bluuebunny/crossref_metadata_2025 huggingface dataset:
Family Systems Training in Psychiatric Residencies
Authors: Berman Ellen , Heru Alison M.
Published: August 2005

Both extensive research and common sense dictate that attention to families is necessary for appropriate care of psychiatric patients. However, training in family skills has often been difficult to integrate into psychiatric residency programs because of conflicting paradigms, turf battles, constraints of time and money, and confusion over whether family‐centered care or family therapy should be taught. Current changes in residency accreditation mandate that family skills (not necessarily family therapy in its sophisticated form) be part of all residency programs. This article reviews the history of systems training in residencies, current accreditation requirements, and the GAP proposal for family systems skills, knowledge, and attitudes that that are teachable within the limited time available to residents. The application of these core skills is described using a case example and formulation. Challenges in teaching and ways of overcoming programmatic constraints are outlined.
Training in Family Psychology: A Competencies‐Based Approach
Authors: Kaslow Nadine J. , Celano Marianne P. , Stanton Mark
Published: August 2005

After providing an overview of the family psychology landscape and the competencies‐based movement in professional psychology, attention is paid to eight family‐specific competencies in the following areas: the application of scientific knowledge to practice, psychological assessment, psychological intervention, consultation and interprofessional collaboration, supervision, professional development, ethics and legal issues, and individual and cultural diversity. Effective strategies for providing family‐focused education and training to psychology trainees at the doctoral, internship, and postdoctoral levels and to psychologists through continuing professional education in these core competency domains are provided.
Infiltration and Hydraulic Conductivity of a Compacted Earthen Liner
Authors: Albrecht K. A. , Cartwright K.
Published: August 2005

Infiltration through a small (3 × 9 × 1 m) experimental earthen liner, similar to those used for waste disposal was evaluated. The liner was constructed using full‐size compaction equipment, and in‐situ ponded infiltration rates were measured using two large (1·5‐m diameter) sealed double‐ring infiltrometers. An average apparent steady‐flux density of 1·5 × 10−7 cm/s was achieved after two to three weeks. Wetting front depths of 7·3 cm and 9·6 cm after 46 days were calculated assuming a Green‐Ampt piston flow infiltration system. One of the infiltrometers was ponded with water containing rhodamine dye and after the 46‐day infiltration test, a uniform rhodamine dye front was observed at about the 4‐cm depth. Sharpness of the dye front suggests that the piston flow assumption is a reasonable one. Apparent saturated hydraulic conductivity of the liner was estimated from the infiltration data to be no more than 3·6 × 10−8 cm/s, meeting the present EPA permeability requirement for earthen liners of no more than 1 × 10−7 cm/s. Transit time for the wetting front to reach the liner bottom at the 0·91‐m depth was predicted to be about three years. Seepage flux after liner saturation was estimated at 4·8 × 10−8 cm/s for a liner ponded with 30 cm of water.
Creation of an Artificially Produced Fracture Zone to Prevent Contaminated Ground‐Water Migration
Authors: Begor Kristen Franz , Miller Michael A. , Sutch Rodney W.
Published: August 2005

Recovery of contaminated ground water in a fractured bedrock system presents some unique problems. Typically, the most common problem occurs from the inability to adequately characterize the discrete fractures through which contaminants may be migrating. Without adequate characterization, difficulties arise in properly positioning recovery wells and verifying the performance of the system. To overcome these difficulties at a site in Upstate New York, an innovative approach was developed involving the creation of an artificial fracture zone through controlled blasting to intercept contaminated ground‐water flow.

Site investigations delineated the extent of a ground‐ water contamination plume migrating within a fractured bedrock aquifer (Medina sandstone) which underlies approximately 15 ft of glacial till. A 72‐hr aquifer test involving one recovery well resulted in a low yield (3.5 gpm with 20 ft of drawdown). Data collected from adjacent observation wells indicated poor interconnection among the naturally occurring fractures. Although the response of some observation wells mirrored that of the recovery well, others showed little or no response to pumping. Therefore, achieving the corrective action objectives (i.e., preventing further contaminant migration and removing and treating contaminated ground water) would be difficult using a “traditional” multiple recovery well system. It was decided that controlled linear blasting could provide the enhanced fracture interconnection necessary to successfully intercept the contaminated ground‐water plume, which would then be captured and removed by judicious placement of recovery well(s) installed within the fracture zone.

