Water Services Development Plan
Chapter 7
Future Infrastructure Requirements
of
City of Cape Town
Status: Comprehensive WSDP
www.capetown.gov.za/water/wsdp
December 2001
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Table of Contents
TABLE OF CONTENTS ...........................................................2
LIST OF TABLES .................................................................3
LIST OF FIGURES ................................................................4
LIST OF ABBREVIATIONS ......................................................5
CHAPTER 7 ........................................................................6
7 FUTURE INFRASTRUCTURE REQUIREMENTS.............................7
7.1
7.2
STATUS OF EXISTING MASTER PLANS .................................................................. 7
OVERVIEW OF PROPOSED EXPANSION TO BULK INFRASTRUCTURE ................... 8
7.3
OVERVIEW OF PROPOSED EXPANSION TO RETICULATION INFRASTRUCTURE . 15
7.2.1
7.2.2
Bulk Water ........................................................................................................ 8
Wastewater ..................................................................................................... 11
7.3.1
7.3.2
7.3.3
Water ............................................................................................................... 15
Wastewater .................................................................................................... 19
Summary of Capital Expenditure on Bulk Reticulation..........................20
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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List of Tables
Table 7.1 Current Status of Master Plans ...................................................................... 7
Table 7.2 Example: Water Master Plan of Helderberg Administration-Proposed
Projects ......................................................................................................................... 18
Table 7.3 Example: Sewer Master Plan of Helderberg Administration-Proposed
Projects .........................................................................................................................22
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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List of Figures
Figure 7.1a Required Works for Future Bulk Water Supply System ...................... 13
Figure 7.2 Example Water Master Plan: Helderberg Administration..................... 17
Figure 7.3 Example Sewer Master Plan: Helderberg Administration ..................... 21
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
List of Abbreviations
AADD
AFU
CCT
CFA
CMA
CMC
DM
DWAF
EIA
GLS
I&AP
IDP
IMEP
IWRP
MCDA
MNF
MLC
PNE
PDG
UAW
URV
WC
VIP
WDM
WSDP
WTW
WWTW
Annual Average daily demand
Automatic Flushing Urinal
City of Cape Town
Cape Flats Aquifer
Cape Metropolitan Area
Cape Metropolitan Council
Demand Management
Department of Water Affairs and Forestry
Environmental Impact Assessment
Geustyn Loubser Streicher Inc
Interested and Affected Party
Integrated Development Plan
Integrated Metropolitan Environmental Policy
Integrated Water Resource Planning
Multi-Criteria Decision Analysis
Minimum Night Flow
Metropolitan Local Council
Protected Natural Environment
Palmer Development Group
Unaccounted For Water
Unit Reference Value
Water Conservation
Ventilated Improved Pit Latrine
Water Demand Management
Water Services Development Plan
Water Treatment Works
Wastewater Treatment Works
5
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
Chapter 7
Future Infrastructure Requirements
6
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
7
7 Future Infrastructure Requirements
Issues:
• Not all administrations have comprehensive master plans (both water
and sewer);
• Inadequacy of current preventative maintenance / pipe replacement
programs
• Stormwater / groundwater infiltration in sewers
• Major bulk water and wastewater infrastructure requirements
• Siting of future Water Treatment Plants dependant on water
resource availability.
7.1 Status of Existing Master Plans
Table 7.1 indicate the status of existing Water and Sewer Master Plans as
based on the former MLC boundaries. A link to the treasury system and an
accurate unaccounted-for-water analysis was done for the areas as indicated.
Table 7.1 Current Status of Master Plans
* Does not include a future infrastructure 15 yr horizon master plan;
** Interface does exist with the bulk meter record database.
*** Moddelling and planning has been done, but no formal master plan exists.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
7.2
8
Overview of Proposed Expansion to Bulk Infrastructure
This section is currently under review and will be revised in December 2001,
since alternative options (Table Mountain Group Aquifer) for water supply are
being investigated which will impact on the location of the future water
treatment works.
