May Harena
| May Harena | |
|---|---|
 The May Harena River atHarena | |
  May Harena inDogu’a Tembien | |
| Etymology | After the homonymous village |
| Location | |
| Country | Ethiopia |
| Region | Tigray Region |
| District (woreda) | Dogu’a Tembien |
| Physical characteristics | |
| Source | |
| • location | Valley head east ofHagere Selam |
| • elevation | 2,480 m (8,140 ft) |
| Mouth | May ZegzegRiver |
• location | May Addi Abagiè at the border ofMika'el AbiyandHaddinnetmunicipalities |
• coordinates | 13°38′38″N39°11′38″E/ 13.644°N 39.194°E |
• elevation | 2,270 m (7,450 ft) |
| Length | 2.1 km (1.3 mi) |
| Width | |
| • average | 10 m (33 ft) |
| Basin features | |
| River system | Seasonal river |
| Landmarks | Hagere Selamtown |
| Topography | Mountains and deep gorges |
TheMay Harenais a river of theNilebasin. Rising in the mountains ofDogu’a Tembienin northernEthiopia,it flows eastward to empty finally in theGibaandTekezé River.[1]
Characteristics
[edit]The May Harena is a confined ephemeral river with an average slope gradient of 100 metres per kilometre.[2]
Hydrology
[edit]
River discharge in May Harena is highly seasonal, with the river only carrying water in the rainy season, after rain events. The problem is exacerbated by the fact that most of theurban drainagefromHagere Selamis rapidly directed to this river. Conservation activities (such as those by theSelam WatSaniproject aim at buffering these floods. There is however a strong contrast with better regularised adjacentMay Sho'ateRiver.
Flash floods and flood buffering
[edit]Runoff mostly happens in the form of high runoff discharge events that occur in a very short period (calledflash 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 precedingbaseflow.[2] The magnitude of floods in this river has somewhat been decreased due to interventions in the catchment. On some steep slopes,exclosureshave been established; the dense vegetation largely contributes to enhancedinfiltration,less flooding and betterbaseflow.[3]Physical conservation structures such asstone bunds[4][5]andcheck damsalso intercept runoff.[6][7]
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 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.[8]
Trekking along the river
[edit]Trekking routes have been established across and along this river.[9]The tracks are not marked on the ground but can be followed using downloaded.GPX files.[10]Trek12 Vruns parallel to the river, on its northern side.
See also
[edit]References
[edit]- ^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.ISBN978-3-030-04954-6.
- ^abAmanuel 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.ISBN978-3-030-04954-6.
- ^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; 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.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.doi:10.1016/j.jhydrol.2016.12.019.hdl:1854/LU-8518957.
- ^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.ISBN978-3-030-04954-6.
- ^Description of trekking routes in Dogu'a Tembien. In: Geo-trekking in Ethiopia's Tropical Mountains - The Dogu'a Tembien District.SpringerNature. 2019.ISBN978-3-030-04954-6.
- ^Public GPS traces tagged with nyssen-jacob-frankl | OpenStreetMap