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data before and after the drought in
the Western Cape. The lowest water
levels ever measured (from 2008 to
2018) were recorded in June 2018, and
levels are starting to recover from that
level. Whether these lowest water
levels represent a real impact, largely
depends on how we define where
exactly the bottom of the aquifer is.
Various hydrogeological consultants
in the Western Cape not only attended
the day, but also presented very recent
and current data from groundwater
resource assessment studies in
which they are involved. Some of the
comments and conclusions about the
impact of the drought on groundwater
that all consultants agreed on, include:
• There is no drought impact on
groundwater
resources,
but
definitely a drought signature in
how the aquifers respond to the
change in precipitation.
• The drier cycles of 2003–2004,
2011–2012 are showing similar
signatures as 2015–2018.
• Groundwater recharge processes
are different during the drought
conditions, compared to ‘normal’
precipitation.
• In 2018, we still experienced a
below-average rainfall season in
large parts of the Western Cape,
resulting in the drought signature
still evident in the current
groundwater level data.
• The data shared at the seminar
suggested that large users of
groundwater with monitoring
data and continuous evaluation
of the data were able to supply
groundwater through the drought
period without any significant
impact on the water level trends.
• Although some good data is
available from private consultants
and their clients, very limited data
is available to the Department of
Water and Sanitation to assess
the impacts of the drought, or for
researchers/other consultants to
build upon.
Candice Lasher-Scheepers, principal
professional officer: Geohydrology at
the City of Cape Town’s Bulk Water
Supply Department, announced an
initiative by the City and also pledged
their commitment to put all groundwater
data from any previous studies in the
metropole on the City’s website to be
accessible to any interested party.
This will ensure that future studies do
not duplicate previous ones; that it is
easier to collaborate data and compare
Water Sewage & Effluent May/June 2019
and Northern Cape. As a result, we
saw an accelerated development of
groundwater resources.
It was easy to see the impact on
our surface water resources by the
daunting pictures of especially the
Theewaterskloof Dam when it reached
a level of only 11% capacity. As the
possibility of Day Zero crept closer,
more and more individuals, businesses,
and even local government hastily
turned to groundwater use. This led
to an unprecedented increase in
boreholes being drilled in the Western
Cape. And in many cases, this ‘back
door’ water supply source has kept the
front door open for businesses to stay
economically feasible, for hospitals
to secure essential services, and for
municipalities to continue to deliver
water to its residents.
This
increased
demand
for
groundwater supply inevitably led to
people asking questions like, “Will we
destroy the groundwater source?”,
“How much water can we abstract?”,
and “Is the resource resilient to the
drought?”. Very opposing views on
the potential impact of the increased
groundwater abstraction were publicly
expressed by various specialists. In this
regard, the Department of Water and
Sanitation imposed a 45% reduction in
domestic and industrial groundwater
use and a 60% reduction in agricultural
groundwater use in Government
Gazette 41381 on 12 January 2018
for the Breede-Gouritz and Olifants-
Doorn water management areas in the
province.
Which led to this one-day symposium
on 2 November 2018.
The only way to determine the
extent of the impact of the drought on
the groundwater resources is to have
monitoring data — the hard numbers;
no speculation of whether water levels
dropped because of the drought or
whether the amount of rainfall had
an influence or not. To eliminate any
speculation, the first session of the
symposium was aptly titled ‘Show me
yours, and I’ll show you mine’; referring
to data sharing, of course.
Dr Jaco Nel, deputy director of the
Institute for Water Studies at UWC,
and also the chair of the Western
Cape Branch of the GWD, opened the
symposium with a question: Do we
need to limit the use of groundwater in
drought periods, or do we continue to
use it?
Fanus Fourie from the Department of
Water and Sanitation: National Planning
Directorate shared a statistical
perspective on the monitoring of
Two UWC-IWS students attending the
symposium: Angelo Johnson (left),
current MSc Hydrogeology student,
and Adolf October, UWC alumni, GPT
Consultants.
historical trends with current trends;
and also that future hydrogeological
projects use the same set of information
as a starting point.
Apart from sharing data, the second
session of the day was titled ‘Surprise,
surprise!’ and contained talks on
unexpected revelations that some of
the attendees encountered during
drilling or monitoring of aquifer systems.
This session induced some interesting
discussions and challenged some of
the fellow hydrogeologists’ thinking
about the hydrogeology of some areas
in the Western Cape.
About the GWD
The Ground Water Division of
the Geological Society of South
Africa (www.gwd.org.za) aims to
support the scientific understanding
of groundwater to ensure the
sustainable and scientifically sound
use thereof. It proudly advocates
for science rather than dowsing or
free-for-all use, understanding that
the hydrological cycle is intrinsically
linked and requires capable scientific
interpretation for safe long-term use.
Contact the division for professional
advice.
www.waterafrica.co.za