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relatively thin veneer of younger unconsolidated sediments. The siltstones of the
sediments are poorly bedded and widely but weakly jointed, with no significant structures
therein such as faults, folds, etc. Accordingly, little, if any groundwater and no crude oil
or gas (which has been drilled for in these formations both on-shore and off-shore), has
been found. Where groundwater is encountered in such formations, it is usually highly
saline with a TDS content of the order of 5 000 mg (", and more.
01 Uloa Formation (Miocene)
This thin shelly and sandy limestone formation overlies the Cretaceous sediments, and
underlies the virtually impermeable Port Durnford Formation, in places on the Zululand
Coastal Plain. Due to the presence of solution cavities (where foundl, the formation is a
very good aquifer (effectively a primary aquifer), with yields in the range of 5 - 10m 3 h-'
being derived from the few boreholes that have intersected the formation. Water quality
in this aquifer is usually good with a TDS content normally less than about 750 mg r'.
(k) Port Durnford Formation lPleistocene)
This unconsolidated formation which underlies much of the Zululand Coastal Plain at
shallow depths - on account of the clayiness of its lower member - is virtually impermeable
and thus carries no groundwater. Due to the impermeability of the lower member, a water
table is normally located in the lower portion ofthe sandy upper member of the formation,
or in the sands of the surface KwaMbonambi Formation, which also overlies the Port
Durnford Formation in many parts of the coastal plain (the perched groundwater in these
sands occurring in a primary aquifer as considered above).
In essence, the study and location of groundwater in South Africa generally, is highly
complex and there are seldom "firm guarantees" that groundwater in the required volumes
or possibly quality can be abstracted at any specific site. A brief overview of the
groundwater potential of Natal/KwaZulu with reference to bioclimatic group (see the
chapter on catchmentsl is provided in Table K2.