How much will it cost?

The project is currently funded for $116 million in the Greater Wellington Regional Council’s 10-year plan. At this stage of the project, the full cost remains uncertain, but will become clearer as the design is developed over the next few years.

What is happening now with the project?

A comprehensive route option assessment process is underway which will be followed by selection of the preferred route and development of the concept design for the preferred route. Once we have that concept design, we will be able to prepare detailed costings for the Greater Wellington Regional Council’s 10-year plan. If the project gets the green light, Wellington Water will proceed with final design of the whole project, then apply for the relevant consents.

When will construction start, and when will it be finished?

Investigations are currently underway to determine the best locations for the supporting infrastructure and pipeline itself, which will be followed by design and cost finalising. We expect the construction work to start in 2022 with completion by 2025.

How much extra water will need to be extracted from the Waiwhetu Aquifer?

None.The volume of water extracted from the Waiwhetu Aquifer after completion of the cross-harbour pipeline will remain the same as the existing extraction permits. That is because this pipeline simply provides an alternative route to supply Wellington City.

Is it risky?

In New Zealand, we know a lot about designing, installing and maintaining undersea pipelines and cables. We have them all around the country’s coastline carrying our electricity, telecommunications and energy resources such as oil and gas – all vital to our daily lives and our economy.

The cross-harbour pipeline is a little unusual in that it will carry drinking water, but we have world-leading engineering expertise in this field. Thanks to the exploratory harbour bores carried out in 2017 and 2018, we also have a very comprehensive understanding of the sea bed and aquifer in Wellington Harbour

What impact will it have on the marine environment and aquatic life?

Our priority is to ensure construction of the pipeline will have a very minimal and temporary impact on the marine environment and the aquatic life - and that we can mitigate any of those impacts. 

To help us do that, marine scientists have carried out extensive work, mapping the seabed along a 200m wide corridor as well as rocky shore subtidal ecologies at the pipeline’s potential take-off and landing areas at Point Howard and Evans Bay. These surveys are helping us to understand the ecology of the areas, and determine the best locations for the supporting infrastructure and pipeline itself. The data will also help inform environmental management aspects of applications that need to be submitted as part of obtaining resource consents.