Backflow devices and dams

Backflow devices reduce the chance of backflow flooding by preventing water flowing back up stormwater drainage paths and are one of the many ways Council helps to manage flooding in Brisbane. 

A variety of backflow devices have been installed across the city, each designed for the local drainage requirements. Some backflow devices self-close depending on hydraulic conditions. Council follows strict operating procedures to ensure the safe operation of these devices. Even though backflow devices have been installed, flooding may still occur from other flood sources. It is important to still prepare your home and family for flooding. 

How backflow devices work


No backflow device: water from the flooded river backs up through stormwater drains and floods streets and/or properties
Backflow device in place: water from the flooded river does not back up through stormwater drains
Potential flooding scenario: streets and/or properties could still flood from localised rainfall and water from flooded river escaping through the banks or overtopping

Council has installed 66 backflow devices at 16 locations along the Brisbane River to help protect areas from backwater flooding. These river-based devices supplement existing devices located on Brisbane's creeks and coastal foreshore. These devices are part of a suite of tools Council employs to provide flood resilience to the community. Ongoing operational testing is untaken at low tide and king tide.

Stormwater drainage outlet on the Brisbane River

Future backflow device works will be considered in Council’s future drainage program, which is subject to Council’s annual budget and citywide priorities.

Backflow device locations

The map on this page shows the approximate location of Brisbane River backflow devices. These devices are located within the drainage network. Council strongly discourages residents from entering the drainage network or waterways.

Download a map of backflow device locations in Brisbane (Word - 1.2Mb).

To report an issue with a backflow device, contact Council.

Dams and referable dams

Dams are important infrastructure used for water storage and flood mitigation. Dams are designed to mitigate flooding by temporarily detaining water during storm events and releasing that water in a controlled way to reduce downstream flooding. As the dam fills up and water reaches a set level it releases water. This is commonly referred to as a dam spill. All dams in the Brisbane Local Government Area are ungated, which means the water is not controlled through the operation of gates. These dams are designed to spill when the water level gets too high.

In some circumstances a dam spill may result in downstream flooding, which may cause localised flooding and localised road closures.

Some dams are deemed ‘referable dams’ under Queensland Government legislation. This is determined by an assessment that shows there is the potential risk of two or more people being impacted by downstream flooding due to dam failure.

In extreme circumstances dams can also release water in an uncontrolled way. For referable dams, where downstream hazards for uncontrolled releases are significant, this process is managed through an Emergency Action Plan (EAP). Emergency Action Plans are managed through the dam owner.

Brisbane City Council owns the following referable dams.

  • Forest Lake Dam, Forest Lake.
  • Gordon Road Detention Basin, Bardon.
Forest Lake referable dam

The following four referable dams in Brisbane are owned by Seqwater:

  • Enoggera Dam, The Gap
  • Gold Creek Dam, Brookfield
  • Lake Manchester Dam, Lake Manchester
  • Leslie Harrison Dam, Capalaba. This dam is located between Brisbane and the Redland City Council local government areas.

There are three referable dams located outside of the Brisbane local government area that are owned by Seqwater where spills may impact parts of the Brisbane local government area:

  • North Pine Dam, Strathpine
  • Somerset Dam, Kilcoy
  • Wivenhoe Dam, Fernvale.

Council encourages residents to sign up to the free Brisbane Severe Weather Alert service. 

Seqwater has a free opt-in Dam Release Notification Service

Last updated: 8 September 2022

Brisbane City Council acknowledges this Country and its Traditional Custodians. We pay our respects to the Elders, those who have passed into the dreaming; those here today; those of tomorrow.