The Qortem Zer’a is a river of the Nile basin. Rising in the mountains of Dogu’a Tembien in northern Ethiopia, it flows westward to empty finally in the Weri’i and Tekezé River.[1]
| Qortem Zer’a | |
|---|---|
 The Qortem Zer’a River | |
  Qortem Zer’a River in Dogu’a Tembien | |
| Location | |
| Country | Ethiopia |
| Region | Tigray Region |
| Districts (woreda) | Dogu’a Tembien and Kola Tembien |
| Physical characteristics | |
| Source | May Baha |
| • location | Degol Woyane municipality |
| • elevation | 2,230 m (7,320 ft) |
| Mouth | Weri’i River |
• location | Kola Tembien |
• coordinates | 13°42′08″N 38°38′38″E / 13.70222°N 38.6438°E |
| Length | 15.4 km (9.6 mi) |
| Width | |
| • average | 15 m (49 ft) |
| Basin features | |
| Progression | Wari→Tekezé→Atbarah→Nile→Mediterranean Sea |
| River system | Seasonal river |
| Landmarks | Amanuel rock church in May Baha, Imba K’ernale Mt. |
| Bridges | Getski Melesiley on Abiy Addi-Werqamba road |
| Topography | Sharp mountains and plains |
Characteristics
editIt is an ephemeral river, mostly meandering in its alluvial plain, with an average slope gradient of 34 metres per kilometre.[2]
Flash floods and flood buffering
editRunoff 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]
Irrigated agriculture
editBesides springs and reservoirs, irrigation is strongly dependent on the river's baseflow. Such irrigated agriculture is important in meeting the demands for food security and poverty reduction.[2] Irrigated lands are established in the alluvial plain along the river, particularly west of Getski Melesiley.[1]
Transhumance towards the gorge
editTranshumance takes place in the summer rainy season, when the lands near the villages in the uplands and the lowlands are occupied by crops. Young shepherds will take the village cattle to the slopes at the river headwaters.[8]
Boulders and pebbles in the river bed
edit
Boulders and pebbles encountered in the river bed can originate from any location higher up in the basin. 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.[9]
From upper to lower Tembien
editDuring its course, this river passes through two woredas.[1] On the various parts:
- The headwaters are in Dogu’a Tembien
- Most of the lower plain is in Kola Tembien
Trekking along the river
editTrekking routes have been established across and along this river.[10] The tracks are not marked on the ground but can be followed using downloaded .GPX files.[11]
- Trek 5, along upper part of the river
- Trek S3, along the lower part, potentially down to Tekezé River
In the rainy season, flash floods may occur and it is advised not to follow the river bed. In the lower part, it may be impossible to cross the river in the rainy season.[12]
Gallery
edit-
Qortem Zer’a near Imba K’ernale mountain -
View over Qortem Zer’a towards May Baha
See also
editReferences
edit- ^ a b c 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.
- ^ a b c 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Description of trekking routes in Dogu'a Tembien. In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District. GeoGuide. SpringerNature. 2019. doi:10.1007/978-3-030-04955-3. ISBN 978-3-030-04954-6. S2CID 199294303.
- ^ "Public GPS Traces tagged with nyssen-jacob-frankl".
- ^ 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.