SWAT streamflow modeling for hydrological components’ understanding within an agro-sylvo- pastoral watershed in Morocco

Being generally described as coherent entities in hydrological sense, watersheds are considered as study units to assess hydrological cycles and to come up with water management strategies. Hydrological modeling is a tool that can offer the chance to achieve these goals. The model Soil and Water Assessment Tool (SWAT) has been widely used in various parts of the world to support decision making on water management, and proved its efficiency in many arid and semi-arid areas even when different economical activities are held in the watershed (farming, pasture, forestry...). In this study, the SWAT model has been applied over R dom watershed, agro-sylvo- pastoral basin located in a semi-arid area in North-Western Morocco, with the aim to simulate the hydrological processes occurring in the study basin as a preliminary step. The simulation was performed across the period 2004 to 2009 and gave satisfactory goodness-of-fit levels in daily time step (NSE= 0.58, R^2= 0.79, PBIAS=19% during calibration and NSE=0.65, R^2= 0.73, PBIAS=20% during validation). The results of the study showed that the water balance in R dom watershed is dominated by evapotranspiration (61% of rainfall); surface runoff and water yield represent 8.3% and 25.2% of rainfall respectively. The water resources distribution within the watershed is uneven and follows a decreasing gradient matching the flow direction. The SWAT model succeeded to reflect the different hydrological processes in the study watershed and can be used to build integrated watershed management strategies within the studied basin and in other similar contexts.