ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03495.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe development of ground‐water resources in the Bangkok Metropolis over the last decades in an unplanned manner has resulted in a continual decline of the piezometric head in three aquifers underlying the city. One of these three aquifers identified as Nakhon Luang Aquifer provides the major portion of the ground‐water supply and has been considered for analyzing the hydrodynamic behavior under different operating schemes.It is predicted that continuation of the present rate of water withdrawal will result in a severe decline of the piezometric head, and by the year 2000 most of the public supply wells will no longer be in operation due to water level decline below the maximum depth provided for pump installation. Governmental authorities are actively considering the possibilities of increasing supply from surface‐water sources so that the ground‐water use can be phased out. A need to adopt policies to control the private and industrial usage of ground water in order to maintain its future availability is in

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03496.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTWater levels and gradients are a consequence of the nature of geological media and their study helps to define the hydrogeological environment. In this paper, water levels of wells in a typical weathered and fractured granitic environment of Shadnagar Basin, Andhra Pradesh were analyzed. These studies indicate the hydraulic continuity and unity of ground‐water flow systems in weathered and fractured granites contrary to the conclusions of earlier workers. Also, the long‐term behaviour of hydrographs reveals that the basin is not over‐developed and precipitation is the only source of recharge to the ground‐water

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03497.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTIncreased attention is being directed toward the investigation of tight zones in relation to the storage and disposal of hazardous wastes. Shut‐in tests, slug tests, and pressure‐slug tests are being used at the proposed Waste Isolation Pilot Plant site, located in southeastern New Mexico, to evaluate the fluid‐transmitting properties of several zones above the proposed repository zone. Apparatus used to conduct these tests includes a pressure‐transducer system connected to a recording device at the land surface. All three testing methods were used in various combinations to obtain values for the hydraulic properties of the test zones. Multiple testing on the same zone produced similar results. Transmissivities determined by these tests range from 0.00001 to 10 feet squared per day (.000001 to 1 meter squared p

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03498.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTStable and radioactive isotopes (deuterium, tritium,18O,14C) were used as an aid for better understanding the regime of recharge and flow in ground water in the Wadi Feiran basin in the southern Sinai.The annual average precipitation in the Sinai basin is between 80 mm in its upper reaches and 15 mm in the lower regions.In the upper part, underlain by crystalline rocks, ground water was found in shallow and deep fractures as in shallow alluvial deposits. The quality of water in the shallow fractures showed little effect of evaporation in relation to precipitation, which shows that recharge occurs directly and quickly through the open fractures. In the middle part of the basin, water in the riverbed alluvium was found to be recharged mainly by flood water and discharged also through deep fractures. In the lower part of the basin, the ground water was found to flow into the alluvial plain at A‐Tor. Part of it mixes with paleo‐water and emerges as thermal spri

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03499.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTOrganic solvents, including 1,1,1‐trichloroethane at concentrations up to 40,000 ppb, were detected in the Old Bridge aquifer under an industrial plant in South Brunswick Township, New Jersey. A hydrogeologic investigation defined the ground‐water flow system and a plume of contamination which extended, at a concentration of at least 100 ppb, for a distance of about 1000 feet down‐gradient of the plant. A contamination abatement system was designed and installed to prevent this plume from reaching a municipal well located about 2500 feet from the site. The system includes seven extraction wells and a water treatment facility. The locations of the extraction wells and their combined pumping rate were determined in part by a computer simulation of the aquifer, which was subsequently checked by a 20‐day pumping test of the system. The on‐site treatment facility uses two cooling towers in series to air‐strip the volatile organics, and two infiltration ponds to return the treated water to the aquifer. The abatement system has been operating for about 10 months. Ground‐water monitoring results show that the plume is now significantly smaller and less concentrated than before the abatement system was installed. It is projected that in several years the aquifer will be largely d

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03500.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTTwo alternative methods of analyzing the response of large‐diameter wells are considered—the curve matching technique based on analytical solutions and the use of a numerical model. For ideal situations the methods give the same results but for unconfined aquifers where the decrease in saturated depth is significant, the curve matching technique is unreliable. Two particular examples are considered in detail. In a confined aquifer, where the diameter of the dug portion of the well is much larger than the diameter of the hole bored through the confined stratum, the response is found to be particularly sensitive to the ratio of these diameters. In an unconfined aquifer test, the important feature is the reduction in abstraction rate as the well is emptied. For each example, the recovery data is of critical importance in analyzing the te

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03501.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThis paper discusses certain of the reasons for deviations from the classical type curve behaviour during pumping tests. A particular series of pumping tests in a confined limestone aquifer is considered; the tests include a step test, a 3‐day test and a 71‐day test. Using a radial flow numerical model, the influences of transmissivity, storage coefficient altering with radius, a neighbouring baseload borehole and a distant unconfined boundary are each considered. The baseload borehole is shown to have a significant effect on both abstraction and recovery response for the 3‐day test, while both the baseload borehole and the unconfined boundary modify the response for the 71‐d

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03502.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTAspects of a nine‐month characterization of the physical‐chemical dynamics of a dissolved inorganic fertilizer plume in a shallow sand and gravel aquifer are reported. The work was undertaken to establish the extent of ground‐water contamination due to extremely high levels of total ammonia (>2,000 mg L−1) and to provide a basis for remedial action.The results from a numerical solute transport model showed the plume of contaminated ground water persisted at steady‐state conditions within the study site. This conclusion is supported by a comparison of the time of source emplacement (three years) to the calculated requirement of approximately one year for the plume at the field location to achieve a steady‐state configuration. Simulations suggested once the source was removed, about 420 days would be required to naturally flush the contaminant plume from the site.Chemical equilibrium calculations demonstrate that phosphate and carbonate mineral equilibria control calcium solubility in contaminated ground water. The most probable natural sink for ammonia removal from the plume is by the activity of nitrifying microorganisms, presumably well‐acclimated to the extre

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03503.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTWell performance and production life can be enhanced greatly by proper design and operation. Using screen entrance velocity as the only design criteria is not sufficient for describing flow around the well, and in many cases leads to an overly optimistic design. Approach velocity and turbulence (Reynolds Number) are more direct concepts in regard to the factors influencing long‐term well efficiency, and their use as design criteria is strongly encouraged. In addition, sizing of screen slots and filter materials is haphazardly practiced by too many in the ground‐water industry, and requires a renewed awareness.Distribution of flow along the screen, as well as the vast number of aquifer conditions, are also factors to be considered during design. It is here that the judgement and practical experience of the hydrogeologist are most important.The fundamental design criteria are relatively simple to apply, and for the practicing hydrogeologist, the design process is aided by composite graphs. Several such design graphs are given for convenient refere

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1981.tb03504.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY