Addi Azmera is a tabia or municipality in the Dogu'a Tembien district of the Tigray Region of Ethiopia. The name refers to good spring rains (“azmera”), in relation to the local microclimate. The tabia centre is in Tukhul town, located approximately half-way between the woreda town Hagere Selam and the regional capital Mekelle.
Geography
The tabia stretches on both sides of the main road that climbs towards Dogu’a Tembien after passing the bridge on Giba River. The highest location are the upper slopes of Imba Dogu’a (2590 m a.s.l.) and the lowest place along Giba River (1750 m a.s.l.). It comprises cultivated plains and steeper slopes, with often good vegetation (re)growth.
Geology
From the higher to the lower locations, the following geological formations are present: Mekelle Dolerite Amba Aradam Formation Agula Shale - there are gypsum quarries in this formation, exploited by the cement factory of Mekelle Antalo Limestone – many quarries for building stones and gravel Quaternary alluvium and freshwater tufa
Geomorphology and soils
The main geomorphic unit is the gently undulating Agula shale plateau with dolerite. Corresponding soil types are: Dominant soil type: stony, dark cracking clays with good natural fertility (Vertic Cambisol) Associated soil types rock outcrops, stony and shallow soils (Lithic Leptosol) red-brownish loamy soils with good natural fertility (Chromic Luvisol) Inclusions deep, dark cracking clays on calcaric material with good fertility but poor drainage (Vertisol)
Rainfall in Addi Azmera
Due to its great difference in elevation, with slopes turned towards the wind direction (from east) during the short spring rains, orographic rains occur in that season. This results in sufficient soil moisture for growing crops in that season. In such years with good spring rains (locally called “Azmera”) the whole plain, from Qarano to Afedena is sown with “azmera” crops, particularly sorghum. Hence the name “Addi Azmera”.
Springs
Besides Giba River at the eastern (lower) side of the tabia, there are no permanent rivers. Hence the presence of springs is of utmost importance for the local people. However, in relation to the overall presence of limestone, there are only very few strong springs: Arba’ite Insessa in Zerfenti May Egam in Zerfenti
Reservoirs
In this area with rains that last only for a couple of months per year, reservoirs of different sizes allow harvesting runoff from the rainy season for further use in the dry season. Overall they suffer from siltation. Yet, they strongly contribute to greening the landscape, either through irrigation or seepage water. Main reservoirs are: Lake Giba, a 350 million m³ reservoir under construction on Giba river, just before it enters the tabia. The reservoir is mainly intended to provide water to Mekelle. This large lake, once established, will strongly impact the lower part of Addi Azmera. Indeed, the lithology of the dam building site is Antalo Limestone. Part of its water is anticipated to be lost through seepage; the positive side-effect is that this will contribute to groundwater recharge in the downstream areas, which largely belong to Addi Azmera. Traditional surface water harvesting ponds, particularly in places without permanent springs, called rahaya Horoyo, household ponds, recently constructed through campaigns
Vegetation and exclosures
The tabia holds several exclosures, areas that are set aside for regreening. Wood harvesting and livestock range are not allowed there. Besides effects on biodiversity, water infiltration, protection from flooding, sediment deposition, carbon sequestration, people commonly have economic benefits from these exclosures through grass harvesting, beekeeping and other non-timber forest products. The local inhabitants also consider it as “land set aside for future generations”. In this tabia, some exclosures are managed by the EthioTrees project. They have as an additional benefit that the villagers receive carbon credits for the sequestered CO2, as part of a carbon offset programme. The revenues are then reinvested in the villages, according to the priorities of the communities; it may be for an additional class in the village school, a water pond, or conservation in the exclosures. The following exclosures are managed by the Ethiotrees project in Addi Azmera: Afedena (exclosure), near the homonymous village (62.92 ha) Sesemat (exclosure), near the homonymous village (48.01 ha) Tukhul (exclosure), near the homonymous village (35.92 ha)