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

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 Impingement implies there is some effect on the

groundwater resource this may be beneficial or

detrimental, water quality or available quantity

may change, changes may be temporary or

permanent.

Zone Description Threat Hazard & Consequences

related to the Atlantis aquifer

and bulk water supply

Controls required Current Impingements on the groundwater

resource

0 Borehole protection zone, in the

immediate surroundings of a an

abstraction borehole or well

Pollution could or will very soon

or even immediately enter the

borehole and be pumped out

into the water supply

The hazard is at a maximum,

with inevitble pollution of the

water at source

Access control to the zone must be

maintained and any activities must follow

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.

Unfenced site and difficulties in controlling access

and activities

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.

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.

2 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 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.

3 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

toward the zone 2 area, low

towards the zone 4, very low

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.

Must be protected by means of specific

land use planning and urban stormwater

management policies.

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.

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

Assumptions and caveats. The aquifer is assumed to be controlled by dividing compartments which are basin structures of aeolian and marine sands

which results in inhomogeneous aquifer properties and preferential flow paths. Monitoring information is necessary to determine water levels and

drawdown due to groundwater abstraction. Flow paths can be modeled in a broad sense only and therefore a conservative approach is taken to maximize

the protection area for future groundwater abstraction development.

ATLANTIS WATER SUPPLY SCHEME

RISKS & ACTIONS TO REMEDY WATER SHORTAGES & ENHANCE WELLFIELD MANAGEMENT

ITEM PROBLEM ACTION REQUIRED FUNCTIONARIES RISK RISK CONTROL PRIORITY RANK

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

Cannot resolve water

balance

Check all meters for

accuracy

Urgent to

improve

borehole

mangement

& early

warning2 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

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.

Cannot resolve water

balance and

accurately assess

yield performance of

the bhole

Service all meters

and double check

using the alternative

flow measuring

Urgent to

improve

borehole

mangement

& early

warning

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

Plant manager and

operational staff to

service the

equipment and to

ensure that the

readings are taken

properly and

regularly.

Cannot assess the

reliability of the bhole

and the operational

control or strategy

Service all hour

meters and double

check using the

SCADA trending

Urgent to

improve

borehole

mangement

& early

warning

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

emergency plan and

rehabilitation contract

Cannot increase

supply to the system

to meet water

demand. Under-

utilisation of the

wellfields

Regular borehole

maintenance and

monitoring requied in

an integrated

management

strategy, including

bhole rehabilitation

programme

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

Flooding of the low

lying areas in

Witzands causing

environmental issues.

Loss of stored

groundwater resource

Optimise the

groundwater

abstraction with an

intergrated water use

stategy.

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

Pella compromises

security of supply.

Pella and Mamre

reticulation are at

highest risk of

outages if the Pella40

drops in level

Repair the leaks.

Optimise storage by

keeping Pella10 filled

Urgent &

necessary to

resolve

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 running of

the pumping system

and optimising

control of resource

utilisation

Urgent &

necessary to

resolve

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

recharge water arising from

stormwater & treated wastewater

effluent

Monitoring and identification of

organics, pharmaceuticals,

residual products and tracers

Bulk Water area manager

and Scientific Services

Accumulation of

pollutants and toxicity,

Surface and

groundwater pollution

Regular sampling in

boreholes associated with

the recharge pathways

Current to

long term

concern

2 Contaminants in recharge water

arising from point sources within

the natural recharge area

Monitoring and identification of

representative pollutants &

tracers

Ditto Ditto Regular sampling in

boreholes associated with

the recharge pathways

Ditto

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

boreholes associated with

the possible flow

pathways adjacent to the

pipeline route

Ditto

4 Farming activities Monitoring of nitrates, pesticides

and stock feed related

phamaceuticals

Bulk Water, Scientific

Services, Planning,

Development Control

Ditto Regular sampling in

boreholes associated with

the recharge pathways

Ditto

5 Recreational activities on the

white dune s and other natural

recharge areas

Monitoring of activities and signs

of pollution from humans &

vehicles

BW area manager, plant

manager and environemntal

control officers

Ditto Regular sampling in

boreholes associated with

the recharge pathways

and clearnce of any

dumped waste

Ditto

6 Residential development Stormwater management &

pollution control

Transport Roads Stormwater

, Urban Planning ,

Development Control,

Ditto Water Sensitive Urban

Design implementation

Ditto

7 Industrial development Ditto Ditto Ditto Ditto Ditto

8 Wastewater reticulation Waterbourne sewerage &

maintenance

Ditto Ditto Ditto Ditto

9 Refuse and solid waste

management

Refuse disposal outside of

protection zone

Solid Waste Ditto Prevention of uncontrolled

dumping

Ditto

10 Alien vegetation Conrolled removal Envio Resource Management Fires, water loss Alien removal programme Ditto