大广坝流域台风期洪水预报方法的研究

Study of typhoon-period flood forecasting system for Daguangba river basin

大广坝流域洪水由台风雨形成,台风登陆路径的不同造成台风期降雨中心位置分布的差异,另外流域上游的友谊水库对下游大广坝水库天然入流方式的改变,直接导致洪水预报方案的改变,即从全流域产汇流计算改为“上下库区间汇流计算和库区产汇流计算”。通过分析大广坝流域台风雨洪成因及其特点,按降雨类型分别设计了相应的洪水预报方案,经检验,方案预报精度达到甲等水平,可为大广坝电站防洪度汛提供更加准确及时的雨洪信息。

Flood in Daguangba river basin is caused by typhoon rain. The different landing mutes of typhoon result in different sites of rainfall centers during typhoon period. Additionally, the upstream Youyi reservoir has changed the natural inflow course of downstream Daguangba reservoir, which directly leads to the change of flood forecasting mode from runoff yield and conflux of the entire valley to an inter-zone conflux plus runoff yield and conflux of the reservoir area. Based on an analysis of the origin and feature of typhoon rain flood in Daguangba basin, corresponding flood forecasting schemes are designed for different types of rainfall. The resuits of test demonstrate that the forecasting scheme, with a precision up to grade A level, will be able to timely offer more exact rainstorm flood information for flood prevention of Daguangha Hydropower Station.