Research And Application On Estimation Methods Of Design Flood Region Composition

Flood region composition was one of the most important content of design flood estimation in large-and-middle-scale hydro-power project and flood control system project. It has great influence on basin cascade development and determination of the project scale. The paper started with the necessity to study the flood region composition, and by making the comparative research on the estimation methods of design flood region composition, applied this theory to an instance of project. It was especially emphasized that the concrete problem should be solved by a concrete analysis and the method should be applied flexibly. The main works and conclusions were summarized as follows:(1) Based on the review and summary of the available literatures and guidelines of design flood all over the world, the necessity to study flood region composition was put forward. Various kinds of methods were briefly introduced and compared, and the applicability of different methods were pointed out.(2) By the instance of CuiJiaYing navigation and hydropower junction, studies the region flood composition of cascade reservoir. A case study for Cuijiaying navigation and hydropower project was used to analyze the region flood composition of cascade reservoir.Based on in-depth analysis for storm and flood characteristics of middle stream of Hanjiang River, the flood region composition of Cuijiaying catchment was successfully estimated by same-frequency method, which had already been evaluated by appointed commission and adopted by the project establishment.(3) The stepwise same-frequency method and the coupling method of same-frequency and typical year were applied to the estimation of the flood region composition of Dongting lake, which solved design flood estimation of the flood control system that had many flood sources and complicate flood region composition.(4) In order to estimate the flood region composition in un-gauged area, and also account for the need of hydro-power development of basins, this paper made the Maweigou power station lying in Enshi city of Hubei province as the research object, and carried great attempt to the method of the flood region composition in un-gauged area.(5) Through a case study for Cuijiaying navigation and hydropower junction, the application of stochastic simulation in flood region composition was discussed. Multi-station flood was simulated by main-station method which was simple and visual, and single-station flood was simulated by seasonal one rank auto-regression model. The analysis for the estimation result showed that stochastic simulation method was effective.