Abstract: Based on the hydrologic and meteorological characteristics of the upper Yangtze basin, the timing of reservoir early impoundment is determined in this work. We construct a multi-objective impounding operation model and solve it using a Pareto-archived dynamically dimensioned search (PA-DDS) algorithm to obtain a series of Pareto fronts. The results demonstrate that when an optimal joint impounding scheme is applied, the starting impoundment dates of Wudongde, Baihetan, Xiluodu, Xiangjiaba and Three Gorges reservoirs can be advanced up to Aug. 1, Aug. 1, Sep. 1, Sep. 1 and Sep. 10 respectively, without lowering the design flood control standard. The proposed scheme can generate 3.68 billion kW?h more power (increase 3.12%) annually in comparison with the designed impounding rules and improve the full storage rate to 95.1% (increase 3.38%). For normal and dry years, these starting impoundment dates can be further advanced to Aug. 1, Aug. 1, Aug. 25, Aug. 25 and Sep. 1, which can generate 4.58 billion kW.h extra power (increase 4.1%) and the full storage rate increases from 88.5% to 93.9%.

Key words: cascade reservoirs, early impoundment, joint operation, flood control risk, optimized impounding rule