Caractérisation et quantification des flux sédimentaires éoliens participant au comblement des lacs du Sahel central : cas de Bangou Bi (SW Niger)

In Niamey region, ponds and lakes formed in the past six decades are being filled with a sedimentation rate of 4 cm per year. The cultivated sandy soils covering their watershed are prone to wind and water erosions. This work aimed to estimate the proportion of aeolian deposits in the filling of one of these lakes, Bangou Bi, by the means of aeolian deposition flux measurements on the lake and wind erosion flux measurements on cultivated and bare soils. It appeared that more than 70% of aeolian deposits on Bangou Bi were provided by locale wind erosion that is controlled by the annual cycle of cultivated and bare soils erosion. Anyway, these deposits only reached a maximum thickness of 400μm per year which appears negligible in the filling of the lake.