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province are the Shu-shu Spring in the bed of the Tugela River below Kranskop, the Lilani
Spring in the Upper Mvoti Valley south of Kranskop, and the Natal Spa Spring on the
Bivane River, south of Paulpietersburg.
Springs are numerous, particularly in the higher rainfall regions of the province, and in rural
KwaZulu are an important source of water. The main disadvantage of springs isthat yields
are often seasonally variable. Secondly, springs (unless protected), are susceptible to
contamination by livestock. Protection however, does not prevent subsurface pollution
due to poorly sited pit latrines. Springs are most frequently associated with basal contacts
of intrusive Karoo dolerite sheets, the margins of dolerite dykes, faults, major joints, and
the bedding planes of sandstone rock - where these features intersect the ground surface
below higher-lying areas (which act as the groundwater reservoirs to the springs).
11.8 Methods of groundwater location
Due to the prevailing topographic conditions (which give rise to shallow soil cover), the
geology of Natal/KwaZulu is ·visible·, and borehole location can normally be undertaken
in terms of directly observable geological characteristics. In some instances, geological
field observations can be improved by the use of geological maps where these are available
at a sufficiently detailed scale. Geological maps of virtually the entire province have been
published at a scale of 1 : 250 000 (see the chapter on geology). Certain maps with a
scale of 1 : 50 000 are likewise available.
Groundwater surveys are facilitated by the use of suitable single or stereoscopic air photos
- from which features such as faults and dolerite dykes visible thereon - can be accurately
located on the ground. Orthophotos can also be used. Less useful are satellite images,
on which, because of their large scale, only broad features such as major faults and
lineaments can be discerned, these features also being readily apparent on air photographs.
Where no specific local hydrogeological information can be gleaned, either from geological
maps or direct on site observation, recourse can be made to a number of geophysical
methods of investigation to establish likely hydrogeological conditions. These methods
however, are expensive. Accordingly, those techniques which are rapid, are used in
preference to more time consuming and hence more costly procedures. The various
geophysical methods of hydrogeological investigation and their relevance in NatallKwaZulu