bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Aldicarb in Ground Water in Selected Areas of the Central Sand Plain of Wisconsin
Authors: Rothschild E. R. , Manser R. J. , Anderson M. P. 
Published: March 2006

ABSTRACTThe goal of this study was to provide a preliminary assessment of the occurrence and movement of the pesticide aldicarb in ground water in the Central Sand Plain of Wisconsin. Aldicarb concentrations in ground water beneath three main study fields and two subsidiary fields were monitored during the period December 1980–August 1981. A total of 67 well points, some nested, and one multilevel sampler were installed for this study. In addition, 25 private wells and seven irrigation wells were sampled.The data collected to date are limited both in space and time. However, several trends are evident: (1) highest concentrations of aldicarb were detected in shallow monitoring wells (those located immediately below the water table); (2) no aldicarb was detected in any of the deep monitoring wells (those located roughly 60 feet below the water table), although aldicarb was found in some of the irrigation wells finished at approximately the same depth; (3) aldicarb seems to be concentrated in roughly a 5‐foot layer near the water table, and (4) marked seasonal fluctuations in aldicarb concentrations occurred in several wells.
A New Method for Simultaneous Measurement of Cl−, Br−, NO3−, SCN−, and I− at Sub‐ppm Levels in Ground Water
Authors: Stetzenbach Klaus J. , Thompson Glenn M. 
Published: March 2006

ABSTRACTIon‐exchange high performance liquid chromatography coupled with ultraviolet absorption detection is shown to be a rapid and sensitive method for analysis of some common anions in water. Sensitivity of measurement is approximately 50 ppb for NO−2, NO−3, Br−, I−, and SCN− while Cl− has a detection limit in the one to ten ppm range. Chromatograms require 8 to 13 minutes to complete. Analyses are performed on either of two stationary phases (Whatman SAX 10 μm or Brownlee anion exchange) depending on the anions of interest in the analysis and their interferences.
A Quantitative Model to Predict a Safe Yield for Well Fields in Kufra and Sarir Basins, Libya
Authors: Ahmad Moid U. 
Published: March 2006

ABSTRACTThe Kufra and Sarir basins of Libya have huge ground‐water resources. Three well fields–Sarir, Kufra, and Jalo–have been constructed for irrigation purposes. The Tazerbo and West Sarir well fields are under construction. Wells in these well fields have tapped only a small portion of the total ground water available. The hydrological behavior of the Sarir well field (determined by using analytical and numerical models) indicated a leaky artesian aquifer and a significant partial penetration effect. Long and short‐term pump tests did not provide true estimates of the values of transmissivity and the coefficient of storage.A steady‐state model of the Kufra and Sarir basins indicated a minimum of 80 m3/s of underflow entering from Tibesti, Chad and Sudan. A transient model was constructed to pump a total of 120 m3/s from 14 well fields. The simulation indicated that sufficient drawdown was available to last at least 50 years.
Salt‐Water Intrusion in the Nile Delta
Authors: Kashef Abdel‐Aziz I. 
Published: March 2006

ABSTRACTEgypt is presently involved in a comprehensive program of land reclamation. Surface water has already been exhausted in meeting the urgent needs of agricultural expansion. If irrigation efficiency were increased, large amounts of surface water would be saved. However, this entails complex social, technical and political problems outside the scope of this paper. Ground‐water development has priority over increasing irrigation efficiency (which would take a longer time).This paper deals with identification of the intruded salt‐water wedge in the huge artesian Delta aquifer. The case is unique because most of this aquifer is invaded by salt water, and the major portion of its annual ground‐water recharge is derived from the direct seepage from the Nile River and the huge net of irrigation canals serving about 3 million acres (∼ 11,561 km2) of fertile land, as well as the infiltration of excess irrigation water. The annual overall ground‐water recharge to the aquifer was estimated as 6·40 km3/yr as explained later.Methods of salt‐water control and various techniques of water resources management are discussed in this paper. Because of the great variation in the depth of the aquifer, two unconventional methods for identifying the salt‐water wedge are also presented.
The Noordbergum Effect and Characterization of Aquitards at the Rio Maior Mining Project
Authors: Rodrigues José Delgado 
Published: March 2006

