SPATIAL DISTRIBUTION OF SEDIMENT YIELD AND WATERSHED MANAGEMENT PRACTICES IN KULFO WATERSHED (RIFT VALLEY BASIN, ETHIOPIA)
Sediment is a major problem threatening the life of many of our lakes and reservoirs. It also affects the economy of many developing countries, hence Ethiopia. The main purpose of this study is to assess the effectiveness of watershed management interventions on the severely eroded regions of Kulfo watershed in Ethiopia. Hydro-meteorological and spatial data of Kulfo watershed were used to identify the hot spot regions. The observed stream flow data series of Kulfo near bridge and four meteorological station data were used. All the data length covers the period from 2000-2019. The main geomorphic parameters of the watershed were developed by using a 30m x 30m Digital Elevation Model. The spatial distribution of sediment yield of the catchment was performed by using the Soil and Water Assessment Tool. Scenarios were developed to assess the effectiveness of watershed management practices at the watershed and critical sub-watershed level. The performance of the model was evaluated by NSE and resulted in 0.79 and 0.70 during calibration and validation respectively. Twenty-one sub-basins were created and the observed average sediment yield was 11.9ton/ha/yr. The observed average annual sediment yield reduction at the hotspot sub-basins level after application of contouring, filter strip, terracing and strip cropping was 40.79%, 57.94%, 66.02% and 62.93% respectively. In general, we can conclude that terracing is the best conservation measure on majority of the affected sub-basins.