Near shore waves,long-shore currents and sediment transport along micro-tidal beaches,central west coast of India

(整期优先)网络出版时间:2014-03-13
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Coastlinesareundergoingconstantgeomorphologicchangeswithrespecttotheincidentwaveclimate.Basedonwavesmeasuredat9mwaterdepth,simulationofnearshorewavetransformationisdoneusingREFDIF-1numericalmodelandthenearshorebreakerparametersareestimatedattwomicro-tidalbeachesalongcentralwestcoastofIndia.Modelresultsarevalidatedwithmeasuredvalues.Fromthebreakerparameters,long-shorecurrentandlong-shoresedimenttransportrates(LSTR)arecomputedbyusingsemi-empiricalequations.Estimatedlong-shorecurrentandLSTRareshowingdramaticvariationswithrespecttoseasons.PredominantdirectionofLSTRisobservedtowardsnorthsincetheapproachwavesarefromsouth-westdirectionduringpre-monsoonandpostmonsoon.Duringmonsoonseason,wavesarefromwestsouth-westandresultedinsoutherlytransport.TheestimatedannualnetandgrossLSTRbyCambridgeEnvironmentalResearchConsultants(CERC)attwolocationsareinthesameorderwhereasLSTRestimatedbyWalton&BrunoandKamphuisequationsareshowingdifferentestimationsbecauseofdifferenceinsurf-zonewidthandforeshoreslopebetweenthetwolocations.Formicro-tidalbeacheswithlengthlessthan6km,KamphuisequationisgivingagreeableestimationofLSTR.SensitivityanalysisofLSTRestimateshowsthatcoastalinclinationistheprominentfactorindeterminingLSTRthanincidentwaveangle.