Abstract: To coordinate between flood control and profit promotion and enhance the efficient utilization of flood resources, we proposed a stage-based division of flood season using the improved fuzzy set method, and subsequently established a system coordination degree model to calculate the dynamic control domain of flood limit water level. The limit water levels in Silin Reservoir, as an example, in pre-flood season and post-flood season are directly proportional to the synergetic contribution degree of power generation benefit, but inversely proportional to the synergetic contribution degree of flood control risk. To achieve the maximum degree of system coordination, the dynamic control domain of flood limit water level is recommended to be [435, 437]m and [435, 438]m in pre-flood season and post-flood season, respectively. These recommendations would lead to additional electricity generation of 2 169.907×10⁴ kW·h and 6 509.722×10⁴ kW·h, and an increase in water resources utilization of 0.716×10⁸ m³ and 1.079×10⁸ m³, during the pre- and post-flood seasons, respectively. The findings of this study contribute to improved flood resource utilization and offer valuable insights for the safe and reasonable operation of reservoirs.

Key words: flood limited level, flood season staging, improved fuzzy set analysis method, dynamic control bound, system coordination degree