'Potentially catastrophic': Westland's Waiho River changing course years ahead of forecasts

Experts say Westland's Waiho River is changing course three or four years earlier than expected, posing a serious threat to people's lives and property in Franz Josef.At a public meeting on Wednesday night an independent technical advisory group called for councils to urgently secure central government funding and prepare for a managed retreat before disaster strikes.The group of river scientists, appointed by the West Coast Regional Council, had previously recommended releasing the river's southern stopbanks within 10 years to allow the Waiho (Waiau) River to fan out naturally.That would submerge local farmland, require the relocation of State Highway 6 and the town's wastewater treatment ponds and lead to the abandonment of the local aerodrome.Group spokesperson Professor Ian Fuller said the rapid river changes meant the timeline had effectively brought that reality forward.Professor Ian Fuller. (File photo)Ian Fuller / SuppliedWithout action there was a "potentially catastrophic" risk to life, he said."It's not just a question of water flowing over the stopbanks. It's a question of water and sediment - coarse debris, essentially gravel - moving across what is currently protected land," he said."I don't think Aotearoa New Zealand can afford a disaster occurring in this area."Fuller stressed that councils would not be able to manage or pay to ward off the threat on their own."This can't be done by the local community or the local or regional council. It has to be addressed at a government level. There has to be central government funding involved," he said.Westland mayor Helen Lash said locals were understandably angry and frustrated to learn that millions spent on river protection work could be undone."I'm not surprised by it because I've been watching it happen, as has all of Franz Josef. They did say some time ago that the river would migrate over to the Tātare [tributary] and it's done just that," she said."The last [technical advisory group] report was done in 2023 and it indicated that with the extension or the expansion of the current stopbanks, that would give us another 10 years. That 10 years has disappeared in three," she said."Bearing in mind that these ratepayers have poured huge sums of money into river protection work, which they're now told might have to be removed to let the river go and take their land. It's a bitter pill to swallow."Lash said she had formed a multi-agency working group, which aimed to have a formal proposal ready for ministers early next year."We don't go to the government and say, 'Look, we need this money, where the hell do we start spending it?' We've got to do the hard graft," she said.Fuller said affected landowners would need to be properly compensated.Authorities needed to move before it was too late, he said."We have the opportunity to act pre-emptively. We have the opportunity to avert any disaster. Action is needed and action is needed urgently," he said.