Ecological operation for Three Gorges reservoir

The traditional operation rule of Three Gorges reservoir has mainly focused on water for flood control, power generation, navigation, water supply and recreation and given less attention to the negative impacts of reservoir operation on river ecosystem. In order to reduce the negative influence of reservoir operation, ecological operation of the reservoir should be studied to maintain healthy river ecosystem. The study considered the ecological operation targets, including maintaining river environmental flow and protecting the spawning and reproduction of Chinese sturgeon and four major Chinese carps. Based on the flow data from 1900 to 2006 of Yichang gauge as the control station of the Yangtze River, the minimal and optimal river environmental flows were analyzed, and eco-hydrological targets of Chinese sturgeon and four major Chinese carps in the Yangtze River were calculated. The paper proposed a reservoir ecological operation model of comprehensively considering flood control, power generation, navigation and ecological environment. Three typical periods including wet, normal and dry year were selected and particle swarm optimization was applied to analyze the model. The results show that there are different influences of ecological operation rules on economic benefit of hydropower station and reservoir ecological operation model can simulate the flood pulse for requirement of spawning of Chinese sturgeon and four major Chinese carps. Finally, ecological operation measures of Three Gorges reservoir were proposed. According to the results, by adopting a suitable re-operation scheme, the hydropower benefit of the reservoir will not decrease dramatically while the ecological demand can be met. The results provide the reference for making the reasonable operation schemes for Three Gorges reservoir.