bluuebunny/crossref_metadata_2025_split huggingface dataset:
VECTOR ‐ A Computer Program That Utilizes SURFER or GRAPHER to Plot a Vector Field
Authors: Lu Ning , Amter Steven 
Published: August 2005

AbstractVECTOR is a Fortran 77 program that enables SURFER or GRAPHER to rapidly convert a two‐dimensional field of vectors into graphical form. SURFER and GRAPHER are both DOS format commercial graphics packages. The resulting graphical output can be plotted on‐screen or as hardcopy. Vector arrows and the size of the plot can be either manually or automatically scaled. For input, VECTOR requires only four pieces of data for each point: the x and y coordinates of the point and the x and y components of the vector's magnitude. VECTOR is an interactive program with defaults and on‐screen menus to simplify use.
Modeling Regional Ground‐Water Flow in Fulton County, Indiana: Using the Analytic Element Method
Authors: Haitjema Henk M. 
Published: August 2005

AbstractIn 1989, the Four County Landfill (FCL) in Fulton County, Indiana was closed by a federal judge because of regulatory violations and its threat to the environment. As part of the litigation, a ground‐water flow modeling study was performed on behalf of a group of concerned citizens. Time constraints and, even more importantly, budgetary constraints called for an approach which could be implemented quickly and would yield meaningful results without additional field data acquisition. The modeling was performed with the relatively new analytic element method.The new method employs superposition of closed form analytic solutions, rather than a grid or element network, and proved an effective tool in answering some unresolved hydrogeological questions. The study results demonstrate substantially higher regional and local hydraulic conductivities than suggested by the landfill consultants, well‐connected upper and lower aquifer zones at the site, and potential ground‐water travel times from the landfill to the nearby Tippecanoe River of less than 15 years.
The Use and Performance of Collector Wells Within the Regolith Aquifer of Sri Lanka
Authors: Ball D. F. , Herbert R. 
Published: August 2005

AbstractThirty‐two collector wells were constructed from existing large‐diameter wells dug in weathered hard rock (regolith) areas of the northern Dry Zone of Sri Lanka. A collector well is constructed by drilling 30 m long horizontal adits from the base of the dug well so as to exploit the permeable layer of the regolith, which lies just above the zone of slightly weathered rock. Across the North‐Central Province of the island, the water table commonly lies within the regolith for most of the year enabling dug wells to yield water. The generally poor yield of these wells and the occasional dry well has resulted in this aquifer being largely neglected by developers with most recent efforts going into the construction of many slim boreholes.The objectives of this work were: (1) to enhance the yields from suitable dug wells, (2) to observe the variation in yield improvement for wells with different constructions and in varying geologic and hydrogeologic environments, and (3) to monitor the performance of the converted wells throughout the dry season.The project has demonstrated that, on average, the conversion of a dug well to a collector well more than doubles the yield of ground water and that these yields are sustainable throughout the dry season. Safe yields from these wells average an equivalent continuous yield of 60 m3/day, assuming a 100 day dry period.
Effects of Waste‐Water Irrigation on Aqueous Geochemistry Near Paris, Texas
Authors: Tedaldi Dante J. , Loehr Raymond C. 
Published: August 2005

