The Azef River is a river in the Nile basin. Rising in the mountains of

Dogu’a Tembien Dogu'a Tembien (, "Upper Tembien", sometimes transliterated as Degua Tembien) is a woreda in Tigray Region, Ethiopia. It is named in part after the former province of Tembien. Nowadays, the mountainous district is part of the Southeastern Tigray ...

in northern Ethiopia, it flows northward to empty finally in Weri’i and Tekezé River. DT drainage

Characteristics

It is a confined ephemeral bedrock river, with an average slope gradient of 63 metres per kilometre. With its tributaries, the river has cut a deep gorge.

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. The magnitude of floods in this river has however been decreased due to interventions in the catchment. On steep slopes, exclosures have been established; the dense vegetation largely contributes to enhanced infiltration, less flooding and better baseflow. Physical conservation structures such as stone bunds and check dams also intercept runoff.

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 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.

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. * Upper basalt * Interbedded lacustrine deposits * Lower basalt *

Amba Aradam Formation The Amba Aradam Formation is a Cretaceous sandstone formation in Ethiopia. It is up to 200 metres thick, for instance in the Degua Tembien district. As fossils are absent, the age of the Amba Aradam Formation was interpreted based on the age of a ...

* 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). It follows the Neogene Period and spans from 2.58 million years ...

freshwater tufa * Adigrat Sandstone

Natural boundary

Over its whole course, this river constitutes the border between the municipalities of

Addi Walka Addi Walka is a ''tabia'' or municipality in the Dogu'a Tembien district of the Tigray Region of Ethiopia. The ''tabia'' centre is in Kelkele village, located approximately 16 km northeast of the ''woreda'' town Hagere Selam. Geography T ...

and Haddinnet.

Trekking along the river

Trekking routes have been established across and along this river. The tracks are not marked on the ground but can be followed using downloaded .GPX files. * Trek 1, from the spring area of Azef river to its mouth in

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. Characteristics It is a confined ephemeral river, locally meandering in its n ...

, largely following the edge of the Azef gorge In the rainy season, flash floods may occur in

and it is advised not to follow the river bed. At times it may be impossible to cross the Agefet river in the rainy season.

References

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