Study On Lake’s Dynamic Assimilative Capacity Based On Two-dimensional Hydrodynamic And Water Quality Simulation

Lakes are important resources for the production and living of human society.However with the development of social economy,the water pollution of lake has also increased.The study of lake’s assimilative capacity is an important scientific basis to ensure the sustainable utilization of lake water resources and comprehensive control of lake water environment.However the traditional calculation method can only figure a total annual amount,which cannot show the monthly variation within a year.Hence studying on lake’s dynamic assimilative capacity in a year will be necessary,which can satisfy the demand of the fine management of water environment.This paper takes Tangxunhu lake basin in wuhan city as study area,establishes a two-dimensional hydrodynamic and water quality model of Tangxunhu lake,researches Tangxunhu lake’s dynamic assimilative capacity of COD,NH₃-N,TN and TP,then reduction plans are made to reduce excessive pollutants.The main conclusions are as below:（1）Summarizes the theories of lake’s assimilative capacity,two-dimensional hydrodynamic and water quality model,and lake basin pollution load assessment,proposes the research method of lake’s dynamic assimilative capacity based on two-dimensional hydrodynamic and water quality simulation.（2）Analyzes the water quality status and annual change trend of Tangxunhu lake.Now,water quality of Tangxunhu lake does not meet the requirement of its’water quality management target typeⅢ,and presents moderate eutrophication,COD,TN and TP are main pollutants.According to the measured data,the main pollution of Tangxunhu lake are point source,non-point source,internal source and external source of the inflow of Xunsihe river.（3）Constructs the two-dimensional hydrodynamic and water quality model of Tangxunhu lake and verificates it by the monitoring data of Tangxunhu lake.The calculation results show that the annual variation trend of water level,COD,TN and TP are similar with the monitoring data.（4）Study on the dynamic assimilative capacity of Tangxunhu lake’s.Simulating the water status of each pollution reduction plans.The results show that when COD,NH₃-N,TN,TP cut 6013.11t/a、394.69t/a,1001.14t/a、68.55t/a respectively,they can reachⅢclass standard.