Hydrological modeling of Oued El Abiod watershed using the SWAT model

The sub-Saharan climate dominates the region of Biskra which is recognized by its palm grove. The objective of this work is the application and testing of spatial modeling as a management tool for simulating the functioning of water resources at the Oued El Abiod watershed. The Soil Water Assessment Tool (SWAT) has been used to measure the flow to the watershed Oued El Abiod which is the important source of water irrigation at Biskra. The SWAT CUP has been applied for calibration and analyzing parameter uncertainty of the SWAT model. The performance of the SUFI-2 techniques was evaluated using two objective functions, the coefficient of determination R2 and Nash–Sutcliffe (NS). The results show that the correlation during the monthly calibration and validation times between observed and simulated flows is good, therefore. NS (Q) of 0.56 in calibration against 0.53 in validation and R2 of 0.72 in calibration against 0.78 in validation. Also among the components of the water balance, evaporation and evapotranspiration are predominant. Sixty-eight percent of the annual precipitation is evaporated. The surface runoff is approximately 40 mm. As for the total flow in the river, it is around 125 mm. This can be explained mainly by feeding on the lateral flows (33.8 mm) and the aquifer, taking into account the presence of an impermeable substrate in the Oued El Abiod watershed. Indeed, the percolation value is 85.82 mm or a percentage of around 19% and the recharge of the deep water table is 4.29 mm or a percentage of 1%. Due to insufficient water quantity in Biskra, the knowledge of different terms of the water cycle in Oued El Abiod watershed is very important for the management of water resources in Biskra.