<P> The Niger River is a relatively "clear" river, carrying only a tenth as much sediment as the Nile because the Niger's headwaters lie in ancient rocks that provide little silt . Like the Nile, the Niger floods yearly; this begins in September, peaks in November, and finishes by May . </P> <P> An unusual feature of the river is the Inner Niger Delta, which forms where its gradient suddenly decreases . The result is a region of braided streams, marshes, and lakes the size of Belgium; the seasonal floods make the Delta extremely productive for both fishing and agriculture . </P> <P> The river loses nearly two - thirds of its potential flow in the Inner Delta between Ségou and Timbuktu to seepage and evaporation . All the water from the Bani River, which flows into the Delta at Mopti, does not compensate for the' losses' . The average' loss' is estimated at 31 km / year, but varies considerably between years . The river is then joined by various tributaries, but also loses more water to evaporation . The quantity of water entering Nigeria measured in Yola was estimated at 25 km / year before the 1980s and at 13.5 km / year during the 1980s . The most important tributary of the Niger in Nigeria is the Benue River which merges with the river at Lokoja in Nigeria . The total volume of tributaries in Nigeria is six times higher than the inflow into Nigeria, with a flow near the mouth of the river standing at 177.0 km / year before the 1980s and 147.3 km / year during the 1980s . </P> <P> The Niger takes one of the most unusual routes of any major river, a boomerang shape that baffled geographers for two centuries . Its source is just 240 km (150 mi) inland from the Atlantic Ocean, but the river runs directly away from the sea into the Sahara Desert, then takes a sharp right turn near the ancient city of Timbuktu (Tombouctou) and heads southeast to the Gulf of Guinea . </P>

Where did river niger and river benue meet