Risk Assessment of Single-Gully Debris Flow Based on Dynamic Changes in Provenance in the Wenchuan Earthquake Zone: A Case Study of the Qipan Gully

After the Wenchuan earthquake on 12 May 2008, a huge amount of loose deposits was generated mountain surface in zone, and vegetation severely damaged, providing rich source material for debris flow, greatly increasing danger. For many years, researchers have mainly considered recovery slope assessing risk flow post-earthquake. However, field investigations found that large amounts dynamic reserve materials gully an important impact risk. Thus, based survey data, this paper takes Qipan County as object uses multi-source multi-scale monitoring methods (Landsat series, Quickbird, Unmanned Air Vehicle) to analyze statistically study provenance both pre- post- earthquake. By comprehensively using game theory combination weighting cloud model, assessment model constructed evaluate from 2005 2019. The results show post-earthquake 7.7 times pre-earthquake, by 2019 had recovered pre-earthquake level. Based statistical estimation outbreak dredging blocking dam recorded relevant decreased about 781.3 × 104 m3 Compared with considering only, result is more realistic. are expected provide reference guidance faced projects high-seismic-intensity mountainous areas ensure safety people’s lives property effectively.