Seite - 317 - in Book of Full Papers - Symposium Hydro Engineering

reservoirs:China Three Gorges reservoir,Ertan reservoir,Danjiangkou reservoir etc.[11-14] The main parameters of annual precipitation and evapotranspiration are different for each location, as the local climate and topography vary.Generally,annual precipitation and annual air temperature increase;annual evapotranspiration rate decreases in summer,but increases in winter in some places.Calculation simulation and experimental research show China Three Gorges reservoir affects air temperature and humidity mainly between 2km upstream and 10km downstream,and nearcirculation could increase air temperature by about 1℃ duringsummer nights, with a 3% humidity difference within10km ofthe Three Gorges reservoir[15-16]. A world-class hydropower station with large reservoir iscurrently being studied by researchers.It has great water storage capacity,and the local climate is quite complex with the influence of Pacific airflow and Indian airflow in southwest China.Because of actual complex situations and operation data limitations,there are no scholars doing related research for reservoir climate changes in southwest China,especially when the giant reservoir is filled.What's more, local climate around the reservoir is quite different pre and post the hydropower station construction, as well as being affected by reservoir water storage,which could be confirmed clearly by observation of vegetation before and after the reservoir water storage(Figure 1). a.Before water storage b.After water storage Figure 1. Vegetation before and after the reservoir water storage. 2. PHISICAL MODEL A representative giant reservoir and its surroundings were extracted from the typical hydropower station model in Southwest China that could clarify the reservoir climate changes clearly and representatively.The dam is a double curvature arch dam within maximum height of 285.5m,and results in 600m normal pool level and 540m dead storage level,which provides 12.8 billion m3 of total reservoir volume and 6.5 billion m3 of regulating storage volume(Figure 2).As the hydropower station operates normally,the reservoir will submerge some county districts of 317