Geo-Environmental Impact Assessment Using Integrated GIS and Remote Sensing Technique: a Case Study on the Halele-Werabesa Stage I Hydropower Plant, West-Showa Jimma Zone, Oromia, Ethiopia
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Date
2014-05-05
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Addis Ababa University
Abstract
Geo-environmental impact assessment is often evaluated systematically in order to assess the nature of hazards and their potential damage to human life, land, buildings and other property. This study reports geo-environmental impact of Halele - Werabesa stage I dam reservoir and its surrounding environment located within Omo-Gibe Basin 170km south east of Addis Ababa. The main objective of the present study was to assess the potential Geo-environmental impact using integrated methods of GIS and remote sensing. To end up with mass wastage risk map of the study area two models were devised namely landslide susceptibility and soil erosion risk models. Seven landslide-controlling parameters namely lithology, slope, aspect, drainage density, lineament density, soil and land use were identified in order to detect Landslide susceptibility risk using logistic regression model. As result landslide susceptibility of the study area varies from very low (28.3%), low (40.8%), moderate (21.5%), high (7.8%) and very high (1.6%). This is mainly the result of slope and soil type in the area. The soil erosion risk analysis was also conducted using RUSEL model in GIS environment. It is conducted using R, K, C, P and LS factors. Result of the analysis shows the total amount of soil loss in the study area is about 294 tons per year from a total area of 7197.8 km2. Most of watershed area falls within the low soil erosion risk category (76.1%) which is mostly seen in the west and central parts of the watershed. While 0.6 % of the watershed is categorized as very high soil erosion risk area. By combining the landslide susceptibility and soil erosion risk map of the study area mass wastage map is prepared; which shows area which needs conservation priority. The results indicated that 78.8%, 16.2%, 4.3%, 0.7%, of the study area was under low, moderate, high and very high mass wastage risks, respectively. Since 5% of the study area is under high and very high risk these areas need conservation priority.
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GEIA, Landslide Susceptibility, Logistic Regression, Mass Wastage, RUSEL