Using a carefully controlled single line pattern blasting technique, a 6‐ft wide, 300‐ft long fracture zone was created in the upper 25 ft of the bedrock aquifer perpendicular to the centerline of the plume. Following fracturing, a second 72‐hr aquifer test was conducted at the same location and under conditions similar to the first test. The second test indicated that the single recovery well located in the newly created fracture zone should be fully capable of recovering contaminated ground water and preventing further migration of the plume. The recovery well produced a substantially higher yeild of 18.5 gpm with only 11.2 ft of drawdown. Futhermore, all of the nearby observation wells showed significant response to pumping.

Success at this site is promising, and the approach may prove useful at other sites involving contaminated bedrock aquifers.
Determination of Aquitard/Aquiclude Hydraulic Properties from Arbitrary Water‐Level Fluctuations by Deconvolution
Authors: Neuman Shlomo P. , Gardner David A.
Published: August 2005

A deconvolution method is proposed for the estimation of aquitard/aquiclude vertical hydraulic diffusivities on the basis of water‐level measurements in piezometers completed both in the confining layer(s) and in neighboring aquifers. The water levels may fluctuate in an arbitrary manner which is not necessarily caused by a prescribed pumping regime (as required in conventional pumping tests). A simple formula from the literature can be used to correct the measured water levels for time lag in the piezometer response. If the specific storage of the confining material is known from laboratory consolidation tests, the hydraulic diffusivity estimates can be translated into vertical hydraulic conductivities. The method is illustrated with the aid of a case study from southern California and is shown to yield robust parameter estimates.
Modeling Ground‐Water Management Options for Small Limestone Islands: the Bermuda Example
Authors: Thomson James A.M.
Published: August 2005

Small oceanic limestone islands represent a unique hydrogeological environment. High transmissivities and small land areas cause the average water‐table relief to be of the order of cm, while permitting larger diurnal and barometric sea‐level changes to penetrate the aquifer. Extremely accurate surveying and monitoring at observation wells and tedious data reduction are necessary to obtain representative water levels.

Numerical modeling of island aquifers, while largely in its infancy, can be an excellent focus for research, and ultimately a useful management tool. Essential inputs to an island model are barometric changes in oceanic base level and a thorough assessment of recharge.

In Bermuda, the main ground‐water lens provides 4500 m3/d of ground water for public supply. Because of the importance of this resource, the Bermuda Public Works Department has invested in a ground‐water monitoring and research program. As part of this, a well‐evaluated example of an island aquifer model has been developed.

Bermuda is generally typical of this hydrogeological environment, but differs from other small islands in two ways: (1) internal marshes, major discharge areas elsewhere, act as barriers to ground‐water flow; and (2) development of a high density of housing (typical of only a few small oceanic islands) has significantly increased Bermuda's recharge, because of domestic waste water and road drainage contributions.

A number of aquifer management options were tested by the Bermuda model. Steady‐state modeling results suggest that an increase in abstraction to 8500 m3/d without serious derogation is possible. Such a policy would increase the vulnerability of the lens to point‐source pollution, and should therefore be gradual, monitored, and combined with stronger measures for pollution prevention.
The Geohydrology of Mars
Authors: Risner Jeffrey K.
Published: August 2005

The recent advances in space science have now made it possible to construct models of the existence. volume, and hydrologic cycle of the ground water of the planet Mars.

Outgassing models of water vapor indicate that the surface of Mars should be covered with water to a depth of 10 to 100 meters (1·4 × 1015 to 1·4 × 1016m3). Geomorphic evidence suggests a depth of at least 500 meters (7 × 1016 m3) of water should occur over much of the planet, yet no surface water, other than glacial ice at the poles (2·3 × 1015 to 9 × 1015 m3), exists today. Martian gravity, though only 40 percent of Earth's, would keep water from escaping the planet. A survey of surface and atmospheric water volumes indicates that the majority of water, 1·2 × 1016 to 6 × 1016 m3, is hidden as ground water.

Hydrologic cycle models indicate that Mars has an active but near static hydrologic cycle, dominated by water discharge in desert lowlands and water recharge at the ice‐ covered poles. Ground‐water flow plays a major role in this system.
Characterization of Ground‐Water Flow by Field Mapping and Numerical Simulation, Ross Creek Basin, Alberta, Canada
Authors: Ophori D. U. , Tóth J.
Published: August 2005

