Marine Environment Simulation And Capacity Analysis Of Liaodong Bay

With the steady progress of the comprehensive environmental management of the Liaodong Bay in recent years,the marine environment of the Liaodong Bay has been continuously improved.In order to consolidate the environmental achievements,continue to promote the construction of beautiful bays in the Liaodong Bay area according to local conditions,so as to achieve the goal of"clean sea and beach,flock of fish and gulls,and harmony between man and sea",it is necessary to adopt scientific theories and methods to pollute the Liaodong Bay.Quantitative research on the capacity of the physical environment will provide accurate data support for the goal of land-based pollutants entering the ocean,and deal with marine environmental pollution from the perspective of overall planning of land and sea.In view of the current situation of environmental pollution in Liaodong Bay and the situation of coastal wetlands,this study builds a unified marine environment capacity and total control calculation system for the sea area and coastal wetlands based on the water environment numerical model and the total control planning method.Considering the characteristics of sea area flow field and water exchange,the hydrological characteristics of rivers entering the sea,the status of coastal wetlands,the location of land pollution sources,the amount of pollutants entering the sea,and social and economic development,this paper quantitatively calculated and analyzed the allowable discharge of inorganic nitrogen,active phosphate,COD_Mn and petroleum pollutants from the rivers and direct discharges to the sea of the Liaodong Bay and the environmental capacity of the Liaodong Bay.A comparative study was carried out on the marine environment capacity of Liaodong Bay with or without the coastal wetlands,and the contribution rates of coastal wetlands to the marine environment capacity of pollutants in Liaodong Bay was analyzed.Through numerical simulation analysis,it is found that the effect of marine flow field and water exchange caused by the rivers entering the sea in the Liaodong Bay is mainly concentrated in the sea area near the estuaries.The changes of river flows in different seasons will have a significant impact on the hydrodynamics and material transport velocity in the sea area near the estuaries,but the effect in the sea area far from the estuaries is weak,so it does not affect the overall circulation structure of the Liaodong Bay.There are complex circulation structures in the Liaodong Bay sea,which make the water exchange capacity between the sea area and the open sea weak,and are not conducive to the transportation and diffusion of pollutants to the open sea.The hydrodynamic condition in the northern sea area of the bay is worse,which is easy to cause the accumulation of pollutants.Based on the numerical results of the marine environment of Liaodong Bay,quantitative calculation using the total allocation planning method found that the rivers are the main land pollution sources in the Liaodong Bay.The allowable discharge of river pollutants into the sea shows obvious spatiotemporal distribution characteristics,while the spatiotemporal distribution characteristics of allowable discharge of pollutants into the sea are not obvious.The spatial distribution characteristics of the environmental capacity of the pollutants show that the northern sea area of the Liaodong Bay is accounted for a large proportion,and the southern sea area of the bay is accounted for a small proportion.The seasonal distribution characteristics of pollutants such as inorganic nitrogen,active phosphate,COD_Mn and petroleum pollutants are as follows:more in spring and summer,less in autumn and winter;more in summer and autumn,followed by autumn,and less in spring;more in autumn and winter,and less in spring and summer;the most in autumn,followed by summer and winter,and less in spring.By comparing and analyzing the marine environment capacity with and without the impact of coastal wetlands,it is found that the 12 coastal wetland ecosystems in the Liaodong Bay can increase the marine environment capacity of the Liaodong Bay.The annual environmental respective capacity contribution rate of coastal wetlands to pollutants such as inorganic nitrogen,active phosphate,COD_Mn and petroleum pollutants are 0.30%,0.18%,1.05%and 3.36%.Since the coastal wetland area of the Liaodong Bay is currently small,they have little effect on the marine environmental capacity.By studying the marine environmental capacity of different pollutants in the Liaodong Bay,it can provide a scientific basis for the adjustment of the industrial and agricultural production structure on land,and provide a theoretical basis and data support for the further management of the marine environment in the Liaodong Bay by using the land-sea overall planning method.