Modelling Study on Density Currents Induced by Temperature Stratification of Xiangxi Bay, China.

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Zijun Hu, Lingling Wang, Hongwu Tang, Yun Lang

Thursday 2 july 2015

17:00 - 17:15h at Amazon (level 1)

Themes: (T) Hydro-environment, (ST) Ecohydraulics and ecohydrology

Parallel session: 13B. Engineering - River

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In recent years, a series water environment problems induced by temperature stratification of huge reservoirs have got wide attention. A 3 dimensional (3D) temperature mathematical model under Z coordinate is established for the Xiangxi Bay (XXB) of the Three Gorges Reservoir (TGR) to simulate the temperature stratification and density currents of the TGR respectively. The main contents and conclusions are as follows: The XXB is a seasonal temperature stratified reservoir. In detail, the temperature stratification is beginning to appear from spring, most significant in summer, beginning to weaken from September. In the horizontal direction, the temperature gradient along the flow direction is significant in summer and winter, and the lateral temperature gradient is almost zero all year round. The water temperature of the XXB is stratified, so as the water density. Therefore, there are density difference between the main stream of the TGR and the XXB, which makes the main stream of the TGR flow into the XXB at the middle level during stratified periods. The thickness, depth and distance of the density currents at the estuary of the XXB are different with the water level of the TGR and water level range per day. Also, the upstream flow of the Xiangxi River often dives at the bottom of XXB.