization, Production Characteristics, and Research Needs for Fluvial/Alluvial Reservoirs in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Cole, E.L.; Fowler, M.L.; Jackson, S.R.; Madden, M.P.; Raw-Schatzinger, V.; Salamy, S.P.; Sarathi, P.; Young, M.A.

    1999-04-28

    The Department of Energy's (DOE's) Oil Recovery Field Demonstration Program was initiated in 1992 to maximize the economically and environmentally sound recovery of oil from known domestic reservoirs and to preserve access to this resource. Cost-shared field demonstration projects are being initiated in geology defined reservoir classes which have been prioritized by their potential for incremental recovery and their risk of abandonment. This document defines the characteristics of the fifth geological reservoir class in the series, fluvial/alluvial reservoirs. The reservoirs of Class 5 include deposits of alluvial fans, braided streams, and meandering streams. Deposit morphologies vary as a complex function of climate and tectonics and are characterized by a high degree of heterogeneity to fluid flow as a result of extreme variations in water energy as the deposits formed.

  3. Comparative Study Of Alluvial Cnidion-Type Meadows In The Lower Danube River Basin

    Directory of Open Access Journals (Sweden)

    Schneider-Binder Erika

    2014-10-01

    Full Text Available Alluvial Cnidion-type meadows (Habitat type 6440 of the Habitats Directive, mostly characteristic for the lower courses of large rivers in continental climate conditions of Europe are presented from the Lower Danube upstream the municipality of Giurgiu (river-km 510-524. The ecological requirements of the characteristic species, as well as their sensitivity to human-induced changes that derive from regular flooding, drainage, intensification of use and/or abandonment, are highlighted; these changes frequently lead to a decrease of biodiversity of the Cnidion-type meadows or to their total loss The studied meadows are compared with similar alluvial meadows from other sites of the lower Danube River basin. Finally, the strong interlocking of Cnidion type meadows with those of the Agropyro-Rumicion, Molinion and Deschampsion caespitosae alliances are discussed.

  4. The Importance of Lower Mississippi River Alluvial Valley Reforestation and Wetland Restoration Sites to Wintering Migratory Birds; Annual Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Major efforts have been initiated in the Lower Mississippi River Alluvial Valley (LMA V. Fig. I) from within both the U.S. Departments of Interior and Agriculture to...

  5. The Importance of Lower Mississippi River Alluvial Valley Reforestation and Wetland Restoration Sites to Wintering Migratory Birds: 2002 Annual Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The annual report outlines the importance of conserving and restoring lands for migratory birds in the Lower Mississippi River Alluvial Valley.

  6. The Importance of Lower Mississippi River Alluvial Valley Reforestation and Wetland Restoration Sites to Wintering Migratory Birds: 2000 Annual Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The annual report outlines the importance of conserving and restoring lands for migratory birds in the Lower Mississippi River Alluvial Valley.

  7. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant hydraulic conductivity values for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The...

  8. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace aquifer encompasses...

  9. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant recharge values for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace and...

  10. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital water-level elevation contours for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace and...

  11. Colorado Plateau Rapid Ecoregion Assessment Management Question B4: Where are the alluvial aquifers and their recharge areas (if known)?

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — This map shows potential alluvial aquifers based on sand, gravel, and alluvium types in the surficial geology datasets of Arizona, Colorado, New Mexico, and Utah.

  12. Quantitative palaeodrainage analysis in the Pleistocene of the Po Plain (Italy)

    Science.gov (United States)

    Vezzoli, G.; Garzanti, E.; Sciunnach, D.

    2009-04-01

    During the Pleistocene, Po Plain deposits recorded repeated waxing and waning of Alpine ice caps, and thus provide an excellent opportunity to investigate the interactions between pronounced climatic fluctuations and background tectonic activity (Scardia et al., 2006), resulting in frequent changes of drainage patterns. A high-resolution Pleistocene stratigraphy, with a complete sedimentological, paleontological, petrographic-mineralogical, magneto-stratigraphic, and seismic data base, was recently obtained from eleven continuous cores drilled in the Lombardy Po Plain north of the Po River (ENI and Regione Lombardia, 2002). In the present study we focus on two cores in the proximal (Cilavegna) and distal plain (Pianengo), which best exemplify the drastic change in sedimentary systems and drainage patterns associated with the onset of major Pleistocene glaciations in the Alps (˜870ky; Muttoni et al., 2003). This climatic event is recorded by a regional unconformity (named R-unconformity by Muttoni et al., 2003), traced all across the Po Basin and encountered at -81 m depth in the Pianengo Core and at -98 m depth in the Cilavegna Core. The Cilavegna Core consists of metamorphiclastic floodplain sediments, capped by the R-unconformity and overlain by quartzofeldspathic braidplain deposits. The Pianengo Core consists of metamorphiclastic deltaic to floodpain sediments, capped by the R-unconformity and overlain by alluvial-fan gravels rich in carbonate pebbles; another unconformity at -39 m depth is overlain by metamorphiclastic braidplain deposits. Our quantitative approach to paleodrainage analysis is based on comprehensive information obtained from modern settings (Garzanti et al., 2004; 2006). End-member modelling and similarity analysis allows us to objectively compare detrital modes from modern and ancient deposits, and to reconstruct the evolution of sediment pathways through geologic time (Vezzoli and Garzanti 2009). The Cilavegna Core documents stepwise south

  13. Hydrogeological features conditioning trophic levels of quarry lakes in western Po plain (north-western Italy)

    Science.gov (United States)

    De Luca, Domenico Antonio; Castagna, Sara; Lasagna, Manuela

    2013-04-01

    Quarry lakes occur in plains areas due to the extraction of alluvial sand and gravel used for grout and concrete in the construction industry. Excavation depths can reach and intersect the groundwater surface, thus creating a lake. Because of the need to optimize efficiency, the number of active open pit mines has increased in recent years; consequently, the global number of pit lakes will increase in coming decades (Castendyk and Eary 2009; Klapper and Geller 2001; Castro and Moore 2000). Similar to natural lakes, pit lakes are subject to eutrophication process, both during and after quarrying activity; during mining activity, the eutrophic level is strongly controlled by the excavation method. In the Piedmont territory (north-western Italy) there are 70 active quarry lakes, corresponding to approximately 0.1% of the entire plain area. Quarry lakes, located primarily along the main rivers occur in alluvial deposits of the plain area and have average depths between 20 and 30 m (maximum of 60 m deep) and surface areas between 3 and 30 hectares (Castagna 2008). The present study describes the trophic status of 23 active quarry lakes in the Piedmont plain that were evaluated by applying classifications from scientific literature. Currently, the majority of the studied quarry lakes may be defined as mesotrophic or eutrophic according to the trophic state classifications. Based on historic data, lake trophic levels have increased over time, during active mining. At the end of mining activity, further deterioration of water quality was expected, especially for smaller lakes with minimal oxygen stratification and higher levels of nutrients and algal growth. In addition, the paper focuses on the pit lake water quality and pit dimension; From an environmental perspective the excavation of quarry lakes with an appreciable size will likely result in a better safeguard of water quality and enhanced possibilities for lake end use after the cessation of mining. Piedmont quarry

  14. Enigmatic Post-Glacial Degradation and Aggradation of Rivers on the Alberta Plains

    Science.gov (United States)

    Malowany, K. S.; osborn, G.; Wu, P. P.

    2011-12-01

    Rivers flowing eastward from the Canadian Rockies across the Alberta plains are situated in narrow flat-bottomed valleys on the order of 50 to 100 m below the plains surface. Post-Laurentide Ice Sheet river history is characterized by (a) incision into the general plains surface following deglaciation, (b) aggradation, soon thereafter, in which up to 25 m of alluvial fill was deposited in the new valleys, and (c) Holocene reincision into the fill, down to depths at least as great as those of the pre-fill valleys. This complicated history probably results from an interplay of (a) isostatic depression/ rebound, which is considered here using a Glacial Isostatic Adjustment model that incorporates the RF2 and RF3 earth models described by Wang et al. (2008) with the ICE4G deglaciation model of Peltier (1994), and (b) variations in sediment flux. The initial incision post-dates the retreat of the Laurentide Ice Sheet eastward across Alberta, ca. 14 ka, and pre-dates the ca. 11 ka alluvial fill. Incision cannot have resulted from general uplift provided by post-glacial isostatic rebound, because rebound was and is generally greater downstream where ice was thicker. Hence river gradients have generally decreased because of rebound. Incision more likely resulted from increased gradients provided by isostatic depression under the center of the ice sheet, relative to the plains gradient that would exist without ice effects. Temporary increased gradients on particular reaches of rivers were provided by the passage across Alberta of the slope of a peripheral bulge on the margin of the isostatic depression. However, some reaches of the rivers have orientations that preclude an obvious connection to bulge gradients. The switch from degradation to aggradation in early post-glacial time was proposed to be a result of decreasing river gradients due to rebound, by Kellerhals and Shaw (1982), but later considered to be a result of influx of paraglacial sediments from the Canadian

  15. Debris-flow dominance of alluvial fans masked by runoff reworking and weathering.

    OpenAIRE

    Haas, T.; Ventra, D.; Carbonneau, P. E.; Kleinhans, M. G.

    2014-01-01

    Arid alluvial fan aggradation is highly episodic and fans often comprise active and inactive sectors. Hence the morphology and texture of fan surfaces are partly determined by secondary processes of weathering and erosion in addition to primary processes of aggradation. This introduces considerable uncertainty in the identification of formative processes of terrestrial and Martian fans from aerial and satellite imagery. The objectives of this study are (i) to develop a model to describe the s...

  16. Spatial variability and prediction modeling of groundwater arsenic distributions in the shallowest alluvial aquifers in Bangladesh

    OpenAIRE

    Shamsudduha, M.

    2007-01-01

    Elevated arsenic in groundwater is the greatest environmental problem in Bangladesh. Spatial variability of arsenic in groundwater has been examined by semivariogram analysis that revealed high degree of small-scale spatial variability in alluvial aquifers. Small-scale variability of arsenic concentrations, indicated by high "nugget" values in semivariograms, is associated with heterogeneity in local-scale geology and geochemical processes. In unsampled locations, arsenic concentrations have ...

  17. Managed aquifer recharge by using spreading basin methods on alluvial fans: a general overview of the situation in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Hida, N.

    2009-07-01

    In this paper, the author reviews the present situation of managed aquifer recharge (MAR) by using basin method as of 2009 in Japan. Most of the MAR basin is carried in the area of alluvial fans. The enhancing groundwater resources in the Rokugo alluvial aquifer has resulted in sustain ability for the groundwater environment, especially in the distal fan. As a recent tendency, the MAR basin contributes to sustainable aquifer management in alluvium and is spreading in Japan. (Author)

  18. Water-level change, High Plains aquifer, 2005 to 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2005 to 2009, in feet. The High Plains aquifer underlies...

  19. Water-level change, High Plains aquifer, 2000 to 2005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2000 to 2005, in feet. The High Plains aquifer underlies...

  20. Water-level change, High Plains aquifer, 1995 to 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1995 to 2000, in feet. The High Plains aquifer underlies...

  1. Water-level change, High Plains aquifer, 1980 to 1995

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1980 to 1995, in feet. The High Plains aquifer underlies...

  2. Impacts of hydroelectric dams on alluvial riparian plant communities in eastern Brazilian Amazonian

    Directory of Open Access Journals (Sweden)

    LEANDRO VALLE FERREIRA

    2013-09-01

    Full Text Available The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity.

  3. Self-similar growth of an alluvial fan fed with bimodal sediment

    Science.gov (United States)

    Delorme, Pauline; Voller, Vaughan; Paola, Chris; Devauchelle, Olivier; Lajeunesse, Eric; Barrier, Laurie; Métivier, François

    2016-04-01

    At the outlet of mountain ranges, rivers flow onto flatter lowlands. The associated change of slope causes sediment deposition. As the river is free to move laterally, it builds conical sedimentary structures called alluvial fans. Their location at the interface between erosional and depositional areas makes them valuable sedimentary archives. To decipher these sedimentary records, we need to understand the dynamics of their growth. We carried out a series of experiments to investigate the growth of alluvial fans fed with mixed sediments. The density difference between silica and coal sediments mimics a bimodal grain-size distribution in nature. The sediment and water discharges are constant during an experiment. During the run, we track the evolution of the surface pattern by digital imaging. At the end of each run, we acquire the fan topography using a scanning laser. Finally, we cut a radial cross section to visualize the sedimentary deposit. We observe there is a distinct slope break at the transition that dominates the overall curvature of the fan surface. Based on mass conservation and observations, we propose that this alluvial fan grows in a self-similar way, thus causing the transition between silica and coal deposits to be a straight line. The shape of the experimental transition accords with this prediction.

  4. Integrated hydrological modeling of the North China Plain and implications for sustainable water management

    Directory of Open Access Journals (Sweden)

    H. Qin

    2013-10-01

    Full Text Available Groundwater overdraft has caused fast water level decline in the North China Plain (NCP since the 1980s. Although many hydrological models have been developed for the NCP in the past few decades, most of them deal only with the groundwater component or only at local scales. In the present study, a coupled surface water–groundwater model using the MIKE SHE code has been developed for the entire alluvial plain of the NCP. All the major processes in the land phase of the hydrological cycle are considered in the integrated modeling approach. The most important parameters of the model are first identified by a sensitivity analysis process and then calibrated for the period 2000–2005. The calibrated model is validated for the period 2006–2008 against daily observations of groundwater heads. The simulation results compare well with the observations where acceptable values of root mean square error (RMSE (most values lie below 4 m and correlation coefficient (R (0.36–0.97 are obtained. The simulated evapotranspiration (ET is then compared with the remote sensing (RS-based ET data to further validate the model simulation. The comparison result with a R2 value of 0.93 between the monthly averaged values of simulated actual evapotranspiration (AET and RS AET for the entire NCP shows a good performance of the model. The water balance results indicate that more than 70% of water leaving the flow system is attributed to the ET component, of which about 0.25% is taken from the saturated zone (SZ; about 29% comes from pumping, including irrigation pumping and non-irrigation pumping (net pumping. Sustainable water management analysis of the NCP is conducted using the simulation results obtained from the integrated model. An effective approach to improve water use efficiency in the NCP is by reducing the actual ET, e.g. by introducing water-saving technologies and changes in cropping.

  5. Natural hazards on alluvial fans: the debris flow and flash flood disaster of December 1999, Vargas state, Venezuela

    Science.gov (United States)

    Larsen, Matthew C.; Wieczorek, Gerald F.; Eaton, L.S.; Torres-Sierra, Heriberto; Sylva, Walter F.

    2001-01-01

    Large populations live on or near alluvial fans in locations such as Los Angeles, California, Salt Lake City, Utah, Denver, Colorado, and lesser known areas such as Sarno, Italy, and Vargas, Venezuela. Debris flows and flash floods occur episodically in these alluvial fan environments, and place many communities at high risk during intense and prolonged rainfall. In December 1999, rainstorms induced thousands of landslides along the Cordillera de la Costa, Vargas, Venezuela. Rainfall accumulation of 293 mm during the first 2 weeks of December was followed by an additional 911 mm of rainfall on December 14 through 16. Debris flows and floods inundated coastal communities resulting in a catastrophic death toll of as many as 30,000 people. Flash floods and debris flows caused severe property destruction on alluvial fans at the mouths of the coastal mountain drainage network. In time scales spanning thousands of years, the alluvial fans along this Caribbean coastline are dynamic zones of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise abruptly from the Caribbean Sea, the alluvial fans provide practically the only flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. KEY TERMS: Debris flows, flash floods, alluvial fans, natural hazards, landslides, Venezuela

  6. Rapid delineation of alluvial fans using IfSAR-derived DEM for selected provinces in the Philippines

    Science.gov (United States)

    Ortiz, Iris Jill; Aquino, Dakila; Norini, Gianluca; Narod Eco, Rodrigo; Mahar Lagmay, Alfredo

    2015-04-01

    Alluvial fans are fan-shaped geomorphic features formed when sediments from a watershed are transported and deposited downstream via tributaries flowing out from the sudden break of a slope. Hazards usually associated with alluvial fans are flooding and debris flows. In this study, we used an Interferometric Synthetic Aperture Radar-derived digital elevation model of Pangasinan and Nueva Ecija Provinces in the Philippines to identify and delineate alluvial fans. Primary parameters considered include the geomorphic characteristics of the catchment area, stream network and slopes ranging from 0.11 to 8 degrees. Using this method, 12 alluvial fans were identified in Pangasinan and 16 in Nueva Ecija with areas ranging from 0.35 to 80 sq. km. The largest fan identified is the Mangatarem-Aguilar fan in Pangaisnan with a total area of 80.87 sq km while the Gabaldon fan in Nueva Ecija with total area of 48.11 sq km. We observed from the results that some alluvial fans have multiple feeder streams, and others have overlapping lateral extents with adjacent fans. These overlapping fans are called bajadas. In addition, the general location of fans and their apices in the two provinces appear to coincide with segments of the Philippines Fault System. There are about people 1.4 million living within these alluvial fans. Mapping and characterizing and identifying their associated hazards is crucial in the disaster preparedness efforts of the exposed population.

  7. Pedogeographic regionalization of the Pomurje plain

    Directory of Open Access Journals (Sweden)

    Franc Lovrenčak

    1991-12-01

    Full Text Available The paper deals with the pedogeographic regionalization of the Pomurje plain (Northeast Slovenia. With regard to differences in parent material, landforms, and hydrographic characteristics, the soil cover is ranked into two pedogeographic regions. Each of them is furthermore divided into several subregions grouped together according to related soil groups.

  8. Great plains regional climate assessment technical report

    Science.gov (United States)

    The Great Plains region (GP) plays important role in providing food and energy to the economy of the United States. Multiple climatic and non-climatic stressors put multiple sectors, livelihoods and communities at risk, including agriculture, water, ecosystems and rural and tribal communities. The G...

  9. Porosity Prediction of Plain Weft Knitted Fabrics

    Directory of Open Access Journals (Sweden)

    Muhammad Owais Raza Siddiqui

    2014-12-01

    Full Text Available Wearing comfort of clothing is dependent on air permeability, moisture absorbency and wicking properties of fabric, which are related to the porosity of fabric. In this work, a plug-in is developed using Python script and incorporated in Abaqus/CAE for the prediction of porosity of plain weft knitted fabrics. The Plug-in is able to automatically generate 3D solid and multifilament weft knitted fabric models and accurately determine the porosity of fabrics in two steps. In this work, plain weft knitted fabrics made of monofilament, multifilament and spun yarn made of staple fibers were used to evaluate the effectiveness of the developed plug-in. In the case of staple fiber yarn, intra yarn porosity was considered in the calculation of porosity. The first step is to develop a 3D geometrical model of plain weft knitted fabric and the second step is to calculate the porosity of the fabric by using the geometrical parameter of 3D weft knitted fabric model generated in step one. The predicted porosity of plain weft knitted fabric is extracted in the second step and is displayed in the message area. The predicted results obtained from the plug-in have been compared with the experimental results obtained from previously developed models; they agreed well.

  10. Necrotizing fasciitis : plain radiographic and CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Dae; Park, Jeong Hee; Jeon, Hae Jeong; Lim, Jong Nam; Heo, Tae Haeng; Park, Dong Rib [Konkuk Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-11-01

    To evaluate the plain radiographic and CT findings of the necrotizing fasciitis. We retrospectively reviewed the radiologic findings of 4 cases with necrotizing fasciitis. Three cases were proven pathologically. We evaluated pattern and extent of the gas shadows in plain films. CT findings were analysed, with emphasis on : (a) gas pattern, (b) extent, (c) location and involved site, (d) associated focal abscess, and (e) swelling of the adjacent muscles. On plain radiographs, four cases showed streaky or mottled gas densities in the pelvis, three cases in the perineum, one case in the abdomen, and two cases in the thigh. On CT images, gas pattern was mottled and streaky appearance with swelling of the adjacent muscles. Gas shadows located in the extraperitoneal space in four cases, fascial layer in four cases, and subcutaneous layer in four cases. There were gas shadows in pelvic wall, perineum, abdominal wall, buttock, thigh, and scrotum. Focal low density lesion suggestive of focal abscess was not visualized. Plain radiography is useful for early diagnosis of the necrotizing fasciitis and CT is very useful for detection of precise location and extent of the disease. CT is also useful for differentiation of necrotizing fasciitis from focal abscess and cellulitis.

  11. The geologic story of the Great Plains

    Science.gov (United States)

    Trimble, Donald E.

    1980-01-01

    The Great Plains! The words alone create a sense of space and a feeling of destiny a challenge. But what exactly is this special part of Western America that contains so much of our history? How did it come to be? Why is it different?

  12. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  13. A sedimentary origin for intercrater plains north of the Hellas basin: Implications for climate conditions and erosion rates on early Mars

    Science.gov (United States)

    Salese, Francesco; Ansan, Veronique; Mangold, Nicolas; Carter, John; Ody, Anouck; Poulet, Francois; Ori, Gian Gabriele

    2016-11-01

    Understanding the origin (volcanic or sedimentary) and timing of intercrater plains is crucial for deciphering the geological evolution of Mars. We have produced a detailed geological map of the intercrater plains north of the Hellas basin, based on images from the Mars Express High-Resolution Stereo Camera, the Mars Reconnaissance High-Resolution Imaging Science Experiment, and Context. Erosional windows and fresh impact craters provide a way of studying the lithology of intercrater plain units. They are composed predominantly of light-toned sedimentary rocks with subhorizontal bedding over a broad extent (greater than tens of kilometers), showing cross-bedding stratifications locally. The broad extent, geometry, and flat topography of these sediments favor a formation by aqueous processes (alluvial and lacustrine) rather than airfall (eolian and volcaniclastic). The Late Noachian ( 3.7 Ga) sedimentary plains are locally covered by dark-toned, rough-textured lava flows of Late Hesperian age ( 3.3 Ga). Fe/Mg phyllosilicates were detected within sedimentary rocks, whereas volcanic rocks contain pyroxene and lack signatures of alteration, in agreement with interpretations made from texture and morphology. In erosional windows, the superimposition of sedimentary rocks by younger volcanic flows enables the estimation of an erosion rate of 1000 nm yr-1 during the Hesperian period (3.3-3.7 Ga). Thus, our study shows that an intense sedimentary cycle occurred on the northern rim of the Hellas basin before and during the Late Noachian, leading to the formation of widespread sedimentary plains, which were then eroded, in agreement with a gradual change in the climatic conditions in this period, and later covered by volcanic flows.

  14. Preliminary report on arsenic and heavy metals contents in soils and stream bed sediments of Cornia, Bruna and Alma coastal plains (Southern Tuscany

    Directory of Open Access Journals (Sweden)

    Dughetti F.

    2013-04-01

    Full Text Available The Department of Earth Sciences of University of Florence has conducted over the past ten years, numerous studies about the distribution of arsenic and heavy metals in mineralized areas of Tuscany, particularly in the Pecora basin. The area hosts several polymetallic ore bodies and a pyrite ore deposit. The studies have identified several geochemical anomalies (As, Cu, Pb, Zn… both in the areas which host the ore bodies and in the coastal plain (Scarlino Plain. To increase the knowledge concerning the distribution of As and heavy metals in other Tuscan coastal plains, research is under way in the alluvial plains of the Bruna, Cornia and Alma rivers. The preliminary analysis have focused on soils and stream sediments, to better understand the correlations between the downstream transport of rivers and the soils. We have made physic-chemical analysis, particle size analysis, mineralogical analysis for X-ray powder diffraction, chemical analysis for the determination of major element (X-ray Fluorescence and for the determination of 35 minor elements and traces (AAS and ICP.Preliminary data show high concentrations of several elements (As, Zn, Co…. The concentrations of these elements in soils and stream bed sediments are not always consistent; in particular we have found higher concentrations in soils than in stream bed sediments in Cornia Plain, while the opposite happens in the Bruna basin. Therefore the natural processes of rocks weathering does not seem to have affected uniformly. The distribution of As and heavy metals in soils and stream bed sediments of the all three basins of interest are still under investigation.

  15. Potential impacts of damming the Juba Valley, western Somalia: Insights from geomorphology and alluvial history

    Science.gov (United States)

    Williams, Martin

    2014-05-01

    In 1988 plans were well advanced to dam the Juba River in western Somalia. The aims of the Baardheere Dam Project were to generate hydroelectric power for the capital Mogadishu, and to provide water for irrigation in the Juba Valley. A reconnaissance survey on foot along 500 km of the river upstream of the proposed dam site at Baardheere and detailed geomorphic mapping from air photos provided a basis for reconstructing the late Quaternary alluvial history of the river and for assessing the potential impact of the proposed dam. The Juba River rises in the Ethiopian Highlands and is the only river in Somalia that flows to the sea. Its history reflects climatic events in Ethiopia, where the Rift Valley lakes were very low during the LGM (21±2 ka), and high for about 5, 000 years before and after then. Cave deposits in Somalia indicate wetter conditions at 13, 10, 7.5 and 1.5 ka. Alluvial terraces in the Juba Valley range in age from late Pleistocene to late Holocene but only attain a few metres above the present floodplain. This is because the dry tributary valleys contain limestone caves and fissures that divert any high flows from the parent river underground, a process not known when the project was first approved. The oldest preserved terrace was cemented by calcrete by 40 ka. Alluvial gravels were deposited at the outlet of dry tributary valleys during times of episodic high-energy flow between 26 ka and 28 ka. Finely laminated shelly sands accumulated at 10 ka to form the 5 m terrace. The 2 m terrace was laid down 3.2 ka ago as a slackwater deposit. The lack of high-level alluvial terraces raises doubts over plans to dam the river, since rapid leakage would occur from side valleys and the reservoir would not attain the height needed to generate hydroelectric power. It would submerge all existing arable land along the river. Finally, the presence in the late Holocene alluvium of the sub-fossil gastropods Bulinus truncatus and Biomphalaria pfeifferi, which are

  16. Analysis of the Sediment Hydrograph of the alluvial deltas in the Apalachicola River, Florida

    Science.gov (United States)

    Daranpob, A.; Hagen, S.; Passeri, D.; Smar, D. E.

    2011-12-01

    Channel and alluvial characteristics in lowlands are the products of boundary conditions and driving forces. The boundary conditions normally include materials and land cover types, such as soil type and vegetation cover. General driving forces include discharge rate, sediment loadings, tides and waves. Deltas built up of river-transported sediment occur in depositional zones of the river mouth in flat terrains and slow currents. Total sediment load depends on two major abilities of the river, the river shear stress and capacity. The shear stress determines transport of a given sediment grain size, normally expressed as tractive force. The river capacity determines the total load or quantity of total sediments transported across a section of the river, generally expressed as the sediment loading rate. The shear stress and sediment loading rate are relatively easy to measure in the headwater and transfer zones where streams form a v-shape valley and the river begins to form defined banks compared to the deposition zone where rivers broaden across lower elevation landscapes creating alluvial forms such as deltas. Determinations of deposition and re-suspension of sediment in fluvial systems are complicated due to exerting tidal, wind, and wave forces. Cyclic forces of tides and waves repeatedly change the sediment transport and deposition rate spatially and temporally in alluvial fans. However, the influence decreases with water depth. Understanding the transport, deposition, and re-suspension of sediments in the fluvial zone would provide a better understanding of the morphology of landscape in lowland estuaries such as the Apalachicola Bay and its estuary systems. The Apalachicola River system is located in the Florida Panhandle. Shelf sedimentation process is not a strong influence in this region because it is protected by barrier islands from direct ocean forces of the Gulf of Mexico. This research explores the characteristic of suspended sediment loadings in

  17. Climatic and Tectonic Controls on Alluvial Fan Evolution: The Lost River Range, Idaho

    Science.gov (United States)

    Phillips, R. J.; Pierce, J. L.; Sharp, W. D.; Pierce, K. L.

    2006-12-01

    In the northern Basin &Range, alluvial fans developed along the Lost River range-front consist of several distinct inset fan segments with concave-up radial profiles. Multiple large radius (>5 km), shallow (2- 3°), alluvial fans extend across and beyond the active, ~140-km-long, normal Lost River fault. These large fans are relict features, formed by major sheetfloods that occurred intermittently between ~15-180 ka. More recent deposition has been dominated by debris-flows that form small-radius (cuts through gravelly fan deposits, indicates that the fan soils are geochemically suitable for uranium-series dating (median U=7ppm, 232Th=0.09ppm, 232Th/230Th=154). 230Th/U analysis of these calcic soils can thus provide precise temporal constraints on intervals of surface stability and subsequent soil formation. The oldest fan surface (Qfo1, 178+/-8 ka), exposed within the footwall of the trench, suggests an interval of surface stability, indicating that the fan was likely abandoned due to incision early in MIS 6. Incision may have resulted from surface faulting along the Arco segment of the Lost River fault, but could relate to changes in stream power or sediment supply associated with climatic change or with auto-cyclic variations within the drainage basin. A younger incised and faulted fan surface (Qfo2, 69+/-6 ka), likely represents active alluviation at the beginning of MIS 4 and, since it formed as hanging-wall alluvial gravel, provides age limits on an episode of fault displacement between Qfo1 and Qfo2. In situ pedogenic carbonate coats on sub-angular gravels within the colluvial fault wedge date at 68+/-2 ka, suggesting that either faulting occurred soon after Qfo2 stabilized or that soil carbonate coats were recycled into the colluvial wedge from the faulted surface. Further studies in the Lost River Range will assess the timing of fan deposition, surface stabilization and fault activity since the late Pleistocene using coupled application of Optically

  18. Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California

    Science.gov (United States)

    Machette, Michael N.; Slate, Janet L.; Phillips, Fred M.

    2008-01-01

    We have used terrestrial cosmogenic nuclides (TCN) to establish the age of some of the most extensive Quaternary alluvial fans in Death Valley, California. These intermediate-age alluvial fans are most extensive on the western side of the valley, where tectonic deformation is considerably less pronounced than on the eastern side of the valley. These fans are characterized by a relatively smooth, densely packed desert pavement formed by well-varnished (blackened) clasts. These surfaces have been mapped as the Q2 gravel by previous workers and as unit Qai (intermediate age) by us. However, the intermediate-age gravels probably contain multiple subunits, as evidenced by slight differences in morphologic expression, soil formation, and inset geomorphic relations. The TCN technique used herein sums the cosmogenic 36Cl in approximately 2.5-meter-deep profiles through soil and host alluvium, thus avoiding some of the problems associated with the more typical surface-exposure dating of boulders or smaller clasts. Our TCN 36Cl dating of 12 depth profiles indicates that these intermediate-age (Qai) alluvial fans range from about 100 to 40 kilo-annum (ka), with a mean age of about 70 ka. An alternative interpretation is that alluvial unit Qai was deposited in two discrete episodes from 90 to 80 ka and from 60 to 50 ka, before and after MIS (marine oxygen-isotope stage) 4 (respectively). Without an intermediate-age unit, such as MIS 4 lake deposits, we can neither disprove nor prove that Qai was deposited in two discrete intervals or over a longer range of time. Thus, in Death Valley, alluvial unit Qai largely brackets MIS 4, which is not associated with a deep phase of Lake Manly. These Qai fans extend to elevations of about -46 meters (150 feet below sea level) and have not been transgressed by Lake Manly, suggesting that MIS 4 or MIS 2 lakes were rather shallow in Death Valley, perhaps because they lacked inflow from surface runoff of the Sierra Nevada drainages through

  19. Episodic bedrock erosion by gully-head migration, Colorado High Plains, USA

    Science.gov (United States)

    Rengers, Francis; Tucker, G.E.; Mahan, Shannon

    2016-01-01

    This study explores the frequency of bedrock exposure in a soil-mantled low-relief (i.e. non-mountainous) landscape. In the High Plains of eastern Colorado, gully headcuts are among the few erosional features that will incise through the soil mantle to expose bedrock. We measured the last time of bedrock exposure using optically stimulated luminescence dating of alluvial sediment overlying bedrock in gully headcuts. Our dating suggests that headcuts in adjacent gullies expose bedrock asynchronously, and therefore, the headcuts are unlikely to have been triggered by a base-level drop in the trunk stream. This finding supports the hypothesis that headcuts can develop locally in gullies as a result of focused scour in locations where hydraulic stress during a flash flood is sufficiently high, and/or ground cover is sufficiently weak, to generate a scour hole that undermines vegetation. Alluvium dating also reveals that gullies have been a persistent part of this landscape since the early Holocene. 

  20. Geochronology and Geomorphology of the Pioneer Archaeological Site (10BT676), Upper Snake River Plain, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Keene, Joshua L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-04-01

    The Pioneer site in southeastern Idaho, an open-air, stratified, multi-component archaeological locality on the upper Snake River Plain, provides an ideal situation for understanding the geomorphic history of the Big Lost River drainage system. We conducted a block excavation with the goal of understanding the geochronological context of both cultural and geomorphological components at the site. The results of this study show a sequence of five soil formation episodes forming three terraces beginning prior to 7200 cal yr BP and lasting until the historic period, preserving one cultural component dated to ~3800 cal yr BP and multiple components dating to the last 800 cal yr BP. In addition, periods of deposition and stability at Pioneer indicate climate fluctuation during the middle Holocene (~7200-3800 cal yr BP), minimal deposition during the late Holocene, and a period of increased deposition potentially linked to the Little Ice Age. In addition, evidence for a high-energy erosion event dated to ~3800 cal yr BP suggest a catastrophic flood event during the middle Holocene that may correlate with volcanic activity at the Craters of the Moon lava fields to the northwest. This study provides a model for the study of alluvial terrace formations in arid environments and their potential to preserve stratified archaeological deposits.

  1. A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing Wetland Functions of Forested Wetlands in Alluvial Valleys of the Coastal Plain of the Southeastern United States

    Science.gov (United States)

    2013-04-01

    blackgum, laurel oak, loblolly pine , slash pine (P. elliottii), and sometimes longleaf pine (P. palustris). Subcanopy species include spicebush, (Lindera...eventually become organic soil flats. They typically occur in relatively humid climates. Pine flatwoods with hydric soils are an example of mineral soil...horizontal Headwater wetlands Avalanche chutes Flat (mineral soil) Precipitation Vertical Wet pine flatwoods Large playas Flat (organic soil

  2. Change of ancient hydrology net in Northeast China Plain

    Institute of Scientific and Technical Information of China (English)

    Hui QU; Yu CHU; Fenglong ZHANG; Fuli QI; Xiangkui YANG

    2006-01-01

    Comparing with lithofacies palaeogeography of several great plains, the authors analyzed four great plains in Quaternary diastrophism, the sedimentary facies, sedimentary environment and their evolution from the independent embryonic and river system of ancient Heilongjiang finally to the Halar highland, Songnen Plain, Sanjiang Plain, the Xingkai Lake Plain and various river systems, collected the unification outside the system of Heilongjiang River to release into the sea, south ancient Xialiao River finally piracy Dongliao River, Xialiao River had released into the sea the ancient water law vicissitude and the evolved rule.

  3. Stratigraphic control on earthquake-induced liquefaction: A case study from the Central Po Plain (Italy)

    Science.gov (United States)

    Amorosi, A.; Bruno, L.; Facciorusso, J.; Piccin, A.; Sammartino, I.

    2016-11-01

    Studies on earthquake-induced liquefaction tied to high-resolution stratigraphic analysis have been rarely undertaken. We report the results of a multidisciplinary study from the Quistello-Moglia area, in the central Po Plain (northern Italy). In this region, combined stratigraphic, sedimentological, geotechnical, and geochemical data allowed assessment of liquefaction potential and identification of the primary source for liquefaction, following the second main shock (Mw 6) of the 2012 Po Plain earthquake. Using Cone Penetration Test (CPT)-based simplified procedures for liquefaction hazard evaluation, we assessed the highest liquefaction potential of Holocene, fluvial-channel and related (crevasse/levee) fine sand-silt facies encased in thick, mud-prone floodplain and swamp successions. The liquefaction potential, and the intensity of the manifestations induced on the ground surface, decreased for the vertically-amalgamated, sheet-like Pleistocene sandy fluvial units encountered at depths greater than 13 m. Floodplain and swamp deposits were virtually non-liquefiable. In the Quistello area, the compositional characterization of sands that were liquefied and extruded during the 2012 earthquake reveals the diagnostic geochemical fingerprint of sediment carried by the Po River, as opposed to the Apennine composition of surficial sediments. These data rule out proximity of liquefied layers to the surface, and attest the buried, meandering Po River system at depths of 7-10 m most likely representing the source for the liquefied sand that vented to the surface. Similarly, at Moglia, liquefied sands were likely sourced from loose and saturated, ribbon-shaped, fluvial sand bodies encased in mud, though at shallower (4-7 m) depths. Pronounced liquefaction phenomena in alluvial plain systems are commonly believed to be associated primarily with elongate topographic ridges following paleo-river courses. Here, we document that under favorable stratigraphic conditions

  4. Regional water quality patterns in an alluvial aquifer: direct and indirect influences of rivers.

    Science.gov (United States)

    Baillieux, A; Campisi, D; Jammet, N; Bucher, S; Hunkeler, D

    2014-11-15

    The influence of rivers on the groundwater quality in alluvial aquifers can be twofold: direct and indirect. Rivers can have a direct influence via recharge and an indirect one by controlling the distribution of fine-grained, organic-carbon rich flood deposits that induce reducing conditions. These direct and indirect influences were quantified for a large alluvial aquifer on the Swiss Plateau (50km(2)) in interaction with an Alpine river using nitrate as an example. The hydrochemistry and stable isotope composition of water were characterized using a network of 115 piezometers and pumping stations covering the entire aquifer. Aquifer properties, land use and recharge zones were evaluated as well. This information provided detailed insight into the factors that control the spatial variability of groundwater quality. Three main factors were identified: (1) diffuse agricultural pollution sources; (2) dilution processes resulting from river water infiltrations, revealed by the δ(18)OH2O and δ(2)HH2O contents of groundwater; and (3) denitrification processes, controlled by the spatial variability of flood deposits governed by fluvial depositional processes. It was possible to quantify the dependence of the nitrate concentration on these three factors at any sampling point of the aquifer using an end-member mixing model, where the average nitrate concentration in recharge from the agricultural area was evaluated at 52mg/L, and the nitrate concentration of infiltrating river at approximately 6mg/L. The study shows the importance of considering the indirect and direct impacts of rivers on alluvial aquifers and provides a methodological framework to evaluate aquifer scale water quality patterns.

  5. Evaluation of groundwater recharge in Choushui River alluvial fan and Mingchu Basin for specific rainfall events

    Science.gov (United States)

    Lin, Zong Sheng; Chen, Jui-Sheng; Jang, Cheng-Shin

    2014-05-01

    Sound groundwater resources planning and management are lack in the Choushui River alluvial fan, resulting in the occurrence of serious land subsidence and seawater intrusion. Even the disasters induced by overpumping of groundwater pose a potential threat on the Taiwan High Speed Rail. In addition to improving the water resources management in the alluvial fan, the development of groundwater resources in the neighboring hills. Mingchu Basin, which is located on the midstream segment of the Choushui River and comprised of the gravel formation of Pleistocene, is an effective solution to resolve the problem in limited water resources. Moreover, the Dongpurui River and Qingshui River both converge into Choushui River in this basin. Because of wide drainage areas and good hydrogeological conditions, the Mingchu Basin is considered a high potential recharging region of groundwater. This work is to evaluate the groundwater recharge in the Choushui River alluvial fan and Mingchu Basin, using the WASH123D model equipped with the Groundwater Modeling System (GMS) to simulate the interaction of surface water and groundwater for specific five rainfall events. This study particularly focuses on the simulation of the groundwater flow, and evaluates the effect of different rainfall events on the groundwater recharge. First, to meet in-situ hydrogeological structure and hydraulic parameters, the GMS is used to construct hydrogeological database, mesh, hydrogeological parameters, initial condition and boundary conditions. Then, simulated parameters, such as hydraulic conductivity and pumping rates, need to be calibrated and verified in the model. After the calibration and verification, the simulated groundwater flow can reflect actual groundwater situation. Finally, when specific five rainfall events impose on the ground, groundwater recharge can be determined using the groundwater model.

  6. Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings

    Science.gov (United States)

    Zhang, Yong; Green, Christopher T.; Baeumer, Boris

    2014-01-01

    Time-nonlocal transport models can describe non-Fickian diffusion observed in geological media, but the physical meaning of parameters can be ambiguous, and most applications are limited to curve-fitting. This study explores methods for predicting the parameters of a temporally tempered Lévy motion (TTLM) model for transient sub-diffusion in mobile–immobile like alluvial settings represented by high-resolution hydrofacies models. The TTLM model is a concise multi-rate mass transfer (MRMT) model that describes a linear mass transfer process where the transfer kinetics and late-time transport behavior are controlled by properties of the host medium, especially the immobile domain. The intrinsic connection between the MRMT and TTLM models helps to estimate the main time-nonlocal parameters in the TTLM model (which are the time scale index, the capacity coefficient, and the truncation parameter) either semi-analytically or empirically from the measurable aquifer properties. Further applications show that the TTLM model captures the observed solute snapshots, the breakthrough curves, and the spatial moments of plumes up to the fourth order. Most importantly, the a priori estimation of the time-nonlocal parameters outside of any breakthrough fitting procedure provides a reliable “blind” prediction of the late-time dynamics of subdiffusion observed in a spectrum of alluvial settings. Predictability of the time-nonlocal parameters may be due to the fact that the late-time subdiffusion is not affected by the exact location of each immobile zone, but rather is controlled by the time spent in immobile blocks surrounding the pathway of solute particles. Results also show that the effective dispersion coefficient has to be fitted due to the scale effect of transport, and the mean velocity can differ from local measurements or volume averages. The link between medium heterogeneity and time-nonlocal parameters will help to improve model predictability for non

  7. Hydrochemical evolution within a large alluvial groundwater resource overlying a shallow coal seam gas reservoir.

    Science.gov (United States)

    Owen, Daniel D R; Cox, Malcolm E

    2015-08-01

    A combination of multivariate statistical techniques, simple hydrochemical mixing models and inverse geochemical modelling was used to investigate the major hydrochemical evolutionary pathways of a large alluvial aquifer, the upper Condamine River alluvium, south-east Queensland, Australia. Hydrochemical similarities between alluvium and sedimentary bedrock groundwater imply some mixing between alluvial and sedimentary bedrock aquifers, but spatial assessment showed that this was localised around outcrops of sedimentary bedrock in upstream areas. Within the alluvium, a distinct shift towards a low salinity Na-HCO3 water type and a brackish Na-HCO3-Cl water type was obvious in two separate locations. Both of these water types are unique to the alluvium, and inverse modelling shows that they can evolve via a combination of in situ alluvial processes, including diffuse recharge of rainfall or river water or the evolution of basalt-derived groundwater via gypsum dissolution plagioclase weathering, cation exchange and some carbonate precipitation/dissolution. The evolution of these water types is potentially influenced by overlying sodic alkaline soils, and often is associated with a source of sulfate. Evapotranspiration is the dominant salinization process in the alluvium and increases in calcium cations during salinization indicate that brackish Na-HCO3-Cl groundwater in the underlying Walloon Coal Measures are unlikely to have a major influence on salinization in the alluvium. The most saline water types observed were endemic to shallow zones of the alluvium where evapotranspiration is likely. Results demonstrate that a combination of multivariate statistics and inverse geochemical modelling can be successfully used to delineate hydrochemical pathways in complex hydrogeological settings where a range of environmental and anthropogenic factors may be influencing the evolution of water types with similar hydrochemical compositions.

  8. Late Quaternary eolian and alluvial response to paleoclimate, Canyonlands, southeastern Utah

    Science.gov (United States)

    Reheis, M.C.; Reynolds, R.L.; Goldstein, H.; Roberts, H.M.; Yount, J.C.; Axford, Y.; Cummings, L.S.; Shearin, N.

    2005-01-01

    In upland areas of Canyonlands National Park, Utah, thin deposits and paleosols show late Quaternary episodes of eolian sedimentation, pedogenesis, and climate change. Interpretation of the stratigraphy and optically stimulated luminescence ages of eolian and nearby alluvial deposits, their pollen, and intercalated paleosols yields the following history: (1) Eolian deposition at ca. 46 ka, followed by several episodes of alluviation from some time before ca. 40 ka until after 16 ka (calibrated). (2) Eolian deposition from ca. 17 ka to 12 ka, interrupted by periods of pedogenesis, coinciding with late Pleistocene alluviation as local climate became warmer and wetter. (3) A wetter period from 12 to 8.5 ka corresponding to the peak of summer monsoon influence, during which soils formed relatively quickly by infiltration of eolian silt and clay, and trees and grasses were more abundant. (4) A drier period between ca. 8.5 and 6 ka during which sheetwash deposits accumulated and more desertlike vegetation was dominant; some dunes were reactivated at ca. 8 ka. (5) Episodic eolian and fluvial deposition during a wetter, cooler period that began at ca. 6 ka and ended by ca. 3-2 ka, followed by a shift to drier modern conditions; localized mobilization of dune sand has persisted to the present. These interpretations are similar to those of studies at the Chaco dune field, New Mexico, and the Tusayan dune field, Arizona, and are consistent with paleoclimate interpretations of pollen and packrat middens in the region. A period of rapid deposition and infiltration of eolian dust derived from distant igneous source terranes occurred between ca. 12 and 8 ka. Before ca. 17 ka, and apparently back to at least 45 ka, paleosols contain little or no such infiltrated dust. After ca. 8 ka, either the supply of dust was reduced or the more arid climate inhibited translocation of dust into the soils. ?? 2005 Geological Society of America.

  9. Heat Transfer Characterization Using Heat and Solute Tracer Tests in a Shallow Alluvial Aquifer

    Science.gov (United States)

    Dassargues, A.

    2013-12-01

    Very low enthalpy geothermal systems are increasingly considered for heating or cooling using groundwater energy combined with heat pumps. The design and the impact of shallow geothermal systems are often assessed in a semi-empirical way. It is accepted by most of the private partners but not by environmental authorities deploring a lack of rigorous evaluation of the mid- to long-term impact on groundwater. In view of a more rigorous methodology, heat and dye tracers are used for estimating simultaneously heat transfer and solute transport parameters in an alluvial aquifer. The experimental field site, is equipped with 21 piezometers drilled in alluvial deposits composed of a loam layer overlying a sand and gravel layer constituting the alluvial aquifer. The tracing experiment consisted in injecting simultaneously heated water and a dye tracer in a piezometer and monitoring evolution of groundwater temperature and tracer concentration in 3 control panels set perpendicularly to the main groundwater flow. Results showed drastic differences between heat transfer and solute transport due to the main influence of thermal capacity of the saturated porous medium. The tracing experiment was then simulated using a numerical model and the best estimation of heat transfer and solute transport parameters is obtained by calibrating this numerical model using inversion tools. The developed concepts and tests may lead to real projects of various extents that can be now optimized by the use of a rigorous and efficient methodology at the field scale. On the field: view from the injection well in direction of the pumping well through the three monitoring panels Temperature monitoring in the pumping well and in the piezometers of the three panels: heat transfer is faster in the lower part of the aquifer (blue curves) than in the upper part (red curves). Breakthrough curves are also more dispersed in the upper part with longer tailings.

  10. Coupling heat and chemical tracer experiments for estimating heat transfer parameters in shallow alluvial aquifers.

    Science.gov (United States)

    Wildemeersch, S; Jamin, P; Orban, P; Hermans, T; Klepikova, M; Nguyen, F; Brouyère, S; Dassargues, A

    2014-11-15

    Geothermal energy systems, closed or open, are increasingly considered for heating and/or cooling buildings. The efficiency of such systems depends on the thermal properties of the subsurface. Therefore, feasibility and impact studies performed prior to their installation should include a field characterization of thermal properties and a heat transfer model using parameter values measured in situ. However, there is a lack of in situ experiments and methodology for performing such a field characterization, especially for open systems. This study presents an in situ experiment designed for estimating heat transfer parameters in shallow alluvial aquifers with focus on the specific heat capacity. This experiment consists in simultaneously injecting hot water and a chemical tracer into the aquifer and monitoring the evolution of groundwater temperature and concentration in the recovery well (and possibly in other piezometers located down gradient). Temperature and concentrations are then used for estimating the specific heat capacity. The first method for estimating this parameter is based on a modeling in series of the chemical tracer and temperature breakthrough curves at the recovery well. The second method is based on an energy balance. The values of specific heat capacity estimated for both methods (2.30 and 2.54MJ/m(3)/K) for the experimental site in the alluvial aquifer of the Meuse River (Belgium) are almost identical and consistent with values found in the literature. Temperature breakthrough curves in other piezometers are not required for estimating the specific heat capacity. However, they highlight that heat transfer in the alluvial aquifer of the Meuse River is complex and contrasted with different dominant process depending on the depth leading to significant vertical heat exchange between upper and lower part of the aquifer. Furthermore, these temperature breakthrough curves could be included in the calibration of a complex heat transfer model for

  11. Geologic Characterization of Young Alluvial Basin-Fill Deposits from Drill-Hole Data in Yucca Flat, Nye County, Nevada

    Science.gov (United States)

    Sweetkind, Donald S.; Drake II, Ronald M.

    2007-01-01

    Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site in Nye County, Nevada, that has been the site of numerous underground nuclear tests; many of these tests occurred within the young alluvial basin-fill deposits. The migration of radionuclides to the Paleozoic carbonate aquifer involves passage through this thick, heterogeneous section of Tertiary and Quaternary rock. An understanding of the lateral and vertical changes in the material properties of young alluvial basin-fill deposits will aid in the further development of the hydrogeologic framework and the delineation of hydrostratigraphic units and hydraulic properties required for simulating ground-water flow in the Yucca Flat area. This report by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, presents data and interpretation regarding the three-dimensional variability of the shallow alluvial aquifers in areas of testing at Yucca Flat, data that are potentially useful in the understanding of the subsurface flow system. This report includes a summary and interpretation of alluvial basin-fill stratigraphy in the Yucca Flat area based on drill-hole data from 285 selected drill holes. Spatial variations in lithology and grain size of the Neogene basin-fill sediments can be established when data from numerous drill holes are considered together. Lithologic variations are related to different depositional environments within the basin such as alluvial fan, channel, basin axis, and playa deposits.

  12. Geologic Characterization of Young Alluvial Basin-Fill Deposits from Drill Hole Data in Yucca Flat, Nye County, Nevada

    Science.gov (United States)

    Sweetkind, Donald S.; Drake II, Ronald M.

    2007-01-01

    Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada, that has been the site of numerous underground nuclear tests; many of these tests occurred within the young alluvial basin-fill deposits. The migration of radionuclides to the Paleozoic carbonate aquifer involves passage through this thick, heterogeneous section of Tertiary and Quaternary rock. An understanding of the lateral and vertical changes in the material properties of young alluvial basin-fill deposits will aid in the further development of the hydrogeologic framework and the delineation of hydrostratigraphic units and hydraulic properties required for simulating ground-water flow in the Yucca Flat area. This report by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, presents data and interpretation regarding the three-dimensional variability of the shallow alluvial aquifers in areas of testing at Yucca Flat, data that are potentially useful in the understanding of the subsurface flow system. This report includes a summary and interpretation of alluvial basin-fill stratigraphy in the Yucca Flat area based on drill hole data from 285 selected drill holes. Spatial variations in lithology and grain size of the Neogene basin-fill sediments can be established when data from numerous drill holes are considered together. Lithologic variations are related to different depositional environments within the basin including alluvial fan, channel, basin axis, and playa deposits.

  13. Geologic Characterization of Young Alluvial Basin-Fill Deposits from Drill Hole Data in Yucca Flat, Nye County, Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    Donald S. Sweetkind; Ronald M. Drake II

    2007-01-22

    Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada, that has been the site of numerous underground nuclear tests; many of these tests occurred within the young alluvial basin-fill deposits. The migration of radionuclides to the Paleozoic carbonate aquifer involves passage through this thick, heterogeneous section of Tertiary and Quaternary rock. An understanding of the lateral and vertical changes in the material properties of young alluvial basin-fill deposits will aid in the further development of the hydrogeologic framework and the delineation of hydrostratigraphic units and hydraulic properties required for simulating ground-water flow in the Yucca Flat area. This report by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, presents data and interpretation regarding the three-dimensional variability of the shallow alluvial aquifers in areas of testing at Yucca Flat, data that are potentially useful in the understanding of the subsurface flow system. This report includes a summary and interpretation of alluvial basin-fill stratigraphy in the Yucca Flat area based on drill hole data from 285 selected drill holes. Spatial variations in lithology and grain size of the Neogene basin-fill sediments can be established when data from numerous drill holes are considered together. Lithologic variations are related to different depositional environments within the basin including alluvial fan, channel, basin axis, and playa deposits.

  14. Conceptual model of the Great Basin carbonate and alluvial aquifer system

    Science.gov (United States)

    Heilweil, Victor M.; Brooks, Lynette E.

    2011-01-01

    A conceptual model of the Great Basin carbonate and alluvial aquifer system (GBCAAS) was developed by the U.S. Geological Survey (USGS) for a regional assessment of groundwater availability as part of a national water census. The study area is an expansion of a previous USGS Regional Aquifer Systems Analysis (RASA) study conducted during the 1980s and 1990s of the carbonate-rock province of the Great Basin. The geographic extent of the study area is 110,000 mi2, predominantly in eastern Nevada and western Utah, and includes 165 hydrographic areas (HAs) and 17 regional groundwater flow systems.

  15. Determination of vulnerability areas to pollution: case of alluvial water table of Tebessa (East Algeria)

    Energy Technology Data Exchange (ETDEWEB)

    Djabri, L.; Hani, A.; Assassi, F.; Djprfi, S.

    2009-07-01

    This work related to the alluvial water table of Tebessa, which is characterised by a semi-dry climate and a very heterogeneous geology. To examine the pollution problem who seems exists, we have used two methods: the DRASTICS method who combines the information given by the seven parameters leading to the map of vulnerability to pollution and a second method that is based on hydrochemistry and take into account the results of the ratio Sr{sup 2}/Ca{sup 2}+. (Author)

  16. Optical dating using feldspar from Quaternary alluvial and colluvial sediments from SE Brazilian Plateau, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Tatumi, Sonia H. E-mail: tatumi@fatecsp.br; Peixoto, Maria Naise O.; Moura, Josilda R.S.; Mello, Claudio L.; Carmo, Isabela O.; Kowata, Emilia A.; Yee, Marcio; Brito, Silvio Luiz M.; Gozzi, Giuiliano; Kassab, Luciana R.P

    2003-05-01

    Opticallly stimulated luminescence (OSL) dating has been applied to a wide variety of materials such as loess, sand dunes, colluvium, alluvium, volcanic products, etc., helping geologic geomorphologic studies. OSL dating results using feldspar crystals extracted from alluvial and colluvial deposits of SE Brazilian Plateau will be presented in this work. The methodology used is based on the regeneration method, with multiple aliquot protocol. A total of 23 sample ages were obtained spanning 6.5-97.2 kyr. Results of radioactive contents and comparison with radiocarbon ages will be discussed.

  17. Alluvial fan response to climatic change: Insights from numerical modeling (Invited)

    Science.gov (United States)

    Pelletier, J. D.

    2009-12-01

    Alluvial fans in the western U.S. exhibit a regionally correlative sequence of Plio-Quaternary deposits. Cosmogenic and U-series dating has greatly improved the age control on these deposits and their associated terraces and generally strengthened the case for aggradation during humid-to-arid transitions. Still, the linkages between climate change, upland basin response, and alluvial fan response are not well constrained. Fans may fill and cut as a result of autogenetic processes/internal adjustments, changes in regional temperature (which controls snowmelt-induced flooding), changes in the frequency-size distribution of rainfall events, and/or changes in upslope vegetation. Here I describe the results of a numerical modeling study designed to better constrain the relationships between different end-member forcing mechanisms and the geologic record of alluvial fan deposits and terraces. The model solves the evolution of the fan topography using Exner's equation (conservation of mass) coupled with a nonlinear, threshold-controlled transport relation for sand and gravel. Bank retreat is modeled using an advection equation with a rate proportional to bank shear stress. I begin by considering the building of a fan under conditions of constant water and sediment supply. This simple system exhibits all of the complexity of fans developed under experimental conditions, and it provides insights into the mechanisms that control avulsions and it provides a baseline estimate for the within-fan relief that can result from autogenetic processes. Relationships between the magnitude and period of variations in the sediment-to-water ratio and the geomorphic response of fans are then discussed. I also consider the response of a coupled drainage basin-fan system to changes in climate, including the hydrologic and vegetation response of upland hillslopes. Fans can aggrade or incise in response to the same climatic event depending on the relief of the upstream drainage basin, which

  18. Modeling flow and sediment transport dynamics in the lowermost Mississippi River, Louisiana, USA, with an upstream alluvial-bedrock transition and a downstream bedrock-alluvial transition: Implications for land building using engineered diversions

    Science.gov (United States)

    Viparelli, Enrica; Nittrouer, Jeffrey A.; Parker, Gary

    2015-03-01

    The lowermost Mississippi River, defined herein as the river segment downstream of the Old River Control Structure and hydrodynamically influenced by the Gulf of Mexico, extends for approximately 500 km. This segment includes a bedrock (or more precisely, mixed bedrock-alluvial) reach that is bounded by an upstream alluvial-bedrock transition and a downstream bedrock-alluvial transition. Here we present a one-dimensional mathematical formulation for the long-term evolution of lowland rivers that is able to reproduce the morphodynamics of both the alluvial-bedrock and the bedrock-alluvial transitions. Model results show that the magnitude of the alluvial equilibrium bed slope relative to the bedrock surface slope and the depth of bedrock surface relative to the water surface base level strongly influence the mobile bed equilibrium of low-sloping river channels. Using data from the lowermost Mississippi River, the model is zeroed and validated at field scale by comparing the numerical results with field measurements. The model is then applied to predict the influence on the stability of channel bed elevation in response to delta restoration projects. In particular, the response of the river bed to the implementation of two examples of land-building diversions to extract water and sediment from the main channel is studied. In this regard, our model results show that engineered land-building diversions along the lowermost Mississippi River are capable of producing equilibrated bed profiles with only modest shoaling or erosion, and therefore, such diversions are a sustainable strategy for mitigating land loss within the Mississippi River Delta.

  19. A participatory approach of flood vulnerability assessment in the Banat Plain, Romania

    Science.gov (United States)

    Balteanu, Dan; Costache, Andra; Sima, Mihaela; Dumitrascu, Monica; Dragota, Carmen; Grigorescu, Ines

    2014-05-01

    The Banat Plain (western Romania) is a low, alluvial plain affected by neotectonic subsidence movements, being a critical region in terms of exposure to floods. The latest extreme event was the historic floods occcured in the spring of 2005, which caused significant economic damage in several rural communities. The response to 2005 floods has highlighted a number of weaknesses in the management of hazards, such as the deficiencies of the early warning system, people awareness or the inefficiency of some mitigation measures, besides the past structural measures which are obsolete. For a better understanding of the local context of vulnerability and communities resilience to floods, the quantitative assessment of human vulnerability to floods was supplemented with a participatory research, in which there were involved five rural settlements from the Banat Plain (comprising 15 villages and a population of over 12,000 inhabitants). Thus, in the spring of 2013, a questionnaire-based survey was conducted in approx. 100 households of the affected communities and structured interviews were held with local authorities, in the framework of VULMIN project, funded by the Ministry of National Education. The questionnaire was designed based on a pilot survey conducted in 2005, several months after the flood, and was focused on two major issues: a) perception of the local context of vulnerability to environmental change and extreme events; b) perception of human vulnerability to floods (personal experience, post-disaster rehabilitation, awareness, worrying and opinion on the measures aimed to prevent and mitigate the effects of flooding). The results were correlated with a number of specific variables of the households included in the sample, such as: household structure; income source; income level; location of the dwelling in relation to floodplains. In this way, we were able to draw general conclusions about the way in which local people perceive the extreme events, such as

  20. Effect of heterogeneity on radionuclide retardation in the alluvial aquifer near Yucca Mountain, Nevada.

    Science.gov (United States)

    Painter, S; Cvetkovic, V; Turner, D R

    2001-01-01

    The U.S. Department of Energy is currently studying Yucca Mountain, Nevada, as a potential site for a geological high-level waste repository. In the current conceptual models of radionuclide transport at Yucca Mountain, part of the transport path to pumping locations would be through an alluvial aquifer. Interactions with minerals in the alluvium are expected to retard the downstream migration of radionuclides, thereby delaying arrival times and reducing ground water concentrations. We evaluate the effectiveness of the alluvial aquifer as a transport barrier using the stochastic Lagrangian framework. A transport model is developed to account for physical and chemical heterogeneities and rate-limited mass transfer between mobile and immobile zones. The latter process is caused by small-scale heterogeneity and is thought to control the macroscopic-scale retardation in some field experiments. A geostatistical model for the spatially varying sorption parameters is developed from a site-specific database created from hydrochemical measurements and a calibrated modeling approach (Turner and Pabalan 1999). Transport of neptunium is considered as an example. The results are sensitive to the rate of transfer between mobile and immobile zones, and to spatial variability in the hydraulic conductivity. Chemical heterogeneity has only a small effect, as does correlation between hydraulic conductivity and the neptunium distribution coefficient. These results illustrate how general sensitivities can be explored with modest effort within the Lagrangian framework. Such studies complement and guide the application of more detailed numerical simulations.

  1. The preliminary study on the alluvial stratigraphy of Peinan archaeological site, Taiwan

    Science.gov (United States)

    Yang, Hsiaochin; Chen, Wenshan; Yeh, Changkeng

    2015-04-01

    Many of the activities of prehistoric people who lived in Taiwan were concentrated around river terrace environments and seldom in alluvial environments which are resulting from the rapid tectonic uplift and high erosion rate of the late Cenozoic mountain belt. However, the Peinan archaeological site, one of the most important Neolithic sites in Taiwan because of the great amount of slate slab coffins and nephrite artifacts unearthed, is located at the bottom of Peinan Hill which is formed by the activity of Lichi and Luyeh Faults. According to the radioactive carbon dating results, the Peinan alluvial fan used as cemetery was lasted over 3,700 years (5700-2000 yr BP) but the related cultural formation was only lasted 400 years (3500-3100 yr BP). What have happened to the prehistoric people? As the stratigraphic record allows archaeologists to ascertain the effects of geological processes on the preservation of the archaeological record, determining which parts of the archaeological records are absent, which have potentially been preserved, and how fragmentary are the preserved portions of the records. The limitations that geologic processes impose on the archaeological record must be recognized and understood before meaningful interpretations of prehistory can be made. Therefore, the reconstruction of the landscape and stratigraphic records in archaeological site not only provides the paleo-environmental context but also helps to explain changes that occurred to human cultures over time.

  2. Quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding

    Science.gov (United States)

    Parsons, D. R.; Simmons, S.; Best, J.

    2010-12-01

    Multibeam Echo-Sounder systems have developed rapidly over recent decades and are routinely deployed to provide high-resolution bathymetric details in range of aquatic environments. Modern data handling and storage technologies now facilitate the logging of the raw acoustic back-scatter information that was previously discarded by these systems. This paper describes methodologies that exploit this logging capability to quantify the concentration and dynamics of suspended sediment within the water column and presents a novel method that also allows for quantification of 2D flow velocities. This development provides a multi-purpose tool for the holistic surveying of the process linkages between flow, sediment transport and bed morphology. The application of this new technique is illustrated with reference to flow over alluvial sand dunes, which allows, for the first time in a field study, quantitative visualization of larg-scale, whole flow field, turbulent coherent flow structures, associated with the dune leeside, that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows. CFS captured by MBES in the lee of an alluvial dune. Contours of suspended sediment concentration and superimposed 2D flow velocity vectors

  3. The impact of medium architecture of alluvial settings on non-Fickian transport

    Science.gov (United States)

    Zhang, Yong; Green, Christopher T.; Fogg, Graham E.

    2013-01-01

    The influence of heterogeneous architecture of alluvial aquifers on non-Fickian transport is explored using the Monte Carlo approach. More than two thousand high-resolution hydrofacies models representing seven groups of alluvial settings are built to test the effects of varying facies proportions, mean length and its anisotropy ratio, juxtapositional tendencies, and sub-facies heterogeneity. Results show that the volumetric fraction (P(Z)) of floodplain layers classified by their thicknesses Z controls the non-Fickian tailing of tracer transport at late times. A simple quantitative relationship SBTC≈SP(Z)/2-1 is built based on a multi-rate mass transfer analysis, where SBTC is the slope of the power-law portion of tracer breakthrough curve, and SP(Z) denotes the slope of the power-law portion of the distribution of P(Z) which can be measured, e.g., in core logs. At early times, the mean length of hydrofacies affects the non-Fickian tailing by controlling the channeling of flow in high-permeability non-floodplain materials and the sequestration in surrounding low-permeability floodplain layers. The competition between channeling and sequestration generates complex pre-asymptotic features, including sublinear growth of plume mean displacement, superlinear growth of plume variance, and skewed mass distribution. Those observations of the influence of medium heterogeneity on tracer transport at early and late times may lead to development of nonlocal transport models that can be parameterized using measurable aquifer characteristics.

  4. Object-based forest classification to facilitate landscape-scale conservation in the Mississippi Alluvial Valley

    Science.gov (United States)

    Mitchell, Michael; Wilson, R. Randy; Twedt, Daniel J.; Mini, Anne E.; James, J. Dale

    2016-01-01

    The Mississippi Alluvial Valley is a floodplain along the southern extent of the Mississippi River extending from southern Missouri to the Gulf of Mexico. This area once encompassed nearly 10 million ha of floodplain forests, most of which has been converted to agriculture over the past two centuries. Conservation programs in this region revolve around protection of existing forest and reforestation of converted lands. Therefore, an accurate and up to date classification of forest cover is essential for conservation planning, including efforts that prioritize areas for conservation activities. We used object-based image analysis with Random Forest classification to quickly and accurately classify forest cover. We used Landsat band, band ratio, and band index statistics to identify and define similar objects as our training sets instead of selecting individual training points. This provided a single rule-set that was used to classify each of the 11 Landsat 5 Thematic Mapper scenes that encompassed the Mississippi Alluvial Valley. We classified 3,307,910±85,344 ha (32% of this region) as forest. Our overall classification accuracy was 96.9% with Kappa statistic of 0.96. Because this method of forest classification is rapid and accurate, assessment of forest cover can be regularly updated and progress toward forest habitat goals identified in conservation plans can be periodically evaluated.

  5. Fe and Mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kangjoo [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of)], E-mail: kangjoo@kunsan.ac.kr; Kim, Hyun-Jung; Choi, Byoung-Young; Kim, Seok-Hwi; Park, Ki-hoon [School of Civil and Environmental Engineering, Kunsan National University, Jeonbuk 573-701 (Korea, Republic of); Park, Eungyu [Department of Geology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Koh, Dong-Chan [Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Yun, Seong-Taek [Department of Earth and Environmental Sciences, Korea University, Seoul 136-701 (Korea, Republic of)

    2008-01-15

    Iron and Mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low SO{sub 4} concentrations. The mass balance and isotopic approaches of this study demonstrate that reduction of SO{sub 4}, supplied from agricultural activities such as fertilization and irrigation, is important in lowering Fe and Mn levels in alluvial groundwaters underneath a paddy field. This study was performed to investigate the processes regulating Fe and Mn levels in groundwaters of a point bar area, which has been intensively used for flood cultivation. Four multilevel-groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry. The results show that Fe and Mn levels are regulated by the presence of NO{sub 3} at shallow depths and by SO{sub 4} reduction at the greater depths. Isotopic and mass balance analyses revealed that NO{sub 3} and SO{sub 4} in groundwater are mostly supplied from the paddy field, suggesting that the Fe-and Mn-rich zone of the study area is confined by the agricultural activities. For this reason, the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of Fe/Mn-rich groundwaters in the paddy field area.

  6. Well-balanced numerical modelling of non-uniform sediment transport in alluvial rivers

    Institute of Scientific and Technical Information of China (English)

    Honglu Qian; Zhixian Cao; Gareth Pender; Huaihan Liu; Peng Hu

    2015-01-01

    abstract The last two decades have witnessed the development and application of well-balanced numerical models for shallow flows in natural rivers. However, until now there have been no such models for flows with non-uniform sediment transport. This paper presents a 1D well-balanced model to simulate flows and non-capacity transport of non-uniform sediment in alluvial rivers. The active layer formulation is adopted to resolve the change of bed sediment composition. In the framework of the finite volume Slope LImiter Centred (SLIC) scheme, a surface gradient method is incorporated to attain well-balanced solutions to the governing equations. The proposed model is tested against typical cases with irregular topography, including the refilling of dredged trenches, aggradation due to sediment overloading and flood flow due to landslide dam failure. The agreement between the computed results and measured data is encouraging. Compared to a non-well-balanced model, the well-balanced model features improved performance in reproducing stage, velocity and bed deformation. It should find general applications for non-uniform sediment transport modelling in alluvial rivers, especially in mountain areas where the bed topography is mostly irregular.

  7. Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman

    Science.gov (United States)

    Blechschmidt, Ingo; Matter, Albert; Preusser, Frank; Rieke-Zapp, Dirk

    2009-09-01

    A vast bajada consisting of coalescing low-gradient (veneer of weakly cemented Quaternary gravels. A combination of remote sensing, lithological analyses and luminescence dating is used to interpret the complex aggradation history of the Quaternary alluvial fans from the interior of Oman in the context of independent regional climate records. From satellite imagery and clast analysis four fans can be discerned in the study area. While two early periods of fan formation are tentatively correlated to the Miocene-Pliocene and the Early Pleistocene, luminescence dating allows the distinction of five phases of fan aggradation during the Middle-Late Pleistocene. These phases are correlated with pluvial periods from Marine Isotope Stage (MIS) 11 through 3, when southern Arabia was affected by monsoonal precipitation. It is concluded that the aggradation of the alluvial fans was triggered by the interplay of increased sediment production during arid periods and high rainfall with enhanced erosion of hillslopes and transport rates during strong monsoon phases. However, the lack of fine-grained sediments, bioturbation and organic material implies that although the Quaternary fans are sourced by monsoonal rains they formed in a semi-arid environment. Thus, it appears that, in contrast to the Oman Mountains, the interior was not directly affected by monsoonal precipitation.

  8. Heat tracer test in an alluvial aquifer: field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Nguyen, Frederic; Brouyère, Serge; Dassargues, Alain

    2016-04-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in monitoring wells. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells distributed throughout the field site (space-filling arrangement) were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume was explained by the groundwater flow gradient on the site and heterogeneity of hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with the pilot point inverse approach, main preferential flow paths were delineated.

  9. Resonance analysis of a 2D alluvial valley subjected to seismic waves.

    Science.gov (United States)

    Chai, Juin-Fu; Teng, Tsung-Jen; Yeh, Chau-Shioung; Shyu, Wen-Shinn

    2002-08-01

    The T-matrix formalism and an ultrasonic experiment are developed to study the scattering of in-plane waves for an alluvial valley embedded in a two-dimensional half-space. The solution of the in-plane scattering problem can be determined by the T-matrix method, where the basis functions are defined by the singular solutions of Lamb's problems with surface loading in both horizontal and vertical directions. In the experiment, a thin steel plate with a semicircular aluminum plate attached on the edge is used to simulate the two-dimensional alluvial valley in the state of plane stress. Based on the spectra of displacement signals measured at the free edge of the scatterer, the resonance frequencies where the peaks appear can be identified. It can be shown that the nondimensional resonance frequency is one of the characteristic properties of the scattering system. Furthermore, it is noted that the nondimensional resonance frequencies measured experimentally are in good agreement with those calculated theoretically.

  10. Reconstructing the Geomorphological Evolution of the Plain of Xanthos (SW Turkey) during the Holocene : a Geoarchaeological Approach

    Science.gov (United States)

    Ecochard, E.; Fouache, E.; Kuzucuoǧlu, C.; Carcaud, N.; Ekmekçi, M.; Ulusoy, I.; Robert, V.; Çiner, A.; Des Courtils, J.

    2009-04-01

    In the Hellenistic period, according to Strabo, Xanthos and Letoon were very important cities and major holy places in Lycia, a peninsula in southwestern contemporary Turkey. An archaeological study of the sites of Xanthos and Letoon cannot assume that the environment in which they are located did not change since the arrival of the first settlers in the seventh century BC. The rise of the sea level in the last 15,000 years and the subsequent Holocene alluviation has a strong impact on the landscape. The river Esen Çayı meandered in the valley leaving alluvial deposits, and the slopes were eroded. The geography of the valley of the river Esen Çayı during the Lycian and Hellenistic periods, i.e. during the 1st millennium BC, yet remains significantly unknown. What was the landscape around the Letoon shrine like? Where were the river channels? What was the progradation stage of the deltaic plain? To what extent did the slope mobility determine the location of settlements and ancient roads? To answer these questions, geomorphological dynamics at work throughout the Holocene must be reconstructed. In this communication, preliminary results from the analysis of cores and geophysical profiles, both performed during and after four field work seasons in the plain, are compared with the historical, archaeological and literary data, and a first reconstruction of the changing landscape is proposed. The sedimentary records indicate that a marine bay was gradually closed by the development of coastal sand deposits, prompting the development of a lagoonal system. As lagoons and wetlands have long been dominant in the plain, both sites probably developed in this type of landscape. In front of the Letoon site, a channel of the river Esen Çayı has been identified. It probably allowed for a direct connection by boat between the holy place and the sea downstream, and with the city of Xanthos upstream. This channel was probably responsible of the gradual sinking of the sanctuary

  11. Koroška Bela alluvial fan – The result of the catastrophic slope events; (Karavanke Mountains, NW Slovenia

    Directory of Open Access Journals (Sweden)

    Jernej Jež

    2008-12-01

    Full Text Available The Koroška Bela alluvial fan deposits were investigated to determine the genesis of the fan and the source area of sediments. The alluvial fan is composed of a sequence of diamicton layers, and related subaeric sediments that were deposited by multiple mass flow events, in some cases certainly by debris flows. The predominant sources ofsediments are tectonically deformed clastic and partly carbonate Carbonifferous and Permian rocks. In diamictons also pebbles of other rocks from the hinterland are present. These were eroded from the channel of Bela during the mass flow events. We estimate the future debris flow hazard along Bela stream as high.

  12. Electrical Resistivity Survey for Delineation of the Seawater Intrusion in the Çanakkale Plain, NW Turkey

    Science.gov (United States)

    Demirci, Alper; Ekinci, Yunus Levent; Kaya, Mehmet Ali

    2013-04-01

    The city of Çanakkale (Dardanelles) is located on the west side of the Biga Peninsula. The Peninsula is delimited by the Strait of Çanakkale, which is the unique water linkage between the Aegean Sea and the Marmara Sea. The study area is covered by quaternary aged sediments. Sarıçay, which originates from the eastern hilly area, accumulates sediment deposits and forms this alluvial basin. Alluvial terrace including sand, gravel and block sized materials is observed towards northeastern part of this basin. There has been six-fold increase in the population and tremendous growth in industrial and environmental activities in Çanakkale city in the last two decades. Thus, there has been necessity of new settlement areas for planned urbanization and the parameters of liquefaction potential and the extent of seawater intrusion should be taken into consideration. To this end, we have carried out Direct Current (DC) electrical resistivity survey on 52 stations to shed light on the thickness of alluvial layers and traces of the seawater intrusion in the Çanakkale plain. We have used maximum half current electrode spacing (AB/2) of 80 m for each station. The acquired apparent resistivity data were processed by using a damped least square inversion algorithm with singular value decomposition (SVD) technique. After obtaining the model parameters (thickness and resistivity) of each resistivity curve, a MATLAB-based visualization algorithm was used for joint representation of the whole resistivity variation of the studied area. The produced psuedo-three dimensional volumetric resistivity distribution images indicated that the western part of investigation area has relatively resistive structures (> 80 ohm.m), which extend to the depth of 3 m. The sudden decrease in resistivity values to downward clearly indicated seawater saturated sediments (0.5-5 ohm.m). On contrary to these low resistivity values observed at the western part of the city, the central and eastern parts are

  13. Suitable scale of Weigan River plain oasis

    Institute of Scientific and Technical Information of China (English)

    HU ShunJun; SONG YuDong; TIAN ChangYan; LI YueTan; LI XiuCang; CHEN XiaoBing

    2007-01-01

    Desert coexists with oasis in long time, and the existence and development of oasis system demand better oasis vegetation ecological system. Oasis scale of arid zone plain encircling water should be determined in case of desertification caused by land over-reclamation under the circumstance of water resources shortage. Steady oasis with virtuous circle must have appropriate land use structure for agriculture, forestry and graziery. The study on the suitable scale and developmental space of oasis will provide theoretical and applicable foundation for effective construction of oases. By analyzing the hydrothermal, water and soil balance, an optimal mathematical model has been established. Based on hydrometeorology data collected for years in Weigan River plain, and by the principle of water balance,a calculation has been made of the water resources for evapotranspiration and the optimal acreage of oasis and cultivated land, which shows that the water resources for evapotranspiration in the Weigan River plain oasis is 22.32×108 m3 and the optimal oasis acreage under the condition of conventional irrigation mode is 3716.06 km2, in which the suitable cultivated land acreage is 1564.79 km2. Under the condition of water-saving irrigation, the suitable oasis acreage is 5515.49 km2, in which the suitable cultivated land acreage is 2322.31 km2. The oasis area had reached 4123 km2, and the cultivated land acreage had reached 1507 km2 after the Agriculture Irrigation Drainage Water Project of World Bank Loan in Weigan River basin was finished in 1997. The oasis and cultivated land acreage will be more suitable, and the oasis scale can be enlarged moderately by means of water saving irrigation.

  14. Medicine Wheels of the Great Plains

    Science.gov (United States)

    Vogt, David

    Medicine Wheels are unexplained aboriginal boulder configurations found primarily on hilltops and river valley vistas across the northwest Great Plains of North America. Their varied, complex designs have inspired diverse hypotheses concerning their meaning and purpose, including astronomical ones. While initial "observatory" speculations were unfounded, and quests to "decode" these structures remain unfulfilled and possibly misguided, the Medicine Wheels nevertheless represent a uniquely worthwhile case study in archaeoastronomical theory and method. In addition, emerging technologies for data acquisition and analysis pertinent to Medicine Wheels offer prospectively important new sight lines for the future of archaeoastronomy.

  15. Improving Web Page Readability by Plain Language

    CERN Document Server

    Hussain, Walayat; Ali, Arif

    2011-01-01

    In today's world anybody who wants to access any information the first choice is to use the web because it is the only source to provide easy and instant access to information. However web readers face many hurdles from web which includes load of web pages, text size, finding related information, spelling and grammar etc. However understanding of web pages written in English language creates great problems for non native readers who have basic knowledge of English. In this paper, we propose a plain language for a local language (Urdu) using English alphabets for web pages in Pakistan. For this purpose we developed two websites, one with a normal English fonts and other in a local language text scheme using English alphabets. We also conducted a questionnaire from 40 different users with a different level of English language fluency in Pakistan to gain the evidence of the practicality of our approach. The result shows that the proposed plain language text scheme using English alphabets improved the reading com...

  16. Improving Web Page Readability by Plain Language

    Directory of Open Access Journals (Sweden)

    Walayat Hussain

    2011-05-01

    Full Text Available In todays world anybody who wants to access any information the first choice is to use the web because it is the only source to provide easy and instant access to information. However web readers face many hurdles from web which includes load of web pages, text size, finding related information, spelling and grammar etc. However understanding of web pages written in English language creates great problems for non native readers who have basic knowledge of English. In this paper, we propose a plain language for a local language (Urdu using English alphabets for web pages in Pakistan. For this purpose we developed two websites, one with a normal English fonts and other in a local language text scheme using English alphabets. We also conducted a questionnaire from 40 different users with a different level of English language fluency in Pakistan to gain the evidence of the practicality of our approach. The result shows that the proposed plain language text scheme using English alphabets improved the reading comprehension for non native English speakers in Pakistan.

  17. Creep of plain weave polymer matrix composites

    Science.gov (United States)

    Gupta, Abhishek

    Polymer matrix composites are increasingly used in various industrial sectors to reduce structural weight and improve performance. Woven (also known as textile) composites are one class of polymer matrix composites with increasing market share mostly due to their lightweight, their flexibility to form into desired shape, their mechanical properties and toughness. Due to the viscoelasticity of the polymer matrix, time-dependent degradation in modulus (creep) and strength (creep rupture) are two of the major mechanical properties required by engineers to design a structure reliably when using these materials. Unfortunately, creep and creep rupture of woven composites have received little attention by the research community and thus, there is a dire need to generate additional knowledge and prediction models, given the increasing market share of woven composites in load bearing structural applications. Currently, available creep models are limited in scope and have not been validated for any loading orientation and time period beyond the experimental time window. In this thesis, an analytical creep model, namely the Modified Equivalent Laminate Model (MELM), was developed to predict tensile creep of plain weave composites for any orientation of the load with respect to the orientation of the fill and warp fibers, using creep of unidirectional composites. The ability of the model to predict creep for any orientation of the load is a "first" in this area. The model was validated using an extensive experimental involving the tensile creep of plain weave composites under varying loading orientation and service conditions. Plain weave epoxy (F263)/ carbon fiber (T300) composite, currently used in aerospace applications, was procured as fabrics from Hexcel Corporation. Creep tests were conducted under two loading conditions: on-axis loading (0°) and off-axis loading (45°). Constant load creep, in the temperature range of 80-240°C and stress range of 1-70% UTS of the

  18. Climate change and Sea level rise: Potential impact on the coast of the Edremit Plain, NW Turkey.

    Science.gov (United States)

    Curebal, Isa; Efe, Recep; Soykan, Abdullah; Sonmez, Suleyman

    2015-04-01

    Over the past century, most of the world's mountain glaciers and the ice sheets have lost mass due to global warming. When the temperature exceeds a particular level, glaciers and polar ice caps will continue to lose mass. Recent studies report that low-lying coastal areas will be seriously affected by sea level rise. Changes in the amount of natural and anthropogenic greenhouse gases and aerosols had a warming effect on the global climate during last century. Thus, the pace of melting of ice sheets increased, and, accordingly, sea level began to rise faster. Rise in sea level between 1961 and 2003 was equal to 1.8 mm/year while it was 3.1 mm/year between 1993 and 2003. The total rise in the 20th century is estimated to be between 17 and 19 cm. The models based on the sea level change indicate that the average global temperature at the end of the 21st century will increase by 0.3°C - 6.4°C. Global sea level is projected to rise 8-25 cm by 2030, relative to 2000 levels, 18-48 cm by 2050, and 50-140 cm by 20110. The Edremit Plain lies between Mount Madra and the Kaz Mountains on the coast of Aegean Sea in NW Turkey. It is lowland with an area of 141 km2. The widest part of the plain is 16 km along the E - W direction. The N - S direction amounts to a width of 15 km. The plain is covered with alluvial deposits that settled in the Quaternary Period. The elevation ranges from 0 to 50 m a.s.l. in the plain. This study aims to determine how the low-lying coastal land areas of the Edremit Plain may be affected by possible changes in sea level. Elevation dataset is based on the digital elevation model (DEM) of Landsat ETM + satellite images. To that end, satellite images were used to draw the current coastline. Curves of 2.5, 5, and 10 m were drawn through the use of maps with a scale of 1/25.000. Later on, the areas of the fields between these points were calculated. Current estimates show that 2.5 m rise in sea level will cause sea water to cover an area of 8.6 km2 (%14

  19. Experimental and numerical findings on the long-term evolution of migrating alternate bars in alluvial channels

    NARCIS (Netherlands)

    Crosato, A.; Desta, F.B.; Cornelisse, J.; Schuurman, F.; Uijttewaal, W.S.J.

    2012-01-01

    Migrating alternate bars form in alluvial channels as a result of morphodynamic instability. Extensive literature can be found on their origin and short-term development, but their long-term evolution has been poorly studied so far. In particular, it is not clear whether migrating bars eventually re

  20. Electrical Resistivity Tomography and Induced Polarization for Mapping the Subsurface of Alluvial Fans: A Case Study in Punata (Bolivia

    Directory of Open Access Journals (Sweden)

    Andres Gonzales Amaya

    2016-11-01

    Full Text Available Conceptual models of aquifer systems can be refined and complemented with geophysical data, and they can assist in understanding hydrogeological properties such as groundwater storage capacity. This research attempts to use geoelectrical methods, Electrical Resistivity Tomography and Induced Polarization parameters, for mapping the subsurface in alluvial fans and to demonstrate its applicability; the Punata alluvial fan was used as a case study. The resistivity measurements proved to be a good tool for mapping the subsurface in the fan, especially when used in combination with Induced Polarization parameters (i.e., Normalized Chargeability. The Punata alluvial fan characterization indicated that the top part of the subsurface is composed of boulders in a matrix of finer particles and that the grain size decreases with depth; the electrical resistivity of these deposits ranged from 200 to 1000 Ωm, while the values of normalized chargeability were lower than 0.05 mS/m. The bottom of the aquifer system consisted of a layer with high clay content, and the resistivity ranged from 10 to 100 Ωm, while the normalized chargeability is higher than 0.07 mS/m. With the integration of these results and lithological information, a refined conceptual model is proposed; this model gives a more detailed description of the local aquifer system. It can be concluded that geoelectrical methods are useful for mapping aquifer systems in alluvial fans.

  1. Evaluating the controls of shear stress, sediment supply, alluvial cover, and channel morphology on experimental bedrock incision rate

    Science.gov (United States)

    Johnson, Joel P. L.; Whipple, Kelin X.

    2010-06-01

    We explored the dependence of experimental bedrock erosion rate on shear stress, bed load sediment flux, alluvial bed cover, and evolving channel morphology. We isolated these variables experimentally by systematically varying gravel sediment flux Qs and water discharge Qw in a laboratory flume, gradually abrading weak concrete "bedrock." All else held constant, we found that (1) erosion rate was insensitive to flume-averaged shear stress, (2) erosion rate increased linearly with sediment flux, (3) erosion rate decreased linearly with the extent of alluvial bed cover, and (4) the spatial distribution of bed cover was sensitive to local bed topography, but the extent of cover increased with Qs/Qt (where Qt is flume-averaged transport capacity) once critical values of bed roughness and sediment flux were exceeded. Starting from a planar geometry, erosion increased bed roughness due to feedbacks between preferential sediment transport through interconnected topographic lows, focused erosion along these zones of preferential bed load transport, and local shear stresses that depended on the evolving bed morphology. Finally, continued growth of bed roughness was inhibited by imposed variability in discharge and sediment flux, due to changes in spatial patterns of alluvial deposition and impact wear. Erosion was preferentially focused at lower bed elevations when the bed was cover-free, but was focused at higher bed elevations when static alluvial cover filled topographic lows. Natural variations in discharge and sediment flux may thus stabilize and limit the growth of roughness in bedrock channels due to the effects of partial bed cover.

