Flood Hazard Map
How to View Flood Information on the Map
To see flood hazards for any property:
- Click the Flood Overlay button on the top of the map to activate all flood layers for that region
- Check the Map Legend using the 'i' icon on the right of the map to see what each colour and pattern means for your specific location
Flood Layer Types and Definitions
It's important to note that each council or regional council in New Zealand defines and names flood hazards differently however our legend is set nationally. For example what Auckland Council calls a "Flood Prone Area" might have a completely different name and definition in Christchurch or Wellington. This is because each region has unique geography, rainfall patterns, and stormwater infrastructure, requiring tailored approaches to flood mapping and risk assessment.
Auckland Region
Flood Plains (Light Blue Areas)
Flood plains appear as light blue shaded areas on the map. These are areas predicted to be covered by flood water during heavy rain, with a 1% chance of flooding in any given year - often referred to as a '1-in-100-year flood'. It's important to note that some areas may flood more frequently depending on the local landscape.
Flood Prone Areas (Diagonal blue line pattern on the map)
You'll see flood prone areas marked with a blue diagonal line pattern (hatched areas) on the Relab map. Auckland Council classifies these as low-lying areas where water can become trapped and collect during heavy rain, especially when stormwater outlets become blocked or reach their capacity.
Flood prone areas can occur naturally in the landscape or be created by man-made features such as roads and railway embankments. They can cover extremely large areas, and many properties are built within them.
Overland Flow Paths (Solid or dotted blue line on the map)
Overland flow paths show as solid light blue areas or paths on the map. These represent the routes water naturally takes across the ground during heavy rain when the stormwater network is at capacity, or in areas where there's no stormwater network at all.
Water can move very quickly over land through these paths, creating temporary fast-flowing streams as it travels downhill. When the piped network doesn't exist or its capacity is exceeded, overland flow paths activate as part of our secondary stormwater network.
FAQs
How do i detect flood zones in my area?
To check what flooding hazards may impact your area use the Flood Overlay button on the top of the map view.
Which cities have flooding maps integrated into Relab?
Currently our flooding data is only available in Auckland, Waikato, Christchurch and Wellington
What do the dotted blue lines mean?
The default base map displays various blue features (such as streams, rivers, and cycleways) that are not related to flood hazards. These standard map features can be confused with official flood hazards like Overland Flow Paths. To clearly identify actual flood-related features, switch to the Boundary Map view, which removes these default map elements and provides a cleaner view of flood hazard overlays.
Where is Coastal Inundation flooding hazards found on Relab?
Currently Relab hasn't integrated this data from Auckland Council for Coastal Inundation Flooding Hazards.
What does flood sensitive area mean?
This data layer has recently been removed from Auckland GIS and will soon be removed by Relab.