关键词: 水温分布, 温度分层, 联合调度, 梯级水库, 长江流域

Abstract: After the impoundment of cascade reservoirs, the natural flow regime and annual water temperature distribution will change, resulting in the change of water temperature distribution in reservoirs. To understand the river water temperature distribution characteristics after the impoundment of Xiluodu-Xiangjiaba-Three Gorges cascade reservoirs, temperature in nineteen cross sections along the Yangtze River were measured. According to the observation data, the water temperature at inlet and outlet of reservoirs, vertical thermal stratification were studied. The results show that the temperature of discharged water in this the reservoirs all increase in the cool season and drop slightly in hot season, resulting in the flattening phenomenon of "high temperature is not high, low temperature is not low". The water temperature stratification occurs in dam upstream area of Xiluodu and Xiangjiaba reservoirs, but the water temperature stratification near the dam area of Three Gorges Reservoir is obviously weakened after the reservoir operation, the maximum water temperature difference at the surface and the bottom is only 2.5℃. The research results can provide reference for combined dispatching of cascade reservoirs, water ecology research and verification of reservoir water temperature mathematical model.

Key words: water temperature distribution, thermal stratification, reservoir joint dispatching, cascade reservoirs