Dargaville's CBD has flooded on previous occasions. File pic Photo: LDR / Northern Advocate
Dargaville businesses are hurriedly sandbagging their premises amidst growing flooding fears as Cyclone Gabrielle's prevailing winds swing round to the south-west.
Kaipara Mayor Craig Jepson said people in the town centre were this afternoon full on sandbagging their businesses ahead of this evening's high tide.
"It's looking pretty challenging here already," Jepson said, on a visit to the town from Mangawhai.
"The water's already just below the stopbanks [between the town and the Northern Wairoa River] and it's still an hour until high tide."
Sandbagging underway in Dargaville on Monday. Photo: LDR / Northern Advocate
Kaipara District Council (KDC) interim chief executive Jason Marris said the council was keeping a very close eye on what happened to river and harbour water levels when Cyclone Gabrielle's currently easterly quarter winds shifted round to the south-west. This was predicted to begin happening overnight.
The cyclone was moving south and would be just past Great Barrier Island tonight then head south towards Coromandel. The shift to the south-west would happen with that southward journey.
Follow RNZ's live updates on the cyclone
Marris said the shift changed things for Dargaville which had so far got off reasonably well compared with impacts in other parts of Northland.
"The south -west wind creates a tidal surge across the harbour, pushing water back up towards Dargaville," Marris said.
Tonight's high tide would be followed by another at 5am on Tuesday.
Jepson said the tidal surge was expected to push up Northern Wairoa River and harbour sea levels by one metre on top of whatever else was going on.
The Northern Wairoa River flows past Dargaville. Photo: LDR / Northern Advocate / Tania Whyte
KDC set up a civil defence emergency operations centre in Mangawhai during the weekend which in turn on Sunday established a remote incident management team for Dargaville that today became a hands-on team on the ground, working out of the council's Dargaville office. Council staff were out in the community providing welfare assistance, clearing debris and trees from roads and unblocking drains.
KDC was liaising closely with the Northland Civil Defence Emergency Management at a regional level.
Dargaville flooding fears due to the cyclone's wind direction change were being further compounded by the fact that the town is positioned on the Northern Wairoa River - New Zealand's longest river - which plays a major role in draining floodwaters from Kaipara Harbour's giant catchment into the sea. The harbour drains two-thirds of Northland, a huge chunk of this flowing out to sea past Dargaville.
Floodwaters from Kaipara Harbour's furthest catchment reaches starting in the eastern ranges between Whangārei and Kawakawa have already started their seaward journey from places such as the top of Helena Bay Hill, Towai, Whananaki and move through the Hikurangi Swamp and out into the Northern Wairoa.
These floodwaters are expected to arrive alongside Dargaville in the next two days.
Hikurangi Swamp's 5200 hectares were already starting to flood this morning with swamp farmers reporting it heading towards stopbank limits with spillways kicking in. Farmers were moving stock to higher ground with some farms already under water.
Cr Gordon Lambeth, who is also the KDC representative on the Northland Emergency Management Group, said the council was working closely with Northland Regional Council (NRC) to monitor what was coming towards Dargaville.
KDC's incident management team is visited by Kaipara Mayor Craig Jepson (right foreground) along with (from left) Cr Gordon Lambeth and Deputy Mayor Jonathan Larsen with incident team members Brian Armstrong and Amanda Bennett. Team member Linda Osborne sits beside the mayor. Photo: Northern Advocate / supplied
Marris said on Sunday Dargaville and Kaipara's west had fared reasonably well in the cyclone. There had been pockets of impact with a couple of outer Dargaville families moved to safer accommodation.
Jepson and Deputy Mayor Jonathan Larsen today visited Dargaville to check out how the council's Civil Defence work was progressing in the west.
Jepson said the situation on Kaipara's east coast was one of extreme 'life-threatening' Cyclone Bola-type winds and huge seas.
"The winds from Cyclone Gabrielle remind me of Cyclone Bola, which I experienced," Jepson said of Gabrielle's 1988 predecessor that hit Northland hard with winds up to 165km/hr.
He said Mangawhai residents should not put out their rubbish or recycling until further notice, due to the cyclone.
Marris said KDC had Civil Defence evacuation centres at the ready for if and when they were needed. At the time of this story being filed that had not been the case. The community would be informed, should an evacuation centre swing into gear. He said Kaipara's Te Roroa had offered marae as evacuation centres if needed.
Jepson said publishing the location of evacuation centres before they were to be potentially used risked sending people to a centre that needed to be moved due to flooding or other issues.
KDC had set up its emergency operations centre ahead of Northland's state of emergency declaration on Sunday so was well prepared.
Jepson said some council services had been affected by the weather. KDC's Dargaville and Managawhai offices were closed today.
He said Kaipara's people should stay home if they could.
"It is your safest place unless you are in danger. [If you are in danger call 111]," Jepson said.
A welfare assistance number had been set up for those in Kaipara affected by the cyclone. Those needing welfare assistance could call 09 439 1111.
Road closures could be found on KDC's website, Jepson said.
People should report roading damage and other impacts via the council's service centre 0800 727 059.
"Be careful, hunker down," Jepson said.
"There are lots of slips and trees down along with power outages. Look after yourselves. Stay put."
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air