Evaluation of different erosion models for debris flow modeling

The shallow landslide-generated debris flow on hillside catchment plays a critical role in the change of landscape features caused by natural hazards. Numerous studies has been conducted on the analysis of the transported and deposited sediments by debris flows that were developed at the hillside catchments. Among these researches, the debris flow numerical modeling approach has an advantage of being able to predict and simulate the movement of the flow over irregular topographic terrains. A number of modeling approaches have been studied to explore the process of debris flow development. However, there are still a lot of uncertainties in the erosion-entrainment process, although several erosion models have been proposed to simulate debris flow. The objective of this study is to test and analyze several erosion models for debris flow simulation. Deb2D model, a two-dimensional debris flow simulation software based on quadtree-grid, is used to simulate the debris flow. The study case was 2011 Mt. Umyeon landslide in the Republic of Korea. The total debris flow volume, maximum velocity and inundated depth generated from Deb2D were compared with the field validation data. In particular, the spatial distribution of erosion depth was extracted from the LiDAR-based DEM data gauged before and after the event to compare the performance of the erosion model. The research showed each erosion model accuracy and shortcomings through comparison with field validation data.

Keywords : debris flow, numerical simulation, entrainment, erosion model, Deb2D