Alternative withdrawal schemes for layered water in large reservoir

In order to setect the reasonable seheme for drawing layered water in a large reservoir and to assess the effect of the temperature of discharged water on the downstream riverine ecosystem , a water temperature model was established by using MIKE3 to simulate the water temperature structure in a large reservoir and the released water temperature downstream the dam. The impacts of three different alterative withdrawal schemes including single-layer entry , multi-layer entry and using stop logs were studied. The results show that the predicted thermal stratification and water temperature profiles in the reservoir are noticeably affected by withdrawal schemes. The optimal withdrawal schemes can effectively raise the released water temperature , so that mitigate the ecological effects. Stop logs schemes can release the surface layer water , its effect on moderation water temperature is better than that of multi-layer entry schemes.