Impacts of integrated watershed management practices on soil loss and sediment yield in the Fettam watershed, Ethiopian Highlands

Abstract

Integrated watershed management (IWM) has been practiced in Ethiopia to reduce soil and sediment loss since the 1980s. Hence, this study aimed to evaluate the impacts of an IWM program in mitigating soil loss and sediment yield in the Fettam River watershed. The integrated application of physical, biological, and agronomic watershed management measures at the micro-watershed level altered the dynamics of soil and sediment loss. The annual average soil loss rate was estimated by integrating the five dominant parameters within a raster-pixel-based GIS and remote sensing framework applied to the RUSLE model. Inputs of the GIS layer, such as soil erodibility (K), rainfall erosivity (R), topography (LS), cover and management (C), and watershed support practice (P) factors, were calculated in the Ethiopian context. The results revealed that IWM practices positively contributed to reducing soil erosion and sediment yield rates over the past three decades. The annual soil loss rate in the watershed decreased by 43.5%, from 22.1 t ha⁻¹ yr⁻¹ in 1991 to 12.5 t ha⁻¹ yr⁻¹ in 2023, with intermediate rates of 18.7 and 16.5 t ha⁻¹ yr⁻¹ recorded in 2001 and 2014, respectively. The annual average sediment yield declined by 39.6%, from 19.4 t ha⁻¹ yr⁻¹ in 1991 to 11.7 t ha⁻¹ yr⁻¹ in 2023, with intermediate values of 17.5 and 14.7 t ha⁻¹ yr⁻¹ recorded in 2001 and 2014, respectively. The results indicate that roughly 96% of the watershed area is within tolerable (0–5 t ha⁻¹ yr⁻¹) erosion levels, whereas an estimated less than 3.5% shows moderate susceptibility (10–25 t ha⁻¹ yr⁻¹) and about 0.5% is highly (> 25 t ha⁻¹ yr⁻¹) susceptible to severe erosion. Enhancement of vegetation coverage in both natural and plantation forests from 5,459 ha (5.1%) in 1991 to 11,248 ha (10.3%) in 2023 at the expense of cultivated land, grazing land, and shrub land was observed. The findings highlight the significant contribution of IWM practices in reducing soil erosion and sediment export within the watershed. The study provides practical insights for sustainable watershed management and targeted conservation planning by identifying the upstream and downstream sections as priority areas requiring strengthened conservation measures compared with the relatively stable midstream areas.

The authors' abstract, as published at the source. Discover Sustainability, 2026 · DOI ↗