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Sample records for adjacent alluvial aquifer

  1. Hydrogeologic characteristics of the alluvial aquifer and adjacent deposits of the Fountain Creek valley, El Paso County, Colorado

    USGS Publications Warehouse

    Radell, Mary Jo; Lewis, Michael E.; Watts, Kenneth R.

    1994-01-01

    The alluvial aquifer in Fountain Creek Valley between Colorado Springs and Widefield is the source for several public-supply systems. Because of the importance of this aquifer, defining aquifer boundaries, areas where underflow occurs, and where Fountain Creek is hydraulically connected to the aquifer will greatly add to the understanding of the alluvial aquifer and management of the public- supply systems. Bedrock altitude, water-table altitude for October 1991, saturated thickness for October 1991, selected hydrogeologic sections in the alluvial aquifer and adjacent deposits of the Fountain Creek Valley, and estimated underflow rates are mapped or tabulated for the area between Colorado Springs and Widefield, Colorado. Results from test drilling indicate that the bedrock surface is highly irregular and that several ridges and buried channels exist in the study area. These features affect the direction of ground-water flow on a local scale. In places, a shale ridge prevents exchange of water between Fountain Creek and the aquifer. Generally, ground water flowed toward Fountain Creek during the study (June 1991 to September 1992) in response to relatively high hydraulic heads in the aquifer and the steep gradients on the boundaries of the study area. Water levels, which were measured monthly, varied little during the study, except in areas near pumping wells or adjacent to Fountain Creek. Hydraulic-conductivity values, estimated from 30 bail tests in wells completed in the alluvial aquifer, were used to determine underflow across the saturated boundaries of the alluvial aquifer. Estimated hydraulic-conductivity values range from 1 to about 1,300 feet per day; the larger values occur in the buried channel of the alluvial aquifer and the smaller values occur near the boundaries of the saturated alluvium. Estimated underflow into the study area exceeded underflow out of the study area by about 10 times. Gain-loss investigations along Fountain Creek indicated that the

  2. Effects of fluctuating river-pool stages on ground-water levels in the adjacent alluvial aquifer in the lower Arkansas River, Arkansas

    USGS Publications Warehouse

    Freiwald, D.A.; Grosz, G.D.

    1988-01-01

    The U.S. Geological Survey conducted a study in cooperation with the U.S. Army Corps of Engineers to determine the effect of fluctuating the lower Arkansas River. A network of 41 wells was used to delineate 4 cross sections adjacent to river pools 2 and 5 of the McClellan-Kerr Arkansas River Navigation System to examine groundwater levels at various distances from the river. The hydraulic gradient of water levels in the alluvial aquifer along these cross sections indicates that the river is losing water to the adjacent aquifer. The effect on groundwater levels in the alluvial aquifer caused by pool-stage fluctuations was most pronounced at distances less than about 2 miles from the Arkansas River. At distances greater than about 2 miles, the changes in groundwater levels probably were the result of water levels rising in the aquifer since the heavy summer irrigation withdrawals have ceased. An equation useful for estimating the distribution of head change an aquifer in response to river-pool-stage changes, was applied to the study area to estimate the effect of a 1-foot rise in pool stage on water levels in the adjacent alluvial aquifer after equilibrium conditions have been established. The theoretical head change (rise) in the aquifer was estimated to range from 1-foot at the Arkansas River to 0.57 foot at a distance of 5 miles away from the river. (USGS)

  3. Directional scales of heterogeneity in alluvial fan aquifers

    SciTech Connect

    Neton, M.J.; Dorsch, J.; Young, S.C.; Olson, C.D. . Dept. of Geological Sciences Tennessee Valley Authority Engineering Lab., Norris, TN )

    1992-01-01

    Abrupt lateral and vertical permeability changes of up to 12 orders of magnitude are common in alluvial fan aquifers due to depositional heterogeneity. This abrupt heterogeneity is problematic, particularly in construction of a continuous hydraulic conductivity field from point measurements. Site characterization is improved through use of a scale-and-directionally-related model of fan heterogeneities. A directional classification of alluvial fan aquifer heterogeneities is proposed. The three directional scales of heterogeneity in alluvial fan aquifers are: (1) within-fan, (2) between-fan (strike-parallel), and (3) cross-fan (strike-perpendicular). Within-fan heterogeneity ranges from very small-scale intergrain relationships which control the nature of pores, to larger scale permeability trends between fan apex and toe, and includes abrupt lateral and vertical facies relationships. Between-fan heterogeneities are of a larger-scale and include differences between adjacent (non)coalescent fans along a basin-margin fault due primarily to changes in lithology between adjacent upland source basins. These differences produce different (a) grain and pore fluid compositions, (b) lithologic facies and proportions, and (c) down-fan fining trends, between adjacent fans. Cross-fan heterogeneities extend from source to basin. Fan deposits are in abrupt contact upgradient with low permeability, basin-margin source rock. Downgradient, fan deposits are in gradational to abrupt contact with time-equivalent, generally lower permeability deposits of lake, desert, longitudinal braided and meandering river, volcanic, and shallow marine environments. Throughout basin history these environments may abruptly cover the fan with low permeability horizons.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Groundwater-flow assessment of the Mississippi River Valley alluvial aquifer of northeastern Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.

    2010-01-01

    The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. Pumping of groundwater from the alluvial aquifer for agriculture started in the early 1900s in the Grand Prairie area for the irrigation of rice and soybeans. From 1965 to 2005, water use in the alluvial aquifer increased 655 percent. In 2005, 6,242 million gallons per day of water were pumped from the aquifer, primarily for irrigation and fish farming. Water-level declines in the alluvial aquifer were documented as early as 1927. Long-term water-level measurements in the alluvial aquifer show an average annual decline of 1 foot per year in some areas. In this report, the utility of the updated 2009 MODFLOW groundwater-flow model of the alluvial aquifer in northeastern Arkansas was extended by performing groundwater-flow assessments of the alluvial aquifer at specific areas of interest using a variety of methods. One such area is along the western side of Crowleys Ridge, which includes western parts of Clay, Greene, Craighead, Poinsett, Cross, St. Francis, and Lee Counties. This area was designated as the Cache Critical Groundwater Area by the Arkansas Natural Resources Commission in 2009 for the alluvial and Sparta/Memphis aquifers, because of the rate of change in groundwater levels and groundwater levels have dropped below half the original saturated thickness of the alluvial aquifer.

  6. Spatio-temporal dynamics of nitrogen in river-alluvial aquifer systems affected by diffuse pollution from agricultural sources: Implications for the implementation of the Nitrates Directive

    NASA Astrophysics Data System (ADS)

    Arauzo, M.; Valladolid, M.; Martínez-Bastida, J. J.

    2011-12-01

    SummaryReducing nitrate pollution from diffuse agricultural sources is the major environmental challenge in the two adjacent catchments of the Oja-Tirón and Zamaca rivers (La Rioja and Castilla y León, northern Spain). For this reason, part of their territory was designated a Nitrate Vulnerable Zone (NVZ) according to the Nitrates Directive. The Oja Alluvial Aquifer, the Tirón Alluvial Aquifer and their associated rivers are particularly vulnerable to nitrogen pollution due to the shallow water table, the high permeability of alluvial deposits, interconnections between the alluvial aquifers and surface waters and pressures from agriculture. To this end, nine sampling campaigns, organised on a semi-annual basis and focused on the rivers and alluvial aquifers of the two catchments, were carried out from April 2005 to April 2009. The main objectives of the study were: (1) to investigate the chemical forms of nitrogen in river-alluvial aquifer systems of the Oja-Tirón and Zamaca catchments, (2) to improve our understanding of the spatio-temporal patterns of nitrogen distribution in the alluvial aquifers and associated rivers by integrating hydrochemical data and hydrogeological and environmental parameters, (3) to estimate the amount of nitrogen exported from the rivers and alluvial aquifers to the River Ebro, and (4) to evaluate the suitability of the current method of designating NVZs in the area. High groundwater flow velocities in the upper alluvial zones favoured the advective transport of nitrate and generated a dilution effect. In these areas, inter-annual variations in nitrate concentrations were observed related to precipitation and N-input from agriculture. However, low flow velocities favoured processes of accumulation in the lower alluvial zones. Our results demonstrated that the entire alluvial surface was highly vulnerable, according to dynamics of the nitrogen in the river-alluvial aquifer systems being studied. The amount of nitrogen exported from

  7. Hydrogeology and simulation of ground-water flow in the alluvial aquifer at Louisville, Kentucky

    USGS Publications Warehouse

    Lyverse, M.A.; Starn, J.J.; Unthank, M.D.

    1996-01-01

    The alluvial aquifer at Louisville, Ky., lies in a valley eroded by glacial meltwater that was later partly filled with outwash sand and gravel deposits. The aquifer is primarily unconfined, and the direction of flow is from the adjacent limestone and shale valley wall toward the Ohio River and major pumping centers. Pumpage and water-level data indicate that the alluvial aquifer was in a steady-state condition in November 1962 and again in November 1983. Between these two dates, water-level data indicate a general rise in the water table. A two-dimensional finite-element ground-water-flow model of the alluvial aquifer was calibrated for both the steady-state and the transient-state period of 1962-83. The year 1962 represented a period in time when pumping was nearly three times that in 1983. The simulated steady-state water budget for 1962 indicated that of the total recharge to the aquifer of 5.19 million feet per day, 37.2 percent was flow from the river to pumped wells, 28.3 percent was recharge from rainfall, 19.7 percent was flow across the eastern valley wall, and 14.8 percent was upward flow from the bedrock. Discharge from the aquifer was to wells (68.9 percent) and to the Ohio River (31.1 percent). The simulated steady-state water budget for 1983 indicated that of the total recharge to the aquifer of 4.11 million feet per day, 42.6 percent was recharge from rainfall, 18.2 percent was flow across the eastern valley wall, 17.8 percent was flow from the river to pumped wells, 15.6 percent was upward flow from the bedrock, and 5.8 percent was flow from septic systems. The transient simulation resulted in an acceptable match between measured and simulated hydrographs. This gave additional confidence to the model calibration, choice of boundary conditions, and published values of specific yield. Both steady-state and transient-state models demonstrated that the main source of water needed to meet increased pumping requirements was induced flow from the Ohio

  8. Conjunctive-use optimization model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.; Clark, Brian R.; Reed, Thomas B.

    2003-01-01

    The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. Because of the heavy demands placed on the aquifer, several large cones of depression over 100 feet deep have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. A ground-water flow model of the alluvial aquifer was previously developed for an area covering 14,104 square miles, extending northeast from the Arkansas River into the northeast corner of Arkansas and parts of southeastern Missouri. The flow model showed that continued ground-water withdrawals at rates commensurate with those of 1997 could not be sustained indefinitely without causing water levels to decline below half the original saturated thickness of the aquifer. To develop estimates of withdrawal rates that could be sustained in compliance with the constraints of critical ground-water area designation, conjunctive-use optimization modeling was applied to the flow model of the alluvial aquifer in northeastern Arkansas. Ground-water withdrawal rates form the basis for estimates of sustainable yield from the alluvial aquifer and from rivers specified within the alluvial aquifer model. A management problem was formulated as one of maximizing the sustainable yield from all ground-water and surface-water withdrawal cells within limits imposed by plausible withdrawal rates, and within specified constraints involving hydraulic head and streamflow. Steady-state flow conditions were selected because the maximized withdrawals are intended to represent sustainable yield of the system (a rate that can be maintained indefinitely). Within the optimization model, 11 rivers are specified. Surface-water diversion rates that occurred in 2000 were subtracted from specified overland flow at the appropriate river cells. Included in these diversions were the

  9. Conjunctive-use optimization model of the Mississippi River Valley alluvial aquifer of Southeastern Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.; Clark, Brian R.; Stanton, Gregory P.

    2003-01-01

    The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. Because of the heavy demands placed on the aquifer, several large cones of depression have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. A ground-water flow model of the alluvial aquifer was previously developed for an area covering 3,826 square miles, extending south from the Arkansas River into the southeastern corner of Arkansas, parts of northeastern Louisiana, and western Mississippi. The flow-model results indicated that continued ground-water withdrawals at rates commensurate with those of 1997 could not be sustained indefinitely without causing water levels to decline below half the original saturated thickness of the aquifer. Conjunctive-use optimization modeling was applied to the flow model of the alluvial aquifer to develop withdrawal rates that could be sustained relative to the constraints of critical ground-water area designation. These withdrawal rates form the basis for estimates of sustainable yield from the alluvial aquifer and from rivers specified within the alluvial aquifer model. A management problem was formulated as one of maximizing the sustainable yield from all ground-water and surface-water withdrawal cells within limits imposed by plausible withdrawal rates, and within specified constraints involving hydraulic head and streamflow. Steady-state conditions were selected because the maximized withdrawals are intended to represent sustainable yield of the system (a rate that can be maintained indefinitely).One point along the Arkansas River and one point along Bayou Bartholomew were specified for obtaining surface-water sustainable-yield estimates within the optimization model. Streamflow constraints were specified at two river cells based on average 7-day low flows

  10. Hydrogeology and simulation of ground-water flow in the Ohio River alluvial aquifer near Carrollton, Kentucky

    USGS Publications Warehouse

    Unthank, Michael D.

    1999-01-01

    The alluvial aquifer near Carrollton, Kentucky, lies in a valley eroded by glacial meltwater that was later part filled with outwash sand and gravel deposits. The aquifer is unconfined, and ground water flows from the adjacent bedrock-valley wall toward the Ohio River and ground-water withdrawal wells. Ground-water-level and Ohio River stage data indicate the alluvial aquifer was at or near steady-state condition in November 1995. A two-dimensional, steady-state ground-water-flow model was developed to estimate the hydraulic properties, the rate of recharge, and the contributing areas to discharge boundaries for the Ohio River alluvial aquifer at Carrollton and the surrounding area. Results from previous investigations, available hydrogeologic data, and observations of water levels from area ground-water wells were compiled to conceptualize the ground-water-flow system and construct the numerical model. Ground water enters the modeled area by induced infiltration from the Ohio River and smaller streams, flow from the bedrock-valley wall, and infiltration of precipitation. Ground water exits the modeled area primarily through withdrawal wells and flow to the Ohio River. A sensitivity analysis of the model indicates that it is most sensitive to changes in the stage of the Ohio River and conductance values for the riverbed material. A particle-tracking simulation was used to delineate recharge and discharge boundaries of the flow system and contributing areas for withdrawal wells, and to estimate time of travel through the flow system.

  11. Alluvial aquifers in the Mzingwane catchment: Their distribution, properties, current usage and potential expansion

    NASA Astrophysics Data System (ADS)

    Moyce, William; Mangeya, Pride; Owen, Richard; Love, David

    The Mzingwane River is a sand filled channel, with extensive alluvial aquifers distributed along its banks and bed in the lower catchment. LandSat TM imagery was used to identify alluvial deposits for potential groundwater resources for irrigation development. On the false colour composite band 3, band 4 and band 5 (FCC 345) the alluvial deposits stand out as white and dense actively growing vegetation stands out as green making it possible to mark out the lateral extent of the saturated alluvial plain deposits using the riverine fringe and vegetation . The alluvial aquifers form ribbon shaped aquifers extending along the channel and reaching over 20 km in length in some localities and are enhanced at lithological boundaries. These alluvial aquifers extend laterally outside the active channel, and individual alluvial aquifers have been measured with area ranging from 45 ha to 723 ha in the channels and 75 ha to 2196 ha on the plains. The alluvial aquifers are more pronounced in the Lower Mzingwane, where the slopes are gentler and allow for more sediment accumulation. Estimated water resources potential ranges between 175,000 m 3 and 5,430,000 m 3 in the channels and between 80,000 m 3 and 6,920,000 m 3 in the plains. Such a water resource potential can support irrigation ranging from 18 ha to 543 ha for channels alluvial aquifers and 8 ha to 692 ha for plain alluvial aquifers. Currently, some of these aquifers are being used to provide water for domestic use, livestock watering and dip tanks, commercial irrigation and market gardening. The water quality of the aquifers in general is fairly good due to regular recharge and flushing out of the aquifers by annual river flows and floodwater. Water salinity was found to increase significantly in the end of the dry season, and this effect was more pronounced in water abstracted from wells on the alluvial plains. During drought years, recharge is expected to be less and if the drought is extended water levels in the

  12. INFILTRATION OF ATRAZINE AND METABOLOTES FROM A STREAM TO AN ALLUVIAL AQUIFER

    EPA Science Inventory

    The infiltration of atrazine, deethylatrazine, and deisopropylatrazine from Walnut Creek, a tributary stream, to the alluvial valley aquifer along the South Skunk River in central Iowa occurred where the stream transects the river's flood plain. A preliminary estimate indicated t...

  13. Southern California Alluvial Basins Regional Aquifer-Systems analysis; a bibliography

    USGS Publications Warehouse

    Moyle, W.R.; Martin, Peter; Schluter, R.C.; Woolfenden, L.R.; Downing, Karen; Elliott, A.L.; Maltby, D.E.

    1986-01-01

    A bibliography for the Southern California Alluvial Basins Regional Aquifer-Systems Analysis includes references for about 3,500 publications related to the geohydrology of the 75,000 sq-mi region, which encompasses all of southern California except the Central Valley, the Channel Islands and the Pacific Ocean floor off southern California, and parts of adjacent states and Mexico. The report indexes the publications in six geographic categories and induces a list of sources of publications. Because of the large number of references in the bibliography, a system was developed for computer storage and retrieval. References can be retrieved by geographic location, author, or geohydrologic discipline and subject. The computer system allows for updating and addition of references. (USGS)

  14. Modeling of groundwater level fluctuations using dendrochronology in alluvial aquifers

    NASA Astrophysics Data System (ADS)

    Gholami, V.; Chau, K. W.; Fadaee, F.; Torkaman, J.; Ghaffari, A.

    2015-10-01

    Groundwater is the most important water resource in semi-arid and arid regions such as Iran. It is necessary to study groundwater level fluctuations to manage disasters (such as droughts) and water resources. Dendrochronology, which uses tree-rings to reconstruct past events such as hydrologic and climatologic events, can be used to evaluate groundwater level fluctuations. In this study, groundwater level fluctuations are simulated using dendrochronology (tree-rings) and an artificial neural network (ANN) for the period from 1912 to 2013. The present study was undertaken using the Quercus Castaneifolia species, which is present in an alluvial aquifer of the Caspian southern coasts, Iran. A multilayer percepetron (MLP) network was adopted for the ANN. Tree-ring diameter and precipitation were the input parameters for the study, and groundwater levels were the outputs. After the training process, the model was validated. The validated network and tree-rings were used to simulate groundwater level fluctuations during the past century. The results showed that an integration of dendrochronology and an ANN renders a high degree of accuracy and efficiency in the simulation of groundwater levels. The simulated groundwater levels by dendrochronology can be used for drought evaluation, drought period prediction and water resources management.

  15. Alluvial and bedrock aquifers of the Denver Basin; eastern Colorado's dual ground-water resource

    USGS Publications Warehouse

    Robson, Stanley G.

    1989-01-01

    Large volumes of ground water are contained in alluvial and bedrock aquifers in the semiarid Denver basin of eastern Colorado. The bedrock aquifer, for example, contains 1.2 times as much water as Lake Erie of the Great Lakes, yet it supplies only about 9 percent of the ground water used in the basin. Although this seems to indicate underutilization of this valuable water supply, this is not necessarily the case, for many factors other than the volume of water in the aquifer affect the use of the aquifer. Such factors as climatic conditions, precipitation runoff, geology and water-yielding character of the aquifers, water-level conditions, volume of recharge and discharge, legal and economic constraints, and water-quality conditions can ultimately affect the decision to use ground water. Knowledge of the function and interaction of the various parts of this hydrologic system is important to the proper management and use of the ground-water resources of the region. The semiarid climatic conditions on the Colorado plains produce flash floods of short duration and large peak-flow rates. However, snowmelt runoff from the Rocky Mountains produces the largest volumes of water and is typically of longer duration with smaller peak-flow rates. The alluvial aquifer is recharged easily from both types of runoff and readily stores and transmits the water because it consists of relatively thin deposits of gravel, sand, and clay located in the valleys of principal streams. The bedrock aquifer is recharged less easily because of its greater thickness (as much as 3,000 feet) and prevalent layers of shale which retard the downward movement of water in the formations. Although the bedrock aquifer contains more than 50 times as much water in storage as the alluvial aquifer, it does not store and transmit water as readily as the alluvial aquifer. For example, about 91 percent of the water pumped from wells is obtained from the alluvial aquifer, yet water-level declines generally have

  16. How subaerial salt extrusions influence water quality in adjacent aquifers

    NASA Astrophysics Data System (ADS)

    Mehdizadeh, Razieh; Zarei, Mehdi; Raeisi, Ezzat

    2015-12-01

    Brines supplied from salt extrusions cause significant groundwater salinization in arid and semi-arid regions where salt rock is exposed to dissolution by episodic rainfalls. Here we focus on 62 of the 122 diapirs of Hormuz salt emergent in the southern Iran. To consider managing the degradation effect that salt extrusions have on the quality of adjoining aquifers, it is first necessary to understand how they influence adjacent water resources. We evaluate here the impacts that these diapirs have on adjacent aquifers based on investigating their geomorphologies, geologies, hydrologies and hydrogeologies. The results indicate that 28/62 (45%) of our sample of salt diapirs have no significant impact on the quality of groundwater in adjoining aquifers (namely Type N), while the remaining 34/62 (55%) degrade nearby groundwater quality. We offer simple conceptual models that account for how brines flowing from each of these types of salt extrusions contaminate adjacent aquifers. We identify three main mechanisms that lead to contamination: surface impact (Type A), subsurface intrusion (Type B) and indirect infiltration (Type C). A combination of all these mechanisms degrades the water quality in nearby aquifers in 19/62 (31%) of the salt diapirs studied. Having characterized the mechanism(s) by which each diapir affects the adjacent aquifer, we suggest a few possible remediation strategies to be considered. For instance, engineering the surface runoff of diapirs Types A and C into nearby evaporation basins would improve groundwater quality.

  17. Reduced-complexity probabilistic reconstruction of alluvial aquifer stratigraphy, and application to sedimentary fans in northwestern India

    NASA Astrophysics Data System (ADS)

    van Dijk, Wout M.; Densmore, Alexander L.; Sinha, Rajiv; Singh, Ajit; Voller, Vaughan R.

    2016-10-01

    Generating a realistic model of subsurface stratigraphy that fits data from multiple well locations is a well-established problem in the field of aquifer characterisation. This is particularly critical for the alluvial fan-hosted aquifers in northwestern India, as they have some of the highest rates of groundwater extraction in the world and spatially limited subsurface observations. The objective of this study is to develop a reduced-complexity model that generates probabilistic estimates of aquifer body occurrence within a sedimentary fan, based loosely on the northwestern Indian aquifer system. We propose a parsimonious, inverse-weighted random walk model that reconstructs potential channel belt pathways within a discrete depth range or slice by (i) connecting known aquifer locations with the fan apex, (ii) filling adjacent cells with non-aquifer material based on estimated channel-body dimensions, and (iii) random filling of the remaining cells until the model fraction of aquifer material is comparable to the bulk aquifer fraction observed from well data. Once filled, individual depth slices can be stacked to produce a three-dimensional representation of aquifer-body geometry, allowing informed inference and testable predictions about the configuration of aquifer units in the subsurface. A receiver operating characteristic (ROC) curve shows that the model performs better than fully random filling, both in matching the locations of aquifer material in the subsurface and in reconstructing the geometry of relict channel bodies preserved on the fan surface. The model differs from purely statistical-empirical approaches by incorporating some geomorphic knowledge of fluvial channel belt geometry within the fan system. In contrast to a fully process-based approach, the model is computationally fast and is easily refined as new subsurface data become available.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. The hydrogeology of the Condamine River Alluvial Aquifer, Australia: a critical assessment

    NASA Astrophysics Data System (ADS)

    Dafny, Elad; Silburn, D. Mark

    2014-05-01

    The Condamine plain is an important agricultural zone in Australia with prominent irrigated cotton and grain crops. About one third of the irrigation water is pumped from the shallow alluvial aquifer, causing gross aquifer depletion over time. Over the last few decades, various hydrological, hydrochemical, and geological aspects of this aquifer and the overlying floodplain (including soil properties) have been investigated and used to construct the conceptual understanding and numerical models for management of this resource. Yet, the water balance of the aquifer is still far from resolved, and the geological contact between the alluvial sediments and underlying bedrock is yet to be categorically defined, to mention two major uncertainties. This report collates up-to-date knowledge of different disciplines, critically evaluates the accepted hydrogeological conventions, highlights key knowledge gaps, and suggests strategies for future research. Among recommendations are (1) development of numerical flow and solute transport models for the natural (i.e. pre-developed) period, (2) analysis of groundwater for isotopic composition and presence of pesticides, CFCs and PPCPs, and (3) use of stochastic approaches to characterize the hydraulic properties of the alluvial sediments. These and other proposed measures are relevant also to other alluvial aquifers which suffer from similar fundamental uncertainties.

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

    USGS Publications Warehouse

    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.

  2. Tributary stream infiltration as a source of herbicides in an alluvial aquifer

    USGS Publications Warehouse

    Burkart, M.R.; Simpkins, W.W.; Squillace, P.J.; Helmke, M.

    1999-01-01

    Where Walnut Creek flows across the South Skunk River alluvial aquifer, it provides a potential source of herbicides and herbicide metabolites. This straightened reach of the creek loses water and dissolved contaminants to the alluvial aquifer through a layer of fine-grained flood plain deposits. Estimates of potential flux of chemicals were based on measurements taken during baseflow in April 1994 before herbicides were applied to the watershed and in June 1994 after chemical application and when stream discharge included runoff and tile-drainage water. Hydraulic head measurements between the creek and flood plain deposits and between the creek and aquifer confirmed the potential for downward groundwater flow during both sampling periods. Hydraulic conductivity estimates from slug tests were used to calculate an average linear groundwater velocity of 0.5 m d-1 in the fine- grained flood plain deposits. At this velocity, contaminants could be advectively transported to the aquifer within 6 d. The potential for atrazine (2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine) flux to the aquifer from the creek was estimated to be between 60 and 3000 ??g d-1 m-2. This rate is one to three orders of magnitude greater than the estimated flux via leaching beneath a typical field. If the process of vertical stream leakage occurs in many hydrologic settings, it may constitute a substantial source of herbicides to shallow alluvial aquifers in many areas of the Midwest.

  3. Clay Mineralogy of Soils and Sediments from an Alluvial Aquifer, Rifle, Colorado

    NASA Astrophysics Data System (ADS)

    Elliott, W. C.; Zaunbrecher, L. K.; Lim, D.; Pickering, R. A.; Williams, K. H.; Long, P. E.; Qafoku, N. P.

    2014-12-01

    Alluvial aquifers along the Colorado River corridor in central to western Colorado contain legacy contamination including U, V, As and Se. These alluvial aquifers host important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface that are both significant on their own, but also influence contaminant behavior. Mineral phases likely active in the sequestration of metal contaminants are chlorite, smectite-vermiculite, illite, and smectite. These minerals are also important biogeofacies markers. The Colorado alluvial sediments include lenses of silt and clay that are commonly more reduced than coarser grained materials. The clay minerals that make up the alluvial aquifer sediments include these mineral phases important for metal sequestration (chlorite, smectite, illite), as well as kaolinite and quartz. More specifically, the clay mineralogy of soils derived from these sediments at Rifle are composed of the same suite of minerals found in the alluvial sediments plus a vermiculite-smectite intergrade. The vermiculite-smectite intergrade is a weathering product of illite. The presence of illite and chlorite in both the sediments and the soils at Rifle reflect a mineralogically immature character of the source rocks. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate, indicative of mixed provence of immature (chlorite, smectite, illite) and mature (kaolinite) minerals relative to their source areas.

  4. Assessing transmissivity from specific capacity in an alluvial aquifer in the middle Venetian plain (NE Italy).

    PubMed

    Fabbri, Paolo; Piccinini, Leonardo

    2013-01-01

    Defining aquifer permeability distribution accurately over large areas is often debated in hydrogeology. The operational efforts to calculate hydraulic conductivity with classical aquifer tests are significant; however, accurate knowledge of permeability areal distribution is fundamental both from a hydrogeological and a modeling standpoint. This paper presents an empirical relationship between the transmissivity (T) and the specific capacity (SC) values obtained from experimental aquifer and well tests. All experimental values were obtained from 50 mm wells in middle Venetian plain artesian gravel aquifers. Many other authors have presented empirical relationships between T and SC, but most are related to fissured/karst aquifers, and only a few concern alluvial porous aquifers. Analysis of the T vs. SC relationship standardized residuals shows that a linear relationship produces statistically significant normal residuals compared with an exponential relationship.

  5. NATURAL ARSENIC CONTAMINATION OF HOLOCENE ALLUVIAL AQUIFERS BY LINKED TECTONIC, WEATHERING, AND MICROBIAL PROCESSES

    EPA Science Inventory

    Linked tectonic, geochemical, and biologic processes lead to natural arsenic contamination of groundwater in Holocene alluvial aquifers, which are the main threat to human health around the world. These groundwaters are commonly found a long distance from their ultimate source of...

  6. Infiltration of atrazine and metabolites from a stream to an alluvial aquifer

    USGS Publications Warehouse

    Squillace, P.J.; Burkart, M.R.; Simpkins, W.W.

    1997-01-01

    The infiltration of atrazine, deethylatrazine, and deisopropylatrozine from Walnut Creek, a tributary stream, to the alluvial valley aquifer along the South Skunk River in central Iowa occurred where the stream transects the river's flood plain. A preliminary estimate indicated that the infiltration was significant and warrants further investigation. Infiltration was estimated by measuring the loss of stream discharge in Walnut Creek and the concentrations of atrazine and its metabolites deethylatrazine and deisopropylatrazine, in ground water 1 m beneath the streambed. Infiltration was estimated before application of agrichemicals to the fields during a dry period on April 7, 1994, and after application of agrichemicals during a period of small runoff on June 8, 1994. On April 7, the flux of atrazine, deethylatrazine, and deisopropylatrazine from Walnut Creek into the alluvial valley aquifer ranged from less than 10 to 60 (??g/d)/m2, whereas on June 8 an increased flux ranged from 270 to 3060 (??g/d)/m2. By way of comparison, the calculated fluxes of atrazine beneath Walnut Creek, for these two dates, were two to five orders of magnitude greater than an estimated flux of atrazine to ground water caused by leaching from a field on a per-unit-area basis. Furthermore, the unit-area flux rates of water from Walnut Creek to the alluvial valley aquifer were about three orders of magnitude greater than estimated recharge to the alluvial aquifer from precipitation. The large flux of chemicals from Walnut Creek to the alluvial valley aquifer was due in part to the conductive streambed and rather fast ground water velocities; average vertical hydraulic conductivity through the streambed was calculated as 35 and 90 m/d for the two sampling dates, and estimated ground water velocities ranged from 1 to 5 m/d.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Hydrogeology and simulation of flow between the alluvial and bedrock aquifers in the upper Black Squirrel Creek basin, El Paso County, Colorado

    USGS Publications Warehouse

    Watts, K.R.

    1995-01-01

    Anticipated increases in pumping from the bedrock aquifers in El Paso County potentially could affect the direction and rate of flow between the alluvial and bedrock aquifers and lower water levels in the overlying alluvial aquifer. The alluvial aquifer underlies about 90 square miles in the upper Black Squirrel Creek Basin of eastern El Paso County. The alluvial aquifer consists of unconsolidated alluvial deposits that unconformably overlie siltstones, sandstones, and conglomerate (bedrock aquifers) and claystone, shale, and coal (bedrock confining units) of the Denver Basin. The bedrock aquifers (Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers) are separated by confining units (upper and lower Denver and the Laramie confining units) and overlie a relatively thick and impermeable Pierre confining unit. The Pierre confining unit is assumed to be a no-flow boundary at the base of the alluvial/ bedrock aquifer system. During 1949-90, substantial water-level declines, as large as 50 feet, in the alluvial aquifer resulted from withdrawals from the alluvial aquifer for irrigation and municipal supplies. Average recharge to the alluvial aquifer from infiltration of precipitation and surface water was an estimated 11.97 cubic feet per second and from the underlying bedrock aquifers was an estimated 0.87 cubic foot per second. Water-level data from eight bedrock observation wells and eight nearby alluvial wells indicate that, locally, the alluvial and bedrock aquifers probably are hydraulically connected and that the alluvial aquifer in the upper Black Squirrel Creek Basin receives recharge from the Denver and Arapahoe aquifers but-locally recharges the Laramie-Fox Hills aquifer. Subsurface-temperature profiles were evaluated as a means of estimating specific discharge across the bedrock surface (the base of the alluvial aquifer). However, assumptions of the analytical method were not met by field conditions and, thus, analyses of subsurface-temperature profiles

  9. Water-level maps of the alluvial aquifer, northwestern Mississippi, September 1981

    USGS Publications Warehouse

    Darden, Daphne

    1982-01-01

    Water levels were measured in 427 wells in the Mississippi River valley alluvial aquifer in northwestern Mississippi during the period September 15-28, 1981. Water levels in the alluvial sands and gravel were generally lower than water levels in September 1980 and larger depressions in the surface of the ground-water body were detected in the Sunflower-Leflore County area and in Humphreys County. These depressions are attributed to heavy pumping for irrigation and to less-than normal rainfall. Other smaller depressions are attributed to local heavy pumping. (USGS)

  10. Characterization and simulation of flow in the lower Arkansas River alluvial aquifer, south-central Kansas

    USGS Publications Warehouse

    Jian, Xiaodong; Combs, Lanna J.; Hansen, Cristi V.

    2004-01-01

    Large parts of the lower Arkansas, Ninnescah, and Walnut River Basins in south-central Kansasan area that includes Wichita, the largest city in Kansasare experiencing rapid population growth and, consequently, increasing demands on surface- and ground-water resources in addition to agricultural irrigation in the area. The quantity and quality of water available in the lower Arkansas, Ninnescah, and Walnut River Basins in Butler, Cowley, Sedgwick, and Sumner Counties are crucial as population and water use continue to increase in the region. A steady-state model was constructed to simulate flow in the Arkansas River alluvial aquifer between Wichita and Arkansas City. Calibration was achieved using March 2001 measured water levels and streamflow gain using long-term (19402001) streamflow records. Average recharge about 5 inches per year; average aquifer hydraulic conductivity was about 500 feet per day; well pumpage (average of reported 19982001 use) was 56 cubic feet per second; and net flow from the alluvial aquifer to streams in the modeled area was computed by hydrograph separation to be 157 cubic feet per second. Nine hypothetical simulations were conducted with ground-water pumpage varying from zero to double authorized pumpage (206 cubic feet per second). Net remaining aquifer thickness declined for the largest simulated pumpage increases in comparison to 19982001 average pumping, as did flow from the aquifer to the Arkansas River. Simulated aquifer thickness decreases were more pronounced in areas where pumpage is currently (2004) greatest.

  11. Geostatistical modeling of a portion of the alluvial aquifer of Mexico City

    NASA Astrophysics Data System (ADS)

    Morales-Casique, E.; Medina-Ortega, P.; Escolero-Fuentes, O.; Hernandez Espriu, A.

    2012-12-01

    Mexico City is one of the largest cities in the world and the pressure exerted on water resources generates problems such as intensive groundwater exploitation, subsidence and groundwater pollution. Most of the main aquifer under exploitation underlies lacustrine sediments and it is composed of a highly heterogeneous mixture of alluvial deposits and volcanic rocks. Lithological records from 113 production water wells are analyzed using indicator geostatistics. The different lithological categories are grouped into four hydrofacies, where a hydrofacies is a set of lithological categories which have similar hydraulic properties. An exponential variogram model was fitted to each hydrofacies by minimizing cross validation errors. The data is then kriged to obtain the three-dimensional distribution of each hydrofacies within the alluvial aquifer of Mexico City.

  12. Impact of sedimentary heterogenities and sinuosity on river -aquifer exchanges in a meandering alluvial plain.

    NASA Astrophysics Data System (ADS)

    Rivière, A.; Maillot, M.; Weill, P.; Goblet, P.; Ors, F.

    2015-12-01

    A coupled sedimentary and hydrogeological model is used to quantify the impact of sedimentary heterogeneities and sinuosity on groundwater fluxes in an alluvial plain deposited by a meandering fluvial system. A 3D heterogeneous alluvial plain model is built with the stochastic/process-based model FLUMY, that simulates the evolution and the sedimentary processes of a meandering channel and its associated deposits. The resulting sedimentary blocks are translated in terms of hydrodynamic parameters (hydrofacies) and used in the 3D transient water transport model METIS. The simulated domain is 10 m-thick and at a pluri-kilometric horizontal scale, allowing considering several meanders. A head gradient between the upstream and downstream limits is imposed. The river is considered as a constant-head boundary that decreases linearly along the channel centerline. A zero-flux condition is prescribed on the other boundaries. Several cases are studied, including different degrees of sinuosity and different configurations of sediment heterogeneity: (i) a homogeneous sandy aquifer (ii) single mud-filled oxbow lake in a sandy porous media, (iii) several mud-filled oxbow lakes in a sandy porous media, and (iv) "fully" heterogeneous alluvial plain including fine-grained overbank deposits, sandy point bars, mudplugs and sandy crevasse plays. We quantify the exchange rates and directions between the river and the aquifer along the channel centerline, the piezometric evolution and the water residence time in the heterogeneous alluvial plain. This original method can improve our understanding of the functioning of alluvial corridors and evaluate the relevance of taking into account the structural heterogeneity of alluvial plains in larger regional hydrogeological models.

  13. High-resolution characterization of chemical heterogeneity in an alluvial aquifer

    USGS Publications Warehouse

    Schulmeister, M.K.; Healey, J.M.; Butler, J.J.; McCall, G.W.; Birk, S.

    2002-01-01

    The high-resolution capabilities of direct push technology were exploited to develop new insights into the hydrochemistry at the margin of an alluvial aquifer. Hydrostratigraphic controls on groundwater flow and contaminant loading were revealed through the combined use of direct push electrical conductivity (EC) logging and geochemical profiling. Vertical and lateral variations in groundwater chemistry were consistent with sedimentary features indicated by EC logs, and were supported by a conceptual model of recharge along the flood plain margin.

  14. High-resolution characterization of chemical heterogeneity in an alluvial aquifer

    USGS Publications Warehouse

    Schulmeister, M.K.; Healey, J.M.; McCall, G.W.; Birk, S.; Butler, J.J.

    2002-01-01

    The high-resolution capabilities of direct-push technology were exploited to develop new insights into the hydrochemistry at the margin of an alluvial aquifer. Hydrostratigraphic controls on groundwater flow and contaminant loading were revealed through the combined use of direct-push electrical conductivity (EC) logging and geochemical profiling. Vertical and lateral variations in groundwater chemistry were consistent with sedimentary features indicated by EC logs, and supported a conceptual model of recharge along the floodplain margin.

  15. Geohydrology and simulation of ground-water flow for the Ohio River alluvial aquifer near Owensboro, northwestern Kentucky

    USGS Publications Warehouse

    Unthank, M.D.

    1997-01-01

    The Ohio River alluvial aquifer is the primary source of drinking water for the residents of Owensboro and Daviess County and adjacent counties in Kentucky. The aquifer consists of sand and gravel deposits that partly fill a bedrock-valley system consisting of shales of Pennsylvanian age. The valley is a result of dissection by the Ohio River during the Pleistocene epoch. The sand and gravel deposits in the bedrock valley are glacial-outwash deposits of Illinoian and Wisconsin age. The thickness of the alluvium ranges from just a few feet near the bedrock-valley walls to nearly 150 feet in the Bon Harbor Hills area west of Owensboro. Estimates of transmissivity of the alluvium near the Ohio River are in excess of 50,000 gallons per day per foot. A two-dimensional, steady-state ground-water-flow model was developed to estimate the hydraulic properties, the rate of recharge, and the contributing areas to discharge boundaries for the Ohio River alluvial aquifer near Owensboro. Results from previous studies, available geohydrologic data, and observations of water levels from area ground-water wells were compiled to conceptualize the ground-water-flow system and construct the numerical model. Ground water enters the modeled area primarily by infiltration from precipitation and river leakage towards nearby wells and exits the modeled area primarily by withdrawal wells, flow through the valley across model boundaries, and discharge to the Ohio River. A sensitivity analysis of the model indicates the model is most sensitive to changes in horizontal hydraulic conductivity, especially near the Ohio River boundary. Particle tracking was used to compute the contributing areas to discharge boundaries. Contributing areas for withdrawal wells at Owensboro Municipal Utilities extended south and east toward the valley walls and model boundaries and toward the Ohio River, where most of the water withdrawn by the wells is from induced flow from the river.

  16. Nitrogen cycling within an alluvial aquifer during groundwater fluctuations

    NASA Astrophysics Data System (ADS)

    Bouskill, N.; Conrad, M. E.; Bill, M.; Brodie, E.; Forbes, M. S.; Casciotti, K. L.; Williams, K. H.

    2015-12-01

    Subsurface terrestrial-aquatic interfaces are hotspots of biogeochemical cycling of terrestrially derived organic matter and nutrients. However, pathways of nitrogen (N) loss within subsurface aquifers are poorly understood. Here we take an experimental and mechanistic modeling approach to gauge the contribution of different microbial functional groups to the transformation and loss of N in an unconfined aquifer at Rifle, Colorado. During 2014 we measured nitrate (NO3), ammonia, gaseous nitrous oxide (N2O) and the corresponding isotopic composition of NO3 and N2O. Coincident with an annual Spring/ Summer excursion in groundwater elevation, we observed a rapid decline in NO3 concentrations at three discrete depths (2, 2.5 and 3 m) within the aquifer. Isotopic measurements (i.e., δ18O and δ15N) of NO3 suggest an immediate onset of biological N loss at 2 m, but not at 3 m where the isotopic composition demonstrated dilution of NO3 concentration prior to the onset of biological N loss. This implies that the groundwater becomes increasingly anoxic as it rises within the capillary fringe. We observed the highest rates of N2O production concomitant with the largest enrichment of the δ18ONO3 and δ15NNO3 isotopes. A mechanistic microbial model representing the diverse physiology of nitrifiers, aerobic and anaerobic (denitrifying) heterotrophs and anammox bacteria indicates that the bulk of N2O production and N loss is attributable to denitrifying heterotrophs. However, this relationship is dependent on the coupling between aerobic and anaerobic microbial guilds at the oxic-anoxic interface. Modeling results suggest anammox plays a more prominent role in N loss under conditions where the organic matter input is low and rapidly drawn down by aerobic heterotrophs prior to the rise of the water table. We discuss our modeling results in light of recent molecular microbiology work at this site, but also with respect to implications for N loss across terrestrial

  17. Groundwater geochemistry and microbial community structure in the aquifer transition from volcanic to alluvial areas.

    PubMed

    Amalfitano, S; Del Bon, A; Zoppini, A; Ghergo, S; Fazi, S; Parrone, D; Casella, P; Stano, F; Preziosi, E

    2014-11-15

    Groundwaters may act as sinks or sources of organic and inorganic solutes, depending on the relative magnitude of biochemical mobilizing processes and groundwater-surface water exchanges. The objective of this study was to link the lithological and hydrogeological gradients to the aquatic microbial community structure in the transition from aquifer recharge (volcanic formations) to discharge areas (alluvial deposits). A field-scale analysis was performed along a water table aquifer in which volcanic products decreased in thickness and areal extension, while alluvial deposits became increasingly important. We measured the main groundwater physical parameters and the concentrations of major and trace elements. In addition, the microbial community structure was assessed by estimating the occurrence of total coliforms and Escherichia coli, the prokaryotic abundance, the cytometric and phylogenetic community composition. The overall biogeochemical asset differed along the aquifer flow path. The concentration of total and live prokaryotic cells significantly increased in alluvial waters, together with the percentages of Beta- and Delta-Proteobacteria. The microbial propagation over a theoretical groundwater travel time allowed for the identification of microbial groups shifting significantly in the transition between the two different hydrogeochemical facies. The microbial community structure was intimately associated with geochemical changes, thus it should be further considered in view of a better understanding of groundwater ecology and sustainable management strategies.

  18. Geohydrologic units and water-level conditions in the Terrace alluvial aquifer and Paluxy Aquifer, May 1993 and February 1994, near Air Force Plant 4, Fort Worth area, Texas

    USGS Publications Warehouse

    Rivers, Glen A.; Baker, Ernest T.; Coplin, L.S.

    1996-01-01

    The terrace alluvial aquifer underlying Air Force Plant 4 and the adjacent Naval Air Station (formerly Carswell Air Force Base) in the Fort Worth area, Texas, is contaminated locally with organic and metal compounds. Residents south and west of Air Force Plant 4 and the Naval Air Station are concerned that contaminants might enter the underlying Paluxy aquifer, which provides water to the city of White Settlement, south of Air Force Plant 4, and to residents west of Air Force Plant 4. The U.S. Environmental Protection Agency has qualified Air Force Plant 4 for Superfund cleanup. The pertinent geologic units include -A~rom oldest to youngest the Glen Rose, Paluxy, and Walnut Formations, Goodland Limestone, and terrace alluvial deposits. Except for the Glen Rose Formation, all units crop out at or near Air Force Plant 4 and the Naval Air Station. The terrace alluvial deposits, which nearly everywhere form the land surface, range from 0 to about 60 feet thick. These deposits comprise a mostly unconsolidated mixture of gravel, sand, silt, and clay. Mudstone and sandstone of the Paluxy Formation crop out north, west, and southwest of Lake Worth and total between about 130 and about 175 feet thick. The terrace alluvial deposits and the Paluxy Formation comprise the terrace alluvial aquifer and the Paluxy aquifer, respectively. These aquifers are separated by the Goodland-Walnut confining unit, composed of the Goodland Limestone and (or) Walnut Formation. Below the Paluxy aquifer, the Glen Rose Formation forms the Glen Rose confining unit. Water-level measurements during May 1993 and February 1994 from wells in the terrace alluvial aquifer indicate that, regionally, ground water flows toward the east-southeast beneath Air Force Plant 4 and the Naval Air Station. Locally, water appears to flow outward from ground-water mounds maintained by the localized infiltration of precipitation and reportedly by leaking water pipes and sanitary and (or) storm sewer lines beneath the

  19. Validity of flowmeter data in heterogeneous alluvial aquifers

    NASA Astrophysics Data System (ADS)

    Bianchi, Marco

    2017-04-01

    Numerical simulations are performed to evaluate the impact of medium-scale sedimentary architecture and small-scale heterogeneity on the validity of the borehole flowmeter test, a widely used method for measuring hydraulic conductivity (K) at the scale required for detailed groundwater flow and solute transport simulations. Reference data from synthetic K fields representing the range of structures and small-scale heterogeneity typically observed in alluvial systems are compared with estimated values from numerical simulations of flowmeter tests. Systematic errors inherent in the flowmeter K estimates are significant when the reference K field structure deviates from the hypothetical perfectly stratified conceptual model at the basis of the interpretation method of flowmeter tests. Because of these errors, the true variability of the K field is underestimated and the distributions of the reference K data and log-transformed spatial increments are also misconstrued. The presented numerical analysis shows that the validity of flowmeter based K data depends on measureable parameters defining the architecture of the hydrofacies, the conductivity contrasts between the hydrofacies and the sub-facies-scale K variability. A preliminary geological characterization is therefore essential for evaluating the optimal approach for accurate K field characterization.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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 2.54 MJ/m3/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

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

    PubMed

    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

  2. Alluvial aquifer of the Cache and St. Francis River basins, northeastern Arkansas

    USGS Publications Warehouse

    Broom, Matthew E.; Lyford, Forest P.

    1981-01-01

    The alluvial aquifer underlies about 9,000 square miles of the study area. Well yields from the aquifer commonly are from 1,000 to 2,000 gallons per minute. Flow toward the main area of pumping stress is eastward from the Cache River and westward from the St. Francis River. The Memphis aquifer acts as a conduit through Crowleys Ridge for induced flow from the St. Francis River basin to the Cache River basn. Water use from the alluvial aquifer since the early 1900 's has been mostly for rice irrigation. Total pumpage for rice in 1978 was about 1,650 ,000 acre-feet, of which about 88 percent was pumped from the aquifer west of Crowleys Ridge. Water levels in wells west of the ridge in parts of Poinsett, Cross, and Craighead Counties in 1978 were 75 feet below land surface and declining about 2 feet per year. Digital-model analysis indicated that at the end of 1978 water was being removed from aquifer storage at the rate of 540,000 acre-feet per year, and streamflow, mostly from the Cache River and Bayou DeView, was being captured at the rate of 430,000 acre-feet per year. Projecting the 1978 pumping rate of 1,460,000 acre-feet per year, the pumping rate would have to be reduced by about 110,000 acre-feet per year by 1990 to sustain sufficient aquifer saturation for water needs through the year 2000 in all parts of Poinsett, Craighead, and Cross Counties west of Crowleys Ridge. (USGS)

  3. The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona

    USGS Publications Warehouse

    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.

  4. Hydrogeology and hydrochemistry of a shallow alluvial aquifer, western Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al-Shaibani, Abdulaziz M.

    2008-02-01

    A hydrogeological and hydrochemical study was conducted on a shallow alluvial aquifer, Wadi Wajj, in western Saudi Arabia to assess the influence of protection measures on groundwater quality. The hydrochemistry was assessed up-gradient and down-gradient from potential contamination sources in the main city in dry and wet seasons prior to and after the installation of major drainage and wastewater facilities. Wadi Wajj is an unconfined aquifer where water is stored and transmitted through fractured and weathered bedrock and the overlying alluvial sediments. Natural recharge to the aquifer is about 5% of rainfall-runoff. Hydrochemistry of the aquifer shows temporal and seasonal changes as influenced by protection measures and rainfall runoff. Both groundwater and runoff showed similar chemical signature, which is mostly of chloride-sulfate-bicarbonate and sodium-calcium type. Groundwater downstream of the city, though of poorer quality than upstream, showed significant improvement after the installation of a concrete runoff tunnel and a wastewater treatment plant. Concentrations of many of the groundwater quality indicators (e.g., TDS, coliform bacteria, and nitrate) exceed US Environmental Protection Agency drinking-water standards. Heavy metal content is, however, within allowable limits by local and international standards. The chemical analyses also suggest the strong influence of stream runoff and sewage water on the groundwater quality.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Summary of available hydrogeologic data for the northeast portion of the alluvial aquifer at Louisville, Kentucky

    USGS Publications Warehouse

    Unthank, Michael D.; Nelson, Hugh L.

    2006-01-01

    The hydrogeologic characteristics of the unconsolidated glacial outwash sand and gravel deposits that compose the northeast portion of the alluvial aquifer at Louisville, Kentucky, indicate a prolific water-bearing formation with approximately 7 billion gallons of ground-water storage and an estimated sustainable yield of over 280 million gallons per day. This abundance of ground water and the need to properly develop and manage this resource has prompted many past investigations (since 1956), which have produced reports, maps, and data files covering a variety of topics relative to the movement, availability, and use of ground water in this area. These data have been compiled into a single report to assist in future development and use of the ground-water resources. Available ground-water data for the alluvial aquifer at Louisville, Kentucky, from Beargrass Creek to Harrods Creek, were compiled from the U.S. Geological Survey National Water Information System and the Kentucky Groundwater Data Repository. Data contained in these databases include ground-water well-construction details and historical ground-water levels, drillers' logs, and water-quality information. Additional data and information were gathered from project files at the U.S. Geological Survey--Kentucky Water Science Center and files at the Louisville Water Company. Information contained in these files included data from area pumping tests describing aquifer characteristics and ground-water flow. Data describing current conditions of the ground-water system in the northeast portion of the alluvial aquifer also are included. Ground-water levels from a network of observation wells show recent trends in the flow system, and information from the Kentucky Division of Water-Groundwater Branch lists current permitted ground-water withdrawals in the area.

  7. Preliminary assessment of water quality in the alluvial aquifer of the Puerco River basin, Northeastern Arizona

    USGS Publications Warehouse

    Webb, R.H.; Rink, G.R.; Radtke, D.B.

    1987-01-01

    The quality of groundwater in the alluvial aquifer of the Puerco River basin, northeastern Arizona, was evaluated in order to assess potential contamination from uranium mining and milling operations in New Mexico. A total of 14 wells and 1 spring were sampled to determine if a contaminant plume of radionuclides or trace elements is present. The water is characterized by high dissolved solids with a median of 698 mg/l and high concentrations of alkalinity, sodium, and sulfate. Except for iron, manganese, and strontium, the concentrations of trace elements generally are below the applicable EPA and State of Arizona maximum contaminant levels. Gross alpha activity has a median of 27 picocuries/l and ranges from 4 to 42 picocuries/l. Uranium, which accounts for most of the gross alpha activity, has a median concentration of 19 micrograms/l and ranges from 1 to 38 micrograms/l. Twenty percent to 84% of the gross alpha activity was derived from other undetermined radionuclides. Other radionuclides, including radium-226 and radium-228, generally are not present in activities > 5 picocuries/l in the water. Statistical analysis of the water quality data suggest that no contaminant plume can be defined on the basis of samples from existing wells. The contamination in the alluvial aquifer apparently does not change in the downstream direction along the Puerco River. The geochemistry of radionuclides indicates that most radionuclides from the uranium-decay series are immobile or only slightly mobile, whereas uranium will not precipitate out of solution but may be removed by sorption in the alluvial aquifer. (Author 's abstract)

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Changes in the volume of water in the Mississippi River alluvial aquifer in the Delta, northwestern Mississippi, 1980-94

    USGS Publications Warehouse

    Arthur, J.K.

    1995-01-01

    The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, Office of Land and Water Resources, and the Natural Resources Conservation Service, estimated the volumetric changes of water in the Mississippi River alluvial aquifer in northwestern Mississippi from 1980 through 1994. Volumetric changes of water in the alluvial aquifer were estimated for the entire Delta and for five selected areas within the Delta. The volume of water per square mile in the alluvial aquifer in the Delta changed from 17,886 acre-feet during fall 1980 to 17,719 acre-feet during fall 1994, a decrease in volume per square mile of 167 acre-feet. The minimum volume of water per square mile in the alluvial aquifer in the Delta during 1980-94 was 17,640 acre-feet during fall 1988. Of five selected areas within the Delta, an area near Cleveland in Bolivar County had the greatest change in volume of water in the alluvial aquifer. During fall 1980 this area had 20,790 acre-feet of water per square mile in the aquifer; by fall 1994, the volume had decreased to 19,947 acre-feet of water per square mile. An area located in the vicinity of the Sunflower-Leflore County line has within its boundaries a large cone of depression in the potentiometric surface of the alluvial aquifer. The volume of water per square mile in this area decreased from 17,857 acre-feet during fall 1980 to 17,075 acre-feet during fall 1994.

  10. Planning report for the southwest alluvial basins (east) regional aquifer-system analysis, parts of Colorado, New Mexico, and Texas

    USGS Publications Warehouse

    Wilkins, D.W.; Scott, W.B.; Kaehler, C.A.

    1980-01-01

    The study of the Southwest alluvial basins (east) will involve an analysis of the regional aquifer system in parts of Colorado, New Mexico, and Texas. This area has been divided into 22 basins. The study of the alluvial aquifer-system will be made in the following stages: (1) project planning, (2) literature searches, (3) compiling existing data, (4) data collection, (5) basin modeling, (6) regional aquifer modeling, and (7) reports. The regional aquifer study will be accomplished through studying each of the 22 basins. Data compilation and limited data collection will be part of each basin study. Digital computer models will be made for those basins where data are sufficient. A regional aquifer model will be developed from the basin models. In addition to this report, there will be basin hydrology reports and the final regional report. Included in the final report will be a description of the regional hydrology and geology. (USGS)

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

    USGS Publications Warehouse

    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)

  12. Geohydrology and simulated effects of large ground-water withdrawals on the Mississippi River alluvial aquifer in northwestern Mississippi

    USGS Publications Warehouse

    Sumner, D.M.; Wasson, Billie E.

    1990-01-01

    The 7,000-square-mile Mississippi River alluvial plain in northwestern Mississippi, locally known as the 'Delta,' is underlain by a prolific aquifer that yielded about 1,100 million gallons per day of water to irrigation wells in 1983. About 20 feet of clay underlying the Delta land surface commonly is underlain by about 80 to 180 feet of sand and gravel that forms the Mississippi River alluvial aquifer. This study of the alluvial aquifer was prompted by recent declines of water levels. The study was designed to better define the hydrology of the aquifer and to quantify availability of water from the aquifer. The Mississippi River is in good hydraulic connection with the alluvial aquifer. Generally, smaller streams are less likely to recharge the aquifer than larger streams. Direct vertical recharge to the alluvial aquifer from the 52 inches per year of precipitation is small, especially in the central part of the Delta. A two-dimensional finite-difference computer model of the alluvial aquifer was constructed, calibrated, and verified using water levels observed for five dates from April 1981 to September 1983. The values of some of the calibration-derived parameters are hydraulic conductivity, 400 feet per day; specific yield, 0.30; and infiltration of precipitation to the aquifer, 0.5 inch per year. The model showed that the aquifer had a net loss in storage of about 360 million gallons per day from April 1981 to April 1983. During this period, pumpage was about 1,100 million gallons per day (1,270,000 acre-feet per year), and the net inflows from the sources of recharge were as follows, in million gallons per day: Mississippi River, 390; recharge along the east edge of the Delta, 170; streams within the Delta, 57; areal recharge from infiltration, 180; and oxbow lakes, 24. The effects of several levels of pumpage by wells--0, 670, 1,100, 1,900, and 4,000 million gallons per day--were projected 20 years into the future. In 2003, the 1,100-milliongallon

  13. Groundwater movement, recharge, and perchlorate occurrence in a faulted alluvial aquifer in California (USA)

    USGS Publications Warehouse

    Izbicki, John A.; Teague, Nicholas F.; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.

    2015-01-01

    Perchlorate from military, industrial, and legacy agricultural sources is present within an alluvial aquifer in the Rialto-Colton groundwater subbasin, 80 km east of Los Angeles, California (USA). The area is extensively faulted, with water-level differences exceeding 60 m across parts of the Rialto-Colton Fault separating the Rialto-Colton and Chino groundwater subbasins. Coupled well-bore flow and depth-dependent water-quality data show decreases in well yield and changes in water chemistry and isotopic composition, reflecting changing aquifer properties and groundwater recharge sources with depth. Perchlorate movement through some wells under unpumped conditions from shallower to deeper layers underlying mapped plumes was as high as 13 kg/year. Water-level maps suggest potential groundwater movement across the Rialto-Colton Fault through an overlying perched aquifer. Upward flow through a well in the Chino subbasin near the Rialto-Colton Fault suggests potential groundwater movement across the fault through permeable layers within partly consolidated deposits at depth. Although potentially important locally, movement of groundwater from the Rialto-Colton subbasin has not resulted in widespread occurrence of perchlorate within the Chino subbasin. Nitrate and perchlorate concentrations at the water table, associated with legacy agricultural fertilizer use, may be underestimated by data from long-screened wells that mix water from different depths within the aquifer.

  14. Revisiting a classification scheme for U.S.-Mexico alluvial basin-fill aquifers.

    PubMed

    Hibbs, Barry J; Darling, Bruce K

    2005-01-01

    Intermontane basins in the Trans-Pecos region of westernmost Texas and northern Chihuahua, Mexico, are target areas for disposal of interstate municipal sludge and have been identified as possible disposal sites for low-level radioactive waste. Understanding ground water movement within and between these basins is needed to assess potential contaminant fate and movement. Four associated basin aquifers are evaluated and classified; the Red Light Draw Aquifer, the Northwest Eagle Flat Aquifer, the Southeast Eagle Flat Aquifer, and the El Cuervo Aquifer. Encompassed on all but one side by mountains and local divides, the Red Light Draw Aquifer has the Rio Grande as an outlet for both surface drainage and ground water discharge. The river juxtaposed against its southern edge, the basin is classified as a topographically open, through-flowing basin. The Northwest Eagle Flat Aquifer is classified as a topographically closed and drained basin because surface drainage is to the interior of the basin and ground water discharge occurs by interbasin ground water flow. Mountains and ground water divides encompass this basin aquifer on all sides; yet, depth to ground water in the interior of the basin is commonly >500 feet. Negligible ground water discharge within the basin indicates that ground water discharges from the basin by vertical flow and underflow to a surrounding basin or basins. The most likely mode of discharge is by vertical, cross-formational flow to underlying Permian rocks that are more porous and permeable and subsequent flow along regional flowpaths beneath local ground water divides. The Southeast Eagle Flat Aquifer is classified as a topographically open and drained basin because surface drainage and ground water discharge are to the adjacent Wildhorse Flat area. Opposite the Eagle Flat and Red Light Draw aquifers is the El Cuervo Aquifer of northern Chihuahua, Mexico. The El Cuervo Aquifer has interior drainage to Laguna El Cuervo, which is a phreatic

  15. Modelling the response of an alluvial aquifer to anthropogenic and recharge stresses in the United States Southern Great Plains

    NASA Astrophysics Data System (ADS)

    Zume, Joseph T.; Tarhule, Aondover A.

    2011-08-01

    This paper uses Visual MODFLOW to simulate potential impacts of anthropogenic pumping and recharge variability on an alluvial aquifer in semi-arid northwestern Oklahoma. Groundwater withdrawal from the aquifer is projected to increase by more than 50% (relative to 1990) by the year 2050. In contrast, climate projections indicate declining regional precipitation over the next several decades, creating a potential problem of demand and supply. The following scenarios were simulated: (1) projected groundwater withdrawal, (2) a severe drought, (3) a prolonged wet period, and (4) a human adjustment scenario, which assumes future improvements in water conservation measures. Results indicate that the combined impacts of anthropogenic pumping and droughts would create drawdown of greater than 12 m in the aquifer. Spatially, however, areas of severe drawdown will be localized around large-capacity well clusters. The worst impacts of both pumping and droughts will be on stream-aquifer interaction. For example, the projected aquifer pumpage would lead to a total streamflow loss of 40%, creating losing stream system regionally. Similarly, a severe drought would lead to a total streamflow loss of >80%. A post-audit of the model was also carried out to evaluate model performance. By simulating various stress scenarios on the alluvial aquifer, this study provides important information for evaluating management options for alluvial aquifers.

  16. Geochemistry of ground water in alluvial basins of Arizona and adjacent parts of Nevada, New Mexico, and California

    USGS Publications Warehouse

    Robertson, Frederick N.

