Euro-Mediterranean Journal for Environmental Integration
Abstract:
The management of surface water in basins has become of the utmost importance, especially given the expected changes in climate and land use. Therefore, the current work aimed to aid the management of the Khazir River basin by estimating sediment yield and surface runoff using the Soil and Water Assessment Tool (SWAT) at the hydrological response unit (HRU) spatial level. The SWAT model was used to simulate hydrological processes and sediment transport at different spatial and temporal scales in the basins. The study of sub-basins allowed more precise targeting of the best management practices through analysis and evaluation. The accuracy of, uncertainty in, and sensitivity of the parameters were evaluated by comparing observed and simulated daily data for average surface runoff and sediment yield. The semi-automated sequential uncertainty fitting (SUFI-2) algorithm within the SWAT CUP model was employed to calibrate the model parameters using the time series for the period 2003–2008, and its validity was verified for the period 2009–2012. The surface runoff performance was good during calibration (Nash–Sutcliffe efficiency (NSE) = 0.77) and very good during verification (NSE = 0.82), while it was good for sediment yield during the calibration and validation periods (NSE = 0.71 and NSE = 0.75, respectively). The parameters related to the characteristics of sediment yield and surface runoff showed high sensitivity during calibration and validation, as they are affected by the length and degree of slope, vegetation cover, and the resulting soil exposure to water erosion. The obtained results were compared with the results of previous scientific studies conducted for North African basins, and this comparison indicated the need for continuous study of the spatial and temporal changes in the natural characteristics of the basins. The results could help basin managers to determine baseline rates of hydrological processes in light of expected future shifts in hydrological systems as a result of climate and land-use changes.
