Power and Water is upgrading sewerage infrastructure in the Rapid Creek Reserve. The upgrade will reduce the risk of sewage  overflows caused by stormwater entering the sewerage network during active wet seasons.

The suburbs of Rapid Creek, Millner and Alawa are serviced by two sewerage pump stations that are connected by a gravity sewerage main:

  • Rapid Creek Pump Station, located on Rapid Creek Road,Rapid Creek.
  • Lakeside Pump Station, located on Lakeside Drive, Alawa.
The issues

The sewerage network in the Rapid Creek/Millner catchment area is lower than that of the Alawa catchment area.

During heavy rainfall, high levels of stormwater enter the sewerage network, causing a crossflow from the Lakeside sewerage system into the lower lying Rapid Creek system. This can cause sewage overflows in the lower lying areas of Millner through access chambers and property overflow relief gullies.

The works

Works started on Monday 13 May 2019 and took approximately six weeks to complete.

The worksite is on Crown Land, managed by Parks and Wildlife. It is in an intertidal zone adjacent to Rapid Creek, in the mangroves and the stormwater run-off area.

The gravity sewerage main is being modified to allow the pump stations to be isolated and prevent crossflow between the two systems, but will still allow the connection of the two pump stations for operational and maintenance purposes when needed.

To access the site, the existing access track will be upgraded, some vegetation regrowth cleared and two existing concrete pits replaced with two larger pits and interconnecting pipework.

The site will be backfilled and the area around the pits built up to provide a level work area that will allow safe all-weather access to the sewerage infrastructure.

These works are not related to the flood mitigation works undertaken by the Department of Infrastructure, Planning and Logistics in the upstream area of Rapid Creek near Marrara. However, both projects are designed to improve wet season outcomes for Millner and Rapid Creek residents.

Stormwater and the sewerage system

The sewerage and stormwater drainage systems are two separate networks.

Around homes, stormwater may enter the sewerage system through broken sewer pipes, house downpipes and pool backwash being drained into the overflow relief gully and run-off from back yards being drained directly into the system through unauthorised connections.

Property owners have a responsibility to ensure their private infrastructure is approved, maintained, and run-off not directed to the overflow relief gully.

Power and Water is working to minimise the amount of stormwater entering the sewerage system by:

  • installing flow gauges in the sewerage catchment areas to gather data and information to identify where the issue is the worst.
  • inspecting properties to check sewerage connections.
  • encouraging property owners to check and rehabilitate their property infrastructure if an issue is identified.
  • educating residents about the issue, solutions and their responsibilities.
  • upgrading sewerage infrastructure to better service the community.