Loess erosion patterns on a cut-slope revealed by LiDAR scanning

Abstract

Erosion is a major environmental issue on the Chinese Loess Plateau. Although the erosion intensity on the plateau has generally decreased in recent years, ongoing mega-engineering projects continuously produce large, bare, and steep loess cut-slopes that are prone to erosion. Therefore, investigating loess erosion on cut-slopes in this region has practical importance. Multi-temporal high-resolution digital elevation model (DEM) analysis has been widely used to quantify surface erosion, but has not yet been applied to loess cut-slopes. This study aims to reveal the spatial and temporal patterns of loess erosion on an artificial cut-slope through the analysis of a time series of LiDAR scans. The results showed that the spatial distribution of loess erosion on the study cut-slope was constrained by three slope characteristics: slope material, slope structure, and slope hydrology. The highest erosion rates were observed in areas with paleosols, discontinuities, and water accumulation. In the temporal domain, the variation of the loess erosion rate with rainfall intensity could be described using a power function. Although this research only focused on one slope, findings suggest that it is possible to investigate the complex loess erosion on cut-slopes using state-of-the-art high-resolution remote sensing techniques such as LiDAR scanning. Our results provide useful information for soil conservation on similar engineering loess cut-slopes in the Loess Plateau.