bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Aquifer Behavior and Characteristics in the Singrauli Coalfield, Central India
Authors: Choubey Vishnu D. , Shankaranarayana I. 
Published: August 2005

AbstractHydrological investigations were conducted to determine the aquifer characteristics, recharge boundary location, and the amount of ground water which can be withdrawn safely in order to minimize potential ground–water contamination from open pit coal mining. Analysis of data obtained from bore holes drilled in the study area has revealed two aquifers: (1) an unconfined composed of medium–grained sandstone, and (2) confined composed of medium– to coarse–grained sandstone.A pumping test was conducted in Jayant block study area on the confined aquifer. Accordingly, the values for the transmissivity (T), storage coefficient (S), and hydraulic conductivity (k) obtained are 84.14 m2/day, 4.076 × 10‐4, and 4.2 × 102 m /day, respectively. The results of the pumping tests indicated that a recharge boundary is located at a distance of 163 m. The recharge boundary was determined to be a stream trending N–S and situated at about 200 meters from the pumping well, closely corroborating the field situation with pump test data.From these studies it is concluded that water–supply wells should be completed in the confined aquifer. The impact of surface mining of coal on the ground–water system in Singrauli Coalfield, Central India has been investigated. Surface–water and hydrogeologic analyses were conducted in Jayant block. Field studies measured the infiltration characteristics of surface‐mined land, determined surface–water runoff, and analyzed the hydrogeologic impacts of surface mining. This study provides the framework for three–dimensional analysis of such problems as the hydrogeology, risk of potential contamination, mine flooding, highwall stability, and reclaimed land surface.
Production and Carbon Isotopic Composition of Bacterial CO2 in Deep Coastal Plain Sediments of South Carolina
Authors: McMahon Peter B. , Williams Douglas F. , Morris James T. 
Published: August 2005

AbstractThe production and carbon isotopic composition of bacterial CO2 in cores of deep Coastal Plain sediments from South Carolina were measured. Rates of bacterial CO2 production in laboratory incubations ranged from 0 to 2,750 nanomoles of CO2 per gram of sediment per day. On average, C02 production was greater in downdip sediments than in updip sediments. There was no relation between CO2 production and total organic carbon content of the sediment. The carbon isotopic composition of bacterial CO2 ranged from ‐29.7 to ‐18.0 per mil and is controlled in part by the isotopic composition of the sedimentary organic matter from which the CO2 is derived. The isotopic composition of CO2 from downdip sediments was enriched in 13C by about 50/00, on average, relative to CO2 from updip sediments.Measurements of the production and carbon isotopic composition of bacterial CO2 given here provide evidence linking bacterial CO2 to dissolved inorganic carbon in Coastal Plain aquifers of South Carolina.
Deep‐Well Infiltration in the North‐Holland Dune Areaa
Authors: Roosma E. , Stakelbeek A. 
Published: August 2005

Abstract. The government's policy concerning the management of the dunes in the Netherlands on behalf of the interests of nature and environment is causing constraints for the waterworks of North‐Holland located in the dunes at the North Sea coast. The existing artificial recharge systems consist mostly of ponds and open canals in which imported pretreated surface water is infiltrated to provide a reliable drinking‐water supply in the province of North‐Holland. Because the quality of the water, which is infiltrated by canals, has a negative influence on ecological values, the extension of this system will not be possible anymore. Many experiments in the past were done to provide a substitute with as good a performance for the drinking‐water supply as the shallow infiltration systems but without negative impacts on nature. One of these alternatives is deep‐well infiltration: instead of infiltrating by canals, water will be infiltrated in semiconfined aquifers, so there will be less influence on existing ecological values. The Provincial Waterworks of North‐Holland are constructing a pilot plant with a capacity of 5 million m3/a (a = per year) to investigate its reliability and its suitability for a development as natural as possible of this region.This paper gives the history which has led to this new system of artificial recharge, an overall look at the preliminary investigations, and finally an overview of the main issues for the definite engineering.
Modeling Solute Transport in Ground Water At or Near Freezing
Authors: Zukowski Matthew D. , Tumeo Mark A. 
Published: August 2005

