CONTRIBUTION OF WATER EROSION TO COASTAL SEDIMENTARY MORPHODYNAMICS: QUANTIFICATION USING UNIVERSAL SOIL LOSS (RUSLE) IN THE KAFOUNTINE WATERSHED (SOUTHERN SENEGAL)

Lower Casamance is characterized by a set of watersheds drained by permanent streams that flow directly to their mouths. Among these watersheds, we have Kafountine, which, like all others, participates in the sedimentary morphodynamics of the coastline through the water erosion that occurs especially upstream, on the slopes. The sediments transported and deposited are usually composed of fine sands forming accumulations in places that stabilize the beaches. The objective of this study is to estimate the amount of sediment eroded in the Kafountine watershed and transported to the coast. To do this, we used the Wischmeier and Smith Universal Soil Loss Equation (RUSLE) (1978), which is frequently used to calculate the average annual soil loss per unit of land resulting from slick and channel erosion. The equation is applied after the data is integrated into a Geographic Information System (GIS). The results from the overlapping of factors tell us that the Kafountine watershed is losing on average 54.5 t/ha/an.