The thermal structure of a typical canyon reservoir (SW: China)

Water temperature is the main component in water quality assessment of hydropower project. In this paper, a 3-D model of thermal-hydrodynamic was developed to simulate the thermal structure in YE reservoir, a canyon reservoir in southwest China. The simulated results show that the reservoir develops the thermal stratification from January to October, during which from January to April, the thermal structure is the inversion. From November to December, the simulated results show that the reservoir displays a mixed thermal structure. At the same time, we found that the maximum water temperature on the surface of the reservoir near the dam appears in August while the maximum air temperature occurs one month earlier. Compared with natural temperature before reservoir built, variation of outflow temperature is relatively large, which may influences the ecological environment of downstream areas. So this 3-D model can be used to predict the thermal structure in canyon reservoir, and also provide further technical support for the water environment assessment.