摘要:

AESTRACT An evaluation of the Maxey‐Eakin method for calculating recharge to ground‐water basins in Nevada was performed. The evaluation consisted of comparing Maxey‐Eakin estimates with independent estimates of recharge, and analyzing the nature of the differences between the groups of estimates. In the comparison with the Maxey‐Eakin estimates, two different groups of independent estimates were used: (1) 40 recharge estimates that were identified from water budgets contained in reports by the Nevada Department of Conservation and Natural Resources and (2) 27 recharge estimates that were identified from previous studies that used models. The results of the comparisons indicate generally good agreement between the Maxey‐Eakin estimates and both groups of independent estimates. To quantify this agreement, an analysis was conducted to estimate the uncertainty in the Maxey‐Eakin method. The analysis produced an upper bound on the standard deviation of the Maxey‐Eakin estimate for a given basin. For the group of 40 water‐budget estimates, the upper bound on the standard deviation for an individual basin is 4,800 acre‐ft/yr, and the corresponding coefficient of variation of the Maxey‐Eakin estimate is no greater than 44 percent. For the group of 27 model estimates, the upper bound on the standard deviation is 4,100 acre‐ft/yr, and the corresponding coefficient of variation is no gr

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03277.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:Due to the spread of Islam in the seventh century the number of pilgrims to the City of Makkah increased sharply, resulting in an acute water shortage. To solve this problem, galleries were built to collect water from the upstream of Wadi Naaman and transfer it to Makkah.Expansion of Makkah and the absence of any mapping of the galleries have resulted in the destruction of a part of the galleries. This caused a discontinuity of flow in the galleries and, consequently, the ground water table is rising at a rate of 0.48 m/yr, causing environmental problems. Research was conducted to rehabilitate the destructed part of the galleries, and to find an appropriate use for the ground water. The study found that the quality of the ground water is suitable for landscaping purposes, that is, for the irrigation of trees and ornamental plants.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03278.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:The karez is a traditional irrigation water source, consisting of hand‐dug horizontal wells, that is still used in parts of South Asia, the Middle East, and North Africa. This paper describes the construction, management, and current problems of karez irrigation systems based on investigations conducted in Baluchistan Province, Pakistan. While karezes have served irrigation needs well in the past, they are now threatened by high costs of labor for construction and maintenance, and by the encroachment of tubewells which lower the water tables on which the karez systems depend. Possible methods for improving karez performance and needs for research are discusse

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03279.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACT:Ground water nitrate contamination is widespread in the United States and especially prevalent in agriculture‐intensive areas such as the Midwest. To reduce human health risks (i.e., methemoglobinemia and cancer risks) from nitrates in ground water supplies, several nitrate risk‐management strategies can be developed based on acceptable levels of human health risks, the reasonableness of the cost required for risk reduction, and the technical feasibility of nitrate‐control methods. However, due to a lack of available information, assessing risk, cost, and technical feasibility contains elements of uncertainty.In this paper, a nitrate risk‐management methodology using fuzzy sets in combination with a multicriterion decision‐making (MCDM) technique is developed to assist decision makers in evaluating, with uncertain information, possible regulatory actions along with the various nitrate risk‐management strategies in order to determine an appropriate strategy. The methodology is illustrated using data from a community with a nitrate water‐qu

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1994.tb03280.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY