Numerical Simulation Study on Water Quality of a Pumped Storage Reservoir in Arid Region

The reservoir is very important in the arid region for water supply. It is of great significance for reservoir management and local economic development that ensuring the water quality safety. To make a quantitative research on migration-diffusion rules of contaminant in the reservoir, a numerical simulation on water quality of a reservoir in the arid region was studied. Taking Yazidang Reservoir as an example, three-dimensional hydrodynalic and water quantity model were constructed. And the model was validated with monitoring data. Utilizing the model, a research on migration and diffusion of COD and ammonia nitrogen and the distribution of water concentration when the reservoir is at different operative conditions was carried out. The results show: the diffusion of COD and ammonia nitrogen in Yazidang Reservoir is depended on flow field. And the migration and diffusion of contaminants vary in area when the reservoir is filling with water, specifically, the farther away from the inlet the affection by filling is lag.The change of contaminant concentration is small and the contaminant has seen a decreasing trend when the reservoir is not filling with water. So it is very important to ensuring the water supply quality of Yazidang Reservoir and the time of filling water should be set in light of its conditions.