The Ab’aro is a river of the

Nile The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river sy ...

basin. Rising in the mountains of Dogu’a Tembien in northern

Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...

, it flows northwestward to empty into the Weri’i, which is a tributary of

Tekezé River The Tekezé River (; , originally meaning "river" in Ge’ez; , also spelled Takkaze; ), is a major river in Ethiopia. For part of its course it forms a section of the westernmost border of Ethiopia and Eritrea. The river is also known as the Seti ...

Characteristics

The Ab’aro is a confined ephemeral river in its upper part, whereas it widely

meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...

s in the lower plains, with an average slope gradient of 60 metres per kilometre. Towards the footslope the river has cut a deep gorge (a cluse). Abaro Gorge

Flash floods

Runoff mostly occurs 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. In contrast to neighbouring rivers such as May Meqa, May Shoate or Giraliwdo, the magnitude of floods in Ab’aro has not been decreased due to interventions in the catchment. Physical conservation structures such as stone bunds and check dams that intercept runoff are absent. On the steep slopes, exclosures have not been established and there is no dense vegetation that could contribute to enhanced infiltration, less flooding or better

baseflow Baseflow (also called drought flow, groundwater recession flow, low flow, low-water flow, low-water discharge and sustained or fair-weather runoff) is the portion of the streamflow that is sustained between precipitation events, fed to streams by d ...

. As such, it is one of the few catchments that could stand model for conditions before major human interventions for conservation started in the

Tigray region The Tigray Region (or simply Tigray; officially the Tigray National Regional State) is the northernmost Regions of Ethiopia, regional state in Ethiopia. The Tigray Region is the homeland of the Tigrayan, Irob people, Irob and Kunama people. I ...

Lithology

From upstream to downstream, the following lithological units occur in the catchment. Abaro church

Phonolite Phonolite is an uncommon shallow intrusive or extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a var ...

plugs * Upper basalt * Interbedded lacustrine deposits * Lower basalt * Amba Aradam Formation * Antalo Limestone *

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

freshwater

tufa Tufa is a variety of limestone formed when carbonate minerals precipitation (chemistry), precipitate out of water in ambient temperature, unheated rivers or lakes. hot spring, Geothermally heated hot springs sometimes produce similar (but less ...

* Adigrat Sandstone 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 two woredas and constitutes their border for 2 kilometres. On the various parts: * Dogu’a Tembien to the southeast * Kola Tembien to the northwest

Transhumance towards Ab'aro

The valley bottoms in along middle Ab'aro have been identified as a transhumance destination zone.

Transhumance Transhumance is a type of pastoralism or Nomad, nomadism, a seasonal movement of livestock between fixed summer and winter pastures. In montane regions (''vertical transhumance''), it implies movement between higher pastures in summer and low ...

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

Trekking along the river

A trekking routes winds across and along this river. The tracks are not marked on the ground but can be followed using downloaded .GPX files. Trek Gh2 roughly follows the river, partly occupying the track of an old road dating back to the time of the Italian occupation. In the rainy season, flash floods may occur and it is advised not to follow the river bed.

References

{{reflist Rivers of Ethiopia Dogu'a Tembien Tigray Region Nile basin