AbstractUnder freezing or near‐freezing conditions, temperature‐induced viscosity changes, solute immobilization, and solute exclusion can affect field‐scale solute transport in ground water. This can lead to concentration profiles significantly different from those predicted by models which do not account for these processes. A model (GWFREEZE) is presented which incorporates these processes into a two‐dimensional transport equation for saturated porous media subject to a hydraulic head field that does not vary with time.Ground‐water temperature can be expected to vary widely in some natural and artificial freezing and near‐freezing situations. Spatially varying temperature fields cause spatial variations in the fluid viscosity field, especially near 0° C, where viscosity varies faster with temperature than at higher temperatures. GWFREEZE models these phenomena with a viscosity‐dependent hydraulic conductivity that is a function of temperature. Solute exclusion is modeled by a variable exclusion coefficient (Ke) which represents the percentage of solute excluded at the freezing front. The freezing front is modeled as a planar no‐flow boundary behind which solutes are immobilized and at which solutes are excluded.
Assessment of Porous Media Heterogeneity by Inverse Plume Analysis
Authors: Poeter Eileen P. , Belcher Wayne R. 
Published: August 2005

AbstractResults from analysis of models of heterogeneous porous media indicate that inverse plume analysis has potential for use in delineating zones of differing characteristics within porous media even when the zones are not penetrated by a borehole. By analyzing the concentrations at pairs of points in a contaminant plume, the spatial distributions of apparent transverse dispersivity and source size are determined. Since dispersivity is an intrinsic property of a porous medium, spatial distributions of the apparent dispersivities obtained from inverse analysis of plumes are an indication of transitions in the character of the porous medium.Dispersivity values obtained by inverse plume analysis in heterogeneous porous media are “apparent” because the equation on which the analysis is based was developed under the assumption that the porous media is isotropic and homogeneous. In the case of heterogeneous porous media, the dispersivity value obtained at a given location by inverse plume analysis is affected by the spreading of the plume through different materials. Therefore, variations in dispersivity should be interpreted qualitatively for delineation of heterogeneity and not quantitatively as for input to numerical transport models.
A Method for Estimating Effective Porosity and Ground‐Water Velocity
Authors: Hall Stephen H. , Luttrell Stuart P. , Cronin William E. 
Published: August 2005

AbstractEstimates of ground‐water velocity, based either on Darcy's law or on the single‐well drift and pumpback tracer method, require prior knowledge of effective porosity. That is, after field data have been collected, the equation for ground‐water velocity, using either method, still contains the two unknowns, velocity and porosity. If the local hydraulic gradient is known and if a drift and pumpback tracer test is conducted at a well whose hydraulic conductivity has been determined, two independent functional relationships between velocity and porosity are established. By treating these functions as nonlinear simultaneous equations, a unique solution for the local velocity and porosity can be obtained.
Hydrogeology of Effluent Disposal Zones, Floridan Aquifer, South Florida
Authors: Haberfeld Joseph L. 
Published: August 2005

AbstractThe increasing population of south Florida is creating a need for greater waste‐water disposal capacity. The people of Florida are dependent on ground water for drinking, irrigation, and other uses. The emphasis on preservation of surface‐water quality means that many surface waters are not allowed to receive effluent from municipal or industrial sources. Since the 1940s, the highly transmissive zones of the nonpotable portion of the Floridan aquifer have served as disposal zones for oil field brine and later for industrial and municipal effluent.The Floridan aquifer of south Florida is a carbonate Cenozoic age aquifer. Transmissivities between 0.5 and 21 million gpd/ft exist in cavernous and fractured sequences in the aquifer. Confining zones that overlie the disposal intervals have transmissivities and hydraulic conductivities one to three orders of magnitude less than the injection intervals. These confining zones prevent low density municipal effluent from rising upward through the overlying saline waters.This paper provides an integration of previously published work with recent site‐specific data collected from deep injection wells drilled in the last two decades.
Multilayer Sampling in the Water‐Table Region of a Sandy Aquifer
Authors: Kaplan Edward , Banerjee Sujit , Ronen Daniel , Magaritz Mordeckai , Machlin Albert , Sosnow Michael , Koglin Eric 
Published: August 2005

