Assessment of soil erosion risk in a semi-arid climate watershed using SWAT model: case of Tata basin, South-East of Morocco

Abstract Increased sedimentation is the main problem that affects dam efficiency by reducing storage capacity. Planning for construction and maintenance requires design strategies heavily depend on integrated basin models, properly identifying principal sediment origins within watershed qualifying production rate. In this research work, physically-based SWAT model, defined as Soil Water Assessment Tool, was used to estimate rate of future dams in Tata basin, located southeast Morocco. The model calibrated tested uncertainty employment algorithm Sequential Uncertainty Fitting-2. outputs were assessing critical source areas. Calibration validation performed monthly data. values Nash–Sutcliffe coefficient, Percent bias coefficient determination (R 2 ), respectively, during calibration period 1990–1998 (0.96, ?13% 0.96) 1999–2006 (0.77, + 11% 0.93) indicate accordance with results obtained measured flow simulated values. annual yield extends from 0 11 t/ha/y a mean 2.3 t/ha/y. spatial distribution these sediments varies upstream downstream. downstream generated more river per unit area, though it less than total amount area. This variation influenced increased surface runoff also other characteristics such slope lithology. low erosion places correspond areas lithological formations are resistant erosion.