New stormwater drain for Joynton Avenue – review of environmental factors

New stormwater drain for Joynton Avenue – review of environmental factors


The review of environmental factors has been approved. Thanks to everyone who provided feedback. Planning is underway to start construction works in 2020.

We are seeking your feedback on a proposal to build a new stormwater drain on Joynton Avenue between O’Dea Avenue and Elizabeth Street, Zetland. This will reduce the risk of flooding in the area.

Green Square was once a network of swamps, wetlands and creeks. Hazardous flooding has been a constant challenge in the area, with floodwaters reaching 2.3 metres in Joynton Avenue during storms in April 2015.

The new drain will carry stormwater from the southern part of Waterloo and surrounding areas along Joynton Avenue to the Green Square stormwater drain.

We will finalise the design and start construction from 2019, once the City has satisfied all relevant assessment requirements and undertaken a public exhibition of the review of environmental factors report. We expect to finish the drain by 2020.

Map of proposed route

Map illustrating proposed stormwater drain pipe on Joynton Avenue between O’Dea Avenue and south of Elizabeth Street. The microtunnelling shafts and stormwater connection points will act as reception pits for the placement of pipes. These pipes will connect under the western footpath of Joynton Avenue, and the eastern footpath near the intersection with Tilford Street.


What is a review of environmental factors?

A review of environmental factors is a planning assessment report used by councils to assess the main engineering, environmental and planning issues associated with projects developed for public use.

The report documents possible impacts the project will have on the environment and details steps to be carried out to avoid, minimise or mitigate those impacts.

Areas assessed by the report

  • engineering, environmental and planning factors
  • tunnel and pit designs and operating requirements  
  • construction impacts and risk mitigation strategies
  • impacts on flora and fauna
  • law requirements and approvals.

Report summary

  • Microtunnelling with a tunnel boring machine is the preferred construction method.
  • The City of Sydney will review all construction and environmental management plans before construction starts.
  • The construction contractor will be required to document the plans and manage environmental impacts such as noise, traffic, vibration, contamination, dust, erosion, sediment, water quality, flooding, trees and waste. 
  • Areas disturbed by microtunnelling launch and retrieval pits will be restored to pre-construction condition as closely as possible.
  • If the tunnel boring machine becomes stuck underground, open excavation may be required to retrieve the machine. An arborist will provide management actions to avoid and mitigate impacts to trees should excavation be required to retrieve the tunnel boring machine.
  • Extensive geotechnical investigations have been carried out to better understand ground conditions and minimise tunnel boring risks.

About microtunnelling

Microtunnelling minimises noise, dust and disruptions to traffic. It also means we can retain the fig trees on Joynton Avenue.

It involves using a tunnel boring machine to install pipes underground through a launch pit. We looked at a range of options and because this technique minimises the need for open trenching, it reduces environmental impacts for people living, working and commuting in the area.

The tunnel boring machine digs an underground path, into which we install concrete pipes. We will dig pits at each end of the path to launch or retrieve the machines. The size and location of the launch and retrieval pits will be confirmed in the detailed design.

Illustration of microtunnelling process which will take place along Joynton Avenue, under the footpath on the western side between O’Dea Avenue and Elizabeth Street. There will be a series of large reception pits which will be linked by the stormwater drain pipes. Pieces of pipe will be lowered into the pits and placed in the tunnels to link the whole length of the stormwater drain.Microtunnelling diagram shows launch and retrieval pits. 


How you can give feedback

You can view the plans and give your feedback by completing our feedback form.

Feedback form

Your feedback will help us determine the final design for the drain.

Consultation closes at 5pm on Monday 19 November 2018.

Feedback may be published in publicly available reports at the end of the consultation period. Your name or organisation's name may appear in these reports with your feedback attributed. If you would like your feedback to be kept confidential, please let us know when making your submission.

Other ways to give your feedback

We want to make sure everybody has the opportunity to provide ideas and feedback.

If you prefer to talk to us in person, please contact the City of Sydney officer listed in contacts.

If you are Deaf or have a hearing or speech impairment you can contact us through the National Relay Service. You will need to provide our phone number 02 9265 9333.

If you need an interpreter you can contact us through the Translating and Interpreting Service  on 131 450. You will need to provide our phone number 02 9265 9333.


Key dates

Public consultation period
22 October to 19 November 2018 


Kristina Zarich
Green Square Community Relations
1800 305 005

Nava Jeyachandran
Senior Project Manager
02 9265 9333

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Last updated: Thursday, 28 February 2019