Two-Dimensional Water Environment Numerical Simulation Research Based on EFDC in Mudan River, Northeast China

This paper establishes a two-dimensional (2D)numerical simulation model for water environment of Mudan River using hydrodynamic and water quality modelbased on EFDC. It simulates the migration of CODCr andNH3-N in urban sections of the trunk stream in glacial andnon-glacial periods. It also calibrates and verifies bedroughness and integrated attenuation coefficient ofpollutants. As the findings reveal, bed roughness andintegrated attenuation coefficient of pollutants varysignificantly in icebound and non-icebound seasons:roughness coefficient in icebound season is higher than thatin non-icebound season while attenuation rate in iceboundseason is lower than that in non-icebound season. Inaddition, main factors for attenuation rate drop in iceboundseason are, according to simulation results, temperaturedrop, upstream inflow decrease, and ice layer cover. Icesheet is the major contributor of roughness increase. It isfeasible to apply the 2D water environment numerical modelestablished in this paper to urban sections of Mudan Rivertrunk stream.