Wairau Valley Branch Sewer Transmission Renewals

Project overview

Watercare is rehabilitating the Wairau Valley Branch wastewater network to improve the condition and reliability of existing wastewater infrastructure, reduce the risk of overflows, and help protect local waterways and the environment.

The programme is being delivered in stages across Wairau Valley, Tōtara Vale and Unsworth Heights, with work taking place along multiple sections of the wastewater network.

Most of this work is being completed using trenchless technology, which allows pipes to be renewed underground with minimal excavation and reduced disruption to surrounding communities.

The project includes pipeline rehabilitation, manhole improvements and associated renewal works across public reserves, roads, berms and selected private properties.

Where access to private property is required, Watercare and its contractor will work directly with affected owners and occupiers.

Benefits

This project will help:

• Reduce the likelihood of wastewater overflows

• Improve environmental outcomes and water quality

• Extend the life of critical wastewater infrastructure

• Improve the reliability and resilience of the wastewater network

What we are doing

The project team is rehabilitating sections of the Wairau Valley Branch wastewater network using trenchless relining technology and associated manhole improvements.

• Current and upcoming works include:

• Pipeline relining between existing wastewater manholes

• Investigation and cleaning of wastewater assets

• Manhole rehabilitation works

• Works within Unsworth Park and surrounding areas

• Property-specific works where access is required to maintain or renew wastewater infrastructure

• Final reinstatement of affected areas following construction activities

Most works are undertaken from existing manholes, reducing the need for extensive excavation.

Stage 1 works

Stage 1 of the Wairau Valley Branch wastewater renewals commenced in April 2026 and involves rehabilitation of approximately 1.0 kilometres of wastewater pipeline between manhole (MH) 28 and MH11 of the pipeline. The works include pipeline inspection and preparation, trenchless relining using spiral wound lining technology, manhole rehabilitation and reinstatement of affected areas upon completion.

Stage 2 works

The second stage of the renewals commenced in July 2026 and is a continuation of the Stage 1 works, starting at the end point of Stage 1, MH11, and rehabilitating the pipeline all the way to MH 1 at Rosedale Wastewater Treatment Plant. Like Stage 1, the works include pipeline inspection and preparation, trenchless relining using spiral wound lining technology, manhole rehabilitation and reinstatement of affected areas upon completion.

What happens next

Construction will continue through the remaining sections of the wastewater network over the coming months.

Upcoming activities include:

• Continued pipeline relining works across both stages of the programme

• Manhole rehabilitation works and renewals works

• Works within Unsworth Park and surrounding reserve areas

• Final reinstatement and rehabilitation activities following completion of major construction works

Where private property access is required, the project team will contact affected owners and occupiers directly before works commence.

Construction timeframes remain subject to weather, ground conditions and operational requirements.

See the map of the proposed work area below:

Stage 1: View full sized map

Stage 2: view full sized map

How will these works affect you?

As work progresses, you may notice:

• Temporary traffic management in some locations

• Construction noise during working hours

• Crew vehicles accessing work sites

• Temporary fenced work areas within reserves and public spaces

• Occasional wastewater odour when manholes are opened

Most activities are short duration at each location before crews move to the next section of the network.

Water and wastewater services are expected to remain operational throughout the works.

Residents and property owners directly affected by upcoming works will receive notification before construction begins.