Assessment of water balance based on SWAT hydrological model: a case study of Oued Cherraa basin (Northeastern Morocco).

The aim of the present study is to assess the hydrological water balance of Oued Cherraa catchment area in north-eastern Morocco, employing the SWAT (soil and water assessment tool) hydrological model. The principal goal was to examine pivotal elements of the water balance (precipitation, evapotranspiration, runoff, and aquifer recharge) and their geographical variation to offer insights for the sustainable management of water resources in this semi-arid region. The model was calibrated and validated using local climate and hydrological data. The resulting values indicated a moderate underestimation of observed flow, with the calibration having a PBIAS value of - 9.1 and the validation a PBIAS of - 0.2. A sensitivity analysis identified the deep aquifer percolation fraction (RCHRG_DP) and the baseflow recession coefficient (ALPHA_BF) as the most influential parameters. The study demonstrates that evapotranspiration represents 89% of annual precipitation, while runoff contributes only 6%. The role of shallow aquifers in water storage is more significant than that of deep aquifers, and irrigation practices have a notable impact on groundwater levels. These findings emphasize the necessity for sustainable water management and meticulous monitoring of aquifers to prevent overexploitation in Oued Cherraa basin. The SWAT model is demonstrated to be a valuable instrument for water resource management in semi-arid regions.