  2. The Temporal-Spatial Distribution of Shule River Alluvial Fan Units in China Based on SAR Data and OSL Dating

    Directory of Open Access Journals (Sweden)

    Lu Zhang

    2013-12-01

    Full Text Available Alluvial fans in arid and semi-arid regions can provide important evidence of geomorphic and climatic changes, which reveal the evolution of the regional tectonic activity and environment. Synthetic aperture radar (SAR remote sensing technology, which is sensitive to geomorphic features, plays an important role in quickly mapping alluvial fan units of different ages. In this paper, RADARSAT-2 (Canada’s C-band new-generation radar satellite and ALOS-PALSAR (Japan’s advanced land observing satellite, phased array type L-band SAR sensor data, acquired over the Shule River Alluvial Fan (SRAF, are used to extract backscattering coefficients, scattering mechanism-related information, and polarimetric characteristic parameters. The correlation between these SAR characteristic parameters and fan units of the SRAF of different ages was studied, and the spatial distribution of fan units, since the Late Pleistocene, was extracted based on the Maximum Likelihood classification method. The results prove that (1 some C-band SAR parameters can describe the geomorphic characteristics of alluvial fan units of different ages in the SRAF; (2 SAR data can be used to map the SRAF’s surface between the Late Pleistocene and the Holocene and to extract the spatial distribution of fan units; and (3 the time-spatial distribution of the SRAF can provide valuable information for tectonic and paleoenvironmental research of the study area.

  3. Weeds of cereal stubble-fields on various soils in the Kielce region. P. III. Black, alluvial and rendzina soils

    Directory of Open Access Journals (Sweden)

    Maria Jędruszczak

    2013-12-01

    Full Text Available The weed flora growing stubble-fields area is determined by soil features. Weeds found in cereal stubble-fields on black soils formed from sands and loams, medium and haevy alluvial soils as well as brown and chernozem rendzina soils are presented in the paper. The 273 phytosociological records were worked out. They were collected from 87 stands situated in 76 localities of Kielce region. The results showed that species number and species composition were dependent on the soils (black. alluvial, rendzina. The existance of 118 (medium alluvial soil to 140 (brown rendzina soil weed species, including 73 common for all of the soils considered, was found there. Relatively high per cent (29-35 of them belonged to perennial weeds. From 22 (brown rendzina soil to 35 (heavy alluvial soil of species reached high constancy degrees (V-III. Stellaria media, Myosotis arvensis, Polygonum aviculare, Agropyron repens and Cirsium arvense predominated on the all of the soil examined. Among the weed flora registered, 25 species, recorded only on rendzina soils, were distinguishable for that soils.

  4. Geophysical and Hydrological Characterization of Alluvial Fans in the Valle El Sauz Encinillas, Chihuahua, México.

    Science.gov (United States)

    Villalobos-Aragón, A.; Chávez-Aguirre, R.; Osuna-Vizcarra, A.; Espejel-García, V. V.

    2007-05-01

    The Valle El Sauz Encinillas (VESE) is located 92 km north of Chihuahua City, México. Despite being the principal aquifer feeding Chihuahua City, and being flanked by two well studied geological features (Bloque Calera-Del Nido to the West, and the Sierra Peña Blanca to the East), a lack of available hydrogeological data prevails in the valley. The goals of this study are two: 1) geomorphometrical analysis of the sub-basins and alluvial fans, and 2) determination of the alluvial fan geoelectrical units via electrical-resistivity soundings. The Basin and Range system forms a closed sub-basin with a lacustrine basin system in extinction process. The aquifer is located in alluvial Quaternary sediments, with varying granulometry, reaching a thickness of 600 meters at the center of the valley. The biggest alluvial fan in the VESE is located at the Cañón de Santa Clara, and intersects the playa-lake deposits of the Laguna de Encinillas. This fan has a surface of 73.2 km2 and an average slope of 0.437°. The geomorphometrical analysis included the sub-basins, currents, and the fans in the area. These analyses allow a comparison between alluvial fans in the VESE and those in Death Valley, California, USA. The alluvial fans in both areas show a similar behavior in all plots. Twenty electrical resistivity soundings (Schlumberger array, AB/2 distance of 400 m) were performed in the alluvial fan. The basement and four other geoelectrical units were identified in the fan. The geophysical data, granulometric determinations, plus geochemical information of twelve wells in the area were analyzed. These data show how the decrease in granulometry, both frontally and laterally in the fan, results in a rise of the hydraulic conductivity and transmisivity values (water wells in Los Sauces and El Faro). However, both the permeability and the water quality in its distal portion, are affected by the playa lake deposits, the raising ratio of clay-size sediments (and evaporites) in the

  5. Digital model of the Bates Creek alluvial aquifer near Casper, Wyoming

    Science.gov (United States)

    Glover, K.C.

    1982-01-01

    A digital model was used to simulate ground-water flow within the Bates Creek alluvial aquifer, southwest of Casper, Wyoming. Hydrologic data collected during 1977 and 1978 were used to develop the flow model under steady-state and transient conditions. Three scenarios for operating the stream-aquifer system were evaluated with the digital model. The scenarios represent no ground-water pumping, pumping by all existing wells , and pumping by all existing and proposed wells. The model simulations used average values of stream discharge, ground-water pumpage and water use as input parameters. A decrease in the quantitity of ground-water discharge to Bates Creek is predicted to occur through 1988 as a result of pumping. The magnitude and timing of the predicted decrease in ground-water discharge may differ from actual ground-water discharge if hydrologic conditions through 1988 vary significantly from the averaged input values used in the simulations. (USGS)

  6. Soil mycoflora of banana and cassava in peatland and alluvial soil in Bengkulu

    Directory of Open Access Journals (Sweden)

    SUCIATMIH

    2006-10-01

    Full Text Available In order to discover the diversity and population of soil fungi, a study was carried out at banana (Musa paradisiaca and cassava (Manihot utilissima plants where both those plants planted in peatland and alluvial soil. Soil fungi were isolated using serial dilution plate method and they were incubated at both room temperature (27-28oC and 45oC. This process was replicated two times for each sample. The result indicated that from 4 soil samples, 24 genera of fungi representing 4 Ascomycotina, 15 Deuteromycotina, and 5 Zygomycotina were detected. The highest soil fungi population was found in cassava planted in peat land and incubated at room temperature (8.5 105 cfu/ g dry soil, while the lower soil fungi population came from banana plant that was planted in peat land and incubated at 45oC (7.1 103 cfu/g dry soil.

  7. Sex Determination of Carolina Wrens (Thryothorus ludovicianus) in the Mississippi Alluvial Valley

    Science.gov (United States)

    Twedt, D.J.

    2004-01-01

    I identified sexual dimorphism in wing length (unflattened chord) of Carolina Wrens (Thryothorus ludovicianus) within the central Mississippi Alluvial Valley (northeast Louisiana and west-central Mississippi) and used this difference to assign a sex to captured wrens. Wrens were identified as female when wing length was less than 57.5 mm or male when wing length was greater than 58.5 mm. Verification of predicted sex was obtained from recaptures of banded individuals where sex was ascertained from the presence of a cloacal protuberance or brood patch. Correct prediction of sex was 81% for adult females and 95% for adult males. An alternative model, which categorized wrens with wing lengths of 58 and 59 mm as birds of unknown sex, increased correct prediction of females to 93% but reduced the number of individuals to which sex was assigned. These simple, predictive, wing-length-based models also correctly assigned sex for more than 88% of young (hatching-year) birds.

  8. Cosmogenic helium and volatile-rich fluid in Sierra Leone alluvial diamonds

    Science.gov (United States)

    Mcconville, P.; Reynolds, J. H.

    1989-01-01

    Noble gas measurements were carried out on two identical splits of a finely powdered harshly acid-washed sample derived from fragments of a single alluvial diamond from Sierra Leone, with essentially identical results obtained for both splits. Isotopic ratios for Ar, Kr, and Xe were found to be atmospheric. Their elemental abundances were high relative to published data, owing to the effect of shock implantation in the crushing step, as was verified in a supplementary experiment. No Ne was detected above the blank level. The He-3 was exceptionally abundant, while He-4 was exceptionally depleted, possibly due to the acid wash. The He-3/He-4 ratio was anomalously high at an R/Ra value of 246 + or - 16. The results support the hypothesis that the He-3 excess in diamonds is cosmogenic.

  9. Steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system

    Science.gov (United States)

    Brooks, Lynette E.; Masbruch, Melissa D.; Sweetkind, Donald S.; Buto, Susan G.

    2014-01-01

    This report describes the construction, calibration, evaluation, and results of a steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system that was developed as part of the U.S. Geological Survey National Water Census Initiative to evaluate the nation’s groundwater availability. The study area spans 110,000 square miles across five states. The numerical model uses MODFLOW-2005, and incorporates and tests complex hydrogeologic and hydrologic elements of a conceptual understanding of an interconnected groundwater system throughout the region, including mountains, basins, consolidated rocks, and basin fill. The level of discretization in this model has not been previously available throughout the study area.

  10. Fishes in paleochannels of the Lower Mississippi River alluvial valley: A national treasure

    Science.gov (United States)

    Miranda, Leandro E.

    2016-01-01

    Fluvial geomorphology of the alluvial valley of the Lower Mississippi River reveals a fascinating history. A prominent occupant of the valley was the Ohio River, estimated to have flowed 25,000 years ago over western Tennessee and Mississippi to join the Mississippi River north of Baton Rouge, Louisiana, 750–800 km south of the present confluence. Over time, shifts in the Mississippi and Ohio rivers toward their contemporary positions have left a legacy of abandoned paleochannels supportive of unique fish assemblages. Relative to channels abandoned in the last 500 years, paleochannels exhibit harsher environmental conditions characteristic of hypereutrophic lakes and support tolerant fish assemblages. Considering their ecological, geological, and historical importance, coupled with their primordial scenery, the hundreds of paleochannels in the valley represent a national treasure. Altogether, these waterscapes are endangered by human activities and would benefit from the conservation attention afforded to our national parks and wildlife refuges.

  11. Circles of the World: Traditional Art of the Plains Indians.

    Science.gov (United States)

    Conn, Richard

    1985-01-01

    The art of the Plains Indians is discussed, and an art exhibition of their work to be held at the California Academy of Sciences in San Francisco from January 12 to April 29, 1985, is described. The exhibit shows and explains how Plains art served aspects of the Indians' traditional life. (RM)

  12. 49 CFR 215.113 - Defective plain bearing wedge.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Suspension System § 215.113 Defective plain bearing wedge. A railroad may not place or continue in service a car, if a plain bearing wedge on that car is— (a) Missing; (b) Cracked; (c) Broken; or (d) Not...

  13. 49 CFR 215.107 - Defective plain bearing box: General.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Suspension System § 215.107 Defective plain bearing box: General. A railroad may not place or continue in service a car, if the car has— (a) A plain bearing box that does not contain visible free oil; (b) A...

  14. 18 CFR 801.8 - Flood plain management and protection.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Flood plain management... COMMISSION GENERAL POLICIES § 801.8 Flood plain management and protection. (a) Periodic inundation of lands along waterways has not discouraged development of flood hazards areas. Major floods cause loss of...

  15. 27 CFR 9.207 - Outer Coastal Plain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Outer Coastal Plain. 9.207... Outer Coastal Plain. (a) Name. The name of the viticultural area described in this section is “Outer Coastal Plain”. For purposes of part 4 of this chapter, “Outer Coastal Plain” is a term of...

  16. The role of the Wetland Reserve Program in conservation efforts in the Mississippi River Alluvial Valley

    Science.gov (United States)

    King, Sammy L.; Twedt, Daniel J.; Wilson, R. Randy

    2006-01-01

    The Mississippi River Alluvial Valley includes the floodplain of the Mississippi River from Cairo, Illinois, USA, to the Gulf of Mexico. Originally this region supported about 10 million ha of bottomland hardwood forests, but only about 2.8 million ha remain today. Furthermore, most of the remaining bottomland forest is highly fragmented with altered hydrologic processes. During the 1990s landscape-scale conservation planning efforts were initiated for migratory birds and the threatened Louisiana black bear (Ursus americanus luteolus). These plans call for large-scale reforestation and restoration efforts in the region, particularly on private lands. In 1990 the Food, Agriculture, Conservation and Trade Act authorized the Wetlands Reserve Program (WRP). The WRP is a voluntary program administered by the United States Department of Agriculture that provides eligible landowners with financial incentives to restore wetlands and retire marginal farmlands from agricultural production. As of 30 September 2005, over 275,700 ha have been enrolled in the program in the Mississippi River Alluvial Valley, with the greatest concentration in Louisiana, Arkansas, and Mississippi, USA. Hydrologic restoration is common on most sites, with open-water wetlands, such as moist-soil units and sloughs, constituting up to 30% of a given tract. Over 33,200 ha of open-water wetlands have been created, potentially providing over 115,000,000 duck-use days. Twenty-three of 87 forest-bird conservation areas have met or exceed core habitat goals for migratory songbirds and another 24 have met minimum area requirements. The WRP played an integral role in the fulfillment of these goals. Although some landscape goals have been attained, the young age of the program and forest stands, and the lack of monitoring, has limited evaluations of the program's impact on wildlife populations.

  17. THE PERMIAN -TRIASSIC BOUNDARY, DEAD SEA, JORDAN: TRANSITIONAL ALLUVIAL TO MARINE DEPOSITIONAL SEQUENCES AND BIOSTRATIGRAPHY

    Directory of Open Access Journals (Sweden)

    JOHN H. POWELL

    2016-10-01

    Full Text Available The Permian to Triassic transition in Jordan is characterised by a sequence boundary underlain by red-bed, alluvial lithofacies deposited in a humid-tropical climate by low-sinuosity rivers, and overlain by shallow marine siliciclastics with thin carbonates. The low-gradient alluvial floodplain was repeatedly subjected to the development of ferralitic and pisolitic paleosols on the interfluves. In contrast, dysaerobic environments in the fluvial channels and abandoned lakes resulted in the preservation of a prolific flora of macro-plants and palynomorphs that indicate a probable range from Mid- to Late Permian age, though the abundant presence of the distinctive pollen Pretricolpipollenites bharadwajii  indicates the youngest part of that range.  Above the sequence boundary, reddened shallow-marine beds characterised by ripple cross-laminated, siltstones/sandstone with desiccation cracks and sparse surface burrows mark the initial Triassic marine transgression in the region (Arabian Plate Tr 10. These are followed by two thin limestone (packstone beds with shallow scours and bivalve shell lags, that have yielded a low diversity assemblage of conodonts (e.g. Hadrodontina aequabilis and foraminifera (“Cornuspira” mahajeri that are interpreted as euryhaline  taxa characterising the early Induan (Early Triassic. Thus the absence of body fossils and vertical infaunal burrows in the lowest marine beds may reflect low-diversity ecosystems following the Permian-Triassic extinction event, or be a result of stressed shallow marine environments. A gradational upward increase in grey, green and yellow siltstones beds accompanied by a concomitant increase in bioturbation (and infaunal vertical burrows and thin-shelled bivalves about 15 m above the boundary indicates colonisation of the substrate under more normal shallow marine conditions perhaps indicating recovery phase following the extinction event.

  18. Controls on modern tributary-junction alluvial fan occurrence and morphology: High Atlas Mountains, Morocco

    Science.gov (United States)

    Stokes, Martin; Mather, Anne E.

    2015-11-01

    Modern tributary-junction alluvial fans (cone-shaped depositional landforms formed in confined valley settings) were analysed from a 20-km-long reach of the Dades River in the distal part of the fold-thrust belt region in the south-central High Atlas Mountains of Morocco. Here, a deeply dissected network of ephemeral tributary streams and a perennial trunk drainage characterised by an arid mountain desert climate are configured onto a folded and thrust faulted Mesozoic sedimentary sequence. Out of 186 tributary streams, only 29 (16%) generated alluvial fans at their tributary junctions. The fan-generating catchments possess higher relief, longer lengths, lower gradients, and larger areas than nonfan-generating catchments. Whilst geologically, fan-generating catchments are underlain by folded/steeply dipping weak bedrock conducive to high sediment yield. Tributary-junction fans are built from debris flow or fluvial processes into open or confined canyon trunk valley settings. The proximity of the perennial trunk drainage combined with the valley morphology produces lobate or foreshortened trimmed fan forms. Analysis of fan (area, gradient, process), catchment (area, relief, length, gradient), and tributary valley (width) variables reveals weak morphometric relationships, highlighted by residual plots that show dominance of smaller and lower gradient than expected fan forms. These morphometric relationships can be explained by interplay between the catchment and trunk drainage geology, morphology, climate, and flood regime that are combined into a conceptual 'build and reset' model. Ephemeral tributary-junction fans develop progressively during annual localised winter-spring storm events, attempting to build towards a morphological equilibrium. However, the fans never reach an equilibrium morphological form as they are reset by rare (> 10 year) large floods along the River Dades that are linked to regional incursions of Atlantic low pressure troughs. The model

  19. Grain size trends reveal alluvial fan sensitivity to late Pleistocene climate change

    Science.gov (United States)

    Whittaker, A. C.; D'Arcy, M. K.; Roda Boluda, D. C.

    2015-12-01

    The effects of climate change on eroding landscapes and the sedimentary record remain poorly understood. The measurement of grain size fining rates in stream-flow dominated deposits provides one way to address this issue because, in principle, these trends embed important information about the dynamics of sediment routing systems and their sensitivities to external forcing. At a fundamental level, downstream fining is often driven by selective deposition of sediment. The relative efficiency of this process is determined by the physical characteristics of the input sediment supply and the spatial distribution of subsidence rate, which generates the accommodation necessary for mass extraction. Here, we measure grain size fining rates from apex to toe on two alluvial fan systems in northern Death Valley, California, which have well-exposed modern and 70 ka surfaces, where the long-term tectonic boundary conditions are known and where climatic variation over this time period is well-constrained. We integrate a self-similar gravel fraction fining model, based on selective sediment extraction, with cosmogenically-derived catchment erosion rates and gravel fining data, to estimate the change in sediment flux that occurred between 70 ka and the present day. Our results show that a 30 % decrease in average precipitation rate led to a 20 % decrease in sediment flux and a clear increase in the down-fan rate of fining. This supports existing landscape evolution models that relate a decrease in precipitation rate to a decrease in sediment flux, but implies that this relationship may be sub-linear. This study offers a new approach to applying grain size fining models to mountain catchments and their alluvial fan systems, and shows fan stratigraphy can be highly sensitive to climate changes over sensitivity is lost when sediment is remobilised and recycled over a time period longer than the duration of the climatic perturbation.

  20. Bottomland hardwood establishment and avian colonization of reforested sites in the Mississippi Alluvial Valley

    Science.gov (United States)

    Wilson, R.R.; Twedt, D.J.; Fredrickson, L.H.; King, S.L.; Kaminski, R.M.

    2005-01-01

    Reforestation of bottomland hardwood sites in the Mississippi Alluvial Valley has markedly increased in recent years, primarily due to financial incentive programs such as the Wetland Reserve Program, Partners for Wildlife Program, and state and private conservation programs. An avian conservation plan for the Mississippi Alluvial Valley proposes returning a substantial area of cropland to forested wetlands. Understanding how birds colonize reforested sites is important to assess the effectiveness of avian conservation. We evaluated establishment of woody species and assessed bird colonization on 89 reforested sites. These reforested sites were primarily planted with heavy-seeded oaks (Quercus spp.) and pecans (Carya illinoensis). Natural invasion of light-seeded species was expected to diversify these forests for wildlife and sustainable timber harvest. Planted tree species averaged 397 + 36 stems/ha-1, whereas naturally invading trees averaged 1675 + 241 stems/ha. However, naturally invading trees were shorter than planted trees and most natural invasion occurred <100 m from an existing forested edge. Even so, planted trees were relatively slow to develop vertical structure, especially when compared with tree species planted and managed for pulpwood production. Slow development of vertical structure resulted in grassland bird species, particularly dickcissel (Spiza americana) and red-winged blackbird (Agelaius phoeniceus), being the dominant avian colonizers for the first 7 years post-planting. High priority bird species (as defined by Partners in Flight), such as prothonotary warbler (Protonotaria citrea) and wood thrush (Hylocichla mustelina), were not frequently detected until stands were 15 years old. Canonical correspondence analysis revealed tree height had the greatest influence on the bird communities colonizing reforested sites. Because colonization by forest birds is dependent on tree height, we recommend inclusion of at least one fast-growing tree

  1. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Hermans, Thomas; Jamin, Pierre; Orban, Philippe; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-09-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in an injection well and monitoring the evolution of groundwater temperature and tracer concentration in the pumping well and in measurement intervals. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells closely spaced along three transects were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume is explained by the groundwater flow gradient on the site and heterogeneities in the hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with a pilot point approach for inversion of the hydraulic conductivity field, the main preferential flow paths were delineated. The successful application of a field heat tracer test at this site suggests that heat tracer tests is a promising approach to image hydraulic conductivity field. This methodology could be applied in aquifer thermal energy storage (ATES) projects for assessing future efficiency that is strongly linked to the hydraulic conductivity variability in the considered aquifer.

  2. Bicarbonate Impact on U(VI) Bioreduction in a Shallow Alluvial Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Long, Philip E.; Williams, Kenneth H.; Davis, James A.; Fox, Patricia M.; Wilkins, Michael J.; Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.; Berman, Elena S.; Gupta, Manish; Chandler, Darrell P.; Murray, Christopher J.; Peacock, Aaron D.; Giloteaux, L.; Handley, Kim M.; Lovley, Derek R.; Banfield, Jillian F.

    2015-02-01

    Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al. 2003, Williams et al. 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al. 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, that the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ~3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.

  3. Urban structure damaged by differential land level lowering in the lacustrine plain of Queretaro City, Mexico

    Science.gov (United States)

    Ochoa-González, Gil H.; Carreón-Freyre, Dora; Teatini, Pietro; Cerca, Mariano

    2014-05-01

    The Queretaro City, Central Mexico, is placed above a variety of volcanic and sedimentary materials filling a N-S trending graben, with a geomorphologic designation of volcanic valley. The stratigraphic sequence of the filling is mainly composed by lava flows interbedded with an almost 100 m thick pyroclastic unit that was easily eroded by fluvial processes during the Tertiary time. The near surface sequence in the plain is hence composed by alluvial deposits covered by organic silty and clay lacustrine materials. Moreover, as many cities in Mexico, the main source of water supply in Queretaro is groundwater. Groundwater withdrawal caused a 1-3 m/year lowering of the piezometric level and a significant consolidation of the granular materials. Currently, the depth to groundwater table in the lacustrine plain is approximately 120 m deep. The thickness of the granular material varies significantly depending on its location with respect to the normal faults delimiting the main structure of the regional graben. The consolidation on these variably-thick deposits caused differential displacements (e.g., land subsidence) of the ground surface, generating local stress accumulation and fractures. Fracture propagation to the ground surface affected most of the urban structure in the city. We present the correlation of the outcome of a geomechanical model (Ochoa-Gonzalez et al., 2013) with the measured groundwater withdrawal and faulting maps in order to investigate the contribution of the different factors determining the generation of ground fracturing, and to evaluate the associated risk of damage to urban structure in the lacustrine part of the metropolitan area. References G. H. Ochoa-Gonzalez, P. Teatini, D. C. Carreon-Freyre and G. Gambolati, Modeling the deformation of faulted volcano-sedimentary sequences associated to groundwater withdrawal in the Queretaro Valley, Mexico. In: MODSIM 2013 - Adapting to change: the multiple roles of modelling, J. Piantadosi et al. eds

  4. Quantification and regionalization of groundwater-surface water interaction along an alluvial stream

    DEFF Research Database (Denmark)

    Langhoff, Jesper Heidemann; Rasmussen, Keld Rømer; Christensen, Steen

    2006-01-01

    plain divided by the effective width of the stream, can be used as an indicator of the percentage of water entering the stream directly through the streambed. When C is small streambed seepage is large, while when C is large streambed seepage is small and ground water enters the stream mainly as nearly...... the streambed; (ii) as nearly-superficial flow from diffuse discharge areas on the flood plains or; (iii) as a combination of (i) and (ii). At about 40 % of the sites more than 50 % of seepage flows through the streambed. Moreover, it was found that the ratio C, defined as the width of the wet zone of the flood......-superficial or over-bank flow from the wet zone....

  5. The role of floodplain width and alluvial bar growth as a precursor for the formation of anabranching rivers

    Science.gov (United States)

    Morón, S.; Edmonds, D. A.; Amos, K.

    2017-02-01

    Anabranching rivers are defined as a system of multiple channels separated by stable alluvial islands. While substantial progress has been made in developing a physics-based understanding of what drives the differences between meandering and braided river channels, anabranching rivers have not been well-integrated into these models. Here, we propose that alluvial bar growth on the floodplain may be a precursor for the formation of anabranching rivers. Alluvial bar growth strongly depends on the aspect ratio of the flow (width divided by depth) and rivers with wide floodplains have flows with a large aspect ratio. Consistent with this idea, remotely sensed measurements of floodplain width of four rivers from different climatic and tectonic settings show that anabranching river patterns are often associated with relatively wide floodplains. To explore the physics behind that empirical relationship we carried out two sets of morphodynamic numerical simulations using boundary conditions from field-scale modern anabranching rivers spanning different climatic and geologic settings as well as hypothetical floodplain widths. Results from the simulations show that, for a given flood discharge, widening the floodplain changes the river pattern from single channel to multi-threaded with mobile bars to multi-channeled with immobile islands. Multi-channeled patterns arise because the emergence of bars causes flow bifurcation. Subsequent bifurcation instability leads to the emergence of multiple stable channels. As the channels increase their cross-sectional area, shields stresses on intervening bars are reduced until the bars stabilize into islands. We suggest that the presence of stable islands allows vegetation to grow or cohesive sediment to accumulate leading to enhanced channel bank strength and a stable anabranching pattern. Our results suggest that alluvial bar growth can be a precursor to formation of anabranching rivers. Compared with field measurements our simulations

  6. Bacterial community structure in two permafrost wetlands on the Tibetan Plateau and Sanjiang Plain, China.

    Science.gov (United States)

    Yun, Juanli; Ju, Yiwen; Deng, Yongcui; Zhang, Hongxun

    2014-08-01

    Permafrost wetlands are important methane emission sources and fragile ecosystems sensitive to climate change. Presently, there remains a lack of knowledge regarding bacterial communities, especially methanotrophs in vast areas of permafrost on the Tibetan Plateau in Northwest China and the Sanjiang Plain (SJ) in Northeast China. In this study, 16S rRNA-based quantitative PCR (qPCR) and 454 pyrosequencing were used to identify bacterial communities in soils sampled from a littoral wetland of Lake Namco on the Tibetan Plateau (NMC) and an alluvial wetland on the SJ. Additionally, methanotroph-specific primers targeting particulate methane monooxygenase subunit A gene (pmoA) were used for qPCR and pyrosequencing analysis of methanotrophic community structure in NMC soils. qPCR analysis revealed the presence of 10(10) 16S rRNA gene copies per gram of wet soil in both wetlands, with 10(8) pmoA copies per gram of wet soil in NMC. The two permafrost wetlands showed similar bacterial community compositions, which differed from those reported in other cold environments. Proteobacteria, Actinobacteria , and Chloroflexi were the most abundant phyla in both wetlands, whereas Acidobacteria was prevalent in the acidic wetland SJ only. These four phyla constituted more than 80 % of total bacterial community diversity in permafrost wetland soils, and Methylobacter of type I methanotrophs was overwhelmingly dominant in NMC soils. This study is the first major bacterial sequencing effort of permafrost in the NMC and SJ wetlands, which provides fundamental data for further studies of microbial function in extreme ecosystems under climate change scenarios.

  7. Behaviour of boron and strontium isotopes in groundwater-aquifer interactions in the Cornia Plain (Tuscany, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Pennisi, Maddalena [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy)]. E-mail: M.Pennisi@igg.cnr.it; Bianchini, Gianluca [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy); Dipartimento di Scienze della Terra, Universita di Ferrara (Italy); Muti, Antonio [Azienda Servizi Ambientali, Area Val di Cornia, Livorno (Italy); Kloppmann, Wolfram [Bureau des Recherches Geologiques et Minieres, Orleans (France); Gonfiantini, Roberto [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy)

    2006-07-15

    The Cornia Plain alluvial aquifer, in Tuscany, is exploited intensely to meet the demand for domestic, irrigation and industrial water supplies. The B concentration of groundwater, however, is often above the European limit of 1 mg L{sup -1}, with the result that exploitation of these water resources requires careful management. Boron and Sr isotopes have been used as part of a study on the origin and distribution of B dissolved in groundwater, and indirectly as a contribution to the development of appropriate water management strategies. The geochemistry of the Cornia Plain groundwater changes from a HCO{sub 3} facies in the inland areas to a Cl facies along the coastal belt, where seawater intrusion takes place. The B concentration of groundwater increases towards the coastal areas, while the {sup 11}B/{sup 10}B ratio decreases. This indicates that there is an increasing interaction between dissolved B and the sediments forming the aquifer matrix, whose B content is in the order of 100 mg kg{sup -1}. Adsorption-desorption exchanges take place between water and the sediment fine fraction rich in clay minerals, with a net release of B from the matrix into the groundwater, and a consequent {delta} {sup 11}B shift from positive to negative values. The aquifer matrix sediments therefore seem to be the major source of B dissolved in the groundwater. The groundwater-matrix interactions triggered by the ionic strength increase caused by seawater intrusion can also be detected in the Ca-Na ion exchanges. Dissolved Sr follows a trend similar to that of Ca, while the {sup 87}Sr/{sup 86}Sr ratio is equal to that of the exchangeable Sr of the aquifer matrix and therefore does not change significantly. These results have helped to define a new strategy for groundwater exploitation, with the final objective of reducing B concentration in the water extracted from the aquifer.

  8. Viking 2 Image of Mars Utopian Plain

    Science.gov (United States)

    1976-01-01

    The boulder-strewn field of red rocks reaches to the horizon nearly two miles from Viking 2 on Mars' Utopian Plain. Scientists believe the colors of the Martian surface and sky in this photo represent their true colors. Fine particles of red dust have settled on spacecraft surfaces. The salmon color of the sky is caused by dust particles suspended in the atmosphere. Color calibration charts for the cameras are mounted at three locations on the spacecraft. Note the blue starfield and red stripes of the flag. The circular structure at top is the high-gain antenna, pointed toward Earth. Viking 2 landed September 3, 1976, some 4600 miles from its twin, Viking 1, which touched down on July 20.

  9. Assessment of intrinsic vulnerability of an alluvial aquifer under anthropogenic pressure: cross comparison of 4 index-based groundwater vulnerability mapping models within the Biguglia lagoon watershed (Corsica, France).

    Science.gov (United States)

    Jaunat, Jessy; Huneau, Frédéric; Garel, Emilie; Devos, Alain; Lejeune, Olivier

    2016-04-01

    KEYWORDS: Alluvial aquifer, Vulnerability mapping, Index-based methods, DRASTIC, SINTACS, SI, GOD The geographical position of the Biguglia lagoon watershed south of the Bastia city (80 000 inhabitants), lead to a highly vulnerable hydrosystem setting. This littoral plain is the unique territory available for the urbanisation and for the agriculture activities (cattle breeding). All the activities developed are likely to have a qualitative impact on water infiltration and therefore on groundwater, which is in hydraulic connection with the lagoon system. Beyond this ecological issue, groundwater of this watershed is intensively used as drinking water supply. It appears essential to control the long-term groundwater quality of the Biguglia plain which is the major economic zone of Corsica. Achievement of this issue requires the identification of the areas where the alluvial aquifer is mostly vulnerable to anthropogenic activities. The results given by 4 of the most popular index-based vulnerability mapping methods (DRASTIC, SI, SINTACS and GOD) are compared. The water table, net recharge, aquifer and soils properties, topography, vadose zone and land uses have been precisely mapped and numerically translated in GIS with a 25m precision. 4 final maps were finally compiled according to the weighting factors of each methods. Hydrochemical investigations were also carried out on 30 sampling points (major ions and anthropogenic tracers) to evaluate the effect of anthropogenic activities on groundwater quality and also to validate the results of the vulnerability mapping. A comparison between the parametric models shows a significant agreement between the DRASTIC, SINTACS and SI results (2% to 5% of the total area in very low vulnerability class, 10% to 13% in low vulnerability, 16% to 23% in medium vulnerability, 31% to 53% in high vulnerability and 14% to 23% in very high vulnerability). The two first methods are quite similar, which explains the proximity of the

  10. Monuments culturels historiques dans la Plaine Roumaine

    Directory of Open Access Journals (Sweden)

    FLORINA GRECU

    2013-10-01

    Full Text Available Ce travail met en évidence le rôle de la position gé ographique dans le développement des objectifs culturels d’importance touristique et sci entifique locale, régionale ou nationale (les géosites culturels. Dans le développement des géos ites culturels de la Plaine Roumaine plusieurs étapes s’individualisent, avec des caractéristiques spécifiques: a l’étape prédaco-romaine avec les géosites néolithiques ; b l’étape daco-romaine , période dans laquelle des villes sont apparues le long des rivières allochtones (Argedava et du D anube (Turnu Magurele et Zimnicea ; c l’étape médiévale , à laquelle sont particulières les villes avec une spécificité architecturelle (Calafat, Braila et Galati et la capitale, Bucarest, fondée en 1459 ; d l’étape moderne des monuments d’une architecture nouvelle ; e l’étape contemporaine / socialiste (1948-1989 ; f l’étape actuelle (après 1989, caractérisée par un mélange d’architectures avec un impact sur l’évolution du phénomène touristique. La Plaine Roum aine, du à ses caractéristiques physico- géographiques et historiques, réunit une palette la rge de géosites culturels qui pourraient se transformer en vrais objectifs touristiques.

  11. Radon and thoron levels, their spatial and seasonal variations in adobe dwellings - a case study at the great Hungarian plain.

    Science.gov (United States)

    Szabó, Zsuzsanna; Jordan, Gyozo; Szabó, Csaba; Horváth, Ákos; Holm, Óskar; Kocsy, Gábor; Csige, István; Szabó, Péter; Homoki, Zsolt

    2014-06-01

    Radon and thoron isotopes are responsible for approximately half of the average annual effective dose to humans. Although the half-life of thoron is short, it can potentially enter indoor air from adobe walls. Adobe was a traditional construction material in the Great Hungarian Plain. Its major raw materials are the alluvial sediments of the area. Here, seasonal radon and thoron activity concentrations were measured in 53 adobe dwellings in 7 settlements by pairs of etched track detectors. The results show that the annual average radon and thoron activity concentrations are elevated in these dwellings and that the proportions with values higher than 300 Bq m(-3) are 14-17 and 29-32% for radon and thoron, respectively. The calculated radon inhalation dose is significantly higher than the world average value, exceeding 10 mSv y(-1) in 7% of the dwellings of this study. Thoron also can be a significant contributor to the inhalation dose with about 30% in the total inhalation dose. The changes of weather conditions seem to be more relevant in the variation of measurement results than the differences in the local sedimentary geology. Still, the highest values were detected on clay. Through the year, radon follows the average temperature changes and is affected by the ventilation, whereas thoron rather seems to follow the amount of precipitation.

  12. Accumulation of natural SF6 in the sedimentary aquifers of the North China Plain as a restriction on groundwater dating.

    Science.gov (United States)

    von Rohden, Christoph; Kreuzer, Andreas; Chen, Zongyu; Aeschbach-Hertig, Werner

    2010-09-01

    We employed environmental tracers ((3)H-(3)He, SF(6)) in a study investigating the groundwater recharge in the North China Plain (NCP), a sedimentary aquifer system consisting of fluvial and alluvial river deposits near the city of Shijiazhuang. The (3)H-(3)He dating method revealed reasonable results for the young groundwater with ages covering the range of recent to ~40 a. SF(6) samples were taken in parallel for independent dating and to compare the applicability of both methods. However, the SF(6)-results are influenced and, in part, dominated by a systematic non-atmospheric component, revealing that the dating with SF(6) is unreliable in this region. A correlation of non-atmospheric SF(6) and (3)H-(3)He ages suggests a continuous accumulation of natural SF(6) in the groundwater of the NCP aquifers. Although terrigenic SF(6) has previously been associated with crystalline or igneous rocks, our results indicate that it can also be accumulated in sandy aquifers on the timescale relevant for SF(6) dating.

  13. Sedimentation patterns across a Coastal Plain floodplain: The importance of hydrogeomorphic influences and cross-floodplain connectivity

    Science.gov (United States)

    Kaase, Christopher T.; Kupfer, John A.

    2016-09-01

    The floodplains of large Coastal Plain rivers in the southeastern U.S. are important long-term storage sites for alluvial sediment and nutrients. Yet considerable uncertainty surrounds sediment dynamics on many large river floodplains and, in particular, the local scale factors that affect the flux of sediment and nutrients from rivers onto their floodplains and their subsequent deposition. This research quantifies short-term rates of sediment deposition from 2012 to 2014 on floodplain sites at Congaree National Park using feldspar pads. Sediment deposition rates ranged from 0.1 to 15.6 cm (median = 1.46 cm) and were closely associated with inundation frequency and geomorphic position. Cross-floodplain distributary channels served as particularly important conduits for moving sediment onto the floodplain. Physical and chemical analyses of soil samples demonstrated that the most flood-exposed sites had higher major nutrient and micronutrient levels (especially of phosphorus) and more diverse nutrient compositions. This research advances current understandings of lateral floodplain connectivity by demonstrating the complex effects of regional hydrology and local floodplain environmental characteristics on the supply of sediment and nutrients.

  14. Perceptions of branded and plain cigarette packaging among Mexican youth.

    Science.gov (United States)

    Mutti, Seema; Hammond, David; Reid, Jessica L; White, Christine M; Thrasher, James F

    2016-01-29

    Plain cigarette packaging, which seeks to remove all brand imagery and standardize the shape and size of cigarette packs, represents a novel policy measure to reduce the appeal of cigarettes. Plain packaging has been studied primarily in high-income countries like Australia and the UK. It is unknown whether the effects of plain packaging may differ in low-and-middle income countries with a shorter history of tobacco regulation, such as Mexico. An experimental study was conducted in Mexico City to examine perceptions of branded and plain cigarette packaging among smoking and non-smoking Mexican adolescents (n = 359). Respondents were randomly assigned to a branded or plain pack condition and rated 12 cigarette packages for appeal, taste, harm to health and smoker-image traits. As a behavioral measure of appeal, respondents were offered (although not given) four cigarette packs (either branded or plain) and asked to select one to keep. The findings indicated that branded packs were perceived to be more appealing (β = 3.40, p < 0.001) and to contain better tasting cigarettes (β = 3.53, p < 0.001), but were not perceived as less harmful than plain packs. Participants rated people who smoke the branded packs as having relatively more positive smoker-image traits overall (β = 2.10, p < 0.001), with particularly strong differences found among non-smokers for the traits 'glamorous', 'stylish', 'popular' and 'sophisticated' (p < 0.001). No statistically significant difference was found for the proportion of youth that accepted when offered branded compared with plain packs. These results suggest that plain packaging may reduce brand appeal among Mexican youth, consistent with findings in high-income countries.

  15. Temperature Variation of Jiamusi Region in Sanjiang Plain

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The study aimed at analysing the change characteristics of temperature in Jiamusi region of Sanjiang Plain.[Method] Based on temperature data of Jiamusi region in Sanjiang Plain from 1961 to 2010,including Jiamusi,Huanan,Fujin and Fuyuan station,we studied the change trends,abrupt climate change and abnormal years of temperature in Jiamusi region.[Result] Annual average temperature of Jiamusi region in Sanjiang Plain showed increasing trend,with the increase of 0.249-0.412 ℃/10 a.The order of an...

  16. Sustainable Authorship in Plain Text using Pandoc and Markdown

    Directory of Open Access Journals (Sweden)

    Dennis Tenen

    2014-03-01

    Full Text Available In this tutorial, you will first learn the basics of Markdown—an easy to read and write markup syntax for plain text—as well as Pandoc, a command line tool that converts plain text into a number of beautifully formatted file types: PDF, .docx, HTML, LaTeX, slide decks, and more.1 With Pandoc as your digital typesetting tool, you can use Markdown syntax to add figures, a bibliography, formatting, and easily change citation styles from Chicago to MLA (for instance, all using plain text.

  17. 长江中游典型分汊河段河床演变%Alluvial process analysis of typical braided reach in middle reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    刘万利; 伍文俊; 余新明

    2011-01-01

    戴家洲河段来水来沙特点分析表明,本河段具有明显的平原河流特征,水流易受地形影响,河段年际间来水来沙存在较大的变化,来沙以流域产沙为主,河段内造床起主导作用的是悬移质泥沙运动.河段演变特点主要表现为:洪水河势基本稳定而中低水滩地则冲淤变化不定,池湖港心滩基本稳定,巴河边滩发育和冲蚀交替,戴家洲洲头不断变化,直港直水道和微弯水道特征不断转化交替,巴河边滩的消长、戴家洲洲头的进退和直港滩槽演变密切相关,戴家洲直港浅滩位置多变且呈洪淤枯冲规律.结合三峡水利枢纽的蓄水运用,对戴家洲河段河床演变趋势进行了预估.%The characters of runoff and sediment of Daijiazhou reach in middle reaches of the Yangtze river is analyzed.It is shown that the plain river characteristics of Daijiazhou reach is obvious.The runoff and sediment between the years vary largely.The suspended load plays an important role in alluvial process.The characters of river evolution are as follows: the flood river regime is stable whereas the low-water riverbed is unstable;the Chihugang shoal is basically stable;the deposition and erosion of Bahe point bar is alternating;the head of Daijiazhou sandbar is constantly changing;Zhigang channel alternate between slightly curved channel characteristics and straight channel characteristics;Bahe point bar and the head of Daijiazhou sandbar are closely related to Zhigang channel condition;the position of Zhigang shoal is frequent changing.Combined with impoundment of the Three Gorges Dam,the fluvial tendency of Daijiazhou reach is predicted.

  18. How does sediment affect the hydraulics of bedrock-alluvial rivers?

    Science.gov (United States)

    Hodge, Rebecca; Hoey, Trevor; Maniatis, George; Leprêtre, Emilie

    2016-04-01

    Relationships between flow, sediment transport and channel morphology are relatively well established in coarse-grained alluvial channels. Developing equivalent relationships for bedrock-alluvial channels is complicated by the two different components that comprise the channel morphology: bedrock and sediment. These two components usually have very different response times to hydraulic forcing, meaning that the bedrock morphology may be inherited from previous conditions. The influence of changing sediment cover on channel morphology and roughness will depend on the relative magnitudes of the sediment size and the spatial variations in bedrock elevation. We report results from experiments in a 0.9m wide flume designed to quantify the interactions between flow and sediment patch morphology using two contrasting bedrock topographies. The first topography is a plane bed with sand-scale roughness, and the second is a 1:10 scale, 3D printed, model of a bedrock channel with spatially variable roughness (standard deviation of elevations = 12 mm in the flume). In all experiments, a sediment pulse was added to the flume (D50 between 7 and 15 mm) and sediment patches were allowed to stabilise under constant flow conditions. The flow was then incrementally increased in order to identify the discharges at which sediment patches and isolated grains were eroded. In the plane bed experiments ˜20% sediment cover is sufficient to alter the channel hydraulics through the increased roughness of the bed; this impact is expressed as the increased discharge at which isolated grains are entrained. In the scaled bed experiments, partial sediment cover decreased local flow velocities on a relatively smooth area of the bed. At the scale of the entire channel, the bed morphology, and the hydraulics induced by it, was a primary control on sediment cover stability at lower sediment inputs. At higher inputs, where sediment infilled the local bed topography, patches were relatively more stable

  19. Investigating the impact of vegetation on alluvial fans using laboratory experiments

    Science.gov (United States)

    Clarke, Lucy; McLelland, Stuart; Tom, Coutlhard

    2016-04-01

    Riparian vegetation can significantly influence the geomorphology of fluvial systems, affecting channel geometry and flow dynamics. However, there is still limited understanding of the role vegetation plays in the development of alluvial fans, despite the large number of vegetated fans located in temperate and humid climates. An understanding of the feedback loops between water flow, sediment dynamics and vegetation is key to understanding the geomorphological response of alluvial fans. But it is difficult to investigate these relationships in the natural world due to the complexity of the geomorphic and biological processes and timescales involved, whereas the controlled conditions afforded by laboratory experiments provide the ideal opportunity to explore these relationships. To examine the effects of vegetation on channel form, flow dynamics and morphology during fan evolution, a series of experiments were conducted using the Total Environment Simulator (operated by the University of Hull). The experiments followed a 'similarity of processes' approach and so were not scaled to a specific field prototype. Live vegetation (Medicago Sativa) was used to simulate the influence of vegetation on the fan development. A range of experiments were conducted on 2x2m fan plots, the same initial conditions and constant water discharge and sediment feed rates were used, but the vegetation density and amount of geomorphic time (when the sediment and water were running and there was active fan development) between seeding / vegetation growth varied between runs. The fan morphology was recorded at regular intervals using a laser scanner (at 1mm resolution) and high resolution video recording and overhead photography were used to gain near-continuous data quantifying fan topography, flow patterns, channel migration and avulsion frequency. Image analysis also monitored the spatial extent of vegetation establishment. The use of these techniques allowed collection of high resolution

  20. Alluvial fan sensitivity to glacial-interglacial climate change: case studies from Death Valley.

    Science.gov (United States)

    Whittaker, Alexander; D'Arcy, Mitch; Roda-Boluda, Duna; Brooke, Sam

    2016-04-01

    The effects of climate change on eroding landscapes and the sedimentary record remain poorly understood. The measurement of regional grain size trends in stream-flow deposits provides one way to address this issue because, in principle, these trends embed important information on the dynamics of sediment routing systems and their sensitivity to external forcings. In many cases, downstream stratigraphic fining is primarily driven by selective deposition of sediment. The relative efficiency of this process is determined by the physical characteristics of the input sediment supply and the spatial distribution of subsidence rate, which generates the accommodation necessary for mass extraction. Here, we measure grain size fining rates from apex to toe for alluvial fan systems in Death Valley, California, which have well-exposed modern and late Pleistocene deposits, where the long-term tectonic boundary conditions are known and where climatic variation over this time period is well-constrained. Our field data demonstrate that input grain sizes and input fining rates do vary noticeably over the late Pleistocene-Holocene period in this study area, although there is little evidence for significant changes in rates of faulting in the last 200 ky. For two catchments in the Grapevine Mountains for which we have excellent stratigraphic constraints on modern and 70 ka fan deposits, we use a self-similarity based grain size fining model to understand changes in sediment flux to the fans over this time period. When calibrated with cosmogenically-derived catchment erosion rates, our results show that a 30 % decrease in average precipitation rate over this time-frame led to a 20 % decrease in sediment flux to the fans, and a clear increase in the down-fan rate of fining. This supports existing landscape evolution models that relate a decrease in precipitation rate to a decrease in sediment flux, but implies that the relationship between sediment flux and precipitation rate may be

  1. Metatranscriptomic Analysis Reveals Unexpectedly Diverse Microbial Metabolism in a Biogeochemical Hot Spot in an Alluvial Aquifer

    Science.gov (United States)

    Jewell, Talia N. M.; Karaoz, Ulas; Bill, Markus; Chakraborty, Romy; Brodie, Eoin L.; Williams, Kenneth H.; Beller, Harry R.

    2017-01-01

    Organic matter deposits in alluvial aquifers have been shown to result in the formation of naturally reduced zones (NRZs), which can modulate aquifer redox status and influence the speciation and mobility of metals, affecting groundwater geochemistry. In this study, we sought to better understand how natural organic matter fuels microbial communities within anoxic biogeochemical hot spots (NRZs) in a shallow alluvial aquifer at the Rifle (CO) site. We conducted a 20-day microcosm experiment in which NRZ sediments, which were enriched in buried woody plant material, served as the sole source of electron donors and microorganisms. The microcosms were constructed and incubated under anaerobic conditions in serum bottles with an initial N2 headspace and were sampled every 5 days for metagenome and metatranscriptome profiles in combination with biogeochemical measurements. Biogeochemical data indicated that the decomposition of native organic matter occurred in different phases, beginning with mineralization of dissolved organic matter (DOM) to CO2 during the first week of incubation, followed by a pulse of acetogenesis that dominated carbon flux after 2 weeks. A pulse of methanogenesis co-occurred with acetogenesis, but only accounted for a small fraction of carbon flux. The depletion of DOM over time was strongly correlated with increases in expression of many genes associated with heterotrophy (e.g., amino acid, fatty acid, and carbohydrate metabolism) belonging to a Hydrogenophaga strain that accounted for a relatively large percentage (~8%) of the metatranscriptome. This Hydrogenophaga strain also expressed genes indicative of chemolithoautotrophy, including CO2 fixation, H2 oxidation, S-compound oxidation, and denitrification. The pulse of acetogenesis appears to have been collectively catalyzed by a number of different organisms and metabolisms, most prominently pyruvate:ferredoxin oxidoreductase. Unexpected genes were identified among the most highly expressed

  2. Great Plains Wind Energy Transmission Development Project

    Energy Technology Data Exchange (ETDEWEB)

    Brad G. Stevens, P.E.; Troy K. Simonsen; Kerryanne M. Leroux

    2012-06-09

    In fiscal year 2005, the Energy & Environmental Research Center (EERC) received funding from the U.S. Department of Energy (DOE) to undertake a broad array of tasks to either directly or indirectly address the barriers that faced much of the Great Plains states and their efforts to produce and transmit wind energy at the time. This program, entitled Great Plains Wind Energy Transmission Development Project, was focused on the central goal of stimulating wind energy development through expansion of new transmission capacity or development of new wind energy capacity through alternative market development. The original task structure was as follows: Task 1 - Regional Renewable Credit Tracking System (later rescoped to Small Wind Turbine Training Center); Task 2 - Multistate Transmission Collaborative; Task 3 - Wind Energy Forecasting System; and Task 4 - Analysis of the Long-Term Role of Hydrogen in the Region. As carried out, Task 1 involved the creation of the Small Wind Turbine Training Center (SWTTC). The SWTTC, located Grand Forks, North Dakota, consists of a single wind turbine, the Endurance S-250, on a 105-foot tilt-up guyed tower. The S-250 is connected to the electrical grid on the 'load side' of the electric meter, and the power produced by the wind turbine is consumed locally on the property. Establishment of the SWTTC will allow EERC personnel to provide educational opportunities to a wide range of participants, including grade school through college-level students and the general public. In addition, the facility will allow the EERC to provide technical training workshops related to the installation, operation, and maintenance of small wind turbines. In addition, under Task 1, the EERC hosted two small wind turbine workshops on May 18, 2010, and March 8, 2011, at the EERC in Grand Forks, North Dakota. Task 2 involved the EERC cosponsoring and aiding in the planning of three transmission workshops in the midwest and western regions. Under Task

  3. Imaging normal faults in alluvial fans using geophysical techniques: Field example from the coast of Gulf of Aqaba, Saudi Arabia

    KAUST Repository

    Hanafy, Sherif M.

    2014-08-05

    In this work we use geophysical methods to locate and characterize active faults in alluvial sediments. Since only subtle material and velocity contrasts are expected across the faults, we used seismic refraction tomography and 2D resistivity imaging to locate the fault. One seismic profile and one 2D resistivity profile are collected at an alluvial fan on the Gulf of Aqaba coast in Saudi Arabia. The collected data are inverted to generate the traveltime tomogram and the electric resistivity tomogram (ERT). A low velocity anomaly is shown on the traveltime tomogram indicates the colluvial wedge associated with the fault. The location of the fault is shown on the ERT as a vertical high resistivity anomaly.

  4. Numerical modelling of shaking effects due to strong motions on the tiber alluvial deposits in Rome (Italy)

    CERN Document Server

    Bonilla, Fabian; Gelis, Céline; Giacomi, Anna Chiara; Lenti, Luca; Martino, Salvatore; d'Avila, Maria Paola Santisi; Semblat, Jean-François

    2016-01-01

    A multidisciplinary approach is proposed for evaluating the effects of shaking due to strong motions on the Tiber river alluvial deposits in Rome's historical centre. At this aim, a detailed 3D geological model of the Tiber river alluvial deposit has been constructed and a numerical analysis of site response was performed along two geological sections across the historical centre of Rome. The numerical models were performed in both 1D and 2D configurations assuming linear and nonlinear conditions, by applying a three component seismic input. The results show that the maximum shear strains are strongly conditioned by the layer geometries (i.e. 2D or 1D conditions) and by the soil heterogeneity. Moreover, the reliability of the maximum strains obtained by numerical modeling is discussed comparing these values respect to both the volumetric and the degradation dynamic thresholds of the considered soils.

  5. Selected Basin Characterization Model Parameters for the Great Basin Carbonate and Alluvial Aquifer System of Nevada, Utah, and Parts of Adjacent States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a study focusing on ground-water resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a...

  6. 1:1,000,000-scale hydrographic areas and flow systems for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer...

  7. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of a constant recharge value for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake...

  8. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of a constant hydraulic conductivity value for the alluvial and terrace deposits along the North Canadian River from...

  9. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in northwestern Oklahoma....

  10. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of constant hydraulic conductivity values for the alluvial and terrace deposits along the Cimarron River from Freedom to...

  11. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital water-level elevation contours for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake...

  12. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital water-level elevation contours for the alluvial and terrace deposits along the Cimarron River in northwestern Oklahoma during...

  13. Three-dimensional hydrogeologic framework for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a...

  14. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in northwestern Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of a constant recharge rate for the alluvial and terrace deposits along the Cimarron River from Freedom to Guthrie in...

  15. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in...

  16. 1:1,000,000-scale potentiometric contours and control points for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer...

  17. The Great Plains IDEA Gerontology Program: An Online, Interinstitutional Graduate Degree

    Science.gov (United States)

    Sanders, Gregory F.

    2011-01-01

    The Great-Plains IDEA Gerontology Program is a graduate program developed and implemented by the Great Plains Interactive Distance Education Alliance (Great Plains IDEA). The Great Plains IDEA (Alliance) originated as a consortium of Colleges of Human Sciences ranging across the central United States. This Alliance's accomplishments have included…

  18. Analysis of High Plains Resource Risk and Economic Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Tidwell, Vincent C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vargas, Vanessa N [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Shannon M [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dealy, Bern Caudill [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shaneyfelt, Calvin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, Braeton James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moreland, Barbara Denise [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-04-01

    The importance of the High Plains Aquifer is broadly recognized as is its vulnerability to continued overuse. T his study e xplore s how continued depletions of the High Plains Aquifer might impact both critical infrastructure and the economy at the local, r egional , and national scale. This analysis is conducted at the county level over a broad geographic region within the states of Kansas and Nebraska. In total , 140 counties that overlie the High Plains Aquifer in these two states are analyzed. The analysis utilizes future climate projections to estimate crop production. Current water use and management practices are projected into the future to explore their related impact on the High Plains Aquifer , barring any changes in water management practices, regulat ion, or policy. Finally, the impact of declining water levels and even exhaustion of groundwater resources are projected for specific sectors of the economy as well as particular elements of the region's critical infrastructure.

  19. 49 CFR 215.111 - Defective plain bearing.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD FREIGHT CAR SAFETY STANDARDS Freight Car Components Suspension System § 215.111 Defective plain bearing. A railroad may not place or continue in service a car, if the car...

  20. Whooping crane stopover site use intensity within the Great Plains

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Whooping cranes (Grus americana) of the Aransas- Wood Buffalo population migrate twice each year through the Great Plains in North America. Recovery activities for...

  1. Aerial Images of Alaska's Arctic Coastal Plain; 1974-1979

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is comprised of 10 aerial images of three different study areas on Alaska's Arctic Coastal Plain flown by NASA in 1974, 1977, 1979 and obtained from the...

  2. Vegetation - Carrizo Plain ER, 2005 - 2008 [ds561

    Data.gov (United States)

    California Department of Resources — The Vegetation Map of the Carrizo Plain Ecological Reserve, San Luis Obispo County, California was created by the California Department of Fish and Game (DFG)...

  3. Physiography for the Mid-Atlantic Coastal Plain

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Physiography for the Mid-Atlantic Coastal Plain was constructed by standardizing and extrapolating previous physiographic interpretations for areas within and...

  4. Subcropping Geology for the Mid-Atlantic Coastal Plain

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Subcropping geology for the Mid-Atlantic Coastal Plain was compiled and interpreted from available published sources. Formation contacts were interpolated across...

  5. Particulate Loads Caused by Wind Erosion in the Great Plains

    Science.gov (United States)

    Hagen, Lawrence J.; Woodruff, Neil P.

    1975-01-01

    In this paper the annual flux of suspended particulates caused by wind erosion in the Great Plains is estimated. This study demonstrated that climate causes wide variations in air pollution from wind erosion. (BT)

  6. Snake River Plain Basin-fill aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Snake River Plain aquifer system, which includes both the basaltic and basin-fill aquifers. This dataset does not...

  7. Southern Great Plains rapid ecoregional assessment : Pre-assessment report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the Pre-Assessment Report for the Southern Great Plains Rapid Ecoregional Assessment (REA) is to document the selection process for and final list of...

  8. 2003 Pearl River County, Mississippi Lidar: Flood Plain Management Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This lidar data was collected primarily for flood plain mapping within Pearl River County, MS. The data were processed into separate Bare Earth and First Surface...

  9. Alluvial fan facies of the Yongchong Basin: Implications for tectonic and paleoclimatic changes during Late Cretaceous in SE China

    Science.gov (United States)

    Chen, Liuqin; Steel, Ronald J.; Guo, Fusheng; Olariu, Cornel; Gong, Chenglin

    2017-02-01

    Late Cretaceous continental redbeds, the Guifeng Group of the Yongchong Basin in SE China have been investigated to conduct detailed fan facies description and interpretation. Tectonic activities determined the alluvial fan development along the basin margin, but the alluvial facies was linked with paleoclimate changes. The Guifeng Group is divided into the Hekou, Tangbian and Lianhe formations in ascending order. The Hekou conglomerates are typically polymict, moderately sorted with erosional bases, cut-and-fill features, normal grading and sieve deposits, representing dominant stream-flows on alluvial fans during the initial opening stage of the basin infill. The Tangbian Formation, however, is characterized by structureless fine-grained sediments with dispersed coarse clasts, and couplets of conglomerate and sandstone or siltstone and mudstone, recording a change to a playa and ephemeral lake environments with occasional stream flooding, thus indicating a basin expanding stage. The hallmark of the Lianhe Formation is disorganized, poorly sorted conglomerates lack of erosional bases, and a wide particle-size range from clay to boulders together reflect mud-rich debris-flows accumulating on fans, likely related to reactivation of faulting along the northwestern mountain fronts during a post-rift stage. The depositional system changes from stream-flows up through playa with ephemeral streams to debris-flows during the accumulation of the three formations are thus attributed to different source rocks and climatic conditions. Therefore, the fluvial-dominated fans of the Hekou Formation recorded a subhumid paleoclimate (Coniacian-Santonian Age). The dominant semiarid climate during the Campanian Age produced abundant fine-grained sediments in the playa and ephemeral lake environments of the Tangbian Formation. A climatic change towards more humidity during the late stage of the Guifeng Group (Maastrichtian Age) probably yielded high deposition rate of coarse clasts in

  10. A multiple-point geostatistical method for characterizing uncertainty of subsurface alluvial units and its effects on flow and transport

    Science.gov (United States)

    Cronkite-Ratcliff, C.; Phelps, G.A.; Boucher, A.

    2012-01-01

    This report provides a proof-of-concept to demonstrate the potential application of multiple-point geostatistics for characterizing geologic heterogeneity and its effect on flow and transport simulation. The study presented in this report is the result of collaboration between the U.S. Geological Survey (USGS) and Stanford University. This collaboration focused on improving the characterization of alluvial deposits by incorporating prior knowledge of geologic structure and estimating the uncertainty of the modeled geologic units. In this study, geologic heterogeneity of alluvial units is characterized as a set of stochastic realizations, and uncertainty is indicated by variability in the results of flow and transport simulations for this set of realizations. This approach is tested on a hypothetical geologic scenario developed using data from the alluvial deposits in Yucca Flat, Nevada. Yucca Flat was chosen as a data source for this test case because it includes both complex geologic and hydrologic characteristics and also contains a substantial amount of both surface and subsurface geologic data. Multiple-point geostatistics is used to model geologic heterogeneity in the subsurface. A three-dimensional (3D) model of spatial variability is developed by integrating alluvial units mapped at the surface with vertical drill-hole data. The SNESIM (Single Normal Equation Simulation) algorithm is used to represent geologic heterogeneity stochastically by generating 20 realizations, each of which represents an equally probable geologic scenario. A 3D numerical model is used to simulate groundwater flow and contaminant transport for each realization, producing a distribution of flow and transport responses to the geologic heterogeneity. From this distribution of flow and transport responses, the frequency of exceeding a given contaminant concentration threshold can be used as an indicator of uncertainty about the location of the contaminant plume boundary.

  11. The potential for groundwater contamination along basin margins in the arid west: Alluvial fans and lake features

    OpenAIRE

    Clyde, Calvin G.; Oaks, Robert Q.; Peter T. Kolesar; Fisk, Edward P.

    1981-01-01

    Many towns of the arid west were built upon alluvial fans and upon sites underlain by Pleistocene lake deposits. The objective of this study was to assess the potential impact of these activities of man upon groundwater quality within these geological features. Emphasis was placed on shallow groundwater quality after it was determined that deep groundwater is rarely contaminated at such sites. A reconnaissance of...

  12. Risk assessment of heavy metal pollution in alluvial soils and sediments of the Grote Beek river (Belgium)

    OpenAIRE

    Cappuyns, Valérie; Swennen, Rudy

    2003-01-01

    Consoil 2003 RISK ASSESSMENT OF HEAVY METAL POLLUTION IN ALLUVIAL SOILS AND SEDIMENTS OF THE GROTE BEEK RIVER (BELGIUM) Valérie Cappuyns, Rudy Swennen and Katrien De Nil Katholieke Universiteit Leuven, Fysico-chemische Geologie, Celestijnenlaan 200C, 3001 Heverlee, Belgium Tel. +3216327297, Fax. +3216327981, e-mail: 1. Introduction Wastewater discharge from the processing of phosphate ores has contributed to pollution by heavy metals ...

  13. 100 years of mapping the Holocene Rhine-Meuse delta plain: combining research and teaching

    Science.gov (United States)

    Cohen, K. M.; Stouthamer, E.; Hoek, W. Z.; Middelkoop, H.

    2012-04-01

    The history of modern soil, geomorphological and shallow geological mapping in the Holocene Rhine-Meuse delta plain goes back about 100 years. The delta plain is of very heterogeneous build up, with clayey and peaty flood basins, dissected by sandy fluvial distributary channel belts with fine textured levees grading into tidal-influenced rivers and estuaries. Several generations of precursor rivers occur as alluvial ridges and buried ribbon sands. They form an intricate network originating from repeated avulsions, back to 8000 years ago. Present rivers have been embanked since ca. 1250 AD and the delta plain (~ 3000 km2) has been reclaimed for agriculture. Soils are young and subject to oxidation and compaction. The first detailed field map of channel belts and floodbasins was made in 1926 by Vink, a geography teacher from Amsterdam. Soil mapping and Holocene geology gained interest after WW-II, with Wageningen soil scientists Edelman, Hoeksema and Pons taking lead. Utrecht University started teaching and research on the subject in 1959, launching an undergraduate mapping field course based on hand augering and field observation. An archive of borehole logs and local maps started to build up. Initially focused on soil mapping, from 1973 the course shifted to a geomorphological-geological focus. Berendsen took over supervision, introduced standard description protocols and legends and increased coring depth. This resulted in 1982 in his influential PhD thesis on the Rhine delta's genesis. New coring and sampling methods came and extensive 14C dating campaigns began. With steadily increasing numbers of students, accumulation of data speeded up, and increasingly larger parts of the delta were mapped. The academic mapping ran in parallel with soil survey and geological survey mapping campaigns. The computer was introduced in the field course and digital data archiving began in 1989. A series of PhD studies on thematic aspects of delta evolution and an increasing number

  14. Some tactile comfort properties of plain knitted fabrics

    OpenAIRE

    Stanković, Snežana; Bizjak, Matejka

    2011-01-01

    The sensory perception of textile materials is related to mechanical stimuli due to pressure and friction forces, so the softness and surface properties are considered to be the key parameters of fabric hand. The aim of this study was to investigate the influence of the fibre type, yarn structure and spinning technique on softness and surface properties of plain knitted fabrics. Plain knitted fabrics (jersey) were produced from the two- assembled hemp, viscose and cotton yarns so as to obtain...

  15. Phosphate-solubility and phosphatase activity in Gangetic alluvial soil as influenced by organophosphate insecticide residues.

    Science.gov (United States)

    Majumder, Shyam Prasad; Das, Amal Chandra

    2016-04-01

    An experiment was conducted under laboratory conditions to investigate the effect of four organophosphate insecticides, viz. monocrotophos, profenophos, quinalphos and triazophos at their field application rates (0.75, 1.0, 0.5 and 0.6 kg a.i.ha(-1), respectively), on the growth and activities of phosphate solubilizing microorganisms in relation to availability of insoluble phosphates in the Gangetic alluvial soil of West Bengal, India. The proliferation of phosphate solubilizing microorganisms was highly induced with profenophos (38.3%), while monocrotophos exerted maximum stimulation (20.8%) towards the solubility of insoluble phosphates in soil. The phosphatase activities of the soil (both acid phosphatase and alkaline phosphatase) were significantly increased due to the incorporation of the insecticides in general, and the augmentation was more pronounced with quinalphos (43.1%) followed by profenophos (27.6%) for acid phosphatase, and with monocrotophos (25.2%) followed by profenophos (16.1%) for alkaline phosphatase activity in soil. The total phosphorus was highly retained by triazophos (19.9%) followed by monocrotophos (16.5%), while incorporation of triazophos and quinalphos manifested greater availability of water soluble phosphorus in soil.

  16. DAM IMPACTS ON AND RESTORATION OF AN ALLUVIAL RIVER - RIO GRANDE, NEW MEXICO

    Institute of Scientific and Technical Information of China (English)

    Gigi RICHARD; Pierre JULIEN

    2003-01-01

    The impact of construction of dams and reservoirs on alluvial rivers extends both upstream and downstream of the dam. Downstream of dams, both the water and sediment supplies can be altered leading to adjustments in the river channel geometry and ensuing changes in riparian and aquatic habitats.The wealth of pre and post-regulation data on the Middle Rio Grande, New Mexico, provides an excellent case study of river regulation, channel adjustments, and restoration efforts. Cochiti Dam was constructed on the main stem of the Rio Grande in 1973 for flood control and sediment retention. Prior to dam construction, the Rio Grande was a wide, sandy braided river. Following dam construction, the downstream channel bed degraded and coarsened to gravel size, and the planform shifted to a more meandering pattern. Ecological implications of the geomorphic changes include detachment of the river from the floodplain, reduced recruitment of riparian cottonwoods, encroachment of non-native saltcedar and Russian olive into the floodplain, and degraded aquatic habitat for the Rio Grande silvery minnow.Recent restoration strategies include removal of non-native riparian vegetation, mechanical lowering of floodplain areas, and channel widening.

  17. Impact of forest type and management strategy on avian densities in the Mississippi Alluvial Valley, USA

    Science.gov (United States)

    Twedt, D.J.; Wilson, R.R.; Henne-Kerr, J.L.; Hamilton, R.B.

    1999-01-01

    Avian territory densities were determined from 20 Breeding Bird Censuses in mature (>30 years) bottomland hardwood stand: and 18 Breeding Bird Censuses in young (6-9 years old) cottonwood (Populas deltoides) plantations in the Mississippi Alluvial Valley. Avian species richness, diversity, and territory density were greater (p 0.05). Even so, detrended correspondence analysis based on avian territory densities readily segregated forest types and silvicultural treatments. Timber harvest within bottomland hardwood stands resulted in a shift in bird communities toward those found in cottonwood stands by increasing the densities of early-successional species such as Indigo Bunting (Passerina cyanea), Yellow-breasted Chat (Icteria virens), and Common Yellowthroat (Geothlypis trichas). Conversely, regenerating cottonwood stands from root sprouts, rather than planting stem cuttings, resulted in a shift in bird communities toward those found in bottomland hardwood stands by increasing densities of species such as White-eyed Vireo (Vireo griseus) and Wood Thrush (Hylocichla mustelina). Tree species diversity, angular canopy cover, and midstory density were positively associated with bird species assemblages in bottomland hardwood stands, whereas vegetation density at ground level was positively associated with bird communities in cottonwood plantations. Conversion of agricultural fields to short-rotation cottonwood plantations results in increased breeding bird populations by adding up to 140 additional territories 40 ha-1. Even so, relative conservation values, derive, from indicator species analysis and Partners in Flight concern scores, suggest that mature bottomland hardwood forests are twice as 'valuable' for bird conservation as are cottonwood plantations.

  18. Three-dimensional Modelling Of Nitrate Tranfer In A Flooded Alluvial Zone

    Science.gov (United States)

    Trémolières, M.; Lachenal, C.; Sánchez-Pérez, J. M.

    In the groundwater of a flooded alluvial forest in Alsace (Illwald forest, Eastern France), upstream of the forest nitrate concentrations (close to 40 mg/l) are largely higher than those downstream (lower than 5 mg/l). The objective of this study is to evaluate the effect of two factors which could be responsible for nitrogen elim- ination : drainage by streams and river (very significant in the area) and reduction by the groundwater U plant complex (bacterial denitrification and root uptake). A three-dimensional hydrodynamic model was used to estimate horizontal and vertical flows of water in the aquifer. The conception of this model required data of hydraulic conductivity, surface water - groundwater exchanges and nitrate concentrations. The model was validated with the three following variables, which were measured locally : piezometric level, volume exported by streams and chloride concentrations in ground- water (used as an hydrological tracer). The main results showed that the drainage by streams contributed to the elimination of polluted groundwater to a depth of at least 40 m. The balance input-output of the system was calculated acroos the whole surface (2100ha) over a period of three years. The total purifying capacity of this wetland was close to 240 kgN/ha/year and only 40kg/ha/year were eliminated by stream drainage, the greater part of the rest was eliminated by denitrification and/or root uptake.

  19. Valuing ecosystem services from wetlands restoration in the Mississippi Alluvial Valley

    Science.gov (United States)

    Jenkins, W.A.; Murray, B.C.; Kramer, R.A.; Faulkner, S.P.

    2010-01-01

    This study assesses the value of restoring forested wetlands via the U.S. government's Wetlands Reserve Program (WRP) in the Mississippi Alluvial Valley by quantifying and monetizing ecosystem services. The three focal services are greenhouse gas (GHG) mitigation, nitrogen mitigation, and waterfowl recreation. Site- and region-level measurements of these ecosystem services are combined with process models to quantify their production on agricultural land, which serves as the baseline, and on restored wetlands. We adjust and transform these measures into per-hectare, valuation-ready units and monetize them with prices from emerging ecosystem markets and the environmental economics literature. By valuing three of the many ecosystem services produced, we generate lower bound estimates for the total ecosystem value of the wetlands restoration. Social welfare value is found to be between $1435 and $1486/ha/year, with GHG mitigation valued in the range of $171 to $222, nitrogen mitigation at $1248, and waterfowl recreation at $16. Limited to existing markets, the estimate for annual market value is merely $70/ha, but when fully accounting for potential markets, this estimate rises to $1035/ha. The estimated social value surpasses the public expenditure or social cost of wetlands restoration in only 1 year, indicating that the return on public investment is very attractive for the WRP. Moreover, the potential market value is substantially greater than landowner opportunity costs, showing that payments to private landowners to restore wetlands could also be profitable for individual landowners. ?? 2009 Elsevier B.V.

  20. Sediments and processes on a small stream-flow dominated, devonian alluvial fan, Shetland Islands

    Science.gov (United States)

    Allen, Philip A.

    1981-05-01

    The main conglomerate type of a small Devonian alluvial fan in Shetland, northern Britain, is an inverse to normally graded framework-supported gravel. The sedimentological details of these beds and fundamental considerations of the mechanics of movement of highly concentrated flows suggests that neither debris-flow nor grain-flow were responsible for the deposition of these conglomerates. On the contrary, these inverse to normally graded conglomerates were deposited by water as thick gravel sheets with little topographic relief, but broadly analogous to longitudinal bars. They were deposited under high aggradation conditions first on the rising and then on the falling flood. The high concentration of material in transport on the rising and peak flood was responsible for the polymodal and unstratified nature of the conglomerates. As the flood waned, normal grading was developed and a preferred horizontal fabric was produced under low concentrations of sediment. Other conglomerate types, comparatively of lesser importance, were deposited from highly concentrated clast dispersions and are notably richer in matrix and locally possess inverse grading. The hydrological environment was one of flashy discharges of short duration but of high velocity. Flow was dissipated rapidly, perhaps due to extreme water loss. This example from the Devonian of Shetland provides an interesting alternative to the mass-transport dominated fan models currently in vogue.

  1. Radial mosaic internal structure of rounded diamond crystals from alluvial placers of Siberian platform

    Science.gov (United States)

    Ragozin, A. L.; Zedgenizov, D. A.; Kuper, K. E.; Shatsky, V. S.

    2016-12-01

    The specific gray to almost black diamonds of rounded morphology are especially typical in alluvial placers of the northeastern part of the Siberian platform. The results of study of internal structure of these diamonds are presented. X-ray topography and birefringence patterns of polished plates of studied diamonds show their radial mosaic structure. Diamonds consists of slightly misorientated (up to 20') subindividuals which are combined to mosaic wedge-shaped sectors. Electron back-scatter diffraction technique has demonstrated that subindividuals are often combined in the single large blocks (subgrains). The whole crystals commonly consist of several large subgrains misoriented up to 5° to one another. The total nitrogen content of these diamonds vary in the range 900-3300 ppm and nitrogen aggregation state (NB/(NB + NA)*100) from 25 to 64 %. Rounded diamond crystals of variety V are suggested to have been formed at the high growth rate caused by the high oversaturation of carbon in the crystallization medium. It may result in the splitting of growing crystal and their radial mosaic structure as a sequence. High content of structural nitrogen defects and the great number of mechanical impurities - various mineral and fluid inclusions may also favor to generation of this structure.

  2. Geomorphic and hydrodynamic responses of experimental alluvial channels to rigid vegetation

    Science.gov (United States)

    Bennett, S. J.

    2009-05-01

    Vegetation such as trees and woody debris remains a key component of bank stabilization and stream restoration programs because of the beneficial ecologic and hydraulic effects and attributes it brings to river corridors. Yet few design criteria currently are available to guide the use and application of these activities, and part of this problem may lie in not knowing precisely how river corridors respond to the newly introduced vegetation. Physical experiments provide the unambiguous quantification of the geomorphic, hydraulic, and hydrodynamic responses of alluvial channels to the introduction of vegetation. To this end, a range of physical experiments have been conducted using simulated stands of rigid, emergent vegetation and submerged large woody debris in both fixed- and mobile-bed channels to identify these geomorphic responses to and hydrodynamic effects of the introduced vegetation. Experimental results will focus on flow resistance, secondary flow and meander development, coherent flow structures and turbulent mixing, localized erosion and deposition, and the potential for nutrient retention, all in relation to the size, shape, orientation, and density of managed plantings of vegetation or the placement of large woody debris. These experimental results will be compared to both theory and numerical models, and will be discussed within the context of stream restoration design.

  3. Application of Large-Scale Inversion Algorithms to Hydraulic Tomography in an Alluvial Aquifer.

    Science.gov (United States)

    Fischer, P; Jardani, A; Soueid Ahmed, A; Abbas, M; Wang, X; Jourde, H; Lecoq, N

    2017-03-01

    Large-scale inversion methods have been recently developed and permitted now to considerably reduce the computation time and memory needed for inversions of models with a large amount of parameters and data. In this work, we have applied a deterministic geostatistical inversion algorithm to a hydraulic tomography investigation conducted in an experimental field site situated within an alluvial aquifer in Southern France. This application aims to achieve a 2-D large-scale modeling of the spatial transmissivity distribution of the site. The inversion algorithm uses a quasi-Newton iterative process based on a Bayesian approach. We compared the results obtained by using three different methodologies for sensitivity analysis: an adjoint-state method, a finite-difference method, and a principal component geostatistical approach (PCGA). The PCGA is a large-scale adapted method which was developed for inversions with a large number of parameters by using an approximation of the covariance matrix, and by avoiding the calculation of the full Jacobian sensitivity matrix. We reconstructed high-resolution transmissivity fields (composed of up to 25,600 cells) which generated good correlations between the measured and computed hydraulic heads. In particular, we show that, by combining the PCGA inversion method and the hydraulic tomography method, we are able to substantially reduce the computation time of the inversions, while still producing high-quality inversion results as those obtained from the other sensitivity analysis methodologies.

  4. Free Oxide Distribution in Poorly and Well Drained Soils Developed on Calcareous Alluvial Deposits

    Institute of Scientific and Technical Information of China (English)

    N. K. MOUSTAKAS; P. E. BAROUCHAS

    2003-01-01

    A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.

  5. Influence of hydrologic modifications on Fraxinus pennsylvanica in the Mississippi River Alluvial Valley, USA

    Science.gov (United States)

    Gee, Hugo K.W.; King, Sammy L.; Keim, Richard F.

    2015-01-01

    We used tree-ring analysis to examine radial growth response of a common, moderately flood-tolerant species (Fraxinus pennsylvanica Marshall) to hydrologic and climatic variability for > 40 years before and after hydrologic modifications affecting two forest stands in the Mississippi River Alluvial Valley (USA): a stand without levees below dams and a stand within a ring levee. At the stand without levees below dams, spring flood stages decreased and overall growth increased after dam construction, which we attribute to a reduction in flood stress. At the stand within a ring levee, growth responded to the elimination of overbank flooding by shifting from being positively correlated with river stage to not being correlated with river stage. In general, growth in swales was positively correlated with river stage and Palmer Drought Severity Index (an index of soil moisture) for longer periods than flats. Growth decreased after levee construction, but swales were less impacted than flats likely because of differences in elevation and soils provide higher soil moisture. Results of this study indicate that broad-scale hydrologic processes differ in their effects on the flood regime, and the effects on growth of moderately flood-tolerant species such as F. pennsylvanica can be mediated by local-scale factors such as topographic position, which affects soil moisture.

  6. Analysis of managed aquifer recharge for retiming streamflow in an alluvial river

    Science.gov (United States)

    Ronayne, Michael J.; Roudebush, Jason A.; Stednick, John D.

    2017-01-01

    Maintenance of low flows during dry periods is critical for supporting ecosystem function in many rivers. Managed aquifer recharge is one method that can be used to augment low flows in rivers that are hydraulically connected to an alluvial groundwater system. In this study, we performed numerical modeling to evaluate a managed recharge operation designed to retime streamflow in the South Platte River, northeastern Colorado (USA). Modeling involved the simulation of spatially and temporally variable groundwater-surface water exchange, as well as streamflow routing in the river. Periodic solutions that incorporate seasonality were developed for two scenarios, a natural base case scenario and an active management scenario that included groundwater pumping and managed recharge. A framework was developed to compare the scenarios by analyzing changes in head-dependent inflows and outflows to/from the aquifer, which was used to interpret the simulated impacts on streamflow. The results clearly illustrate a retiming of streamflow. Groundwater pumping near the river during winter months causes a reduction in streamflow during those months. Delivery of the pumped water to recharge ponds, located further from the river, has the intended effect of augmenting streamflow during low-flow summer months. Higher streamflow is not limited to the target time period, however, which highlights an inefficiency of flow augmentation projects that rely on water retention in the subsurface.

  7. Modeling chloride movement in the alluvial aquifer at the Rocky Mountain Arsenal, Colorado

    Science.gov (United States)

    Konikow, Leonard F.

    1977-01-01

    A solute-transport model that can be used to predict the movement of dissolved chemicals in flowing ground water was applied to a problem of ground-water contamination at the Rocky Mountain Arsenal, near Denver, Colo. The model couples a finite-difference solution to the ground-water flow equation with the method-of-characteristics solution to the solute-transport equation. From 1943 to 1956 liquid industrial wastes containing high chloride concentrations were disposed into unlined ponds at the Arsenal. Wastes seeped out of the unlined disposal ponds and spread for many square miles in the underlying shallow alluvial aquifer. Since 1956 disposal has been into an asphalt-lined reservoir, which contributed to a decline in ground-water contamination by 1972. The simulation model quantitatively integrated the effects of the major factors that controlled changes in chloride concentrations and accurately reproduced the 30-year history of chloride ground-water contamination. Analysis of the simulation results indicates that the geologic framework of the area markedly restricted the transport and dispersion of dissolved chemicals in the alluvium. Dilution, from irrigation recharge and seepage from unlined canals, was an important factor in reducing the level of chloride concentrations downgradient from the Arsenal. Similarly, recharge of uncontaminated water from the unlined ponds since 1956 has helped to dilute and flush the contaminated ground water.

  8. Hydrogeological typologies of the Indo-Gangetic basin alluvial aquifer, South Asia

    Science.gov (United States)

    Bonsor, H. C.; MacDonald, A. M.; Ahmed, K. M.; Burgess, W. G.; Basharat, M.; Calow, R. C.; Dixit, A.; Foster, S. S. D.; Gopal, K.; Lapworth, D. J.; Moench, M.; Mukherjee, A.; Rao, M. S.; Shamsudduha, M.; Smith, L.; Taylor, R. G.; Tucker, J.; van Steenbergen, F.; Yadav, S. K.; Zahid, A.

    2017-02-01

    The Indo-Gangetic aquifer is one of the world's most important transboundary water resources, and the most heavily exploited aquifer in the world. To better understand the aquifer system, typologies have been characterized for the aquifer, which integrate existing datasets across the Indo-Gangetic catchment basin at a transboundary scale for the first time, and provide an alternative conceptualization of this aquifer system. Traditionally considered and mapped as a single homogenous aquifer of comparable aquifer properties and groundwater resource at a transboundary scale, the typologies illuminate significant spatial differences in recharge, permeability, storage, and groundwater chemistry across the aquifer system at this transboundary scale. These changes are shown to be systematic, concurrent with large-scale changes in sedimentology of the Pleistocene and Holocene alluvial aquifer, climate, and recent irrigation practices. Seven typologies of the aquifer are presented, each having a distinct set of challenges and opportunities for groundwater development and a different resilience to abstraction and climate change. The seven typologies are: (1) the piedmont margin, (2) the Upper Indus and Upper-Mid Ganges, (3) the Lower Ganges and Mid Brahmaputra, (4) the fluvially influenced deltaic area of the Bengal Basin, (5) the Middle Indus and Upper Ganges, (6) the Lower Indus, and (7) the marine-influenced deltaic areas.

  9. Sedimentology and clast fabric of subaerial debris flow facies in a glacially-influenced alluvial fan

    Science.gov (United States)

    Eyles, N.; Kocsis, S.

    1988-09-01

    A large alluvial fan (2 km 2), constructed between 11,000 and 7000 years B.P. at the mouth of Cinquefoil Creek in interior British Columbia, Canada, is identified as "glacially-influenced, debris flow-dominated". The fan was rapidly constructed during and immediately after deglaciation when large volumes of glacial debris were resedimented downslope; fans of this type are widespread in the glaciated portion of the North American Cordillera. Diamict facies, deposited as debris flows, account for 48% of the fan volume, sheetflodd gravels 37%, and other facies 15%. Diamicts show three facies types; crudely-bedded facies containing rafts of soft sediment that are attributed to downslope collapse and mixing of heterogeneous glacial deposits. These occur within the core of the fan. Massive and weakly graded (inverse to normal) diamict facies, derived from the downslope flow of weathered volcanic bedrock, occur within a well-defined bed that can be traced across the entire fan. The occurrence of weakly graded facies as lateral equivalents to massive facies within the same bed, implies the partial development of turbulent, high-velocity "streams" within a viscous debris flow moving over a slope of 6°. Clast fabrics in these facies show weakly-clustered a-axes dipping up and downslope comparable to other debris flows and lahars. The Cinquefoil fan, its internal structure and facies, provides a good "modern" analogue for ancient diamictite sequences deposited in areas of active uplift, rifting and glaciation.

  10. Nocturnal insect availability in bottomland hardwood forests managed for wildlife in the Mississippi Alluvial Valley

    Science.gov (United States)

    Loraine Ketzler,; Christopher Comer,; Twedt, Daniel J.

    2017-01-01

    Silviculture used to alter forest structure and thereby enhance wildlife habitat has been advocated for bottomland hardwood forest management on public conservation lands in the Mississippi Alluvial Valley. Although some songbirds respond positively to these management actions to attain desired forest conditions for wildlife, the response of other species, is largely unknown. Nocturnal insects are a primary prey base for bats, thereby influencing trophic interactions within hardwood forests. To better understand how silviculture influences insect availability for bats, we conducted vegetation surveys and sampled insect biomass within silviculturally treated bottomland hardwood forest stands. We used passive blacklight traps to capture nocturnal flying insects in 64 treated and 64 untreated reference stands, located on 15 public conservation areas in Arkansas, Louisiana, and Mississippi. Dead wood and silvicultural treatments were positively associated with greater biomass of macro-Lepidoptera, macro-Coleoptera, and all insect taxa combined. Biomass of micro-Lepidoptera was negatively associated with silvicultural treatment but comprised only a small proportion of total biomass. Understanding the response of nocturnal insects to wildlife-forestry silviculture provides insight for prescribed silvicultural management affecting bat species.

  11. Liquefaction analysis of alluvial soil deposits in Bedsa south west of Cairo

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2014-09-01

    Full Text Available Bedsa is one of the districts in Dahshour that lays south west of Cairo and suffered from liquefaction during October 1992 earthquake, Egypt. The soil profile consists of alluvial river Nile deposits mainly sandy mud with low plasticity; the ground water is shallow. The earthquake hypocenter was 18 km far away with local magnitude 5.8; the fault length was 13.8 km, as recorded by the Egyptian national seismological network (ENSN at Helwan. The analysis used the empirical method introduced by the national center for earthquake engineering research (NCEER based on field standard penetration of soil. It is found that the studied area can liquefy since there are saturated loose sandy silt layers at depth ranges from 7 to 14 m. The settlement is about 26 cm. The probability of liquefaction ranges between 40% and 100%. The presence of impermeable surface from medium cohesive silty clay acts as a plug resisting and trapping the upward flow of water during liquefaction, so fountain and spouts at weak points occurs. It is wise to use point bearing piles with foundation level deeper than 14 m beyond the liquefiable depth away from ground slopes, otherwise liquefaction improving techniques have to be applied in the area.

  12. Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment

    Directory of Open Access Journals (Sweden)

    K. Edmaier

    2011-05-01

    Full Text Available The establishment of riparian pioneer vegetation is of crucial importance within river restoration projects. After germination or vegetative reproduction on river bars juvenile plants are often exposed to mortality by uprooting caused by floods. At later stages of root development vegetation uprooting by flow is seen to occur as a consequence of a marked erosion gradually exposing the root system and accordingly reducing the mechanical anchoring. How time scales of flow-induced uprooting do depend on vegetation stages growing in alluvial non-cohesive sediment is currently an open question that we conceptually address in this work. After reviewing vegetation root issues in relation to morphodynamic processes, we then propose two modelling mechanisms (Type I and Type II, respectively concerning the uprooting time scales of early germinated and of mature vegetation. Type I is a purely flow-induced drag mechanism, which causes alone a nearly instantaneous uprooting when exceeding root resistance. Type II arises as a combination of substantial sediment erosion exposing the root system and resulting in a decreased anchoring resistance, eventually degenerating into a Type I mechanism. We support our conceptual models with some preliminary experimental data and discuss the importance of better understanding such mechanisms in order to formulate sounding mathematical models that are suitable to plan and to manage river restoration projects.

