bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydraulic Conductivity of a Fine‐Grained Till, Cattaraugus County, New York
Authors: Prudic David E. 
Published: March 2006

ABSTRACTHydraulic conductivity of a fine‐grained till was evaluated by field and laboratory techniques as part of a study of the movement of radionuclides at a nuclear‐waste landfill in western New York. In general, both methods produced similar results. Hydraulic conductivity values determined from (a) slug tests of piezometers, (b) several types of laboratory tests on cores, and (c) calculation from mercury porosimeter tests, agreed within a factor of 25.Slug tests were analyzed by two methods: one assumed horizontal flow to the piezometer screen; the other assumed spherical, isotropic flow. Average horizontal hydraulic conductivity from slug tests of 12 piezometers was 6 × 10−8 cm/s (2 × 10−9 ft/s) by the first method and 2 × 10−8cm/s (7 × 10−10ft/s) by the second.Laboratory tests of core samples were designed to determine the extent to which anisotropy and increased pressures with depth may affect hydraulic conductivity. Consolidation tests were done on four core samples to determine changes in hydraulic conductivity with pressure. Vertical hydraulic conductivity of the samples decreased by 40 percent as pressure increased from near atmospheric to the 7 kg/cm2 (100 psi), a pressure that would prevail at a depth of 30 m (98 ft). This indicates that hydraulic conductivity of the till decreases with depth in response to overburden pressure.Despite evidence of higher horizontal than vertical permeability in one set of laboratory tests of till samples, other laboratory and field tests as well as analyses of ground‐water flow by a computer model indicate that the till is nearly isotropic.Hydraulic conductivity of the till was estimated with reasonable accuracy from mercury‐porosimeter tests. However, estimating hydraulic conductivity of fine‐grained samples from some regions by this method may be inappropriate because the method uses dry samples, which could severely affect the results if swelling clays are present.
RISING GROUND WATER – PROBLEM OR RESOURCE?
Authors: Hagerty D. J. , Lippert K. 
Published: March 2006

Abstract. Ground water rising to within 6 m (20 feet) of average ground surface elevations in Louisville, Kentucky caused concern to municipal officials and building owners in the central urban area. An average rise of more than 11 m (35 feet) occurred between 1969 and 1980.An evaluation of foundation conditions and structural configurations in central Louisville indicated rising ground water could create:1. slight but significant possibilities of structural settlement problems;2. high possibilities of damage to basement floors and walls; and3. very high possibilities for disruption of utility conduits.Efforts to determine the cause of this rise in ground‐water level have focused on the historical relationships between ground‐water levels, pumpage rates and precipitation values.Historical data indicated that ground‐water levels in a system undisturbed by man could reach ground surface elevations in central Louisville. Preliminary studies indicated a strong relation between average ground‐water levels and changes in pumping rates and incident precipitation. A further detailed study showed extremely high correlation (R = 0.995) between average ground‐water levels in 1966–1980 and cumulative departures in precipitation and pumping rates from 1950–1965 average precipitation and pumping rates.A study of the feasibility of lowering ground‐water levels while simultaneously storing energy in the aquifer system was begun but was interrupted by devastating explosions of hexane in the sewers beneath south‐central Louisville on February 13, 1981. Although a dry year in 1980 and no change in pumping rate have slowed the rise in ground‐water level temporarily, long‐term solutions to this problem need to be developed.
Regional Study of the Dakota Aquifer (Darton's Dakota Revisited)
Authors: Helgesen J. O. , Jorgensen D. G. , Leonard R. B. , Signor D. C. 
Published: March 2006