Hydrogeological mapping and numerical simulation techniques have been used to characterize the flow of ground water in Ross Creek Basin, Alberta, Canada. Forty percent of the basin's ground water is recharged in the Cypress Hills and discharged through local, intermediate, and regional flow systems at lower topographic elevations north of the hills. The remaining 60 percent is recharged through randomly distributed areas of restricted sizes. The similarity between the flow patterns mapped in the field and simulated numerically is an indication that the mapping technique is useful in determining ground‐water flow patterns throughout the various climatic regions in the Alberta prairies. Ground‐water discharge was found not to be restricted to the thalwegs of the main drainage ways, Ross and Gros Ventre Creeks, and their tributaries. Consequently, measurable base flow cannot represent the total discharge of ground water, which is estimated to be 2·0 × 10−4 m3/s or 22 percent of the total precipitation in the basin. There is evidence that soil development has been influenced by ground water in this area.
Preliminary Evaluations of Regional Ground‐Water Quality in Relation to Land Use
Authors: Cain Doug , Helsel Dennis R. , Ragone Stephen E.
Published: August 2005

The U.S. Geological Survey through its Toxic‐Waste— Ground‐Water Contamination Program began studies during 1984 to evaluate the degradation of regional ground‐water quality as a result of human activities. The studies are designed to quantitatively relate human activities, expressed as land use, to the quality of ground water at a regional scale.

Preliminary results from six of the studies in New York, New Jersey, Connecticut, Florida, Nebraska, and Colorado summarized in this paper indicate that regional ground‐water quality has been affected by human activities. The frequencies of detection of volatile organic compounds and some trace elements were larger in ground water underlying urban or industrial areas in comparison to undeveloped areas. Ground water in agricultural areas generally had larger concentrations of nitrate and had an increased frequency of detection of pesticides in comparison to undeveloped areas. Effects of human activities on water quality increased as the intensity of urbanization or irrigation increased. Ground‐water pumpage, waste‐water discharges into a stream that is hydraulically connected to an alluvial aquifer, and consumptive use of ground water affected the ground‐water quality in one study area to a greater extent than land‐use practices.

These preliminary results indicate that in specific areas, surficial nonpoint sources, expressed as land use, have altered regional ground‐water quality. Additional studies are being made to determine if these results are consistent and widespread.
FLOW DIRECTIONS WITH A SPREADSHEET
Authors: Kelly William E. , Bogardi Istvan
Published: August 2005

Abstract. Direction of flow is determined by a least‐squares fitting of plane surfaces to measured water levels. The calculated coefficients yield the corresponding components of the gradient vector. The method can be implemented for two‐ or three‐dimensional flow using a spreadsheet program More than the minimum three or four measurements for two‐ or three‐dimensional flow can be included in the calculation. The method is flexible and easily tailored to particular field applications.
Storage Basin Volume and Drainage Basin Dynamics: Camas Prairie, South‐Central Idaho
Authors: Cluer Brian L.
Published: August 2005

A recent tectonic model and subsequent gravity survey and basement modeling have raised questions concerning the size of the Camas Prairie ground‐water storage basin and the hydrodynamic properties of the Camas Creek drainage basin. This paper addresses storage basin dimensions using an anomalous mass determination from a plot of residual gravity, and presents estimates of recharge and underflow from a mass‐balance study. Underflow may transport much of the water [2·73 (105) acre‐feet/yr] (ac‐ft/yr) calculated as residual in the mass‐balance study, and transport is from the Camas Prairie storage basin south to the Snake Plain Aquifer via permeable strata in the Mount Bennett Hills surface drainage divide. Results of the anomalous mass study suggest that the volume of ground water stored in the Camas Prairie basin is 39 (106) ac‐ft, considerably greater than previously estimated. Similarly, recharge to the Camas Prairie basin is estimated at over 7(105) ac‐ft/yr, one order of magnitude greater than earlier estimates.
Unified Management of Surface‐ and Ground‐Water Quality Through Clean Water Act Authorities
Authors: Duda Alfred M.
Published: August 2005

Existing institutions for protecting surface‐ and ground‐water quality provide uneven results across the nation. Pollutants are transferred across media and political boundaries, important contaminants are not addressed, important sources of pollution are not controlled, and accountability in achieving measurable objectives is not assured. Examples from the seven‐state region served by the Tennessee Valley Authority (TVA) document the wide range of ground‐water contamination issues facing the nation and the importance of interconnections between subsurface and surface waters–both hydrologically and institutionally. National legislation seems imminent to overcome institutional barriers that promote fragmented, ineffective, and expensive approaches.

