Source: Radio New Zealand
Lake Forsyth in Banks Peninsula following the bad weather. Nathan Mckinnon / RNZ
Residents of a Banks Peninsula town flooded for the second time in a year are questioning why the Christchurch City Council again waited until it was flooded before opening a nearby lake to the ocean.
Little River is again counting the cost of flooding after the town was inundated during the deluge on Monday and Tuesday.
The town of 300 about 30 kilometres south of Christchurch was flooded last May.
But residents said opening Lake Forsyth to the sea could have lowered the level of flooding in the town.
Little River Cafe and Store owner Cameron Gordon. RNZ/Nathan McKinnon
Little River Cafe and Store owner Cameron Gordon – whose business and home had been flooded – said it was clear that Lake Forsyth contributed to flooding in the town.
“Once that lake opened … it drained away pretty quickly,” he said.
“I wish they’d open the lake prior to these events every time. I don’t know what the science is behind their decisions but they seem to have their rules and guidelines about how they monitor all that. But it doesn’t seem to work for us and it seems to be the same story every year with the same excuses every year.”
Lake Forsyth is about a kilometre south of Little River and is fed by the Okana and Okuti Rivers.
The only thing separating its southern banks from the Pacific Ocean is the gravel of Birdlings Flat Beach and a canal connecting the lake and ocean that could be opened by diggers when needed.
The resource consent allowed the council to open the lake when it reached 2.3 metres above mean sea level in spring and summer or 2.7 metres in autumn and winter. But it could also be opened if a storm was predicted to bring it to that level or threaten inundation.
The council did open the lake on Tuesday afternoon after it had peaked at about 4.4 metres and Little River was already inundated.
Gordon said it came too late.
“I think [Lake Forsyth] played a significant role,” he said.
“I think it delays the water flowing away. I don’t think it stops the water coming into the building at first, but I think it definitely slows it receding which is the problem. I think if it was opened before this then we would have had a lot less damage and a lower level through the building. It still would’ve come in but it would’ve been a lot less significant.”
Lisa Ashfield’s second-hand store flooded for the second time in 10 months. Nathan Mckinnon/RNZ
Lisa Ashfield, whose second-hand store had also been flooded for the second time in 10 months, said authorities seemed to be ignoring the experience of locals.
“From what I’ve noticed in 13 years of living here, we’ve had floods, the water’s up really high and you can’t get through the roads, they empty the lake and the water is gone within hours,” she said.
“For everybody to be saying it doesn’t make any difference if the lake is full or not, it doesn’t seem to make sense. It does seem to be that if we had a constant flow of water out of the village, while it’s raining, to the lake and to the ocean it probably could mitigate some of the flooding.
Christchurch Mayor Phil Mauger was not convinced and said the lake’s level was low before the deluge.
“It went from there to up in 36 hours. No one has seen rain like that there,” he said.
“It wouldn’t have mattered what level the lake was, the river – getting it to the lake – was the bottleneck and that’s why all of Little River township got flooded.”
Christchurch Mayor Phil Mauger. RNZ/Nathan Mckinnon
Mauger wanted a diversion installed along the Okana River which could take excess water during heavy rain.
“The climate is getting worse. It seems to be that we’re having a 10-year rain event every three years or two years or whatever, so we’ve got to be starting to be ready for this,” he said.
“That’s why I’m keen on getting this diversion channel dug in the farmer’s land right next to the main road to bypass so it goes to the lake without ruining the road and people’s livelihoods.”
A multimillion-dollar barge and pump project – known as the Ocean Connection – that would allow continual flow of water between the lake and sea was also in its final design stage, he said.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
