A Core Logic report shows coastal erosion will damage Busselton properties into the millions

Risk: Coastal erosion along Geographe Bay is expected to worsen in the coming decades. Picture: File Image.
Risk: Coastal erosion along Geographe Bay is expected to worsen in the coming decades. Picture: File Image.

A new study has estimated that coastal erosion and flooding will damage property worth $335 million in areas across Busselton and Dunsborough in the next 30-60 years.

The paper by property analyst Core Logic, showed that Dunsborough, West Busselton and Broadwater were among the top five WA suburbs with the highest estimated total property value at risk to coastal erosion.

The data predicted that across the three suburbs, 259 individual homes are at risk of 'significant' damage caused by coastal erosion or storm surges in the next 30 - 60 years.

The paper, published in March, also found that Broadwater had the fifth highest coastline retreat rate in Australia, retreating at an average rate of five metres per year.

To mitigate hazards along some areas of the coast, a draft coastal management plan is expected to go before the City of Busselton council in June.

City director of planning and development services Paul Needham said while "significant" areas of the City were subject to hazards, the Draft Coastal Hazard Risk Management and Adaption Plan (CHRMAP) proposes a "fairly comprehensive and strategic approach to mitigating the hazards, through proactive management of the coast."

The draft plan outlines a strategy for the city to protect coastal areas over the next 100 years, and breaks the coastline into 19 management areas.

The strategy outlines whether the city should protect or retreat from the coastal areas, and doesn't include guarantees that landowners in Siesta Park or Marybrook will be protected past 2070.

The City received more than 80 formal submissions and 60 individual public submissions on the draft plan last year, which Mr Needham said showed "broad support" for the proposed long-term coastal management for most of the coast, except for the Siesta Park and Marybrook areas.

"The City has now had several fruitful meetings with a group that has been formed to represent the views and interests of landowners in the Siesta Park and Marybrook areas, with a view to identifying alternative approaches to long-term coastal management in that section of the coast," Mr Needham said.

UWA coastal oceanography professor Charitha Pattiaratchi said the local community was already aware that many of the coastal properties could be damaged by coastal flooding in coming decades.

"Most of the people who live there accept that that is going to happen. It's not a surprise," he said.

"The cost of building a sea wall is going to be prohibitive. It's more than what the properties are worth, because it's a long coast line."

"They could charge everyone ten times their rates and build coastal protection, [but] you're talking about a prohibitive amount of money. It's not about what you can do, but whose going to pay for it."

"I consider Busselton to be one of the most vulnerable coast lines in the longer term in Western Australia, and to a lesser extent, Bunbury."

Mr Pattiaratchi said other coastal communities around the globe have faced similar events, and moved away from coast lines.

"We have to learn as a community globally, that we have to change our ways. We cannot live next to the ocean."

Busselton SES local manager Wayne Credaro said the SES had continual discussions about what flooding might look like, how to go about mitigation and updating flood plans.

"We make our community aware that times are changing," Mr Credaro said.

"We understand our flooding risk yearly, as it changes each time. That's what we'll adapt to."

"We look strongly at historical data. We know what our ten year and five year floods look like, so we can understand what our next five years will look like, or what our next ten years may look like."

"There's monitoring stations on most of the rivers around here. There's work being done all the time on what flood's are going to look like. We're getting better and better at it."

"Busselton's always been at risk for the past 50 years, but that risk is getting less, because we have better knowledge on how to prevent that."