Numerical simulation of oil spill transport under the effect of dredging projects in the north part of the Xiaogan Island of Zhoushan

Abstract

In the present study, a two-dimensional tidal current and oil spill numerical model was established by using the software MIKE21 to simulate the transport and spread of the oil spill in the area of the Xiaogan Island of Zhoushan, Zhejiang Province. After validated by the field measurements, the model was applied to simulate the current and the spread of the oil spill before and after the dredging project. The results showed that: The oil particles diffused faster under the calm wind, with a spread area of 751.55 km2 after 72 hours. The diffusion area and the time for the particles reached to the sensitive points were obviously different between the flood and ebb tide, and the diffusion area was larger during the flood tide. The duration of the particles reached to the sensitive points was shorter during the ebb tide. Under the wind directions of NW, NNW and N during flood tide, the oil particles adhered to the south breakwater and the surrounding area was not affected by the oil spill. The current velocities for both flood and ebb tide were decreased after the project. The decreasing of the current velocity ranged from 0.05 to 0.2 m/s during the flood tide, and 0.1 to 0.15 m/s during the ebb tide. It can be concluded that wind is beneficial for the water environment.