|Effects of Ecological Operation of Three Gorges Reservoir on Fish Species with Drifting Eggs
|中文关键词:产漂流性卵鱼类 四大家鱼 生态调度 效果评价 三峡水库
|英文关键词:fish species with drifting eggs four major Chinese carps ecological operation effect evaluation Three Gorges Reservoir
| To mitigate adverse ecological effects, Three Gorges Reservoir has been run according to an ecological operation protocol for 12 years (2011-2022), targeting natural reproduction of fish species with drifting eggs in the river below the dam. In this study, we evaluated the effect of ecological operation of Three Gorges Reservoir over the years based on a constructed evaluation index system. Based on the results we make recommendations for optimizing the ecological operation scheme, aiming to provide a reference for the ecological operation of Three Gorges Reservoir. Based on the effect of discharge scheduling on spawning success of fish species with drifting eggs, the evaluation system developed for this study contains a target layer and criterion layer, consisting of 6 primary indices and 10 secondary indices. The weight coefficient of each index was calculated according to the relative importance of the index as determined by the analytic hierarchy process. From 2012 to 2022, the effect of ecological operation of Three Gorges Reservoir varied significantly from year to year. Fish reproduction was good when ecological operation resulted in optimal hydrological and environmental conditions, such as the duration of flow increase, initial flow, daily rate of increase in flow, peak flow, and water temperature. Ecological operation twice a year was more beneficial than once a year. We recommend that ecological operation of discharge from Three Gorges Reservoir should be controlled to maintain a water temperature above 20℃, and that the discharge process should provide, as close as possible, the hydrological conditions required for target fish species to reproduce. Further, ecological operation should be carried out twice a year, and the flood peak with large pulses should be released according to a schedule that promotes fish reproduction.
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