Wellington City Council Overflow Tank
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Client: Wellington City Council
Sector: Foundations
Location: Wellington
Contract Value: NZ $1.7 million
Completed: Sep 2004
Main Contractor: Brian Perry Civil


In order for the Wellington City Council to comply with a consent condition that sewage overflows not discharge to the stormwater system from 1 July 2004, it was necessary that a sewage storage tank be constructed.

The work scope included:

  • Construction of a reinforced concrete underground storage tank 30m long x 12m wide x 5.5m deep.
  • Provision of temporary sheetpile cofferdam.
  • Installation of inlet and outlet pipes with connections to the existing sewerage system.
  • Installation of pumps and the associated controls, telemetry and electrical works.
  • Reinstatement of a carpark, traffic islands and adjacent garden areas.

The work site was located in the central CBD and required a high standard of traffic management in a large volume traffic area.