AbstractA comprehensive assessment of the environmental impact of a full‐scale, operating overland flow (OLF) land treatment system was made at the Campbell Soup (Texas), Inc. facility in Paris, Texas. The system treats over 16,000 m3/d of waste water and has been in operation for over 25 years. Field samples of soil, waste water, OLF runoff, and ground water collected during the study and detailed long‐term process records maintained by Campbell Soup were used as part of the evaluation. Geochemical data indicated that sulfate‐chloride facies were dominant for the ground water collected at the OLF site. Field data and calculations indicated that the evapotranspirative concentration of salts in the applied waste water would be insufficient to produce the measured concentrations in the ground water. A pattern of increasing ionic concentration over time (1968 to 1989) with small changes in ionic ratios suggested a trend toward the dissolution and concentration of naturally present minerals (such as gypsum and sodium chloride) in the slow moving ground water. Predictions made with the aid of MINTEQA2, a thermodynamic equilibrium model, indicated that precipitation of carbonates and simultaneous ion exchange on clays could represent a significant mechanism for the removal of calcium and magnesium from solution and the addition of sodium. The development of a slightly saline, semiconfined aquifer was strongly suggested by the ground‐water geochemical data, soil data, the estimated rate of infiltration, field hydraulic conductivity, MINTEQA2 model predictions and the magnitude of the volume of waste water applied.
Effects of Nutrient Management on Nitrate Levels in Ground Water Near Ephrata, Pennsylvania
Authors: Hall David W. 
Published: August 2005

AbstractEffects of the implementation of nutrient management practices on ground‐water quality were studied at a 55‐acre farm in Lancaster County, Pennsylvania, from 1985‐90. After nutrient management practices were implemented at the site in October 1986, statistically significant decreases (Wilcoxon Mann‐Whitney test) in median nitrate concentrations in ground‐ water samples occurred at four of the five wells monitored. The largest decreases in nitrate concentration occurred in samples collected at the wells that had the largest nitrate concentrations prior to nutrient management. The decreases in median nitrate concentrations in ground‐water samples ranged from 8 to 32 percent of the median concentrations prior to nutrient management and corresponded to nitrogen application decreases of 39 to 67 percent in contributing areas that were defined upgradient of these wells.Changes in nitrogen applications to the contributing areas of five water wells were correlated (Spearman rank‐sum test) with nitrate concentrations of the well water. Changes in ground‐water nitrate concentrations lagged behind the changes in applied‐nitrogen fertilizers (primarily manure) by approximately 4 to 19 months.
Pathline and Geochemical Evolution of Ground Water in a Regional Discharge Area, Red River Valley, North Dakota
Authors: Gerla Philip J. 
Published: August 2005

AbstractGround water in the Red River Valley region of North Dakota evolves from HCO3 to SO4 to Cl‐type water over a distance of less than 100 km. Pathline analysis of ground‐water flow in a transect across the valley combined with chemical equilibrium and mass balance relationships explain the processes responsible for the observed geochemical evolution. Prior geological studies have shown that the central Red River Valley is a discharge zone for regional ground‐water flow. Discharged waters are generated from different sources, processes, and pathlines. Closed surface drainage and small permeability provide Na‐HCO3 water for bedrock recharge on the western side of the transect. In contrast, greater recharge in shale outwash is characterized by Ca‐Mg‐HCO3 water. Both ultimately evolve to SO4 water with similar proportions of major cations. Upward flow through Paleozoic sediments into the Lower Cretaceous Inyan Kara Group consists of Na‐Cl water modified by downward leakage of SO4 water from Cretaceous shale and HCO3‐SO4 water from glacial sediments. Discharged ground water reveals chemical characteristics that suggest mixing of spatially varying proportions of local recharge and more evolved, deeper ground water. Mineral/ground‐water equilibria and estimation of mass transfer indicate that ground‐water composition is largely controlled by carbonate precipitation and dissolution, gypsum dissolution, and clay cation exchange.
An Evaluation of Flow Net Analysis for Aquifer Identification
Authors: Scott David M. 
Published: August 2005

AbstractA computer‐assisted flow net analysis technique was developed and evaluated using a hypothetical heterogeneous aquifer with spatially variable recharge. Flow nets were derived and analyzed for cases with differing piezometric observation density and accuracy. Using a criterion to determine a best approximation to the observed piezometric surface, the transmissivity distributions implied by fitted surfaces were compared with the known true transmissivities. Where an optimum approximation to the piezometric surface was clearly defined, the resulting computed transmissivities compared favorably with the known values. With sparse or inaccurate observations, it became increasingly difficult to identify an optimum solution. The experiments illustrate some of the difficulties inherent in the ground‐water inverse problem and the flow net analysis method. Application of the method to real field cases has yet to be tested.
Prediction of Flow and Hydraulic Head Fields for Vertical Circulation Wells
Authors: Philip Ross D. , Walter Gary R. 
Published: August 2005

