Groundwater quality: Ethiopia

Ethiopia, with a total area of some 1,127,000 square kilometres, is a landlocked country in East Africa, situated to the west of Somalia and north of Kenya. The terrain consists largely of high mountains and plateaux with elevations above 1500 m, divided from south-west to north-east by the East African Rift Valley, a major structural feature some 40– 60 km wide and in places 1000 m below the flanking plateau areas. The Rift extends across Ethiopia via Lakes Rudolf and Chamo in the south- west, Awasa, Nazret, Mile and Lake Afrera in the north (Figure 1). The Awash River flows along much of the northern section. The southern part of the Rift, extending between Lake Chamo and the Awash River is known as the Lakes District and is a zone with numerous lakes, largely elongated parallel to the Rift axis. Some of these are freshwater lakes while some are alkaline and saline. The floor of the Rift rises from the south-west to a maximum altitude of more than 1800 m north of Lake Zwai, beyond which it descends into the low-lying Afar section of the Rift, which is in large part below sea level. Elevation in Ethiopia varies from the highest point at Ras Deshen Terara (4620 m) to the lowest in the Danakil Depre ssion (-125 m; northern section of the Afar Depression). The Ogaden region of eastern Ethiopia (bordering Somalia) is also a flat-lying plain, with an elevation of around 600 m