Dynamic coordination and control technology of the operating water level during flood season and its application in Xiluodu-Xiangjiaba - Three Gorges cascade reservoirs

Abstract

To satisfy the increasing multi-objective scheduling requirements in flood season of the Xiluodu-Xiangjiaba - Three Gorges multi-function cascade reservoir system located in the lower reaches of Jinsha River and the upper reaches of Yangze River, and simultaneously solve the key technical problems of the resource utilization of floods by joint optimal scheduling of cascade reservoirs. This paper explorers and presents a scientific solution of joint dynamic control of the reservoirs’ operating water level during flood season that suitable for the flood resources comprehensive utilization of the large-scale cascade reservoirs in the Yangtze River Basin. Specifically, the solution is composed of a dynamic control mode for the operating water level of the cascade reservoir during the main flood season (ie, forecast and pre-impounding, grade regulating, and staged discharge control), a phased release theory of the flood control capacity at the end of flood season and a risk analysis model for the decision of the cascade reservoir scheduling. These new technical solutions were successfully applied to the 2016-2019 scheduling practices of the Xiluodu- Xiangjiaba - Three Gorges cascade reservoir system, the world’s largest multi-function multi-reservoir system that operation and management by the China Three Gorges Corporation (CTG). The comprehensive benefits of the cascade reservoir in flood control, power generation, shipping, ecology, and the water supply during reservoir impounding and falling periods have been significantly improved, including greatly reducing downstream flood pressure, increasing power generation and water supply, improving navigation condition, promoting fish reproduction. Meanwhile, it also verifies that these new technologies are scientific, practical, universal and have a broad application prospect.