长江上游水库群联合调度下的河流水文情势研究

长江上游水库群的联合调度运行必然会对下游河道径流产生影响。选择北碚、高场、宜昌站作为水库群串、并、混联运行下的控制断面,通过IHA法选择出受水库群联合调度影响的14个水文指标,并采用CRITIC法改进RVA完成串并混联运行模式下的水文指标变化趋势和整体水文变异程度的研究。分析结果表明:①随着水库群联合运行数量的增加,长江干支流河道水文情势改变幅度增大;②水库群联合运行会使汛期流量显著降低,非汛期流量增加,同时会造成年最大(小)流量呈减少(增加)趋势;③水库串联运行模式会使最大流量发生时间延迟;并联运行模式会使汛期流量坦化现象更加显著;混联运行模式对水文情势的改变程度主要受调度方式和气候变化的影响,上游混联模式使宜昌站水文情势为低改变度。

Study on river hydrology regime under joint operation of cascade reservoirs in upper Yangtze River

It is inevitable that joint operation of cascade reservoirs in the upper Yangtze River will exert certain effects on the runoffs in the lower river channel. We selected Beibei, Gaochang and Yichang stations as controlling cross-sections, and used IHA method to identify fourteen hydrological indexes that are influenced by the operation of reservoirs. We studied the varying trends of these indexes and the degree of hydrology variations under cascade reservoirs’ operation modes of series, parallel and series-parallel. The results show that: ① as the number of cascade reservoirs in operation increases, the variations in hydrology of mainstream Yangtze River tend to increase; ② joint operation of cascade reservoirs significantly decreases water flow during flood season; meanwhile, the maximum discharge throughout the year tends to decrease, and vice versa; ③series operation will delay maximum discharge and parallel operation will reinforce the evenness of discharge process during flood season; the variation of hydrological regime caused by series-parallel operation is mostly affected by the operation mode and climate change, series-parallel operation has low impact on the hydrological regime of Yichang station.