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181.
182.
Jennifer K. Holman‐Dodds A. Allen Bradley Kenneth W. Potter 《Journal of the American Water Resources Association》2003,39(1):205-215
ABSTRACT: As watersheds are urbanized, their surfaces are made less pervious and more channelized, which reduces infiltration and speeds up the removal of excess runoff. Traditional storm water management seeks to remove runoff as quickly as possible, gathering excess runoff in detention basins for peak reduction where necessary. In contrast, more recently developed “low impact” alternatives manage rainfall where it falls, through a combination of enhancing infiltration properties of pervious areas and rerouting impervious runoff across pervious areas to allow an opportunity for infiltration. In this paper, we investigate the potential for reducing the hydrologic impacts of urbanization by using infiltration based, low impact storm water management. We describe a group of preliminary experiments using relatively simple engineering tools to compare three basic scenarios of development: an undeveloped landscape; a fully developed landscape using traditional, high impact storm water management; and a fully developed landscape using infiltration based, low impact design. Based on these experiments, it appears that by manipulating the layout of urbanized landscapes, it is possible to reduce impacts on hydrology relative to traditional, fully connected storm water systems. However, the amount of reduction in impact is sensitive to both rainfall event size and soil texture, with greatest reductions being possible for small, relatively frequent rainfall events and more pervious soil textures. Thus, low impact techniques appear to provide a valuable tool for reducing runoff for the events that see the greatest relative increases from urbanization: those generated by the small, relatively frequent rainfall events that are small enough to produce little or no runoff from pervious surfaces, but produce runoff from impervious areas. However, it is clear that there still needs to be measures in place for flood management for larger, more intense, and relatively rarer storm events, which are capable of producing significant runoff even for undeveloped basins. 相似文献
183.
1959~2008年湖北省暴雨的气候变化特征 总被引:1,自引:0,他引:1
利用湖北省17个气象站1959~2008年逐日降水资料,采用克里格插值法、线性趋势、累计距平、滑动平均及Mann Kendall、复Morlet小波函数等方法分析湖北省暴雨的空间分布规律和时间演变特征。结果表明:湖北省存在以鄂东南和鄂东北为两个暴雨高值高频中心、鄂西北为低值低频中心的多中心分布特征,整体呈现出从东南向西北递减的地域分布,且大暴雨高频区、特大暴雨多发区和暴雨极大值区均出现在鄂东地区。时间演变趋势上,近50年来湖北省暴雨日数呈弱的增长趋势,暴雨量经历了偏少 偏少 偏多 偏多 偏少的年代际变化过程,异常暴雨年中暴雨日数偏多年较偏少年出现的频率高,全省暴雨日数和暴雨量在1978年发生突变,且存在9 a和5 a的周期振荡,而各分区暴雨日数均表现出显著地8~10 a的年代际周期特征 相似文献
184.
突发事件连锁反应的实证研究——以2008年初我国南方冰雪灾害为例 总被引:2,自引:2,他引:0
从突发事件连锁反应分析,认为2008年初我国南方的冰雪灾害是由自然灾害引发的连锁反应事件。选择了新浪网冰雪灾害报道专题的近4 000篇报道作为数据源,从时间、空间和事件角度揭示了此次冰雪灾害的演化过程,并分析了事件扩散的原因。 相似文献
185.
长江三峡水库水污染控制若干问题 总被引:10,自引:0,他引:10
论述了三峡水库几个重要水环境问题,对近年来三峡水库水污染控制科学研究工作进行回顾,评述了一些重要研究成果,就三峡水库水质模拟、水体富营养化、水库泥沙截留淤积和重金属污染等问题进行了深入探讨。基于国际水协会最新推出的河流水质模型,提出了三峡水库水环境模拟研究的观点和方法;基于湖泊(水库)生态动力学模型原理,在对水体中磷元素预测的基础上,从营养盐含量、水深、流速、温度因素等与富营养化非线性映射关系出发,初步建立三峡水库水体富营养化人工神经网络模型,对三峡水库水体富营养化潜势进行研究,分析讨论了一些初步结果;论述了水库泥沙截留淤积及其与水体中污染物,特别是重金属污染的相互作用;建议三峡水库近期内应予以重视的一些重要水环境科学问题。 相似文献
186.
187.
IntroductionWatercontaminantsincludealargenumberofchemicalsrangingfromaromatichydrocarbons,organicsolvents,pesticidesandmetals.Heavymetalcontaminationiscommonlyfoundinareaswhereindustrialeffluentsaredischargedintonaturalwaters .Theharmfuleffectsofsuchm… 相似文献
188.
Combined effects of two sulfonylurea herbicides on soil microbial biomass and N-mineralization 总被引:1,自引:0,他引:1
IntroductionAgrochemicalshavebeenactedaveryimportantroleinagriculturalproduction .Foravoidingdamageofcrops,manykindsofpesticidesareappliedforthereasonofinsect,diseasesandweedcontrolinChina .Scientistshavedonealotofworkonthefateandmetabolismofpesticides,… 相似文献
189.
Leroy F Heitz Shahram Khosrowpanah Jay Nelson 《Journal of the American Water Resources Association》2000,36(3):541-548
ABSTRACT: Historically, storm water management programs and criteria have focused on quantity issues related to flooding and drainage system design. Traditional designs were based on large rainfall‐runoff events such as those having two‐year to 100‐year return periods. While these are key criteria for management and control of peak flows, detention basin designs based on these criteria may not provide optimal quality treatment of storm runoff. As evidenced by studies performed by numerous public and private organizations, the water quality impacts of storm water runoff are primarily a function of more frequent rainfall‐runoff events rather than the less frequent events that cause peak flooding. Prior to this study there had been no detailed investigations to characterize the variability of the more frequent rainfall events on Guam. Also, there was a need to develop some criteria that could be applied by designers, developers, and agency officials in order to reduce the impact of storm water runoff on the receiving bodies. The objectives of this paper were three‐fold: (1) characterize the hourly rainfall events with respect to volume, frequency, duration, and the time between storm events; (2) evaluate the rainfall‐runoff characteristics with respect to capture volume for water quality treatment; and (3) prepare criteria for sizing and designing of storm water quality management facilities. The rainfall characterization studies have provided insight into the characteristics of rainstorms that are likely to produce non‐point source pollution in storm water runoff. By far the most significant fmdings are the development of a series of design curves that can be used in the actual sizing of storm water detention and treatment facilities. If applied correctly, these design curves could lead to a reduction of non‐point source pollution to Guam's streams, estuaries, and coastal environments. 相似文献
190.
Due to ever increasing quantities of waste materials and industrial by-products, solid waste management is the prime concern in the world. Scarcity of land-filling space and because of its ever increasing cost, recycling and utilization of industrial by-products and waste materials has become an attractive proposition to disposal. There are several types of industrial by-products and waste materials. The utilization of such materials in concrete not only makes it economical, but also helps in reducing disposal concerns. One such industrial by-product is waste foundry sand (SFS). Waste foundry sand is a by-product of ferrous and nonferrous metal casting industries. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed as waste foundry sand.Published literature has shown that WFS could be used in manufacturing Controlled Low-Strength Materials (CLSM) and concrete. This paper presents an overview of some of the research published on the use of WFS in concrete. Effect of WFS on concrete properties such as compressive strength, splitting tensile strength, modulus of elasticity, freezing-thawing resistance, and shrinkage are presented. 相似文献