Nixon Street wastewater upgrade

Project typeConstruction of wastewater pipe and additional required work
Project valueStage 1: $2.389 million (excl GST) Stage 2: $1.5 million
Project scheduleStage 1: To May 2024 Stage 2: From February 2024 to July 2024 Stage 3: From 14 July 2025 to 7 November 2025
Contractor nameParkinson & Holland Ltd (stage one), Loaders (stage two and stage three)
Completion Date07 November 2025

A worker 8 metres down in an excavation at the Nixon and Richmond streets intersection

The Nixon Street wastewater main is a critical asset servicing the entire Whanganui East area. The existing sewer was constructed in 1910 and extends for 911m – from Anzac Parade to the five-road junction at the Raine Street, Wakefield Street, Nixon Street, Burton Avenue and Duncan Street intersection. The wastewater main now needs to be replaced due to its ageing condition.

The project has been split into multiple stages. Stage one covers a distance of 549m from Anzac Parade to Moana Street and installation of the deep main was.completed in 2024. Stage two began in February 2024 and is complete.

Stage one - completed

Due to the depth, condition and location of the main, the construction has been identified as difficult and requiring a high-tech solution. The most suitable solution is micro-tunnelling, which will be done using the Vermeer AXIS laser-guided boring system. This technology is crucial for stage one of the Nixon Street project (see the image above of a worker 8m down.in an excavation).

The Vermeer AXIS guided boring system is a pit-launched trenchless installation method designed to achieve pinpoint, on-grade accuracy while eliminating some of the difficult steps associated with other installation techniques. This means that instead of the entire road surface being disturbed, smaller pits are dug at intervals and the drills lowered into these areas to begin drilling below the road surface. The system is guided by a camera and lasers.

Watch this video from the Vermeer website:

Stage two - completed

Stage two extends for 326 metres from Moana Street to Raine Street and began on Monday, 12 February. It has been completed.
This stage involves the traditional open-cut method as the pipes are not needed to be placed as deep as those in stage one. This work involves not only the installation of the trunk main, but also the installation of a rider sewer at a higher level in the same trench line which will pick up the house connections as the work proceeds past those properties.

Stage three - from Monday 14 July 2025

Work at the Nixon and Millward streets intersection - part of stage three of the Nixon Street wastewater main renewal project - July 2025

Work at the Millward Street and Nixon Street intersection as part of stage three

Stage 3 involves the installation of multiple collector mains also known as rider mains, along Nixon Street, between Anzac Parade and Moana Street.

These smaller pipelines will mostly be installed within the footpath area and at a depth of between 1.5 metres to 2 metres. The collector mains are designed to connect individual properties to the new wastewater main that was installed during Stage 1. While the wastewater main is the primary pipeline that carries sewage to the treatment plant, these new collector lines serve as local connections, collecting wastewater from households and feeding into the larger system.

This work will improve network performance and support long-term service reliability for the area. There will be two main work sites during this stage:

Site one

Location: Intersection of Millward Street and Nixon Street
Work: Improvements to a key manhole to complete Stage 1 work
Contractor: Parker and Holland with Bullocks Group as subcontractor
Timeline: 14 July to 11 August 2025

Site two

Location: Full length of Nixon Street from Anzac Parade to Moana Street
Work: Installation of the collector main and Household Laterals
Contractor: ID Loaders
Timeline: 14 July to 7 November 2025

Benefits and outcomes

Improved system reliability – the replacement of the old sewer main with a new one will increase its reliability and reduce the risk of failure, minimising the likelihood of sewer backups and overflows.
Increased capacity – the new Nixon Street wastewater main from Millward Street to the five-road junction will have a larger diameter and increased capacity to accommodate future growth and development in the area.
Reduced maintenance costs – the upgraded Nixon Street wastewater main will require less maintenance and repair in the long-term, resulting in reduced costs.
Improved environmental impact – the new Nixon Street wastewater main will reduce the risk of environmental damage from leaks and overflows.
Increased community satisfaction – the upgrade of the Nixon Street wastewater main will enhance the overall quality of life in the community and increase satisfaction among residents and businesses.

The catchment area serviced by the Nixon Street wastewater infrastructure

The size of the catchment area serviced by the upgraded Nixon Street wastewater main

Road closures and detours

For stage three, temporary road closures will be in place. However, resident access will be maintained at all times.
Traffic management plans will be in place to ensure safety.

Check our public notices for the latest road closures.