Hydrology and sediment yield response to changes in land-use and climate in the Upper Blue Nile Basin, Ethiopia

Environmental components substantially affected by climate and environmental disruptions are watershed-scale hydrology and soil erosion. This research assessed the effects of scenario-based climate and land use land cover (LULC) changes on sediment and hydrology using dynamic conversion of land-uses and its effects (Dyna-CLUE) and soil and water assessment tool (SWAT) in Gumara watershed of Ethiopia. Climate change was analysed using GCM-RCMs outputs under SRES A1B and representative concentration pathways (RCP2.6, RCP4.5, and RCP8.5) from 2025-2099. Runoff, groundwater flow, lateral flow, and water yield decreased, whereas, evapotranspiration (ET) and sediment yield increased in both scenarios. Compared to LULC, climate change has a greater impact on reducing runoff (19-33.6%, 1.7-37.9%) and water yield (15.1-33.6%, 7.2-41.4%) in A1B and RCPs respectively. Rapid LULC conversion resulted in a significant increase in sediment yield up to 71.9% in A1B and 84.3% in RCPs.