Numerical Study Of The Reclamation Impact On The Hydrodynamic Environment In Tianjin Coastal Sea

The coastal cities have developed rapidly,both in economy and technology in a leading position,With more and more people moving into coastal cities,the reclamation projects become much more popular.The Large-scale reclamation projects have significantly impacted on the coastal marine environment which has attracted the attention of scholars while it solved the problem of land lacking effectively.This paper mainly illustrate the influences of Tianjin reclamation projects on the tidal current,tide,tide influx and water exchange of the coastal areas.Through field investigation,we found that the marine elements has changed very much.Therefore,this paper uses numerical simulation method to study the influences of Tianjin reclamation projects.Bohai bay has some features: complex coastline,extensive mud flat and complicated seafloor.This paper adopts FVCOM to research Bohai bay.The FVCOM has many advantages,such as triangular net,finite volume method and a new wetting and drying method.Those advantages can solve difficulties of Bohai bay.We verifies the model,learning the model is reliable.Then we select three periods,including 2005,2010 and 2015.The reason we select those periods is that coastline had obvious changes.Though the research we can draw a conclusion that the Tianjin reclamation projects bring the change of tide.M2 and S2 spread from Bohai bay outside to inside.Amplitude become maximum in Tianjin nearshore,epoch of partial tide from north to south growing lager;Influences of Tianjin reclamation on tidal current is complex.Because the large range of reclamation projects make tide current alongshoreflowing.During the rise and ebb,revering current is the southwest-northeast in the south Bohai sea,and it is southeast-northwest in the north Bohai sea.Residual current is dominated by the alongshore current.Residual current is affected by coastline;Tianjin reclamation projects make tide influx smaller.From 2005 to 2015,the tide influx is decreased year by year.Particularly,it is decreased more significantly in 2020.Tianjin reclamation have effect on Bohai Bay water exchange;It indicates that water exchange rate decreases in 2015 than that in 2005.In 2020,it takes 408 days which is more than 10 days in 2015 to reduce pollutants concentration by half.We can predict hydrodynamic force environment situation in the future,so that it is more easy to scientifically cognize and protect oceanic environment...