New stormwater drain for Joynton Avenue - review of environmental factors

This proposal will reduce the risk of flooding in the area.

Project Status: Closed

Public consultation period to

What we’re doing

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 all relevant assessment requirements are satisfied and a public exhibition of the review of environmental factors report takes place. We expect to finish the drain by 2020.

A map of the stormwater route
Map of proposed route

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.
  • We 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.

A diagram showing micro tunnelling and how it works

How you can give feedback

Give your feedback by completing an online form.

Online form

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.