Simulation of diffuse source polluted water environment based on MIKE21: A case study of the urban section of the Bai river

Abstract Affected by urban construction and industrial discharge, the diffuse source pollution of river water environment in sections is becoming more serious. The use numerical models can accurately efficiently simulate process analyze its evolution. Based on MIKE21, model Bai constructed. After parameter calibration, it proved that has high accuracy. discharge this section 2018, simulated under three hydrological conditions, BP neural network used to pollution. Network assessment quality dry years. results showed four indicators spatial distribution characteristics upstream>urban section>downstream, year temporal flood season better than a non-flood season. mean value coefficient certainty R2 reaches 0.94 when comparing measured values, which indicates applicability satisfactory fit. If does not meet standard, should be reduced from May October. This study provide reference guidance for control.