ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03480.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTSelenium is a trace metal naturally occurring in soils derived from some sedimentary rocks. Upon oxidation to the selenate ion, it can percolate to ground water and be assimilated by plants. Effects upon human health have not been clearly established—a low selenium diet is beneficial, while high doses can produce undesirable physical manifestations. Neither extreme dietary deficiency nor toxicity is apparent in the human population of the United States. The maximum contaminant level of 10 μg/1 adopted in the National Interim Primary Drinking Water Regulations is not justified by recent studies and should not be enforced by the Environmental Protection Agency without new scientific evidence demonstrating that naturally occurring selenium is a health hazar

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03481.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTPumpage from shallow aquifers, primarily dolomite bedrock, in northeastern Illinois has exceeded estimates of ground‐water recharge in extensive areas creating concern that ground‐water recharge estimates are too low. Pumpage increased 92 percent during the period 1966‐1978 and was 61.7 million gallons per day (2.33 × 108liters/day) during 1978. During the period 1966‐1979 water level declines exceeded 30 feet (9.14 meters) in some areas. Based on a ground‐water budget study, it was determined that recharge estimates were in the right order of magnitude and pumpage in excess of recharge was balanced by water taken out of storage from the shallow aquifers. A specific yield of 0.017 was determined for the dolomite bedrock aquifer based on the ground‐water

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03482.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTPumping from a dolomite aquifer adjacent to Lake Michigan has reversed the natural hydraulic gradient so that lake water has been induced to flow into the aquifer. Because lake water is muchlower in dissolved solids than the ambient ground water, the induced recharge is traceable as adistinct plume of high‐quality water over a mile long. The configuration of the plume allows interpretation of the hydraulic connection between the lake and the aquifer. Most of the induced recharge enters the aquifer through the lake bed at locations where the most permeable parts ofthe aquifer are overlain by relatively thin lake‐bed sediments which, in turn, are at least partly sand and gravel. It continues inland along zones of high hydraulic conductiv

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03483.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThis is the first of two articles on calculator programs for inverse solutions of the Theis equation.Newton's method is used to solve the Theis equation in terms of its principal well function argument parameters. The resulting iteration formulas are incorporated in an otherwise conventional polynomial‐based drawdown program for Hewlett Packard HP 67/97 calculators.The calculator program can solve, in addition to conventional drawdown problems, those problems requiring treatment of the time, distance, storage coefficient, or transmissivity as a dependent variable. Example calculations are shown and program modifications providing for series‐based well function calculations are appen

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03484.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThis is the second of two articles on calculator programs for inverse solutions of the Theis equation.Newton's method is used to develop an iteration formula for the determination of transmissivity and storage coefficient values from a combined Theissian expression that incorporates the information contained in two independent aquifer test data point sets.The algorithm is used in a polynomial‐based program for Hewlett Packard HP 67/97 calculators that is designed to process data corresponding to the full practical range of Theis well function arguments and to accept measurements from one or two observation wells, or from entirely different tests of a given aquifer. Program modifications providing for series‐based well function calculations are appended, and example calculations are sh

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03485.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTEquilibria studies of ground‐water chemistry in a synclinal basin at Three Forks, Montana indicate that most waters in the Tertiary sediments and Madison Group carbonates are calcium‐bicarbonate, or calcium‐sulfate waters which are supersaturated with respect to calcite. Calcium concentrations range from 13 to 426 mg/l, bicarbonate concentrations range from 112 to 328 mg/l and sulfate concentration varies between 29 to 114 mg/l. Sodium concentration is between 10 and 312 mg/l, producing sodium‐bicarbonate waters in some areas.Water‐level data were used to construct a potentiometric map that shows flow direction to the east. The water evolution along the flow path is from calcium‐bicarbonate in the recharge areas, to calcium‐sulfate in the center of the area, and finally sodium‐bicarbonate in the discharge area. This evolutionary sequence can be explained by calcite, dolomite and gypsum dissolution, ion exchange, sulfate reduction and dilution by recharging waters from the Elkhorn Moun

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03486.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTA generalized aquifer simulation program is designed and developed to handle problems connected with different kinds of complex ground‐water systems on microprocessors. The characteristic aspect of this program, involving the “Strongly Implicit Procedure” is that it requires only 10K bytes of memory for the generated code.Using this program, the effect of pumping on an aquifer can be studied for multiple pumping periods and predictions or observations can be scrutinized at various time steps within each pumping period. The program can also handle conversion problems between confined and water‐table aquifers under leaky or nonleaky states along with the effects of evapotranspiration, constant recharge or discharge boundaries. The utility and precision of the program have been tested using a sample problem quoted by Trescottet al

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03487.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTHigh Radon‐222 (222Rn) concentrations exist in ground water from most granitic rocks in Maine. Some values exceed the suggested limit of 500 pCi/1 (E.P.A., 1976) by more than 100 times. Although high values (x̄= 22,100 pCi/1) are conclusively linked with the granites, high values are also present in ground water in metasedimentary rocks from sillimanite‐ (x̄= 13,630 pCi/1) and sillimanite‐orthoclase zone metamorphic terrains. Metamorphic (anatectic) pegmatites with hydrothermally introduced uranium are thought to be the source of radon in high grade terrain. At lower grade (chlorite to staurolite), no relationship exists between222Rn content and metamorphic grade, although each rock formation has a somewhat characteristic222Rn range from ground water, ranges which overlap. Considerable local222Rn variations exist within the same rock body, reflecting local geologic and hydrologic conditions. Data on well depth, type of well, well yield, overburden type and thickness, and water chemistry show that222Rn may increase slightly with well depth up to 50 to 75 m and is essentially constant thereafter. Low yield wells, generally associated with areas of thin overburden, tend to have higher222Rn values than high yield wells, normally associated with thick sand and gravel overburdens.222Rn concentrations decrease with increasing sodium concentrations, suggesting that low222Rn wells are closely linked with surface waters. No other chemical parameter (Na, K, Ca, Mg, Fe, Mn, Zn, and Cu) correlates with222Rn content within a single ro

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03488.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe major water‐bearing units in the Houston district are the Chicot and Evangeline aquifer systems. Both systems consist of discontinuous layers of unconsolidated sand (aquifers) separated by clay layers.Extensive pumping has caused large declines of potentiometric surfaces in and around Houston. The declines have caused both the compaction of clay layers, which has resulted in land‐surface subsidence, and the movement of salt water towards Houston.During the early 1960's, an electric analog model of the district was made. The model simulated water‐level declines; but more importantly, the model indicated that the available data and conceptual model of the hydrologic system, consisting of two aquifers, were not totally adequate to allow simulation of the ground‐water systems.During the early 1970's, a second electric analog was built. The second model used new data and a conceptual model consisting of two aquifer systems simulated water‐level declines quite accurately, but the model was unable to accurately simulate the spatial distribution of water yielded from clay storage.A digital model was then developed during 1979 to simulate the hydrology of the district. The digital model used five layers and accurately simulated the hydraulic heads in both aquifer systems and land‐surface

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03489.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY