Ferrey
The Ferrey valley
Ferrey River is located in Ethiopia
Ferrey River
Ferrey River in Dogu’a Tembien
Location
CountryEthiopia
RegionTigray Region
District (woreda)Dogu’a Tembien
Physical characteristics
SourceFerrey
 • locationDegol Woyane municipality
 • elevation2,203 m (7,228 ft)
MouthTsaliet River
 • location
Underneath Dabba Selama monastery
 • coordinates
13°41′46″N 39°06′14″E / 13.696°N 39.104°E / 13.696; 39.104
 • elevation
1,780 m (5,840 ft)
Length3 km (1.9 mi)
Width 
 • average7 m (23 ft)
Basin features
River systemPermanent river
LandmarksFerrey gardens, Dabba Selama monastery
WaterfallsNumerous rapids
TopographyMountains and deep gorges

The Ferrey is a river of the Nile basin. Rising in the mountains of Dogu’a Tembien in northern Ethiopia, it flows northward to empty finally in Weri’i and Tekezé River.[1]

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

Characteristics

It is a confined bedrock river, with an average slope gradient of 141 metres per kilometre.[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: exclosures have been established; the dense vegetation largely contributes to enhanced infiltration, less flooding and better baseflow.[3] Physical conservation structures such as stone bunds[4][5] and check dams also intercept runoff.[6][7]

Irrigated agriculture

In the valley head there are many springs that have allowed an age-old irrigation system to be established.[1] Such irrigated agriculture is important in meeting the demands for food security and poverty reduction.[2] The irrigated lands allow growing tropical fruits such as a local banana cultivar, lime and trunghi.[8]

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 lower parts of the valley and overnight in small caves. The lower valley is particularly attractive as a transhumance destination zone, because there is water and good growth of semi-natural vegetation.[9]

Boulders and pebbles in the river bed

Boulders and pebbles encountered in the river bed can originate from any location higher up in the catchment. In the uppermost stretches of the river, only rock fragments 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. From upstream to downstream, the following lithological units occur in the catchment.[10]

Trekking along the river

Trekking routes have been established across and along this river.[8] The tracks are not marked on the ground but can be followed using downloaded .GPX files.[11]

  • Trek 4, across the valley head with its tropical gardens

In the rainy season, flash floods may occur and it is advised not to follow the river bed.[12]

See also

References

  1. 1 2 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. 1 2 3 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. S2CID 199099067.
  3. ↑ 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. hdl:1854/LU-378900.
  4. ↑ 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.
  5. ↑ 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. Bibcode:2015ZGm....59..477T. doi:10.1127/zfg/2015/0166.
  6. ↑ 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.
  7. ↑ 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. Bibcode:2017JHyd..545..299G. doi:10.1016/j.jhydrol.2016.12.019. hdl:1854/LU-8518957.
  8. 1 2 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.
  9. ↑ 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. hdl:1854/LU-854326.
  10. ↑ 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.
  11. ↑ "Public GPS Traces tagged with nyssen-jacob-frankl".
  12. ↑ 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. S2CID 199198251.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.