Modeling runoff-sediment response to land use/land cover changes using integrated GIS and SWAT model in the Beressa watershed

Land use/land cover (LU/LC) change has significant influence on runoff and sediment characteristics of any catchment. LU/LC change studies are essential for policy planners to understand the problems and take course of action such as soil and water conservation measures for improvement. The present study is conducted for Beressa watershed using hydrological model integrated with GIS. Input data like LU/LC, weather and soil data features are required to undertake watershed simulation. The model has been calibrated and validated in SWAT-CUP. The data from 1980 to 1999 were used for calibration, while the data from 2000 to 2014 were used for validation. LU/LC analysis showed that agricultural and settlement areas have increased between 1984 and 2015, while barren, grazing land and forest area have decreased. However, the share of forest cover increased in between 1999 and 2015. SWAT model has successfully simulated and calibrated runoff and sediment yield. During calibration periods (1980-1999), the values of R-2, NSE, RSR and PBIAS were obtained as 0.72, 0.67, 0.52 and 3.9%, respectively, whereas during the validation periods (2000-2014) the values were 0.68, 0.64, 0.56 and 7.6%, respectively. Runoff and sediment yield has significantly increased. Thus, it is concluded that the change in LU/LC significantly influenced the runoff and sediment yield.