Three-phase approach to improve deep groundwater supply availability in the Elidar district of Afar region of Ethiopia

This study provides new evidence on the effectiveness of a combined remote sensing and hydrogeological investigation method for deep groundwater development in complex geologic and geomorphologic situations in Ethiopia. The study was undertaken in the Elidar district of the Afar region of Northern Ethiopia. Due to the water availability and vegetation in this district, the majority of the population (total population of 79,000 people and 647,000 head of cattle) are dependent on pastoralist livelihoods. The current ratio of available water supply facilities to number of beneficiaries is 1:2,323 people and 1:19,029 head of cattle. A joint UNICEF-UNESCO groundwater investigation pilot project with the objective of improving drilling success rates in the Elidar district considered a three-phase approach. In phase 1 and 2, an overlay method was developed that combined data from radar, optical remote sensing and ground measurement (geology, hydrogeology, hydrology, hydro-meteorology, and geophysics). The overlay model identified the most promising site to undertake well drilling, considering a probability of drilling wells with sufficient amount of water and permissible water quality (defined as Q = >2 L/s and EC < 2,000 μms/cm²). In phase 3, three production boreholes were drilled and the results showed a 92% accuracy against the overlay model.