The Atlantis Water Supply
Scheme
“Witzands Aquifer: Sustainablity
and Protection”
Focusing on policy issues related to
sustainability and aquifer protection
Atlantis Aquifer protection zones
The zones are based on the surface and basement topography as well as the
likely travel time for pollutants to reach the wellfields
Bulk Water Branch : Policy
Broad framework for Atlantis Water Supply
• Maximise groundwater potential as a water source
• Maximise recharge of high quality, natural and
artificial
• Minimise pollution treats and epidemiological risks
• Insist on Water Sensitive Urban Design
infrastructure development for Atlantis
• Optimise the importation of surface water
• Monitor, model and optimise the aquifer
management
ATLANTIS GROUNDWATER MODEL
Groundwater Protection Zones
The protection zones are set up to inform planning and control functions within the CCT of the threats, hazards and consequence of groundwater
pollution on the bulk water supply to Atlantis, in particular the abstraction of potable groundwater used as the primary source of water in the Atlantis
Water Supply Scheme. Finally the controls required are set out for each zone
Specific land use planning and stormwater
management policies relate to the reuse of
wastewater and stormwater drainage in the
Atlantis managed artificial recharge scheme
context
Assumptions and caveats. The aquifer is assumed to be controlled by dividing compartments which are basin structures of aeolian and marine sands
Impingement implies there is some effect on the
which results in inhomogeneous aquifer properties and preferential flow paths. Monitoring information is necessary to determine water levels and
groundwater resource this may be beneficial or
drawdown due to groundwater abstraction. Flow paths can be modeled in a broad sense only and therefore a conservative approach is taken to maximize detrimental, water quality or available quantity
the protection area for future groundwater abstraction development.
may change, changes may be temporary or
permanent.
Zone
Description
Threat
Hazard & Consequences
Controls required
related to the Atlantis aquifer
and bulk water supply
Current Impingements on the groundwater
resource
0
Borehole protection zone, in the Pollution could or will very soon The hazard is at a maximum,
immediate surroundings of a an or even immediately enter the
with inevitble pollution of the
abstraction borehole or well
borehole and be pumped out
water at source
into the water supply
Access control to the zone must be
Unfenced site and difficulties in controlling access
maintained and any activities must follow
and activities
an environmental management plan. The
well head must be properly sealed against
entry of surface water and foreigbn objects
etc. A sanitary seal must be inplace in the
borehole construction.
1
Aquifer primary protection zone,
or core area. Potable water is
abstracted in this zone which
has direct hydraulic
connections and short travel
and residence times in the
aquifer to the production
wellfield area. Anywhere in this
area production wellfields are
most vulnerable to surface and
groundwater pollution.
Maximum protection is required
to avoid contamination. Natural
recharge occurs in this area
primarily, which can be
augmented by high quality
artificial recharge.
Aquifer secondary protection
zone. Groundwater in this zone
will travel to the primary
protection zone depending the
drawdown in the primary zone
and specific flow paths. Natural
recharge occurs in this area
primarily, which can be
augmented by controlled quality
artificial recharge
Pollution by either diffuse or
point sources will enter the
wellfield. Little or no pollution
attenuation can be expected.
The hazard rating is very high.
Groundwater quality will be
affected resulting in
abandonment of the well or
wellfield at worst. Remediation
will be costly and may not
necessarily result in the
wellfield being returned to
production.
Must be protected as a water catchment
area and as much as possible without
urban development or farming, ideally as a
natural area. Access should be controlled
and the area fenced. Suitable activities
must generate zero surface or
groundwater pollution. Continuous water
quality monitoring required. All
groundwater abstraction must be licensed
and strictly controlled in terms of the
National Water Act.
Production boreholes for potable water supply.
Artificial recharge is practiced in the Witzands
area. Witzands dunes are impacted by film
company and 4x4 access permits being issued.
The Chevron oil pipeline passes directly upstream
of the two wellfields. Fencing is inadequate to
control entry and not all of the area is under the
control of CCT or owned by CCT. Small scale
animal farming is active in the Silwerstroom East
corner.
Pollution by either diffuse or
point sources will enter the
wellfield over time. Some
attenuation may be possible,
depending on travel time, but
cannot be relied upon.
