关键词: 梯级水库;消落次序;联合调度;综合效益;三峡水库;长江上游;

Abstract: With the construction and operation of large reservoirs in the upper reaches of the Changjiang River, the contradiction of concentrated drawdown between reservoirs before flood season has gradually increased. In order to explore the reasonable drawdown modes of cascade reservoirs, taking Wudongde, Baihetan, Xiluodu, Xiangjiaba Reservoir (cascade reservoirs of downstream Jinsha River) and the Three Gorges Reservoir as the research objects, three drawdown methods (early drawdown, uniform drawdown, and delayed drawdown) were drawn up, the comprehensive benefits of cascade reservoirs during the drawdown period under different drawdown schemes were compared, and an optimal drawdown sequence for cascade reservoirs was proposed. The results show that during the drawdown period, under the condition of multi-year average inflow and prerequisite of flood control safety, a drawdown scheme of the uniform drawdown in Wudongde-Baihetan cascade reservoirs, delayed drawdown in Xiluodu-Xiangjiaba cascade reservoirs, and delayed drawdown in Three Gorges Reservoir, can gain the largest power generation, reaching 103.922 billion kW·h. When the cascade reservoirs delay to drawdown, the risk of outflow below the minimum discharge standard is the lowest. When adopting a drawdown scheme, that is, uniform drawdown in Wudongde-Baihetan cascade reservoirs, early drawdown in Xiluodu-Xiangjiaba cascade reservoirs and early drawdown in Three Gorges Reservoir, the water replenishment utilization rate of total cascade reservoirs is the highest, corresponding to 2.245 billion m3 of abandoned water. Considering the comprehensive benefits of power generation, navigation, ecology and water supply, it is recommended that the optimal scheme is the uniform drawdown in cascade reservoirs of downstream Jinsha River and delayed drawdown in Three Gorges Reservoir. However in extremely wet or dry years, the uniform drawdown mode should be adopted in time in combination with the forecast. The research results can provide a reference for giving full play to the comprehensive benefits of the upper reaches of the Changjiang River, such as power generation, navigation, ecology and water supply.

Key words: cascade reservoirs; drawdown sequence; joint operation; comprehensive benefits; Three Gorges Reservoir; upper reaches of the Changjiang River