Source of the Blue Nile: Lake Tana, Ethiopia
Lake Tana, which appears white due to sun glint, is the source of the Blue Nile and is the largest lake in Ethiopia.
Located in the north-western Ethiopian highlands, the lake is approximately 84 kilometers long and 66 kilometers wide, with a maximum depth of 15 meters, and an elevation of 1,840 meters.
Lake Tana is fed by the Little Abbai, Reb and Gumara Rivers and its surface area ranges from 3,000 to 3,500 km² depending on season and rainfall.
The lake level has been regulated since the construction of the control weir (lowhead dam) where the lake discharges into the Blue Nile. This weir regulates the flow to the Tis Abbai falls and hydro-power station.
The lake has a number of islands, whose numbers vary depending on the level of the lake; it has fallen about 6 feet in the last 400 years. The large island visible in the image is called Dek Island.