The Gilgel Abay (Amharic: ግልገል አባይ, Gǝlgäl Abbay), or Lesser Abay, is a river of central Ethiopia. Rising in the mountains of Gojjam, it flows northward to empty into south-western Lake Tana in a bird's-foot delta. Tributaries of the Gilgel Abbay include the Ashar, Jamma, Kelti and the Koger. It was regarded as the true source of the Nile for a long time and the Jesuit priest Pedro Paez visited it in 1618. The name Gilgel Abbay means Lesser Nile, as Abbay is the name for the Blue Nile.

Characteristics

It is a meandering river, with a catchment area of 3,887 km2 (1,501 sq mi). It is 71 meters wide near its mouth, with a slope gradient of 0.7 m/km. The average diameter of the bed material is 0.37 mm (sand).

Sediment transport

The river carries annually 22,185 tonnes of bedload and 7.6 million tonnes of suspended sediment to Lake Tana.

See also

Further reading

  • S. Uhlenbrook, Y. Mohamed, and A. S. Gragne, "Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia." Hydrol. Earth Syst. Sci., 14, 2153–2165, 2010
  • Hydrologic Impact of Land-Use Change in The Upper Gilgel Abay River Basin, Ethiopia; TOPMODEL