A river threatening the Franz Josef sewerage ponds has suddenly changed its course - less than a month since another dramatic shift.
About 50 per cent of the Waiho (Waiau) River on the West Coast has returned south, after 95 per cent of the
Waiho River changes course again: Main channel splits below Franz Josef township
Subscribe to listen
Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber? Sign in here
Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
A warning sign for people to stay away from the bed of the dangerous Waiho River, just west of the State Highway 6 bridge at Franz Josef. Photo / Brendon McMahon
AdvertisementAdvertise with NZME.
AdvertisementAdvertise with NZME.
Yesterday, Haddock said he was due to be briefed on that, including how far upstream it was of the bridge.
Waiho Flat resident Richard Molloy said a large portion of the river’s main channel suddenly switched back to the south side late last week.
The braided river bed is known for sudden shifts and raised alarm for the Westland District Council after most of the river swung north close to the Franz Josef sewerage ponds in late January.
Molloy said the latest shift happened overnight Thursday, with the channel splitting about 1km below the State Highway 6 bridge.
AdvertisementAdvertise with NZME.
The latest move did not follow flooding.
Molloy said the river had largely moved away from the Westland District Council Franz Josef sewerage ponds area on the north side as of yesterday.
Council chief executive Darryl Lew could not be reached for comment yesterday, but Haddock said the sudden shift was no surprise.
Read more farming and rural stories on The Country.
“It’s a dynamic braided river,” Haddock said.
He had enlisted a local helicopter operator at the weekend to confirm to him the river’s main channel had split just below Franz Josef township.
About 50 per cent of the flow was south past the Waiho Flat, Milton and Others stopbank, with the rest of the main flow still going north via the Tatare Stream, Haddock said.
Waiho River sediment build-up
Meanwhile, the new Lidar imaging of the river in the gorge upstream of the bridge revealed 1.05 million cubic metres of sediment built up in the past six months, he said.
Haddock said he had an urgent meeting on Friday with Regional Development Minister Shane Jones.
This was also to brief the pending formal approach to Government about plans to abandon Waiho Flat in about 10 years by pulling down the existing stopbanks to let the river flow south.
AdvertisementAdvertise with NZME.
“It’s a dynamic braided river that is carrying a lot of sediment,” he said.
“We stressed that to the minister: it’s a one-off type of river. Long term you can’t continue with that river carrying that much - it will continue to build up.”
Haddock said the huge buildup of sediment needs to go somewhere, but a lack of natural flushing and the barrier of the Waiho Loop glacial moraine were inhibitors.
“The minister did ask if it was an opportunity to dredge the river out.”
Haddock said the many thousands of truck movements needed for such an operation made it impossible to contemplate.
Meanwhile, Molloy criticised the council for being too slow to do urgent maintenance on the Waiho Flat stopbanks while the riverbed had been dry.
AdvertisementAdvertise with NZME.
Molloy said this slow approach caused “the biggest frustration” and he accused council of not knowing “a bloody thing about this river”.
However, Haddock said its engineering team had urgently assessed the south bank stopbanks and they were moving as quickly as possible - including pushing for the release of $8.77 million Kanoa funding set aside for the area.
“I know people are criticising, but they’ve got to do a proper evaluation and for a costing on that work.”
He said he expected the council may see a proposal at a committee meeting today.
- LDR is local body journalism co-funded by RNZ and NZ On Air.
