Changing weather patterns and climate could see more Mataura River flooding events, Environment Southland staff say.
Staff held a drop in centre in Mataura on Friday to listen to residents’ concerns and update them on the progress being made to improve the town’s stopbanks.
Integrated catchment management general manager Paul Hulse said that in the past 20-30 years, river flows had been relatively stable.
However, National Institute of Water and Atmospheric Research (Niwa) data predicted the next 20 years could be different due to climate change.
‘‘We might find we’re having more frequent floods, but also at a higher level and for longer duration.’’
While the stopbanks had done a good job in the past 30 years, with more flooding events they would be under greater pressure, he said.
He would encourage residents to be prepared to evacuate earlier than in the past while how to improve the floodbanks was investigated.
Catchment operations manager Randal Beal said the stopbanks were about 30 years old.
‘‘We need to do a stocktake on the current assets and assess their capability of standing up to future events.’’
It would cost about $110,000 for the assessment, which would hopefully be done before Christmas.
‘‘That will tell us whether we need to rebuild them or come up with a different structure.’’
There was a lack of space to add width to the stopbanks due to nearby features, including buildings, roads and railway tracks, which would make the work challenging, he said.
An assessment had already been completed for the Gore and Waimumu stopbanks.
About 30 residents called in to the drop-in session.
Brian and Kathy Nicholl live on the Gore side of Boundary Creek, about five minutes from Mataura.
In 2020, water from the Mataura River flooded up the creek and entered Mataura.
Earlier this year, the stopbank alongside the Mataura side of the creek had been extended and raised.
The couple said they were concerned that would push even more water into the ponding area near their house.
They were hoping someone would help them in the next flood to move stock and shift their belongings from under their house, which was on stilts for safety.
‘‘We’ve been flooded twice and nobody’s ever knocked on the door and said ‘do you want a hand?’,’’ Mrs Nicholl said.
Mataura resident Alison Bishop said she had already been through two floods.
‘‘I don’t think I could handle it again.’’
She was concerned about the build-up of shingle in the river bank not far from Bridge St.
‘‘It needs to be taken out.’’