A New Concept of Moraine-Supplied Debris Flow Prevention in Alpine Area, Moxi Basin, SW China

Abstract

It is found that there are large quantities of debris flows in the alpine area with the moraine as their loose source in southwestern China. Since the longitudinal slope of such debris flow gully is extremely steep, it is hard to carry out the engineering to control the debris flow in the midstream and the upstream of the basin. Besides, when the debris flows run out, they are in high speed, with destructive force and causing hazards rapidly without any warning. On analyzing the formation of this type of debris flow developed in the alpine area in southwestern China, this paper aims to find a new way to reducing the hazards caused by this type of debris flow, and proposes the “Key Section Prevention” concept model. Then, this paper selects Huangbengliu—one of the branches at the left bank of Hailuo Valley in Moxi basin as the study site, and based on the survey, the “Key Section” concept is applied to guide the design of the mitigation plan. With new design conception, this engineering successfully defends two debris flow events in 2010, and avoids the casualty of 30 local persons and the economic losses of 8 million Yuan. It proves to be useful to prevent this type of debris flow hazard in the alpine area by adopting the “Key Section” concept model. The findings can be useful for the prevention of the moraine-supplied debris flow in Moxi Basin; meanwhile, they can offer a new idea for the mitigation of this type of debris flow hazard in southwestern China.