Unified management of subsurface‐ and surface‐water quality makes both hydrologic and institutional sense for dealing with cross‐media, cross‐agency linkages causing water pollution. Congressional testimony presented by TVA suggests that this unified water quality management can be achieved through a narrow amendment to the Clean Water Act requiring state adoption of (1) surface‐ and subsurface‐water classification systems, (2) surface and subsurface numerical standards, and (3) conjunctive surface‐ subsurface‐water quality management programs. National minimum program requirements, federal funding, and federal program/facility compliance would provide leadership in creating new local/state/federal partnerships targeted to priority geographic areas. In this way, the state comprehensive program would become the hub around which the spokes of all different environmental and natural resource management (technology‐based control) programs with surface‐ or ground‐water quality implications would be integrated. This proactive water quality management approach would be less costly to the public than existing reactive approaches which have left taxpayers with a half trillion dollar remedial action bill for cleaning up our surface‐ and ground‐water resources.
Correlations of Permeability and Grain Size
Authors: Shepherd Russell G.
Published: August 2005

Previous theoretical and empirical investigations of the relation between particle size and intergranular permeability have resulted in the well‐known formula for intrinsic permeability (k)
image

where d is particle diameter, and c is a dimensionless constant. Statistical power regression analyses were per‐ formed on 19 sets of published data on size and laboratory permeability of unconsolidated sediments. The exponent of grain diameter ranged from 1.11 to 2.05, but most values were significantly less than 2.0. Results indicate that the permeability/grain size relation alternatively may be expressed, from an empirical basis, as

image

Values of c and the exponent both generally decrease with decreased textural maturity and increased induration.
Shape Factors for Permeability Tests in Boreholes and Piezometers
Authors: Chapuis Robert P.
Published: August 2005

Several sets of values are available for the shape factor of the cylindrical injection zone used to perform a field permeability test. Depending on the selected value, the resulting difference for hydraulic conductivity may reach 40% for long intake zones, and more than 100% for short intake zones. The commonly used shape factor is that given by Hvorslev (1951). Seven other factors derived from numerical models are now available: they differ from Hvorslev's factor by up to 100%. Three possible reasons for the differences are examined. Reference is made to Laplace's equation and related mathematical results derived before 1945. Shape factor values obtained by numerical methods are shown to be more or less accurate solutions of particular cases when impervious or recharging boundaries exist close to the injection zone. Their influence upon the shape factor value can be calculated analytically, as shown in a detailed example. Analytical shape factor equations are given for a cylindrical injection zone with either a pervious or an impervious bottom. Based on the method of image wells, two other equations are established to correct the shape factors if draining (constant head) or impervious layers are known to be located close to the injection zone. These equations should be used for field permeability tests in boreholes or piezometers.
Modeling Transport of a Degradable Chemical and Its Metabolites in the Unsaturated Zone
Authors: Tim Udoyara S. , Mostaghimi Saied
Published: August 2005

A mathematical model for transport and transformation of a pesticide and its metabolites in the soil is presented. Mechanisms for convective‐transport, hydrodynamic dispersion, ionic exchange, biological degradation, and hydrolysis are accounted for in the mathematical formulation. The major assumptions used in developing the model include: flow in the soil is in the vertical direction and one‐ dimensional, soil system is homogeneous and isotropic, volumetric water content and Darcy's flux are constant in time and space, and a linear reversible Freundlich isotherm describes the concentrations in the aqueous and adsorbed phases. Based on the outlined assumptions and Laplace transform techniques, analytical solutions for the concentrations of the parent material and its metabolites are presented. The applicability and potential of the model are demonstrated by predicting the transport and transformation of aldicarb (a nematicide of agricultural significance) and its metabolite, aldicarb sulfoxide, in the soil.
Use of Geophysical Logs to Estimate Water Quality of Basal Pennsylvanian Sandstones, Southwestern Illinois
Authors: Poole V. L. , Cartwright K. , Leap D.
Published: August 2005

Fresh water is found at depths up to 1000 feet in basal Pennsylvanian sandstone aquifers along the southern margin of the Illinois Basin. These aquifers, though not highly productive, represent a significant potential source of ground water in a region of very limited ground‐water supplies. A pilot study was undertaken in southwestern Illinois using geophysical logs and limited hydrologic data to evaluate the potential of these aquifers. Water quality, porosity, and permeability were estimated from the geophysical logs; these data were then used in conjunction with data from aquifer performance tests to delineate zones of potable water. The data indicate that fresh‐water lenses extend basinward in sandstone paleochannels.
Accurate Estimation of Conductivity of Water from Geoelectrical Measurements— A New Way to Correct for Clay
Authors: Park Stephen K. , Dickey Stephen K.
Published: August 2005

