8.1 The Need for Artificial Recharge- Setting the Scene
Plettenberg Bay is a popular tourist destination along the garden route on the Cape South Coast (Figure 38). It has a local population of 29,000 (2011 census), but there is a large tourist influx and a large proportion of second homes used exclusively during peak holiday periods around December. It is typified by an extremely mild maritime temperate climate with few extremes of rainfall or temperature. Average rainfall is 945 mm/year (Wikipedia, 2016). Past periods of inadequate supply in towns along the Cape South Coast must be seen as institutional rather than hydrological. A summary of the Plettenberg system is provided in Table 9.
Figure 38 – Plettenberg Bay.
Table 9 – Plettenberg Bay scheme.
| Name of scheme | Plettenberg Bay |
| Location | Plettenberg Bay, Southern Cape, South Africa |
| Mean annual rainfall | 945 mm/year |
| Source of water | River water |
| Type of aquifer | Hard rock (quartz-arenites) aquifer |
| End use of water | Domestic supply |
| Type of managed aquifer recharge | Borehole injection |
| Current average volume of water recharged | Feasibility: injection rate > 10 L/s 0.4 Mm3/year (over 3 months) |
| Volume of water recovered | 0.8 Mm3/year (over 5 peak months) |
| Year commenced | Not yet (pre-feasibility in 2007) |
| Owner/management of scheme | Bitou Local Municipality |
| Unique attributes of this MAR scheme | Injection during winter for peak demand period in summer; capital costs one third of desalination plant. |
Plettenberg Bay has both a high demand for water in the summer and a surplus of water in the winter, making it potentially a good candidate for artificial recharge. The main objective of artificial recharge in this case would be to allow an aquifer to deliver more water during times of peak demand than would otherwise be possible. An artificial recharge assessment was conducted in 2007 (Murray, 2007) with the idea of injecting water from the Keurbooms River, which discharges into the bay, into an aquifer already tapped by the Bitou municipality, the responsible local authority within the Eden District Municipality (Figure 39).
Figure 39 – Eden District Municipality, Western Cape, including Bitou and Knysna local municipalities (EMG, 2011).
Despite an excellent MAR pre-feasibility study to which a number of different parties contributed, implementation has not taken place, more than ten years later. Because of a similar failure to consider MAR at the neighboring Knysna municipality and because of implications for the whole coastal region, the Plettenberg Bay case study is included. Discussion of the existing water resource governance framework can hopefully add insight to the evaluation of remaining bottlenecks discussed in Section 9.2 “Roll-Out of the Artificial Recharge Strategy”.