ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02942.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTVertical shafts are roughly cylindrical voids in carbonate rocks. They range in diameter from inches to tens of feet and in height from inches to hundreds of feet. They are produced by vertically descending ground water from perched ground‐water reservoirs or surface water. These features are common throughout the Interior Lowlands and Appalachian Plateaus Provinces. Vertical shafts form the headwater termini of complex drainage networks that aggregate the waters into master drains which carry the water to big springs. The drains evolve through time as base level is lowered but retain a dendritic pattern. Shafts are very short lived and occur only near the edge of the clastic caprock in the study area in south central Kentucky. Shafts are formed by free flowing sheets or films of vadose water streaming down the walls in supercritical flow. These waters are undersaturated with respect to calcite at both top and bottom of the shaft, although there is a measurable uptake of CaCO3as the water traverses the shaft walls. The shafts act as aeration chambers, and there is much loss of carbon dioxide from the ground water during movement through this segment of the underground rout

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02943.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTGamma logs, by revealing differences in the radiation intensity of unconsolidated sediments, can provide important information on the depth and sequence of beds penetrated by a cased well. In some instances the log of a well drilled into a sand and gravel aquifer can indicate the interval, or intervals, most favorable for screening. Changes in logs made before and after a well is screened and developed can show zones in the screened interval where most development occurred, and provide valuable clues as to the overall effectiveness of development.Although little used at present, gamma logging holds promise of becoming an important tool in hydrologic studies and in the well construction industry. More testing and possibly standardization of equipment is currently needed, along with experimentation in logging techniques, to improve the method. Field correlation between logs and drilling samples are necessary to improve the accuracy of log interpretation.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02944.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTA new digital‐computer modeling technique uses response curves for discrete regions of a stream‐aquifer system to compute the percentage of applied irrigation water and precipitation that recharges the ground‐water reservoir. The hydrologic system modeled is a part of the Arkansas River valley in southeastern Colorado. A 150‐mile reach of the valley (Pueblo to the State line) was divided into seven smaller reaches. Streamflow, irrigation water applied from canals, ground‐water withdrawal by wells, and precipitation data collected during 1964‐68 were considered. A wide range of assumed values of recharge from applied irrigation water and precipitation were simulated by the model. The differences between computed and measured changes in ground‐water storage were extremely sensitive to the programmed recharge value. Convergence of computed and measured change in ground‐water storage values was obtained for most reaches when 20 to 30 percent of the applied irrigation water and precipitation was computed as recharge

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02945.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTGround‐water irrigation has developed rapidly in the High Plains region of the United States, especially in Texas since the 1930's and more recently in western Kansas. Although most land sales transactions do not show the water value separate from the dry land value, the availability of ground water has greatly affected land values. This study measures this effect by two methods for an area of southwestern Kansas where ground‐water irrigation has become important.The purchasers of all farm land sold in the selected area between 1962‐67 were surveyed to obtain information on sale price and numerous factors which it was thought might have a bearing on the land value. One method of measuring the effect of ground water on land value involved matching a number of tracts not known to have available ground water for irrigation with an equal number having ground water. Since other factors were matched as closely as possible, the differences in land value were attributed to water. The second method was multiple regression in which total tract land value and land value per acre for some 160 tracts were related to several factors–soil and topographic conditions, tract size, availability of ground water for irrigation, nearness to elevator, mineral rights, and wheat allotment. Both methods produced approximately the same results–for the period studied the availability of ground water for irrigation contributed $95 to $100 per acre to the value of

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02946.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

ABSTRACTIn the Rothschild area, Wisconsin, most water wells are completed in glacial deposits. When glacial deposits are unsaturated or thin, wells are completed in fractured crystalline rocks of Pre‐Cambrian age. Specific capacity data from 56 wells tapping these fractured rocks reveal:1Yields and specific capacity are generally small, with a median specific capacity of log 0.17 gpm/ft and a mean value of log 0.10 gpm/ft.2Wells which are close together may have substantially different specific capacities.3The occurrence of saturated sand and gravel above the crystalline rocks has no obvious influence on yield or specific capacity.4Specific capacities of wells seem to be inversely proportional to (a) thickness of rocks penetrated below the water table, (b) depth of the wells below the water table, and (c) depth of the wells below the land surface.Assuming that specific capacities of wells are related to the number of contributing fractures penetrated and that the number of fractures diminishes linearly with depth, the following relation is derived:where Sc= specific capacity, Q = discharge, s = drawdown, B = a constant, b = fracture frequency at the land surface, z = depth, and E = maximum depth of fracturing. In the Rothschild area, E = 100 feet.In exploring for ground water in a fractured rock, the problem is to find the area of maximum b. If sound scientific methods are not available, then exploration will consist of drilling wells at random until a satisfactory well is completed. However, because wells achieve 60 to 80 percent of their yield in the first 20 feet below the water table, test wells should be pump tested when they have reached a depth of about 20 feet below the water table. Unsuccessful wells need not be drilled to completio

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02947.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02948.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1972.tb02949.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY