Glenbrook watermain replacement

Why is the project needed?

The project relates to replacing the damaged 200mm network watermain crossing the Taihiki Estuary between Waiau Pa and Glenbrook Beach and improving network resilience for the region’s water and wastewater supply. The watermain is the sole conveyance of supply to Glenbrook Beach, and without it, the community relies on water being transported to the reservoir in tankers.

The water pipeline, which was anchored onto the seabed was subject to significant tidal influence and had multiple leaks relating to holes and damaged joints over the last few years.

Several options for the alignment and methodology were considered as the original alignment was unable to be constructed due to erosion of the cliff face on the Clarks Beach side.

Horizontal Directional Drilling (HDD) was identified to be the preferred option over anchoring to the seabed.

Key benefits include:

• Reduced impact on the environment

• Ease of operational and maintenance requirements

• Better health and safety outcomes

What's happening?

Our construction partner, CDS, will be starting work in April, and we estimate the project will be completed by approximately end of October 2024. A drill rig will be situated on the reserve at 77 Tahuna Minhinnick Drive, Glenbrook Beach.

First, a deep 300mm hole will be drilled under the Taihiki River appearing at Wharf Road at Waitete Pa. A pipe, which has been assembled on this side will then be pulled back through the cavity towards Glenbrook Beach. This will then be connected to the existing infrastructure to provide a permanent long-term water supply.

July update: week commencing 1 July

The team is working hard to have the second pilot hole completed by tomorrow (Tuesday 2 July). Once that is done they will switch to the reamer which is used to clean out the spoil from the bored hole. All that mahi means you will see a lot more truck movements on the roads between now and Friday 12 July. Pipe welding will start this Friday 5 July. There will be some pipe welding carried out on Saturday 6 July and the aim is for that job to be completed by Thursday 11 July. Once the pipe is welded, it will be pulled from Waitete Pā to Glenbrook Beach. That’s when the process starts all over again for the third and final pipe.

How will this work affect you?

• Working hours will be from 7am to 6pm, Monday to Saturday.

• These works will generate some noise, however levels will be kept to a minimum and in accordance with Auckland Council and consent requirements.

• Traffic management will direct traffic around the works particularly when large trucks are travelling to site.

• The reserve on the Glenbrook Beach side will be fenced off, however, the path will remain open.

• During the work, temporary footpaths and road surfaces may not match existing pavements. Please be assured that any temporary surfaces will be returned to their original condition or better by the end of the project.