Lake Tana (also spelled
T'ana, , , ; an older variant is
Tsana,
Ge'ez ጻና
Ṣānā; sometimes called "
Dembiya" after the region to the north of the lake) is the source of the
Blue Nile and is the largest lake in
Ethiopia. Located in
Amhara Region 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 1,788 meters. Lake Tana is fed by the
Lesser Abay,
Reb and
Gumara rivers; and its surface area ranges from 3,000 to 3,500 km,² depending on season and rainfall. The lake level has been regulated since the construction of the control
weir where the lake discharges into the Blue Nile. This controls the flow to the
Blue Nile Falls (Tis Abbai) and hydro-power station.