ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01420.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe U.S. Geological Survey is studying the potential for storage of heated water in a sandstone aquifer in St. Paul, Minnesota. The efficiency of the aquifer to store thermal energy is related, in part, to the hydrogeologic characteristics of the aquifer. The movement of heat away from the injection well is directly related to the anisotropy. Aquifer tests were conducted to determine the anisotropy near the heated‐water injection well. The maximum and minimum values of transmissivity along the principal directions of the hydraulic conductivity tensors of the Ironton and Galesville Sandstones in St. Paul, Minnesota are approximately 1,090 and 480 feet squared per day. The storage coefficient is 4.5 × 10−5. These values represent the average of four determinations of nonsteady flow to a well in an idealized infinite anisotropic aquifer. Analysis of the values of transmissivity and storage coefficient for hypothetical changes in location of two of the monitoring wells where depth‐deviation surveys were not available indicates that computed transmissivities vary less than 5 percent and storage coefficients vary less than ±6

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01421.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTFlow simulations supplemented resource evaluation studies of the Lower Greensand aquifer. The annual recharge has hitherto been considered to be the resource available for development although a large confined storage exists. Pumping is principally in urban areas but recent monitoring suggests that the aquifer may have suffered excessive drawdowns. Therefore, simulation studies were carried out to refine the annual recharge estimate, to define the past effects of pumping and to obtain an indication of future trends. Catchment water balance indicates average annual recharge of 28 × 106m3. One‐dimensional (ID) ground‐water flow simulation suggests that regional abstractions affect outcrop‐water levels. The study showed that the aquifer reached a new equilibrium with the current pumping regime. An improved insight to the aquifer has permitted the formulation of strategies for future resource devel

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01422.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe acceptability of the hypothesis of Darcian flow through a semiconfined carbonate aquifer was tested prior to running a multiple‐day aquifer test in Pinellas County, Florida. The approach used to test the hypothesis was to run a number of hour‐long aquifer tests at different discharges with drawdown measured at the same time during each test in two observation wells, one at 35 feet and the other at 733 feet from the pumped well. If the hypothesis were acceptable, a plot of drawdown versus discharge should describe a straight line.A linear relation was described in 15‐minute and 1‐hour data plots of drawdown versus discharge for both observation wells. Thus, the hypothesis of Darcian flow through the semiconfined carbonate aquifer was deemed acceptable. Drawdown data from the distant observation well collected during the following multiple‐day aquifer test were then analyzed for aquifer‐property values of transmissivity, storage coefficient, and leakance coefficient using standard methods. Discharge for the multiple‐day test was within the discharge range of the ho

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01423.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTA 43‐acre watershed in Muskingum County, Ohio, was studied to determine the hydrologic consequences of strip mining for coal. A quantitative description of the effects on the ground‐water flow components of the hydrologic system has been obtained using digital models.The premining watershed was characterized by nearly flat‐lying sedimentary rocks of the Pennsylvanian System. Underclay beneath the two major coal beds formed bases for perched zones, creating three separate aquifers. Recharge to the ground‐water system occurred mainly by percolation of precipitation. Most of the discharge from the top and middle aquifers occurred by downward leakage to the underlying aquifers. A smaller amount of discharge occurred as springflow or streamflow near the intersections of the underclays and land surface.Mining has destroyed the top aquifer, and has replaced the bedrock by spoil material. Water levels in the spoils are at a much lower altitude than existed in the premining top aquifer because of a combination of (1) a larger hydraulic conductivity, (2) areal variations of the hydraulic characteristics of the confining bed, and (3) a slower rate of recharge from precipitation caused by removal of vegetation and soil compaction. Covering of previously exposed portions of the middle aquifer and a lower hydraulic head in the spoils has allowed less recharge to the middle aquifer. Additional flow is induced across the western boundary of the watershed and has reduced the outflow across the eastern boundary. Discharge from the middle aquifer as downward leakage and streamflow is less than before

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01424.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe seepage meter and the mini‐piezometer were utilized in an attempt to evaluate ground‐water reservoir interactions over a 12‐month period at Echo Bay in Lake Mead. In conjunction with these techniques three standard piezometers, refraction seismic data, and water chemistry data were utilized to interpret seepage device results. During a four‐month period, from December 1979 to March 1980, an 8 ft (2.5 m) rise in reservoir stage, the reservoir contributed water to Echo Wash bank storage at rates of up to 0.29 gpd/ft2(12 lpd/m2). Ground‐water discharge occurred for the remainder of the project, during a stage decline from April 1980 to May 1980, a rise in June 1980, and leveling off and slight decline for the remainder of the year, July 1980 to December 1980. The maximum seepage meter ground‐water discharge rate of 3.0 gpd/ft2(122 lpd/m2) was recorded in December 1980. Seepage meter water chemistry data for June were similar to Lake Mead water chemistry and were interpreted to be previously recharged Lake Mead water. September water chemistry data showed two possible components of ground‐water discharge, a high SpC calcium sulfate Echo Wash ground water and a lower SpC Lake Mead recharged bank storage water. December ground‐water chemistry data showed discharge to be a high SpC calcium sulfate water similar to Echo Wash ground‐water quality which was apparently unaffected by Lake Mead inflow. Mini‐piezometer data were collected at each seepage meter site. However, these data usually did not provide correlative results with seepage meter data probably because of suspended sediment in the piezometer water column and plugging of the perforated tip. Seepage meters were successfully utilized to characterize reservoir ground‐water in

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01425.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTIn using least‐squares parameter estimation techniques to solve for hydrogeologic parameters, one may use a weighting function to reflect differing reliabilities of head measurements. In studies published to date, the weighting function has been used in anad bocmanner or not at all. The inverse square of the observed hydraulic gradient, adjusted to reflect the modeler's perception of geologic heterogeneity and data reliability, is typically an appropriate weighting functio

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01426.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTAn exact expression is derived for the optimal spacing between interfering wells in a rectangular well field in an ideal confined aquifer. A simple, practical method for determining the optimal spacing is presented. The optimal spacing is shown to be substantially different from the spacing determined by use of the Theis formulation. The economic savings resulting from use of the revised approach are evaluated and found to be considerable, especially when the number of wells is large and the transmissivity of the aquifer low.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01427.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTDirect mirror‐well image theory to locate an impermeable boundary does not apply in anisotropic formations because the relationship between flow lines and equipotential lines is distorted due to directional transmissivity. A simple approach enables an impermeable boundary to be located in anisotropic formations, and it can be verified with a field exampl

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01428.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTEffective management of a ground‐water system requires description and prediction of the transport and fate of contaminants in that system. This can be facilitated by using mathematical models which accurately represent the physical phenomena operative in the system. One of the most significant phenomena impacting the transport of many organic pollutants is partitioning between the solid (soil) and aqueous (ground‐water) phases.The tendency of a contaminant to partition may be roughly approximated from measurements of such constitutive properties as the octanol: water partition coefficient of the contaminant and organic carbon content of the soil. Such rough approximations provide a basis for cursory appraisal, but are inadequate for quantitative system descriptions, particularly where nonlinear equilibrium sorption, kinetically dependent partitioning, or irreversible and/or hysteretic phase distribution phenomena are operative. Accurate simulation of solute transport frequently requires the incorporation of kinetic parameters and/or a nonlinear isotherm relationship to define transport phenomena in the fundamental equations governing mass transport. Laboratory measurements may be utilized to assess sorptive factors of importance, kinetic properties of an organic solute and a soil system, and equilibrium partitioning relationships. Such measurements can be utilized to provide more accurate modeling of contaminant transp

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1984.tb01429.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY