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四川汶川茶园沟泥石流灾害特征及危险度评价 总被引:15,自引:1,他引:15
2003年8月9日四川汶川县茶园沟泥石流造成了1人死亡,10人失踪和严重的财产损失.泥石流是由于短历时高强度的大雨激发而形成的.泥石流最大流速为10.8m/s,泥石流洪峰流量为999m3/s,冲出物方量约为5万m3.茶园沟流域内松散固体物质的密度为2.18 g/cm3,含水量为10.7%,空隙率为28%,塑性界限和流性界限分别为18.8%和32.5%,一遇大雨或较长时间的降雨就极易形成泥石流.茶园沟属中度危险的泥石流沟,中度危险的泥石流也造成了严重的人民生命财产的损失,这主要是由于受灾对象,即易损性的特性所决定的.茶园沟泥石流的防灾减灾措施,一是要实行封山育林,停止开矿弃渣;二是要提高公路桥梁的防洪标准,合理布局水利水电设施. 相似文献
74.
可变情报板对交通安全的影响分析 总被引:1,自引:0,他引:1
目前,可变情报板作为最基础、最常用的诱导信息发布平台被大量安装在道路两侧。一方面,它在一定程度上分散了车辆的聚集,减少了车辆的巡游;而另一方面,由于对可变情报板的设置、显示等方面的研究不足,它对交通安全带来了一定的影响,或者诱导效果并不理想。笔者主要围绕北京市西直门桥周边的可变情报板进行调研,从多个方面分析了可变情报板对交通安全的影响,列出了主要的影响因素,如刷新频率、视认性等,并给出了一定的量化指标。 相似文献
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Atsumi Miyake Nobuyoshi Yamada Terushige Ogawa 《Journal of Loss Prevention in the Process Industries》2005,18(4-6):380-383
Organic peroxides (POs) have been widely used in chemical industries as initiators of polymerization, hardening or bridge formation agents, and they are known for its self-reactive and also mixing hazard characteristics when mixed with other chemicals such as acids and alkalis. It is the purpose of this investigation to propose a simple but useful evaluation flow of mixing hazards of POs with other chemicals using conventional experimental techniques such as a glass test tube test, Dewar vessel test and DSC is proposed. 7 kinds of POs (DEPD, THP, TBEH, TBTC, MEKPO, DTBP, THHP) were mixed with sulfuric acids with various concentration, sodium hydroxide solutions, -iron(III) oxide and acrylonitrile (AN).
Based on the proposed evaluation flow the testing results were classified into 4 ranks due to the hazard criteria. Futhermore DEPD/acrylonitrile mixtures were investigated in more detail and the influences of the mixing ratio and the stirring speed were discussed. 相似文献
77.
Ramsis B. Salama 《Water, Air, & Soil Pollution: Focus》2005,5(1-2):27-44
Perth groundwater resources are obtained from three major aquifers that occur beneath the Perth metropolitan area: the Superficial
aquifer, Leederville aquifer and Yarragadee aquifer. Each aquifer has a unique seasonal water level pattern controlled by
soils, geomorphology and geology. Landuse is mainly responsible for variations in recharge; however, the hydraulic properties
control aquifer response and water level pattern to a greater degree. Groundwater in the three aquifers is generally of very
good quality except in localised areas. Salinity increases with depth and in direction of groundwater flow in the three aquifers.
The best water quality is in the Superficial aquifer in the Wanneroo well field area. The geochemistry and stable isotope
signatures from the three major aquifers revealed distinct water types that suggest very little hydraulic connection or mixing
of waters between these aquifers at the present abstraction and recharge regimes. The results also show that the Leederville
and Yarragadee aquifers were recharged during earlier cooler times while the Superficial aquifer is being recharged at present. 相似文献
78.
Abedalrazq F. Khalil Mac McKee Mariush Kemblowski Tirusew Asefa 《Journal of the American Water Resources Association》2005,41(1):195-208
ABSTRACT: Water scarcity in the Sevier River Basin in south‐central Utah has led water managers to seek advanced techniques for identifying optimal forecasting and management measures. To more efficiently use the limited quantity of water in the basin, better methods for control and forecasting are imperative. Basin scale management requires advanced forecasts of the availability of water. Information about long term water availability is important for decision making in terms of how much land to plant and what crops to grow; advanced daily predictions of streamflows and hydraulic characteristics of irrigation canals are of importance for managing water delivery and reservoir releases; and hourly forecasts of flows in tributary streams to account for diurnal fluctuations are vital to more precisely meet the day‐to‐day expectations of downstream farmers. A priori streamflow information and exogenous climate data have been used to predict future streamflows and required reservoir releases at different timescales. Data on snow water equivalent, sea surface temperatures, temperature, total solar radiation, and precipitation are fused by applying artificial neural networks to enhance long term and real time basin scale water management information. This approach has not previously been used in water resources management at the basin‐scale and could be valuable to water users in semi‐arid areas to more efficiently utilize and manage scarce water resources. 相似文献
79.
Douglas G. Boyer 《Journal of the American Water Resources Association》2005,41(2):291-300
ABSTRACT: Water quality indicators of two agriculturally impacted karst areas in southeastern West Virginia were studied to determine the water quality effects of grazing agriculture and water quality trends following initiation of water quality improvement programs. Both areas are tributaries of the Greenbrier River and received funding for best management practices under the President's Initiative for Water Quality and then under the Environmental Quality Incentives Program (EQIP). After 11 years of study there was little evidence to suggest that water quality improved in one area. Three and a half years of study in the other area showed little evidence of consistent water quality improvement under EQIP. Lack of consistent water quality improvement at the catchment scale does not imply that the voluntary programs were failures. Increased livestock numbers as a result of successful changes in forage management practices may have overridden water quality improvements achieved through best management practices. Practices that target well defined contributing areas significantly impacting aquifer water quality might be one way to improve water quality at catchment scales in karst basins. For example, a significant decrease in fecal coliform concentrations was observed in subterranean drainage from one targeted sinkhole after dairy cattle were permanently excluded from the sinkhole. 相似文献
80.
John V. Westra Julie K.H. Zimmerman Bruce Vondracek 《Journal of the American Water Resources Association》2005,41(2):309-322
ABSTRACT: Farmers can generate environmental benefits (improved water quality and fisheries and wildlife habitat), but they may not be able to quantify them. Furthermore, farmers may reduce their incomes from managing lands to produce these positive externalities but receive little monetary compensation in return. This study simulated the relationship between agricultural practices, water quality, fish responses to suspended sediment and farm income within two small watersheds, one of a cool water stream and one of a warm water stream. Using the Agricultural Drainage and Pesticide Transport (ADAPT) model, this study related best management practices (BMPs) to calculated instream suspended sediment concentrations by estimating sediment delivery, runoff, base flow, and streambank erosion to quantify the effects of suspended sediment exposure on fish communities. By implementing selected BMPs in each watershed, annual net farm income declined $18,000 to $28,000 (1 to 3 percent) from previous levels. “Lethal” fish events from suspended sediments in the cool water watershed decreased by 60 percent as conservation tillage and riparian buffers increased. Despite reducing suspended sediments by 25 percent, BMPs in the warm water watershed did not reduce the negative response of the fisheries. Differences in responses (physical and biological) between watersheds highlight potential gains in economic efficiency by targeting BMPs or by offering performance based “green payments.” 相似文献