ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01365.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractDarcy's equation and unsaturated‐flow theory are used to calculate flow through earth linings that are placed in ponds or channels to reduce seepage. The procedure utilizes the relation between unsaturated hydraulic conductivity and pressure head of the underlying material as calculated from the measured saturated hydraulic conductivity and the relation between water content and pressure head. The method enables the selection of the liner (thickness and hydraulic conductivity) that will keep seepage below a certain maximum limit. Since the hydraulic conductivity of clays is affected by the cationic composition and the salt concentration of the soil solution, the chemical composition of the liquid moving through the liner must be taken into account. This applies also to other chemicals, including solvents and other organic compounds that may be in the water. Travel times of water from the surface impoundment to the underlying ground water are calculated from the seepage rate and the corresponding water content in the vadose zone. Accumulation of solids (mine tailings, for example) can further reduce the seepage from the pond. Proper design of waste‐water ponds also requires analysis of the response of the underlying ground water (mound buildup) and the movement of pollutants in the vadose zone and aquifer. In view of the high costs of earth liners, prediction of the seepage is necessary to make sure that the selected lining material, the thickness of the liner itself, and the method of construction will produce the desired resu

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01366.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTIn coastal areas salt‐water intrusion represents a significant threat to water quality in coastal aquifer systems. The electromagnetic method evaluated in this study proved to be rapid, very inexpensive, and it yields results which agree well with geologic and geochemical surveys using direct sampling. The instrument reads directly in conductivity units and the depth of investigation is constant for a particular spacing and orientation of the receiver and transmitter coils. Data can be obtained and interpreted by personnel with little technical training. Data interpretation normally involves producing terrain conductivity contour maps, but quantitative solutions can be obtained where the geoelectric section can be reasonably approximated by a two‐layer section. Some problems were experienced with interference. However, interference sources usually were very localized and could be avoided.This study, conducted in two areas of Florida, demonstrates that the EM conductivity method is very useful for rapid, inexpensive ground‐water surveys where the objective is to locate zones of conductive pore fluids at depths less than 30–40 meters. Although interpretation is indirect and qualitative, neither data aquisition nor interpretation require special training. This characteristic of the EM method makes it very suitable for use by agencies where highly‐trained technical personnel are not

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01367.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe U.S. Geological Survey maintains a computerized ground‐water site‐inventory (GWSI) file that contains information about wells and springs at sites from all States of the United States. This file contains data collected by U.S. Geological Survey personnel and personnel of cooperating State, local, and Federal agencies. The file is easily accessible to members or users of the National Water Data Exchange. Since the establishment of the GWSI file in 1974, the data base has grown 19 percent per year and contains information on about 770,000 sites as of February 1

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01368.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTInitial attempts to estimate unconfined aquifer parameters from a pumping test using an open observation borehole proved to be unsuccessful. However, when separate piezometers were installed along a vertical section, significant differences in ground‐water head were noted. These differences suggest that rather than providing an average ground‐water head, the open borehole provides a means of flow between the different elevations and therefore produces misleading results.The results for the separate piezometers are analysed using a numerical model, and reasonable values of the aquifer parameters are dedu

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01369.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTSeveral automated techniques for analyzing pumping test data have been published recently. These techniques usually require the services of a computer. With the advent of more sophisticated hand‐held calculators, it is possible to implement these techniques on calculators. This paper presents a program written for an HP‐41C. With two memory modules, up to 44 drawdown‐time pairs can be handled simultaneously. The “best” T and S in the least squares' sense is obtained. The complete Theis equation is used so there is no time or distance l

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01370.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTSignificant savings are frequently achieved from increasing well and pump efficiency by repair or replacement. Replacement analysis (a part of engineering economics) may be used to schedule these actions. The criterion is to maximize net benefits or minimize the cost of water. The optimal timing of repair or replacement occurs when the cost per unit of water from the old system becomes more than the minimum annualized cost per unit of water from the new system.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01371.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTA multidimensional, finite‐difference model for ground‐water flow and heat transport is used to analyze the thermal energy storage experiment conducted by Auburn University in Mobile, Alabama. The experiment consisted of three stages–namely, injection, storage and recovery occurring for 80, 51 and 41 days, respectively. This application demonstrates the validation evidence that the model adequately and accurately simulates the field experiment. The numerical model includes the effects of: hydraulic anisotropy, thermal convection and conduction, and heat loss to the adjacent confining strata. Observed aquifer isotherms at the end of each stage are compared with predicted values on a cylindrical grid situated about the well. The degree of vertical discretization used in the model is shown to impact the predicted temperature profiles at each stage, but has minimal effect on the recovery water temper

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01372.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe objective of this study is to demonstrate the application of a predictive ground‐water potentiometric‐head model to estimate the profitability of irrigation in contrast to that of dry‐land farming. Unit cost per acre‐foot of water required for a variety of crops is used to determine the distributive impact of predicted aquifer depletion at 5‐year intervals during 20 years of simulated pumping. A land‐use planning scheme is proposed for identifying areas (one square mile or less) where various crop types can be irrigated based on benefit‐cost criteria for two arbitrary pumping rates as well as on future energy and well development costs. Maps showing areas of profitable production are presented for cotton and alfalfa as examples of crops requiring as much as 1 and 2 ac‐ft/ac/yr (0.30 and 0.60 ha‐m/ha/yr), respectively. Irrigation‐water needs and related profitability are presented as examples for several crops

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01373.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTStable isotope and fluid chemistry investigations in complex hydrogeologic areas have proven useful in delineating the origin of thermal waters and their interaction with local ground‐water reservoirs. The application of these techniques is illustrated using water samples collected from all hot and warm springs and many of the wells in the East Shore area, Utah. These samples were analyzed for major cations and anions, oxygen‐18/oxygen‐16 and deuterium/hydrogen ratios.The data presented suggest the presence of at least two and perhaps three distinct hydrogeologic regimes. One regime involves fault‐controlled deep circulation of waters derived from high elevations in mountains toward the east. These waters evolved into the sodium plus potassium, chloride‐enriched hot spring fluids that are high in total dissolved salt concentration (greater than 4,000 mg/1), exhibit oxygen‐18 enrichment due to geochemical rock‐water interaction at depth and have deuterium/hydrogen ratios similar to high elevation mountain springs. A second hydrogeologic regime is comprised of waters derived from lower elevations that infiltrate into the shallow valley sediments. These dilute calcium plus magnesium, bicarbonate fluids comprise most of the area's ground‐water supply.Leakage of thermal waters into overlying cooler aquifers is observed in the vicinity of the hot springs, and is believed to occur in several other portions of the East Shore area. These leakage zones make up the third hydrogeologic regime observed in the

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01374.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY