ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03069.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTAn important part of every investigation of ground‐water pollution is to locate and define the extent of the contaminated body of ground water. The usual method for accomplishing this is to install and sample numerous test wells, a costly and time‐consuming procedure. A much faster and less costly method, which has proven to give accurate results, is the earth resistivity survey. Because earth resistivity is inversely proportional to ground‐water conductivity, the location of ground water that has been contaminated by a relatively high concentration of conductive industrial wastes, for example, may be quickly and accurately traced.In order for the resistivity method to give useful results, resistivity contrasts must exist in the subsurface. For example, if the contaminant does not have a significantly greater conductivity than the natural ground water, or if the ground water is naturally highly conductive itself, a large enough resistivity contrast may not exist, and the method may not work. In addition, if depth to water is too great, the thickness of the unsaturated sediments can mask any contrasts between contaminated and natural ground water. The geologic environment must be relatively uniform so that the resistivity values and profiles can be compared with one another. At most industrial plant sites and landfills, these conditions are met. That is, the area of investigation is usually limited to a few hundred acres, where the geology and depth to water tend to be uniform.Four case histories of industrial and landfill sites are discussed in this paper. The areas underlain by the contaminated ground‐water bodies ranged from 25 to 100 acres. The depths to the contaminated water were relatively shallow, ranging from 5 to about 60 feet below land surface. In three of the cases, the results of the earth resistivity studies, which were verified by installing test wells in and around the area being investigated, proved to be remarkably accurate. In the fourth study, the conditions mentioned were not met, and the survey was unsuc

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03070.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTWoodward‐Clyde Consultants was retained to investigate a ground‐water contamination problem caused by disposal of chromium‐laden process water into an unlined lagoon in the Coastal Plain sediments of southern New Jersey. During the course of the investigation, a technique for sampling of formation water at specific horizons during drilling was developed. This technique consists of the following procedure: (1) drilling a borehole to the base of a sampling horizon; (2) lowering a wire‐wound well screen and riser pipe to the bottom of the borehole and gravel‐packing the screen; (3) pumping the borehole well until the discharge is clear of drilling fluid; and (4) pumping at least 100 gallons of formation water before collecting the sample and performing field water quality tests.Analysis of water samples withdrawn from a cluster of five wells, drilled to and screened at specific depths of 20 to 100 feet, verified that the special drilling and sampling technique developed was a valid method to obtain representative, in‐situ water samples from specific horizons. This sampling procedure was then used to substantiate surface earth‐resistivity survey data and provide important information on the vertical distribution of the contaminant within the aquifer. The delineation of the contaminant within the aquifer was an important part of Woodward‐Clyde Consultants'responsibility to evaluate the extent and magnitude of ground‐water contamination at the plant site and design an economically and technically feasible system for the removal and treatment of the contaminated ground water and eventual recover

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03071.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTFaulty disposal of oil field brine through an “evaporation” pit and later through a faulty disposal well resulted in the contamination of one square mile of an alluvial aquifer in southwestern Arkansas. The physical parameters of the contamination are defined, and some of the chemical changes that occur as the brine moves through the aquifer are explained.In addition, alternate methods of aquifer rehabilitation are explored, and the costs of rehabilitation are compared with potential benefits. It is concluded that rehabilitation is not now economically justif

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03072.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTThe Lake George Village sewage treatment plant has been discharging trickling filter effluent onto natural delta sand beds for a period of 35 years. The applied sewage apparently appears near the banks of West Brook approximately 600 m (2000 ft) from the lower sand beds. Wells have been placed between the recharge beds and the appearance of the seepage at West Brook. The quality of the water in the wells has been evaluated over the period of slightly over one year.The ground water appears to be aerobic at all times indicating that the oxygen demand of the applied effluent has been adequately reduced before it reaches the ground water. This should afford adequate and proper tertiary treatment for the applied effluent.The phosphorus concentration was significantly reduced at the first well downstream (ground water) approximately 150 m (500 ft) from the sand beds. The phosphorus in well 2 approximately 600 m (2000 ft) from the lower sand beds reached a high value of 150 μg/l during the late fall but was less than 100 μg/l during the rest of the year.Some of the nitrogen in the applied effluent was apparently oxidized to nitrate which was very little removed by the sand system. The highest nitrate concentration found was 14 mg N/l in well 3C during the Spring, whereas well 3A had almost consistently the lowest concentration of nitrat

