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.

Latest update (Tuesday 3 September)

We will be completing the last pipe pull on Wednesday 4 September. This will be a long day with a slightly earlier than normal start for the crew, so they can complete the work in a day. They'll then start removing equipment from the site starting with the big stuff which will mean truck movements on both sides of the river. The following week, 9 – 13 September, the valves which enable the pipes to be connected into the network will start being built. This will also mean additional truck movements to bring the required shingle to site. This work is expected to be completed by the end of September.

In October, the team will continue removing equipment and tidying the work areas. The barrier fencing will be removed, however, the silt fencing will remain until the grass has regrown.

All works should be completed on schedule by the end of October.

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.