5.4 Water Quality

The dominant water types in the coastal aquifers are NaCl and CaHCO₃ (Figure 22). There is a marked difference in salinity between the upper and lower aquifer units. In the lower aquifer unit, the electrical conductivity is commonly less than 120 mS/m, whilst in the upper aquifer unit it is generally > 250 mS/m and often exceeds 500 mS/m near the Berg River and the Saldanha Bay.

Figure 22 – Tri-linear piper plot for West Coast water samples collected in 2017/2018. LRAS is the Langebaan Regional Aquifer System and EAS is the Elandsfontyn Regional Aquifer System (Jovanovic et al., 2018).