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03073.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTThe theoretical shape of a zone of contaminated ground water (henceforth called an enclave) can be predicted from a knowledge of the three‐dimensional, ground‐water flow pattern. The reasoning in LeGrand (1965) and Sendlein and Palmquist (1973) suggests that the horizontal shape of the enclave is a flame‐like plume extending from the source, parallel to the ground‐water flow lines, in a downflow direction. According to LeGrand, the ultimate size of the enclave will depend upon the relative rates of decay, diffusion, dilution and absorption of the contaminants. Similar reasoning suggests that, in vertical section, the boundaries of the enclave will follow the ground‐water flow lines between contamination source and ground‐water discharge site. This reasoning suggests that the three‐dimensional shape of an enclave is that of a tongue‐like lobe, the length, width and depth of which increases with increasing distance from and increasing height above the discharge site.In Iowa, the hydrology of refuse sites emplaced in alluvium has been analyzed to determine the size and shape of the associated enclaves. The refuse sites range in size from 13 to 117 acres (5.25 to 47.3 hectares), in age from 9 to 40 years, and in topographic position from floodplain adjacent to river to terrace. The ground‐water quality and water‐table elevations were determined from multiple nests of piezometers (from depths of 15 to 45 feet) (4.7 to 13.6 meters) around the refuse sites. The surficial geology of the sites was established from both borehole and geophysical data.The Iowa data suggests that the enclave in alluvium is plume‐shaped with the long axis parallel to the ground‐water flow lines and extending from the refuse site to the nearest stream. The SO4enclave at the Ames site, for example, is over 7000 feet (2121 meters) long, 4500 feet (1362 meters) wide and extends to a maximum depth of 60 feet (18.2 meters). The highest SO4concentrations are along the axis of the enclave at a depth of 30 feet (9.09 meters). The concentrations decrease with distance along the axis, laterally away from the axis and vertically away from the axis, such that the enclave is entirely surrounded by uncontaminated ground water except at the source. Analysis of the variation in water quality data with time indicates that most of the enclaves are not increasing in size but have achieved their maximum size and are in a steady‐state equilibrium condition.The Iowa studies indicate that the size and shape of the contamination enclave resulting from refuse disposal sites can be predicted from the initial geohydrologic conditions and that it may become possible in the near future to estimate the concentrations within the enclave at any point in time and space. These possibilities open the way toward a strategy of minimizing potential contamination of aquifers through selective refuse site placement on the floodplain. The Iowa data indicates that floodplain sites may be desirable for disposal sites because of the predictability of enclave shape within alluvium, the tendency for floodplains to be ground‐water discharge sites and the low concentrations of the leachate produced in a high ground‐water flow environment.The results of this study strongly indicate that any monitoring system around a refuse disposal site be judiciously placed. Not only must the location of the wells be considered but also the depth of wells. To monitor maximum leachate concentrations, wells must be located in a downflow direction and along the axis of the enclave. Likewise, wells which are too shallow or too deep will miss the core of an enclave and yield leachate samples with low concentrations. It thus becomes necessary to estimate the size and shape of the enclave prior to establi

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03074.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTStudies at three solid‐waste disposal sites in the Anchorage area suggest that differences in local geohydrologic conditions influence ground‐water quality. A leachate was detected in ground water within and beneath two sites where the water table is very near land surface and refuse is deposited either at or below the water table in some parts of the filled areas. No leachate was detected in ground water beneath a third site where waste disposal is well above the local water ta