The hazard rating is high.
Groundwater quality will be
affected resulting in
abandonment of the well or
wellfield at worst. Remediation
will be costly and may not
necessarily result in the
wellfield being returned to
production.
Must be protected as a water catchment
area by means of specific land use
planning and urban stormwater
management policies. Activities must
generate zero surface or groundwater
pollution. Continuous water quality
monitoring required. All groundwater
abstraction must be licensed and strictly
controlled in terms of the Water Act.
Artificial recharge of saline water is practiced in
coastal strip of Witzands area. The Chevron oil
pipeline passes through the zone. Fencing is
inadequate to control entry and not all of the area
is under the control of CCT or owned by CCT. The
abandoned Atlantis solid waste dump exists in
the Witzands area NEast of the dunes and an
active sand mine and foundry waste dump is in
the East area. Small scale animal farming is
active in the Silwerstroom East corner. Westfleur
WWTP is in the East part of Witzands. The
Atlantis industrial area is in the zone. Koeberg
NPP and Akerlig OCPP are in the zone.
Buffer to the aquifer protection
zones 1 & 2. This buffer depicts
the implied boundaries of the
aquifer compartments, based
on implied basement
topography derived from
geophysics remote sensing.
Pollution in this buffer zone
could conceivably migrate into
the aquifer over time, depending
in groundwater levels in the
adjacent compartments.
Groundwater may cross over
the buffer to an adjacent
compartment as the
compartment boundaries are
not hydraulic barriers.
The hazard rating is medium
Must be protected by means of specific
toward the zone 2 area, low
land use planning and urban stormwater
towards the zone 4, very low
management policies.
towards zone 6. Groundwater
quality will be affected
depending on flow paths and
groundwater levels.
Remediation will be costly and
may not necessarily result in
acceptable groundwater quality.
The abandoned Atlantis solid waste dump exists
in the Witzands area NEast of the dunes. Small
scale animal farming is active in the Silwerstroom
East corner. The Atlantis industrial area is in the
zone.
2
3
ATLANTIS WATER SUPPLY SCHEME
RISKS & ACTIONS
ITEM
TO REMEDY WATER SHORTAGES & ENHANCE WELLFIELD MANAGEMENT
PROBLEM
ACTION REQUIRED
RISK
RISK CONTROL
PRIORITY
1
Inaccurate bulk incoming and
outgoing flow records &
reporting to HO
Daily meter readings of the
actual meter reading must be
submitted as well as the
subtraction. Existing reporting
sheet to be amended
Area manager to
instruct plant
manager
FUNCTIONARIES
Cannot resolve water
balance
Check all meters for
accuracy
2
Inaccurate bhole flow records &
reporting to HO. The type of
meter suited to the bio-clogging
conditions has accuracy
limitations, however it is easily
cleaned or serviced.
Monthly production records
must be improved. Alternative
flow meaurements must be
taken, ie orifice meter using two
pressure gauges or volumetric
discharge into a 200l drum
Cannot resolve water
balance and
accurately assess
yield performance of
the bhole
Service all meters
and double check
using the alternative
flow measuring
3
Inaccurate & missing bhole
pump running records &
reporting to HO
Monthly production records
must be improved. Running
hours must be recorded either
manuall via SCADA or on the
running hour meter in the panel.
Reasons for outages must be
clear and corrective
maintenance properly
documented. If necessary the
SCADA trending must be added
to log the pump running history
Area manager to
instruct plant
manager. Plant
manager and
operational staff to
clean and service the
equipment and to
institute the
alternative
measurements and
to ensure that the
readings are taken
properly and
regularly.
Plant manager and
operational staff to
service the
equipment and to
ensure that the
readings are taken
properly and
regularly.
Urgent to
improve
borehole
mangement
& early
warning
Urgent to
Cannot assess the
reliability of the bhole
and the operational
control or strategy
Service all hour
meters and double
check using the
SCADA trending
4
Loss of borehole yield
Implement volumetric flow tests
and measure drawdowns were
the bhole is in operation. Do
step drwdown tests for all
boreholes. Implement
rehabilitation work
Managers to set up
Cannot increase
emergency plan and
supply to the system
rehabilitation contract to meet water
demand. Underutilisation of the
wellfields
Most urgent
to resolve
5
High water table in Witzands
wellfield
Test bholes and attempt to
pump continuously. Consider
diverting flow to the
Donkergat/Zout river
catchment.Repair any damaged
power supply to the boreholes.