ABSTRACTIn 1905, N. H. Darton described the geology and underground‐water resources of the central Great Plains in his classic report that emphasized the importance of the Dakota aquifer to this region of the United States. Since Darton's work, many investigators have studied Dakota‐aquifer hydrology with regard to development of local or statewide resources. Preliminary mapping of relatively recent fluid‐level data by the U.S. Geological Survey indicates regional potentiometric trends similar to those interpreted by Darton, but altitudes substantially lower in part of the area. The classic artesian‐system concept of the Dakota aquifer is not consistent with some of the data and observations of the past several decades. The simple aquifer geometry and effective lateral hydraulic continuity normally associated with that concept do not appear to characterize the Dakota aquifer regionally.
Permeability of Grout Seals Surrounding Thermoplastic Well Casing
Authors: Kurt Carl E. , Johnson Roy C. 
Published: March 2006

ABSTRACTAn experimental test program was conducted to measure the longitudinal permeability of a grouted thermoplastic water well casing system. A neat cement grout, with and without calcium chloride or bentonite admixtures, was placed in the annulus of a simulated well. Test pressure and specimen configuration was shown to influence the measured coefficient of permeability. A neat grout with a water/cement ratio of 2.0 had a much higher permeability coefficient than the same grout with a water/cement ratio of 0.46.Once the bond line between the grout and casing was broken, the permeability of the system was generally higher than for the initial test. Specimens with a bell coupling included had a slightly higher permeability than specimens with straight pieces of casing. The effect on permeability of the admixtures in the grout was not conclusive. However, the addition of a bentonite slurry to the test water was observed to decrease the permeability coefficient when tested under low pressure.The permeability coefficient of the basic neat grout casing system ranged from 20 – 100 × 10 −5 cm/sec at low test pressure. It was concluded that the casing has an impact on the longitudinal permeability of the system since the coefficients of permeability measured were significantly higher than other published values. However, the coefficients of permeability measured were in the range of soils with low permeability such as silts.
A Lumped Parameter Model of a Chalk Aquifer‐Stream System in Hampshire, United Kingdom
Authors: Keating T. 
Published: March 2006

ABSTRACTA field investigation into low flow augmentation using seasonal ground‐water abstraction from the unconfined Chalk aquifer in Hampshire, United Kingdom, revealed the presence of a thin, highly transmissive and storative zone in the Chalk close to the water table. A lumped parameter model of the aquifer‐stream system incorporating a variable transmissivity and storativity distribution has been developed to explain the unusual hydrogeological features of the catchment observed during the investigation.
The Nature and Source of Arsenic in Northeastern Ohio Ground Watera
Authors: Matisoff Gerald , Khourey Christopher J. , Hall John F. , Varnes Arthur W. , Strain William H. 
Published: March 2006

ABSTRACTElevated arsenic concentrations were found in ground water near Canal Fulton, Ohio. The hydrologie and chemical properties of the area were studied to determine the source of the arsenic and evaluate the possibility of a similar problem occurring elsewhere. Two major aquifer systems exist within the study area: the Sharon Sandstone of the upland areas; and the outwash sand and gravel deposits of the buried valleys. Ground‐water flow is generally from the north, but local variations are caused by the Tuscarawas River valley on the south and west of the study area. Within the study area, there is no evidence for an anthropogenic source of arsenic to the ground water. Agricultural soils, abandoned underground coal mines, industrial impoundments to the north, and an abandoned industrial dump site within the study area were all eliminated as possible sources for the arsenic. The arsenic in Canal Fulton ground water is entirely inorganic, consisting of about equal parts of arsenate and arsenite. Reduction‐oxidation (redox) considerations suggest that arsenic is controlled by an adsorption equilibrium with ferric hydroxides, and that the reduction of the ferric hydroxides by a recent lowering of Eh and/or pH in the aquifer has liberated both iron and arsenic to solution. A high correlation between ferrous iron and total dissolved arsenic supports this model. It is hypothesized that Eh conditions have been lowered in the aquifer by either the recent introduction of methane gas or the deposition of a thick layer of till during the last glacial retreat. The methane gas could be leaking from deep underground storage at the site and reducing oxidized compounds. The deposition of till would have eliminated local recharge of oxygenated waters.
A Computer Program for a Trilinear Diagram Plot and Analysis of Water Mixing Systemsa
Authors: Morris Michael D. , Berk Jeffrey A. , Krulik Joseph W. , Eckstein Yoram 
Published: March 2006

ABSTRACTThe Piper (1953) trilinear diagram has been widely used to graphically represent the dissolved constituents of natural waters and to test for apparent mixtures of waters from different sources. Because of the time required to plot points and calculate the proportional values of mixing, this treatment of data was often quite tedious, particularly in studies involving large numbers of chemical analyses. The PIPER program was written in BASIC to be run on a Hewlett‐Packard desktop computer with an X‐Y plotter. Data input is in ppm units. The program plots points in all three fields of the trilinear diagram, draws at each point within the central diamond field a circle with a radius correspondent to the concentrations expressed in meq/1, checks for points that fall on a straight line (or within a predetermined tolerance of a straight line) representing postulated mixtures with two end members, and/or within a triangle representing mixtures of three end members. Finally, the program does a numerical analysis of the mixing ratios of the constituents for postulated mixing systems according to the methodology as presented by Piper (1953).
Enumeration and Characterization of Bacteria Indigenous to a Shallow Water‐Table Aquifer
Authors: Wilson J. T. , McNabb J. F. , Balkwill D. L. , Ghiorse W. C. 
Published: March 2006

ABSTRACTRegions of the earth below the root zone of soil have conventionally been considered void of life. However, widespread pollution of ground water in the U.S. by organic compounds has kindled interest in the numbers of microbes that might be found in aquifers and associated regions of the deeper unsaturated zone, and in their ability to degrade organic pollutants.Newly developed techniques in microbial ecology allow the direct enumeration and examination of soil microbes without recourse to their cultivation on growth media. These techniques reduce many uncertainties associated with the use of culture media, such as the growth of contaminants or the failure of indigenous forms to grow on a particular medium. Samples were recovered aseptically from depths of 1·2, 3·0, and 5·0 meters (m) at the margin of a small floodplain near Lula, Oklahoma. Depth to the water table was 3·6 m; depth to bedrock was 6·0 m. Numbers of microbes were surprisingly similar at all three depths (3 to 9 × 106/g dry material). Although both Gram‐positive and Gram‐negative bacteria were encountered, small Gram‐positive coccoid forms predominated. No protozoa, yeasts, or other fungi were seen. The indigenous bacteria could rapidly degrade toluene. Chlorobenzene was degraded in material from the vadose zone, while bromodichloromethane was degraded in material from the saturated zone. There was no detectable degradation of 1,2‐dichloroethane, 1,1,2‐trichloroethane, trichloroethylene, or tetrachloroethylene.
The Practical Application of Surface Electrical Resistivity to Detection of Ground‐Water Pollution
Authors: Urish Daniel W. 
Published: March 2006

ABSTRACTOne of the primary problems in field investigations of ground‐water pollution is locating the contaminant plume. Drilling of sampling holes on a hit‐or‐miss basis is both time‐consuming and expensive. Under many subsurface conditions, surface electrical resistivity profiling can quickly and cheaply locate the general position of the plume and identify areas most feasible for sampling and monitoring. Many contaminants contain an ionic concentration considerably higher than the background level of native ground water. When such a contaminant is introduced into an aquifer, the electrical resistivity of the saturated soil is reduced. Surface electrical resistivity profiling across a suspected area can identify this reduced resistivity zone as an anomaly. The sensitivity of the method depends on relative uniformity of geology and topography as well as minimal extraneous electrical interferences. It is also essential that the “A” spacing used in the profiling procedure be carefully selected. If the resistivity contrast between contaminated and uncontaminated ground water is high, detection of at least the central part of the plume is likely within expected geologic variation. The method has been successfully used in the location of plumes from contaminants including brine, uranium reprocessing liquid wastes and landfill leachate in glacial deposits of New England.
Harmonizing Ghyben‐Herzberg Interface with Rigorous Solutions
Authors: Kashef Abdel‐Aziz I. 
Published: March 2006

