Spatial analysis and simulation study of rainfall runoff pollution for a tidal river network

To explore the spatial distribution characteristics and pollution pattern of non-point source pollution of the tidal river network in the Maozhouhe River basin, the river network water quality under typical rainfall scenarios was simulated and analysed based on spatial analysis, statistical analysis and hydrodynamic-water quality coupling simulation method. An ecological water supply optimization strategy based on the target of water quality improvement was proposed. The results showed that the combination of hierarchical clustering aggregation algorithm and K-means can preferably distinguish the level and class of non-point source pollution. The water quality of the Shiyanqu River and the middle and upper reaches of the Songganghe River recovered slowly after rain fall due to the high non-point source pollution load and the lack of ecological water supply. A local optimized ecological water supply scheme was proposed based on the principle of constant amount of water replenishment. The recovery speed of water quality in key polluted rivers after rainfall was doubled by the optimized results, and the overall stability of river water quality in the basin was improved. The research conclusions provide support to the further understanding on the water pollution characteristics of the Maozhouhe River basin and the delicacy management of watershed water environment. © 2021, Editorial Board of China Environmental Science. All right reserved.