Estimating Gully Erosion Induced by Heavy Rainfall Events Using Stereoscopic Imagery and UAV LiDAR

Abstract

Highlights: We developed a large-scale erosion estimation method that fuses data from Chinese Gaofen-series high-resolution satellites and UAVs. Analyze and discuss the far-reaching impacts of anthropogenic and natural factors on soil conservation across the Loess Plateau. What are the main findings? Using multi-source high-resolution remote sensing data, we quantitatively assessed the impact of heavy precipitation on erosion and established a large-scale, generalizable methodology. Using multi-source high-resolution datasets, we quantitatively assessed how natural processes and human activities influence erosion trends. What is the implication of the main finding? We developed a systematic, high-precision erosion-rate analysis method that integrates China’s Gaofen-series satellites with UAV observations, is scalable to large areas, and enables a systematic assessment of how precipitation events affect erosion rates on the Loess Plateau. We elucidated the causes of soil erosion under the combined effects of human and natural factors and proposed methodological guidelines. Gully erosion, driven by the interplay of natural processes and human activities, results in severe soil degradation and landscape alteration, yet approaches for accurately quantifying erosion triggered by extreme precipitation using multi-source high-resolution remote sensing remain limited. This study first extracted digital surface models (DSM) for the years 2014 and 2024 using Ziyuan-3 and GaoFen-7 satellite stereo imagery, respectively. Subsequently, the DSM was calibrated using high-resolution unmanned aerial vehicle photogrammetry data to enhance elevation accuracy. Based on the corrected DSMs, gully erosion depths from 2014 to 2024 were quantified. Erosion patches were identified through a deep learning framework applied to GaoFen-1 and GaoFen-2 imagery. The analysis further explored the influences of natural processes and anthropogenic activities on elevation changes within the gully erosion watershed. Topographic monitoring in the Sandu River watershed revealed a net elevation loss of 2.6 m over 2014–2024, with erosion depths up to 8 m in some sub-watersheds. Elevation changes are primarily driven by extreme precipitation-induced erosion alongside human activities, resulting in substantial spatial variability in surface lowering across the watershed. This approach provides a refined assessment of the spatial and temporal evolution of gully erosion, offering valuable insights for soil conservation and sustainable land management strategies in the Loess Plateau region.