The Merti aquifer (Kenya), a sustainable water resource for the Dadaab refugee camps and local communities?

The Merti aquifer (Kenya) is the only permanent water resource for the supply of the Dadaab refugee camps and local community. Risk of well salinisation and water level depletion has led to the concerns regarding sustainability of groundwater management. A methodology was developed to quantify groundwater recharge, based on hydrogeological data analysis, linking river discharge rates to groundwater recharge by combining remote sensing techniques with surface/groundwater numerical modelling. Also, the risk of salinisation of wells was assessed by means of numerical modelling combined with data provided from a groundwater monitoring network. Groundwater recharge estimates yielded 50 to 100 times higher values than previous studies, suggesting a multi-layered aquifer system. Since abstractions are concentrated within only one aquifer horizon of the system, they were found to be close to recharge rates. Hence, groundwater prospection of deeper horizons could reveal a potential for new groundwater resources in the area.