Understanding the hydrological functioning of watersheds in sub-humid tropical regions is a key challenge for the sustainable management of water resources, particularly in contexts subject to significant human and climate pressures. This study assesses the hydrological water balance of the Douni watershed, located in northwestern C？te d’Ivoire, using the semi-distributed SWAT model. This modeling is based on hydroclimatic and discharge data covering the periods 1980-2020 and 1980-1996, respectively, as well as cartographic data (topographic, pedological, and land-use). Model calibration and validation were performed, respectively, on the periods from 1982 to 1987 and from 1988 to 1992 using the SUFI-2 algorithm. The performance obtained is considered satisfactory, with NSE values of 0.51 after calibration and 0.50 in validation, coefficients of determination (R2) close to 0.52 and limited biases (PBIAS between ？6.4% and +5.4%), as well as high P-factor (0.72) and low R-factor (0.53) values, reflecting a good reproduction of the seasonal dynamics of flows. The water balance shows that actual evapotranspiration dominates (62%), followed by surface runoff (28%), while infiltration (10%) and deep groundwater recharge (<1%) remain low. These results reflect the basin’s high hydrological responsiveness, characterized by a predominance of surface and subsurface runoff and a low contribution to deep aquifer recharge. This provides clear guidance on how to mobilize water resources to meet various water needs. In this context, the choice of mobilizing surface water appears as a relevant option in the management of the Douni basin. In light of these results, the SWAT model could serve as a decision-making tool for the integrated and sustainable management of water resources in the Douni Basin (northwest C？te d’Ivoire).
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