Customer: Auckland Council Healthy Waters Contract: Construct Location: Henderson, Auckland

Fast Facts New 713 m stormwater pipeline under Border Road A 2100 mm in diameter Micro–Tunnel Boring Machine (MTBM) will install the pipeline Three shafts will be constructed for the tunnelling drive A 240 m, 450 mm low flow pipeline will be constructed by horizontal directional drilling

The Corban Reserve Stormwater Upgrade Project involves the installation of a new 713 m stormwater pipeline under Border Road in West Auckland using a 2100 mm diameter MTBM.

The existing stormwater network between Corban Reserve, Murillo Reserve and Border Road Esplanade Reserve in Henderson cannot cope during heavy rain causing localised flooding, property damage, and impacting on water quality in Opanuku Stream. A new, larger diameter pipe along Border Road has been installed to increase the capacity of the network, reduce flooding, and improve water quality in the stream.

Now completed, the new pipeline will reduce flooding in the area, increase capacity within the network to allow for future growth, and protect and enhance both Opanuku and Waitaro streams. It will also prevent landfill gases and leachate entering the stormwater network, making it safer to maintain.

The MTBM used on the St Marys Bay project in 2020 was upcycled for this project to tunnel from Imperial Place to Border Road Esplanade. This is an environmentally and socially complex project with residents, local schools, native wildlife and flora, and park users all neighbouring the three worksites. The project team has carefully designed the methodology and construction programme to take into account the local community, the ecological and man-made surroundings.

The project is split into two phases:

Stage One:

• Construct a new pipeline network from Imperial Place to Border Road Esplanade Reserve along Border Road.
• Construct a low-flow pipeline to connect the main pipeline to Murillo Reserve.
• Upgrade the pedestrian bridge between Spode Place and Imperial Place.
• Upgrade Murillo Reserve, daylighting Waitaro Stream and add new planting and pathways.
• Upgrade Border Road Esplanade Reserve with additional planting, a new boardwalk and a walkway connecting the reserve with Taranui Place.

Stage Two:

• Decommission the old Corban Reserve stormwater pipe.
• Upgrade the reserve re-contouring slopes and adding widespread planting, new paths, and drainage.

The project was completed in February 2024.