The 120Ha development is immediately south of the future Karnup train station.

Key Considerations

  • Developing Earthworks Concepts / Strategies for entire landholding to maximise development potential.
  • Major servicing strategies to improve project feasibility.
  • Liaison with Service Authorities, Local Government, MRWA and PTA.

Project Challenges


Through previous knowledge of the site and interrogation of the available geotechnical information, JDSi encouraged testing of the areas of the quarry not excavated by previous operations. As a result of further testing and detailed negotiations with the local authority JDSi were able to obtain approval to utilise on site material as limestone quality roadbase material. This provided significant cost savings for the developer and reduced the environmental and safety impacts as a result of the reduction in cartage of road pavement materials to the site.

Liaison with Relevant Authorities

Through constant liaison with the Water Corporation, PTA, MRWA, City of Rockingham and adjacent landowners, JDSi has successfully upgraded a signalised intersection and installed a temporary pressure main along Mandurah Road to specifically avoid vegetation and limit any impact to MRWA infrastructure. JDSi has also had ongoing liaison with PTA as the development immediately adjoins the Perth-Mandurah Rail line. JDSi has established good working relationships with staff at MRWA, PTA and the City of Rockingham.

Servicing Planning and Implementation

JDSi were responsible for the design, approval and contract administration of a Type 40 Waste Water Pump Station (WWPS), including approx 3km of pressure main and 500m of micro-tunneled DN600 gravity main. The WWPS was delivered under Water Corporation’s Developer Constructed Works Process.

Our involvement commenced early in the planning phase as the site was constrained by sewer because of delays to the East Rockingham WWTP. JDSi identified additional capacity in the existing Gordon Road WWTP and through consultation with Water Corporation JDSi successfully completed a concept design report which demonstrated that their Gordon Road WWTP system was able to safely accept out of catchment flows, enabling the lifting of urban deferment for the site earlier than expected

Earthworks Concepts for Different Layouts

As the site is an existing limestone quarry with steep grades across the landform, JDSi were able to modify the design levels to avoid the development being split across 2 sewer catchments. This change allowed the whole development to be serviced by 1 WWPS, thus saving the Developer significant upfront costs as well as saving the Water Corporation the ongoing maintenance and operation costs. In addition, the bulk earthworks strategy was able to realise additional fill material for use on alternative development sites.

Project Description

  • Client:
    Golden Group
  • Start Date:
  • Completion Date:
  • Construction Value:
    $90M (Estimated)
  • Key People
David Hellmuth
David Hellmuth
Project Director
Blair Trew
Blair Trew
Project Manager
Michael Smithers
Michael Smithers
Project Engineer

Project Engineer