    1991-01-01

    Chemical and isotope analyses of ground water from 28 basins in the Basin and Range physiographic province of Arizona and parts of adjacent States were used to evaluate ground-water quality, determine processes that control ground-water chemistry, provide independent insight into the hydrologic flow system, and develop information transfer. The area is characterized by north- to northwest-trending mountains separated by alluvial basins that form a regional topography of alternating mountains and valleys. On the basis of ground-water divides or zones of minimal basin interconnection, the area was divided into 72 basins, each representing an individual aquifer system. These systems are joined in a dendritic pattern and collectively constitute the major water resource in the region. Geochemical models were developed to identify reactions and mass transfer responsible for the chemical evolution of the ground water. On the basis of mineralogy and chemistry of the two major rock associations of the area, a felsic model and a mafic model were developed to illustrate geologic, climatic, and physiographic effects on ground-water chemistry. Two distinct hydrochemical processes were identified: (1) reactions of meteoric water with minerals and gases in recharge areas and (2) reactions of ground water as it moves down the hydraulic gradient. Reactions occurring in recharge and downgradient areas can be described by a 13-component system. Major reactions are the dissolution and precipitation of calcite and dolomite, the weathering of feldspars and ferromagnesian minerals, the formation of montmorillonite, iron oxyhydroxides, and probably silica, and, in some basins, ion exchange. The geochemical modeling demonstrated that relatively few phases are required to derive the ground-water chemistry; 14 phases-12 mineral and 2 gas-consistently account for the chemical evolution in each basin. The final phases were selected through analysis of X-ray diffraction and fluorescence data

  17. Recharge processes in an alluvial aquifer riparian zone, Norman Landfill, Norman, Oklahoma, 1998-2000

    USGS Publications Warehouse

    Scholl, Martha; Christenson, Scott; Cozzarelli, Isabelle; Ferree, Dale; Jaeshke, Jeanne

    2005-01-01

    Analyses of stable isotope profiles (d2H and d18O) in the saturated zone, combined with water-table fluctuations, gave a comprehensive picture of recharge processes in an alluvial aquifer riparian zone. At the Norman Landfill U.S. Geological Survey Toxic Substances Hydrology research site in Norman, Oklahoma, recharge to the aquifer appears to drive biodegradation, contributing fresh supplies of electron acceptors for the attenuation of leachate compounds from the landfill. Quantifying recharge is a first step in studying this process in detail. Both chemical and physical methods were used to estimate recharge. Chemical methods included measuring the increase in recharge water in the saturated zone, as defined by isotopic signature, specific conductance or chloride measurements; and infiltration rate estimates using storm event isotopic signatures. Physical methods included measurement of water-table rise after individual rain events and on an approximately monthly time scale. Evapotranspiration rates were estimated using diurnal watertable fluctuations; outflux of water from the alluvial aquifer during the growing season had a large effect on net recharge at the site. Evaporation and methanogenesis gave unique isotopic signatures to different sources of water at the site, allowing the distinction of recharge using the offset of the isotopic signature from the local meteoric water line. The downward movement of water from large, isotopically depleted rain events in the saturated zone yielded recharge rate estimates (2.2 - 3.3 mm/day), and rates also were determined by observing changes in thickness of the layer of infiltrated recharge water at the top of the saturated zone (1.5 - 1.6 mm/day). Recharge measured over 2 years (1998-2000) in two locations at the site averaged 37 percent of rainfall, however, part of this water had only a short residence time in the aquifer. Isotopes showed recharge water entering the ground-water system in winter and spring, then being

  18. Hydrogeologic and agricultural-chemical data for the South Skunk River alluvial aquifer at a site in Story County, Iowa, 1992-93

    USGS Publications Warehouse

    Buchmiller, R.C.

    1995-01-01

    A reconnaissance study was conducted during 1992-93 to collect background hydrogeologic and agricultural-chemical data for the South Skunk River alluvial aquifer near Ames, Iowa. Observation wells were drilled to characterize the surficial geologic materials of a field-scale study site and to provide locations for collecting waterlevel and agricultural-chemical data. Walnut Creek, a tributary to the South Skunk River, forms a lateral boundary on the northern edge of the field site. Water-level measurements showed a hydraulic-head gradient towards the South Skunk River under both wet and dry conditions at the study site. Walnut Creek appears to be losing water to the aquifer during most hydrologic conditions. More than 20 milligrams per liter of nitrate as nitrogen were present consistently in water from the southeastern part of the study site. Nitrate-as-nitrogen concentrations in water samples from other locations routinely did not exceed 10 milligrams per liter. The herbicide atrazine was detected most often, 36 of 38 times, in water samples collected from observation wells adjacent to Walnut Creek. Atrazine was not used on the study site during 1992-93 but was found frequently in water samples from Walnut Creek. Therefore, Walnut Creek appears to be a source of herbicide contamination to the alluvial aquifer.

  19. Thickness of the upper and lower confining units of the Mississippi River alluvial aquifer in northwestern Mississippi

    USGS Publications Warehouse

    Arthur, J. Kerry

    1994-01-01

    The thickness of the upper and lower confining units of the Mississippi River alluvial aquifer in north- western Mississippi (the Delta) has a significant influence on the vertical recharge and contamination susceptibility of the aquifer. The upper confining unit is thicker in the southern part of the Delta, the upper confining unit is less than 10 feet thick in small areas in Bolivar, Coahoma, Sunflower, Quit- man, and Tallahatchie Counties. The lower confining units are characterized by the geologic units directly underlying the alluvial aquifer. The geologic units directly underlying the aquifer, from youngest to oldest, are the Jackson Group, Cockfield Formation, Cook Mountain Formation, Sparta Sand, and Zilpha Clay. The lower confining unit thickness is greatest (greater than 250 feet) in southern Issaquena and northwestern Warren Counties. The largest area where the lower confining unit is less than 10 feet thick is Quitman, southern Coahoma, western Panola, southern Tunica, and the northern one-half of Sunflower Counties.

  20. Bicarbonate impact on U(VI) bioreduction in a shallow alluvial aquifer

    NASA Astrophysics Data System (ADS)

    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. F.; Gupta, Manish; Chandler, Darrell P.; Murray, Chris; Peacock, Aaron D.; Giloteaux, Ludovic; 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 sediments desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, 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 in 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

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

    SciTech Connect

    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.

  2. Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

    NASA Astrophysics Data System (ADS)

    O'Leary, David R.; Izbicki, John A.; Metzger, Loren F.

    2015-11-01

    As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency's secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100-2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

  3. Sources of high-chloride water and managed aquifer recharge in an alluvial aquifer in California, USA

    USGS Publications Warehouse

    O'Leary, David; Izbicki, John A.; Metzger, Loren F.

    2015-01-01

    As a result of pumping in excess of recharge, water levels in alluvial aquifers within the Eastern San Joaquin Groundwater Subbasin, 130 km east of San Francisco (California, USA), declined below sea level in the early 1950s and have remained so to the present. Chloride concentrations in some wells increased during that time and exceeded the US Environmental Protection Agency’s secondary maximum contaminant level of 250 mg/L, resulting in removal of some wells from service. Sources of high-chloride water include irrigation return in 16 % of sampled wells and water from delta sediments and deeper groundwater in 50 % of sampled wells. Chloride concentrations resulting from irrigation return commonly did not exceed 100 mg/L, although nitrate concentrations were as high as 25 mg/L as nitrogen. Chloride concentrations ranged from less than 100–2,050 mg/L in wells affected by water from delta sediments and deeper groundwater. Sequential electromagnetic logs show movement of high-chloride water from delta sediments to pumping wells through permeable interconnected aquifer layers. δD and δ18O data show most groundwater originated as recharge along the front of the Sierra Nevada, but tritium and carbon-14 data suggest recharge rates in this area are low and have decreased over recent geologic time. Managed aquifer recharge at two sites show differences in water-level responses to recharge and in the physical movement of recharged water with depth related to subsurface geology. Well-bore flow logs also show rapid movement of water from recharge sites through permeable interconnected aquifer layers to pumping wells.

  4. River bank geomorphology controls groundwater arsenic concentrations in aquifers adjacent to the Red River, Hanoi Vietnam

    NASA Astrophysics Data System (ADS)

    Stahl, Mason O.; Harvey, Charles F.; van Geen, Alexander; Sun, Jing; Thi Kim Trang, Pham; Mai Lan, Vi; Mai Phuong, Thao; Hung Viet, Pham; Bostick, Benjamin C.

    2016-08-01

    Many aquifers that are highly contaminated by arsenic in South and Southeast Asia are in the floodplains of large river networks. Under natural conditions, these aquifers would discharge into nearby rivers; however, large-scale groundwater pumping has reversed the flow in some areas so that rivers now recharge aquifers. At a field site near Hanoi Vietnam, we find river water recharging the aquifer becomes high in arsenic, reaching concentrations above 1000 µg/L, within the upper meter of recently (< ˜10 years) deposited riverbed sediments as it is drawn into a heavily pumped aquifer along the Red River. Groundwater arsenic concentrations in aquifers adjacent to the river are largely controlled by river geomorphology. High (>50 µg/L) aqueous arsenic concentrations are found in aquifer regions adjacent to zones where the river has recently deposited sediment and low arsenic concentrations are found in aquifer regions adjacent to erosional zones. High arsenic concentrations are even found adjacent to a depositional river reach in a Pleistocene aquifer, a type of aquifer sediment which generally hosts low arsenic water. Using geochemical and isotopic data, we estimate the in situ rate of arsenic release from riverbed sediments to be up to 1000 times the rates calculated on inland aquifer sediments in Vietnam. Geochemical data for riverbed porewater conditions indicate that the reduction of reactive, poorly crystalline iron oxides controls arsenic release. We suggest that aquifers in these regions may be susceptible to further arsenic contamination where riverine recharge drawn into aquifers by extensive groundwater pumping flows through recently deposited river sediments before entering the aquifer.

  5. Recharge processes drive sulfate reduction in an alluvial aquifer contaminated with landfill leachate

    USGS Publications Warehouse

    Scholl, M.A.; Cozzarelli, I.M.; Christenson, S.C.

    2006-01-01

    Natural attenuation of contaminants in groundwater depends on an adequate supply of electron acceptors to stimulate biodegradation. In an alluvial aquifer contaminated with leachate from an unlined municipal landfill, the mechanism of recharge infiltration was investigated as a source of electron acceptors. Water samples were collected monthly at closely spaced intervals in the top 2 m of the saturated zone from a leachate-contaminated well and an uncontaminated well, and analyzed for ??18O, ??2H, non-volatile dissolved organic carbon (NVDOC), SO42-, NO3- and Cl-. Monthly recharge amounts were quantified using the offset of the ??18O or ??2H from the local meteoric water line as a parameter to distinguish water types, as evaporation and methanogenesis caused isotopic enrichment in waters from different sources. Presence of dissolved SO42- in the top 1 to 2??m of the saturated zone was associated with recharge; SO42- averaged 2.2??mM, with maximum concentrations of 15??mM. Nitrate was observed near the water table at the contaminated site at concentrations up to 4.6??mM. Temporal monitoring of ??2H and SO42- showed that vertical transport of recharge carried SO42- to depths up to 1.75??m below the water table, supplying an additional electron acceptor to the predominantly methanogenic leachate plume. Measurements of ??34S in SO42- indicated both SO42- reduction and sulfide oxidation were occurring in the aquifer. Depth-integrated net SO42- reduction rates, calculated using the natural Cl- gradient as a conservative tracer, ranged from 7.5 ?? 10- 3 to 0.61??mM??d- 1 (over various depth intervals from 0.45 to 1.75??m). Sulfate reduction occurred at both the contaminated and uncontaminated sites; however, median SO42- reduction rates were higher at the contaminated site. Although estimated SO42- reduction rates are relatively high, significant decreases in NVDOC were not observed at the contaminated site. Organic compounds more labile than the leachate NVDOC may be

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

    USGS Publications Warehouse

    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.A three-dimensional hydrogeologic framework was constructed that defines the physical geometry and rock types through which groundwater moves. The diverse sedimentary units of the GBCAAS study area are grouped into hydrogeologic units (HGUs) that are inferred to have reasonably distinct hydrologic properties due to their physical characteristics. These HGUs are commonly disrupted by large-magnitude offset thrust, strike-slip, and normal faults, and locally affected by caldera formation. The most permeable aquifer materials within the study area include Cenozoic unconsolidated sediments and volcanic rocks, along with Mesozoic and Paleozoic carbonate rocks. The framework was built by extracting and combining information from digital elevation models, geologic maps, cross sections, drill hole logs, existing hydrogeologic frameworks, and geophysical data.

  7. Hydrogeology and water quality in the Snake River alluvial aquifer at Jackson Hole Airport, Jackson, Wyoming, September 2008-June 2009

    USGS Publications Warehouse

    Wright, Peter R.

    2010-01-01

    The hydrogeology and water quality of the Snake River alluvial aquifer, at the Jackson Hole Airport in northwest Wyoming, was studied by the U.S. Geological Survey in cooperation with the Jackson Hole Airport Board and the Teton Conservation District during September 2008-June 2009. Hydrogeologic conditions were characterized using data collected from 14 Jackson Hole Airport wells. Groundwater levels are summarized in this report and the direction of groundwater flow, hydraulic gradients, and estimated groundwater velocity rates in the Snake River alluvial aquifer underlying the study area are presented. Analytical results of chemical, dissolved gas, and stable isotopes are presented and summarized. Seasonally, the water table at Jackson Hole Airport was lowest in early spring and reached its peak in July, with an increase of 12 to 14 feet between April and July 2009. Groundwater flow was predominantly horizontal but had the hydraulic potential for downward flow. The direction of groundwater flow was from the northeast to the west-southwest. Horizontal groundwater velocities within the Snake River alluvial aquifer at the airport were estimated to be about 26 to 66 feet per day. This indicates that the traveltime from the farthest upgradient well to the farthest downgradient well was approximately 53 to 138 days. This estimate only describes the movement of groundwater because some solutes may move at a rate much slower than groundwater flow through the aquifer. The quality of the water in the alluvial aquifer generally was considered good. The alluvial aquifer was a fresh, hard to very hard, calcium carbonate type water. No constituents were detected at concentrations exceeding U.S. Environmental Protection Agency Maximum Contaminant Levels, and no anthropogenic compounds were detected at concentrations greater than laboratory reporting levels. The quality of groundwater in the alluvial aquifer generally was suitable for domestic and other uses; however, dissolved

  8. Biogeochemistry at a wetland sediment-alluvial aquifer interface in a landfill leachate plume

    USGS Publications Warehouse

    Lorah, M.M.; Cozzarelli, I.M.; Böhlke, J.K.

    2009-01-01

    The biogeochemistry at the interface between sediments in a seasonally ponded wetland (slough) and an alluvial aquifer contaminated with landfill leachate was investigated to evaluate factors that can effect natural attenuation of landfill leachate contaminants in areas of groundwater/surface-water interaction. The biogeochemistry at the wetland-alluvial aquifer interface differed greatly between dry and wet conditions. During dry conditions (low water table), vertically upward discharge was focused at the center of the slough from the fringe of a landfill-derived ammonium plume in the underlying aquifer, resulting in transport of relatively low concentrations of ammonium to the slough sediments with dilution and dispersion as the primary attenuation mechanism. In contrast, during wet conditions (high water table), leachate-contaminated groundwater discharged upward near the upgradient slough bank, where ammonium concentrations in the aquifer where high. Relatively high concentrations of ammonium and other leachate constituents also were transported laterally through the slough porewater to the downgradient bank in wet conditions. Concentrations of the leachate-associated constituents chloride, ammonium, non-volatile dissolved organic carbon, alkalinity, and ferrous iron more than doubled in the slough porewater on the upgradient bank during wet conditions. Chloride, non-volatile dissolved organic carbon (DOC), and bicarbonate acted conservatively during lateral transport in the aquifer and slough porewater, whereas ammonium and potassium were strongly attenuated. Nitrogen isotope variations in ammonium and the distribution of ammonium compared to other cations indicated that sorption was the primary attenuation mechanism for ammonium during lateral transport in the aquifer and the slough porewater. Ammonium attenuation was less efficient, however, in the slough porewater than in the aquifer and possibly occurred by a different sorption mechanism. A

  9. Ground-water levels in and pumpage from the alluvial aquifer at Louisville, Kentucky, May 1989-May 1991

    USGS Publications Warehouse

    Unthank, Michael D.

    1995-01-01

    Water-level data have been collected in the alluvial aquifer at Louisville, Ky., by the U.S. Geological Survey since 1943. Interpretations of these data are published periodically to update the record and help local officials manage this ground-water supply. Maps and hydrographs are presented on two sheets to aid in the interpretation of water-level changes for the period May 1989-May 1991. The altitude of the water table in the alluvial aquifer has increased as much as 5 feet in some areas during the 2-year period of May 1989-May 1991. Hydrographs for obser- vation wells throughout the alluvial aquifer show that water levels fluctuate seasonally and in response to wet and dry periods; overall, the water- level trend has been upward in recent years. Water levels in the downtown area are affected by the pumping of ground water to heat and cool several buildings in the area. Ground-water contour maps show induced infiltration of water from the Ohio River to the alluvial aquifer in downtown Louisville as a result of the ground-water pumping.

  10. Ground-water levels in the alluvial aquifer at Louisville, Kentucky, 1982-87

    USGS Publications Warehouse

    Faust, R.J.; Lyverse, M.A.

    1987-01-01

    Water level data have been collected in the alluvial aquifer at Louisville, Kentucky by the U.S. Geological Survey since 1943. Interpretations of these data have been published in several reports by the Survey, but none have been published since 1983. Contour maps and hydrographs are presented in this report to document and to help interpret water level changes for the period 1982-87. Maps and hydrographs show that groundwater levels generally stabilized in the 1980 's after rising for many years. Two areas of groundwater withdrawals are apparent in the maps and hydrographs. Withdrawals in an industrial area in west Louisville disrupt the typical pattern of the contours to curve landward around the area of withdrawal. Resumption of pumping of groundwater for heating and cooling of some buildings in the downtown area in 1985 caused declines of about 3 to 4 ft in the downtown area. (Author 's abstract)

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

    USGS Publications Warehouse

    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

  12. Agricultural chemicals in alluvial aquifers in Missouri after the 1993 flood

    USGS Publications Warehouse

    Heimann, D.C.; Richards, J.M.; Wilkison, D.H.

    1997-01-01

    Intense rains produced flooding during the spring and summer of 1993 over much of the midwestern USA including many agricultural areas of Missouri. Because of potential contamination from floodwater, an investigation was conducted to determine the changes in concentrations of agricultural chemicals in water samples from alluvial wells in Missouri after the flood. Water samples from 80 alluvial wells with historical data were collected in March, July, and November 1994, and analyzed for dissolved herbicides, herbicide metabolites, and nitrate (NO3). There were no statistically significant differences in the distribution of alachlor ((2,chloro-2'-6'-diethyl-N-[methoxymethyl]acetanilide), atrazine (2-chloro- 4-ethylamino-6-isopropylamino-1, 3, 5 triazine), and nitrate concentrations between pre- and postflood samples (?? = 0.05). The detection frequency of alachlor and atrazine in postflood samples was generally lower than the frequency in preflood samples. Analyses of agricultural chemicals in water samples from an intensely sampled well field indicate significant differences between the distribution of dissolved P concentrations in pre- and postflood samples (?? = 0.05). However, no significant differences were detected between the pre- and postflood distributions of NO3 or ammonia concentrations. Because of the numerous sources of temporal variability and the relatively short record of water-quality data for the study wells, a cause-and-effect relation between changes in agricultural chemical concentrations and a single factor of the 1993 flood is difficult to determine. Based on the results of this study, the 1993 flood did not cause widespread or long-term significant changes in concentrations of agricultural chemicals in water from alluvial aquifers in Missouri.

  13. Spatial distribution of triazine residues in a shallow alluvial aquifer linked to groundwater residence time.

    PubMed

    Sassine, Lara; Le Gal La Salle, Corinne; Khaska, Mahmoud; Verdoux, Patrick; Meffre, Patrick; Benfodda, Zohra; Roig, Benoît

    2016-07-22

    At present, some triazine herbicides occurrence in European groundwater, 13 years after their use ban in the European Union, remains of great concern and raises the question of their persistence in groundwater systems due to several factors such as storage and remobilization from soil and unsaturated zone, limited or absence of degradation, sorption in saturated zones, or to continuing illegal applications. In order to address this problem and to determine triazine distribution in the saturated zone, their occurrence is investigated in the light of the aquifer hydrodynamic on the basis of a geochemical approach using groundwater dating tracers ((3)H/(3)He). In this study, atrazine, simazine, terbuthylazine, deethylatrazine, deisopropylatrazine, and deethylterbuthylazine are measured in 66 samples collected between 2011 and 2013 from 21 sampling points, on the Vistrenque shallow alluvial aquifer (southern France), covered by a major agricultural land use. The frequencies of quantification range from 100 to 56 % for simazine and atrazine, respectively (LQ = 1 ng L(-1)). Total triazine concentrations vary between 15 and 350 ng L(-1) and show three different patterns with depth below the water table: (1) low concentrations independent of depth but related to water origin, (2) an increase in concentrations with depth in the aquifer related to groundwater residence time and triazine use prior to their ban, and (3) relatively high concentrations at low depths in the saturated zone more likely related to a slow desorption of these compounds from the soil and unsaturated zone. The triazine attenuation rate varies between 0.3 for waters influenced by surface water infiltration and 4.8 for water showing longer residence times in the aquifer, suggesting an increase in these rates with water residence time in the saturated zone. Increasing triazine concentrations with depth is consistent with a significant decrease in the use of these pesticides for the last 10

  14. Appraising options to reduce shallow groundwater tables and enhance flow conditions over regional scales in an irrigated alluvial aquifer system

    NASA Astrophysics Data System (ADS)

    Morway, Eric D.; Gates, Timothy K.; Niswonger, Richard G.

    2013-07-01

    Some of the world’s key agricultural production systems face big challenges to both water quantity and quality due to shallow groundwater that results from long-term intensive irrigation, namely waterlogging and salinity, water losses, and environmental problems. This paper focuses on water quantity issues, presenting finite-difference groundwater models developed to describe shallow water table levels, non-beneficial groundwater consumptive use, and return flows to streams across two regions within an irrigated alluvial river valley in southeastern Colorado, USA. The models are calibrated and applied to simulate current baseline conditions in the alluvial aquifer system and to examine actions for potentially improving these conditions. The models provide a detailed description of regional-scale subsurface unsaturated and saturated flow processes, thereby enabling detailed spatiotemporal description of groundwater levels, recharge to infiltration ratios, partitioning of ET originating from the unsaturated and saturated zones, and groundwater flows, among other variables. Hybrid automated and manual calibration of the models is achieved using extensive observations of groundwater hydraulic head, groundwater return flow to streams, aquifer stratigraphy, canal seepage, total evapotranspiration, the portion of evapotranspiration supplied by upflux from the shallow water table, and irrigation flows. Baseline results from the two regional-scale models are compared to model predictions under variations of four alternative management schemes: (1) reduced seepage from earthen canals, (2) reduced irrigation applications, (3) rotational lease fallowing (irrigation water leased to municipalities, resulting in temporary dry-up of fields), and (4) combinations of these. The potential for increasing the average water table depth by up to 1.1 and 0.7 m in the two respective modeled regions, thereby reducing the threat of waterlogging and lowering non-beneficial consumptive use

  15. Appraising options to reduce shallow groundwater tables and enhance flow conditions over regional scales in an irrigated alluvial aquifer system

    USGS Publications Warehouse

    Morway, Eric D.; Gates, Timothy K.; Niswonger, Richard G.

    2013-01-01

    Some of the world’s key agricultural production systems face big challenges to both water quantity and quality due to shallow groundwater that results from long-term intensive irrigation, namely waterlogging and salinity, water losses, and environmental problems. This paper focuses on water quantity issues, presenting finite-difference groundwater models developed to describe shallow water table levels, non-beneficial groundwater consumptive use, and return flows to streams across two regions within an irrigated alluvial river valley in southeastern Colorado, USA. The models are calibrated and applied to simulate current baseline conditions in the alluvial aquifer system and to examine actions for potentially improving these conditions. The models provide a detailed description of regional-scale subsurface unsaturated and saturated flow processes, thereby enabling detailed spatiotemporal description of groundwater levels, recharge to infiltration ratios, partitioning of ET originating from the unsaturated and saturated zones, and groundwater flows, among other variables. Hybrid automated and manual calibration of the models is achieved using extensive observations of groundwater hydraulic head, groundwater return flow to streams, aquifer stratigraphy, canal seepage, total evapotranspiration, the portion of evapotranspiration supplied by upflux from the shallow water table, and irrigation flows. Baseline results from the two regional-scale models are compared to model predictions under variations of four alternative management schemes: (1) reduced seepage from earthen canals, (2) reduced irrigation applications, (3) rotational lease fallowing (irrigation water leased to municipalities, resulting in temporary dry-up of fields), and (4) combinations of these. The potential for increasing the average water table depth by up to 1.1 and 0.7 m in the two respective modeled regions, thereby reducing the threat of waterlogging and lowering non-beneficial consumptive use

  16. Hydrologic setting and geochemical characterization of free-phase hydrocarbons in the alluvial aquifer at Mandan, North Dakota, November 2000

    USGS Publications Warehouse

    Hostettler, Frances D.; Rostad, Colleen E.; Kvenvolden, Keith A.; Delin, Geoffrey N.; Putnam, Larry D.; Kolak, Jonathan J.; Chaplin, Brain P.; Schaap, Bryan D.

    2001-01-01

    Free-phase hydrocarbons are present in the alluvial aquifer at Mandan, North Dakota. A large contaminant body of the hydrocarbons [light nonaqueous phase liquid (LNAPL)] floats on the water table about 20 feet below land surface. The main LNAPL body is about 6 feet thick, and the areal extent is about 657,000 square feet. A study was conducted to describe the hydrologic setting and characterize the geochemical composition of the free-phase hydrocarbons in the alluvial aquifer. Most of the study area is underlain by alluvium of the Heart River Valley that ranges in thickness from about 25 to 109 feet. The alluvium can be divided into three stratigraphic units--silty clay, silty sand, and sand--and is underlain by shales and sandstones. Monitoring wells were installed prior to this study, to an average depth of about 29 feet. Regional ground-water flow in the Heart River aquifer generally may be from west-northwest to east-southeast and is influenced by hydraulic connections to the river. Hydraulic connections also are probable between the aquifer and the Missouri River. Ground-water flow across the north boundary of the aquifer is minimal because of adjacent shales and sandstones of relatively low permeability. Recharge occurs from infiltration of precipitation and is spatially variable depending on the thickness of overlying clays and silts. Although the general water-table gradient may be from west-northwest to east-southeast, the flow directions can vary depending on the river stage and recharge events. Any movement of the LNAPL is influenced by the gradients created by changes in water-level altitudes. LNAPL samples were collected from monitoring wells using dedicated bailers. The samples were transferred to glass containers, stored in the dark, and refrigerated before shipment for analysis by a variety of analytical techniques. For comparison purposes, reference-fuel samples provided by the refinery in Mandan also were analyzed. These reference-fuel samples

  17. Inference of lithologic distributions in an alluvial aquifer using airborne transient electromagnetic surveys

    USGS Publications Warehouse

    Dickinson, Jesse E.; Pool, D.R.; Groom, R.W.; Davis, L.J.

    2010-01-01

    An airborne transient electromagnetic (TEM) survey was completed in the Upper San Pedro Basin in southeastern Arizona to map resistivity distributions within the alluvial aquifer. This investigation evaluated the utility of 1D vertical resistivity models of the TEM data to infer lithologic distributions in an alluvial aquifer. Comparisons of the resistivity values and layers in the 1D resistivity models of airborne TEM data to 1D resistivity models of ground TEM data, borehole resistivity logs, and lithologic descriptions in drill logs indicated that the airborne TEM identified thick conductive fine-grained sediments that result in semiconfined groundwater conditions. One-dimensional models of ground-based TEM surveys and subsurface lithology at three sites were used to determine starting models and constraints to invert airborne TEM data using a constrained Marquardt-styleunderparameterized method. A maximum structural resolution of six layers underlain by a half-space was determined from the resistivity structure of the 1D models of the ground TEM data. The 1D resistivity models of the airborne TEM data compared well with the control data to depths of approximately 100 m in areas of thick conductive silt and clay and to depths of 200 m in areas of resistive sand and gravel. Comparison of a 3D interpolation of the 1D resistivity models to drill logs indicated resistive (mean of 65 ohm-m ) coarse-grained sediments along basin margins and conductive (mean of 8 ohm-m ) fine-grained sediments at the basin center. Extents of hydrologically significant thick silt and clay were well mapped by the 1D resistivity models of airborne TEM data. Areas of uncertain lithology remain below conductive fine-grained sediments where the 1D resistivity structure is not resolved: in areas where multiple lithologies have similar resistivity values and in areas of high salinity.

  18. Identification of recharge zones in the Lower Mississippi River alluvial aquifer using high-resolution precipitation estimates

    NASA Astrophysics Data System (ADS)

    Dyer, Jamie; Mercer, Andrew; Rigby, James R.; Grimes, Alexandria

    2015-12-01

    Water resources in the lower Mississippi River alluvial valley play a critical role in agricultural productivity due to the widespread use of irrigation during the growing season. However, the unknown specifics of surface-atmosphere feedbacks in the region, along with diminishing groundwater availability and the non-sustainable trend in irrigation draws from the alluvial aquifer, makes it difficult for water resource managers to make sound decisions for future water sustainability. As a result, it is crucial to identify spatial and temporal associations between local rainfall patterns and groundwater levels to determine the influence of precipitation on regional aquifer recharge. Specifically, it is critical to define the recharge zones of the aquifer so that rainfall distribution can be used to assess potential groundwater recovery. This project addresses the issue of defining areas of recharge in the lower Mississippi River alluvial aquifer (LMRAA) through an assessment of historical precipitation variability using high-resolution radar-derived precipitation estimates. A rotated principal component analysis (RPCA) of both groundwater and precipitation data from October through April is used to define locations where aquifer levels show the greatest variability, with a stepwise regression approach used to define areas where rainfall and groundwater levels show the strongest association. Results show that the greatest recharge through direct rainfall is along the Tallahatchie River basin in the northeastern Mississippi Delta, with recharge along the periphery of the LMRAA likely a result of direct water flux from surface hydrologic features.

  19. Occurrence, Distribution, Sources, and Trends of Elevated Chloride Concentrations in the Mississippi River Valley Alluvial Aquifer in Southeastern Arkansas

    USGS Publications Warehouse

    Kresse, Timothy M.; Clark, Brian R.

    2008-01-01

    Water-quality data from approximately 2,500 sites were used to investigate the distribution of chloride concentrations in the Mississippi River Valley alluvial aquifer in southeastern Arkansas. The large volume and areal distribution of the data used for the investigation proved useful in delineating areas of elevated (greater than 100 milligrams per liter) chloride concentrations, assessing potential sources of saline water, and evaluating trends in chloride distribution and concentration over time. Irrigation water containing elevated chloride concentrations is associated with negative effects to rice and soybeans, two of the major crops in Arkansas, and a groundwater chloride concentration of 100 milligrams per liter is recommended as the upper limit for use on rice. As such, accurately delineating areas with high salinity ground water, defining potential sources of chloride, and documenting trends over time is important in assisting the agricultural community in water management. The distribution and range of chloride concentrations in the study area revealed distinct areas of elevated chloride concentrations. Area I includes an elongated, generally northwest-southeast trending band of moderately elevated chloride concentrations in the northern part of the study area. This band of elevated chloride concentrations is approximately 40 miles in length and varies from approximately 2 to 9 miles in width, with a maximum chloride concentration of 360 milligrams per liter. Area II is a narrow, north-south trending band of elevated chloride concentrations in the southern part of the study area, with a maximum chloride concentration of 1,639 milligrams per liter. A zone of chloride concentrations exceeding 200 milligrams per liter is approximately 25 miles in length and 5 to 6 miles in width. In Area I, low chloride concentrations in samples from wells completed in the alluvial aquifer next to the Arkansas River and in samples from the upper Claiborne aquifer, which

  20. Regional groundwater-flow model of the Redwall-Muav, Coconino, and alluvial basin aquifer systems of northern and central Arizona

    USGS Publications Warehouse

    Pool, D.R.; Blasch, Kyle W.; Callegary, James B.; Leake, Stanley A.; Graser, Leslie F.

    2011-01-01

    A numerical flow model (MODFLOW) of the groundwater flow system in the primary aquifers in northern Arizona was developed to simulate interactions between the aquifers, perennial streams, and springs for predevelopment and transient conditions during 1910 through 2005. Simulated aquifers include the Redwall-Muav, Coconino, and basin-fill aquifers. Perennial stream reaches and springs that derive base flow from the aquifers were simulated, including the Colorado River, Little Colorado River, Salt River, Verde River, and perennial reaches of tributary streams. Simulated major springs include Blue Spring, Del Rio Springs, Havasu Springs, Verde River headwater springs, several springs that discharge adjacent to major Verde River tributaries, and many springs that discharge to the Colorado River. Estimates of aquifer hydraulic properties and groundwater budgets were developed from published reports and groundwater-flow models. Spatial extents of aquifers and confining units were developed from geologic data, geophysical models, a groundwater-flow model for the Prescott Active Management Area, drill logs, geologic logs, and geophysical logs. Spatial and temporal distributions of natural recharge were developed by using a water-balance model that estimates recharge from direct infiltration. Additional natural recharge from ephemeral channel infiltration was simulated in alluvial basins. Recharge at wastewater treatment facilities and incidental recharge at agricultural fields and golf courses were also simulated. Estimates of predevelopment rates of groundwater discharge to streams, springs, and evapotranspiration by phreatophytes were derived from previous reports and on the basis of streamflow records at gages. Annual estimates of groundwater withdrawals for agriculture, municipal, industrial, and domestic uses were developed from several sources, including reported withdrawals for nonexempt wells, estimated crop requirements for agricultural wells, and estimated per

  1. Ground-water data for the alluvial, buried channel, Basel Pleistocene and Dakota aquifer in West-Central Iowa

    USGS Publications Warehouse

    Hunt, Pamela K.B.; Runkle, Donna L.

    1985-01-01

    The purpose of this investigation was to determine the availability, quantity and quality of groundwater from three principal aquifers in West-Central Iowa, the alluvial, buried channel, Basal Pleistocene and the Dakota aquifers. Specific objectives were to: (1) determine the location, extent and the nature of these aquifers; (2) evaluate the occurrence and movement of groundwater, including the sources of recharge and discharge; (3) estimate the quantities of water stored in the aquifers; (4) estimate the potential yields of wells tapping the aquifers; (5) estimate the water use; and (6) describe the chemical quality of the groundwater. This report is the compilation of the data collected during the investigation and has the purpose of providing a reference for an interpretive report describing groundwater resources and a bedrock topography map of the study area.

  2. Groundwater monitoring plan for the Missouri River alluvial aquifer in the vicinity of the City of Independence, Missouri, well field

    USGS Publications Warehouse

    Wilkison, Donald H.

    2012-01-01

    Source contributions to monitoring and supply wells, contributing recharge areas, groundwater travel times, and current (2012) understanding of alluvial water quality were used to develop a groundwater monitoring plan for the Missouri River alluvial aquifer in the vicinity of the City of Independence, Missouri well field. The plan was designed to evaluate long-term alluvial water quality and assess potential changes in, and threats to, well-field water quality. Source contributions were determined from an existing groundwater flow model in conjunction with particle-tracking analysis and verified with water-quality data collected from 1997 through 2010 from a network of 68 monitoring wells. Three conjunctive factors - well-field pumpage, Missouri River discharge, and aquifer recharge - largely determined groundwater flow and, therefore, source contributions. The predominant source of groundwater to most monitoring wells and supply wells is the Missouri River, and this was reflected, to some extent, in alluvial water quality. To provide an estimate of the maximum potential lead time available for remedial action, monitoring wells where groundwater travel times from the contributing recharge areas are less than 2 years and predominately singular sources (such as the Missouri River or the land surface) were selected for annual sampling. The sample interval of the remaining wells, which have varying travel times and intermediate mixtures of river and land-surface contributions, were staggered on a 2-, 3-, or 4-year rotation. This was done to provide data from similar contributing areas and account for inherent aquifer variability yet minimize sample redundancy.

  3. Intelligent mapping of alluvial aquifer characteristics in the Otago region, New Zealand

    NASA Astrophysics Data System (ADS)

    Friedel, Michael; Rawlinson, Zara; Westerhoff, Rogier

    2015-04-01

    We adopt a hybrid approach to map the 3D hydrostratigraphy of an alluvial aquifer using big data collected in the Ettrick basin, Otago New Zealand. First, a subset (1%) of the 18 million regional helicopter frequency-domain electromagnetic (HEM) sounding measurements (300 Hz, Horizontal co-planar; 3300 Hz, vertical co-planar; 8200 Hz, horizontal co-planar; 40 kHz, horizontal co-planar; 137 kHz horizontal coplanar) and their numerically-inverted 1D resistivity (50¬-100 Ω-m) profiles are randomly split. For example, 50% of these data are used for training an unsupervised machine-learning (ML) network, and 50% of these data are used for performance at independent locations. The remaining set of HEM measurements are then presented to the vetted ML network to estimate regional resistivity structure which is compared to previously inverted resistivity. Second, about 50 borehole autocorrelation functions are computed based on cross-component correlations of quantized borehole locations sampled for lithology and HEM sounding data. Third, an unsupervised ML network is trained and performance tested using sparse borehole lithology (fractions of sand, silt, clay, mudstone, schist) and hydraulic properties (storage, hydraulic conductivity), and those HEM sounding data occurring within a radius defined by the maximum borehole autocorrelation distances. Fourth, this ML network is then used together with independent HEM sounding measurements to map the spatial distribution of physical aquifer properties and hydraulic properties across the basin.

  4. Sensitivity and resolution of tomographic pumping tests in an alluvial aquifer

    USGS Publications Warehouse

    Bohling, G.C.

    2009-01-01

    Various investigators have proposed hydraulic tomography, the simultaneous analysis of responses to multiple well tests, as a means to obtain a high-resolution characterization of aquifer flow properties. This study assesses the information content of drawdown records from a set of tomographic pumping tests in an alluvial aquifer, comparing the parameter sensitivity and resolution associated with transient and steady-shape formulations of the objective function for the parameter estimation problem. The steady-shape approach takes advantage of the rapid establishment of constant gradients within the region surrounding a pumping well, comparing observed drawdown differences within this region with drawdown differences predicted by a steady state model. Both the transient and steady-shape approaches resolve K variations only within a limited distance of the pumping intervals and observation points. Relative to the transient approach, the steady-shape approach reduces the influence of poorly resolved property variations, including K variations outside the region of investigation and storage coefficient variations throughout the model domain. Copyright 2009 by the American Geophysical Union.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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

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

    PubMed

    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

  8. Preliminary assessment of the ground-water resources of the alluvial aquifer, White River valley, Rio Blanco County, Colorado

    USGS Publications Warehouse

    Van Liew, W. P.; Gesink, M.L.

    1985-01-01

    A preliminary study of the alluvial aquifer in the White River Valley was conducted to assess aquifer extent and the occurrence , availability, and chemical quality of water in the aquifer. The aquifer in the study area underlies 35 square miles. Aquifer width ranges from 0.1 to 1.5 miles and averages 0.5 miles. Saturated thickness ranges from zero to more than 140 feet and averages 22 feet. The aquifer is unconfined except west of the Grand Hogback, where artesian conditions were observed at several locations. Well yields usually are less than 25 gallons per minute. At the Meeker municipal well field in Agency Park, wells reportedly could yield more than 1,000 gallons per minute each. Based on nine aquifer tests, transmissivity ranges from 860 to 93,000 feet squared per day, and hydraulic conductivity ranges from 70 to 1,550 feet per day. The estimated total volume of water in storage in the aquifer in the study area is 103,000 acre-feet. Groundwater type in the eastern part of the study area is calcium bicarbonate; to the west, water type is sodium sulfate. Water in the aquifer is classified as very hard throughout the study area. Specific conductance generally increases from east to west. (USGS)

  9. Distribution of rare earth elements in an alluvial aquifer affected by acid mine drainage: the Guadiamar aquifer (SW Spain).

    PubMed

    Olías, M; Cerón, J C; Fernández, I; De la Rosa, J

    2005-05-01

    This work analyses the spatial distribution, the origin, and the shale-normalised fractionation patterns of the rare earth elements (REE) in the alluvial aquifer of the Guadiamar River (south-western Spain). This river received notoriety in April 1998 for a spill that spread a great amount of slurry (mainly pyrites) and acid waters in a narrow strip along the river course. Groundwaters and surface waters were sampled to analyse, among other elements, the REEs. Their spatial distribution shows a peak close to the mining region, in an area with low values of pH and high concentrations of sulphates and other metals such as Zn, Cu, Co, Ni, Pb, and Cd. The patterns of shale-normalised fractionation at the most-contaminated points show an enrichment in the middle rare earth elements (MREE) with respect to the light (LREE) and heavy (HREE) ones, typical of acid waters. The Ce-anomaly becomes more negative as pH increases, due to the preferential fractionation of Ce in oxyhydroxides of Fe.

  10. Spatial characterization of hydraulic conductivity of perialpine alluvial gravel-and-sand aquifers

    NASA Astrophysics Data System (ADS)

    Diem, Samuel; Vogt, Tobias; Höhn, Eduard

    2010-05-01

    For many hydrogeological and modeling problems on a scale of the order of 10-100 m, an assessment of the spatial distribution of hydraulic conductivity is of great importance. This is one of the tasks of the RECORD project (Restored Corridor Dynamics) of CCES (Competence Center Environment and Sustainability of the ETH Domain). This project aims to understand, how river restoration measures affect river - river corridor - groundwater systems in hydrologic and ecologic terms. The river Thur and the alluvial gravel-and-sand aquifer of the perialpine Thur valley flood plain were chosen for field investigations. In this aquifer, the distribution of hydraulic conductivity at the required scale has not yet been investigated. Thus, the aim of this work is to assess the spatial distribution of hydraulic conductivity of the aquifer on a scale of the order of 10-100 m. To accomplish this, four methods were applied on different scales. Comparing the results of the different methods should lead to an optimization of future hydraulic investigations in alpine and perialpine alluvial gravel-and-sand aquifers. The different methods were applied at a test site in the central part of the valley (Widen, Felben-Wellhausen/TG), which was instrumented with a total of 18 piezometers, covering an approximately 10×20 m area (aquifer thickness, 7 m). The gravel samples of the pre-liminary core drillings were sieved and out of the grain size distributions hydraulic conductivity was calculated (decimeter scale). Further, work included the conduction and analysis of a pumping test (decameter scale), flowmeter logs and multilevel slug tests (meter scale) with appropriate methods. A statistical evaluation of the values of hydraulic conductivity from the above methods showed that the results are quite diverse. Thus, the choice of the method to assess the distribution of hydraulic conductivity has to be done according to the problem and the required level of detail. The following recommendations

  11. Estimating mountain block recharge to downstream alluvial aquifers from standard methods

    NASA Astrophysics Data System (ADS)

    Kao, Yu-Hsuan; Liu, Chen-Wuing; Wang, Sheng-Wei; Lee, Cheng-Haw

    2012-03-01

    SummaryThe purpose of the study is to assess the applicability in estimating the mountain block recharge (MBR) to the downstream alluvial aquifers in the sub-tropical area using baseflow separation and rainfall infiltration methods. The Choushui-Wu River basin, the largest groundwater region in Taiwan was the study area. The high slope mountainous catchment located in the upstream of Choushui-Wu River basin, act as an important conduit in conveying surface and subsurface runoff to the recharge of the downstream alluvial aquifers. Geographic Information Systems (GISs) was applied to facilitate the estimation processes. The estimated MBR using the baseflow separation method was 1.08 × 109 m3/year of which Wu River and Choushui River basins comprised 0.27 × 109 m3/year (25.2%) and 0.81 × 109 m3/year (74.8%), respectively. These results are similar to the previous O18 isotopic study indicating that 22% and 78% were from the Wu River and Choushui River basins, respectively. Moreover, the estimated amount of lateral flow using C14 technique from the upstream of Choushui River basin was 0.83 × 109 m3/year, which is close to the result (0.81 × 109 m3/year) of this study. For comparison, groundwater recharged by rainfall infiltration in the mountainous catchment was derived from the precipitation, evapotranspiration, land use and soil types of the region. The estimated MBR by the rainfall infiltration method is 1.06 × 109 m3/year, which is close to 1.08 × 109 m3/year determined by the baseflow separation method. These results are also similar to the groundwater hydrograph analysis. The proposed methods show simple and efficient computation and do not require complex hydrological modeling and detailed knowledge of soil characteristics. They can reasonably estimate the lateral boundary influx contributing from the MBR and are thus applicable to estimate the MBRs in other sub-tropical regions.

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

    NASA Astrophysics Data System (ADS)

    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

  13. Setback distances between small biological wastewater treatment systems and drinking water wells against virus contamination in alluvial aquifers.

    PubMed

    Blaschke, A P; Derx, J; Zessner, M; Kirnbauer, R; Kavka, G; Strelec, H; Farnleitner, A H; Pang, L

    2016-12-15

    Contamination of groundwater by pathogenic viruses from small biological wastewater treatment system discharges in remote areas is a major concern. To protect drinking water wells against virus contamination, safe setback distances are required between wastewater disposal fields and water supply wells. In this study, setback distances are calculated for alluvial sand and gravel aquifers for different vadose zone and aquifer thicknesses and horizontal groundwater gradients. This study applies to individual households and small settlements (1-20 persons) in decentralized locations without access to receiving surface waters but with the legal obligation of biological wastewater treatment. The calculations are based on Monte Carlo simulations using an analytical model that couples vertical unsaturated and horizontal saturated flow with virus transport. Hydraulic conductivities and water retention curves were selected from reported distribution functions depending on the type of subsurface media. The enteric virus concentration in effluent discharge was calculated based on reported ranges of enteric virus concentration in faeces, virus infectivity, suspension factor, and virus reduction by mechanical-biological wastewater treatment. To meet the risk target of <10(-4)infections/person/year, a 12 log10 reduction was required, using a linear dose-response relationship for the total amount of enteric viruses, at very low exposure concentrations. The results of this study suggest that the horizontal setback distances vary widely ranging 39 to 144m in sand aquifers, 66-289m in gravel aquifers and 1-2.5km in coarse gravel aquifers. It also varies for the same aquifers, depending on the thickness of the vadose zones and the groundwater gradient. For vulnerable fast-flow alluvial aquifers like coarse gravels, the calculated setback distances were too large to achieve practically. Therefore, for this category of aquifer, a high level of treatment is recommended before the

  14. Occurrence of volatile organic compounds in shallow alluvial aquifers of a Mediterranean region: Baseline scenario and ecological implications.

    PubMed

    Di Lorenzo, T; Borgoni, R; Ambrosini, R; Cifoni, M; Galassi, D M P; Petitta, M

    2015-12-15

    A regional survey of eight volatile organic compounds (VOCs), namely BTEX (benzene, toluene, ethylbenzene and p-xylene) and four chlorinated aliphatic hydrocarbons (CAHs: chloroform, 1,2-dichloroethane, trichloroethene and tetrachloroethene), was carried out at 174 sites, in 17 alluvial aquifers of Abruzzo, a Mediterranean region of southern Italy, from 2004 to 2009. Frequency of detection, concentration range, spatial distribution pattern, and temporal trend of contaminant concentration in each aquifer were analyzed as well as the relationships between VOC concentrations and the total amount of precipitation during the 90days preceding each sampling date. A review of published ecotoxicological data, providing an indication of the biological risk associated with the observed levels of VOC contamination, was presented and discussed. BTEX concentrations were under detection limits in all the investigated aquifers, indicating absence of contamination. In contrast, CAH contamination occurred in 14 out of 17 aquifers. The two most frequently detected compounds were chloroform and tetrachloroethene. No significant temporal trend was observed for chloroform and tetrachloroethene concentrations during the six years of observation, indicating the persistence of stable contaminations, except for some slightly decreasing trends observed in three out of 17 aquifers. In four aquifers chloroform and tetrachloroethene concentrations increased with precipitations in the preceding months. Spatial patterns of contamination differed among aquifers, indicating highly complex contaminant distributions at aquifer scale not related to single-plume geometries. Patterns of contamination by chloroform and tetrachloroethene in the most urbanized aquifers were likely associated with multiple sources of VOCs not clearly detectable at the scale used in this study. In five out of 17 aquifers, chloroform and tetrachloroethene co-occurred at concentrations that are lethal to groundwater

  15. The use of MRS in the determination of hydraulic transmissivity: The case of alluvial aquifers

    NASA Astrophysics Data System (ADS)

    Plata, Juan L.; Rubio, Félix M.

    2008-12-01

    Magnetic Resonance Sounding (MRS) is nowadays accepted as a new geophysical method that can be used for a reliable determination of the ground water content distribution in the top 150 m. A great effort has also been made in MRS development to deduce the hydraulic transmissivity, based on empiric relationships of the permeability with a factor F which is calculated with NMR parameters measured at laboratory scale. To use this relationship under field conditions a calibration coefficient CT = Tpt / F has to be previously established, which demands the knowledge of the transmissivity Tpt evaluated in the pumping test. The transmissivity can then be calculated at any other site of the same aquifer using the relation Tmrs = C TF . The CT values reported suggest a certain relationship with the lithology, but with a great dispersion and contradictory results. MRS surveys carried out in alluvial aquifers in Spain have shown that the value of CT evaluated at one site may not be valid at another place of the same aquifer, because of the great heterogeneity of this kind of geological environment. The demand of a pumping test at each site where a MRS is measured invalidates the method actually used for MRS transmissivity evaluation. More than 50 MRS have been used to propose a new methodology. The aquifers visited cover a great range of transmissivities (from 2 × 10 - 6 to 9 × 10 - 3 m 2/s). The MRS signal amplitude varies between 20 and 1400 nV, the signal/noise ratio is in the range from 0.6 to 42, and the value of the decay time constant varies from 200 to 800 ms. It has been demonstrated that when the transmissivity increases, the value of F decreases, and CT increases, except for certain groups of MRS taken at the same aquifer or part of one aquifer, for which F increases with Tpt, keeping CT constant. A function CT( F) of the type CT = mF- n has been obtained that allows the transmissivity evaluation without the need of Tpt. Considering that both values of

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

    USGS Publications Warehouse

    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.

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

    PubMed

    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.

  18. Water levels and water quality in the Mississippi River Valley alluvial aquifer in eastern Arkansas, 2012

    USGS Publications Warehouse

    Schrader, Tony P.

    2015-01-01

    Water samples were collected in the summer of 2012 from142 wells completed in the alluvial aquifer and measured onsite for specific conductance, temperature, and pH. Samples were collected from 94 wells for dissolved chloride analysis. Specific conductance ranged from 91 microsiemens per centimeter at 25 degrees Celsius (μS/cm at 25 °C) in Drew County to 984 μS/cm at 25 °C in Monroe County. The mean specific conductance was 547 μS/cm at 25 °C. Temperature ranged from 18.1 degrees Celsius (°C) in Crittenden County to 22.4 °C in Prairie County. The mean temperature was 22.1 °C. The pH ranged from 8.3 in Randolph County to 6.2 in Drew County and had a median of 7.3. Dissolved chloride concentrations ranged from 3.34 milligrams per liter (mg/L) in Randolph County to 182 mg/L in Lincoln County. The mean chloride concentration was 27.6 mg/L.

  19. Colloid-Associated Phosphorus Transport in Heterogeneous Alluvial Gravel Aquifer Media

    NASA Astrophysics Data System (ADS)

    Lafogler, M.; Pang, L.; McGill, E.; Baumann, T.; Close, M.

    2012-04-01

    Phosphorus is a fertilizer and commonly present in groundwater aquifers. Higher concentrations of phosphorus can lead to subsurface eutrophication and aid microbial growth. In former studies phosphorus was considered to be immobile. Recently, it was reported that phosphorus can be mobilized in the presence of colloids. In this study the impact of colloid-associated phosphorus transport is investigated in a heterogeneous porous medium using inorganic colloids (Kaolinite, Goethite) and E. coli bacteria to get a better understanding of phosphorus transport in aquifer media. A 2 m column was filled with heterogeneous alluvial gravel aquifer material from the Canterbury Plains/New Zealand with a grain size in the range of 2-40 mm. Injected solutions contained a conservative tracer (Bromide), phosphate, and either Kaolinite, Goethite, or E. coli bacteria. Eight experiments were conducted at flow rates of 20 m/day and 40 m/day, respectively. The effluent of the column was collected and analyzed. To distinguish dissolved and colloid associated phosphorous, unfiltered and filtered samples were compared. As recovery rates for the conservative tracer bromide we observed full recovery at the column effluent. For total phosphorus varying recovery rates were found depending on the type of colloid that was present in the solution. Together with Kaolinite we observed recovery rates of phosphorous of 42.5% at low flow conditions and 69.3% at high flow conditions. Together with Goethite we found recovery rates of 22.3% at low flow conditions and 57.6% at high flow conditions. With E. coli bacteria we documented recovery rates of 80.7% at low flow conditions and 61.0% at high flow conditions. For dissolved phosphorus the observed recovery rates were in general higher between 73.4% and 92.3%. The breakthrough curves showed that a significant fraction of mobile phosphorus was attached to colloids. At low flow conditions this fraction was higher than at high flow conditions. For

  20. River-aquifer interactions and their relationship to stygofauna assemblages: a case study of the Gwydir River alluvial aquifer (New South Wales, Australia).

    PubMed

    Menció, A; Korbel, K L; Hose, G C

    2014-05-01

    In contrast to surface water ecosystems, groundwater ecosystems are usually considered to have relatively stable conditions and physically inert environments. However, many groundwater ecosystems undergo substantial changes through space and time, related to fluxes in groundwater flow, exchange and nutrient imports. In this study we used hydrochemical data to: 1) determine the different hydrogeological conditions in an alluvial system, the shallow Gwydir River alluvial aquifer (located in Northern New South Wales, Australia); and 2) analyze the relationship between hydrochemical conditions and the composition of stygofauna assemblages in the aquifer. Using hydrochemical modeling and multivariate analyses, four main hydrogeological situations were defined as occurring in the aquifer. Bores were classified as having either a high, low or no influence from or exchange with the river. The latter group was further subdivided into those of low and high salinity. Further analysis combining the biological and hydrochemical data identified two main groups of samples. The first group was composed mainly of samples related to the aquifer groundwater which had higher richness and abundance of fauna compared to samples in the second group which was comprised of samples affected by stream water leakage and samples related to the highest salinities. These results suggest that more stable conditions (mainly related to steadier groundwater head levels) and lower nitrate concentrations promoted a more diverse and abundant stygofauna community.

  1. Characterization of Natural Organic Matter in Alluvial Aquifer Sediments: Approaches and Implications for Reactivity

    NASA Astrophysics Data System (ADS)

    Fox, P. M.; Nico, P. S.; Hao, Z.; Gilbert, B.; Tfaily, M. M.; Devadoss, J.

    2015-12-01

    Sediment-associated natural organic matter (NOM) is an extremely complex assemblage of organic molecules with a wide range of sizes, functional groups, and structures, which is intricately associated with mineral particles. The chemical nature of NOM may control its' reactivity towards metals, minerals, enzymes, and bacteria. Organic carbon concentrations in subsurface sediments are typically much lower than in surface soils, posing a distinct challenge for characterization. In this study, we investigated NOM associated with shallow alluvial aquifer sediments in a floodplain of the Colorado River. Total organic carbon (TOC) contents in these subsurface sediments are typically around 0.1%, but can range from 0.03% up to approximately 1.5%. Even at the typical TOC values of 0.1%, the mass of sediment-associated OC is approximately 5000 times higher than the mass of dissolved OC, representing a large pool of carbon that may potentially be mobilized or degraded under changing environmental conditions. Sediment-associated OC is much older than both the depositional age of the alluvial sediments and dissolved OC in the groundwater, indicating that the vast majority of NOM was sequestered by the sediment long before it was deposited in the floodplain. We have characterized the sediment-bound NOM from two locations within the floodplain with differing physical and geochemical properties. One location has relatively low organic carbon (<0.2%) and is considered suboxic [dissolved oxygen is low or absent, but no dissolved Fe(II) observed], while the other is a naturally reducing zone with higher organic carbon (0.2-1.5%) and Fe(II)-reducing conditions. An extraction scheme was developed using a combination of sequential extraction [water and sodium pyrophosphate (pH 10)] and purification in order to isolate different fractions of sediment-associated NOM. Analysis of these different NOM fractions was then carried out by FTIR and ESI-FTICR-MS to allow for comparison of NOM

  2. Groundwater response to serial stream stage fluctuations in shallow unconfined alluvial aquifers along a regulated stream (West Virginia, USA)

    NASA Astrophysics Data System (ADS)

    Maharjan, Madan; Donovan, Joseph J.

    2016-12-01

    Groundwater response to stream stage fluctuations was studied in two unconfined alluvial aquifers using a year-long time series of stream stages from two pools along a regulated stream in West Virginia, USA. The purpose was to analyze spatial and temporal variations in groundwater/surface-water interaction and to estimate induced infiltration rate and cumulative bank storage during an annual cycle of stream stage fluctuation. A convolution-integral method was used to simulate aquifer head at different distances from the stream caused by stream stage fluctuations and to estimate fluxes across the stream-aquifer boundary. Aquifer diffusivities were estimated by wiggle-matching time and amplitude of modeled response to multiple observed storm events. The peak lag time between observed stream and aquifer stage peaks ranged between 14 and 95 hour. Transient modeled diffusivity ranged from 1,000 to 7,500 m2/day and deviated from the measured and calculated single-peak stage-ratio diffusivity by 14-82 %. Stream stage fluctuation displayed more primary control over groundwater levels than recharge, especially during high-flow periods. Dam operations locally altered groundwater flow paths and velocity. The aquifer is more prone to surface-water control in the upper reaches of the pools where stream stage fluctuations are more pronounced than in the lower reaches. This method could be a useful tool for quick assessment of induced infiltration rate and bank storage related to contamination investigations or well-field management.

  3. Hydrogeology of the Susquehanna River valley-fill aquifer system and adjacent areas in eastern Broome and southeastern Chenango Counties, New York

    USGS Publications Warehouse

    Heisig, Paul M.

    2012-01-01

    The hydrogeology of the valley-fill aquifer system along a 32-mile reach of the Susquehanna River valley and adjacent areas was evaluated in eastern Broome and southeastern Chenango Counties, New York. The surficial geology, inferred ice-marginal positions, and distribution of stratified-drift aquifers were mapped from existing data. Ice-marginal positions, which represent pauses in the retreat of glacial ice from the region, favored the accumulation of coarse-grained deposits whereas more steady or rapid ice retreat between these positions favored deposition of fine-grained lacustrine deposits with limited coarse-grained deposits at depth. Unconfined aquifers with thick saturated coarse-grained deposits are the most favorable settings for water-resource development, and three several-mile-long sections of valley were identified (mostly in Broome County) as potentially favorable: (1) the southernmost valley section, which extends from the New York–Pennsylvania border to about 1 mile north of South Windsor, (2) the valley section that rounds the west side of the umlaufberg (an isolated bedrock hill within a valley) north of Windsor, and (3) the east–west valley section at the Broome County–Chenango County border from Nineveh to East of Bettsburg (including the lower reach of the Cornell Brook valley). Fine-grained lacustrine deposits form extensive confining units between the unconfined areas, and the water-resource potential of confined aquifers is largely untested. Recharge, or replenishment, of these aquifers is dependent not only on infiltration of precipitation directly on unconfined aquifers, but perhaps more so from precipitation that falls in adjacent upland areas. Surface runoff and shallow groundwater from the valley walls flow downslope and recharge valley aquifers. Tributary streams that drain upland areas lose flow as they enter main valleys on permeable alluvial fans. This infiltrating water also recharges valley aquifers. Current (2012) use of

  4. The role of the uncertainty in assessing future scenarios of water shortage in alluvial aquifers

    NASA Astrophysics Data System (ADS)

    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

  5. Land use effects in groundwater composition of an alluvial aquifer (Trussu River, Brazil) by multivariate techniques.

    PubMed

    de Andrade, Eunice Maia; Palácio, Helba Araújo Queiroz; Souza, Ivam Holanda; de Oliveira Leão, Raimundo Alípio; Guerreiro, Maria João

    2008-02-01

    Multivariate statistical techniques, cluster analysis (CA) and factor analysis/principal component analysis (FA/PCA), were applied to analyze the similarities or dissimilarities among the sampling sites to identify spatial and temporal variations in water quality and sources of contamination (natural and anthropogenic). The aquifer under study is supplied by the Trussu River, which has a general direction from west to east, within Iguatu County, Ceará, Brazil. Groundwater samples were collected in four shallow wells, located at the Trussu River alluvial, from October 2002 to February 2004. The samples were analyzed for 13 parameters: pH, electrical conductivity (EC), Na, Ca, Mg, K, Cl, HCO(3), PO(4), NH(4)-N, NO(3)-N, SO(4), and sodium adsorption ratio (SAR). Two zones were very well differentiated based on cluster analysis results, and implied a relation to geographic position and time variation. One zone called UL-upland region-corresponds to upland of studied area, used mainly for irrigation and livestock activities. The other zone called DL-downland region-corresponds to the region downstream and is occupied by human settlements. These results may be used to reduce the number of samples analyzed both in space and time, without too much loss of information. Three major independent factors that define water quality in the UL region and four in DL region were identified in the PCA. At both regions, rotated component (RC) loadings identified that the variables responsible for water quality composition are mainly related to soluble salts variables (natural process) and nutrients (high loads of NO(3)-N, NH(4)-N), expressing anthropogenic activities. RC also revealed that hydrochemical processes were the major factors responsible for water quality.