We propose a new way to correct estimates of solution conductivity for the effects of clay in a rock. The bulk electrical conductivity of a rock is dependent on its porosity, the conductivity of the pore fluid, and its clay content. Archie's law relates the bulk electrical conductivity to the first two factors only. The third factor, clay, enhances a rock's conductivity through surface conduction, and simple application of Archie's law will lead to overestimates of the solution conductivity. The enhancement due to clay can be estimated from measurements of induced polarization, however, and the bulk conductivity of the rock can be corrected. This correction will then lead to a more accurate estimate of the solution conductivity. Both resistivity and induced polarization can be measured by geophysical techniques. Interpretations of geophysical data are inherently nonunique, however, unless wells are correlated with the data. The method proposed here requires calibration with subsurface samples from at least one location. We have tested the method we propose to correct for clay in an area already sampled by monitoring wells. The corrections lead to substantial improvements in the correlation between solution conductivities from wells and from geophysical measurements. We are not proposing replacement of wells with geophysical soundings. Rather, the geophysical measurements, which are obtained at a fraction of the cost of a well, can be used to site wells and minimize the amount of drilling needed.
Geochemical Variations in a Core of Hydrogeologic Units Near Freehold, New Jersey
Authors: Pucci Amleto A. , Owens James P.
Published: August 2005

Solutes were determined for 26 pore‐water samples extracted from Tertiary and Cretaceous core material from a 1,320‐foot‐deep test borehole at Freehold, New Jersey. The cored materials are sediments that form a multilayered aquifer system of seven aquifers and eight confining units in the New Jersey Coastal Plain. The sediments are of marine origin in the upper 650 feet of the core and primarily nonmarine below 650 feet. Total concentrations of silica and major anions (SO4‐2 and Cl‐) and cations (Ca+2, Mg+2, total Fe, Mn+2, Na+, and K+) in the pore‐water samples varied with depth. Three core intervals are defined by water‐ chemistry variations, the environment of deposition (marine or nonmarine), and the degree of alteration (weathered or unweathered) of the units. Calcium, magnesium, sulfate, and total‐ion concentrations were greater in the midcore (unweathered marine) interval than in the upper (weathered marine) and lower (fluviodeltaicsilicate) intervals of the core. Generally, pore‐water chemical types in confining units were distinct from those found in aquifers–particularly in the midcore interval. In this interval, observed variations in pore‐water chemistry in part reflect carbonate dissolution and cation exchange reactions common in Coastal Plain sediments. However, high concentrations of sulfate in unweathered marine sediments indicate novel processes may be important factors influencing pore‐water chemistry in confining units.
Ionic Composition of Vadose Zone Water in an Arid Regiona
Authors: Rice R. C. , Bowman R. S. , Bouwer H.
Published: August 2005

The ionic composition of water in the vadose zone of the Salt River Valley in south central Arizona was studied for three different water regimes: desert, irrigated, and flooded by urban runoff. The desert area exhibited high salinity in the top 10 m, probably due to concentration of salts over several years. Below 15 m, the salinity decreased with depth and approached the salinity of the native ground water. For the irrigated area, the chemical composition of the soil water was similar to that of the applied water but concentrations were higher. The irrigation efficiency calculated from the salinities of the irrigation and soil water was 78%.The average NO3‐concentration from five of six sites was 100 mg/l, but was as high as 24,000 mg/l at another. Soil water from the urban runoff site had an electrical conductivity that was about three times less than that from the irrigated site, showing the effect of leaching with rain water. The observed salt distributions in the vadose zone were reasonably correlated to land use at the sites sampled.
The Occurrence of Perennial Seaward Seepages of Potable Water in Parts of Niger Delta, Nigeria
Authors: Amadi P. Abi‐Bezam
Published: August 2005

The water‐supply scheme in many rural and periurban communities in the Niger Delta of Nigeria occurs as underground seaward seepages that are under cover of sea water about twice daily all the year round. Their shoreline environment notwithstanding, they remain soft and fresh throughout the year, and they are slightly acidic with pH ranges from 5·0 to 6·0. Partial chemical analysis shows that the pattern of changes in the geochemistry of the seaward seepages between seasons differs markedly from that of the ground water of the Niger Delta. The observed pattern suggests that these potable seepages do not originate from the ground‐water regime of the Delta but from another portion of the hydrologic cycle that probably involves some seaward‐bound underground streams which, due to changes in lithology or to the gradual land‐to‐sea break of slope or both, have been forced to surface at the coastal tip as seepages.
Automated Calibration of a Contaminant Transport Model for a Shallow Sand Aquifer
Authors: Holmes K. John , Chu Wen‐sen , Erickson Denis R.
Published: August 2005

