ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03524.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTThere is a tendency during the verification stage of aquifer model building to manipulate stratigraphic boundaries. This procedure is acceptable insofar as the geohydrologist is sufficiently knowledgeable to sense the point at which the manipulations encroach upon the integrity of his model.Examples from the Maryland Coastal Plain are used to depict several types of stratigraphic boundaries. These include erosional truncation, overlap (or pinchout), disconformity, and facies change. Defining statements are given for each in order to clarify the stratigraphic implications of boundary modeling.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03525.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAcidic industrial wastes have been injected into deep wells in a limestone aquifer near Pensacola, Florida, since 1963. Prior geohydrologic studies in the area had indicated that the limestone aquifer contained nonpotable water and was overlain by an extensive clay confining layer.Two injection wells are presently being used to inject the waste at a rate of approximately 2,000 gallons per minute. The injection pressures are about 200 pounds per square inch. Over 3 billion gallons have been injected. Data from a current study indicate that the waste may extend outward about 1 mile from the injection wells, and pressure effects may extend outward more than 25 miles. Monitor wells show that pressure changes are following a predictable pattern. No wastes have been detected in a monitor well open to the Floridan aquifer immediately above the Bucatunna Clay Member of the Byram Formation and 100 feet from one of the injection wells.A monitor well open to the receiving formation was constructed about 1,300 feet south of the injection wells. Geochemical effects of the wastes were detected at this well about 10 months after injection began. In early 1968, the pH of the waste was lowered to about 3. Effects of this waste, which included a large increase in calcium, were detected at the monitor well about 5 months later.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03526.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe economic potential of the Mekong Delta is largely unrealized because of the harmful effects of uncontrolled flows of surface water which occur generally during the period August‐October. Interest in the Delta by various government agencies has resulted in preliminary plans for redistributing surface waters to control flooding, facilitate drainage, provide for irrigation, and prevent sea‐water encroachment. Current estimates indicate that construction costs in excess of a billion dollars would be required to develop an initial 2.1 million hectares (5.2 million acres) of the Delta to maximum economic potential; these costs do not cover those for upstream projects upon which the Delta developments depend.The Mekong Delta is underlain by an upper section of Recent alluvium, and a lower section of older alluvium. The older alluvium contains a permeable artesian zone called the 100‐meter aquifer, which is the most productive groundwater reservoir in Viet Nam. Tested well capacities range from about 145 to 635 gallons per minute (gpm); more efficiently designed wells should produce in the range of 500 to 1,000 gpm from this aquifer. Part of the 100‐meter aquifer is intruded by sea water.Current data permit no more than speculation with regard to storage, recharge, and flow in the 100‐meter aquifer. Storage is estimated to be approximately 30 million acre‐feet in the lower Delta, where the total dry season irrigation requirement is about 1.2 million acre‐feet. Piezometric levels in the Delta wells may be due merely to sea‐water pressure gradients acting across a horizontal saline‐fresh‐water interface; they do not necessarily imply ground‐water flow or an area of recharge.A major inconsistency exists in the relation of certain reported piezometric levels and corresponding depths to well intakes assuming conditions of either hydrostatic or hydrodynamic equilibrium, and it is necessary to postulate special circumstances to account for this. The data also indicate conditions conducive to subsidence, although no evidence for subsidence has yet been observed.The most feasible plan for development of the Mekong Delta may involve the conjunctive use of surface water and ground water of the 100‐meter aquifer, even though induced recharge and a ground‐water barrier against sea‐water intrusion might be necessary. Storage capacity is adequate, but more information is needed on recharge and total obtainable well capacities for the 100‐meter aquifer and on the possibilities for occurrence and control of subsidence in theeventof widesp

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03527.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA set of type‐curves is presented which simplifies and quickens the solution of the Rorabaugh equation for drawdown in a pumping well by eliminating the trial‐and‐error computations. Type‐curve analysis of test data in the field, before pumping is discontinued, provides an indication of the accuracy and adequacy of test data points. For optimum accuracy, test data should cover the portion of maximum curvature of the curve, and the range between the lowest and the highest pumping rates used in the step‐drawdown test should be great enough to define a uni

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03528.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03529.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTAn investigation was made of infiltration conditions in the alluvial‐filled Mad River valley in the vicinity of the Springfield municipal wells. The study shows that most recharge to the 100‐foot thick sand and gravel aquifer is from induced infiltration from the Mad River. Local precipitation and natural, down‐valley underflow also are important in sustaining the 14 mgd (million gallons per day) pumping rate.The investigation was designed to learn more about rates of streambed infiltration. Gaging stations were established at points above and below the well field in the expectation that infiltration losses could be measured directly. The attempt was unsuccessful because infiltration losses proved too small to measure accurately by ordinary stream gaging methods. The investigation has, nevertheless, provided much new data about this important watercourse aquifer system.Observation‐well records covering the 4‐year period 1965 through 1968 show that ground‐water levels follow an annual cycle, typically rising in the period February through June, when recharge exceeds depletion, and falling during the remainder of the year. The rate of induced stream infiltration is not sufficient to prevent perennial dewatering of the aquifer beneath the streambed. The water table beneath the center of the losing reach ranges in depth from about 17 feet in January to about 6 feet in June in the average year. Bedrock highs beneath the stream, which result in local thinning of the aquifer upstream and downstream from the well field, essentially limit infiltration to a reach about 2½ miles long having an area of approximately 24 acres. During the 7‐month depletion period average infiltration is estimated at 9 mgd and during the 5‐month accretion period estimated infiltration is 12 mgd. On the basis of these estimates the infiltration rate for the respective periods is 0.37 and 0.50 mgd per acre, or about 0.35 mgd per acre p

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03530.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03531.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTSeveral geophysical techniques have been specialized for applications to exploration for ground water in an insular basaltic environment. This article describes a multidisciplinary application of several such techniques to the Kona Coast of Hawaii in Hawaii. Aerial infrared scanning and low‐level aeromagnetic surveys were the major reconnaissance techniques. For detailed study, modified audiomagnetotelluric and D. C. resistivity profiling methods were used. The improved knowledge of subsurface structure confirmed the expectation that no large flows, such as suitable for commercial exploration, occur in that coastal secto

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03532.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1971.tb03534.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY