Prioritization of sediment yield at sub-watershed level using swat model in Finca'aa watershed, Abay Basin, Ethiopia

Soil loss is one of the most important concerns that experts are looking into for successful watershed management. The goal of this research is to use a modeling approach to estimate the spatial sediment yield and identify hotspot locations at the sub-watershed level within the Finca'aa watershed in the Abay River Basin, Ethiopia, from 1999 to 2017. The constructed rating curve from measured discharge-sediment loading was used to generate sediment data for the calibration and validation process. Model sensitivity analysis, calibration, and validation were performed using the Sequential Uncertainty Fitting version-2 (SUFI-2) technique. The calibration and validation are based on adjusted sediment sensitive parameters from 2001 to 2009 and 2010 to 2017, respectively. The coefficient of determination (R-2) and Nash-Sutcliffe (E-NS) through calibration and validation period were 0.84 and 0.79 and 0.79 and 0.74, respectively. The model has strong capacity to predict annual average sediment yield and identify vulnerable locations at the sub-watershed level from the Finca'aa watershed, according to the model performance criteria. As a result, yearly average soil loss for the entire watershed is 41.2t/ha/year and sub-watersheds (1, 8, 11, 14, 17, and 20) are among the 21 sub-watersheds with very significant soil erosion, contributing roughly 28 percent of the watershed's sediment yield. Primarily, greater attention for conservation should be given for these sub-watersheds. The outcome is very important for planners and resource managers in terms of immediate and long-term planning through integrated water resource management (IWRM).