[M-IS04] Extreme Weather and Water-Related Disasters in Asia

[MIS04-07] Hydro-meteorological and Damage Characteristics of September 2024 Flood in the Bagmati River basin of Nepal

★Invited Papers

*Badri Bhakta Shrestha¹、Mohamed Rasmy¹、Katsunori Tamakawa¹、Sauhardra Joshi²、Daisuke Kuribayashi¹ (1.International Centre for Water Hazard and Risk Management, Public Works Research Institute, Tsukuba, Japan、2.Department of Hydrology and Meteorology, Kathmandu, Nepal)

キーワード：2024 Nepal flood, extreme flood event, flood inundation, exposure assessment, RRI model, GEE

Recently, extreme flood events frequently occur in various part of the world, resulting huge economical loss and threatening human lives. In September 2024, Nepal experienced the severe flood disasters, claiming at least 249 lives, with 18 people missing and 178 injured, and economical loss approximately 46.6 billion Nepalese Rupees. In this context, this study aimed to investigate hydro-meteorological and damage characteristics of September 2024 flood in the Bagmati River basin of Nepal, based on hydrologic-hydraulic model outputs and data and information collected from the field surveys. To predict flood inundation characteristics, we employed the Rainfall-Runoff-Inundation model (RRI model). To understand the characteristics of flood and damage, we also conducted field and questionnaire surveys in the flood affected areas of the Bagmati River basin in November 2024. Furthermore, we also conducted rapid flood exposure assessment for September 2024 flood using the flood simulation results, focusing on buildings, people and land use/land cover areas. The Google Earth engine platform was used to assess flood exposures. The flood simulation results show that large areas were inundated with greater flood depth in the low-land Tarai areas (southern part of the basin). The temporary type houses, rice crop areas, and sugarcane areas were severely affected by the flood in the Tarai areas. The flooding was also severe along the Bagmati River and its tributaries in the Kathmandu valley, and based on field surveys, it was revealed that the houses along these rivers in the Kathmandu valley were directly affected by floodwaters, and that the household contents were more significantly affected than the houses themselves. The results of this study provide scientific insights to understand characteristics of extreme flood event and associated exposures. The results can be useful for planning and implementing flood prevention measures and policies required for the reduction of flood damage and loss.


Acknowledgments: This research was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 24K07692.