Improving flood flow at the Gore bridges
Environment Southland is working in the Mataura River near the Gore road and rail bridges to improve how water moves through this part of the river during high flows.
Updated modelling identified the railway bridge at Gore as a key constraint during large flood events. When river levels rise, flows back up through the township, increasing pressure on flood banks and related assets.
Works focus on widening sections of the river channel in the reach around and downstream of the railway bridge, including areas near the State Highway bridge. Work will be staged across five targeted areas in the river and includes removal of gravel and sediment build-up.
The works will:
- Widen and reshape parts of the channel to improve high-flow capacity
- Maintain the existing low-flow channel
- Focus excavation primarily downstream of the railway bridge
- Include ongoing gravel and vegetation management to support long-term performance
If you live in the Gore area, you may notice:
- early activity with site establishment before work is visible in the river
- machinery operating in the river
- truck movements to and from the site
- some noise during working hours
- temporary restrictions to river access in active work areas
Traffic management and site controls will be in place to manage safety and minimise disruption. Any changes affecting access or nearby traffic will be communicated in advance where possible.
Hydraulic modelling indicates these changes increase flow capacity through this section of the river by around 13 percent and reduce peak flood levels through Gore. The works improve performance during high flows, but they do not eliminate flood risk.
Ongoing monitoring will support adaptive management of the channel over time.
How long will the work take?
The work is expected to take around four months to complete.
What happens to the gravel?
Material will be dewatered on site and transported off site for reuse.
Will traffic be affected?
No significant disruption is expected. There may be temporary traffic management associated with truck movements, depending on access routes. Public access around the area may be restricted at times.
Will river access be affected?
Yes. Temporary restrictions will apply to river access in active work areas for safety reasons.
Will the work be noisy?
Some noise from machinery and trucks is expected during working hours – Monday to Saturday.
What about fish?
Fish monitoring and relocation took place before the works began, and monitoring will continue throughout the project, with additional measures in place during construction.
Will this work stop flooding?
While flooding is always a risk, this work helps reduce the effects of flooding. Flood risk remains and people should continue to be prepared.
