A FLOOD strategy flowchart has been blamed for conflicting evidence from Wivenhoe Dam engineers on how they managed Brisbane flooding in January, 2011.
The Crime and Misconduct Commission has exonerated the three flood engineers who were investigated after their conduct was questioned during the Queensland Floods Commission of Inquiry.
John Tibaldi, Robert Ayre and Terry Malone were responsible for releasing water into Brisbane's waterways during the Wivenhoe Dam crisis at the height of the Brisbane flooding.
The watchdog found there was "no evidence to suggest the conduct of the engineers evidences offences against the Criminal Code or official misconduct".
Retired appeal court Judge John Jerrard found there was not enough evidence to launch a full investigation into allegations they had conspired to produce a false report and misled the inquiry about their actions.
He, instead, focused on how the engineers articulated what they had done after the event in reports and oral evidence to see if charges such as perjury were appropriate.
Mr Jerrard found an inherent contradiction existed between the manual's flood strategy flowchart and a definition of one of the strategies.
"If the engineers had been following the flowchart they could have honestly believed they were in Strategy W2 until the contradictory terms of the definition were adverted to," he concluded.
"This contradiction in the manual would provide an explanation for all of the engineers' inconsistent statements and descriptions of what they had done at the time of the January 2011 flood event, and is not evidence of either the commission of a criminal offence or official misconduct."
Mr Jerrard noted the Queensland Flood Commission of Inquiry's recommendations for Seqwater to review or create a new manual, with help from experts such as technical writers and legal reviewers, to ensure compliance during any future flood.
He said implementing this recommendation should remove any inconsistency or ambiguity.
This comes a month after an Engineers Australia report also backed the technical competence of engineers after a comprehensive analysis of the inquiry's final report.
Senior engineers and flood-experts from Engineers Australia's Queensland Division Flood Committee found the dam operators performed appropriately "given the circumstances".
They argued, though, that there needed to be a consistent approach throughout Queensland and Australia to mitigate damage in such situations.
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