ABSTRACTGround‐water management in coastal aquifers is becoming highly complex due to the increase in water demand coupled with the threat of salt‐water encroachment. The salt‐/fresh‐water interface produced by the natural flow of the aquifer is distorted as a result of ground‐ water exploitation. The solution of these problems includes several simplifications of unknown effects. This paper deals with the first phase in ground‐water management, namely locating the interface due to natural flow by simple equations which give results practically the same as the rigorous solution.During the last four decades, the use of the Ghyben‐Herzberg (G‐H) principle to determine the salt‐/fresh‐water interface in coastal aquifers was questioned by many investigators due to the neglect of the water movement. Some of the highly complex solutions which were later introduced are reviewed in this paper and compared with the G‐H results for a very wide range of parameters. It has been found that the G‐H principle is valid for practical purposes and that the differences between location of the interface predicted by the G‐H principle and those determined by the rigorous solutions may be less than the differences resulting from small errors in the field records of water levels.For exceptionally high natural velocities and/or for more precision within the zones very close to the shore, two simple equations derived on the basis of the rigorous solutions are given. Each equation is written in terms of the practically popular G‐H solution with a correction factor added. The results of these equations are tabulated in dimensionless values for practical use. Moreover, the extent and size of the fresh‐water lens can be determined from the field records of one or two shallow observation wells. An illustrative example is given to clarify the procedure.
Hydrogeology of the Littlefield Springs, Arizona
Authors: Trudeau Douglas A. , Hess John W. , Jacobson Roger L. 
Published: March 2006

ABSTRACTA hydrogeologic investigation was conducted to determine the source of recharge to the Littlefield Springs, a series of carbonate springs occurring along a 10 km (6 mile) reach of the Virgin River in northwestern Arizona. The most probable sources of recharge to the springs were determined to be influent Virgin River water and precipitation within the springs hydrologic basin. These recharge sources could account for the total discharge of the springs. The Littlefield Springs have essentially constant discharge 1.84 cms (65 cfs), and quality 2940 mg/L TDS. Tritium analyses of the spring and river water indicate that there are at least two different sources of recharge to the Littlefield Springs–one a minimum of 22 years old and the other younger than 22 years old. Analysis of the influent Virgin River upstream from the springs indicates a 1·42 cms (50 cfs) loss at 2130 mg/L TDS and the same ionic ratio of dissolved constituents as the springs. The travel time of this recharge source is interpreted to be a minimum of 22 years. Local recharge to the springs has been estimated to be 0·31 cms (11 cfs). The presence of local recharge is indicated by pulse train gaging of the springs, and by water quality at a well upstream of the springs and at the first upstream occurrence of the springs. The travel time of this recharge source is interpreted to be less than 22 years.
Aqueous Geochemistry and the Exchangeable Cation Composition of Glauconite in the Aquia Aquifer, Maryland
Authors: Chapelle Francis H. , Knobel LeRoy L. 
Published: March 2006