  6. A combined hydrochemical - isotopic approach for assessing the regional pollution of an alluvial aquifer in a urbanized environment

    NASA Astrophysics Data System (ADS)

    Gesels, Julie; Orban, Philippe; Popescu, Cristina; Knöller, Kay; Brouyère, Serge

    2014-05-01

    The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium with different types of contaminants, in particular inorganics such as sulfate, nitrate and ammonium. The sources of those contaminants are numerous: brownfields, urban waste water, subsurface acid mine drainage from former coal mines, atmospheric deposits related to pollutants emissions in the atmosphere... Sulfate, nitrate and ammonium are both typical pollutants of the aquifer and tracers of the possible pollution sources. According to the European legislation on water, groundwater resources should reach a good quality status before 2015. However, an exemption can be obtained if it may be unfeasible or unreasonably expensive to achieve good status. In this case, groundwater quality objectives and management plans can be adapted to these specific conditions. To obtain such an exemption for the Meuse alluvial aquifer, it is required to demonstrate that the poor qualitative status is caused by acid mine drainage, or by widespread historical atmospheric deposition from industries, and not by recent anthropogenic contamination from the urban and industrial context. In this context, a detailed hydrogeochemical characterization of groundwater has been performed, with the aim of determining the origin of the inorganic contaminations and the main processes contributing to poor groundwater quality. A large hydrochemical sampling campaign was performed, based on 71 selected representative sampling locations, to better characterize the different vectors (end-members) of contamination of the alluvial aquifer and their respective contribution to groundwater contamination in the area. Groundwater samples were collected and analyzed for major and minor compounds and metallic trace elements. The analyses also include stable isotopes in water, sulfate, nitrate, ammonium, boron and strontium. Different hydrogeochemical approaches are combined to

  7. Using 3D geological modelling and geochemical mixing models to characterise alluvial aquifer recharge sources in the upper Condamine River catchment, Queensland, Australia.

    PubMed

    Martinez, Jorge L; Raiber, Matthias; Cendón, Dioni I

    2017-01-01

    The influence of mountain front recharge on the water balance of alluvial valley aquifers located in upland catchments of the Condamine River basin in Queensland, Australia, is investigated through the development of an integrated hydrogeological framework. A combination of three-dimensional (3D) geological modelling, hydraulic gradient maps, multivariate statistical analyses and hydrochemical mixing calculations is proposed for the identification of hydrochemical end-members and quantification of the relative contributions of each end-member to alluvial aquifer recharge. The recognised end-members correspond to diffuse recharge and lateral groundwater inflows from three hydrostratigraphic units directly connected to the alluvial aquifer. This approach allows mapping zones of potential inter-aquifer connectivity and areas of groundwater mixing between underlying units and the alluvium. Mixing calculations using samples collected under baseflow conditions reveal that lateral contribution from a regional volcanic aquifer system represents the majority (41%) of inflows to the alluvial aquifer. Diffuse recharge contribution (35%) and inflow from two sedimentary bedrock hydrostratigraphic units (collectively 24%) comprise the remainder of major recharge sources. A detailed geochemical assessment of alluvial groundwater evolution along a selected flowpath of a representative subcatchment of the Condamine River basin confirms mixing as a key process responsible for observed spatial variations in hydrochemistry. Dissolution of basalt-related minerals and dolomite, CO2 uptake, ion-exchange, precipitation of clay minerals, and evapotranspiration further contribute to the hydrochemical evolution of groundwater in the upland alluvial aquifer. This study highlights the benefits of undertaking an integrated approach that combines multiple independent lines of evidence. The proposed methods can be applied to investigate processes associated with inter-aquifer mixing, including

  8. Integrated characterization of groundwater contamination in an alluvial system. Case study of Allier alluvial aquifer (Massif Central, France).

    NASA Astrophysics Data System (ADS)

    Mohammed, Nabaz; Celle-Jeanton, Hélène; Batisson, Isabelle; Bardot, Corinne; Colombet, Jonathan; Huneau, Frédéric; Le Coustumer, Philippe; Clauzet, Marie-Laure; Lavastre, Véronique

    2013-04-01

    Hydrogeology is an intrinsically multi-disciplinary field because of the critical role water plays in both human health and natural ecosystems. The NAA (Nappe Alluviale de l'Allier) project proposes an integrated research (hydrodynamic, hydrochemistry and biology) on the shallow aquifer of the Allier River (one of the main tributaries of the Loire River). This aquifer plays an important role in the regional water supply for it represents more than 60% of the total water abstraction. As an example, the sampling site, located near the city of Clermont-Ferrand (France) constitutes the major source of drinking water supply for more than 100 000 inhabitants and then plays a major role on the local socio-economy. A biweekly following sampling, that concerns hydrodynamical parameters, major ions and isotopes (oxygen-18, deuterium and carbon-13), has been achieved during two years on 2 rivers, 1 pond, 2 springs and 17 boreholes with the aim of defining the functioning of the aquifer in terms of quality and quantity of the water resources and then on the main processes that governs hydrodynamic and hydrochemistry. Preliminary results allowed discriminating different origins of groundwater with a part due to surface waters/groundwater interactions and a secondary origin that implies water circulating from the surrounding hills. A monthly following sampling of pesticides, pharmaceuticals and traces ions provides information on contaminants sources. In parallel, the dynamics of the microbial communities (bacteria, pico-cyanobacteria and pico-eukaryotes) was followed by flow cytometer. The bacterial diversity has been measured through PCR-DGGE analysis in order to evaluate the impact of the occurrence of contaminants.

  9. Transport of suspended solids from a karstic to an alluvial aquifer: The role of the karst/alluvium interface

    USGS Publications Warehouse

    Massei, N.; Lacroix, M.; Wang, H.Q.; Mahler, B.J.; Dupont, J.P.

    2002-01-01

    This study focuses on the coupled transport of dissolved constituents and particulates, from their infiltration on a karst plateau to their discharge from a karst spring and their arrival at a well in an alluvial plain. Particulate markers were identified and the transport of solids was characterised in situ in porous and karstic media, based on particle size analyses, SEM, and traces. Transport from the sinkhole to the spring appeared to be dominated by flow through karst: particulate transport was apparently conservative between the two sites, and there was little difference in the overall character of the particle size distribution of the particulates infiltrating the sinkhole and of those discharging from the spring. Qualitatively, the mineralogy of the infiltrating and discharging material was similar, although at the spring an autochthonous contribution from the aquifer was noted (chalk particles eroded from the parent rock by weathering). In contrast, transport between the spring and the well appears to be affected by the overlying alluvium: particles in the water from the well, showed evidence of considerable size-sorting. Additionally, SEM images of the well samples showed the presence of particles originating from the overlying alluvial system; these particles were not found in samples from the sinkhole or the spring. The differences between the particulates discharging from the spring and the well indicate that the water pumped from the alluvial plain is coming from the karst aquifer via the very transmissive, complex geologic interface between the underlying chalk formation and the gravel at the base of the overlying alluvial system. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Geohydrology, water quality, and preliminary simulations of ground-water flow of the alluvial aquifer in the Upper Black Squirrel Creek basin, El Paso County, Colorado

    USGS Publications Warehouse

    Buckles, D.R.; Watts, K.R.

    1988-01-01

    The upper Black Squirrel Creek basin in eastern El Paso County, Colorado, is underlain by an alluvial aquifer and four bedrock aquifers. Groundwater pumpage from the alluvial aquifer has increased since the mid-1950's, and water level declines have been substantial; the bedrock aquifers virtually are undeveloped. Groundwater pumpage for domestic, stock, agricultural, and municipal uses have exceeded recharge for the past 25 years. The present extent of the effect of pumpage on the alluvial aquifer was evaluated, and a groundwater flow model was used to simulate the future effect of continued pumpage on the aquifer. Measured water level declines from 1974 through 1984 were as much as 30 ft in an area north of Ellicott, Colorado. On the basis of the simulations, water level declines from October 1984 to April 1999 north of Ellicott might be as much as 20 to 30 ft and as much as 1 to 10 ft in most of the aquifer. The groundwater flow models provided a means of evaluating the importance of groundwater evapotranspiration at various stages of aquifer development. Simulated groundwater evapotranspiration was about 43% of the outflow from the aquifer during predevelopment stages but was less than 3% of the outflow from the aquifer during late-development stages. Analyses of 36 groundwater samples collected during 1984 indicated that concentrations of dissolved nitrite plus nitrate as nitrogen generally were large. Samples from 5 of the 36 wells had concentrations of dissolved nitrite plus nitrate as nitrogen that exceeded drinking water standards. Water from the alluvial aquifer generally is of suitable quality for most uses. (USGS)

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

    NASA Astrophysics Data System (ADS)

    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

  12. Near-decadal changes in nitrate and pesticide concentrations in the South Platte River alluvial aquifer, 1993-2004

    USGS Publications Warehouse

    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. Effects of land use on water quality of the Fountain Creek alluvial aquifer, east-central Colorado

    USGS Publications Warehouse

    Chafin, Daniel T.

    1996-01-01

    Water-quality data were collected from the Fountain Creek alluvial aquifer in 1988 and 1989 as part of the Toxic-Waste Ground-Water Contamination Program. These data indicate that dissolved solids, most major ions, fluoride, ammonium, boron, lithium, selenium, and strontium were more concentrated in the agricultural land-use area than in the upgradient urban land-use area. Nitrate and phosphate had significantly larger concentrations, and volatile organic compounds had significantly greater detection frequencies in the urban land-use area.

  14. Availability of water from the alluvial aquifer in part of the Green River Valley, King County, Washington

    USGS Publications Warehouse

    Lum, W. E.; Alvord, R.C.; Drost, B.W.

    1984-01-01

    The Muckleshoot Indian Tribe plans (1982) to build a fish hatchery in part of a 1.56-square-mile area in the Green River valley, Washington, and use groundwater to operate it. Groundwater data were collected in the area and used in a U.S. Geological Survey two-dimensional groundwater-flow model calibrated to simulate the groundwater-flow system in the study area. Measured water levels in the alluvial aquifer were simulated to within 1 foot at 7 of 12 observation wells, and within 2 feet at all 12 wells. When pumping from the aquifer was simulated with the model, it was found that all water pumped from wells was derived from induced leakage from the Green River into the alluvium and reduced leakage through the alluvium to the Green River. Pumping from the alluvium may also reduce the flow of a tributary to the Green River. (USGS)

  15. Drinking Water Quality Criterion - Based site Selection of Aquifer Storage and Recovery Scheme in Chou-Shui River Alluvial Fan

    NASA Astrophysics Data System (ADS)

    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.

  16. Nitrate probability mapping in the northern aquifer alluvial system of the river Tagus (Portugal) using Disjunctive Kriging.

    PubMed

    Mendes, Maria Paula; Ribeiro, Luís

    2010-02-01

    The Water Framework Directive and its daughter directives recognize the urgent need to adopt specific measures against the contamination of water by individual pollutants or a group of pollutants that present a significant risk to the quality of water. Probability maps showing that the nitrate concentrations exceed a legal threshold value in any location of the aquifer are used to assess risk of groundwater quality degradation from intensive agricultural activity in aquifers. In this paper we use Disjunctive Kriging to map the probability that the Nitrates Directive limit (91/676/EEC) is exceeded for the Nitrate Vulnerable Zone of the River Tagus alluvium aquifer. The Tagus alluvial aquifer system belongs to one of the most productive hydrogeological unit of continental Portugal and it is used to irrigate crops. Several groundwater monitoring campaigns were carried out from 2004 to 2006 according to the summer crops cycle. The study reveals more areas on the west bank with higher probabilities of contamination by nitrates (nitrate concentration values above 50mg/L) than on the east bank. The analysis of synthetic temporal probability map shows the areas where there is an increase of nitrates concentration during the summers.

  17. Over-extraction from shallow bedrock versus deep alluvial aquifers: Reliability versus sustainability considerations for India's groundwater irrigation

    NASA Astrophysics Data System (ADS)

    Fishman, Ram Mukul; Siegfried, Tobias; Raj, Pradeep; Modi, Vijay; Lall, Upmanu

    2011-06-01

    The excessive exploitation of groundwater aquifers is emerging as a worldwide problem, but it is nowhere as dramatic and consequential as it is in India, the world's largest consumer, where hundreds of millions of people depend on it. Usually the problem is framed in terms of a long-term decline in water tables and its consequence for extraction costs, resource depletion, and the sustainability of irrigated agriculture. Here a comparative analysis is provided of coupled groundwater, energy, and irrigation dynamics in two groundwater intensive regions in India that differ in their underlying hydrogeology—the Indian Punjab with its deep alluvial aquifers and the Telangana region in south-central India with its shallow hard rock aquifers. Using a simple modeling framework and piezometric and agricultural time series, we show that in shallow aquifers the sense in which extraction is excessive is different, and is related to the short-term reliability of water supply rather than long-term sustainability. This has important repercussions for irrigated agricultural economies.

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

    DOE PAGES

    Zhu, Lin; Dai, Zhenxue; Gong, Huili; ...

    2015-06-12

    Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This study 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 anmore » 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 into three sediment zones. In each zone, the explicit mathematical formulations of the transition probability models are constructed with optimized different integral scales and volumetric proportions. The hydrofacies distributions in the three zones are simulated sequentially by the multi-zone transition probability-based indicator simulations. Finally, the result of this study provides the heterogeneous structure of the alluvial fan for further study of flow and transport simulations.« less

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

    SciTech Connect

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

    2015-06-12

    Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This study 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 into three sediment zones. In each zone, the explicit mathematical formulations of the transition probability models are constructed with optimized different integral scales and volumetric proportions. The hydrofacies distributions in the three zones are simulated sequentially by the multi-zone transition probability-based indicator simulations. Finally, the result of this study provides the heterogeneous structure of the alluvial fan for further study of flow and transport simulations.

  20. Reconnaissance evaluation of contamination in the alluvial aquifer in the East Poplar oil field, Roosevelt County, Montana

    USGS Publications Warehouse

    Levings, G.W.

    1984-01-01

    Water moving from north to south in the alluvial aquifer of the Poplar River valley becomes contaminated with sodium chloride in the area underlain by the East Poplar oil fields. Four types of ground water were identified in the study area. Type 1 is sodium bicarbonate water. Type 2 is sodium chloride water with varying quantities of calcium and magnesium. Type 3 water contains sodium and chloride in significantly larger concentrations than Type 2. Type 4 water is the brine being injected into brine-disposal wells. Contamination of the alluvial aquifer is indicated by a brine-freshwater interface in the alluvium, by downstream increase in chloride concentration of the Poplar River, and by downstream change in water type of the Poplar River. Contamination also may be indicated by the distribution of iron and manganese concentrations in water from wells near a brine-disposal well. Possible sources of sodium chloride contamination in the alluvium are brine-disposal wells, pipelines, and storage or evaporation pits. The contamination can occur from leaks in the casing of disposal wells or in pipelines caused by the corrosive nature of the brine or from storage or evaporation pits that have been improperly sealed or have sustained tears in the sealing material. (USGS)

  1. Simulation of interaction between ground water in an alluvial aquifer and surface water in a large braided river

    USGS Publications Warehouse

    Leake, S.A.; Lilly, M.R.

    1995-01-01

    The Fairbanks, Alaska, area has many contaminated sites in a shallow alluvial aquifer. A ground-water flow model is being developed using the MODFLOW finite-difference ground-water flow model program with the River Package. The modeled area is discretized in the horizontal dimensions into 118 rows and 158 columns of approximately 150-meter square cells. The fine grid spacing has the advantage of providing needed detail at the contaminated sites and surface-water features that bound the aquifer. However, the fine spacing of cells adds difficulty to simulating interaction between the aquifer and the large, braided Tanana River. In particular, the assignment of a river head is difficult if cells are much smaller than the river width. This was solved by developing a procedure for interpolating and extrapolating river head using a river distance function. Another problem is that future transient simulations would require excessive numbers of input records using the current version of the River Package. The proposed solution to this problem is to modify the River Package to linearly interpolate river head for time steps within each stress period, thereby reducing the number of stress periods required.

  2. The quality of our Nation's waters: water quality in the Mississippi embayment-Texas coastal uplands aquifer system and Mississippi River Valley alluvial aquifer, south-central United States, 1994-2008

    USGS Publications Warehouse

    Kingsbury, James A.; Barlow, Jeannie R.; Katz, Brian G.; Welch, Heather L.; Tollett, Roland W.; Fahlquist, Lynne S.

    2015-01-01

    About 8 million people rely on groundwater from the Mississippi embayment—Texas coastal uplands aquifer system for drinking water. The Mississippi River Valley alluvial aquifer also provides drinking water for domestic use in rural areas but is of primary importance to the region as a source of water for irrigation. Irrigation withdrawals from this aquifer are among the largest in the Nation and play a key role in the economy of the area, where annual crop sales total more than $7 billion. The reliance of the region on both aquifers for drinking water and irrigation highlights the importance of long-term management to sustain the availability and quality of these resources.

  3. Distribution of polychlorinated biphenyls in the Housatonic River and adjacent aquifer, Massachusetts

    USGS Publications Warehouse

    Gay, Frederick B.; Frimpter, Michael H.

    1985-01-01

    Polychlorinated biphenyls (PCB's) are sorbed to the fine-grained stream-bottom sediments along the Housatonic River from Pittsfield, Massachusetts, southward to the Massachusetts-Connecticut boundary. The highest PCB concentrations, up to 140,000 micrograms per kilogram, were found in samples of bottom material from a reach of the river between Pittsfield and Woods Pond Dam in Lee, Massachusetts. Sediments in Woods Pond have been estimated to contain about 11,000 pounds of PCB's. Approximately 490 pounds per year of PCB's have also been estimated to move past the Housatonic River gaging station at Great Barrington. The distribution of hydraulic heads, water temperatures, and concentrations of dissolved oxygen, ammonia, nitrate, iron, and manganese in ground water shows that industrial water-supply wells in a sand and gravel aquifer adjacent to a stretch of the river called Woods Pond have been inducing ground-water recharge through the PCB-contaminated bottom sediments of the pond since late 1956. These data indicate that, at one location along the shore of the pond, the upper 40 feet of the aquifer contains water derived from induced infiltration. However, this induced recharge has not moved PCB's from the bottom sediments into a vertical section of the aquifer located 5 feet downgradient from the edge of Woods Pond. Samples taken at selected intervals in this section showed that no PCB's sorbed to the aquifer material or dissolved in the ground water within the detection limits of the chemical analyses.

  4. Monitoring and modeling of two alluvial aquifers in lower Nestos river basin, Northern Greece.

    PubMed

    Boskidis, Ioannis; Pisinaras, Vassilios; Petalas, Christos; Tsihrintzis, Vassilios A

    2012-01-01

    A groundwater monitoring and modeling program in two aquifers within the lower Nestos river basin in Northern Greece is presented. A monitoring network of 54 wells was developed in the two study areas, and groundwater level measurements and water quality sample analyses were conducted for a period of 2.5 years, from March 2007 to October 2009. The field data were used for the calibration and verification of the mathematical model MODFLOW in the two aquifers. The validated model was used to examine ten alternative management scenarios regarding groundwater abstraction in the two aquifers. The study showed that MODFLOW, if properly validated, is a useful and flexible tool in groundwater resources management.

  5. Groundwater ages in an alluvial aquifer: Confronting lumped parameter models (3H, CFCs and SF6) and numerical transport modeling.

    NASA Astrophysics Data System (ADS)

    Mouloudi, R.; Gourcy, L.; Kloppmann, W.; Violette, S.

    2012-04-01

    Groundwater age dating using tritium and dissolved gases was undertaken in an alluvial aquifer to determine groundwater transit time and flow rate as key parameters for assessing diffuse nitrate pollution.The studied site of about 260 km2 is crossed by the Ain River and bordered by the Rhône River which is the natural drain for the aquifer. It is mainly recharged by precipitation but also receives water from the Dombes plain (NW and W), intensively cultivated, and from the Bugey and Jura karstic mountains (NE and E part). In this study, we investigated the relevance of the gas-tracers CFCs and SF6 as age dating tools in alluvial shallow aquifers. The exponential model was chosen to conceptualize the alluvial aquifer recharge, 3H also used. Age-dating gave a mean recharge date of 5 to 18 years. CFCs, SF6 and 3H age estimation was confronted with the results of 2D transport modelling. Lumped parameter models were used to estimate the distribution of CFC and SF6 ages. Groundwater age is a measurable quantity, provided many assumptions. One of the underlying questions is the physical meaning of "ages" obtained by the lumped parameter models. Indeed, knowledge of an apparent age does not necessarily imply knowledge of the groundwater residence time. An independent approach of groundwater age determination is based on solving the solute transport problem. Few studies seek to compare the hydrodynamic and tracers approaches. This comparison aims to increase our hydrogeological understanding of the Ain alluvial plain and to better define " groundwater age" and its meanings. The hydrodynamic modelling was performed using MARTHE code (Thiéry, 2004). It was calibrated over a period of 8 years at a 10 days' time step. Results of the transitory regime calibration are satisfactory and allowed the use of this model for solute transport of 3H, CFCs and SF6. Different approaches are possible for the comparison of tracer and hydrodynamic models. The first is to reproduce the tracer

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

    NASA Astrophysics Data System (ADS)

    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

  7. Simulation of the transfer of organochlorine pollutants in an alluvial aquifer in an alpine valley: the case of tetrachloroethene

    NASA Astrophysics Data System (ADS)

    Kouamé, A. A.; Jaboyedoff, M.; Tacher, L.; Derron, M.-H.

    2012-04-01

    During a series of environmental analysis carried out in soil and groundwater in the Alpine Valley (Rhone valley Western Switzerland), were identified high levels of chlorinated solvents, particularly the tetrachloroethene. The leakage of this pollutant originates from industry. The geological substratum in this part of the valley is mainly composed of alluvial deposits and the deposit of a large rock avalanche. The sediments are composed of sandy silt, sandy clay, sand and gravel. The rock avalanche deposit which is the wall of the alluvial aquifer consists of fine materials, stones and large debris mainly of limestone. The investigations developed in this area have shown the presence of a contaminant plume of 60 m long and 35 m wide approximately. Thus the technique of venting / sparging was proposed as remediation measure. Despite the effectiveness of this technique, it turns out that there are still some pockets of contamination of groundwater in the area. In order to assess the potential pollution, a numerical modeling was developed by using the Visual Modflow software. The stages of this modeling are: • Selecting the parameters of the models; • Developing conceptual and numerical models; • Calibration and validation of the model; • Reproducing the observed concentrations; • Sensitivity analysis; • Making a parametric study to see at different stages the tetrachloroethene plume. The first results of the simulation show a slow leakage of the pollutant forming a pocket in the water flow direction.

  8. Evaluation of the processes affecting vertical water chemistry in an alluvial aquifer of Mankyeong Watershed, Korea, using multivariate statistical analyses

    NASA Astrophysics Data System (ADS)

    Choi, Byoung-Young; Kim, Hyeon-Jung; Kim, Kangjoo; Kim, Seok-Hwi; Jeong, Hwa-Jin; Park, Eungyu; Yun, Seong-Taek

    2008-03-01

    Vertical variations of redox chemistry and groundwater quality were investigated in an alluvial aquifer beneath an agricultural area, in which deep groundwaters are free of NO3, Fe, and Mn problems that are frequently encountered during the development of alluvial groundwaters. This study was performed to identify and evaluate vertical chemical processes attenuating these chemical species in the study area. For this study, the processes affecting groundwater chemistry were identified by factor analysis (FA) and the groundwater samples collected from six multilevel samplers were hierarchically classified into three different redox zones by cluster analysis (CA) based on the similarity of geochemical features. FA results indicated three major factors affecting the overall water chemistry: agricultural activities (factor 1), redox reactions (factor 2), and remnant seawater (factor 3). The groundwater quality in the study area was revealed to be controlled by a series of different redox reactions, resulting in different redox zones as a function of depth. It was also revealed that the low Fe and Mn levels in the groundwater of the deeper part are associated with sulfate reduction, which led to precipitation of Fe as iron sulfide and adsorption of Mn on it.

  9. An expert system supporting decision making process for sustainable groundwater use in main alluvial aquifers in Slovenia

    NASA Astrophysics Data System (ADS)

    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).

  10. Simulating land management options to reduce nitrate pollution in an agricultural watershed dominated by an alluvial aquifer.

    PubMed

    Cerro, Itsasne; Antigüedad, Iñaki; Srinavasan, Raghavan; Sauvage, Sabine; Volk, Martin; Sanchez-Perez, José Miguel

    2014-01-01

    The study area (Alegria watershed, Basque Country, Northern Spain) considered here is influenced by an important alluvial aquifer that plays a significant role in nitrate pollution from agricultural land use and management practices. Nitrates are transported primarily from the soil to the river through the alluvial aquifer. The agricultural activity covers 75% of the watershed and is located in a nitrate-vulnerable zone. The main objective of the study was to find land management options for water pollution abatement by using model systems. In a first step, the SWAT model was applied to simulate discharge and nitrate load in stream flow at the outlet of the catchment for the period between October 2009 and June 2011. The LOADEST program was used to estimate the daily nitrate load from measured nitrate concentration. We achieved satisfactory simulation results for discharge and nitrate loads at monthly and daily time steps. The results revealed clear variations in the seasons: higher nitrate loads were achieved for winter (20,000 kg mo NO-N), and lower nitrate loads were simulated for the summer (<1000 kg mo NO-N) period. In a second step, the calibrated model was used to evaluate the long-term effects of best management practices (BMPs) for a 50-yr period by maintaining actual agricultural practices, reducing fertilizer application by 20%, splitting applications (same total N but applied over the growing period), and reducing 20% of the applied fertilizer amount and splitting the fertilizer doses. The BMPs were evaluated on the basis of local experience and farmer interaction. Results showed that reducing fertilizer amounts by 20% could lead to a reduction of 50% of the number of days exceeding the nitrate concentration limit value (50 mg L) set by the European Water Framework Directive.

  11. Stream-floodwave propagation through the Great Bend alluvial aquifer, Kansas: Field measurements and numerical simulations

    USGS Publications Warehouse

    Sophocleous, M.A.

    1991-01-01

    The hypothesis is explored that groundwater-level rises in the Great Bend Prairie aquifer of Kansas are caused not only by water percolating downward through the soil but also by pressure pulses from stream flooding that propagate in a translatory motion through numerous high hydraulic diffusivity buried channels crossing the Great Bend Prairie aquifer in an approximately west to east direction. To validate this hypothesis, two transects of wells in a north-south and east-west orientation crossing and alongside some paleochannels in the area were instrumented with water-level-recording devices; streamflow data from all area streams were obtained from available stream-gaging stations. A theoretical approach was also developed to conceptualize numerically the stream-aquifer processes. The field data and numerical simulations provided support for the hypothesis. Thus, observation wells located along the shoulders or in between the inferred paleochannels show little or no fluctuations and no correlations with streamflow, whereas wells located along paleochannels show high water-level fluctuations and good correlation with the streamflows of the stream connected to the observation site by means of the paleochannels. The stream-aquifer numerical simulation results demonstrate that the larger the hydraulic diffusivity of the aquifer, the larger the extent of pressure pulse propagation and the faster the propagation speed. The conceptual simulation results indicate that long-distance propagation of stream floodwaves (of the order of tens of kilometers) through the Great Bend aquifer is indeed feasible with plausible stream and aquifer parameters. The sensitivity analysis results indicate that the extent and speed of pulse propagation is more sensitive to variations of stream roughness (Manning's coefficient) and stream channel slope than to any aquifer parameter. ?? 1991.

  12. Groundwater components in the alluvial aquifer of the alpine Rhone River valley, Bois de Finges area, Wallis Canton, Switzerland

    NASA Astrophysics Data System (ADS)

    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

  13. Fast ground-water mixing and basal recharge in an unconfined, alluvial aquifer, Konza LTER Site, Northeastern Kansas

    USGS Publications Warehouse

    Macpherson, G.L.; Sophocleous, M.

    2004-01-01

    pathways, (4) minuscule amounts of unsaturated-zone recharge, and (5) dissolved oxygen peaks in the saturated zone lagging water-level peaks. We postulate that rainfall enters fractures in bedrock adjacent to the floodplain. This recharge water moves rapidly through the fractured bedrock into the base of the floodplain aquifer. The recharge event through the bedrock causes a rapid rise in water level in the floodplain aquifer, and the chemistry of the deepest water in the floodplain aquifer changes at that time. The rising water also entrains slow-moving, nitrate-rich, unsaturated-zone water, altering the chemistry of water in the shallow part of the aquifer. Vertical chemical stratification in the aquifer is thus created by the change in water chemistry in the upper and lower parts of the saturated zone. As the water level begins to decline, the aquifer undergoes mixing that eventually results in homogeneous water chemistry. The rise in water level from the recharge event also displaces gas from the unsaturated zone that is then replaced as the water level declines following the recharge event. This new, oxygen-rich vadose-zone air equilibrates rapidly with saturated-zone water, resulting in a dissolved oxygen pulse in the ground water that peaks one-half to 2 months after the water-level peak. This oxygen pulse subsequently declines over a period of 2-6 months. ?? 2003 Elsevier B.V. All rights reserved.

  14. Lithology, hydrologic characteristics, and water quality of the Arkansas River Valley alluvial aquifer in the vicinity of Van Buren, Arkansas

    USGS Publications Warehouse

    Kresse, Timothy M.; Westerman, Drew A.; Hart, Rheannon M.

    2015-01-01

    The hydrologic and geochemical data gathered for this study provide a qualitative assessment of the potential of the Arkansas River Valley alluvial aquifer as a source of public water supply in the Van Buren area. Results indicate minimal influx of water from the Arkansas River, and recharge to the aquifer appears to be dominantly by infiltration of precipitation through overlying alluvium. If vertical wells are used as a source of public water supply, then several wells will have to be used in combination at relatively low pumping rates and placed in areas with a greater percent sand. Use of a horizontal well configuration near the river to increase production may depend on infiltration of river water to supplement water removed from storage, especially where areas of lower permeability sediments might be encountered within the surrounding alluvium. If a poor hydraulic connection exists between the river and the alluvium, as indicated by this study, then production will depend on ample precipitation and recharge throughout the year and groundwater storage sufficient to prevent declining water levels where pumping rates exceed recharge.

  15. Water quality in alluvial aquifers of the southern Rocky Mountains Physiographic Province, upper Colorado River basin, Colorado, 1997

    USGS Publications Warehouse

    Apodaca, Lori Estelle; Bails, Jeffrey B.

    2000-01-01

    Water-quality samples were collected in the summer of 1997 from 45 sites (43 wells and 2 springs) in selected alluvial aquifers throughout the Southern Rocky Mountains physiographic province of the Upper Colorado River Basin study unit as part of the U.S. Geological Survey National Water-Quality Assessment Program. The objective of this study was to assess the water-quality conditions in selected alluvial aquifers in the Southern Rocky Mountains physiographic province. Alluvial aquifers are productive aquifers in the Southern Rocky Mountains physiographic province and provide for easily developed wells. Water-quality samples were collected from areas where ground water is used predominantly for domestic or public water supply. Twenty-three of the 45 sites sampled were located in or near mining districts. No statistical differences were observed between the mining sites and sites not associated with mining activities for the majority of the constituents analyzed. Water samples were analyzed for major ions, nutrients, dissolved organic carbon, trace elements, radon-222, pesticides, volatile organic compounds, bacteria, and methylene blue active substances. In addition, field parameters consisting of water temperature, specific conductance, dissolved oxygen, pH, turbidity, and alkalinity were measured at all sites.Specific conductance for the ground-water sites ranged from 57 to 6,650 microsiemens per centimeter and had higher concentrations measured in areas such as the northwestern part of the study unit. Dissolved oxygen ranged from 0.1 to 6.0 mg/L (milligrams per liter) and had a median concentration of 2.9 mg/L. The pH field values ranged from 6.1 to 8.1; about 4 percent of the sites (2 of 45) had pH values outside the range of 6.5 to 8.5 and so did not meet the U.S. Environmental Protection Agency secondary maximum contaminant level standard for drinking water. About 5 percent (2 of 43) of the samples exceeded the U.S. Environmental Protection Agency recommended

  16. Computational and Experimental Simulations of Cr(VI) Remediation via In Situ Reduction in an Alluvial Aquifer at Hinkley, California

    NASA Astrophysics Data System (ADS)

    Bobb, C.; Miller, L. G.; Kent, D. B.; Maher, K.

    2015-12-01

    The accumulation of hexavalent chromium (Cr(VI)) in groundwater due to natural and human-induced processes poses a significant health threat as Cr(VI) is both a carcinogen and mutagen. Anthropogenic Cr(VI) contamination has compromised drinking water in the alluvial aquifer underlying the town of Hinkley, CA and extensive in-situ remediation (ISR) is underway to mitigate the threat to residents. ISR capitalizes on the redox sensitivity of chromium by using ethanol to reduce soluble, toxic, Cr(VI) to insoluble and non-hazardous Cr(III). However, the sequence of reduction reactions that occurs within the aquifer is not well understood. Therefore, we use computer-modeled and experimental redox titrations to examine how pH, oxygen supply, mineral surface chemistry, agitation, and microbial activity impact the reduction of Cr(VI) by ethanol. We further use experimental titrations to confirm the validity of our modeled results. Aqueous and gaseous phases are monitored throughout the experiment to track changes in pH, dissolved oxygen, CO2, Mn(II), Fe(II), and SO42-. Aqueous Fe(II) is a dominant control on Cr(VI) reduction; thus the cycling of Fe in the system must be considered. Our modeled results show that reductive dissolution of manganese oxides and Fe(III) (oxy)hydroxides increases pH, making sulfate reduction thermodynamically favorable. Simultaneous Fe(III) and sulfate reduction allows precipitation of iron sulfide minerals, limiting the available Fe(II) to reduce Cr(VI). Computational model results indicate that elevated organic buffer (HEPES, MOPS, EPPS) concentrations are required to maintain pH values below 8.8 where simultaneous reduction of Fe(III) and SO42- during ethanol oxidation becomes thermodynamically favorable. Microbial activity within the aquifer may also play a significant role in the transfer of electrons from ethanol to the terminal electron acceptors.

  17. Potentiometric Surface of the Alluvial Aquifer and Hydrologic Conditions in the Juana Diaz area, Puerto Rico, June 29 - July 1, 2005

    USGS Publications Warehouse

    Rodriguez, Jose M.; Santigo-Rivera, Luis; Gómez-Gómez, Fernando

    2006-01-01

    A synoptic survey of the hydrologic conditions in the Juana Diaz area, Puerto Rico, was conducted between June 29 and July 1, 2005, to define the spatial distribution of the potentiometric surface of the alluvial aquifer. The study area encompasses 21 square miles of the more extensive South Coastal Plain Alluvial Aquifer system and is bounded along the north by foothills of the Cordillera Central mountain chain, to the south by the Caribbean Sea, the east by the Rio Descalabrado and to the west by the Rio Inabon. Ground water in the Juana Diaz area is in the Quaternary-age alluvial deposits and the middle-Tertiary age Ponce Limestone and Juana Diaz Formation (Giusti, 1968). The hydraulic properties of the Ponce Limestone in the Juana Diaz area are unknown, and the Juana Diaz Formation is a unit of poor permeability due to its high clay content. Consequently, the Ponce Limestone and the Juana Diaz Formation are generally considered to be the base of the alluvial aquifer in the Juana Diaz area with ground-water flow occurring primarily within the alluvial deposits. The potentiometric-surface map of the alluvial aquifer was delineated using ground-water level measurements taken at existing wells. The water-level measurements were taken at wells that were either not pumping during the survey or were shut down for a brief period. In the latter case, a recovery period of 30 minutes was allowed for the drawdown in the wellbore to achieve a near static level position representative of the aquifer at the measurement point. Land-surface altitude from U.S. Geological Survey (USGS) 1:20,000 scale topographic maps (Playa de Ponce, Ponce, Rio Descalabrado, and Santa Isabel) were used to refer ground-water levels to mean sea level datum (National Geodetic Vertical Datum of 1929). In addition to the ground-water level measurements, the potentiometricsurface contours were delineated using hydrologic features, such as drainage ditches and saturated intermittent streams that were

  18. Effects of surface-water irrigation on sources, fluxes, and residence times of water, nitrate, and uranium in an alluvial aquifer

    USGS Publications Warehouse

    Böhlke, J.K.; Verstraeten, Ingrid M.; Kraemer, T.F.

    2007-01-01

    Effects of surface-water irrigation on an alluvial aquifer were evaluated using chemical and isotopic data including ??2H, ??18O, 3H, ??3He, Ar, Ne, N2, ??15N, and 234U/238U activity ratios in a transect of nested wells in the North Platte River valley in western Nebraska, USA. The data were used to evaluate sources and fluxes of H2O, NO3- and U, all of which were strongly affected by irrigated agriculture. Combined results indicate that the alluvial aquifer was dominated by irrigation water that had distinctive chemical and isotopic features that were inherited from the North Platte River or acquired from agricultural soils or recharge processes. Values of ??2H, ??18O, Ar and Ne indicate that most of the ground water in the alluvial aquifer was irrigation water that was derived from the North Platte River and distributed during the growing season. The irrigation water was identified by an evaporated isotopic signature that was acquired by the river in major upstream reservoirs in Wyoming, and by relatively warm gas-equilibration temperatures related to warm-season recharge. Apparent 3H-3He ages indicate that the ground water in the alluvium was stratified and mostly 3.0 m/a. Age gradients and NO3- concentrations indicate that recharge occurred by a combination of focused leakage from irrigation canals (rapid local recharge, low NO3-) and distributed infiltration beneath the irrigated agricultural fields (lower recharge, high NO3-). Large amounts of U with relatively low 234U/238U activity ratios were present in the alluvial aquifer as a result of irrigation with U-bearing river water, and minor amounts of U with higher 234U/238U activity ratios were added locally from basal and underlying volcanic-rich sediments. Distributions of NO3-, ?? 15 N [NO3-], dissolved gases, and ground-water ages indicate that NO3- concentrations increased and ?? 15 N [NO3-] values decreased in distributed recharge in the last few decades, possibly in relation to a documented increase in

  19. Joint Inversion of Hydrologic and Geophysical Data for Permeability Distribution of an Alluvial Aquifer

    DTIC Science & Technology

    2007-11-02

    electromagnetic soundings, and ground penetrating radar; (5) demonstrating a method for modeling hydrologic responses at a well with MODFLOW ; (6) generating...program developments in MODFLOW and MODFLOWP to facilitate modeling 3-D heterogeneous aquifer systems. Also, findings from this project were the

  20. Geochemical impacts of groundwater heat pump systems in an urban alluvial aquifer with evaporitic bedrock.

    PubMed

    Garrido Schneider, Eduardo A; García-Gil, Alejandro; Vázquez-Suñè, Enric; Sánchez-Navarro, José Á

    2016-02-15

    In the last decade, there has been an extensive use of shallow geothermal exploitations in urban environments. Although the thermal interference between exploitations has been recently studied, there is a lack of knowledge regarding the geochemical impacts of those systems on the aquifers where they are installed. Groundwater flow line scale and well-doublet scale research work has been conducted at city scale to quantify the geochemical interaction of shallow geothermal exploitations with the environment. A comprehensive analysis was conducted on data obtained from a monitoring network specifically designed to control and develop aquifer policies related to thermal management of the aquifer. The geochemical impacts were evaluated from a thermodynamic point of view by means of saturation index (SI) calculations with respect to the different mineral species considered in the system. The results obtained indicate limited geochemical interaction with the urban environment in most of the situations. However, there are some cases where the interaction of the groundwater heat pump installations with the evaporitic bedrock resulted in the total disablement of the exploitation system operation wells. The application of the tool proposed proved to be pragmatic in the evaluation of geochemical impacts. Injection of water into the aquifer can trigger an important bedrock gypsum and halite dissolution process that is partly responsible for scaling in well casing pipes and collapse of the terrain in the vicinity of injection wells.

  1. Early findings from artificial recharge efforts of the Mississippi River Valley Alluvial Aquifer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The long-term success and sustainability of agriculture in the Lower Mississippi River Basin will depend largely on water resources. Aquifer decline in the region has been documented since the 1980s and continues today. Artificial recharge is one possible tool that could help alleviate this declin...

  2. An integrated approach for aquifer vulnerability mapping using GIS and rough sets: study from an alluvial aquifer in North India

    NASA Astrophysics Data System (ADS)

    Khan, Arina; Khan, Haris Hasan; Umar, Rashid; Khan, Muneeb Hasan

    2014-06-01

    A modified DRASTIC model in a geographic information system (GIS) environment coupled with an information-analytic technique called `rough sets' is used to understand the aquifer vulnerability characteristics of a segment of the lower Kali watershed in western Uttar Pradesh, India. Since the region is a flat plain, topography (T) is removed as a potential control. Other parameters are the same as in DRASTIC, hence the new model is termed as DRASIC. The rough set technique is employed to provide insight into the relative vulnerabilities of different administrative units (blocks) within the study area. Using rough sets, three important factors are computed: strength, certainty and coverage. Strength indicates how the vulnerability characteristics vary in the entire area, certainty gives the relative fractions of low, medium and high vulnerability regions within a particular block, and coverage computes the percentage of a particular vulnerability state in each block. The purpose of the work is to demonstrate the utility of this integrated approach in classifying different administrative blocks in the study area according to their aquifer vulnerability characteristics. This approach is particularly useful for block-level planning and decision making for sustainable management of groundwater resources.

  3. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes.

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Shallow Alluvial Aquifer Ground Water System and Surface Water/Ground Water Interaction, Boulder Creek, Boulder, Colorado

    NASA Astrophysics Data System (ADS)

    Babcock, K. P.; Ge, S.; Crifasi, R. R.

    2006-12-01

    Water chemistry in Boulder Creek, Colorado, shows significant variation as the Creek flows through the City of Boulder [Barber et al., 2006]. This variation is partially due to ground water inputs, which are not quantitatively understood. The purpose of this study is (1) to understand ground water movement in a shallow alluvial aquifer system and (2) to assess surface water/ground water interaction. The study area, encompassing an area of 1 mi2, is located at the Sawhill and Walden Ponds area in Boulder. This area was reclaimed by the City of Boulder and Boulder County after gravel mining operations ceased in the 1970's. Consequently, ground water has filled in the numerous gravel pits allowing riparian vegetation regrowth and replanting. An integrated approach is used to examine the shallow ground water and surface water of the study area through field measurements, water table mapping, graphical data analysis, and numerical modeling. Collected field data suggest that lateral heterogeneity exists throughout the unconsolidated sediment. Alluvial hydraulic conductivities range from 1 to 24 ft/day and flow rates range from 0.01 to 2 ft/day. Preliminary data analysis suggests that ground water movement parallels surface topography and does not noticeably vary with season. Recharge via infiltrating precipitation is dependent on evapotranspiration (ET) demands and is influenced by preferential flow paths. During the growing season when ET demand exceeds precipitation rates, there is little recharge; however recharge occurs during cooler months when ET demand is insignificant. Preliminary data suggest that the Boulder Creek is gaining ground water as it traverses the study area. Stream flow influences the water table for distances up to 400 feet. The influence of stream flow is reflected in the zones relatively low total dissolved solids concentration. A modeling study is being conducted to synthesize aquifer test data, ground water levels, and stream flow data. The

  6. Distribution and variability of redox zones controlling spatial variability of arsenic in the Mississippi River Valley alluvial aquifer, southeastern Arkansas

    USGS Publications Warehouse

    Sharif, M.U.; Davis, R.K.; Steele, K.F.; Kim, B.; Hays, P.D.; Kresse, T.M.; Fazio, J.A.

    2008-01-01

    Twenty one of 118 irrigation water wells in the shallow (25-30??m thick) Mississippi River Valley alluvial aquifer in the Bayou Bartholomew watershed, southeastern Arkansas had arsenic (As) concentrations (< 0.5 to 77????g/L) exceeding 10????g/L. Sediment and groundwater samples were collected and analyzed from the sites of the highest, median, and lowest concentrations of As in groundwater in the alluvial aquifers located at Jefferson County, Arkansas. A traditional five-step sequential extraction was performed to differentiate the exchangeable, carbonate, amorphous Fe and Mn oxide, organic, and hot HNO3-leachable fraction of As and other compounds in sediments. The Chao reagent (0.25??M hydroxylamine hydrochloride in 0.25??M HCl) removes amorphous Fe and Mn oxides and oxyhydroxides (present as coatings on grains and amorphous minerals) by reductive dissolution and is a measure of reducible Fe and Mn in sediments. The hot HNO3 extraction removes mostly crystalline metal oxides and all other labile forms of As. Significant total As (20%) is complexed with amorphous Fe and Mn oxides in sediments. Arsenic abundance is not significant in carbonates or organic matter. Significant (40-70????g/kg) exchangeable As is only present at shallow depth (0-1??m below ground surface). Arsenic is positively correlated to Fe extracted by Chao reagent (r = 0.83) and hot HNO3 (r = 0.85). Arsenic extracted by Chao reagent decreases significantly with depth as compared to As extracted by hot HNO3. Fe (II)/Fe (the ratio of Fe concentration in the extracts of Chao reagent and hot HNO3) is positively correlated (r = 0.76) to As extracted from Chao reagent. Although Fe (II)/Fe increases with depth, the relative abundance of reducible Fe decreases noticeably with depth. The amount of reducible Fe, as well as As complexed to amorphous Fe and Mn oxides and oxyhydroxides decreases with depth. Possible explanations for the decrease in reducible Fe and its complexed As with depth include

  7. Surface complexation modeling for predicting solid phase arsenic concentrations in the sediments of the Mississippi River Valley alluvial aquifer, Arkansas, USA

    USGS Publications Warehouse

    Sharif, M.S.U.; Davis, R.K.; Steele, K.F.; Kim, B.; Hays, P.D.; Kresse, T.M.; Fazio, J.A.

    2011-01-01

    The potential health impact of As in drinking water supply systems in the Mississippi River Valley alluvial aquifer in the state of Arkansas, USA is significant. In this context it is important to understand the occurrence, distribution and mobilization of As in the Mississippi River Valley alluvial aquifer. Application of surface complexation models (SCMs) to predict the sorption behavior of As and hydrous Fe oxides (HFO) in the laboratory has increased in the last decade. However, the application of SCMs to predict the sorption of As in natural sediments has not often been reported, and such applications are greatly constrained by the lack of site-specific model parameters. Attempts have been made to use SCMs considering a component additivity (CA) approach which accounts for relative abundances of pure phases in natural sediments, followed by the addition of SCM parameters individually for each phase. Although few reliable and internally consistent sorption databases related to HFO exist, the use of SCMs using laboratory-derived sorption databases to predict the mobility of As in natural sediments has increased. This study is an attempt to evaluate the ability of the SCMs using the geochemical code PHREEQC to predict solid phase As in the sediments of the Mississippi River Valley alluvial aquifer in Arkansas. The SCM option of the double-layer model (DLM) was simulated using ferrihydrite and goethite as sorbents quantified from chemical extractions, calculated surface-site densities, published surface properties, and published laboratory-derived sorption constants for the sorbents. The model results are satisfactory for shallow wells (10.6. m below ground surface), where the redox condition is relatively oxic or mildly suboxic. However, for the deep alluvial aquifer (21-36.6. m below ground surface) where the redox condition is suboxic to anoxic, the model results are unsatisfactory. ?? 2011 Elsevier Ltd.

  8. Altitude of the water table in the alluvial and Wilcox aquifers in the vicinity of Richland and Tehuacana creeks and the Trinity River, Texas, December 1979

    USGS Publications Warehouse

    Garza, Sergio

    1980-01-01

    This map shows the altitude of the water table in the alluvial and Wilcox aquifers in the vicinity of Richland and Tehuacana Creeks and the Trinity River, Tex., in December 1979. The water-table contours were constructed on the basis of water-level control derived from an inventory of shallow wells in the area, topographic maps, and field locations of numerous small springs and seeps. (USGS)

  9. Use of borehole neutron logs to estimate moisture content in the unsaturated zone of an alluvial aquifer

    USGS Publications Warehouse

    Quinones-Aponte, Vicente; Carrasquillo, Ramon A.; Quinones, Ferdinand; Sanchez, A.V.; Smith, H.

    1986-01-01

    he neutron borehole logging tool was calibrated for the determination of moisture content in theunsaturated zone of an alluvial aquifer. A continuous core sample was collected to a depth of 15 ft from the unsaturated zone.Moisture content and other soil properties were determined by standard soil-laboratory techniques. The neutron logs profile was correlated to moisture content. The first correlation included all the data points within the unsaturated zone. A correlation coefficient of 0.72 was obtained. An inspection of the plotted data showed that points at the upper extreme of the fitted line departed significantly. A second correlation was tried eliminating data points 1, 3, and 5 which fell too low in the first trial. An almost perfect correlation coefficient of 0.99 was obtained for the data points that were included in the second trial. The criteria used to select the data points for the second correlation trial was that all these points also fell on the left most limit of the neutronprofile. The neutron logs profile, which is like a type of harmonic curve seems to be affected by an undefined factor. Analyzing the shape of the neutron profile it is inferred that hysteresis is the most probable phenomena that is affecting this moisture content profile. Although correlating neutron logs to moisture content is not a straight forward procedure, with an appropriate analysis, calibrated neutron logging tools can be used to determine the moisture content within the unsaturated zone of aquifers. Moisture content should be determined for calibration purposes at least at every foot of depth. Measurements of other elements or factors which may produce the harmonic curve effect might be included in further studies. 

  10. Geohydrology of the southwest alluvial basins regional aquifer- systems analysis, parts of Colorado, New Mexico, and Texas

    USGS Publications Warehouse

    Wilkins, D.W.

    1986-01-01

    The Southwest Alluvial Basins study is part of the National Regional Aquifer-Systems Analysis program. Twenty-two structural basins extend from the San Luis Basin in southern Colorado to the Presidio Basin in western Texas. Closed surface-water basins west of the Guadalupe Mountains and east of the Peloncillo Mountains are included in the study. The study area is bounded on the east by predominately Precambrian and Paleozoic rocks. Tertiary and Quaternary volcanics also are present. Tertiary and Quaternary volcanic rocks, and also Mesozoic rocks west of the Espanola and Albuquerque-Belen Basins, form the west boundary. The east and west boundary units converge at the north end of the study area to form the north boundary. The study area extends south to the international border between the United States and Mexico. The Santa Fe Group sediments of late Oligocene to middle Pleistocene age comprise the main aquifer in the area. Estimated maximum depths of sediments in the rift basins range from 8,000 ft in the Tularosa-Hueco Basin to 30,000 ft in the San Luis Basin. The average thickness of sediments in closed basins is about 4,000 ft. Santa Fe deposits are composed of layers of gravel, sand, silt, and clay interbedded with local volcanic lows of tuffs. Lacustrine deposits are more prevalent in the closed basins. Wells produce as much as 2,000 gal of water/min. Poteniometric-surface altitudes for 1971-82 indicate that water recharges in the highland areas around the basins and discharges in the center of valleys. Water generally flows from the east and west southward along the axis of the valleys. Groundwater quality for the region has been zoned into calcium sulfate, calcium chloride, magnesium sulfate, magnesium chloride; sodium sulfate, sodium chloride; sodium bicarbonate; and calcium bicarbonate, magnesium bicarbonate types. (USGS)

  11. Evaluating the Risks of Surface Spills Associated with Hydraulic Fracturing Activities to Groundwater Resources: a Modeling Study in the South Platte Alluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Kanno, C.; McLaughlin, M.; Blotevogel, J.; Benson, D. A.; Borch, T.; McCray, J. E.

    2015-12-01

    Hydraulic fracturing has revolutionized the U.S.'s energy portfolio by making shale reservoirs productive and commercially viable. However, the public is concerned that the chemical constituents in hydraulic fracturing fluid, produced water, or natural gas itself could potentially impact groundwater or adjacent streams. Here, we conduct fate and transport simulations of surface spills, the most likely contamination pathway to occur during oil and gas production operations, to evaluate whether or not these spills pose risks to groundwater quality. We focus on the South Platte Alluvial Aquifer, which is located in the greater Denver metro area and overlaps a zone of high-density oil and gas development. The purpose of this work is to assess the mobility and persistence of chemical contaminants (e.g. biocides, friction reducers, surfactants, hydrocarbons, etc.) —based on sorption to soil, degradation potential, co-contaminant interactions, and spill conditions—and to understand the site characteristics and hydrologic conditions that would make a particular location prone to groundwater quality degradation in the event of an accidental release. We propose a coupled analytical-numerical approach that could be duplicated by environmental consultants. Results suggest that risk of groundwater pollution, based on predicted concentration at the groundwater table, is low in most areas of the South Platte system for the contaminants investigated under common spill conditions. However, substantial risk may exist in certain areas where the groundwater table is shallow. In addition, transport of certain contaminants is influenced by interactions with other constituents in produced or stimulation fluids. By helping to identify locations in the Front Range of Colorado that are at low or high risk for groundwater contamination due to a surface spill, it is our hope that this work will aid in improving prevention, mitigation, and remediation practices so that decision-makers can

  12. Simulation of ground-water flow in the Cedar River alluvial aquifer flow system, Cedar Rapids, Iowa

    USGS Publications Warehouse

    Turco, Michael J.; Buchmiller, Robert C.

    2004-01-01

    Model results indicate that the primary sources of inflow to the modeled area are infiltration from the Cedar River (53.0 percent) and regional flow in the glacial and bedrock materials (34.1 percent). The primary sources of outflow from the modeled area are discharge to the Cedar River (45.4 percent) and pumpage (44.8 percent). Current steady-state pumping rates have increased the flow of water from the Cedar River to the alluvial aquifer by 43.8 cubic feet per second. Steady-state and transient hypothetical pumpage scenarios were used to show the relation between changes in pumpage and changes in infiltration of water from the Cedar River. Results indicate that more than 99 percent of the water discharging from municipal wells infiltrates from the Cedar River, that the time required for induced river recharge to equilibrate with municipal pumpage may be 150 days or more, and that ground-water availability in the Cedar Rapids area will not be significantly affected by doubling current pumpage as long as there is sufficient flow in the Cedar River to provide recharge.

  13. Stochastic Spectral Analysis for Characterizing Hydraulic Diffusivity in an Alluvial Fan Aquifer with River Stimulus

    NASA Astrophysics Data System (ADS)

    Wang, Y. L.; Zha, Y.; Yeh, T. C. J.; Wen, J. C.

    2015-12-01

    Estimation of subsurface hydraulic diffusivity was carried out to understand the characteristics of Zhuoshui River alluvial fan, Taiwan. The fan, an important agricultural and industrial region with high water demand, is located at middle Taiwan with an area of 1800 km2. The prior geo-investigations suggest that the main recharge region of the fan is at an apex along the river. The distribution of soil hydraulic diffusivity was estimated by fusing naturally recurring stimulus provided by river and groundwater head. Specifically, the variance and power spectrum provided by temporal and spatial change of groundwater head in response to river stage variations are analyzed to estimate hydraulic diffusivity distribution. It is found that the hydraulic diffusivity of the fan is at the range from 0.08 to 16 m2/s. The average hydraulic diffusivity at the apex, middle, and tail of the fan along the river is about 0.4, 0.6, and 1.0 m2/s, respectively.

  14. Simulated ground-water flow in the Hueco Bolson, an alluvial-basin aquifer system near El Paso, Texas

    USGS Publications Warehouse

    Heywood, Charles E.; Yager, Richard M.

    2003-01-01

    The neighboring cities of El Paso, Texas, and Ciudad Juarez, Chihuahua, Mexico, have historically relied on ground-water withdrawals from the Hueco Bolson, an alluvial-aquifer system, to supply water to their growing populations. By 1996, ground-water drawdown exceeded 60 meters in some areas under Ciudad Juarez and El Paso. A simulation of steady-state and transient ground-water flow in the Hueco Bolson in westernmost Texas, south-central New Mexico, and northern Chihuahua, Mexico, was developed using MODFLOW-96. The model is needed by El Paso Water Utilities to evaluate strategies for obtaining the most beneficial use of the Hueco Bolson aquifer system. The transient simulation represents a period of 100 years beginning in 1903 and ending in 2002. The period 1903 through 1968 was represented with 66 annual stress periods, and the period 1969 through 2002 was represented with 408 monthly stress periods. The ground-water flow model was calibrated using MODFLOWP and UCODE. Parameter values representing aquifer properties and boundary conditions were adjusted through nonlinear regression in a transient-state simulation with 96 annual time steps to produce a model that approximated (1) 4,352 water levels measured in 292 wells from 1912 to 1995, (2) three seepage-loss rates from a reach of the Rio Grande during periods from 1979 to 1981, (3) three seepage-loss rates from a reach of the Franklin Canal during periods from 1990 to 1992, and (4) 24 seepage rates into irrigation drains from 1961 to 1983. Once a calibrated model was obtained with MODFLOWP and UCODE, the optimal parameter set was used to create an equivalent MODFLOW-96 simulation with monthly temporal discretization to improve computations of seepage from the Rio Grande and to define the flow field for a chloride-transport simulation. Model boundary conditions were modified at appropriate times during the simulation to represent changes in well pumpage, drainage of agricultural fields, and channel

  15. Hydrology of the alluvial, buried channel, basal Pleistocene and Dakota aquifers in west-central Iowa

    USGS Publications Warehouse

    Runkle, D.L.

    1985-01-01

    The Dakota aquifer consists of the saturated sandstone and gravel units in the Dakota Formation. Isolated erosional remnants of the Dakota Formation form the caps of many bedrock ridges. The Dakota Formation is thickest where the bedrock surface is relatively high and flat, forming an ancient, buried, surface-water divide between southwest and southeast trending buried drainages in Audubon, Carroll, and Guthrie Counties. Sandstone thickness of as much as 150 feet exists in Guthrie County, but an average thickness of 30 feet is more common. Water from wells less than 200 feet deep generally is a calcium bicarbonate type and has an average dissolved-solids concentration of 650 milligrams per liter. Water from wells more than 200 feet deep generally is a calcium sulfate or sodium bicarbonate type and has an average dissolved-solids concentrations of 2,200 milligrams per liter.

  16. Determination of urban groundwater pollution in alluvial aquifer using linked process models considering urban water cycle

    NASA Astrophysics Data System (ADS)

    Vizintin, Goran; Souvent, Petra; Veselič, Miran; Cencur Curk, Barbara

    2009-10-01

    SummaryThis paper presents the results of the 5th FP project AISUWRS (Assessing and Improving the Sustainability of Urban Water Resources and Systems) which aimed to assess the impact of the urban water infrastructure to underlying or nearby aquifers with the urban water balance modelling approach - a chain of different models that handle with contaminant fluxes and the movement of contaminants from the urban infrastructure into the underlying aquifer. An existing urban water management model UVQ was linked to a model for sewer infiltration and exfiltration (NEIMO), as well as unsaturated zone models (SLeakI/POSI, UL_FLOW) with existing numerical groundwater models. The linked process models offer the prospect of better quantification of urban water balance and contaminant loads, including improved estimates of total recharge and its components in urban areas. Once the model framework has been set up for a selected city, it can easily be updated in the future and it can be used for other purposes like planning of local remediation measures in the vicinity of individual contaminant spillages. This paper describes the application and results of the urban water model chain for the city of Ljubljana, which is the capital of Slovenia. The results from this study suggest that residential land-uses in urban areas with thick unsaturated zone may have significantly smaller impact on the groundwater than agriculture or industry. This can be seen as a speculative understanding of the groundwater pollutions problems. In this respect, use of sustainable urban development systems like on-site infiltration of roof runoff and improved sewer control and standards could result in better groundwater quality.

  17. Biogeochemical constraints on the origin of methane in an alluvial aquifer: evidence for the upward migration of methane from underlying coal measures

    NASA Astrophysics Data System (ADS)

    Iverach, Charlotte P.; Beckmann, Sabrina; Cendón, Dioni I.; Manefield, Mike; Kelly, Bryce F. J.

    2017-01-01

    Geochemical and microbiological indicators of methane (CH4) production, oxidation and migration processes in groundwater are important to understand when attributing sources of gas. The processes controlling the natural occurrence of CH4 in groundwater must be understood, especially when considering the potential impacts of the global expansion of coal seam gas (CSG) production on groundwater quality and quantity. We use geochemical and microbiological data, along with measurements of CH4 isotopic composition (δ13C-CH4), to determine the processes acting upon CH4 in a freshwater alluvial aquifer that directly overlies coal measures targeted for CSG production in Australia. Measurements of CH4 indicate that there is biogenic CH4 in the aquifer; however, microbial data indicate that there are no methanogenic archaea in the groundwater. In addition, geochemical data, particularly the isotopes of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC), as well as the concentration of SO42-, indicate limited potential for methanogenesis in situ. Microbial community analysis also shows that aerobic oxidation of CH4 occurs in the alluvial aquifer. The combination of microbiological and geochemical indicators suggests that the most likely source of CH4, where it was present in the freshwater aquifer, is the upward migration of CH4 from the underlying coal measures.

  18. Quality of water in the alluvial aquifer, American Bottoms, East St Louis, Illinois

    USGS Publications Warehouse

    Voelker, David C.

    1984-01-01

    Ground-water levels in the American Bottoms regions around East St. Louis, Illinois, have risen several feet since the early 1970's. Artificial dewatering of the aquifer by increased pumping is being investigated by the U.S. Army Corps of Engineers to alleviate economic and health concerns resulting from elevated ground-water levels. A ground-water quality evaluation is necessary for selecting a feasible dewatering scheme. Analyses of water samples from 63 wells show that except for iron, manganese, and dissolved solids, constituent concentrations do not exceed Illinois water-quality standards. The waters are primarily of the calcium-magnesium-bicarbonate type with some calcium-sulfate type water. Iron concentrations ranged from less than 3 to 82,000 micrograms per liter, manganese from 5 to 5,300 micrograms per liter, and dissolved solids from 140 to 3,000 milligrams per liter. These constituent concentrations exceed Illinois ' public water supply, effluent, and general water-quality standards in most samples and analysis indicates the concentrations are representative of the ambient water quality. Concentrations of nitrite + nitrate nitrogen fluoride, zinc, lead, and sulfate also exceeded Illinois water-quality standards in a few samples. Concentrations of organic pesticides, polychlorinated biphenyls, and polychlorinated naphthalenes were below analytical detection limits. (USGS)

  19. Speciation and Reactivity of Uranium Products Formed during in Situ Bioremediation in a Shallow Alluvial Aquifer

    PubMed Central

    2015-01-01

    In this study, we report the results of in situ U(VI) bioreduction experiments at the Integrated Field Research Challenge site in Rifle, Colorado, USA. Columns filled with sediments were deployed into a groundwater well at the site and, after a period of conditioning with groundwater, were amended with a mixture of groundwater, soluble U(VI), and acetate to stimulate the growth of indigenous microorganisms. Individual reactors were collected as various redox regimes in the column sediments were achieved: (i) during iron reduction, (ii) just after the onset of sulfate reduction, and (iii) later into sulfate reduction. The speciation of U retained in the sediments was studied using X-ray absorption spectroscopy, electron microscopy, and chemical extractions. Circa 90% of the total uranium was reduced to U(IV) in each reactor. Noncrystalline U(IV) comprised about two-thirds of the U(IV) pool, across large changes in microbial community structure, redox regime, total uranium accumulation, and reaction time. A significant body of recent research has demonstrated that noncrystalline U(IV) species are more suceptible to remobilization and reoxidation than crystalline U(IV) phases such as uraninite. Our results highlight the importance of considering noncrystalline U(IV) formation across a wide range of aquifer parameters when designing in situ remediation plans. PMID:25265543

  20. Interaction of a river with an alluvial basin aquifer: Stable isotopes, salinity and water budgets

    NASA Astrophysics Data System (ADS)

    Eastoe, Christopher J.; Hutchison, William R.; Hibbs, Barry J.; Hawley, John; Hogan, James F.

