ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03392.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTGround‐water modeling begins with a conceptual understanding of the physical problem. The next step in modeling is translating the physical system into mathematical terms. In general, the final results are the familiar ground‐water flow equation and transport equations. These equations, however, are often simplified, using site‐specific assumptions, to form a variety of equation subsets. An understanding of these equations and their associated boundary and initial conditions is necessary before a modeling problem can be formu

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03393.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTIt has been demonstrated that a microcomputer costing less than $10,000 can accommodate a ground‐water basin model with a large number of nodes. Analyses indicate that finite difference and finite element models with several hundred nodes also can be accommodated. Microcomputers have several advantages over the larger and much more expensive macrocomputers as ground‐water basin modeling tools: easy to learn language used for programming, simplicity of operation, and low costs leading to easy access by investigators and users. Because of these advantages, willing investigators can learn to do modeling work by using a microcomputer and also write programsto computerize time‐consuming tasks and thus effect substantial manpower cost sa

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03394.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTThe low organic concentration and high specific surface area that characterize ground‐water recharge environments allow biofilms to predominate microbial kinetics. Consideration of the kinetics of substrate utilization and growth of biofilms indicates that microbiological activity occurs very near the injection well. The aggregate substrate expressed, for example, as chemical oxygen demand, can be considered the primary substrate; the biofilm's growth is supported through the utilization of the aggregate primary substrate. Individual trace organic compounds, none of which could support biofilm growth alone, are utilized as secondary substrates. Although biodegradable, secondary substrates that have slow utilization kinetics will pass through the biologically active zone undegraded. Field data from the ground‐water recharge project in Palo Alto, California, illustrate that naphthalene and heptaldehyde are biodegraded, while other compounds, such as chloroform and chlorobenzene, pass through the biologically active zone without biodegradat

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03395.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTField investigations in Paradise Valley, Arizona, conducted during 1974 and 1977, delineated areas of ground water with up to 132 mg/1 nitrate. Two alternative interpretations are developed as to possible sources of the excess nitrate. The first is a conventional interpretation identifying the use of nitrogenous fertilizers as the primary source and disposal of treated waste‐water effluent as a secondary source. An alternative interpretation identifies the source as a sand and gravel unit that is interpreted as a braided‐stream deposit, located about 152 m (500 ft) below the land surface. The source of the nitrate may have been NH4Cl leached from tuffs in the adjacent Superstition Mountains, subsequently oxidized to nitrate and deposited in abandoned channels of the braided‐stream complex. At present, it is not possible to make a definitive choice among the possible nitrate so

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03396.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTIn‐hole tracer tests were used in a geohydrologic investigation of metamorphic rock at the Savannah River Plant near Aiken, South Carolina, to locate water‐transmitting fractures and to determine the connectivity of these fractures between boreholes. Only after development of a conceptual model of the fracture occurrence and connection could the proper methods of analysis for the hydraulic parameters be selected.In‐hole tracers were used to locate fractures in a borehole and supplemented other methods, such as core inspection, geophysical logs, borehole wall imaging techniques, dry drilling, and packer tests. The first three of these do not necessarily investigate fluid‐transmitting fractures.In the study of the connectivity of fractures between boreholes, the in‐hole tracer techniques supplemented determinations by the rapidity of hydraulic response and the use of between‐well tracer tests.In hydraulically transmissive rock, fractures were located by changes in the velocity of the tracer pulse in response to adding fluid to the well. In virtually impermeable rock, the movement of the tracer pulse in the rock was normalized to the movement of another tracer pulse in the cased portion of the well because the movement was so slow that direct measurement was difficult. Connectivity of fractures between boreholes was determined by placing an in‐hole tracer in one hole and measurin

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03397.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTMonitoring the chemistry of ground water nearin‐situuranium leach mines is complicated by chemical variations unrelated to the mining operation that result from (1) spatial differences in the aquifer environment, and hence, in the water chemistry, (2) inconsistent or inadequate sampling procedures, and (3) errors in chemical analyses. Differences in the chemistry of water from place to place in the aquifer should be identified in pre‐mining baseline studies and must be taken into account during monitoring of the leaching operation, because natural waters of chemistry different from that established at a particular well during the baseline sampling period may be drawn into the monitoring well by pumping. The most important factor in developing proper sampling techniques is the configuration of the well and pumping equipment; if the pump intake is set near the point where water enters the well, and if the pumping rate is kept low to reduce turbulent mixing of waters in the well, it is not necessary to pump a full well‐bore volume before collecting a sample. Errors in chemical data can be eliminated by proper storage and handling of the samples and by careful checking of the analyses for chemical balance and eliminating the analyses that do not balance properly. Interpretation of the chemical data should be made only after assuring that these monitoring problems have been taken into ac

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03398.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTGround‐water chemical quality in alluvial valleys can be stratified, which can cause well‐water quality to vary with pumping time, especially after a pump shutdown of several hours. These changes in chemical quality could have public health implications for automatically controlled high‐capacity municipal water wells that pump directly into the distribution mains.For a large number of municipal wells, the shapes of the curves for the change‐in‐specific electrical conductivity and the NO3‐N content of well water during the first 96 minutes of constant rate pumping are reported after a 24‐hour shutdown as compared with “steady‐state” quality. The variables recovery‐transmissivity, well specific capacity, type of well construction, and equivalent specific yield of aquifer computed from driller's logs of the bore holes were considered in the analysis.The results showed that well‐water quality vs. time curves vary in shape and are related mainly to the well depth and the depth to the perforations. The “steady‐state” specific electrical conductivity and NO3‐N values were significantly correlated to each other and inversely to recovery‐transmissivity and equivalent specific yield. The specific capacity of wells was related to the recovery‐transmissivi

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03399.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTLinear regression can be applied to multirate pumping test data from a single pumped well to estimate the constants of the equation . An equation has been derived which enables the values of Anat various times to be used to estimate the transmissivity of the aquifer adjacent to the pumped well with due allowance for well loss. An extension of method enables estimation of the order of the storage coefficient.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03400.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTThe High Plains region of mid‐America depends on ground water to a huge extent. A review of three States‐Texas, Colorado and Oklahoma—shows a disparity in ground‐water management in the region. Texas landowners own the ground water as a property right and the emphasis is on local management districts to control ground‐water use. Colorado, in contrast, has State control of ground water and regulation by permit from the State Engineer. Oklahoma is unique in tightly regulating ground water through limitations on pumpage, while still adhering to ownership by the individual landowner.In spite of these differences, six of the High Plains States have united in a joint effort to study the ground water in the Ogallala. A $6 million study funded by EDA will evaluate the economic impacts of ground‐water mining and determine future water resources management in

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03401.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY