​ ​ ​ ​ ​

Alert

High River Watch

Our High River Watch has been activated

Contact

Search

Mataura River flood resilience project

Flood events in the Mataura catchment are projected to become more frequent and more intense over time. Recent upgrades have improved flood management infrastructure in priority locations, but updated 2D hydraulic modelling shows that constraints in the river system can still cause water levels to build up and place pressure on flood banks and other infrastructure during large floods.

The Mataura River Flood Resilience Project focuses on addressing these pressure points and guiding staged investment across the catchment over time to reduce flood impacts and inform future catchment-wide decisions.

The current phase includes:

  • Completed channel improvements at the Gore road and rail bridges.
  • Applying catchment-wide hydraulic modelling to understand how the system performs during large events.
  • Further infrastructure improvement works where modelling shows they will have the greatest impact.
  • Planning for how engineered measures and nature-based approaches may work together over time.
  • Developing the Mataura Blueprint, a long-term pathway for managing flooding and its effects across the Mataura, to guide future decisions and investment.
Mataura River at Gore showing the five targeted areas for channel improvements

Mataura River at Gore showing the five targeted areas for channel improvements

Latest update – September 2026

The main channel improvement works at the Gore road and rail bridges are complete.

A total of 21,850 m³ of sediment was removed from the river channel to improve how floodwater moves through this constrained section of the Mataura River. Gore District Council has reused the material as capping material at its retired landfill site.

The contractor has completed the main works and left the site. Disturbed riverbank areas will be re-grassed in late spring when conditions allow.

The improvements help reduce the effects of flooding, but flood risk remains.

Read the media release: Gore channel improvement work completed.

Understanding flood risk and planning for the future

Updated 2D hydraulic modelling is being applied across the wider Mataura catchment, including Gore, Mataura and Wyndham.

This modelling allows us to:

  • Assess flood risk and the capacity and performance of existing flood management infrastructure.
  • Identify constraints and priorities for further investigation and potential improvements.
  • Inform development of the Mataura Blueprint to help guide future flood-risk decisions and investment.

Mataura Blueprint

A long-term pathway for managing flooding and its effects across the Mataura catchment

Environment Southland is developing the Mataura Blueprint to help guide future flood-risk decisions and investment.

The Blueprint will bring together technical information, community perspectives and cultural, environmental and economic evidence to develop a shared understanding of current and future flood risk.

It will take a mountains-to-sea view of the Mataura system, recognising that what happens in one part of the catchment can influence flooding elsewhere.

The work will consider a range of possible responses, including flood management infrastructure, nature-based approaches, preparedness and land-use responses.

Strengthening flood monitoring across the catchment

The Mataura Flood Warning Network Resilience Project is being delivered alongside this work and will improve flood monitoring across the catchment.

Upgrades to river-level and rainfall monitoring will improve the reliability of warnings, support Emergency Management and enable more informed decision-making during severe weather events.

Partnership and funding

On 16 October 2025, new co-funding for flood resilience work was confirmed through Kānoa – the Regional Economic Development & Investment Unit (MBIE) under the national Resilient River Communities initiative.

The Mataura River Flood Resilience Project is co-funded through the Regional Infrastructure Fund (RIF) and Environment Southland as part of this national programme.

The project builds on established collaboration with Gore District Council, Southland District Council and Ngāi Tahu ki Murihiku, supporting a more holistic, catchment-wide approach to flood risk reduction over time.

Previous upgrades in the Mataura catchment

Earlier co-funded upgrades restored agreed levels of service in priority areas of Gore, Mataura township and Wyndham between 2021 and 2024.

Detailed design and modelling report

The Gore bridges channel improvements were developed using detailed hydraulic modelling undertaken by Land River Sea Consulting.

Download the Gore – Mataura River Widening Final Design Report 2025 (PDF)

The report sets out the design for widening the Mataura River channel at and downstream of the Gore railway and State Highway bridges. It assesses hydraulic performance across a range of flood events and maintains the existing low-flow channel while reshaping selected parts of the wider channel to improve performance during high flows.

During construction, the proposed work in Area 1 was reviewed further because of its proximity to the Gore District Council stormwater outfall and the State Highway bridge pier. That review resulted in a reduced scope for Area 1 while retaining the majority of the hydraulic benefit from the wider channel improvement works.

The detailed design report follows an initial 2024 investigation into the Gore rail bridge capacity. Download this report here.

That work identified limited capacity through the bridge reach as an important contributor to flood risk in Gore during large events and assessed options for improving channel capacity around and downstream of the bridges.

Share this

Share this page

Sharing...