The presently authorized groundwater use of 11.5 L/s (about 1,000 m³/day) from the Kwanokathula Aquifer could potentially be tripled to about 3,000 m³/day through MAR. The aquifer would need to hold the recharged water from winter when it is recharged until summer when the water is abstracted again during the peak season. The summer peak demand for Plettenberg Bay is 12 to 13 million liters/day and the peak week Christmas-New Year is 17 to 18 million liters/day. The water supply scheme elements are shown in Figure 43. The MAR pre-feasibility study indicated how the scheme could be expanded (Figure 44).

Figure 43 – Schematic diagram of the existing water supply arrangements for Greater Plettenberg Bay (Murray, 2007).

Figure 44 – Kwanokathula’s existing and planned boreholes (Murray and Ravenscroft, 2010). Existing abstraction = yellow; planned abstraction = dark green; planned injection = bright green; planned monitoring = orange.

The study also indicated how peak demand could be met through incorporation of MAR into the Plettenberg Bay supply system (Table 11). Injection would take place July-September and abstraction November-March, with rest periods in between.

Table 11 – Existing and proposed water supply for Plettenberg Bay (after Murray and Ravenscroft, 2010).

MAR Cost Comparison with Desalination

The estimated cost of the proposed option is approximately US$ 1.8 million. It was proposed that the project be implemented in phases with the first phase targeted for completion in 2013. The MAR capital cost is about a third of the current cost of desalination plants, which would serve a similar application of being used only during the peak demand periods. The operational costs of artificial recharge are also expected to be considerably less than desalination (Murray and Ravenscroft, 2010).