After the worst floods in decades Westport residents mull over options for new defences

Sunday, 15 August 2021

Westport residents have been presented with two costly options for future flood protection.

The West Coast Regional Council has released its 10-year plan for consultation and includes flood walls and stop banks to protect Westport from the Buller and Orowaiti rivers.

The options were in the planning stages when the town was inundated with floods on July 17 and 18 that forced more than 2000 of its 4500-odd residents to evacuate.

A state of emergency lasted three weeks and 70 homes were left red-stickered while another 393 homes were yellow-stickered, forcing residents to stay away from homes that were unsafe.

**READ MORE:

* Data will help predict severity of future flooding - and how to mitigate it

* West Coast flood: Westport ratepayers baulked at $10m protection scheme in 2017

* Westport needs flood protection scheme, regional council chair says

* Westport's 'sleeping giant' - a town with a century to move away from the Buller River

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Flood flows on the Buller River at the time were the largest of any New Zealand river in almost 100 years.

The regional council’s proposals include a $3.4 million option that is preferred by the council, which includes building a floodwall along the Buller River at Westport, stop banks along theKawaitiri River Trail and east to the channel that overflows into the Orowaiti River, which burst its banks in July and caused flooding.

That option would cost $25.93 per $100,000 of capital value a year.

A second $10.2m option – preferred by the council’s river engineers – includes stop bank and flood wall protection around the whole town, including the Orowaiti Lagoon and Snodgrass Rd, which has been flooded twice in three years.

It would cost $77.78 per $100,000 of capital value a year.

Both options included a raised bund to protect the Carters Beach area.

Maintenance and insurance costs are currently unclear, the council said.

“The choices we have made on where we live and do business have made us susceptible to the impacts of natural hazards.

“We need to adapt, or defend as required, to protect the economic, social and cultural wellbeing of our communities.”

Buller mayor Jamie Cleine said it was complex and would take some time to consider, but doing nothing was not an option.

“Clearly there are a number of options to reduce flood risk – flood walls, raising building platforms, [and] relocation are all possibilities, and I think it highly likely a mixture of these options will be used,” he said.

Buller District Council has employed hazard expert Nick Rogers to provide independent advice on the proposals.

He said there was a big job in front of the community as it recovered from the July floods, and part of that was understanding what happened and planning for the future.

Regional council chairman Allan Birchfield said the proposals would protect the town in the event of a one-in-100 year flood.

“The Buller River has the largest flood flow of any river in New Zealand, yet Westport currently has very limited flood protection,” he said.

Work would be funded by a 25-year loan and serviced by a targeted rate on local ratepayers.

Councillors from the district and regional councils met on Thursday to review the hydrology collated by Niwa – which confirmed the July flood as a one-in-60 year event – and flood modelling data prepared by Land River Sea Consulting.

The regional council will hold a drop-in session for Westport ratepayers on August 26.

The council’s long-term plan 2021-31 includes a general rates increase of 30 per cent in the first year, then 10 per cent each year for the next two years.

“Nothing is finalised yet, and we’re urging everyone on the West Coast to consider the issues and proposals and let us know what they think,” Birchfield said.

Submissions close on September 8, followed by a public hearing a week later.