earticle

영어

In Korea, where 63% of the land is mountainous, damage caused by shallow landslides is increasing annually. Therefore, it is crucial to evaluate shallow landslide and debris flow risks at the small mountain watershed scale and devise effective mitigation measures. This study assessed the potential for shallow landslide initiation and debris flow extent in a 16-ha small mountain watershed in Mungyeong-si, Gyeongsangbuk-do, using physics-based models, and evaluated the impact of check dam installation on damage reduction. TRIGRS (USGS) was employed for landslide simulation and RAMMS (WSL) for debris flow simulation. Both models used a 5-m DEM, and model parameters were estimated based on field measurements and conditions of nearby affected watersheds. TRIGRS simulation results identified 17% of the watershed as unstable (FS < 1), and potential collapse points were selected by comparing with the landslide hazard map. RAMMS simulations based on these points showed a debris flow area of 10.43 ha without a check dam, which decreased to 8.37 ha with the dam installed. Notably, debris flow impact downstream of the check dam was reduced by 78% after installation, significantly mitigating risk to nearby infrastructure. This study empirically examines the applicability of a physics-based model and the mitigation effect of check dams, and it is expected to serve as foundational data for planning related to mountain sediment disasters.