Cause of Formation of Increased Flood Peak at Huayuankou during Regulated Discharge Regime of the Yellow River in 2010

The paper analyzes the phenomenon of increment of flood peak occurred at Huayuankou Station during the regulated discharge regime of the Yellow River in 2010.The outcomes show that a) the main reason of increased flood peak is that the coarse sediment has deposited in the widened river section of Tiexie-Lucun,formed a temporary submerged sand dam and caused the increase of storage of the upper stream during flood.The sand dam has been washed out under the continuous action of flow,causing the increase of discharge of Lucun Station and;b) it scours the channel along the river,velocity increases gradually and makes the discharge further increase during the process of flood wave moving towards the downstream.