Comprehensive risk evaluation in Rapti Valley, Nepal: A multi-hazard approach

Abstract

While research on natural hazards in Nepal has primarily focused on the consequences of individual hazards within an area, it is also essential to analyze the probable occurrence of several types of natural hazards and their interaction, i.e., Multi-hazard assessment. In light of this, the study conducted a Multi-Hazard Risk Assessment of the proposed capital city of Lumbini province, which covers 14 wards from three municipalities. The four prevalent hazards in the area, i.e., flood, landslide, debris flow, and forest fire, have been considered in the study, which includes generating individual susceptibility maps using different geospatial and modeling techniques. The vulnerability and risk assessment was done on a ward level and considered physical, social, economic, and environmental vulnerability indicators. The results on the multi-hazard susceptibility map show that 29.36% of the area was at low susceptibility, while the medium and high zones comprised 46.16% and 24.46% of the total area, respectively. Wards 2, 3, and 7 of Rapti are highly vulnerable, while Ward 8 of Sitganga and Ward 9 of Rapti are the least vulnerable. Moreover, wards 1, 2, and 3 are at high risk to the vulnerability parameters, while ward 8 of Sitganga is at the least risk. The high-risk areas are on the foothills of the Siwalik range, which are prone to landslide, debris flow, and forest fire hazards, as well as are on the bank of West Rapti River, which marks them as potential flood hazard zones. The capital city of Lumbini province is fast developing. Therefore, the results derived from this study assist in identifying potential risk zones to consider while creating a master plan for the area.