7.2.1 Bulk Water
Planning Horizon:
Planning on the bulk water distribution (refer to Computer Model Analysis and
Master Plan for Bulk Water Supply System, March 2001) system has been based
on a future AADD of 1350 Ml/d which will be realised in approximately 12 to 15
years time. Conceptual planning of bulk water supply infrastructure has however
been carried out up to an AADD of 1850 Ml/d. This AADD will only be realised in
approximately 25 years time.
Raw water sources:
There is much uncertainty with regards to future raw water sources for the
Western Cape. For this reason, the CCT as part of their Master Plan for the
Bulk Water Supply System initiated a study looking at the integration of the raw
water sources supplying the CMA, and the effect the development of these raw
water resources would have on the associated bulk water supply infrastructure.
(Refer to the report entitled “ Integration of Raw Water Resources Supplying
the CMA”). A key strategic issue which has been identified is the availability and
timing of future water resources. The availability of future water resources
affects the siting and sizing of future water treatment plants, bulk distribution
pipelines and bulk storage reservoirs. Long term infrastructure planning by the
CCT and DWAF has to happen concurrently and timeously so that the two
process can inform each other.
It is imperative that an indication and commitment is obtained from DWAF as to
potential yield and timing of implementation of the Brandvlei Scheme as well as
the Molenaars River Diversion. The CCT is currently investigating the feasibility
of the Table Mountain Group Aquifer as a source of water for Cape Town.
Information pertaining to the above mentioned schemes will inform the location
and sizing of a new WTP and associated pipe infrastructure.
In addition to the TMG Aquifer, it is anticipated that the CCT will proceed with
the implementation of the Voelvlei Augmentation Scheme as was described
under the Section of the WSDP entitled "Integrated Water Resource Planning"
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Additional WTP capacity:
For full utilisation of an additional yield of 345 Ml/d (AADD planning horizon of
1350 Ml/d), additional WTP capacity of 500 Ml/d is required. (The full 500
Ml/d is used in summer peaks, but less than 345 Ml/d is used in low demand
winter months. The average utilisation equals the yield of 345 Ml/d). Provision
of the 500 Ml/d capacity was investigated at Faure-, Blackheath- and
Wemmershoek WTP’s (close to the proposed Skuifraam Dam), which are all
linked to the RSE raw water system.
The following options along with the associated bulk pipeline and bulk storage
reservoir infrastructure were investigated and costed:
1) Option 1: Installation of 500 Ml/d additional water treatment capacity at
the existing Faure WTP
2) Option 2: Installation of 140 Ml/d additional treatment capacity at
Wemmershoek WTP and an additional 360 Ml/d treatment capacity at the
existing Faure WTP
3) Option 3: Installation of a new 500 Ml/d WTP at a site near the proposed
Skuifraam Dam
Although the options still require further investigation, Option 3 at this stage is
the preferred option for the following reasons:
• A new WTP in the vicinity of Skuifraam Dam will reduce the reliance which
the CCT currently places on the RSE Tunnel System (security of supply)
• A WTP near Skuifraam Dam and associated pipework could cater for the
growing water demands of Paarl and Wellington and make available currently
under-utilised capacity in the existing pipeline from the Wemmershoek WTP.
• The WTP could feed the areas of high growth (ie Durbanville North) directly.
• It would provide an alternate source of supply to Glen Garry Reservoir and
enable the Wemmershoek WTP to be shut down for repairs or maintenance.
• Water from some of the sources could be gravitated to Glen Garry Reservoir
(as opposed to Option 1 where all the water would have to be pumped to Glen
Garry)
• Increased flexibility in the bulk supply system
The proposed schematic layout for option 3 is depicted in Figure 7.1a and Figure
7.b. Schematic layouts and a detailed description and costing of the other
options are contained in the Master Plan of the Bulk Water Supply System.
Due to the uncertainity associated with the availability of raw water resources,
it is anticipated that any new water treatment plant capacity which is required
will initially be implemented in increments of 250Ml/d.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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The siting (and possible future sizing) of future water treatment works will be
decided upon when greater clarity concerning future raw water resources comes
to hand. Refer to the report entitled “ Integration of Raw Water Resources
Supplying the CMA”.
A more detailed study examining the suitability of potential sites identified for
a possible new water treatment plant in the vicinity of the proposed Skuifraam
Dam will be undertaken 2002.
