Botany Area Servicing Strategy, Sydney Water Corporation

The overall aim of the Botany Area Plan Project was to prepare an integrated strategy for the provision and management of water, wastewater, recycled water and stormwater infrastructure in order to provide safe, reliable and sustainable water services.

These services will meet the needs of urban growth in the Botany area, while complying with the requirements of Sydney Water Corporation’s (SWC) Operating and Environmental Projection Licences (EPL).

The Botany area is an area close to the Sydney CBD, which is in the midst of plans for major redevelopment (some have already been initiated). The Botany area includes the in-fill growth areas (those covered within this area plan) of Redfern/Waterloo, Green Square, Wolli Creek, Cooks Cove and Sydney Airport. The plan boundary also incorporates the areas of Alexandria/Mascot, Botany Banksmeadow and North Arncliffe as they include minor growth pockets that are not the focus of this area plan, but have been considered.

The outcomes of the servicing strategy were discussed in terms of SWC’s Corporate Sustainability Goals, which provided the framework to fully address the economic, social and environmental aspect of SWC’s sustainability performance. These goals were:

  • To provide clean safe drinking water
  • To contribute to clean beaches, oceans, rivers and harbours
  • To help develop a water efficient city
  • To provide effective customer service
  • To optimise resource use
  • To deliver an economically efficient and viable business

The first step in the process was to agree upon a set of objectives for the strategy with the input from a number of key high-level stakeholders. This enabled derivation of a set of 15 criteria that potential servicing initiatives could be qualitatively and quantitatively measured against.

Demands in each of the growth areas were calculated by performing research into the future populations (residential and commercial) and the volume of water that was likely to be used for each end-use that could be potentially replaced by non-potable water. These non-potable water demand figures then allowed the determination of a broad set of non-potable water servicing initiatives that would be able to meet those demands.

From the set of non-potable water servicing initiatives a long-list of options was devised, each consisting of a water type, a water source and a treatment/distribution scale and method.

A detailed assessment was then performed on each short-listed option. This involved investigation into potential social, environmental, planning, technical demands, (water balance using GHD's Toolkit, hydraulics, required infrastructure amplification and/or upgrading) and financial constraints and risks.

These qualitative and quantitative inputs were then utilised to perform a multi-criteria analysis to determine the preferred option. Weighting of the criteria was first performed to determine their relative importance against the other criteria and then scoring of qualitative criteria was performed. This process was performed internally (within SWC) and externally (with a range of key stakeholders). The Liverpool-Ashfield pipeline (LAP) network was the preferred option for both groups.

The LAP network option involved the transfer of secondary treated effluent from the LAP to a recycled water treatment plant (to be potentially located at Potts Hill). The tertiary treated water will be stored in a buffer tank and then distributed to all future growth via new recycled water trunk mains or reusable disused gas mains to meet the non-potable demands.

A further detailed investigation was performed on the LAP network to determine specific risks, costs and requirements (planning and infrastructure and/or upgrade) and to develop a preliminary investment and implementation plan.