• Client: Defence Housing Authority
  • Value: $13.8M
  • Completion date: July 2014


This has been one of the more complex subdivision projects that we have undertaken in recent years. As well as being on the site of a very steep slope, which was heavily affected with even a small amount of rain, there were also a number of large service relocations/removals that had to take place. These included the following:

  • TransACT Optic Fibre relocation
  • 300mm watermain relocation (this main ran through the middle of the site and no other hydraulic works could be undertaken until the relocation of this main had taken place)
  • 450m watermain relocation
  • Working around and underneath existing 750mm watermain
  • Relocation of existing overhead HV network incorporated into the subdivision common trench works
  • 4ML underground stormwater storage tank and pumping system.

There were also major concrete structures to be constructed as bio-retention ponds (exposed faces had to be faced with rock). These structures had a number of compartments separated by weir walls as well as elevated, cantilevered walkways and layered medium construction. They had to be built adjacent to existing schools operating in the area and careful liaison and management of water runoff was required to ensure that schools were not disrupted.

In order to assist the DHA in their programme of house construction (new defence personnel had to move into houses early in 2015), we negotiated and assisted the builder’s in being able to commence their work prior to Operational Acceptance. This was done as a gesture of goodwill and resulted in quite a complex handover process.