Study On Surface Water Environment Simulation In The Yi-luo River Basin

The Yiluo River,an important tributary of the Yellow River,is one of the important sources of runoff in the lower reaches of the Yellow River.The water environment problems in the Yiluo River Basin directly affect the sustainable utilization of water resources and ecological environment protection in the lower reaches of the Yellow River.However,with the rapid development of society and economy in the Yiluo River Basin,the basin is faced with a series of water environmental problems in its governance and development,and the water pollution problem in local urban rivers is severe due to intensive human activities.Taking the Yiluo River Basin as an example,based on the systematic analysis of the river hydrological situation and water environment problems,this paper evaluates and analyzes the current water resources and water environment of the Yiluo River Basin by statistical analysis method,identifies the key areas of water pollution in the Yiluo River Basin,and constructs a regional water environment numerical simulation model to simulate the water quality evolution process of the river under three different hydrological conditions.Finally,the mechanism of water environmental response and pollution in the key water environment is revealed,and the corresponding water environmental protection management strategies are proposed.Through field investigation and data access,the current situation of surface water environment in the Yiluo River Basin is systematically analyzed and evaluated.Combined with the investigation of pollution sources in the basin,the main problems existing in the water environment of the basin are summarized and analyzed,and the key simulated reaches of the model are determined.Then,combined with the collected hydrological,meteorological,river topography,pollution source survey data and water quality monitoring data,a water environment simulation model based on Mike21 coupling of hydrodynamic module and water quality module is constructed.By testing the water quality of two sections,it reveals that the average value of Nash efficiency coefficient NSE of the simulated value and the measured value in these sections is 0.86,and the average value of certainty coefficient is 0.90.Therefore,this model is highly proper and accurate.The model is used to simulate the watershed water environment under three different hydrological conditions of typical wet year,normal year and dry year,it is concluded that the spatial and temporal distribution of water quality in the region has the characteristics that the water quality in the wet year is better than that in the normal year,and the water quality in the dry year is the worst.The water quality of the river reaches in the year is better in the flood season which is from July to September than that in the non-flood season.Furthermore,there are several pollution source outbreak points near the sewage outlet of the river,and the volume of sewage discharged into the river has exceeded its pollutant carrying capacity.According to the simulation results,suggestions and management strategies for refinement management are proposed.