Prefeasibility Study for Managed Aquifer Recharge within the Greater Kruger National Park, Limpopo Province, South Africa.

Lourens, PJ

West of the world-renowned conservation site, Kruger National Park, lies the larger extent of the Greater Kruger National Park within the Limpopo province. Boreholes have been drilled here in the last few decades to century for the provision of water supply to game lodges, large resorts, watering holes for game viewing and also historically for agriculture and livestock. The area contains both primary and secondary aquifers classified as having yields between 0.5 and 5.0 l/s, based on the geological setting which consist of gneiss intruded by dolerite dyke swarms. A geohydrological assessment of the area revealed that groundwater quality within the project area is characterised as having an EC of 100 - 450 mS/m, which seems to link to borehole proximity to surface water systems. The Makhutswi Gneiss and Doleritic Dyke swarms are the major controlling geology of the area, with higher yielding boreholes located in close proximity to dykes and major structural lineaments (faulted / weathered zones) of the Gneiss. A major concern identified through geohydrological assessment and hydrocensus observations is that boreholes frequently dry up after a few years and require either deeper drilling / redrilling or drilling a new borehole and that the very aggressive calcium hardness in the water frequently damages equipment and leads to overall higher maintenance costs. This project investigates the feasibility of increasing recharge to the aquifer with seasonal flooding / rainfall events by constructing artificially enhanced recharge locations overlaying several doleritic dykes. This is expected to decrease the salinity and hardness of the groundwater, which will reduce operational costs. Water security will also be increased through enhanced long-term sustainability of the groundwater by balancing some of the current annual abstraction.