Research Of The Hydrodynamic Environment Variation In Bohai Sea Influenced By Reclamation With FVCOM

Land reclamation is an important way to cope with the growing demand for land resources in the coastal areas,and plays an important role in social and economic development.However,land reclamation changes natural shorelines and then results in changes of the hydrodynamic and ecological environment.Therefore,scientific evaluation of the impact of land reclamation on coastal dynamics is of great significance to rationally plan and regulate the development of coastal resources and protect the coastal ecological environment.Given reclamation activities in the Bohai Sea,?Finite Volume Coastal Ocean Model?FVCOM is used to simulate the hydrodynamics in the Bohai Sea before and after the land reclamation to analyze the influence of the reclamation on the hydrodynamic environment.Firstly,the model is validated using observations in the Bohai Sea before and after the land reclamation.It was found that model results agreed well with in-situ observations.So the hydrodynamic model could be used for simulations of different schemes.Then,different from the analysis of the cumulative effect of reclamation according to the time of reclamation,the reclamation area is divided into three parts according to the location of the reclamation.And five different schemes are designed to simulate the hydrodynamic environment influenced by different reclamation parts.In comparison with the model results before land reclamation,the amplitude of the M₂ tide increased in the Bohai Bay after the reclamation,but decreased in the Laizhou Bay and even decreased significantly in the north of the Caofeidian.In addition,the location of the amphidromic point of M₂ near the Yellow River moves towards the northeast.Different from the M₂ tide,the amplitude of the K₁ tide increased in the whole Bohai Sea,while the location of the amphidromic point of K₁ does not change obviously.At the same time,the area of diurnal and irregular diurnal tidal type adjacent to the Yellow River estuary expanded.Among the reclamation parts,the reclamation around Tianjin Port has made the greatest contribution to the tidal changes.According to the analysis of simulated tidal current,the influence of the reclamation on the tidal current is mainly confined in the vicinity of the reclamation area.The tidal current characteristics around the reclamation area have changed and show different influences at different locations.After the land reclamation,the maximum probale flood decreased in the Bohai Bay and Laizhou Bay but increased in the middle of Bohai Sea.The residual tidal current changed complexly after the land reclamation.Among the reclamation parts,the reclamation around Tianjin Port has made the greatest contribution to the tidal current changes.With the change of tide and tidal current,the tidal energy flux density in the Bohai Sea has decreased,especially around Tianjin Port.This indicates that the reclamation locating facing the bay-mouth makes significant influence on the hydrodynamic,and its influence should be foused on in the future reclamation planning.