Council pleased with flood protection schemes

The Otago Regional Council says its flood protection schemes performed well during the recent deluge.

Parts of Otago received up to 210mm of rain over 48 hours last week, causing widespread and substantial flooding.

The council has more than 200km of floodbanks, some of which are being assessed for damage.

Engineering manager Michelle Mifflin said the council’s flood banks held up despite mounting pressure, and there were no uncontrolled breaches or failures observed during the peak of the event.

But the council was yet to fully assess any community concerns, damage and how they performed locally, she said.

A complete assessment might not be available for weeks, but any useful information would be included in the council’s flood repair programme if relevant.

"There’s still a lot of struggles and distress out there for some people. We’re continuing to work proactively with communities to ensure water drains away as quickly as possible, at this early stage of recovery," she said.

Flood scheme checks started three days before the deluge hit and were being assessed along with the rivers 24/7 until late on Sunday.

Ms Mifflin was pleased with the proactive communication with landowners and communities, including a community meeting at Paretai Hall about alleviating flooding that was building up.

"Being able to talk to locals firsthand about local conditions and their concerns was invaluable," she said.

"We were able to hear their concerns and work directly with the community on solutions to alleviate the extenuating circumstances with flood waters, which included us discussing the risk and consequences around different options."

Contractors then opened up a flow path through the Training Line infrastructure Koau Mouth of the Clutha River to release water from the Puerua and Barrata Rivers. That work was aimed to reduce more severe disruptions for nearby communities, while council-owned portable pumps were used to assist with floodwaters around the Clutha District.

Science and resilience general manager Tom Dyer said the duration and amount of rainfall was difficult to forecast, and snow melt and already saturated soil made predicting the effects uncertain.

Flows in the Leith Flood Protection Scheme peaked at about 70 cumecs, which was well within its capacity.

"We were pleased with how the Leith scheme operated, especially following earlier redevelopment works which had been completed since the mid-2015 flood event." — RNZ