The Adelaide Hills town of Echunga has been sealed off due to the threat of a 10 megalitre farm dam bursting, with residents evacuating amid warnings that up to 40 properties could be flooded in a worst-case scenario with water hitting homes “like trucks”.
The State Emergency Service issued a flood emergency warning for Echunga shortly before 5.30am on Wednesday due to a “high risk” that a dam wall 500 metres upstream from the Adelaide Hills town will collapse.
The privately-owned dam is located between Marianna Street and Church Hill Road. It is holding about 10 megalitres of water, according to the SA Environment Department – equivalent to 10,000 metric tonnes of water.
Many residents have evacuated to the Echunga Football Club or left town, while roads into the town have been closed.
“A dam is failing in Echunga which will threaten you and your family’s safety,” the SES said in its latest warning issued at 11.30am.
“If you are in this area you should prepare for flooding.
“Move valuables to a safe place. Consider going soon to a safer place if the path is clear.”
About 30 to 40 properties could be “inundated with water” if the dam was to collapse, according to SES incident controller Craig Brassington.
“[The wall] is holding up at the moment … we’re expecting some slippage just because of the reducing of water and that side of things,” said on Wednesday afternoon.
“There are still some people in the area, we’ll be doing another doorknock this afternoon just explaining the risk they are facing.”
Mr Brassington said the dam – estimated to be 35 metres wide and 50 metres long – had not reached capacity since 2016.
“We brought crews in to start pumping, there’s also an excavator down on site putting a channel into the northern side with a spillway to try to reduce the actual water flow,” he said.
“We’ve had pumps in overnight trying to reduce [the water level] – we’ve reduced it by approximately half a metre.
“We need to get something like a metre and a half depth to make it a safe area.”
Mr Brassington said further lowering of the water level could take “up to another 24 hours”.
Among the properties directly in the firing line is Echunga blinds shop Complete Shutters Australia, about 270 metres directly east of the failing dam.
CEO Marc Boord said he had been clearing the property since receiving an evacuation warning at 5.20am and was told by authorities the dam could fail “within 30 minutes or it could be within three days”.
“The dam stretches, from what we can see, the length of our street,” Mr Boord said.
“There’s a creek that runs past the properties on our street at the bottom, and if it does go they’re hoping it’s a slow release and it will go through there.
“If it’s not, it’s obviously going to be a lot worse.
“They’re concerned about A, the volume of water, and B, the debris it could bring with it.”
Asked if he was sandbagging his property, Mr Boord said: “There’s probably no point in us sandbagging because if it’s a controlled release it will go down the creek.”
“If it is a big release and it does breach and it does come down, there’s nothing really we’re going to be able to do here – if we’re in the line we’re in the line.
“The CFS says the houses in the direct path if it does breach all at once, it’d be like trucks coming through the home.
“They pretty much told us a couple of hours ago that it’s going to breach – they just don’t know how and when.”
SES crews worked overnight to mitigate the flooding threat after the dam’s owner notified authorities on Tuesday afternoon about the potential failure.
The SES initially issued a “watch and act” message for Echunga on Tuesday night but upgraded that to a flood emergency warning on Wednesday.
This story first appeared in InDaily and is republished here with permissio
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