The severe weather events in early 2023 and extreme weather events across the motu since then have shown us all the devastating impact landslides can have on homes, communities, infrastructure and public spaces.
Landslides are on ongoing risk for much of Aotearoa and Tāmaki Makaurau is one of the country’s most landslide-prone regions. Our varied geology, steep coastal and inland slopes, weathered soils and exposure to intense rainfall all contribute to landslide risk.
Chief Engineer at Auckland Council Ross Roberts explains that while landslides cannot be completely prevented, improving our understanding of where they are most likely to occur helps support better planning, better decisions and more resilient communities.
“We've always had landslides, but the severe weather events in 2023 demonstrated to Aucklanders the scale of the consequences,” says Mr Roberts.
“One of the lessons for us is while we cannot prevent every landslide, we can get better at knowing where the risks are and making sure the information doesn't fall through gaps, ensuring that we manage the land properly and helping Aucklanders understand what they can do to help themselves.
“No council can eliminate all landslide risk nor predict every individual landslide. However, there are ways we can better understand and manage the risk.”
Managing, mitigating and understanding the risk
Hazard information cannot predict exactly when a landslide will occur, how large it may be, or the impact it may have on a particular property or person, but it can help identify areas that may be more susceptible to landslides.
Auckland Council uses a range of tools and approaches manage and mitigate the risk, and ongoing investment in science continues to drive better understanding of this risk.
This includes land-use planning and building controls, management of council-owned land and infrastructure, emergency management, hazard mapping, specialist engineering and scientific advice, public information and targeted monitoring of higher-risk locations. These activities sit within a broader risk management framework designed to ensure risks are identified, assessed, owned and managed appropriately.
Since 2023, Auckland Council has significantly strengthened its understanding of landslide hazards across the region.
- New susceptibility maps for both shallow and large-scale landslides have been developed and published.
- Landslide information has been added to Land Information Memoranda (LIMs).
- Quantitative risk assessments have supported recovery and planning decisions.
- Proposed planning changes are also intended to strengthen how natural hazards are considered in future development.
Continually improving our approach
Managing a complex risk like landslides requires continuous improvement.
Work is currently underway to strengthen natural hazard management at campgrounds, holiday parks and other council-operated overnight accommodation sites. This includes additional assessments, monitoring and operational procedures to support decision-making during severe weather.
The council has considered the findings of the recent external review into the Mount Maunganui Beachside Holiday Park landslide, and what the recommendations in the review mean for an Auckland context.
“Auckland Council has many of the recommended risk management systems and processes already in place or under development. We're using this review as an opportunity to test and challenge our systems to identify where they can be improved,” says Mr Roberts.
Auckland Council is also:
- developing a new public Natural Hazards Viewer
- improving hazard information available through LIMs
- reviewing its Natural Hazard Risk Management Action Plan
- strengthening organisation-wide oversight of natural hazard risks through a new Auckland Council Enterprise Risk Solution system.
As climate change increases the frequency and intensity of severe weather events, the risk of landslides will change over time. Auckland Council will continue investing in managing landslide risk to build our resilience.