Yarrabilba Wet Weather Storage Tank

About the project

The project involved the construction of a 2ML wet weather, concrete storage tank and associated inlet and outlet pipework. The tank formwork was constructed and poured, the internal walls where then Polyurea sealed. On completion the entire tank was completely buried underground. The stormwater harvesting tank is an essential part of the reticulation network for this fast growing community. The storage tank forms part of a number of electrical and water packages delivered at the Yarrabilba site for Lendlease by Pensar.


Yarrabilba, Queensland

Client & Duration

Lendlease Communities
January 2014 - August 2014

Project Scope

  • Excavation and material stockpiling to establish 30m diameter x 4m deep site for the tank
  • Construction of concrete and reinforced steel tank and sealing of all internal surfaces with polyurea
  • Installation of DN375 inlet and outlet pipework including live connection into sewer pump station
  • Installation of final fixtures, access ladders, access hatches, and level probes
  • Hydrostatic testing of the tank in accordance with AS3735 – ‘Concrete structures retaining liquids’


  • Majority of the work was undertaken at heights and in confined spaces
  • Multiple rain events, including Cyclone Debbie, occurred during construction
  • Despite proactive actions to protect the site, Cyclone Debbie caused some site and material damage that required remediation and cleaning
  • Due to a new road adjacent to the site, access and storage was more restricted


  • The project was completed with zero lost time injury incidents, despite the hazardous environment
  • As a result of exceptional safety outcomes, Project Manager, Laura Arias, received a ‘Recognition in Safety Excellence’ award from the client
  • The impacts of Cyclone Debbie were significantly reduced through proactive planning and mitigation
  • The project was successfully completed within schedule and cost constraints, despite being impacted by the cyclone
  • Zero defects were identified during post-project inspections

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