Queensland’s Paradise Dam to be abandoned, replaced

After more than four years of work on a $1.2bn repair, Queensland’s Paradise Dam will be abandoned and replaced because construction defects are so bad.

Testing by the Paradise Dam operator, state-owned SunWater, has found that the ‘existing dam wall has too many issues to be repaired’.

Queensland’s Paradise Dam, built by the Beattie Labor government less than 20 years ago to irrigate one of Australia’s most productive food bowls, will be abandoned and replaced with a new dam because construction defects are so bad.

After more than four years of work on a $1.2bn joint state-federal government repair of the 300,000 megalitre dam, near Bundaberg, new tests show that concrete in the once-52m high wall is so degraded it will be a ­future safety risk to the local population.

The dam, opened in 2006 and constructed under a then-lauded private public partnership set-up by the state government, was found to be riddled with design and structural problems in 2019.

The wall was lowered by 5m for the repair, cutting its original storage capacity to 42 per cent, amid fears it could break apart if the dam was filled in an extreme weather event.

But now testing by the dam operator, state-owned SunWater, has found that the “existing dam wall has too many issues to be repaired’’.

The state Labor government, which was initially secretive about the defects when it first released 105,000 megalitres of water during a drought to mitigate the safety risk in 2019, is now planning to build a new wall about 70m downstream from the existing dam.

An announcement will be made on Thursday but the government won’t say how much the new dam will cost or when construction will begin, with engineering and environmental approvals expected to take more than a year.

Queensland Water minister Glenn Butcher told The Australian it was too early to put an estimate on the cost of the new dam but that it will “be way north of the $1.2 billion we have for the repair”.

“There have been international experts working on this and the conclusion is that we have to build a whole new dam rather than build on the top of the existing wall,” he said.

“From what we have been told it is a shit-heap, you wouldn’t put anything on the top of it.

“The composite of the concrete isn’t up to scratch and if water gets in, it gets worse.”

Built at a cost of $200m, it was the first “roller-compacted concrete dam” in Australia, which involves placing 310mm thick horizontal layers of concrete on top of each other.

A commission of inquiry was ordered in 2020 by then Premier Annastacia Palaszczuk after The Australian revealed that SunWater officials and senior bureaucrats had been aware for years that there were design problems with the dam’s “dissipater” and that layers of concrete in the spillway wall had not properly ­bonded.

Documents showed serious structural problems were identified within a year of the dam’s opening and that the structure had been severely damaged in the 2011 and 2013 floods that hit the region.

Annastacia Palaszczuk at Paradise Dam in 2022. Picture: Paul Beutel

The inquiry found the dam was “well below” safety standards, with expert advice warning it would have been unlikely to withstand a repeat of the 2013 floods and could have broken-up if the storage capacity was not lowered in 2019.

“The current strength of the Paradise Dam spillway is calcul­ated to be well below safety guidelines, and the life safety risk is also calculated to be well above the guidelines’ limit for what society is expected to tolerate if there was a failure,’’ then-acting Inspector-General of Emergency Management Alistair Dawson said in his report to the inquiry.

An estimated 40,000 people live downstream from the dam and in the projected path of debris and water from a catastrophic failure of the dam.

In a statement, SunWater chief executive Glenn Stockton said the safety of the local population had been ensured with the lowering of the dam wall buy that it could not be repaired.

“Paradise Dam’s safety was ensured following the lowering of its wall, ensuring safe operation for many years to come,’’ he said.

“However, the concrete quality of the dam means it cannot be repaired to last the many decades we expect from these assets.”

The government, which faces an election in October, this year says the new dam will hold the same 300,000ml capacity of the Paradise Dam.

“Reliable water supply is critical to jobs, growth and liveability in regional Queensland,’’ Mr ­Butcher said.

“That is why we remain committed to restoring the full water supply for the people and industries of the region.”

Federal Nationals MP Keith Pitt said Paradise Dam was “the biggest public infrastructure failure in Australia’s history”.

“Labor’s Paradise Dam disaster just keeps getting worse,’’ he said.

“First they build it to a price not a standard, then they knock the dam wall down and reduce its capacity and now they can’t even repair it because it is poorly constructed.

“How long will it take to simply secure a new environmental approval, no matter the time and cost to build the dam and deliver critical water to our region.

“Labor’s incompetence never seems to end and the people of our region will pay the price.’’