Water, Sewage & Effluent March April 2019 | Page 31

have expressed themselves against the
use of groundwater. Politicians demand
water to be piped over long distances
from sources such as the Orange River to
supply towns in the Karoo.
One of the problems of borehole
failure is that virtually no management
of the resource takes place at local
level — just pumping until it fails. The
NGS mentions that national monitoring
already indicates that the country’s
major aquifers are under pressure
in many locations through over-
abstraction, declining water levels,
and water-quality degradation. Even
hard-rock aquifers in Limpopo show
local declining trends in groundwater
levels as a result of over-abstraction.
Equally concerning is the widespread
trend of increasing nitrate levels (parts
of Limpopo, North West, and Free State
12 000 million m³/a, but more than 80%
of this is already allocated. As the
National Water Act had indicated in
1998, groundwater is indeed a ‘significant
resource’. The NGS reckons that 22% of
towns use groundwater as sole source
and another 34% in combination with
surface water.
This groundwater source is not evenly
distributed, but spread variably, often
thinly, over the whole country. This can
be an advantage in providing water for
small-scale local use, but to use it for
bulk water supply to larger centres of
demand may require a large number of
boreholes and connecting pipelines.
This may not always be economic, and
operation may be a major consideration.
There are constant reports in the media
of municipal boreholes that are running dry
or are about to fail. Municipal managers
The Department of Water and Sanitation’s National Groundwater Strategy estimates that South Africa has 7 500 million cubic metres per
year available as renewable groundwater.
innovations
is constantly handled with suspicion
through questions such as: Is there
enough groundwater? Is this invisible
source reliable?
The Department of Water and
Sanitation (DWS) aims to provide clarity in
the National Groundwater Strategy (NGS)
finalised in 2017. The NGS estimates
that South Africa has 7 500 million cubic
metres per year available as renewable
groundwater (in scientific language,
called the utilisable groundwater
exploitation potential, allowing for factors
such as physical constraints on extraction
and maximum allowable drawdown).
Current groundwater use is between
3 000 and 4 000 million m³/a. There is thus
the potential to considerably increase
groundwater supplies. In contrast, the
assured yield of South Africa’s surface
water resources is approximately
www.waterafrica.co.za
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