AbstractDepth profiles of organic pollutants, metals, and anions were obtained using a ground‐water multilayer sampler (MLS) in a sandy unconfined aquifer contaminated by liquid fuels. The sampler incorporates dialysis membranes and is capable of obtaining vertical profiles with a resolution on the order of few centimeters. Of the eight solutes examined (metals, organics, and anions), all except sulfate exhibited microscale heterogeneities in their concentration over a vertical interval of 200 cm. Chloride, manganese, and iron showed a long linear concentration gradient versus depth which is probably the result of vertical mixing by rainfall input. Maximum concentrations of toluene, xylene, and xylidine at the water table were 17.1, 8.3, and 17.1 mg/l, respectively, decreasing with depth. For toluene and xylene the maximum concentrations found at the water table with the MLS are 40 and 4 times higher, respectively, than those detected at depths greater than 200 cm in water samples obtained with a pump.
Literature Review and Model (COMET) for Colloid/Metals Transport in Porous Media
Authors: Mills William B. , Liu Sally , Fong Fred K. 
Published: August 2005

AbstractThis paper summarizes topics related to colloid transport in subsurface media. The ultimate objective of the paper is to present a model that can be used to evaluate the significance of colloid facilitated transport on the mobility of metals. Field and laboratory studies are first reviewed to evaluate evidence that colloids are transported in subsurface media. Second, researchers active in the field are contacted to identify areas of ongoing research, and to solicit opinions concerning the level of understanding of mechanisms that control colloid migration. Third, the literature on colloid transport mechanisms is reviewed, with particular emphasis on colloid (and particle) filtration and on colloid stability as influenced by electrical repulsion and Van der Waals attraction. Fourth, a conceptual colloids‐metal transport model (COMET) is developed and incorporated into EPA's CML model, a model that simulates solute migration from a landfill in the unsaturated zone to a receptor (i.e., drinking‐water well) in the saturated zone. Among the major features of the COMET model are the capability to simulate multiple metal species either dissolved or adsorbed to mobile colloids (in conjunction with results from a geochemical equilibrium model), the capability to simulate the influence of multiple colloid types, and to adjust source concentration and duration in the presence of colloids that migrate from a source. These capabilities are embodied in equations (2) and (3) in the main text of this paper.As expected, results from the COMET simulations indicate that mobile phase metal concentrations (dissolved concentration plus concentration adsorbed to mobile colloids) increase as colloid concentrations increase, and arrival times of soluble metal species (solutes) to stationary receptors decrease. When the partition coefficients for solute‐colloid adsorption and solute‐soil matrix adsorption are the same, neither the increase in mobile phase concentration nor decrease in travel time is always significant. However, when partition coefficients for solute‐colloid adsorption are greater than partition coefficients for solute‐soil matrix adsorption, travel times to stationary receptors can dramatically decrease and total mobile phase concentrations dramatically increase.
Persistence of Selected Pesticides in Ground‐Water Samples
Authors: Cavalier T. C. , Lavy T. L. , Mattice J. D. 
Published: August 2005

AbstractThis study was conducted to determine the stability of five commonly used herbicides fortified into freshly collected ground water. No aquifer materials were present. Ground‐water samples obtained from three sites in eastern Arkansas were fortified with an aqueous mixture containing either the chloroacetamide herbicides, alachlor, metolachlor, and propanil, or the phenoxy herbicides, 2,4‐D and dichlorprop. Experiments were conducted at tempersitures comparable to Arkansas' extreme ground‐water temperatures, 15 and 22° C, and at initial concentrations of 1 and 5 μg/1. Degradation occurring for each herbicide was determined at two‐month intervals, for a period of 18 months.Results indicated that degradation did not begin immediately, but generally required a lag period of several months. Of the five herbicides studied, propanil degraded the fastest and to the greatest extent. After eight months, 44% to 69% of propanil at the lower fortification level and 85% to 99% at the higher level had degraded, The remaining four herbicides exhibited little or no degradation at the lower concentration during the first 12 months. By 18 months, however, significant degradation of each herbicide had occurred. Degradation generally occurred earlier for each herbicide at the higher fortification level. With the exception of 2,4‐D, a higher percentage of herbicide was broken down at the greater fortification level. Degradation was more extensive at the elevated storage temperature. In general, the degradation rate was faster in ground water taken from shallower depths. Zero‐order rate constants and half‐lives are presented. Half‐lives, including lag periods, ranged from 196 to 1907 days.
Laboratory Column Measurement of VOC Retardation Factors and Comparison with Field Values
Authors: Priddle M. W. , Jackson R. E. 
Published: August 2005

