Volume 11 Article informations Contribution of GIS for water erosion risk assessment in the Sahbi River watershed (North-West of Tunisia) Arbi Chafai, Nadhem Brahim, Najet Slim Shimi Abstract Tunisia, a southern Mediterranean country, is characterized by the vulnerability of its resources, mainly water and soil, which are subject to various forms of degradation, the most common of which is water and wind erosion. Indeed, water erosion is intensifying in several regions of the world and especially in North Africa, affecting nearly 3 million hectares of agricultural land in Tunisia. It causes disastrous damage upstream and downstream of hydraulic infrastructures while affecting the sustainability of the latter. Water erosion is caused by a combination of several physico-climatic factors, namely rainfall, relief, cultivation practices, land use and soil characteristics. In the present study, we will adopt the RUSLE (Revised Universal Soil Loss Equation) model to evaluate the quantities of soil losses at the scale of the Sahbi River watershed (north-west Tunisia). The application of the RUSLE approach combines the main erosion factors in a geographic information system. The resulting soil loss map shows a low erosion (< 4 t/ha/year) covering 87.94% of the total surface area of the basin, and a very high erosion (> 33t/ha/year) not exceeding 1% of the surface area. The areas with high erosion rates are mainly recorded at the level of areas characterized by a steep slope, high erodability and low vegetation cover, which shows the importance of this phenomenon at the level of the studied basin.