Simulation Of Sudden Water Pollution Events In Lake-reservoir Water Sources Based On EFDC Model

Poyang Lake is the largest freshwater lake in China.Most cities in the Poyang Lake area use Poyang Lake as a source of drinking water.In recent years,with the rapid economic and social development of the Poyang Lake urban belt,the frequency of human activities in Poyang Lake has increased significantly.While the shipping industry in the lake area is booming,it also brings many uncontrollable risks to the water sources of the lake area.The frequent occurrence of water pollution incidents in the lake area has seriously threatened the water safety,water ecology and water environment quality of the counties and cities along the lake.Has attracted widespread attention from all sectors of society.This paper analyzes the characteristics of the temporal and spatial changes of the water quality of Poyang Lake based on the measured data of the Poyang Lake water environment from2010 to 2019,and discusses the water quality evolution law of the Poyang Lake area.On this basis,the Environmental Fluid Dynamics Code(EFDC)is used to build a Poyang Lake hydrodynamic-water quality coupling model,which quantitatively simulates the dynamic change process of the hydrodynamic and water environment of the Poyang Lake water source area;Differentiated scenario simulations clarify the impact of sudden water pollution incidents in the water source on the water quality and emergency response time.The main results are as follows:(1)Combined with the data from 2010 to 2019,the comprehensive nutrition state index(TLI)was used to analyze the eutrophication status of the whole lake in Poyang Lake,and the characteristics of the temporal and spatial changes of the water quality of Poyang Lake were discussed: the water quality of the water source in the past decade The degree of eutrophication is generally fluctuating and rising.There are obvious seasonal differences in water quality during the year.Fall and winter are worse than spring and summer.Water level fluctuations are one of the main reasons for their differences.(2)A two-dimensional hydrodynamic-water quality coupling model of Poyang Lake was built based on EFDC,and the key parameters of hydrology,hydrodynamics and water environment of the model were calibrated and verified using the measured data in 2018.The Nash efficiency coefficient is greater than 0.72,and the average absolute error is within Between 0.18-0.41,the simulation results are in good agreement with the measured values.(3)Based on the results of the identification of potential pollution sources in the Poyang Lake area,6 groups of emergent pollution incident scenarios were set up to simulate the migration and transportation of pollutants in the lake area caused by water traffic accidents during high and normal water periods,and the impact of illegal sewage discharge by enterprises along the lake.The impact of water source areas,and targeted emergency treatment measures for corresponding pollutants,provide scientific support and application cases for the emergency management and long-term protection of lake water sources.