City accepts all findings in independent review on sewer main break

Published on 04 July 2024

City of Gold Coast has reviewed and accepted all recommendations from an independent investigation into the sewer main break in Stapylton which flowed into the Albert River earlier this year.

The investigation by AECOM Australia focused on two key areas - the cause of the break and the delay in detection.

The City continues to work collaboratively with the Department of Environment Science and Innovation (DESI) and specialist consultants to undertake water quality modelling to better understand any environmental impacts with results expected next month.

City of Gold Coast CEO Tim Baker welcomed the AECOM report and said the City commenced implementation of several key recommendations in April following the detection of the leak.

“The City is committed to rigorous and continual improvement across all areas, and we are committed to applying lessons learnt to prevent future incidents,” Mr Baker said.

He said the investigation determined that the break was due to corrosion most likely caused by “aggressive” soil or groundwater, and the omission of a specified wrapping for the pipe at the time of installation (2005) was also a contributing factor.

It also found that condition assessments of the main and a proposed project that would have reduced flows and enabled pipeline renewal had been deferred.

As for the delay in detection, the investigation concluded that several factors contributed to the break remaining undetected.

These included:

  • The City’s dependence on breaks being reported by members of the public, a measure which is ineffective for isolated mains.
  • Higher than average flows in the Albert and Logan River, which reduced the potential for river users to notice the spill.
  • The flow meter at the Beenleigh Sewage Treatment Plant was not alarmed or monitored regularly by the City.
  • No advice was received from Logan City Council about reduced inflows over the period of the spill.

It did find that once detected, the repair was completed in “good time”.

There are several recommendations which broadly, include:

  • reviewing our asset management strategy and undertaking planning for critical sewage rising mains.
  • growing the size of our asset management team.
  • improving technology and instrumentation to detect flows and breaks.
  • reviewing the condition of pipes installed in the same period.
  • revising our arrangement with Logan City Council.

“Much of this work is already underway including the development of a four-year critical sewerage pressure main plan, targeted condition assessments of all high-risk mains and reviewing of the specific piping installed during that period.”

Mr Baker said that the root causes of the incident were related to processes and structures that were no longer in place or already under review.

“We are a City that has undergone incredible transformation in the last few years. This included restructuring our water business and doubling our investment in asset renewal.

“We can assure the community that we have taken this incident very seriously and due to our new structure and operating model we were able to quickly address the issues.”

The full report including recommendations and the work already undertaken by the City is can be found here.

Mr Baker said the City continued to cooperate with the Department of Environment, Science and Innovation’s (DESI) investigation into the incident.