LUO Hui-huang 1, LI Qian 1, LI Chong 2 (1. China Institute of Water Resources and Hydropower Research, Beijing 100038, China, 2. China Three Gorges Corporation, Beijing 100038, China)

Abstract: National nature reserve of rare and endemic fish in the upper Yangtze River ranges from 1.8 kilometers downstream of Xiangjiaba Reservoir to Xiaonanhai Reservoir in Chongqing. After the operation of the four-stage cascade reservoirs in the lower Jinsha River, the released flow will cause the change in the natural water temperature in the downstream river, which has a direct influence on fish growth and reproduction. In this study, the parameters of the CE-QUAL-W2 model were determined and validated by measured water temperature in Ertan Reservoir. Then the model is used to predict the temperature of dis charged flow of the Xiangjiaba reservoir under two cases: the joint operation of Xiangjiaba and Xiluodu reservoirs and the joint operation of all the four reservoirs operation. Based on the results, the influence of the changed water temperature on fish breeding period was analyzed. The results indicated that, within the 35 species of rare and endemic fishes which have the record of temperature requirement in reproduction period, 34 species are affected under the joint operation of two hydroelectric reservoirs except for Euchiloglan siskishinouyei, and all 35 species are affected when four reservoirs are operated together.

Key words: water temperature prediction, cascade reservoirs, fish impact, Jinsha River, CE-QUAL-W2

Published in: Journal of China Institute of Water Resources and Hydropower Research (Vol. 10 No. 4, 2012)