AbstractA vertical circulation well is a well completed in two intervals with extraction induced in one interval and injection induced in the other, generating a circulating flow field near the well. A vertical circulation well may be used to remediate contaminated ground water by air stripping the extracted water and then reinjecting the clean water; by introducing oxygen and/or nutrients to the extracted water before reinjecting it, thereby stimulating the natural bioremediation of the water; or by injecting appropriate chemicals or microbes, effecting remediation of the circulated water. This paper summarizes an analytical technique for predicting the steady‐state hydraulic head and flow fields caused by the operation of multiple vertical circulation wells in a confined aquifer with a regional gradient. The method begins with the hydraulic head solution for a point sink in an infinite aquifer. The point sink is then integrated to derive the solution for a line sink. Linear superposition is applied to obtain the hydraulic head resulting from multiple line sinks and sources in a homogeneous confined aquifer. This solution is then differentiated to obtain the hydraulic head gradient and three‐dimensional velocity field. The velocity field is numerically integrated by an adaptive Runge‐Kutta scheme to obtain the pathlines of three‐dimensional flow.
Influence of Environmental Factors on Denitrification in Sediment Contaminated with JP‐4 Jet Fuel
Authors: Bradley Paul M. , Marjorie Aelion C. , Vroblesky Don A. 
Published: August 2005

AbstractIn 1975, the loss of approximately 83,000 gallons of JP‐4 grade jet fuel resulted in contamination of the shallow aquifer near North Charleston, South Carolina. To identify those factors likely to influence microbial activity under denitrifying conditions, we examined the fate of amended NO3, the effect of pH, NO3, and PO4 on denitrification, and the variability of denitrification in sediments collected at the site. Denitrification (N2O‐N production) accounted for 98% of the depletion of NO3‐N under anaerobic conditions. Both carbon mineralization and denitrification rates increased asymptotically with increasing NO3 to a maximum at approximately 1 mM NO3. Addition of up to 1 mM PO4 did not significantly increase N2O and CO2 production. Denitrification rates were at least 38% lower at pH = 4 than observed at pH = 7. Comparison of samples with differing degrees of hydrocarbon contamination indicated that at least a tenfold variation in sediment denitrification occurs at the North Charleston site.
Common Sense in Ground‐Water Protection and Management in the United States
Authors: LeGrand Harry E. , Rosen Lars 
Published: August 2005

AbstractInterests in the development and protection of ground water have had unbalanced thrusts through the years, focusing on special types of problems that arise at a particular time. Massive funding and excessively rigid rules guided by bureaucratic procedures have resulted in excessive effort in some activities and neglect in others.Of special importance are the needs for optimal use of existing experience and data and for strengthening the hydrogeologic experience at policy and regulatory levels. At hand are (1) great piles of hydrogeologic data, some unneeded, (2) widely varying background knowledge and varying experience of workers, and (3) types and ranges of uncertainties. To make optimal use of available data and knowledge, to handle uncertainties, and to properly integrate the hydrogeologic conditions with other factors, there should be risk‐based approaches in a decision analysis framework. Better balanced efforts toward future ground‐water protection and management can be realized by incorporating features of the suggested framework approach.
Optimal Orientation of Water‐Supply Boreholes in Fractured Aquifers
Authors: Banks David 
Published: August 2005