    2010-12-01

    SummaryDetailed sets of tracer data (isotopes, salinity) and the results of MODFLOW modeling of water budgets provide an unprecedented opportunity for comparing modeling with field data in the area where the Rio Grande enters the Hueco Bolson basin of Texas and Chihuahua. Water from the Rio Grande has recharged the Hueco Bolson aquifer to a depth of 300 m below the surface in the El Paso-Ciudad Juárez area, the depth of infiltration corresponding to the depth of ancestral Rio Grande fluvial sediments. Groundwater beneath the river exhibits complex isotope and salinity stratification. Post-dam (post -1916, type A) river water has infiltrated to depths up to 80 m. Pre-dam (type B) river water has infiltrated to 300 m depth near downtown El Paso, and has mixed with, or been displaced further downstream by high-salinity native Hueco Bolson groundwater (type C, present in the basin north of the river). Salinity and isotope boundaries do not correspond precisely. Isotope stratification corresponds to water residence time and (for type C) to degree of evaporation; the highest salinities are associated with the most evaporated water. Modeling of water budgets in the basin fill beneath the river predicts present-day mixing of water types B and C where changing rates of pumping have caused a reversal of groundwater flow direction between El Paso and Ciudad Juárez, and deep recharge of type B water under conditions prevailing in the 1960s.

  1. Infiltration of organic pollutants into groundwater: Field studies in the alluvial aquifer of the Sava River

    SciTech Connect

    Ahel, M. )

    1991-10-01

    Groundwater represents one of the most important sources of potable water for many public water supplies in the world. The benefits of these valuable water reservoirs are being reduced however, due to the increasing infiltration of both inorganic and organic pollutants from different sources such as wastewaters, polluted freshwaters, contaminated soils, sanitary landfills, and industrial dumping sites. Therefore, investigations of pollutant migration and persistence in groundwaters are of great significance for groundwater protection strategies. The study of organic pollutants is perhaps the most complex issue in groundwater pollution chemistry. The extremely high number of possible organic pollutants as well as the severe ecotoxicological effects of specific organic compounds make the assessment of water quality and long term pollution trends in the aquifer very difficult. The application of the computer-assisted high-resolution gas chromatography/mass spectroscopy in the last decade has extended our knowledge about the occurrence of specific organic pollutants in groundwaters and processes that determine their transport and transformation.

  2. Studying the impact of climate change on coastal aquifers and adjacent wetlands

    NASA Astrophysics Data System (ADS)

    Stigter, Tibor; Ribeiro, Luís.; Oliveira, Rodrigo; Samper, Javier; Fakir, Younes; Fonseca, Luís.; Monteiro, José Paulo; Nunes, João. Pedro; Pisani, Bruno

    2010-05-01

    program, assessing the impact of climate change on coastal groundwater resources and dependent ecosystems. These resources are often intensively exploited, potentially leading to saltwater intrusion and the degradation of groundwater and dependent wetlands. Climate change may increase this problem in Mediterranean regions, due to the combined effect of rising sea levels and decreasing aquifer recharge. CLIMWAT aims to address this problem by employing a multimethodological approach involving climate scenarios, surface and groundwater flow and transport modeling, as well as hydrochemical indicator and ecological diversity indices. Research is performed in three coastal areas: the Central Algarve in Portugal, the Ebro delta in Spain and the Atlantic Sahel in Morocco. The mean annual temperatures are 17.4 ° C, 17.2 ° C and 17.5 ° C, respectively, whereas mean annual rainfall is lower in the Atlantic Sahel (390 mm) than in the Ebro Delta (520 mm) and the Central Algarve (660 mm). Work package (WP) 1 involves the collection of existing data (in a GIS environment), baseline characterization and the selection of monitoring locations. These include wells and springs of official (water level/quality) monitoring networks, as well as additional observation points selected at strategic locations, including the wetlands receiving groundwater and adjacent aquifer sectors. In WP2 the climate scenarios are selected and integrated in hydrological models (SWAT, GISBALAN), which are developed and calibrated with existing data, prior to scenario modeling. The main focus of this WP is to estimate the evolution of surface runoff and groundwater recharge under climate change. Data on climate change scenarios and model projections are compiled from: (i) the PRUDENCE project; (ii) the ENSEMBLES project; (iii) IPCC scenarios and projections, AR4; (iv) AEMet (Spanish Meteorological Agency) for generation of regional scenarios of climate change in Spain. For Morocco, where runoff is

  3. Development, calibration, and testing of ground-water flow models for the Mississippi River Valley alluvial aquifer in eastern Arkansas using one-square-mile cells

    USGS Publications Warehouse

    Mahon, G.L.; Poynter, D.T.

    1993-01-01

    Significant water-level declines in the Mississippi River Valley alluvial aquifer prompted the need to better understand the flow system in the aquifer which, in turn, led to the development of digital groundwater flow models of the alluvial aquifer. Two models were developed in the eastern Arkansas study area with the Arkansas River dividing the study area and functioning as a hydrologic boundary to the models. Both models simulate groundwater flow in one layer with recharge entering the aquifer from head-dependent surface infiltration through the overlying confining unit and from seepage through river beds. Digital models were used to simulate flow in the aquifer during seven stress periods between 1918 and 1987. Pumpage used in the simulations ranged from 83,400,000 to 412,000,000 cu ft/d in the north model and from 12,800,000 to 58,500,000 cu ft/d in the south model. Three different spatial and temporal pumpage scenarios were tested to simulate pumpage stress in the models. The pumpage distribution used in the calibrated model was based on a combination of all three scenarios. Several criteria were used during model development to determine how well the model simulated conditions in the aquifer. Potentiometric maps of model-computed water levels were compared to measured data to check the computed water levels and direction of flow. Hydrographs of observation wells were compared to computed water levels at corresponding model cells to assess the temporal distribution of pumpage. A root-mean-square error analysis was performed during calibration by comparing observation-well and model-computed water levels for 1972. Sensitivity analyses were performed to determine the effects of changes in input parameters on computed heads (water levels). Both models were sensitive to changes in recharge and pumpage but the south model generally was less sensitive than the north model.

  4. Effects of Proposed Additional Ground-Water Withdrawals from the Mississippi River Valley Alluvial Aquifer on Water Levels in Lonoke County, Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.

    2006-01-01

    The Grand Prairie Water Users Association, located in Lonoke County, Arkansas, plans to increase ground-water withdrawals from the Mississippi River Valley alluvial aquifer from their current (2005) rate of about 400 gallons per minute to 1,400 gallons per minute (2,016,000 gallons per day). The effect of pumping from a proposed well was simulated using a digital model of ground-water flow. The proposed additional withdrawals were added to an existing pumping cell specified in the model, with increased pumping beginning in 2005, and specified to pump at a total combined rate of 2,016,000 gallons per day for a period of 46 years. In addition, pumping from wells owned by Cabot Water Works, located about 2 miles from the proposed pumping, was added to the model beginning in 2001 and continuing through to the end of 2049. Simulated pumping causes a cone of depression to occur in the alluvial aquifer with a maximum decline in water level of about 8.5 feet in 46 years in the model cell of the proposed well compared to 1998 withdrawals. However, three new dry model cells occur south of the withdrawal well after 46 years. This total water-level decline takes into account the cumulative effect of all wells pumping in the vicinity, although the specified pumping rate from all other model cells in 2005 is less than for actual conditions in 2005. After 46 years with the additional pumping, the water-level altitude in the pumped model cell was about 177.4 feet, which is 41.7 feet higher than 135.7 feet, the altitude corresponding to half of the original saturated thickness of the alluvial aquifer (a metric used to determine if the aquifer should be designated as a Critical Ground-Water Area (Arkansas Natural Resources Commission, 2006)).

  5. Quaternary stratigraphy, sediment characteristics and geochemistry of arsenic-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in central Bangladesh

    NASA Astrophysics Data System (ADS)

    Shamsudduha, M.; Uddin, A.; Saunders, J. A.; Lee, M.-K.

    2008-07-01

    This study focuses on the Quaternary stratigraphy, sediment composition, mineralogy, and geochemistry of arsenic (As)-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in the central Bangladesh. Arsenic concentrations in 85 tubewells in Manikganj area, 70 km northwest of Dhaka City, range from 0.25 µg/L to 191 µg/L with a mean concentration of 33 µg/L. Groundwater is mainly Ca-HCO3 type with high concentrations of dissolved As, Fe, and Mn, but low level of SO4. The uppermost aquifer occurs between 10 m and 80 m below the surface that has a mean arsenic concentration of 35 µg/L. Deeper aquifer (> 100 m depth) has a mean arsenic concentration of 18 µg/L. Sediments in the upper aquifer are mostly gray to dark-gray, whereas sediments in the deep aquifer are mostly yellowing-gray to brown. Quartz, feldspar, mica, hornblende, garnet, kyanite, tourmaline, magnetite, ilmenite are the major minerals in sediments from both aquifers. Biotite and potassium feldspar are dominant in shallow aquifer, although plagioclase feldspar and garnet are abundant in deep aquifer sediments. Sediment composition suggests a mixed provenance with sediment supplies from both orogenic belts and cratons. High arsenic concentrations in sediments are found within the upper 50 m in drilled core samples. Statistical analysis shows that As, Fe, Mn, Ca, and P are strongly correlated in sediments. Concentrations of Cd, Cu, Ni, Zn, and Bi also show strong correlations with arsenic in the Manikganj sediment cores. Authigenic goethite concretions, possibly formed by bacteria, are found in the shallow sediments, which contain arsenic of a concentration as high as 8.8 mg/kg. High arsenic concentrations in aquifers are associated with fine-grained sediments that were derived mostly from the recycled orogens and relatively rapidly deposited mainly by meandering channels during the Early to Middle Holocene rising sea-level conditions.

  6. Quaternary stratigraphy, sediment characteristics and geochemistry of arsenic-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in central Bangladesh.

    PubMed

    Shamsudduha, M; Uddin, A; Saunders, J A; Lee, M-K

    2008-07-29

    This study focuses on the Quaternary stratigraphy, sediment composition, mineralogy, and geochemistry of arsenic (As)-contaminated alluvial aquifers in the Ganges-Brahmaputra floodplain in the central Bangladesh. Arsenic concentrations in 85 tubewells in Manikganj area, 70 km northwest of Dhaka City, range from 0.25 microg/L to 191 microg/L with a mean concentration of 33 microg/L. Groundwater is mainly Ca-HCO(3) type with high concentrations of dissolved As, Fe, and Mn, but low level of SO(4). The uppermost aquifer occurs between 10 m and 80 m below the surface that has a mean arsenic concentration of 35 microg/L. Deeper aquifer (>100 m depth) has a mean arsenic concentration of 18 microg/L. Sediments in the upper aquifer are mostly gray to dark-gray, whereas sediments in the deep aquifer are mostly yellowing-gray to brown. Quartz, feldspar, mica, hornblende, garnet, kyanite, tourmaline, magnetite, ilmenite are the major minerals in sediments from both aquifers. Biotite and potassium feldspar are dominant in shallow aquifer, although plagioclase feldspar and garnet are abundant in deep aquifer sediments. Sediment composition suggests a mixed provenance with sediment supplies from both orogenic belts and cratons. High arsenic concentrations in sediments are found within the upper 50 m in drilled core samples. Statistical analysis shows that As, Fe, Mn, Ca, and P are strongly correlated in sediments. Concentrations of Cd, Cu, Ni, Zn, and Bi also show strong correlations with arsenic in the Manikganj sediment cores. Authigenic goethite concretions, possibly formed by bacteria, are found in the shallow sediments, which contain arsenic of a concentration as high as 8.8 mg/kg. High arsenic concentrations in aquifers are associated with fine-grained sediments that were derived mostly from the recycled orogens and relatively rapidly deposited mainly by meandering channels during the Early to Middle Holocene rising sea-level conditions.

  7. Tracking effluent discharges in undisturbed stony soil and alluvial gravel aquifer using synthetic DNA tracers.

    PubMed

    Pang, Liping; Robson, Beth; Farkas, Kata; McGill, Erin; Varsani, Arvind; Gillot, Lea; Li, Jinhua; Abraham, Phillip

    2017-03-15

    With the intensification of human activities, fresh water resources are increasingly being exposed to contamination from effluent disposal to land. Thus, there is a greater need to identify the sources and pathways of water contamination to enable the development of better mitigation strategies. To track discharges of domestic effluent into soil and groundwater, 10 synthetic double-stranded DNA (dsDNA)(3) tracers were developed in this study. Laboratory column experiment and field groundwater and soil lysimeter studies were carried out spiking DNA with oxidation-pond domestic effluent. The selected DNA tracers were compared with a non-reactive bromide (Br) tracer with respect to their relative mass recoveries, speeds of travel and dispersions using the method of temporal moments. In intact stony soil and gravel aquifer media, the dsDNA tracers typically showed earlier breakthrough and less dispersion than the Br tracer, and underwent mass reduction. This suggests that the dsDNA tracers were predominantly transported through the network of larger pores or preferential flow paths. Effluent tracking experiments in soil and groundwater demonstrated that the dsDNA tracers were readily detectable in effluent-contaminated soil and groundwater using quantitative polymerase chain reaction. DNA tracer spiked in the effluent at quantities of 36μg was detected in groundwater 37m down-gradient at a concentration 3-orders of magnitude above the detection limit. It is anticipated it could be detected at far greater distances. Our findings suggest that synthetic dsDNA tracers are promising for tracking effluent discharges in soils and groundwater but further studies are needed to investigate DNA-effluent interaction and the impact of subsurface environmental conditions on DNA attenuation. With further validation, synthetic dsDNA tracers, especially when multiple DNA tracers are used concurrently, can be an effective new tool to track effluent discharge in soils and groundwater

  8. River infiltration to a subtropical alluvial aquifer inferred using multiple environmental tracers

    NASA Astrophysics Data System (ADS)

    Lamontagne, S.; Taylor, A. R.; Batlle-Aguilar, J.; Suckow, A.; Cook, P. G.; Smith, S. D.; Morgenstern, U.; Stewart, M. K.

    2015-06-01

    Chloride (Cl-), stable isotope ratios of water (δ18O and δ2H), sulfur hexafluoride (SF6), tritium (3H), carbon-14 (14C), noble gases (4He, Ne, and Ar), and hydrometry were used to characterize groundwater-surface water interactions, in particular infiltration rates, for the Lower Namoi River (New South Wales, Australia). The study period (four sampling campaigns between November 2009 and November 2011) represented the end of a decade-long drought followed by several high-flow events. The hydrometry showed that the river was generally losing to the alluvium, except when storm-derived floodwaves in the river channel generated bank recharge—discharge cycles. Using 3H/14C-derived estimates of groundwater mean residence time along the transect, infiltration rates ranged from 0.6 to 5 m yr-1. However, when using the peak transition age (a more realistic estimate of travel time in highly dispersive environments), the range in infiltration rate was larger (4-270 m yr-1). Both river water (highest δ2H, δ18O, SF6, 3H, and 14C) and an older groundwater source (lowest δ2H, δ18O, SF6, 3H, 14C, and highest 4He) were found in the riparian zone. This old groundwater end-member may represent leakage from an underlying confined aquifer (Great Artesian Basin). Environmental tracers may be used to estimate infiltration rates in this riparian environment but the presence of multiple sources of water and a high dispersion induced by frequent variations in the water table complicates their interpretation.

  9. Hydrogeology of the surficial and intermediate aquifer systems in Sarasota and adjacent counties, Florida

    USGS Publications Warehouse

    Barr, G.L.

    1996-01-01

    From 1991 to 1995, the hydrogeology of the surficial aquifer system and the major permeable zones and confining units of the intermediate aquifer system in southwest Florida was studied. The study area is a 1,400-square-mile area that includes Sarasota County and parts of Manatee, De Soto, Charlotte, and Lee Counties. Lithologic, geophysical, hydraulic property, and water-level data were used to correlate the hydrogeology and map the extent of the aquifer systems. Water chemistry was evaluated in southwest Sarasota County to determine salinity of the surficial and intermediate aquifer systems. The surficial aquifer is an unconfined aquifer system that overlies the intermediate aquifer system and ranges from a few feet to over 60 feet in thickness in the study area. Hydraulic properties of the surficial aquifer system determined from aquifer and laboratory tests, and model simulations vary considerably across the study area. The intermediate aquifer system, a confined aquifer system that lies between the surficial and the Upper Floridan aquifers, is composed of alternating confining units and permeable zones. The intermediate aquifer system has three major permeable zones that exhibit a wide range of hydraulic properties. Horizontal flow in the intermediate aquifer system is northeast to southwest. Most of the study area is in a discharge area of the intermediate aquifer system. Water ranges naturally from fresh in the surficial aquifer system and upper permeable zones of the intermediate aquifer system to moderately saline in the lower permeable zone. Water-quality data collected in coastal southwest Sarasota County indicate that ground-water withdrawals from major pumping centers have resulted in lateral seawater intrusion and upconing into the surficial and intermediate aquifer systems.

  10. Simulated Ground-Water Withdrawals by Cabot WaterWorks from the Mississippi River Valley Alluvial Aquifer, Lonoke County, Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.

    2007-01-01

    Cabot WaterWorks, located in Lonoke County, Arkansas, plans to increase ground-water withdrawals from the Mississippi River Valley alluvial aquifer from a 2004 rate of approximately 2.24 million gallons per day to between 4.8 and 8 million gallons per day by the end of 2049. The effects of increased pumping from several wells were simulated using a digital model of ground-water flow. The proposed additional withdrawals by Cabot WaterWorks were specified in three 1-square-mile model cells with increased pumping beginning in 2007. Increased pumping was specified at various combined rates for a period of 44 years. In addition, augmented pumping from wells owned by Grand Prairie Water Users Association, located about 2 miles from the nearest Cabot WaterWorks wells, was added to the model beginning in 2007 and continuing through to the end of 2049 in 10 of the 16 scenarios analyzed. Eight of the scenarios included reductions in pumping rates in model cells corresponding to either the Grand Prairie Water Users Association wells or to wells contained within the Grand Prairie Area Demonstration Project. Drawdown at the end of 44 years of pumping at 4.8 million gallons per day from the Cabot WaterWorks wells ranged from 15 to 25 feet in the three model cells; pumping at 8 million gallons per day resulted in water-level drawdown ranging from about 15 to 40 feet. Water levels in those cells showed no indication of leveling out at the end of the simulation period, indicating non-steady-state conditions after 44 years of pumping. From one to four new dry cells occurred in each of the scenarios by the end of 2049 when compared to a baseline scenario in which pumping was maintained at 2004 rates, even in scenarios with reduced pumping in the Grand Prairie Area Demonstration Project; however, reduced pumping produced cells that were no longer dry when compared to the baseline scenario at the end of 2049. Saturated thickness at the end of 2049 in the three Cabot WaterWorks wells

  11. A new method of combined techniques for characterization and monitoring of seawater interface in an alluvial aquifer

    NASA Astrophysics Data System (ADS)

    Folch, Albert; del Val, Laura; Luquot, Linda; Martínez, Laura; Bellmunt, Fabian; Le Lay, Hugo; Rodellas, Valentí; Ferrer, Núria; Fernández, Sheila; Ledo, Juanjo; Pezard, Philippe; Bour, Olivier; Queralt, Pilar; Marcuello, Alex; García-Orellana, Jordi; Saaltink, Maarten; Vázquez-Suñé, Enric; Carrera, Jesús

    2016-04-01

    Understand the dynamics of the fresh-salt water interface in aquifers is a key issue to comprehend mixing process and to quantity the discharge of nutrients in to coastal areas. In order to go beyond the current knowledge in this issue an experimental site has been set up at the alluvial aquifer Riera Argentona (Barcelona - Spain). The site comprises 16 shallow piezometers installed between 30 and 90 m from the seashore, with depths ranging between 15 and 25 meters. The seawater interface is being monitored using several techniques, the combination of which will help us to understand the spatial and temporal behaviour of the mixing zone and the geochemical processes occurring there. Specially the deepest piezometers are equipped with electrodes in order to perform cross-hole electrical resistivity tomography (CHERT). In addition, all piezometers are also equipped with Fiber Optic cable to perform distributed temperature measurements. Two single steel armoured fibre optic cable lines of around 600m length were installed in all boreholes. The objective is to use the cable both as passive and active temperature sensor. The first is being done for the continuous monitoring of temperature whereas; the second provides a higher temperature resolution used to monitor field experiments. Periodic CHERT measurements are carried out between the piezometer equipped with electrodes, resulting in parallel and perpendicular vertical cross sections of the site resistivity. The position of the fresh-salt water interface can be identified due to the resistivity contrast between the saline and fresh water. Preliminary results of periodic distributed temperature measurements will be also be used to monitor the position of the mixing zone thanks to the contrast and seasonal temperature changes. Periodic down-hole EC profiles will be used to validate the method. Acknowledgements This work was funded by the projects CGL2013-48869-C2-1 y CGL2013-48869-C2-2-R of the Spanish Government. We

  12. Size-fractionation of groundwater arsenic in alluvial aquifers of West Bengal, India: the role of organic and inorganic colloids.

    PubMed

    Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Chatterjee, Debashis; Roman-Ross, Gabriela; Hidalgo, Manuela

    2014-01-15

    Dissolved organic carbon (DOC) and Fe mineral phases are known to influence the mobility of arsenic (As) in groundwater. Arsenic can be associated with colloidal particles containing organic matter and Fe. Currently, no data is available on the dissolved phase/colloidal association of As in groundwater of alluvial aquifers in West Bengal, India. This study investigated the fractional distribution of As (and other metals/metalloids) among the particulate, colloidal and dissolved phases in groundwater to decipher controlling behavior of organic and inorganic colloids on As mobility. The result shows that 83-94% of As remained in the 'truly dissolved' phases (i.e., <0.05 μm size). Strong positive correlation between Fe and As (r(2) between 0.65 and 0.94) is mainly observed in the larger (i.e., >0.05 μm size) colloidal particles, which indicates the close association of As with larger Fe-rich inorganic colloids. In smaller (i.e., <0.05 μm size) colloidal particles strong positive correlation is observed between As and DOC (r(2)=0.85), which highlights the close association of As with smaller organic colloids. As(III) is mainly associated with larger inorganic colloids, whereas, As(V) is associated with smaller organic/organometallic colloids. Scanning Electron Microscopy and Energy Dispersive X-ray spectroscopy confirm the association of As with DOC and Fe mineral phases suggesting the formation of dissolved organo-Fe complexes and colloidal organo-Fe oxide phases. Attenuated total reflectance-Fourier transform infrared spectroscopy further confirms the formation of As-Fe-NOM organometallic colloids, however, a detailed study of these types of colloids in natural waters is necessary to underpin their controlling behavior.

  13. Quality of shallow ground water in alluvial aquifers of the Willamette Basin, Oregon, 1993-95

    USGS Publications Warehouse

    Hinkle, Stephen R.

    1997-01-01

    The current (1993?95) quality of shallow ground water (generally, <25 meters below land surface) in Willamette Basin alluvium is described using results from two studies. A Study-Unit Survey, or regional assessment of shallow groundwater quality in alluvium, was done from June through August 1993. During the Study-Unit Survey, data were collected from 70 domestic wells chosen using a random-selection process and located mostly in areas of agricultural land use. An urban Land-Use Study, which was a reconnaissance of shallow urban ground-water quality from 10 monitoring wells installed in areas of residential land use, was done in July 1995. Concentrations of nitrite plus nitrate (henceforth, nitrate, because nitrite concentrations were low) ranged from <0.05 to 26 mg N/L (milligrams nitrogen per liter) in ground water from 70 Study-Unit-Survey wells; concentrations exceeded the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg N/L in 9 percent of Study-Unit-Survey samples. Relationships were observed between nitrate concentrations and dissolved-oxygen concentrations, the amount of clay present within and overlying aquifers, overlying geology, and upgradient land use. Tritium (3H) data indicate that 21 percent of Study-Unit-Survey samples represented water recharged prior to 1953. Nitrogen-fertilizer application rates in the basin have increased greatly over the past several decades. Thus, some observed nitrate concentrations may reflect nitrogen loading rates that were smaller than those presently applied in the basin. Concentrations of phosphorus ranged from <0.01 to 2.2 mg/L in 70 Study-Unit-Survey wells and exceeded 0.10 mg/L in 60 percent of the samples. Phosphorus and nitrate concentrations were inversely correlated. From 1 to 5 pesticides and pesticide degradation products (henceforth, pesticides) were detected in ground water from each of 23 Study-Unit-Survey wells (33 percent of 69 wells sampled for pesticides) for a total

  14. Filtration and transport of Bacillus subtilis spores and the F-RNA phage MS2 in a coarse alluvial gravel aquifer: Implications in the estimation of setback distances

    NASA Astrophysics Data System (ADS)

    Pang, Liping; Close, Murray; Goltz, Mark; Noonan, Mike; Sinton, Lester

    2005-04-01

    Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates ( katt) that were determined by applying the model to the breakthrough data, filter factors ( f) were calculated and compared with f values estimated from the slopes of log ( cmax/ co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log ( cmax/ co) m -1, are consistently in the order of 10 -2 for clean coarse gravel aquifers, 10 -3 for contaminated coarse gravel aquifers, and generally 10 -1 for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10 4 pfu/l for enteroviruses and 10 6 cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking

  15. Filtration and transport of Bacillus subtilis spores and the F-RNA phage MS2 in a coarse alluvial gravel aquifer: implications in the estimation of setback distances.

    PubMed

    Pang, Liping; Close, Murray; Goltz, Mark; Noonan, Mike; Sinton, Lester

    2005-04-01

    Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates (katt) that were determined by applying the model to the breakthrough data, filter factors (f) were calculated and compared with f values estimated from the slopes of log (cmax/co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log (cmax/co) m(-1), are consistently in the order of 10(-2) for clean coarse gravel aquifers, 10(-3) for contaminated coarse gravel aquifers, and generally 10(-1) for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10(4) pfu/l for enteroviruses and 10(6) cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking

  16. Hydrogeology and simulation of groundwater flow and analysis of projected water use for the Canadian River alluvial aquifer, western and central Oklahoma

    USGS Publications Warehouse

    Ellis, John H.; Mashburn, Shana L.; Graves, Grant M.; Peterson, Steven M.; Smith, S. Jerrod; Fuhrig, Leland T.; Wagner, Derrick L.; Sanford, Jon E.

    2017-02-13

    This report describes a study of the hydrogeology and simulation of groundwater flow for the Canadian River alluvial aquifer in western and central Oklahoma conducted by the U.S. Geological Survey in cooperation with the Oklahoma Water Resources Board. The report (1) quantifies the groundwater resources of the Canadian River alluvial aquifer by developing a conceptual model, (2) summarizes the general water quality of the Canadian River alluvial aquifer groundwater by using data collected during August and September 2013, (3) evaluates the effects of estimated equal proportionate share (EPS) on aquifer storage and streamflow for time periods of 20, 40, and 50 years into the future by using numerical groundwater-flow models, and (4) evaluates the effects of present-day groundwater pumping over a 50-year period and sustained hypothetical drought conditions over a 10-year period on stream base flow and groundwater in storage by using numerical flow models. The Canadian River alluvial aquifer is a Quaternary-age alluvial and terrace unit consisting of beds of clay, silt, sand, and fine gravel sediments unconformably overlying Tertiary-, Permian-, and Pennsylvanian-age sedimentary rocks. For groundwater-flow modeling purposes, the Canadian River was divided into Reach I, extending from the Texas border to the Canadian River at the Bridgeport, Okla., streamgage (07228500), and Reach II, extending downstream from the Canadian River at the Bridgeport, Okla., streamgage (07228500), to the confluence of the river with Eufaula Lake. The Canadian River alluvial aquifer spans multiple climate divisions, ranging from semiarid in the west to humid subtropical in the east. The average annual precipitation in the study area from 1896 to 2014 was 34.4 inches per year (in/yr).A hydrogeologic framework of the Canadian River alluvial aquifer was developed that includes the areal and vertical extent of the aquifer and the distribution, texture variability, and hydraulic properties of

  17. Water levels and selected water-quality conditions in the Mississippi River Valley alluvial aquifer in Eastern Arkansas, 2008

    USGS Publications Warehouse

    Schrader, T.P.

    2010-01-01

    During the spring of 2008, the U.S. Geological Survey, in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey, measured 670 water levels in 659 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. Groundwater levels are affected by groundwater withdrawals resulting in potentiometric-surface depressions. In 2008, the lowest water-level altitude was 69 feet above National Geodetic Vertical Datum of 1929 in the center of Arkansas County. The highest water-level altitude was 288 feet above National Geodetic Vertical Datum of 1929 in northeastern Clay County on the west side of Crowleys Ridge. Two large depressions in the potentiometric surface are located in Arkansas, Lonoke, and Prairie Counties and west of Crowleys Ridge in Craighead, Cross, Lee, Monroe, Poinsett, St. Francis, and Woodruff Counties. The elongated depression in Arkansas, Lonoke, and Prairie Counties has two areas that have changed in horizontal area or depth when compared to previous conditions of the aquifer. The area in Arkansas County in the southeastern half of the depression has not expanded horizontally from recent years, although the center of the depression has deepened. The area in Lonoke and Prairie Counties in the northwestern half of the depression has not expanded and water level in the deeper part of the depression has risen. In Lonoke and Prairie Counties in the northwestern half of the depression, the 90-foot contour shown on the 2006 potentiometric-surface map is not shown on the 2008 potentiometric-surface map. Along the west side of Crowleys Ridge, the area enclosed by 140-foot contour in Cross and Poinsett Counties has expanded further south into Cross County. The 130-foot contour in Poinsett County expanded north in 2008. The 130-foot contour is shown in Cross County, which was not evident in previous years. The 130-foot contour in St. Francis, Monroe, and Woodruff Counties in 2006 is not shown on the 2008

  18. Simulation of ground-water flow, contributing recharge areas, and ground-water travel time in the Missouri River alluvial aquifer near Ft. Leavenworth, Kansas

    USGS Publications Warehouse

    Kelly, Brian P.

    2004-01-01

    The Missouri River alluvial aquifer near Ft. Leavenworth, Kansas, supplies all or part of the drinking water for Ft. Leavenworth; Leavenworth, Kansas; Weston, Missouri; and cooling water for the Kansas City Power and Light, Iatan Power Plant. Ground water at three sites within the alluvial aquifer near the Ft. Leavenworth well field is contaminated with trace metals and organic compounds and concerns have been raised about the potential contamination of drinking-water supplies. In 2001, the U.S. Geological Survey, U.S. Army Corps of Engineers, and the U.S. Army began a study of ground-water flow in the Missouri River alluvial aquifer near Ft. Leavenworth. Hydrogeologic data from 173 locations in the study area was used to construct a ground-water flow model (MODFLOW-2000) and particle-tracking program (MODPATH) to determine the direction and travel time of ground-water flow and contributing recharge areas for water-supply well fields within the alluvial aquifer. The modeled area is 28.6 kilometers by 32.6 kilometers and contains the entire study area. The model uses a uniform grid size of 100 meters by 100 meters and contains 372,944 cells in 4 layers, 286 columns, and 326 rows. The model represents the alluvial aquifer using four layers of variable thickness with no intervening confining layers. The model was calibrated to both quasi-steady-state and transient hydraulic head data collected during the study and ground-water flow was simulated for five well-pumping/river-stage scenarios. The model accuracy was calculated using the root mean square error between actual measurements of hydraulic head and model generated hydraulic head at the end of each model run. The accepted error for the model calibrations were below the maximum measurement errors. The error for the quasi-steady-state calibration was 0.82 meter; for the transient calibration it was 0.33 meter. The shape, size, and ground-water travel time within the contributing recharge area for each well or well

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

    PubMed

    Apaydın, Ahmet; Aktaş, Sibel Demirci

    2012-04-01

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

  20. Inverse geochemical modeling of groundwater evolution with emphasis on arsenic in the Mississippi River Valley alluvial aquifer, Arkansas (USA)

    USGS Publications Warehouse

    Sharif, M.U.; Davis, R.K.; Steele, K.F.; Kim, B.; Kresse, T.M.; Fazio, J.A.

    2008-01-01

    Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater with emphasis on arsenic (As) release under reducing conditions in the shallow (25-30 m) Mississippi River Valley Alluvial aquifer, Arkansas, USA. The modeling was based on flow paths defined by high-precision (??2 cm) water level contour map; X-ray diffraction (XRD), scanning electron microscopic (SEM), and chemical analysis of boring-sediments for minerals; and detailed chemical analysis of groundwater along the flow paths. Potential phases were constrained using general trends in chemical analyses data of groundwater and sediments, and saturation indices data (MINTEQA2) of minerals in groundwater. Modeling results show that calcite, halite, fluorite, Fe oxyhydroxide, organic matter, H2S (gas) were dissolving with mole transfers of 1.40E - 03, 2.13E - 04, 4.15E - 06, 1.25E + 01, 3.11, and 9.34, respectively along the dominant flow line. Along the same flow line, FeS, siderite, and vivianite were precipitating with mole transfers of 9.34, 3.11, and 2.64E - 07, respectively. Cation exchange reactions of Ca2+ (4.93E - 04 mol) for Na+ (2.51E - 04 mol) on exchange sites occurred along the dominant flow line. Gypsum dissolution reactions were dominant over calcite dissolution in some of the flow lines due to the common ion effect. The concentration of As in groundwater ranged from <0.5 to 77 ??g/L. Twenty percent total As was complexed with Fe and Mn oxyhydroxides. The redox environment, chemical data of sediments and groundwater, and the results of inverse geochemical modeling indicate that reductive dissolution of Fe oxyhydroxide is the dominant process of As release in the groundwater. The relative rate of reduction of Fe oxyhydroxide over SO42 - with co-precipitation of As into sulfide is the limiting factor controlling dissolved As in groundwater. ?? 2007 Elsevier B.V. All rights reserved.

  1. Status of water levels and selected water-quality conditions in the Mississippi River Valley alluvial aquifer in eastern Arkansas, 1994-96

    USGS Publications Warehouse

    Stanton, Gregory P.; Joseph, Robert L.; Pugh, Aaron L.

    1998-01-01

    During the spring of 1994 and 1996, water levels were measured in more than 600 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. Water samples were collected during the summer of 1995 from about 375 wells completed in the alluvial aquifer and measured for specific conductance. Concentrations of dissolved chloride were analyzed in 314 of the samples, and concentrations of dissolved calcium, magnesium, and sodium were analyzed in 18 of the samples. The regional direction of ground-water flow is generally to the south and east except where affected by ground-water withdrawals. A large depression in the potentiometric surface is located in Arkansas, Lonoke, and Prairie Counties. The comparison of water-level altitudes from 1994 to 1996 reveals that water levels declined and the cone of depression became larger. The water-level altitudes did not decline in every well monitored from 1994 to 1996; however, most water-level altitudes declined during this period and cones of depression became deeper. Shallower depressions are located in Poinsett, Lee, St. Francis, and Woodruff Counties. Potentiometric depressions in this aquifer generally are a result of long-term pumping and probably are affected by variations in aquifer characteristics such as thickness and hydraulic conductivity. Long-term water levels typically declined an average rate of about 1.2 feet per year in the areas of potentiometric depression. Specific conductance ranged from 81 microsiemens per centimeter at 25 degrees Celsius in Drew County to 4,640 microsiemens per centimeter at 25 degrees Celsius in Chicot County. The lowest ground-water specific-conductance values generally occur along the western border of the study area. Several areas exhibited increased specific conductance with the most prominent areas centered in Chicot, Desha, and northern Arkansas County.

  2. Assessing the effectiveness of land and water management practices on nonpoint source nitrate levels in an alluvial stream-aquifer system.

    PubMed

    Bailey, Ryan T; Gates, Timothy K; Romero, Erica C

    2015-08-01

    The search for ways to allay subsurface nitrate pollution and loading to streams over broad regional landscapes is taken up using a calibrated groundwater model supported by extensive field data. Major processes of transport and chemical reaction are considered in the irrigated vadose zone and the underlying alluvial aquifer in interaction with Colorado's Lower Arkansas River and its tributaries. Simulation of a variety of best management practices reveals that there is potential to lower regional nitrate concentrations in groundwater by up to about 40% and mass loading to the river network by up to 70% over a four-decade span. Over the 27BMP scenarios considered in this study, the most effective singular measures are reduction of fertilizer application and sealing of irrigation canals, while combinations of reduced fertilizer application, reduced irrigation application, canal sealing, and enhanced riparian buffer zones are predicted to have the greatest overall impact. Intermittent fallowing of 25% of the land to lease irrigation water also is found to be promising, resulting in a forecasted decrease of about 15% in nitrate groundwater loading to streams. Due to the strong similarity between the study region and other irrigated, fertilized alluvial river valley stream-aquifer systems worldwide, results of this study are expected to be broadly applicable.

  3. Using hydrochemical data and modelling to enhance the knowledge of groundwater flow and quality in an alluvial aquifer of Zagreb, Croatia.

    PubMed

    Marković, Tamara; Brkić, Željka; Larva, Ozren

    2013-08-01

    The Zagreb alluvial aquifer system is located in the southwest of the Pannonian Basin in the Sava Valley in Croatia. It is composed of Quaternary unconsolidated deposits and is highly utilised, primarily as a water supply for the more than one million inhabitants of the capital city of Croatia. To determine the origin and dynamics of the groundwater and to enhance the knowledge of groundwater flow and the interactions between the groundwater and surface water, extensive hydrogeological and hydrochemical investigations have been completed. The groundwater levels monitored in nested observation wells and the lithological profile indicate that the aquifer is a single hydrogeologic unit, but the geochemical characteristics of the aquifer indicate stratification. The weathering of carbonate and silicate minerals has an important role in groundwater chemistry, especially in the area where old meanders of the Sava River existed. Groundwater quality was observed to be better in the deeper parts of the aquifer than in the shallower parts. Furthermore, deterioration of the groundwater quality was observed in the area under the influence of the landfill. The stable isotopic composition of all sampled waters indicates meteoric origin. NETPATH-WIN was used to calculate the mixing proportions between initial waters (water from the Sava River and groundwater from "regional" flow) in the final water (groundwater sampled from observation wells). According to the results, the mixing proportions of "regional" flow and the river water depend on hydrological conditions, the duration of certain hydrological conditions and the vicinity of the Sava River. Moreover, although the aquifer system behaves as a single hydrogeologic unit from a hydraulic point of view, it still clearly demonstrates geochemical stratification, which could be a decisive factor in future utilisation strategies for the aquifer system.

  4. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Oklahoma City to Eufaula Lake in east-central Oklahoma

    USGS Publications Warehouse

    Adams, G.P.; Runkle, Donna; Rea, Alan; Becker, C.J.

    1997-01-01

    ARC/INFO export and nonproprietary format files This diskette contains digitized aquifer boundaries and maps of of hydraulic conductivity, recharge, and ground-water level elevation contours for the alluvial and terrace deposits along the North Canadian River from Oklahoma City to Eufaula Lake in east-central Oklahoma. Ground water in 710 square miles of Quaternary-age alluvial and terrace deposits along the North Canadian River is an important source of water for irrigation, industrial, municipal, stock, and domestic supplies. The aquifer, composed of alluvial and terrace deposits, consists of sand, silt, clay, and gravel. The aquifer is underlain and in hydraulic connection with the upper zone of the Permian-age Garber-Wellington aquifer and the Pennsylvanian-age Ada-Vamoosa aquifer. Most of the lines in the four digital data sets were digitized from a published ground-water modeling report but portions of the aquifer boundary data set was extracted from published digital geologic data sets. 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.

  5. Hydrogeology and water quality in the Snake River alluvial aquifer at Jackson Hole Airport, Jackson, Wyoming, water years 2011 and 2012

    USGS Publications Warehouse

    Wright, Peter R.

    2013-01-01

    The hydrogeology and water quality of the Snake River alluvial aquifer at the Jackson Hole Airport in northwest Wyoming was studied by the U.S. Geological Survey, in cooperation with the Jackson Hole Airport Board, during water years 2011 and 2012 as part of a followup to a previous baseline study during September 2008 through June 2009. Hydrogeologic conditions were characterized using data collected from 19 Jackson Hole Airport wells. Groundwater levels are summarized in this report and the direction of groundwater flow, hydraulic gradients, and estimated groundwater velocity rates in the Snake River alluvial aquifer underlying the study area are presented. Analytical results of groundwater samples collected from 10 wells during water years 2011 and 2012 are presented and summarized. The water table at Jackson Hole Airport was lowest in early spring and reached its peak in July or August, with an increase of 12.5 to 15.5 feet between April and July 2011. Groundwater flow was predominantly horizontal but generally had the hydraulic potential for downward flow. Groundwater flow within the Snake River alluvial aquifer at the airport was from the northeast to the west-southwest, with horizontal velocities estimated to be about 25 to 68 feet per day. This range of velocities slightly is broader than the range determined in the previous study and likely is due to variability in the local climate. The travel time from the farthest upgradient well to the farthest downgradient well was approximately 52 to 142 days. This estimate only describes the average movement of groundwater, and some solutes may move at a different rate than groundwater through the aquifer. The quality of the water in the alluvial aquifer generally was considered good. Water from the alluvial aquifer was fresh, hard to very hard, and dominated by calcium carbonate. No constituents were detected at concentrations exceeding U.S. Environmental Protection Agency maximum contaminant levels or health

  6. Configuration of the top of the Floridan aquifer, Southwest Florida Water Management District and adjacent areas

    USGS Publications Warehouse

    Buono, A.; Rutledge, A.T.

    1978-01-01

    This map depicts the approximate top of the rock that composes the Floridan aquifer. The contours represent the elevation of the top of the Floridan aquifer to mean sea level. Rock units recognized to be part of the Floridan aquifer are limestone and dolomite ranging from middle Eocene to early Miocene. They are Lake City Limestone, Avon Park Limestone, Ocala Limestone, Suwannee Limestone, and Tampa Limestone. In this report, the top of the Floridan aquifer is a limestone defined as the first consistent rock of early Miocene age or older below which occur no clay confining beds. Although the Hawthorn formation of middle Miocene is considered part of the Floridan aquifer when it is in direct hydrologic contact with lower lying rock units, it is not considered here because of a lack of detailed delineation of areas where contact exists. (Woodard-USGS)

  7. An Induced Infiltration and Groundwater Transfer Project to Enhance Recharge in the Lower Mississippi River Valley Alluvial Aquifer: Modeling and Analysis

    NASA Astrophysics Data System (ADS)

    Rigby, J.; Haugh, C. J.; Barlow, J.

    2015-12-01

    The Lower Mississippi River Basin is one of the major agricultural production regions in the United States producing over two-thirds of the rice, nearly half of sugarcane produced in the U.S., as well as significant amounts of soybeans, corn, and cotton. While the region experiences over 50 inches of precipitation annually, reaching yield potential for crops requires irrigation. Approximately 75% of crop acres in the alluvial valley are irrigated, and the expectation is that all acreage will eventually be irrigated. Currently over 90% of water for crop irrigation is derived from the shallow alluvial aquifer outpacing net recharge by several million acre-feet per year. This has resulted in severe groundwater declines in Arkansas and an increasingly threatening situation in northwestern Mississippi. In Mississippi, direct injection has received increasing attention as a means of artificial recharge, though water quality remains a concern both for the integrity of the aquifer and efficiency of injection. This project considers the use of pumping wells near major rivers known to be in connection with the aquifer to induce additional infiltration of surface water by steepening local gradients. The pumped water would be transferred by pipeline to areas within the regional cone of depression where it is then injected to enhance groundwater recharge. Groundwater flow modeling with zone budget analysis is used to evaluate the potential for net supply gains from induced infiltration at potential sites along major rivers in the region. The groundwater model will further evaluate the impact of the transfer and direct injection on regional water tables.

  8. Evaluating the Performance of Short-Term Heat Storage in Alluvial Aquifer with 4D Electrical Resistivity Tomography and Hydrological Monitoring

    NASA Astrophysics Data System (ADS)

    Hermans, T.; Robert, T.; Paulus, C.; Bolly, P. Y.; Koo Seen Lin, E.; Nguyen, F.

    2015-12-01

    In the context of energy demand side management (DSM), energy storage solutions are needed to store energy during high production periods and recover energy during high demand periods. Among currently studied solutions, storing energy in the subsurface through heat pumps and/or exchangers (thermal energy storage) is relatively simple with low investment costs. However, the design and functioning of such systems have strong interconnections with the geology of the site which may be complex and heterogeneous, making predictions difficult. In this context, local temperature measurements are necessary but not sufficient to model heat flow and transport in the subsurface. Electrical resistivity tomography (ERT) provides spatially distributed information on the temperature distribution in the subsurface. In this study, we monitored, with 4D ERT combined with multiple hydrological measurements in available wells, a short-term heat storage experiment in a confined alluvial aquifer. We injected heated water (ΔT=30K) during 6 hours with a rate of 3 m³/h. We stored this heat during 3 days, and then we pumped it back to estimate the energy balance. We collected ERT data sets using 9 parallel profiles of 21 electrodes and cross-lines measurements. Inversion results clearly show the ability of ERT to delimit the thermal plume growth during injection, the diffusion and decrease of temperature during storage, and the decrease in size after pumping. Quantitative interpretation of ERT in terms of temperature estimates is difficult at this stage due to strong spatial variations of the total dissolved solid content in the aquifer, due to historical chloride contamination of the site. However, we demonstrated that short-term heat storage in alluvial aquifer is efficient and that ERT combined with hydrological measurements is a valuable tool to image and estimate the temperature distribution in the subsurface. Moreover, energy balance shows that up to 75% of the energy can be easily

  9. Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004

    USGS Publications Warehouse

    Welch, Heather L.; Kingsbury, James A.; Tollett, Roland W.; Seanor, Ronald C.

    2009-01-01

    The Mississippi embayment-Texas coastal uplands aquifer system is an important source of drinking water, providing about 724 million gallons per day to about 8.9 million people in Texas, Louisiana, Mississippi, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Alabama. The Mississippi River Valley alluvial aquifer ranks third in the Nation for total withdrawals of which more than 98 percent is used for irrigation. From 1994 through 2004, water-quality samples were collected from 169 domestic, monitoring, irrigation, and public-supply wells in the Mississippi embayment-Texas coastal uplands aquifer system and the Mississippi River Valley alluvial aquifer in various land-use settings and of varying well capacities as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Groundwater samples were analyzed for physical properties and about 200 water-quality constituents, including total dissolved solids, major inorganic ions, trace elements, radon, nutrients, dissolved organic carbon, pesticides, pesticide degradates, and volatile organic compounds. The occurrence of nutrients and pesticides differed among four groups of the 114 shallow wells (less than or equal to 200 feet deep) in the study area. Tritium concentrations in samples from the Holocene alluvium, Pleistocene valley trains, and shallow Tertiary wells indicated a smaller component of recent groundwater than samples from the Pleistocene terrace deposits. Although the amount of agricultural land overlying the Mississippi River Valley alluvial aquifer was considerably greater than areas overlying parts of the shallow Tertiary and Pleistocene terrace deposits wells, nitrate was rarely detected and the number of pesticides detected was lower than other shallow wells. Nearly all samples from the Holocene alluvium and Pleistocene valley trains were anoxic, and the reducing conditions in these aquifers likely result in denitrification of nitrate. In contrast, most samples from the

  10. Predictive models applied to groundwater level forecasting: a preliminary experience on the alluvial aquifer of the Magra River (Italy).

    NASA Astrophysics Data System (ADS)

    Brozzo, Gianpiero; Doveri, Marco; Lelli, Matteo; Scozzari, Andrea

    2010-05-01

    Computer-based decision support systems are getting a growing interest for water managing authorities and water distribution companies. This work discusses a preliminary experience in the application of computational intelligence in a hydrological modeling framework, regarding the study area of the alluvial aquifer of the Magra River (Italy). Two sites in the studied area, corresponding to two distinct groups of wells (Battifollo and Fornola) are managed by the local drinkable water distribution company (ACAM Acque), which serves the area of La Spezia, on the Ligurian coast. Battifollo has 9 wells with a total extraction rate of about 240 liters per second, while Fornola has 44 wells with an extraction rate of about 900 liters per second. Objective of this work is to make use of time series coming from long-term monitoring activities in order to assess the trend of the groundwater level with respect to a set of environmental and exploitation parameters; this is accomplished by the experimentation of a suitable model, eligible to be used as a predictor. This activity moves on from the modeling of the system behavior, based on a set of Input/Output data, in order to characterize it without necessarily a prior knowledge of any deterministic mechanism (system identification). In this context, data series collected by continuous hydrological monitoring instrumentation installed in the studied sites, together with meteorological and water extraction data, have been analyzed in order to assess the applicability and performance of a predictive model of the groundwater level. A mixed approach (both data driven and process-based) has been experimented on the whole dataset relating to the last ten years of continuous monitoring activity. The system identification approach presented here is based on the integration of an adaptive technique based on Artificial Neural Networks (ANNs) and a blind deterministic identification approach. According to this concept, the behavior of

  11. Geochemical evidence of groundwater flow paths and the fate and transport of constituents of concern in the alluvial aquifer at Fort Wingate Depot Activity, New Mexico, 2009

    USGS Publications Warehouse

    Robertson, Andrew J.; Henry, David W.; Langman, Jeffery B.

    2013-01-01

    As part of an environmental investigation at Fort Wingate Depot Activity, New Mexico, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, interpreted aqueous geochemical concentrations to better understand the groundwater flow paths and the fate and transport of constituents of concern in the alluvial aquifer underlying the study area. The fine-grained nature of the alluvial matrix creates a highly heterogeneous environment, which adds to the difficulty of characterizing the flow of groundwater and the fate of aqueous constituents of concern. The analysis of the groundwater geochemical data collected in October 2009 provides evidence that is used to identify four groundwater flow paths and their extent in the aquifer and indicates the dominant attenuation processes for the constituents of concern. The extent and interaction of groundwater flow paths were delineated by the major ion concentrations and their relations to each other. Four areas of groundwater recharge to the study area were identified based on groundwater elevations, hydrogeologic characteristics, and geochemical and isotopic evidence. One source of recharge enters the study area from the saturated alluvial deposits underlying the South Fork of the Puerco River to the north of the study area. A second source of recharge is shown to originate from a leaky cistern containing production water from the San Andres-Glorieta aquifer. The other two sources of recharge are shown to enter the study area from the south: one from an arroyo valley draining an area to the south and one from hill-front recharge that passes under the reported release of perchlorate and explosive constituents. The spatial extent and interaction of groundwater originating from these various sources along identified flow paths affect the persistence and attenuation of constituents of concern. It was determined that groundwater originating in the area of a former explosives’ wash-out operation and an

  12. Altitude of the water table in the alluvial and other shallow aquifers along the Colorado River near La Grange, Texas, December 1980

    USGS Publications Warehouse

    Rettman, Paul

    1981-01-01

    The delineation of the water table in the alluvium of the Colorado River is fairly well defined, and 10-feet contour intervals may be interpreted with confidence in the area called ' potential lignite-mining area. ' The water table in the bedrock aquifers is more difficult to delineate with the available data; therefore, the contours are only estimates of the position of the water table in the hilly bedrock area adjacent to the Colorado River alluvium. 

  13. Identification of recharge zones in the lower Mississippi River alluvial aquifer using high-resolution precipitation estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water resources in the lower Mississippi River alluvial valley play a critical role in agricultural productivity due to the widespread use of irrigation during the growing season. However, the unknown specifics of surface-atmosphere feedbacks in the region, along with diminishing groundwater availa...

  14. Evaluation of hydrologic conditions and nitrate concentrations in the Rio Nigua de Salinas alluvial fan aquifer, Salinas, Puerto Rico, 2002-03

    USGS Publications Warehouse

    Rodriguez, Jose M.

    2006-01-01

    A ground-water quality study to define the potential sources and concentration of nitrate in the Rio Nigua de Salinas alluvial fan aquifer was conducted between January 2002 and March 2003. The study area covers about 3,600 hectares of the coastal plain within the municipality of Salinas in southern Puerto Rico, extending from the foothills to the Caribbean Sea. Agriculture is the principal land use and includes cultivation of diverse crops, turf grass, bioengineered crops for seed production, and commercial poultry farms. Ground-water withdrawal in the alluvial fan was estimated to be about 43,500 cubic meters per day, of which 49 percent was withdrawn for agriculture, 42 percent for public supply, and 9 percent for industrial use. Ground-water flow in the study area was primarily to the south and toward a cone of depression within the south-central part of the alluvial fan. The presence of that cone of depression and a smaller one located in the northeastern quadrant of the study area may contribute to the increase in nitrate concentration within a total area of about 545 hectares by 'recycling' ground water used for irrigation of cultivated lands. In an area that covers about 405 hectares near the center of the Salinas alluvial fan, nitrate concentrations increased from 0.9 to 6.7 milligrams per liter as nitrogen in 1986 to 8 to 12 milligrams per liter as nitrogen in 2002. Principal sources of nitrate in the study area are fertilizers (used in the cultivated farmlands) and poultry farm wastes. The highest nitrogen concentrations were found at poultry farms in the foothills area. In the area of disposed poultry farm wastes, nitrate concentrations in ground water ranged from 25 to 77 milligrams per liter as nitrogen. Analyses for the stable isotope ratios of nitrogen-15/nitrogen-14 in nitrate were used to distinguish the source of nitrate in the coastal plain alluvial fan aquifer. Potential nitrate loads from areas under cultivation were estimated for the

  15. Summary of hydraulic properties of the Floridan Aquifer system in coastal Georgia and adjacent parts of South Carolina and Florida

    USGS Publications Warehouse

    Clarke, John S.; Leeth, David C.; Taylor-Harris, DaVette; Painter, Jaime A.; Labowski, James L.

    2005-01-01

    Hydraulic-property data for the Floridan aquifer system and equivalent clastic sediments in a 67-county area of coastal Georgia and adjacent parts of South Carolina and Florida were evaluated to provide data necessary for development of ground-water flow and solute-transport models. Data include transmissivity at 324 wells, storage coefficient at 115 wells, and vertical hydraulic conductivity of 72 core samples from 27 sites. Hydraulic properties of the Upper Floridan aquifer vary greatly in the study area due to the heterogeneity (and locally to anisotropy) of the aquifer and to variations in the degree of confinement provided by confining units. Prominent structural features in the areathe Southeast Georgia Embayment, the Beaufort Arch, and the Gulf Troughinfluence the thickness and hydraulic properties of the sediments comprising the Floridan aquifer system. Transmissivity of the Upper Floridan aquifer and equivalent updip units was compiled for 239 wells and ranges from 530 feet squared per day (ft2/d) at Beaufort County, South Carolina, to 600,000 ft2/d in Coffee County, Georgia. In carbonate rock settings of the lower Coastal Plain, transmissivity of the Upper Floridan aquifer generally is greater than 20,000 ft2/d, with values exceeding 100,000 ft2/d in the southeastern and southwestern parts of the study area (generally coinciding with the area of greatest aquifer thickness). Transmissivity of the Upper Floridan aquifer generally is less than 10,000 ft2/d in and near the upper Coastal Plain, where the aquifer is thin and consists largely of clastic sediments, and in the vicinity of the Gulf Trough, where the aquifer consists of low permeability rocks and sediments. Large variability in the range of transmissivity in Camden and Glynn Counties, Georgia, and Nassau County, Florida, demonstrates the anisotropic distribution of hydraulic properties that may result from fractures or solution openings in the carbonate rocks. Storage coefficient of the Upper

  16. Quality of shallow ground water in alluvial aquifers of the Williamette Basin, Oregon, 1993-95. National water-quality assessment program. Water-resources investigations

    SciTech Connect

    Hinkle, S.R.

    1997-12-31

    The purposes of this report are to describe the quality of shallow ground water in alluvial aquifers of the Willamette Basin and to identify relationships between shallow ground-water quality and various natural and anthropogenic factors. Several natural and anthropogenic factors (soil characteristics, cumulative thickness of clay above open interval of well, surficial geology, and land use) were evaluated because of the potential for these factors to either control or be related to contaminant occurrence and spatial distribution. Spatial distributions of nitrite plus nitrate, phosphorous, pesticides and pesticide degradation products, volatile organic compounds (VOCs), trace elements (primarily arsenic, a trace element of local concern), and radon were evaluated for 1993-95. Ancillary chemical data--nitrite, chloride, tritium (H-3), and dissolved-oxygen (DO) concentrations--also are presented.

  17. Hydrologic, lithologic, and chemical data for sediment in the shallow alluvial aquifer at two sites near Fallon, Churchill County, Nevada, 1984-85

    USGS Publications Warehouse

    Lico, M.S.; Welch, A.H.; Hughes, J.L.

    1986-01-01

    The U.S. Geological Survey collected an extensive amount of hydrogeologic data from the shallow alluvial aquifer at two study sites near Fallon, Nevada, from 1984 though 1985. These data were collected as part of a study to determine the geochemical controls on the mobility of arsenic and other trace elements in shallow groundwater systems. The main study area is approximately 7 miles south of Fallon. A subsidiary study area is about 8 miles east of Fallon. The data collected include lithologic logs and water level altitudes for the augered sampling wells and piezometers, and determinations of arsenic and selenium content, grain size, porosity, hydraulic conductivity, and mineralogy for sediment samples from cores. (USGS)

  18. Status of Water Levels and Selected Water-Quality Conditions in the Mississippi River Valley Alluvial Aquifer in Eastern Arkansas, 2004

    USGS Publications Warehouse

    Schrader, T.P.

    2006-01-01

    During the spring of 2004, water levels were measured in 684 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. Ground-water levels are affected by intense ground-water withdrawals resulting in extensive potentiometric depressions. In 2004, the highest water-level altitude measured was 293 feet above National Geodetic Vertical Datum of 1929 in northeastern Clay County. The lowest water-level altitude measured was 76 feet above National Geodetic Vertical Datum of 1929 in the center of Arkansas County. A large depression in the potentiometric surface was located in Arkansas, Lonoke, and Prairie Counties during 1998 and persisted to 2002. The area enclosed in the 100-foot contour in Arkansas County in 2004 is about the same as in 2002, however, the area enclosed in the 100-foot contour in Lonoke and Prairie Counties in 2004 has receded. Two shallower cones of depressions were located in Craighead, Cross, and Poinsett Counties and St. Francis, Woodruff, Lee, and Monroe Counties west of Crowleys Ridge during 1998. The 2004 potentiometricsurface map shows that the areas enclosed by the 140-foot contour have continued to expand. A map of changes in water-level measurements between 2000 and 2004 was constructed using the difference between water-level measurements from 625 wells reported in this report and the 2000 Mississippi River Valley alluvial aquifer report. Water-level changes between 2000 and 2004 ranged from -31.1 feet to 16.3 feet, with a mean of -0.7 feet (negative changes indicating water-level declines, positive changes indicating water-level rises). The largest rise of 16.3 feet is in Arkansas County and the largest decline of -31.1 feet is in Prairie County. Long-term water-level changes were calculated for 134 wells in the alluvial aquifer for the period from 1980 to 2004. The mean annual decline in water level for the entire study area was -0.31 feet per year with a range of -1.35 feet per year to 0.84 feet per year. The

  19. Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

    NASA Astrophysics Data System (ADS)

    Owen, D. Des. R.; Shouakar-Stash, O.; Morgenstern, U.; Aravena, R.

    2016-08-01

    Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (‑58‰ to ‑49‰) and shallow coal measures underlying the alluvium (‑80‰ to ‑65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (<310‰) indicate acetoclastic methanogenesis where SO4 concentrations inhibit CO2 reduction. Evidence of CH4 migration from the deep gas reservoir (200–500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins.

  20. Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

    PubMed Central

    Owen, D. Des. R.; Shouakar-Stash, O.; Morgenstern, U.; Aravena, R.

    2016-01-01

    Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (−58‰ to −49‰) and shallow coal measures underlying the alluvium (−80‰ to −65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (<310‰) indicate acetoclastic methanogenesis where SO4 concentrations inhibit CO2 reduction. Evidence of CH4 migration from the deep gas reservoir (200–500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins. PMID:27578542

  1. Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea).

    PubMed

    Kim, Kyoung-Ho; Yun, Seong-Taek; Choi, Byoung-Young; Chae, Gi-Tak; Joo, Yongsung; Kim, Kangjoo; Kim, Hyoung-Soo

    2009-07-21

    Hydrochemical and multivariate statistical interpretations of 16 physicochemical parameters of 45 groundwater samples from a riverside alluvial aquifer underneath an agricultural area in Osong, central Korea, were performed in this study to understand the spatial controls of nitrate concentrations in terms of biogeochemical processes occurring near oxbow lakes within a fluvial plain. Nitrate concentrations in groundwater showed a large variability from 0.1 to 190.6 mg/L (mean=35.0 mg/L) with significantly lower values near oxbow lakes. The evaluation of hydrochemical data indicated that the groundwater chemistry (especially, degree of nitrate contamination) is mainly controlled by two competing processes: 1) agricultural contamination and 2) redox processes. In addition, results of factorial kriging, consisting of two steps (i.e., co-regionalization and factor analysis), reliably showed a spatial control of the concentrations of nitrate and other redox-sensitive species; in particular, significant denitrification was observed restrictedly near oxbow lakes. The results of this study indicate that sub-oxic conditions in an alluvial groundwater system are developed geologically and geochemically in and near oxbow lakes, which can effectively enhance the natural attenuation of nitrate before the groundwater discharges to nearby streams. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  2. Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea)

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Ho; Yun, Seong-Taek; Choi, Byoung-Young; Chae, Gi-Tak; Joo, Yongsung; Kim, Kangjoo; Kim, Hyoung-Soo

    2009-07-01

    Hydrochemical and multivariate statistical interpretations of 16 physicochemical parameters of 45 groundwater samples from a riverside alluvial aquifer underneath an agricultural area in Osong, central Korea, were performed in this study to understand the spatial controls of nitrate concentrations in terms of biogeochemical processes occurring near oxbow lakes within a fluvial plain. Nitrate concentrations in groundwater showed a large variability from 0.1 to 190.6 mg/L (mean = 35.0 mg/L) with significantly lower values near oxbow lakes. The evaluation of hydrochemical data indicated that the groundwater chemistry (especially, degree of nitrate contamination) is mainly controlled by two competing processes: 1) agricultural contamination and 2) redox processes. In addition, results of factorial kriging, consisting of two steps (i.e., co-regionalization and factor analysis), reliably showed a spatial control of the concentrations of nitrate and other redox-sensitive species; in particular, significant denitrification was observed restrictedly near oxbow lakes. The results of this study indicate that sub-oxic conditions in an alluvial groundwater system are developed geologically and geochemically in and near oxbow lakes, which can effectively enhance the natural attenuation of nitrate before the groundwater discharges to nearby streams. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  3. A reconnaissance water-quality appraisal of the Fountain Creek alluvial aquifer between Colorado Springs and Pueblo, Colorado, including trace elements and organic constituents

    USGS Publications Warehouse

    Cain, Doug; Edelmann, Patrick

    1986-01-01

    This report describes the hydrology and chemical quality of water in the stream-aquifer system along Fountain Creek and relates groundwater quality to land use, water use, and wastewater discharges. The alluvial aquifer, which is underlain by shale bedrock, is transmissive, extensively pumped, and primarily is recharged by Fountain Creek and irrigation-return flow. Groundwater flows south about 20 ft/day, average residence time is less than 10 yr. Land use primarily is urban in the northern one-third and agricultural in the southern two-thirds of the area. Major ions, boron, iron, lithium, selenium, strontium, and uranium increased in concentration downgradient. The largest concentrations of nitrogen and detergents were in the northern end of the area because of recharge of sewage effluent in Fountain Creek. Other trace elements usually were present in concentrations less than 20 mg/L. Volatile organic compounds were detected in water from 11 of 20 wells sampled. Samples from 4 of the 20 wells were analyzed for semivolatile organics using a closed-loop stripping technique, which detected additional compounds at nanogram/L concentrations. (USGS)

  4. Evaluation of the groundwater-flow model for the Ohio River alluvial aquifer near Carrollton, Kentucky, updated to conditions in September 2010

    USGS Publications Warehouse

    Unthank, Michael D.

