Quantitative evaluation of debris flow provenance erosion based on Airborne Lidar Technology

The material source is one of the three basic conditions for the formation of debris flow, and the change in erosion accumulation of the material source is an important index to measure the scale and frequency of debris flow. Currently, conventional techniques are still unable to achieve quantitative research on the change in source erosion accumulation. To solve this problem, this paper takes the gully debris flow at the back of the Qionghai water plant in Xichang City as an example, based on two periods of optical images and high-precision DEM (Digital Elevation Model) by LiDAR before and after the rainy season, carries out quantitative evaluation of debris flow provenance erosion. The results show that: the fire area of the basin is 65%, and there are slope erosion provenance, landslide provenance and gully accumulation sources in the basin. According to the superposition analysis of two high-precision DEM datasets, the source erosion amount of debris flow before and after the rainy season is 12209 cubic metres. The source erosion area is characterized by wide distribution, large number and scattered development. The debris flow is mainly caused by slope material source erosion, and the majority of the erosion thickness is within 0.5 m. Therefore, there will be high frequency debris flow in the future.