Hydrologist Craig Goodier believes a logjam was the most probable cause of the blockage. Photo: ALEXA COOK / RNZ
A pile of logs that may have blocked the Esk River mouth is in the spotlight at an inquest into the deadly Cyclone Gabrielle, with the victims' lawyer suggesting material from a concrete dump could be a factor.
The coroner's inquest is underway at the Hastings District Court, examining the factors that led to 13 people dying in relation to the cyclone.
One of the lives claimed by the cyclone on 14 February, 2023, was two-year-old Ivy Collins. As her parents fled the floodwaters on North Shore Road in EskDale, Ivy was swept to her death.
Two-year-old Ivy Collins drowned as a result of flooding during Cyclone Gabrielle. Photo: Supplied
Susane Caccioppoli also died in the Esk River, further up the valley, where she was house-sitting with friend Gareth Jones.
Exactly how and why the area around North Shore Road flooded is still unclear.
The inquest has heard two theories about what may have caused the Esk River to flow back into the area around North Shore Road, filling it with deep floodwaters.
The area around North Shore Road and Pohutakawa Drive flooded in the early hours of 14 February 2023. Photo: Supplied
Hawke's Bay Regional Council hydrologist Craig Goodier said the flooding was caused by a logjam blocking the Esk River mouth.
The logjam was a pile of woody debris that washed down Esk River in the flood from the catchment area, where there were forests, but during the inquest, the families' lawyer, Jane Glover, suggested material from a concrete dump may have been a factor.
She said an existing 'clean fill' site - where concrete from demolished buildings was processed - was located near the river mouth.
Glover said material from the site could have stopped floodwaters from escaping out to sea.
Imogen Collins is lifted to safety from the rooftop her family climbed onto to escape the floodwaters on North Shore Road. Photo: Supplied/NZDF
- Independent inquiries found widespread failures from Hawke's Bay councils and civil defence that put hundreds of people's lives at risk
- An independent flood review of Hawke's Bay recommended the concrete dump 'clean fill' site be reviewed by the regional council
- Earlier evidence from hydrologist Craig Goodier revealed he took two hours to tell civil defence about a river monitoring equipment failure
Glover cross-examined Goodier on Wednesday, querying how he came to the conclusion that a 'log raft' caused the flooding around North Shore Road.
Glover: "Did you speak to anyone who saw the log raft?"
Goodier: "No."
Glover: "So that's just an assumption based on what you've seen of logs in the ocean, plus the height of the river?"
Goodier: "Yes."
The Regional Council hydrologist believes the logs pictured in the waves, could have blocked the Esk River mouth earlier on in the flood. Photo: Supplied
Upon further questioning, Goodier was asked if anyone disagreed with his theory. He said no colleagues had, but he was aware of other opinions that the flooding could be related to the concrete dump.
Glover told the court about how locals claimed, around the time of the cyclone, the concrete dump was up to eight metres high in places, with piles of 'clean fill' large enough that you couldn't see a 12-tonne digger behind them.
Concrete piled at a 'clean fill' site after Cyclone Gabrielle. Photo: Supplied
Goodier told Glover, if the information about the concrete dump blocking floodwaters was critical, there should have been a better investigation, with more data collected.
"I accept that, if that investigation came back and found something different, and provided more info, I may change my mind.
"As of right now, with the information that I have, I would think it is very heavily weighted in favour of the log raft being the reason and very minor in terms of the concrete," he said.
Flood review called for concrete dump review
Following the cyclone, a Hawke's Bay Independent Flood Review recommended the regional council review current resource consents that relate to the risks to flood management, and ensure appropriate consent conditions are in place and being complied with.
"For example, the clean fill operation at the mouth of the Esk River should be reviewed."
The report also said HBRC needed to appropriately monitor and enforce third-party resource consents that affected flood risk. Through interviews carried out for the report, it noted members of communities and businesses spoke of concerns about river mouths not being cleared before the cyclone.
"Examples of observations were: The Esk River mouth being blocked or severely restricted relative to river flow from the catchment area, meaning floodwater had nowhere to go, but back into the Esk Valley."
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