乌江干流中上游水电梯级开发水温累积效应

以乌江流域洪家渡库尾至乌江渡坝下的水电工程干扰典型段为研究区域，利用建坝前后的水温实测资料，采用建坝前天然水温和建坝后下泄水温比较法，对乌江干流梯级水库水温时空分布特征进行分析。研究结果表明：对天然水温改变最大的电站为洪家渡和乌江渡，前者是受水库水温结构自身影响，后者是梯级联合运行的结果；梯级联合运行使库区水温分层有所减弱，随着时间的推移或上游梯级电站的建成，电站下泄水温年变化过程趋于均化，与天然水温的延迟也越加明显；不同的水库水温结构对水温累积效应的影响也各不相同，稳定分层型水库对水温累积具有正效应，混合型水库具有负效应，过渡型水库处于两者之间，体现了梯级电站的水温累积影响，为研究减缓下泄低温水的对策措施提供依据和参考。

CUMULATIVE EFFECTS OF WATER TEMPERATURE BY CASCADE HYDROPOWER STATIONS BUILT ON UPPER AND MIDDLE REACHES OF THE WUJIANG RIVER

This paper investigated spatio temporal distribution characteristics of Wujiang River water temperatures along the reaches from Hongjiadu Dam tail to downstream of Wujiangdu Dam by comparison of natural water and discharged water temperature.The data were derived from section in front of the dam stratified in the vertical direction.The research result indicates that,natural water temperature is changed rapidly by the built of Hongjiadu and Wujiangdu Hydropower Station.The former is caused by temperature structure and the latter is a result of the joint operation.The stratification in reservoir area is weakened.The delay and evenness of the outflow temperature course is further strengthened.Reservoirs with different water temperature structure have different cumulative effects on water temperature.Stratified reservoir has positive effect on cumulative effects,while mixed reservoir has passive effect.Cumulative effects are obtained,which would provide a reference for large scale hydropower station operation in order to reduce cold water discharge effects on water temperature.