Read the full, joint press release from One Mahurangi and Watercare that was published late yesterday:

12/12/2024:

We confirm a solution for Warkworth pipeline that minimises disruption to community

We have confirmed a solution for the planned growth pipeline through Warkworth’s town centre that keeps disruption to the community to a minimum, and has the support of local business association One Mahurangi.

Our Board of Directors today accepted a recommendation from management to move forward with its preferred route using mostly microtunnelling technology. Two short sections will still need to be open-trenched.

Our chief strategy and planning officer Priyan Perera is happy to share the news with the community.

“We’re really pleased to have closely collaborated with stakeholders to identify a route and construction methodology that keeps disruption to the community – particularly to local businesses – to a minimum. This has always been a priority for us.

“This pipeline is an incredibly important piece of infrastructure that not only supports new housing north of the Mahurangi River, but will also significantly reduce the number of overflows to the river that occur in wet weather.”

Our staff have worked closely with mana whenua Ngāti Manuhiri, local politicians and business association One Mahurangi to explore all of the available options over the past few years.

“Local business owners had expressed serious concern over the potential impact a fully open-trenched pipeline could have on their shops and services. We listened to their viewpoints and worked with One Mahurangi to look at what we could do differently to achieve better outcomes for the community,” Perera says.

“The option we’re now pursuing meets our needs in terms of our ability to maintain and operate the pipe in the long term, as well as the cost and consenting considerations.”

Over several years, One Mahurangi worked closely with our team, a team of local engineers, and representatives to advocate for an approach that minimises disruption while meeting project requirements. Murray Chapman, manager of One Mahurangi, and co-chairs Dave Stott and Bevan Morrison emphasise this outcome is the result of partnership and persistence.

One Mahurangi manager Murray Chapman says: “This decision shows what can be achieved when everyone works together towards a common goal,” said Mr. Chapman. “We’re grateful for Watercare’s openness and the support of their senior leaders and board chair in working with us to achieve the best outcome for Warkworth.

“From our perspective, we could not have had a better Christmas present."

One Mahurangi would like to thank the engineering team for ensuring practical options were put forward, as well as the thousands of Warkworth residents who supported us by signing our petition. We’d like to acknowledge the ongoing advocacy of Councillor Greg Sayers and MP Chris Penk, and Mayor Wayne Brown, whose support was vital to the project’s success.

“At the heart of this success is the collective effort of a community that cared deeply about getting the right outcome,” Mr Chapman added. “This is a proud moment for Warkworth, showing how collaboration and determination can create a better future for our town.”

The Warkworth growth servicing pipeline is a critical piece of our $450m Warkworth wastewater scheme that completely overhauls how the community’s wastewater is transported and treated. The Warkworth growth servicing pipeline is a large-diameter pipe that will run from the Warkworth Showgrounds in the north to the recently completed Lucy Moore Pump Station.

Recently-completed Lucy Moore Pump Station, which the growth pipeline will connect to

Perera says: “A fully trenchless option was not physically possible, largely due to the topography of the land, and the location of other services, so we will still need to install some of the pipeline with open-trenching along Elizabeth Street and through the Lucy Moore Memorial Reserve to get to the new pump station.”

Several launch and reception shafts will need to be built in the town centre to enable microtunnelling. The locations for these will be confirmed next year as detailed design progresses.

The proposed pipeline route:

• Trenchless from the Warkworth Showgrounds to south side of Hill Street intersection

• Open trench along Elizabeth Street to the Mahurangi River Bridge

• Pipe crossing along bridge over Mahurangi River

• Trenchless installation along Queen Street/Baxter Street to the Lucy Moore Memorial Park

• Open trench installation from the Lucy Moore Memorial Park to the new Lucy Moore Pump Station.

A map of the proposed route

“We will be microtunnelling the entire northern section of the pipeline, including through the Hill Street intersection – and it will be deep enough that it won’t be compromised by any future intersection upgrades.”

What happens next?

Perera says design and consenting is expected to take about a year.

“We know the community will have lots of questions, and we look forward to sharing more information as soon as we have it. There are still key details to be ironed out – including the locations of the shafts we’ll need to build, and the traffic management that might be needed. We’ll be organising drop-in sessions for the community next year, as soon as we have more information to share. We’ll also work directly with impacted businesses.”

The pipeline is expected to be in service in 2028.

“It’s important to understand that this pipeline is about more than enabling growth. It will address a bottleneck that exists in the wastewater network right now and causes overflows to the Mahurangi River when it rains. This pipeline means we’ll have far fewer overflows when it’s in service, so it delivers huge environmental benefits.”

As part of the Warkworth wastewater scheme, our team has already built the Lucy Moore Pump Station, and the Algies Bay ocean outfall. Work continues on the Snells Beach Wastewater Treatment Plant and Warkworth to Snells transfer pipeline. These components of the scheme are expected to be in service by the end of next year.

Snells Beach Wastewater Treatment Plant, currently under construction

Our initiatives to reduce overflows in the meantime

Elizabeth Street pipe upgrades

While design is underway for the town centre pipeline, our team will also deliver improvements to the local wastewater network that will reduce the number of overflows to the Mahurangi River in wet weather.

Three sections of pipes in Elizabeth Street – including the pipe bridge attached to the pedestrian bridge, will be replaced with new, bigger pipes. This work will reduce the need for ongoing maintenance and flushing, and reduce the frequency of wet weather overflows from the Elizabeth Street engineered overflow point.

From mid to late January, we’ll be carrying out topographical surveys to guide the project’s design. In February/March potholing investigations will take place.

These pipe upgrades are expected to be completed by the end of 2025.

Inflow and infiltration investigations

Our team has been inspecting the wastewater network and private properties to identify places where excess stormwater is getting into the wastewater network, contributing to wet weather overflows. Additional manhole sensors that will track inflow and infiltration of stormwater will be installed by Christmas. These will help to identify areas that need to be investigated further.

“Residents can also do their bit to prevent overflows by ensuring their roof downpipes are not connected to their gully traps, and that gully traps are sufficiently raised off the ground. This helps to keep stormwater out of the wastewater network.”