This paper presents an application of an automated calibration technique for the United States Geological Survey Method of Characteristics (USGS‐MOC) code. The model was applied to a shallow sand aquifer where contamination due to leakage from a solvent recycling plant was detected. Using available water‐table observations, transmissivity parameters for the USGS‐MOC model were calibrated by an automated parameter identification (PI) technique. Dispersivity was determined from trial‐and‐error simulations. For comparison purposes, the transmissivity parameters were also independently calibrated by trial‐and‐error simulations. The study results show that, although the PI‐calibrated model can produce water‐table contours that are in good agreement with observations and the contaminant plumes produced by the USGS‐MOC using parameters determined from the PI technique and the trial‐and‐error approach are not vastly different, the parameters determined by this technique are not considered to be physically plausible in all cases. The best strategy in model calibration would be to use both methods conjunctively.
An Approach to the Field Study of Hydraulic Gradients in Variable‐Salinity Ground Water
Authors: Hickey John J.
Published: August 2005

Understanding what can and cannot be determined about hydraulic gradients in field studies of variable‐salinity ground water is becoming increasingly important because of the use of subsurface injection as a waste‐disposal method in saline aquifers throughout the country. A field study approach is proposed for reliably estimating hydraulic gradients in subregions within a region of variable‐salinity ground water. It is based upon Hubbert's concept about the kind of density distributions that are required for ground water to have a potential. The approach consists of dividing a region of variable‐salinity ground water into subregions with constant density, subregions with only vertical variations in density, and subregions with vertical and lateral variations in density before determining magnitude and direction of hydraulic gradients. Subregions with constant density and subregions with only vertical variations in density according to Hubbert can have a potential; because of this, hydraulic gradients in such subregions may be reliably estimated. Subregions with vertical and lateral variations in density according to Hubbert may not have a potential; because of this, hydraulic gradients in such subregions cannot be reliably estimated. The approach was applied to an unconfined coastal aquifer and also to a confined and layered coastal aquifer that is used for subsurface injection. As the two applications show, the analysis of water levels and pressures from subregions with constant or approximately constant density and the analysis of pressures from subregions with only vertical variations in density provide simple and direct means for deducing the characteristics of hydraulic gradients within a region of variable‐salinity ground water.
Application and Comparison of Shallow Seismic Methods in the Study of an Alluvial Aquifer
Authors: Ayers Jerry F.
Published: August 2005

Seismic refraction, common‐offset, and common‐depth‐point methods were applied to an area on the flood‐plain of the Platte River in east‐central Nebraska to map the configuration of the bedrock surface, determine the thickness of the alluvial overburden, and define the hydrostratigraphy of the aquifer. Refraction results indicate a complex channelized bedrock surface that ranges in depth from 15 m to 40 m. At most stations, seismic velocities determined for the bedrock could be used to distinguish between rocks of the Dakota Group and Pennsylvanian‐age limestones and shales. Bedrock is overlain by alluvium with velocities typical of saturated sediments. A near‐surface clay unit was identified at a few refraction stations. Seismic velocities measured for the saturated sediments were used, in conjunction with an empirical relationship between velocity and bulk density, to obtain an estimate of 0.25 to 0.43 for the bulk porosity of the aquifer.

A comparison of survey results shows that depths to bedrock obtained from the three methods are in good agreement where coincident measurements were made. The comparison also shows that the relief along the bedrock surface is defined in greater detail using reflection techniques, particularly the common‐depth‐point method. The shallow limit of investigation for the common‐offset method, at least for the field conditions present in the lower Platte Valley, is about 15 m, or one‐half of the limit previously considered by other workers.
Well Location in Capture Zone Design Using Simulation and Optimization Techniques
Authors: Ahlfeld David P. , Sawyer Charles S.
Published: August 2005

A new computational methodology for capture zone design for contaminated ground‐water remediation is described. This method has been implemented in a computer model which utilizes both simulation and optimization techniques. The procedure determines the well locations and pump rates which will produce a desired ground‐water flow field at minimum cost. In this paper, the design procedure is described along with an example of its use on a hypothetical aquifer system. Numerical experiments are presented which determine the effect on remediation cost of alternate well locations. It is found that different well locations can have a major impact on the overall cost of remediation.
A Geoelectrical Investigation for Ground Water in Crystalline Terrains of Central Bahia, Brazil
Authors: Medeiros Walter E. , de Lima Olivar A. L.
Published: August 2005

