Assessing effects of non-point source pollution emission control schemes on Beijing's sub-center with a water environment model

A high-quality water environment is a strategic demand for constructing Beijing's Sub-center. Controlling non-point source (NPS) pollution is the key to water environment management in Beijing's Sub-center. We developed a water environment model of Beijing's Sub-center using MIKE 11. Ammonia-Nitrogen and Total Phosphorus concentrations and Chemical Oxygen Demand were used as pollution indicators. Water quality response to the control of agricultural and urban NPS pollution under different scenarios was predicted. The effects of different scenarios were evalu-ated. Results show that water quality in Beijing's Sub-center can be considerably improved by controlling emissions of NPS pollution. Reducing agricultural NPS pollution is the key to reducing Ammonia-Nitrogen and Total Phosphorus concentrations and improving water quality. Results also demonstrate that water quality response varies with land use type. This study aims to provide reliable and practical information to support water pollution control in Beijing's Sub-center, especially NPS pollution. This water environment model fills the gap in the NPS pollution simulation in rivers in Beijing's Sub-center and promotes the application of the water environment model in water pollution management.