Cost estimates and phasing in of works:
The preliminary cost of Option 3, with associated bulk water supply
infrastructure and bulk storage reservoirs is in the region of R 1154,3 million.
For a detailed breakdown of the future bulk infrastructure requirements
(excluding water resource development costs and water treatment plant
upgrades and repairs), as based on the Computer Model Analysis and Master Plan
for Bulk Water Supply System, March 2001, refer to the Bulk Infrastructure
Program GO TO. The timing of the infrastructure requirements assumes that the
bulk water supplied by the CCT will follow Package 1 and 2 curve as detailed
under "Integrated Water Resource Planning" section of the WSDP. The total
cost (year 2001 value) for all the required works within the 1350 Ml/d planning
horizon is estimated at R1154,3 million (including P&G’s, contingencies and fees,
excluding VAT).
A summary of the anticipated costs for water resource development and bulk
water supply infrastructure over the next 12 to 15 years is given in the table
below:
Raw water pipelines
Additional WTP capacity
Bulk system pipelines
Additional pump capacity
Additional storage capacity
Miscellaneous other items
Sub-Total
Water Resource Development Costs
(for 6 years only)
Total
:
:
:
:
:
:
R 47,4 million
R 140,2 million
R 648,2 million
R
34,4 million
R 213,0 million
R
29,8 million
R 1 154,3 million
:
R 115,0 million
R 1 269,3 million
The three year CCT bulk water capital expenditure program is also attached GO
TO.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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7.2.2 Wastewater
The Bulk Infrastructure Program GO TO summarises the future sewer
infrastructure requirements to meet the future growth, but also to adhere to
DWAF’s new effluent standard requirements to be implemented by 2010. The
total cost of upgrading is estimated at 1.5 billion over the next 10 years, with
66% of this capital required for upgrading of the Athlone, Milnerton and
Zandvliet wastewater works.
Although it is estimated that the annual
expenditure required is in the order of R145 million, it is preferred that this
programme be implemented over a shorter period due to the current condition
of infrastructure and the requirement for increased capacity. Therefore an
expenditure of more than R100 million per annum over the next four years is
required. For more information refer to the 3 year capex program GO TO.
Strategic Bulk Wastewater Study:
The Strategic Bulk Wastewater Study (1999) assessed the performance of
existing wastewater equipment, processes and management systems and
identified where improvements were necessary for more effective performance.
In addition the development predicted to take place in the CMA over the next
20 years, identified the need for facilities to be extended or new ones to be put
in place.
The comprehensive (37 volumes) Strategic Report on Bulk Wastewater
requirements over the next 20 years forms the basis of guidance for effective
planning of conveyance and treatment of wastewater in the CMA. The basis of
the study included the following issues:
• Catchment analysis
• Performance of existing facilities
• Expected growth in the CMA over the next 20 years
• Strategic planning and prioritisation
• Environmental impacts
• Effluent re-use
• Sludge management
• Rationalisation of wastewater facilities
• Odour control
• Tariff calculation and funding requirements
For more information concerning the study refer to the synopsis of the
strategic study in the document entitled “Strategic Evaluation of Bulk
Wastewater” (Contact the CMC Administration )
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Cape Wastewater Consultants were appointed on 27/9/2001 to undertake
additional investigations into various factors that could influence the
recommendations contained in the Bulk Wastewater Study completed in 1999.
The following aspects are going to be considered in greater detail:
• Water Demand Management
• HIV/Aids
• Effluent Standards on design approach
• Rationalisation
• Evaluation of capital requirements
• Estimated Planning Horizon
• Infiltration
For more detailed description of the above-mentioned issues refer to the
document entitled “Bulk Wastewater Infrastructure”. GO TO.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
Figure 7.1a Required Works for Future Bulk Water Supply System
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WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
Figure 7.1b Required Works for Future Bulk Water Supply System (Detail)
14
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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7.3 Overview of Proposed Expansion to Reticulation Infrastructure
7.3.1 Water
The works required to ameliorate existing problems and to cater for growth in
demand have been investigated in detail in the various master plans (refer to
Table 7.1). Where no detail master plans were available the required works were
based on the Capital Infrastructure Programs of the applicable Administrative
Units. Only a brief summary of the required works is herewith provided based
on the former MLC boundaries. More detailed information is available in the
relevant master plans. An example of a water master plan as compiled for
Helderberg (2001) is included in to indicate the available information.