    2013-01-01

    The Ohio River alluvial aquifer near Carrollton, Ky., is an important water resource for the cities of Carrollton and Ghent, as well as for several industries in the area. The groundwater of the aquifer is the primary source of drinking water in the region and a highly valued natural resource that attracts various water-dependent industries because of its quantity and quality. This report evaluates the performance of a numerical model of the groundwater-flow system in the Ohio River alluvial aquifer near Carrollton, Ky., published by the U.S. Geological Survey in 1999. The original model simulated conditions in November 1995 and was updated to simulate groundwater conditions estimated for September 2010. The files from the calibrated steady-state model of November 1995 conditions were imported into MODFLOW-2005 to update the model to conditions in September 2010. The model input files modified as part of this update were the well and recharge files. The design of the updated model and other input files are the same as the original model. The ability of the updated model to match hydrologic conditions for September 2010 was evaluated by comparing water levels measured in wells to those computed by the model. Water-level measurements were available for 48 wells in September 2010. Overall, the updated model underestimated the water levels at 36 of the 48 measured wells. The average difference between measured water levels and model-computed water levels was 3.4 feet and the maximum difference was 10.9 feet. The root-mean-square error of the simulation was 4.45 for all 48 measured water levels. The updated steady-state model could be improved by introducing more accurate and site-specific estimates of selected field parameters, refined model geometry, and additional numerical methods. Collection of field data to better estimate hydraulic parameters, together with continued review of available data and information from area well operators, could provide the model with

  5. Potentiometric surface of the Floridan Aquifer, Southwest Florida Water Management District and adjacent areas, September 1978

    USGS Publications Warehouse

    Wolansky, R.M.; Mills, L.R.; Woodham, W.M.; Laughlin, C.P.

    1978-01-01

    A September 1978 potentiometric-surface map depicts the annual high water-level period of the Floridan aquifer in the Southwest Florida Management District. Potentiometric levels increased 10 to 25 feet between May 1978 and September 1978, in the citrus and farming sections of southern Hillsborough, northern Hardee, southwestern Polk and Manatee Counties. These areas are widely affected by pumping for irrigation and have the greatest fluctuations in water-levels between the low and high water-level periods. Water-level rises in coastal, northern and southern areas of the Water Management District ranged from 0 to 10 feet. (Woodard-USGS)

  6. Occurrence and distribution of nitrate and herbicides in the Iowa River alluvial aquifer, Iowa; May 1984 to November 1985

    USGS Publications Warehouse

    Detroy, M.G.; Kuzniar, R.L.

    1988-01-01

    For nested wells, the seasonal variations of nitrate and herbicides were greater at the shallower sampling depths for domestic and test wells. Seasonal variations of nitrate and herbicides illustrate that these constituents move quickly from surface application to shallow underlying aquifers. These constituents can be detected in ground water soon after chemical applications, usually within 6 weeks.

  7. Influence of colloids on the attenuation and transport of phosphorus in alluvial gravel aquifer and vadose zone media.

    PubMed

    Pang, Liping; Lafogler, Mark; Knorr, Bastian; McGill, Erin; Saunders, Darren; Baumann, Thomas; Abraham, Phillip; Close, Murray

    2016-04-15

    Phosphorous (P) leaching (e.g., from effluents, fertilizers) and transport in highly permeable subsurface media can be an important pathway that contributes to eutrophication of receiving surface waters as groundwater recharges the base-flow of surface waters. Here we investigated attenuation and transport of orthophosphate-P in gravel aquifer and vadose zone media in the presence and absence of model colloids (Escherichia coli, kaolinite, goethite). Experiments were conducted using repacked aquifer media in a large column (2m long, 0.19m in diameter) and intact cores (0.4m long, 0.24m in diameter) of vadose zone media under typical field flow rates. In the absence of the model colloids, P was readily traveled through the aquifer media with little attenuation (up to 100% recovery) and retardation, and P adsorption was highly reversible. Conversely, addition of the model colloids generally resulted in reduced P concentration and mass recovery (down to 28% recovery), and increased retardation and adsorption irreversibility in both aquifer and vadose zone media. The degree of colloid-assisted P attenuation was most significant in the presence of fine material and Fe-containing colloids at low flow rate but was least significant in the presence of coarse gravels and E. coli at high flow rate. Based on the experimental results, setback distances of 49-53m were estimated to allow a reduction of P concentrations in groundwater to acceptable levels in the receiving water. These estimates were consistent with field observations in the same aquifer media. Colloid-assisted P attenuation can be utilized to develop mitigation strategies to better manage effluent applications in gravelly soils. To efficiently retain P within soil matrix and reduce P leaching to groundwater, it is recommended to select soils that are rich in iron oxides, to periodically disturb soil preferential flow paths by tillage, and to apply a low irrigation rate.

  8. Estimating the uncertainty of the impact of climate change on alluvial aquifers. Case study in central Italy

    NASA Astrophysics Data System (ADS)

    Romano, Emanuele; Camici, Stefania; Brocca, Luca; Moramarco, Tommaso; Pica, Federico; Preziosi, Elisabetta

    2014-05-01

    There is evidence that the precipitation pattern in Europe is trending towards more humid conditions in the northern region and drier conditions in the southern and central-eastern regions. However, a great deal of uncertainty concerns how the changes in precipitations will have an impact on water resources, particularly on groundwater, and this uncertainty should be evaluated on the basis of that coming from 1) future climate scenarios of Global Circulation Models (GCMs) and 2) modeling chains including the downscaling technique, the infiltration model and the calibration/validation procedure used to develop the groundwater flow model. With the aim of quantifying the uncertainty of these components, the Valle Umbra porous aquifer (Central Italy) has been considered as a case study. This aquifer, that is exploited for human consumption and irrigation, is mainly fed by the effective infiltration from the ground surface and partly by the inflow from the carbonate aquifers bordering the valley. A numerical groundwater flow model has been developed through the finite difference MODFLOW2005 code and it has been calibrated and validated considering the recharge regime computed through a Thornthwaite-Mather infiltration model under the climate conditions observed in the period 1956-2012. Future scenarios (2010-2070) of temperature and precipitation have been obtained from three different GMCs: ECHAM-5 (Max Planck Institute, Germany), PCM (National Centre Atmospheric Research) and CCSM3 (National Centre Atmospheric Research). Each scenario has been downscaled (DSC) to the data of temperature and precipitation collected in the baseline period 1960-1990 at the stations located in the study area through two different statistical techniques (linear rescaling and quantile mapping). Then, stochastic rainfall and temperature time series are generated through the Neyman-Scott Rectangular Pulses model (NSRP) for precipitation and the Fractionally Differenced ARIMA model (FARIMA

  9. Aquifer systems in the Great Basin region of Nevada, Utah, and adjacent states; a study plan

    USGS Publications Warehouse

    Harrill, James R.; Welch, A.H.; Prudic, D.E.; Thomas, J.M.; Carman, R.L.; Plume, R.W.; Gates, J.S.; Mason, J.L.

    1983-01-01

    The Great Basin Regional Aquifer Study includes about 140,000 square miles in parts of Nevada, Utah, California, Idaho, Oregon , and Arizona within which 240 hydrographic areas occupy structural depressions formed primarily by basin-and-range faulting. The principal aquifers are in basin-fill deposits; however, significant carbonate-rock aquifers underlie much of eastern Nevada and western Utah. In October 1980, the U.S. Geological Survey started a 4-year study to: (1) describe the ground-water systems, (2) analyze the changes that have led to the systems ' present conditions, (3) tie the results of this and previous studies together in a regional analysis, and (4) provide means by which effects of future ground-water development can be estimated. A plan of work is presented that describes the general approach to be taken. It defines the major tasks necessary to meet objectives and defines constraints on the scope of work. The approach has been influenced by the diverse nature of ground water flow systems and the large number of basins. A detailed appraisal of 240 individual areas would require more resources than are available. Consequently, the general approach is to study selected ' typical ' areas and key hydrologic processes. Effort during the first three years will be directed toward describing the regional hydrology, conducting detailed studies of ' type ' areas and studying selected hydrologic processes. Effort during the final year will be directed toward developing a regional analysis of results. Special studies will include evaluation of regional geochemistry , regional hydrogeology, recharge, ground-water discharge, and use of remote sensing. Areas to be studied using ground-water flow models include the regional carbonate-rock province in eastern Nevada and western Utah, six valleys--Las Vegas, Carson, Paradise, Dixie, Smith Creek, and Stagecoach--Nevada, plus Jordan Valley, the Millford area, and Tule Valley in Utah. The results will be presented in a

  10. Intrinsic biodegradation potential of aromatic hydrocarbons in an alluvial aquifer--potentials and limits of signature metabolite analysis and two stable isotope-based techniques.

    PubMed

    Morasch, Barbara; Hunkeler, Daniel; Zopfi, Jakob; Temime, Brice; Höhener, Patrick

    2011-10-01

    Three independent techniques were used to assess the biodegradation of monoaromatic hydrocarbons and low-molecular weight polyaromatic hydrocarbons in the alluvial aquifer at the site of a former cokery (Flémalle, Belgium). Firstly, a stable carbon isotope-based field method allowed quantifying biodegradation of monoaromatic compounds in situ and confirmed the degradation of naphthalene. No evidence could be deduced from stable isotope shifts for the intrinsic biodegradation of larger molecules such as methylnaphthalenes or acenaphthene. Secondly, using signature metabolite analysis, various intermediates of the anaerobic degradation of (poly-) aromatic and heterocyclic compounds were identified. The discovery of a novel metabolite of acenaphthene in groundwater samples permitted deeper insights into the anaerobic biodegradation of almost persistent environmental contaminants. A third method, microcosm incubations with 13C-labeled compounds under in situ-like conditions, complemented techniques one and two by providing quantitative information on contaminant biodegradation independent of molecule size and sorption properties. Thanks to stable isotope labels, the sensitivity of this method was much higher compared to classical microcosm studies. The 13C-microcosm approach allowed the determination of first-order rate constants for 13C-labeled benzene, naphthalene, or acenaphthene even in cases when degradation activities were only small. The plausibility of the third method was checked by comparing 13C-microcosm-derived rates to field-derived rates of the first approach. Further advantage of the use of 13C-labels in microcosms is that novel metabolites can be linked more easily to specific mother compounds even in complex systems. This was achieved using alluvial sediments where 13C-acenaphthyl methylsuccinate was identified as transformation product of the anaerobic degradation of acenaphthene.

  11. Metatranscriptomic evidence of pervasive and diverse chemolithoautotrophy relevant to C, S, N and Fe cycling in a shallow alluvial aquifer

    PubMed Central

    Jewell, Talia N M; Karaoz, Ulas; Brodie, Eoin L; Williams, Kenneth H; Beller, Harry R

    2016-01-01

    Groundwater ecosystems are conventionally thought to be fueled by surface-derived allochthonous organic matter and dominated by heterotrophic microbes living under often-oligotrophic conditions. However, in a 2-month study of nitrate amendment to a perennially suboxic aquifer in Rifle (CO), strain-resolved metatranscriptomic analysis revealed pervasive and diverse chemolithoautotrophic bacterial activity relevant to C, S, N and Fe cycling. Before nitrate injection, anaerobic ammonia-oxidizing (anammox) bacteria accounted for 16% of overall microbial community gene expression, whereas during the nitrate injection, two other groups of chemolithoautotrophic bacteria collectively accounted for 80% of the metatranscriptome: (1) members of the Fe(II)-oxidizing Gallionellaceae family and (2) strains of the S-oxidizing species, Sulfurimonas denitrificans. Notably, the proportion of the metatranscriptome accounted for by these three groups was considerably greater than the proportion of the metagenome coverage that they represented. Transcriptional analysis revealed some unexpected metabolic couplings, in particular, putative nitrate-dependent Fe(II) and S oxidation among nominally microaerophilic Gallionellaceae strains, including expression of periplasmic (NapAB) and membrane-bound (NarGHI) nitrate reductases. The three most active groups of chemolithoautotrophic bacteria in this study had overlapping metabolisms that allowed them to occupy different yet related metabolic niches throughout the study. Overall, these results highlight the important role that chemolithoautotrophy can have in aquifer biogeochemical cycling, a finding that has broad implications for understanding terrestrial carbon cycling and is supported by recent studies of geochemically diverse aquifers. PMID:26943628

  12. Characteristics of aquifer hydraulic parameters estimated by PEST using MODFLOW for the Kurobe River Alluvial fan, Japan

    NASA Astrophysics Data System (ADS)

    Tebakari, Taichi; Kita, Ryuhei

    2014-05-01

    The purpose of this study is to improve precision of three dimensional unsteady groundwater flow model using MODFLOW for the Kurobe River alluvial fan, Japan. Groundwater hydraulic parameters (hydraulic conductivity; kx, ky, kz, specific storage;ss and specific yield; sy) were estimated using PEST (Parameter ESTimation) and studied the characteristics of estimated parameters. Hydraulic conductivities (kz) were estimated using 346 observation well data. As a result, maximum hydraulic conductivity was 2.02 cm/s, minimum was 2.24×10-5 cm/s, average was 4.90×10-2 cm/s. As a result of numerical simulation, kz was estimated almost same as observation data. In order to quantitatively and accurately estimate hydraulic conductivity, uniformly location of observation wells was needed.

  13. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes

    USGS Publications Warehouse

    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.

  14. Groundwater infiltration from alluvial aquifer into karstic aquifer - case study of recharge from river I\\vska to Ižica karstic springs

    NASA Astrophysics Data System (ADS)

    Meglič, P.; Brenčič, M.

    2012-04-01

    River I\\vska and Ižica karstic springs are situated in the central part of Slovenia (approximately 20 km south from city Ljubljana) on southern edge of Barje, a tectonic depression field with mostly Holocene and Pleistocene lacustrine and rivers' sediments. Barje is surrounded with hills, which on the southern part consists mostly of Triassic dolomite and Jurassic limestone as well as the basement of Barje in this area. Recharge area of I\\vska River and Ižica karstic springs is covering around 102 km2 of the southern hilly edge of Barje. I\\vska River is a torrent with springs on Blo\\vska planota and flows towards Barje to the north. River formed deep narrow valley that slightly opens at the beginning of I\\vski Vintgar, where flows on a shallow gravel river bed deposited on karstic aquifer. The valley opens on Ljubljansko Barje at village I\\vska vas. Ižica karstic springs are situated on the contact of karst aquifer and Barje intergranular aquifer east of I\\vska valley. After a big flood event on 18th of September 2010 I\\vska River disappeared in the karstic fissures on the river bottom, near bridge in I\\vska village. One day later infiltration point moved 1070 meters upstream. This extreme event caused around 40% higher base flow discharge of Ižica River and total disappearance of I\\vska River for a few days. The analyzed discharge data in the year 2010 of the I\\vska and Ižica River, gave a new understanding of the discharge of I\\vska River and groundwater flow in the area. Before this extreme event discharge of the I\\vska River was measured at different profiles in the channel and reduction of discharge was observed along the course indicating that I\\vska recharges Ižica springs. Analyses presented were performed in the frame of INCOME project and are aimed to improve understanding of hydrogeological conditions in the catchment area of Barje aquifer which is exploited for the public water supply of Ljubljana.

  15. Groundwater recharge to the Gulf Coast aquifer system in Montgomery and Adjacent Counties, Texas

    USGS Publications Warehouse

    Oden, Timothy D.; Delin, Geoffrey N.

    2013-01-01

    Simply stated, groundwater recharge is the addition of water to the groundwater system. Most of the water that is potentially available for recharging the groundwater system in Montgomery and adjacent counties in southeast Texas moves relatively rapidly from land surface to surface-water bodies and sustains streamflow, lake levels, and wetlands. Recharge in southeast Texas is generally balanced by evapotranspiration, discharge to surface waters, and the downward movement of water into deeper parts of the groundwater system; however, this balance can be altered locally by groundwater withdrawals, impervious surfaces, land use, precipitation variability, or climate, resulting in increased or decreased rates of recharge. Recharge rates were compared to the 1971–2000 normal annual precipitation measured Cooperative Weather Station 411956, Conroe, Tex.

  16. Modeling effects of climatological variability and management practices on conservation of groundwater from the Mississippi River Valley Shallow Alluvial Aquifer in the Mississippi Delta region

    NASA Astrophysics Data System (ADS)

    Thornton, Robert Frank

    Ninety-eight percent of water taken from the Mississippi River Shallow Alluvial Aquifer, hereafter referred to as "the aquifer" or "MRVA," is used by the agricultural industry for irrigation. Mississippi Delta agriculture is increasingly using more water from the MRVA and the aquifer has been losing about 300,000 acre-feet per year. This research expands on previous work in which a model was developed that simulates the effects of climatic variability, crop acreage changes, and specific irrigation methods on consequent variations in the water volume of the MRVA. This study corrects an identified problem by replacing total growing season precipitation with an irrigation demand driver based on evaporation and crop coefficients and changing the time scale from the entire growing season to a daily resolution. The calculated irrigation demand, as a climatological driver for the model, captures effective precipitation more precisely than the initial growing season precipitation driver. Predictive equations resulting from regression analyses of measured versus calculated irrigation water use showed R2 and correlations of 0.33 and 0.57, 0.77 and 0.88, 0.71 and 0.84, and 0.68 and 0.82 for cotton, corn, soybeans and rice, respectively. Ninety-five percent of the predicted values fall within a range of + or - about 23,000 acre-feet, an error of about 10-percent. The study also adds an additional conservation strategy through the use of surface water from on-farm reservoirs in lieu of groundwater. Analyses show that climate could provide the entire water need of the plants in 70-percent of the years for corn, 65-percent of the years for soybeans and cotton, and even 5-percent of the years for rice. Storing precipitation in on-farm structures is an effective way to reduce reliance of Delta producers on groundwater. If producers adopted, at a minimum, the 97.5:2.5 ratio suggested management practice, this minimal management strategy could potentially conserve 48-percent, 35

  17. Revised hydrogeologic framework of the Floridan aquifer system in the northern coastal area of Georgia and adjacent parts of South Carolina

    USGS Publications Warehouse

    Williams, Lester J.; Gill, Harold E.

    2010-01-01

    The hydrogeologic framework for the Floridan aquifer system has been revised for eight northern coastal counties in Georgia and five coastal counties in South Carolina by incorporating new borehole geophysical and flowmeter log data collected during previous investigations. Selected well logs were compiled and analyzed to determine the vertical and horizontal continuity of permeable zones that make up the Upper and Lower Floridan aquifers and to define more precisely the thickness of confining beds that separate these aquifers. The updated framework generally conforms to the original framework established by the U.S. Geological Survey in the 1980s except for adjustments made to the internal boundaries of the Upper and Lower Floridan aquifers and the individual permeable zones that compose these aquifers. The revised boundaries of the Floridan aquifer system were mapped by taking into account results from local studies and regional correlations of geologic and hydrogeologic units. Because the revised framework does not match the previous regional framework along all edges, additional work will be needed to expand the framework into adjacent areas. The Floridan aquifer system in the northern coastal region of Georgia and parts of South Carolina can be divided into the Upper and Lower Floridan aquifers, which are separated by a middle confining unit of relatively lower permeability. The Upper Floridan aquifer includes permeable and hydraulically connected carbonate rocks of Oligocene and upper Eocene age that represent the most transmissive part of the aquifer system. The middle confining unit consists of low permeability carbonate rocks that lie within the lower part of the upper Eocene in Beaufort and Jasper Counties, South Carolina, and within the upper to middle parts of the middle Eocene elsewhere. Locally, the middle confining unit contains thin zones that have moderate to high permeability and can produce water to wells that tap them. The Lower Floridan aquifer

  18. Uranium in framboidal pyrite from a naturally bioreduced alluvial sediment.

    PubMed

    Qafoku, Nikolla P; Kukkadapu, Ravi K; McKinley, James P; Arey, Bruce W; Kelly, Shelly D; Wang, Chongmin; Resch, Charles T; Long, Philip E

    2009-11-15

    Samples of a naturally bioreduced, U-contaminated alluvial sediment were characterized with various microscopic and spectroscopic techniques and wet chemical extraction methods. The objective was to investigate U association and interaction with minerals of the sediment. Bioreduced sediment comprises approximately 10% of an alluvial aquifer adjacent to the Colorado River, in Rifle, CO, that was the site of a former U milling operation. Past and ongoing research has demonstrated that bioreduced sediment is elevated in solid-associated U, total organic carbon, and acid-volatile sulfide, and depleted in bioavailable Fe(III) confirming that sulfate and Fe(III) reduction have occurred naturally in the sediment. SEM/EDS analyses demonstrated that framboidal pyrites (FeS(2)) of different sizes ( approximately 10-20 microm in diameter), and of various microcrystal morphology, degree of surface weathering, and internal porosity were abundant in the <53 microm fraction (silt + clay) of the sediment and absent in adjacent sediments that were not bioreduced. SEM-EMPA, XRF, EXAFS, and XANES measurements showed elevated U was present in framboidal pyrite as both U(VI) and U(IV). This result indicates that U may be sequestered in situ under conditions of microbially driven sulfate reduction and pyrite formation. Conversely, such pyrites in alluvial sediments provide a long-term source of U under conditions of slow oxidation, contributing to the persistence of U of some U plumes. These results may also help in developing remedial measures for U-contaminated aquifers.

  19. Geology and ground-water conditions of Clark County Washington, with a description of a major alluvial aquifer along the Columbia River

    USGS Publications Warehouse

    Mundorff, Maurice John

    1964-01-01

    This report presents the results of an investigation of the ground-water resources of the populated parts of Clark County. Yields adequate for irrigation can be obtained from wells inmost farmed areas in Clark County, Wash. The total available supply is sufficient for all foreseeable irrigation developments. In a few local areas aquifers are fine-grained, and yields of individual wells are low. An enormous ground-water supply is available from a major alluvial aquifer underlying the flood plain of the Columbia River in the vicinity of Vancouver, Camas, and Washougal, where the aquifer is recharged, in part, by infiltration from the river. Yields of individual wells are large, ranging to as much as 4,000 gpm (gallons per minute). Clark County lies along the western flank of the Cascade Range. in the structural lowland (Willamette-Puget trough) between those mountains and the Coast Ranges to the west. The area covered by the report includes the urban, the suburban, and most of the agricultural lands in the county. These lands lie on a Series of nearly fiat plains and benches which rise steplike from the level of the Columbia River (a few feet above sea level) to about 800 feet above sea level. Clark County is-drained by the Columbia River (the trunk stream of the Pacific Northwest) and its tributaries. The Columbia River forms the southern and western boundaries of the county. Although the climate of the county is considered to be humid, the precipitation ranging from about 37 to more than 110 inches annually in various parts of the county, the unequal seasonal distribution (about 1.5 inches total for ;July and August in the agricultural area) makes irrigation highly desirable for most .crops and essential for some specialized crops. Consolidated rocks of Eocene to Miocene age, chiefly volcanic lava flows and pyroclastics but including some sedimentary strata, crop out in the foothills of the Cascades in the eastern part of the county and underlie the younger

  20. Effects of land use and hydrogeology on the water quality of alluvial aquifers in eastern Iowa and southern Minnesota, 1997

    USGS Publications Warehouse

    Savoca, Mark E.; Sadorf, Eric M.; Linhart, S. Mike; Akers, Kim K.B.

    2000-01-01

    Factors other than land use may contribute to observed differences in water quality between and within agricultural and urban areas. Nitrate, atrazine, deethylatrazine, and deisopropylatrazine concentrations were significantly higher in shallow wells with sample intervals nearer the water table and in wells with thinner cumulative clay thickness above the sample intervals. These relations suggest that longer flow paths allow for greater residence time and increase opportunities for sorption, degradation, and dispersion, which may contribute to decreases in nutrient and pesticide concentrations with depth. Nitrogen speciation was influenced by redox conditions. Nitrate concentrations were significantly higher in ground water with dissolved-oxygen concentrations in excess of 0.5 milligram per liter. Ammonia concentrations were higher in ground water with dissolved-oxygen concentrations of 0.5 milligram per liter or less; however, this relation was not statistically significant. The amount of available organic matter may limit denitrification rates. Elevated nitrate concentrations (greater than 2.0 mg/L) were significantly related to lower dissolved organic carbon concentrations in water samples from both agricultural and urban areas. A similar relation between nitrate concentrations (in water) and organic carbon concentrations (in aquifer material) also was observed but was not statistically significant.

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

    PubMed

    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

  2. Assessment of the chemical status of the alluvial aquifer in the Aosta Plain: an example of the implementation of the Water Framework Directive in Italy

    NASA Astrophysics Data System (ADS)

    Rotiroti, Marco; Fumagalli, Letizia; Stefania, Gennaro A.; Frigerio, Maria C.; Simonetto, Fulvio; Capodaglio, Pietro; Bonomi, Tullia

    2015-04-01

    The Italian Legislative Decree 30/09 (D.Lgs. 30/09) implements the EU Water Framework Directive (WFD) providing some technical guidelines to assess the chemical status of groundwater bodies. This work presents the estimation of the chemical status of the shallow aquifer in the Aosta Plain (Aosta Valley Region, NW Alpine sector, Italy) on the basis of the D.Lgs. 30/09. The study area covers ~40 km2 along the Dora Baltea River basin. The Aosta Plain hosts an alluvial aquifer formed of lacustrine, glacial, fluvio-glacial and fan deposits of Pleistocene and Holocene ages. The unconfined aquifer features a depth of ~80 m in the western part of the plain and ~20 in the eastern part due to the intercalation of a silty lacustrine layer. The aquifer is mainly recharged by precipitation, surface water and ice and snow melt. Previous studies revealed that SO4, Fe, Mn, Ni, Cr(VI) and PCE represent potential threats for groundwater quality in the Aosta Plain. The chemical status was calculated using the data collected during the 2012 by the Regional Environmental Protection Agency of the Aosta Valley Region from its groundwater quality monitoring network that includes 38 points. Each point was sampled up to four times. Since the D.Lgs. 30/09 excludes Fe and Mn from the assessment of the groundwater chemical status, the present work deals with SO4, Ni, Cr(VI) and PCE. Threshold values (TVs) were estimated on the basis of natural background levels (NBLs) for SO4, Ni and Cr(VI) whereas, for PCE, the reference value (REF) reported by the D.Lgs. 30/09 (i.e., 1.1 µg/L) was used as TV. The NBLs were calculated using the two approaches suggested by the EU research project BRIDGE, that are the pre-selection and the component separation. The TVs were evaluated using the following criteria: (a) if NBL < REF, then TV = (REF+NBL)/2 and (b) if NBL ≥ REF, then TV = NBL. The average between the NBL resulted from the pre-selection and the component separation was used in the TV estimation

  3. Contributing recharge areas, groundwater travel time, and groundwater water quality of the Missouri River alluvial aquifer near the City of Independence, Missouri, well field, 1997-2008

    USGS Publications Warehouse

    Kelly, Brian P.

    2011-01-01

    The City of Independence, Missouri, operates a well field in the Missouri River alluvial aquifer. Contributing recharge areas (CRA) were last determined for the well field in 1996. Since that time, eight supply wells have been installed in the area north of the Missouri River and well pumpage has changed for the older supply wells. The change in pumping has altered groundwater flow and substantially changed the character of the CRA and groundwater travel times to the supply wells. The U.S Geological Survey, in a cooperative study with the City of Independence, Missouri, simulated steady-state groundwater flow for 2007 well pumpage, average annual river stage, and average annual recharge. Particle-tracking analysis was used to determine the CRA for supply wells and monitoring wells, and the travel time from recharge areas to supply wells, recharge areas to monitoring wells, and monitoring wells to supply wells. The simulated CRA for the well field is elongated in the upstream direction and extends to both sides of the Missouri River. Groundwater flow paths and recharge areas estimated for monitoring wells indicate the origin of water to each monitoring well, the travel time of that water from the recharge area, the flow path from the vicinity of each monitoring well to a supply well, and the travel time from the monitoring well to the supply well. Monitoring wells 14a and 14b have the shortest groundwater travel time from their contributing recharge area of 0.30 years and monitoring well 29a has the longest maximum groundwater travel time from its contributing recharge area of 1,701 years. Monitoring well 22a has the shortest groundwater travel time of 0.5 day to supply well 44 and monitoring well 3b has the longest maximum travel time of 31.91 years to supply well 10. Water-quality samples from the Independence groundwater monitoring well network were collected from 1997 to 2008 by USGS personnel during ongoing annual sampling within the 10-year contributing

  4. Evaluation of Selected Model Constraints and Variables on Simulated Sustainable Yield from the Mississippi River Valley Alluvial Aquifer System in Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.

    2008-01-01

    An existing conjunctive use optimization model of the Mississippi River Valley alluvial aquifer was used to evaluate the effect of selected constraints and model variables on ground-water sustainable yield. Modifications to the optimization model were made to evaluate the effects of varying (1) the upper limit of ground-water withdrawal rates, (2) the streamflow constraint associated with the White River, and (3) the specified stage of the White River. Upper limits of ground-water withdrawal rates were reduced to 75, 50, and 25 percent of the 1997 ground-water withdrawal rates. As the upper limit is reduced, the spatial distribution of sustainable pumping increases, although the total sustainable pumping from the entire model area decreases. In addition, the number of binding constraint points decreases. In a separate analysis, the streamflow constraint associated with the White River was optimized, resulting in an estimate of the maximum sustainable streamflow at DeValls Bluff, Arkansas, the site of potential surface-water withdrawals from the White River for the Grand Prairie Area Demonstration Project. The maximum sustainable streamflow, however, is less than the amount of streamflow allocated in the spring during the paddlefish spawning period. Finally, decreasing the specified stage of the White River was done to evaluate a hypothetical river stage that might result if the White River were to breach the Melinda Head Cut Structure, one of several manmade diversions that prevents the White River from permanently joining the Arkansas River. A reduction in the stage of the White River causes reductions in the sustainable yield of ground water.

  5. Sorption and mineralization of S-metolachlor and its ionic metabolites in soils and vadose zone solids: consequences on groundwater quality in an alluvial aquifer (Ain Plain, France).

    PubMed

    Baran, Nicole; Gourcy, Laurence

    2013-11-01

    This study characterizes the transfer of S-metolachlor (SMOC) and its metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA) to the alluvial aquifer. Sorption and mineralization of SMOC and its two ionic metabolites were characterized for cultivated soils and solids from the vadose (unsaturated) zone in the Ain Plain (France). Under sterile soil conditions, the absence of mineralization confirms the importance of biotic processes in SMOC degradation. There is some adsorption and mineralization of the parent molecule and its metabolites in the unsaturated zone, though less than in soils. For soils, the MESA adsorption constant is statistically higher than that of MOXA and the sorption constants of the two metabolites are significantly lower than that of SMOC. After 246 days, for soils, maximums of 26% of the SMOC, 30% of the MESA and 38% of the MOXA were mineralized. This partly explains the presence of these metabolites in the groundwater at concentrations generally higher than those of the parent molecule for MESA, although there is no statistical difference in the mineralization of the 3 molecules. The laboratory results make it possible to explain the field observations made during 27 months of groundwater quality monitoring (monthly sampling frequency). The evolution of both metabolite concentrations in the groundwater is directly related to recharge dynamics; there is a positive correlation between concentrations and the groundwater level. The observed lag of several months between the signals of the parent molecule and those of the metabolites is probably due to greater sorption of the parent molecule than of its metabolites and/or to degradation kinetics.

  6. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 17. Geomorphology of the Red River Valley, Taos County, New Mexico, and Influence on Ground-Water Flow in the Shallow Alluvial Aquifer

    USGS Publications Warehouse

    Vincent, Kirk R.

    2008-01-01

    In April 2001, the U.S. Geological Survey (USGS) and the New Mexico Environment Department (NMED) began a cooperative study to infer the pre-mining ground-water chemistry at the Molycorp molybdenum mine site in the Red River Valley of north-central New Mexico. This report is one in a series of reports that can be used to determine pre-mining ground-water conditions at the mine site. Molycorp?s Questa molybdenum mine in the Red River Valley, northern New Mexico, is located near the margin of the Questa caldera in a highly mineralized region. The bedrock of the Taos Range surrounding the Red River is composed of Proterozoic rocks of various types, which are intruded and overlain by Oligocene volcanic rocks associated with the Questa caldera. Locally, these rocks were altered by hydrothermal activity. The alteration zones that contain sulfide minerals are particularly important because they constitute the commercial ore bodies of the region and, where exposed to weathering, form sites of rapid erosion referred to as alteration scars. Over the past thousand years, if not over the entire Holocene, erosion rates were spatially variable. Forested hillslopes eroded at about 0.04 millimeter per year, whereas alteration scars eroded at about 2.7 millimeters per year. The erosion rate of the alteration scars is unusually rapid for naturally occurring sites that have not been disturbed by humans. Watersheds containing large alteration scars delivered more sediment to the Red River Valley than the Red River could remove. Consequently, large debris fans, as much as 80 meters thick, developed within the valley. The geomorphology of the Red River Valley has had several large influences on the hydrology of the shallow alluvial aquifer, and those influences were in effect before the onset of mining within the watershed. Several reaches where alluvial ground water emerges to become Red River streamflow were observed by a tracer dilution study conducted in 2001. The aquifer narrows

  7. Évolution spatio-temporelle d'un aquifère alluvial sous l'effet d'une sécheresse pluriannuelle exceptionnelle (littoral Méditerranéen, Hérault, France)

    NASA Astrophysics Data System (ADS)

    Grillot, J. C.; Razack, M.

    1985-11-01

    The potentiometric-surface fluctuations and hydrochemical evolution of an alluvial aquifer located along the Mediterranean shore have been observed during a period including a multi-year drought. The ions selected for this study are chloride and sulfate for the following reasons: (1) nearness of the sea-shore; and (2) a social and economical local context based upon an intensive polyculture which requires application of sulfur over more than 90% of the area. Two major conclusions are drawn from this study. (1) The water-level fluctuations indicate different hydrodynamical behaviour of the aquifer, probably depending on vertical zoning of permeability. The alluvial aquifer behaves as multilayered with different permeabilities, which produces potentiometric distortions. (2) From a hydrochemical viewpoint, lagged dilution was observed for choride and sulfate. The question of retention of the chloride by clays has not yet been clearly answered. We interpret the phenomena of lagged dilution as resulting from spatial variations of permeability of the reservoir rather than only from the geochemical nature of its heterogeneities.

  8. Evaluation of the effects of precipitation on ground-water levels from wells in selected alluvial aquifers in Utah and Arizona, 1936-2005

    USGS Publications Warehouse

    Gardner, Philip M.; Heilweil, Victor M.

    2009-01-01

    Increased withdrawals from alluvial aquifers of the southwestern United States during the last half-century have intensified the effects of drought on ground-water levels in valleys where withdrawal for irrigation is greatest. Furthermore, during wet periods, reduced withdrawals coupled with increased natural recharge cause rising ground-water levels. In order to manage water resources more effectively, analysis of ground-water levels under the influence of natural and anthropogenic stresses is useful. This report evaluates the effects of precipitation patterns on ground-water levels in areas of Utah and Arizona that have experienced different amounts of ground-water withdrawal. This includes a comparison of water-level records from basins that are hydrogeologically and climatologically similar but have contrasting levels of ground-water development. Hydrologic data, including records of ground-water levels, basin-wide annual ground-water withdrawals, and precipitation were examined from two basins in Utah (Milford and central Sevier) and three in Arizona (Aravaipa Canyon, Willcox, and Douglas). Most water-level records examined in this study from basins experiencing substantial ground-water development (Milford, Douglas, and Willcox) showed strong trends of declining water levels. Other water-level records, generally from the less-developed basins (central Sevier and Aravaipa Canyon) exhibited trends of increasing water levels. These trends are likely the result of accumulating infiltration of unconsumed irrigation water. Water-level records that had significant trends were detrended by subtraction of a low-order polynomial in an attempt to eliminate the variation in the water-level records that resulted from ground-water withdrawal or the application of water for irrigation. After detrending, water-level residuals were correlated with 2- to 10-year moving averages of annual precipitation from representative stations for the individual basins. The water

  9. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas, 1918-1998, with simulations of water levels caused by projected ground-water withdrawals through 2049

    USGS Publications Warehouse

    Reed, Thomas B.

    2003-01-01

    A digital model of the Mississippi River Valley alluvial aquifer in eastern Arkansas was used to simulate ground-water flow for the period from 1918 to 2049. The model results were used to evaluate effects on water levels caused by demand for ground water from the alluvial aquifer, which has increased steadily for the last 40 years. The model results showed that water currently (1998) is being withdrawn from the aquifer at rates greater than what can be sustained for the long term. The saturated thickness of the alluvial aquifer has been reduced in some areas resulting in dry wells, degraded water quality, decreased water availability, increased pumping costs, and lower well yields. The model simulated the aquifer from a line just north of the Arkansas-Missouri border to south of the Arkansas River and on the east from the Mississippi River westward to the less permeable geologic units of Paleozoic age. The model consists of 2 layers, a grid of 184 rows by 156 columns, and comprises 14,118 active cells each measuring 1 mile on a side. It simulates time periods from 1918 to 1998 along with further time periods to 2049 testing different pumping scenarios. Model flux boundary conditions were specified for rivers, general head boundaries along parts of the western side of the model and parts of Crowleys Ridge, and a specified head boundary across the aquifer further north in Missouri. Model calibration was conducted for observed water levels for the years 1972, 1982, 1992, and 1998. The average absolute residual was 4.69 feet and the root-mean square error was 6.04 feet for the hydraulic head observations for 1998. Hydraulic-conductivity values obtained during the calibration process were 230 feet per day for the upper layer and ranged from 230 to 730 feet per day for the lower layer with the maximum mean for the combined aquifer of 480 feet per day. Specific yield values were 0.30 throughout the model and specific storage values were 0.000001 inverse-feet throughout

  10. Feeding strategies for groundwater enhanced biodenitrification in an alluvial aquifer: chemical, microbial and isotope assessment of a 1D flow-through experiment.

    PubMed

    Vidal-Gavilan, G; Carrey, R; Solanas, A; Soler, A

    2014-10-01

    Nitrate-removal through enhanced in situ biodenitrification (EISB) is an existing alternative for the recovery of groundwater quality, and is often suggested for use in exploitation wells pumping at small flow-rates. Innovative approaches focus on wider-scale applications, coupling EISB with water-management practices and new monitoring tools. However, before this approach can be used, some water-quality issues such as the accumulation of denitrification intermediates and/or of reduced compounds from other anaerobic processes must be addressed. With such a goal, a flow-through experiment using 100mg-nitrate/L groundwater was built to simulate an EISB for an alluvial aquifer. Heterotrophic denitrification was induced through the periodic addition of a C source (ethanol), with four different C addition strategies being evaluated to improve the quality of the denitrified water. Chemical, microbial and isotope analyses of the water were performed. Biodenitrification was successfully stimulated by the daily addition of ethanol, easily achieving drinking water standards for both nitrate and nitrite, and showing an expected linear trend for nitrogen and oxygen isotope fractionation, with a εN/εO value of 1.1. Nitrate reduction to ammonium was never detected. Water quality in terms of remaining C, microbial counts, and denitrification intermediates was found to vary with the experimental time, and some secondary microbial respiration processes, mainly manganese reduction, were suspected to occur. Carbon isotope composition from the remaining ethanol also changed, from an initial enrichment in (13)C-ethanol compared to the value of the injected ethanol (-30.6‰), to a later depletion, achieving δ(13)C values well below the initial isotope composition (to a minimum of -46.7‰). This depletion in the heavy C isotope follows the trend of an inverse fractionation. Overall, our results indicated that most undesired effects on water quality may be controlled through the

  11. Hydrology of carbonate aquifers in southwestern Linn County and adjacent parts of Benton, Iowa, and Johnson Counties, Iowa

    USGS Publications Warehouse

    Wahl, Kenneth; Bunker, Bill J.

    1986-01-01

    Water analyses from the Devonian and Silurian aquifers indicate that they are of similar chemical quality at most locations in the study area. However, they may commonly contain concentrations of sulfate that exceed 1,000 mil grams per liter. Dissolved-solids concentrations as much as 2,350 milligrams per liter occur in the Silurian aquifer in the western and southwestern part of the study area. Water from the Quaternary aquifer generally is suitable for most uses and dissolved-solids concentrations generally are less than 750 milligrams per liter.

  12. Regional potentiometric-surface map of the Great Basin carbonate and alluvial aquifer system in Snake Valley and surrounding areas, Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

    USGS Publications Warehouse

    Gardner, Philip M.; Masbruch, Melissa D.; Plume, Russell W.; Buto, Susan G.

    2011-01-01

    Water-level measurements from 190 wells were used to develop a potentiometric-surface map of the east-central portion of the regional Great Basin carbonate and alluvial aquifer system in and around Snake Valley, eastern Nevada and western Utah. The map area covers approximately 9,000 square miles in Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada. Recent (2007-2010) drilling by the Utah Geological Survey and U.S. Geological Survey has provided new data for areas where water-level measurements were previously unavailable. New water-level data were used to refine mapping of the pathways of intrabasin and interbasin groundwater flow. At 20 of these locations, nested observation wells provide vertical hydraulic gradient data and information related to the degree of connection between basin-fill aquifers and consolidated-rock aquifers. Multiple-year water-level hydrographs are also presented for 32 wells to illustrate the aquifer system's response to interannual climate variations and well withdrawals.

  13. Geochemistry and isotope hydrology of representative aquifers in the Great Basin region of Nevada, Utah, and adjacent states

    USGS Publications Warehouse

    Thomas, J.M.; Welch, A.H.; Dettinger, M.D.

    1996-01-01

    This report briefly describes the general quality and chemical character of the ground water, discusses in detail the geochemical and hydrologic processes that produce the chemical and isotopic compositions of water in the two principal types of aquifers (basin fill and carbonate rock), delineates flow systems in carbonate-rock aquifers of southern Nevada, and discusses ground-water ages and flow velocities within the carbonate-rock systems.

  14. Groundwater quality in the shallow aquifers of the Tulare, Kaweah, and Tule Groundwater Basins and adjacent highlands areas, Southern San Joaquin Valley, California

    USGS Publications Warehouse

    Fram, Miranda S.

    2017-01-18

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created 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 shallow aquifers of the Tulare, Kaweah, and Tule groundwater basins and adjacent highlands areas of the southern San Joaquin Valley constitute one of the study units being evaluated.

  15. Spatio-temporal approach and modeling for the identification and quantification of water exchange between a river and its alluvial aquifer - application to the Rhône River

    NASA Astrophysics Data System (ADS)

    Lalot, E.; Paran, F.; Graillot, D.; Batton-hubert, M.

    2012-04-01

    In order to better understand the water exchange dynamics between large rivers and their alluvial aquifer three types of tools were used and compared: deterministic models, black box models and models of mutivariate spatial analysis. The complementarity between these methods is discussed on an area with high socio-economic stakes concerning the use of water resources, around Péage-de-Roussillon (France, Rhône River). The studied area has a length of 22 kilometers and a width comprised between 2 and 4 kilometers. The alluvial layer shows a high conductivity (10-2 to 10-4 m/s) and has a depth varying between 10 and 30 meters. A 5.5 years period was considered with time steps of 4 hours between measurements of water level. The groundwater level was monitored in 20 stations while 5 river gauging stations were used. As the collected data show some gaps and errors, a signal analysis was performed to detect the errors and auto regressive linear models were used to rebuild the missing data. Several tests using signal processing techniques were performed to characterise the aquifer behaviour. A principal component analysis was undertaken on the piezometric head data. It allowed defining the two main explanatory factors to the groundwater fluctuations: the variability of surface water level and of pumping rates. Spectral analyses were also carried out through the use of Fourier and Wavelet analysis. Mapping of different areas within the aquifer is based on the frequency filtering, on the delay, on the attenuation and on the correlation between the surface water levels and the piezometric heads. It was found that these parameters are not always correlated to one another. However the effect of river fluctuations on groundwater level decreases overall with the distance to the river. Then a deterministic physically-based model of the aquifer was implemented: a surface water model was linked with a groundwater model. An accurate computation of the surface water level was found

  16. Groundwater environmental tracer data collected from the Chicot, Evangeline, and Jasper aquifers in Montgomery County and adjacent counties, Texas, 2008

    USGS Publications Warehouse

    Oden, Timothy D.

    2011-01-01

    The Gulf Coast aquifer system is the primary water supply for Montgomery County in southeastern Texas, including part of the Houston metropolitan area and the cities of Magnolia, Conroe, and The Woodlands Township, Texas. The U.S. Geological Survey, in cooperation with the Lone Star Groundwater Conservation District, collected environmental tracer data in the Gulf Coast aquifer system, primarily in Montgomery County. Forty existing groundwater wells screened in the Gulf Coast aquifer system were selected for sampling in Montgomery County (38 wells), Waller County (1 well), and Walker County (1 well). Groundwater-quality samples, physicochemical properties, and water-level data were collected once from each of the 40 wells during March-September 2008. Groundwater-quality samples were analyzed for dissolved gases and the environmental tracers sulfur hexafluoride, chlorofluorocarbons, tritium, helium-4, and helium-3/tritium. Water samples were collected and processed onsite using methods designed to minimize changes to the water-sample chemistry or contamination from the atmosphere. Replicate samples for quality assurance and quality control were collected with each environmental sample. Well-construction information and environmental tracer data for March-September 2008 are presented.

  17. Recalibration of a ground-water flow model of the Mississippi River Valley alluvial aquifer in Southeastern Arkansas, 1918, with simulations of hydraulic heads caused by projected ground-water withdrawals through 2049

    USGS Publications Warehouse

    Stanton, Gregory P.; Clark, Brian R.

    2003-01-01

    The Mississippi River Valley alluvial aquifer, encompassing parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee supplies an average of 5 billion gallons of water per day. However, withdrawals from the aquifer in recent years have caused considerable drawdown in the hydraulic heads in southeastern Arkansas and other areas. The effects of current ground-water withdrawals and potential future withdrawals on water availability are major concerns of water managers and users as well as the general public. A full understanding of the behavior of the aquifer under various water-use scenarios is critical for the development of viable water-management and alternative source plans. To address these concerns, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Vicksburg District, and the Arkansas Soil and Water Conservation Commission developed and calibrated a ground-water flow model for the Mississippi River valley alluvial aquifer in southeastern Arkansas to simulate hydraulic heads caused by projected ground-water withdrawals. A previously published ground-water flow model for the alluvial aquifer in southeastern Arkansas was updated and recalibrated to reflect more current pumping stresses with additional stress periods added to bring the model forward from 1982 to 1998. The updated model was developed and calibrated with MODFLOW-2000 finite difference numerical modeling and parameter estimation software. The model was calibrated using hydraulic-head data collected during 1972 and 1982 and hydraulic-head measurements made during spring (February to April) of 1992 and 1998. The residuals for 1992 and 1998 have a mean absolute value of 4.74 and 5.45 feet, respectively, and a root mean square error of 5.9 and 6.72 feet, respectively. The effects of projected ground-water withdrawals were simulated through 2049 in three predictive scenarios by adding five additional stress periods of 10 years each. In the three scenarios

  18. Detection of pharmaceuticals and other personal care products in groundwater beneath and adjacent to onsite wastewater treatment systems in a coastal plain shallow aquifer.

    PubMed

    Del Rosario, Katie L; Mitra, Siddhartha; Humphrey, Charles P; O'Driscoll, Michael A

    2014-07-15

    Onsite wastewater treatment systems (OWTS) are the predominant disposal method for human waste in areas without municipal sewage treatment alternatives. Relatively few studies have addressed the release of pharmaceuticals and personal care products (PPCPs) from OWTS to groundwater. PPCP fate and transport from OWTS are important, particularly where these systems are adjacent to sensitive aquatic ecosystems such as coastal areas or wetlands. The objectives of this study were to identify PPCPs in residential wastewater and groundwater beneath OWTS and to characterize the environmental conditions affecting the OWTS discharge of PPCPs to nearby streams. The study sites are in coastal plain aquifers, which may be considered vulnerable "end-members" for subsurface PPCP transport. The PPCPs most commonly detected in the OWTS, at concentrations ranging from 0.12 μg L(-1) to 12.04 μg L(-1) in the groundwater, included: caffeine, ibuprofen, DEET, and homosalate. Their presence was related to particulate and dissolved organic carbon abundance.

  19. 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).

    NASA Astrophysics Data System (ADS)

    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

  20. Hydrogeology at Air Force Plant 4 and vicinity and water quality of the Paluxy Aquifer, Fort Worth, Texas

    USGS Publications Warehouse

    Kuniansky, Eve L.; Jones, Sonya A.; Brock, Robert D.; Williams, M.D.

    1996-01-01

    Ground water in the surficial terrace alluvial aquifer is contaminated at Air Force Plant 4, Fort Worth, Texas, and at the adjacent Naval Air Station. Some of the contaminated water has leaked from the terrace alluvial aquifer to an uppermost interval of the Paluxy Formation (the Paluxy "upper sand") beneath the east parking lot, east of the assembly building, and to the upper and middle zones of the Paluxy aquifer near Bomber Road, west of the assembly building. Citizens are concerned that contaminants from the plant, principally trichloroethylene and chromium might enter nearby municipal and domestic wells that pump water from the middle and lower zones of the Paluxy aquifer. Geologic formations that crop out in the study area, from oldest to youngest, are the Paluxy Formation (aquifer), Walnut Formation (confining unit), and Goodland Limestone (confining unit). Beneath the Paluxy Formation is the Glen Rose Formation (confining unit) and Twin Mountains Formation (aquifer). The terrace alluvial deposits overlie these Cretaceous rocks. The terrace alluvial aquifer, which is not used for municipal water supply, is separated from the Paluxy aquifer by the Goodland-Walnut confining unit. The confining unit restricts the flow of ground water between these aquifers in most places; however, downward leakage to the Paluxy aquifer might occur through the "window," where the confining unit is thin or absent. The Paluxy aquifer is divided into upper, middle, and lower zones. The Paluxy "upper sand" underlying the "window" is an apparently isolated, mostly unsaturated, sandy lens within the uppermost part of the upper zone. The Paluxy aquifer is recharged by leakage from Lake Worth and by precipitation on the outcrop area. Discharge from the aquifer primarily occurs as pumpage from municipal and domestic wells. The Paluxy aquifer is separated from the underlying Twin Mountains aquifer by the Glen Rose confining unit. Water-level maps indicate that (1) ground water in the

  1. Geoelectric resistivity sounding of riverside alluvial aquifer in an agricultural area at Buyeo, Geum River watershed, Korea: an application to groundwater contamination study

    NASA Astrophysics Data System (ADS)

    Park, Yong-Hee; Doh, Seong-Jae; Yun, Seong-Taek

    2007-12-01

    Twenty profiles of vertical electric soundings (VES) were obtained in a riverside alluvium at the Buyeo area, South Korea, to examine the variations of subsurface geology and associated groundwater chemistry. The combination of the VES data with the borehole data provided useful information on subsurface hydrogeologic conditions. The vestige of an ancient river channel (e.g. oxbow lake) was identified on the resistivity profiles by the lateral continuation of a near-surface perched aquifer parallel to the river. Such a perched aquifer is typically developed in the area with a clay-rich silty surface alluvium which prohibits the infiltration of oxygen. Therefore, groundwater below the oxbow lake shows a very low nitrate concentration and Eh values under the strong anoxic condition. The distribution of water resistivity is correlated with that of measured total dissolved solids concentration in groundwater, while the earth resistivity of the aquifer shows a significant spatial variation. It is interpreted that the earth resistivity of the aquifer is mainly controlled by the soil type rather than by the water chemistry in the study area.

  2. Methods and Applications of Digital-Model Simulation of the Red River Alluvial Aquifer, Shreveport to the Mouth of the Black River, Louisiana.

    DTIC Science & Technology

    1980-05-01

    41 Transmissivity----------------------------------------------------- 42 Change in evapotranspiration with change in potentiometric surface...confined aquifer (node-level nap) -------------- 43 Changes in stream stage-------------------------------------------- 47 Calibration and verification of...channel showing the method for computing stage change --------------------- 48 20. Examples of spring and fall calibration charts from DATE program

  3. 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

    USGS Publications Warehouse

    Ryter, Derek W.; Correll, Jessica S.

    2016-01-14

    A hypothetical severe drought was simulated by using aquifer recharge flow rates during the drought year of 2011 for a period of 10 years. All other flows including evapotranspiration and groundwater pumping were set at estimated 2011 rates. The hypothetical drought caused a decrease in water in aquifer storage by about 7 percent in Reach I and 7 percent in Reach II. Another analysis of the effects of hypothetical drought estimated the effects of drought on streamflow and lake storage. The hypothetical drought was simulated by decreasing recharge by 75 percent for a selected 10-year period (1994–2004) during the 1980–2011 simulation. In Reach I, the amounts of water stored in Canton Lake and streamflow at the Seiling, Okla., streamflow-gaging station were analyzed. Streamflow at the Seiling station decreased by a mean of 75 percent and was still diminished by 10 percent after 2011. In Reach II, the effect of drought on the streamflow at the Yukon, Okla., streamflow-gaging station was examined. The greatest mean streamflow decrease was approximately 60 percent during the simulated drought, and after 2011, the mean decrease in streamflow was still about 5 percent. Canton Lake storage decreased by as much as 83 percent during the simulated drought and did not recover by 2011.

  4. Analyses and estimates of hydraulic conductivity from slug tests in alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    USGS Publications Warehouse

    Houston, Natalie A.; Braun, Christopher L.

    2004-01-01

    This report describes the collection, analyses, and distribution of hydraulic-conductivity data obtained from slug tests completed in the alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas, during October 2002 and August 2003 and summarizes previously available hydraulic-conductivity data. The U.S. Geological Survey, in cooperation with the U.S. Air Force, completed 30 slug tests in October 2002 and August 2003 to obtain estimates of horizontal hydraulic conductivity to use as initial values in a ground-water-flow model for the site. The tests were done by placing a polyvinyl-chloride slug of known volume beneath the water level in selected wells, removing the slug, and measuring the resulting water-level recovery over time. The water levels were measured with a pressure transducer and recorded with a data logger. Hydraulic-conductivity values were estimated from an analytical relation between the instantaneous displacement of water in a well bore and the resulting rate of head change. Although nearly two-thirds of the tested wells recovered 90 percent of their slug-induced head change in less than 2 minutes, 90-percent recovery times ranged from 3 seconds to 35 minutes. The estimates of hydraulic conductivity range from 0.2 to 200 feet per day. Eighty-three percent of the estimates are between 1 and 100 feet per day.

  5. 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)

    NASA Astrophysics Data System (ADS)

    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.

  6. Water Resources of the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

    USGS Publications Warehouse

    Welch, Alan H.; Bright, Daniel J.; Knochenmus, Lari A.

    2008-01-01

    INTRODUCTION This report summarizes results of a water-resources study for White Pine County, Nevada, and adjacent areas in east-central Nevada and western Utah. The Basin and Range carbonate-rock aquifer system (BARCAS) study was initiated in December 2004 through Federal legislation (Section 301(e) of the Lincoln County Conservation, Recreation, and Development Act of 2004; PL108-424) directing the Secretary of the Interior to complete a water-resources study through the U.S. Geological Survey, Desert Research Institute, and State of Utah. The study was designed as a regional water-resource assessment, with particular emphasis on summarizing the hydrogeologic framework and hydrologic processes that influence ground-water resources. The study area includes 13 hydrographic areas that cover most of White Pine County; in this report however, results for the northern and central parts of Little Smoky Valley were combined and presented as one hydrographic area. Hydrographic areas are the basic geographic units used by the State of Nevada and Utah and local agencies for water-resource planning and management, and are commonly defined on the basis of surface-water drainage areas. Hydrographic areas were further divided into subbasins that are separated by areas where bedrock is at or near the land surface. Subbasins are the subdivisions used in this study for estimating recharge, discharge, and water budget. Hydrographic areas are the subdivision used for reporting summed and tabulated subbasin estimates.

  7. Water Resources of the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah - Draft Report

    USGS Publications Warehouse

    Welch, Alan H.; Bright, Daniel J.

    2007-01-01

    Summary of Major Findings This report summarizes results of a water-resources study for White Pine County, Nevada, and adjacent areas in east-central Nevada and western Utah. The Basin and Range carbonate-rock aquifer system (BARCAS) study was initiated in December 2004 through Federal legislation (Section 131 of the Lincoln County Conservation, Recreation, and Development Act of 2004) directing the Secretary of the Interior to complete a water-resources study through the U.S. Geological Survey, Desert Research Institute, and State of Utah. The study was designed as a regional water-resource assessment, with particular emphasis on summarizing the hydrogeologic framework and hydrologic processes that influence ground-water resources. The study area includes 13 hydrographic areas that cover most of White Pine County; in this report however, results for the northern and central parts of Little Smoky Valley were combined and presented as one hydrographic area. Hydrographic areas are the basic geographic units used by the State of Nevada and Utah and local agencies for water-resource planning and management, and are commonly defined on the basis of surface-water drainage areas. Hydrographic areas were further divided into subbasins that are separated by areas where bedrock is at or near the land surface. Subbasins represent subdivisions used in this study for estimating recharge, discharge, and water budget. Hydrographic areas represent the subdivision used for reporting summed and tabulated subbasin estimates.

  8. Contribution of alluvial groundwater to the outflow of mountainous catchments

    NASA Astrophysics Data System (ADS)

    Käser, Daniel; Hunkeler, Daniel

    2016-02-01

    Alluvial aquifers in mountainous regions cover typically a limited area. Their contribution to catchment storage and outflow is rarely isolated; alluvial groundwater discharge under gauging stations is generally assumed negligible; and hydrological models tend to lump alluvial storage with other units. The role of alluvial aquifers remains therefore unclear: can they contribute significantly to outflow when they cover a few percent of catchment area? Should they be considered a dynamic storage unit or merely a transmission zone? We address these issues based on the continuous monitoring of groundwater discharge, river discharge (one year), and aquifer storage (6 months) in the 6 km2 alluvial system of a 194 km2 catchment. River and groundwater outflow were measured jointly through "coupled gauging stations." The contribution of alluvial groundwater to outflow was highest at the outlet of a subcatchment (52 km2), where subsurface discharge amounted to 15% of mean annual outflow, and 85% of outflow during the last week of a drought. In this period, alluvial-aquifer depletion supported 75% of the subcatchment outflow and 35% of catchment outflow—thus 3% of the entire catchment supported a third of the outflow. Storage fluctuations occurred predominantly in the aquifer's upstream part, where heads varied over 6 m. Not only does this section act as a significant water source, but storage recovers also rapidly at the onset of precipitation. Storage dynamics were best conceptualized along the valley axis, rather than across the more conventional riparian-channel transect. Overall the contribution of alluvial aquifers to catchment outflow deserves more attention.

  9. Isotopes in the Hueco Bolson aquifer, Texas (USA) and Chihuahua (Mexico): local and general implications for recharge sources in alluvial basins

    NASA Astrophysics Data System (ADS)

    Eastoe, Christopher J.; Hibbs, Barry J.; Olivas, Alfredo Granados; Hogan, James F.; Hawley, John; Hutchison, William R.

    2008-06-01

    Stable isotope data for the Hueco Bolson aquifer (Texas, USA and Chihuahua, Mexico) distinguish four water types. Two types relate to recharge from the Rio Grande: pre-dam (pre-1916) river water with oxygen-18 and deuterium (δ18O, δD, ‰) from (-11.9, -90) to (-10.1, -82), contrasts with present-day river water (-8.5, -74) to (-5.3, -56). Pre-dam water is found beneath the Rio Grande floodplain and Ciudad Juárez, and is mixed with post-dam river water beneath the floodplain. Two other types relate to recharge of local precipitation; evidence of temporal change of precipitation isotopes is present in both types. Recharge from the Franklin and Organ Mountains plots between (-10.9, -76) and (-8.5, -60) on the global meteoric water line (GMWL), and is found along the western side of the Hueco Bolson, north of the Rio Grande. Recharge from the Diablo Plateau plots on an evaporation trend originating on the GMWL near (-8.5, -58). This water is found in the southeastern Hueco Bolson, north of the river; evaporation may be related to slow recharge through fine-grained sediment. Pre-dam water, recognizable by isotope composition, provides information on groundwater residence times in this and other dammed river basins.

  10. GIS-based colour composites and overlays to delineate heavy metal contamination zones in the shallow alluvial aquifers, Ankaleshwar industrial estate, south Gujarat, India

    NASA Astrophysics Data System (ADS)

    Kumar, Suyash; Shirke, K. D.; Pawar, N. J.

