Quantification of mudcracks-driven erosion using terrestrial laser scanning in laboratory runoff experiment

Abstract

Understanding rill development and erosion rates is crucial for understanding changes in hillslope morphology and soil erosion. Mudcracks, a widely distributed feature on the land surface, play an important role in erosion, but the quantitative relationship between mudcracks and erosion has seldom been reported. Thanks to advances in terrestrial laser scanning (TLS, also known as terrestrial LiDAR), topographic changes can be observed at high resolution. This study is designed to quantify the effects of mudcracks on erosion. Mudstone specimens with and without mudcracks were analyzed. Using TLS, we quantified the millimeter-scale effects of mudcracks on slope erosion and rill development in laboratory experiments with well-controlled samples and water discharge. The point cloud data collected by TLS were then converted to digital elevation models (DEMs) for DEM of difference (DoD) analysis. The results show that mudcracks facilitate rill development. In the early stage of the experiment, the erosion depth of the cracked mudstone is twice that of the surface without cracks, and the total erosion amount is more than twice. During the experiments, the dominant erosion pattern changes from sheet erosion to rill erosion and then lateral erosion. Moreover, our study highlights the potential of TLS and DoD for high-resolution spatio-temporal topographic surveys to identify and characterize micro-relief-induced erosion.