金沙江溪洛渡水库水沙特征及泥沙冲淤规律

Study on runoff and sediment characteristics and reservoir deposition in Xiluodu Reservoir of the Jinsha River

溪洛渡水电站是金沙江下游梯级开发的第三级,库区位于金沙江下游水沙异源的重度产沙区,其入出库水沙和泥沙冲淤对电站长期运行具有重要影响。以金沙江溪洛渡水库干支流主要控制站的水沙资料及历年断面数据为基础,采用输沙量法、断面法和统计分析,对其入出库水沙特征及泥沙冲淤规律进行研究。研究结果表明:与可行性研究阶段相比,2008-2019年,溪洛渡入库年径流量变化不大,年径流量为1334亿m^(3),相较于可行性研究阶段偏少7.36%;入库沙量大幅度偏少,年平均总入库沙量为1.127亿t,相较于可行性研究阶段偏少54.37%。泥沙沿程主要淤积在常年回水区,沿高程主要淤积在死水位以下,侵占1.3%兴利库容、0.2%防洪库容。水库蓄水后,常年回水区年内泥沙淤积主要发生在汛期,非汛期则有河道泥沙冲刷。干流淤积物干容重自库尾至坝前逐渐减小。

Xiluodu Hydropower Station is the third cascade in the lower reach of the Jinsha River.The reservoir is located in a heavy sediment-producing area in the lower reaches of the Jinsha River.Reservoir sediment deposition processes impact on the long-term operation of the reservoir.Based on hydrological data of mainstream and tributary hydrological stations,and topographic data of Xiluodu Reservoir,the characteristics of runoff and sediment process and reservoir deposition were analyzed.The results show that compared with the feasibility study stage,the annual runoff of Xiluodu Reservoir did not change seriously,with an annual runoff of 133.4 billion m^(3).Compared with the feasibility study stage,the annual runoff was less by 7.36%,and the sediment amount was less significantly.The annual total sediment amount was 1127 billion tons,with an annual sediment amount of 54.37%less than that in the feasibility study stage.The sediment is mainly deposited in the perennial backwater area along the elevation.Sediment is deposited mainly below the dead water level along the elevation,occupying 1.3%of the beneficial storage capacity and 0.2%of the flood control storage capacity.After the reservoir was impounded,the sediment deposition mainly occurs in the backwater area throughout the year.During flood season,there will be scoured.The dry bulk density of the main stream sediment decreases gradually from the end of the reservoir to the front of the dam.