Landslide hazard zonation around Gilgel Gibe-II Hydroelectric project, Southwestern Ethiopia

The present study was carried out along the newly constructed road from Fofa town to Gilgel Gibe-II powerhouse in South western Ethiopia. In this study, an attempt has been made to provide information on the landslide hazard zones present along the new road. In order to delineate the hazardous zones the landslide hazard evaluation factor rating scheme (LHEF) proposed by Anbalagan (1992) has been utilized. The LHEF rating scheme is based on an empirical approach which combines past experience gained from the study of causative factors and their impact on landslides with conditions anticipated in the area of study. For LHEF rating scheme data on major inherent causative factors of slope instability such as geology, slope morphometry, relative relief, land use and land cover and ground water conditions has been collected. Based on the evaluation values, the slopes in the study area have been classified for landslide potential as; High Hazard, Moderate Hazard and Low Hazard. The results of the present study indicate that 54% of the slopes in the study area fall in High Hazard, 34% in the Moderate Hazard and 12% in the Low Hazard zones. Thus, the Landslide Hazard Zonation shows that chances of slope failures are high in the study area.