Multi- Hazard Risk Assessment of Khimti Watershed
Date
2021-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Pulchowk Campus
Abstract
Many places of Nepal are vulnerable to multiple hazards. Past and recent evidences have shown
that the area near the hydropower areas is more vulnerable towards flooding and landslide. As
many hydropower structures are under construction near the Khimti region, studying the
vulnerability of this area is of great importance. The basin is vulnerable to flooding, landslide
and seismic hazards. This study therefore aimed to assess multi-hazard risk through integration
of individual hazard maps of flood, landslide and earthquake. This study utilized geographic
information system (GIS) in combination with Frequency Ratio Approach for landslide hazard
mapping. Flood vulnerability and risk was mapped by developing flood-inundation mapping
model in HEC-RAS. Earthquake hazard map was prepared using R-CRISIS tool. The multi-
hazard map was created using analytical hierarchy process for assigning weights to individual
hazard map (landslide, earthquake and flood). For assessing climate change impact on flood
inundation, future climate was projected using a set of five CMIP6 Global Circulation Models
(GCMs) under Shared Socio-economic Pathways (SSP) scenarios.
Eleven causative factors were identified and evaluated using GIS, and a landslide susceptibility
score was created based on each factor's prediction rate. Finally, a landslide susceptibility map
was created with the use of the landslide susceptibility index, and it was divided into four
categories (i.e., Low, Moderate, High and Very high). The areas under classified range Low,
Moderate, High, and Very High susceptibility zones, respectively, are 41.0%, 28.2%, 21.0%,
and 9.8%. Flood hazard map was prepared using depth grid for 100-year return period from
HEC-RAS. The obtained flood hazard map was divided into three categories (i.e., Low (< 1
m), Moderate (1 – 3 m) and High (> 3 m)) based on inundation depth. The areas under classified
range Low, Moderate, High zones, respectively, are 1.3 Km2
, 0.6 Km2
and 0.3 Km2
Description
Many places of Nepal are vulnerable to multiple hazards. Past and recent evidences have shown
that the area near the hydropower areas is more vulnerable towards flooding and landslide.
Keywords
Citation
MASTERS OF SCIENCE IN CLIMATE CHANGE AND DEVELOPMENT PROGRAMME