Blaauwberg:
Apart from general upgrading required in the Milnerton-, Melkbos- and Atlantis
zones, most of the future bulk infrastructure will be required to accommodate
the large areas earmarked for residential development to the north of Table
View. Bulk supply to this area is already limited and these future areas would
not only require major upgrading of the CMC bulk water system, but would also
require a new bulk connection, feeder main and proposed reservoir at
Contermanskloof (2 x 25 Ml) and an extension of the water network to provide
water to small holdings.
Cape Town:
Most of the available land in the former Cape Town area has already been
developed, which implies that no major bulk infrastructure will be required in
future. However, since many of the pipelines are more than a 100 years old,
most of the capital expenditure is required for the replacement of aging
infrastructure. Currently approximately 12km of pipeline is replaced each year,
which is inadequate when considering that there are more than 2000 km of
pipeline in this area which equates to a replacement period of more than 150
years.
Helderberg:
Most of the future works are required to accommodate the large areas
earmarked for future development in the Sir Lowry’s Pass and Gordons Bay
areas. Works include new reservoirs and pumping stations for the high lying
areas in Sir Lowry’s Pass and Sweetwaters. Other works include reinforcements
to the bulk supply system in Somerset West and Gordons Bay and four new CMC
connections. (Refer to Figure 7.2 and Table 7.2 under Helderberg heading).
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Tygerberg:
Apart from the capital projects required to replace and upgrade existing
infrastructure, a number of additional projects have been identified for the
short term and medium term including the upgrading of the Eksteen and Old Oak
pumping stations, the removal of mid-block pipes in Bishop Lavis, provision of
water to small holdings (Westerdale), Silverboom rising main, a new 400 mm main
in Avonwood Road. The high growth in and around Durbanville demand a new bulk
connection, bulk pipelines, a new pumpstation and a reservoir. Additional bulk
connections and pipelines are installed for developments in Delft and Mfuleni.
Oostenberg:
The Oostenberg water supply system is generally sufficient to meet the current
water demand. Large areas have been earmarked for development mainly north
of Kraaifontein (Langeberg), east of Kuils River (Zevenwacht, Hazendal) and in
the open areas surrounding Blue Downs. Apart from the bulk facilities to service
these areas, a number of existing pumping stations and feeder mains would
require upgrading including the Bloekombos, De Novo, Langeberg and Kuils River
systems. Various pumpstations require upgradings to supply high growth areas.
Storage requirements are generally sufficient to meet the future water demand,
but needs to be confirmed through the Water Master Plan currently being
compiled. It is anticipated that additional storage will be required at the
Andrag reservoirs as well as a new reservoir site to serve future areas north of
Blackheath near the Stellenbosch Arterial.
South Peninsula:
Apart from general renovations no significant upgrading of the pumping stations
are required. Additional storage is required at a number of reservoir locations
of which the most significant are Houtbay (6.5 Ml), Wynberg (40 Ml) and
Brakkloof (14.5 Ml). New bulk supply pipelines are also required in a number of
places including Pelikan Park, Vrygrond and Westlake.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
Figure 7.2 Example Water Master Plan: Helderberg Administration
17
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Table 7.2 Example: Water Master Plan of Helderberg AdministrationProposed Projects
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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7.3.2 Wastewater
The works required to ameliorate existing problems and to cater for growth in
demand have been investigated in detail in the various master plans (refer to
Table 7.1). Where no detail master plans were available the required works were
based on the Capital Infrastructure Programs of the applicable Administrative
Units. Only a brief summary of the required works is herewith provided based
on the former MLC boundaries. More detailed information is available in the
relevant master plans. An example of a sewer master plan as compiled for
Helderberg (2001) is included in to indicate the available information.
