Backflow

The suburbs and surrounding areas of Brisbane have been built on a low lying flood plain vulnerable to water inundation. Storms, heavy seasonal rain and flooding are a natural part of living in Brisbane and Brisbane City Council is committed to reducing the risk of flooding in our city.

During the January 2011 flood, some parts of Brisbane were affected by water which came up from the river through the drainage networks and into our streets. This is referred to as backflow flooding.

Between July 2011 and May 2012, Council conducted technical investigations to look at the feasibility of installing backflow devices in areas where backflow flooding occurred. The investigation was required as these devices are not suitable in all situations.

A backflow device is designed so that water flows in one direction through piped stormwater systems and minimises water flowing back up stormwater pipes. Backflow devices are effective at preventing stormwater flooding in certain circumstances, but there is no guarantee of full flooding protection. While these devices reduce the chance of backflow flooding, they cannot prevent other forms of flooding.

Backflow devices are one of many flood mitigation tools and strategies that Council is considering to help protect Brisbane from the impacts of flooding. The wider flood risk management strategy also considers the role of planning measures to assist in managing all flooding risks in Brisbane.

Investigations into backflow

The investigation into the feasibility of backflow devices along the length of the Brisbane River is now complete.

The technical investigations were carried out in two stages:

• Stage 1 - Pre-feasibility Investigation
  • pre-feasibility investigation for implementation of backflow prevention technology in the three case study areas of the CBD, Rosalie/Milton and New Farm
  • a city-wide desktop review of other affected areas along the Brisbane River
• Stage 2 - Technical Investigation
  • developing detailed designs for the implementation of backflow devices in the three case study areas of the CBD, Rosalie/Milton and New Farm. Construction has been completed at New Farm and is underway in Milton and the CBD
  • investigations along the length of the Brisbane River to determine stormwater systems that contributed to backflow flooding in the January 2011 floods and that could be retrofitted with backflow devices

Installation of backflow devices

The installation of three backflow devices in the Moray Street drainage system in New Farm have been completed. Works have commenced to install four backflow devices in the Cribb Street drainage system in Milton. The Cribb Street drainage system services parts of Cribb Street, Crombie Street, Walsh Street, Manning Street, Railway Terrace, Park Road and McDougall Street.

Work has also commenced to install backflow devices in the Brisbane CBD. Devices are currently being installed in Margaret Street, Alice Street and Charlotte Street stormwater systems.

11 further stormwater systems have been identified as high priority sites for backflow device installation and will receive funding over the next four years.  These sites are:

• Castlemaine Street, Milton
• Creek Street, Brisbane
• Leybourne Street, Chelmer
• Lang Parade, Rosalie
• Queenscroft Street, Chelmer
• James and Sydney Streets, New Farm
• Ryan Street, West End
• Harrison, Johnston, Tennyson Street, Bulimba
• Coronation Drive, Auchenflower
• Vivian Street, Tennyson
• Gailey Road, St Lucia

These 11 projects will provide benefit to 80% of properties that were impacted by flooding in January 2011.

Other feasible systems will be considered in Council’s future drainage program.

Consultant reports

Download the consultant reports Stage 1:

• MWA Backflow Report Volume 1 - Executive Summary (PDF - 3.1Mb)
• MWA Backflow Report Volume 1 - Part 2 (PDF - 1Mb)
• MWA Backflow Report Volume 1 - Part 3 (PDF - 2Mb)
• MWA Backflow Report Volume 1 - Part 4 (PDF - 1.5Mb)
• MWA Backflow Report Volume 1 - Part 5 (PDF - 2.8Mb)
• MWA Backflow Report Volume 1 - Part 6 (PDF - 1.7Mb)
• MWA Backflow Report Volume 1 - Part 7 (PDF - 4.1Mb)
• MWA Backflow Report Volume 1 - Part 8 (PDF - 1Mb)
   

• MWA Backflow Report Volume 2 - Attachments Part 1 (PDF - 1.4Mb)
• MWA Backflow Report Volume 2 - Attachments Part 2 (PDF - 1Mb)
• MWA Backflow Report Volume 2 - Attachments Part 3 (PDF - 5Mb)
• MWA Backflow Report Volume 2 - Attachments Part 4 (PDF - 580kb)
• MWA Backflow Report Volume 2 - Attachments Part 5 (PDF - 920kb)
  

Download the consultant reports Stage 2:

• Backflow Report Executive Summary - Part 1 (PDF - 679kb)
• Backflow Report Executive Summary - Part 2 (PDF - 2.7Mb)
• Backflow Report Executive Summary - Part 3 (PDF - 2.3Mb)
• Backflow Report Executive Summary - Part 4 (PDF - 2Mb)
• Backflow Report Executive Summary - Part 5 (PDF - 1Mb)
• Backflow Report Executive Summary - Part 6 (PDF - 2.3Mb) 
   

• Backflow Investigation Report - Stage 2 - Part 1 (PDF - 939kb)
• Backflow Investigation Report - Stage 2 - Part 2 (PDF - 1.5Mb)
• Backflow Investigation Report - Stage 2 - Part 3 (PDF - 2.4Mb)
• Backflow Investigation Report - Stage 2 - Part 4 (PDF - 1.7Mb)
• Backflow Investigation Report - Stage 2 - Part 5 (PDF - 2.4Mb)
• Backflow Investigation Report - Stage 2 - Part 6 (PDF - 1.5Mb)
   

• Case Study Areas - Part 1 (PDF - 770kb)
• Case Study Areas - Part 2 (PDF - 385kb)
• Case Study Areas - Part 3 (PDF - 2.9Mb)
• Case Study Areas - Part 4 (PDF - 1.4Mb)
• Case Study Areas - Part 5 (PDF - 275kb)
• Case Study Areas - Part 6 (PDF - 1.4Mb)
• Case Study Areas - Part 7 (PDF - 557kb)

Summary Report

Download the Backflow Investigation Report Summary (PDF - 24Mb)

More information

For more information, you can:

• download the Backflow Fact Sheet June 2012 (PDF - 708kb)
• phone the Backflow Project Team during business hours on 1800 884 681
• phone Council on 07 3403 8888
• email the Backflow Project Team
• write to:
  Backflow Project
  City Projects Office
  Brisbane City Council
  GPO Box 1434
  Brisbane Qld 4001