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03075.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTIn cooperation with the city of Indianapolis, the U.S. Geological Survey undertook a study to determine the nature and extent of water pollution resulting from the operation of seven landfills in or near the city. To accomplish this, 10 to 36 observation wells, ranging from 14 to 170 feet (4 to 52 metres) deep, were installed in and around each landfill. The wells were installed variously by auger, rotary, and air‐rotary methods; the mud for the rotary drilling was natural mud, bentonite and(or) an organic polymer. The wells were constructed of 2‐inch (5‐centimetre) PVC casing, and ended either in slotted casing or PVC “wire‐wrapped” screen. After the wells were completed and developed, water samples were collected from selected wells for detailed chemical analysis. This type of analysis will be repeated yearly on selected wells. Every month the water levels are measured and field determination of four chemical and physical water parameters are made. Water samples have been collected using a bailer, a centrifugal pump, and a gas‐driven pump.Based on the experiences so far, the following are considerations in planning future studies:1Keep the objectives of the study well in mind in planning the methods to be used and the financing.2Black iron pipe is suitable well casing except when careful analyses are needed for research projects, for sampling concentrated leachate, or where rapid corrosion can be expected.3Use of 4‐inch (10‐centimetre) casing may provide more options than 2‐inch (5‐centimetre) casing as to method of collecting water samples, and may be easier to install and develop.4A power auger is preferable for drilling and installing small‐diameter wells in refuse.5A drilling mud made with an organic polymer is effective, particularly if 2‐inch (5‐centimetre) casing is used, but provides a medium for bacterial growth.6When the water level is too deep for a centrifugal pump to function in a 2‐inch (5‐centimetre) well, a bailer is more efficient and fairly contaminant‐free.7Once good control on water quality is obtained, field determination of selected parameters is sufficient to fo

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03076.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTMore than 10 billion gallons (38 × 106m3) of acid industrial liquid waste has been injected in about 11 years under high pressure into a saline‐water‐filled part of a limestone aquifer of low transmissivity between 1,400 and 1,700 feet (430 and 520 m) below land surface near Pensacola, Florida. A similar waste disposal system is planned for the same zone at a site about 8.5 miles (13.7 km) to the east. The injection zone is the lower limestone of the Floridan aquifer. The lower limestone is overlain by a confining layer of plastic clay about 220 feet (67 m) thick at the active injection site and underlain by another confining layer of shale and clay. The upper confining layer is overlain by the upper limestone of the Floridan aquifer.The active injection system consists of two injection wells about a quarter of a mile (0.4 km) apart and three monitor wells. Two of the monitor wells (deep monitors) are used to observe hydraulic and geochemical effects of waste injection in the injection zone at locations about 1.5 miles (2.4 km) south and 1.9 miles (3.1 km) north of the center of the injection site. The third well (shallow monitor), used to observe any effects in the upper limestone, is about 100 feet (30 m) from one of the injection wells. Since 1972 the injection zone has also been monitored at a test well at the planned new injection site. Three more monitor wells in the injection zone were activated in early 1974 at sites 17 miles (27 km) northeast, 22 miles (35 km) east and 33 miles (53 km) northeast of the injection site. The six deep monitors provide a system for evaluating the regional effects of injecting wastes. No change in pressure or water quality due to injection was, by mid‐1974, evident in the upper limestone at the injection site, but static pressures in the lower limestone at the site had increased 8 fold since injection began in 1963. Chemical analyses indicated probable arrival of the diluted waste at the south monitor well in 1973. By mid‐1974 waste evidently had not reached the north monitor well.Calculations indicate that by mid‐1974 pressure effects from waste injection extended radially more than 40 miles (64 km) from the injection site. By mid‐1974 pressure effects of injection were evident from water‐level measurements made at the five deep monitor wells nearest the active injection site. No effects were recognized at the well 33 miles (53 km) away. Less than 20 miles (32 km) northeast of the active injection site, the lower limestone contains fresh water. Changes in the pressure regime due to injection indicate a tendency for northeastward movement of the fresh‐water/salt‐water interface in t

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03077.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

ABSTRACTDoor County, a recreational and fruit‐growing area bordering Lake Michigan in northeastern Wisconsin, has had a long history of ground‐water contamination from surface and near‐surface sources. Contamination is most severe in late summer when the influx of tourists and fruit‐canning operations create additional wastes.Thin soil cover and well‐fractured dolomitic bedrock give easy entry to ground‐water contaminants throughout large parts of Door County. Many contaminants enter the dolomite by surface or near‐surface seepage. There is little attenuation of contamination concentrations in the well‐jointed dolomite, and contaminants may travel long distances underground in a relatively short time. The major source of ground‐water contamination is bacterial, from individual waste‐disposal systems, agricultural, industrial, and municipal sources. Contamination is in zones that originate from point sources and move in the direction of ground‐water flow, either naturally or as induced by pumping wells. The contaminated areas include only a small percentage of the total ground‐water system and are separated by large areas of ground water free of contamination. Tests based on indicator bacteria suggest that the periods of highest contamination potential occur during or immediately following rapid ground‐water recharge periods. Increasing the depth of casing and pressure grouting the casing into firm bedrock are two well‐construction procedures that reduce the conta

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1975.tb03078.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY