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991.
Wynn R. Walker Gaylord V. Skogerboe 《Journal of the American Water Resources Association》1975,11(4):751-758
ABSTRACT: The increased agricultural efficiency of the American farmer has been a substantial impetus to this nation's rapid urbanization. In many western regions where total water supplies are limited, urbanization has required the transfer of heretofore agricultural water rights to the urban use. A major problem in such transfers has been the value or price of the water. A management level model of a typical urban water system was developed to optimize water supply, distribution, and wastewater treatment alternatives. The values of agricultural transfers were determined as the cost advantages of increasing allowable reuse levels of urban effluents which imply the use of a downstream right. This procedure is justified by the economic theory of alternative cost. Results for a test application to the Denver, Colorado area indicate values on the order of $1,000 per acre-foot of transferable water depending on effluent water quality restrictions and operational policies. 相似文献
992.
Richard H. Hawkins John H. Judd 《Journal of the American Water Resources Association》1972,8(6):1246-1252
The use of salt to melt ice and snow on streets and roads has become prevalent throughout the Northeast. Several states apply as much as 20 tons per lane-mile. Salt runoff may be sorted in various locations within the hydrologic system. Eventually the salt reaches streams and lakes. In Meadowbrook, it was observed that the chloride content reached a high of 11,000 ppm in December 1969. The runoff from the watershed was emitted in several surges. Chloride concentrations declined with the onset of summer, but still remained high, suggesting that some of the salt applied during the past winter appeared in the summer stream flow. Salt runoff entering a small lake, flowed directly to the lake bottom. The buildup of high density saline water in the lower portion of the lake prevented complete mixing in the spring. Incomplete mixing led to anoxic conditions in the lower lake strata. The population of bent hic fauna of the lake was changed by the flow of salt water into the lake. From a total of 10 species of dipteran larva and oligochaetes, only 4 species of the latter remained. 相似文献
993.
Sie Ling Chiang 《Journal of the American Water Resources Association》1971,7(1):171-174
ABSTRACT. High percentage of imperviousness in the city is the source of storm runoff. Roof area contributes significantly to the imperviousness. An attempt to make use of roofs as urban flood control device and water conservation measure is advocated. Two different schemes, one for built-up industrial-commercial area, the other for residential area, are suggested. The former utilizes the roof as detention reservoir for flood control, the latter employs recharge pit to convert runoff into ground water resource. The proposed schemes are not only hydrologically, hydraulically and structurally sound but also economically feasible. It is worth considering in the future planning of urban renewal and urban development. 相似文献
994.
David J. Allee 《Journal of the American Water Resources Association》1971,7(4):774-784
ABSTRACT .This paper attempts to spell out the difficult conditions faced by urban water supply managers in achieving overall efficiency. Based upon these conditions, and changes that are likely in the next decade, it then tries to suggest strategies that would lead to even higher levels of efficiency in the future. A blending of political and economic concepts is used to make what is hoped to be a realistic analysis. What do we mean by “efficient”? The usual welfare economics definition is attainable only under a very special and highly unrealistic set of institutional arrangements. As soon as we delegate responsibility to a specialized agency we provide the opportunity, indeed we make it imperative that, in a social sense, a sub-optimization will take place. From the specifics of the indictment of this sub-optimization we can learn something about the opportunities for more efficient management in the future. In general there is an under-exploitation of multiple-function, multiple-objective opportunities. The pressures for sub-optimization hinge very directly on the sources of support and opposition to the water supply agency. A change requires the creation of a broader political base. The search for regional solutions is largely a political problem, and probably the development of flexible, responsive regional agency, so long sought, is still the answer. 相似文献
995.
In this paper, we analyze the institutional work that underlies the attempt to institutionalize a more active role of citizens in urban planning. We draw on a case in which a group of citizens aims to redevelop a brownfield site into a vital urban area. This citizens’ initiative is co-creating a new form of urban planning with the municipality, private organizations and individual citizens. The study shows how citizens’ initiatives can be a driver for institutional change, but that uncertainties about new institutions tend to reinforce the maintenance of existing ones. This paradox explains why even if the ambition for a new form of planning is widely shared, actually realizing institutional change can still be difficult and time-consuming. 相似文献
996.
997.
城市河流近自然治理--概念构架与治理设计 总被引:6,自引:0,他引:6
河流是城市生态系统的重要组成部分,是城市的自然元素和景观组分,具有提供水生生物生境和水源、调节小气候、美化城市、休闲娱乐等多种生态服务功能.随着城市化进程的飞速发展,城市河流生态系统面临着生物多样性减少、污染加剧等多方面的危害.如何恢复受损的城市河流生态系统已经成为我们的当务之急.对城市河流的生态结构及其在城市中的生态功能进行了简要介绍,讨论了河流生态恢复的近自然方法,并对现有的河流生态恢复存在的问题及发展趋势提出了几点看法. 相似文献
998.
999.
我国城市周边规划建设用地利用探讨 总被引:2,自引:0,他引:2
随着我国城市面积的不断扩大,大量的郊区耕地成为或即将成为城市的建设用地,同时与城市建设相伴相随的建筑渣土的堆放已成为城市的一大问题,本文按照循环经济原则,提出利用规划期内即将建设的城市周边耕地资源建立供应城市建筑的制砖企业,同时利用取土坑填埋建筑渣土,建立城市物质的有效循环,实现城市建筑的循环经济。并对此物质循环方式做了生态经济的分析,也对此物质循环中存在的障碍提出了解决的方法。 相似文献
1000.
Douglas S. Kenney Roberta A. Klein Martyn P. Clark 《Journal of the American Water Resources Association》2004,40(1):77-87
ABSTRACT: Drought conditions in the summer of 2002 prompted several cities along Colorado's Front Range to enact restrictions on outdoor water use, focusing primarily on limiting the frequency of lawn watering. The different approaches utilized by eight water providers were tracked to determine the level of water savings achieved, measured as a comparison of 2002 usage to 2000 to 2001 average usage, and also based on a statistical estimate of 2002 “expected use” that accounts for the impact of drought conditions on demand. Mandatory restrictions were shown to be an effective tool for drought coping. During periods of mandatory restrictions, savings measured in expected use per capita ranged from 18 to 56 percent, compared to just 4 to 12 percent savings during periods of voluntary restrictions. As anticipated, providers with the most stringent restrictions achieved the greatest savings. 相似文献