AbstractThe chance of encountering a water‐bearing fracture when boring in a hard‐rock aquifer can be maximized by drilling a borehole at an optimal inclination from the vertical, and an optimal azimuth with respect to fracture orientation. This paper describes the process of calculating the optimal borehole orientation for two common fracture patterns (orthogonal and biaxial stress‐induced), and discusses the application of the technique to a general case. It is found that, in terrains with well‐developed, transmissive vertical fracture planes, significant advantages can be obtained by drilling at large angles to the vertical.
Analytical Estimation of Ground‐Water Flow Around Cutoff Walls and Into Interceptor Trenches
Authors: Ilyinsky N. B. , Kacimov A. R. 
Published: August 2005

AbstractAn impermeable boundary of the grout cutoff has been found that maximizes the seepage flow for a specified grouting volume. The shape of a trench has been defined that maximizes the quantity of fluid entering the ground‐water flow from the trench. The seepage characteristics of the grout cutoff and the trench which have arbitrary shapes are estimated in terms of the derived exact analytical solutions of variational problems.
Combined Mathematical Model of Flow in an Aquifer‐Horizontal Well System
Authors: Tarshish Michael 
Published: August 2005

AbstractA mathematical model and calculation method were developed in this study for steady‐state flow in an aquifer‐horizontal well system under a water reservoir without the usual assumption about interface conditions that the specific discharge in the radial direction to the screen is constant along its axis.A horizontal well (i.e. drain, gallery, or lateral) is represented as a linear sink with nonuniform intensity for description of a flow in an aquifer. Flow in the screen channels is described by taking into account energy losses and the momentum flux change along the well screen's axial orifice. Substantial errors are avoided by the use of the proposed model.The mathematical model also can be used for the analysis of vertical wells.
Spreadsheet Modeling of Electrical Sounding Experiments
Authors: Sheriff Steven D. 
Published: August 2005

AbstractElectrical resistivity sounding is useful for solving a variety of ground‐water problems. To model apparent resistivities for a specific model requires one to evaluate a convolution integral. This calculation, using linear filtering, is rapid and convenient with a commercial spreadsheet. In comparison to traditional programming languages, the high‐level language and built‐in screen graphics provided by the spreadsheet save much programming time.
Inverse Analytical Techniques Applied to Coincident Contaminant Distributions at Otis Air Force Base, Massachusetts
Authors: Ala Natalyn K. , Domenico Patrick A. 
Published: August 2005

AbstractInverse analytical techniques have been applied to six coincident plumes at Otis Air Force Base near Cape Cod, Massachusetts. The plumes contain chloride, boron, trichloroethene, tetrachloroethene, and biodegradable and nonbiodegradable detergents. Thus, a host of processes including physical, chemical, and biological, are presumed to be operative. The analytical technique is structured to solve several equations simultaneously and provides unique values for several unknowns which control the behavior of the contaminant plumes. The determined parameters include source strength and size, the advective position of the contaminant front for both retarded and unretarded constituents, dispersivities in x and y, and a reaction rate constant that describes decay, biodégradation, or chemical transformation. The obtained values for the transport parameters for the different constituents were reasonably similar, with the transverse dispersivity ranging from 1.2 to 2.7 m and the longitudinal dispersivity ranging from 6.1 to 7 m. The unretarded advective velocity of boron, chloride, and tetrachloroethene were quite similar (73, 78, and 65 m/yr) whereas tetrachloroethene had a velocity of 48 m/yr. Of special interest is the half‐life determination of the reactive constituents. The organic compounds trichloroethene and tetrachloroethene have half‐lives of 11 and 10 years, respectively, whereas the biodegradable detergent with linear alkyl sulfonate had a half‐life of 7.6 years. In all cases, this set of parameters captures the essence of the various plumes with a high degree of accuracy.
Exploration and Development of Ground Water from the Stone Forest Karst Aquifers of South China
Authors: Huntoon Peter W. 
Published: August 2005

