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.

The sensitivity of subtropical African river basins to possible future climate change is a matter of some concern. In Ivory Coast, previous works on climate change impacts predict a decrease in annual average water resource by the 2080s between 6.9% and 8.4%. This is a potentially serious issue because of a series of historical resource management decisions that have increased dependence upon water use, such as through major dam building schemes. This paper focuses upon the Buyo Lake catchment, a central resource for the Ivorian people with the aim of providing future water resource scenarios, under climate change so as to develop appropriate adaptation policies. The study applied simulations from the UKMO climate model, HadGEM1 from the ENSEMBLES project 2009, with the A1B emissions scenario in continuous simulation. Daily climate data such as rainfall, temperature, wind speed and relative humidity were input to the SWAT hydrological model. The simulations were performed after model calibration. Analysis focuses on the periods 1950-1979 (baseline), 2035-2064 (2050 horizon) and 2064-2093 (2080 horizon).The results showed that the entire basin of Buyo could experience a serious temperature elevation of +1.34