Hydrogeology of the Nyanzari Catchment, Gitega, Burundi

Christoph Neukum1, Christian Tiberghien1, Matthias Heckmann1, Kai Hahne1, Helena Pfunt, Sara Vassolo1

P 11.6 in Beiträge zur Hydrogeologie Südamerikas und Afrikas

Burundi is a small (27,834 km²) landlocked country on the eastern flank of the Western African Rift Valley. With about 9.8 Million inhabitants and an annual growth rate near 2.4% (from census 2008, ISTEEBU), it has one of the highest population densities in Africa - about 379 inhabitants per square kilometre. Gitega, the second biggest city of Burundi (155 005 inhabitants in the commune from the census 2008) is the only city in Burundi supplied by groundwater. The main well field is located in the Nyanzari catchment, which is situated in a complex hydrogeological setting of an undifferentiated variety of heterogeneous metamorphic rocks with a strong tectonic overprint. The well field management, maintenance and protection is the biggest challenge for its sustainability. The first step is the understanding of the local hydrogeology to build a groundwater numerical flow model aimed at further studies, mainly the definition of sustainable pumping rates and groundwater protection zones.

We present hydrogeological data, results, and interpretation of the Nyanzari catchment, which have been produced in the frame of a bilateral cooperation project financed by the Federal Ministry of Cooperation and Development between the Burundian Ministère de l’Eau, l’Environnement, l’Aménagement du Territoire et de Urbanisme (MEEATU) and the German Federal Institute for Geosciences and Natural Resources (BGR).