4BC News: Queensland's Wivenhoe dam was negligently operated during the 2011 floods and that caused widespread, unnecessary damage, a litigation funder has found.
IMF Australia says its own investigations had determined the dam was not operated competently, and as a direct result downstream properties suffered unnecessary flooding.
IMF Australia executive director John Walker on Monday told AAP he was now extremely confident that a class action by flood victims would proceed.
Investigations had determined the dam "was not operated to the standard expected of a reasonably competently dam operator in all of the circumstances", IMF Australia said.
It said independent US experts engaged to carry out the investigation had identified two key failures:
- a failure to use rainfall forecasts in making decisions about (dam) operating strategies; and
- a failure to preserve a reasonable amount of Wivenhoe's storage capacity to provide optimum protection of urbanised areas from inundation.
In a release to the Australian Securities Exchange on Monday, IMF Australia said:
"Based on these investigations, IMF has formed an opinion that material flooding of a large number of properties down river from the Wivenhoe dam would not have occurred had Wivenhoe been operated during the flood event to the standard expected of a reasonably competent dam operator in all of the circumstances."
Mr Walker said the investigation's findings marked the end of the due diligence process for the class action being pursued by the law firm Maurice Blackburn.
He said the next stage was to formally establish the level of loss among affected residents, and if there was sufficient interest to proceed with the class action.
But Mr Walker said he was extremely confident it would go ahead.
He said 2000 flood victims were already on board, and 2000 others had expressed an interest.
The next step will be contacting all residents in areas the IMF investigation identified as having suffered unnecessary flooding.
"We'll be writing to all of the flood-affected people who we think have a claim," he told AAP.
"A lot of those people are already involved. But there's a lot who either have not been aware, or haven't decided what they want to do."
He said he could not provide an exact figure for the number of properties IMF believed had suffered unnecessary flooding.
But he said maps of affected areas, "all along the river", would be released at a press conference in Brisbane at 11am (AEST) on Monday.
"We're currently in the process of using Google technology and maps ... to identify how many there are.
"But the state knows how many there are, and certain instrumentalities know how many there are."
In March last year, Queensland's floods inquiry found Wivenhoe dam operator - the government-owned SEQwater - breached the dam's operating manual during devastating floods in Brisbane, Ipswich and surrounds in January 2011.
Commissioner Catherine Holmes found the dam was operated in breach of its manual from 8am on January 8 until the evening of January 9, before Brisbane and Ipswich flooded.
But she also noted the manual was "ambiguous, unclear and difficult to use, and was not based on the best, most current research and information".
She found flooding in Brisbane and Ipswich could have been reduced to some degree, if capacity in the dam had been freed up before the December deluge that contributed to the floods.
Ms Holmes also found there was evidence three dam engineers had colluded to mislead the inquiry about how they managed the dam during the flood crisis.
But the corruption watchdog, the Crime and Misconduct Commission (CMC), later exonerated the engineers of misleading the inquiry.
The CMC agreed that the dam was operated in breach of its manual.
But it found ambiguities in the document explained the engineers' inconsistent statements and descriptions of what they did during the flood crisis.
However the CMC was only asked to look at documents the engineers prepared about their actions and their oral testimony to the inquiry.
It did not look at whether their management of the dam's gates during the flood crisis could amount to a criminal offence or official misconduct.
IMF Australia and Maurice Blackburn contend that too much water was allowed to accumulate in Wivenhoe, and the strategy for water releases during the crisis was botched.
Maurice Blackburn has previously said any class action against the Queensland government would probably seek compensation in excess of $1 billion.