ETUDE DE LEROSION HYDRIQUE AVEC UNE APPROCHE DE MESURE PAR PARCELLES EXPERIMENTALES: CAS DU BASSIN DE LA YEWA (BENIN)

The Yewa River basin has a predominantly rural economy. With agricultural expansion and cultivation practices, coupled with loss of vegetation cover, climatic aggressiveness and slope, the basin is sensitive to the process of sediment removal and accumulation. The present study aims to analyse the vulnerability of soils to water erosion by using a plot-based approach to measure the vulnerability of experimental parcels to degradation factors. Two transects, notably at the sub-basin of Aguidiat Lagbe and Akoligbe at Vagnon, underwent experimentation and provided results from the sediment stakes and traps in terms of ablation and addition of materials within the basin. The results show that the quantity of sediment varies according to topographic facets, the plant formation in place, the nature of the soil and the slope system. The sediment balance is of the order of 3244.31 t/ha/year with an erosion rate of 180.18 cm/year upstream and 2785.82 t/ha/year with an erosion rate of 109.02 cm/year downstream. The soils are sandy-clay and sandy-silty upstream clay-sandy and sandy-silty downstream. In response to this degradation, the populations of the watershed have developed modern strategies and remedial measures to mitigate the effects for soil conservation