ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03467.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThis paper presents a systematic method for approximating hydraulic head gradients from randomly located hydraulic head values. The locations of these head values are connected by straight lines to form a network of triangles. Over each triangle, a plane surface is used to approximate the head values; the gradient of this plane is then taken as the hydraulic gradient. Given values of porosity and hydraulic conductivity, the fluid velocity can be calculated from Darcy's Law.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03468.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTA two‐year ground‐water monitoring program at three upland dredge disposal sites in the United States was conducted to determine whether the sites were contributing to ground‐water degradation. Facilities were located at Grand Haven, Michigan, Sayreville, New Jersey, and Mobile, Alabama. Leachate samples were collected from vacuum/pressure lysimeters and ground‐water wells. Ground‐water wells were situated directly under the fill, downgradient, and in an area representative of indigeneous ground‐water quality. Analyses of 27 parameters from 10 sampling periods indicated that calcium and manganese represent major water quality problems due to their contribution to water hardness. Of the trace metals, manganese and iron were found to exceed recommended EPA drinking‐water quality standards at all sites. Levels of potassium, total organic carbon (TOC), chloride, sodium, calcium, alkalinity, and magnesium appear to affect local ground‐water quality. Possible controlling mechanisms for observed leachate concentrations for these parameters include absorption, adsorption, ion exchange complexation, dilution and biol

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03469.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe formation of ground‐water mounds in response to recharge from ponds has been described earlier by equations that have been developed for infinite aquifers. In this paper, an equation for the formation of ground‐water mounds on recharge from a rectangular area to a finite aquifer was derived. The validity of the equation was tested by comparison with field data of recharge from square ponds. The solution derived here appears to describe the actual field response of water table to recharge better than the equation derived for infinite aquif

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03470.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTMarquardt algorithm has been used for estimating aquifer parameters from pump test data in nonleaky and leaky aquifers. It emerges from the study that in spite of poor initial estimates, the convergence is quick; and the residual square error, for the difference between the observed drawdowns and those calculated from parameters estimated using Marquardt algorithm and the known methods, is minimum in the case of Marquardt estimates.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03471.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTIn considering reversible sorption processes in ground‐water flow systems, it is important to determine whether the ground water is in steady‐state or dynamic chemical evolution. In steady‐state chemical evolution, the sorbed site populations at any point along the flow path are in equilibrium with the way in which ground water will evolve chemically due to mineral dissolution/precipitation, redox reactions, etc., during flow when it reaches this point. In dynamic chemical evolution it is not. In the steady‐state case, a location in the flow system can be characterized by a constant distribution coefficient over time for an ionic species involved in reversible sorption reactions. In the dynamic case, the distribution coefficient can be expected to vary at a location in a flow system over time. Subsurface contaminant migration problems which confront hydrogeologists invariably are of the dynamic chemical evolution type and the notion of a constant distribution coefficient or Kdto describe reversible sorption processes cannot be ente

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03472.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe geochemistry of a very permeable ground‐water system containing calcium sulfate was studied to determine the present rate of dissolution. An estimate was made of the chemical composition of water recharging the system and the difference between that estimate and the composition of the ground water in the system was used to determine the minimum amount of calcium sulfate being dissolved under existing hydrologic conditions. This result was used, with published data on rates of calcium‐sulfate dissolution, to determine the effective surface area involved in solution processes. Results indicate that flow in this system is through large solution openings, which are growing larger at a rate of a few tens of millimeters per y

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03473.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTDue to inexperience on the part of those assigned to purchase computer facilities for water resource tasks, a poor or unacceptable choice of equipment is often made. The political realities of introducing new computing equipment into a firm which has several departments which will vie for the use of that equipment must be faced.The size, complexity, and capabilities of the machine to be purchased as well as the software and personnel involved must be considered carefully in relation to the specific tasks at hand. The bidding process, demonstrations, and reference materials offer some assistance in deciding among the often confusing array of systems available on the market.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03474.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTA worldwide overview of structural geologic settings indicates that the homoclinal flank is one of the most widespread and common of hydrogeologic systems. The geomorphic conditions on the structural basin flanks correlate with distinctive ground‐water flow patterns.Relatively undisturbed coastal plain formations and all other sedimentary rocks that are arched or warped into marginal basins are flanked at the land surface by dynamic hydrologie systems. Their aquifers, on a local scale considered to be horizontal, extend into regional tilted and beveled systems. Dips of strata that are only slightly greater than the gross slope of the land surface, but in the same direction, are prominent and produce exposures of alternating permeable and less permeable beveled formations in elongated regional bands. Differential erosion has led to cuesta landscapes in varying degrees. On these step‐like plateaus, subsequent and consequent streams have distinctive streamflow characteristics.One common type of hydrologic system is that dominated by consequent streams flowing down the structural basin, generally through reentrants in scarps. These streams capture much ground‐water runoff at the lowest exposed point in the aquifer (at the apex of the V that the stream makes with an overlying aquitard). The discharging ground water forms a natural cone of depression in the aquifer, representing a chief core of the ground‐water circulation system. An example is the large cone of depression in a Cretaceous sand aquifer in the Savannah River valley 15 to 25 kilometers south of Augusta, Georgia.Graphic modeling of hydrogeologic systems in homoclinal flanks explains the uneven distribution of ground‐water discharge. Stretches of each stream can be classified readily according to the degree of ground‐water discharge on a homoc

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03475.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTEnjebi Island on Enewetak Atoll has been the site of extensive hydrological, geological and geophysical studies. Tidal lag, tidal efficiency and water levels have been measured in 24 wells ranging in depth from one m to 90 m (3–290 ft). Hydraulic conductivity has been measured both on laboratory samples and by aquifer testing in the field. Theoretical ground‐water tidal responses have been calculated using a model based on horizontal propagation of tidal signals. Comparison of field observations and model results indicates that the observed results are not consistent with horizontal tidal propagation and that the hydraulics of the system are probably controlled by vertical coupling between the unconsolidated surface aquifer and an underlying aquifer of more permeable limestone. Results from other islands of Enewetak, Bikini and Kwajelein Atolls are comparable, and suggest that vertical transport between layered aquifers is an important feature of atoll ground‐water hydrology at least throughout the northern Marshall Is

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03476.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY