Soil erosion by water is soil loss due to water pulling and transporting the soil to a deposition site. This is the major cause of soil degradation and siltation of hydro systems. Knowledge of this phenomenon is therefore essential for better management of dam water resources. The site of the study is the watershed of the hydro-agricultural dam of Babadou. It is a small agricultural catchment area of 1630 ha in the center-west of Côte d'Ivoire. The objective of this work is to highlight the erosion by water risks and sediment transport. Thus, the Universal Soil Loss Equation (USLE) was not only used to model the factors involved in the erosion process, but also for the calculation of soil losses through a Geographic Information System (GIS). The results show an average soil loss of 6.9 t/ha/year, which represents a soil loss of 11247 t/year in the Babadou dam watershed. In addition, the soil loss map, carried out, highlights the area’s most sensitive to erosion with soil losses reaching 767.4 t/ha/year. They are generally at the regions of bare soils and areas of annual crops. The sustainability of the water resource of the hydro-agricultural dam at Babadou requires the correction of vegetation cover and the use of anti-erosion practices in these areas, with a view to reducing soil loss and sediment flow.