Water Quality And Hydrodynamic Simulation Of Plain River Network Based On Mike21

With the acceleration of modernization,many environmental problems have become increasingly prominent,such as water supply safety and water quality water shortage caused by water environment pollution.Water resource protection has become the consensus of the international community.Water resources in China are mainly characterized by uneven distribution,with more in the east and less in the west and more in the south and less in the north.The importance of water resources is self-evidence,the protection of limited water resources is the key to achieve sustainable development.In the plain river network area of south China,although the river network is dense and the total amount of water resources is relatively abundant,the water-quality water shortage is still prominent,which has become an important bottleneck restricting the regional development and the construction of beautiful China.Therefore,how to adjust the water quality and hydrodynamics of plain river network is very important.In this paper,taking Nanxun Shenzhuang Yang ponder District in Hu Zhou City,Zhejiang Province as an example,through field investigation and data collection,the topographic map of the study area was constructed.Based on Mike21 hydrodynamic-water quality model software build,and three into water flow according to field situation,whole increased by 10%-30% respectively,comparing the design of the five groups of filling water program.The research results of this paper can provide a theoretical basis for the subsequent water body governance in the study area,and also provide some reference for water body governance in plain river network area.The main contents of the paper are as follows:(1)In line with the measured topographic and geographic data,this paper constructs a two-dimensional hydrodynamic model of the study area by unstructured grids.And the water quality module is written through ECO Lab,on the basis of the hydrodynamic module.Then,a water-quality module that can be applied to area water quality changes is established.(2)ed on the two-dimensional hydrodynamic-water quality model,this paper simulates and analyzes five water replenishment schemes with different replenishment water amounts and locations.The results show that different water-replenishment schemes have different effects on water-quality improvement.When the location of the replenishment point is determined,the scheme with large replenishment amount is better than that with small replenishment amount.When the replenishment amount is determined,the scheme with more replenishment points is better than that with fewer replenishment points.Therefore,according to the simulation results of the five schemes,it can be seen that the water replenishment effect is optimal when the inlet flow is increased by 20%(3)The GM(1,1)model and Markov model are constructed based on the characteristics of the water quality data and prediction models in the study area.Taking the measured data and predicted value in 2021 as an example,the accuracy of the two models is compared.The result shows that the relative error of the gray Markov model is smaller and the model accuracy is higher.Based on the two prediction models,the water quality in 2022 is predicted and analyzed,and it is conclusion that two models have the good tendency for the future water quality change in the study area.There are risks in TN and TP water quality parameters of exceeding the standard,which should be treated and prevented.