Kotahi Hazards & Risks

What we know about hazards and risks in our region

Hawke’s Bay is vulnerable to a range of natural hazards. Some are posed by tectonic and geological threats, such as earthquakes, liquefaction, landslips, and tsunami. Other hazards are climate-induced, like droughts, storms, and flooding. And our changing climate is making some of these worse, like coastal inundation and erosion due to rising sea levels. These natural processes can significantly disrupt our lives, our work and communities, leading to increasing occurrences of damage to infrastructure, property and even loss of life.

In New Zealand, natural hazards and risks are managed by many agencies and lots of legislation, including the Resource Management Act. More common hazard events in Hawke’s Bay include drought, coastal erosion and localised storms.

The planning around resource management can play a critical role to reduce the potential adverse effects of natural hazards by effective planning and management of the likelihood and consequences of an event, as well enabling infrastructure – stop banks or dams – to provide some protection to communities from adverse events.

According to a ‘Top Ten’ risk assessment by the HB Civil Defence Emergency Management (HBCDEM) Group in 2021, the top three risks in Hawke’s Bay are:

• Very large near-shore tsunami (~500 year return period or a 26% chance in the next 50 years).
• Earthquake MMI9 (~740 year return period, approx. Magnitude 7.1)
• Very large distant-source tsunami (~500 year return period)

The other risks include volcanic ashfall, moderate earthquakes, moderate tsunami, large floods (~100 year return period) and rural fire in extreme drought conditions.

What the science is telling us

 It is hard to find anywhere in Hawke’s Bay not at risk from one type of natural hazard or another. There are many infrastructural services, businesses, homes and people living in areas at risk from one or more natural hazard. Climate change is aggravating some of these hazards. NIWA identified likely climate change impacts for Hawke’s Bay in 2020, including higher average annual temperatures, increasingly common heatwaves and reduced annual rainfall, but more intense rainfall in storms, and sea level rise worsening coastal erosion.

Kotahi & Hazards and Risks

In preparing the Kotahi Plan, the Regional Council will also provide for the “management of significant risks from natural hazards”. Kotahi must give effect to all relevant national policy statements. For natural hazards, this includes the NZ Coastal Policy Statement, and the National Policy Statements for Freshwater Management, and for Urban Development; noting there is no NPS or similar that relates to natural hazard management.

In short, the Kotahi Plan presents an opportunity to engage with the regional community about the risks ahead, how they are to be managed, to identify and agree what risks are tolerable or intolerable to communities now and in the future, to discuss what risks can be mitigated and which ones must to be avoided, and to explore how any physical works to reduce the risk of natural hazards might be funded.

Your Feedback

The following infographic displays what the community has told us about this catchment in our first round of engagement.  For more information read the full Kotahi Community Engagement Report here.