Feasibility And Implementation Plan For Groundwater Resource Development Of The Malmani Dolomites Within The Olifants River Water Supply System

The Reconciliation Strategy for the Olifants River Water Supply System (ORWSS) indicated that the surface water resources in the Olifants Water Management Area are already overallocated, and recommended that the potential of the Malmani Subgroup dolomites along the Limpopo and Mpumalanga escarpment as an additional water resource be investigated. The Feasibility Study for Groundwater Resource Development of the Malmani Dolomites within the ORWSS considered among other aspects the hydrogeology, hydrology, artificial recharge potential, groundwater - surface water interaction and wellfield design options. A key aspect of the analysis and study findings was determining the amount of water that can be provided additionally, as the groundwater development was conceived as impacting on and reducing the ORWSS system yield. Hence, the implementation strategy was designed to address this mistrust in the groundwater potential and to allow for increasing the confidence in the yield estimates over time. The implementation strategy identified several possible recipients of the water, influencing the prioritisation of wellfield development. The scheduling of implementation should first address community water supply shortfalls in the area, followed by releases to the Olifants River to cater for environmental requirements and then direct development for bulk water supply schemes. Out of the twelve identified wellfield target zones (WFTZ), eleven are recommended for potential wellfield development. Seven Malmani Subgroup dolomite aquifer WFTZs have high groundwater development potential with proven high borehole yields (>10 l/s) and are recommended for priority full-scale wellfield development, through a phased monitor-model-manage approach. The total proposed groundwater development comprises 48 wellfields with a combined yield of >40 million m3/a. Although several organisations are suitable for implementing the scheme, or parts thereof, the DWS should maintain oversight function to ensure that the several parts of the scheme development are implemented in a coherent manner and in accordance to the implementation strategy.