A review of the severe flooding that affected Kumeū and Huapai in August 2021 is complete. This review was commissioned by Auckland Council's Healthy Waters team. It aims to understand:
- the causes of the flooding
- potential opportunities to reduce flood risk.
About the event
On the evening of 30 August 2021, a severe rainstorm hit west Auckland. This caused significant flooding of Kumeū and Huapai and prompted an
Auckland Council Emergency Management response.
A review of the flooding event was undertaken as part of a wider council initiative to improve flood resilience in Kumeū and Huapai.
Key findings of the review
A severe weather warning from MetService prior to the storm allowed us to clean critical
culverts and inlets before the event.
Largest rainfall recorded for area
The rainfall was the largest ever recorded at this location. It was an event statistically expected to occur less than once in a hundred years.
Flood impacts in line with modelling
Despite its severity, flood impacts were generally in line with those modelled and predicted for an event of this size.
The one exception is the flooding south of the railway in the showgrounds and Shamrock Drive area. The flood impacts here were worse than predicted, mainly due to
hydraulic modelling limitations at the time our flood maps were prepared.
Urban development over the past 10 years has been guided by our flood maps and these areas have generally fared well.
Kumeū River floodway
During the event, the partly completed Kumeū River floodway did reduce the severity of the flooding.
If completed, the floodway may have reduced flood depths by between 0.1m and 0.86m, depending on location.
But due to the magnitude of the August 2021 storm, considerable flooding would still have occurred.
Stormwater review and improvements
Our flood models will be updated based on the results of the review.
These improved models will be used to:
- review flood mitigation options for Kumeū and Huapai
- create and publish revised floodplains
- understand the costs and benefits of the complete floodway project.
Models will be ready in the next four months, with the aim of having a final assessment completed by the end of 2023.
Ongoing maintenance
Our Healthy Waters team conduct pre and post-storm clearance checks on the public stormwater network's critical inlets and outlets.
We want to know about any potential blockages, damage to stormwater assets and flooding as soon as possible. You can
report a problem online or contact our call centre on 09 301 0101.
We have contractors available at all times to respond to emergencies.
What you can do to help
Watercourses, natural waterways and overland flowpaths that travel over (or next to) private property are the responsibility of the property owner.
You can help prevent flooding by keeping waterways clear of debris and blockages.
Get a copy our private watercourses guide
