Assessment of the combined effects of land use/land cover and climate change on soil erosion in the Sile watershed, Ethiopian Rift Valley Lakes Basin

The combined impacts of land use/land cover (LULC) changes and climate change are significantly affecting soil and water ecologies, calling for proper natural resource management. The aims of this study were to assess the LULC dynamics between 1987 and 2050 and estimate the impact of LULC and climate changes (under two climate scenarios (RCP4.5 & RCP8.5)) on soil erosion rate in Sile watershed, Ethiopian rift valley lakes basin (ERVLB). A supervised method with maximum likelihood classification was applied in the ERDAS Imagine software for assessing the LULC of 1987, 2003, and 2020. A classified past LULC map serves as a baseline to predict 2050 LULC by considering different driver variables using Multi-Layer Perceptron Neural Network and Cellular Automata-Markov Chain Model integrated with TerrSet software. A revised universal soil loss equation model (RUSLE) has been used to compute an input parameter in ArcGIS to estimate the rate of soil loss. The input parameters were erosivity (R-factor), soil erodibility (K-factor), topography (LS-factor), conservation practice (P-factor), and cover (C-factor). The findings revealed that with the business-as-usual scenario, the substantial LULC alteration will be prolonged over the coming several years. The average soil loss under the RCP4.5 and RCP8.5 scenarios with a future 2050 LULC was predicted to be 56.48 t-ha-1 year-1 and 57.11 t-ha-1 year-1 and then it will be expected to increase 36.40% and 38.19%, respectively. In order to sustainably manage the natural resources, interventions in prioritized sub-watersheds have been suggested at present and for the future. Additionally, it needs ecological sound conservation policies and strategies to mitigate the adverse impacts of climate change on soil erosion.