National flood risks & climate change

Emergent exposure of flood inundation hazards under future climate change in New Zealand

Floods are some of New Zealand’s most frequent, most damaging and most disruptive natural hazards. As our climate changes, flooding caused by both increased rainfall and rising sea levels – in coastal areas and on floodplains – is expected to increase.

Man stands knee-deep in flood water

As floods worsen, so will the social, cultural, economic and environmental consequences. Pinpointing exactly which areas are most at risk can be difficult, especially as extreme weather events become more frequent and less predictable.

There’s not a lot of information currently available to central and local government about exactly what infrastructure is at risk. The information produced through this research is urgently needed to help identify high-risk areas and prioritise mitigation and adaptation efforts.

This project has produced flood maps and models that allow practitioners and researchers to identify how flood risk may evolve in their area. These models determine which assets – like buildings, roads, bridges and railway lines – are at risk, on both a regional and national level.

We have created digital elevation models using data collected from councils across New Zealand. We have completed coastal and fluvial/pluvial flood inundation mapping, as a crucial step towards developing a nationwide flood hazard map.

The models produced by this research will be available in open access software called RiskScape, developed by NIWA and GNS Science, to directly help those people whose job it is to manage flood risk. If we can accurately predict the areas of highest risk, we can adapt, minimising harm to New Zealand’s population and economy.


This project in the media:
People, roads and billions in assets vulnerable to climate change-related floods Stuff
New reports map cost of flood risk under climate change TVNZ
Huge risk from rivers and rising seas Radio NZ Morning Report
New reports map cost of flood risk under climate change Radio NZ
Rising seas: NZ must 'put brakes on' coastal development NZ Herald
River flooding in Canterbury potentially most damaging in NZ Stuff
New NIWA study shows 800,000 Kiwis at risk of flooding in coastal areas NewsHub
7000 buildings at risk for every 10cm sea level rise Newsroom
125,000 buildings at risk from first metre of sea level rise Newsroom
Reports warn about devastating impact of climate change on properties Insurance Business NZ
New Zealand: New reports highlight flood risk under climate change Prevention Web (UNDRR)
Climate change costs are hitting households through insurance premiums Stuff
NZ close to breaking record for annual storm damage cost only halfway through 2018 TVNZ
Funding announced for climate resilience research

Research and findings:

For project data, please contact Ryan Paulik directly.  

Deep South Challenge seminar:
Watch a video of Ryan Paulik presenting his findings at a Deep South Seminar, in August 2019:

Sea level rise PLUS big storms: What exactly are we in for?