Cliff collapses near Robe lighthouse as SA coastal erosion worsens

Australia Broadcast Center

a day ago

A coastal South Australian council says it has its hands full with the impacts of erosion, after at least 10 metres of cliff near Robe's working lighthouse collapsed at the weekend.
Large amounts of rock and vegetation along a cliff to the west of the town in the state's south-east collapsed late on Saturday.
The District Council of Robe has since closed a nearby car park and barricaded the area, which is also near a scenic coastal walk.
The collapse comes less than a month after Robe's jetty was destroyed during severe storms, and with the town's iconic obelisk also at risk of falling into the sea.
Council chief executive Nat Traeger said the collapse also exposed significant undercutting of the cliff above.
Ms Traeger said the incident highlighted the rapidly increasing risk erosion presented to the town's infrastructure.
"Our coastal adaptation strategy did indicate the area around the lighthouse was vulnerable, but we probably weren't expecting that to go so quickly," she said.
"We've been dealing with the coastal erosion around Fox and Hooper [beaches], and that's been taking up our attention."
The council plans to use a drone to examine the collapse further.
The collapse of the limestone cliffs along Robe's coast is not uncommon, with a large hole opening up further along the coastal walk, between the lighthouse and the obelisk, in 2022.
Ms Traeger said the Commonwealth-managed lighthouse was not in immediate risk, but it heightened concerns about the 170-year-old obelisk.
"[The obelisk working group] was talking about having a worldwide lottery as to the date it may fall," she said.
"The lottery may switch to which one goes first, the lighthouse or the obelisk, because they're both now significantly vulnerable.
"We've certainly got our hands full at the moment."
Robe Obelisk Working Party member Doug Fotheringham looked at survey data of the Robe coastline from 1896 and compared that to data from 2009, finding some sections had eroded as much as 26 metres during that time.
He said cliff collapses along that part of the coast were expected, particularly after storms.
"At the time in 2009, we recommended that they basically don't put any assets within 30m of the cliff line," Mr Fotheringham said.
"You get debris building up at the base of the cliff after a cliff fall, and that actually protects the cliff from further erosion.
He said the lighthouse had a "bit more of a buffer" than the obelisk, but may still need to be relocated.
"I wouldn't be surprised to see the obelisk go in my lifetime, but the Robe lighthouse might go in our children's lifetime, and I'm in my 70s," he said.