ABSTRACTThe planned exploitation of the Rio Maior lignite deposits will require a major dewatering program involving a thick leaky sand aquifer, and a heterogeneous and anisotropic aquitard complex. Diatomite, lignite, and clay are the main lithologies found in this aquitard complex. Characterization of the sand aquifer was accomplished by performing pumping tests with interpretations for steadystate and nonsteady‐state conditions. Aquitards were characterized by using both laboratory and field tests to determine hydraulic conductivity. Field methods were either those commonly adapted to leaky aquifers using water‐level data taken from observation wells tapping the underlying sand aquifer or those using water‐level data taken from piezometers located at the same distance from the pumping well and screened in the aquitard and in the aquifer. Field values of hydraulic conductivity are greater than laboratory values. In several piezometers the Noordbergum effect was observed during pumping tests. Redistribution of the loads originated by the pumping in the underlying sand aquifer is considered to be responsible for the reverse water‐level response in the overlying lignite‐diatomite complex. The Noordbergum effect has some influence in the application of the ratio method. On a practical basis, it seems reasonable to use the Noordbergum effect to compute drawdowns in the aquitards, and this leads to somewhat higher values for vertical hydraulic conductivities.
Pore‐Water Pressure in the Roof of an Underground Coal Mine in Illinois
Authors: Cartwright Keros , Hunt Cathy S. , Brower Ross D. , Nelson W. John 
Published: March 2006

ABSTRACTMost underground coal mines in Illinois are relatively dry despite their location in saturated rock lying hundreds of meters below the water table. This is probably due to the low permeabilities of the rock units associated with the coal seams. Little is known about how mines affect the groundwater system, so it is difficult to predict where a mine is likely to encounter an influx of ground water.To obtain information on the hydrogeological character of the roof rocks, an array of piezometers was installed in roof‐bolt holes at two locations within an underground coal mine in central Illinois. Pressure vs. time measurements were obtained from piezometer arrays located in areas of the mine ranging from dry to wet conditions. Data collected from the piezometers indicate that water drainage from a saturated sandstone above the coal is largely controlled by local structural and stratigraphic features, and these features determine the distribution of wet and dry areas in the mine. Hydraulic conductivities of the sandstone were determined in the laboratory and in situ from drainage profiles and from tests of instantaneous head changes. Results of these tests indicated that dewatering in front of mining would not be successful in this mine.
Seepage from Oilfield Brine Disposal Ponds in Utah
Authors: Baker F. G. , Brendecke C. M. 
Published: March 2006

ABSTRACTSignificant amounts of brine produced in conjunction with oil well operations in the Greater Altamont‐Bluebell field have been disposed of to surface impoundments. Mass balance calculations indicate that about 93% of this brine, a total of 4,430 acre‐feet (5·45 × 106 m3) over the ten‐year period studied, is lost through seepage, introducing a total salt load of 200 million pounds (90 × 106 kg) into the shallow aquifer system. Estimates of salt‐water plume movement indicate that potential adverse economic impacts on irrigators and other water users in the Duchesne River Valley could reach hundreds of thousands of dollars. Lining of disposal ponds and increased use of injection wells will reduce future contamination. A monitoring program should be set up to determine actual levels of contamination of domestic and agricultural water supplies.
Uses of Numerical Modeling in the Design and Licensing of Dewatering and Depressurizing Systems
Authors: Bair E. Scott , O'Donnell Timothy P. 
Published: March 2006