AbstractA laboratory column technique was developed to measure retardation factors (Rf) of volatile organic compounds (VOC) using geological material obtained from an outwash aquifer. The site is a former solvent disposal pit near Ottawa, Canada. The experimental column was designed as a closed system from introduction of the sample to the collection and analysis of effluent samples to prevent loss through volatilization of the VOCs. The retardation of the volatile compounds 1,4‐dioxane, tetrahydrofuran, diethyl ether, 1,2‐dichloroethane, chloroform, 1,1‐dichloroethene, and benzene was measured. The centers of mass of both the contaminant and conservative tracer breakthrough curves were compared to determine Rf. The measured Rf values ranged from 1.1 (1,4‐dioxane) to 14.3 (benzene) compared with values of 1.6 and 8.8 derived from contaminant plume lengths. Considering the uncertainty of the disposal history at the site, the values are of reasonable agreement in comparison.
Geochemical Evolution in the Cambrian‐Ordovician Sandstone Aquifer, Eastern Wisconsin: 1. Major Ion and Radionuclide Distribution
Authors: Weaver T. R. , Bahr J. 
Published: August 2005

AbstractGround water from wells in the Cambrian‐Ordovician sandstone aquifer of eastern Wisconsin often contains elevated concentrations of dissolved solids, chloride, and sulfate and locally approaches or exceeds the current drinking‐water standard for combined radium activity. Samples were collected from wells located along an approximate flow line in order to gain an improved understanding of the chemical evolution of ground water in this system. The concentrations of chloride, sulfate, and sodium increase where the aquifer is confined by the Maquoketa Shale, and the highest combined radium activity is also found in this area. Charge balance calculations and geochemical modeling indicate that dissolution of trace evaporite minerals and cation exchange are important mechanisms controlling major ion distribution. Isotopic equilibrium calculations and analysis of well cuttings from one well with alpha‐sensitive film indicate that the dissolved radionuclide activities are consistent with a uranium source occurring in shaly intervals of the sandstone aquifer at maximum local concentrations of 5 ppm.
Delineation of Traveltime‐Related Capture Areas of Wells Using Analytical Flow Models and Particle‐Tracking Analysis
Authors: Bair E. Scott , Springer Abraham E. , Roadcap George S. 
Published: August 2005

AbstractTraveltime‐related capture areas of wells can be estimated in Hydrogeologie settings with predominantly two‐dimensional flow regimes using image‐well theory, the principle of superposition, an appropriate well‐hydraulics; equation, and particle‐tracking analysis. These analytical methods can be used to simulate the response of an aquifer to pumping stress by incorporating site‐specific values of hydraulic properties, the effects of geologic and hydrologie boundaries, nonuniform regional hydraulic gradients, and well interferences. This is done by developing a conceptual model of the flow system, incorporating an image‐well solution (if needed), computing drawdowns at the intersections of a rectangular grid superposed over the area of interest, and subtracting computed drawdowns from regional prepumping head values assigned to the grid intersections. The resulting flow model can be calibrated by comparing predicted heads with measured heads. The calibrated head distribution then is used in a particle‐tracking analysis to determine flowpath trajectories and traveltime‐related capture areas of wells.Analytical flow models based on the Theis equation and the Hantush‐Jacob equation were constructed from conceptual flow models based on geologic, hydrologie, and pumpage data from wellfields completed in a confined/unconfined stratified‐drift aquifer and in a leaky‐confined fractured‐carbonate aquifer. Predicted head distributions from the calibrated flow models were used in a particle‐tracking analysis to compute flowpath trajectories and traveltime‐related capture areas. The results compare favorably with known flowpaths from sources of contamination proximal to each wellfield.
Acid Neutralization by Gulf Coast Sediments
Authors: Fink Linn E. , Aubert Winton G. , Bernard William J. 
Published: August 2005

AbstractThe capacity of sandstone to neutralize injected acid was determined for material from a waste disposal well in Jefferson Parish, Louisiana. Injection zone sandstone was found to neutralize approximately 1.51×10−3 grams H+ ions per gram of sand. Kinetics parameters were determined for reactions of acid with confining layer shale material. Reaction rate coefficients and activation energies of acid‐shale systems agree with values previously determined for reactions of acids with relatively pure clay minerals.
Estimation of Storativity from Recovery Data
Authors: Ballukraya P. N. , Sharma K. K. 
Published: August 2005

AbstractIn estimating aquifer parameters from pumping test data, it is often found advantageous to use recovery, rather than drawdown, measurements. An equation, derived from Cooper‐Jacob's (1946), is suggested for estimating storativity using residual drawdown measurements from an observation well.
Geochemical Evolution in the Cambrian‐Ordovician Sandstone Aquifer, Eastern Wisconsin: 2. Correlation Between Flow Paths and Ground‐Water Chemistry
Authors: Weaver T. R. , Bahr J. M. 
Published: August 2005

AbstractA finite‐difference ground‐water flow model linked to a particle‐tracking routine was used to determine ground‐water flow paths and residence times in the Cambrian‐Ordovician sandstone aquifer of eastern Wisconsin. The modeled region was a cross section along an approximate flow line that included the boundary between unconfmed and confined conditions in the aquifer. Modeling results indicate that lower conductivity units within the sandstone aquifer produce vertically stratified flow in the confined region. These simulation results help explain chemical signatures of ground water in different parts of the aquifer. Three distinct regions of the flow system are identified: the unconfmed zone where vertical mixing across the aquifer yields a homogeneous chemistry, the shallow part of the confined zone where sodium and sulfate charged water from the Maquoketa Shale mixes with water that has migrated from the unconfmed area, and the deeper region of the confined aquifer, containing older water that entered the system in the unconfmed area. Radium activities in ground water increase with distance along flow paths predicted by the simulation, consistent with a low concentration source of solid phase uranium and release of decay products to ground water by desorption and dissolution throughout the sandstone aquifer.
Determining the Mean Hydraulic Gradient of Ground Water Affected by Tidal Fluctuations
Authors: Series Michael E. 
Published: August 2005

AbstractTidal fluctuations in surface‐water bodies produce progressive pressure waves in adjacent aquifers. As these pressure waves propagate inland, ground‐water levels and hydraulic gradients continuously fluctuate, creating a situation where a single set of water‐level measurements cannot be used to accurately characterize ground‐water flow. For example, a time series of water levels measured in a confined aquifer in Atlantic City, New Jersey, showed that the hydraulic gradient ranged from. 01 to. 001 with a 22‐degree change in direction during a tidal day of approximately 25 hours. At any point where ground water tidally fluctuates, the magnitude and direction of the hydraulic gradient fluctuates about the mean or regional hydraulic gradient. The net effect of these fluctuations on ground‐water flow can be determined using the mean hydraulic gradient, which can be calculated by comparing mean ground‐ and surface‐water elevations. Filtering methods traditionally used to determine daily mean sea level can be similarly applied to ground water to determine mean levels. Method (1) uses 71 consecutive hourly water‐level observations to accurately determine the mean level. Method (2) approximates the mean level using only 25 consecutive hourly observations; however, there is a small error associated with this method. The exact magnitude of this error is usually unknown, and therefore the accuracy of the mean level is also unknown. Method (1) should be used if a higher degree of accuracy is required.