An Evaluation of the Sediment Storage in the Niger Inland Floodplain in Mali

Between the cities of Segou and Dire in Mali, the Niger River enters into a large alluvial plain (60,000 km2): the Niger Inland Delta. The presence of this floodplain has an important impact in the sediment budget of the River. Using the methods of sediment balance analysis (sediment input and output), this study shows that 16.9-50% of the sediments provided by the upper Niger Basin (76.5%) and the Bani River Basin (23.5%) is stored. The sediment flux and storage vary with the water discharge. The two main parts of the inland delta: the southern delta or the lakes area and the northern delta called the erg region behave differently. The southern delta is a sediment sink (26-53% of sediment deposited); the erg region is an area of erosion. The main consequence of this sediment storage is the aggradation and the geomorphological change of the floodplain.