Why is a work programme needed?

The debris flow impact in Roxburgh is not just theoretical- it has happened before, and it is expected to happen again. 

  • Past events: Since 1938, debris flows have damaged homes, roads, orchards and essential services in Roxburgh. 
  • Community concerns: After the debris flow 2017 event, many residents remain concerned about the potential impacts on safety, property and infrastructure. 

That’s why we have created this programme to work together to understand, prepare for and manage the impacts of debris flows hazard in the area. 

The map below shows the catchments in the area likely to experience debris flows:  

 

Map of the catchments susceptible to debris flows in the Roxburgh area. Yellow indicates the catchments active during the November 2017 events (these are analysed as part of the interim management plan), pink indicates the additional catchments incorporated in the detailed debris flow hazard and risk assessment, and blue indicates the other catchments assessed during the prioritisation process but not included within the scope of the current investigations

 

Programme purpose

The programme involves two technical projects to help manage the debris flows:

  1. The interim creek monitoring and maintenance plan. The purpose of this plan is to keep the creeks clear and working properly so they can effectively carry floodwaters during a debris flow event.
  2. The Roxburgh debris flows detailed hazard and risk assessment. Primary objective of this project is to assess 13 catchments to inform debris flows hazard management for the area.

Progress of the programme so far

  • The interim creek monitoring and maintenance plan is progressing. LiDAR acquired in late 2024 has allowed for geomorphic analysis of the lower reaches of the Roxburgh creeks. These results were used by ORC Natural Hazards and Engineering teams to define areas for interim maintenance. 
  • The detailed debris flow hazard and risk assessment has completed some work including gap analysis and hydrogeomorphic modelling. It now focuses on qualitative and quantitative assessments and producing a comprehensive, technical report.  

Programme stakeholders and partners

ORC is working closely with Central Otago District Council (CODC) and other stakeholders including Civil Defence Emergency Management Otago (CDEM), New Zealand Transport Agency Waka Kothi NZTA) and the Roxburgh community to deliver this programme.  

ORC is also working with mana whenua representatives such as Aukaha and Te Ao Marama to make sure that mana whenua are updated all programme progress and technical findings so that they can make informed decisions.  

What’s next

  • Continue work under the interim creek monitoring and maintenance plan.
  • Once the technical assessment report is ready, ORC and stakeholders including CODC and CDEM will hold community sessions to share findings (this is expected between September and December 2025).

How you can get involved

  • Attend our community sessions (in person, and online)
  • Give feedback on the new technical findings
  • Share your local knowledge of past events or known trouble spots in the creeks

Where to find more information

Access other pages of this site or contact ORC Natural Hazards team on 0800 474 082 or email us at naturalhazards.enquiries@orc.govt.nz for more information.  

Fan apex. Unnamed creeks between Pumpstation and Slaughterhouse Creeks—looking at where the creek exits in hill country and begins to flow across the alluvial fan