Study On The Coastal Erosion And Protection Of Jiulong Bay, Weihai

Jiulong Bay lies in the south of Weihai Bay,the coast of which belongs toheadland-bay sandy coast with high quality beach.In recent years,coastal engineeringhas been constructed all around,as a result of which,the hydrodynamic conditions andsediment transport trends have been changed obviously,causig the beach been erodedseriously,so the study on coastal erosion status quo,causes and protective measures ofJiulong Bay has certain guiding significance for coastal construction.In this paper,the surface sediment data,remote sensing image data and thetopography data of the study area have been processed,and sediment transportcharacteristics of the study area have been analysed,besides,the coast erosion anddeposition trends of the study area have been studied applying the headland coastbalanced shape model,using the above-mentioned methods,this paper has come to theconclusion that from the year of2006to2010,the coastline in the study area showedthe trend of retreating,the coastal retreating rate between Jiulong River and Chengziriver is about3.8m/a.The sediment of the study area has been transported in offshoredirections,the beach profile shows the characteristics of storm beach,and that thebeach profile form is shaped by large waves,besides,the direction of longshoretransport is from west to east,the sediment was transported to the east side of the studyarea and settled down,leading to the erosion phenomenon of the west side being moreserious,the water-depth change in front of the vertical revetment in the south ofChangfeng river is more than0.5m.Base on systematic analysis of the sediment transport law and erosion anddeposition trends of the seabed,this paper have especially studied the couplingmechanism of the hydrodynamic and coastal erosion using numerical simulationmethod to figure out the major factor causing the erosion in the study area.The resultsshow that,in about the year of2007,the human factors involving constructing ofmarine engineering and removal of artificial breeding raft frame in JiuLong Bay caused the direction and height of the wave into the bay changed,destroying thesediment balanced environment of the study area,in one side leading to the hesediment been washed up and transported in offshore directions,shaping thestorm-type beach profile,in the other side,resulting in beach erosion of the westernpart of the study area,the sediment was transported with the coastal current to the eastside.Human factors are the major factors causing the coastal erosion of the study area.According to the coastal erosion status quo,wave characteristics and sedimentmigration law of the study area,this paper has proposed the targeted protectivemeasures,a combination of approach embankment and breakwaters isrecommended,and at the same time appling artificial beach nourishment to seriouslyeroded area,the measure will achieve good results to prevent the erosion of the studyarea and restore the beach environment.