This is an upgrade project being carried out by Wellington Water – the immediate impact will be disruption of traffic along Seaview Road so please allow for that in your travels.
The information below is from the project page, so check that page out for more information and project profgress and updates.
What we’re doing
As part of our work to improve our wastewater resilience, we are duplicating a section of pipe from Barber Grove, down the middle of Randwick Road, to the Seaview Wastewater Treatment Plant.
The existing concrete pipeline transports wastewater from 90 percent of Hutt Valley residents, is over 50 years old and highly vulnerable to earthquakes.
• installing a new 1.2km long by 1m wide
• installing 55% of the pipe using a micro tunnelling method. This involves using innovative infrastructure technology called a Micro Tunnel Boring Machine (MTBM), which means no digging trenches. We’ll share more on this technology later on, once in use later in 2022.
This project is a critical addition towards strengthening our core infrastructure and protecting our waterways. With pipes like these nearing the end of their useful lives, coupled with the growth we’ve been experiencing, our infrastructure is under pressure and it’s crucial we invest before a significant event such as an earthquake. This project builds resilience into our network, and ultimately protects our environment from wastewater overflows now and into the future reducing the risk of wastewater entering our environment in a major earthquake.
Due to the difficult ground conditions and high traffic volumes, businesses and the community, multiple construction options were considered during the design phase.
The proposed method for the pipeline installation is using a Tunnel Boring Machine (TBM) from Barber Grove to the Randwick Road / Seaview roundabout. This would involve intermittent excavations along Randwick Road (approx. 200m apart) with the final excavation at the roundabout. At the roundabout, existing pipe sleeves will be used to cross both the Awamutu and Waiwhetu Streams to bring the pipe onto Seaview Road.
Accessing these sleeves will involve excavation on both stream banks. Open trenching would then connect to the Seaview WWTP. Excavation depths across the pipeline range from 2.5 – 9m deep.