The best locations for water wells in crystalline terrains of semiarid lands are narrow, densely fractured and altered belts, normally associated with fault zones and folding axes. A simple electrical procedure, based on vertical soundings and multiple resistivity profiling, has been successfully applied for the structural mapping of these two‐dimensional aquifers in northeast Brazil. The apparent resistivity sections constructed from partial electrical sounding measurements taken at a closely spaced interval along a traverse were interpreted using a finite‐difference algorithm. This scheme allowed detailed description of the lateral and vertical extent of fractured aquifers and some of their hydrogeophysical characteristics. The results of a selected case study from Bahia state compare satisfactorily with available geophysical logs and production data of existing wells.
Laboratory Studies of the Flow of Some Organic Solvents and Their Aqueous Solutions Through Bentonite and Kaolin Clays
Authors: Abdul A. S. , Gibson T. L. , Rai D. N.
Published: August 2005

A laboratory study was undertaken to evaluate the flow of the following organic solvents and their aqueous solutions through bentonite and kaolin clays: benzene, toluene, p‐xylene, nitrobenzene, trichloroethylene, tetrachloroethylene, ethyl acetate, 2‐butanone, and phenol. In each experiment, one pore volume of a 0.005 N CaSO4 solution (water) flowed through the clays, followed by several pore volumes of an aqueous solution of one of the organic solvents, and then by about three pore volumes of the neat organic solvent. The hydraulic conductivity for the aqueous organic solutions was not significantly different from those for water, and ranged from 4.6 × 10‐7 to 14.4 × 10‐7 and from 0.6 × 10‐7 to 0.8 × 10‐7 cm/sec through the kaolin and bentonite clays, respectively. The flow of the neat solvents through either the bentonite or kaolin clay increased by up to two orders of magnitude. The aqueous solutions did not change the physical appearance of the clays. In general, the more hydrophobic solvents caused the clays to shrink, producing distinct large vertical cracks. The hydrophilic solvents typically caused the clays to aggregate and fracture, forming a network of cracks. The kaolin clay appeared to aggregate more readily than the bentonite clay. The higher swelling of the clays in water than in the neat organic solvents likely caused the physical changes in the clays and the rapid flow of the neat solvents through them.
Use of Resistivity Soundings to Determine Landfill Structure
Authors: Carpenter P. J. , Kaufmann R. S. , Price B.
Published: August 2005

Sixteen Wenner and Schlumberger array electrical soundings were made over portions of the Mallard North landfill in DuPage County, Illinois, to map the gross layered structure of a closed landfill. Sounding curves were fit to standard type curves and values inverted in a least‐squares procedure to yield multilayer geoelectrical models. Wood, newspaper, cloth, glass, plastic, and metal refuse interspersed with soil exhibited resistivities of 9–19 ohm‐m (unsaturated) and 2–7 ohm‐m (leachatesaturated). Mature unfractured clay‐till cover material exhibited a resistivity of about 30 ohm‐m, and its thickness was estimated to within 27% of its true thickness. Larger errors were encountered over fractured and freshly emplaced cover. Soundings were also inverted to yield accurate leachate levels and refuse thicknesses (errors for both averaged about 30%). While Schlumberger and Wenner soundings produced models with comparable accuracy, Schlumberger soundings were less sensitive to cover heterogeneities and easier to deploy. Moore's cumulative resistivity interpretation method was found to be unreliable in interpreting this type of resistivity data. Fractures present in the cover material, lateral changes in leachate level, and variations in cover thickness and resistivity contributed to errors in interpretation. Despite these limitations, models generated from electrical resistivity soundings are reasonably accurate in their depictions of internal conditions in this type of landfill. Such soundings could be used to map internal structure in other layered landfills that lack construction and operational records.
Measurement and Interpretation of Low Levels of Dissolved Oxygen in Ground Water
Authors: White Art F. , Peterson Maria L. , Solbau Ray D.
Published: August 2005

A Rhodazine‐D colorimetric technique was adapted to measure low‐level dissolved oxygen concentrations in ground water. Prepared samples containing between 0 and 8.0 μmoles · 1‐1 dissolved oxygen in equilibrium with known gas mixtures produced linear spectrophotometric absorbance with a lower detection limit of 0.2 μmoles · 1‐1. Excellent reproducibility was found for solutions ranging in composition from deionized water to sea water with chemical interferences detected only for easily reduced metal species such as ferric ion, cupric ion, and hexavalent chromium. Such effects were correctable based on parallel reaction stoichiometries relative to oxygen. The technique, coupled with a downhole wire line tool, permitted low‐level monitoring of dissolved oxygen in wells at the selenium‐contaminated Kesterson Reservoir in California. Results indicated a close association between low but measurable dissolved oxygen concentrations and mobility of oxidized forms of selenium in the shallow aquifer which were in general electrochemical disequilibrium.
Field Evidence for the Effect of Acetate on Leachate Alkalinity
Authors: Devlin J. F.
Published: August 2005

