Study On Water Temperature Distribution Impact Of Reservoir And Downstream Due To Variation Of Water Level

The temperature of let-down flow water is always different from natural channel after the hydro project had been estatablished. However, water temperature is one of the most vital indicator. For instance, water temperature has close relationship with dissolved oxygen concentration. Not only the growth and reproduction of part of aquatic creatures also require strict condition, but also series of biochemical reactions which are closly related to water temperature. Before the hydro project construction is completed, it is quite important to predict variation of water temperture by scientific simulations and suggest measures to weaken impact of water environment. This thesis focuses on GuoLangQiao hydropower in Tianquan County, Sichuan Province, predict water temperture by MIKE3 with the result of detailed as follows.(1) Because of the lack of water temperture data in the study area, in order to obtain the comparable accurate information of water temperture, this thesis adopts new method with analysis of meteorological factors which effect water temperature and establish relations between water temperature and meteorological factors by nolinear fitting and correcting with altitude.(2) The main reason that noticeably compacting upon water temperature by different operations is the water level. In the previous studies on water temperature, the water level is not enough valued, which causes certain declination to the simulated results. This thesis adopts methods, of which both upon varying elevation and constant elevation, dealing with annual simulating water temperature of the same single reservoir and proves the better reliability of the result through the method of varying elevation.(3) By adopting varying elevation measure,this thesis simulates annual operation condition and analyses the annual varying regulation of normal year water temperature, as well as analysis upon reservoir temperature structure in the same period under three different operating condition by reservoir operation mode and varying elevation. This thesis also explains the reason of difference, analyses the most unfavorable impact and gives reasonable suggestions.