Agefet

Agefet is a river of the Nile basin. Rising in the mountains of Gheralta in northern Ethiopia, it flows westward to empty finally in Weri’i and Tekezé River.

The river in the radial drainage network of Dogu’a Tembien

Agefet
The Agefet River at Hazgi
Agefet River in Dogu’a Tembien
Location
Country	Ethiopia
Region	Tigray Region
District (woreda)	Dogu’a Tembien
Physical characteristics
Source	Gheralta
• location	8 km east of Tsigereda
• elevation	2,135 m (7,005 ft)
Mouth	Tsaliet River
• location	between Addeha and Gelebeda
• coordinates	13.8020°N 39.1156°E / 13.8020; 39.1156
• elevation	1,604 m (5,262 ft)
Length	41 km (25 mi)
Width
• average	55 m (180 ft)
Basin features
River system	Seasonal/permanent river
Landmarks	Kayeh Be’ati caves in Addi Nkrti
Tributaries
• left	Amblo, Azef River, Ab'aro[1]
Waterbodies	Ginda'i reservoir
Bridges	on the Werqamba-Hawzien road; on the Tsigereda-Wukro road
Topography	Mountains and deep gorges

Characteristics

Downstream course of Agefet

It is a confined ephemeral river, locally meandering in its narrow alluvial plain, with an average slope gradient of 13 metres per kilometre. At the end of its course, it occupies a sandy pediment.[2]

Flash floods and flood buffering

Runoff mostly happens in the form of high runoff discharge events that occur in a very short period (called flash floods). These are related to the steep topography, often little vegetation cover and intense convective rainfall. The peaks of such flash floods have often a 50 to 100 times larger discharge than the preceding baseflow.[2] The magnitude of floods in this river has however been decreased due to interventions in the catchment. Physical conservation structures such as stone bunds[3][4] and check dams intercept runoff.[5][6] On many steep slopes, exclosures have been established; the dense vegetation largely contributes to enhanced infiltration, less flooding and better baseflow.[7]

Transhumance towards the gorge

Transhumance takes place in the summer rainy season, when the lands near the villages are occupied by crops. Young shepherds will take the village cattle down to the Agefet gorge. The gorges are particularly attractive as a transhumance destination zone, because there is water and good growth of semi-natural vegetation.[8]

Boulders and pebbles in the river bed

From upstream to downstream, the following lithological units occur in the catchment.[9]

• Phonolite plugs
• Upper basalt
• Interbedded lacustrine deposits
• Lower basalt
• Amba Aradam Formation
• Antalo Limestone
• Quaternary freshwater tufa[10]
• Adigrat Sandstone
• Edaga Arbi Glacials

Logically, in the uppermost stretches of the river, only the pebbles and boulders of the upper lithological units will be present in the river bed, whereas more downstream one may find a more comprehensive mix of all lithologies crossed by the river.

Natural boundary

During its course, this river passes through three woredas (Kola Tembien, Dogu’a Tembien and Kilte Awula’ilo) and constitutes the border between the two latter over a dozen of kilometres.[11]

Trekking along the river

Trekking routes have been established across and along this river.[12] The tracks are not marked on the ground but can be followed using downloaded .GPX files.[13]

• Trek Gh1, follows the river in its eastern course
• Trek Gh2, crosses the river in its western course

In the rainy season, flash floods may occur and it is advised not to follow the river bed. Generally, it is impossible to cross the river in the rainy season.[14]

See also

• List of Ethiopian rivers

References

1. Jacob, M. and colleagues (2019). Geo-trekking map of Dogu'a Tembien (1:50,000). In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District. SpringerNature. ISBN 978-3-030-04954-6.
2. Amanuel Zenebe, and colleagues (2019). The Giba, Tanqwa and Tsaliet rivers in the headwaters of the Tekezze basin. In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District. SpringerNature. doi:10.1007/978-3-030-04955-3_14. ISBN 978-3-030-04954-6.
3. Nyssen, Jan; Poesen, Jean; Gebremichael, Desta; Vancampenhout, Karen; d'Aes, Margo; Yihdego, Gebremedhin; Govers, Gerard; Leirs, Herwig; Moeyersons, Jan; Naudts, Jozef; Haregeweyn, Nigussie; Haile, Mitiku; Deckers, Jozef (2007). "Interdisciplinary on-site evaluation of stone bunds to control soil erosion on cropland in Northern Ethiopia". Soil and Tillage Research. 94 (1): 151–163. doi:10.1016/j.still.2006.07.011. hdl:1854/LU-378900.
4. Gebeyehu Taye and colleagues (2015). "Evolution of the effectiveness of stone bunds and trenches in reducing runoff and soil loss in the semi-arid Ethiopian highlands". Zeitschrift für Geomorphologie. 59 (4): 477–493. doi:10.1127/zfg/2015/0166.
5. Nyssen, J.; Veyret-Picot, M.; Poesen, J.; Moeyersons, J.; Haile, Mitiku; Deckers, J.; Govers, G. (2004). "The effectiveness of loose rock check dams for gully control in Tigray, Northern Ethiopia". Soil Use and Management. 20: 55–64. doi:10.1111/j.1475-2743.2004.tb00337.x.
6. Etefa Guyassa and colleagues (2017). "Effects of check dams on runoff characteristics along gully reaches, the case of Northern Ethiopia". Journal of Hydrology. 545 (1): 299–309. doi:10.1016/j.jhydrol.2016.12.019.
7. Descheemaeker, K. and colleagues (2006). "Runoff on slopes with restoring vegetation: A case study from the Tigray highlands, Ethiopia". Journal of Hydrology. 331 (1–2): 219–241. doi:10.1016/j.still.2006.07.011.
8. Nyssen, Jan; Descheemaeker, Katrien; Zenebe, Amanuel; Poesen, Jean; Deckers, Jozef; Haile, Mitiku (2009). "Transhumance in the Tigray highlands (Ethiopia)". Mountain Research and Development. 29 (3): 255–264. doi:10.1659/mrd.00033.
9. Sembroni, A.; Molin, P.; Dramis, F. (2019). Regional geology of the Dogu'a Tembien massif. In: Geo-trekking in Ethiopia's Tropical Mountains — The Dogu'a Tembien District. SpringerNature. ISBN 978-3-030-04954-6.
10. Moeyersons, J. and colleagues (2006). "Age and backfill/overfill stratigraphy of two tufa dams, Tigray Highlands, Ethiopia: Evidence for Late Pleistocene and Holocene wet conditions". Palaeogeography, Palaeoclimatology, Palaeoecology. 230 (1–2): 162–178. Bibcode:2006PPP...230..165M. doi:10.1016/j.palaeo.2005.07.013.
11. Jacob, M. and colleagues (2019). Geo-trekking map of Dogu'a Tembien (1:50,000). In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District. SpringerNature. ISBN 978-3-030-04954-6.
12. Description of trekking routes in Dogu'a Tembien. In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District. SpringerNature. 2019. ISBN 978-3-030-04954-6.
13. https://www.openstreetmap.org/traces/tag/nyssen-jacob-frankl
14. Nyssen, Jan (2019). "Logistics for the Trekker in a Rural Mountain District of Northern Ethiopia". Geo-trekking in Ethiopia's Tropical Mountains. GeoGuide. Springer-Nature. pp. 537–556. doi:10.1007/978-3-030-04955-3_37. ISBN 978-3-030-04954-6.