Rapid global urbanisation means governments are reassessing how to meet increased urban densities while creating vibrant, healthy and sustainable environments. The provision of basic services to South Africa’s citizens is a key focus of our government. One such area in dire need of service delivery is the Ekurhuleni Metropolitan Municipality’s Palm Ridge Extension 9. Recent plans to deliver water and sanitation services to thousands of township residents have required expert coordination and engineering from a dedicated team of professionals. IMIESA takes a look at this project.

Housing project receives water and sanitation

Located to the south of the existing Palm Ridge extensions 1 – 8 and to the north of Kliprivier Drive (R550), many of Palm Ridge Extension 9’s citizens were without bulk and internal water, sanitation, roads and stormwater. Global engineering, management and specialist technical services group Aurecon was appointed by Ekurhuleni Metropolitan Municipality (EMM) as design engineers to undertake the preliminary, detail design, contract documentation and site supervision.

Scope of works
Following compilation of a master plan for the area, compiled by GLS (Pty) Ltd – master plan consultants to the EMM – planning for three connections to the development from the proposed bulk water supply pipelines commenced, including:

• A connection from a new 600mm diameter pipeline to be located to the north-west of the development connecting Palm Ridge Extension 9 to the existing Eden Park Reservoir.
• A connection from a proposed new 35Mℓ Palm Ridge reservoirvia a new 600mm diameter pipeline, which traverses through the existing Palm Ridge township extensions, and which will feed the south-eastern portion of the development.
• A 250mm diameter pipeline from the existing Palm Ridge Township reticulation lines to feed the central portion of the development interlinking with the later 600mm diameter pipeline.

In addition to the bulk infrastructure listed above, a new pumpstation and a new pipeline from the existing Rand Water pipelines to the existing Palm Ridge Reservoir will also be required.

Furthermore, the project included the design of all internal water and sewerage, which ultimately will service approximately 6,500 stands, and a bulk outfall sewer.

Overcoming project challenges
“Although this sounds relatively straight-forward, they are everything but,” comments Aurecon technical director Chester Kan. He goes on to say that“In order to ensure that the roll-out of the infrastructure proceeded smoothly and can be closely monitored over such a vast area, Aurecon’s construction design followed a phased approach, to service these different phases.”

“A further project complication includes that Palm Ridge Extension 9 is adjacent to a wetland. Working together with town planners Urban Dynamics, Aurecon managed detailed geotechnical and environmental studies, and following the outcomes of these, had to amend its engineering and construction designs to ensure absolute sustainability and minimise any impact on the wetland. This also meant that water use licenses have had to be obtained” he adds.

Forward thinking
Because populations are always expanding, placing even further strain on infrastructure, the proposed bulk water infrastructure has made provisions for thesupply of the proposed Reitspruit and Waterval developments, as part of Palm Ridge Extension 9. In addition, theGLS masterplanproposal has made provisions for the shortfall of the existing bulk infrastructure in the Palm Ridge Township as a whole.

“Toilet tops have also been included in our planning to ensure that when the time comes for formal houses to be constructed in the area, the current informal dwellings can be removed, with the infrastructure for toilets already in place,” adds Kan.

Ensuring the strictest standards are met
“The design of all of the bulk and sewer reticulation has beendone according to the Guidelines forHuman Settlement Planning and Design issued by the CSIR and the design standards and specifications approved by the EMM’s infrastructure services department,” says Kan. Coupled to this, the internal water and sewer reticulation was designed by a computer assisted civil designer programme to ensure the acute accuracy of all design details.

Reservoir construction
In addition to preliminary and detail design of the infrastructure referenced, Aurecon was also requested to provide a proposal for the construction of a new 35Mℓ reservoir for the infrastructural upgrade and extension of Palm Ridge. “The proposed reservoir is a circular post-tensioned concrete reservoir of 60m diameter with a water depth of 12.5m. The reservoir walls will be constructed of post-tensioned concrete varying in thickness from 600mm at the base to 400mm thick at the top of the wall, while the reservoir floor will be constructed on a 175mm thick slab with under floor drainage for leak detection. Water tightness of the reservoir will be ensured by the use of water bars in all construction joints,” explains Aurecon engineer Geoff Green. To ensure that the geotechnical conditions are favourable for the construction of the reservoir, a detailed geotechnical investigation was undertaken.

“Although completion of the project will take several more months,” says Kan “The project has already served to unite the community in terms of a common goal of adequate service delivery. It is being funded by EMM and all representatives of the community, including ward councilors,arebeing extensively consulted to ensure that the project implementation meets with the consent of the community while at the same time complying with sound and innovative engineering principles.”