红石岩堰塞湖洪水风险分析

Flood Risk Analysis for the Landslide Lake of Hongshiyan

摘要: 牛栏江红石岩形成大型堰塞湖后，及时收集堰塞湖区水文气象和工程设计资料，通过洪水几率、洪水标准、设计洪峰流量和设计时段洪量分析，及时为堰塞湖排险处置提供了洪水分析计算成果，得出堰塞湖在8至9月份发生年最大洪水的几率是大的，为35%;并得出5年和20年一遇的设计洪峰流量，1 d、3 d、5 d、7 d设计洪量成果；当发生5年和20年一遇洪水，通过水量平衡方程进行调洪演算来分析堰塞湖的最高洪水位和最大库容，1 d、3 d、5 d、7 d设计库容超过堰塞湖最大库容的有6个，漫堰的概率为75%；通过洪水漫堰后淹没、溃堰风险分析，得出风险范围是极大的，在堰塞湖上下游83 km的河段，有4213人，6个水电站会受到淹没和溃坝影响。因此，红石岩堰塞湖的排险处置是非常紧迫的。

Abstract: When great landslide lake was formed at Hongshiyan in Niunan River, the hydrometeorological data and engineering design data of landslide lake area were collected rapidly. Through analysis to flood proba-bility, flood standard, design flood peak flow and the flood volume in designing period, the analysis and calculation results of the flood were provided timely to dispose the risk at Landslide Lake. The results indicated the probability of annual maximum flood in this landslide lake was larger in August and Sep-tember, which was about 35%. The flood routing on the flood of every 5 years and 20 years was carried out by the water balance equation to analyze the highest flood level and the largest capacity of the lake. The results showed that there were 6 design capacities in 1 day, 3 days, 5 days and 7 days were larger than the maximum capacity of the landslide lake, the frequency of overflowing weir was about 75%. The risk area is great through risk analysis to submergence and breach when flood overflows cofferdam, 4213 people and 6 hydropower stations alone the upstream and downstream of 83 km landslide river reach may be affected by submergence and weir break. Therefore, risk-elimination is urgent for the land- slide lake of Hongshiyan.