Mapping of Soil Erosion Hotspot Areas Using GIS Based-MCDA Techniques in South Gondar Zone, Amhara Region, Ethiopia

In the highlands of the country in which the study area found was affected by soil erosion and desertification. This problem on the environment includes loss of soil fertility, reduction of the depth of water body (lakes, ponds, reservoirs etc), high water turbidity, flood hazard problems etc. This study focus on mapping of soil erosion prone areas in South Gondar zone (area: 14604 sq km), which comprises of Blue Nile river basin and Tekeze river basins. This study leads where the most effective soil conservation strategies should focus in the area. Based on GIS with the integration of the Multi Criteria Decision Analysis (MCDA), an attempt was made to combine a set of factors (Land use, Soil, Slope, Topographic Wetness Index, Stream Power Index, Elevation, and Curvature) to have a fruitful decision to fulfil to the stated objective. Raster based pairwise comparison method considering seven soil erosion motivating parameters have been done in Arc GIS environments. MCDA is used to quantify the raster based qualitative spatial erosion hotspot area which produced through pairwise comparison. Raster based spatial model tells that out of total watershed area, 39.31 sq km (0.27%), 33.40 sq km (0.23%), 2358.12 sq km (16.15%), 11027.76 sq km (75.51%) and 1145.60 sq km (7.84%) areas are very high, High, Medium, Low and Very low prone to soil erosion respectively. This study will serve as insight to Basins/watershed decision maker and planners to alleviate soil erosion problems and its related hazards.