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Western Adelaide Wastewater Network Upgrade
Critical sewer upgrades were delivered with minimal impact on commuters and the environment

Background

As a result of urban development and predicted residential growth in the Adelaide CBD and the south-eastern suburbs, upgrades were required to the Western Adelaide Wastewater Network.

The existing trunk sewer main runs along West Tce, through the Adelaide Cetntral railways station rail yard and over the River Torrens. It was over capacity, leading to surcharge of the network and odours. The objective of the project was to reduce wastewater flow and resulting odour in this water main, as well as providing additional flexibility in the wastewater network to cater for future needs.

Scope

The Project required the installation of approximately 2.5 kilometres of new gravity sewer pipework across the following locations:

  • West Terrace, Adelaide(adjacent to intersection with Glover Avenue)
  • Narnungga (Park 25)
  • Belair and Seaford rail lines crossing between Park 25 and the old SA Water/EWS Depot
  • The old SA Water/EWS Depot (corner of Port Road and James Congdon Drive)
  • Port Road Crossing from the old SA Water/EWS Depot to Bonython Park
  • Tulya Wardli / Bonython Park, Parklands, Adelaide
  • River Torrens crossing from the Southern Bank to the Northern Bank in Bonython Park (Tulya Wardli), North Adelaide
  • Torrens Junction rail crossing from Bonython Park North Adelaide to the North Adelaide Par 3 Golf Course in Pirltawardli (Park 1)
  • War Memorial Drive crossing from the Par 3 Golf Course to the North Adelaide Golf Course.

There are 30 manholes on the pipe alignment that are constructed from GRP pipe risers, concrete cover slabs and standard sewer lids.

Bypass pumping was required at the upstream connection to account for a daily peak flow of 320 L/s.

Outcomes

This project has showcased new approaches to working with live oviform mains, isolate and bypass pump deep, high flowing mains, all without impacting the catching network and commuters on highly trafficked roads.

  • The development of new siphon chambers consisting of three mains to take the ADWF, PWWF and ventilation through the siphon infrastructure, will be a guide for future SA Water projects when implementing a similar system.
  • The innovative prefabricated GRP manholes allowed for more rapid installation and improved safety by not having extended works within deep chambers as is typical with traditional concrete chambers. This method has already been adopted by the client for other projects and the concept can be adapted to other industries and processes.
  • Access and egress to the chambers for maintenance and operational staff was carefully thoughts through with stakeholders addressing all previous risks and issues previously outdated siphon chambers were experiencing.
  • The planning and scheduling of works in highly built up parts of the CBD that receive significant amounts of wastewater flows required a well planned and executed bypass pumping arrangement. Pushing the design envelopes for the bypass pumping pipework allowed for a significantly reduced pipework (laid above ground) footprint.

The project has achieved a very good result from an environmental perspective, minimising impacts on the River Torrens and its ecosystem, decreasing potential overflows and avoiding damage to important trees in the parklands. Diversion of sewer flows from the existing sewer in West Tce also avoided areas of cultural significance surrounding the railway corridor and the River Torrens north of the new Royal Adelaide Hospital.

Related Projects

Project South East Flows Restoration Project $50m South Eastern SA Project Glenelg to Adelaide Parklands (GAP) Recycled Water Project $75m Adelaide, SA