Numerical Study On Hydrodynamic And Water Exchange Features Caused By Reclamation Project Around The Bohai Bay

The coastal area is an important interface between land and sea,which has great ecological and economic value.The Bohai Bay is one of the three gulfs of the Bohai Sea,and the coastal area of the Bohai Bay is the concentrated area of three provincial key ports?industrial parks?sea-related projects for Hebei?Tianjin and Shandong.Recent years,a series of land reclamation projects were implemented in the Bohai Bay,land reclamation project would have an impact on tidal flow and water exchange capacity of the Bohai Bay,then influence the marine ecosystem's ability to regulate itself ? self purification capacity ? ecological environment of coastal water,thus,to study the influence of land reclamation project on the tidal flow and water exchange of sea water in the Bohai Bay is very necessary.Based on the ROMS model,the three dimensional hydrodynamic model of the Bohai Bay was established,the parameters of the model were calibrated,and the model was verified according to the measured data in the Bohai Bay,which would provide support for the further analysis of tidal flow and water exchange in the Bohai Bay.Using the verified three dimensional hydrodynamic model of the Bohai Bay,the tidal current fields under the Bohai Bay shoreline in 2003?2010 were simulated,and the nested grid was used to finely simulate the tidal current fields near the Tianjin Port in2003? 2010,the effect of land reclamation on the flow fields of the Bohai Bay was analyzed,tidal prism of the Bohai Bay was also calculated,the results show that land reclamation project weakens hydrodynamic feature of the Bohai Bay overall,the maximum flow rates of the sea between northeastern Dongjiang Port and Hangu ?northern Nanjiang Port?near the Lingang industrial area?near the Nan Port reduce 0.1 ~0.18m/s?0.05 ~ 0.1m/s?0.1 ~ 0.18m/s?0.1 ~ 0.15m/s respectively during rising tide,reduce 0.1 ~ 0.15m/s?0.05 ~ 0.1m/s?0.1 ~0.15m/s?0.1 ~ 0.15m/s respectively during ebb tide,tidal prism of the Bohai Bay in 2010 decreases 6.56% compared with tidal prism in 2003.Based on the convection and diffusion model,water exchange of eight coastal functionally planned areas of the Tianjin Port was studied with the further application of relation matrix,water exchanges of each area in 2003 ? 2010 were compared and analyzed,the effect of land reclamation project on the water exchange near the Tianjin Port was analyzed,the results show that the land reclamation project weakens water exchange near the Tianjin Port,on the 30 th day,the water exchange capacity of northeastarea of Dongjiang Port A2?Tianjin Dashentang Oyster Reef National Marine Special Reserve A6?north central Bohai shipping area A7 don't change much,but the water exchange capacity of tourism and entertainment area A1 decreases 22.17%,the water exchange capacity of Tianjin harbor A3 decreases 14.85%,the water exchange capacity of shipping area of Lingang industrial area A4 decreases 10.01%,the water exchange capacity of Nangang discharge port and shipping area A5 decreases 10.77%,the water exchange capacity of agricultural and fishery area in southeastern Tianjin A8 decreases3.29%,and the causes of water exchange change were analyzed,which would provide support for the further analysis of the diffusion of pollutants?change of water quality and ecological environment in the Bohai Bay.