Stormwater is also a resource and important as the world's human population demand exceeds the availability of readily available water. Techniques of storm water harvesting with point source water management and purification can potentially make urban environments self-sustaining in terms of water.
Rivers flow downhill to sea level (generally speaking; some end in other bodies of water or join another rver). They flow with gravity from a higher elevation to a lower. The Nile rises on the western flank of the Great Rift Valley (many people consider Lake Victoria to be the source) and the Blue Nile joins the White Nile at Khartoum. The land falls away towards the north, thus the river flows north until it reaches the Mediterranean Sea at the Nile Delta. Direction of flow of a river is determined by elevation of the drainage basin, not geographical (North, South etc.) direction. http://en.wikipedia.org/wiki/Nile#Course.
Quick Answer. Africa's Nile River flows northward, emptying into the Mediterranean Sea. The Nile's two main tributaries are the Blue and White Nile Rivers, which originate in Ethiopia and Eretria's highlands and the Equatorial Lakes Region, respectively. Continue Reading.