GIS-based Numerical Simulation Platform For Sandy Coast Erosion And Engineering Applications

Coastal erosion is the recession of coastlines and erosion of beaches caused by dynamic shocks.There are two causes of coastal erosion: one is due to natural causes(River migration,Sea level rise or Marine power enhancement,etc.);The other is human-induced causes(construction of barrages,the mass exploitation of beach sand,deforestation denudation of mangroves,etc.).In recent years,with the improvement of living standards,more and more ecological restoration projects have been built.Therefore,accurate numerical simulation of wave and sand coastal erosion in the project area is very important,which has guiding and reference significance for engineering design and optimization.Wave numerical model SWAN and sediment transport model XBeach are widely used in academic research.Due to the lack of user interface,pre-processing interface,post-interface,the operation of building model is cumbersome,and the popularization rate of engineering application is low.In this paper,GWAB(numerical simulation of waves and beaches based on GIS)is developed based on GIS platform.Referring to Mike's operation process,GWAB's overall architecture includes pre-processing module,core computing module and postprocessing module to solve the model compatibility problem;User interface,running interface and result display interface are used to solve the complicated problem of model operation.Based on the multi-verification point wave numerical simulation of SWAN model,the applicability of model in Bohai Sea is verified.Compared with the measured data,ECMWF wind field can represent the actual wind field in the project area.Based on the 39-year wave numerical simulation from 1981 to 2019,the wave elements of different return periods at Qinhuangdao and Dapuhe sites are deduced.Qinhuangdao station is mainly affected by SSE,S and SSW waves,while Dapuhe station is dominated by ENE,SSE and S waves.About 80 km of sandy coastline in Qinhuangdao has been eroded,accounting for 49% of the length of the Qinhuangdao coastline.Therefore,beach maintenance is very important.The wave conditions of the model are: wave elements of different return periods derived from 39 years long-term wave numerical simulation.GWAB is used to complete the shoreline rehabilitation project from Shihekou to Tiemen.The numerical results of SWAN nested model in GWAB are presented.The wave and coastal erosion of the rehabilitation project are simulated by SWAN and XBeach coupling model.