THE clearest official acknowledgment that the devastating flood in the Brisbane River was avoidable has been the decision yesterday to let go 25 per cent of the water stored in the Wivenhoe Dam.
In ruling that about 300,000 megalitres will be released, the Queensland government is sensibly backflipping on an outdated policy that should have been junked last year. The action is tantamount to admitting the administration got it wrong.
Never mind the spin.
Those 300,000Ml would have made a huge difference last month. It could make a similarly significant difference if Brisbane gets another major rain-dump this wet season.
Calculations by senior engineers who are closely studying the dam show most of the flooding that damaged tens of thousands of homes would not have occurred if the extra capacity for flood storage had been available last month.
Serious policy shortcomings, added to the tardiness of the dam operator, SEQWater, before it was forced to make huge and sudden releases of water on January 11 that flooded Brisbane 36 hours later, should be investigated by the commission of inquiry into the floods.
As more admissions and facts emerge in coming weeks, many Queenslanders in the state's southeast may realise they have been let down by experts paid handsomely to know better.
The policy to keep the dam at its 100 per cent or full supply level of 1,165,000ML was logical during the drought linked to El Nino. Brisbane had few rainfall events in the El Nino years, and water was a precious commodity.
But emphatic confirmation last year of one of the most intense La Nina phases ever, with serious warnings of flooding rains, should have alerted the hydrologists and their political masters to the grave risks of running the dam as if it were still in the grip of drought.
One of the spurious lines of spin being run now is that the risks are "easy to see in hindsight".
It is a line that should be condemned by everyone who put faith in senior public servants to do the obvious: keep an eye on the weather, change the policy settings when the circumstances change fundamentally, and operate the Wivenhoe Dam safely and responsibly.
The risks might not have concerned SEQWater until now, but the risks were well understood by residents of the towns of Fernvale and Lowood, close to the dam in the Brisbane Valley.
They pleaded with SEQWater last year to do precisely what is being done now.
The residents were told the dam levels would not be lowered, and that they would not understand anyway.