Atlantis Aquifer Management
Committee must be
reconstituted to involve all CCT
& ESCOM role players & CSIR
Area manager to
instruct plant
manager. Area
manager & ESCOM
to resolve issues.
Managers report to
enable the
AAMComm & CSIR
involvement. Plant
manger and
Blaauwberg Electrical
maintenance
Current to
long term
concern
6
Pella10 out of service
Test the leakage of the
reservoir. Implement repair work.
Consider viability of keeping in
service despite water loss.
Change pipework to dedicate
supply to high lying areas in
Pella & Mamre.
Area manager to
instruct plant
manager. Managers
to set up repair
contract
Single reservoir at
Repair the leaks.
Urgent &
Pella compromises
Optimise storage by
necessary to
security of supply.
keeping Pella10 filled resolve
Pella and Mamre
reticulation are at
highest risk of
outages if the Pella40
drops in level
7
Silwerstroom not supplying to
Pella40
Service the pumping system
and put into operation. Inform
the resort that supply will be
restricted to a set volume.
Plant manager and
resort manager.
Operational
maintenance staff.
Loss of potential
supply to Pella40
Regular borehole
maintenance and
monitoring requied in
an integrated
management
strategy, including
bhole rehabilitation
programme
Flooding of the low
Optimise the
lying areas in
groundwater
Witzands causing
abstraction with an
environmental issues. intergrated water use
Loss of stored
stategy.
groundwater resource
Regular running of
the pumping system
and optimising
control of resource
utilisation
improve
borehole
mangement
& early
warning
Urgent to
improve
borehole
mangement
& early
warning
Urgent &
necessary to
resolve
RANK
ATLANTIS WATER SUPPLY SCHEME
RISKS & ACTIONS TO PROTECT THE AQUIFER & WELLFIELD
ITEM PROBLEM
ACTION REQUIRED
FUNCTIONARIES
RISK
RISK CONTROL
PRIORITY RANK
1
Contaminants in managed
Monitoring and identification of
recharge water arising from
organics, pharmaceuticals,
stormwater & treated wastewater residual products and tracers
effluent
Bulk Water area manager
and Scientific Services
Accumulation of
Regular sampling in
Current to
pollutants and toxicity, boreholes associated with long term
Surface and
the recharge pathways
concern
groundwater pollution
2
Contaminants in recharge water Monitoring and identification of
arising from point sources within representative pollutants &
the natural recharge area
tracers
Ditto
Ditto
Regular sampling in
Ditto
boreholes associated with
the recharge pathways
3
Oil pipeline leaks
Monitoring of petrochemical
tracers & signs of oil pollution
Bulk Water and Scientific
Services, Oil Industry
Corrosion Group, PetroSA
and Chevron
Ditto
Regular sampling in
Ditto
boreholes associated with
the possible flow
pathways adjacent to the
pipeline route
4
Farming activities
Monitoring of nitrates, pesticides Bulk Water, Scientific
and stock feed related
Services, Planning,
phamaceuticals
Development Control
Ditto
Regular sampling in
Ditto
boreholes associated with
the recharge pathways
5
Recreational activities on the
white dune s and other natural
recharge areas
Monitoring of activities and signs BW area manager, plant
Ditto
of pollution from humans &
manager and environemntal
vehicles
control officers
Regular sampling in
Ditto
boreholes associated with
the recharge pathways
and clearnce of any
dumped waste
6
Residential development
Stormwater management &
pollution control
Transport Roads Stormwater Ditto
, Urban Planning ,
Development Control,
Water Sensitive Urban
Design implementation
Ditto
7
8
Industrial development
Wastewater reticulation
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
Ditto
9
Refuse and solid waste
management
Alien vegetation
Ditto
Waterbourne sewerage &
maintenance
Refuse disposal outside of
protection zone
Conrolled removal
Solid Waste
Ditto
Prevention of uncontrolled Ditto
dumping
Alien removal programme Ditto
10
Envio Resource Management Fires, water loss