Nile River Basin Freshwater in Average Year

Runoff is the Nile basin is strongly influenced by rainfall carried by the ITCZ (Inter Tropical Convergence Zone). The ITCZ is a key component of global circulation and is the area where northeast and south east trade winds converge solar heating causes moisture laden air to rise which leads to large amounts of rainfall. The location of this zone fluctuates through the year and this is reflected in the runoff maps, where during July August the Ethiopian highlands show high run off. During Dec to April the southernmost tip of the basin or White Nile has higher runoff than the Blue Nile originating in the Ethiopian highlands.