Study On Hydrodynamic And Water Exchange Characteristics Of Caofeidian Wetland

As one of the world's three major ecosystems,wetlands are facing different degrees of degradation.As the supplement of wetland ecological environment,the quality of wetland water directly determines the quality of wetland ecological environment.The landscape function and water quality of wetland waters are often affected by water exchange capacity,so it is of great significance to master the hydrodynamic and water exchange rules of wetlands.Based on the research background of Caofeidian wetland,the hydrodynamic and convection diffusion models were established,and the flow field,water displacement and water renewal time of Caofeidian wetland under the control of different water amount were discussed.(1)Taking the Caofeidian wetland as the background,the mathematical model of hydrodynamic and convection diffusion was established,and the main parameters in the mathematical model were given.By comparing the measured data and simulated data of the depth of water and the water level,the accuracy of the mathematical model was checked and verified.(2)In this paper,two concepts of stagnant water area with flow rate less than 0.000 5 m/s and that with flow rate less than 0.001 m/s are adopted to analyze the changes of two stagnant water areas under different flow conditions.The results show that the area of stagnant water gradually decreases with the increase of flow rate,but when the flow rate increases to a certain extent,the area of stagnant water gradually tends to be stable and no longer has a significant decrease.(3)This paper introduces the research method of water exchange rate and analyzes the water exchange capacity under different flow conditions.The results show that the water displacement rate increases with the increase of water diversion flow rate and water diversion time and tends to be stable.Under different conditions of water diversion flow,when the water diversion time reaches 30 days,the water displacement rate no longer has a significant increase,but eventually the whole water area does not reach complete water exchange under various conditions.(4)In this paper,the water renewal time of Caofeidian wetland under different water diversion flow and different water diversion time was analyzed.The results show that the regeneration time of water in Caofeidian wetland decreases with the increase of diversion flow,and the regeneration time of water is sensitive to diversion flow.Most water bodies in the study area have a relatively short water renewal time,but the water renewal time in the bay of several typical lakes is relatively long,and the water renewal time does not decrease significantly with the increase of flow.