NSW Supreme Court Justice Robert Beech-Jones found in favour of about 6870 claimants after accepting that engineers responsible for flood operations at Wivenhoe and Somerset dams were negligent and breached their duty of care.
Nearly 7,000 Queenslanders have won a class action over the state's devastating 2011 floods, with a judge finding they were victims of negligence.
Justice Beech-Jones said the main argument in the class action was that calculations regarding the release of water from the Wivenhoe Dam were based "on the level of water in the dam and not the amount of rain forecast".
IT'S been nearly nine years since Queensland retiree Frank Beaumont watched floodwaters swallow his home west of Brisbane.
Shirtless and wearing the same old trousers he had on when his Goodna home went under, the 77-year-old admits to being surprised by his own tears on learning he'd won. "We've had so many trodden down moments where the insurance didn't pay, being kicked out of a rental home and then having to rebuild an absolutely devastated house".
The dam engineers' mistakes derived from "a failure of approach, specifically a failure to follow the very manual they drafted 18 months earlier", according to Justice Beech-Jones.
Justice Beech-Jones agreed engineers negligently managed the dams.
He found that during days of heavy rain, before the peak of the flood on 11 January, dam engineers prioritised keeping downstream bridges open over trying to limit flooding in urban areas.
The focus from the state government should be on securing timely compensation, and on making sure Queenslanders were never again at the mercy of mismanaged dams, Ms Gilsenan said.
Justice Beech-Jones told the court numerous decisions made by dam engineers bore little reference to the instructions outlined in the operations manual.
The group of over 6000 flood victims have won the largest class action in Australian history after the floods devastated large parts of Queensland and killed 33 people.