South Otago residents keen for flood-prevention action

Otago Daily Times

a day ago

By Tess Brunton of RNZ
South Otago residents want action as they prepare to face more flooding and other hazards in the future.
The Otago Regional Council is developing a strategy for how vulnerable communities in the Clutha Delta can adapt.
A public drop-in session was held in Balclutha yesterday so locals could hear about the mahi (work), ask questions and tell the council what they wanted to see done.
Dave Inder farms next to the Clutha River in the delta and has watched his property disappear under water more than once.
"We have to make decisions according to the temper of the river. It's quite simple really, I mean you can't be complacent," he said.
"It doesn't have to be local rain, it can be rain in the west and it's a huge influence on us and the people below us, they're even worse."
Those downstream had a tougher time getting rid of the water as they could also face big seas and backflows, he said.
Sometimes rainwater became trapped on the wrong side of the floodbanks and they struggled to get rid of it.
"The Clutha wasn't really in flood but our local rivers were and the delta filled up and we couldn't get the water out.
"There are pipes there that were not satisfactory, but they hadn't been satisfactory for a flood like that for many years."
He has been meeting with the Otago Regional Council to solve the issue and headed to the drop in session in the 'Big River Town' for answers.
"The regional council come with ideas, plans and all sorts of things, but nothing's fruited yet," he said.
"Snow melt could be on the way again - so there are a few anxious farmers and we just want to know if they intend to fulfil their promises."
But he was keen to work together to find solutions and said that was the way forward.
Groundwater could be high in parts of the low-lying floodplain and drainage could be difficult.
The area has several active faults and could also be vulnerable to storm surge or tsunamis from the Pacific Ocean.
The Lower Clutha Flood Protection and Drainage Scheme drains more than 9000ha from north of Balclutha to the sea and was designed to mitigate flooding from Mata-Au/Clutha River.
The council's natural hazards manager, Dr Jean-Luc Payan, said an adaptation plan was about more than flood banks and drains.
It looked at how to keep hazards away from people, allow water to safely leave and, in some cases, how to get people out of harm's way, he said.
"That's really the purpose of the strategy, understanding the current environment, how this environment is going to change in the future, what people value in the area, how they see their future, and how we can combine those tools to have a safe environment in the Clutha Delta," Payan said.
But it was a challenge - the Clutha is a powerful body of water.
The delta was at the end of the catchment that was fed from big lakes in Queenstown and Wānaka.
"All that water that falls on the alpine area will end up in the Clutha."
A common theme at the session was people asking if the flood protection scheme was operating as planned, he said.
The council recently published a study that showed current sediment levels were not impacting the flood capacity of the river, Payan said.
But business-as-usual maintenance and work would continue in parallel to the mahi on the strategy, he said.
Dairy farmer Thomas Marshall lives at the mouth of the Clutha in Paretai.
Flooding could leave paddocks out of action for six months, taking away half his income, he said.
"It's been hard trying to get any maintenance done for years now and it's just cost us a lot of money in flooding and it just gets really frustrating," he said.
He would like to see the council ramp up its efforts to maintain the flood protection scheme.
Balclutha resident Stephen John said it was unreal to see the Clutha River in flood.
"Last big flood we had, what was that? 1998,1999? and to see it right up the top of the river banks, right round through here... so scary."
He was keen to understand the hazards facing his community.
"Just to catch up with everything that's going on and how we're helping things and, yeah, how scared we should be or not because I'm living down on the flat now."
Balclutha resident Pip Martin was encouraged to see the mahi under way to come up with an adaptation strategy and keep the community informed.
He was worried about the maintenance of a nearby floodbank. It appeared lacking in the past, culminating fears it might fail and resulting in him evacuating during one of the last floods, he said.
Payan said the strategy was in the early stages and the council was working to understand the current environment and how it was expected to change.
It was similar to the work the council had been undertaking in South Dunedin, Middlemarch and Glenorchy.
With the final strategy a few years away, it wanted locals to help to shape the future of their community.