2017年汛期三峡水库城陵矶防洪补偿调度影响分析

2017年6月下旬至7月初，长江中下游连续发生两次强降雨过程，7月1日长江形成2017年第1号洪水，长江中下游干流莲花塘以下江段及洞庭湖、鄱阳湖水位全线超警，发生了中游型大洪水。为减轻长江中下游防洪压力，避免莲花塘站超保证水位，7月1～3日，对三峡水库进行了城陵矶防洪补偿调度，将出库流量由27 300 m3/s减至8 000 m3/s。对2017年汛期三峡水库对城陵矶进行防洪补偿调度后，水库泥沙淤积、荆江三口分流、坝下游河道冲淤与崩岸以及长江中下游洲滩淹没等影响进行了分析。结果表明，调度实施后，显著减轻了洞庭湖区及长江中下游干流的防洪压力，有力保障了长江中下游的防洪安全。研究成果可为三峡水库制定科学调度方案、进一步发挥三峡工程综合效益提供支撑。

Effect of compensation operation of Three Gorges reservoir to flood control ofChenglingji reach during flood season of Changjiang in 2017

From late June to early July of 2017, middle and lower reaches of the Yangtze River experienced two consecutive heavy rainfalls, and Changjiang No. 1 flood formed on the July 1st, during which water levels of Lianhuatang station and its lower reaches, Dongting Lake, and Poyang Lake had all exceeded warning levels. In order to alleviate the flood control pressure in the middle and lower reaches of the Yangtze River and keep water level of Lianhuatang station below its highest safety level, Three Gorges reservoir carried out compensation operation to Chenglingji reach during July 1st and 3rd, which reduced the reservoir outflow from 27 300 m3/s to 8 000 m3/s. Aiming at this compensation operation, we analyzed its impacts on reservoir sediment deposits, the flow diversion of the three distributaries of Jingjiang River to Dongting Lake, river channel erosion and river bank failure in the downstream of dam site, and marshland submerge. The results showed that the compensation operation had significantly alleviated flood pressure in middle and lower of the YangtzeRiver, ensured the flood control safety, and the operation experiences could provide reference for preparing more scientific operation solutions in future.