ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01040.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01041.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTWe propose a new way to correct estimates of solution conductivity for the effects of clay in a rock. The bulk electrical conductivity of a rock is dependent on its porosity, the conductivity of the pore fluid, and its clay content. Archie's law relates the bulk electrical conductivity to the first two factors only. The third factor, clay, enhances a rock's conductivity through surface conduction, and simple application of Archie's law will lead to overestimates of the solution conductivity. The enhancement due to clay can be estimated from measurements of induced polarization, however, and the bulk conductivity of the rock can be corrected. This correction will then lead to a more accurate estimate of the solution conductivity. Both resistivity and induced polarization can be measured by geophysical techniques. Interpretations of geophysical data are inherently nonunique, however, unless wells are correlated with the data. The method proposed here requires calibration with subsurface samples from at least one location. We have tested the method we propose to correct for clay in an area already sampled by monitoring wells. The corrections lead to substantial improvements in the correlation between solution conductivities from wells and from geophysical measurements. We are not proposing replacement of wells with geophysical soundings. Rather, the geophysical measurements, which are obtained at a fraction of the cost of a well, can be used to site wells and minimize the amount of drilling needed.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01042.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTA ground‐water assessment of Sinai, Egypt, was performed by Dames&Moore for the Egyptian Ministry of Development from 1980 to 1983 as a part of the Sinai Development Study. The basic data included existing stratigraphic data from 69 wells and 57 columnar sections, and hydrologic data for 716 water points (wells and springs).Statistical analysis of the data for total dissolved solids (TDS) and for yields from the water points by ground‐water province and by geologic unit showed that the Southern Mountain Province generally has the best quality ground water and the Suez Rift Province the worst. Among all the geologic units, the crystalline rock, the Middle Cretaceous sequence, and the Quaternary deposits yield water of the lowest total dissolved solids. The mean TDS value of ground water from all water points in Sinai for which data were available is 2,800 mg/1. Of all the geologic units, the highest mean yield (200 m3/day, or about 37 gpm) was from Quaternary deposits in the vicinity of El Arish in the north and in the El Qaa plain along the southwest coast.Regional ground‐water flow in the sedimentary aquifers, such as the Lower Cretaceous (and older) sandstone, tends to be strongly influenced by large‐scale folds and faults. In this aquifer, regional flow occurs generally northward and northeastward toward the Arava valley and the Dead Sea in Israel, but another component of flow occurs toward the Gulf of Suez on the weste

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01043.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTSolutes were determined for 26 pore‐water samples extracted from Tertiary and Cretaceous core material from a 1,320‐foot‐deep test borehole at Freehold, New Jersey. The cored materials are sediments that form a multilayered aquifer system of seven aquifers and eight confining units in the New Jersey Coastal Plain. The sediments are of marine origin in the upper 650 feet of the core and primarily nonmarine below 650 feet. Total concentrations of silica and major anions (SO4‐2and Cl‐) and cations (Ca+2, Mg+2, total Fe, Mn+2, Na+, and K+) in the pore‐water samples varied with depth. Three core intervals are defined by water‐ chemistry variations, the environment of deposition (marine or nonmarine), and the degree of alteration (weathered or unweathered) of the units. Calcium, magnesium, sulfate, and total‐ion concentrations were greater in the midcore (unweathered marine) interval than in the upper (weathered marine) and lower (fluviodeltaicsilicate) intervals of the core. Generally, pore‐water chemical types in confining units were distinct from those found in aquifers–particularly in the midcore interval. In this interval, observed variations in pore‐water chemistry in part reflect carbonate dissolution and cation exchange reactions common in Coastal Plain sediments. However, high concentrations of sulfate in unweathered marine sediments indicate novel processes may be important factors influencing pore‐water chemi

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01044.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThe ionic composition of water in the vadose zone of the Salt River Valley in south central Arizona was studied for three different water regimes: desert, irrigated, and flooded by urban runoff. The desert area exhibited high salinity in the top 10 m, probably due to concentration of salts over several years. Below 15 m, the salinity decreased with depth and approached the salinity of the native ground water. For the irrigated area, the chemical composition of the soil water was similar to that of the applied water but concentrations were higher. The irrigation efficiency calculated from the salinities of the irrigation and soil water was 78%.The average NO3‐concentration from five of six sites was 100 mg/l, but was as high as 24,000 mg/l at another. Soil water from the urban runoff site had an electrical conductivity that was about three times less than that from the irrigated site, showing the effect of leaching with rain water. The observed salt distributions in the vadose zone were reasonably correlated to land use at the sites sample

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01045.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTSoluble hydrocarbon and dissolved oxygen (DO) in a shallow aquifer beneath a field site were characterized by sampling ground water at 42 monitoring wells. Results from 10 sampling periods over three years showed a significant reduction in total benzene mass with time in ground water. These reduction and leakage rates from sources were determined from material balance and nonlinear least‐squares analyses. The natural attenuation rate was calculated to be 0.95%/day. Spatial relationships between DO and total benzene, toluene, and xylene (BTX) were shown to be strongly correlated by statistical analyses and solute transport modeling. In addition, laboratory microcosm biodegradation experiments were performed to determine possible threshold limits for aromatic hydrocarbon oxidation under varying levels of dissolved oxygen. The results were remarkably consistent with field data on the presence of high or low levels of BTX and DO in several monitoring well‐water samp

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01046.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTGround‐water protection strategies have been constrained by the limited consideration of varied and new options relevant to particular problems. Consequently, management practices have tended to maintain the status quo regarding legislation and water‐quality standards. To examine the responses to specific issues, we presented an analysis of the problem of nitrate contamination of ground water in the Midwest to a community of experts. Ninety‐seven individuals, through a formal questionnaire, responded to a variety of questions pertaining to the issue. They showed definite preferences in dealing with certain aspects of the problem, although there was significant variability in responses due to such factors as length of ground‐water‐related professional experience and residential status. It was clear that respondents preferred immediate preventive or corrective action in a world of incomplete knowledge over extensive research; were willing to undertake personal action to seek nitrate‐free water rather than wait for official action; and favored local and state level involvement over federal intervention. Findings based on this survey research can be used effectively in the planning of future work to establish actual preferences in communities with serious nitrate contaminati

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01047.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThe coefficient of permeability or hydraulic conductivity is a basic parameter of a granular media. It is difficult to determine the coefficient of permeability because it depends on many factors. According to experiments and analysis, we think the permeability of a granular media results from the unified effect of an external factor—the hydraulic gradient, and internal factors—properties of the granular media itself and the fluid; therefore, the permeability of a granular media can be determined by a sieve analysis and physical characteristics of the fluid. Based on theoretical analysis and experiments, we advance a unified expression to calculate the coefficient of permeability of a granular media. The precision of the formula is up to practical requirements based on inspection of experimental data. The formul

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01048.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

ABSTRACTThis paper describes a technique for estimating gradients of hydraulic head from scattered measurements of head. Gradients of hydraulic head control the flow of ground water in aquifers and their determination is an important part of any ground‐water investigation. A best linear unbiased estimator of hydraulic head is derived which allows direct estimation of head gradients and mean square estimation error. The hydraulic head is broken into continuous and discontinuous components. The discontinuous component, which represents random measurement error and small‐scale variability, is filtered from the measurements. The technique is applied to measurements of head in the Wolfcamp aquifer in northern Te

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1989.tb01049.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY