[A-HW22] River Channel Morphology, Water Resource Management, and Advanced Techniques

[AHW22-P10] Assessing debris flow risk in mudstone regions under climate change: integrating rainfall characteristics and spatial distribution

*Wen-Yung Chiu¹、Bing-Shyan Lin¹ (1.Feng Chia University)

キーワード：Flo-2D, Debris Flow, Climate Change, Risk Analysis

As global climate change intensifies, rainfall patterns are undergoing significant alterations, particularly in terms of abnormal dynamics in rainfall intensity and distribution. This study aims to estimate the impact of climate change on rainfall patterns and its influence on triggering debris flows. These changes pose severe challenges to slope stability in such areas and substantially increase the risk of debris flow disasters. In mudstone regions, due to the high content of fine-grained silt and clay, the soil structure exhibits low permeability, leading to high surface runoff rates. Consequently, these soils are among the most erosion-prone. Rainfall-induced erosion has a pronounced effect, and intense or short-duration concentrated rainfall events can easily trigger sediment transport and deposition, altering slope gradients. Over time, with repeated occurrences, the likelihood of debris flow events increases spatially, posing a direct threat to the safety of local residents and their property. This study selects potential debris flow streams in mudstone regions in Hualien County, south-eastern Taiwan as the research area. Using Flo-2D numerical simulation software to simulate hydrological and sediment transport analysis result for debris flow scenarios under different rainfall patterns. different rainfall intensity, duration, and spatial distribution and sediment transport processes. In addition, this study also conduct a comprehensive risk assessment to quantify the risk levels of debris flow hazards under different continuous repeated rainfall scenarios. By considering key factors such as local topography, slope gradient, flow path length, and vegetation cover, a risk zoning map will be developed to predict the potential affected areas and the severity of disaster impacts over time. This approach will help identify high-risk zones and provide targeted recommendations for disaster prevention and mitigation. Under the influence of climate change, future variations in rainfall patterns may further exacerbate debris flow risks which can provide long-term science-based disaster evacuation plan references for local governments.