Major Stormwater & Wastewater Upgrades

McConnell Dowell New Zealand is working in collaboration with the Hutt City Council on upgrades to their three waters network. Together, we will deliver a low-impact, low-risk construction method for its major new stormwater and wastewater upgrade project in Lower Hutt.

The project will improve resilience and capacity in the network by installing new pipelines, pump stations and storage tanks in the busy city centre. Funding has been provided by Hutt City Council (HCC) and National Infrastructure Funding and Finance (NIFF), through the Infrastructure Acceleration Fund (IAF). When complete, these upgrades will enable the construction of up to  3,500 new homes across the Hutt Valley. 

Since mid-2025, we have reviewed the preferred option for constructability, operational safety and prepared a preliminary design ready for resource consent. This year, we will support engagement with the local community, iwi, and other stakeholders to complete the consenting process and a plan for construction. 

Last year, we worked with designers Holmes Consulting and Delve Underground to help develop the preferred pipeline alignment and construction method, drawing on our trenchless tunnelling expertise.

Detailed design will commence later this year, with construction likely to start in early 2027, once consent for the project has been granted. 

Key challenges for the project include integration of the pump stations within the urban landscape, working with Riverlink Alliance to reduce traffic delays caused by construction, and minimising impact on the aquifer that supplies the Hutt’s drinking water.

Micro-tunnelling within the road corridor is an ideal way to avoid the above-ground risks and minimise traffic disruption. We will use our trademark creative engineering to work above the aquifer, which is in different strata underground.

The project scope includes:

Wastewater network upgrade:

• new gravity pipes to divert peak flows and increase capacity
• an offline pump station and temporary storage facility
• odour control
• a new rising main from the pump station, across the new Melling River Bridge, to the western side of the river
• a new gravity main that connects with the existing Western Hills Main Sewer.

Stormwater network upgrade:

• a weir chamber inlet and gravity pipeline
• a storage tank on the eastern side of the Te Awa Kairangi / Hutt River
• a rising main, a pump station and a gravity interceptor
• a new outlet structure in the riverbank.

Find out more about the project and sign up for updates at Hutt City Council’s website: https://www.huttcity.govt.nz/council/our-projects/infrastructure-acceleration-fund-iaf

Below are the proposed route alignments for the new stormwater and wastewater pipelines.