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.
| Gilgel Abay Lesser Abay | |
|---|---|
 Gilgel Abay at BIkolo, during flood | |
 Map of Lake Tana, showing rivers flowing into it | |
| Etymology | Literally "Lesser Nile" |
| Native name | ግልገል አባይ (Amharic) |
| Location | |
| Country | Ethiopia |
| Region | Amhara |
| Zone | West Gojjam |
| Physical characteristics | |
| Source | |
| • location | Near Gish Abay |
| • coordinates | 11°00′41″N 37°09′08″E / 11.01147°N 37.15229°E |
| • elevation | 2,454 m (8,051 ft) |
| Mouth | Lake Tana |
• location | 12.5 km (7.8 mi) SE of Kunzila |
• coordinates | 11°47′55″N 37°07′31″E / 11.798679°N 37.125324°E |
• elevation | 1,786 m (5,860 ft) |
| Length | 154.5 km (96.0 mi) |
| Basin size | 3,887 km2 (1,501 sq mi) |
| Width | |
| • maximum | 71 m (233 ft) |
| Basin features | |
| Progression | Lake Tana → Blue Nile → Nile → Mediterranean Sea |
| River system | Nile Basin |
| Population | 1,220,000 |
Characteristics
editIt 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).[1]
Sediment transport
editThe river carries annually 22,185 tonnes of bedload and 7.6 million tonnes of suspended sediment to Lake Tana.[1]
See also
editReferences
edit- ^ a b Hanibal Lemma, and colleagues (2019). "Bedload transport measurements in the Gilgel Abay River, Lake Tana Basin, Ethiopia". Journal of Hydrology. 577: 123968. doi:10.1016/j.jhydrol.2019.123968.
Further reading
edit- 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 http://www.itc.nl/library/papers_2010/msc/wrem/gumindoga.pdf