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Roxburgh Hazard Management
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Understanding the debris flood hazard, options to manage, and reduce risks to the Roxburgh community.
Julion from our Natural Hazards team explains what an alluvial fan is and why debris floods occur.
February 2026
PDF | 1007 KB
January 2026
1-E0173.00
PDF | 23 MB
Hydrogeomorphic Modelling and Quantitative Risk Assessment Report. WSP New Zealand Limited (WSP) has been engaged by ORC to complete hydrogeomorphic hazard modelling and risk assessment for 13 alluvial fans that lie adjacent to the Clutha River along the base of the Old Man Range in Roxburgh. The study has been carried out in stages, and this report presents the hydrogeomorphic modelling and the findings of the risk assessment for the 13 catchments.
What you can expect
Live in Roxburgh or the Teviot Valley? An invitation to attend the community events will be in your letterbox from 9 Feb.
| Date | What’s happening |
|---|---|
| 9 Feb 2026 | Community event invitations delivered (Roxburgh and Teviot Valley) |
| 11 Feb 2026 | Full technical report published |
| 11 Feb 2026 | Summary of key information published |
| 13 Feb 2026 | Natural hazard maps published on Natural Hazards portal |
| 18 Feb 2026 | Community events: Drop-in session and evening presentation |
Roxburgh sits on land known as alluvial fans. Alluvial fans are formed by the sediment from mountain streams accumulating over a long time. This creates fertile soil and natural drainage, making the area well-suited for farming, gardening and everyday living.
Living on these alluvial fans comes with challenges. The Roxburgh area is exposed to natural hazards- such as debris flows and debris floods. These can be dangerous because they are unpredictable; they can happen quickly and with great power, posing a risk to infrastructure, homes and lives.
Alluvial fans, debris floods and debris flow-type processes have always been here and are naturally occurring. We're working to understand more about the risks and the impact they could have for the community.
Otago Regional Council (ORC) is leading a work programme to better understand these alluvial fan hazards and look at ways to manage and reduce their impact on the Roxburgh community. We will also be going out to the community to discuss our 2026 risk assessment and share the findings.
This work is carried out in partnership with Central Otago District Council, NZ Transport Agency Waka Kotahi, Civil Defence Emergency Management, hand in hand with the Roxburgh community.
- A new study has been completed for 13 catchments in the Teviot Valley looking at debris flood hazard and risks. The new mapping identifies areas more likely to be affected by debris floods and the possible effects on people, places and key infrastructure.
- Regional alluvial fan hazard information for the Teviot Valley has been published by Otago Regional Council) since 2009, including on Alluvial Fans | ORC AGOL Natural Hazards Portal
- The new detailed mapping for 13 alluvial fans is complementary to and refines the regional data.
- Areas of higher hazard and significant risk are identified in all 13 creeks. Risk is generally higher closer to the creek channel but each fan is unique.
- Communities and residents are encouraged to get familiar with the new maps and findings, and share knowledge with neighbours.
- Detailed risk and hazard mapping is available above for the 13 catchments
- The study methodology for natural hazard risk assessment is consistent with ORC partially operative Otago Regional Policy Statement (APP6 in pORPS).
- APP6 specifies a 4-step process, including an initial Qualitative Risk Assessment as a screening tool. For higher risk areas, the last step is a Quantitative Risk Assessment where risk levels are calculated spatially and output is maps of Annual Individual Fatality Risk (AIFR) and Annual Property Risk (APR). This type of detailed approach is consistent with best practice such as GNS Landslide Planning Guidance 2024.
- The potential impacts of climate change are included, as required by partially operative Otago Regional Policy Statement (pORPS).
- Risk maps are shown for two scenarios, Present Day and RCP8.5 (high climate emissions track).
- A trigger for debris floods is intense rainfall in one hour. Triggering rainfall may occur more often under climate change scenarios.
- This new information helps councils and infrastructure providers make good long-term planning decisions. It complements regional alluvial fan information that has been available since 2009 (Alluvial Fans | ORC AGOL Natural Hazards Portal)
- Hazard and risk information could be used by decision makers when considering: emergency planning, natural hazards management, land-use planning, infrastructure planning and construction; and building consents.
