Whangārei Urban Flood Strategy
- Project typeStormwater strategy
- Project scheduleLate 2024 to November 2026
We are working in partnership with Northland Regional Council to develop a strategy to manage current and future flood risks in urban Whangārei.
Flooding in urban Whangārei
Whangārei faces significant flooding challenges, particularly in its inner city, much of which is built on reclaimed estuary.
Our long history of flooding is driven by intense rainfall events, which cause ponding, overland flows and rivers overtopping their banks. This is exacerbated by high tides and storm-surge coastal flooding events.
A report published by URS (now AECOM) in 2006 found that the expected damages for a flood event with a 1% chance of occurring in any given year could amount to approximately $138 million in Whangārei.
A risk assessment completed in 2025 found that the expected average annualised loss from flooding in Whangārei is about $45 million.
Previous flood-protection initiatives
Another URS report in 2007 recommended a series of interventions to address current and future flood impacts.
Some of the recommended actions have been completed, including the Hopua te Nihotetea detention dam, Rust Avenue bridge replacement, Woods Road flood wall and various stormwater system improvements. However, many recommended actions, such as storm-surge barriers and pump stations, have not been implemented.
Whangarei District Council is currently investing in stormwater and flood-risk-management systems, such as the Morningside flood-relief project and Northern Growth Area detention dam. The impacts of flooding across many other parts of the city, however, are yet to be resolved.
About the strategy
This strategy will enable a comprehensive, strategic approach to flood-risk management that guides investment in flood-management infrastructure and land-use planning.
The project will clarify the options that could be implemented over time to address surface, river and coastal flooding, and support strategic decision-making by councils.
Due to uncertainty about critical factors, such as population growth and the rate and timing of sea-level rise, the strategy uses the concept of ‘adaptive investment pathways’, combinations of actions that can be implemented over time as needed.
A robust, year-long technical assessment will underpin the development of long-term flood-risk-management options for consideration by both councils. The strategy will inform funding decisions in the 2027 Long Term Plan and infrastructure strategies for both councils.
We are working with experts from BECA, NIWA and Urban Intelligence to develop the strategy.
Timeline
- 2024: Project plan developed
- October 2024 to July 2025: Strategic case and procurement of services
- April 2025 to July 2026: Technical assessment
- July 2026 to November 2026: Business cases.