Renewing our sea defences

Wellington Airport is investigating options for renewing our seawalls and defences which protect vital infrastructure against erosion and inundation.

These coastal defences were established between 50 and 70 years ago. Engineering advice and peer review has confirmed they are reaching the end of their natural lifespans and need replacing.

This work is essential to increase our resilience and adaption to climate change, given that sea levels are rising and the frequency and severity of storms is likely to increase.

As well as protecting the airport, they also protect Moa Point Road, Moa Point Road tunnel, stormwater infrastructure and major sewage pipes to the Moa point wastewater treatment plant which treats most of Wellington’s sewage.

The three main areas of our coastal defences (marked below) are the Southern seawall, Western seawall and Lyall Bay breakwater.

Southern seawall

Last year we commenced public consultation on options for the southern seawall which we are progressing first. The other two defences (Lyall Bay breakwater and Western seawall) will be progressed later.

Following public consultation and research over the last 12 months, we are now seeking resource consent to overlay the existing southern seawall with large armour units (with the exact size and shape to be determined during design), and rock. Thank you to everyone who took part in our survey, attended a community meeting and/or sent us feedback.

In order to maintain the integrity of the existing seawall, the new armour units will be overlaid on top of the existing structure. The width of the seawall will therefore extend seaward by approximately 15 – 25 metres, and the length of the seawall will extend eastwards approximately 100 metres to cover a section of coastline currently unprotected (marked above as ‘eastern area’).

We currently have modelling underway to investigate what (if any) impacts there could be on surf and are working with the Wellington Boardriders Club on this.

We are also commissioning assessments into any other environmental effects this project could have, including (but not limited to):

• landscape and visual amenity
• marine ecology
• avifauna (birds)
• cultural values
• archaeological and heritage values
• construction noise, vibration and transportation
• coastal processes
• economic impacts

Consenting process

This month we have lodged an application for this project to be listed in schedule 2A of the Government’s proposed fast track legislation. This could enable the project to be processed in a more timely and cost-efficient way, while still ensuring all appropriate environmental considerations are taken into account.

Whether the project is accepted into the schedule of the fast-track legislation and whether we decide to go through the fast-track process or not, we will continue to communicate and engage closely with the local community, iwi and stakeholders.

Further timings

The construction is dependent on the earlier stages of planning, design and consent. Subject to consent approval, enabling works to facilitate construction could begin in mid-2025 or 2026.

This is a major project with different stages to work through. Construction itself is likely to span across multiple years including enabling works in advance of the main project .

As indicated last year, we are likely to use the southern half of Miramar Golf Course for construction laydown areas, and the casting and storage of armour units and rock. This land comes into possession of the airport from 1 January 2025.

Impacts on local residents

Construction methodology is still to be confirmed, but once underway the work is likely to involve temporary lane and/or road closures around the area, increased heavy traffic at times and some construction related noise.

As with all airport projects, we will keep the community informed and will have specific plans to minimise noise and disruption as much as possible.

Further information

Further detail is available in this publication here, and more detailed designs of the options are available in this presentation which were discussed at two public meetings in 2023.

Please feel free to send us any questions, comments or feedback via wellingtonairport@wellingtonairport.co.nz.