As the impact of flooding continues to be felt through Auckland Airport, the company says work it has underway will minimise risks of a repeat.
It says upgrades to its stormwater systems will ‘’enable the international terminal to remain above flood levels for future modelled climate change scenarios”.
It says it ‘’takes seriously’' its role as New Zealand’s main international gateway and points out a second runway, if and when built, will be up to nearly four times above the mean high-water level the current one is in places.
But an engineer who specialises in climate risk and adaptation says the airport needs to completely rethink future building and how it operates its assets now.
The 57-year-old airport is critical to the country handling about 75 per cent of New Zealand’s international passengers and 62 per cent of domestic traffic. Billions of dollars worth of freight passes through it every year.
When the unprecedented deluge hit last Friday, all flights were suspended for part of last weekend, initially after landing lights were knocked out by an aircraft landing but then the crisis cascaded as the international terminal was inundated.
Airlines are still scrambling to recover their schedules and thousands of passengers had travel disrupted and bags have been flood-damaged. Airlines and the airport have taken fire all week from customers for their response.
Today, the airport said mops and sucker trucks have been replaced by tradies as the assessment and repair work gets underway at the international terminal.
It is warning of continued disruption.
Crews are removing flood-damaged carpet and lower sections of wall linings across the ground floor of the international terminal and in limited areas of the domestic terminal.
“Some of the work will be back of house, but it will also need to be carried out in areas used by travellers and the public inside our international terminal, such as the check-in and arrivals hall,’’ said chief executive Carrie Hurihanganui.
To defend the terminal in the short term against further flooding, drains have been checked for debris after they were overloaded last week and emergency pumps are also on standby.
The airport company says its executives are too busy for in-person interviews but in a written response to the Business Herald, a spokesperson said it was very sorry for the for the distress and disruption.
Niwa has described Auckland’s summer worth of rainfall in a single day as a one-in-200-year event and the spokesperson said staff were able to safely drain flooding of up to 1m in and around the international terminal within three hours.
‘’This was an exceptional response in very difficult conditions.’’
Niwa is forecasting heavy rainfall and possible flooding for the North Island through to April.
Auckland Airport fits the profile of many other airports around the world which need large areas of flat land; it is close to a large body of water, some of its runway is built on reclaimed land and much terminal activity is at ground level for ease of entry and exit.
Much of the 1500ha of its land is concrete runway, aircraft apron, roads, carparks and vast roof areas on terminals, hotels and warehouses which collect rain that needs to go somewhere.
What the models warned
In previous sustainability and annual reports, the airport acknowledged the risks of climate change.
‘’As a result, physical inundation and flooding of assets due to sea-level rise and extreme weather events is one of our key climate-related risks. Our business model is built on the operation and development of aeronautical infrastructure and commercial property; this means impacts from sea level rise and extreme weather events could significantly affect our business operations.’’
In its 2022 annual report, the airport modelling identified that without intervention, infrastructure close to or draining to the coastline will be subject to more frequent and severe flooding and inundation in the long-term, around the year 2110.
‘’However, near- term planned upgrades to the stormwater network and surrounding infrastructure and further long-term flood management responses will provide sufficient mitigation for this risk,’’ the report says.
The airport is about to start work on a $1b domestic jet terminal connected to the international terminal, scheduled for completion around 2030.
It is negotiating with airlines the final details of the project, which they pay for and then pass on charges to passengers.
The airport has been asked whether flooding at the weekend would change the approach to designing the new terminal but the spokesperson said executives couldn’t respond this week.
But in a general response, the spokesperson said the airport had significant new stormwater capacity planned for future projects, and when the review is completed, it would be able to assess if any changes are required.
The spokesperson said the company commissioned a climate change study in 2019 to understand the flooding and inundation risk in critical areas (such as the runway and apron) and advanced further studies to determine the extent of flooding and inundation under low, moderate and high climate change impact scenarios.
‘’These studies told us that our infrastructure was sufficient to cope with climate change events under all scenarios until 2046.‘’
Based on these studies the airport said it started to proactively commence works, with major upgrades in place and others planned by 2025 to ensure it was prepared for a worst-case climate change scenario.
‘’We have been carrying out substantial stormwater network upgrades in parallel to our infrastructure development programme to improve resilience against flooding. These will enable the international terminal to remain above flood levels for future modelled climate change scenarios.’’
Recent roading developments included work to improve the stormwater systems and build additional stormwater capacity. Seawall maintenance included upgrades to future-proof against sea level rise.
‘’We are continuing to plan well ahead of significant climate impacts with our capital plan through major upgrades that we are currently consulting on our capital plan with airlines.’’
The spokesperson said if and when Auckland Airport built a second runway, the runway’s concept design set finished levels at between 9.5m to 15m above sea level.
It has long had a sea wall around the perimeter of its airfield and says seawall maintenance also includes upgrades to future-proof against sea level rise.
Not only is the airport critical to New Zealand’s economy, but more than 600,000 ratepayers and investors have a financial stake in it.
Since its sharemarket listing, the airport has been popular with small investors – about 43,000 hold 5000 shares or less – but it remains 18 per cent owned by Auckland Council on behalf of ratepayers.
Auckland Mayor Wayne Brown has mooted selling down that shareholding and his office has been approached for comment on the resilience of the airport and whether this would affect thinking on offloading shares.
There’s been no response from Brown, an engineer who campaigned on being Auckland’s ‘’Mr Fixit.’’
The putting right that counts
One engineer who specialises in risk and adaptation says the floods are a massive wake-up call.
Tom Logan, a University of Canterbury senior lecturer in civil engineering, says airports are especially vulnerable given their location – often by the sea.
‘’Events like this, such as tsunamis and coastal flooding from sea level rise are going to become massive problems for them,’’ he said.
Critical assets such as Auckland Airport are not going to be able to be moved so the onus was on preventing or protecting them from a repeat of Friday’s floods.
Logan said flood barriers, having sandbags at the ready as a bare minimum and then developing wetlands, using more porous paving or starting to raise the floor level in new terminal upgrades should be considered.
‘’Having said that, with the amount of rain that Auckland got there’s only so much that a storm water pipe or a wetlands can handle – that’s where we get to a point is: How do you design to accept and live with it?’’
He said “accepting and adapting” meant designing infrastructure so that it’s fine to flood and water goes away and clean-up is easier.
‘’Once we accept that it will fail then it’s a matter of how fast we can get it back online. In an airport building you’ve got baggage conveyer belts that could be hosed down between events. ‘’
Auckland Airport could look at relocating more of its operation to the second floor of its building but that meant there would be a financial trade-off.
Christchurch Airport, the country’s second biggest, was impacted by earthquakes in 2010-2011 and its chief executive Justin Watson said aviation is based around interconnected networks, so the impact of events in one place cascade across the entire network.
Christchurch handled diverted aircraft during the weekend.
‘’The earthquakes taught us the need for resilience and being well prepared to deal with an increasing number of low probability/high impact events. This means having a very good understanding of all the risks and how to handle them,’’ he said.
Engineer Logan warns another challenge will be to avoid a knee-jerk reaction in Auckland, known as the disaster-driven response.
‘’What we will see is people demanding action and politicians want to look like they’re acting but often that doesn’t lead to real solutions. They can be inefficient or maladapted, inadvertently making the problem worse,’’ he said.
‘’A disaster is an opportunity to have the conversation about long-term resilience and make sure we’re not rushed into anything.’’