三峡水库汛期沙峰预报技术及排沙调度实践

Technology of Forecasting Sediment Peak and Practice of Sediment Reduction Dispatch in Three Gorges Reservoir During Flood Season

水库排沙调度是三峡水库安全运行和发挥综合效益的关键技术问题。基于长序列实测水沙资料和水库调度运行情况,系统阐述了三峡水库汛期水沙特性、沙峰预报技术体系和水库汛期沙峰排沙调度试验效果。2012年以后三峡水库汛期径流占全年总径流量的45%,但汛期输沙占比达到84%,场次洪水输沙占比明显增大,且存在明显的水沙输移异步现象。基于泥沙实时报汛数据,构建多形式边界预报模型和库区水沙输移模型相耦合的水库泥沙实时预报系统,能够预报沙峰传播至坝前的时间和相应的含沙量,为水库汛期的沙峰调度提供必要的技术支撑。目前三峡水库已成功开展多次沙峰排沙调度试验,取得了预期效果,经调度后水库排沙比显著增大,场次洪水排沙比在27%~39%范围内。

The scheduling for sediment discharge from the Three Gorges Reservoir(TGR)is a crucial technical issue influencing its safe operation and overall benefits.Based on long time series measured water and sediment data and reservoir operations,we expound the water and sediment characteristics in TGR during flood season,the sediment peak forecasting techniques and sediment reduction scheduling strategies in practice.Results indicate that after 2012,the flood season runoff in TGR constituted 45%of the annual total runoff,while sediment transport during this period reaching 84%.The proportion of sediment transport during each flood event notably increased,highlighting an asynchronous pattern between water and sediment transport.Leveraging real-time monitoring data,we built a sediment forecasting system integrating multi-form boundary prediction model and reservoir water-sediment transport model.This system forecasts the time of sediment peak arriving dam and the corresponding sediment load,offering technical support for sediment reduction dispatch during flood season.Successful operational tests of sediment peak discharge in TGR have yielded expected outcomes,significantly increasing sediment discharge ratios within the reservoir.During each flood event,sediment discharge ratios ranged from approximately 27%to 39%.