In 2014, IGRAC, together with Acacia Water, carried out a project on Managed Aquifer Recharge (MAR) in the transboundary Merti Aquifer, shared between Kenya and Somalia. The project was commissioned by IGAD Inland Water Resources Management Programme (IGAD-INWRMP), which is an EU funded programme that aims at strengthening the national and regional capacities in the field of water resources management and at the development of regional dialogue and cooperation for sustainable water resources management in the Horn of Africa.
The overall goal of the project was to identify and map the potential for different MAR applications within the Merti aquifer and to develop a MAR data management system. Based on the project results recommendations were given on the potential for different MAR applications in the region.
The IGAD-INWRM team has selected the Merti aquifer, shared between Kenya and Somalia, as pilot transboundary aquifer (TBA) for this project. The Merti aquifer is a large non-renewable aquifer that is one of the few reliable water sources in this semi-arid region. Since the early 1990's there has been a significant increase in population due to the settlement of a large number of refugees from Somalia in the Dadaab area, which led to an increased demand for drinking water. For this drinking water both local population and refugees depend entirely on groundwater. However, although the Merti aquifer is a vital source of fresh water in the region, still relatively little is known about the extent of the aquifer, its hydrogeological parameters and groundwater recharge.
The study has shown that for the Merti aquifer both the water resources and landscape characteristics for MAR interventions are available. The developed MAR suitability map indicates there is potential for MAR interventions for shallow and deep groundwater. Shallow MAR interventions include diffuse land surface infiltration, localized land surface infiltration, direct aquifer infiltration, surface water storage and in-stream storage such as sand dams and subsurface dams. Given the confined nature of the Merti aquifer, the best technique for MAR of deep groundwater is use of injection wells. The final results were presented by IGRAC Researcher Nienke Ansems during the workshop on MAR technology for the Merti aquifer, which was held on 26-27 March 2015 in Naivasha, Kenya. This workshop was combined with a training session on the use of a MAR data system. The objectives were to promote the use of a data-driven approach and equip local experts with the knowledge and skills to apply MAR.
MAR Suitability mapping
MAR can be used to improve water security and resilience to droughts. The selection of suitable locations may however not be a simple task as there are many aspects which need to be considered. These include landscape characteristics, soil and aquifer properties, and the availability of excess surface water. The suitability for different MAR applications within the region can be identified and mapped to guide decision making where MAR intervention could be applied successfully. The methodology for MAR suitability applied in the Merti Aquifer can be applied in other regions to complement policy on integrated water resources management and to assist implementing parties by providing a first-pass on scheme selection.
Role of IGRAC
- Mapping the area using remote sensing and GIS analyses.
- Develop database on groundwater information in the Merti area.
- Design and development of information management system.
- Organisation of workshop on MAR technology in Merti area.