Determination And Application Of The Limited Water Levels For Flood Control

The shortage of water resources will be become a global problem for human being in 21century. China is one of the countries which water resources is much short, so Water resources is very important to China.During the real-time operation of reservoirs, the limit water level is such an important and sensitive index that it directly affects how to reasonably mitigate the contradiction between flood control and benefits of reservoirs. And it is very urgent to describe flood seasons of reservoirs, to reasonably define the limit water level, to find an operable real-time control method of the limit level and to establish an appropriate control model of the limit level.For reservoirs, water storage & flood control are a pair of paradox. If the limited water levels for flood control during flood season are set to be high, it is advantageous for water storage and disadvantageous for flood control and vise versa. In order to resolve this paradox, three concepts and their determining methods of stage design storm, stage design flood and stage the limited water levels for flood control are discussed in this paper. First, divide the flood season into different stages according to hydrology statistic theory, determine stage design storm by the method of frequency lining or stochastic series extending. Second, under the two presumes-—one is that stage design storm and stage design flood have same frequency, the other is that the largest stage design storm is the counterpart of year design flood, determine stage design flood from stage design storm in the light of same ratio scaling. Third, under the type of grading fixed discharge for reservoir dispatch, determine stage the limited water levels for flood control from stage design flood. The above concepts and determining methods are...