    2008-03-01

    In an attempt to delineate heavy metal contamination precincts and to evaluate the extent and degree of toxic levels, besides their possible sources, 38 water samples from Ankaleshwar Industrial Estate, south Gujarat, India were analyzed. By clutching geochemical analyses and GIS-based colour composites areas depicting anomalously high concentration of heavy metals (Mo, Zn, Pb, Ni, Co, Cd, etc.) in the groundwater were revealed. The multicomponent overlays in grey-scale facilitated in identifying situates of heavy metal ‘hot spots’, and lateral protuberances of the contamination plume around defile stretch of the main stream Amla Khadi flowing through the area. The multiple pollution plumes emerging from other parts of the area further coincide with effluent laden streams and small channels indicating industrial establishments as major sources of groundwater contamination. Influent nature of the streams, accelerated infiltration process, high mass influx and shallow groundwater table are the factors conducive for easy access of heavy metals to the phreatic aquifers affecting over 20 km2 area. On the basis of P/ U ratios (concentration of metals in polluted water to unpolluted water), geogenic and anthropogenic sources have been identified. Very high levels of technogenic elements present in the ground water raise concerns about possible migration into food crops, as the area is an important horticultural locale and is highly cultivated.

  11. Different hydraulic responses to the 2008 Wenchuan and 2011 Tohoku earthquakes in two adjacent far-field wells: the effect of shales on aquifer lithology

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Fu, Li-Yun; Ma, Yuchuan; Hu, Junhua

    2016-11-01

    Zuojiazhuang and Baodi are two adjacent wells ( 50 km apart) in northern China. The large 2008 M w 7.9 Wenchuan and 2011 M w 9.1 Tohoku earthquakes induced different co-seismic water-level responses in these far-field (>1000 km) wells. The co-seismic water-level changes in the Zuojiazhuang well exhibited large amplitudes ( 2 m), whereas those in the Baodi well were small and unclear ( 0.05 m). The mechanism of the different co-seismic hydraulic responses in the two wells needs to be revealed. In this study, we used the barometric responses in different frequency domains and the phase shifts and amplitude ratios of the tidal responses (M2 wave), together with the well logs, to explain this inconformity. Our calculations show that the co-seismic phase shifts of the M2 wave decreased or remained unchanged in the Baodi well, which was quite different from the Zuojiazhuang well and from the commonly accepted phenomena. According to the well logs, the lithology of the Baodi well is characterized by the presence of a significant amount of shale. The low porosity/permeability of shale in the Baodi well could be the cause for the unchanged and decreased phase shifts and tiny co-seismic water-level responses. In addition, shale is one of the causes of positive phase shifts and indicates a vertical water-level flow, which may be due to a semi-confined aquifer or the complex and anisotropic fracturing of shale.

  12. Statistical analysis of aquifer-test results for nine regional aquifers in Louisiana

    USGS Publications Warehouse

    Martin, Angel; Early, D.A.

    1987-01-01

    This report, prepared as part of the Gulf Coast Regional Aquifer-System Analysis project, presents a compilation, summarization, and statistical analysis of aquifer-test results for nine regional aquifers in Louisiana. These are from youngest to oldest: The alluvial, Pleistocene, Evangeline, Jasper, Catahoula, Cockfield, Sparta, Carrizo, and Wilcox aquifers. Approximately 1,500 aquifer tests in U.S. Geological Survey files in Louisiana were examined and 1,001 were input to a computer file. Analysis of the aquifer test results and plots that describe aquifer hydraulic characteristics were made for each regional aquifer. Results indicate that, on the average, permeability (hydraulic conductivity) generally tends to decrease from the youngest aquifers to the oldest. The most permeable aquifers in Louisiana are the alluvial and Pleistocene aquifers; whereas, the least permeable are the Carrizo and Wilcox aquifers. (Author 's abstract)

  13. Activity ratios of (234)U/(238)U and (226)Ra/(228)Ra for transport mechanisms of elevated uranium in alluvial aquifers of groundwater in south-western (SW) Punjab, India.

    PubMed

    Kumar, A; Karpe, R K; Rout, S; Gautam, Y P; Mishra, M K; Ravi, P M; Tripathi, R M

    2016-01-01

    The concentrations of total dissolved uranium (U), its isotopic composition ((234)U, (235)U, (238)U) and two long lived Ra isotopes ((226)Ra and (228)Ra) in alluvial aquifers of groundwater were determined to investigate the groundwater flow pattern in the south-western (SW) Punjab, India. Particular attention was given to the spatial variability of activity ratios (ARs) of (234)U/(238)U and (226)Ra/(228)Ra to predict the possible sources and supply process of U into the water from the solid phase. The measured groundwater (234)U/(238)U ARs were ∼1 or >1 in the shallow zone (depth < 30 m) with high U concentration and <1 in the deeper zone (depth > 30 m) with relatively low U concentration. The simultaneous elevated U concentration and (234)U/(238)U ARs in waters were possibly due to differences in imprints of rock-water interactions under hydrologic conditions. However, (234)U/(238)U ARs < 1 clearly indicate the lack of recharge from surface water to groundwater leading to (234)U deficit in groundwater. This deficit might be also attributed to alpha recoil processes under strong dissolution. Overall, the decreasing pattern of (234)U/(238)U ARs observed from SE to SW or NW ward clearly indicates a groundwater flow paths from SE to SW/NW. Similarly, (226)Ra/(238)U ARs < 1 for all water samples reflect that the precursor (238)U is fairly mobile relative to (226)Ra. This might be due to unusually high amount of (238)U in groundwaters and subsequently the different geochemistry of the two isotopes. On the other hand, (226)Ra/(228)Ra ARs in groundwaters varied widely and observed about 50-300 times higher than (238)U/(232)Th ARs in granitic rocks or soils. Such elevation in ARs might be attributed to different dissolution properties of their parents during water-rock interactions or lattice damage during decay or local enrichments of uranium in the aquifers.

  14. A description of the hydrologic system and the effects of coal mining on water quality in the East Fork Little Chariton River and the alluvial aquifer between Macon and Huntsville, north-central Missouri

    USGS Publications Warehouse

    Hall, D.C.

    1986-01-01

    The quality of surface and groundwater has been affected by abandoned strip mines and by abandoned underground mines in a 110-sq mi subbasin of the East Fork Little Chariton River. More than 14% of the area was strip mined for coal before 1979. The hydrologic system in the area was investigated and the effects of coal mining on quality of water in the river and alluvial aquifer were analyzed, with major emphasis on defining strip-mining effects. The groundwater gradient was from glacial drift or coal spring to alluvium to the East Fork Little Chariton River, and was greatest in spring and least in fall. Seepage from alluvium to the East Fork Little Chariton River occurs throughout the year, except during drought conditions when the only river flow is water released from Long Branch Lake. In the East Fork Little Chariton River median dissolved-solids concentrations increased from 153 mg/L near Macon to 630 mg/L near Huntsville and median sulfate concentrations increased from 36 mg/L near Macon to 360 mg/L near Huntsville. The median dissolved-solids concentration in water from the alluvium increased from 408 mg/L upstream from the strip mines to 641 mg/L near the mines and median dissolved-sulfate concentration increased from 140 to 350 mg/L. The sulfate-to-chloride ratio, used as the most sensitive indicator of strip-mining effects, increased markedly downstream in the East Fork Little Chariton River and nearby Middle Fork Little Chariton River, which also is affected by strip mining. There were no significant increases in sulfate-to-chloride ratio and dissolved-solids concentrations in comparable nearby subbasins of the Grand, Thompson, and Chariton Rivers where there was no mining. (Author 's abstract)

  15. Uranium and Strontium Isotopic Study of the Hydrology of the Alluvial Aquifer at the Rifle Former U Mine Tailings Site, Colorado

    NASA Astrophysics Data System (ADS)

    Christensen, J. N.; Shiel, A. E.; Conrad, M. E.; Williams, K. H.; Dong, W.; Tokunaga, T. K.; Wan, J.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    the site near its eastern edge has significant hydraulic connectivity with the aquifer affecting nearby wells and constraining the boundary conditions for the Rifle hydrologic model. Vadose zone porewater has d235U ranging from 0.03 to 0.6‰ reflecting local smear-zone redox processes or the history of ore sources processed at the Rifle Mill.

  16. Identification of groundwater contamination sources of nitrate and sulfate in shallow alluvial aquifers using a dual-isotope approach in an agricultural area

    NASA Astrophysics Data System (ADS)

    Kaown, D.; Koh, D.; Mayer, B.; Hyun, Y.; Bae, G.; Lee, K.

    2007-12-01

    The elevated level of nitrate in groundwater is a serious problem in Korean agricultural areas. Yupori, a small agricultural area in Chuncheon (Korea), shows a rising level of NO3-N and displays multiple NO3-N sources from non-point and point sources in shallow aquifer groundwater. Numerous vegetable fields are located in the western part of the study area and fruit orchards dominate the landscape with only few vegetable fields in the eastern part of the study area. The source identification of groundwater contamination from overburden agricultural area was undertaken by analyzing hydrochemical data and stable isotopic compositions of dissolved nitrate and sulfate (¥ä15N-NO3-, ¥ä18O-NO3-, ¥ä34S-SO42-, and ¥ä18O-SO42-). The measurements of ¥ä15N- NO3- are in the range of 7.1 to 14.4¢¶ and the values of ¥ä18O-NO3- are in the range of -1.8 to 6.5¢¶. High ¥ä15N-NO3- values shown at low concentrations of nitrate in the eastern Yupori are characteristics of manure- derived nitrate and organic soil. The values of ¥ä34S-SO4-2 ranged from 2.9 to 9.9¢¶ and ¥ä18O-SO42- ranged from 2.5 to 4.7¢¶. At high concentrations of SO42- in the western Yupori, the value of ¥ä34S-SO42- are low around 3-4¢¶. The value of ¥ä34S-SO42- increased with decreasing SO42- concentration in the eastern Yupori. Groundwater quality and stable isotopic compositions of dissolved nitrate and sulfate seem to be significantly affected by agricultural land use pattern of the study site.

  17. A Numerical Study for Groundwater Flow, Heat and Solute Transport Associated with Operation of Open-loop Geothermal System in Alluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Park, D. K.; Bae, G. O.; Lee, K. K.

    2014-12-01

    The open-loop geothermal system directly uses a relatively stable temperature of groundwater for cooling and heating in buildings and thus has been known as an eco-friendly, energy-saving, and cost-efficient technique. The facility for this system was installed at a site located near Paldang-dam in Han-river, Korea. Because of the well-developed alluvium, the site might be appropriate to application of this system requiring extraction and injection of a large amount of groundwater. A simple numerical experiment assuming various hydrogeologic conditions demonstrated that regional groundwater flow direction was the most important factor for efficient operation of facility in this site having a highly permeable layer. However, a comparison of river stage data and groundwater level measurements showed that the daily and seasonal controls of water level at Paldang-dam have had a critical influence on the regional groundwater flow in the site. Moreover, nitrate concentrations measured in the monitoring wells gave indication of the effect of agricultural activities around the facility on the groundwater quality. The facility operation, such as extraction and injection of groundwater, will obviously affect transport of the agricultural contaminant and, maybe, it will even cause serious problems in the normal operation. Particularly, the high-permeable layer in this aquifer must be a preferential path for quick spreadings of thermal and contaminant plumes. The objective of this study was to find an efficient, safe and stable operation plan of the open-loop geothermal system installed in this site having the complicated conditions of highly permeable layer, variable regional groundwater flow, and agricultural contamination. Numerical simulations for groundwater flow, heat and solute transport were carried out to analyze all the changes in groundwater level and flow, temperature, and quality according to the operation, respectively. Results showed that an operation plan for

  18. Distribution of carbonate-rock aquifers and the potential for their development, southern Nevada and adjacent parts of California, Arizona, and Utah

    USGS Publications Warehouse

    Dettinger, M.D.; Harrill, J.R.; Schmidt, D.L.; Hess, J.W.

    1995-01-01

    In 1985, the State of Nevada entered into a cooperative effort with the U.S. Department of the Interior to study and test the State's carbonate- rock aquifers. The studies were focused on southern Nevada and were intended to address the following concerns: Where is water potentially available in the aquifers?; How much water potentially can bewithdrawn from aquifers?; and What effects might result from development of the aquifers? The studies included basic-data collection, geologic mapping, geophysical and geochemical analyses, well drilling, and aquifer testing. The studies showed that the carbonate rocks are continuous and extensive enough to form regional aquifer systems only beneath thecentral third of the region. About 130,000 acre-feet per year of ground water flows through all the aquifers in this corridor (carbonate and noncarbonate), and about 77,000 acre-feet per year discharges directly from the carbonate-rock aquifers at regional springs in southern Nevada or at discharge areas in Death Valley, California. A larger volume of water -as much as 6 million acre-feet in the upper 100 feet alone-is stored in the rocks. Once depleted, however, that resource would be replenished by natural processes only very slowly. Ultimately, long-term development of the carbonate-rock aquifers would result in depletion of stored water, or in the capture of water that otherwise would discharge from the aquifers of southern Nevada and vicinity, or both. In manyplaces, development might extract water from both carbonate-rock and basin-fill aquifers. Possible effects of developing the carbonate-rock aquifers include declining water levels, decreasing springflow rates, drying up of some streams, playas, and meadows, and changing water quality. Specific impacts would depend upon the magnitude and length of development and site-specific conditions around the areas where the water is withdrawn. Confidence in predictions of the potential effects ofdevelopment of the carbonate

  19. An overview of the transboundary aquifers in East Africa

    NASA Astrophysics Data System (ADS)

    Abiye, Tamiru Alemayehu

    2010-11-01

    A transboundary aquifer is a body of groundwater intersected by two or more countries with the potential threat of dispute over a shared groundwater resource. A large portion of the population in East Africa relies on surface water resources for day-to-day activities; in turn, this is dependent on episodic rainfall. Surface water in the region is vulnerable to pollution and potential climate change. Consequently, frequent conflict over the water use is a regular event in the region. This paper examines the transboundary aquifers and their significance for water supply in the six adjacent Intergovernmental Authority on Development (IGAD) countries (Ethiopia, Eritrea, Sudan, Kenya, Somalia and Djibouti). Analysis of available literature and short field visits to accessible areas were undertaken in order to examine the geology, hydrogeological dynamics, and water use. The geology of the transboundary aquifers is mainly represented by Precambrian basement, Mesozoic sedimentary rocks, Cenozoic volcanics and recent alluvial deposits. Taking into consideration the topographic setting and water circulation, the Ethiopian highlands are the major sources of recharge to the transboundary aquifers of the adjacent countries. The surface runoff drains through 11 major rivers into the neighbouring countries. The groundwater contained in the transboundary aquifers is yet to receive attention by the various countries, but the future trend is towards exploiting the resources to alleviate water shortages in the region. It is hoped that the systematic development of these groundwater resources would strengthen cooperation in this conflict-dominated region.

  20. Atrazine and its metabolites as indicators of stream-aquifer interaction in Kansas, USA

    USGS Publications Warehouse

    Townsend, M.A.; Young, D.P.

    2000-01-01

    A survey of atrazine and its metabolites in Kansas ground water indicated that ground-water quality was impacted by stream-aquifer interaction between rivers in the Kansas River basin and their adjacent alluvial aquifers. Atrazine was detected in 19 of the 78 samples. The most common metabolite, deethylatrazine, was detected in 25 samples, 18 of which also had atrazine. The deethylatrazine/atrazine ratio (DAR) of < 1.0 indicates rapid movement of agricultural chemicals to ground water. In this study, 12 of 18 samples had DAR values < 1.0, suggesting rapid recharge to the aquifers. Hydroxyatrazine is seldom detected in ground water. In this study hydroxyatrazine was detected primarily in wells sited in alluvium of rivers. These rivers contain atrazine in varying concentrations. Results of the study suggest that stream-aquifer interaction is a process contributing to the presence of both atrazine and its metabolites in ground water in these areas.A survey of atrazine and its metabolites in Kansas ground water indicated that ground water quality was impacted by stream-aquifer interaction between rivers in the Kansas River basin and their adjacent alluvial aquifers. Atrazine was detected in 19 of the 78 samples. The most common metabolite, deethylatrazine, was detected in 25 samples, 18 of which also had atrazine. The deethylatrazine/attrazine ratio (DAR) of < 1.0 indicates rapid movement of agricultural chemicals to ground water. In this study, 12 of 18 samples had DAR values < 1.0, suggesting rapid recharge to the aquifers. Hydroxyatrazine is seldom detected in ground water. In this study hydroxyatrazine was detected primarily in wells sited in alluvium of rivers. These rivers contain atrazine in varying concentration. Results of the study suggest that stream-aquifer interaction is a process contributing to the presence of both attrazine and its metabolites in ground water in these areas.

  1. Assessments of aquifer sensitivity on Navajo Nation and adjacent lands and ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project, Arizona, New Mexico, and Utah

    USGS Publications Warehouse

    Blanchard, Paul J.

    2002-01-01

    The U.S. Environmental Protection Agency requested that the Navajo Nation conduct an assessment of aquifer sensitivity on Navajo Nation lands and an assessment of ground-water vulnerability to pesticide contamination on the Navajo Indian Irrigation Project. Navajo Nation lands include about 17,000 square miles in northeastern Arizona, northwestern New Mexico, and southeastern Utah. The Navajo Indian Irrigation Project in northwestern New Mexico is the largest area of agriculture on the Navajo Nation. The Navajo Indian Irrigation Project began operation in 1976; presently (2001) about 62,000 acres are available for irrigated agriculture. Numerous pesticides have been used on the Navajo Indian Irrigation Project during its operation. Aquifer sensitivity is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest. Aquifer sensitivity is a function of the intrinsic characteristics of the geologic material in question, any underlying saturated materials, and the overlying unsaturated zone. Sensitivity is not dependent on agronomic practices or pesticide characteristics.' Ground-water vulnerability is defined by the U.S. Environmental Protection Agency as 'The relative ease with which a contaminant [pesticide] applied on or near a land surface can migrate to the aquifer of interest under a given set of agronomic management practices, pesticide characteristics, and aquifer sensitivity conditions.' The results of the aquifer sensitivity assessment on Navajo Nation and adjacent lands indicated relative sensitivity within the boundaries of the study area. About 22 percent of the study area was not an area of recharge to bedrock aquifers or an area of unconsolidated deposits and was thus assessed to have an insignificant potential for contamination. About 72 percent of the Navajo Nation study area was assessed to be in the categories of most potential

  2. Validation of a Ground-Water Flow Model of the Mississippi River Valley Alluvial Aquifer Using Water-Level and Water-Use Data for 1998-2005 and Evaluation of Water-Use Scenarios

    USGS Publications Warehouse

    Gillip, Jonathan A.; Czarnecki, John B.

    2009-01-01

    A ground-water flow model of the Mississippi River Valley alluvial aquifer in eastern Arkansas, developed in 2003 to simulate the period of 1918-98, was validated with the addition of water-level and water-use data that extended the observation period to 2005. The original model (2003) was calibrated using water-level observations from 1972, 1982, 1992, and 1998, and water-use data through 1997. The original model subsequently was used to simulate water levels from 1999 to 2049 and showed that simulation of continued pumping at the 1997 water-use rate could not be sustained indefinitely without causing dry cells in the model. After publication of the original ground-water flow model, a total of 3,616 water-level observations from 698 locations measured during the period of 1998 to 2005 became available. Additionally, water-use data were compiled and used for the same period, totaling 290,005 discrete water-use values from 43,440 wells with as many as 39,169 wells pumping in any one year. Total pumping (which is primarily agricultural) for this 8-year period was about 2.3 trillion cubic feet of water and was distributed over approximately 10,340 square miles within the model area. An updated version of the original ground-water flow model was used to simulate the period of 1998-2005 with the additional water-level and water-use data. Water-level observations for 1998-2005 ranged from 74 to 293 feet above National Geodetic Vertical Datum of 1929 across the model area. The maximum water-level residual (observed minus simulated water-level values) for the 3,616 water-level observations was 52 feet, the minimum water-level residual was 60 feet, the average annual root mean squared error was 8.2 feet, and the annual average absolute residual was 6.0 feet. A correlation coefficient value of 0.96 was calculated for the line of best fit for observed to simulated water levels for the combined 1998-2005 dataset, indicating a good fit to the data and an acceptable validation

  3. Estimated rates of groundwater recharge to the Chicot, Evangeline and Jasper aquifers by using environmental tracers in Montgomery and adjacent counties, Texas, 2008 and 2011

    USGS Publications Warehouse

    Oden, Timothy D.; Truini, Margot

    2013-01-01

    Recharge rates estimated from environmental tracer data are dependent upon several hydrogeologic variables and have inherent uncertainties. By using the recharge estimates derived from samples collected from 14 wells completed in the Chicot aquifer for which apparent groundwater ages could be determined, recharge to the Chicot aquifer ranged from 0.2 to 7.2 inches (in.) per year (yr). Based on data from one well, estimated recharge to the unconfined zone of the Evangeline aquifer (outcrop) was 0.1 in./yr. Based on data collected from eight wells, estimated rates of recharge to the confined zone of the Evangeline aquifer ranged from less than 0.1 to 2.8 in./yr. Based on data from one well, estimated recharge to the unconfined zone of the Jasper aquifer (outcrop) was 0.5 in./yr. Based on data collected from nine wells, estimated rates of recharge to the confined zone of the Jasper aquifer ranged from less than 0.1 to 0.1 in./yr. The complexity of the hydrogeology in the area, uncertainty in the conceptual model, and numerical assumptions required in the determination of the recharge rates all pose limitations and need to be considered when evaluating these data on a countywide or regional scale. The estimated recharge rates calculated for this study are specific to each well location and should not be extrapolated or inferred as a countywide average. Local variations in the hydrogeology and surficial conditions can affect the recharge rate at a local scale.

  4. Mapping the hydraulic connection between a coalbed and adjacent aquifer: example of the coal-seam gas resource area, north Galilee Basin, Australia

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenjiao; Mariethoz, Gregoire; Schrank, Christoph; Cox, Malcolm; Timms, Wendy

    2016-12-01

    Coal-seam gas production requires groundwater extraction from coal-bearing formations to reduce the hydraulic pressure and improve gas recovery. In layered sedimentary basins, the coalbeds are often separated from freshwater aquifers by low-permeability aquitards. However, hydraulic connection between the coalbed and aquifers is possible due to the heterogeneity in the aquitard such as the existence of conductive faults or sandy channel deposits. For coal-seam gas extraction operations, it is desirable to identify areas in a basin where the probability of hydraulic connection between the coalbed and aquifers is low in order to avoid unnecessary loss of groundwater from aquifers and gas production problems. A connection indicator, the groundwater age indictor (GAI), is proposed, to quantify the degree of hydraulic connection. The spatial distribution of GAI can indicate the optimum positions for gas/water extraction in the coalbed. Depressurizing the coalbed at locations with a low GAI would result in little or no interaction with the aquifer when compared to the other positions. The concept of GAI is validated on synthetic cases and is then applied to the north Galilee Basin, Australia, to assess the degree of hydraulic connection between the Aramac Coal Measure and the water-bearing formations in the Great Artesian Basin, which are separated by an aquitard, the Betts Creek Beds. It is found that the GAI is higher in the western part of the basin, indicating a higher risk to depressurization of the coalbed in this region due to the strong hydraulic connection between the coalbed and the overlying aquifer.

  5. Hydrogeology of the Ramapo River-Woodbury Creek valley-fill aquifer system and adjacent areas in eastern Orange County, New York

    USGS Publications Warehouse

    Heisig, Paul M.

    2015-01-01

    Valley-fill aquifers are modest resources within the area, as indicated by the common practice of completing supply wells in the underlying bedrock rather than the overlying glacial deposits. Groundwater turbidity problems curtail use of the resource. However, additional groundwater resources have been identified by test drilling, and there are remaining untested areas. New groundwater supplies that stress localized aquifer areas will alter the groundwater flow system. Considerations include potential water-quality degradation from nearby land use(s) and, where withdrawals induce infiltration of surface-water, balancing withdrawals with flow requirements for downstream users or for maintenance of stream ecological health.

  6. Assessment of the denitrification process in alluvial wetlands at floodplain scale using the SWAT model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As alluvial plains support intensive agricultural activities, they often suffer from groundwater nitrate pollution. Denitrification is recognized as an important process in nitrate pollution control in riparian zones. In shallow aquifer zones influenced by recharged surface water, denitrification ...

  7. Ground-water flow simulation and chemical and isotopic mixing equation analysis to determine source contributions to the Missouri River alluvial aquifer in the vicinity of the Independence, Missouri, well field

    USGS Publications Warehouse

    Kelly, Brian P.

    2002-01-01

    The city of Independence, Missouri, operates a well field in the Missouri River alluvial aquifer. Steady-state ground-water flow simulation, particle tracking, and the use of chemical and isotopic composition of river water, ground water, and well-field pumpage in a two-component mixing equation were used to determine the source contributions of induced inflow from the Missouri River and recharge to ground water from precipitation in well-field pumpage. Steady-state flow-budget analysis for the simulation-defined zone of contribution to the Independence well field indicates that 86.7 percent of well-field pumpage is from induced inflow from the river, and 6.7 percent is from ground-water recharge from precipitation. The 6.6 percent of flow from outside the simulation-defined zone of contribution is a measure of the uncertainty of the estimation, and occurs because model cells are too large to uniquely define the actual zone of contribution. Flow-budget calculations indicate that the largest source of water to most wells is the Missouri River. Particle-tracking techniques indicate that the Missouri River supplies 82.3 percent of the water to the Independence well field, ground-water recharge from precipitation supplies 9.7 percent, and flow from outside defined zones of contribution supplies 8.0 percent. Particle tracking was used to determine the relative amounts of source water to total well-field pumpage as a function of traveltime from the source. Well-field pumpage that traveled 1 year or less from the source was 8.8 percent, with 0.6 percent from the Missouri River, none from precipitation, and 8.2 percent between starting cells. Well-field pumpage that traveled 2 years or less from the source was 10.3 percent, with 1.8 percent from the Missouri River, 0.2 percent from precipitation, and 8.3 percent between starting cells. Well-field pumpage that traveled 5 years or less from the source was 36.5 percent, with 27.1 percent from the Missouri River, 1.1 percent

  8. Simulated effects of impoundment of lake seminole on ground-water flow in the upper Floridan Aquifer in southwestern Georgia and adjacent parts of Alabama and Florida

    USGS Publications Warehouse

    Jones, L. Elliott; Torak, Lynn J.

    2004-01-01

    Hydrologic implications of the impoundment of Lake Seminole in southwest Georgia and its effect on components of the surface- and ground-water flow systems of the lower Apalachicola?Chattahoochee?Flint (ACF) River Basin were investigated using a ground-water model. Comparison of simulation results of postimpoundment drought conditions (October 1986) with results of hypothetical preimpoundment conditions (a similar drought prior to 1955) provides a qualitative measure of the changes in hydraulic head and ground-water flow to and from streams and Lake Seminole, and across State lines caused by the impoundment. Based on the simulation results, the impoundment of Lake Seminole changed ground-water flow directions within about 20?30 miles of the lake, reducing the amount of ground water flowing from Florida to Georgia southeast of the lake. Ground-water storage was increased by the impoundment, as indicated by a simulated increase of as much as 26 feet in the water level in the Upper Floridan aquifer. The impoundment of Lake Seminole caused changes to simulated components of the ground-water budget, including reduced discharge from the Upper Floridan aquifer to streams (315 million gallons per day); reduced recharge from or increased discharge to regional ground-water flow at external model boundaries (totaling 183 million gallons per day); and reduced recharge from or increased discharge to the undifferentiated overburden (totaling 129 million gallons per day).

  9. Simulation of ground-water flow and the movement of saline water in the Hueco Bolson aquifer, El Paso, Texas, and adjacent areas

    USGS Publications Warehouse

    Groschen, George E.

    1994-01-01

    Results of the projected withdrawal simulations from 1984-2000 indicate that the general historical trend of saline-water movement probably will continue. The saline water in the Rio Grande alluvium is the major source of saline-water intrusion into the freshwater zone throughout the historical period and into the future on the basis of simulation results. Some saline water probably will continue to move downward from the Rio Grande alluvium to the freshwater below. Injection of treated sewage effluent into some wells will create a small zone of freshwater containing slightly increased amounts of dissolved solids in the northern area of the Texas part of the Hueco bolson aquifer. Many factors, such as well interference, pumping schedules, and other factors not specifically represented in the regional simulation, can substantially affect dissolved-solids concentrations at individual wells.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Mapping Evapotranspiration Units in the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

    USGS Publications Warehouse

    Smith, J. LaRue; Laczniak, Randell J.; Moreo, Michael T.; Welborn, Toby L.

    2007-01-01

    Accurate estimates of ground-water discharge are crucial in the development of a water budget for the Basin and Range carbonate-rock aquifer system study area. One common method used throughout the southwestern United States is to estimate ground-water discharge from evapotranspiration (ET). ET is a process by which water from the Earth's surface is transferred to the atmosphere. The volume of water lost to the atmosphere by ET can be computed as the product of the ET rate and the acreage of vegetation, open water, and moist soil through which ET occurs. The procedure used in the study groups areas of similar vegetation, water, and soil conditions into different ET units, assigns an average annual ET rate to each unit, and computes annual ET from each ET unit within the outer extent of potential areas of ground-water discharge. Data sets and the procedures used to delineate the ET-unit map used to estimate ground-water discharge from the study area and a qualitative assessment of the accuracy of the map are described in this report.

  12. Irrigated Acreage Within the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

    USGS Publications Warehouse

    Welborn, Toby L.; Moreo, Michael T.

    2007-01-01

    Accurate delineations of irrigated acreage are needed for the development of water-use estimates and in determining water-budget calculations for the Basin and Range carbonate-rock aquifer system (BARCAS) study. Irrigated acreage is estimated routinely for only a few basins in the study area. Satellite imagery from the Landsat Thematic Mapper and Enhanced Thematic Mapper platforms were used to delineate irrigated acreage on a field-by-field basis for the entire study area. Six hundred and forty-three fields were delineated. The water source, irrigation system, crop type, and field activity for 2005 were identified and verified through field reconnaissance. These data were integrated in a geodatabase and analyzed to develop estimates of irrigated acreage for the 2000, 2002, and 2005 growing seasons by hydrographic area and subbasin. Estimated average annual potential evapotranspiration and average annual precipitation also were estimated for each field.The geodatabase was analyzed to determine the spatial distribution of field locations, the total amount of irrigated acreage by potential irrigation water source, by irrigation system, and by crop type. Irrigated acreage in 2005 totaled nearly 32,000 acres ranging from less than 200 acres in Butte, Cave, Jakes, Long, and Tippett Valleys to 9,300 acres in Snake Valley. Irrigated acreage increased about 20 percent between 2000 and 2005 and increased the most in Snake and White River Valleys. Ground-water supplies as much as 80 percent of irrigation water during dry years. Almost 90 percent of the irrigated acreage was planted with alfalfa.

  13. Application of the top specified boundary layer (TSBL) approximation to initial characterization of an inland aquifer mineralization: 2. Seepage of saltwater through semi-confining layers

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    1998-01-01

    This paper presents a generalized basic study that addresses practical needs for an understanding of the major mechanisms involved in the mineralization of groundwater in the Great Bend Prairie aquifer in south- central Kansas. This Quaternary alluvial aquifer and associated surface waters are subject to contamination by saltwater, which in some areas seeps from the deeper Permian bedrock formation into the overlying freshwater aquifer through semiconfining layers. A simplified conceptual model is adopted. It incorporates the freshwater aquifer whose bottom is comprised of a semiconfining layer through which a hydrologically minor but geochemically important saline water discharge seeps into the aquifer. A hierarchy of approximate approaches is considered to analyze the mineralization processes taking place in the aquifer. The recently developed top specified boundary layer (TSBL) approach is very convenient to use for the initial characterization of these processes, and is further adapted to characterization of head-driven seepage through semi-confining layers. TSBL calculations indicate that the seeping saline water may create two distinct new zones in the aquifer: (1) a completely saline zone (CSZ) adjacent to the semiconfining bottom of the aquifer, and (2) a transition zone (TZ) which develops between the CSZ and the freshwater zone. Some possible scenarios associated with the various mineralization patterns are analyzed and discussed.

  14. Hydrogeologic framework and characterization of the Truxton Aquifer on the Hualapai Reservation, Mohave County, Arizona

    USGS Publications Warehouse

    Bills, Donald J.; Macy, Jamie P.

    2016-12-30

    results and the depth to water in wells. The saturated thickness might be much thicker in parts of the Truxton aquifer where paleochannels are incised into the bedrock underlying the basin fill sediments. The estimated groundwater storage of the Truxton aquifer on the Hualapai Reservation ranges from 620,000 to 940,000 acre-ft and does not include groundwater storage in the aquifer outside the Hualapai Reservation boundary. The results compare well with studies done on alluvial basin aquifers in areas adjacent to this study. The part of the Truxton aquifer on the Hualapai Reservation represents about 20 percent of the entire aquifer. Changing aquifer conditions off reservation are expected to be similar to changes on the reservation and to affect aquifer conditions both on and off the reservation.

  15. Aquifer response to stream-stage and recharge variations. II. Convolution method and applications

    USGS Publications Warehouse

    Barlow, P.M.; DeSimone, L.A.; Moench, A.F.

    2000-01-01

    In this second of two papers, analytical step-response functions, developed in the companion paper for several cases of transient hydraulic interaction between a fully penetrating stream and a confined, leaky, or water-table aquifer, are used in the convolution integral to calculate aquifer heads, streambank seepage rates, and bank storage that occur in response to streamstage fluctuations and basinwide recharge or evapotranspiration. Two computer programs developed on the basis of these step-response functions and the convolution integral are applied to the analysis of hydraulic interaction of two alluvial stream-aquifer systems in the northeastern and central United States. These applications demonstrate the utility of the analytical functions and computer programs for estimating aquifer and streambank hydraulic properties, recharge rates, streambank seepage rates, and bank storage. Analysis of the water-table aquifer adjacent to the Blackstone River in Massachusetts suggests that the very shallow depth of water table and associated thin unsaturated zone at the site cause the aquifer to behave like a confined aquifer (negligible specific yield). This finding is consistent with previous studies that have shown that the effective specific yield of an unconfined aquifer approaches zero when the capillary fringe, where sediment pores are saturated by tension, extends to land surface. Under this condition, the aquifer's response is determined by elastic storage only. Estimates of horizontal and vertical hydraulic conductivity, specific yield, specific storage, and recharge for a water-table aquifer adjacent to the Cedar River in eastern Iowa, determined by the use of analytical methods, are in close agreement with those estimated by use of a more complex, multilayer numerical model of the aquifer. Streambank leakance of the semipervious streambank materials also was estimated for the site. The streambank-leakance parameter may be considered to be a general (or lumped

  16. Geomorphologic flood-hazard assessment of alluvial fans and piedmonts

    USGS Publications Warehouse

    Field, J.J.; Pearthree, P.A.

    1997-01-01

    Geomorphologic studies are an excellent means of flood-hazard assessment on alluvial fans and piedmonts in the southwestern United States. Inactive, flood-free, alluvial fans display well developed soils, desert pavement, rock varnish, and tributary drainage networks. These areas are easily distinguished from flood-prone active alluvial fans on aerial photographs and in the field. The distribution of flood-prone areas associated with alluvial fans is strongly controlled by fanhead trenches dissecting the surface. Where fanhead trenches are permanent features cut in response to long-term conditions such as tectonic quiescence, flood-prone surfaces are situated down-slope from the mountain front and their positions are stable for thousands of years. Since the length and permanency of fanhead trenches can vary greatly between adjacent drainages, it is not appropriate to use regional generalizations to evaluate the distribution and stability of flood-hazard zones. Site-specific geomorphologic studies must be carried out if piedmont areas with a high risk of flooding are to be correctly identified and losses due to alluvial-fan flooding minimized. To meet the growing demand for trained professionals to complete geomorphologic maps of desert piedmonts, undergraduate and graduate geomorphology courses should adopt an instructional unit on alluvial-fan flood hazards that includes: 1) a review of geomorphologic characteristics that vary with surface age; 2) a basic mapping exercise; and 3) a discussion of the causes of fanhead trenching.

  17. Chemical and Isotope Composition of the Mersin-Tarsus Coastal and Hillside Aquifers

    NASA Astrophysics Data System (ADS)

    Hatipoglu, Z.; Bayari, S.; Motz, L. H.

    2006-05-01

    The chemical and isotope composition of two aquifers in southern Turkey was investigated. The two aquifers, the productive Coastal Aquifer and the less productive Hillside Aquifer, represent the groundwater system along the seacoast and the adjacent hillside of the Taurus Mountains, respectively. The Coastal Aquifer, with decreasing surface area from east to west, is comprised of Neogene sediments of a fan-delta type alluvial deposition system. The Hillside Aquifer generally is comprised of the intercalation of limestone, sandstone, claystone, marl, and conglomerate of Neogene age. In this study, the groundwater of the Mersin-Tarsus Coastal and Hillside Aquifers extending between Berdan and Karakuz streams was investigated by means of in-situ measurements and chemical analyses during 2001-2003 and isotope analyses during 2003. The groundwater temperature, pH, and specific electrical conductivity were found to range between 20-26°C, 6.4-8.6, and 385-6,890 microS/cm, respectively. In two hotwater wells, the temperature, pH, and specific electrical conductivity were between 38-40°C, 7.32-7.59, and 10,900-12,000 microS/cm. The great majority of groundwater samples belongs to the Ca-HCO3 facies, although NaHCO3, MgHCO3, NaCl, CaSO4 and NaSO4 type waters were also observed. In the hot water wells, Na and Cl comprise 85% of the total major ions. The major ion data of all periods indicate a spatially varying hydrochemistry, while point wise observations did not deviate significantly with time between periods. In a considerable number of samples, the nitrate concentration exceeded the drinking water limit, while a small number of samples had Fe and Cd values above drinking water limits. According to the assessment of chloride content, only a limited number of samples was affected by sea water intrusion. Tritium isotope data indicated that the Coastal Aquifer has a longer term groundwater residence time than the Hillside Aquifer. Stable isotope data indicated that the

  18. Application of the Basin Characterization Model to Estimate In-Place Recharge and Runoff Potential in the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

    USGS Publications Warehouse

    Flint, Alan L.; Flint, Lorraine E.

    2007-01-01

    A regional-scale water-balance model was used to estimate recharge and runoff potential and support U.S. Geological Survey efforts to develop a better understanding of water availability for the Basin and Range carbonate-rock aquifer system (BARCAS) study in White Pine County, Nevada, and adjacent areas in Nevada and Utah. The water-balance model, or Basin Characterization Model (BCM), was used to estimate regional ground-water recharge for the 13 hydrographic areas in the study area. The BCM calculates recharge by using a distributed-parameter, water-balance method and monthly climatic boundary conditions. The BCM requires geographic information system coverages of soil, geology, and topographic information with monthly time-varying climatic conditions of air temperature and precipitation. Potential evapotranspiration, snow accumulation, and snowmelt are distributed spatially with process models. When combined with surface properties of soil-water storage and saturated hydraulic conductivity of bedrock and alluvium, the potential water available for in-place recharge and runoff is calculated using monthly time steps using a grid scale of 866 feet (270 meters). The BCM was used with monthly climatic inputs from 1970 to 2004, and results were averaged to provide an estimate of the average annual recharge for the BARCAS study area. The model estimates 526,000 acre-feet of potential in-place recharge and approximately 398,000 acre-feet of potential runoff. Assuming 15 percent of the runoff becomes recharge, the model estimates average annual ground-water recharge for the BARCAS area of about 586,000 acre-feet. When precipitation is extrapolated to the long-term climatic record (1895-2006), average annual recharge is estimated to be 530,000 acre-feet, or about 9 percent less than the recharge estimated for 1970-2004.

  19. Alluvial channel hydraulics

    NASA Astrophysics Data System (ADS)

    Ackers, Peter

    1988-07-01

    The development and utilisation of water resources for irrigation, hydropower and public supply can be severely affected by sediment. Where there is a mature and well vegetated landscape, sediment problems may be relatively minor; but where slopes are steep and vegetation sparse, the yield of sediment from the catchment gives high concentrations in the rivers. In utilising these resources, for whatever purpose, an understanding of the hydraulics of alluvial channels is vital. The regime of any conveyance channel in alluvium depends on the interrelationships of sediment transport, channel resistance and bank stability. The regime concept was originally based on empirical relations obtained from observations from canal systems in the Indian subcontinent, and for many years was surrounded by a certain degree of mystique and much scepticism from academics. In more recent years the unabashed empiricism of the original method has been replaced by process-based methods, which have also served as broad confirmation of the classic regime formulae, including their extension to natural channels and meandering channels. The empirical approach to the hydraulics of alluvial channels has thus been updated by physically based formulae for sediment transport and resistance, though there remains some uncertainty about the third function to complete the definition of slope and geometry. Latest thoughts in this respect are that the channel seeks a natural optimum state. Physical modelling using scaled down representations of rivers and estuaries has been used for almost a century, but it requires the correct simulation of the relevant processes. The coming of a better understanding of the physics of sediment transport and the complexity of alluvial channel roughness leads to the conclusion that only in very restricted circumstances can scale models simulate closely the full-size condition. However, the quantification of these processes has been instrumental in the development of

  20. Digital data sets that describe aquifer characteristics of the Central Oklahoma Aquifer in central Oklahoma

    USGS Publications Warehouse

    Runkle, D.L.; Christenson, S.C.; Rea, Alan

    1997-01-01

    ARC/INFO export files The data sets in this report include digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Central Oklahoma aquifer in central Oklahoma. This area encompasses all or part of Cleveland, Lincoln, Logan, Oklahoma, Payne, and Pottawatomie Counties. The Central Oklahoma aquifer includes the alluvial and terrace deposits along major streams, the Garber Sandstone and Wellington Formations, and the Chase, Council Grove, and Admire Groups. The Quaternary-age alluvial and terrace deposits consist of unconsolidated clay, silt, sand, and gravel. The Permian-age Garber Sandstone and Wellington Formations consist of sandstone with interbedded siltstone and mudstone. The Permian-age Chase, Council Grove, and Admire Groups consist of sandstone, shale, and thin limestone. The Central Oklahoma aquifer underlies about 3,000 square miles of central Oklahoma where the aquifer is used extensively for municipal, industrial, commercial, and domestic water supplies. Most of the usable ground water within the aquifer is from the Garber Sandstone and Wellington Formations. Substantial quantities of usable ground water also are present in the Chase, Council Grove, and Admire Groups, and in alluvial and terrace deposits associated with the major streams. The aquifer boundaries, hydraulic conductivity and recharge values, and ground-water level elevation contours are from previously published reports.

  1. Hydraulic processes on alluvial fans

    SciTech Connect

    French, R.H.

    1987-01-01

    Alluvial fans are among the most prominent landscape features in the American Southwest and throughout the semi-arid and arid regions of the world. The importance of developing a qualitative and quantitative understanding of the hydraulic processes which formed, and which continue to modify, these features derives from their rapid and significant development over the past four decades. As unplanned urban sprawl moved from valley floors onto alluvial fans, the serious damage incurred from infrequent flow events has dramatically increased. This book presents a discussion of our current and rapidly expanding knowledge of hydraulic processes on alluvial fans. It addresses the subject from a multidisciplinary viewpoint, acquainting the reader with geological principles pertinent to the analysis of hydraulic processes on alluvial fans.

  2. Comparison of subsurface and surface runoff phosphorus transport rates in alluvial floodplains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) loading to streams can occur by both surface runoff and subsurface transport. Although surface runoff is often considered the dominant pathway, groundwater P concentrations in alluvial aquifers can be significant, especially in preferential flow paths (PFPs). The objectives of this re...

  3. HYDRAULIC ANALYSIS OF BASE-FLOW AND BANK STORAGE IN ALLUVIAL STREAMS

    EPA Science Inventory

    This paper presents analytical solutions, which describe the effect of time-variable net recharge (net accretion to water table) and bank storage in alluvial aquifers on the sustenance of stream flows during storm and inter-storm events. The solutions relate the stream discharge,...

  4. Application of Hydraulic Tomography to Shallow Alluvial Sediments: A Case Study

    NASA Astrophysics Data System (ADS)

    Gawad, H. J.; Yeh, T. J.

    2013-12-01

    It is well known aquifer heterogeneity can have a strong effect on aquifer response to pumping, yet it is still common for aquifers to be conceptualized as homogeneous. In this study, hydraulic tomography was applied to a shallow alluvial aquifer to delineate aquifer heterogeneity. As piezometers used for this analysis are fully screened, heterogeneous transmissivity estimates are two dimensional and represent a vertically averaged estimate at each model cell. The average saturated thickness of the alluvial aquifer under investigation increased by 46% over a 2 month period in response to a large precipitation event, therefore analysis of aquifer heterogeneity was conducted before and after the increase in saturated aquifer thickness to evaluate vertical heterogeneity. Analysis was completed using groundwater level and pumping rate information collected during normal wellfield operations thus eliminating the need to interrupt wellfield function. Initially one stable configuration of active pumping rate and groundwater level information was used to evaluate aquifer heterogeneity, and then 2 additional configurations were added in an attempt to refine the estimate. Results show that locations of likely high and low zones of transmissivity vary as saturated aquifer thickness increases. Forward simulations were then run using heterogeneous transmissivity estimates and a homogeneous transmissivity estimate from a traditional pumping test. The impact of noise in the groundwater level information associated with additional pumping configurations outweighed variation in aquifer response leading to deterioration in results from forward simulations carried out using heterogeneous transmissivity estimates. However, all groundwater level estimates generated using heterogeneous transmissivity estimates are better than estimates made using the traditional homogeneous approach. These results imply that aquifer parameter analysis can be conducted without interrupting normal

  5. Fast Oxidation Processes in a Naturally Reduced Aquifer Zone Caused by Dissolved Oxygen

    NASA Astrophysics Data System (ADS)

    Davis, J. A.; Jemison, N. E.; Williams, K. H.; Hobson, C.; Bush, R. P.

    2014-12-01

    The occurrence of naturally reduced zones is quite common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. The naturally reduced zones are heterogeneously dispersed in such aquifers and are characterized by high concentrations of organic carbon and reduced phases, including iron sulfides and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases that are found in association with these natural reducing zones, although there is little understanding of the relative importance of various potential oxidants. Three field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO wherein groundwater associated with naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in these field systems if supplied to the naturally reduced zones. Small concentrations of nitrate were also observed in the previously nitrate-free groundwater, and Fe(II) decreased to the detection limit. These results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS) rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table, and seasonal variations

  6. Large Alluvial Fans on Mars

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.; Howard, Alan D.

    2004-01-01

    Several dozen distinct alluvial fans, 10 to greater than 40 km long downslope are observed exclusively in highlands craters. Within a search region between 0 deg. and 30 deg. S, alluvial fan-containing craters were only found between 18 and 29 S, and they all occur at around plus or minus 1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form three distinct clusters. Fans typically descend greater than 1 km from where they disgorge from their alcoves. Longitudinal profiles show that their surfaces are very slightly concave with a mean slope of 2 degrees. Many fans exhibit very long, narrow low-relief ridges radially oriented down-slope, often branching at their distal ends, suggestive of distributaries. Morphometric data for 31 fans was derived from MOLA data and compared with terrestrial fans with high-relief source areas, terrestrial low gradient alluvial ramps in inactive tectonic settings, and older Martian alluvial ramps along crater floors. The Martian alluvial fans generally fall on the same trends as the terrestrial alluvial fans, whereas the gentler Martian crater floor ramps are similar in gradient to the low relief terrestrial alluvial surfaces. For a given fan gradient, Martian alluvial fans generally have greater source basin relief than terrestrial fans in active tectonic settings. This suggests that the terrestrial source basins either yield coarser debris or have higher sediment concentrations than their Martian counterpoints. Martian fans and Basin and Range fans have steeper gradients than the older Martian alluvial ramps and terrestrial low relief alluvial surfaces, which is consistent with a supply of coarse sediment. Martian fans are relatively large and of low gradient, similar to terrestrial fluvial fans rather than debris flow fans. However, gravity scaling uncertainties make the flow regime forming Martian fans uncertain. Martian fans, at least those in Holden crater, apparently

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Water resources of Rockland County, New York, 2005-07, with emphasis on the Newark Basin Bedrock Aquifer

    USGS Publications Warehouse

    Heisig, Paul M.

    2011-01-01

    Concerns over the state of water resources in Rockland County, NY, prompted an assessment of current (2005-07) conditions. The investigation included a review of all water resources but centered on the Newark basin aquifer, a fractured-bedrock aquifer over which nearly 300,000 people reside. Most concern has been focused on this aquifer because of (1) high summer pumping rates, with occasional entrained-air problems and an unexplained water-level decline at a monitoring well, (2) annual withdrawals that have approached or even exceeded previous estimates of aquifer recharge, and (3) numerous contamination problems that have caused temporary or long-term shutdown of production wells. Public water supply in Rockland County uses three sources of water in roughly equal parts: (1) the Newark basin sedimentary bedrock aquifer, (2) alluvial aquifers along the Ramapo and Mahwah Rivers, and (3) surface waters from Lake DeForest Reservoir and a smaller, new reservoir supply in the Highlands part of the county. Water withdrawals from the alluvial aquifer in the Ramapo River valley and the Lake DeForest Reservoir are subject to water-supply application permits that stipulate minimum flows that must be maintained downstream into New Jersey. There is a need, therefore, at a minimum, to prevent any loss of the bedrock-aquifer resource--to maintain it in terms of both sustainable use and water-quality protection. The framework of the Newark basin bedrock aquifer included characterization of (1) the structure and fracture occurrence associated with the Newark basin strata, (2) the texture and thickness of overlying glacial and alluvial deposits, (3) the presence of the Palisades sill and associated basaltic units on or within the Newark basin strata, and (4) the streams that drain the aquifer system. The greatest concern regarding sustainability of groundwater resources is the aquifer response to the seasonal increase in pumping rates from May through October (an average increase

  9. A refined characterization of the alluvial geology of yucca flat and its effect on bulk hydraulic conductivity

    USGS Publications Warehouse

    Phelps, G.A.; Halford, K.J.

    2011-01-01

    In Yucca Flat, on the Nevada National Security Site in southern Nevada, the migration of radionuclides from tests located in the alluvial deposits into the Paleozoic carbonate aquifer involves passage through a thick, heterogeneous section of late Tertiary and Quaternary alluvial sediments. An understanding of the lateral and vertical changes in the material properties of the alluvial sediments will aid in the further development of the hydrogeologic framework and the delineation of hydrostratigraphic units and hydraulic properties required for simulating groundwater flow in the Yucca Flat area. Previously published geologic models for the alluvial sediments within Yucca Flat are based on extensive examination and categorization of drill-hole data, combined with a simple, data-driven interpolation scheme. The U.S. Geological Survey, in collaboration with Stanford University, is researching improvements to the modeling of the alluvial section, incorporating prior knowledge of geologic structure into the interpolation method and estimating the uncertainty of the modeled hydrogeologic units.

  10. Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium

    NASA Astrophysics Data System (ADS)

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, David; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-11-01

    Coal seam gas (CSG) production can have an impact on groundwater quality and quantity in adjacent or overlying aquifers. To assess this impact we need to determine the background groundwater chemistry and to map geological pathways of hydraulic connectivity between aquifers. In south-east Queensland (Qld), Australia, a globally important CSG exploration and production province, we mapped hydraulic connectivity between the Walloon Coal Measures (WCM, the target formation for gas production) and the overlying Condamine River Alluvial Aquifer (CRAA), using groundwater methane (CH4) concentration and isotopic composition (δ13C-CH4), groundwater tritium (3H) and dissolved organic carbon (DOC) concentration. A continuous mobile CH4 survey adjacent to CSG developments was used to determine the source signature of CH4 derived from the WCM. Trends in groundwater δ13C-CH4 versus CH4 concentration, in association with DOC concentration and 3H analysis, identify locations where CH4 in the groundwater of the CRAA most likely originates from the WCM. The methodology is widely applicable in unconventional gas development regions worldwide for providing an early indicator of geological pathways of hydraulic connectivity.

  11. Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium

    PubMed Central

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, David; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-01-01

    Coal seam gas (CSG) production can have an impact on groundwater quality and quantity in adjacent or overlying aquifers. To assess this impact we need to determine the background groundwater chemistry and to map geological pathways of hydraulic connectivity between aquifers. In south-east Queensland (Qld), Australia, a globally important CSG exploration and production province, we mapped hydraulic connectivity between the Walloon Coal Measures (WCM, the target formation for gas production) and the overlying Condamine River Alluvial Aquifer (CRAA), using groundwater methane (CH4) concentration and isotopic composition (δ13C-CH4), groundwater tritium (3H) and dissolved organic carbon (DOC) concentration. A continuous mobile CH4 survey adjacent to CSG developments was used to determine the source signature of CH4 derived from the WCM. Trends in groundwater δ13C-CH4 versus CH4 concentration, in association with DOC concentration and 3H analysis, identify locations where CH4 in the groundwater of the CRAA most likely originates from the WCM. The methodology is widely applicable in unconventional gas development regions worldwide for providing an early indicator of geological pathways of hydraulic connectivity. PMID:26530701

  12. Stochastic modeling of transient stream aquifer interaction with the nonlinear Boussinesq equation

    NASA Astrophysics Data System (ADS)

    Srivastava, Kirti; Serrano, Sergio E.; Workman, S. R.

    2006-09-01

    SummaryIn this article the effect of highly fluctuating stream stage on the adjacent alluvial valley aquifer is studied with a new analytical solution to the nonlinear transient groundwater flow equation subject to stochastic conductivity and time varying boundary conditions. A random conductivity field with known correlation structure represents uncertain heterogeneity. The resulting nonlinear stochastic Boussinesq equation is solved with the decomposition method. New expressions for the mean of the hydraulic head and its variance distribution are given. The procedure allows for the calculation of the mean head and error bounds in real situations when a limited sample allows the estimation of the conductivity mean and correlation structure only. Under these circumstances, the usual assumptions of a specific conductivity probability distribution, logarithmic transformation, small perturbation, discretization, or Monte Carlo simulations are not possible. The solution is verified via an application to the Scioto River aquifer in Ohio, which suffers from periodic large fluctuations in river stage from seasonal flooding. Predicted head statistics are compared with observed heads at different monitoring wells across the aquifer. Results show that the observed transient water table elevation in the observation well lies in the predicted mean plus or minus one standard deviation bounds. The magnitude of uncertainty in predicted head depends on the statistical properties of the conductivity field, as described by its coefficient of variability and its correlation length scale.

  13. High resolution imaging of aquifer properties using full-waveform GPR tomography

    NASA Astrophysics Data System (ADS)

    Gueting, N.; Klotzsche, A.; Van Der Kruk, J.; Vanderborght, J.; Vienken, T.; Vereecken, H.; Englert, A.

    2015-12-01

    Highly resolved characterization of the spatial distribution of aquifer properties is critical for the accurate prediction of groundwater flow and transport. Here, we test the value of using full-waveform inversion of cross-borehole ground penetrating radar (GPR) data for alluvial aquifer characterization. Our study is carried out at the Krauthausen test site, where several field and modelling studies, conducted over the last decades, have yielded a rich set of information that provides excellent opportunities to test and validate novel methods. We apply a full-waveform inversion to analyze GPR data acquired along 15 individual tomographic crosshole planes. By stitching together the tomographic images for adjacent crosshole planes, we are able to image the spatial distribution of subsurface electrical properties (dielectric permittivity, electrical conductivity) at the decimeter scale along transects of several tens of meters length. Although each crosshole plane was inverted separately, consistent spatial structures in the tomographic images are obtained where planes intersect, which indicates robust inversion results. The GPR results are confirmed by independent direct-push porosity logs, which show a strong correlation with porosity estimates derived from GPR using the Complex Refractive Index Model (CRIM). Compared with traditional ray-based inversion techniques, which are limited in resolution, the full-waveform inversion is found to improve the reconstruction of abrupt changes and fine-scale variations in porosity. Based on the GPR results, additional cone penetration tests (CPT) and direct-push injection logs (DPIL) have recently been measured at selected crosshole plane locations. Preliminary comparison with the GPR results indicates that the spatial variations in GPR permittivity and electrical conductivity match the major changes in lithology and hydraulic conductivity obtained from CPT and DPIL. In conclusion, our study suggests that full

  14. Historical Ground-Water Development in the Salinas Alluvial Fan Area, Salinas, Puerto Rico, 1900-2005

    USGS Publications Warehouse

    Rodriguez, Jose M.; Gómez-Gómez, Fernando

    2008-01-01

    The Salinas alluvial fan area has historically been one of the most intensively used agricultural areas in the South Coastal Plain of Puerto Rico. Changes in agricultural practices and land use in the Salinas alluvial fan have also caused changes in the geographic distribution of ground-water withdrawals from the alluvial aquifer. As a result, the ground-water balance and ground-water flow pattern have changed throughout the years and may explain the presence of saline ground water along parts of the coast at present. By providing a reconstruction of historical ground-water development in the Salinas alluvial fan area, from the initial years of aquifer development at about 1900 to the most recent conditions existing in 2005, water resources managers and planners can use the results of the analysis for a more complete understanding of aquifer conditions especially pertaining to water quality. This study effort was conducted by the U.S. Geological Survey in cooperation with the Puerto Rico Department of Natural and Environmental Resources as a contribution in the management of the Jobos Bay National Estuarine Research Reserve. The study area encompasses about 20 mi2 (square miles) of the extensive South Coastal Plain alluvial aquifer system (fig. 1). The study area is bounded to the north by foothills of the Cordillera Central mountain chain, to the south by the Caribbean Sea, and to the east and west by the Rio Nigua de Salinas and the Quebrada Aguas Verdes, respectively. Fan-delta and alluvial deposits contain the principal aquifers in the study area.

  15. Oxidation of naturally reduced uranium in aquifer sediments by dissolved oxygen and its potential significance to uranium plume persistence

    NASA Astrophysics Data System (ADS)

    Davis, J. A.; Smith, R. L.; Bohlke, J. K.; Jemison, N.; Xiang, H.; Repert, D. A.; Yuan, X.; Williams, K. H.

    2015-12-01

    The occurrence of naturally reduced zones is common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. Such reduced zones are usually heterogeneously dispersed in these aquifers and characterized by high concentrations of organic carbon, reduced mineral phases, and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases found in association with these reducing zones, although there is little understanding of the relative importance of various potential oxidants. Four field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO, wherein groundwater associated with the naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in such field systems if supplied to the naturally reduced zones. Dissolved Fe(II) concentrations decreased to the detection limit, but increases in sulfate could not be detected due to high background concentrations. Changes in nitrogen species concentrations were variable. The results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS), rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table

  16. Integrating borehole logs and aquifer tests in aquifer characterization

    USGS Publications Warehouse

    Paillet, Frederick L.; Reese, R.S.

    2000-01-01

    Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the surficial aquifer system in and around Big Cypress National Preserve in eastern Collier County, Florida. Borehole flowmeter tests provide qualitative permeability profiles in most of 26 boreholes drilled in the Study area. Flow logs indicate the depth of transmissive units, which are correlated across the study area. Comparison to published studies in adjacent areas indicates that the main limestone aquifer of the 000000Tamiami Formation in the study area corresponds with the gray limestone aquifer in western Dade County and the water table and lower Tamiami Aquifer in western Collier County. Four strategically located, multiwell aquifer tests are used to quantify the qualitative permeability profiles provided by the flowmeter log analysis. The hydrostratigraphic model based on these results defines the main aquifer in the central part of the study area as unconfined to semiconfined with a transmissivity as high as 30,000 m2/day. The aquifer decreases in transmissivity to less than 10,000 m2/day in some parts of western Collier County, and becomes confined to the east and northeast of the study area, where transmissivity decreases to below 5000 m2/day.Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the

  17. Geohydrology of the alluvial and terrace deposits of the North Canadian River from Oklahoma City to Eufaula Lake, central Oklahoma

    USGS Publications Warehouse

    Havens, J.S.

    1989-01-01

    This investigation was undertaken to describe the geohydrology of the alluvial and terrace deposits along the North Canadian River between Lake Overholser and Eufaula Lake, an area of about 1,835 square miles, and to determine the maximum annual yield of ground water. A 1982 water-level map of the alluvial and terrace aquifer was prepared using field data and published records. Data from test holes and other data from the files of the U.S. Geological Survey and the Oklahoma Water Resources Board were used to establish the approximate thickness of the alluvial and terrace deposits. The North Canadian River from Lake Overholser, near Oklahoma City, to Eufaula Lake is paralleled by a 2- to 3-mile wide band of alluvium. Scattered terrace deposits on either side of the alluvium reach an extreme width of 8 miles. Rocks of Permian age bound the alluvial and terrace deposits from the west to the midpoint of the study area; Pennsylvanian rocks bound the alluvial and terrace deposits from that point eastward. Three major aquifers are present in the study area: the alluvial and terrace aquifer, consisting of alluvium and terrace deposits of Quaternary age in a narrow band on either side of the North Canadian River; the Garber-Wellington aquifer of Permian age, consisting of an upper unconfined zone and a lower confined zone separated by relatively impermeable shales; and the Ada-Vamoosa aquifer of Pennsylvanian age. At locations were the alluvial and terrace aquifer overlies either of the other aquifers, there is hydraulic continuity between the alluvial and terrace aquifer and the other aquifers, and water levels are the same. Most large-scale municipal and industrial pumping from the Garber-Wellington aquifer is from the lower zone and has little discernible effect upon the alluvial and terrace aquifer. The total estimated base flow of the North Canadian River for the studied reach is 264 cubic feet per second. Evapotranspiration from the basin in August is about 60 cubic

  18. Regional assessment of aquifers for thermal energy storage. Volume 1. Regions 1 through 6

    SciTech Connect

    Not Available

    1981-06-01

    This volume contains information on the geologic and hydrologic framework, major aquifers, aquifers which are suitable and unsuitable for annual thermal energy storage (ATES) and the ATES potential of the following regions of the US: the Western Mountains; Alluvial Basins; Columbia LAVA Plateau; Colorado Plateau; High Plains; and Glaciated Central Region. (LCL)

  19. Carbonate aquifers

    USGS Publications Warehouse

    Cunningham, Kevin J.; Sukop, Michael; Curran, H. Allen

    2012-01-01

    Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.

  20. Fecal Indicator and Pathogenic Bacteria and Their Antibiotic Resistance in Alluvial Groundwater of an Irrigated Agricultural Region with Dairies.

