Taranaki Street Rising Main project nears completion

Wellington Water started construction of the new rising main (a pipe that carries wastewater under pressure) in August 2023. It is a key part of a major upgrade of the city’s wastewater network to ensure a more resilient network and cater for growth. The forecasted cost for completion is $21.4million.  

With the main part of the Taranaki Street rising main now complete and successfully tested, the team at Wellington Water is focusing on putting the rising main into service.  

As most of Wellington’s current wastewater network is comprised of pipes that use gravity to transfer the wastewater, there is a need to use a pump station and rising main to transfer the wastewater to a higher point in the city’s wastewater network. 

The Taranaki Street rising main will be used to send wastewater to the main interceptor tunnel, which carries wastewater to the Moa Point treatment plant. It will be connected to the existing rising main network and help continue service if other mains need to be replaced in the future. If a problem arises in the local network, such as a burst pipe, this system will be able to pick up the load and pump it via an alternative route to the interceptor.

Thanks to use of the latest trenchless technology the project has been delivered with less disruption to the city and the environment than conventional construction techniques. This ‘guided augur bore’ system has enabled the project to be delivered faster, drilling right under sections of Taranaki Street minimising disruption to traffic and reducing the amount of waste to landfill.

Wellington Water Group Manager Network Development and Delivery Susannah Cullen says the team has been working hard to get this work completed and recently pressure tested the pipes to ensure they are ready to go into service, with everything going to plan.

“This key milestone is great testament to the dedication of everyone involved in this project. We are also extremely grateful for residents and businesses in the area for their patience and understanding as these works took place. This is an incredibly important project that’s part of wider work to build the resilience of Wellington city’s wastewater network while also improving environmental outcomes.”

The team has also completed a series of complex ‘shutdowns’ of the existing network in Market Lane. During these shutdowns they have prepared and renewed the pipework to be able to connect the new rising main. 

With some smart thinking, the team onsite managed to get this piece of work done early, shortening the overall duration of the project. This month, work will be done to tidy up Market Lane and put the road back to its original arrangement – a one way street.

Finishing touches

Once connections of pipes near Wigan Street and in Wakefield Street are made to the new rising main, the upgraded network can be brought into service.

On Inglewood Place, work has been done to the pipes that make up the gravity wastewater services that connect to the new pump station. 

Following on from the work in Dixon Street last month, Inglewood Place has been handed back to Wellington City Council to carry out construction of a new toilet block.

With the end in sight for this work in early 2025, the Council appreciates the patience and support from businesses, residents and the public that have been affected by the work.

This is part of Wellington City Council’s whole programme of work to upgrade, renew and reconfigure the pump station and rising main network in central Wellington. This programme involves six projects that will support Wellington city’s growth and improve network resilience.

To keep up to date with the most recent updates, visit the Wellington Water website.