ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03324.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTData from over 800 well samples collected and analyzed during a study of ground‐water quality in Sussex County, Delaware revealed that the water‐table aquifer contains excessively high concentrations of nitrate in several areas. Over 20 percent of the wells sampled contained concentrations that exceeded 45 milligrams per liter (mg/l), and in many areas, over 50 percent of the wells sampled exceeded 45 mg/l.Sussex County is part of the Atlantic Coastal Plain Province, geologically consisting of a series of unconsolidated sands, gravels, silts, and clays that contain extensive ground‐water reserves of generally high quality. On the basis of iron and nitrate concentrations, two major areas of differing water quality were delineated: one in which the ground water contained variable concentrations of nitrate with low concentrations of iron (2.0 mg/l) and little detectable nitrate.Nitrate concentrations ranged from zero to 224 mg/l; average and median values determined for the area of nitrate occurrence were 33.9 mg/l and 25 mg/l respectively. Treatment of the nitrate data allowed depicting of 19 areas of possible excessive nitrate contamination. Nitrate occurrences were closely related to land use, soil permeability, water‐table depths and aquifer chemistry. The greatest incidence of high nitrate concentrations was associated with confined feeding operations. Other nitrate sources are septic tank effluent, natural and chemical fertilizers, foliage in forests, and precip

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03325.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTRecent advances in the automatic inversion of vertical electrical sounding data offer the opportunity to describe the relationship of the resistivity of a granular aquifer to its hydraulic conductivity. This type of relationship, together with aquifer thickness, can be used to determine the transmissivity of the aquifer.Vertical electrical soundings and pump‐test data along the axis of a glacial outwash aquifer in central Illinois have indicated an inverse relationship between aquifer resistivity and hydraulic conductivity. This relationship has been attributed to differences in sorting of the outwash sediments. But studies of granular aquifers deposited in other geologic environments are needed before meaningful generalizations can be mad

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03326.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTRapid fissure flow has been recognised as an important factor in understanding the hydraulic behaviour of the Lincolnshire Limestone aquifer of eastern England. A study of the hydrogeology of a Lincolnshire Limestone spring‐fed catchment enables three zones of discharge to be defined, based on their relative elevation along the valley floor. Comparison of the discharge characteristics of each zone reveals the existence of rapid ground‐water flow associated with a discrete fissure system. Comparison of spring discharges and ground‐water storage during a period of “high,”“low” and “typical” recharge enables a conceptual flow model of the aquifer to be constructed. A two‐layered model is proposed, in which the secondary zone (upper unit) is characterised by higher transmissivity and lower storativity than the primary zone (lower unit). In addition, there is evidence of a rapid increase in transmissivity with water‐table elevation in the secondary zone. The areal distribution of the secondary zone is associated with a net work dry valleys. The spatial distribution of the two zones is explained by geological structure, lithological variations and the post‐glacial history of the area. A two‐layered model is developed with these concepts in mind in order to simulate the spring discharges. Once proven, the model can be integreated with the regional hydrogeology and incorporated into existing digi

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03327.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTThis paper examines the situation when, due to heavy rainfall, rapid transfer of water occurs in the upper highly permeable region of an unconfined aquifer. The conventional modelling approach of a single transmissivity, which either remains constant or increases with the saturated depth, is shown to be unsatisfactory. Instead it is necessary to consider the aquifer as consisting of two systems with flow always occurring in the primary system but only entering the secondary system during periods of high recharge. This is necessary because the velocities in the different regions of the aquifer are of significantly different magnitudes.The Lincolnshire Limestone aquifer in England is used as an illustrative example. Initially a one‐dimensional approximation to the aquifer is considered so that the different features of the flow mechanism can be examined in detail. The method of dividing the recharge between the primary and secondary systems is shown to be of great importance. Then a preliminary two‐dimensional model of the whole region is considered. The model response is shown to be of the same form as that observed in the field and described in greater detail by Smith (19

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03328.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTMathematical models of ground‐water aquifers with complex geologic and hydrologic factors have been used effectively since 1960 in the world. In these models first the past hydrogeological conditions are simulated, then it is possible to impose on the model the future conditions by increasing, redistributed pumping, artificial recharging or many other factors which may change the existing hydro‐geological conditions.Different numerical methods such as finite difference, finite element and dynamic programming are used in mathematical simulation of the aquifers.The study of different aquifers in Iran by classical methods has been started systematically since 1962, and during this period more than 200 aquifers (550,000 km2or 212,000 sq mi) are studied in reconnaissance phase and about 80 aquifers (250,000 km2or 96,500 sq mi) in semi‐detailed phase. In 1967 the mathematical model technique was introduced to ground‐water researchers of Iran. Actually 39 aquifers are studied by 2‐ or 3‐dimensional flow models covering nearly 40,000 km2(15,440 sq mi) of Iranian aquifers. In these studies finite difference methods are largely used, and only a few aquifers are studied by dynamic programming, but the finite element has never been u

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03329.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTLubbock is located in the center of the semiarid High Plains of Texas. Due to a shortage of adequate water‐based recreational facilities in the region, the City Planning Department developed a scheme for converting an eight‐mile intracity canyon into a linear park containing a series of small recreational lakes. Funds amounting to over 11 million dollars were committed to the project by a local bond issue and various governmental organizations.The proposed lake makeup water is unique. Never before has a serious attempt been made to develop recreational lakes utilizing urban runoff and twice‐used reclaimed municipal waste water as the sole source of supply. The majority of the makeup water will be obtained from wells on a farm which has received the major portion of Lubbock's secondary treated sewage since 1938 and used it for irrigation purposes.In order to ascertain the suitability of utilizing this reclaimed sewage effluent for recreational purposes, the Texas Tech University Water Resources Center with the aid of an OWRT grant constructed a model system designed to simulate the lake project. Research performed to date includes algal growth potential studies, water quality analyses, bacteriological assays, viral assays, and fish life st

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03330.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.Both irrigated agriculture and areas with dry, hot‐rock formations at relatively small depth are ubiquitous in the western United States. The former produces saline percolation water, while the latter needs water to transfer the heat to the surface to enable exploitation of the geothermal energy. Thus, it seems logical to investigate the possibility of converting irrigation return flow, which often presents an environmental liability, into a useful asset by pumping it into artificially stimulated hot‐rock formations. When brought up as hot fluid, the water can then be used for generating power, producing fresh water, and/or space heating. The paper summarizes quantity and quality of irrigation return flow, various types of geothermal systems, and quantities of power and fresh water that can be derived from steam or hot wa

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03331.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.An evaluation was made of the usefulness of the gamma‐ray logger in delineating glacial‐drift and bedrock stratigraphy in southwestern Ohio. The logger was useful in delineating gross stratigraphic units in a glacial outwash aquifer. The gamma log also provided a clearer indication of the clay content of sand and gravel units than did the driller's log.On the uplands, away from the valleys filled with glacial outwash, the logger could not be used to locate the thin, poorly‐sorted, interstadial sand and gravel deposits between thicker till sheets. It could, however, be used to distinguish formational contacts in the upper Cincinnatian S

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03332.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1979.tb03333.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY