The Canterbury Regional Council says there was an agreement to open Te Waihora/Lake Ellesmere to the sea last Tuesday but sea conditions prevented it from happening before the rain storm hit.
Environment Canterbury is being criticised for its management of Lake Ellesmere, with people in Selwyn telling RNZ they are frustrated the lake was not opened to the sea earlier.
Taumutu farmer Tim Sanson said there had been good warning that a fairly serious weather system was on the way.
He was expecting around 80 millimetres of rain but received more than 150mm on Thursday, which was “a fairly significant chunk of rain in a short period of time”.
“That is a lot more than what we were expecting from the forecast, that happens occasionally, but to get more than sort of two inches in one hit here, particularly where I live on the coast, is pretty unusual,” he said.
Sanson said the decision-making around opening Lake Ellesmere was a long-running “bugbear” for many locals.
“It’s a bit like having a bucket that’s full of water, you keep putting water in it, it’s going to start running out. Well, if you put a hole in it somewhere, it’ll drain away, and potentially we should be doing that with the lake with a bit more management,” he said.
It was not an easy job to open the lake, which required heavy machinery and hard work, he said.
“It did seem crazy to me watching the bulldozers head down there at high tide. I think it was yesterday morning or the morning before, to start preparing for opening with the southerly roaring in,” he said.
Doyleston’s Tom Dowie, whose home was flooded overnight, said he thought the lake should have been opened sooner.
He woke at 4am on Friday to find six inches of water through his home after a nearby creek overflowed.
His house had since been yellow stickered.
“If the council had opened the lake last weekend when it was nice and sunny, then there would have been far less room for the water to move to the lake and travel on its way out to the sea,” he said.
Pip Adams, who lived near Tai Tapu, also questioned why officials did not act earlier to open the lake before the heavy rain caused widespread flooding.
She said she struggled in vain to get officials to open Lake Ellesmere to help the rising floodwaters drain away on Thursday evening.
She rang the Christchurch City Council and the Canterbury Regional Council after she got home to find water lapping on neighbours’ doors.
The regional council told her it was after hours, to call again in the morning and that the lake’s opening was out of staff hands.
Adams said her property was a disaster zone, her paddocks full of water, with a repair bill estimated to cost tens of thousands of dollars.
When can Te Waihora/Lake Ellesmere be opened?
The council used diggers to create a channel between the lake and sea at certain times, governed by a 1990 water conservation order and resource consents held jointly with Te Rūnanga o Ngāi Tahu.
ECan general manger of hazards Leigh Griffiths said consultation for a lake opening began on Monday and by Tuesday afternoon, a joint decision had been made to open the lake.
“We can only open the lake once a joint decision has been made, and the lake height reaches a minimum of 1.13m (from 1 April to 15 June). The lake conditions were not met until Tuesday 30 April,” she said.
Griffiths said earthworks had begun to open the lake but in current sea conditions it would not be successful because the cut would fill in and it was unsafe for people to operate machinery in the surf zone.
“We are watching conditions closely and the lake will be opened to the sea as soon as weather and sea conditions allow. This is likely several days away at the earliest,” she said.
RNZ also approached Ngāi Tahu for comment.
Emergency Management Minister Mark Mitchell said he was confident officials had made the right call not to open Te Waihora/Lake Ellesmere to the sea earlier.
Mitchell met Environment Canterbury staff and mana whenua on Friday about the lake.
“It is very apparent there is a lot of work and focus on how they manage Lake Ellesmere and the fact that there was a request to put in to widen that access,” he said.
“All the information that they had in relation to that was what informed their decisions and they’re all united in the fact that they’ve done the right thing and they’ve made the right decisions and they’ve done what they could.”
Mitchell said he had full confidence in that decision but he was prepared to hear more about the community’s concerns over the the lake’s management.
rnz.co.nz
