Landslide Assessment, Susceptibility Analysis and Recommendation of Remedial Measures for Jimma-Chida Road Segment, South-West Ethiopia
No Thumbnail Available
Date
2024-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In Ethiopia, landslides, mostly demonstrated as rock fall, earth slide, debris, and mudflow,
are prevalent in the central, south-southwest, and north-northwest highlands, especially
after intense rainy season. Jimma-Chida road section which is studied in this paper is
located in southern highlands and lies in Gibe and Gojeb River Basins where landslide
incidence occurred frequently.
This work studied the active landslide areas along Jimma-Chida road by assessing their
features, failure mechanism and extent of the landslides. Landslide susceptibility map is
produced by weighting factors that contribute to the landslide using Analytical Hierarchy
Process(AHP) method and integrating it with the existing landslide inventory data. For
this purpose, key factors (lithology, elevation, rainfall, slope, slope aspect, land use/ cover,
distance to stream, distance to road and curvature) are considered and weighted after
dividing into sub-factors using AHP. Then the causative factor layers are overlaid using
weighted overlay technique in ArcGIS environment to produce the landslide susceptibility
map.
From the assessment of the existing landslide it is revealed that slope angle (90-140), slope
aspect(Northwest), elevation (2388-2732 m), curvature(flat), lithology (residual soil of
upper basalt flow), distance to stream (50 m), distance to road (50 m), land use/cover
(crops) and rainfall (1600-1675 mm) have higher contribution for the occurrence of the
active landslide. Based on AHP for landslide susceptibility map, distance to the stream,
distance to the road and rainfall are the most contributing factors with weight 0.203,0.197
and 0.199, respectively. The other influential factor is lithology with weight of 0.167,
followed by slope angle, aspect, elevation, curvature, land use/cover with the weight
0.073,0.023,0.023 and 0.059, respectively. The landslide susceptibility map concludes that
Jimma-Chida road section is classified as low (32.23%), moderate (62.87%), high
(4.89%), and very low and very high susceptibility zones are covered a very small and
localized areas.
Finally, modification of the slope geometry, provision of both surface and sub-surface
drainage, provision of retaining structure and internal reinforcement of slope are
recommended as a preliminary remedial measure for the area affected by landslide.
Description
Keywords
Landslide Susceptibility Map, ArcGIS, Analytic Hierarchy Process (AHP)