[1] It is mostly a confined river, locally meandering in its narrow alluvial plain, with an average slope gradient of 25 metres per kilometre.
[2] The magnitude of floods in this river has however been decreased due to interventions in its upper catchment, particularly around the May Leiba reservoir.
[5][6] On many steep slopes, exclosures have been established; the dense vegetation largely contributes to enhanced infiltration, less flooding and better baseflow.
[9] Based on crystallisation ages of its rocks in Eritrea and Ethiopia, it is estimated that the igneous activity occurred between ~850 and 740 million years ago.
The Tsaliet Group has recorded the arc volcanism and the formation of crust that later formed part of the Arabian-Nubian Shield.
[10] The Group consists of partially metamorphosed volcanic and sedimentary rocks (impure marble, slate, calcareous siltstone, sericite-chlorite schist, greywacke, and tuff), with a minimum thickness between 1500 and 2500 metres.