Extreme rainfall events increasingly trigger complex multi-hazards in mountainous watersheds, where severe flooding is compounded by massive sediment transport and driftwood dynamics. Simulating these cascading phenomena is highly challenging due to the intricate interactions spanning multiple spatial and temporal scales.

This talk presents an integrated, process-based modeling framework designed to simulate the entire chain of water, sediment, and driftwood disasters at a catchment scale. The framework couples a catchment-scale rainfall-induced sediment runoff and production model (RSR-Model) with a detailed 2-D depth-integrated hydro-morphodynamic inundation model. By routing wood pieces through a novel wood-convection equation, the model explicitly accounts for driftwood transport and accumulation at bridges.

The predictive capability and practical utility of these approaches are demonstrated through real-world application cases, discussing how integrated process-based modeling overcomes upstream boundary condition uncertainties to significantly improve the simulation’s accuracy.

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Menglu Qin (秦 梦露) is a Research Specialist at the International Centre for Water Hazard and Risk Management (ICHARM) under the Public Works Research Institute (PWRI) in Japan, and an Adjunct Associate Professor at the National Graduate Institute for Policy Studies (GRIPS). She is also a member of the international SATREPS PREVENIR project, where her current work focuses on integrating a sewage network system into the Rainfall-Runoff-Inundation (RRI) model to adapt it for advanced urban flood modeling. Her broader research centers on the development and application of advanced numerical models for water-related disasters, specifically focusing on physics-based, process-oriented modeling of catchment runoff, catchment-scale sediment production and transport, hillslope erosion, and driftwood dynamics. Currently, Dr. Qin is developing a basin-scale Rainfall-induced Sediment Production and Runoff Model (RSR-model) to assess the multi-composited sediment-related hazards in catchments triggered by extreme rainfall events. Her work provides insights into the interactions and transformations among landslides, debris flows, and floods with massive sediment and driftwood within a mountain catchment, enhancing our understanding of water-related hazards under climate change.