  13. The affect of industrial activities on zinc in alluvial Egyptian soil determined using neutron activation analysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thirty-two surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted,moderately and highly polluted soils.The aim of this study was to evaluate total Zn content in alluvial soils of Nile Delta in Egypt by using the delayed neutron activation analysis technique (DNAA),in the irradiation facilities of the first Egyptian research reactor (ET-RR-1).The gamma-ray spectra were recorded with a hyper pure germanium detection system.The well resolved gamma-ray peak at 1116.0 kev was efficiently used for 65Zn content determination.Zn content in non-polluted soil samples ranged between 74.1 and 103.8 ppm with an average of 98.5 + 5.1 ppm.Zn content in moderately polluted soils ranged between 136.0 and 232.5 ppm with an average of 180.1 + 32.6 ppm.The highest Zn levels ranging from 240.0 and 733.0 ppm with an average of 410.3 + 54.4 ppm,were observed in soil samples collected from,either highly polluted agricultural soils exposed to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  14. The affect of industrial activities on zinc in alluvial Egyptian soil determined using neutron activation analysis.

    Science.gov (United States)

    Abdel-Sabour, M F; Abdel-Basset, N

    2002-07-01

    Thirty-two surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted, moderately and highly polluted soils. The aim of this study was to evaluate total Zn content in alluvial soils of Nile Delta in Egypt by using the delayed neutron activation analysis technique (DNAA), in the irradiation facilities of the first Egyptian research reactor (ET-RR-1). The gamma-ray spectra were recorded with a hyper pure germanium detection system. The well resolved gamma-ray peak at 1116.0 keV was efficiently used for 65Zn content determination. Zn content in non-polluted soil samples ranged between 74.1 and 103.8 ppm with an average of 98.5 +/- 5.1 ppm. Zn content in moderately polluted soils ranged between 136.0 and 232.5 ppm with an average of 180.1 +/- 32.6 ppm. The highest Zn levels ranging from 240.0 and 733.0 ppm with an average of 410.3 +/- 54.4 ppm, were observed in soil samples collected from, either highly polluted agricultural soils exposed to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

  15. Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

    Science.gov (United States)

    Madole, Richard F.

    2012-01-01

    Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~2450–1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~1 m) incision. Published

  16. Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

    Science.gov (United States)

    Madole, Richard F.

    2012-09-01

    Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~ 2450-1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~ 1 m) incision.

  17. Lithology, hydrologic characteristics, and water quality of the Arkansas River Valley alluvial aquifer in the vicinity of Van Buren, Arkansas

    Science.gov (United States)

    Kresse, Timothy M.; Westerman, Drew A.; Hart, Rheannon M.

    2015-01-01

    A study to assess the potential of the Arkansas River Valley alluvial aquifer in the vicinity of Van Buren, Arkansas, as a viable source of public-supply water was conducted by the U.S. Geological Survey in cooperation with the Little Rock, District, U.S. Army Corps of Engineers. An important study component was to identify possible changes in hydrologic conditions following installation of James W. Trimble Lock and Dam 13 (December 1969) on the Arkansas River near the study area. Data were gathered for the study in regard to the lithology, hydrologic characteristics, and water quality of the aquifer. Lithologic information was obtained from drillers’ logs of wells drilled from 1957 through 1959. Water-quality samples were collected from 10 irrigation wells and analyzed for inorganic constituents and pesticides. To evaluate the potential viability of the alluvial aquifer in the Van Buren area, these data were compared to similar stratigraphic, lithologic, and groundwater-quality data from the Arkansas River Valley alluvial aquifer at Dardanelle, Ark., where the aquifer provides a proven, productive, sole-source of public-supply water.

  18. Facet tropism: comparison of plain film and computed tomography examinations.

    Science.gov (United States)

    Cox, J M; Aspegren, D D; Trier, K K

    1991-01-01

    This study compares the findings of plain film X-ray and computed CT examination in the diagnosis of facet orientation and the presence of tropism. Twenty consecutive patients having lumbar disc disease with sciatica were studied utilizing plain X-ray as well as CT scanning. A chiropractic radiologist read the films to determine if facet facings were sagittally, semi-sagittally or coronally oriented on both CT and plain X-ray study. CT was accepted as the most accurate method to determine the true facet orientation, and plain X-ray interpretation of facet orientation was compared to the CT reading. There was a statistically significant relationship in diagnosing tropism between plain film X-ray and CT readings, with a predictive accuracy that ranged from 58-84% across the three segmental levels. However, the exact concordance of plain film X-ray and CT readings for right and left facet facings was very low. This raises the question of how the profession defines diagnostic accuracy.

  19. Gravel deposit produced by a flash paleoflood in a succession of Quaternary terraces in the Plain of Vic (NE Iberian Peninsula)

    Science.gov (United States)

    Castelltort, Xavier; Colombo, Ferran; Carles Balasch, Josep; Barriendos, Mariano; Mazón, Jordi; Pino, David; Lluís Ruiz-Bellet, Josep; Tuset, Jordi

    2016-04-01

    In contrast with the abundance of studies of fluvial terraces, caused by river dynamics, there are very few descriptions of alluvial deposits produced by flash floods and mass movements. This study describes a late Pleistocene sedimentary deposit produced by a flash paleoflood and attempts to explain its genesis and its source areas. The Plain of Vic, drained by the river Ter and its tributaries, is one of the eastern erosive basins bordering the sedimentary Ebre basin (NE Iberian Peninsula). This plain has a length of 35 km and an average width of 8 km with a N-S direction and lies mainly on the Marls of Vic Fm. These materials are the less resistant lithologic members of the monocline Paleogene stratigraphic succession that dips to the west. The basal resistant bed that forms the eastern cuesta is the Sandstones of Folgueroles Fm. On the top, the resistant lithologic beds that form the scarp face are the sandstones of La Noguera in the Vidrà Fm. On the scarp face, various coalescent alluvial bays have been developed, which have accumulated up to eight levels of alluvial terraces. In one of them, formed by the river Mèder and the Muntanyola stream, a gravel deposit up to 5 m thick formed in a single episode outcrops, in a position T4,. A dating of the river Ter T5 has obtained an age of 117.9 ± 9.5 Ky. The accumulation of gravel erodes another level of metric thickness of the same lithological characteristics and texture. The deposit does not have any internal structure or organization of pebbles. At its base, there are several metric blocks coming directly from the slopes. The accumulation of gravel is block-supported with a sandy matrix. The pebbles size is centimetric to decimetric (90%). Its texture is subrounded. Lithologically, the deposit consists mostly of sandstone and limestone from the top of the series. On the ground, the accumulation of gravel is elongated, with a maximum length and width of 550 m by 160 m and a slope surface of 2.54%. With an area

  20. PLAINS CO2 REDUCTION (PCOR) PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Edward N. Steadman; Daniel J. Daly; Lynette L. de Silva; John A. Harju; Melanie D. Jensen; Erin M. O' Leary; Wesley D. Peck; Steven A. Smith; James A. Sorensen

    2006-01-01

    During the period of October 1, 2003, through September 30, 2005, the Plains CO2 Reduction (PCOR) Partnership, identified geologic and terrestrial candidates for near-term practical and environmentally sound carbon dioxide (CO2) sequestration demonstrations in the heartland of North America. The PCOR Partnership region covered nine states and three Canadian provinces. The validation test candidates were further vetted to ensure that they represented projects with (1) commercial potential and (2) a mix that would support future projects both dependent and independent of CO2 monetization. This report uses the findings contained in the PCOR Partnership's two dozen topical reports and half-dozen fact sheets as well as the capabilities of its geographic information system-based Decision Support System to provide a concise picture of the sequestration potential for both terrestrial and geologic sequestration in the PCOR Partnership region based on assessments of sources, sinks, regulations, deployment issues, transportation, and capture and separation. The report also includes concise action plans for deployment and public education and outreach as well as a brief overview of the structure, development, and capabilities of the PCOR Partnership. The PCOR Partnership is one of seven regional partnerships under Phase I of the U.S. Department of Energy National Energy Technology Laboratory's Regional Carbon Sequestration Partnership program. The PCOR Partnership, comprising 49 public and private sector members, is led by the Energy & Environmental Research Center at the University of North Dakota. The international PCOR Partnership region includes the Canadian provinces of Alberta, Saskatchewan, and Manitoba and the states of Montana (part), Wyoming (part), North Dakota, South Dakota, Nebraska, Missouri, Iowa, Minnesota, and Wisconsin.

  1. Alluvial-eolian interaction in a Cambrian rift margin: the Pedra das Torrinhas and Pedra Pintada formations (Guaritas Group, RS

    Directory of Open Access Journals (Sweden)

    André Marconato

    2009-12-01

    Full Text Available This work presents a study of selected outcrops from the Pedra das Torrinhas Formation of the Guaritas Group (Cambrian, Camaquã Basin, near the basin bordering Encantadas Fault Zone. The studied succession includes alluvial fan deposits that pass laterally into eolian deposits. Sedimentary facies and architectural element analysis were performed, followed by sedimentary petrography and microscopic porosity analysis, aiming to characterize the porosity of the deposits and its spatial distribution. The main objective was to contribute to a better understanding of the porosity spatial distribution in depositional systems characterized by the interaction between alluvial and eolian processes, with special reference to deposits formed prior to the development of terrestrial plants. Porosity values are related to depositional processes, with higher porosities associated to eolian dune deposits (mean of 8.4%, and lower porosity related to interdunes (mean of 3.4% and alluvial fans (mean of 4.3%. Architectural elements analysis revealed the spatial relationships of these deposits, a response to the interplay of the eolian and alluvial processes. The integration of porosity data reveals that the interaction of alluvial and eolian processes results in heterogeneous distribution of porosity at the facies association scale. Eolian reworking of alluvial facies increases porosity whereas sheet-flood and other alluvial processes in the interdune areas reduce porosity.O presente trabalho consiste no estudo de afloramentos da Formação Pedra das Torrinhas do Grupo Guaritas (Cambriano, Bacia Camaquã, próximo à Zona de Falha das Encantadas. As sucessões estudadas incluem depósitos de leques aluviais que passam lateralmente para depósitos eólicos. Foram realizadas análises de fácies e de elementos arquiteturais, seguidos de petrografia sedimentar e análise microscópica de porosidade, com o objetivo de caracterizar a porosidade da unidade e sua

  2. Radar facies and architecture of alluvial fans and related sediments in high-energy alpine environments, British Columbia

    Science.gov (United States)

    Ekes, Csaba

    2000-08-01

    It is widely recognized that the dominant depositional processes on alluvial fans include rock falls, rock slides, rock avalanches, debris flows, sheetfloods and incised-channel floods. A fundamental question addressed in this thesis is: Can ground penetrating radar (GPR) differentiate between the sediments associated with these processes? Do these individual deposits have characteristic radar reflection signatures? The dissertation is divided into two parts. In part one, a calibration exercise conducted in southern British Columbia, it was demonstrated that GPR was able to obtain good penetration and resolution in rock fall, rock slide, fluvial and alluvial fan sediments, and that a characteristic radar reflection pattern (or radar facies) can be assigned to these deposits. Bedrock reflection pattern is characterised by a discontinuous radar signal and by stacked diffractions. The radar facies for rock slide and rock avalanche sediments, where boulders constitute the predominant clast size, is characterized by discontinuous, high amplitude, macro-scale, hyperbolic reflections that are different from diffractions generated by bedrock. Alluvial fans dominated by debris flow processes produce a chaotic and discontinuous radar pattern; diffractions in these patterns are attributed to boulders. Alluvial fans dominated by sheetflood processes are likely to produce surface-parallel, gently dipping, more or less continuous radar patterns. Large-scale meandering-river radar-patterns are characterized by high amplitude, continuous, dipping clinoforms. Braided-river radar facies, based on data collected on the Kicking Horse braidplain, are characterized by predominantly horizontally continuous reflections with few identifiable features. Based solely on GPR data, it was possible to distinguish between sediments of meandering and braided rivers. Analysis of over 95 km GPR data suggests that alluvial fan radar-reflection patterns are distinctly different from those observed in

  3. Plain packaging of cigarettes: do we have sufficient evidence?

    Directory of Open Access Journals (Sweden)

    Smith CN

    2015-04-01

    Full Text Available Collin N Smith,1 John D Kraemer,2 Andrea C Johnson,1 Darren Mays1 1Department of Oncology, Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC, USA; 2Department of Health Systems Administration, School of Nursing and Health Studies, Georgetown University, Washington, DC, USA Abstract: Tobacco industry marketing is a primary factor influencing cigarette smoking behavior and the cigarette pack has become an important marketing vehicle for tobacco companies. Standardized “plain” cigarette packaging is advocated as a public health policy to prevent and reduce morbidity and mortality caused by smoking by reducing youth smoking initiation and promoting cessation among smokers. Plain packaging was implemented in Australia in December 2012, and several other countries are considering doing so, but each faces foreseeable legal resistance from opponents to such measures. Tobacco companies have challenged these public health policies, citing international trade agreements and intellectual property laws. Decision-making in these court cases will hinge in part on whether the evidence indicates the public health benefits of plain packaging outweigh any potential harm to tobacco manufacturers’ interests. We reviewed the available evidence in support of plain packaging, finding evidence from observational, experimental, and population-based studies. Results indicate that plain packaging can reduce positive perceptions of smoking and dissuade tobacco use. Governments deciding to implement plain cigarette packaging measures can rely on this evidence to help make a strong case that plain packaging plays an important role in the context of comprehensive smoking prevention efforts. Keywords: cigarette smoking, tobacco, plain packaging, regulation, policy

  4. Modelling the Holocene Evolution of a Drift-dominated Alluvial-fan Coast

    Science.gov (United States)

    Hicks, M.; Dickson, M.; Coco, G.

    2007-12-01

    A numerical model is being developed to simulate shore evolution along an alluvial fan coast over the Holocene. The alluvial fan of the Waitaki River, on the east coast of New Zealand's South Island, was built by Pleistocene glacial advances but has been eroded back by waves over recent millennia. The retreat has left a cliffed shore fronted by a narrow beach of mixed sand and gravel and a gently sloping seabed with only a thin, patchy sand cover over the Pleistocene substrate. The study motivation is to examine the sensitivity of shoreline movements in this setting to wave-climate change, sea-level rise, and river sediment supplies. The modelling couples a profile evolution model with a shoreline model. The profile evolution model is operational and is driven by a series of coupled process models which include seabed scour, berm construction during normal waves, berm overtopping and subsequent beach-stripping and scour of the exposed substrate and cliff-toe notching by storm waves, gravity failure of the cliffs and talus construction, and beach sediment abrasion. Negative feedback regulates the rate of cliff erosion through the protection provided by the new material added into the beach from the eroding cliffs and substrate. The model is forced by two wave conditions: a normal swell and a randomly-varying storm wave. These operate for proportions of the yearly time step. The model was begun on a sloping fan surface inundated by the last stages of post-glacial sea-level rise (8000 yr BP). The initial response is for rapid growth of a gravel beach ridge fed by wave-excavation of the nearshore. As the nearshore profile nears equilibrium with the wave climate, the onshore feed wanes below the abrasion rate and the beach ridge loses volume. As sea level rises the beach ridge moves upward and landward, but its capacity to do so is limited by the rate of sediment feed from the nearshore. When the beach size reduces to a threshold at which storm waves periodically

  5. The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona

    Science.gov (United States)

    Pool, D.R.

    2008-01-01

    Coincident monitoring of gravity and water levels at 39 wells in southern Arizona indicate that water-level change might not be a reliable indicator of aquifer-storage change for alluvial aquifer systems. One reason is that water levels in wells that are screened across single or multiple aquifers might not represent the hydraulic head and storage change in a local unconfined aquifer. Gravity estimates of aquifer-storage change can be approximated as a one-dimensional feature except near some withdrawal wells and recharge sources. The aquifer storage coefficient is estimated by the linear regression slope of storage change (estimated using gravity methods) and water-level change. Nonaquifer storage change that does not percolate to the aquifer can be significant, greater than 3 ??Gal, when water is held in the root zone during brief periods following extreme rates of precipitation. Monitor-ing of storage change using gravity methods at wells also can improve understanding of local hydrogeologic conditions. In the study area, confined aquifer conditions are likely at three wells where large water-level variations were accompanied by little gravity change. Unconfined conditions were indicated at 15 wells where significant water-level and gravity change were positively linearly correlated. Good positive linear correlations resulted in extremely large specific-yield values, greater than 0.35, at seven wells where it is likely that significant ephemeral streamflow infiltration resulted in unsaturated storage change. Poor or negative linear correlations indicate the occurrence of confined, multiple, or perched aquifers. Monitoring of a multiple compressible aquifer system at one well resulted in negative correlation of rising water levels and subsidence-corrected gravity change, which suggests that water-level trends at the well are not a good indicatior of overall storage change. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

  6. Assessment of spatial flow patterns in unsaturated sandy alluvial sediments using high- resolution GPR.

    Science.gov (United States)

    Haarder, E. B.; Looms, M. C.; Nielsen, L.; Jensen, K. H.

    2008-12-01

    Traditional sampling and monitoring techniques have inherent limitations in capturing the detailed spatial patterns of water flow in the unsaturated zone particularly for complex flow conditions such as unstable wetting fronts or preferential flow. Dye tracer experiments can help visualise the dynamics of water flow but they are highly destructive as well. High-resolution Ground Penetrating Radar (GPR) is an attractive technique for non-destructive mapping of soil moisture changes and thus flow patterns in the shallow subsurface. In this study we test the method at a field site in western Denmark developed on a sandy alluvial outwash plane. We compare high-resolution reflection GPR data with visual observations from a dye tracer experiment using Brilliant Blue (BB). 100 mm of BB-stained water was infiltrated over a 5x5 m area and 3D reflection GPR data sets using high-frequency antennae were collected before and after infiltration. Subsequently a 2 m deep trench was excavated for visual observations of the flow patterns in a cross-section as evidenced by the dye staining patterns. The dye infiltration experiment had an overall attenuating effect on the GPR signal, and reflections were delayed significantly because of the increase in soil moisture. In the excavated cross-section we found a reasonable agreement between the areas subject to attenuation of the GPR signal and the areas affected by dye. Also, we found that displacement flow was responsible for a delay of deeper reflections below the extend of the dye staining. An amplitude analysis performed for a shallow 1.3 m thick section shows a general decrease in electromagnetic wave amplitude within the region bounded by the area exposed to infiltration, but also suggests that lateral flow along sedimentary boundaries occurs. The results suggest that high-resolution GPR provides important insight into the spatial patterns of unsaturated flow and highlight the applicability of this method as a non-destructive means

  7. Physical context for theoretical approaches to sediment transport magnitude-frequency analysis in alluvial channels

    Science.gov (United States)

    Sholtes, Joel; Werbylo, Kevin; Bledsoe, Brian

    2014-10-01

    Theoretical approaches to magnitude-frequency analysis (MFA) of sediment transport in channels couple continuous flow probability density functions (PDFs) with power law flow-sediment transport relations (rating curves) to produce closed-form equations relating MFA metrics such as the effective discharge, Qeff, and fraction of sediment transported by discharges greater than Qeff, f+, to statistical moments of the flow PDF and rating curve parameters. These approaches have proven useful in understanding the theoretical drivers behind the magnitude and frequency of sediment transport. However, some of their basic assumptions and findings may not apply to natural rivers and streams with more complex flow-sediment transport relationships or management and design scenarios, which have finite time horizons. We use simple numerical experiments to test the validity of theoretical MFA approaches in predicting the magnitude and frequency of sediment transport. Median values of Qeff and f+ generated from repeated, synthetic, finite flow series diverge from those produced with theoretical approaches using the same underlying flow PDF. The closed-form relation for f+ is a monotonically increasing function of flow variance. However, using finite flow series, we find that f+ increases with flow variance to a threshold that increases with flow record length. By introducing a sediment entrainment threshold, we present a physical mechanism for the observed diverging relationship between Qeff and flow variance in fine and coarse-bed channels. Our work shows that through complex and threshold-driven relationships sediment transport mode, channel morphology, flow variance, and flow record length all interact to influence estimates of what flow frequencies are most responsible for transporting sediment in alluvial channels.

  8. Mapping groundwater renewability using age data in the Baiyang alluvial fan, NW China

    Science.gov (United States)

    Huang, Tianming; Pang, Zhonghe; Li, Jie; Xiang, Yong; Zhao, Zhijiang

    2017-01-01

    Groundwater age has been used to map renewability of water resources within four groups: strong, partial, and rare renewability, and non-renewable. The Baiyang alluvial fan in NW China is a representative area for examining groundwater recharge from river infiltration and for mapping groundwater renewability, and it has been investigated using multiple isotopes and water chemistry. Systematic sampling included 52 samples for 2H and 18O analysis and 32 samples for 3H, 13C and 14C analysis. The δ13C compositions remain nearly constant throughout the basin (median -12.7‰) and indicate that carbonate dissolution does not alter 14C age. The initial 14C activity of 80 pmC, obtained by plotting 3H and 14C activity, was used to correct groundwater 14C age. The results show that areas closer to the river consist of younger groundwater ages; this suggests that river infiltration is the main recharge source to the shallow groundwater system. However, at distances far away from the river, groundwater ages become older, i.e., from modern water (less than 60 year) to pre-modern water (from 60 to 1,000 years) and paleowater (more than 1,000 yeas). The four classifications of groundwater renewability have been associated with different age ranges. The area of shallow groundwater with strong renewability accounts for 74% of the total study area. Because recharge condition (river infiltration) controls overall renewability, a groundwater renewability map is of significant importance to the management of groundwater exploitation of this area as well as other arid groundwater basins.

  9. Plucking in Mixed Alluvial-Bedrock Rivers: The Incipient Motion Problem

    Science.gov (United States)

    Hurst, A. A.; Furbish, D. J.

    2015-12-01

    Bedrock river channel erosion is an important factor in the evolution of landscapes, driving the relief of mountainous drainage basins and setting the lowest erosional positions of terrestrial landscapes. The mechanics behind erosional processes (predominantly plucking and abrasion) in these rivers are only recently being explored in depth. Plucking, the fracture and extraction of jointed blocks, is observationally an order of magnitude more efficient than abrasion, but if a river cannot provide the force necessary to move the plucked block, erosion by plucking cannot proceed. Therefore, incipient motion of blocks starting at rest on a solid surface is an important factor in erosion by plucking. Calculations of forces necessary for incipient motion require values of drag coefficients, which do not exist for bedrock contact geometry. We discovered from experiments on a flume that drag coefficients (CD) are inversely proportional to aspect ratios (RA), defined as the frontal block height to width. We used the relationship with field data from plucked blocks at a stream at Montgomery Bell State Park in Burns, TN, a mixed-alluvial bedrock channel with an actively incising knick zone, to support our theory and experimental data. Sizes of plucked blocks were compared to the velocities needed to move them, and then calculations done for bankfull velocities at the stream at Montgomery Bell to determine if it could attain these velocities. It was discovered that this stream has a bankfull depth-averaged velocity of 1.26 m s-1 and is capable of moving a large range of plucked block sizes. Therefore, erosion of this particular stream is plucking-limited, not transport-limited.

  10. Single application of Sewage Sludge to an Alluvial Agricultural Soil - impacts on Soil Quality

    Science.gov (United States)

    Suhadolc, M.; Graham, D. B.; Hagn, A.; Doerfler, U.; Schloter, M.; Schroll, R.; Munch, J. C.; Lobnik, F.

    2009-04-01

    Limited information exists on the effects of sewage sludge on soil quality with regard to their ability to maintain soil functions. We studied effects of sewage sludge amendment on soil chemical properties, microbial community structure and microbial degradation of the herbicide glyphosate. Three months soil column leaching experiment has been conducted using alluvial soils (Eutric Fluvisol) with no prior history of sludge application. The soil was loamy with pH 7,4 and organic matter content of 3,5%. Soil material in the upper 2 cm of columns was mixed with dehydrated sewage sludge which was applied in amounts corresponding to the standards governing the use of sewage sludge for agricultural land. Sludge did increase some nutrients (total N, NH4+, available P and K, organic carbon) and some heavy metals contents (Zn, Cu, Pb) in soil. However, upper limits for heavy metals in agricultural soils were not exceeded. Results of heavy metal availability in soil determined by sequential extraction will be also presented. Restriction fragment length polymorphism (RFLP) analyses of 16s/18s rDNA, using universal fungal and bacterial primers, revealed clear shifts in bacterial and fungal community structure in the upper 2 cm of soils after amendment. Fungal fingerprints showed greater short term effects of sewage sludge, whereas sewage sludge seems to have prolonged effects on soil bacteria. Furthermore, sewage sludge amendment significantly increased glyphosate degradation from 21.6±1% to 33.6±1% over a 2 months period. The most probable reasons for shifts in microbial community structure and increased degradation of glyphosate are beneficial alterations to the physical-chemical characteristics of the soil. Negative effects of potentially toxic substances present in the sewage sludge on soil microbial community functioning were not observed with the methods used in our study.

  11. Uranium-series comminution ages of continental sediments: Case study of a Pleistocene alluvial fan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Victoria E.; DePaolo, Donald J.; Christensen, John N.

    2010-04-30

    Obtaining quantitative information about the timescales associated with sediment transport, storage, and deposition in continental settings is important but challenging. The uranium-series comminution age method potentially provides a universal approach for direct dating of Quaternary detrital sediments, and can also provide estimates of the sediment transport and storage timescales. (The word"comminution" means"to reduce to powder," reflecting the start of the comminution age clock as reduction of lithic parent material below a critical grain size threshold of ~;;50 mu m.) To test the comminution age method as a means to date continental sediments, we applied the method to drill-core samples of the glacially-derived Kings River Fan alluvial deposits in central California. Sediments from the 45 m core have independently-estimated depositional ages of up to ~;;800 ka, based on paleomagnetism and correlations to nearby dated sediments. We characterized sequentially-leached core samples (both bulk sediment and grain size separates) for U, Nd, and Sr isotopes, grain size, surface texture, and mineralogy. In accordance with the comminution age model, where 234U is partially lost from small sediment grains due to alpha recoil, we found that (234U/238U) activity ratios generally decrease with age, depth, and specific surface area, with depletions of up to 9percent relative to radioactive equilibrium. The resulting calculated comminution ages are reasonable, although they do not exactly match age estimates from previous studies and also depend on assumptions about 234U loss rates. The results indicate that the method may be a significant addition to the sparse set of available tools for dating detrital continental sediments, following further refinement. Improving the accuracy of the method requires more advanced models or measurements for both the recoil loss factor fa and weathering effects. We discuss several independent methods for obtaining fa on individual samples

  12. Spatial variability in bank resistance to erosion on a large meandering, mixed bedrock-alluvial river

    Science.gov (United States)

    Konsoer, Kory M.; Rhoads, Bruce L.; Langendoen, Eddy J.; Best, James L.; Ursic, Mick E.; Abad, Jorge D.; Garcia, Marcelo H.

    2016-01-01

    Spatial heterogeneity in the erosion-resistance properties of the channel banks and floodplains associated with sediment characteristics, vegetation, or bedrock can have a substantial influence on the morphodynamics of meandering rivers, resulting in highly variable rates of bank erosion and complex patterns of planform evolution. Although past studies have examined the spatial variability in bank erodibility within small rivers, this aspect of the erosion-resistance properties for large rivers remains poorly understood. Furthermore, with the exception of recent numerical modeling that incorporates stochastic variability of floodplain erosional resistance, most models of meandering river dynamics have assumed uniform erodibility of the bank and floodplain materials. The present paper investigates the lateral and vertical heterogeneity in bank material properties and riparian vegetation within two elongate meander loops on a large mixed bedrock-alluvial river using several geotechnical field and laboratory methods. Additionally, the bank stability and toe-erosion numerical model (BSTEM) and repeat terrestrial LiDAR surveys are used to evaluate the capacity of the bank material properties to modify the rates and mechanisms of bank retreat. Results show that the textural properties of the bank materials, soil cohesion, and critical shear stress necessary for sediment entrainment differ substantially between the two bends and are also highly variable within each bend - laterally and vertically. Trees growing along the banks increase the resistance to erosion by contributing to the shear strength of the bank materials and are capable of increasing bank stability along a large river. Locally outcropping bedrock also influences bank erodibility in both bends. The results of this study demonstrate that spatial variability in the erosion-resistance properties of the channel banks is an important factor contributing to spatial variability in the rates and mechanisms of bank

  13. Modeling analysis of ground water recharge potential on alluvial fans using limited data.

    Science.gov (United States)

    Munévar, A; Mariño, M A

    1999-01-01

    A modeling approach is developed to evaluate the potential for artificial recharge on alluvial fans in the Salinas Valley, California, using limited data of soil texture, soil hydraulic properties, and interwell stratigraphy. Promising areas for surface recharge are identified and mapped on a broad-scale using soil surveys, geologic investigations, permeability tests, and seasonal ground water response to rainfall and runoff. Two-dimensional representations of the vadose zone at selected sites are then constructed from drillers'logs and soil material types are estimated. Next, hydraulic properties are assigned to each soil material type by comparing them to laboratory-tested cores of similar soils taken from one site. Finally, water flow through the vadose zone is modeled in two dimensions at seven sites using a transient, finite-difference, variably saturated flow model. Average infiltration rates range from 0.84 to 1.54 cm/hr and recharge efficiency, the percentage of infiltrated water that reaches the water table, varies from 51% to 79%. Infiltration rates and recharge efficiency are found to be relatively insensitive to recharge basin ponding depth due to the thickness of the vadose zones modeled (31 to 84 m). The impact of artificial recharge on the Salinas Valley ground water basin is investigated by simulating the regional ground water response to surface spreading and streamflow augmentation with a recently calibrated, finite-element, ground water-surface water model for the basin. It was determined that a combined approach of surface recharge and streamflow augmentation significantly reduces the state of ground water overdraft and, to a lesser extent, reduces the rate of sea water intrusion.

  14. Using Lead Concentrations and Stable Lead Isotope Ratios to Identify Contamination Events in Alluvial Soils

    Directory of Open Access Journals (Sweden)

    Diane Saint-Laurent

    2010-01-01

    Full Text Available Soils contaminated with hydrocarbons (C10–C50, polycyclic aromatic hydrocarbons (PAHs, and other contaminants (e.g., As, Cd, Cu, Pb were recently discovered on the banks of the Saint-François and Massawippi rivers. Alluvial soils are contaminated over a distance of 100 kilometers, and the level of the contaminated-hydrocarbon layer in the soil profiles is among the highest at the Windsor and Richmond sites. Concentrations of lead and stable lead isotope ratios (204Pb/206Pb, 207Pb/206Pb, 208Pb/206Pb are also used to identify contamination events. The maximum and minimum values detected in soil profiles for arsenic, cadmium, and lead vary from 3.01 to 37.88 mg kg-1 (As, 0.11 to 0.81 mg kg-1 (Cd 12.32 to 149.13 mg kg-1 (Pb, respectively, while the 207Pb/206Pb isotopic ratio values are between 0.8545 and 0.8724 for all the profiles. The highest values of trace elements (As, Pb and Zn were detected in the hydrocarbon layer (C10–C50, most often located at the bottom of the profiles (160, 200, and 220 cm in depth. The various peaks recorded in the soils and the position of the profiles suggest that various contaminants were transported by the river on several occasions and infiltrated the soil matrix or deposited on floodplains during successive floods. Atmospheric particles which entered the river or deposited on riverbanks must also be considered as another source of pollution recorded in soils.

  15. EFFECT OF NPK FERTILIZER ON THE GROWTH OF SAPROPHYTIC FUNGI IN ALLUVIAL SOIL

    Directory of Open Access Journals (Sweden)

    Marijana PEŠAKOVIĆ

    2010-06-01

    Full Text Available The influence of different NPK fertilizer rates on the developement of the saprophytic fungi of the alluvial soil planted with plum culture has been studied over the three-year period (2003 – 2005. The trial was set up in the experimental plum orchard established by Fruit Research Institute Čačak (Serbia and at the laboratory of Department of Microbiology, Faculty of Agronomy Čačak (Serbia. The soil was treated with 8:16:24 + 3% of MgO mineral fertilizer in the following treatment variants: variant N1 – 400 kgha-1; variant N2 – 600 kgha-1; variant N3 – 800 kgha-1 and variant N4 –1000 kgha-1, all treatment variants being applied in three replications. Unfertilized soil served as the control. The size of the trial plot was 68 m2. The effect of the studied mineral fertilizer rates was determined three times over the growing season. It was checked by identification of the number of saprophytic fungi by the indirect rarefaction method on Czapek nutritive medium. The results of the study suggested that the number of the saprophytic fungi varied by different fertilizer rates, periods of sampling and years of study. The application of fertilizers brought about increase in the number of the saprophytic fungi. Of all studied treatment variants, the one with highest nitrogen rate (variant N4 exhibited the strongest effect. The influence of the applied fertilizer was highest over the third sampling period. Furthermore, the effect thereof was highest in 2003. The application of 600 kgha-1 of mineral fertilizer resulted in the highest plum yield.

  16. Probability distribution functions of turbulence in seepage-affected alluvial channel

    Science.gov (United States)

    Sharma, Anurag; Kumar, Bimlesh

    2017-02-01

    The present experimental study is carried out on the probability distribution functions (PDFs) of turbulent flow characteristics within near-bed-surface and away-from-bed surfaces for both no seepage and seepage flow. Laboratory experiments were conducted in the plane sand bed for no seepage (NS), 10% seepage (10%S) and 15% seepage (15%) cases. The experimental calculation of the PDFs of turbulent parameters such as Reynolds shear stress, velocity fluctuations, and bursting events is compared with theoretical expression obtained by Gram-Charlier (GC)-based exponential distribution. Experimental observations follow the computed PDF distributions for both no seepage and seepage cases. Jensen-Shannon divergence (JSD) method is used to measure the similarity between theoretical and experimental PDFs. The value of JSD for PDFs of velocity fluctuation lies between 0.0005 to 0.003 while the JSD value for PDFs of Reynolds shear stress varies between 0.001 to 0.006. Even with the application of seepage, the PDF distribution of bursting events, sweeps and ejections are well characterized by the exponential distribution of the GC series, except that a slight deflection of inward and outward interactions is observed which may be due to weaker events. The value of JSD for outward and inward interactions ranges from 0.0013 to 0.032, while the JSD value for sweep and ejection events varies between 0.0001 to 0.0025. The theoretical expression for the PDF of turbulent intensity is developed in the present study, which agrees well with the experimental observations and JSD lies between 0.007 and 0.015. The work presented is potentially applicable to the probability distribution of mobile-bed sediments in seepage-affected alluvial channels typically characterized by the various turbulent parameters. The purpose of PDF estimation from experimental data is that it provides a complete numerical description in the areas of turbulent flow either at a single or finite number of points.

  17. Breeding birds in managed forests on public conservation lands in the Mississippi Alluvial Valley

    Science.gov (United States)

    Twedt, Daniel J.; Wilson, R. Randy

    2017-01-01

    Managers of public conservation lands in the Mississippi Alluvial Valley have implemented forest management strategies to improve bottomland hardwood habitat for target wildlife species. Through implementation of various silvicultural practices, forest managers have sought to attain forest structural conditions (e.g., canopy cover, basal area, etc.) within values postulated to benefit wildlife. We evaluated data from point count surveys of breeding birds on 180 silviculturally treated stands (1049 counts) that ranged from 1 to 20 years post-treatment and 134 control stands (676 counts) that had not been harvested for >20 years. Birds detected during 10-min counts were recorded within four distance classes and three time intervals. Avian diversity was greater on treated stands than on unharvested stands. Of 42 commonly detected species, six species including Prothonotary Warbler (Prothonotaria citrea) and Acadian Flycatcher (Empidonax virescens) were indicative of control stands. Similarly, six species including Indigo Bunting (Passerina cyanea) and Yellow-breasted Chat (Icteria virens) were indicative of treated stands. Using a removal model to assess probability of detection, we evaluated occupancy of bottomland forests at two spatial scales (stands and points within occupied stands). Wildlife-forestry treatment improved predictive models of species occupancy for 18 species. We found years post treatment (range = 1–20), total basal area, and overstory canopy were important species-specific predictors of occupancy, whereas variability in basal area was not. In addition, we used a removal model to estimate species-specific probability of availability for detection, and a distance model to estimate effective detection radius. We used these two estimated parameters to derive species densities and 95% confidence intervals for treated and unharvested stands. Avian densities differed between treated and control stands for 16 species, but only Common Yellowthroat

  18. Orbital forcing in the early Miocene alluvial sediments of the western Ebro Basin, Northeast Spain

    Science.gov (United States)

    Garces, M.; Larrasoaña, J. C.; Muñoz, A.; Margalef, O.; Murelaga, X.

    2009-04-01

    Paleoclimatic reconstructions from terrestrial records are crucial to assess the regional variability of past climates. Despite the apparent direct connection between continental sedimentary environments and climate, interpreting the climatic signature in ancient non-marine sedimentary sequences is often overprinted by source-area related signals. In this regard, foreland basins appear as non-ideal targets as tectonically-driven subsidence and uplift play a major control on the distribution and evolution of sedimentary environments and facies. Foreland basins, however, often yield among the thickest and most continuous stratigraphic records available on continents. The Ebro Basin (north-eastern Spain) is of particular interest among the circum-mediterranean alpine foreland basins because it evolved into a land-locked closed basin since the late Eocene, leading to the accumulation of an exceptionally thick (>5500 m) and continuous sequence of alluvial-lacustrine sediments over a period of about 25 Myr. In this paper we present a detailed cyclostratigraphic study of a 115 m thick section in the Bardenas Reales de Navarra region (western Ebro Basin) in order to test orbital forcing in the Milankovitch frequency band. The study section corresponds to the distal alluvial-playa mud flats which developed in the central sector of the western Ebro Basin, with sediments sourced from both the Pyrenean and Iberian Ranges. Sediments consist of brown-red alluvial clay packages containing minor fine-grained laminated sandstones sheet-beds and channels, grey marls and thin bedded lacustrine limestones arranged in 10 to 20 m thick fining-upwards sequences. Red clayed intervals contain abundant nodular gypsum interpreted as representing a phase of arid and low lake level conditions, while grey marls and limestones indicate wetter intervals recording the expansion of the inner shallow lakes. A magnetostratigraphy-based chronology indicates that the Peñarroya section represents a

  19. Strath terraces on the western High Plains indicate climatically-driven variations in sediment supply from source basins in the Colorado Front Range

    Science.gov (United States)

    Foster, M. A.; Dühnforth, M.; Anderson, R. S.

    2013-12-01

    Large strath terraces adjacent to the Colorado Front Range record the local history of fluvial planation and incision into the erodible rocks of the Denver basin over the last 2 million years. Terrace surfaces have been correlated into ~6 alluvial units using elevation and soil development; each alluvial unit was thought to represent a fairly consistent elevation of the Denver basin during various stages of exhumation, driven by base-level fall of the South Platte River. Here we show instead that (1) strath terraces in the western High Plains cannot be correlated based on elevation alone and (2) exhumation of the Denver basin is likely spatially and temporally variable due to climatically-driven variations in sediment supply from the source basins. We collected samples for cosmogenic radionuclide (CRN) profiles (10Be and 26Al) and a soil chronosequence from three strath terraces adjacent to Lefthand Creek near Boulder, CO. 10Be profile data on the upper- and middle-elevation terraces yield dates of 95 ka and 91 ka; these dates are much younger than the correlative alluvial units to the south of Boulder, which date to 1.5 Ma and 250 ka, respectively. Soils on the upper and middle terraces are similar in soil development and clast weathering, consistent with the narrow time window obtained from CRN dating of the two units. 10Be-derived rates for catchment-wide paleo-denudation are ~8.0 cm/ka from the flat and broad upper-terrace gravels and ~3.5 cm/ka from the steeper and narrower middle-terrace gravels. Young terraces at Lefthand Canyon are more consistent with a model of fluvial incision and aggradation driven by climate-controlled variations in sediment production from source basins in the Front Range. High catchment-wide denudation rates generate a high sediment supply, leading to aggradation and lateral planation. Terrace sediments are likely deposited and eroded multiple times during periods of lateral planation; the most recent occupation is preserved in the

  20. Chinese tallow: Invading the southeastern Coastal Plain

    Science.gov (United States)

    ,

    2000-01-01

    Chinese tallow is an ornamental tree with colorful autumn foliage that can survive full sunlight and shade, flooding, drought, and in some cases fire. To horticulturists this kind of tree sounds like a dream, but to ecologists, land managers, and land owners this kind of tree can be a nightmare, especially when it invades an area and takes over native vegetation. Chinese tallow (Triadica sebifera), a nonnative tree from China, is currently transforming the southeastern Coastal Plain.Over the last 30 years, Chinese tallow has become a common tree in old fields and bottomland swamps of coastal Louisiana. Several studies at the U.S. Geological Survey’s National Wetlands Research Center (NWRC), Lafayette, Louisiana, are aimed at understanding the factors that contribute to Chinese tallow growth, spread, and management.When tallow invades, it eventually monopolizes an area, creating a forest without native animal or plant species. This tree exhibits classic traits of most nonnative invaders: it is attractive so people want to distribute it, it has incredible resiliency, it grows quickly and in a variety of soils, and it is resistant to pests.In the coastal prairie of Louisiana and Texas, Chinese tallow can grow up to 30 feet and shade out native sun-loving prairie species. The disappearing of prairie species is troublesome because less than 1% of original coastal prairie remains, and in Louisiana, less than 500 of the original 2.2 million acres still exist.Tallow reproduces and grows quickly and can cause large-scale ecosystem modification (fig. 1). For example, when it completely replaces native vegetation, it has a negative effect on birds by degrading the habitat. Besides shading out grasses that cattle like to eat, it can also be potentially harmful to humans and animals because of its berries (fig. 2) and plant sap that contain toxins. There is some concern its leaves may shed toxins that change the soil chemistry and make it difficult for other plants to grow.

  1. Flood hydrology and methylmercury availability in Coastal Plain rivers

    Science.gov (United States)

    Bradley, Paul M.; Journey, Celeste A.; Chapelle, Francis H.; Lowery, Mark A.; Conrads, Paul A.

    2010-01-01

    Mercury (Hg) burdens in top-predator fish differ substantially between adjacent South Carolina Coastal Plain river basins with similar wetlands coverage. In the Congaree River, floodwaters frequently originate in the Blue Ridge and Piedmont regions, where wetlands coverage and surface water dissolved methylmercury (MeHg) concentrations are low. Piedmont-driven flood events can lead to downward hydraulic gradients in the Coastal Plain riparian wetland margins, inhibiting MeHg transport from wetland sediments, and decreasing MeHg availability in the Congaree River habitat. In the adjacent Edisto River basin, floodwaters originate only within Coastal Plain sediments, maintaining upward hydraulic gradients even during flood events, promoting MeHg transport to the water column, and enhancing MeHg availability in the Edisto River habitat. These results indicate that flood hydrodynamics contribute to the variability in Hg vulnerability between Coastal Plain rivers and that comprehensive regional assessment of the relationship between flood hydrodynamics and Hg risk in Coastal Plain streams is warranted.

