Ecological Dispatching Experiment of the Lower Reach of Jinsha River- Three Gorges Cascade Reservoirs Based on Fish Reproduction

After a great number of large and medium-sized reservoirs in the upper reach of the Yangtze River have been built, the temporal and spatial distribution of runoff and water temperature in the natural channel have been changed, thus affecting the propagation of aquatic organisms. In order to reduce the adverse effect of human activities on fish reproduction, taking advantage of the adjustment function of the reservoir, we explore ecological dispatching experiment that is conducive to improving ecology and environment. Xiluodu reservoir carries out dispatch experiment of multi-layer stratified water intake from March to April, to analyze the influence on temperature of discharge water. Experiments on artificial flood dispatch from Xiangjiaba and Three Gorges Reservoir are carried out to explore the effects on the reproduction of fish with pelagic eggs. By 2018, Xiluodu reservoir has consecutively carried out two years of ecological dispatch, Xiangjiaba Reservoir has carried out three times of ecological dispatch, and Three Gorges Reservoir has consecutively carried out 12 times since 2011. Through monitoring data analysis, the water intake temperature of Xiluodu reservoir hydro-generator increased by 0.4 ℃ during dispatching period. The total natural reproduction quantity of four major Chinese carps in the downstream of Three Gorges Reservoir is over 3 billion, accounting for 48% of the total reproduction during the monitoring period. The results show that the water temperature and hydro-ecological dispatch experiment of the lower reach of Jinsha River- Three Gorges cascade reservoirs have promoted fish natural proliferation and improved the aquatic ecosystem to some extent. It provides scientific reference for other large reservoirs to carry out eco-dispatching.