Experts take to skies to create flood maps of Auckland

Auckland Council is taking to the skies again to deploy state-of-the-art LiDAR (Light Detection and Ranging) technology to map critical waterways.

It's part of the Council's Making Space for Water Programme – a response to the 2023 Anniversary Weekend floods – to ensure flooding on that scale doesn't happen again by combining infrastructure upgrades with the use of natural environments.

"As we rely more and more on these natural networks to do the work of stormwater to convey flows, we need to understand how they're able to cope," said Auckland Council's principal of waterways planning Danny Klimetz.

The LiDAR technology provides virtual walk-throughs of stream networks to detect changes, helping enhance flood resilience across Auckland.

Auckland already utilises some regional LiDAR data, but these data sets are 20 times more accurate.

"We knew we needed something better," said Klimetz. "Something with more density."

His team connected with the University of Canterbury, which has been using state-of-the-art LiDAR tech for stream management.

"We've used it from anywhere to do change detection on braided rivers in the South Island, we did a lot of the emergency surveys after Cyclone Gabrielle, trying to figure out where stop banks had failed and where stop banks were going to be needed," said Justin Stout, a geospatial research scientist at the University of Canterbury.

Earlier this year, a low-flying EC120 helicopter equipped with LiDAR sensors was gathering high-resolution data across approximately 328 square kilometres of the region, covering areas from Matakana and Whangateau in the north, to urban catchments like Swanson and Meola Creek.

This time the data is being collected from a 233 km2 area including all of the North Shore, parts of Henderson Creek and Whenuapai as well as areas around Pukekohe.

“This data will help us visualise and understand the intricacies of Auckland’s waterways in a way that hasn’t been possible before, right down to individual trees, slips, and bank conditions. It will equip us to tackle the challenges of urban flooding and climate change head-on," said Auckland Council's health waters manager Craig Mcilroy.

“It’s a game-changer for managing flood risks and ensuring the city’s resilience for future generations."