Soil erosion and sediment export analysis for watershed management options in Fakisi watershed of the Abbay basin of Ethiopia

Abstract

Soil erosion by water is one of the major environmental threats and it not only decreases agricultural productivity but also reduces water availability. This study aimed to estimate soil erosion and sediment yield and prioritize sub-watersheds for management options with RUSLE methodology in the Fakisi watershed, Northwestern Ethiopian highlands. Digital topography, rainfall, land cover, land management, and soil datasets were used to develop RUSLE model parameters. The study revealed that 339,031 tons of soil was lost annually and the mean soil loss was 35 t ha− 1 yr−1. Severe to extremely severe erosion was observed at 14.9 % of the watershed which accounted for 58 % of the total soil loss. The sediment delivery ratio (SDR) of the watershed was between 0.17–0.43 and the mean annual sediment yield was estimated at 27.2 t ha−1 yr−1. The sensitivity analysis revealed that soil erodibility and land management were the factors most contributing to the soil erosion processes. Sub-watersheds (SW9, SW6, SW10, SW7, and SW8) accounted for 72.4 % of the total erosion and covered 56 % of the overall watershed. These sub-watersheds were designated as significant erosion zones and recommended to implement integrated soil conservation interventions to deter the high soil loss and sediment yield.

Keywords

• Priority for conservation
• Remote sensing
• SDR
• Sediment yield
• Sensitivity analysis
• Soil erosion