    PubMed

    Li, Xunde; Atwill, Edward R; Antaki, Elizabeth; Applegate, Olin; Bergamaschi, Brian; Bond, Ronald F; Chase, Jennifer; Ransom, Katherine M; Samuels, William; Watanabe, Naoko; Harter, Thomas

    2015-09-01

    Surveys of microbiological groundwater quality were conducted in a region with intensive animal agriculture in California, USA. The survey included monitoring and domestic wells in eight concentrated animal feeding operations (CAFOs) and 200 small (domestic and community supply district) supply wells across the region. was not detected in groundwater, whereas O157:H7 and were each detected in 2 of 190 CAFO monitoring well samples. Nonpathogenic generic and spp. were detected in 24.2% (46/190) and 97.4% (185/190) groundwater samples from CAFO monitoring wells and in 4.2% (1/24) and 87.5% (21/24) of CAFO domestic wells, respectively. Concentrations of both generic and spp. were significantly associated with well depth, season, and the type of adjacent land use in the CAFO. No pathogenic bacteria were detected in groundwater from 200 small supply wells in the extended survey. However, 4.5 to 10.3% groundwater samples were positive for generic and . Concentrations of generic were not significantly associated with any factors, but concentrations of were significantly associated with proximity to CAFOs, seasons, and concentrations of potassium in water. Among a subset of and isolates from both surveys, the majority of (63.6%) and (86.1%) isolates exhibited resistance to multiple (≥3) antibiotics. Findings confirm significant microbial and antibiotic resistance loading to CAFO groundwater. Results also demonstrate significant attenuative capacity of the unconfined alluvial aquifer system with respect to microbial transport.

  1. Carbon Budget of an Alluvial Floodplain in Northwest Montana, USA

    NASA Astrophysics Data System (ADS)

    Appling, A.; Poole, G.; Bernhardt, E. S.; Kimball, J. S.; Stanford, J.

    2009-12-01

    Alluvial floodplains can be substantial sources of carbon dioxide and sinks for particulate carbon, making them important players in the global aquatic carbon cycle. However, carbon budgets for large floodplains are poorly constrained, especially for floodplains with large hyporheic aquifers and high connectivity to the river channel. We synthesized the results of seven recent studies to construct a carbon budget for the Nyack Floodplain on the Middle Fork Flathead River in northwest Montana. For the whole floodplain, including river channel, hyporheic aquifer, and riparian soils and vegetation, estimated carbon losses exceed inputs by 9.1 gC m-3 yr-1. The imbalance is primarily driven by microbial and invertebrate respiration in the aquifer (8.4 and 0.3 gC m-3 yr-1, respectively). Despite the fact that these respiration rates are among the lowest reported in the literature, they dwarf other carbon inputs to the floodplain: riparian NPP is 1.8 gC m-3 yr-1; in-channel NPP is less than 0.001 gC m-3 yr-1, and riverine DOC inputs (4.8 gC m-3 yr-1) are exceeded by riverine DOC losses (5.9 gC m-3 yr-1). To begin resolving the apparent carbon imbalance, we establish a reasonable range for each flux in the carbon budget and identify key uncertainties. Our results point to the need for more research in three areas: First, we can constrain the aquifer carbon cycle by quantifying riparian soil leaching, root exudate production, and plant biomass turnover. Second, we should better understand upstream inputs of organic matter, both annually and during large episodic floods. Finally, we need to explore the interacting roles of hydrologic flowpaths, sediment texture, and buried organic matter in creating patchy habitats for microbes and invertebrates in the aquifer.

  2. Interaction of various flow systems in small alpine catchments: conceptual model of the upper Gurk Valley aquifer, Carinthia, Austria

    NASA Astrophysics Data System (ADS)

    Hilberg, Sylke; Riepler, Franz

    2016-08-01

    Small alpine valleys usually show a heterogeneous hydraulic situation. Recurring landslides create temporal barriers for the surface runoff. As a result of these postglacial processes, temporal lakes form, and thus lacustrine fine-grained sedimentation intercalates with alluvial coarse-grained layers. A sequence of alluvial sediments (confined and thus well protected aquifers) and lacustrine sediments (aquitards) is characteristic for such an environment. The hydrogeological situation of fractured hard-rock aquifers in the framing mountain ranges is characterized by superficially high hydraulic conductivities as the result of tectonic processes, deglaciation and postglacial weathering. Fracture permeability and high hydraulic gradients in small-scaled alpine catchments result in the interaction of various flow systems in various kinds of aquifers. Spatial restrictions and conflicts between the current land use and the requirements of drinking-water protection represent a special challenge for water resource management in usually densely populated small alpine valleys. The presented case study describes hydrogeological investigations within the small alpine valley of the upper Gurktal (Upper Carinthia, Austria) and the adjacent Höllenberg Massif (1,772 m above sea level). Hydrogeological mapping, drilling, and hydrochemical and stable isotope analyses of springs and groundwater were conducted to identify a sustainable drinking-water supply for approximately 1,500 inhabitants. The results contribute to a conceptual hydrogeological model with three interacting flow systems. The local and the intermediate flow systems are assigned to the catchment of the Höllenberg Massif, whereas the regional flow system refers to the bordering Gurktal Alps to the north and provides an appropriate drinking water reservoir.

  3. Analysis of alluvial hydrostratigraphy using indicator geostatistics, with examples from Santa Clara Valley, California

    SciTech Connect

    1995-03-01

    Current trends in hydrogeology seek to enlist sedimentary concepts in the interpretation of permeability structures. However, existing conceptual models of alluvial deposition tend to inadequately account for the heterogeneity caused by complex sedimentological and external factors. This dissertation presents three analyses of alluvial hydrostratigraphy using indicator geostatistics. This approach empirically acknowledges both the random and structured qualities of alluvial structures at scales relevant to site investigations. The first analysis introduces the indicator approach, whereby binary values are assigned to borehole-log intervals on the basis of inferred relative permeability; it presents a case study of indicator variography at a well-documented ground-water contamination site, and uses indicator kriging to interpolate an aquifer-aquitard sequence in three dimensions. The second analysis develops an alluvial-architecture context for interpreting semivariograms, and performs comparative variography for a suite of alluvial sites in Santa Clara Valley, California. The third analysis investigates the use of a water well perforation indicator for assessing large-scale hydrostratigraphic structures within relatively deep production zones.

  4. Surface water?groundwater interactions in an alluvial plain: Chemical and isotopic systematics

    NASA Astrophysics Data System (ADS)

    Négrel, Ph.; Petelet-Giraud, E.; Barbier, J.; Gautier, E.

    2003-06-01

    Our work on the Loire River forms part of a French National Research Program dedicated to wetlands and aims to better understand the global functioning of the system from the hydrological, geochemical, ecological and sociological aspects. The present study, using a coupled hydrological and geochemical (stable and Sr isotopes) approach, focuses on the 'Soulangy' site with its secondary anastomosing channels just below the confluence of the Loire and Allier rivers, and also on the 'Dorna``nt' site with two unconnected oxbow lakes 50 km upstream of the confluence. The stable isotopes of water ( δ18O, δ2H) show that the alluvial (or riverbank) aquifer feeds the Loire River during the summer, but is not recharged by the river during flood periods in the winter; the alluvial groundwater thus has a purely local origin from precipitation. The major elements reveal an anthropogenic input of Cl and more importantly of NO 3, especially near farms. The 87Sr/ 86Sr isotopes identify different groundwater layers in the alluvium, i.e. an upper and a lower alluvial aquifer, and a perched aquifer at Dornant, that have relatively complex relationships with the surface water. The two main rivers (Loire and Allier) present distinct geochemical characteristics reflecting the different lithologies that they drain upstream. In addition, the secondary channels, lying parallel to the Loire main stream at the Soulangy site, give different geochemical signatures, which shows that they are not fed by the same overflows of the Loire; they are more-or-less well connected to the upper level of the alluvial plain, and a longitudinal study of one of these channels has revealed a Loire River influence progressively replaced by a water contribution from the upper alluvial aquifer. Similarly, the two oxbow lakes at the Dornant site are not supplied by the same water during the summer months. A conceptual scheme of the Loire hydrosystem based on δ18O and 87Sr/ 86Sr suggests that the isotopic

  5. Recharge of shallow aquifers through two ephemeral-stream channels in northeastern Wyoming, 1982-1983

    USGS Publications Warehouse

    Lenfest, L.W.

    1987-01-01

    Quantifying the recharge from ephemeral streams to alluvial and bedrock aquifers will help evaluate the effects of surface mining on alluvial valley floors in Wyoming. Two stream reaches were chosen for study in the Powder River basin. One reach was located along the North Fork Dry Fork Cheyenne River near Glenrock, Wyoming, and the other reach was located along Black Thunder Creek near Hampshire, Wyoming. The reach along the North Fork Dry Fork Cheyenne River was instrumented with 3 gaging stations to measure streamflow and with 6 observation wells to measure groundwater level fluctuations in alluvial and bedrock aquifers in response to streamflow. The 3 streamflow gaging stations were located within the 2.5-mi study reach to measure the approximate gain or loss of discharge along the reach. Computed streamflow losses ranged from 0.43 acre-ft/mi on July 9 , 1982, to 1.44 acre-ft/mi on August 9, 1982. The observation wells completed only in the alluvial aquifer were dry during flow in the North Fork Dry Fork Cheyenne River, whereas water levels in half of the observation wells completed in the bedrock aquifers or the alluvial and bedrock aquifers rose in response to flow in the North Fork Dry Fork Cheyenne River. Groundwater recharge on August 9, 1982, was calculated using a convolution technique using groundwater levels at the upstream site and was estimated to be 26.5 acre-ft/mi. The reach along Black Thunder Creek was instrumented with one gaging station to measure streamflow and with 4 observation wells to measure water level response in alluvial and bedrock aquifers to streamflow. Recharge to the alluvial aquifer from flow in Black Thunder Creek ranged from 3.56 to 12.4 acre-ft/mi. The recharge was estimated using the convolution technique using water level measurements in the observation wells completed in the alluvial aquifer. Water level measurements in the observation wells indicated water level rises in the alluvial and bedrock aquifers in response to

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

    SciTech Connect

    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.

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

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    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.

  9. Review of coastal-area aquifers in Africa

    NASA Astrophysics Data System (ADS)

    Steyl, G.; Dennis, I.

    2010-02-01

    The coastal aquifer systems of Africa are comprised of various geological formations. These aquifer systems consist of either folded, continental or alluvial deposits. Groundwater resource availability along the coastal areas of Africa is briefly reported and the current state of seawater intrusion has been summarized. A select number of notable examples are given to highlight the effect of saline intrusion on coastal development of cities and regional aquifers. The role of conflict resolution is briefly discussed, as well as management approaches, which include monitoring of contamination and governmental accountability. Regional cooperation is presented as a method of ensuring a sustainable water resource in an area, as well as strengthening social and political alliances.

  10. Saltwater in shallow aquifers in east-central and northeastern Louisiana and southeastern Arkansas

    USGS Publications Warehouse

    Huff, G.F.; Bonck, J.P.

    1993-01-01

    The chemistry of water from irrigation and monitor wells in east-central Louisiana indicates the presence of saltwater in the Mississippi River alluvial aquifer and the uppermost part of the Jasper aquifer system. The salinity of this groundwater makes it unsuitable for use in irrigation of salt-sensitive crops. The geochemistry of bromide (Br) and chloride (Cl) ions and strontium (Sr) isotopes indicated that this saltwater could have originated from the mixing of freshwater with briny water originating from the Carrizo-Wilcox aquifer at altitudes from 5,800 to 6,800 feet below sea level. However, in the absence of data on the concentrations of Br and Cl ions and the values of (87)Sr/(86)Sr in water from the Catahoula, Cockfield, and Sparta aquifers within the study area, no conclusive statement can be made on the origin of saltwater in the alluvial aquifer and the uppermost part of the Jasper aquifer system. Analyses of water from irrigation wells in northeastern Louisiana and southeastern Arkansas indicated the presence of saltwater in the Mississippi River alluvial aquifer. Saltwater probably moves from southern Chicot County, Arkansas, into northeastern Louisiana by flowing to the southwest along a fluvial channel eroded into the Cockfield Formation. Saltwater in the Mississippi River alluvial aquifer in northeastern Louisiana and southeastern Arkansas can be hazardous to salt-sensitive crops, such as rice, when used for irrigation. The geochemistry of Br and Cl ions indicated that saltwater in the Mississippi River alluvial aquifer of southern Chicot County in southeastern Arkansas has two geochemically distinct sources. One source, which has Br/Cl ratios less than that of modern seawater, could be derived from saltwater present in aquifers of Tertiary age; this saltwater could enter the alluvial aquifer by upward flow from below as part of the natural regional groundwater flow pattern. The other source, which has Br/Cl ratios greater than that of modern sea

  11. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    SciTech Connect

    Pickering, D.A.; Laase, A.D. ); Locke, D.A. )

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy's Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  12. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    SciTech Connect

    Pickering, D.A.; Laase, A.D.; Locke, D.A.

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy`s Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  13. Water quality in the lower Puyallup River valley and adjacent uplands, Pierce County, Washington

    USGS Publications Warehouse

    Ebbert, J.C.; Bortleson, Gilbert C.; Fuste, L.A.; Prych, E.A.

    1987-01-01

    The quality of most ground and surface water within and adjacent to the lower Puyallup River valley is suitable for most typical uses; however, some degradation of shallow groundwater quality has occurred. High concentrations of iron and manganese were found in groundwater, sampled at depths of < 40 ft, from wells tapping alluvial aquifers and in a few wells tapping deeper aquifers. Volatile and acid- and base/neutral-extractable organic compounds were not detected in either shallow or deep groundwater samples. The quality of shallow groundwater was generally poorer than that of deep water. Deep ground water (wells set below 100 ft) appears suitable as a supplementary water supply for fish-hatchery needs. Some degradation of water quality, was observed downstream from river mile 1.7 where a municipal wastewater-treatment plant discharges into the river. In the Puyallup River, the highest concentrations of most trace elements were found in bed sediments collected downstream from river mile 1.7. Median concentrations of arsenic, lead, and zinc were higher in bed sediments from small streams compared with those from the Puyallup River, possibly because the small stream drainages, which are almost entirely within developed areas, receive more urban runoff as a percentage of total flow. Total-recoverable trace-element concentrations exceeded water-quality criteria for acute toxicity in the Puyallup River and in some of the small streams. In most cases, high concentrations of total-recoverable trace elements occurred when suspended-sediment concentrations were high. Temperatures in all streams except Wapato Creek and Fife Dutch were within limits (18 C) for Washington State class A water. Minimum dissolved oxygen concentrations were relatively low at 5.6 and 2.0 mg/L, respectively, for Wapato Creek and Fife Dutch. The poorest surface-water quality, which can be characterized as generally unsuitable for fish, was in Fife Dutch, a manmade channel and therefore

  14. Ground-water flow analysis of the Mississippi Embayment aquifer system, South-Central United States

    USGS Publications Warehouse

    Arthur, J.K.; Taylor, R.E.

    1998-01-01

    The Mississippi Embayment aquifer system is composed of six regional aquifers covering about 160,000 square miles in parts of Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The flow analysis presented in this report as part of the Gulf Coast Regional Aquifer-System Analysis study pertains to five aquifers in sediments of the Wilcox and Claiborne groups of Tertiary age. In descending order, the aquifers are (1) the upper Claiborne, (2) the middle Claiborne, (3) the lower Claiborne-upper Wilcox, (4) the middle Wilcox, and (5) the lower Wilcox. The flow analysis of the sixth aquifer in the aquifer system, the Mississippi River valley alluvial aquifer in sediments of Holocene and Pleistocene age, is presented in chapter D of this Professional Paper.

  15. Tectonic setting of the San Diego formation aquifer,considered for conjunctive use storage

    NASA Astrophysics Data System (ADS)

    Keller, B.; Ward, A.

    2001-10-01

    A number of alluvial aquifers in coastal southern California are either in current use or are being considered for aquifer storage and recovery (ASR). This conjunctive-use strategy involves artificial recharge with local or imported potable water or recycled water during low-use periods and extraction during high-use periods. Most of the aquifers are alluvial fill of eroded stream channels or are alluvial fill of actively subsiding tectonic basins in the Transverse Ranges geomorphic province. In both cases, the aquifer material is relatively tectonically undisturbed since deposition, and in many cases, individual aquifer units have considerable areal extent. The San Diego Formation aquifer, which spans the international border between Alta California and Baja California, is an exception. It was deposited in a pull-apart basin in the strike-slip regime of the Rose Canyon fault zone and parallel faults, which form the boundary between the Peninsular Ranges and Continental Borderlands geomorphic provinces. The formation has been faulted, internally fractured, and locally chemically altered. The lack of continuity of individual aquifer units that is observed in aquifer studies may be associated with localized patterns of syntectonic deposition.

  16. Analysis of aquifer mineralization by paleodrainage channels

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2003-01-01

    Mineralization of groundwater resources is a problem in south-central Kansas, due to the penetration of saline water from Permian bedrock formations into the overlying alluvial aquifer. One of the mechanisms involved in the mineralization involves small bedrock features of high permeability located in places occupied by streams and rivers in past geological eras. These geological features are termed 'paleodrainage channels'. The permeability of the overlying aquifer can be significantly smaller than that of the channel fill material. The comparatively fast migration of saline water through these channels of high permeability is associated with the transfer of minerals into the overlying freshwater aquifer. This study applies a set of boundary layer approaches to quantify the process of mineral transfer from the channels into the aquifer. The methods used in the present study provide quick estimation and evaluation of the dilution of the channel flow, as well as mineral concentration profile changes in the mineralized zone created in the overlying aquifer. More generally, the method can also be useful for the analysis and evaluation of various types of groundwater contamination in heterogeneous aquifers. The application of the method is exemplified by a complete set of calculations characterizing the possible mineralization process at a specific channel in south central Kansas. Sensitivity analyses are performed and provide information about the importance of the various parameters that affect the mineralization process. Some possible scenarios for the aquifer mineralization phenomena are described and evaluated. It is shown that the channel mineralization may create either several stream tubes of the aquifer with high mineral concentration, or many stream tubes mineralized to a lesser extent. Characteristics of these two patterns of aquifer mineralization are quantified and discussed. ?? 2003 Published by Elsevier Science B.V.

  17. Aquifer properties determined from two analytical solutions

    SciTech Connect

    Chen, X.; Ayers, J.F.

    1998-09-01

    Many ground water flow and contaminant transport studies involve unconfined aquifers. Determination of reliable hydraulic properties of unconfined aquifers is therefore important. In the analysis of pumping test data, the quality of the determined aquifer parameters can be greatly improved by using a proper model of the aquifer system. Moench (1995) provided an analytical solution for flow to a well partially penetrating an unconfined aquifer. His solution, in contrast to the Neuman solution (1974), accounts for the noninstantaneous decline of the water table (delayed yield). Consequently, the calculated drawdown in these two solutions is different under certain circumstances, and this difference may therefore affect the computation of aquifer properties from pumping test data. This paper uses an inverse computational method to calculate four aquifer parameters as well as a delayed yield parameter, {alpha}{sub 1}, from pumping test data using both the Neuman (1974) and Moench (1995) solutions. Time-drawdown data sets from a pumping test in an unconfined alluvial aquifer near Grand Island, Nebraska, were analyzed. In single-well analyses, horizontal hydraulic conductivity values derived from the Moench solution are lower, but vertical hydraulic conductivity values are higher than those calculated from the Neuman solution. However, the hydraulic conductivity values in composite-well analyses from both solutions become very close. Furthermore, the Neuman solution produces similar hydraulic conductivity values in the single-well and composite-well analyses, but the Moench solution does not. While variable {alpha}{sub 1} seems to play a role in affecting the computation of aquifer parameters in the single-well analysis, a much smaller effect was observed in the composite-well analysis.

  18. Modern and ancient alluvial fan deposits

    SciTech Connect

    Nilsen, T.H.

    1985-01-01

    Understanding the structure and depositional processes of alluvial fans (river outwash deposits) has a special interest for those involved with the exploration of petroleum and many minerals. This collection of facsimile reprints of significant and classical research papers sheds new light on the subject. This reference covers the stratigraphy, sedimentology, and depositional processes of modern and ancient alluvial fans. Geographical areas considered include Arctic Canada, the American Southwest, Australia, Wyoming, Norway, and Spain. It includes a state-of-the-art introduction by the editor along with commentaries on all the papers included, a master author citation index and a subject index, and a chronological listing of early studies of alluvial fans.

  19. Alluvial plain dynamics in the southern Amazonian foreland basin

    NASA Astrophysics Data System (ADS)

    Lombardo, Umberto

    2016-05-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays and sheet sands triggered by above-normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all 12 tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. The data suggest that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid-to-late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a yearly to decadal timescale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  20. Alluvial plain dynamics in the southern Amazonian foreland basin

    NASA Astrophysics Data System (ADS)

    Lombardo, U.

    2015-10-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays triggered by above normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all the twelve tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. I found that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid- to late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a year to decade time scale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  1. Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

    USGS Publications Warehouse

    Abbott, Marvin M.; Runkle, D.L.; Rea, Alan

    1997-01-01

    Nonproprietary format files This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Vamoosa-Ada aquifer in east-central Oklahoma. The Vamoosa-Ada aquifer is an important source of water that underlies about 2,320-square miles of parts of Osage, Pawnee, Payne, Creek, Lincoln, Okfuskee, and Seminole Counties. Approximately 75 percent of the water withdrawn from the Vamoosa-Ada aquifer is for municipal use. Rural domestic use and water for stock animals account for most of the remaining water withdrawn. The Vamoosa-Ada aquifer is defined in a ground-water report as consisting principally of the rocks of the Late Pennsylvanian-age Vamoosa Formation and overlying Ada Group. The Vamoosa-Ada aquifer consists of a complex sequence of fine- to very fine-grained sandstone, siltstone, shale, and conglomerate interbedded with very thin limestones. The water-yielding capabilities of the aquifer are generally controlled by lateral and vertical distribution of the sandstone beds and their physical characteristics. The Vamoosa-Ada aquifer is unconfined where it outcrops in about an 1,700-square-mile area. Most of the lines in the aquifer boundary, hydraulic conductivity, and recharge data sets were extracted from published digital surficial geology data sets based on a scale of 1:250,000, and represent geologic contacts. Some of lines in the data sets were interpolated in areas where the Vamoosa-Ada aquifer is overlain by alluvial and terrace deposits near streams and rivers. These data sets include only the outcrop area of the Vamoosa-Ada aquifer and where the aquifer is overlain by alluvial and terrace deposits. The hydraulic conductivity value and recharge rate are from a ground-water report about the Vamoosa-Ada aquifer. The water-level elevation contours were digitized from a mylar map, at a scale of 1:250,000, used to publish a plate in a ground-water report about the Vamoosa

  2. Dispersion in alluvial convergent estuaries

    NASA Astrophysics Data System (ADS)

    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.

  3. Geometry and evolution of a syntectonic alluvial fan, Southern Pyrenees

    SciTech Connect

    Arminio, J.F. ); Nichols, G.J. )

    1993-02-01

    Syntectonic alluvial fans formed on the northern margin of the Ebro Foreland Basin along the South Pyrenean thrust front during late orogenic thrust movements in the late Oligocene/early Miocene. The present-day geometry, structural relations and sedimentology of one of these fans, the Aguero fan in the province of Huesca, Spain, were studied. Field observations of the architecture of depositional facies and the geometries of syn-tectonic folds and unconformities indicate that the Aguero fan formed as the result of several phases of sedimentation which were primarily controlled by periods of tectonic activity and quiescence. The syntectonic unconformities and growth folds in the fan deposits provide a detailed record of the evolution of a fan adjacent to an active thrust front. Using a computer program to simulate sedimentation and deformation of an alluvial fan it is possible to constrain rates of both sedimentary and tectonic processes by modeling the evolution of the fan body. A facies model for the fan phases indicates that the facies change from proximal (coarse-grained, amalgamated) to distal (finger grained, stacked fining up cycles) in less than 1 km across a fan of radius estimated to be about 2 km.

  4. Hydrogeology and geochemistry of the Ogallala aquifer, Southern High Plains

    NASA Astrophysics Data System (ADS)

    Nativ, Ronit; Smith, D. Anderson

    1987-06-01

    The Ogallala aquifer, which underlies the Southern High Plains, consists of saturated sediments of the Ogallala Formation (Neogene) that are deposited mainly as a set of humid-type alluvial fans derived from the Rocky Mountains. The Ogallala aquifer, the main source of water for the High Plains of Texas and New Mexico, has been severely depleted by extensive pumpage. The hydrology and geochemistry of the aquifer are controlled by the surface topography of the underlying formations and by the thickness and permeability of the alluvial-fan deposits. Axes of three major alluvial fans trend from northwest to southeast; the fans have increased thickness and permeability compared with interfan areas. Flow lines follow the orientation of the alluvial fans. Along these major axes, the saturated section is thick and the chemical composition is relatively constant (CaHCO 3 to mixed-cationHCO 3 water, depleted in δ 18O, δD and tritium). External effects on the chemical composition are less pronounced. The aquifer is thinner and less permeable in areas between major fan axes and along the Caprock Escarpment. In these areas, groundwater can discharge from aquifers in the Cretaceous, Triassic and Permian formations into the Ogallala Formation. Cross-formational movement of water and low permeabilities in the Ogallala Formation result in varying hydrochemical facies and in isotopic compositions that differ from those of the major depositional areas. Areas where upward cross-formational flow occurs are evident by the presence of permeable contacts between the Ogallala and the underlying formations, water-level head differences and chemical and isotopic similarities. Secondary factors that locally affect the chemical composition of Ogallala Formation groundwater include contamination from evaporating saline lakes, agricultural chemicals and fertilizers and oil field brines. Impact of chemicals and brines may increase in the future because much of these contaminants may

  5. AQUIFER TRANSMISSIVITY

    EPA Science Inventory

    Evaluation of groundwater resources requires the knowledge of the capacity of aquifers to store and transmit ground water. This requires estimates of key hydraulic parameters, such as the transmissivity, among others. The transmissivity T (m2/sec) is a hydrauli...

  6. Semi-analytical solutions of groundwater flow in multi-zone (patchy) wedge-shaped aquifers

    NASA Astrophysics Data System (ADS)

    Samani, Nozar; Sedghi, Mohammad M.

    2015-03-01

    Alluvial fans are potential sites of potable groundwater in many parts of the world. Characteristics of alluvial fans sediments are changed radially from high energy coarse-grained deposition near the apex to low energy fine-grained deposition downstream so that patchy wedge-shaped aquifers with radial heterogeneity are formed. The hydraulic parameters of the aquifers (e.g. hydraulic conductivity and specific storage) change in the same fashion. Analytical or semi-analytical solutions of the flow in wedge-shaped aquifers are available for homogeneous cases. In this paper we derive semi-analytical solutions of groundwater flow to a well in multi-zone wedge-shaped aquifers. Solutions are provided for three wedge boundary configurations namely: constant head-constant head wedge, constant head-barrier wedge and barrier-barrier wedge. Derivation involves the use of integral transforms methods. The effect of heterogeneity ratios of zones on the response of the aquifer is examined. The results are presented in form of drawdown and drawdown derivative type curves. Heterogeneity has a significant effect on over all response of the pumped aquifer. Solutions help understanding the behavior of heterogeneous multi-zone aquifers for sustainable development of the groundwater resources in alluvial fans.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Evaluation of Flow Dynamics in a Karst Aquifer System at Sapanca Lake Basin (turkey) via Hydrochemical and Isotopic Data

    NASA Astrophysics Data System (ADS)

    Gunduz, O. C.; Yolcubal, I.

    2013-12-01

    Sapanca Lake, located 20 km west of Izmit bay, is a fresh water lake with tectonic origin and supplies drinking and municipal water to the region. Groundwater discharges from a karstic aquifer developed in Permo-Triassic and Late Jurassic-Early Cretaceous aged marbles and an alluvial aquifer distributed in east-west direction on the Sapanca plain play an important role in the recharge of the lake. In the Sapanca lake basin, there are numerous springs discharging (1 to 75 lt/s) from different elevations of the karstic aquifer system. Dolines, sinkholes, depression fields, and disappearing rivers developed on the southern heights of the basin are directly connected with the karstic aquifer and allow the aquifer system to show rapid recharge and discharge characteristics. In the scope of the study, 25 karst spring waters as well as 25 wells drilled in the alluvial aquifer were sampled as representatives of dry and rainy periods. Hydrochemical and isotopic (18O/2D/3H) compositions of the samples were evaluated along with the hydrogeology and the fracture analysis of the basin in order to assess the hydraulic relationship between the aquifer systems and the groundwater circulation in the basin. Results show that groundwaters from alluvial and karstic aquifers are modern water and demonstrate similar hydrochemical facies (Ca-HCO3 ve Ca+Mg-HCO3). Although showing seasonal differences, isotopic composition (18O/2D) of the karst springs resembles those of the streams and groundwaters from alluvial aquifer. This suggests that ground and surface waters feed each other periodically and characterize a mixing. Fracture analysis of the basin suggests that faulting has significant control over groundwater discharge and circulation in the karst aquifer and form discontinuities in the system, subdividing it into several aquifer sub-systems.

  9. Nucleation of Waterfalls at Fault Scarps Temporarily Shielded By Alluvial Fan Aggradation.

    NASA Astrophysics Data System (ADS)

    Malatesta, L. C.; Lamb, M. P.

    2014-12-01

    Waterfalls are important components of mountain river systems and they can serve as an agent to transfer tectonic, climatic, or authigenic signals upstream through a catchment. Retreating waterfalls lower the local base level of the adjacent hillslopes, and temporarily increase sediment delivery to the fluvial system. Their creation is often attributed to seismic ruptures, lithological boundaries, or the coalescence of multiple smaller steps. We explore here a mechanism for the nucleation of waterfalls that does not rely on sudden seismic slip but on the build-up of accumulated slip during periods of fault burial by fluvial aggradation. Alluvial fans are common features at the front of mountain ranges bound by normal or thrust faults. Climate change or internal forcing in the mountain catchment modifies the equilibrium slope of alluvial fans. When alluvial fans aggrade, they shield the active fault scarp from fluvial erosion allowing the scarp to grow undisturbed. The scarp may then be exposed when the channel incises into the fan exposing a new bedrock waterfall. We explore this mechanism analytically and using a numerical model for bedrock river incision and sediment deposition. We find that the creation of waterfalls by scarp burial is limited by three distinct timescales: 1) the critical timescale for the scarp to grow to the burial height, 2) the timescale of alluvial re-grading of the fan, and 3) the timescale of the external or internal forcing, such as climate change. The height of the waterfall is controlled by i) the difference in equilibrium alluvial-fan slopes, ii) the ratio of the respective fan and catchment sizes, iii) the catchment wide denudation rate, and iv) the fault slip rate. We test whether an individual waterfall could be produced by alluvial shielding of a scarp, and identify the tectonic, climatic, or authigenic nature of waterfalls using example field sites in the southwest United States.

  10. Digital data sets that describe aquifer characteristics of the Rush Springs Aquifer in western Oklahoma

    USGS Publications Warehouse

    Runkle, D.L.; Becker, M.F.; Rea, Alan

    1997-01-01

    This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Rush Spring aquifer in western Oklahoma. This area encompasses all or part of Blaine, Caddo, Canadian, Comanche, Custer, Dewey, Grady, Stephens, and Washita Counties. These digital data sets were developed by Mark F. Becker to use as input into a computer model that simulated ground-water flow in the Rush Springs aquifer (Mark F. Becker, U.S. Geological Survey, written commun., 1997). For the purposes of modeling the ground-water flow in the Rush Springs aquifer, Mark F. Becker (written commun., 1997) defined the Rush Springs aquifer to include the Rush Springs Formation, alluvial and terrace deposits along major streams, and parts of the Marlow Formations, particularly in the eastern part of the aquifer boundary area. The Permian-age Rush Springs Formation consists of highly cross-bedded sandstone with some interbedded dolomite and gypsum. The Rush Springs Formation is overlain by Quaternary-age alluvial and terrace deposits that consist of unconsolidated clay, silt, sand, and gravel. The Rush Springs Formation is underlain by the Permian-age Marlow Formation that consists of interbedded sandstones, siltstones, mudstones, gypsum-anhydrite, and dolomite beds (Mark F. Becker, written commun., 1997). The parts of the Marlow Formation that have high permeability and porosity are where the Marlow Formation is included as part of the Rush Springs aquifer. The Rush Springs aquifer underlies about 2,400 square miles of western Oklahoma and is an important source of water for irrigation, livestock, industrial, municipal, and domestic use. Irrigation wells are reported to have well yields greater than 1,000 gallons per minute (Mark F. Becker, written commun., 1997). Mark F. Becker created some of the aquifer boundaries, hydraulic conductivity, and recharge data sets by digitizing parts of previously published surficial geology

  11. Groundwater quality in alluvial and prolluvial areas under the influence of irrigated agriculture activities.

    PubMed

    Kovacevik, Biljana; Boev, Blazo; Panova, Vesna Zajkova; Mitrev, Sasa

    2016-12-05

    The aim of this study was to investigate the groundwater pollution from alluvial aquifers lying under surface agriculture activities in two geologically different areas: alluvial and prolluvial. The groundwater in investigated areas is neutral to alkaline (pH 7.05-8.45), and the major dissolved ions are bicarbonate and calcium. Groundwater samples from the alluvial area are characterized by nitrate concentration above the national maximum concentration limit (MCL) at 20.5% of samples [mean value (Me) 6.31 mg/L], arsenic concentrations greater than national MCL at 35.6% of investigated samples (Me 12.12 µg/L) and elevated concentrations of iron (Me 202.37 µg/L) and manganese (Me 355.22 µg/L) at 22.7% and 81% of investigated samples, respectively. Groundwater samples from the prolluvial area did not show significantly elevated concentrations of heavy metals, but the concentration of nitrate was considerably higher (Me 65.06 mg/L). Factor analysis positively correlates As with Mn and Fe, suggesting its natural origin. Nitrate was found in positive correlation with SO4(2-) and Ni but in negative with NH4(+), suggesting its anthropogenic origin and the relationship of these ions in the process of denitrification. The t-test analysis showed a significant difference between nitrate pollution of groundwater from alluvial and prolluvial areas. According to the chemical composition of groundwater, the process of denitrification is considered to be the main reason for the reduced presence of nitrate in the groundwater lying under alluvial deposits represented by chalk and sandstones. Denitrification in groundwater lying under prolluvial deposits represented by magmatic and metamorphic rock formations was not observed.

  12. Modelling Water Flow In An Alluvial Groundwater-fed Wetland

    NASA Astrophysics Data System (ADS)

    Joris, I.; Feyen, J.

    Complex hydrological interactions occur within alluvial wetlands as a result of fluxes of water to and from the river, atmospheric fluxes and groundwater interactions. The relative importance of these fluxes and their interaction are responsible for the root zone conditions, which in turn determine the potential for different types of natu- ral vegetation. In this research, field data and numerical modeling are combined to examine the water flow processes occurring in an alluvial wetland and to develop a tool to asses the sensitivity of root zone conditions to changes in hydrological bound- ary conditions. The investigated field site is a wetland along the river Dijle with a typical micro-topography with natural levees along the river and depressions further from the river. It is a highly dynamical system with ground water amplitudes ranging from 1,5 meters close to the river to 0,5 meters in the floodplain depression. Along a transect perpendicular to the river, groundwater level and soil moisture content have been monitored for a period of two years. Groundwater inflow at the site is estimated from measurements of nested piezometers, from a regional groundwater model and from recorded soil temperature profiles. Soil hydraulic parameters are measured in the laboratory on undisturbed field cores. Saturated soil moisture contents show a sys- tematic variation with distance from the river, consistent with the observed textural variation typical for alluvial plains. The SWMS-2D code for simulating water flow in two-dimensional variably saturated media is used to reconstruct pressure head and moisture content distributions along the transect. The boundary conditions of the sim- ulation domain are determined by piezometric level in the depression, river stage on the other side, the groundwater inflow from the shallow aquifer at the bottom and rainfall/evapotranspiration at the top of the domain. Scaling factors are included in the model to allow linear variations of the

  13. Retardation of arsenic transport through a Pleistocene aquifer

    PubMed Central

    van Geen, Alexander; Bostick, Benjamín C.; Trang, Pham Thi Kim; Lan, Vi Mai; Mai, Nguyen-Ngoc; Manh, Phu Dao; Viet, Pham Hung; Radloff, Kathleen; Aziz, Zahid; Mey, Jacob L.; Stahl, Mason O.; Harvey, Charles F.; Oates, Peter; Weinman, Beth; Stengel, Caroline; Frei, Felix; Kipfer, Rolf; Berg, Michael

    2013-01-01

    Groundwater drawn daily from shallow alluvial sands by millions of wells over large areas of South and Southeast Asia exposes an estimated population of over 100 million to toxic levels of arsenic (1). Holocene aquifers are the source of widespread arsenic poisoning across the region (2, 3). In contrast, Pleistocene sands deposited in this region more than ~12,000 years ago mostly do not host groundwater with high levels of arsenic. Pleistocene aquifers are increasingly used as a safe source of drinking water (4) and it is therefore important to understand under what conditions low levels of arsenic can be maintained. Here we reconstruct the initial phase of contamination of a Pleistocene aquifer near Hanoi, Vietnam. We demonstrate that changes in groundwater flow conditions and the redox state of the aquifer sands induced by groundwater pumping caused the lateral intrusion of arsenic contamination over 120 m from Holocene aquifer into a previously uncontaminated Pleistocene aquifer. We also find that arsenic adsorbs onto the aquifer sands and that there is a 16–20 fold retardation in the extent of the contamination relative to the reconstructed lateral movement of groundwater over the same period. Our findings suggest that arsenic contamination of Pleistocene aquifers in South and Southeast Asia as a consequence of increasing levels of groundwater pumping have been delayed by the retardation of arsenic transport. PMID:24025840

  14. Geochemical Effects of Induced Stream-Water and Artificial Recharge on the Equus Beds Aquifer, South-Central Kansas, 1995-2004

    USGS Publications Warehouse

    Schmidt, Heather C. Ross; Ziegler, Andrew C.; Parkhurst, David L.

    2007-01-01

    concentrations were much smaller than the drinking-water criterion and were detected at much smaller concentrations in shallow monitoring wells and diversion well water located adjacent to the stream probably because of sorption on aquifer sediment. Before and after artificial recharge, large, naturally occurring arsenic concentrations in the recharge water for the Halstead diversion well and recharge site exceeded the Maximum Contaminant Level of 10 micrograms per liter established by the U.S. Environmental Protection Agency for drinking water. Arsenic and iron concentrations decreased when water was recharged through recharge basins or a trench; however, chemical precipitation and potential biofouling eventually may decrease the artificial recharge efficiency through basins and trenches. At the Sedgwick site, chloride concentrations infrequently exceeded regulatory criteria. Large concentrations of atrazine were treated to decrease concentrations to less than regulatory criteria. Recharge of treated stream water through recharge basins avoids potentially large concentrations of arsenic and iron that exist at the Halstead diversion site. Results from a simple mixing model using chloride as a tracer indicated that the water chemistry in shallow monitoring well located adjacent to the Little Arkansas River was 80 percent of stream water, demonstrating effective recharge of the alluvial aquifer by the stream. Results also indicated that about 25 percent of the water chemistry of the diversion well water was from the shallow part of the aquifer. Additionally, diverting water through a diversion well located adjacent to the stream removed about 75 percent of the atrazine, probably through sorption to aquifer sediment, and decreased the need for additional water treatment to remove atrazine. A flow and solute-transport model was developed using water-level and chloride concentration data to simulate and better evaluate the quantity of stream-water flow to the p

  15. Aquifer-characteristics data for West Virginia

    USGS Publications Warehouse

    Kozar, Mark D.; Mathes, Melvin V.

    2001-01-01

    Specific-capacity, storage-coefficient, and specific-yield data for wells in West Virginia were compiled to provide a data set from which transmissivity could be estimated. This data can be used for analytical and mathematical groundwater flow modeling. Analysis of available storage-coefficient and (or) specific-yield data indicates the Ohio River alluvial aquifer has a median specific yield of 0.20, which is characteristic of an unconfined aquifer. The Kanawha River alluvial aquifer has a median specific yield of 0.003, which is characteristic of a semi-confined aquifer. The median storage coefficient of fractured-bedrock aquifers is only 0.007, which is characteristic of confined aquifers. The highest median transmissivity of a specific aquifer in West Virginia occurs in Ohio River alluvium (4,800 ft2/d); the second highest occurs in Kanawha River alluvium (1,600 ft2/d). The lowest median transmissivity (23 ft2/d) is for the McKenzie-Rose Hill-Tuscarora aquifer. Rocks of Cambrian age within the Waynesboro-Tomstown-Harpers-Weverton-Loudon aquifer had a low median transmissivity of only 67 ft2/d. Other aquifers with low transmissivities include the Hampshire Formation, Brallier-Harrell Formations, Mahantango Formations, Oriskany Sandstone, and the Conococheague Formation with median transmissivities of 74, 72, 92, 82, and 92 ft2/d, respectively. All other aquifers within the State had intermediate values of transmissivity (130-920 ft2/d). The highest median transmissivities among bedrock aquifers were those for aquifers within the Pennsylvanian age Pocahontas Formation (1,200 ft2/d) and Pottsville Group (1,300 ft2/d), and the Mississippian age Mauch Chunk Group (1,300 ft2/d). These rocks crop out primarily in the southern part of the State and to a lesser extent within the Valley and Ridge Physiographic Province in West Virginia's Eastern Panhandle. The highest mean annual ground-water recharge rates within West Virginia (24.6 in.) occur within a band that extends

  16. Using direct current resistivity sounding and geostatistics to aid in hydrogeological studies in the Choshuichi alluvial fan, Taiwan.

    PubMed

    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.

  17. Arsenate adsorption by unsaturated alluvial sediments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arsenate adsorption as a function of solution arsenic concentration and solution pH was investigated on five alluvial sediments from the Antelope Valley, Western Mojave Desert, California. Arsenate adsorption increased with increasing solution pH, exhibited a maximum around pH 4 to 5, and then decr...

  18. Backwater number scaling of alluvial bed forms

    NASA Astrophysics Data System (ADS)

    Shaw, John B.; McElroy, Brandon

    2016-08-01

    The backwater number, Bw, compares the backwater length scale to the length scale of alluvial bed forms. We derive theory to show that Bw plays an important role in determining the behavior and scaling of morphodynamic systems. When Bw ≫ 1, spatial patterns in deposition and erosion derive from flow accelerations associated with changes in flow depth, and bed evolution is akin to a kinematic wave. When Bw ≪ 1, the spatial pattern of shear stress is determined by variations in energy slope, and alluvial beds experience topographic dispersion. This theory is confirmed using a numerical model and data compiled from the literature. We present a data set of Bw for bed forms ranging from dunes to river deltas, including field and experimental measurements. For field-scale measurements, we find that dunes have Bw > 49, braid bars exist in the range Bw = [7.1,17], meanders have a range Bw = [7.1,18], and river mouth deposition ranges over Bw = [7.4,29]. Further, alluvial morphologies that are easily recreated in the laboratory (dunes and avulsions) have overlapping field and laboratory Bw ranges. In contrast, alluvial forms that have traditionally been difficult to recreate (meanders and river mouth processes) have field Bw that are difficult to match in laboratory settings. Large experimental Froude numbers are shown to reduce experimental Bw and incite diffusional behavior. Finally, we demonstrate the utility of Bw scaling for estimating fundamental scales in sedimentary systems.

  19. Influence of Alluvial Morphology on Upscaled Hydraulic Conductivity.

    PubMed

    Jha, Sanjeev Kumar; Mariethoz, Gregoire; Mathews, George; Vial, John; Kelly, Bryce F J

    2016-05-01

    The hydraulic conductivity of aquifers is a key parameter controlling the interactions between resource exploitation activities, such as unconventional gas production and natural groundwater systems. Furthermore, this parameter is often poorly constrained by typical data used for regional groundwater modeling and calibration studies performed as part of impact assessments. In this study, a systematic investigation is performed to understand the correspondence between the lithological descriptions of channel-type formation and the bulk effective hydraulic conductivities at a larger scale (Kxeff , Kyeff , and Kzeff in the direction of channel cross section, along the channel and in the vertical directions, respectively). This will inform decisions on what additional data gathering and modeling of the geological system can be performed to allow the critical bulk properties to be more accurately predicted. The systems studied are conceptualized as stacked meandering channels formed in an alluvial plain, and are represented as two facies. Such systems are often studied using very detailed numerical models. The main factors that may influence Kxeff , Kyeff , and Kzeff are the proportion of the facies representing connected channels, the aspect ratio of the channels, and the difference in hydraulic conductivity between facies. Our results show that in most cases, Kzeff is only weakly dependent on the orientations of channelized structures, with the main effects coming from channel aspect ratio and facies proportion.

  20. Effects of the Biofuels Initiative on Water Quality and Quantity in the Mississippi Alluvial Plain

    NASA Astrophysics Data System (ADS)

    Welch, H. L.; Green, C. T.; Coupe, R. H.

    2010-12-01

    In the search for renewable fuel alternatives, biofuels have gained strong political momentum. In the last decade, extensive mandates, policies, and subsidies have been adopted to foster the development of a biofuels industry in the United States. The manifestation of the Biofuels Initiative in the Mississippi Delta was a 47-percent decrease in cotton acreage with a concurrent 288 percent increase in corn acreage in 2007. Because corn uses 80 percent more water for irrigation than cotton, and more nitrogen fertilizer is recommended for corn cultivation, this crop type change has implications for water quantity and quality in the Delta. Increased water use for corn is accelerating water-level declines in the Mississippi River Valley alluvial aquifer at a time when conservation is being encouraged due to concerns about sustainability. A mathematical model calibrated to existing conditions in the Delta shows that increased fertilizer applications on corn will increase the extent of nitrate movement into the alluvial aquifer. Estimates based on surface-water modeling results indicate that higher application rates of nitrogen from increased corn production increases the amount of nitrogen exported from the Yazoo River basin to the Gulf of Mexico by about 7 percent; increasing the Delta’s contribution to hypoxic conditions in the Gulf of Mexico.

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

    USGS Publications Warehouse

    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.

  2. Seismic responses of pipelines laid through alluvial valleys

    SciTech Connect

    Liang, J.W.; Jia, S.; Hou, Z.

    1995-12-31

    In this paper, dynamic characteristics of pipelines laid through alluvial valleys are analyzed. The scattering solution of SH-waves by a shallow circular alluvial valley is used to evaluate ground motion, and pipeline-soil interaction is considered. The results show that the alluvial valley has spectacular effects on dynamic behaviors of the pipelines, and for a narrow valley, damage will appear at two interfaces between the alluvial deposit and the riverbed, and for a wider valley, the damage will appear not only at two interfaces but also in the alluvial deposit, this depends on the valley width and the wavelength of incidence seismic waves.

  3. Inter-aquifer Dynamics in and Near a Confining Unit Window in Shelby County, Tennessee, USA

    NASA Astrophysics Data System (ADS)

    Gentry, R. W.; McKay, L. D.; Larsen, D.; Carmichael, J. K.; Solomon, D. K.; Thonnard, N.; Anderson, J. L.

    2003-12-01

    An interdisplinary research team is investigating the interaction between the surficial alluvial aquifer and the deeper confined Memphis aquifer in the Memphis area, Shelby County, Tennessee. Previous research has identified a window in the clay-rich, upper Claiborne confining unit that separates the two aquifers near a closed municipal landfill in east-central Shelby County, an area undergoing rapid urbanization. For this investigation, a combination of environmental tracers (tritium/helium-3), major and trace ion geochemistry, hydraulic response testing, measurement of hydraulic gradients, and groundwater flow modeling is being used to quantify recharge of young water from the alluvial aquifer through the window to the Memphis aquifer. The research will provide results to better understand how windows were formed and how they influence recharge and water quality in otherwise confined parts of the Memphis aquifer downdip of its outcrop/subcrop area. Examination of continuous core samples and geophysical logs from wells installed for the study using Rotasonic drilling methods confirmed the existence of a sand-dominated window that may be as much as 1 km in diameter in the upper Claiborne confining unit. The upper Claiborne confining unit is 15 to 20 m thick in most of the study area and is overlain by a 10 to 12 m thick alluvial aquifer. The window is interpreted to have formed as a result of depositional and incisional processes in an Eocene-age deltaic system. Hydraulic gradients of several feet exist vertically between the alluvial and Memphis aquifers within the window, indicating downward flow. Groundwater age-dates from tritium/helium-3 analyses indicate that groundwater in the window at the depth of the base of the surrounding confining unit (approximately 30 m) has an apparent age of 19.8 years, which confirms the occurrence of downward flow. Young groundwater age dates (less than 32 years) also were obtained from wells in the Memphis aquifer at confined

  4. Digital data sets that describe aquifer characteristics of the High Plains Aquifer in western Oklahoma

    USGS Publications Warehouse

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export files This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the High Plains aquifer in western Oklahoma. This area encompasses the panhandle counties of Cimarron, Texas, and Beaver, and the western counties of Harper, Ellis, Woodward, Dewey, and Roger Mills. The High Plains aquifer underlies approximately 7,000 square miles of Oklahoma and is used extensively for irrigation. The High Plains aquifer is a water-table aquifer and consists predominately of the Tertiary-age Ogallala Formation and overlying Quaternary-age alluvial and terrace deposits. In some areas the aquifer is absent and the underlying Triassic, Jurassic, or Cretaceous-age rocks are exposed at the surface. These rocks are hydraulically connected with the aquifer in some areas. The High Plains aquifer is composed of interbedded sand, siltstone, clay, gravel, thin limestones, and caliche. The proportion of various lithological materials changes rapidly from place to place, but poorly sorted sand and gravel predominate. The rocks are poorly to moderately well cemented by calcium carbonate. The aquifer boundaries, hydraulic conductivity, and recharge data sets were created by extracting geologic contact lines from published digital surficial geology maps based on a scale of 1:125,000 for the panhandle counties and 1:250,000 for the western counties. The water-level elevation contours and some boundary lines were digitized from maps in a published water-level elevation map for 1980 based on a scale of 1:250,000. The hydraulic conductivity and recharge values in this report were used as input to the ground-water flow model on the High Plains aquifer. 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

  5. Compilation and analyses of aquifer performance tests in eastern Kansas

    USGS Publications Warehouse

    Reed, T.B.; Burnett, R.D.

    1985-01-01

    Selected aquifer-test data from 36 counties in eastern Kansas were collected from numerous sources and publications in order to produce a documented compilation of aquifer tests in one report. Data were obtained chiefly from private consulting firms and from government agencies. Hydraulic properties determined included transmissivity, storage coefficient (where observation well was available), and in some cases hydraulic properties of a confining layer. The aquifers tested comprised three main types of rocks--consolidated rock deposits, glacial deposits, and alluvial deposits that include the ' Equus beds, ' an extensive alluvial deposit in south-central Kansas. The Theis recovery equation and the Cooper-Jacob modified nonequilibrium equation were the two principal solution methods used. Other methods used included the Theis nonequilibrium equation, the Hantush-Jacob equation for a leaky confined aquifer, Hantush 's modified leaky equation in which storage from a confining layer was considered, the Boulton 's delayed-yield equation. Additionally, a specific-capacity method of estimating transmissivity was used when only a single drawdown value was available. (USGS)

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

    USGS Publications Warehouse

    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

  7. Laboratory alluvial fans in one dimension.

    PubMed

    Guerit, L; Métivier, F; Devauchelle, O; Lajeunesse, E; Barrier, L

    2014-08-01

    When they reach a flat plain, rivers often deposit their sediment load into a cone-shaped structure called alluvial fan. We present a simplified experimental setup that reproduces, in one dimension, basic features of alluvial fans. A mixture of water and glycerol transports and deposits glass beads between two transparent panels separated by a narrow gap. As the beads, which mimic natural sediments, get deposited in this gap, they form an almost one-dimensional fan. At a moderate sediment discharge, the fan grows quasistatically and maintains its slope just above the threshold for sediment transport. The water discharge determines this critical slope. At leading order, the sediment discharge only controls the velocity at which the fan grows. A more detailed analysis reveals a slight curvature of the fan profile, which relates directly to the rate at which sediments are transported.

  8. Interaction of fine sediment with alluvial streambeds

    USGS Publications Warehouse

    Jobson, H.E.; Carey, W.P.

    1989-01-01

    An alluvial streambed can have a large capacity to store fine sediments that are extracted from the flow when instream concentrations are high and it can gradually release fine sediment to the flow when the instream concentrations are low. Several types of storage mechanisms are available depending on the relative size distribution of the suspended load and bed material, as well as the flow hydraulics. -from Authors

  9. Generalized sorting profile of alluvial fans

    NASA Astrophysics Data System (ADS)

    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. Experimental studies in stream-aquifer interaction along the Arkansas River in Central Kansas - Field testing and analysis

    USGS Publications Warehouse

    Sophocleous, M.; Townsend, M.A.; Vogler, L.D.; McClain, T.J.; Marks, E.T.; Coble, G.R.

    1988-01-01

    During the last several years, streamflows of a number of Kansas streams have been reduced as a result of groundwater declines. In order to better understand and quantify stream-aquifer interrelationships, an eight-day comprehensive stream-aquifer pumping test, followed by recovery monitoring, was conducted along the Arkansas River near Great Bend, Kansas. In addition to water level monitoring in numerous observation wells, streamflow data, streambed hydraulic gradients, neutron probe-based water content of dewatered sediments, water chemistry and other data were collected. The alluvial aquifer is shown to be highly transmissive (T = 1803 m2d-1) with the pumping stress (9538 m3d-1) having a radius of influence larger than 1.77 km, impacting both the aquifer levels and the streamflow in the nearby Arkansas River. Drawdown and recharge boundary effects were observed in all observation wells, including those on the opposite side of the river. The alluvial aquifer did not exhibit a water table behavior and responded as a leaky confined aquifer. A semiconfining clay layer less than 3 m thick and an additional recharge source from a nearby stream-alluvial system were the probable causes of the observed phenomena. Actual streamflow depletion is shown to be appreciably less than the computed depletion based on analytical solutions. ?? 1988.

  11. Experimental Alluvial Fan Modeling Related to Large Alluvial Fans on Mars

    NASA Astrophysics Data System (ADS)

    Kraal, E. R.; van Dijk, M.; Postma, G.

    2006-12-01

    A population of large alluvial fans has been discovered on Mars. They emanate from crater rims and deposit into crater basins. The build up of such alluvial fans requires a sustained source of flowing surface water. However, the amount of water may vary and that variation can be recorded in variations in fan surface morphology and slope. About half of the alluvial fans on Mars preserve a surface fluvial record (e.g.stream patterns, meanders, cut banks) and the majority have slopes measurable at Mars Orbiter Laser Altimeter (MOLA) resolution. We are conducting experimental modeling of alluvial fan formation using the Eurotank at Utrecht University to understand the relative importance of sediment discharge and pre-existing basin slopes on alluvial fan morphology. The Eurotank Flume Facility contains a flume 5 by 8 meters. The water discharge, sediment discharge, basin structure, and particle size can all be varied. We conduct two experiments simultaneously; the resulting fans are deposited on two 2.5 by 5 meter prepared surfaces with constant slopes of ~0.035 and ~0.045, respectively. Sediment and water discharge are held constant. Results are recorded as a combination of surface images (from video recording of fluvial processes) and digital terrain models (DTM) at a resolution of ~80 microns from photogrammetry (stereo pairs) of the entire fan apron surface. The DTM and photographic results will be integrated with data from previous experiments of fan formation over lower sloping surfaces and the combined experiments will be compared to the Martian fan population. We will compare the experimental formation of surface fluvial features similar to those observed on Mars (e.g. stream patterns) with the goal of ascertaining the amount of fluid (i.e. debris flow vs. fluvial) required to form the Martian alluvial fans. Though we are currently focusing on Martian large alluvial fans, we anticipate that there will be broad applications to many of the fans discovered on Mars

  12. Enhancements to the Mississippi Embayment Regional Aquifer Study (MERAS) groundwater-flow model and simulations of sustainable water-level scenarios

    USGS Publications Warehouse

    Clark, Brian R.; Westerman, Drew A.; Fugitt, D. Todd

    2013-01-01

    Arkansas continues to be one of the largest users of groundwater in the Nation. As such, long-term planning and management are essential to ensure continued availability of groundwater and surface water for years to come. The Mississippi Embayment Regional Aquifer Study (MERAS) model was developed previously as a tool to evaluate groundwater availability within the Mississippi embayment, which encompasses much of eastern Arkansas where the majority of groundwater is used. The Arkansas Water Plan is being updated for the first time since 1990 and serves as the State’s primary, comprehensive water-resources planning and guidance document. The MERAS model was selected as the best available tool for evaluation of specific water-use pumping scenarios that are currently being considered by the State of Arkansas. The model, developed as part of the U.S. Geological Survey Groundwater Resources Program’s assessment of the Nation’s groundwater availability, is proving to be invaluable to the State as it works toward development of a sustained yield pumping strategy. One aspect of this investigation was to evaluate multiple methods to improve the match of observed to simulated groundwater levels within the Mississippi River Valley alluvial and middle Claiborne (Sparta) aquifers in the MERAS model. Five primary methods were evaluated: (1) explicit simulation of evapotranspiration (ET), (2) upgrade of the Multi-Node Well (MNW2) Package, (3) geometry improvement within the Streamflow Routing (SFR) Package, (4) parameter estimation of select aquifer properties with pilot points, and (5) modification of water-use estimates. For the planning purposes of the Arkansas Water Plan, three scenarios were developed to evaluate potential future conditions: (1) simulation of previously optimized pumping values within the Mississippi River Valley alluvial and the middle Claiborne aquifers, (2) simulated prolonged effects of pumping at average recent (2000–5) rates, and (3) simulation

  13. Timing of alluvial fan development along the Chajnantor Plateau, Atacama Desert, northern Chile: Insights about climate variation

    NASA Astrophysics Data System (ADS)

    Cesta, J. M.; Ward, D.

    2015-12-01

    An extensive alluvial apron of coalescing gravel fans blankets the western flank of the Chajnantor Plateau in the Atacama Desert of northern Chile. Remnant alluvial surfaces, terraces, and intermittent debris flow deposits preserved in this bajada indicate multiple intervals of aggradation, incision and terrace abandonment, and deposition. The high preservation potential and sensitivity to climate shifts of the region provides a unique opportunity to elucidate the sedimentary response to climate variations at an extreme of Earth's climate. We use cosmogenic 36Cl exposure dating, aided by mapping, to establish a detailed chronology of the depositional history of the Chajnantor alluvial apron. Alluvial surfaces and gravel deposits yield cosmogenic exposure ages ranging from 20.7 ± 1.4 ka to 419.2 ± 39.6 ka. Debris flow boulders confined to modern and ancient channels yield cosmogenic exposure ages ranging from 9.3 ± 1.1 ka to 202.5 ± 19.6 ka. One localized (Qcf1) and two extensive (Qcf2 and Qcf3) abandoned alluvial fan surfaces yield cosmogenic exposure ages of ~145 ka, ~55 ka, and ~33 ka respectively. These abandonment ages coincide with periods of moraine stabilization and deglaciation on the adjacent Chajnantor Plateau. The cosmogenic exposure ages also reveal a transition from aggradation to incision during marine oxygen isotope stage II (MIS II), coincident with local deglaciation. We interpret that protracted periods of aggradation coincide with periods of increased precipitation and glacial occupation of the Chajnantor Plateau, and are punctuated by phases of incision and surface abandonment during interglacial periods. These results suggest that precipitation is the dominant mechanism driving alluvial fan formation and modulating sediment supply along the western margin of the Chajnantor Plateau.

  14. Clay sized fraction and powdered whole-rock X-ray analyses from alluvial basin deposits in central and southern New Mexico

    USGS Publications Warehouse

    Anderholm, S.K.

    1985-01-01

    As part of the study of the water quality and geochemistry of Southwest Alluvial Basins (SWAB) in parts of Colorado, New Mexico, and Texas, which is a Regional Aquifer-System Analysis (RASA) program, whole rock x-ray analysis and clay-size fraction mineralogy (x-ray) analysis of selected samples from alluvial basin deposits were done to investigate the types of minerals and clay types present in the aquifers. This was done to determine the plausible minerals and clay types in the aquifers that may be reacting with groundwater and affecting the water quality. The purpose of this report is only to present the whole rock x-ray and clay-fraction mineralogy data. Nineteen surface samples or samples from outcrop of Tertiary and Quaternary alluvial basin deposits in the central and southern Rio Grande rift were collected and analyzed. The analysis of the samples consisted of grain size analysis, and clay-size fraction mineralogy and semiquantitative analysis of the relative abundance of different clay mineral groups present. (USGS)

  15. Geohydrology and susceptibility of major aquifers to surface contamination in Alabama; Area 8

    USGS Publications Warehouse

    Scott, J.C.; Cobb, R.H.; Castleberry, R.D.