ABSTRACTThe cation composition of water in the Aquia aquifer of southern Maryland changes systematically in the direction of ground‐water flow. In the upgradient parts of the aquifer, calcium is the dominant cation in solution. Between 10 and 20 miles downgradient, calcium and magnesium are dominant. Between 20 and 35 miles downgradient, magnesium and potassium are dominant, and, beyond 40 miles downgradient, sodium is the most abundant cation in solution. The exchangeable cation composition of glauconite in the Aquia aquifer changes systematically in the direction of flow in a manner similar to the changes in water chemistry. These observations are interpreted as evidence that cation exchange reactions are processes that simultaneously alter water composition and glauconite composition along the flowpath.Exchange parameters K’and n for glauconite in the Aquia aquifer were determined for the reactions:
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The exchange parameters for each reaction were tested by an indirect method. Molar ratios of exchangeable cations or glauconite were calculated from water chemistry data using the derived k’and n values. In each case, the trend of calculated molar ratios compared favorably with measured molar ratios. The calculated exchange parameters demonstrate that the exchange process is not linear for the Ca2+ ‐Na+ and Mg2+ ‐Na+ ion pairs.The sum of exchangeable cations on glauconite samples is significantly lower in the outcrop area than downgradient. Corresponding to this, the concentration of dissolved silica and dissolved oxygen in Aquia water is high near the outcrop area and decreases downgradient. This pattern suggests that incongruent dissolution of glauconite is an additional process that modifies glauconite composition near the outcrop area but is less important downgradient.
Survival of Pathogenic and Indicator Organisms in Ground Water
Authors: Bitton G. , Farrah S. R. , Ruskin R. H. , Butner J. , Chou Y. J. 
Published: March 2006

ABSTRACTA comparative study was undertaken on the decay rates of three bacterial types (S. typhimurium, E. coli and S. faecalis), an enterovirus (poliovirus type 1) and a bacterial phage (f2) in ground water maintained under laboratory conditions. Except for f2 phage, all the microorganisms tested were relatively stable in ground water. S. faecalis survived best among all the bacteria tested and its decay rate was similar to that of poliovirus type 1.Under field conditions, bacterial indicators were also found to be stable in the ground‐water environment. The decay rate for fecal streptococci was lower than for fecal or total coliforms in the shallow wells.
Field Determination of Cation Exchange Properties for Calcareous Sand
Authors: Reardon E. J. , Dance J. T. , Lolcama J. L. 
Published: March 2006

ABSTRACTA technique has been developed for the determination of the exchangeable cation population of calcareous sandy material with cation exchange capacities of less than 1 meq/100 g. The technique involves the addition of exchange salt in the dry state to samples of porous media using original pore water as the exchange salt solvent. In applying this technique to samples from below the water table, the amount of pore water available for reaction is reduced by centrifuging in the field to bring the moisture content close to field capacity values. By utilizing the minimum amount of pore water, interferences during the exchange process due to calcite precipitation or dissolution are minimized. The extent of calcite dissolution or precipitation that occurs can be appraised by measuring alkalinity or total carbon on the pore water before and after addition of the exchange salt. Three salts, NH4C1, CsCl and LiCl were tested for their suitability for this technique. CsCl was found to be preferable because of its low tendency to dissolve carbonate and the preference of Cs+ on exchange sites.Application of the method to a field site in southern Ontario yielded a value of 0.51 ± 0·09 meq/100 g over 15 samples for the cation exchange capacity of a near surface glaciofluvial sand deposit. It is believed that this technique could be applied with reasonable accuracy and reproducibility to materials with exchange capacities of as low as 0·1 meq/100 g.
Analysis of Flow to a Large‐Diameter Well Discrete Kernel Approach
Authors: Patel S. C. , Mishra G. C. 
Published: March 2006

ABSTRACTUnsteady flow to a large‐diameter well has been analyzed by a discrete kernel approach, taking well storage into consideration. The variation of drawdown with time has been obtained at the well and inside the aquifer. The validity of the new method has been verified by comparing the drawdown at the well with the drawdown given by Papadopulos and Cooper (1967). The aquifer contribution to discharge at various times has been estimated.
Rapid Solution of the Nonlinear Step‐Drawdown Equation
Authors: Miller Cass T. , Weber Walter J. 
Published: March 2006

ABSTRACTThe step‐drawdown test is frequently utilized by hydrogeologists as an aid in assessing well efficiency and approximate pumping capacity. Unfortunately, the analysis of step‐drawdown data presently requires either a solution to a system of highly nonlinear equations or the application of tenuous assumptions relative to the solution form. A method for solution is derived which does not require limiting assumptions, type‐curve methods or extensive computer facilities.