ABSTRACTNumerical models can be used to aid in the design and licensing of dewatering and depressurizing systems by simulating changes in hydraulic head produced by the interference patterns of various configurations and pumping rates of wells, wellpoints, or ejectors. The total quantity of water that must be pumped to achieve the desired objective can be approximated by modeling the inflow rate into a network of constant‐head nodes located around the perimeter of an excavation and assigning a hydraulic‐head value to these nodes equivalent to the average level to which the water table or potentiometric surface would be lowered by a dewatering or depressurizing system. As a result, it is possible to determine the decrease in the inflow rate as the flow system goes from the period of transient flow, when significant quantities of water are released from storage in unconfined aquifers and hydraulic gradients are steeper, to the period of steady‐state flow when no water is released from storage and hydraulic gradients are flatter. Based on the inflow rate data, simulations can be made showing the effectiveness of various pumping well configurations. In these simulations, the number, location, and pumping rates of wells can be varied to design a dewatering or depressurizing system that maximizes well interference and drawdown with a minimum number of wells. Decreases in the inflow rate during transient flow can be accounted for by adjusting well discharge rates during the transient flow period.Simulation results can be used to determine the radius of influence of the system, calculate induced drawdown in nearby wells, determine the amount of time required for predrainage prior to construction, calculate the amount of induced infiltration from nearby surface‐water
Major Ion Characterization of Coastal Saline Ground Waters
Authors: Howard K.W.F. , Lloyd J. W. 
Published: March 2006

ABSTRACTThe ages and origins of saline ground waters in coastal aquifers can be important indicators of local aquifer flow characteristics. Unfortunately, attempts to classify such waters using established trilinear diagram techniques are frequently inconclusive due largely to the dominance of sodium and chloride ions. In a study of saline ground waters from the Chalk limestone of eastern central England, an alternative, less conventional, dilution diagram procedure is employed which reveals previously unrecognized differences in local major ion chemical character. These differences are interpreted in terms of the origins of the saline ground waters and their histories of mixing. Significantly, the interpretations reinforce and, in some cases, refine earlier interpretations based on notably less extensive minor ion and environmental isotope data. It is concluded that the saline ground waters are associated with at least three periods of saline intrusion during the past 120,000 years.
Flow Pattern of a Karst Aquifer in the Molai Area, Greece
Authors: Ghikas Loannis Ch. , Kruseman Gideon P. , Leontiadis Loannis L. , Wozab David H. 
Published: March 2006

ABSTRACTAfter analysis of the geological, hydrological, hydrochemical, isotope, and pumping test data of the karst aquifer in the Mesozoic Tripolitza carbonates of the Molai area, it was concluded that the carbonates contain two flow systems. The western system discharges through the shore and submarine springs at Glyfada into the Gulf of Lakonia; its catchment, which has no exploitable reservoir, is connected to the springs by a narrow conduit related to a fracture zone in marbles that accompany the Molai fault. The eastern flow system, along the northern fringe of the Molai Plain, has a reservoir with acceptable (less than 120 m deep) pumping levels; its water quality, however, is variable. The system discharges, probably by dispersed seepage flow, into the Aegean Sea. The unusual characteristics of the karst in the Molai area can be explained by the continuous tectonic activity which has prevented the completion of various stages of karst development.
Ground Water for Oil‐Shale Development, Piceance Basin, Colorado
Authors: Alley William M. 
Published: March 2006

ABSTRACTVast deposits of oil shale are contained in the Piceance basin in northwestern Colorado. The basin may contain as much as 40 million acre‐feet of stored water associated with these deposits, much of which may have to be drained for mining. Yet, most analyses of watersupply for oil‐shale development have focused on surface water with only brief mention of ground water.This study used a synthetic streamflow model to investigate the effects of using conservative estimates of ground water on the required active storage capacity of a hypothetical reservoir on the White River. Results of the study indicate that use of ground water from mine drainage and/or auxiliary wells may have a significant impact on the size and timing of surface‐water reservoirs. Thus, ground water may be an important source of supply, particularly during early development of an oil‐shale industry. The study results strongly suggest that further investigations are needed on the physical availability of ground water as well as the institutional, legal and waterquality constraints on its use.
Steady Interface Upconing Beneath a Coastal Infiltration Gallery
Authors: Gupta A. Das 
Published: March 2006

