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Auckland Airport has completed a significant programme of major stormwater upgrades, boosting the precinct’s resilience to extreme weather and improving the quality of water flowing into the Manukau Harbour.
An additional 4.4 kilometres of stormwater pipes – many large enough to stand upright in – have now been laid underground in the west of the precinct, forming a critical part of the airport’s 150km-strong stormwater network. Together with improvements to multiple stormwater ponds and a new innovative stormwater treatment system, the project provides added resilience to the impacts of climate change and improves the airport’s ability to manage water sustainably.
“Not only does Auckland Airport connect almost 19 million people and $26.6 billion worth of trade every year, but it is also a lifeline utility for our city,” says Chief strategic planning officer Mary-Liz Tuck.
“As New Zealand’s gateway airport, we need to be ready for more frequent and more severe weather events, and these upgrades are a vital part of that resilience.”
The Auckland region was tested in early 2023, when a month’s worth of rain fell in just a few hours. Stormwater systems across the city were overwhelmed including at Auckland Airport, leading to flooding at the international terminal and causing significant travel disruptions for passengers.
“Experiencing the flooding was an incredibly challenging moment for travellers and everyone operating at Auckland Airport. However, like other infrastructure owners in the Auckland region, it’s ultimately sharpened attention on how we plan infrastructure in the face of more extreme weather events.
“For Auckland Airport, we chose to bring forward our planned stormwater upgrades and upsize designs. It’s also brought more focus to how we approach stormwater upgrades and renewals as part of our wider infrastructure programme, ensuring we are responding to the changing climate and building a robust and future-ready airport.”
Since 2023, Auckland Airport has worked to install the additional 4.4km of pipes to the north-west of the international terminal, along with expanding stormwater ponds to improve stormwater management.
Alongside this, the airport has also constructed a Coupled Wetland Biofilter system on the edge of the Manukau Harbour, the first-of-its-kind in New Zealand.
Designed to manage stormwater from more than 100 hectares of land, including the airport’s international airfield, the coupled wetland biofilter mimics natural processes to clean stormwater before it flows into the Manukau Harbour.
Mary-Liz says with a footprint of 14 Olympic swimming pools, the coupled wetland biofilter was designed to do more with less land, freeing up space for aviation growth while providing enhanced treatment of stormwater entering the harbour.
“What’s remarkable is that within this compact footprint, the system can treat more than three times the volume of water compared to a traditional pond,” she says. “That’s down to smart design and it means we can keep building for New Zealand’s future aviation needs while strengthening environmental outcomes.”
The coupled wetland biofilter treats stormwater by removing sediments and contaminants in three stages.
Water first slows through a sediment forebay, then flows into a wetland planted with 20,000 native plants. In heavy rain, water spills into biofilter cells, where it filters through soil layers before flowing into the Manukau Harbour. To safeguard aircraft operations, 20,000 square metres of bird netting span the system.
Mary-Liz says performance of the biofilter will be closely monitored through seasonal weather cycles, with results informing future upgrades across the wider stormwater network.
“This is a long-term commitment to protecting the environment while enabling progress,” she says. “We’re building not just for today, but for the future of air travel, our communities, and the harbour we’re proud to sit beside.”
Mary-Liz says sustainable water management was an ongoing priority in a location of both cultural and ecological importance. She said the airport worked with iwi to ensure cultural and environmental guidance shaped the design of the biofilter, including the installation of a cultural marker to acknowledge archaeological discoveries at the site.
