Soil erosion risk analysis and mapping for conservation planning at Mihtsab-Azmati micro-dam watershed, Northern Ethiopia

Abstract

This study was conducted to quantify, analyze and map soil erosion risk areas using remotely sensed data and GIS-based Revised Universal Soil Loss Equation (RUSLE) model at Mihtsab-Azmati Irrigation Dam Watershed, Northern Ethiopia. Based on the result, the watershed has potential soil erosion risk which ranges from 0 ton hectare⁻¹ year⁻¹ to 2980.12 ton hectare⁻¹ year⁻¹ with an average annual soil erosion rate of 110.06 ton hectare⁻¹ year⁻¹. From the entire watershed area, only 27% of it has a soil loss a value less than 15 ton hectare⁻¹ year⁻¹ which is relatively categorized under low soil erosion risk, while the remaining area (73%) experiences moderate to very high soil loss rates. A large area (50.7%) is under high to very high soil loss (>50 ton hectare⁻¹ year⁻¹). The majority of the study watershed area experiences a very high soil erosion rate and this could be a major threat to the new irrigation dam constructed at the outlet of the watershed due to the sedimentation problem, which could decrease the economic lifespan of the dam. Hence, from the conservation perspective, a large proportion of the upper watershed area requires immediate and appropriate soil conservation measures.