    1987-01-01

    The U.S. Geological Survey, in cooperation with the Alabama Department of Environmental Management, is conducting a series of geohydrologic studies to delineate the major aquifers and their susceptibility to contamination in Alabama. This report delineates and describes the geohydrology and susceptibility of the major aquifers to contamination in Area 8--Autauga, Chilton, Elmore, Lowndes, and Montgomery Counties. The major aquifers in the study area are the Eutaw, Gordo, and Coker aquifers of Cretaceous age. One or more of these aquifers are sources of public water supply in each of the five counties. The recharge areas for these aquifers are in Autauga, Chilton, Elmore, and Montgomery and Prattville. Maximum groundwater use in the Prattville area is more than 8 mgd (million gallons per day). Estimated maximum groundwater withdrawal for all uses in the study area is about 65 mgd. The potentiometric map of the Gordo aquifer indicates that the Alabama River may serve as a recharging boundary to the Gordo aquifer along the flood plain of the river in the Montgomery-Prattville area. The river also is acting as a recharging boundary to the Eutaw and Coker aquifers, where the potentiometric surfaces in the aquifers have been lowered. All recharge areas for the major aquifers are susceptible to contamination from the surface. However, the areas that are highly susceptible to contamination extend from Jemison to Clanton in Chilton County where the Coker aquifer generally is < 100 ft below land surface, and the flood plains of the Alabama, Coosa, and Tallapoosa Rivers, which are underlain by alluvial deposits that are in hydraulic contact with the major aquifers. Within the highly susceptible areas, the areas especially susceptible to contamination are the flood plain of the Alabama River in the Montgomery area and the flood plain of the Tallapoosa River. Pumpage from the major aquifers in this area has significantly lowered the potentiometric surface in the aquifers

  16. Dynamic Modeling of Meandering Alluvial Channels

    NASA Astrophysics Data System (ADS)

    Lan, Yongqiang

    1990-01-01

    The migration of meandering alluvial channels is investigated theoretically, numerically, and experimentally. An equation for the rate of bank erosion is derived from a two-dimensional continuity equation for sediment transport linked with the depth-averaged dynamic flow equations. A simple one-dimensional theoretical analysis of meander migration leads to a relationship between the migration rate and the relative channel curvature and sediment properties. The simple model appropriately simulates the pattern and rate of meander expansion and migrations of the White River, Indiana and the East Nishnabotna River, Iowa. Application of the one-dimensional model to sine -generated alluvial channels indicates that meander migration reaches its maximum when the relative radius of curvature reaches about 4.8, or when the sinuosity of meander approaches 1.3. A two-dimensional numerical model, DYNAMIC, which predicts both lateral and longitudinal migration of alluvial channels is then developed, based on a system of quasi -steady depth-averaged flow dynamic equations, a sediment continuity equation, and a bank erosion equation. A linear analysis of the two-dimensional model leads to a convolutional relation between the rate of meander migration and flow and sediment properties. In the two-dimensional numerical analysis, a numerical algorithm called FLOWSOL is developed to solve the flow dynamic equations. The flow algorithm is then linked to the sediment continuity equation and bank erosion equation to simulate bed deformation and bank erosion. The developed two-dimensional model is applied to calculate the velocity profiles in Rozovskii's experiments and the bed deformation and shear stress in Hooke's experiments. Good agreement is obtained between the calculated and measured velocities, shear stresses and bed profiles in all experiments. Small scaled meandering rivers are developed successfully on a floodplain with or without cohesive materials (about 3%) in a wide

  17. Controls on alluvial fan long-profiles

    USGS Publications Warehouse

    Stock, J.D.; Schmidt, K.M.; Miller, D.M.

    2008-01-01

    Water and debris flows exiting confined valleys have a tendency to deposit sediment on steep fans. On alluvial fans where water transport of gravel predominates, channel slopes tend to decrease downfan from ???0.10-0.04 to ???0.01 across wide ranges of climate and tectonism. Some have argued that this pattern reflects grain-size fining downfan such that higher threshold slopes are required just to entrain coarser particles in the waters of the upper fan, whereas lower slopes are required to entrain finer grains downfan (threshold hypothesis). An older hypothesis is that slope is adjusted to transport the supplied sediment load, which decreases downfan as deposition occurs (transport hypothesis). We have begun to test these hypotheses for alluvial fan long-profiles using detailed hydraulic and particle-size data in sediment transport models. On four alluvial fans in the western U.S., we find that channel hydraulic radiiare largely 0.5-0.9 m at fan heads, decreasing to 0.1-0.2 m at distal margins. We find that median gravel diameter does not change systematically along the upper 60%-80% of active fan channels as slope declines, so downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, channel-bed sand cover increases systematically downfan from areal fractions of <20% above fan heads to distal fan values in excess of 70%. As a result, entrainment thresholds for bed material might decrease systematically downfan, leading to lower slopes. However, current models of this effect alone tend to underpredict downfan slope changes. This is likely due to off-channel gravel deposition. Calculations that match observed fan long-profiles require an exponential decline in gravel transport rate, so that on some fans approximately half of the load must be deposited off channel every -0.20-1.4 km downfan. This leads us to hypothesize that some alluvial fan long-proffies are statements about the rate of overbank deposition of

  18. CHANNEL EVOLUTION IN MODIFIED ALLUVIAL STREAMS.

    USGS Publications Warehouse

    Simon, Andrew; Hupp, Cliff R.

    1987-01-01

    This study (a) assesses the channel changes and network trends of bed level response after modifications between 1959 and 1972 of alluvial channels in western Tennessee and (b) develops a conceptual model of bank slope development to qualitatively assess bank stability and potential channel widening. A six-step, semiquantitative model of channel evolution in disturbed channels was developed by quantifying bed level trends and recognizing qualitative stages of bank slope development. Development of the bank profile is defined in terms of three dynamic and observable surfaces: (a) vertical face (70 to 90 degrees), (b) upper bank (25 to 50 degrees), and (c) slough line (20 to 25 degrees).

  19. Geohydrology and susceptibility of major aquifers to surface contamination in Alabama, area 7

    USGS Publications Warehouse

    Mooty, W.S.

    1987-01-01

    The geohydrology and susceptibility of the seven major aquifers to surface contamination in Area 7 - Bibb, Dallas, Hale, Perry, and Wilcox Counties, are described. Aquifers in the northern part of the study area are in Paleozoic limestones and dolomite formations. Deposits in the central part of the study area are predominately of Cretaceous age and contain the Coker, Gordo, and Eutaw aquifers. Although the southern part of the study area has many deposits of Tertiary age, the Ripley Formation of Cretaceous age is the major aquifer. Contamination of any of the major aquifers is improbable because the majority of the recharge area for the primary aquifers is woodland, pasture, or farmland. Downdip from their outcrops, the major aquifers in the study area are protected from land surface contamination by relatively impermeable layers of clay and chalk. The aquifers that are highly susceptible to contamination are the ones in the limestone and dolomite formations in northern Bibb County. Sinkholes exist in the recharge area of these formations and could provide a direct link for contaminates from the land surface to the water table. An area northeast of the Selma well field is also highly susceptible to contamination. The Eutaw Formation in this area is overlain by alluvial deposits that could increase recharge to the aquifer by slowing the runoff rate of surface water. (USGS)

  20. Records of selected wells and lithologic logs of test holes, Hendry County and adjacent areas, Florida

    USGS Publications Warehouse

    Fish, John E.; Causaras, Carmen R.; O'Donnell, T. H.

    1983-01-01

    To provide water-resource information for Hendry County, Florida , geologic test holes were drilled in the surficial aquifer, and an extensive inventory was compiled of wells in the surficial aquifer and deep artesian aquifers. This report provides: (1) records for 788 selected wells and test holes including location , construction, water use, water level, chloride concentration, specific conductance, temperature, yield, hydrogen sulfide, and iron-staining problems; and (2) lithologic logs for 26 test holes ranging in depth from 90 to 650 feet. A few inventoried wells and two test holes are in adjacent parts of Collier or Glades Counties. (USGS)

  1. Macro-roughness model of bedrock-alluvial river morphodynamics

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Parker, G.; Stark, C. P.; Inoue, T.; Viparelli, E.; Fu, X.; Izumi, N.

    2014-05-01

    The 1-D saltation-abrasion model of channel bedrock incision of Sklar and Dietrich, in which the erosion rate is buffered by the surface area fraction of bedrock covered by alluvium, was a major advance over models that treat river erosion as a function of bed slope and drainage area. Their model is, however, limited because it calculates bed cover in terms of bedload sediment supply rather than local bedload transport. It implicitly assumes that as sediment supply from upstream changes, the transport rate adjusts instantaneously everywhere downstream to match. This assumption is not valid in general, and thus can give rise unphysical consequences. Here we present a unified morphodynamic formulation of both channel incision and alluviation which specifically tracks the spatiotemporal variation of both bedload transport and alluvial thickness. It does so by relating the cover fraction not to a ratio of bedload supply rate to capacity bedload transport, but rather to the ratio of alluvium thickness to a macro-roughness characterizing the bedrock surface. The new formulation predicts waves of alluviation and rarification, in addition to bedrock erosion. Embedded in it are three physical processes: alluvial diffusion, fast downstream advection of alluvial disturbances and slow upstream migration of incisional disturbances. Solutions of this formulation over a fixed bed are used to demonstrate the stripping of an initial alluvial cover, the emplacement of alluvial cover over an initially bare bed and the advection-diffusion of a sediment pulse over an alluvial bed. A solution for alluvial-incisional interaction in a channel with a basement undergoing net rock uplift shows how an impulsive increase in sediment supply can quickly and completely bury the bedrock under thick alluvium, so blocking bedrock erosion. As the river responds to rock uplift or base level fall, the transition point separating an alluvial reach upstream from an alluvial-bedrock reach downstream

  2. Macro-roughness model of bedrock-alluvial river morphodynamics

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Parker, G.; Stark, C. P.; Inoue, T.; Viparelli, E.; Fu, X.; Izumi, N.

    2015-02-01

    The 1-D saltation-abrasion model of channel bedrock incision of Sklar and Dietrich (2004), in which the erosion rate is buffered by the surface area fraction of bedrock covered by alluvium, was a major advance over models that treat river erosion as a function of bed slope and drainage area. Their model is, however, limited because it calculates bed cover in terms of bedload sediment supply rather than local bedload transport. It implicitly assumes that as sediment supply from upstream changes, the transport rate adjusts instantaneously everywhere downstream to match. This assumption is not valid in general, and thus can give rise to unphysical consequences. Here we present a unified morphodynamic formulation of both channel incision and alluviation that specifically tracks the spatiotemporal variation in both bedload transport and alluvial thickness. It does so by relating the bedrock cover fraction to the ratio of alluvium thickness to bedrock macro-roughness, rather than to the ratio of bedload supply rate to capacity bedload transport. The new formulation (MRSAA) predicts waves of alluviation and rarification, in addition to bedrock erosion. Embedded in it are three physical processes: alluvial diffusion, fast downstream advection of alluvial disturbances, and slow upstream migration of incisional disturbances. Solutions of this formulation over a fixed bed are used to demonstrate the stripping of an initial alluvial cover, the emplacement of alluvial cover over an initially bare bed and the advection-diffusion of a sediment pulse over an alluvial bed. A solution for alluvial-incisional interaction in a channel with a basement undergoing net rock uplift shows how an impulsive increase in sediment supply can quickly and completely bury the bedrock under thick alluvium, thus blocking bedrock erosion. As the river responds to rock uplift or base level fall, the transition point separating an alluvial reach upstream from an alluvial-bedrock reach downstream

  3. Unprotected karst resources in western Iran: the environmental impacts of intensive agricultural pumping on the covered karstic aquifer, a case in Kermanshah province

    NASA Astrophysics Data System (ADS)

    Taheri, Kamal; Taheri, Milad; Parise, Mario

    2015-04-01

    Bare and covered karst areas, with developed karstic aquifers, cover 35 percent of the Kermanshah province in western Iran. These aquifers are the vital sources for drinking and agricultural water supplies. Over the past decade, intensive groundwater use (exploitation) for irrigation imposed a significant impact on the carbonate environments. The huge amount of groundwater over-exploitations has been carried out and still goes on by local farmers in the absence of appropriate governance monitoring control. Increasing in water demands, for more intense crop production, is an important driving force toward groundwater depletion in alluvial aquifers. Progressive groundwater over-exploitations from underlying carbonate rocks have led to dramatic drawdown in alluvial aquifers and deep karst water tables. Detecting new sources of groundwater extractions and prohibiting the karst water utilization for agricultural use could be the most effective strategy to manage the sustainability of covered karst aquifers. Anthropogenic pressures on covered karst aquifers have magnified the drought impacts and caused dryness of most of the karst springs and deep wells. In this study, the combination of geophysical and geological studies was used to estimate the most intensively exploited agricultural zones of Islam Abad plain in the southwestern Kermanshah province using GIS. The results show that in the past decade a great number of deep wells were drilled through the overburden alluvial aquifer and reached the deep karst water resources. However, the difficulties involved in monitoring deep wells in covered karst aquifer were the main cause of karst water depletion. Overexploitation from both alluvial and karst aquifers is the main reason for drying out the Arkawazi, Sharafshah, Gawrawani karst springs, and the karst drinking water wells 1, 3 and 5 of Islam Abad city. Karst spring landscape destructions, fresh water supply deficit for inhabitants, decreasing of tourism and

  4. Recharge and sustainability of a coastal aquifer in northern Albania

    NASA Astrophysics Data System (ADS)

    Kumanova, X.; Marku, S.; Fröjdö, S.; Jacks, G.

    2014-06-01

    The River Mati in Albania has formed a coastal plain with Holocene and Pleistocene sediments. The outer portion of the plain is clay, with three underlying aquifers that are connected to an alluvial fan at the entry of the river into the plain. The aquifers supply water for 240,000 people. Close to the sea the aquifers are brackish. The brackish water is often artesian and found to be thousands of years old. Furthermore, the salinity, supported by δ18O results, does not seem to be due to mixing with old seawater but due to diffusion from intercalated clay layers. Heavy metals from mines in the upstream section of River Mati are not an immediate threat, as the pH buffering of the river water is good. Moreover, the heavy metals are predominantly found in suspended and colloidal phases. Two sulphur isotope signatures, one mirroring seawater sulphate in the brackish groundwater (δ34S >21 ‰) and one showing the influence of sulphide in the river and the fresh groundwater (δ34S <10 ‰), indicate that the groundwater in the largest well field is recharged from the river. The most serious threat is gravel extraction in the alluvial fan, decreasing the hydraulic head necessary for recharge and causing clogging of sediments.

  5. Hydrogeologic framework of the Boise Aquifer system, southwestern Idaho

    SciTech Connect

    Squires, E.; Wood, S.H. ); Osiensky, J.L. )

    1993-04-01

    The City of Boise relies upon the underlying groundwater resource (38,000 acre-feet/year) for 90% of its public water-supply. Basin-fill sediments which comprise this system of aquifers are divisible into five distinct hydrogeologic settings which differ on the basis of sediment type, geophysical log character, and hydraulic properties. A large buried alluvial-fan/fan-delta complex (the Boise Fan) occupies the eastern head of the basin. Down-valley gradations in sediment type show a general increase in unit thickness and sediment color more typically gray; reflecting transition to the lake environment of deposition. Basinward (northwestward), the ancient fan materials grade into lake/fan transitional sediments which grade to predominantly lake sediment which grade to gray mudstones and fine sand layers of the deep lake environment. The depth to which drinking-water aquifers extend is limited by an underlying sequence of relatively impermeable volcanic rocks. Specific capacities of efficient wells, 400--1,200 feet deep and open to 80--100 feet of sand are highest in the lake/fan transition and the lacustrine aquifers of central Boise, lowest for the Boise Fan and intermediate for the deep artesian sand aquifers of west Boise. As a result of screen and filter-pack design based upon attention to sampling drill cuttings, sieve analysis of sands, and geophysical log location of aquifers, efficiency and productivity of new wells has been greatly increased. Groundwater recharge to the deeper aquifers is via permeable surface gravels. Increased groundwater withdrawals have possibly accelerated recharge by increasing vertical hydraulic gradients. Overbored wells with continuous surface-to-depth gravel packs, wells open to multiple aquifers, and improperly abandoned wells with deteriorating casing are also conduits for polluted shallow groundwater to enter the deeper aquifers.

  6. Regional Groundwater Flow in the Louisville Aquifer.

    PubMed

    Tiaif, Syafrin; Serrano, Sergio E

    2015-01-01

    The unconfined alluvial aquifer at Louisville, Kentucky, is an important source of water for domestic and industrial uses. It has been the object of several modeling studies in the past, particularly via the application of classical analytical solutions, and numerical solutions (finite differences and finite elements). A new modeling procedure of the Louisville aquifer is presented based on a modification of Adomian's Decomposition Method (ADM) to handle irregularly shaped boundaries. The new approach offers the simplicity, stability, and spatial continuity of analytical solutions, in addition to the ability to handle irregular boundaries typical of numerical solutions. It reduces to the application of a simple set of algebraic equations to various segments of the aquifer. The calculated head contours appear in reasonably agreement with those of previous studies, as well as with those from measured head values from the U.S. Geological Survey field measurement program. A statistical comparison of the error standard deviation is within the same range as that reported in previous studies that used complex numerical solutions. The present methodology could be easily implemented in other aquifers when preliminary results are needed, or when scarce hydrogeologic information is available. Advantages include a simple approach for preliminary groundwater modeling; an analytic description of hydraulic heads, gradients, fluxes, and flow rates; state variables are described continuously over the spatial domain; complications from stability and numerical roundoff are minimized; there is no need for a numerical grid or the handling of large sparse matrices; there is no need to use specialized groundwater software, because all calculations may be done with standard mathematics or spreadsheet programs. Nonlinearity, the effect of higher order terms, and transient simulations could be included if desired.

  7. Nitrate in aquifers beneath agricultural systems

    USGS Publications Warehouse

    Burkart, M.R.; Stoner, J.D.; ,

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  8. Nitrate in aquifers beneath agricultural systems

    USGS Publications Warehouse

    Burkart, M.R.; Stoner, J.D.

    2002-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of

  9. Nitrate in aquifers beneath agricultural systems.

    PubMed

    Burkart, M R; Stoner, J D

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  10. Nitrate in aquifers beneath agricultural systems.

    PubMed

    Burkart, M R; Stoner, J D

    2002-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.

  11. Downstream hydraulic geometry of alluvial rivers

    NASA Astrophysics Data System (ADS)

    Julien, P. Y.

    2015-03-01

    This article presents a three-level approach to the analysis of downstream hydraulic geometry. First, empirical concepts based on field observations of "poised" conditions in irrigation canals are examined. Second, theoretical developments have been made possible by combining basic relationships for the description of flow and sediment transport in alluvial rivers. Third, a relatively new concept of equivalent channel widths is presented. The assumption of equilibrium may describe a perpetual state of change and adjustments. The new concepts define the trade-offs between some hydraulic geometry parameters such as width and slope. The adjustment of river widths and slope typically follows a decreasing exponential function and recent developments indicate how the adjustment time scale can be quantified. Some examples are also presented to illustrate the new concepts presented and the realm of complex river systems.

  12. Use of spectral data and Landsat TM for mapping alluvial fan deposits of the Rosillos Mountains in Brewster County, Texas

    SciTech Connect

    Bittick, S.M.; Morgan, K.M.; Busbey, A.B. . Dept. of Geology)

    1993-02-01

    The Rosillos Mountains consist of a large, highly faulted and fracture, exposed Tertiary igneous intrusion (laccolith) located adjacent to Big Bend National Park. This study examines the alluvial deposits that fan out over the 25,000 acre privately owned Rosillos Ranch located on the east side of the laccolith. Using a field spectrometer, spectral curves were generated for the various materials present. These surface reflectance patterns were used for spectral recognition and, along with Landsat digital data, for computer classification mapping of the alluvial fans. Several computer classification techniques will be presented along with mapping accuracies. Initial results indicate the resulting Landsat generated fan deposit maps are, in fact, related to the source areas and the age of deposition.

  13. Age and quality of ground water and sources of nitrogen in the aquifers in Pumpkin Creek Valley, western Nebraska, 2000

    USGS Publications Warehouse

    Steele, G.V.; Cannia, J.C.; Sibray, S.S.; McGuire, V.L.

    2005-01-01

    Ground water is the source of drinking water for the residents of Pumpkin Creek Valley, western Nebraska. In this largely agricultural area, shallow aquifers potentially are susceptible to nitrate contamination. During the last 10 years, ground-water levels in the North Platte Natural Resources District have declined and contamination has become a major problem for the district. In 2000, the U.S. Geological Survey and the North Platte Natural Resources District began a cooperative study to determine the age and quality of the ground water and the sources of nitrogen in the aquifers in Pumpkin Creek Valley. Water samples were collected from 8 surface-water sites, 2 springs, and 88 ground-water sites during May, July, and August 2000. These samples were analyzed for physical properties, nutrients or nitrate, and hydrogen and oxygen isotopes. In addition, a subset of samples was analyzed for any combination of chlorofluorocarbons, tritium, tritium/helium, sulfur-hexafluoride, carbon-14, and nitrogen-15. The apparent age of ground water in the alluvial aquifer typically varied from about 1980 to modern, whereas ground water in the fractured Brule Formation had a median value in the 1970s. The Brule Formation typically contained ground water that ranged from the 1940s to the 1990s, but low-yield wells had apparent ages of 5,000 to 10,000 years before present. Data for oxygen-18 and deuterium indicated that lake-water samples showed the greatest effects from evaporation. Ground-water data showed no substantial evaporative effects and some ground water became isotopically heavier as the water moved downgradient. In addition, the physical and chemical ground-water data indicate that Pumpkin Creek is a gaining stream because little, if any, of its water is lost to the ground-water system. The water-quality type changed from a sodium calcium bicarbonate type near Pumpkin Creek's headwaters to a calcium sodium bicarbonate type near its mouth. Nitrate concentrations were

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Geohydrology and simulation of steady-state flow conditions in regional aquifer systems in Cretaceous and older rocks underlying Kansas, Nebraska, and parts of Arkansas, Colorado, Missouri, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    USGS Publications Warehouse

    Signor, D.C.; Helgesen, J.O.; Jorgensen, D.G.; Leonard, R.B.

    1997-01-01

    Three regional aquifers systems are the basis for describing the geohydrology of bedrock aquifers in the central United States. The Great Plains aquifer system, composed of Lower Cretaceous sandstone, generally contains brackish water (1,000 to 10,000 milligrams per liter dissolved solids); the Western Interior Plains aquifer system of lower Paleozoic rocks contains saline water and is laterally adjacent to the freshwater-bearing Ozark Plateaus aquifer system composed of rocks of the same age.

  16. Characteristics of Southern California coastal aquifer systems

    USGS Publications Warehouse

    Edwards, B.D.; Hanson, R.T.; Reichard, E.G.; Johnson, T.A.

    2009-01-01

    , litany of names for the various formations, lithofacies, and aquifer systems identified within these basins. Despite these nomenclatural problems, available data show that most basins contain similar sequences of deposits and share similar geologic histories dominated by glacio-eustatic sea-level fluctuations, and overprinted by syndepositional and postdepositional tectonic deformation. Impermeable, indurated mid-Tertiary units typically form the base of each siliciclastic groundwater basin. These units are overlain by stacked sequences of Pliocene to Holocene interbedded marine, paralic, fluvial, and alluvial sediment (weakly indurated, folded, and fractured) that commonly contain the historically named "80-foot sand," "200-foot sand," and "400-foot gravel" in the upper part of the section. An unconformity, cut during the latest Pleistocene lowstand (??18O stage 2; ca. 18 ka), forms a major sequence boundary that separates these units from the overlying Holocene fluvial sands and gravels. Unconfined aquifers occur in amalgamated coarse facies near the bounding mountains (forebay area). These units are inferred to become lithologically more complex toward the center of the basins and coast line, where interbedded permeable and low-permeability alluvial, fluvial, paralic, and marine facies contain confined aquifers (pressure area). Coastal bounding faults limit intrabasin and/or interbasin flow in parts of many basins. ?? 2009 Geological Society of America.

  17. Alluvial Bars of the Obed Wild and Scenic River, Tennessee

    USGS Publications Warehouse

    Wolfe, W.J.; Fitch, K.C.; Ladd, D.E.

    2007-01-01

    In 2004, the U.S. Geological Survey (USGS) and the National Park Service (NPS) initiated a reconnaissance study of alluvial bars along the Obed Wild and Scenic River (Obed WSR), in Cumberland and Morgan Counties, Tennessee. The study was partly driven by concern that trapping of sand by upstream impoundments might threaten rare, threatened, or endangered plant habitat by reducing the supply of sediment to the alluvial bars. The objectives of the study were to: (1) develop a preliminary understanding of the distribution, morphology, composition, stability, and vegetation structure of alluvial bars along the Obed WSR, and (2) determine whether evidence of human alteration of sediment dynamics in the Obed WSR warrants further, more detailed examination. This report presents the results of the reconnaissance study of alluvial bars along the Obed River, Clear Creek, and Daddys Creek in the Obed WSR. The report is based on: (1) field-reconnaissance visits by boat to 56 alluvial bars along selected reaches of the Obed River and Clear Creek; (2) analysis of aerial photographs, topographic and geologic maps, and other geographic data to assess the distribution of alluvial bars in the Obed WSR; (3) surveys of topography, surface particle size, vegetation structure, and ground cover on three selected alluvial bars; and (4) analysis of hydrologic records.

  18. Digital model of the unconsolidated aquifer system in the Modesto area, Stanislaus and San Joaquin Counties, California

    USGS Publications Warehouse

    Londquist, Clark J.

    1981-01-01

    A digital mathematical model of the unconsolidated alluvial aquifer system in the Modesto area, Calif., has been developed which can be used to determine the effects of increased pumping and water use of future water levels in the aquifer system. The model is divided into two units. The lower unit is confined in the western part of the study area by a confining clay bed; elsewhere in this unit the aquifer is unconfined. The upper unit represents an unconfined aquifer and lies above the clay bed or its extension. Where the clay bed is absent the upper and lower units are considered as a single aquifer. The model, as calibrated, can evaluate with reasonable accuracy the effects on water levels of changing stresses and stress patterns only within the area of primary interest for the upper unit. In other areas of the upper unit and for the lower unit, predicted changes should be looked upon as, at best, representing only general trends. (USGS)

  19. Measurements of aquifer-storage change and specific yield using gravity surveys

    USGS Publications Warehouse

    Pool, D.R.; Eychaner, J.H.

    1995-01-01

    Pinal Creek is an intermittent stream that drains a 200-square-mile alluvial basin in central Arizona. Large changes in water levels and aquifer storage occur in an alluvial aquifer near the stream in response to periodic recharge and ground-water withdrawals. Outflow components of the ground-water budget and hydraulic properties of the alluvium are well-defined by field measurements; however, data are insufficient to adequately describe recharge, aquifer-storage change, and specific-yield values. An investigation was begun to assess the utility of temporal-gravity surveys to directly measure aquifer-storage change and estimate values of specific yield.The temporal-gravity surveys measured changes in the differences in gravity between two reference stations on bedrock and six stations at wells; changes are caused by variations in aquifer storage. Specific yield was estimated by dividing storage change by water-level change. Four surveys were done between February 21, 1991, and March 31, 1993. Gravity increased as much as 158 microGal ± 1 to 6 microGal, and water levels rose as much as 58 feet. Average specific yield at wells ranged from 0.16 to 0.21, and variations in specific yield with depth correlate with lithologic variations. Results indicate that temporal-gravity surveys can be used to estimate aquifer-storage change and specific yield of water-table aquifers where significant variations in water levels occur. Direct measurement of aquifer-storage change can eliminate a major unknown from the ground-water budget of arid basins and improve residual estimates of recharge.

  20. Design of flood protection for transportation alignments on alluvial fans

    SciTech Connect

    French, R.H.

    1991-01-01

    The method of floodplain delineation on alluvial fans developed for the national flood insurance program is modified to provide estimates of peak flood flows at transportation alignments crossing an alluvial fan. The modified methodology divides the total alignment length into drainage design segments and estimates the peak flows that drainage structures would be required to convey as a function of the length of the drainage design segment, the return period of the event, and the location of the alignment on the alluvial fan. An example of the application of the methodology is provided. 16 refs., 5 figs.

  1. Use of computer programs STLK1 and STWT1 for analysis of stream-aquifer hydraulic interaction

    USGS Publications Warehouse

    DeSimone, Leslie A.; Barlow, Paul M.

    1999-01-01

    Quantifying the hydraulic interaction of aquifers and streams is important in the analysis of stream base fow, flood-wave effects, and contaminant transport between surface- and ground-water systems. This report describes the use of two computer programs, STLK1 and STWT1, to analyze the hydraulic interaction of streams with confined, leaky, and water-table aquifers during periods of stream-stage fuctuations and uniform, areal recharge. The computer programs are based on analytical solutions to the ground-water-flow equation in stream-aquifer settings and calculate ground-water levels, seepage rates across the stream-aquifer boundary, and bank storage that result from arbitrarily varying stream stage or recharge. Analysis of idealized, hypothetical stream-aquifer systems is used to show how aquifer type, aquifer boundaries, and aquifer and streambank hydraulic properties affect aquifer response to stresses. Published data from alluvial and stratifed-drift aquifers in Kentucky, Massachusetts, and Iowa are used to demonstrate application of the programs to field settings. Analytical models of these three stream-aquifer systems are developed on the basis of available hydrogeologic information. Stream-stage fluctuations and recharge are applied to the systems as hydraulic stresses. The models are calibrated by matching ground-water levels calculated with computer program STLK1 or STWT1 to measured ground-water levels. The analytical models are used to estimate hydraulic properties of the aquifer, aquitard, and streambank; to evaluate hydrologic conditions in the aquifer; and to estimate seepage rates and bank-storage volumes resulting from flood waves and recharge. Analysis of field examples demonstrates the accuracy and limitations of the analytical solutions and programs when applied to actual ground-water systems and the potential uses of the analytical methods as alternatives to numerical modeling for quantifying stream-aquifer interactions.

  2. Analysis of the Carmel Valley alluvial ground-water basin, Monterey County, California

    USGS Publications Warehouse

    Kapple, Glenn W.; Mitten, Hugh T.; Durbin, Timothy J.; Johnson, Michael J.

    1984-01-01

    A two-dimensional, finite-element, digital model was developed for the Carmel Valley alluvial ground-water basin using measured, computed, and estimated discharge and recharge data for the basin. Discharge data included evapotranspiration by phreatophytes and agricultural, municipal, and domestic pumpage. Recharge data included river leakage, tributary runoff, and pumping return flow. Recharge from subsurface boundary flow and rainfall infiltration was assumed to be insignificant. From 1974 through 1978, the annual pumping rate ranged from 5,900 to 9,100 acre-feet per year with 55 percent allotted to municipal use principally exported out of the valley, 44 percent to agricultural use, and 1 percent to domestic use. The pumpage return flow within the valley ranged from 900 to 1,500 acre-feet per year. The aquifer properties of transmissivity (about 5,900 feet squared per day) and of the storage coefficient (0.19) were estimated from an average alluvial thickness of 75 feet and from less well-defined data on specific capacity and grain-size distribution. During calibration the values estimated for hydraulic conductivity and storage coefficient for the lower valley were reduced because of the smaller grain size there. The river characteristics were based on field and laboratory analyses of hydraulic conductivity and on altitude survey data. The model is intended principally for simulation of flow conditions using monthly time steps. Time variations in transmissivity and short-term, highrecharge potential are included in the model. The years 1974 through 1978 (including "pre-" and "post-" drought) were selected because of the extreme fluctuation in water levels between the low levels measured during dry years and the above-normal water levels measured during the preceding and following wet years. Also, during this time more hydrologic information was available. Significantly, computed water levels were generally within a few feet of the measured levels, and computed

  3. Changes in organic matter biodegradatility influencing sulfate reduction in an aquifer contaminated by landfill leachate

    USGS Publications Warehouse

    Harris, Steve H.; Istok, Jonathan D.; Suflita, Joseph M.

    2006-01-01

    In situ experiments were conducted to measure sulfate reduction rates and identify rate-limiting factors in a shallow, alluvial aquifer contaminated with municipal landfill leachate. Single-well, push–pull tests conducted in a well adjacent to the landfill with >8 mM dissolved organic carbon (DOC) exhibited a sulfate reduction rate of 3.2 μmol SO4−2 (L sediment)−1 day−1, a value in close agreement with laboratory-derived estimates. Identical tests conducted in wells located 90 m downgradient where DOC levels remained high (>3 mM) showed no detectable sulfate consumption, and laboratory assays confirmed this observation. However, the rates of sulfate reduction in sediment samples obtained from this site were three times larger when they were amended with filter-sterilized groundwater from the upgradient location. The effect of various amendments on sulfate reduction rates was further examined in laboratory incubations using sediment collected from the downgradient site amended with 35S sulfate. Unamended sediments showed only weak conversion of the tracer to 35S sulfide (5 to 7 cpm/cm2), whereas the addition of Desulfovibrio cells increased 35S sulfide production to 44 cpm/cm2. However, the application of heat-killed Desulfovibrio had a similar stimulatory effect, as did a lactate amendment. Collectively, these findings indicate that the lack of measurable sulfate reduction at the downgradient site was not due to the absence of the necessary metabolic potential, the presence of lower sulfate concentration, or the quantity of electron donor, but by its biodegradability. The findings also indicate that field bioaugmentation attempts should be interpreted with caution.

  4. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system

    NASA Astrophysics Data System (ADS)

    Choung, Sungwook; Zimmerman, Lisa R.; Allen-King, Richelle M.; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-01

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc = 0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen + black carbon was the dominant CM fraction extracted from the sediments and accounted for > 60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that > 80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration < 1000 μg L- 1. These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM.

  5. Aquifer-nomenclature guidelines

    USGS Publications Warehouse

    Laney, R.L.; Davidson, C.B.

    1986-01-01

    Guidelines and recommendations for naming aquifers are presented to assist authors of geohydrological reports in the United States Geological Survey, Water Resources Division. The hierarchy of terms that is used for water- yielding rocks from largest to smallest is aquifer system, aquifer, and zone. If aquifers are named, the names should be derived from lithologic terms, rock-stratigraphic units, or geographic names. The following items are not recommended as sources of aquifer names: time-stratigraphic names, relative position, alphanumeric designations, depositional environment, depth of occurrence, acronyms, and hydrologic conditions. Confining units should not be named unless doing so clearly promotes understanding of a particular aquifer system. Sources of names for confining units are similar to those for aquifer names, i.e. lithologic terms, rock-stratigraphic units or geographic names. Examples of comparison charts and tables that are used to define the geohydrologic framework are included. Aquifers are defined in 11 hypothetical examples that characterize geohydrologic settings throughout the country. (Author 's abstract)

  6. The Shape of Trail Canyon Alluvial Fan, Death Valley

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Dohrenwend, John C.

    1993-01-01

    A modified conic equation has been fit to high-resolution digital topographic data for Trail Canyon alluvial fan in Death Valley, California. Fits were accomplished for 3 individual fan units of different age.

  7. Denitrification in a deep basalt aquifer: implications for aquifer storage and recovery.

    PubMed

    Nelson, Dennis; Melady, Jason

    2014-01-01

    Aquifer storage and recovery (ASR) can provide a means of storing water for irrigation in agricultural areas where water availability is limited. A concern, however, is that the injected water may lead to a degradation of groundwater quality. In many agricultural areas, nitrate is a limiting factor. In the Umatilla Basin in north central Oregon, shallow alluvial groundwater with elevated nitrate-nitrogen of <3 mg/L to >9 mg/L is injected into the Columbia River Basalt Group (CRBG), a transmissive confined aquifer(s) with low natural recharge rates. Once recovery of the injected water begins, however, NO3 -N in the recovered water decreases quickly to <3 mg/L (Eaton et al. 2009), suggesting that NO3 -N may not persist within the CRBG during ASR storage. In contrast to NO3 -N, other constituents in the recovered water show little variation, inconsistent with migration or simple mixing as an explanation of the NO3 -N decrease. Nitrogen isotopic ratios (δ(15) N) increase markedly, ranging from +3.5 to > +50, and correlate inversely with NO3 -N concentrations. This variation occurs in <3 weeks and recovery of <10% of the originally injected volume. TOC is low in the basalt aquifer, averaging <1.5 mg/L, but high in the injected source water, averaging >3.0 mg/L. Similar to nitrate concentrations, TOC drops in the recovered water, consistent with this component contributing to the denitrification of nitrate during storage.

  8. Correlation and dating of Quaternary alluvial-fan surfaces using scarp diffusion

    NASA Astrophysics Data System (ADS)

    Hsu, Leslie; Pelletier, Jon D.

    2004-06-01

    Great interest has recently been focused on dating and interpreting alluvial-fan surfaces. As a complement to the radiometric methods often used for surface-exposure dating, this paper illustrates a rapid method for correlating and dating fan surfaces using the cross-sectional shape of gullies incised into fan surfaces. The method applies a linear hillslope-diffusion model to invert for the diffusivity age, κt (m 2), using an elevation profile or gradient (slope) profile. Gullies near the distal end of fan surfaces are assumed to form quickly following fan entrenchment. Scarps adjacent to these gullies provide a measure of age. The method is illustrated on fan surfaces with ages of approximately 10 ka to 1.2 Ma in the arid southwestern United States. Two areas of focus are Death Valley, California, and the Ajo Mountains piedmont, Arizona. Gully-profile morphology is measured in two ways: by photometrically derived gradient (slope) profiles and by ground-surveyed elevation profiles. The κt values determined using ground-surveyed profiles are more consistent than those determined using photo-derived κt values. However, the mean κt values of both methods are comparable. The photometric method provides an efficient way to quantitatively and objectively correlate and relatively-date alluvial-fan surfaces. The κt values for each surface are determined to approximately 30-50% accuracy.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Groundwater contamination evolution in the Guadiamar and Agrio aquifers after the Aznalcóllar spill: assessment and environmental implications.

    PubMed

    Olías, Manuel; Moral, Francisco; Galván, Laura; Cerón, Juan Carlos

    2012-06-01

    In 1998, the Agrio and Guadiamar rivers underwent an enormous environmental disaster caused by the rupture of the Aznalcóllar tailings dam and the release of 6 hm(3) of pyrite sludge and acidic water. Both rivers run over recent alluvial materials which form a small-sized aquifer which is however important because underground water feeds the flow of the rivers. This work analyzes the state of groundwater 10 years after the spill. Before the dam failure, this aquifer was already contaminated in the zone nearest to the mine, to which the impact of the spill was added. Contamination levels in the alluvial aquifer of the Agrio River have decreased remarkably. However, they are still important, with acidic pH values and high concentrations of toxic elements (maximum values of 16 mg/L of Zn and 15 mg/L of Al). There are also important levels of contamination in the Guadiamar alluvial area closest to the mine, as well as in specific zones located further south. The concentration of toxic elements is mainly controlled by pH. The evolution of contaminant levels show a sharp decrease after the first years following the spill, followed by a subsequent stabilization. It is necessary to take measures for the recovery of the aquifer because, otherwise, groundwater will continue contributing contaminants into the Agrio and Guadiamar rivers.

  11. Hydrogeology and ground-water flow in the Memphis and Fort Pillow aquifers in the Memphis area, Tennessee

    USGS Publications Warehouse

    Brahana, J.V.; Broshears, R.E.

    2001-01-01

    On the basis of known hydrogeology of the Memphis and Fort Pillow aquifers in the Memphis area, a three-layer, finite-difference numerical model was constructed and calibrated as the primary tool to refine understanding of flow in the aquifers. The model was calibrated and tested for accuracy in simulating measured heads for nine periods of transient flow from 1886-1985. Testing and sensitivity analyses indicated that the model accurately simulated observed heads areally as well as through time. The study indicates that the flow system is currently dominated by the distribution of pumping in relation to the distribution of areally variable confining units. Current withdrawal of about 200 million gallons per day has altered the prepumping flow paths, and effectively captured most of the water flowing through the aquifers. Ground-water flow is controlled by the altitude and location of sources of recharge and discharge, and by the hydraulic characteristics of the hydrogeologic units. Leakage between the Fort Pillow aquifer and Memphis aquifer, and between the Memphis aquifer and the water-table aquifers (alluvium and fluvial deposits) is a major component of the hydrologic budget. The study indicates that more than 50 percent of the water withdrawn from the Memphis aquifer in 1980 is derived from vertical leakage across confining units, and the leakage from the shallow aquifer (potential source of contamination) is not uniformly distributed. Simulated leakage was concentrated along the upper reaches of the Wolf and Loosahatchie Rivers, along the upper reaches of Nonconnah Creek, and the surficial aquifer of the Mississippi River alluvial plain. These simulations are supported by the geologic and geophysical evidence suggesting relatively thin or sandy confining units in these general locations. Because water from surficial aquifers is inferior in quality and more susceptible to contamination than water in the deeper aquifers, high rates of leakage to the Memphis

  12. Recovery of energetically overexploited urban aquifers using surface water

    NASA Astrophysics Data System (ADS)

    García-Gil, Alejandro; Vázquez-Suñé, Enric; Sánchez-Navarro, José Ángel; Mateo Lázaro, Jesús

    2015-12-01

    Shallow aquifers have an important role in reducing greenhouse gases through helping manage the temperature of urban environments. Nevertheless, the uncontrolled rapid use of shallow groundwater resources to heat or cool urban environments can cause thermal pollution that will limit the long term sustainability of the resource. Therefore, there is a need for appropriate mitigation/remediation strategies capable of recovering energetically overexploited aquifers. In this work, a novel remediation strategy based on surface water recharge into aquifers is presented. To evaluate the capabilities of such measures for effective remediation, this strategy is optimized for a management problem raised in the overheated "Urban Alluvial Aquifer of Zaragoza" (Spain). The application of a transient groundwater flow and heat transport model under 512 different mitigation scenarios has enabled to quantify and discuss the magnitude of the remediation effect as a respond to injection rates of surface water, seasonal schedule of the injection and location of injection. The quantification of the relationship between these variables together with the evaluation of the amount of surface water injected per year in each scenario proposed have provided a better understanding of the system processes and an optimal management alternative. This work also makes awareness of the magnitude of the remediation procedure which is in an order of magnitude of tenths of years.

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

    USGS Publications Warehouse

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

    2014-01-01

    Examples of potential use of the model to investigate the groundwater system include (1) the effects of different recharge, (2) different interpretations of the extent or offset of long faults or fault zones, and (3) different conceptual models of the spatial variation of hydraulic properties. The model can also be used to examine the ultimate effects of groundwater withdrawals on a regional scale, to provide boundary conditions for local-scale models, and to guide data collection.

  14. Water quality in shallow alluvial aquifers, Upper Colorado River Basin, Colorado, 1997

    USGS Publications Warehouse

    Apodaca, L.E.; Bails, J.B.; Smith, C.M.

    2002-01-01

    Shallow ground water in areas of increasing urban development within the Upper Colorado River Basin was sampled for inorganic and organic constituents to characterize water-quality conditions and to identify potential anthropogenic effects resulting from development. In 1997, 25 shallow monitoring wells were installed and sampled in five areas of urban development in Eagle, Grand, Gunnison, and Summit Counties, Colorado. The results of this study indicate that the shallow ground water in the study area is suitable for most uses. Nonparametric statistical methods showed that constituents and parameters measured in the shallow wells were often significantly different between the five developing urban areas. Radon concentrations exceeded the proposed USEPA maximum contaminant level at all sites. The presence of nutrients, pesticides, and volatile organic compounds indicate anthropogenic activities are affecting the shallow ground-water quality in the study area. Nitrate as N concentrations greater than 2.0 mg/L were observed in ground water recharged between the 1980s and 1990s. Low concentrations of methylene blue active substances were detected at a few sites. Total coliform bacteria were detected at ten sites; however, E. coli was not detected. Continued monitoring is needed to assess the effects of increasing urban development on the shallow ground-water quality in the study area.

  15. The distribution and modeling of nitrate transport in the Carson Valley alluvial aquifer, Douglas County, Nevada

    USGS Publications Warehouse

    Naranjo, Ramon C.; Welborn, Toby L.; Rosen, Michael R.

    2013-01-01

    The distribution of nitrate as nitrogen (referred to herein as nitrate-N) concentrations in groundwater was determined by collecting more than 200 samples from 8 land-use categories: single family residential, multifamily residential, rural (including land use for agriculture), vacant land, commercial, industrial, utilities, and unclassified. Nitrate-N concentrations ranged from below detection (less than 0.05 milligrams per liter) to 18 milligrams per liter. The results of nitrate-N concentrations that were sampled from three wells equalled or exceeded the maximum contaminant level of 10 milligrams per liter set by the U.S. Environmental Protection Agency. Nitrate-N concentrations in sampled wells showed a positive correlation between elevated nitrate-N concentrations and the percentage of single-family land use and septic-system density. Wells sampled in other land-use categories did not have any correlation to nitrate-N concentrations. In areas with greater than 50-percent single-family land use, nitrate-N concentrations were two times greater than in areas with less than 50 percent single-family land use. Nitrate-N concentrations in groundwater near septic systems that had been used more than 20 years were more than two times greater than in areas where septic systems had been used less than 20 years. Lower nitrate-N concentrations in the areas where septic systems were less than 20 years old probably result from temporary storage of nitrogen leaching from septic systems into the unsaturated zone. In areas where septic systems are abundant, nitrate-N concentrations were predicted to 2059 by using numerical models within the Ruhenstroth and Johnson Lane subdivisions in the Carson Valley. Model results indicated that nitrate-N concentrations will continue to increase and could exceed the maximum contaminant level over extended areas inside and outside the subdivisions. Two modeling scenarios were used to simulate future transport as a result of removal of septic systems (source of nitrate-N contamination) and the termination of domestic pumping of groundwater. The models showed the largest decrease in nitrate-N concentrations when septic systems were removed and wells continued to pump. Nitrate-N concentrations probably will continue to increase in areas that are dependent on septic systems for waste disposal either under current land-use conditions in the valley or with continued growth and change in land use in the valley.

  16. DISPERSION OF GROUNDWATER AGE IN AN ALLUVIAL AQUIFER SYSTEM. (R825433)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  17. Ground-water quality in alluvial aquifers in the eastern Iowa basins, Iowa and Minnesota

    USGS Publications Warehouse

    Sadorf, Eric M.; Linhart, S. Michael

    2000-01-01

    The effects of land use on ground-water quality also were examined. There was a positive correlation between percentage of land used for soybean production and concentrations of metolachlor, metolachlor ethanesulfonic acid, and metolachlor oxanilic acid in ground-water samples.Data from this study and from previous studies in the Eastern Iowa Basins were compared statistically by well type (domestic, municipal, and monitoring wells). Well depths were significantly greater in domestic and municipal wells than in monitoring wells. pH, calcium, sulfate, chloride, and atrazine concentrations were significantly higher in municipal-well samples than in domestic-well samples. pH and sulfate concentrations were significantly higher in municipal-well samples than in monitoring-well samples. Ammonia was significantly higher in domestic-well samples than in monitoring-well samples, chloride was significantly higher in monitoring-well samples than in domestic-well samples, and fluoride was significantly higher in domestic-well samples than in municipal-well samples.

  18. Water availability and use pilot; methods development for a regional assessment of groundwater availability, southwest alluvial basins, Arizona

    USGS Publications Warehouse

    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

  19. Quality of groundwater in the Denver Basin aquifer system, Colorado, 2003-5

    USGS Publications Warehouse

    Musgrove, MaryLynn; Beck, Jennifer A.; Paschke, Suzanne; Bauch, Nancy J.; Mashburn, Shana L.

    2014-01-01

    Water-quality data were synthesized to evaluate factors that affect spatial and depth variability in water quality and to assess aquifer vulnerability to contaminants from geologic materials and those of human origin. The quality of shallow groundwater in the alluvial aquifer and shallow bedrock aquifer system has been adversely affected by development of agricultural and urban areas. Land use has altered the pattern and composition of recharge. Increased recharge from irrigation water has mobilized dissolved constituents and increased concentrations in the shallow groundwater. Concentrations of most constituents associated with poor or degraded water quality in shallow groundwater decreased with depth; many of these constituents are not geochemically conservative and are affected by geochemical reactions such as oxidation-reduction reactions. Groundwater age tracers provide additional insight into aquifer vulnerability and help determine if young groundwater of potentially poor quality has migrated to deeper parts of the bedrock aquifers used for drinking-water supply. Age-tracer results were used to group samples into categories of young, mixed, and old groundwater. Groundwater ages transitioned from mostly young in the water-table wells to mostly mixed in the shallowest bedrock aquifer, the Dawson aquifer, to mostly old in the deeper bedrock aquifers. Although the bedrock aquifers are mostly old groundwater of good water quality, several lines of evidence indicate that young, contaminant-bearing recharge has reached shallow to moderate depths in some areas of the bedrock aquifers. The Dawson aquifer is the most vulnerable of the bedrock aquifers to contamination, but results indicate that the older (deeper) bedrock aquifers are also vulnerable to groundwater contamination and that mixing with young recharge has occurred in some areas. Heavy pumping has caused water-level declines in the bedrock aquifers in some parts of the Denver Basin, which has the potential

  20. Vulnerability mapping of groundwater contamination based on 3D lithostratigraphical models of porous aquifers.

    PubMed

    Ducci, Daniela; Sellerino, Mariangela

    2013-03-01

    The aim of this paper is to apply a methodology in order to reconstruct a lithostratigraphic 3D model of an aquifer so as to define some parameters involved in the evaluation of the aquifer vulnerability to contamination of porous aquifers. The DRASTIC, SINTACS and AVI methods have been applied to an alluvial coastal aquifer of southern Italy. The stratigraphic reconstruction has been obtained by interpolating stratigraphic data from more than one borehole per 2 km. The lithostratigraphic reconstruction of a 3D model has been applied and used for three-dimensional or two-dimensional representations. In the first two methods, the layers of the vadose zone and the aquifer media have been evaluated not only by the interpolation of the single boreholes and piezometers, but also by the 3D model, assigning the scores of the parameters of each layer of the 3D model. The comparison between the maps constructed from the weighted values in each borehole and the maps deriving from the attribution of the values of each layer of the 3D model, highlights that the second representation avoids or minimizes the "bullseye" effect linked to the presence of boreholes with higher or lower values. The study has demonstrated that it is possible to integrate a 3D lithostratigraphic model of an aquifer in the assessment of the parameters involved in the evaluation of the aquifer vulnerability to contamination by Point Count System methods.

  1. Groundwater quality monitoring in shallow and deep aquifers in Saidabad tahsil area, Mathura district, India.

    PubMed

    Misra, Anil K; Mishra, Ajai

    2006-06-01

    Water availability in arid regions is both sporadic and highly variable in quantity. If the water quality shows large variations of salinity and concentration of other chemical constituents with depth and time span, it has considerable effect on the entire hydrological set up of the area. In the Saidabad tahsil area, the deep aquifers that supply water to borewells in the alluvial plain of the Mathura region, Uttar Pradesh, have higher salinity than those of the dugwells from the shallow aquifers. The excessive drilling of tubewells and high yield tubewells are resulting in deterioration of water quality of the shallow aquifers. On the contrary, the chemical constituents such as, Na(+), K (+), Cl (-), andHCO (3) (-) show higher concentration in shallow aquifers than deep aquifers. A study carried out to monitor water quality in this region reveals that the groundwater quality varies with depth and time span in shallow and deep aquifers. Factors controlling variations in salinity and concentration of chemical constituents of the water in the two types of aquifers are discussed. The relative merits of the shallow water for potability are pointed out with respect to salinity concentrations and public health.

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

    USGS Publications Warehouse

    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.

  3. Biscayne aquifer, southeast Florida

    USGS Publications Warehouse

    Klein, Howard; Hull, John E.

    1978-01-01

    Peak daily pumpage from the highly permeable, unconfined Biscayne aquifer for public water-supply systems in southeast Florida in 1975 was about 500 million gallons. Another 165 million gallons was withdrawn daily for irrigation. Recharge to the aquifer is primarily by local rainfall. Discharge is by evapotranspiration, canal drainage, coastal seepage, and pumping. Pollutants can enter the aquifer by direct infiltration from land surface or controlled canals, septic-tank and other drainfields, drainage wells, and solid-waste dumps. Most of the pollutants are concentrated in the upper 20 to 30 feet of the aquifer; public supply wells generally range in depth from about 75 to 150 feet. Dilution, dispersion, and adsorption tend to reduce the concentrations. Seasonal heavy rainfall and canal discharge accelerate ground-water circulation, thereby tending to dilute and flush upper zones of the aquifer. The ultimate fate of pollutants in the aquifer is the ocean, although some may be adsorbed by the aquifer materials en route to the ocean, and some are diverted to pumping wells. (Woodard-USGS)

  4. Hydrogeology of the Coconino Plateau and adjacent areas, Coconino and Yavapai Counties, Arizona

    USGS Publications Warehouse

    Bills, Donald J.; Flynn, Marilyn E.; Monroe, Stephen A.

    2007-01-01

    Two large, regional ground-water flow systems occur in the Coconino Plateau and adjacent areas: the C aquifer and the Redwall-Muav aquifer. The C aquifer occurs mainly in the eastern and southern parts of the 10,300-square-mile Coconino Plateau study area, and the Redwall-Muav aquifer underlies the entire study area. The C aquifer is a water-table aquifer for most of its occurrence with depths to water that range from a few hundred feet to more than 1,500 feet. In the western part of the Coconino Plateau study area, the C aquifer is dry except for small localized perched water-bearing zones decoupled from the C aquifer to the east. The Redwall-Muav aquifer underlies the C aquifer and ranges from at least 3,000 feet below land surface in the western part of the Coconino Plateau study area to more than 3,200 feet below land surface in the eastern part of the study area. The Redwall-Muav aquifer is a confined aquifer for most of its occurrence with hydraulic heads of several hundred to more than 500 feet above the top of the aquifer in the western part of the study area and more than 2,000 feet above the top of the aquifer in the eastern part of the study area near Flagstaff. In the eastern and northeast parts of the area, the C aquifer and the Redwall-Muav aquifer are in partial hydraulic connection through faults and other fractures. The water discharging from the two aquifers on the Coconino Plateau study area is generally of good quality for most intended uses. Water from sites in the lower Little Colorado River Canyon had high concentrations of most trace elements relative to other springs, rivers, and streams in the study area. Concentrations of barium, arsenic, uranium, and lead, and gross alpha radioactivity were greater than U.S. Environmental Protection Agency Maximum Contaminant Levels for drinking water at some sites. Ground water discharging to most springs, streams, and wells on the Coconino Plateau and in adjacent areas is a calcium magnesium

  5. Alluvial Fans on Titan Reveal Atmosphere and Surface Interactions and Material Transport

    NASA Astrophysics Data System (ADS)

    Radebaugh, J.; Ventra, D.; Lorenz, R. D.; Farr, T. G.; Kirk, R. L.; Hayes, A.; Malaska, M. J.; Birch, S.; Liu, Z. Y. C.; Lunine, J. I.; Barnes, J. W.; Le Gall, A. A.; Lopes, R. M. C.; Stofan, E. R.; Wall, S. D.; Paillou, P.

    2015-12-01

    Alluvial fans, important depositional systems that record how sediment is stored and moved on planetary surfaces, are found on the surface of Titan, a body of significantly different materials and process rates than Earth. As seen by Cassini's Synthetic Aperture Radar (SAR) images at 350 m resolution, fans on Titan are found globally and are variable in size, shape and relationship to adjacent landforms. Their morphologies and SAR characteristics, which reveal roughness, textural patterns and other material properties, show similarities with fans in Death Valley seen by SAR and indicate there are regions of high relative relief locally, in the Ganesa, Xanadu and equatorial mountain belt regions. The Leilah Fluctus fans near Ganesa are ~30 km x 15 km, similar to the largest Death Valley fans, and revealing mountainous topography adjacent to plains. Others have gentle slopes over hundreds of kilometers, as in the high southern latitude lakes regions or the Mezzoramia southern midlatitudes, where a fan system is 200 km x 150 km, similar to the Qarn Alam fan emerging into the Rub al Khali in Oman. Additionally, there is evidence for a range of particle sizes, from relatively coarse (~2 cm or more) to fine, revealing long-term duration and variability in erosion by methane rainfall and transport. Some features have morphologies consistent with proximality to high-relief source areas and highly ephemeral runoff, while others appear to draw larger catchment areas and are perhaps characterized by more prolonged episodes of flow. The presence of many fans indicates the longevity of rainfall and erosion in Titan's surface processes and reveals that sediment transport and the precipitation that drives it are strongly episodic. Alluvial fans join rivers, lakes, eroded mountains, sand dunes and dissolution features in the list of surface morphologies derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between the two planetary

  6. Groundwater Remediation in a Floodplain Aquifer at Shiprock, New Mexico

    SciTech Connect

    Peterson, Dave; Miller, David; Kautsky, Mark; Dander, David; Nofchissey, Joni

    2016-03-06

    A uranium- and vanadium-ore-processing mill operated from 1954 to 1968 within the Navajo Nation near Shiprock, New Mexico. By September 1986, all tailings and structures on the former mill property were encapsulated in a disposal cell built on top of two existing tailings piles on the Shiprock site (the site) [1]. Local groundwater was contaminated by multiple inorganic constituents as a result of the milling operations. The U.S. Department of Energy (DOE) took over management of the site in 1978 as part of the Uranium Mill Tailings Remedial Action (UMTRA) Project. The DOE Office of Legacy Management currently manages ongoing activities at the former mill facility, including groundwater remediation. Remediation activities are designed primarily to reduce the concentrations and total plume mass of the mill-related contaminants sulfate, uranium, and nitrate. In addition to contaminating groundwater in alluvial and bedrock sediments directly below the mill site, ore processing led to contamination of a nearby floodplain bordering the San Juan River. Groundwater in a shallow alluvial aquifer beneath the floodplain is strongly influenced by the morphology of the river channel as well as changing flows in the river, which provides drainage for regional runoff from the San Juan Mountains of Colorado. As part of a recent study of the floodplain hydrology, a revised conceptual model was developed for the alluvial aquifer along with an updated status of contaminant plumes that have been impacted by more than 10 years of groundwater pumping for site remediation purposes. Several findings from the recent study will be discussed here.

  7. Characteristics of bedrock-alluvial anastomosed rivers: the Mekong River in Cambodia

    NASA Astrophysics Data System (ADS)

    Meshkova, Liubov. V.; Carling, Paul. A.

    2010-05-01

    intensity and channel sinuosity. In addition, luminescence dating of the sediments from a palaeochannel and the sediments constituting the surfaces of alluvial islands and an adjacent plain elucidate paleo-the development of the Mekong in this region. Finally, the description of the channel planform and the network metrics provide a quantitative means to describe the distinctive character of the Mekong in comparison with other well known large alluvial anastomosed river systems in similar environmental settings.

  8. The provenance of Borneo's enigmatic alluvial diamonds

    NASA Astrophysics Data System (ADS)

    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).

  9. Numerical modelling of groundwater flow to understand the impacts of pumping on arsenic migration in the aquifer of North Bengal Plain

    NASA Astrophysics Data System (ADS)

    Sikdar, P. K.; Chakraborty, Surajit

    2017-03-01

    In this paper, numerical simulations of regional-scale groundwater flow of North Bengal Plain have been carried out with special emphasis on the arsenic (As)-rich alluvium filled gap between the Rajmahal hills on the west and the Garo hills on the east. The proposed concern of this modelling arose from development that has led to large water table declines in the urban area of English Bazar block, Malda district, West Bengal and possible transport of As in the near future from the adjacent As-polluted aquifer. Groundwater occurs under unconfined condition in a thick zone of saturation within the Quaternary alluvial sediments. Modelling indicates that current pumping has significantly changed the groundwater flowpaths from pre-development condition. At the present pumping rate, the pumping wells of the urban area may remain uncontaminated till the next 25 yrs, considering only pure advection of water but some water from the As-polluted zone may enter wells by 50 yrs. But geochemical and other processes such as adsorption, precipitation, redox reaction and microbial activity may significantly retard the predicted rate by advective transport. In the rural areas, majority of the water pumped from the aquifer is for irrigation, which is continuously re-applied on the surface. The near-vertical nature of the flowpaths indicates that, where As is present or released at shallow depths, it will continue to occur in pumping wells. Modelling also indicates that placing all the pumping wells at depths below 100 m may not provide As-free water permanently.

  10. Impact of the alluvial style on the geoarcheology of stream valleys

    NASA Astrophysics Data System (ADS)

    Guccione, Margaret J.

    2008-10-01

    depositional environments. Many sites along the active meander belt of the Red River were likely lost due to high rates of channel migration. Nevertheless, intense occupation of Paleo-Indian through Caddoan groups assures that many significant sites have been preserved. The wide valley and high rates of sedimentation suggest that many sites are likely buried, particularly along natural levees flanking an older meander belt. Recorded sites are also present along streams that incise the terrace, along the terrace margin, and along small channels that cross the backswamp. The spatial and temporal site distribution along the lower Mississippi valley is distinct in comparison with the Red River because the Mississippi valley is wider, the terraces are younger and less dissected, and the floodplain has more relief and is not broadly inundated by floodwater with relatively low sediment concentrations. Most of the significant Archaic through Mississippian period floodplain sites are located along the surfaces of abandoned Mississippi and distributary meander belts which aggraded above the adjacent backswamp and have rarely been influenced by flood sedimentation since abandonment. Abundant Paleo-Indian through Mississippian period sites are also widely distributed across undissected terraces. Only a few significant Mississippian sites are present along the active meander belt and in the backswamp where flooding was common. In comparison with the Red River, the archaeological record of the floodplain is less likely to be influenced by burial or erosion due to the Mississippi River having lower rates of overbank sedimentation and channel migration, respectively. The variable alluvial styles of the lower Missouri River, lower Red River, and the lower Mississippi River valleys presented varying opportunities and constraints to occupation and sustained settlement, and resulted in widely varying archaeological patterns that are partly dependent upon the alluvial geomorphology.

  11. Investigating groundwater flow between Edwards and Trinity aquifers in central Texas.

    PubMed

    Wong, C I; Kromann, J S; Hunt, B B; Smith, B A; Banner, J L

    2014-01-01

    Understanding the nature of communication between aquifers can be challenging when using traditional physical and geochemical groundwater sampling approaches. This study uses two multiport wells completed within Edwards and Trinity aquifers in central Texas to determine the degree of groundwater inter-flow between adjacent aquifers. Potentiometric surfaces, hydraulic conductivities, and groundwater major ion concentrations and Sr isotope values were measured from multiple zones within three hydrostratigraphic units (Edwards and Upper and Middle Trinity aquifers). Physical and geochemical data from the multiport wells were combined with historical measurements of groundwater levels and geochemical compositions from the region to characterize groundwater flow and identify controls on the geochemical compositions of the Edwards and Trinity aquifers. Our results suggest that vertical groundwater flow between Edwards and Middle Trinity aquifers is likely limited by low permeability, evaporite-rich units within the Upper and Middle Trinity. Potentiometric surface levels in both aquifers vary with changes in wet vs. dry conditions, indicating that recharge to both aquifers occurs through distinct recharge areas. Geochemical compositions in the Edwards, Upper, and Middle Trinity aquifers are distinct and likely reflect groundwater interaction with different lithologies (e.g., carbonates, evaporites, and siliceous sediments) as opposed to mixing of groundwater between the aquifers. These results have implications for the management of these aquifers as they indicate that, under current conditions, pumping of either aquifer will likely not induce vertical cross-formational flow between the aquifers. Inter-flow between the Trinity and the Edwards aquifers, however, should be reevaluated as pumping patterns and hydrogeologic conditions change.

  12. Identifying aquifer type in fractured rock aquifers using harmonic analysis.

    PubMed

    Rahi, Khayyun A; Halihan, Todd

    2013-01-01

    Determining aquifer type, unconfined, semi-confined, or confined, by drilling or performing pumping tests has inherent problems (i.e., cost and complex field issues) while sometimes yielding inconclusive results. An improved method to cost-effectively determine aquifer type would be beneficial for hydraulic mapping of complex aquifer systems like fractured rock aquifers. Earth tides are known to influence water levels in wells penetrating confined aquifers or unconfined thick, low-porosity <