Alkalinity measurements are routinely conducted as part of standard water–quality determinations. Often, very little interpretation of the values is attempted, and the entire alkalinity is attributed to carbonate or bicarbonate. When landfill leachates are involved, this assumption could be misleading in terms of plume mapping, determining the incrustation potential of the water, or assessing the likelihood of methane generation because substances other than carbonate, for example acetate, can contribute significantly to the sample's alkalinity.

A set of landfill leachate samples was collected and analyzed for alkalinity and volatile fatty acids. Acetate was the only organic acid identified. A very strong correlation was observed between acetate and alkalinity. Actual titration curves (volume of acid vs. pH) were compared with curves calculated assuming that acetate and bicarbonate were the two major species contributing the total alkalinity. Excellent agreement was observed between the experimental and theoretical data. Distinct differences in the shapes of the curves for carbonate–dominated and acetate‐dominated alkalinities make it possible to distinguish these two classes of water solely on the basis of alkalinity measurements. Water containing acetate titrates with an equivalence point which is less distinct than water containing only carbonate.
Determination of Specific Storage by Measurement of Aquifer Compression Near a Pumping Well
Authors: Robson S. G. , Banta E. R.
Published: August 2005

Aquifer tests of confined aquifers in deep formations can yield inaccurate specific–storage and storage‐coefficient estimates if the distance between the pumped and observation wells is imprecisely known. The distance between the wells can be uncertain because small deviations in the vertical alignment of deep wells can markedly change the distance between the perforated intervals of the wells. Uncertain distance between wells may seriously degrade the accuracy of specific‐storage or storage–coefficient values calculated from aquifer–test data obtained from closely spaced wells.

A method is proposed whereby compression of the aquifer matrix can be measured during an aquifer test and used to calculate specific‐storage and storage–coefficient values without knowledge of the distance between the pumped and observation wells. In a field trial of the method, specific–storage and storage‐coefficient values calculated from aquifercompression data were 8.16 × 10 ‐7 and 3.04 × 10 ‐4, which is nearly identical to values (8.04 × 10 ‐7 and 2.99 × 10 ‐4) obtained from longer–term monitoring of aquifer barometric efficiency. Additional comparison with results of a Theis analysis of drawdown data indicates that the aquifer compression data may provide a more accurate determination of specific–storage and storage–coefficient values than would be possible even if the vertical alignment of the pumped and observation wells had been surveyed.
The Shallow Weathered Fracture Layer in the Near–Stream Zone
Authors: Gburek W. J. , Urban J. B.
Published: August 2005

The bedrock profile of an east–central Pennsylvania watershed contains a shallow weathered fracture layer. To begin quantifying the effects of this fracture layer on ground–water movement, two valley cross sections were chosen for detailed investigation. One section represents the typical upland watershed situation where the regional ground water is in contact with the stream for only part of the year, while at the other section the regional ground water is in perennial contact with the stream. Rock cores extracted from the sections reveal a pattern of extensive fracturing to approximately 50 ft directly under the stream thinning to a relatively uniform 30–ft deep fracture layer away from the channel. Limited seismic investigations support these observations. Piezometers within each cross section show that hydraulic conductivity differs between the shallow fracture layer and the relatively unfractured zone below and that there is great variability in conductivity within the fracture layer itself. Lateral flow generally occurs within the fracture layer to within approximately 50 ft of the stream; here a converging flow pattern indicates ground–water discharge to the stream. Under wet conditions, the stream in each section serves as a point of ground‐water discharge, while under dry conditions, the more upland section shows no ground–water discharge to the land surface. Rather, subsurface flow is likely occurring beneath and parallel to the channel controlled by a discharge point at some downstream location. Finally, water–quality samples from the piezometers indicate a direct effect of overlying land use on water quality within the shallow fracture layer.
Evaluation of Aquifer Behavior and Characteristics in the Singrauli Coalfield, Central India
Authors: Choubey Vishnu D. , Shankaranarayana I.
Published: August 2005

Hydrological 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

The 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.