Uni researchers predict what will happen when Bribie Island splits in two

A combination of this year’s Cyclone Oma, which battered the Queensland coastline in February, and a number of washovers has reduced a section of island to a strip that’s just a few metres wide.

Researchers have previously noted that Bribie Island’s eastern shoreline was eroding at the rate of about a metre a year, with storm surges increasing that to 10 metres a year.

The island is also at risk of rising sea levels brought about by climate change.

Researchers used a special model to look at the growth and more importantly the loss of the island’s shoreline, analysing how it was likely to reshape itself over time.

The model allows researchers to analyse short and long-term processes while taking headlands and sea walls into account, as well as long-shore and cross-shore sediment movement.

“This is useful because at the northern end of the island there are areas of very thin coastline – with climate change and rising sea level, these thin areas of Bribie Island could potentially break through into Pumicestone Passage,” UQ researcher Verity Taylor said.

“A breakthrough of Bribie Island’s northern end would split the island in two, removing some of the national forest along with the flora and fauna that inhabit it, as well as perhaps making it even more prone to erosion.”

Bribie Islands splitting into two would also have a big impact around the island, she said.

“It is important to realise the changes that may affect Golden Beach early so appropriate measures can be put in place to minimise any damage to infrastructure and properties,” Taylor said.

Golden Beach is already protected with groynes and a sand renourishment program.

Authorities have feared a Bribie Island breakthrough for several years now, warning in 2017 that up to four sites on the island risked a broach.

It will potentially mean that the existing channel at the Bribie Island Spit would narrow, with the new broach splitting the island becoming the new main tidal channel.

The Queensland Government protects Bribie Island as a designated recreation area. The erosion and “an inevitable ocean breakthrough” are regarded as a natural event.