Cartographie et prédiction des risques d'érosion hydrique dans le bassin versant de la Yewa (Benin).

Water erosion is the most common type of soil degradation in the Yéwa watershed and has been recognized as a major problem. The objective is to study the vulnerability of soils to erosion in the Yéwa watershed using the SIMWE model. Using a GIS, allowing to spatialize and cross a digital terrain model, a directional flow gradient, excess precipitation rate, the roughness coefficient, the runoff depth, the soil erodibility, the coefficient transport capacity and critical shear stress, this study made it possible to predict the sensitivity to water erosion. The prediction result shows that 55.23% (480.64 km2) of the watershed has a low to moderate sensitivity to erosion for 3.84% (33.45 km2) severe to very severe sensitivity. As for the deposit, 18.58% (161.71 km2) of the basin area reveals a low to moderate deposit for 3.90% (33.98 km2) of high to very high deposit with a positive balance of around 4120.44 t / ha / year. Lesser soil losses are associated with dense cover such as dense forests in the southern part of the basin and, conversely, higher values are associated with bare soil or degraded undercover. This study could constitute the starting point for the implementation of a coordinated management of erosion control actions and contribute to the understanding of current dynamics. [ABSTRACT FROM AUTHOR]