THE amount of rain that fell on Kawerau on Friday night, turning streets into raging torrents that tore through homes, has been put at 450 millimetres and 470mm by two Doug Wilson Crescent residents.
Residents in Beattie Road and Doug Wilson Crescent say stormwater measures behind their homes failed to cope with the deluge and at about 4am water started pouring through sections and some homes.
Doug Wilson Crescent resident Owen Carson said he had lived in the street for eight years and Saturday was the fourth time his property had suffered stormwater damage. However, it was the first occasion water had entered his house.
Fairfax Media reported one man was forced to cling to a bridge on River Road in the early hours of Saturday after abandoning his car and trying to walk home in the rising floodwaters.
Kawerau Fire Station station officer Tyrel Katu told Fairfax the man “did the right thing” by getting out of his vehicle, but it wasn’t long before he had had to call for help.
“He had his cellphone in his hand and was able to call for help while clinging on [to the bridge].”
“If he let go he would have ended up under the bridge. The water was very swift,” he said.
Valley Road resident Dave Mitchell said he woke to the sound of water at 4am and decided to investigate. When he put his feet on the carpet it was wet from water that had flowed inside his house – for the first time in the 30 years he and his wife Kate had lived there.
When a torrent flowed into Doug Wilson Crescent resident Bill Turnbull’s house it thrust a garden shed eight metres from its position near a boundary fence up against the side of his house.
He said residents “knew” the stormwater measures Kawerau District Council put in place above their properties were inadequate so they had complained. The council reacted by deepening a drain intercepting stormwater flows off farmland above, and raised a bund on the bottom side of it, but that effort still failed.
“Whoever did the calculations needs to go back to high school and learn how to calculate water flows better,” Mr Turnbull said.Stormwater had inundated his home twice in 12 months, he said.
Mayor Malcolm Campbell told residents and the Beacon as the rain pelted down on Saturday morning that the stormwater system had been unable to cope with the extreme rainfall.
Sue Edwards said over a 24-hour period her gauge in Doug Wilson Crescent recorded 470mm and another resident in the street measured 450mm.
Retired plumber and drain layer Bill Johnston, who lives on the corner of Doug Wilson Crescent and Beattie Road, said he had told the council the stormwater measures in place above the two streets were inadequate.
“I said ‘it’s not big enough; it’s not going to handle it’.
The floor in his garage and everything on it was soaked, but “thankfully” his house was on piles and the water flowed under and not through it.
Mr Mitchell said a lot of Kawerau families were affected by the flash flooding and there had been a gathering on the street outside his house at 5am to make sure neighbours were fine.
Mr Campbell said there had been “a couple” of big rainfall events in the past, when water in the central business district reached right up to the shops on the promenade, but he had never seen so much in such a short space of time before. His straining household guttering had woken him at 3am.
He said he knew of a car pushed sideways in its garage by flood waters, and cars in a Blundell Avenue basement garage were flooded.
On the issues faced by Doug Wilson Crescent resident, Mr Campbell said what worried him was that if the council put in an even larger bund to prevent flooding and it failed it could act like a breaching dam and “we could have a real big problem”.
Council operations and services manager Tom McDowall said he had been advised that rainfall “slightly in excess” of 300mm fell from 3pm on Friday till about noon on Saturday.
“People who have lived here for 60 years are saying they haven’t seen anything like that before.”
He said he understood stormwater flooded about 10 homes but damage to council infrastructure was relatively minor. There was a slip under some steps and scouring around some stormwater pipes.
He said based on a tour of the damage there were some measures the council would consider to counter similar future events, but these options were still “embryotic” and he would not discuss them until the council and engineers had considered them.