Objective: Minimise the use of potable water, and promote conservation of water resources
Water sustains all life on earth and, therefore, the conservation of this precious resource is a priority in water scarce regions such as Cape Town. Water conservation and water demand management could be implemented through efficient technologies and behavioural changes. For the 2010 FIFA World Cup™, the aim was to reduce water consumption, specifically potable (drinking) water, through the use of efficient fixtures, controlled irrigation and public awareness.
The use of rainwater, greywater and other non-potable sources was encouraged wherever possible, as well as the protection of water resources through the use of environmentally friendly products to clean stadia and maintain pitches. In creating new construction surfaces, the use of permeable materials for paving and walkways was also promoted.
The projects
Project actions
Identifying alternative sources of water for irrigation of Green Point Common and implementing the most feasible option
Following the decision to construct the new Cape Town Stadium and, as part of the project, to redesign the Green Point Common area, the need to provide a sustainable water supply for irrigation to ensure a green commonage with sports fields, a golf course and other landscapes was identified as a key element of the project.
While the use of potable water for irrigation was an option, the very high demand on the City’s scarce water resources would have always placed this area under risk during times of water shortages. Therefore, in 2008, the City commissioned a feasibility study for other water sources for irrigation as opposed to potable water, which had been used previously. The study investigated, among other things, desalinisation, feasibility of boreholes, greywater treatment, rainwater harvesting, and the harvesting of spring water from the slopes of Table Mountain. The study concluded that the harvesting of spring water from the Oranjezicht Springs on the slopes of Table Mountain was the most cost-effective way to reduce the use of potable water for the irrigation of the Common. At the time, the spring water ran through the stormwater network into the sea. The spring water was not potable, and would have required treatment to meet drinking-water standards.
The total amount of irrigation water required was approximately 580,12 Mℓ/year. The flow from several springs is collected in a chamber constructed in 1853. The flow in the chamber is measured as being some 22 l/s (1 900 m/day) to a maximum of about 39 l/s (3 370 m/day). This yearround rate of flow is more than sufficient to meet the annual irrigation needs of the greater Green Point Park.
The decision to use spring water for irrigation influenced the redesign of the Green Point Park, allowing the optimisation of this water source through a number of water features, including wetlands, ponds, and the demonstration and use of renewable energy. The capacity of the ponds is 25 000 m³. The water ponds collect stormwater as well as provide shortterm water storage. By optimising all the design elements and parameters, it was further possible to spread the peak water demand over a 24-hour period and to provide water under pressure, thereby limiting the need for pumping.
Low-flow irrigation fittings were installed to reduce flow rates and landscaping is predominantly indigenous, further reducing the irrigation demand peaks.
| Camissa - The Place of Sweet Waters
The history of Cape Town’s establishment as a trading post and refreshment station in 1652 is directly linked to springs as a source of fresh water from the slopes of the mountain. The use of this spring was formalised in 1682, with a chamber to protect the Main Spring built in 1813. Over time, the spring water was canalised and, today, it is mostly conveyed underground through a series of pipes and stormwater drains, eventually draining into Table Bay.
The harvesting of this water for irrigation purposes presented a significant opportunity to elevate the role that water played in the history of Cape Town. The Reclaim Camissa project, for example, is working to restore the historical connection between the mountain and the sea, and to develop heritage and tourist resources throughout the CBD linked to the springs and rivers on the slopes of the mountain. In the Khoisan tongue, “Camissa” means ‘the place of sweet waters.’
Arcus Gibb, August 2008. Preliminary Investigation Report – Feasibility Study: the Supply of Irrigation Water to Green Point Common.
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Installation of water-saving devices in stadia
The Cape Town Stadium water supply consists of three incoming domestic mains. A storage tank provides back-up pumped water for the VIP western side. The pitch irrigation water is also drawn from this tank to help facilitate a regular turnover of water.
Roof drainage is achieved through a symphonic drainage system comprising of twelve 160 mm downpipes, concentrated at the north and south ends.
The following water-efficiency measures were included in Cape Town Stadiums design:
- Toilets in the VIP special guest areas are fitted with dual-flush mechanisms.
- All taps have self-closing metering valves and aerators, and low-flow showerheads have been fitted.
- The landscaping design favours water-wise, indigenous plants.
- Rainwater and stormwater harvested off the stadium roof, pitch, podium surface and park is directed to a detention pond.
- A natural soccer pitch with artificial matting was specified to help reduce the need for irrigation.
At the time of the green review (end 2008) the overall saving from the different interventions is estimated to have been 27% below the baseline, which is a significant achievement (Table 12).
Water-saving measures were also included in the upgrade of Athlone and Philippi stadia. Dual-flush was specified for the VIP toilets; taps were fitted with self-closing metering valves, Stadsfontein Spring then and now; and low-flow showerheads were installed.
More info: Water Use and Management: Guidelines for the Hospitality Industry (PDF)
Lessons learnt from water conservation projects
The use of spring water for irrigation results in a significant saving of potable water previously used for this purpose. Efficient irrigation systems will prevent the spring water from being wasted. As a legacy project of the Green Goal programme, the project also created renewed interest in the role that water had played in the development of Cape Town. A project to make the historical spring vaults and infrastructure accessible to the public and tourists is under way.
The initiatives to reduce the amount of potable water used in the new Cape Town Stadium contributed to a significant reduction in the use of potable water. An independent panel of green architects appointed by DEA recognised the applied technologies as best practice in sustainable stadia design.
However, as with the installation of energy-efficient technologies, water-saving devices must be specified in the design stage already, as it is difficult to retrofit some of these to existing buildings.
Key references and source material
- Arcus Gibb, August, 2008. Preliminary Investigation Report – Feasibility Study: the Supply of Irrigation Water to Green Point Common. Reference number R030800196. (Cape Town, South Africa). Commissioned by the City of Cape Town.
- BKS, February 2010. Bulk irrigation design report for the Green Point Stadium and Common. Commissioned by the City of Cape Town.
- Urban Environmental Management Programme and Green by Design WSP, 2008. 2010 FIFA World Cup Green Point Stadium: Environmental Performance Enhanced. (Pretoria, South Africa). Commissioned by Department of Environmental Affairs and Tourism, funded by the Royal Danish Embassy, South Africa.
- WORLDSPORT. July 2010. Host City Cape Town 2010 FIFA Fan Fest™ Green Goal Report.