An expert in natural hazard planning says the government needs to buy out residents in flood-prone areas such as Anzac Parade in Whanganui, or risk people losing their lives.
In 2015, floodwaters forced 250 people to be evacuated from their homes in thecity and climate change is expected to increase the frequency and intensity of such weather events.
Professor Bruce Glavovic of Massey University has been working with the district and regional council on flood planning.
He has been facilitating flood resilience workshops with Anzac Parade residents, and he has had little good news to share with them.
"The long story short in this particular case is that this river is going to flood again. It's going to flood seriously and those floods are likely to increase in magnitude and possibly even frequency in the coming decades, so the risk is not going to go away."
Dr Glavovic looked at raising stopbanks and lifting houses on Anzac Parade - both of which were technically challenging and expensive.
Raising stopbanks to protect against a 1 in 200-year flood would cost about $30 million, while lifting a typical home would cost between $300,00 and $500,000 - or close to market value on Anzac Parade.
Dr Glavovic said the short-term focus should be on efficient evacuation.
"The first thing that has to happen is we need a really effective warning system that gets to everybody, so they can make wise decisions and evacuate if necessary.
"My worry is that failing to do that will lead to loss of life sooner or later."
Long term a buyout of the 50 most flood-prone houses was necessary - estimated to cost about $28 million.
Dr Glavovic said that would require government intervention.
"Government needs to step-in in cases where there are communities in harms way and where there is a serious risk of loss of life and where people are unable to choose alternatives."
Wayne and Kisa Coles. Photo / RNZ
He said there needed to be a process for the equitable sharing of the costs with vulnerable communities such as that on Anzac Parade.
Floodwaters reached head-height in Kisa Coles' home in 2015.
She had hoped for more from the planning workshops.
"It's just the same. No solution really, but at least they are trying."
She welcomed the focus on an early warning system.
"We weren't told until 10pm at night forcefully to get out of the house.
"So, I don't know where the break up is in that department because in town ... a cafe at the bottom of town told me they were warned at 12 o'clock in the afternoon."
Barbara Jellyman was at the workshop supporting her father Trevor.
"A lot of people won't move there unless the government makes it mandatory and funds it to a certain extent otherwise I don't think you're going to get a real solution."
The Massey University team will share its findings with the wider Whanganui community at a public meeting next month.
It will then make its recommendations to local authorities.
