Progress made on Mataura River flood protection projects

Rock protection work along the true right bank of the Mataura River at Mataura is about to get underway.

Last year, while a geophysical report found there was no obvious structural damage to the stop banks on the Mataura River as a result of the 2020 flood event, river engineers raised concerns about a 600m section along the true left bank in the Mataura township that was at risk of erosion.

This work was prioritised and completed in March, while work on the true right bank was planned to be completed in the 2023/34 construction season.

Environment Southland integrated catchment management general manager Paul Hulse said recent flooding has increased erosion in this area and we want to get the work undertaken as quickly as possible.

Around 32,600 tonnes of rock will be used to protect a 710m stretch of river bank along the true right, and is expected to take around four months to complete.

While the protection work is underway, community safety is paramount.

“Heavy vehicles will be moving in the area around the Alliance Group Mataura Plant, so please take extra care.

“In terms of flooding potential, our message to the Mataura community remains the same: ‘Be prepared to evacuate your homes at lower river flows than you might have in the past, and at short notice,’” Paul Hulse said.

Emergency Management Southland will make any decisions about when and if to evacuate and will lead any evacuation. Each situation will be assessed on a case-by-case basis, as it is not possible to predict conditions for every situation.

River levels are monitored 24/7 by the Environment Southland hydrology team who notify Emergency Management Southland of rising river levels/flows.

Mataura residents on both sides of the river should be prepared to evacuate. Residents are advised to have a plan, gather supplies and to get connected online (go to cdsouthland.nz). Being prepared will help to make any evacuation easier and less stressful.

In addition to the Mataura protection work, construction on a new stop bank along Ontario and Toronto Streets in Gore to replace the existing concrete flood protection wall is underway.

Gravel is also being extracted from the gravel island downstream of the Mataura bridge and will be used in the new Gore stop bank construction.

“It is great to be able to deliver two infrastructure improvements at the same time, repurposing gravel that would not normally be utilised,” Paul Hulse said.

“The council has worked closely with Hokonui Rūnanga to prepare a plan to remove the gravel as the Mataura River is a mātaitai reserve and an important spawning area for kanakana.”