Water Quality Simulation Of Minjiang River Basin In Central District Of Leshan

Water quality model is a general mathematical model to describe the physical mixing, transport, and transformation. The model is a mathematical mean and tool based on-the pollutants discharged into water to analysis and predict the future state of water quality.U.S. Environmental Protection Agency's QUAL2Kw model is applied to simulate the water quality of the Minjiang River in central district of Lesha n.QUAL2Kw for supporting the Branch-like stream is a one-dimensional, co-mprehensie and versatile stream water quality model, is widely used in river water quality planning and management.The relevant monitoring data of water quality in central district is analyzed for evaluating environmental water quality. Single-factor evaluation method is used to get the main pollution factor of Minjiang River basin and the result is BOD and ammonia nitrogen. The model parameters are analyzed and identified by hydrology and water quality data. QUAL2K model is verified though applicability and accuracy. The simulation results of dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen (NH3-N) and total nitrogen (TN) is studied, and the water quality change trend is predicted. Finally, the recommendations of controlling the polluted river in the study area are proposed.The results show that:the main source of nitrogen pollution is sewage. Therefore, the primary pollution control objective must be point source pollution and diffuse source of domestic wastewater in rural areas. The water quality of the Minjiang River is affected by the water quality of Dadu River and QingYijiang River. Due to population growth in the next five years, the water quality of Minjiang River basin in central district of Leshan will have a decline in some degree. Therefore, centralized treatment of urban sewage should be focused on.