Risk And Benefit Analysis To Stage Flood Season Limited Water Level Of Reservoir

The per capita own quantity of water resources is only 2200m3 in our country,moreover the per capita quantity of water resources which can be used is 900 m3 after recouping flood runoff and the never-never land underground water resources which are hard to be utilized .By the end of 20th century, the number of anhyetism city has reached up to 400 or more from two or three by 1970s among nationwide 600 cities, thereinto 108 ones were serious shortage of water. The water resource problems have been the key of economic development and social stability. On foundation of water resources in existence, we should father pollution actively, proceed water resources optimizing regulation and dig the benefit and potential of hydropower plant with reservoir as soon as possible!The flood limit water level is a very important index in the course of flood control operation. It is the bonding point of flood control benefit and beneficial use. Due to the condition of flood limit water level, most reservoir in northern aera of our country let out substantive water resources in order to vacate storage at flood season, that there is little water for storage. The result is that quite moiety storm flood resource can't be utilized adequately. On the foundation of analyses drainage area, this article divide the flood season into several stage by handles fuzzy-set analysis and mathematical statistics, then optimize flood limit water level and analyze the risk to corresponding flood limit water level. Finally work out the risk and benefit level of different flood limit water level schemes.In the course of risk analysis, the article considers dam body security and downstream flood control security at the same time. On the condition of different original regulating water level and different downstream safety discharge, calculate the risk of accommodating different frequencies flood. Take both flood courses, original regulating water level and downstream safety discharge as variable in programming, so that it is universal. At last, take Wanjiazhai reservoir as a example, analyze and estimate the risk and beneficial use of different flood limit water level, and ascertain the method of choosing flood limit water level. Furthermore perform the sensitivity analyses on forecast error and regulation time lag.On the basis of 2004 and 2005 function data, when choose 974.0m as the flood limit water level the power benefit is about 1.55 million Yuan, and increasing pondage is about 170.7 million m3.