Wellington Region Stimulus Funding Renewals for Water and Wastewater

WSP’s innovative and efficient delivery model enables increased speed and reduced carbon emissions, for Wellington’s water and wastewater renewals.

Location

Wellington, New Zealand

Client

Wellington Water

Project Value

$5.7m

Project Status

Completed: June 2020 – July 2021

Key insights:

Wellington Water sought an innovative and efficient delivery model for their ongoing programme of water and wastewater pipe and asset renewals
WSP’s standardised delivery model approach enabled increased use of trenchless technology and reduced carbon emissions
Early collaboration between WSP, Wellington Water, and contractor Capital Water ensured the project ran to time and met the financial and programme requirements around use of stimulus funding.

Key facts

pipe installed

4 km

trenchless installation

80%

Wellington Water’s objective was to trial a more efficient delivery model for their ongoing programme of replacement works for water and wastewater assets, pipes and lateral connections. Their brief also specified that the model should enable and encourage greater use of trenchless technology, and target improvements in areas identified by the Council as having existing and widespread issues. Funded by post-Covid stimulus funding, the programme was also designed in response to local government water services delivery arrangements, and to provide immediate mitigation of community impacts caused by Covid-19.

WSP delivered a successful and efficient programme of water infrastructure projects, with an approach and design team who later rolled out the methodology on subsequent projects. WSP’s deliverables for Wellington Water included working collaboratively with the contractor (Capital Water) and managing the water and wastewater renewals packages in Titahi Bay ($2m) and Karori suburbs ($3.7m). The project successfully met the requirements of the post-Covid stimulus funding, and meant that critical water assets were renewed and maintained.

The Solution

WSP co-developed a framework with Capital Water and Wellington Water to prioritise pipes in the worst condition in areas with minimal constructability challenges. The renewals could be programmed and undertaken with consideration of asset condition and constructability. Assets with high priority but greater construction difficulty were programmed later, to give time for more investigation and stakeholder consultation. Most work involved investigations, including reivew of CCTV footage and physical inspections where possible. WSP initiated meetings with the contractor early in the process, plus walk-throughs with the contractor, consultant and Wellington Water operations personnel.

The Benefits

WSP used a standardised delivery model, process and design for the programme work, which enabled increased use of trenchless technology. Adopting trenchless technology reduces carbon emissions, and the requirement for engineered backfill which has high carbon cost through manufacturing, transport and compaction. Typical pipe sizes ranged from 150mm to 225mm in diameter, and over 4km of pipe length was installed. The pipe installation methodology was predominantly trenchless (80%) with a smaller portion open trenched (20%).