As the massive clean-up continues in Wairoa, residents are starting to question whether the flood that inundated hundreds of homes and businesses was caused by Genesis Energy, not Cyclone Gabrielle.

When the Gisborne Herald visited Wairoa’s flood-stricken North Clyde area yesterday, several residents said they were concerned the power company might have made a poorly-timed decision to open a floodgate at its Lake Waikaremoana dam, creating the sudden surge of water that spilled over the banks of the Wairoa River.

Genesis Energy says it was not responsible for the flooding and that hydrology data showed the excess river flow came from tributary streams beneath its lowest power station.

Michelle McIlroy was among those who expressed concern about the possible floodgate scenario, saying residents would be asking questions of Genesis.

She wondered if the dam had been at capacity and if there had been a need to let water out, why it wasn’t done ahead of the cyclone.

“It could’ve been at capacity and they would’ve needed to let the water out, but they should’ve warned us because they could have killed people — if it was that.”

Michelle McIlroy, right, and her family in front of their yellow-stickered home in Wairoa after Cyclone Gabrielle. Photo / Gisborne Herald

People were constantly being told to prepare for the cyclone. If Genesis knew there was going to be 200 to 400 millilitres of rain, it should have been releasing water ahead of it, she said.

But Genesis chief operations officer Rebecca Larking said, “our resource consents require us to manage the level of Lake Waikaremoana, which in turn helps manage the flow of the Waikaretaheke River, which flows into the Wairoa River. The discharge through the Waikaremoana Power Scheme was less than 1 per cent of the total flow at the Wairoa township during Cyclone Gabrielle. A lot of the water that enters the Wairoa River flows in through tributaries below Genesis’ control points on the Waikaremoana Power Scheme.

“During the cyclone, Genesis released between 35 to 40 cubic metres of water per second from Lake Waikaremoana as required by our consents.

“By the time the Wairoa River entered Wairoa township, it had peaked in excess of 6500m3 per second, (according to the Hawke’s Bay Regional Council river flow data), showing how much water entered the river further downstream, outside of Genesis’ points of control.”

Lake Waikaremoana near Wairoa. Photo / Glenn Taylor, File

McIlroy’s house in North Clyde and her 84-year-old mother’s house beside it were the first in the firing line when the river breached its bank at a bend by the showgrounds about 6am last Tuesday and made a beeline for the sea.

Four hundred houses were inundated — half of them uninsured, their occupants typically in a lower socio-economic group, McIlroy said.

Most were mana whenua (born and raised in the area, like their family before them) so wouldn’t want to leave.

Diggers and work crews are now trying to unearth properties from the brown wasteland of silt that has blanketed the entire area “like a war zone”, McIlroy says.

She and her mother might be able to return to houses, which were surprisingly only yellow-stickered — not fully condemned.

They’re among a group sheltering at their marae,Te Poho O Hinewai, which was unaffected by the flood and had teamed up with Wairoa District Council to become a hub for the recovery effort.

McIlroy says the “silent, creeping” way in which the flood suddenly advanced is what made her question its origin.

At 5.45am, her husband and son went to work and all was well. It seemed Cyclone Gabrielle had passed through without any real incident.

At 6am, her sister luckily got up and noticed water in their yard. It was rapidly getting deeper but wasn’t a noisy, debris-laden torrent like the flood in Hawke’s Bay.

“When we were getting inundated it was just water and it rose really quickly.

“If you were asleep, it would have killed you. You wouldn’t have known it was there until it was in your house,” McIlroy said.

The streets of Wairoa are inundated with silt after Cyclone Gabrielle. Photo / Gisborne Herald

She tried twice to phone 111, then realised the power was out, cell tower signal had gone and they would have to save themselves — and anyone else they could.

As they drove away the river followed them. They beeped their horn and yelled for people to get out. McIlroy ran into properties, banged on windows and screamed that emergency services wouldn’t be coming.

“People were asleep. I was waking people up, running into their houses and screaming wake up. I knew they had old people in there.”

The danger was hard for people to believe because there was no rain and it was fine outside, she said.

This flood was nothing like Cyclone Bola, which she remembered from her 20s. There was no rain. It was low tide — the full tide wasn’t until 12.30pm that day, McIlroy said.

She and her sister had been “river people” all their lives. They had checked on the river late last Monday night and it was low.

“We knew the rain was coming but we thought we’ve got enough time to go check back in the morning, but by then it was too late.

“I’ve always worried about the [Genesis] dam and if we have flood events. My mum was in Bola [too] and she said this was 10 times worse than Bola.

“Our house then never got anything in it.

“This time it was just a silent killer.”

Asked how she was coping, McIlroy said: “You have your moments, when you see a photo that can’t be replaced, when you’re standing in other people’s clothes, but it’s alright, nobody died.

The Piripaua power station between Lake Waikaremoana and Wairoa operated by Genesis. Photo / Supplied, File

“You rebuild and the thing is these people we’re working with, they’re all in the same boat, so you can’t feel sorry for yourself. You just gotta carry on and we’ll think about it later.”

Genesis also noted that the team at its Waikaremoana Power Scheme was isolated at times as communications were cut off but they were able to keep the power stations generating as much electricity as possible to help supply the East Coast and Hawke’s Bay, working closely with Transpower to get power from the scheme to those who needed it.

“In partnership with MB Century, we were able to get water, food, and other supplies into Tuai village for staff, contractors and the community,” Larking said.

- Gisborne Herald