Comprehensive Effect Evaluation Of Jinshawan And Dapu River Es-tuary Coastal Zone Protection And Restoration Project

Beidaihe New Area,located in the west of Qinhuangdao City,Hebei Province,is an ideal seaside summer resort for many tourists.However,in recent years,influenced by human and natural factors such as rapid economic development in coastal areas and storm surge invasion,Jinshawan and Dapu River estuary and coastal zones located in Beidaihe New Area have been damaged to varying degrees,gradually showing problems such as reduced disaster prevention and mitigation ability,damaged Marine ecological environment and ecosystem degradation.In order to protect the ecological environment of the coastal zone and improve the ability of disaster prevention and reduction,Qinhuangdao Ocean and Fishery Bureau has established the coastal zone protection and restoration project of Jinshawan and Dapu River estuary.In this paper,Jinshawan and Dapu River estuary coastal zone protection and restoration project areas and adjacent sea areas are taken as the assessment work areas.According to the Technical Guidelines for the Investigation and Assessment of Coastal Ecosystem Status,Part 8: According to the relevant provisions of Sandy Coast(T/CAOE 20.8-2020),an index system for the evaluation of the comprehensive effect of the project is constructed based on the analysis of the current situation of disaster prevention and reduction and ecological environment of the coastal zone restoration project in 2020(before construction)and 2021(after construction).Based on analytic hierarchy process(AHP),field investigation,numerical simulation and Arc GIS spatial data analysis,the comprehensive effect evaluation system of Jinshawan and Dapu River estuary and coastal zone protection and restoration project was constructed.The main results of this project are as follows:(1)An evaluation system for coastal zone protection and restoration projects has been established.The system consists of four levels,with the comprehensive effect assessment of coastal zone protection and restoration projects as the target level.The two indexes of disaster prevention and reduction benefit and ecological environment benefit are taken as the criterion layer.The benefits of disaster prevention and mitigation include the ability to withstand waves and storm surges and the intensity of coastal erosion.The ecological and environmental benefits include the beach resource endowment,environmental factors,Marine biodiversity and backshore vegetation,with a total of six indicators as factor layers.Nineteen evaluation indicators constitute the index layer.(2)After the construction of the coastal zone protection and restoration project,the work area of Dapuhekou and Jinshawan has the same change law.The sandy headland changes the hydrodynamic direction,the underwater bar increases the elevation,and the wave height attenuation rate increases by 63%,which slows down the erosion and erosion of seawater on the beach and improves the disaster prevention and mitigation ability of the coastal zone.The width of dry beach increased by 24.08～25.77 m;The change rate of backshore vegetation area and coverage increased by 33%-65%.The number of monitoring stations that meet Class I seawater quality standards increased from 93% to 100%;However,the Marine biodiversity decreased slightly due to the impact of engineering construction on its living environment,and the sediment quality grade and sorting degree did not change significantly.Overall,the ecological and environmental benefits became better.(3)Use analytic hierarchy process to evaluate the comprehensive effect.The comprehensive effect evaluation range of Dapuhekou work area increased from 46.74～49.04 in2020 to 57.46～66.46 in 2021.After construction,more areas with good evaluation grade were added.The comprehensive effect evaluation range of Jinshawan work area increased from 39.80～41.96 in 2020 to 57.46～66.46 in 2021,and the areas with poor evaluation grade before construction became average after construction.The protection and restoration project has some effect on the improvement of disaster prevention and reduction ability and eco-environmental benefit in this region.(4)The comprehensive effect assessment of the restoration project can not only comprehensively and quantitatively evaluate the offshore waters of the protection and restoration project and comprehensively grasp the environmental quality of the offshore waters of the restoration project,but also provide scientific basis and guiding suggestions for the construction of the offshore restoration project,further improve the level of accurate Marine management and have good practical significance.