Risk Assessment of "2007-5-20" debris flow in Mohong Gully of Leibo County, Sichuan Province

On May 20, 2007, the debris-flow disaster took place in Mohong Gully of Leibo County, Sichuan Province. It caused a direct economic property loss around (sic) 1,000,000, 7 persons died and 3 persons disappeared. After field investigation, the formation conditions of debris flow in Mohong Gully, including the characteristics of soil, climate and rainfall, were analyzed. The main cause to the "5-20" debris flow was the heavy rainstorm. The risk assessment of debris flow is analyzed on the base of hazard and vulnerability assessment. And it is concludes that the risk degree of "5-20" debris flow is 0.43, which attributes to high risk degree. According to the natural and economical conditions of Mohong basin, the comsponding countermeasure is putting forward.