ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03377.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTGround‐water modeling is a tool that can help analyze many ground‐water problems. Models are useful for reconnaissance studies preceding field investigations, for interpretive studies following the field program, and for predictive studies to estimate future field behavior. In addition to these applications, models are useful for studying various types of flow behavior by examining hypothetical aquifer problems. Before attempting such studies, however, one must be familiar with ground‐water modeling concepts, model usage, and modeling limita

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03378.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTAn investigation of waste‐migration patterns from a septic system indicates that complex patterns result from minor variations in regolith adsorptive capacity and texture, local hydrology, and possibly soil microbiology. The existence of multichemical, bifurcating plumes suggest that monitor wells arranged up and downgradient and capable of multilevel sampling are essential to adequately delineate contaminant migration in ground water. The data also indicate that sampling for a single constituent could yield misleading information about the nature and distribution of other ground‐water contaminants. The ability for chemical removal by the regolith is in direct response to minor variations in silt‐ and clay‐sized particle content and corresponds to Langmuir adsorption isotherms. Silt‐ and clay‐sized particles are dominantly organic in origin. Minor iron and aluminum hydroxyoxides and clays are present.Substrate samples, when collected at regular intervals and analyzed for adsorbed constituents and textural variability, provide an integrated picture of the distribution of waste chemicals through time. Such samples also provide insight into the mechanics of plume configuration and flow characteristics within the regolith. The study shows that regolith adsorption data are essential to the determination of life expectancy of the regolith as a contaminant treat

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03379.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTProgrammable calculator programs have been previously given for the calculation of head or pressure change resulting from the pumping from or injection into wells completely penetrating a fully confined aquifer. Programs are documented and example calculations shown here for wells completely penetrating a semiconfined aquifer. The programs are for the TI 59 card programmable calculator.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03380.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTPolynomial approximations have been developed for the infinite series embodied in the Theis equation. These have the following advantages when programmed for use on computers or hand calculators: (1) they are easy to program; (2) they are computationally efficient; and (3) they eliminate round‐off error

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03381.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTThe expressionis a handy tool for predicting aquifer parameters using all the drawdown and recovery data obtained during step‐drawdown tests or periods of cyclic or intermittent pumping.For inefficient wells the expressionfits pumping wells better. The data from conventional step‐drawdown tests of pumping wells can be used to obtain T, C, and y. If the data fail to fit the ideal, they may be used to interpret local hydrologic conditi

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03382.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA numerical model based on a finite difference technique has been developed to analyse and solve the problem of an unconfined coastal aquifer of infinite extent with free surface and interface along with the width of outflow face as unknown boundaries. The problem has been formulated in a complex potential plane and a five‐point operator of a finite difference scheme has been used to reduce the governing flow equation into a set of linear algebraic equations which is solved by the Gauss‐Seidel iterative method with an over‐relaxation factor. Results of the analysis provide a generalised dimensionless plot for assessing the fresh‐water flow to the sea from the known field information of aquifer characteristics and water‐table head landward from the

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03383.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTThe Fort Payne Formation of Early Mississippian (Osagean) age crops out over extensive areas of central Tennessee, south‐central Kentucky, and northern Alabama. Specific formation lithologies are known to have been modified locally through weathering into an artesian aquifer along the Eastern Highland Rim of central Tennessee. The shallow aquifer can be divided into two parts; uppermost is a highly permeable chert gravel zone that is in hydraulic communication with a lower zone of interconnected solution cavities within bedrock. The gravel, at depths as great as 24.4 m (80 ft), fines upward into the clay‐sized chert of the upper confining bed. The lower confining bed is the Chattanooga Shale of Late Devonian to Early Mississippian age.Field and petrographic studies of the Fort Payne Formation indicate that the aquifer has developed near the base of the unit. The chert gravel portion of the aquifer has developed from silicified dolowackestones of the Beaver Creek Limestone Member and from interbedded Fort Payne dolostones. The lower portion of the aquifer occurs within preferentially weathered, silicified and non‐silicified dolosilt

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03384.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA comparison of the concentrations of nitrate in three public supply borehole sources which abstract water from the Chalk in a relatively local area, led to a more detailed study of the possible causes of high nitrate values at one of the sources and the geological and recharge characteristics of all three.The local catchment area of the high nitrate source is actively fertilized, both by sludge spreading and the application of artificial fertilizers. The catchment areas of the other two ground‐water sources are not subject to the same intensive agricultural activity. It is suggested the differences in water quality between the three supplies are related to the variations in land use and the local hydrogeology.The study makes it clear that due to local influences each source may have a unique hydrogeochemical character irrespective of being located in the same regional geological catchment area.More detailed investigations on the origins of the nitrate in the abstracted ground waters are planned as a follow‐up to this initial st

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03385.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACTA survey of the requirements of State regulatory agencies responsible for monitoring ground‐water quality at waste disposal sites was conducted in order to gain a concise profile of monitoring practices across the country, and also to provide the basis for a monitoring manual to serve as technical background and guidance for the citizens of Minnesota. The survey considered a variety of topics including the regulatory framework for requiring monitoring, chemical parameters analyzed, recommended methods of monitoring well construction and sample collection, laboratory quality control, data interpretation, and post‐operational monitoring requirements.The survey showed that most State monitoring programs are in their infancy. Many States, however, are beginning to devote serious effort and manpower commitments to the development of monitoring programs, although there is considerable divergence of opinion regarding how these programs should be conducted. Federal legislation establishing minimum performance criteria instead of detailed operating requirements for waste disposal sites will increase the need for sound water monitoring programs at these sites in the fut

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1980.tb03386.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY