Hydrodynamic And Water Quality Simulation Of TOC,TN And TP Distribution In Liaohe Estuary Wetland Sediments By Mike

Wetland is a complex with unique natural environment and ecological functions,mainly formed by the interaction of land and water.An important role in the wetland ecosystem is to filter pollutants from atmospheric sedimentation and land runoff to achieve the purpose of purifying water quality.However,when human activities seriously interfere with the purification of wetland,it will lose its ecology.service function.In order to study the pollution of organic carbon(TOC),total nitrogen(TN),and total phosphorus(TP)in the sediments of the Liaohe Estuary wetland,this paper adopts the method of multiple sampling at a fixed point,through the content of TOC,TN,and TP in the collected samples.Measure and establish a hydrodynamic-water quality coupled mathematical model through MIKE for analysis to explore the applicability of the model in the wetland sediments of the temporal and spatial changes and the distribution of pollutant content.The conclusion is as follows:(1)The MIKE 21 FM module in the MIKE software is used to numerically simulate the hydrodynamic conditions of the sediments in the Liaohe Estuary wetland.The collected measured flow and water level data are used as boundary conditions to construct a hydrodynamic model.The 2018 measured data is used for the model Calibration and verification,so that the error situation meets the requirements,the water ecology laboratory module ECOLab is used to perform the water quality analysis on the three water quality parameters selected under the three working conditions before the main flood period in May,the main flood period in July,and the post-September flood period.Simulate,calibrate the parameters of the model and verify the model with the measured data of hydrology and water quality.The calculation results show that the change characteristics of the simulated contour map of water quality can basically reflect the change of the real concentration of sediment pollutants in the Liaohe Estuary wetland,indicating that the established hydrodynamic-water quality coupling model is reasonable.According to the water quality simulation results obtained by the coupled model,it is shown that when the water flows through the wetland,it has a certain purification effect on the pollutants in the wetland sediment,and the purification effect is better during the flood season.(2)In 0～10cm(surface sediment),the contents of TN and TP under the working conditions before the main flood season in May appear to have maximum values in the core area of the near river sampling route,and the maximum value in the experimental area of the far river sampling route value.The TOC content has a maximum value in the buffer zone of the near river sampling route,and a maximum value in the experimental area of the far river sampling route.Under the conditions of the flood season in July,the TN content showed a maximum value in the experimental area of the near river sampling route,and a maximum value in the core area of the far river sampling route.The TP content has a maximum value in the experimental area of the near river sampling route,and a maximum value in the buffer zone of the far river sampling route.The maximum value of TOC content in the near river and far river sampling route appeared in the buffer zone.After the main flood season in September,the TN content showed a maximum value in the core area of the sampling route near the river,and a maximum value in the buffer zone of the sampling route far away.The maximum value of TP content in the near river and far river sampling route appeared in the experimental area.The TOC content has a maximum value in the experimental area of the near river sampling route,and a maximum value in the buffer zone of the far river sampling route.In the 40～50cm(bottom sediment)under the working conditions before the main flood season in May,the TN content has a maximum value in the core area of the near river sampling route,and a maximum value in the buffer zone of the far river sampling route;The maximum value of the content in the experimental area of the near river sampling route,and the maximum value in the core area of the far river sampling route;the maximum value of the TOC content in the near river and the far river sampling route appeared in the buffer zone.The maximum value of TN content in the near river area and the far river area under the conditions of the main flood season in July appeared in the core area;the maximum value of TP content appeared in the experimental area of the near river sampling route,and it was sampled in the far river The buffer zone of the route has a maximum value;the TOC content has a maximum value in the core area of the sampling route near the river,and a maximum value in the buffer zone of the sampling route out of the river.Under the working conditions after the main flood season in September,the TN content showed a maximum value in the core area of the near river sampling route,and a maximum value in the buffer zone of the far river sampling route;the TP content was in the near river area and the far river area The maximum values of all appear in the buffer zone;the TOC content has a maximum value in the experimental area of the near river sampling route,and a maximum value in the core area of the far river sampling route.(3)Comparisons are made through two software maps: In Mike’s hydrodynamic analysis using hydrodynamics,the migration and diffusion of hydrodynamics can better show the distribution of pollutant concentration and verify the credibility of the model.You only need to change the hydrodynamic conditions to predict the water quality and regime,while ArcGIS can only perform spatial interpolation to see the distribution results.Although it is relatively simple when there are experimental data,it can degrade and adsorb the content of pollutants.The distribution of is not well represented,so under complex water conditions,the performance of the model built by Mike is better than ArcGIS.