5.1 The Need for Artificial Recharge- Setting the Scene
Langebaan is located approximately 100 km north of Cape Town, along the west coast of South Africa. The Berg River is the dominant perennial river in the region, draining north-westerly into the Atlantic Ocean. The Mediterranean climate of the region (DWAF, 2008) has warm dry summers and cool wet winters, with mean annual precipitation from 310 to 400 mm. Rainfall generally occurs between the months of May through August. A summary of the Langebaan system is provided in Table 5.
Table 5 – Langebaan Scheme.
| Name of scheme | Langebaan |
| Location | Cape West Coast, South Africa |
| Mean annual rainfall | 310-400 mm/year |
| Source of water | Secondary treated wastewater and excess river water |
| Type of aquifer | Layered sedimentary aquifer, unconfined and confined, plus bedrock aquifer |
| End use of water | Industrial and domestic use |
| Type of managed aquifer recharge | Proposed to be a combination of infiltration basins and borehole injection |
| Current average volume of water recharged | Testing phase – 14 Mm3/year envisaged |
| Volume of water recovered | Still in testing phase |
| Year commenced | Not yet commenced – testing since 2008/2009 |
| Owner/management of scheme | West Coast District Municipality |
| Unique attributes of this MAR scheme | Primary and secondary aquifer; participation of large stakeholder group essential |
Water Resources Planning Leads to MAR
The towns along the west coast of South Africa have struggled with water shortages due to extreme drought weather conditions since 2014. The national Department of Water Affairs and Sanitation’s regional water supply strategy envisioned a reduction in the reliance on surface water through the provision of 14 Mm3/year to the water supply system from local aquifers.
Early work (2008/2009) in this area to test the feasibility of MAR by injection was funded by the Department of Water Affairs and Sanitation (then Department of Water Affairs and Forestry). Recent research work is funded by the Water Research Commission and implementation is funded by the Saldanha Bay municipality. This case study is based on reports by the WRC project team.
The decision to use MAR was informed by periodic studies of the Langebaan Road Aquifer System and the adjacent coastal aquifers on the west coast by the Geological Survey and the Department of Water Affairs. As a result of this work, the Saldanha Subterranean Government Water Control Area was declared in September 1976 to protect this strategic resource for future urban and industrial use. A 2008/2009 investigation by the CSIR (Council for Scientific and Industrial Research), carried out for the then Department of Water Affairs and Forestry, proposed to pursue MAR at the already established wellfield at Langebaan Road as part of a suite of suitable and appropriate water supply augmentation schemes for the sub-region based on sustainability principles for the west coast (Seyler et al., 2016; Tredoux and Engelbrecht, 2009).
The Langebaan Road wellfield had already been initiated for one of the local municipalities, Saldanha Bay, during the early 1990s. It has four production boreholes, authorized to withdraw 1.46 Mm3/year (4000 m3/d) as indicated by the West Coast District Municipality (2005). The planned 14 Mm3/year was to be met from the Langebaan Road Aquifer System, operated conjunctively with MAR and with development of a wellfield in the as yet untapped Elandsfontyn Aquifer System (Figure 20) as reported by the West Coast District Municipality (2009). The strategy proposed that by 2021 excess winter runoff from the Berg River would be stored in the aquifer in the winter months and be used in the summer months when the water demand is higher (DWS, 2016; Seyler et al., 2008).
Figure 20 – Cape West Coast of South Africa including the Langebaan Road and Elandsfontyn aquifer systems (Du Plessis, 2009).