Introduction
The Cape Supergroup consists of :
•
|
Witteberg Group – 1700m in east to 1200m in west. Quartzitic sandstone and mudstone.
|
•
|
Bokkeveld Group – Quartzitic sandstone and mudstone. 2200-3500m thick, but thins towards the north.
|
•
|
Table Mountain Group – Sandstone and two distinct shale zones.
|
All three groups intensively folded and part of the Cape Fold Belt
Geohydrology
•
|
Table Mountain Group: Artesian water due to high peaks in mountains. High rainfall, heavy folding and fracturing results in springs. Very high yields on faults (27000-450000 l/h), especially on TMG/Bokkeveld contact.
|
•
|
Bokkeveld Group: Low quality water. High TDS are observed – 18 000 mg/l. Best yields in syncline valleys (12-25 l/s). If very weathered, joints close down and yields decrease.
|
•
|
Witteberg Group: Low quality water. In fractures in shale and quartzite.
|
•
|
Two main aquifers – Peninsula and Skurweberg
|
•
|
Aquiclude layers in between – Cederberg, Goudini and Rietvlei
|
|
