Coastal erosion is a natural process where waves, tides, and currents reshape shorelines by removing sand and rocks from beaches and cliffs. Over time, this erosion can impact property and infrastructure.
In the Bay of Plenty, climate change is accelerating coastal erosion, with rising sea levels and increasingly severe weather making these events more frequent and damaging.
Natural buffers like sand dunes play a crucial role in helping coastlines recover after storms. Through Coast Care, a coastal restoration program in partnership with local communities, local authorities, and schools, we’re working to restore and protect sand dunes along Bay of Plenty beaches.
New coastal erosion maps will be available on our BayHazards viewer in late 2025. These maps are based on expert modelling and will show areas that could be affected by this hazard over the next 100 years, as the climate changes.
Although the maps will show future scenarios, as a community it's important to start planning now to ensure new development is resilient and long-term risks are managed. Emergency Management Bay of Plenty also uses these maps to help keep the public informed and prepared for these hazards.
The coastal erosion maps will show areas along the coast likely to be affected by this hazard during an extreme event, based on three climate scenarios: present day, 50 years and 100 years in the future.
These future scenarios account for sea level rise and long-term erosion, which can cause the shoreline to shift inland.
Why has Regional Council produced these maps?
Regional Council has updated the coastal erosion maps to ensure the community has access to the best and most accurate information. It is also a legislative requirement by the Resource Management Act (RMA) that we identify natural hazard areas in our region.
Where can I go to view these maps?
The interactive maps will be able on our BayHazards viewer in late 2025. When live, you will be able to search by property to see what hazards may apply.
How will councils use this coastal erosion information?
The coastal erosion information and maps will be used in the following council processes:
What climate change projections for sea level rise were considered?
The future climate change projections for sea level rise are based on future greenhouse gas emission scenarios (known as Representative Concentration Pathways or RCPs). The coastal erosion maps use a range of projections, including where a medium global effort is made to reduce carbon emissions (RCP 4.5) to where a minimal global effort is made to reduce carbon emissions (RCP 8.5).
For example, will we continue to burn fossil fuels at an ever-increasing rate, or will we shift towards renewable energy? The RCPs try to capture these future trends. They make projections of how concentrations of greenhouse gases in the atmosphere will change as a result of human activities and how this will affect global warming and the amount of sea level rise that occurs in the future.
How accurate is this information?
The coastal erosion modelling was carried out by experts Tonkin + Taylor, using best practice methods. It is based on the best available data, including beach profile surveys, LiDAR terrain surveys and historic aerial photos of long-term shoreline change. Because future hazards are uncertain, the maps show a range of likelihoods from likely to very unlikely.
This mapping is less certain around streams, and river mouths, which are highly dynamic features influenced by river and coastal processes. These areas may appear as gaps on BayHazards, with site-specific mapping recommended (shown as a dotted line on BayHazard).
Will this information affect my property value or insurance?
Property values are usually influenced by a range of factors, including the state of the economy, interest rates, income levels, and population changes. While many New Zealanders enjoy living near the coast, it’s possible at some point that some coastal properties at risk of natural hazards may no longer become as desirable.
When it comes to insurance, the Council cannot provide advice on how this mapped information may affect insurance premiums or a property owners ability to obtain insurance. We recommend contacting your insurance provider directly to discuss your specific policy.
In general, individual contracts are reviewed annually and are based on current risk. Therefore, the coastal erosion maps that model changes over 50 and 100 year timeframes should not be used to analyse short term risk for insurance purposes.
Deep South National Science Challenge has developed an easy-to-read information sheet for homeowners, with important frequently asked questions about how insurance companies might respond to increasing climate hazards. Read more about house insurance and climate change.