  2. Plains Elevated Convection at Night (PECAN) Experiment Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Turner, D [National Oceanic and Atmospheric Administration; Parsons, D [NCAR; Geerts, B [Department of Atmospheric Science, University of Wyoming

    2015-03-01

    The Plains Elevated Convection at Night (PECAN) experiment is a large field campaign that is being supported by the National Science Foundation (NSF) with contributions from the National Oceanic and Atmospheric Administration (NOAA), the National Atmospheric and Space Administration (NASA), and the U.S. Department of Energy (DOE). The overarching goal of the PECAN experiment is to improve the understanding and simulation of the processes that initiate and maintain convection and convective precipitation at night over the central portion of the Great Plains region of the United States (Parsons et al. 2013). These goals are important because (1) a large fraction of the yearly precipitation in the Great Plains comes from nocturnal convection, (2) nocturnal convection in the Great Plains is most often decoupled from the ground and, thus, is forced by other phenomena aloft (e.g., propagating bores, frontal boundaries, low-level jets [LLJ], etc.), (3) there is a relative lack of understanding how these disturbances initiate and maintain nocturnal convection, and (4) this lack of understanding greatly hampers the ability of numerical weather and climate models to simulate nocturnal convection well. This leads to significant uncertainties in predicting the onset, location, frequency, and intensity of convective cloud systems and associated weather hazards over the Great Plains.

  3. Quaternary evolution of the Southern Apennines coastal plains: a review

    Science.gov (United States)

    Santangelo, Nicoletta; Romano, Paola; Ascione, Alessandra; Russo Ermolli, Elda

    2017-02-01

    The Quaternary evolution of the main coastal basins located along the southwestern margin of the Southern Apennines has been reconstructed by integrating the huge amount of existing stratigraphical and geomorphological data. The information produced in the last twenty years has shed new light on the recent (late Middle Pleistocene to Present) history of the Campanian and Sele plains or basins. During the early Quaternary, the analysed coastal basins originated as half-grabens in response to opening processes active since the late Tortonian in the southern Tyrrhenian back-arc basin. In some of these basins (e.g. the Campanian Plain), volcanism has also played an important role. In the inner sectors of the coastal basins, the complex interplay between block faulting, sedimentary inputs and glacioeustatic fluctuations gave rise to relative sea-level change and related coastline migrations, leading to the formation of the present-day coastal plains. In the Sele Plain basin, the construction of the present-day landscape mainly resulted from the substantial ceasing of subsidence in the final part of the Middle Pleistocene. Conversely, a strong contribution to the recent evolution of the Campanian Plain has been provided by abundant volcaniclastic aggradation, able to hinder the effect of the vertical motions that occurred in the last 100 ka.

  4. Quaternary evolution of the Southern Apennines coastal plains: a review

    Directory of Open Access Journals (Sweden)

    Santangelo Nicoletta

    2017-02-01

    Full Text Available The Quaternary evolution of the main coastal basins located along the southwestern margin of the Southern Apennines has been reconstructed by integrating the huge amount of existing stratigraphical and geomorphological data. The information produced in the last twenty years has shed new light on the recent (late Middle Pleistocene to Present history of the Campanian and Sele plains or basins. During the early Quaternary, the analysed coastal basins originated as half-grabens in response to opening processes active since the late Tortonian in the southern Tyrrhenian back-arc basin. In some of these basins (e.g. the Campanian Plain, volcanism has also played an important role. In the inner sectors of the coastal basins, the complex interplay between block faulting, sedimentary inputs and glacioeustatic fluctuations gave rise to relative sea-level change and related coastline migrations, leading to the formation of the present-day coastal plains. In the Sele Plain basin, the construction of the present-day landscape mainly resulted from the substantial ceasing of subsidence in the final part of the Middle Pleistocene. Conversely, a strong contribution to the recent evolution of the Campanian Plain has been provided by abundant volcaniclastic aggradation, able to hinder the effect of the vertical motions that occurred in the last 100 ka.

  5. Flood hydrology and methylmercury availability in coastal plain rivers.

    Science.gov (United States)

    Bradley, Paul M; Journey, Celeste A; Chapelle, Francis H; Lowery, Mark A; Conrads, Paul A

    2010-12-15

    Mercury (Hg) burdens in top-predator fish differ substantially between adjacent South Carolina Coastal Plain river basins with similar wetlands coverage. In the Congaree River, floodwaters frequently originate in the Blue Ridge and Piedmont regions, where wetlands coverage and surface water dissolved methylmercury (MeHg) concentrations are low. Piedmont-driven flood events can lead to downward hydraulic gradients in the Coastal Plain riparian wetland margins, inhibiting MeHg transport from wetland sediments, and decreasing MeHg availability in the Congaree River habitat. In the adjacent Edisto River basin, floodwaters originate only within Coastal Plain sediments, maintaining upward hydraulic gradients even during flood events, promoting MeHg transport to the water column, and enhancing MeHg availability in the Edisto River habitat. These results indicate that flood hydrodynamics contribute to the variability in Hg vulnerability between Coastal Plain rivers and that comprehensive regional assessment of the relationship between flood hydrodynamics and Hg risk in Coastal Plain streams is warranted.

  6. Water availability and use pilot; methods development for a regional assessment of groundwater availability, southwest alluvial basins, Arizona

    Science.gov (United States)

    Tillman, Fred D; Cordova, Jeffrey T.; Leake, Stanley A.; Thomas, Blakemore E.; Callegary, James B.

    2011-01-01

    Executive Summary: Arizona is located in an arid to semiarid region in the southwestern United States and is one of the fastest growing States in the country. Population in Arizona surpassed 6.5 million people in 2008, an increase of 140 percent since 1980, when the last regional U.S. Geological Survey (USGS) groundwater study was done as part of the Regional Aquifer System Analysis (RASA) program. The alluvial basins of Arizona are part of the Basin and Range Physiographic Province and cover more than 73,000 mi2, 65 percent of the State's total land area. More than 85 percent of the State's population resides within this area, accounting for more than 95 percent of the State's groundwater use. Groundwater supplies in the area are expected to undergo further stress as an increasing population vies with the State's important agricultural sector for access to these limited resources. To provide updated information to stakeholders addressing issues surrounding limited groundwater supplies and projected increases in groundwater use, the USGS Groundwater Resources Program instituted the Southwest Alluvial Basins Groundwater Availability and Use Pilot Program to evaluate the availability of groundwater resources in the alluvial basins of Arizona. The principal products of this evaluation of groundwater resources are updated groundwater budget information for the study area and a proof-of-concept groundwater-flow model incorporating several interconnected groundwater basins. This effort builds on previous research on the assessment and mapping of groundwater conditions in the alluvial basins of Arizona, also supported by the USGS Groundwater Resources Program. Regional Groundwater Budget: The Southwest Alluvial Basins-Regional Aquifer System Analysis (SWAB-RASA) study produced semiquantitative groundwater budgets for each of the alluvial basins in the SWAB-RASA study area. The pilot program documented in this report developed new quantitative estimates of groundwater

  7. Simulating Groundwater Recharge Across the Southern High Plains

    Science.gov (United States)

    Smidt, S. J.; Haacker, E. M.; Kendall, A. D.; Hyndman, D. W.

    2015-12-01

    Quantifying recharge and water availability across the Southern High Plains is a difficult, but necessary, challenge for future groundwater and agricultural projections. Overland flow is not common due to limited precipitation, dry soils, and high evapotranspiration. The majority of runoff is temporarily stored in playa lakes, leading to the bulk of recharge across the region occurring in localized infiltration zones beneath these lakes. Despite the importance of regional recharge estimates, limited information exists that integrates complex characteristics of the land, climate, and hydrology in order to quantify recharge across the entire Southern High Plains aquifer. This study applies the Landscape Hydrology Model (LHM) to capture these characteristics and simulate surface water flow and groundwater recharge. This model simulates the complete water cycle across large regions, including irrigation estimates, establishing a framework to estimate recharge and groundwater availability in the Southern High Plains region. Results from this study can be used to predict the likely impacts of climate change and improve water management strategies.

  8. Tobacco branding, plain packaging, pictorial warnings, and symbolic consumption.

    Science.gov (United States)

    Hoek, Janet; Gendall, Philip; Gifford, Heather; Pirikahu, Gill; McCool, Judith; Pene, Gina; Edwards, Richard; Thomson, George

    2012-05-01

    We use brand association and symbolic consumption theory to explore how plain cigarette packaging would influence the identities young adults cocreate with tobacco products. Group discussions and in-depth interviews with 86 young adult smokers and nonsmokers investigated how participants perceive tobacco branding and plain cigarette packaging with larger health warnings. We examined the transcript data using thematic analysis and explored how removing tobacco branding and replacing this with larger warnings would affect the symbolic status of tobacco brands and their social connotations. Smokers used tobacco brand imagery to define their social attributes and standing, and their connection with specific groups. Plain cigarette packaging usurped this process by undermining aspirational connotations and exposing tobacco products as toxic. Replacing tobacco branding with larger health warnings diminishes the cachet brand insignia creates, weakens the social benefits brands confer on users, and represents a potentially powerful policy measure.

  9. Risks associated with rainfall and floods in the Moldavian Plain

    Directory of Open Access Journals (Sweden)

    Dan BURUIANĂ

    2015-03-01

    Full Text Available Climate changes, less effective land exploitation and insufficient security infrastructure against extreme phenomena induce vulnerabilities for the Moldavian Plain, where floods are relatively frequent. The middle and lower segments of the major streams dispose of improved hydro-technical infrastructure to prevent floods, still, the secondary streams and tributaries, with pronounced torrential characterremain vulnerable. The torrential character of the majority of rivers inthe Moldavian Plain results in management difficulties related with risksat maximum flow, especially on the first rank tributaries. Our studyanalyzes the main causes and consequences of floods in the MoldavianPlain and identifies potentially significant flood risks areas.

  10. Miocene alluvial fan-alkaline playa lignite-trona bearing deposits from an inverted basin in Anatolia: sedimentology and tectonic controls on deposition

    Science.gov (United States)

    İnci, Uǧur

    1991-04-01

    During the Middle through Late Miocene, over 1200 m of clastics, carbonates and evaporites accumulated in the depositional basin situated in northwestern Ankara province of Central Anatolia. Detailed stratigraphic and sedimentological analyses of the exposed sequence exhibits three major facies: (1) lower alluvial, (2) upper alluvial, and (3) lacustrine. The lower alluvial facies consists primarily of volcaniclastic debris-flow, boulder and channel conglomerate, sandstone, siltstone, mudstone and two lignite horizons. These rock assemblages were deposited in alluvial fans and a braided-river system. The lower and upper lignite seams were laid down in swamps and lake-margin mud-flat environments associated with this river system. The upper alluvial facies is characterized by red conglomerate, fine-grained and cross-bedded sandstone, mudstone and calcareous mudstone units. The dominant depositional environments are interpreted to be alluvial fan, braided-river, and mud-flat. The base of the lacustrine deposits interfingers with the lower alluvial facies and consists of dolomitic claystone, bituminous shale, trona and intraformational conglomerate lithofacies. The sedimentary features of the dolomitic claystone and trona lithofacies suggest deposition in a playa-lake type environment. The bituminous shale is a transgressive deposit laid down in a shallow, but expanded lake environment. Sedimentological and structural characteristics of the intraformational conglomerate lithofacies indicate synsedimentary tectonism, intrabasinal erosion, redeposition and sediment selection toward the deposition centre of the lake environment. The green claystone lithofacies has three units: (a) the claystone-bedded chert-analcitized tuff alternation and siliceous carbonate lithofacies of the lacustrine system, deposited in a perennial lake environment; (b) montmorillonitic olive-green claystone containing mud-cracks, ripple mark and desiccation cracks filled by gypsum, deposited in a

  11. Geomorphic characterization of the Fortymile Wash alluvial fan, Nye County, Nevada, in support of the Yucca Mountain Project

    Science.gov (United States)

    Cline, M.; Delong, S.; Pelletier, J.

    2005-12-01

    In the event of an unlikely volcanic eruption through the proposed high-level radioactive waste repository at Yucca Mountain, contaminated ash may be deposited in portions of the Fortymile Wash drainage basin and subsequently redistributed to the Fortymile Wash alluvial fan by fluvial processes. Characterization of the Fortymile Wash alluvial fan has been undertaken as part of an effort to quantify the transport of contaminated ash throughout the fluvial system, especially to define the spatial distribution of fluvial activity over time scales of repository operation, and the rates of radionuclide migration into different soils on the fan. The Fortymile Wash alluvial fan consists of extremely low relief terraces as old as 70 ka. By conducting soils-geomorphic mapping and correlating relative surface ages with available geochronology from the Fortymile Wash fan and adjacent piedmonts, we identified 4 distinct surfaces on the fan. Surface ages are used to predict the relative stability of different areas of the fan to fluvial activity. Pleistocene-aged surfaces are assumed to be fluvially inactive over the 10 kyr time scale, for example. Our mapping and correlation provides a map of the depozone for contaminated ash that takes into account long-term channel migration for the time scales of repository operation, and it provides a geomorphic framework for predicting radionuclide dispersion rates into different soils across the fan. The standard model for vertical migration of radionuclides in soil is diffusion; therefore we used diffusion profiles derived from 137Cs fallout to determine radionuclide infiltration rates on the various geomorphic surfaces. The results show a strong inverse correlation of the geomorphic surface age and diffusivity values inferred from the 137Cs profiles collected on the different surfaces of the fan.

  12. Near-decadal changes in nitrate and pesticide concentrations in the South Platte River alluvial aquifer, 1993-2004

    Science.gov (United States)

    Paschke, S.S.; Schaffrath, K.R.; Mashbum, S.L.

    2008-01-01

    The lower South Platte River basin of Colorado and Nebraska is an area of intense agriculture supported by surface-water diversions from the river and ground-water pumping from a valley-fill alluvial aquifer. Two well networks consisting of 45 wells installed in the South Platte alluvial aquifer were sampled in the early 1990s and again in the early 2000s to examine near-decadal ground-water quality changes in irrigated agricultural areas. Ground-water age generally increases and dissolved-oxygen content decreases with distance along flow paths and with depdi below the water table, and denitrification is an important natural mitigation mechanism for nitrate in downgradient areas. Ground-water travel time from upland areas to the river ranges from 12 to 31 yr on the basis of apparent ground-water ages. Ground-water nitrate concentrations for agricultural land-use wells increased significantly for oxidized samples over the decade, and nitrogen isotope ratios for oxidized samples indicate synthetic fertilizer as the predominant nitrate source. Ground-water concentrations of atrazine, DEA, and prometon decreased significandy. The decrease in pesticide concentrations and a significant increase in the ratio of DEA to atrazine suggest decreases in pesticide concentrations are likely caused by local decreases in application rates and/or degradation processes and that atrazine degradation is promoted by oxidizing conditions. The difference between results for oxidizing and nitrate-reducing conditions indicates redox state is an important variable to consider when evaluating ground-water quality trends for redox-sensitive constituents such as nitrate and pesticides in the South Platte alluvial aquifer. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  13. Tracing recent environmental changes and pedogenesis using geochemistry and micromorphology of alluvial soils, Sabie-Sand River Basin, South Africa

    Science.gov (United States)

    Eze, Peter N.; Knight, Jasper; Evans, Mary

    2016-09-01

    Three pedons on the alluvial terraces of the Sabie-Sand River Basin within Kruger National Park, South Africa, were studied to improve our understanding of recent environmental changes, and assess degree of chemical weathering and pedogenesis in the area using geochemical and micromorphology proxies. Particle-size distributions were obtained using Malvern Mastersizer; soil geochemistry was determined by XRF and thin sections by routine laboratory procedures. The soils are predominantly sandy (> 94% sand in all samples). The mean phi-values of the soils had little variation suggesting that reworking of sediments upwards in individual profiles produced a more uniform pedogenesis rather than coming from different physical sources. Calcification is the dominant pedogenic process in these alluvial soils. The Chemical Index of Alteration (CIA) proved a more suitable index than Chemical Index of Weathering (CIW) for evaluating weathering in the terraces. The micromass and b-fabrics are mostly granostriated and partly brown mosaic speckled. MISECA values for the degree of soil development range from 4 to 9, which mean weakly to moderately-developed soils. Coarse secondary calcite nodules and coatings are responsible for cementation as observed in pedon 2, which suggests calcium carbonate precipitation from periodical flooding and evaporating groundwater events. The features and diagnostic properties of the soils on the alluvial terraces along the Sabie-Sand River provide evidence for land surface impacts of recent environmental changes in this internationally important conservation area. Precise dating of calcium carbonate precipitates is, however, needed to put the observed evidence into a wider geochronological perspective.

  14. Flood susceptibility assessment in a highly urbanized alluvial fan: the case study of Sala Consilina (southern Italy

    Directory of Open Access Journals (Sweden)

    N. Santangelo

    2011-10-01

    Full Text Available This paper deals with the risk assessment to alluvial fan flooding at the piedmont zone of carbonate massifs of the southern Apennines chain (southern Italy. These areas are prime spots for urban development and are generally considered to be safer than the valley floors. As a result, villages and towns have been built on alluvial fans which, during intense storms, may be affected by flooding and/or debris flow processes.

    The study area is located at the foothills of the Maddalena mountains, an elongated NW-SE trending ridge which bounds to the east the wide intermontane basin of Vallo di Diano. The area comprises a wide detrital talus (bajada made up by coalescent alluvial fans, ranging in age from the Middle Pleistocene to the Holocene. Historical analysis was carried out to ascertain the state of activity of the fans and to identify and map the zones most hit by past flooding. According to the information gathered, the Sala Consilina fans would appear prone to debris flows; in the past these processes have produced extensive damage and loss of life in the urban area. The watershed basins feeding the fans have very low response times and may produce debris flow events with high magnitudes. Taking into account the historical damage, the fan surface morphology, and the present urban development (street orientation and hydraulic network, the piedmont area was zoned and various susceptibility classes were detected. These results may represent a useful tool for studies aiming at territorial hazard mapping and civil protection interventions.

  15. Spatial variability of organochlorine pesticides (DDTs and HCHs) in surface soils from the alluvial region of Beijing, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-yan; GAO Ru-tai; HUANG Yuan-fang; JIA Xiao-hong; JIANG Shu-ren

    2007-01-01

    The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including α-, β-, γ-, and δ-isomers) and total DDTs (i ncluding p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT) in the surface soils tested were in the range from nondetectable to 31.72 μg/kg dry soil, with a mean value of 0.91, and from nondetectable to 5910.83 μg/kg dry soil, with a mean value of 32.13,respectively. It was observed that concentrations of HCHs in all soil samples and concentrations of DDTs in 112 soil samples were much lower than the first grade (50 μg/kg) permitted in "Environment quality standard for soils in China (GB15618-1995)". This suggests that the pollution due to organochlorine pesticides was generally not significant in the farmland soils in the Beijing alluvial region. In this study, the spatial distribution and trend of HCHs and DDTs were analyzed using Geostatistical Analyst and GS+(513).Spatial distribution indicated how these pesticides had been applied in the past. Trend analysis showed that the concentrations of HCHs,DDTs, and their related metabolites followed an obvious distribution trend in the surface soils from the alluvial region of Beijing.

  16. Causes and Predictability of the 2012 Great Plains Drought

    Science.gov (United States)

    Hoerling, M.; Eischeid, J.; Kumar, A.; Leung, R.; Mariotti, A.; Mo, K.; Schubert, S.; Seager, R.

    2013-01-01

    Central Great Plains precipitation deficits during May-August 2012 were the most severe since at least 1895, eclipsing the Dust Bowl summers of 1934 and 1936. Drought developed suddenly in May, following near-normal precipitation during winter and early spring. Its proximate causes were a reduction in atmospheric moisture transport into the Great Plains from the Gulf of Mexico. Processes that generally provide air mass lift and condensation were mostly absent, including a lack of frontal cyclones in late spring followed by suppressed deep convection in summer owing to large-scale subsidence and atmospheric stabilization. Seasonal forecasts did not predict the summer 2012 central Great Plains drought development, which therefore arrived without early warning. Climate simulations and empirical analysis suggest that ocean surface temperatures together with changes in greenhouse gases did not induce a substantial reduction in summertime precipitation over the central Great Plains during 2012. Yet, diagnosis of the retrospective climate simulations also reveals a regime shift toward warmer and drier summertime Great Plains conditions during the recent decade, most probably due to natural decadal variability. As a consequence, the probability for severe summer Great Plains drought may have increased in the last decade compared to the 1980s and 1990s, and the so-called tail-risk for severe drought may have been heightened in summer 2012. Such an extreme drought event was nonetheless still found to be a rare occurrence within the spread of 2012 climate model simulations. Implications of this study's findings for U.S. seasonal drought forecasting are discussed.

  17. Delineation of alluvial fans from Digital Elevation Models with a GIS algorithm for the geomorphological mapping of the Earth and Mars

    Science.gov (United States)

    Norini, Gianluca; Zuluaga, Maria Clara; Ortiz, Iris Jill; Aquino, Dakila T.; Lagmay, Alfredo Mahar F.

    2016-11-01

    Alluvial fans are prominent depositional geomorphic features present in nearly all global climates on Earth, and also found on Mars. In this study, we present a Geographic Information System (GIS) algorithm designed for the semi-automated detection of alluvial fans that are connected to their contributing upstream drainage network, from the analysis of Digital Elevation Models (DEMs). Through a combination of spatial analysis procedures, the GIS algorithm generates maps of alluvial fans and their upstream source drainage and watersheds. Tests of the algorithm in areas with well-known alluvial fans indicate that this new GIS procedure is capable of high-accuracy mapping of the fan apexes and correct delineation of fan deposits, in both arid and humid climates. Possible future applications of the GIS algorithm presented in this study include the systematic survey of alluvial fans at the local, regional and planetary scales, important for geologic hazard assessment, studies on the evolution of climate, analysis of continental sedimentary environments, understanding of the interplay between the endogenous dynamics and exogenous processes, and the evaluation of natural resources.

  18. Tributary debris fans and the late Holocene alluvial chronology of the Colorado River, eastern Grand Canyon, Arizona

    Science.gov (United States)

    Hereford, R.; Thompson, K.S.; Burke, K.J.; Fairley, H.C.

    1996-01-01

    Bouldery debris fans and sandy alluvial terraces of the Colorado River developed contemporaneously during the late Holocene at the mouths of nine major tributaries in eastern Grand Canyon. The age of the debris fans and alluvial terraces contributes to understanding river hydraulics and to the history of human activity along the river, which has been concentrated on these surfaces for at least two to three millennia. Poorly sorted, coarse-grained debris-flow deposits of several ages are interbedded with, overlie, or are overlapped by three terrace-forming alluviums. The alluvial deposits are of three age groups: the striped alluvium, deposited from before 770 B.C. to about A.D. 300; the alluvium of Pueblo II age deposited from about A.D. 700 to 1200; and the alluvium of the upper mesquite terrace, deposited from about A.D. 1400 to 1880. Two elements define the geomorphology of a typical debris fan: the large, inactive surface of the fan and a smaller, entrenched, active debris-flow channel and fan that is about one-sixth the area of the inactive fan. The inactive fan is segmented into at least three surfaces with distinctive weathering characteristics. These surfaces are conformable with underlying debris-flow deposits that date from before 770 B.C. to around A.D. 660, A.D. 660 to before A.D. 1200, and from A.D. 1200 to slightly before 1890, respectively, based on late-19th-century photographs, radiocarbon and archaeologic dating of the three stratigraphically related alluviums, and radiocarbon dating of fine-grained debris-flow deposits. These debris flows aggraded the fans in at least three stages beginning about 2.8 ka, if not earlier in the late Holocene. Several main-stem floods eroded the margin of the segmented fans, reducing fan symmetry. The entrenched, active debris-flow channels contain deposits debris fans at the mouth of the channel adjacent to the river. Early and middle Holocene debris-flow and alluvial deposits have not been recognized, as they were

  19. Using Synthetic Aperture Radar data of terrestrial analogs to test for alluvial fan formation mechanisms on Titan

    Science.gov (United States)

    Cartwright, R. J.; Burr, D. M.

    2017-03-01

    Landforms on Titan include features hypothesized to be alluvial fans. Terrestrial alluvial fans form via two processes: fluid-gravity flows (sheetfloods) and sediment-gravity flows (debris flows). Along the Panamint Mountain Range in Death Valley, California, USA, seven fans formed primarily by debris flows are located adjacent to seven fans formed primarily by sheetfloods. The causal difference between these two groupings stems from their catchment lithologies; the debris flow fan catchments are clay-rich and relatively sand-poor, and the sheetflood fan catchments are clay-poor and sand-rich. On Titan, the low and mid latitudes are dominated by sand seas, demonstrating that sand is available for transport. At high latitudes, these sand seas are absent, suggesting that transportable sand is scarce. Based on the sedimentology of the two Panamint Range fan types, we hypothesize that possible fans at lower latitudes on Titan are formed by sheetfloods, whereas those at higher latitudes formed primarily by debris flows. To test these hypotheses, we measured and analyzed the mean normalized radar cross sections (σ°) and changes in σ° with downfan distance for debris flow and sheetflood fans along the Panamint Range. We then compared the results with the same measurements for possible fans on Titan. We find that, in the Panamint Range, debris flow fans are brighter than sheetflood fans and have greater change in σ° with downfan distance, and that on Titan, low-latitude possible fans are likewise brighter than the fans at high latitudes with greater change in σ° with downfan distance. Consequently, our findings suggest that low-latitude possible fans on Titan are formed primarily by debris flows, whereas high-latitude possible fans on Titan are formed primarily by sheetfloods. Thus, our results do not support our hypotheses. Scenarios to explain these results include: (1) high-latitude possible fans are dominated by radar-dark debris flow deposits, (2) low- and mid

  20. The significance of avulsion phenomena in the alluvial filling configuration of a mountain stream: Venero Claro (Central Spain)

    Science.gov (United States)

    Ruiz-Villanueva, V.; Díez-Herrero, A.; Bodoque, J. M.; Fernández-García, P.; Ballesteros, J. A.

    2009-04-01

    In the dynamics and evolution of large river floodplains, alluvial fans and debris cones, avulsion phenomena have been considered very important. However, traditionally, in mountain streams, avulsion phenomena have been underestimated because they are not very frequent, and usually they are restricted to little chute cut-off. Nevertheless, there are mountainous areas where the valley bottom gets wider, and the alluvial filling works like an elongated debris cone. The Cabrera Stream in the Venero Claro reach (Spanish Central System) is one of these special areas. In this case, avulsion phenomena took place triggered by flash floods, and they were usually associated with hyperconcentrated flows, which exceeded the upper level of levees and banks, redefining the sedimentary architecture of the alluvial filling. In this study, an analysis of geomorphologic and sedymentological evolution of the alluvial filling in Venero Claro have been carried out. On this way, cartography made from the 19th Century until ninety ages were compared, and a stereoscopic analysis of aerial photographs and digital ortoimages were applied. Furthermore, the sedimentary filling was studied applying classic sedimentological techniques, such as a description and interpretation of sedimentary structures and facies analysis at field. As a result of the geomorphologic evolution analysis, a straightforward evolution model is proposed. This model enhances the relevant importance of the avulsion phenomena in the geomorphologic configuration of the Cabrera Stream in the Venero Claro reach. From the river pattern point of view, the avulsion phenomena originate capture processes in the main stream and its tributaries. As a result of these processes, the drainage network pattern changes successively from dendritic to sub-parallel. On other hand, from the sedimentologic point of view, the stratigraphy is composed of channel facies (debris flow facies and fluvial-torrential gravelbars) and back

  1. Plain and Rolled Images from Paired Fingerprint Cards

    Science.gov (United States)

    NIST Plain and Rolled Images from Paired Fingerprint Cards (PC database for purchase)   NIST Special Database 29 is being distributed for use in development and testing fingerprint matching systems. The data consist of 216 ten-print fingerprint card pairs with both the rolled and plains (from a bottom of the fingerprint card) scanned at 19.7 pixels per mm. A newer version of the compression/decompression software on the CDROM can be found at the website http://www.nist.gov/itl/iad/ig/nigos.cfm as part of the NBIS package.

  2. Residual Tensile Strength of Plain Concrete Under Tensile Fatigue Loading

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The functional relation between the residual tensile strength of plain concrete and number of cycles was determined. 99 tappered prism specimens of plain concrete were tested under uniaxial tensile fatigue loading. Based on the probability distribution of the residual tensile strength, the empirical expressions of the residual tensile strength corresponding to the number of cycles were obtained. The residual tensile strength attenuating curves can be used to predict the residual fatigue life of the specimen under variable-amplitude fatigue loading. There is a good correlation between residual tensile strength and residual secant elastic modulus.The relationship between the residual secant elastic modulus and number of cycles was also established.

  3. S2-Project: Near-fault earthquake ground motion simulation in the Sulmona alluvial basin

    Science.gov (United States)

    Faccioli, E.; Stupazzini, M.; Galadini, F.; Gori, S.

    2008-12-01

    Recently the Italian Department of Civil Protection (DPC), in cooperation with Istituto Nazionale di Geofisica e Vulcanologia (INGV) has promoted the 'S2' research project (http://nuovoprogettoesse2.stru.polimi.it/) aimed at the design, testing and application of an open-source code for seismic hazard assessment (SHA). The tool envisaged will likely differ in several important respects from an existing international initiative (Open SHA, Field et al., 2003). In particular, while "the OpenSHA collaboration model envisions scientists developing their own attenuation relationships and earthquake rupture forecasts, which they will deploy and maintain in their own systems" , the main purpose of S2 project is to provide a flexible computational tool for SHA, primarily suited for the needs of DPC, which not necessarily are scientific needs. Within S2, a crucial issue is to make alternative approaches available to quantify the ground motion, with emphasis on the near field region. The SHA architecture envisaged will allow for the use of ground motion descriptions other than those yielded by empirical attenuation equations, for instance user generated motions provided by deterministic source and wave propagation simulations. In this contribution, after a brief presentation of Project S2, we intend to illustrate some preliminary 3D scenario simulations performed in the alluvial basin of Sulmona (Central Italy), as an example of the type of descriptions that can be handled in the future SHA architecture. In detail, we selected some seismogenic sources (from the DISS database), believed to be responsible for a number of destructive historical earthquakes, and derive from them a family of simplified geometrical and mechanical source models spanning across a reasonable range of parameters, so that the extent of the main uncertainties can be covered. Then, purely deterministic (for frequencies Element (SE) method, extensively published by Faccioli and his co-workers, and

  4. Moist-soil seed abundance in managed wetlands in the Mississippi Alluvial Valley

    Science.gov (United States)

    Kross, J.; Kaminski, R.M.; Reinecke, K.J.; Penny, E.J.; Pearse, A.T.

    2008-01-01

    Managed moist-soil units support early succession herbaceous vegetation that produces seeds, tubers, and other plant parts used by waterfowl in the Mississippi Alluvial Valley (MAV), USA. We conducted a stratified multi-stage sample survey on state and federal lands in the MAV of Arkansas, Louisiana, Mississippi, and Missouri during autumns 2002?2004 to generate a contemporary estimate of combined dry mass of seeds and tubers (herein seed abundance) in managed moist-soil units for use by the Lower Mississippi Valley Joint Venture (LMVJV) of the North American Waterfowl Management Plan. We also examined variation in mean seed abundance among moist-soil units in 2003 and 2004 in relation to management intensity (active or passive), soil pH and nutrient levels, proportional occurrence of plant life-forms (e.g., grass, flatsedge, and forb; vine; woody plants), and unit area. Estimates of mean seed abundance were similar in 2002 (X over bar = 537.1 kg/ha, SE = 100.1) and 2004 (X over bar = 555.2 kg/ha, SE = 105.2) but 35?40% less in 2003 (X over bar = 396.8 kg/ha, SE = 116.1). Averaged over years, seed abundance was 496.3 kg/ha (SE = 62.0; CV = 12.5%). Multiple regression analysis indicated seed abundance varied among moist-soil units inversely with proportional occurrence of woody vegetation and unit area and was greater in actively than passively managed units (R2adj = 0.37). Species of early succession grasses occurred more frequently in actively than passively managed units (P < 0.09), whereas mid- and late-succession plants occurred more often in passively managed units (P < 0.02). We recommend the LMVJV consider 556 kg/ha as a measure of seed abundance for use in estimating carrying capacity in managed moist-soil units on public lands in the MAV. We recommend active management of moist-soil units to achieve maximum potential seed production and further research to determine recovery rates of seeds of various sizes from core samples and the relationship between

  5. River path selection in response to uplift and interaction with alluvial fans

    Science.gov (United States)

    Grimaud, J. L.; Paola, C.; Voller, V. R.

    2015-12-01

    River systems construct stratigraphic successions and build land by depositing and redistributing sediments as they migrate across the entire basin. This mobility arises from the intrinsic variability of a river system but can also be forced by external changes. It is particularly observable in tectonically active basins where the basement can be partly uplifted and where sediments can come from multiple sources. Theoretically, the ability of these perturbations to steer channels depends on their capacity to create lateral topographic gradients at a faster rate than the aggradation. Following these lines, we present an experimental study on the impacts of lateral tilting by tectonics and lateral alluvial fans on rivers path. The experiment was conducted in the eXperimental Earth Scape facility, also known as the Jurassic tank, where the basement tilting rate can be monitored by controlling individually gravel subsidence through 108 hexagonal cells. The basin was relatively uplifted on one side of the tank according to an anticline-shape and sediments were input through two sources: a main, axial one and a lateral, secondary one. We analyzed the differences in the topographic signature and flow occupation of rivers in response to the uplift or the lateral sediment source as well as the competition of these forcing in the late stages of the experiments. We found that both tectonic tilting and fan activity tend to decrease the basin-wide channel mobility. Indeed, the area at the convergence of the two interacting fans is a long-lasting topographic low that tends to channelize the flow while areas away from it are less visited. The position of this boundary is correlated with the relative flow contribution from both fans. This highlights the self-healing capacity of fans that are able to rapidly restore a graded shape. As opposed to fans, an uplifted area will not heal but force rivers to carve long-lasting valleys and increase the relief. When eroded, these uplifted

  6. Supercritical sheetflood deposits on the volcaniclastic alluvial fan: the Cretaceous upper Daeri Member, Wido Island, Korea

    Science.gov (United States)

    Gul Hwang, In; Gihm, Yong Sik; Kim, Min Cheol

    2016-04-01

    The upper Daeri Member is composed of subaerial primary and resedimented pyroclastic deposits. The upper Daeri Member accumulated under influence of tectonic subsidence, and the basin was divided into four blocks (Block 1 to 4) by intrabasinal normal faults (Fault A to C). Vertical separation of Fault B is estimated about 250 m and provided sufficient accommodation space on Block 3 with intrabasinal physiographic relief, resulting in conformable stacking of the upper Daeri Member on a volcaniclastic alluvial fan. The welded pumiceous lapilli tuff (primary one) was deposited by a pyroclastic density current during an explosive volcanic eruption. After the eruption, the resedimented pyroclastic deposits were deposited by episodic sediment gravity flows and are intercalated with the reddish, homogeneous mudstones. In Block 3 the resedimented pyroclastic deposits show an abrupt decrease in ten largest lithic clasts from within 3 km away from Fault B, reflecting rapid waning of parental sediment gravity flows. A wavy bedded lapilli tuff is one of the lithofacies of the resedimented pyroclastic deposits. The wavy bedded lapilli tuff is composed of symmetrical or nearly-symmetrical, wavy stratifications, forming undulatory bed geometry. The wavy stratifications are recognized by distinctive alternations of few cm to 10 cm thick, lapilli-rich and ash-rich layers. Beds of the wavy bedded lapilli tuff are 0.1 to 2 m thick (estimated in crests) and range in wavelength 1.3 m to 12 m (ave. 8 m). Both amplitude and wavelength gradually decrease away from Fault B. The wavy bedded lapilli tuff can laterally be traced over 90 m. Based on undulatory bed geometry and wavy stratifications, the wavy bedded lapilli tuff is interpreted as antidune bedforms, formed by supercritical sheetfloods. The symmetrical or nearly symmetrical wavy stratifications are due to maintenance of stationary state of standing waves of the sheetfloods. A down current decrease in both wavelength and thickness

  7. Tree growth and recruitment in a leveed floodplain forest in the Mississippi River Alluvial Valley, USA

    Science.gov (United States)

    Gee, Hugo K.W.; King, Sammy L.; Keim, Richard F.

    2014-01-01

    Flooding is a defining disturbance in floodplain forests affecting seed germination, seedling establishment, and tree growth. Globally, flood control, including artificial levees, dams, and channelization has altered flood regimes in floodplains. However, a paucity of data are available in regards to the long-term effects of levees on stand establishment and tree growth in floodplain forests. In this study, we used dendrochronological techniques to reconstruct tree recruitment and tree growth over a 90-year period at three stands within a ring levee in the Mississippi River Alluvial Valley (MAV) and to evaluate whether recruitment patterns and tree growth changed following levee construction. We hypothesized that: (1) sugarberry is increasing in dominance and overcup oak (Quercus lyrata) is becoming less dominant since the levee, and that changes in hydrology are playing a greater role than canopy disturbance in these changes in species dominance; and (2) that overcup oak growth has declined following construction of the levee and cessation of overbank flooding whereas that of sugarberry has increased. Recruitment patterns shifted from flood-tolerant overcup oak to flood-intolerant sugarberry (Celtis laevigata) after levee construction. None of the 122 sugarberry trees cored in this study established prior to the levee, but it was the most common species established after the levee. The mechanisms behind the compositional change are unknown, however, the cosmopolitan distribution of overcup oak during the pre-levee period and sugarberry during the post-levee period, the lack of sugarberry establishment in the pre-levee period, and the confinement of overcup oak regeneration to the lowest areas in each stand after harvest in the post-levee period indicate that species-specific responses to flooding and light availability are forcing recruitment patterns. Overcup oak growth was also affected by levee construction, but in contrast to our hypothesis, growth actually

  8. Surface processes on a mud-dominated Mars analogue alluvial fan, Atacama Desert, northern Chile

    Science.gov (United States)

    Hobley, D. E.; Howard, A. D.; Morgan, A. M.; Matsubara, Y.; Moore, J. M.; Parsons, R.; Williams, R. M.; Burr, D. M.; Hayes, A. G.; Dietrich, W.

    2012-12-01

    We characterize surface processes on highly unusual terrestrial alluvial fans, which we interpret as a strong analogue for large fans on Mars. The Mars fans date to post-Noachian periods when the martian climate was dominated by cold, hyperarid conditions. Some of the martian fans are differentially eroded to leave their distributary channels in positive relief. This inversion, along with the lack of boulders visible on most fan surfaces, reveals that the dominant grain size of the fans is fine enough for the overbank deposits to be stripped by wind. Degradation, image resolution, and lack of ground truthing all act to obscure the nature of the past flow processes. The fans in the Pampa de Tamarugal of the Atacama Desert of northern Chile are excellent potential Mars analogues for a number of reasons: 1. Hyperaridity, with ~2 mm/y rainfall over the fans themselves, resulting in 2. very little vegetation, 3. no fluvial erosion on the fans themselves, and 4. wind-driven erosion of the fan surfaces; 5. equivalent fan scale (tens of km); 6. similar fan gradient (low); 7. low channel branching density; 8. runoff fed from adjacent, much steeper terrain receiving more precipitation (~500 km2 drainages receiving 0.1-1 m/y precipitation in the High Andes, crater walls and interpreted orographic effects on Mars). Both the modern channels and the preserved stratigraphy are dominated by debris flow-like sheetflow mud deposits. Channels are leveed by concrete-like mass-supported deposits of granules and sand suspended in a silt and clay matrix, often overtopping the channel margins and forming up to 150 m wide levees and km-length sheet flows. This leveeing strongly constrains the aggrading channel, which is typically dominated by better sorted and imbricated fluvial deposits. We infer that the wetter tail of mudlfows sorts the deposits, keeping the central channel unblocked by mud. Relatively few channels are active at any time, but aggradation triggers occasional avulsions

  9. Cretaceous mantle of the Congo craton: Evidence from mineral and fluid inclusions in Kasai alluvial diamonds

    Science.gov (United States)

    Kosman, Charles W.; Kopylova, Maya G.; Stern, Richard A.; Hagadorn, James W.; Hurlbut, James F.

    2016-11-01

    Alluvial diamonds from the Kasai River, Democratic Republic of the Congo (DRC) are sourced from Cretaceous kimberlites of the Lucapa graben in Angola. Analysis of 40 inclusion-bearing diamonds provides new insights into the characteristics and evolution of ancient lithospheric mantle of the Congo craton. Silicate inclusions permitted us to classify diamonds as peridotitic, containing Fo91-95 and En92-94, (23 diamonds, 70% of the suite), and eclogitic, containing Cr-poor pyrope and omphacite with 11-27% jadeite (6 diamonds, 18% of the suite). Fluid inclusion compositions of fibrous diamonds are moderately to highly silicic, matching compositions of diamond-forming fluids from other DRC diamonds. Regional homogeneity of Congo fibrous diamond fluid inclusion compositions suggests spatially extensive homogenization of Cretaceous diamond forming fluids within the Congo lithospheric mantle. In situ cathodoluminescence, secondary ion mass spectrometry and Fourier transform infrared spectroscopy reveal large heterogeneities in N, N aggregation into B-centers (NB), and δ13C, indicating that diamonds grew episodically from fluids of distinct sources. Peridotitic diamonds contain up to 2962 ppm N, show 0-88% NB, and have δ13C isotopic compositions from - 12.5‰ to - 1.9‰ with a mode near mantle-like values. Eclogitic diamonds contain 14-1432 ppm N, NB spanning 29%-68%, and wider and lighter δ13C isotopic compositions of - 17.8‰ to - 3.4‰. Fibrous diamonds on average contain more N (up to 2976 ppm) and are restricted in δ13C from - 4.1‰ to - 9.4‰. Clinopyroxene-garnet thermobarometry suggests diamond formation at 1350-1375 °C at 5.8 to 6.3 GPa, whereas N aggregation thermometry yields diamond residence temperatures between 1000 and 1280 °C, if the assumed mantle residence time is 0.9-3.3 Ga. Integrated geothermobaromtery indicates heat fluxes of 41-44 mW/m2 during diamond formation and a lithosphere-asthenosphere boundary (LAB) at 190-210 km. The hotter

  10. Vertical Gradients in Water Chemistry and Age in the Northern High Plains Aquifer, Nebraska, 2003

    Science.gov (United States)

    McMahon, P.B.; Böhlke, J.K.; Carney, C.P.