AbstractStone forest aquifers are the most widely exploited sources for ground water in the vast south China karst belt. These aquifers occupy a thin epikarst zone that has been infilled with clastic sediments. The aquifers are characterized by large lateral permeabilities and small reservoir capacities owing to their thinness. The carbonate rocks which comprise the framework for the aquifers are usually buried under the karst plains and large karst depressions where development is desired.The stone forest aquifer exploration procedure must first locate saturated zones. Second, those parts of the saturated zone having the greatest dissolution porosity must be identified because the infilled dissolution voids contain the water.The best indicators of saturation include the combination of low topography and the presence of active karst features such as springs, karst windows (natural openings exposing the water table), and live surface streams. These elements are readily observed on intermediate scale (1:20,000) aerial photography.The depth and degree of carbonate dissolution porosity is a function of several geologic and hydrologic factors including carbonate rock type, carbonate purity, fracture density, specific discharge, age of the circulation system, etc. These variables cannot be measured directly because the carbonate rocks are usually buried under a thin mantle of clastic sediments. However, if it is recognized that the ground‐water system has already exploited the most favorable geology and that dissolution is an ongoing process, a simple indirect method can be used to identify the areas having the greatest porosity. The presence of karst depressions and recent sinkholes are indicative of the most intensely karstified and hydraulically active parts of the epikarst zone. Mapping of these surface features from stereo aerial photography is a simple geomorphology exercise that can be used to directly identify the most favorable well sites.Current well construction practices in the south China karst belt involve both dug and drilled wells. Dug wells are preferred in many locations owing to both cost‐effectiveness associated with cheap labor and lack of available drilling equipment. The dug wells look and function identically to karst windows and thus conform to timeless water use traditions in the region.
Fresh‐Water/Sea‐Water Relationship Within a Ground‐Water Flow System, Northeastern Coast of the Yucatan Peninsula
Authors: Moore Yolanda H. , Stoessell Ronald K. , Easley Dale H. 
Published: August 2005

AbstractGround‐water velocities within fractures and boreholes, hydraulic heads, and depth profiles of conductivity were measured along a 70 km section of the northeastern coast of the Yucatan Peninsula, Mexico. Hydraulic heads ranged from 40 to 60 cm above mean sea level between 2 and 4 km from the coast. Fluid velocities estimated from point‐dilution tests, in the dual‐porosity rock in a borehole several kilometers from the coast, were 0.021 cm/sec in the fresh‐water lens and 0.082 cm/sec near a fracture in the underlying sea‐water zone. Velocities in large fractures increased from 1 cm/sec 10 kilometers inland to 12 cm/sec near discharge points along the coast. This increase is attributed to the decrease in thickness of the fresh‐water lens.The thickness of the fresh‐water lens is approximately 40% less than the Ghyben‐Herzberg relation predicts for a static system, providing the potential to drive fresh water through fractures into the sea‐water zone below the halocline. Overall, the halocline appears to be in a steady‐state position due to the rapid flow of fresh water and brackish water towards the coast combined with rising sea water in corivectional flow.
Potentiometric and Aquifer Property Changes Above Subsiding Longwall Mine Panels, Illinois Basin Coalfield
Authors: Booth Colin J. , Spande Erik D. 
Published: August 2005

AbstractThis study examined the response of potentiometric levels and hydraulic properties to subsidence caused by a 725‐ft‐deep active longwall mine in southern Illinois. The overburden is mainly shale but includes a shallow sandstone aquifer, overlain by a shale aquitard, capped by thin drift. Pumping and packer tests indicate that subsidence fracturing increased the hydraulic conductivities of the sandstone aquifer by about an order of magnitude, and of certain horizons of the lower bedrock by several orders. The water table in the drift aquifer was unaffected by mining; however, heads in the bedrock units dropped sharply in response to subsidence, probably because tensional dilation of fractures increased storativities. The sandstone aquifer also displayed gradual potentiometric declines ahead of mining, and a rapid partial recovery afterwards. Depression of water levels and potentially higher well yields represent conflicting negative and positive aspects of the hydrologic impact of longwall mining.