The sediment deposited in channel may cause sudden siltation that is serious effect to the navigation and operation of harbor. Reasonable simulation of sediment transport process due to typhoon is significant to predict the sudden siltation of harbor and channel accurately. In this paper, a series of numerical model is developed to simulate the sediment sudden siltation of channel in Oujiang estuary during typhoon, and the effect of channel protection project is studied according to the simulation.
There are above 6.5 times typhoons annually influenced the Yangtze estuary and east sea areas of Zhejiang Province, China, according to the statistics from 1949 to 2005. During typhoon attacking, the sediment on beach in nearshore zone is easily suspended and transported by large wave and storm surge, which may cause sudden siltation in channel and impact the navigation and operation. Oujiang estuary in Zhejiang province, China, is attacked frequently by typhoon, in which the sediment siltation of channel is serious. Therefore, some engineering measures preventing from siltation have to be considered. How to simulate the sediment sudden siltation of channel due to typhoon and storm surge process, and how about the effects of the protection project near channel will be all that we are interesting in. Oujiang is a strong estuary that tides can reach up to 78 km upstream form its mouth, with a river basin of 1.8×104 km2. According to observational data, the average total amount of fresh water discharge is 470m3/s, and the suspend load transport amount is about 2.051×106 t a year. The Oujiang estuary is dominated by semidiurnal tides with the average tidal range of over 4 m and the maximum tidal range of over 7 m. Tidal currents in the estuary belong to shallow water semidiurnal tidal currents.