Blaauwberg:
As previously discussed, the almost 3000 ha residential land earmarked for
development north of Table View west of the N7 will require major bulk
sanitation infrastructure. Apart from the 5 new sewage pumping stations
required at Doornbach, Dunoon, Railway Bridge, Blaauwberg Bridge and
Witzands, the existing Sandown pumping station will also require upgrading. A
new outfall sewer is required for the Parklands development, while new collector
mains would be required in a number of places including Beach Boulevard, Du
Noon, Surringdale, Diep River and Witzand. The Postdam wastewater works
would also require upgrading.
Cape Town:
The available land in the Cape Town area is almost fully developed, which implies
that no major new bulk sewerage infrastructure is required. However, since
many of the systems are older than 100 years, most of the capital investment is
required for the replacement of old collapsing sewers, especially pitch fibre
pipes. Ad hoc Closed Circuit Television (CCTV) inspections are important to
determine the condition of sewers. A network will be installed in industrial areas
where septic tanks are still in operation.
Helderberg:
The capacity of the sewer reticulation system is generally adequate to
accommodate the future developments. The Gordons Bay drainage area requires
new outfall sewers to accommodate the future development areas to the northeast. The Strand/Sir Lowry’s Pass drainage area requires a new “cut-off” outfall
along the N2-route to link up with the rehabilitated Gants sewer line. The
Somerset West A- and B- Stream drainage areas require new outfall sewers to
eliminate existing pumping stations. The Macassar drainage area requires two
new outfall sewers, pumping stations and rising mains to enhance the level of
service in the Sandvlei and Kramat area. (Refer to Figure 7.3and Table 7.3).
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Tygerberg:
Apart from the replacement and upgrading of existing sewerage infrastructure a
number of short term projects have been identified including new outfall sewers
for Durbanville (Trunk sewer - Phase 4), Bishop Lavis and Parow. A number of
Vitro/Glaze sewers will also be upgraded in Bishop Lavis and Ravensmead. A
comprehensive project to replace approximately 400Km of pitch fibre pipe over
a 10 year period, started recently.
Oostenberg:
There are a few areas in Oostenberg where the bulk sewer reticulation systems
require upgrading including a new outfall sewer along Saxdowne Road and the
upgrading of the Kuilsriver Outfall to accommodate areas earmarked for
development in the Hazendal/Zevenwacht areas, while an the Brackenfell outfall
sewer (along Old Paarl Rd) also requires upgrading. The high stormwater
infiltration in Kraaifontein also needs to be addressed.
South Peninsula:
There are approximately 3000 septic tanks in operation in the South Peninsula
area. These systems, such as in Scarborough, was initially planned for smaller
developments, but as the density of septic tanks increased so did the potential
for groundwater pollution. Plans are in place to upgrade the Scarborough and
Noordhoek septic tank systems to smallbore or waterborne systems. Bulk
sanitation services are also required in Westlake, Pelican Park and Vrygrond,
while many of the existing pumping stations will require upgrading including
Raapkraal, Retreat, Rondevlei, Clifton, Glen Cairn and Fishhoek which includes
the installation of telemetry systems, variable speed pumps and the installation
of engine driven pumps.
Reticulation is required in a number of new
developments including Zeekoeivlei Phase 3, Kommetjie, Houtbay Stage 2 and in
the informal areas of Imizamo Yethu. The rehabilitation of pitch fibre pipes is
also required in a number of places.
7.3.3 Summary of Capital Expenditure on Bulk Reticulation
It is difficult to determine the future long-term capital requirements for water
and wastewater reticulation infrastructure. This is partly because not all the
areas have master plans (refer to Table 7.1), which makes it difficult to
determine the impact of growth and future developments on existing water and
sewerage systems. For the purposes of the WSDP only the short-term capital
requirements are herewith reflected as based on the recent budget exercise
for 2002/2003, i.e. R80 mil on the Water Account GO TO and R101 mil on the
Sewerage Account GO TO. Figures for the 2003/2004 and 2004/2005 financial
years have also been calculated, but only reflects the additional capital
requirement of currently identified (for 2002/2003) projects.
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
Figure 7.3 Example Sewer Master Plan: Helderberg Administration
21
WATER SERVICES DEVELOPMENT PLAN OF THE CITY OF CAPE TOWN
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Table 7.3 Example: Sewer Master Plan of Helderberg AdministrationProposed Projects