Formation and cause analysis of scouring funnel in front of dam in model of Three Gorges project

Based on the data, which represent the variation of the scouring funnel from the storage to the balance of the reservoir in the physical model of Three Gorges,the results that the forming process of the scouring funnel is composed of silting,scouring and basic balance are obtained by this paper.The reasons caused the funnel variation are discussed.The formula that expresses the whole process of souring funnel is presented.