Influence of Wind Field on Water Residence Time and Pollutant Diffusion in Gangnan Reservoir

Abstract:

In order to explore the influence of wind field on the residence time of Gangnan Reservoir, a hydrodynamic and water exchange model of Gangnan Reservoir was established. Set five working conditions of different wind direction , established connectivity matrices for each partition. The results show that the wind field increases the water flow velocity in the whole reservoir area. Under the condition of east, west and north wind, two circulations with different sizes and directions are formed in the reservoir area, and one circulation is mainly in areas II,III,IV and VII, and the other one circulation is mainly in areas IV and X. Under the condition of south wind, four circulations with different sizes and directions are formed in areas II,III and IV. The overall residence time of the reservoir area under windy conditions is larger than that under windless conditions, but the overall residence time is not much different. Furthermore, The influence of wind field on the residence time of main reservoir area and bay area is different. The residence time of main reservoir area increases slightly under the action of wind field, but the residence time of bay area is significantly shortened. The wind field has little effect on the diffusion of Ⅰ to Ⅳ pollutants in the main reservoir area. Wind field has great influence on the diffusion of pollutants in the bay area, which accelerates the diffusion of pollutants in the bay area. The results show that the water diversion under the condition of wind can not only increase the flow velocity, but also increase the connectivity between the water bodies in the reservoir area, especially in the bay area, improve the water exchange capacity and help to improve the water quality.