Study on tidal current and sediment environments in Oujiang estuary caused by the entrance channel regulation project

This paper analyzes the features of tidal currents,sediment transport and seabed evolution and the causes of sediment siltation in the entrance channel of the Oujiang estuary based on in-situ data.A mathematical model of wave,tidal currents and sediment transport was developed to calculate the sediment siltation and sudden sedimentation caused by typhoon in the channel at the completion stage of phase II regulation project under normal year conditions and to evaluate the project's impacts on hydrodynamic and sediment environments.The results show that the phase II project has little impact on its surrounding hydrodynamic and sediment environments and that sediment siltation in the channel are mainly caused by sudden sedimentation during rough climate such as typhoon.Actually this regulation project can reduce sediment siltation if the Sanjiaosha shoal is taken under control.The scheme of constructing the north jetty and west jetty on this shoal can produce an obvious effect in sedimentation reduction.