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(d) The most acidic waters in South Africa are the dark-coloured Table Mountain Series
spring waters of the Cape.
(e) The purest waters are those arising in the quartzites and sandstones of the Pretoria
Series. the Witwatersrand System and the Waterberg System.
(f) Waters with the highest percentage of silica are found in the granites and in the
basic rocks of the Bushveld Igneous Complex. Waters arising in the basic rocks of
the Bushveld Igneous Complex have the highest amount of silica of all waters in
South Africa. with the exception of the few Pondoland springs.
(g) The highest percentage of sulphate is found in the Old granite waters of the north
west Cape and in Dwyka waters of the Cape. western Transvaal and Pondoland.
(h) The waters with the least variation in percentage composition are those arising in
dolomite.
(i) Group A waters are found in approximately two-fifths of South Africa. while Group
o waters are found in one-third of the country.
(j) According to Bond (1946). with the exception of highly saline waters in the
Cretaceous beds along the Natal North Coast. most of the groundwaters of Natal
are comparatively pure (mainly Group E).
11.14.2 An examination ofthe Bond (1946) classification. with comments on northern
Natal/KwaZulu
According to Van Wyk (1963)*. the classification by Bond (1946) is unreliable for most
of northern NatallKwaZulu. Van Wyk found that Bond's classification is too general to be
of much practical value. due to insufficient data and/or unrepresentative sampling
(including an over-emphasis on springs). Using the same general categories defined by
*
Discussion based on Van Wyk. W.L.• 1963. Ground-water studies in northern Natal. Zululand and
surrounding areas. Memoir No. 52, Geological Survey. Department of Mines. Pretoria. 135 p. and
map.