ABSTRACTThe upconing of the salt‐water interface in an unconfined coastal aquifer due to water withdrawal by an infiltration gallery is analyzed numerically based on the variational formulation of the problem. Sometimes in coastal areas, from the point of view of safe withdrawal of water on a long‐term basis, the use of an infiltration gallery is found to be feasible in preventing severe upconing of the interface that would have resulted from heavy pumpage by a vertical well. The numerical procedure presented here is capable of delineating profiles of the free surface and interface along with the length of the outflow face and quantity of freshwater flow to the sea. Full consideration of the nonlinear boundary conditions on the free surface and interface is included for a steady flow towards a gallery in both isotropic and anisotropic aquifers. The extent of upconing of the interface under different operating conditions of the gallery for different aquifer geometries has been studied. A general understanding of the flow phenomenon in the vicinity of the gallery has been established. The results of the analysis can be used to plan a water withdrawal scheme without causing contamination by salt water.
An Emergency Hydrogeologic Evaluation of a Chemical Dump Site
Authors: Reuter Greg J. , Saunders Wayne R. , Dalton Richard F. , Althoff William F. 
Published: March 2006

ABSTRACTIn latter 1979, approximately 200 drums of assorted waste chemicals were dumped in a rural area of southern New Jersey. The spill site is underlain by a water‐table aquifer which is the source of potable water throughout the general area. Emergency response personnel of the New Jersey Department of Environmental Protection (NJDEP) began a surface cleanup soon after the dumping, and requested Department geologists to investigate the dump site.An integrated approach combining drilling and sampling, downhole logging, surface resistivity, ground‐water conductivity and laboratory analyses for the common organic solvents was used to promptly assess ground‐water contamination and the controlling hydrogeology. Using routine hydrogeologic techniques and standard field equipment, within four months the emergency spill had been assessed by Department geologists and the outlines of a ground‐water decontamination program were evident.
Pumping Effects of Wells in Fractured Granitic Terrain
Authors: Kohut A. P. , Foweraker J. C. , Johanson D. A. , Tradewell E. H. , Hodge W. S. 
Published: March 2006

ABSTRACTIn two documented cases, pumping of large‐capacity, 13 to 16 l/s (200 to 250 USgpm) irrigation wells completed in fractured granodiorite of Jurassic age resulted in the occurrence of trough‐like cones of depression extending up to 1,500 m (4,900 ft) away from the pumped wells. The longitudinal axes of the drawdown troughs developed along trends coinciding with areal intersections of the two prominent bedrock joint sets prevalent in the region and bisecting the angles between the sets. The drawdown troughs appear to extend preferentially away from the pumped wells in the general direction of increasing regional potentiometric head towards local recharge areas. Occurrence of this phenomenon indicates that fracture anisotropy in this terrain has a pronounced effect on the magnitude and direction of drawdown interference about a pumped well. To be effective, several monitor wells strategically placed may be required to adequately assess drawdown interference in crystalline terrain. Although large‐capacity wells may be effective in dewatering extended narrow zones in the granitic bedrock, several closely‐spaced pumping wells sited in series normal to the regional potentiometric gradient in conjunction with monitoring of peripheral observation wells are recommended as a first step in engineering situations where dewatering a large area of this type of fractured granitic body may be desired.
Updated Radioisotope Studies in Zimbabwean Ground Waters
Authors: Wurzel Peter 
Published: March 2006

ABSTRACTThe Sabi Valley alluvial plain is the largest tract of alluvium in Zimbabwe. The ground‐water hydrology of the alluvial plain was studied by three independent methods: the classical approach of potentiometric surface construction and pump test analyses, the use of in‐borehole velocity and direction measurements with artificial radioactive isotopes applied to the point‐dilution techniques, and a natural and thermonuclear tritium survey.The three methods of approach produce remarkably close values for the ground‐water throughflow within the plain. A safe yield figure of 2.5 cubic metres/sec is currently used with confidence for the ground‐water reservoir as a result of this study.
Velocity Plots and Capture Zones of Pumping Centers for Ground‐Water Investigationsa
Authors: Keely Joseph F. , Tsang Chin Fu 
Published: March 2006

