Cornish St counts cost of flooding
BIG CLEAN-UP
Partially blocked culverts in Cornish St may have made worse the serious flooding on May 14, but the regional council points the finger at property owners.
The Hutt News visited commercial premises on the street off State Highway 2 just north of the Petone overbridge on May 20 and some were still hosing out silt and muck.
Hardest hit was Contherm Scientific at the western end of the street. The manufacturer and exporter of laboratory incubators and ovens may be months away from getting back to full production.
Owner Robin Reynolds says that with so much expensive equipment ruined, the cost could blow out past $2 million, and that does not count the potential for lost orders while they wait for specialist replacement machinery to be built and shipped.
‘‘ It’s a serious business this whole thing. People aren’t going to wait [while we get back on our feet].’’
All of the business owners we spoke to acknowledged Mother Nature was in a frenzy that Thursday, with nearly 50 millimetres of rain dumped on the city between 11am and noon alone.
But Reynolds points to culverts running under buildings on the northern side of Cornish St, there to allow Korokoro Stream to flow on its way to the harbour. The culverts looked to be partially choked by mud, gravel and weed build-up.
‘‘Without blaming anybody, because that’s when people scramble for cover . . . but on the day the stream was flowing heavy but it was coping.
‘‘But it reached the point where the culverts couldn’t cope with the capacity . . . You’ve got [water] flying at 20 or 30kmh and it can’t go anywhere. [It was backed up and] we were flooded out in 10 minutes. It came down both sides of the building, and then on down the rest of the street.’’
Reynolds said the Contherm factory was inundated with water up to a metre deep. Expensive gear will have to be written off; sheet metal and other products have been contaminated; shrinkwrapped incubators and ovens ready to go out to clients will need to be inspected for damage.
‘‘I’m amazed at how much mud was in the water – I’d say it was 20 per cent mud.’’
In past years a drott (a type of bladed tractor) or Bobcat would clear out the culverts but Reynolds says he has not seen any such maintenance in the stream bed by the culverts for years.
‘‘In my mind it’s a clear case of somebody needing to put up their hand and say ‘we should have done that’.’’
Greater Wellington Regional Council flood protection manager Graeme Campbell says the culverts are the responsibility of the owners of the buildings built on top of them. Years ago GWRC did carry out clearing work but it is noted on encumbrances on property titles that clearing the culverts is the owners’ responsibility.
‘‘Whether they’ve kept up to date, or whether they’ve known about that as properties have changed hands . . . well, they should know because it’s on the titles.’’
Further downstream, land is owned by the NZ Transport Agency (SH2), KiwiRail and Hutt City Council and they also have culverts to keep clear.
Campbell was pleased businesses had acknowledged rainfall of May 14’s level was rare. The Korokoro Stream culverts have a flood capacity of perhaps a 5-year return period; the council’s best estimate was the May 14 flow was of a level that on average would happen only once every 20 years.
‘‘Certainly the 1976 storm was much worse.’’
Concerns were raised after the Workers at Ullrich Aluminium were amazed how quickly Cornish St was turned into a river on May 14, production manager Steve Eastall said.
The plant lost 31⁄ days of production due to cleaning out a layer of mud that was 75 millimetres thick in places. ‘‘Everybody along the street was helping each other out, sharing squeegees and so on.’’
With stock contaminated and other damage, Eastall estimated the insurance bill might reach $400,000.
Next door at National Auto Glass Supplies, there was a muddy tide line of half a metre up the stacks of windscreens.
Kevin van der Merwe, down from Auckland to help the local staff clean up, said walls had to be cut out to help with drying, and thousands of screens and windows worth a couple of hundred dollars each would be written off. 1976 flood about damage but with up to 14 land owners, sorting out who needed to do what may have been abandoned as too complicated.
‘‘It was quite expensive and it needed everybody to line up all their budgets.’’
The regional council installed a debris arrestor further up Korokoro Stream and on May 14 ‘‘that stopped a huge amount of logs and other stuff coming down...but with that level of flow, it’s going to be overtopped’’, Campbell said.
The council also extracts gravel and other build-up at the stream mouth where it enters the harbour.
Campbell said GWRC was meeting the NZ Transport Agency over the flooding issue and was willing to help co- ordinate a response by other property owners. ‘‘ But it’s not a simple issue.’’
Many of the buildings on Cornish St may be gone in four or five years anyway, swallowed by the new Petone raised roundabout/ interchange to be built as part of the Petone-Grenada link road.