- If you are planning to build, extend or develop your property, Central Otago District Council can advise what this means for you.
- The new study does not require anyone to move or relocate.
- Communities and residents are encouraged to get familiar with the new maps and findings, and share knowledge with neighbours.
- If you are in a hazard area, consider preparing your household and your work by having an emergency plan Get prepared — Get Ready (NZ Civil Defence) — Emergency preparedness in New Zealand
- If you are in a hazard area, consider preparing your household and having an emergency plan Make a household plan — Get Ready (NZ Civil Defence) — Emergency preparedness in New Zealand
- Check information from your local community response group.
- Sign up for CDEM alerts (https://www.otagocdem.govt.nz/useful-stuff#emergency-mobile-alert-ema)
- NZTA upgraded several culverts following debris floods in November 2017 to enhance capacity and resilience.
- However WSP notes that culverts along SH8 have historically impeded debris flood flows, causing inundation upstream and laterally from the culvert location in the channels.
- As part of the new study, WSP carried out a Qualitative Risk Assessment that includes an assessment of the potential impact on lifelines, consistent with ORC methodology (pORPS APP6). Inundation of sections of SH8 is identified for all catchments. Shallow debris flood inundation is likely to be cleared quickly (<1 day). Deeper and more extensive inundation is associated with greater damage and longer service outage. Table 49, Table 50 and Table 51 describe the impact on lifelines for the three scenarios.
- Yes, new natural hazard information with go on LIMs
- Local Government (Natural Hazard Information in Land Information Memoranda) Regulations 2025 sets the requirements for providing natural hazard information in LIMs.
- Regional alluvial fan hazard information for the Teviot Valley has been published by Otago Regional Council) since 2009, including on Alluvial Fans | ORC AGOL Natural Hazards Portal
- The new detailed mapping for 13 alluvial fans is complementary to and refines the regional data. The new information is consistent with the regional data.
- Insurance companies often use a range of information when they assess risk, and hazard reports are only one part of that picture.
- The new study does not automatically change your insurance. We cannot say how individual insurance policies may be affected, as decisions are made by insurers on a case-by-case basis. If you have concerns, you may choose to discuss your cover with your insurer or a broker.
- You can also contact our Natural Hazards team on 0800 474 082 or email us at customerservices@orc.govt.nz
- If you or your group has specific concerns we can get together for a chat.
- ORC webpage for self-study Debris flood hazard in Roxburgh
- ORC Natural Hazards Database hazard mapping (search by address or place) Alluvial Fans | ORC AGOL Natural Hazards Portal
- No decisions have been made yet regarding follow-up work.
- Your feedback, concerns and suggestions will be an important part of the process.
- ORC will continue to work closely with Central Otago District Council (CODC), Civil Defence Emergency Management Otago (CDEM), New Zealand Transport Agency (NZTA) and communities on ongoing natural hazards management and how best to use the new findings.
- Further work may include developing short-term action plans and utilising longer-term decision-making and funding processes (e.g. council’s Long Term Plans).
- CDEM will update the Teviot Valley Emergency Response Plans to reflect the new findings and to raise awareness of facilities identified to support the community’s welfare needs.
- Keep your eye out for updates in the Teviot Bulletin and orc.govt.nz/roxburghhazards (please share this link with interested people).
Debris flood hazard in Roxburgh
Learn about the debris flood that affect the Roxburgh area, why they occur, and what risks they pose.
Debris flood hazard management programme
This section outlines the goals, approach and progress of the hazard management programme so far.
Investigations and reports
Find key programme progress reports presented to Council, along with presentations presented at community meetings, then explore the range of technical studies undertaken by Otago Regional Council and specialist consultants.
Get Involved
Stay up to date with the latest news, opportunities to give feedback and attend events.
Who’s on the Team
Meet the people working together on the Roxburgh Debris Flows Hazard Management Programme.