ABSTRACTNonpumping monitoring wells are commonly installed and sampled to delineate the extent of a contaminant plume and its chemical character. Samples from municipal and private pumping wells are frequently collected during ground‐water contamination investigations as well. Pumping wells are also employed for remedial actions.To properly interpret sampling data from monitoring and pumping wells and to estimate their potential effectiveness in remedial actions, it is important to clearly define the geometry of that portion of the aquifer contributing water to the well (the capture zone). Velocity distribution plots by manual and computerized methods are illustrated and shown to be simple and of reasonable accuracy.
Experimental Study of Some Hydrogeophysical Properties of Unconsolidated Porous Media
Authors: Biella Giancarlo , Lozej Alfredo , Tabacco Ignazio 
Published: March 2006

ABSTRACTLaboratory investigations have been carried out on one‐ and two‐component artificial sand samples in order to estimate the relations between formation factor (F), porosity (φ), and permeability (K). The measurements were carried out by varying grain size and size distribution while keeping constant shape and packing; in our experimental conditions the measured formation factor approximated the intrinsic formation factor.The relationship between formation factor and porosity (F = a ·φ−m) is independent of grain size and size distribution; the coefficient values are: a = 1·15, m = 1·42.The relationship between permeability and formation factor has the general form K = r · F−s, where s is constant, and r is a function of the mean size d of the small component of the samples.The K‐F relation can be established only if d is constant; in these conditions the relationship is an inverse one, and the negative trend is related to the variations in size distribution.
Major Procedural Discrepancies in Soil Extracted Nitrate Levels and Nitrogen Isotopic Values
Authors: Lindau Charles W. , Spalding Roy F. 
Published: March 2006

ABSTRACTPreliminary vadose zone nitrate extraction experiments have revealed the extractant (2N KCl) volume affects the determination of nitrate and its nitrogen isotope ratio.In five cores, extractable NO3‐N concentrations increased an average of 1.7 times after the soil‐to‐extractant ratio was increased from 1:1 to 1:10. An increased extractant volume resulted in a large positive shift of stable nitrogen values (δ15N), which averaged +6.2%.An underestimation of available NO3‐N for leaching and transport through the vadose zone and a biased source interpretation from the δ15N values probably would occur if a procedure which leads to incomplete extraction of nitrate is used.
Monitoring and Mathematical Modeling of Contaminated Ground‐Water Plumes in Fluvial Environments
Authors: Osiensky James L. , Winter Gerry V. , Williams Roy E. 
Published: March 2006

ABSTRACTGround‐water monitoring to delineate a contaminant plume in fluvial hydrostratigraphic units often is uncertain. Fluvial deposits consist typically of interbedded layers of sands, silts and clays, with buried stream channel deposits of sands or gravels. The channel deposits are often interpreted erroneously to be discontinuous between test holes and in cross section due to their sinuosity. Erroneous conclusions pertaining to the areal continuity of these geometrically complex deposits are inevitable unless the investigator thoroughly understands the depositional environment(s).The hydraulic conductivity of buried stream channel deposits may be several orders of magnitude higher than the matrix materials in which they are enclosed. The higher hydraulic conductivity of buried stream channel deposits has potentially significant ramifications with respect to ground‐water monitoring to delineate the geometry of a contaminant plume migrating through these deposits.Ground‐water monitoring at uranium mill waste disposal sites located in fluvial environments began on a significant scale in about 1977. A uranium mill tailing disposal site located in such an environment in central Wyoming is among the first sites monitored. Thirty‐seven monitor wells were constructed at the site to delineate a seepage plume originating from one of the tailing ponds. This case history illustrates the need for a detailed under—standing of the hydrostratigraphy at a waste disposal site in order to interpret the meaning of ground‐water quality data effectively. Water quality data from monitor wells located on a hit or miss basis often are misleading. The hydrostratigraphic horizon from which a water quality sample is collected must be well defined before the sample analyses can be interpreted quantitatively.