    2007-01-01

    The northern High Plains aquifer is the primary source of water used for domestic, industrial, and irrigation purposes in parts of Colorado, Kansas, Nebraska, South Dakota, and Wyoming. Despite the aquifer's importance to the regional economy, fundamental ground-water characteristics, such as vertical gradients in water chemistry and age, remain poorly defined. As part of the U.S. Geological Survey's National Water-Quality Assessment Program, water samples from nested, short-screen monitoring wells installed in the northern High Plains aquifer were analyzed for major ions, nutrients, trace elements, dissolved organic carbon, pesticides, stable and radioactive isotopes, dissolved gases, and other parameters to evaluate vertical gradients in water chemistry and age in the aquifer. Chemical data and tritium and radiocarbon ages show that water in the aquifer was chemically and temporally stratified in the study area, with a relatively thin zone of recently recharged water (less than 50 years) near the water table overlying a thicker zone of older water (1,800 to 15,600 radiocarbon years). In areas where irrigated agriculture was an important land use, the recently recharged ground water was characterized by elevated concentrations of major ions and nitrate and the detection of pesticide compounds. Below the zone of agricultural influence, major-ion concentrations exhibited small increases with depth and distance along flow paths because of rock/water interactions. The concentration increases were accounted for primarily by dissolved calcium, sodium, bicarbonate, sulfate, and silica. In general, the chemistry of ground water throughout the aquifer was of high quality. None of the approximately 90 chemical constituents analyzed in each sample exceeded primary drinking-water standards. Mass-balance models indicate that changes in ground-water chemistry along flow paths in the aquifer can be accounted for by small amounts of feldspar and calcite dissolution; goethite and

  11. Geoarchaeologic and paleopedologic evidences for the holocene paleoenvironmental evolution of the Crisuri plain (Western Romania

    Directory of Open Access Journals (Sweden)

    Nicolae Josan

    2007-12-01

    şuri (Fig. 2. Entre les rivières Crisul Repede et Crisul Negruest, les sites sont localisés le long d'une ligne nord-sud qui délimite un système de glacis et de terrasses développé au-dessus de 110 m d'altitude. On peut supposer que cette région a été préférée par les fermiers néolithiques à cause du réseau hydrographique stabilisé, de l'extension des surfaces planes relativement peu exposées aux inondations et de la présence de diverses ressources. Les vestiges laissés dans les sols par les activités humaines fournissent des informations sur les conditions paléoenvironnementales de la morphogenèse. De nombreux sites archéologiques de la Plaine de Crişuri sont susceptibles d'établir les caractéristiques du climat ancien : Girişu de Criş, Salca, Râpa (près de Tinca, Cefa, etc.Le site de Girişu de Criş est situé à l'extérieur du village du même nom, à 16 km à l'ouest d'Oradea, sur la rive droite de la rivière Crişul Repede. Un profil, ouvert jusqu'à 1,5 m de profondeur, met en évidence, à 30-40 cm de profondeur, la couche archéologique Basarabi (Hallstatt-C, 600-800 avant J.C.. C'est un horizon fortement argileux qui contient des bioaccumulations. Sous le premier horizon, à caractère humique, se trouve un horizon alluvial de couleur jaune (40-50 cm formé par des sables fins, qui recouvre à son tour un horizon de couleur noire (20-40 cm correspondant à un tchernoziom dans lequel ont été découverts des fragments de céramiques appartenant à la culture de Coţofeni (le commencement de l'Âge du Bronze. Sous ce dernier horizon se trouve le matériel parental formé par des argiles sableuses de couleur jaune (Fig. 3. La présence du sol noir contenant la culture Coţofeni (synchrone de la culture Pecel de Hongrie et Boden Retz d'Allemagne, datée de la période 3200-3500 avant J.C. correspond à la séquence pédologique spécifique de la stratigraphie de la plaine alluviale de l'Europe Centrale, qui a été d

  12. Subsurface structure of the East Bay Plain ground-water basin: San Francisco Bay to the Hayward fault, Alameda County, California

    Science.gov (United States)

    Catchings, R.D.; Borchers, J.W.; Goldman, M.R.; Gandhok, G.; Ponce, D.A.; Steedman, C.E.

    2006-01-01

    The area of California between the San Francisco Bay, San Pablo Bay, Santa Clara Valley, and the Diablo Ranges (East Bay Hills), commonly referred to as the 'East Bay', contains the East Bay Plain and Niles Cone ground-water basins. The area has a population of 1.46 million (2003 US Census), largely distributed among several cities, including Alameda, Berkeley, Fremont, Hayward, Newark, Oakland, San Leandro, San Lorenzo, and Union City. Major known tectonic structures in the East Bay area include the Hayward Fault and the Diablo Range to the east and a relatively deep sedimentary basin known as the San Leandro Basin beneath the eastern part of the bay. Known active faults, such as the Hayward, Calaveras, and San Andreas pose significant earthquake hazards to the region, and these and related faults also affect ground-water flow in the San Francisco Bay area. Because most of the valley comprising the San Francisco Bay area is covered by Holocene alluvium or water at the surface, our knowledge of the existence and locations of such faults, their potential hazards, and their effects on ground-water flow within the alluvial basins is incomplete. To better understand the subsurface stratigraphy and structures and their effects on ground-water and earthquake hazards, the U.S. Geological Survey (USGS), in cooperation with the East Bay Municipal Utility District (EBMUD), acquired a series of high-resolution seismic reflection and refraction profiles across the East Bay Plain near San Leandro in June 2002. In this report, we present results of the seismic imaging investigations, with emphasis on ground water.

  13. Sufficiency and Deficiency Indices of Soil Available Zinc for Rice in the Alluvial Soil of the Coastal Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To determine the sufficiency and deficiency indices of soil available Zn by the Agro Services International (ASI) method (ASI-Zn) for Zn fertilizer recommendation in rice production in the alluvial soil of the coastal Yellow Sea, the relationship between relative rice yield and soil available ASI-Zn concentration was analyzed from a ten-field experiment with various soil test classes ranging from low to high fertility in 2005 and 2006, and nine Zn fertilizer application rates (0, 7.5,15, 22.5, 30, 37.5, 45, 52.5 and 60 kg Zn/ha) arranged at random with three replications in each field. There was a significant quadratic relationship between soil available ASI-Zn and rice yield, and a significant linear relationship between soil available ASI-Zn concentration and Zn fertilization rate. For rice variety Wuyujing 3, soil available ASI-Zn was deficient when the value was at lower than 1 mg Zn/L, low at 1 to 2 mg Zn/L, sufficient at 1 to 2 mg Zn/L, excessive at higher than 7.5 mg Zn/L. Thus, Zn fertilizer recommendation could be done according to the sufficiency and deficiency indices of soil ASI-Zn. For most of alluvial soils of the coastal Yellow Sea in the study, the available ASI-Zn was lower than 1 mg Zn/L, and then the optimum application rate of Zn fertilizer was about 20 kg Zn/ha.

  14. Using direct current resistivity sounding and geostatistics to aid in hydrogeological studies in the Choshuichi alluvial fan, Taiwan.

    Science.gov (United States)

    Yang, Chieh-Hou; Lee, Wei-Feng

    2002-01-01

    Ground water reservoirs in the Choshuichi alluvial fan, central western Taiwan, were investigated using direct-current (DC) resistivity soundings at 190 locations, combined with hydrogeological measurements from 37 wells. In addition, attempts were made to calculate aquifer transmissivity from both surface DC resistivity measurements and geostatistically derived predictions of aquifer properties. DC resistivity sounding data are highly correlated to the hydraulic parameters in the Choshuichi alluvial fan. By estimating the spatial distribution of hydraulic conductivity from the kriged well data and the cokriged thickness of the correlative aquifer from both resistivity sounding data and well information, the transmissivity of the aquifer at each location can be obtained from the product of kriged hydraulic conductivity and computed thickness of the geoelectric layer. Thus, the spatial variation of the transmissivities in the study area is obtained. Our work is more comparable to Ahmed et al. (1988) than to the work of Niwas and Singhal (1981). The first "constraint" from Niwas and Singhal's work is a result of their use of linear regression. The geostatistical approach taken here (and by Ahmed et al. [1988]) is a natural improvement on the linear regression approach.

  15. Diamonds from the Machado River alluvial deposit, Rondônia, Brazil, derived from both lithospheric and sublithospheric mantle

    Science.gov (United States)

    Burnham, A. D.; Bulanova, G. P.; Smith, C. B.; Whitehead, S. C.; Kohn, S. C.; Gobbo, L.; Walter, M. J.

    2016-11-01

    Diamonds from the Machado River alluvial deposit have been characterised on the basis of external morphology, internal textures, carbon isotopic composition, nitrogen concentration and aggregation state and mineral inclusion chemistry. Variations in morphology and features of abrasion suggest some diamonds have been derived directly from local kimberlites, whereas others have been through extensive sedimentary recycling. On the basis of mineral inclusion compositions, both lithospheric and sublithospheric diamonds are present at the deposit. The lithospheric diamonds have clear layer-by-layer octahedral and/or cuboid internal growth zonation, contain measurable nitrogen and indicate a heterogeneous lithospheric mantle beneath the region. The sublithospheric diamonds show a lack of regular sharp zonation, do not contain detectable nitrogen, are isotopically heavy (δ13CPDB predominantly - 0.7 to - 5.5) and contain inclusions of ferropericlase, former bridgmanite, majoritic garnet and former CaSiO3-perovskite. This suggests source lithologies that are Mg- and Ca-rich, probably including carbonates and serpentinites, subducted to lower mantle depths. The studied suite of sublithospheric diamonds has many similarities to the alluvial diamonds from Kankan, Guinea, but has more extreme variations in mineral inclusion chemistry. Of all superdeep diamond suites yet discovered, Machado River represents an end-member in terms of either the compositional range of materials being subducted to Transition Zone and lower mantle or the process by which materials are transferred from the subducted slab to the diamond-forming region.

  16. Ground motions around a semi-circular valley partially filled with an inclined alluvial layer under SH-polarized excitation

    Science.gov (United States)

    Chang, Kao-Hao; Tsaur, Deng-How; Wang, Jeen-Hwa

    2014-12-01

    A simplified mathematical model, composed of a semi-circular valley partially filled with an inclined alluvial layer under plane SH-wave incidence, is presented. To evaluate the site response theoretically, a rigorous series solution is derived via the region-matching technique. For angular wavefunctions constrained by an inclined free surface, the original form of Graf's addition formula is recast to arbitrarily shift the local coordinate system. The valley geometry, filling material, angle of incidence, and wave frequency are taken as significant parameters in exploring the site effect on ground motions. Also included are the frequency- and time-domain computations. Two canonical cases, the semi-circular vacant canyon and the fully filled semi-circular alluvial valley, with exact analytical solutions, and the partly horizontally filled case previously studied, are taken to be particular cases of the proposed general model. Steady-state results show that the peak amplitudes of motion may increase at low frequencies when the filling layer inclines to the illuminated region. At low-grazing incidence, the phenomenon of wave focusing becomes evident on the shadow side of the filling layer. Transient-state simulations elucidate how a sequence of surface waves travel on the topmost alluvium along opposite directions and interfere with multiple reflected waves within the filling layer.

  17. Wetland Reserve Program enhances site occupancy and species richness in assemblages of anuran amphibians in the Mississippi Alluvial Valley, USA

    Science.gov (United States)

    Walls, Susan C.; Waddle, J. Hardin; Faulkner, Stephen P.

    2014-01-01

    We measured amphibian habitat use to quantify the effectiveness of conservation practices implemented under the Wetland Reserve Program (WRP), an initiative of the U.S. Department of Agriculture’s Natural Resources Conservation Service. From February to June 2007, we quantified calling male anurans in cultivated cropland, former cultivated cropland restored through the WRP, and mature bottomland hardwood forest. Sites were located in two watersheds within the Mississippi Alluvial Valley of Arkansas and Louisiana, USA. We estimated detection probability and site occupancy within each land use category using a Bayesian hierarchical model of community species occurrence, and derived an estimate of species richness at each site. Relative to sites in cultivated cropland, nine of 1 l species detected were significantly more likely to occur at WRP sites and six were more likely to occur at forested sites. Species richness estimates were also higher for WRP and forested sites, compared to those in cultivated cropland. Almost half (45 %) of the species responded positively to both WRP and forested sites, indicating that patches undergoing restoration may be important transitional habitats. Wetland Reserve Program conservation practices are successful in restoring suitable habitat and reducing the impact of cultivation-induced habitat loss on amphibians in the Mississippi Alluvial Valley.

  18. Chronology of processes in high-gradient channels of medium-high mountains and their influence on the properties of alluvial fans

    Science.gov (United States)

    Šilhán, Karel

    2014-02-01

    High-gradient channels are the locations of the greatest geomorphological activity in medium-high mountains. The channels' frequency and character influence the contemporary morphology and morphometry of alluvial fans. There is currently no detailed information regarding the frequency of these processes in high-gradient channels and the evolution of alluvial fans in medium-high mountains in Central Europe. This study in the Moravskoslezské Beskydy Mts. analysed 22 alluvial fans (10 debris flow fans and 12 fluvial fans). The processes occurring on the fans were dated using dendrogeomorphological methods. A total of 748 increment cores were taken from 374 trees to reconstruct 153 geomorphological process events (60 debris flow and 93 floods). The frequency of the processes has been considerably increasing in the last four decades, which can be related to extensive tree cutting since the 1970s. Processes in high-gradient channels in the region (affecting the alluvial fans across the mountain range) are predominantly controlled by cyclonal activity during the warm periods of the year. Probable triggers of local events are heavy downpours in the summer. In addition, spring snowmelt has been identified as occasionally important. This study of the relations affecting the type and frequency of the processes and their effect on the properties of alluvial fans led to the creation of a universal framework for the medium-high flysch mountains of Central Europe. The framework particularly reflects the influence of the character of hydrometeorological extremes on the frequency and type of processes and their reflection in the properties of alluvial fans.

  19. Radiopaque intrahepatic duct stones in plain radiograph: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Young; Suh, Chang Hae; Park, Chan Sup; Chung, Won Kyun [College of Medicine, Inha University, Seongnam (Korea, Republic of)

    1994-04-15

    We experienced 3 cases of intrahepatic duct stones detected on plain radiographs. The patients had history of multiple episodes of recurrent cholangitis. Radiographic characteristics of these stones included multiple, round or rectangular radiopaque densities surrounded by calcified rim; these densities showed a branching pattern along the intrahepatic ducts.

  20. 19th Century Plains Indian Robe Painting: Wearable Art Form.

    Science.gov (United States)

    McMaster, Gerald R.

    1983-01-01

    The Indians of the Great Plains of North America once wore some of the most magnificent works of art in the form of bison robes that were painted in a variety of modes. These forms of expression have become obsolete and their function has been replaced by new materials. (Availability: CHEA National Office, 151 Slater Street, Ottawa, Ontario K1P…

  1. Research on Fish Consumer Profile Evaluation in Romanian Plain Area

    Directory of Open Access Journals (Sweden)

    Silvius STANCIU

    2011-11-01

    Full Text Available Research aimed at shaping a fish consumer profile in the Romanian Plain area. 150 people were interviewed. Preferences evaluation was conducted by means of a questionnaire with 27 questions. Favorite fish species, purchasing place and manner, favorite preparation choices, consumption frequency and place have been identified.

  2. Regional dynamics of grassland change in the western Great Plains

    Science.gov (United States)

    Drummond, M.A.

    2007-01-01

    This paper examines the contemporary land-cover changes in two western Great Plains ecoregions between 1973 and 2000. Agriculture and other land uses can have a substantial effect on grassland cover that varies regionally depending on the primary driving forces of change. In order to better understand change, the rates, types, and causes of land conversion were examined for 1973, 1980, 1986, 1992, and 2000 using Landsat satellite data and a statistical sampling strategy. The overall estimated rate of land-cover change between 1973 and 2000 was 7.4% in the Northwestern Great Plains and 11.5% in the Western High Plains. Trends in both ecoregions have similarities, although the dynamics of change differ temporally depending on driving forces. Between 1973 and 1986, grassland cover declined when economic opportunity drove an expansion of agriculture. Between 1986 and 2000, grassland expanded as public policy and a combination of socioeconomic factors drove a conversion from agriculture to grassland. ?? 2007 Copyright by the Center for Great Plains Studies, University of Nebraska-Lincoln.

  3. Rural School District Reorganization on the Great Plains.

    Science.gov (United States)

    Bryant, Miles

    2002-01-01

    Rural school district reorganization and school consolidation are put into perspective by reviewing the large population increases that fueled small-school growth in the Great Plains, 1870-1930. Since the Dust Bowl and Great Depression, population losses, improvements in transportation, and arguments advocating economies of scale and increased…

  4. Acanthosis Nigricans among Northern Plains American Indian Children

    Science.gov (United States)

    Brown, Blakely; Noonan, Curtis; Bentley, Bonnie; Conway, Kathrene; Corcoran, Mary; FourStar, Kris; Gress, Shannon; Wagner, Sharon

    2010-01-01

    The purpose of this study is to present cross-sectional and prospective data on acanthosis nigricans (AN) prevalence in the context of other risk factors for diabetes including high body mass index (BMI), abnormal blood pressure (BP), physical inactivity and family history of diabetes among Northern Plains American Indian (AI) children.…

  5. Trichobezoars Detected and Treated Based on Plain Radiography.

    Science.gov (United States)

    Barrows, Amy; Vachon, Tyler; Campin, Richard C; Ignacio, Romeo C

    2015-10-01

    Bezoars are conglomerations of indigestible material that become trapped in the gastrointestinal tract. We present a case of an 8-year-old female child diagnosed with a gastric bezoar solely on plain radiography and treated with abdominal surgical exploration and removal. In addition, traditional characteristic radiographic findings and treatment options for bezoars found in the current literature are reviewed.

  6. Introducing Plain Language Principles to Business Communication Students

    Science.gov (United States)

    Greer, Rachelle R.

    2012-01-01

    In response to current federal mandates requiring selected businesses and government agencies to use plain language (PL) when reporting information to the public, this article advocates the introduction of PL principles into current business communication curricula. Despite recent PL mandates and advances, many current business textbooks and…

  7. Aerial Images of Alaska's Arctic Coastal Plain; 1948, 1949

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is comprised of 36 black and white 9x9 inch aerial images of four different study areas on Alaska's Arctic Coastal Plain taken between 1948-1949 and...

  8. Aerial Image of Alaska's Arctic Coastal Plain; 1955

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is comprised of a single aerial image of a single area on Alaska's Arctic Coastal Plain taken on 21 June 1955 by the U.S. Air Force and obtained from...

  9. Deathscapes, Topocide, Domicide: The Plains in Contemporary Print Media

    Science.gov (United States)

    Dando, Christina E.

    2009-01-01

    The American print media are a powerful mechanism for communicating information about places and environment to the American public. When it comes to a landscape such as the Great Plains, experienced by many Americans as either sleep-through land in a car or flyover land in a plane, the print media may be their only real source of information…

  10. Flour Flame Thrower: The "Flaming Potential" of Plain Flour

    Science.gov (United States)

    Sandoval, Christopher

    2012-01-01

    Plain flour has a lot of chemical energy packed into it. When the flour is in a clump or pile it does not ignite although it may blacken. This is because there is not enough flour exposed to the oxygen in the air. Aerosolising the flour exposes it to much more oxygen allowing a self sustaining combustion reaction to occur when an ignition source…

  11. The Past, Present, and Future of Plain English.

    Science.gov (United States)

    Felsenfeld, Carl

    1987-01-01

    The "plain English" movement began in 1975 when Citibank of New York introduced the first simplified promissory note. This led to much legislative activity and reform in the area of writing for consumers. The new challenge will be to simplify "computerese." (Author/CH)

  12. Martensite Formation in Partially and Fully Austenitic Plain Carbon Steels

    NARCIS (Netherlands)

    Van Bohemen, S.M.C.; Sietsma, J.

    2009-01-01

    The progress of martensite formation in plain carbon steels Fe-0.46C, Fe-0.66C, and Fe-0.80C has been investigated by dilatometry. It is demonstrated that carbon enrichment of the remaining austenite due to intercritical annealing of Fe-0.46C and Fe-0.66C does not only depress the start temperature

  13. Educational enhancements to the Texas High Plains Evapotranspiration (ET) network

    Science.gov (United States)

    In this study, an irrigation scheduling and management tool was developed for addressing large acreage and multiple field irrigated farms, particularly those in the Texas High Plains where the declining Ogallala Aquifer is the primary source of irrigation water. This tool, while providing in-season ...

  14. Semantic and pragmatic functions in Plains Cree syntax

    NARCIS (Netherlands)

    Wolvengrey, A.E.

    2011-01-01

    This dissertation explores the morphosyntax of the Plains dialect of Cree - an Algonquian First Nations language of Canada - and the ways in which Semantic, Pragmatic and Syntactic Functions are (or are not) instantiated. The language-specific forms of two main morphosyntactic components of language

  15. The Renewal of Population Loss in the Nonmetropolitan Great Plains.

    Science.gov (United States)

    Albrecht, Don E.

    1993-01-01

    Analysis of population trends in 293 nonmetropolitan counties in the Great Plains, 1950-90, reveals that the rural population turnaround of the 1970s has indeed ended. During the 1980s, 84% of these counties had total population declines, and 96% had net outmigration. The most important variable in producing positive trends was inmigration of…

  16. The Horse and the Plains Indian. Indian Culture Series.

    Science.gov (United States)

    Schuessler, Raymond

    Produced by the Montana Council for Indian Education as part of its Indian Culture Series, the five short articles in the book explain how the Plains Indians got horses in legend and in fact. The stories describe the behavior codes, rules, cultural and social significance, and eventual cessation of horse raids, and the ceremony and tradition…

  17. Lichens in the rural landscape of the Warmia Plain

    Directory of Open Access Journals (Sweden)

    Rafał Szymczyk

    2013-12-01

    Full Text Available Lichens and lichenicolous fungi in the rural landscape of the Warmia Plain were studied. Lichen species were observed on old wooden fences, roadside trees, fruit trees, pylons, farm machinery, buildings and bridges. The analysed biota consists of 104 taxa with several noteworthy and rare lichens.

  18. Plains Prickly Pear Cactus Response to Fire and Fuel Loads

    Science.gov (United States)

    Management of prickly pear on rangelands has lead to numerous studies aimed at understanding prickly pear response to various natural and human induced treatments. Information is lacking on Plains prickly pear response to varied fuel loads. Pads of clones from three soil types (claypan, gravel, si...

  19. Astrobiology and the Basaltic Plains in Gusev Crater

    Science.gov (United States)

    DesMarais, D. J.; Clark, B. C.; Crumpler, L. S.; Farmer, J. D.; Grotzinger, John P.; Haskin, Larry A.; Knoll, Andrew H.; Landis, Geoffrey A.; Moersch, Jeffrey; Schroeder, Christian

    2005-01-01

    This report assesses the availability of nutrient elements, energy and liquid water on the plains surrounding Columbia Memorial Station by evaluating observations by the MER rover Spirit in the context of previous Mars missions, Earth-based studies of martian meteorites and studies of microbial communities on Earth that represent potential analogs of martian biota.

  20. Investigations on alluvial deposits through borehole stratigraphy, radiocarbon dating and passive seismic technique (Carnic Alps, NE Italy)

    Science.gov (United States)

    Viero, Alessia; Marchi, Lorenzo; Cavalli, Marco; Crema, Stefano; Fontana, Alessandro; Mozzi, Paolo; Venturini, Corrado

    2016-04-01

    Alluvial sediment investigations provide fundamental tools to infer the processes that control geomorphological evolution of mountain environments. By analyzing sediment stratigraphy in depth, it is possible to retrieve the source, the geology, the time of deposition, the relative distance travelled by material as well as to distinguish among different type of transport (i.e., gravitational, fluvial or glacial). In this work, we present a combination of log stratigraphy, radiocarbon dating and geophysical surveys carried out on the valley floor of the But River (Carnic Alps, North East Italy). The But River basin drains an area of 326 km2 with a range in elevation from 2769 to 323 m a.s.l.; the bedrock mainly consists of carbonates and quartz arenites with minor inclusions of effusive rocks. After Pleistocene the gravitational deposits from mountain slopes have impounded the But River several times. In particular, we analyzed a sector of the upper portion of the But valley close to the confluence of the Moscardo Torrent, frequently affected by debris flows. A borehole was drilled in the But River floodplain, at the intersection with the Moscardo Torrent alluvial fan, down to a depth of 80 m. The analysis of the core samples allowed discerning three sedimentary levels rich in clay and organic materials, which testify the presence of small dam lakes, originated from the Moscardo debris-flow deposits. Three samples of wood and plant debris were collected from 13, 14 and 23 m of depth, respectively. They were analyzed through radiocarbon dating in order to determine the age of the lakes and, thus, to infer the activity of the debris flows building the Moscardo cone. The calibrated ages of the 3 samples are close to the younger limit of the radiocarbon method indicating a fast aggradation of the valley floor, starting from a period ranging between 1450 - 1632 AD. Historical maps and documents confirm the presence of the lakes until 19th century and they permit to assess

  1. An investigation into variable recharge behaviors among eight alluvial observation wells in Pajarito Canyon, Los Alamos, New Mexico

    Science.gov (United States)

    Schmeer, S. R.

    2010-12-01

    Pajarito Canyon in Los Alamos, New Mexico trends west to east through the Pajarito Plateau from the headwaters in the Jemez Mountains, thirteen miles to the Rio Grande. In summer 2008, Los Alamos National Laboratory installed eight shallow wells, numbered PCAO-5, 6, 7a, 7b1, 7b2, 7c, 8 and 9, in the middle four miles of this canyon. Among these wells, five distinct recharge behaviors have been observed. PCAO-5 demonstrates seasonal recharge in response to annual snowmelt. PCAO-6, while just 400 feet further downstream, is considerably flashier and the well is often dry for months at a time. In PCAO-7a, 7b2 and 7c, another two miles downstream, the water level declined steadily since installation, with no recharge until spring 2010. PCAO-7b1 has not contained water since drilling. Downstream a further two miles, PCAO-8 and PCAO-9 were dry for the majority of 2009 and their hydrographs are more attenuated. This investigation was undertaken to explain the recharge behaviors of the wells, with the goal of improving site selection and design of alluvial wells to provide better representation of the alluvial aquifer. Water level data collected since July 2008 were used to compare the water columns of each well. Well construction diagrams were utilized to construct stratigraphic maps in order to compare well construction and lithology. Results indicate that PCAO-5 consistently contains water due to its location above a flood retention structure (FRS) and the placement of its screened interval immediately above the tuff layer, forcing water to travel through the screened interval. PCAO-6’s flashy, intermittent hydrograph is due to its location downstream of the FRS, and because the bottom of the screened interval rests 2.5 feet above the alluvium-tuff interface, providing a conduit below the screen of the well. The similar behaviors of PCAO-7a, 7b2 and 7c result from their near-identical construction, lithology and location. The general decline of water level until

  2. River diversions, avulsions and captures in the Tortuguero coastal plain

    Science.gov (United States)

    Galve, Jorge Pedro; Alvarado, Guillermo; Pérez Peña, José Vicente; Azañón, José Miguel; Mora, Mauricio; Booth-Rea, Guillermo

    2016-04-01

    The Tortuguero area is a coastal plain that forms part of the North Limón sedimentary basin, the back-arc region of the Caribbean side of Costa Rica. This coastal plain is characterised by an abnormal drainage pattern with river captures, diversions and shifts in channel directions. We are analyzing this anomalous drainage network adopting a classical geomorphological approach combined with geomorphometric techniques. The SRTM DEM at 1 arc-second of resolution (~30 m) from NASA, topographic maps 1:50,000, satellital images and the digital cartography of the drainage network have been used for inventorying the channel pattern anomalies. River segments were categorized according to sinuosity, orientation, slope changes and incision using GIS tools. Initially, anomalies in the analyzed river courses suggested that buried thrust fronts could disrupt their natural pattern. However, we have not identified any evidence to link the activity of buried structures with the disruption of natural drainage. Blind thrusts detected through seismic subsurface exploration in the SE sector of the Tortuguero plain do not seem to produce changes in the sinuosity, orientation, slope and incision of rivers as those observed in the deeply studied tectonically active area of the Po Plain (Italy). The identified river pattern anomalies have been explained due to other alternative causes: (1) the migration of the mouths of Reventazón, Pacuare and Matina rivers is produced by sand sedimentation in the coast because of a successive ridge beach formation. This migration to the SE has the same direction than the main ocean currents those deposited the sand. (2) The anomalous course of Parismina river is most probably conditioned by the fracturation of the dissected volcanic apron of Turrialba volcano. (3) Channel migration and capture of Barbilla river by Matina river can be triggered by the tectonic tilting of the coastal plain towards the SE. The subsidence of the SE sector of the plain was

  3. LAND SUITABILITY SCENARIOS FOR ARID COASTAL PLAINS USING GIS MODELING: SOUTHWESTERN SINAI COASTAL PLAIN, EGYPT

    Directory of Open Access Journals (Sweden)

    Ahmed Wahid

    2009-01-01

    Full Text Available Site selection analysis was carried out to find the best suitable lands for development activities in an example of promising coastal plains, southwestern Sinai, Egypt. Two GIS models were developed to represent two scenarios of land use suitability in the study area using GIS Multi Criteria Analysis Modeling. The factors contributed in the analysis are the Topography, Land cover, Existing Land use, Flash flood index, Drainage lines and Water points. The first scenario was to classify the area according to various gradual ranges of suitability. According to this scenario, the area is classified into five classes of suitability. The percentage of suitability values are 51.16, 6.13, 22.32, 18.49 and 1.89% for unsuitable, least suitable, low suitable, suitable and high suitable, respectively. The second scenario is developed for a particular kind of land use planning; tourism and recreation projects. The suitability map of this scenario was classified into five values. Unsuitable areas represent 51.18% of the study area, least suitable 16.67%, low suitable 22.85%, suitable 8.61%, and high suitable 0.68%. The best area for locating development projects is the area surrounding El-Tor City and close to the coast. This area could be an urban extension of El-Tor City with more economical and environmental management.

  4. Dendroclimatic potential of plains cottonwood (Populus deltoides subsp. monilifera) from the Northern Great Plains, USA

    Science.gov (United States)

    Edmonson, Jesse; Friedman, Jonathan; Meko, David; Touchan, Ramzi; Scott, Julian; Edmonson, Alan

    2014-01-01

    A new 368-year tree-ring chronology (A.D. 1643–2010) has been developed in western North Dakota using plains cottonwood (Populus deltoides subsp. monilifera) growing on the relatively undisturbed floodplain of the Little Missouri River in the North Unit of Theodore Roosevelt National Park. We document many slow-growing living trees between 150–370 years old that contradict the common understanding that cottonwoods grow fast and die young. In this northern location, cottonwood produces distinct annual rings with dramatic interannual variability that strongly crossdate. The detrended tree-ring chronology is significantly positively correlated with local growing season precipitation and soil moisture conditions (r  =  0.69). This time series shows periods of prolonged low radial tree growth during the known droughts of the instrumental record (e.g. 1931–1939 and 1980–1981) and also during prehistory (e.g. 1816–1823 and 1856–1865) when other paleoclimate studies have documented droughts in this region. Tree rings of cottonwood will be a useful tool to help reconstruct climate, streamflow, and the floodplain history of the Little Missouri River and other northern river systems.

  5. LAND SUITABILITY SCENARIOS FOR ARID COASTAL PLAINS USING GIS MODELING: SOUTHWESTERN SINAI COASTAL PLAIN, EGYPT

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed Wahid

    2009-12-01

    Full Text Available Site selection analysis was carried out to find the best suitable lands for development activities in an example of promising coastal plains, southwestern Sinai, Egypt. Two GIS models were developed to represent two scenarios of land use suitability in the study area using GIS Multi Criteria Analysis Modeling. The factors contributed in the analysis are the Topography, Land cover, Existing Land use, Flash flood index, Drainage lines and Water points. The first scenario was to classify the area according to various gradual ranges of suitability. According to this scenario, the area is classified into five classes of suitability. The percentage of suitability values are 51.16, 6.13, 22.32, 18.49 and 1.89% for unsuitable, least suitable, low suitable, suitable and high suitable, respectively. The second scenario is developed for a particular kind of land use planning; tourism and recreation projects. The suitability map of this scenario was classified into five values. Unsuitable areas represent 51.18% of the study area, least suitable 16.67%, low suitable 22.85%, suitable 8.61%, and high suitable 0.68%. The best area for locating development projects is the area surrounding El-Tor City and close to the coast. This area could be an urban extension of El-Tor City with more economical and environmental management.

  6. New morpho-stratigraphic constraints for the evolution of the alluvial fan system along the northern slopes of the Taburno-Camposauro Mountains (Calore River basin, Southern Italy)

    Science.gov (United States)

    Leone, Natalia; Amato, Vincenzo; Aucelli, Pietro P. C.; Cesarano, Massimo; Filocamo, Francesca; Petrosino, Paola; Rosskopf, Carmen M.; Valente, Ettore; Giralt, Santiago; Casciello, Emilio

    2016-04-01

    The Lower Calore River Valley is a morphostructural depression located in the inner sector of the Campanian Apennine, between the Taburno-Camposauro and the Matese carbonate massifs. The river is the main left tributary of the Volturno River, it has a meandering channel partially structural-controlled. Numerous morphotectonic clues and historical seismicity data suggest that this part of the Apennine chain was particularly active during the late-Quaternary. In detail, the valley is E-W oriented and presents an asymmetry of the opposed valley slopes. The left side, corresponding to the northern flank of the Camposauro massif, is characterized by a steep slope (70°-35°), partially controlled by a ~E-W oriented fault system, and by a wide less-inclined piedmont aggradation zone. The latter started growing since middle Pleistocene, with the deposition of alluvial fans and slope deposits over the well cemented early Pleistocene breccias of Laiano Synthem. The alluvial fan deposition has been active until present giving rise to three main generations of alluvial fans. The right side of the valley, instead, is characterized by seven orders of fluvial terraces, both of erosional and depositional origin. The quaternary morpho-stratigraphic evolution of alluvial fans and fluvial terraces has been strongly conditioned by the interaction of tectonic phases and climatic variations. A detailed geomorphological study (1:5.000 in scale) was carried out with the aim to map the main depositional and erosional fluvial landforms and to identify the main tectonic lineaments of the area. A detailed field survey allowed to better define the stratigraphic and paleoenvironmental context in which the alluvial deposits developed and also to find chrono-stratigraphic markers. Tephra-stratigraphic analyses were performed on pyroclastic deposits interbedded into the alluvial fan and fluvial successions. At the moment the age of the first generation of alluvial fans is still under

  7. Hydrogeological framework, numerical simulation of groundwater flow, and effects of projected water use and drought for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma

    Science.gov (United States)

    Ryter, Derek W.; Correll, Jessica S.

    2016-01-14

    This report describes a study of the hydrology, hydrogeological framework, numerical groundwater-flow models, and results of simulations of the effects of water use and drought for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma. The purpose of the study was to provide analyses, including estimating equal-proportionate-share (EPS) groundwater-pumping rates and the effects of projected water use and droughts, pertinent to water management of the Beaver-North Canadian River alluvial aquifer for the Oklahoma Water Resources Board.

  8. [Endangered resources and origin changes of Pinellia ternate in Huanghuai plain].

    Science.gov (United States)

    Mu, Er-Ting; Zhou, Jian-Li

    2013-11-01

    The wild Pinellia ternata resource was surveyed by field investigation, visiting surveys combine with literature study and changing factors of the wild P. ternata in the area of Huanghuai Plain were analyzed. The results indicated that Huanghuai Plain wild P. ternata resources were scarce and nearly extinct. The chemical farming methods in Huanghuai Plain have endangered the survival of the wild P. ternata.

  9. Constructing a Home on the Range: Homemaking in Early-Twentieth-Century Plains Photograph Albums

    Science.gov (United States)

    Dando, Christina E.

    2008-01-01

    For people living near the coasts or mountains of America, it must be hard to imagine longing for a "home on the plains"--but many Americans have had, and still have, a home on the Plains. The stereotypical American image of the Plains is flatness, austerity, emptiness. Not all would consider this an ideal landscape for home. So how did the people…

  10. 13 CFR 120.172 - Flood-plain and wetlands management.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Flood-plain and wetlands... Flood-plain and wetlands management. (a) All loans must conform to requirements of Executive Orders 11988, “Flood Plain Management” (3 CFR, 1977 Comp., p. 117) and 11990, “Protection of Wetlands” (3...

  11. Peligro de aluviones en el departamento Pocito, provincia de San Juan Alluvial hazard in the department of Pocito, province of San Juan

    Directory of Open Access Journals (Sweden)

    L.P. Perucca

    2005-03-01

    materials from the outcrops. Most of the piedmont is practically barren of vegetation, so superficial runoff is very rapid.The extent of active areas on the Zonda piedmont have been determined from geomorphology study of aerial photographs and topography. The active areas are inset at lower relative elevations in relations to adjacent ancient piedmont surfaces. In the floodplain, where the urban and rural areas are located, historical floods have been confined to number 13 and 15 streets, that are oriented parallel the downslope direction of the piedmont, with a west-east trend. During rainfalls these streets have been transformed in natural riverbeds that flow through the populated areas, influencing the path of the floods and limiting damages to structures. But streets and irrigation channels with a north-south trending are affected and damage. In this work, an evaluation of hydrologic aspects of torrential La Lechuza creek basin is made. This stream cause the largest of damages in the department.The establishment of a prediction and warning system, public education and structural measures are means to minimize alluvial plain flooding at Pocito department.

  12. Acute paediatric ankle trauma: MRI versus plain radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lohman, M. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Radiological Dept., Helsinki University Central Hospital (Finland); Kivisaari, A.; Kivisaari, L. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Kallio, P.; Puntila, J. [Dept. of Paediatric Surgery, Hospital for Children and Adolescents, Helsinki Univ. Central Hospital, Helsinki (Finland); Vehmas, T. [Finnish Institute of Occupational Health, Helsinki (Finland)

    2001-09-01

    Objective: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. Methods: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three ''masked'' radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. Results: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures. Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter- Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. Conclusions: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries. (orig.)

  13. The role of the uncertainty in assessing future scenarios of water shortage in alluvial aquifers

    Science.gov (United States)

    Romano, Emanuele; Camici, Stefania; Brocca, Luca; Moramarco, Tommaso; Guyennon, Nicolas; Preziosi, Elisabetta

    2015-04-01

    There are many evidences that the combined effects of variations in precipitation and temperature due to climate change can result in a significant change of the recharge to groundwater at different time scales. A possible reduction of effective infiltration can result in a significant decrease, temporary or permanent, of the availability of the resource and, consequently, the sustainable pumping rate should be reassessed. In addition to this, one should also consider the so called indirect impacts of climate change, resulting from human intervention (e.g. augmentation of abstractions) which are feared to be even more important than the direct ones in the medium term: thus, a possible increase of episodes of shortage (i.e. the inability of the groundwater system to completely supply the water demand) can result both from change in the climate forcing and change in the demand. In order to assess future scenarios of water shortage a modelling chain is often used. It includes: 1) the use of General Circulation Models to estimate changes in temperature and precipitation; 2) downscaling procedures to match modeling scenarios to the observed meteorological time series; 3) soil-atmosphere modelling to estimate the time variation of the recharge to the aquifer; 4) groundwater flow models to simulate the water budget and piezometric head evolution; 5) future scenarios of groundwater quantitative status that include scenarios of demand variation. It is well known that each of these processing steps is affected by an intrinsic uncertainty that propagates through the whole chain leading to a final uncertainty on the piezometric head scenarios. The estimate of such an uncertainty is a key point for a correct management of groundwater resources, in case of water shortage due to prolonged droughts as well as for planning purposes. This study analyzes the uncertainty of the processing chain from GCM scenarios to its impact on an alluvial aquifer in terms of exploitation

  14. Evaluating the Quality and Accuracy of TanDEM-X Digital Elevation Models at Archaeological Sites in the Cilician Plain, Turkey

    Directory of Open Access Journals (Sweden)

    Stefan Erasmi

    2014-10-01

    Full Text Available Satellite remote sensing provides a powerful instrument for mapping and monitoring traces of historical settlements and infrastructure, not only in distant areas and crisis regions. It helps archaeologists to embed their findings from field surveys into the broader context of the landscape. With the start of the TanDEM-X mission, spatially explicit 3D-information is available to researchers at an unprecedented resolution worldwide. We examined different experimental TanDEM-X digital elevation models (DEM that were processed from two different imaging modes (Stripmap/High Resolution Spotlight using the operational alternating bistatic acquisition mode. The quality and accuracy of the experimental DEM products was compared to other available DEM products and a high precision archaeological field survey. The results indicate the potential of TanDEM-X Stripmap (SM data for mapping surface elements at regional scale. For the alluvial plain of Cilicia, a suspected palaeochannel could be reconstructed. At the local scale, DEM products from TanDEM-X High Resolution Spotlight (HS mode were processed at 2 m spatial resolution using a merge of two monostatic/bistatic interferograms. The absolute and relative vertical accuracy of the outcome meet the specification of high resolution elevation data (HRE standards from the National System for Geospatial Intelligence (NSG at the HRE20 level.

  15. Nitrate pollution of groundwater in the alsatian plain (France)—A multidisciplinary study of an agricultural area: The Central Ried of the ill river

    Science.gov (United States)

    Bernhard, C.; Carbiener, R.; Cloots, A. R.; Froehlicher, R.; Schenck, Ch.; Zilliox, L.

    1992-09-01

    The area studied is part of the “Ried Central” of the Ill river (Middle Alsatian plain in northeastern France). This area is located mainly in the present floodplain of the Ill. The closeness of the water table to the surface results in quasi general soil hydromorphism. The economic constraints of the last two decades led to deep changes in agricultural activities in the study area. These have essentially involved a marked extension of intensive cultivation of grain corn at the expense of grasslands. The study of the influence of this change on the parallel increase in the concentration of nitrate in groundwater is only feasible when a multidisciplinary approach is adopted. The analyses carried out in the field and in the laboratory show that nitrate reduction occurs in gleyed or peaty horizons of hydromorphic soils. The aptitude and efficiency of the permanent ambient vegetation (alluvial forests and grasslands) in retaining nitrate must be emphasized. The amount of nitrate eliminated from the aquifer by rivers fed by this aquifer is considerable. This evacuation of nitrate into the Ill is a fine example of waste and illustrates the absurdity of the economic situation responsible for excessive nitrogen fertilization of farmlands. In determining hazard zones, this study also proposes practical solutions to the problem of nitrate pollution: diminution of land area under cultivation, reintroduction of grasslands, and a more judicious use of nitrogen manure.

  16. Identification of thick sedimentary plains north of Hellas

    Science.gov (United States)

    Salese, Francesco; Mangold, Nicolas; Ansan, Veronique; Carter, John; Ody, Anouck; Poulet, François; Ori, Gian Gabriele

    2016-04-01

    Understanding the origin and timing of intercrater plains is crucial to understand the Martian history in relation with endogenic and/or exogenic cycles. Intercrater plains north of Hellas basin on Mars are thought to have hosted different sedimentary environments during the Late Noachian/Early Hesperian, and they offer a well-preserved insight into the regional geological history of Mars. Our new geologic mapping of the intercrater plains north of Hellas Basin is based on the rich data set from MRO and Mars Express and provides new insights into the region's geological history. These findings appear to constrain the interpretation of the nature and age of intercrater plains in this region, although we acknowledge that for example the source of the sedimentary deposits must be subject to further analysis. The northern part of Hellas basin displays topographically flat area, which was characterized during the Late Noachian by sedimentary deposition and later, in the Late Hesperian, by fissural volcanism. The map and crater retention ages enable us to interpret the geologic history of the region. The stratigraphically lower unit is represented by crustal outcrops. Across most of the region, the sedimentary unit covers the basement and is eroded into mesas, erosional windows and perched by fresh craters. Intercrater plains' sedimentary deposits north of Hellas display horizontal light-toned layered rich in Fe/Mg-phyllosilicates and local crossbedding stratification. The Noachian sedimentary deposits of the intercrater plains north of Hellas are locally covered by Hesperian lava flows, showing that intercrater plains are sedimentary and volcanic in origin. We found different erosional (regional and local) surfaces, at HiRISE scale inside sediments due to local erosional windows and at CTX scale we found two important regional erosional surfaces. The oldest between crustal outcrops and sediments, which is likely Middle Noachian in age and the youngest between sediments

  17. Controls on morphometry and morphology of alluvial and colluvial fans in the high-Arctic setting, Petuniabukta, Svalbard.

    Science.gov (United States)

    Tomczyk, Aleksandra; Ewertowski, Marek

    2016-04-01

    The Petuniabukta (78o42' N, 16o32') is a bay in the northern part of Billefjorden in the central part of Spitsbergen Island, Svalbard. The bay is surrounded by six major, partly glaciated valleys. A numerous alluvial and colluvial fans have developed within valleys as well as along the fiord margins. Distribution and characterization of morphometric parameters of fans were investigated using time-series of orthophotos and digital elevation models (generated based on 1961, 1990, 2009 aerial photographs) and high resolution satellite imagery from 2013. In addition, a very detailed DEM and orthophoto (5 cm resolution) have been produced from unmanned aerial vehicle (UAV) imagery from 2014 and 2015, covering three fans characterised by different types of surface morphology. A 1:40,000 map showing the distribution of almost 300 alluvial and colluvial fans (ranging in area from 325 km2 to 451 275 km2), together with time-series of 1:5,000 geomorphological maps of sample fans enabled an assessment of the spatial and temporal evolution of processes responsible for delivery and erosion of sediments from the fans. The relationship between terrain parameters (e.g. slope, exposition) as well as geology was also investigated. Many of the studied alluvial fans were at least partly coupled and sediments were transferred from the upstream zone to the downstream zone, either due to debris-flow or channelized stream flow. In other cases, coarse sediments were stored within fans, and fines were transported downstream by sheet flows or sub-surface flows. In most of smaller colluvial fans and debris cones, sediments were delivered by mass movement processes (mainly rockfalls and snowfalls) and did not reach lower margin of landforms. Analysis of historical aerial photographs indicated recent increase in the activity of debris-flow modification of surface morphology of fans. Fans located outside limits of the Little Ice Age (LIA) glaciation are dominated by the secondary processes

  18. Discussion on Plain Stitch Embroidery in Early China Based on New Unearthed Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Li-bing; ZHONG Heng

    2007-01-01

    Plain stitch embroidery of Han Dynasty and before is rarely unearthed. Among the large amount of embroidery excavated from Haiqu ( 海曲 )Han tombs in Rizhao( 日照), Shandoug, an embroidery fragment with plain stitch was found. This is the first plain stitch embroidery with a typical cloudy pattern in Han Dynasty unearthed up to now. And its needlework was very skillful. Combining the two pieces of plain stitch embroidery on wool fabrics found in Wubao( 五堡) tomb at Hami (哈密 ) Xinjiang and Mawangdui ( 马王堆 )Han tombs, we recognized that the application of plain stitch was earlier than scholars considered before. As basic plain stitchwork was poorer in art expression than chain stitchwork, it was less adopted in extravagant silk embroidery. But for ordinary status, plain stitch was more popular to be used in embroidery.

  19. Integrated hydrological modelling of the North China Plain

    DEFF Research Database (Denmark)

    Shu, Yunqiao; Villholth, Karen G.; Jensen, Karsten Høgh;

    2012-01-01

    to and the associated dynamics of the alluvial aquifers based on climatic conditions, land use, soil characteristics, irrigation and coupled unsaturated-saturated zone processes. The model was auto-calibrated for the period 1996–2002 against daily observations of groundwater head from wells distributed across the 7230...... for scenario analysis of the effect of different cropping rotations, irrigation intensity, and other water management options, like the implementation of the South to North Water Transfer (SNWT) project. The model analysis verified that groundwater tables in the region are subject to steep declines (up to 1 m...... solely reverse declining water tables across the region. Combining the SNWT project and implementing region-wide crop and irrigation system changes, including deficit irrigation, wastewater irrigation, and alternating winter fallow, provides a feasible means to stabilize groundwater levels in the area....

  20. BED MORPHOLOGY OF THE KOSI RIVER, GANGETIC PLAINS

    Institute of Scientific and Technical Information of China (English)

    Prabhata K.SWAMEE; Barham PARKASH; Harbhajan SINGH

    2002-01-01

    A mathematical model for simulating morphological changes in space and time of the 124 km long alluvial reach of the Kosi River based on the data in the period 1968-79 is developed. Equations are obtained to describe the changes of streambed parameters such as minimum bed level, river width and maximum river depth. Fourier sine series are used to fit the river cross-sections over the studied reach for different years. The general trend of a stream cross-section can be modeled satisfactorily with the Fourier sine series. Temporal variations in bed level and width of the river have time periods of about 7year and 3.2-4.3 years, respectively, and are controlled by mean annual discharge with a time period of 13.9 years.

  1. Bank accretion and the development of vegetated depositional surfaces along modified alluvial channels

    Science.gov (United States)

    Hupp, C.R.; Simon, A.

    1991-01-01

    This paper describes the recovery of stable bank form and development of vegetated depositional surfaces along the banks of channelized West Tennessee streams. Most perennial streams in West Tennessee were straightened and dredged since the turn of the century. Patterns of fluvial ecological responses to channelization have previously been described by a six-stage model. Dendrogeomorphic (tree-ring) techniques allowed the determination of location, timing, amount, and rate of bank-sediment deposition. Channel cross sections and ecological analyses made at 101 locations along 12 streams, encompassing bends and straight reaches, show that channel and bank processes initially react vertically to channelization through downcutting. A depositional surface forms on banks once bed-degradation and heightened bank mass wasting processes have eased or slowed. The formation of this depositional surface marks the beginning of bank recovery from channelization. Dominating lateral processes, characteristic of stable or natural channels, return during the formation and expansion of the depositional surface, suggesting a relation with thalweg deflection, point-bar development, and meanderloop extension. Characteristic woody riparian vegetation begins to grow as this depositional surface develops and becomes part of the process and form of restabilizing banks. The depositional surface initially forms low on the bank and tends to maintain a slope of about 24??. Mean accretion rates ranges from 5.9 cm/yr on inside bends to 0 cm/yr on most outside bends; straight reaches have a mean-accretion rate of 4.2 cm/yr. The relatively stable, convex upward, depositional surface expands and ultimately attaches to the flood plain. The time required for the recovery process to reach equilibrium averaged about 50 years. Indicative pioneer speccies of woody riparian vegetation include black willow, river birch, silver maple, and boxelder. Stem densities generally decrease with time after and

  2. Analysis and assessment on heavy metal sources in the coastal soils developed from alluvial deposits using multivariate statistical methods.

    Science.gov (United States)

    Li, Jinling; He, Ming; Han, Wei; Gu, Yifan

    2009-05-30

    An investigation on heavy metal sources, i.e., Cu, Zn, Ni, Pb, Cr, and Cd in the coastal soils of Shanghai, China, was conducted using multivariate statistical methods (principal component analysis, clustering analysis, and correlation analysis). All the results of the multivariate analysis showed that: (i) Cu, Ni, Pb, and Cd had anthropogenic sources (e.g., overuse of chemical fertilizers and pesticides, industrial and municipal discharges, animal wastes, sewage irrigation, etc.); (ii) Zn and Cr were associated with parent materials and therefore had natural sources (e.g., the weathering process of parent materials and subsequent pedo-genesis due to the alluvial deposits). The effect of heavy metals in the soils was greatly affected by soil formation, atmospheric deposition, and human activities. These findings provided essential information on the possible sources of heavy metals, which would contribute to the monitoring and assessment process of agricultural soils in worldwide regions.

  3. Drinking Water Quality Criterion - Based site Selection of Aquifer Storage and Recovery Scheme in Chou-Shui River Alluvial Fan

    Science.gov (United States)

    Huang, H. E.; Liang, C. P.; Jang, C. S.; Chen, J. S.

    2015-12-01

    Land subsidence due to groundwater exploitation is an urgent environmental problem in Choushui river alluvial fan in Taiwan. Aquifer storage and recovery (ASR), where excess surface water is injected into subsurface aquifers for later recovery, is one promising strategy for managing surplus water and may overcome water shortages. The performance of an ASR scheme is generally evaluated in terms of recovery efficiency, which is defined as percentage of water injected in to a system in an ASR site that fulfills the targeted water quality criterion. Site selection of an ASR scheme typically faces great challenges, due to the spatial variability of groundwater quality and hydrogeological condition. This study proposes a novel method for the ASR site selection based on drinking quality criterion. Simplified groundwater flow and contaminant transport model spatial distributions of the recovery efficiency with the help of the groundwater quality, hydrological condition, ASR operation. The results of this study may provide government administrator for establishing reliable ASR scheme.

  4. A new methodology for the quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding (MBES)

    Science.gov (United States)

    Best, Jim; Simmons, Stephen; Parsons, Daniel; Oberg, Kevin; Czuba, Jonathan; Malzone, Chris

    2010-01-01

    In order to investigate the interactions between turbulence and suspended sediment transport in natural aqueous environments, we ideally require a technique that allows simultaneous measurement of fluid velocity and sediment concentration for the whole flow field. Here, we report on development of a methodology using the water column acoustic backscatter signal from a multibeam echo sounder to simultaneously quantify flow velocities and sediment concentrations. The application of this new technique is illustrated with reference to flow over the leeside of an alluvial sand dune, which allows, for the first time in a field study, quantitative visualization of large-scale, whole flow field, turbulent coherent flow structures associated with the dune leeside that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows.

  5. A new methodology for the quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding (MBES)

    Science.gov (United States)

    Best, Jim; Simmons, Stephen; Parsons, Daniel; Oberg, Kevin; Czuba, Jonathan; Malzone, Chris

    2010-03-01

    In order to investigate the interactions between turbulence and suspended sediment transport in natural aqueous environments, we ideally require a technique that allows simultaneous measurement of fluid velocity and sediment concentration for the whole flow field. Here, we report on development of a methodology using the water column acoustic backscatter signal from a multibeam echo sounder to simultaneously quantify flow velocities and sediment concentrations. The application of this new technique is illustrated with reference to flow over the leeside of an alluvial sand dune, which allows, for the first time in a field study, quantitative visualization of large-scale, whole flow field, turbulent coherent flow structures associated with the dune leeside that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows.

  6. Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification Ratios from Fast Multipole BEM Simulations

    CERN Document Server

    Fajardo, Kristel C Meza; Chaillat, Stéphanie; Lenti, Luca

    2016-01-01

    In this work, we study seismic wave amplification in alluvial basins having 3D standard geometries through the Fast Multipole Boundary Element Method in the frequency domain. We investigate how much 3D amplification differs from the 1D (horizontal layering) case. Considering incident fields of plane harmonic waves, we examine the relationships between the amplification level and the most relevant physical parameters of the problem (impedance contrast, 3D aspect ratio, vertical and oblique incidence of plane waves). The FMBEM results show that the most important parameters for wave amplification are the impedance contrast and the so-called equivalent shape ratio. Using these two parameters, we derive simple rules to compute the fundamental frequency for various 3D basin shapes and the corresponding 3D/1D amplification factor for 5% damping. Effects on amplification due to 3D basin asymmetry are also studied and incorporated in the derived rules.

  7. Effect of seasonal flooding cycle on litterfall production in alluvial rainforest on the middle Xingu River (Amazon basin, Brazil).

    Science.gov (United States)

    Camargo, M; Giarrizzo, T; Jesus, A J S

    2015-08-01

    The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.

  8. Regional Similarity of Leveed Lava Flows on the Mars Plains

    Science.gov (United States)

    Baloga, Steve M.; Glaze, Lori, S.

    2008-01-01

    The dynamics of lava flow movement are controlled by the fluid interior. Crust, solids, and nondeformable material can only retard the advance or spreading of a lava flow. Figure 1 shows a typical large, channelized lava flow found on the Mars plains. It has been suggested in [I] that such large leveed flows on the Mars plains were emplaced by a balance between the formation and shedding of crust as the flow advances. For the prototypical flow north of Pavonis Mons (Fig. I), such a balance leads to a flow morphology that approximately self-replicates at all locations along the flow path [2,3]. Moreover, most quantitative characteristics of emplacement (e.g., viscosity, volumetric flow rate) of the prototype flow at Pavonis Mons resembled those of large channelized lava flows on Earth. The exception was the relatively long, sustained supply of lava, on the order of a year as opposed to hours or days for terrestrial analogs.

  9. A Wear Geometry Model of Plain Woven Fabric Composites

    Directory of Open Access Journals (Sweden)

    Gu Dapeng

    2014-09-01

    Full Text Available The paper g describes a model meant for analysis of the wear geometry of plain woven fabric composites. The referred model consists of a mathematical description of plain woven fabric based on Peirce’s model coupled with a stratified method for the solution of the wear geometry. The evolutions of the wear area ratio of weft yarn, warp yarn and matrix resin on the worn surface are simulated by MatLab software in combination of warp and weft yarn diameters, warp and weft yarn-to-yarn distances, fabric structure phases (SPs. By comparing theoretical and experimental results from the PTFE/Kevlar fabric wear experiment, it can be concluded that the model can present a trend of the component area ratio variations along with the thickness of fabric, but has a inherently large error in quantitative analysis as an idealized model.

  10. The measurement of plain weft-knitted fabric stiffness

    Science.gov (United States)

    Haji Mohamad, Ayhan; Cassidy, Thomas; Brydon, Alan; Halley, Dave

    2012-05-01

    A new instrument and a test method are presented in this paper that can evaluate the stiffness of plain weft-knitted fabrics. The WIRA Instrumentation Tester can measure torsion data for various flexible fibre assemblies whilst they are being twisted. The torsional properties of two types of fabrics, namely nonwoven and knitted fabrics, were analyzed. Then, comparisons between bending rigidity and torsional rigidity have been conducted using FAST-2, Shirley, Heart Loop and the new WIRA method for the assessment of fabric stiffness. The results show high correlation between bending rigidity and torsional rigidity in assessment of nonwoven fabric stiffness; they also reveal that the WIRA tester and torsional rigidity are more suitable for characterizing the stiffness of plain weft-knitted fabrics than the other test methods.

  11. NONLINEAR MICRO-MECHANICAL MODEL FOR PLAIN WOVEN FABRIC

    Institute of Scientific and Technical Information of China (English)

    ZhangYitong; XieYuxin

    2003-01-01

    The warp yarns and weft yarns of plain woven fabric which, being the principal axes of material of fabric, are orthogonal in the original configuration, but are obliquely crossed in the deformed configuration in general. The orthotropic constitutive model is unsuitable for fabric. In the oblique principal axes system the relations between loaded stress vectors and stress tensor are investigated, the stress fields of micro-weaving structures of fabric due to pure shear are carefully studied and, finally, a nonlinear micro-mechanical model for plain woven fabric is proposed. This model can accurately describe the nonlinear mechanical behavior of fabric observed in experiments. Under the assumption of small deformation and linearity of mechanical properties of fabric the model will degenerate into the existing linear model.

  12. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes

    Science.gov (United States)

    Zhang, Yong; Green, Christopher T.; Tick, Geoffrey R.

    2015-01-01

    This study evaluates the role of the Peclet number as affected by molecular diffusion in transient anomalous transport, which is one of the major knowledge gaps in anomalous transport, by combining Monte Carlo simulations and stochastic model analysis. Two alluvial settings containing either short- or long-connected hydrofacies are generated and used as media for flow and transport modeling. Numerical experiments show that 1) the Peclet number affects both the duration of the power-law segment of tracer breakthrough curves (BTCs) and the transition rate from anomalous to Fickian transport by determining the solute residence time for a given low-permeability layer, 2) mechanical dispersion has a limited contribution to the anomalous characteristics of late-time transport as compared to molecular diffusion due to an almost negligible velocity in floodplain deposits, and 3) the initial source dimensions only enhance the power-law tail of the BTCs at short travel distances. A tempered stable stochastic (TSS) model is then applied to analyze the modeled transport. Applications show that the time-nonlocal parameters in the TSS model relate to the Peclet number, Pe. In particular, the truncation parameter in the TSS model increases nonlinearly with a decrease in Pe due to the decrease of the mean residence time, and the capacity coefficient increases with an increase in molecular diffusion which is probably due to the increase in the number of immobile particles. The above numerical experiments and stochastic analysis therefore reveal that the Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer–aquitard complexes.

  13. Debris flood hazard documentation and mitigation on the Tilcara alluvial fan (Quebrada de Humahuaca, Jujuy province, North-West Argentina)

    Science.gov (United States)

    Marcato, G.; Bossi, G.; Rivelli, F.; Borgatti, L.

    2012-06-01

    For some decades, mass wasting processes such as landslides and debris floods have been threatening villages and transportation routes in the Rio Grande Valley, named Quebrada de Humauhuaca. One of the most significant examples is the urban area of Tilcara, built on a large alluvial fan. In recent years, debris flood phenomena have been triggered in the tributary valley of the Huasamayo Stream and reached the alluvial fan on a decadal basis. In view of proper development of the area, hazard and risk assessment together with risk mitigation strategies are of paramount importance. The need is urgent also because the Quebrada de Humahuaca was recently included in the UNESCO World Cultural Heritage. Therefore, the growing tourism industry may lead to uncontrolled exploitation and urbanization of the valley, with a consequent increase of the vulnerability of the elements exposed to risk. In this context, structural and non structural mitigation measures not only have to be based on the understanding of natural processes, but also have to consider environmental and sociological factors that could hinder the effectiveness of the countermeasure works. The hydrogeological processes are described with reference to present-day hazard and risk conditions. Considering the socio-economic context, some possible interventions are outlined, which encompass budget constraints and local practices. One viable solution would be to build a protecting dam upstream of the fan apex and an artificial channel, in order to divert the floodwaters in a gully that would then convey water and sediments into the Rio Grande, some kilometers downstream of Tilcara. The proposed remedial measures should employ easily available and relatively cheap technologies and local workers, incorporating low environmental and visual impacts issues, in order to ensure both the future conservation of the site and its safe exploitation for inhabitants and tourists.

  14. An expert system supporting decision making process for sustainable groundwater use in main alluvial aquifers in Slovenia

    Science.gov (United States)

    Souvent, Petra; Vižintin, Goran; Celarc, Sašo; Čenčur Curk, Barbara

    2016-04-01

    The expert decision support system for groundwater management in the shallow alluvial aquifers was developed to assist the decision makers to quantify available groundwater for a given alluvial aquifer and provide additional information about quantity of groundwater available for water rights licensing. The system links numerical groundwater flow models with the water permits and concessions databases in a complex decision support system. Six regional stand-alone groundwater models are used in the process of the assessment of groundwater quantitative status as well as for assessing availability of groundwater resources during the period of maximum water consumption and minimum groundwater recharge. Model runs have been realized in a steady state and are calibrated to a medium-low hydrological field conditions, because water quantities for all already granted as well as to-be granted water rights have to be ensured in any time for several years. The major goal of the expert decision support system is therefore to provide control mechanisms in order to verify the water rights licensing for the sustainable use of groundwater resources. The system enables that the water quantity data from water permits and concessions in conjunction with the results of numerical groundwater modeling are used in the managing process of granting new water rights to users in terms of their long-term access to groundwater (sufficient quantity of groundwater) and in relation to the water rights of other users (co-impact of groundwater pumping). Also, groundwater access must be managed in such a way that it does not cause unacceptable local impacts (pumping must not lower the water level for more than 2/3 of water body in the medium-low hydrological conditions).

  15. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Science.gov (United States)

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export and nonproprietary format files This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace aquifer encompasses the unconsolidated terrace deposits and alluvium associated with the North Fork of the Red River and the Red River in the western half of Tillman County. These sediments consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer extends over an area of 285 square miles and is used for irrigation and domestic purposes. Granite and the Hennessey Formation outcrop in northern parts of the aquifer where alluvial deposits are absent. These outcrops were included as part of the aquifer in a thesis that modeled the ground-water flow in the aquifer. Most of the aquifer boundaries and some of the lines in the hydraulic conductivity and recharge data sets were extracted from a published digital surficial geology data set based on a scale of 1:250,000. Most of the lines in the hydraulic conductivity, recharge, and 1969 water-level elevation contour data sets, and one line in the aquifer boundary data set were digitized from a paper map published at a scale of 1:249,695 in a thesis in which the ground-water flow in the aquifer was modeled. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

  16. Debris flood hazard documentation and mitigation on the Tilcara alluvial fan (Quebrada de Humahuaca, Jujuy province, North-West Argentina

    Directory of Open Access Journals (Sweden)

    G. Marcato

    2012-06-01

    Full Text Available For some decades, mass wasting processes such as landslides and debris floods have been threatening villages and transportation routes in the Rio Grande Valley, named Quebrada de Humauhuaca. One of the most significant examples is the urban area of Tilcara, built on a large alluvial fan. In recent years, debris flood phenomena have been triggered in the tributary valley of the Huasamayo Stream and reached the alluvial fan on a decadal basis.

    In view of proper development of the area, hazard and risk assessment together with risk mitigation strategies are of paramount importance. The need is urgent also because the Quebrada de Humahuaca was recently included in the UNESCO World Cultural Heritage. Therefore, the growing tourism industry may lead to uncontrolled exploitation and urbanization of the valley, with a consequent increase of the vulnerability of the elements exposed to risk. In this context, structural and non structural mitigation measures not only have to be based on the understanding of natural processes, but also have to consider environmental and sociological factors that could hinder the effectiveness of the countermeasure works.

    The hydrogeological processes are described with reference to present-day hazard and risk conditions. Considering the socio-economic context, some possible interventions are outlined, which encompass budget constraints and local practices. One viable solution would be to build a protecting dam upstream of the fan apex and an artificial channel, in order to divert the floodwaters in a gully that would then convey water and sediments into the Rio Grande, some kilometers downstream of Tilcara. The proposed remedial measures should employ easily available and relatively cheap technologies and local workers, incorporating low environmental and visual impacts issues, in order to ensure both the future conservation of the site and its safe exploitation for inhabitants and tourists.

  17. Structural Reliability of Plain Bearings for Wave Energy Converter Applications

    Directory of Open Access Journals (Sweden)

    Simon Ambühl

    2016-02-01

    Full Text Available The levelized cost of energy (LCOE from wave energy converters (WECs needs to be decreased in order to be able to become competitive with other renewable electricity sources. Probabilistic reliability methods can be used to optimize the structure of WECs. Optimization is often performed for critical structural components, like welded details, bolts or bearings. This paper considers reliability studies with a focus on plain bearings available from stock for the Wavestar device, which exists at the prototype level. The Wavestar device is a point absorber WEC. The plan is to mount a new power take-off (PTO system consisting of a discrete displacement cylinder (DDC, which will allow different hydraulic cycles to operate at constant pressure levels. This setup increases the conversion efficiency, as well as decouples the electricity production from the pressure variations within the hydraulic cycle when waves are passing. The new PTO system leads to different load characteristics at the floater itself compared to the actual setup where the turbine/generator is directly coupled to the fluctuating hydraulic pressure within the PTO system. This paper calculates the structural reliability of the different available plain bearings planned to be mounted at the new PTO system based on a probabilistic approach, and the paper gives suggestions for fulfilling the minimal target reliability levels. The considered failure mode in this paper is the brittle fatigue failure of plain bearings. The performed sensitivity analysis shows that parameters defining the initial crack size have a big impact on the resulting reliability of the plain bearing.

  18. Costs of Placing Fill in a Flood Plain.

    Science.gov (United States)

    1975-05-01

    Computation 5 Engineering. Enviromental and Legal Aspects of Filling 6 STUDY CONCLUSIONS 8 APPENDIX "Guidelines for Filling Floodplains," Bauer Engineering...Various attempts have been made to estimate an economic value of the ecosystem and from this the economic loss or gain due to its modification. Whether...or not an economic value is estimated, the changes - quantitative and qualitative - should be recognized. An examination of several flood plain

  19. Furrow Dike Water Conservation Practices in the Texas High Plains

    OpenAIRE

    Wistrand, Glen L.

    1984-01-01

    Furrow diking can prevent irrigation and rainfall runoff, conserve energy use, prevent soil loss, amd allow producers to reclaim land otherwise unusable, depending on soil, climate, and crops grown in a given area. Initial investment to use this technique may be recovered within the first season. This study analyzes the effects of diking on water and soil conservation, crop yields, costs, and energy use in farming, using examples of farms in the Texas High Plains area.

  20. Carpal pseudoerosions: a plain X-ray interpretation pitfall

    Energy Technology Data Exchange (ETDEWEB)

    Wawer, Richard [Univ. Catholique de Lille (France). Service d' Imagerie Medicale; Budzik, Jean Francois [Univ. Catholique de Lille (France). Service d' Imagerie Medicale; Univ. Nord de France, Boulogne sur Mer (France). Unite de Recherche EA 4490, Physiopathologie des Maladies Osseuses Inflammatoires; Demondion, Xavier [Univ. Lille 2 (France). Service d' Imagerie Musculosquelettique; CHRU Lille (France). Lab. d' Anatomie; Forzy, Gerard [Univ. Catholique de Lille, Lomme (France). Lab. de Biologie; Cotten, Anne [Univ. Lille 2 (France). Service d' Imagerie Musculosquelettique; Univ. Nord de France, Boulogne sur Mer (France). Unite de Recherche EA 4490, Physiopathologie des Maladies Osseuses Inflammatoires

    2014-10-15

    To examine in detail images of pseudoerosion of the wrist and hand on plain radiographs. The study was conducted with 28 cadaver wrists. During a single imaging session three techniques - plain radiography, tomosynthesis, and computed tomography - were used to visualize the wrist and hand specimens. For each technique, 20 radio-ulno-carpo-metacarpal sites known to present bone erosions in rheumatoid arthritis were analyzed by two radiologists using a standard system to score the cortical bone: normal, pseudoerosion, true erosion, or other pathology. Cohen's concordance analysis was performed to determine inter-observer and intra-observer (for the senior radiologist) agreement by site and by technique. Serial sections of two cadaver specimens were examined to determine the anatomical correlation of the pseudoerosions. On the plain radiographs, the radiologists scored many images as pseudoerosion (7.3 %), particularly in the distal ulnar portion of the capitate, the distal radial portion of the hamate, the proximal ulnar portion of the base of the third metacarpal, the proximal radial portion of the base of the fourth metacarpal, the distal ulnar portion of the hamate, and the proximal portion of the base of the fifth metacarpal. The computed tomography scan revealed that none of these doubtful images corresponded to true erosions. The anatomical correlation study showed that these images could probably be attributed to ligament insertions, thinner lamina, and enhanced cortical bone transparency. Knowledge of the anatomical carpal localizations where pseudoerosions commonly occur is a necessary prerequisite for analysis of plain radiographs performed to diagnose or monitor rheumatoid arthritis. (orig.)

  1. Hydrogeochemical modeling of groundwater chemical environmental evolution in Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    郭永海; 沈照理; 钟佐燊

    1997-01-01

    Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline water with fresh water in middle-eastern area are studied. The water-rock interactions and mass transfer along a ground-water flow path and in mixing processes are calculated. Thus the evolution mechanisms of the groundwater chemical environment are brought to light.

  2. Groundwater quality in the Santa Barbara Coastal Plain, California

    Science.gov (United States)

    Davis, Tracy A.; Belitz, Kenneth

    2016-10-03

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California established the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Santa Barbara Coastal Plain is one of the study units.

  3. San Agustin Plains, New Mexico: Age and paleoenvironmental potential reassessed

    Science.gov (United States)

    Markgraf, Vera; Bradbury, J. Platt; Forester, R. M.; Singh, G.; Sternberg, R. S.

    1984-11-01

    Paleomagnetic analysis of samples from the original 600-m-long core from the San Agustin Plains, New Mexico, showed an unquestionable reversal stratigraphy dating the record back to at least 1.6 my. Analysis of pollen, ostracodes, and algae of a duplicate sample section in the vicinity of the original coring site and spanning the last 18,000 yr B.P. shows a much higher resolution than the earlier results.

  4. METRIC Estimated ET Evaluation on the Semiarid Southern High Plains

    Science.gov (United States)

    Chavez, J. L.; Gowda, P. H.; Colaizzi, P. D.; Evett, S. R.; Howell, T. A.; Copeland, K.

    2007-05-01

    Declining groundwater levels in the Southern High Plains of the United States, and the fact that agriculture in this region uses more than 90% of groundwater withdrawals, combine to increase the demand for efficient agricultural water use. Accurate regional evapotranspiration (ET) maps would provide valuable information on crop water use. In this study, we applied METRIC (Mapping Evapotranspiration at High Resolution using Internalized Calibration), a remote sensing based ET algorithm, and micrometeorological data measured at a grass reference ET weather station maintained by the Texas High Plains Evapotranspiration Network (TXHPET). For this purpose, a Landsat Thematic Mapper image covering a major portion of the Southern High Plains (parts of Texas Panhandle and northeastern New Mexico) was acquired for 23 July 2006 at 11:26 AM CST. Comprehensive ground-truth data were collected to develop a detailed land use map showing major crops grown in the region. Performance of the METRIC model was evaluated using measured ET data on five weighing lysimeters at Bushland, TX [35 Deg. 11' N, 102 Deg. 06' W; 1,170 m elevation MSL] managed by the Conservation and Production Research Laboratory, USDA-ARS. Lysimeter-measured ET rates varied from 2.4 to 7.8 mm/d. Good agreement was found between the remote sensing based ET and measured ET. Comparison of estimated daily mapped ET values with lysimetric measurements had an accuracy within 9% of the measured ET (r2 = 0.89) with a mean square error of 0.9 mm/d. The use of METRIC for advective conditions of the Southern High Plains is promising; however, more evaluation is needed for different agroclimatological conditions.

  5. Groundwater components in the alluvial aquifer of the alpine Rhone River valley, Bois de Finges area, Wallis Canton, Switzerland

    Science.gov (United States)

    Schürch, Marc; Vuataz, François-D.

    2000-09-01

    Source, type, and quantity of various components of groundwater, as well as their spatial and temporal variations were determined by different hydrochemical methods in the alluvial aquifer of the upper Rhone River valley, Bois de Finges, Wallis Canton, Switzerland. The methods used are hydrochemical modeling, stable-isotope analysis, and chemical analysis of surface water and groundwater. Sampling during high- and low-water periods determined the spatial distribution of the water chemistry, whereas monthly sampling over three years provided a basis for understanding seasonal variability. The physico-chemical parameters of the groundwater have spatial and seasonal variations. The groundwater chemical composition of the Rhone alluvial aquifer indicates a mixing of weakly mineralized Rhone River water and SO4-rich water entering from the south side of the valley. Temporal changes in groundwater chemistry and in groundwater levels reflect the seasonal variations of the different contributors to groundwater recharge. The Rhone River recharges the alluvial aquifer only during the summer high-water period. Résumé. Origine, type et quantité de nombreux composants d'eau de l'aquifère alluvial dans la vallée supérieure du Rhône, Bois de Finges, Valais, Suisse, ainsi que leurs variations spatiales et temporelles ont été déterminés par différentes méthodes hydrochimiques. Les méthodes utilisées sont la modélisation hydrochimique, les isotopes stables, ainsi que l'échantillonnage en période de hautes eaux et de basses eaux pour étudier la distribution spatiale de la composition chimique, alors qu'un échantillonnage mensuel pendant trois ans sert à comprendre les processus de la variabilité saisonnière. Les paramètres physico-chimiques des eaux souterraines montrent des variations spatiales et saisonnières. La composition chimique de l'aquifère alluvial du Rhône indique un mélange entre une eau peu minéralisée venant du Rhône et une eau sulfatée s

  6. Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: Bankfull and macrochannels in the Llano River watershed, central Texas, USA

    Science.gov (United States)

    Heitmuller, Franklin T.; Hudson, Paul F.; Asquith, William H.

    2015-03-01

    The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel morphology. Field surveys of channel topography and boundary composition are coupled with sediment analyses, hydraulic computations, flood-frequency analyses, and geographic information system mapping to discern controls on channel geometry (profile, pattern, and shape) and dimensions along the mixed alluvial-bedrock Llano River and key tributaries. Four categories of channel classification in a downstream direction include: (i) uppermost ephemeral reaches, (ii) straight or sinuous gravel-bed channels in Cretaceous carbonate sedimentary zones, (iii) straight or sinuous gravel-bed or bedrock channels in Paleozoic sedimentary zones, and (iv) straight, braided, or multithread mixed alluvial-bedrock channels with sandy beds in Precambrian igneous and metamorphic zones. Principal findings include: (i) a nearly linear channel profile attributed to resistant bedrock incision checkpoints; (ii) statistically significant correlations of both alluvial sinuosity and valley confinement to relatively high f (mean depth) hydraulic geometry values; (iii) relatively high b (width) hydraulic geometry values in partly confined settings with sinuous channels upstream from a prominent incision checkpoint; (iv) different functional flow categories including frequently occurring events (excess of 200 watts per square meter (W/m2); and (vi) downstream convergence of hydraulic geometry exponents for bankfull and macrochannels, explained by co-increases of flood magnitude and noncohesive sandy sediments that collectively minimize development of alluvial bankfull indicators. Collectively, these findings indicate

  7. Applying a Model of Curvature-Driven Bend Migration Developed for Alluvial Rivers to a Gravel-Bedded River With Reaches of Exposed Bedrock

    Science.gov (United States)

    Narinesingh, P.; Pizzuto, J. E.

    2009-12-01

    The South River, Virginia, a sinuous, gravel-bedded river influenced by frequent bedrock exposures, appears at first glance to be meandering. However, when its planform statistics are compared to a freely meandering river (the Teklanika River, Alaska), systematic differences become apparent. Bends of the South River have shorter lengths, longer radii of curvatures, a distinctive meander wavelength spectrum, and a lower fractal dimension of D = 1.11 than those of the Teklanika River. Sixty five percent of the length of South River in the study area consists of sections with exposed bedrock (either on the bed or the banks) and islands. Alluvial floodplains of varying lengths are scattered between sections of bedrock and islands, accounting for the remaining 35% of the study reach. In these areas, the South River displays sinuosity values that may be as high as 2.5. Within the alluvial reaches, aerial photographs from 1937 and 2005 document significant channel migration. Driven by the need to quantify the flux of mercury-contaminated sediments entering the river through bank erosion, we applied the bend migration model of Johannesson and Parker (1989). The model, when schematized for hydraulics of the alluvial sections of the South River and calibrated to the total area of erosion mapped from aerial photographs, correctly predicts 45% of the observed locations of erosion as mapped from the aerial photographs and observed in the field. The total area of erosion computed using the predicted near-bank excess velocity is within 14% of that mapped. According to a non-parametric Kruskal-Wallis test, the predicted areas of erosion along the river are not significantly different from those defined by the historical aerial photographs (P >= 0.05, two tailed test). These results suggest that curvature dependent hydraulic models for alluvial rivers may provide useful predictions of total erosion of alluvium on mixed bedrock/alluvial rivers like the South River. However, improved

  8. Quaternary alluvial fans of Ciudad Juárez, Chihuahua, northern México: OSL ages and implications for climatic history of the region

    Science.gov (United States)

    Zúñiga de León, David; Kershaw, Stephen; Mahan, Shannon

    2016-01-01

    Alluvial fans formed from sediments derived from erosion of the Juárez Mountains in northernmost México have a significant flood impact on the Ciudad Juárez, which is built on the fan system. The northern part of Ciudad Juárez is the most active; further south, older parts of the fan, upon which the rest of the city is built, were largely eroded by natural processes prior to human habitation and subsequently modified only recently by human construction. Three aeolian sand samples, collected from the uppermost (youngest) parts of the fan system in the city area, in places where human intervention has not disturbed the sediment, and constrain the latest dates of fan building. Depositional ages of the Quaternary alluvial fans were measured using Optically Stimulated Luminescence (OSL) on aeolian sands that have inter-fingered with alluvial fan material. These dates are: a) sample P1, 31 ka; b) sample P2, 41 ka; c) sample P3, 74 ka, between Oxygen Isotope Stages (OIS) 3 to 5. They demonstrate that fan development, in the area now occupied by the city, terminated in the Late Pleistocene, immediately after what we interpret to have been an extended period of erosion without further deposition, lasting from the Late Pleistocene to Holocene. The three dates broadly correspond to global glacial periods, implying that the cool, dry periods may reflect periods of aeolian transport in northern México in between phases that were wetter to form the alluvial fans. Alluvial fan margins inter-finger with fluvial terrace sediments derived from the Río Bravo, indicating an additional component of fan dissection by Río Bravo lateral erosion, presumed to be active during earlier times than our OSL ages, but these are not yet dated. Further dating is required to ascertain the controls on the fan and fluvial system.

  9. Acute neuropathic joint in diabetic foot: Plain radiographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Dae Young; Kang, Heung Sik; Sim, Jung Suk; Yoon, Yong Kyu; Kim, Chu Wan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1994-05-15

    To determine the plain film findings of acute neuropathic joint in diabetic foot. Acute neuropathic joint in diabetic foot was considered when fragmentation of the articular ends of bone and subluxation of the affected joint developed within eight weeks after clinical onset of diabetic gangrene. Eight toes of six diabetics were satisfactory to our criteria. We analyzed plain radiographic findings of the affected joint and soft tissue, interval changes in followed-up radiographs, and deformities after healing. The time interval between clinical onset of gangrene and bone destruction ranges from 2 weeks to 4 weeks(mean 2.6 weeks). Plane radiographs showed fragmentation of the articular ends, subluxation, and soft tissue swelling of the metatarsophalangeal joint or interphalangeal joint. The significant feature of these patients was rapid progression of the lesions. Clinically, all patients had diabetic gangrene in affected toes, however, there was no evidence of osteomyelitis in our series. Amputation was done in 2 cases, and lesions in 3 of the remaining 4 cases were repaired spontaneously with regression of gangrene, leaving radiological residua such as pointed-end, tapered-end, and ball and socket deformity. Rapid disorganisation of the joint with associated evidence of soft tissue gangrene in plain radiograph is believed to be valuable for the diagnosis of diabetic osteoarthropathy.

  10. The High Plains Aquifer, USA: Groundwater development and sustainability

    Science.gov (United States)

    Dennehy, K.F.; Litke, D.W.; McMahon, P.B.

    2002-01-01

    The High Plains Aquifer, located in the United States, is one of the largest freshwater aquifers in the world and is threatened by continued decline in water levels and deteriorating water quality. Understanding the physical and cultural features of this area is essential to assessing the factors that affect this groundwater resource. About 27% of the irrigated land in the United States overlies this aquifer, which yields about 30% of the nation's groundwater used for irrigation of crops including wheat, corn, sorghum, cotton and alfalfa. In addition, the aquifer provides drinking water to 82% of the 2.3 million people who live within the aquifer boundary. The High Plains Aquifer has been significantly impacted by human activities. Groundwater withdrawals from the aquifer exceed recharge in many areas, resulting in substantial declines in groundwater level. Residents once believed that the aquifer was an unlimited resource of high-quality water, but they now face the prospect that much of the water may be gone in the near future. Also, agricultural chemicals are affecting the groundwater quality. Increasing concentrations of nitrate and salinity can first impair the use of the water for public supply and then affect its suitability for irrigation. A variety of technical and institutional measures are currently being planned and implemented across the aquifer area in an attempt to sustain this groundwater resource for future generations. However, because groundwater withdrawals remain high and water quality impairments are becoming more commonplace, the sustainability of the High Plains Aquifer is uncertain.

  11. Options of sustainable groundwater development in Beijing Plain, China

    Science.gov (United States)

    Zhou, Yangxiao; Wang, Liya; Liu, Jiurong; Li, Wenpeng; Zheng, Yuejun

    Overexploitation of groundwater resources has supported rapid social and economical developments in Beijing City in last 30 years. The newly constructed emergency well fields have saved Beijing from a critical water crisis caused by a long drought spell of eight consecutive years from 1999 to 2006. But this unsustainable development has resulted in serious consequences: discharges to rivers ceased, large number of pumping wells went dry, and land subsidence caused destruction of underground infrastructure. The completion of the middle route of South to North water transfer project to transfer water from Yangtze river to Beijing City by 2010 provides opportunity to reverse the trend of groundwater depletion and to achieve a long-term sustainable development of groundwater resources in Beijing Plain. Four options of groundwater development in Beijing Plain were formulated and assessed with a regional transient groundwater flow model. The business as usual scenario was used as a reference for the comparative analysis and indicates fast depletion of groundwater resources. The reduction of abstraction scenario has immediate and fast recovery of groundwater levels, especially at the cone of depression. The scenario of artificially enhanced groundwater recharge would replenish groundwater resources and maintain the capacity of present water supply well fields. The combined scenario of the reduction of abstraction and the increase of recharge could bring the aquifer systems into a new equilibrium state in 50 years. A hydrological sustainability of groundwater resources development could then be achieved in Beijing Plain.

  12. Systematic assessment of constipation on plain abdominal radiographs in children

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, Maurice van den; Graafmans, Doortje [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Nievelstein, Rutger; Beek, Erik [Wilhelmina Children' s Hospital, Department of Paediatric Radiology, Utrecht (Netherlands)

    2006-03-15

    Constipation in childhood is common and its clinical assessment is often difficult. Plain abdominal radiography is simple and used to quantify constipation. Three scoring systems, those of Barr et al., Leech et al. and Blethyn et al., have been developed to quantify fecal loading on the abdominal radiograph. In order to determine which method is the most useful in clinical practice, we assessed the reproducibility of the three scoring systems. Plain abdominal radiographs from 40 clinically constipated children were retrospectively reviewed by two paediatric radiologists on two separate occasions. The radiographs were scored according to three different systems developed by Barr et al., Leech et al., Blethyn et al. Intraobserver variability and interobserver reproducibility were determined for each system. Kappa coefficients were calculated as indicators of inter- and intraobserver agreement for categorical outcome variables. The Leech score showed the highest reproducibility: the intraobserver agreement was high for both observers ({kappa} values of 0.88 and 1.00, respectively, P<0.05). Furthermore, the interobserver agreement was also high: {kappa} 0.91 in the first round and 0.84 in the second. The Leech score proved to be a highly reproducible tool for assessment of childhood constipation and is of value in clinical practice for systematic assessment of constipation on plain abdominal radiographs in children. (orig.)

  13. Hydrologic Controls On Methylmercury Availability In Coastal Plain Rivers

    Science.gov (United States)

    Bradley, P. M.; Brigham, M. E.; Burns, D. A.; Button, D. T.; Lutz, M. A.; Marvin-DiPasquale, M. C.; Riva-Murray, K.; Journey, C.

    2011-12-01

    Methylmercury (MeHg) in streams is often attributed to methylation in up-gradient wetland areas, with episodic flood events maximizing wetland-stream hydrologic connectivity and dominating MeHg supply to the stream habitat. A number of studies have demonstrated that Coastal Plain streams in the southeastern United States are particularly vulnerable to high MeHg bioaccumulation and have attributed this vulnerability to wetland abundance and strong hydrologic connectivity between wetland areas and adjacent stream aquatic habitat. Because characteristically coarse-grained Coastal Plain sediments favor vertical infiltration with little surface runoff, flood events attributable to Coastal Plain precipitation are driven by rising groundwater, promoting efficient transport of MeHg from wetland/floodplain source areas to the stream habitat and increasing in-stream availability. Several observations at McTier Creek, South Carolina, however, suggest that good hydrologic connectivity and efficient MeHg transport in Coastal Plain systems are not limited to flood conditions. Close correspondence between stream and shallow-groundwater water levels at McTier indicate good hydrologic connectivity exists prior to flood conditions. Dissolved MeHg concentrations do not increase under flood conditions. Thus, we assessed the flux of water and dissolved mercury (Hg) species (FMeHg and total Hg (FTHg)) from surface water and groundwater sources in a short reach at McTier Creek during separate events in April and July 2009, to determine the importance of shallow groundwater Hg transport from floodplain areas to the stream under non-flood conditions. Mass balance assessments indicated that, under non-flood conditions, the primary supply of water, FMeHg, and FTHg within the reach (excluding upstream surface-water influx) was groundwater discharge, rather than tributary transport from wetlands, in-stream MeHg production, or atmospheric deposition. The results indicate efficient transport of

  14. The migration, dissolution, and fate of chlorinated solvents in the urbanized alluvial valleys of the southwestern USA

    Science.gov (United States)

    Jackson, R. E.

    The migration, dissolution, and subsequent fate of spilled chlorinated solvents in the urban alluvial valleys of the southwestern U.S. appear to be governed by a unique set of hydrogeologic and geochemical processes occurring within terrigeneous clastic depositional systems. The alluvial and lacustrine fill of the basins, the trapping of solvents in fine-grained sediments beneath the urbanized valley centers, the oxic conditions typical of the deeper alluvium, and the contaminant-transport patterns produced by large-scale basin pumping combine to produce long aqueous-phase plumes derived from the dissolution of trapped chlorinated solvents. Although of limited aqueous solubility, these dense solvents are sufficiently mobile and soluble in the southwestern alluvial valleys to have produced aqueous plumes that have migrated several kilo