Abstract:

A heavy rainfall was triggered in Wangmo County, Guizhou Province on June 5-6, 2011. A debris flow was broken out in Nabao gully in this area, and caused plenty of damage. This study analyzed the source, topography and rainfall conditions of debris flow, and revealed that the large intensity of rainfalls and the large proportion of slopes in the range of 30°-40° were the triggering reason of shallow landslides, and the landslides provided the solid sources of debris flow. The characteristics and dynamic parameters of the debris flow are concluded as follows: the debris flow is one of the less viscous debris flow; the peak discharge is 25 m³/s, and the total volume of debris flow is about 6,100 m³. The debris flow in Nabao gully was induced by shallow landslide. In the light of the characteristics of Nabao gully, the local government and resident should attach great importance to these and take the corresponding biological and engineering measures to prevent debris flow.

Key words: Nabao gully, debris flow, rainfall, landslide, gradient