EXPLAINED: Why at-capacity Wivenhoe Dam not a threat

Releases from Wivenhoe a decade ago were blamed for contributing greatly to the flooding that inundated Brisbane and other parts of the South East in 2011. This is what is different this time around.

Wivenhoe Dam is standing firm against fears of a repeat of the 2011 floods which devastated South East Queensland.

The dam’s storage can take millions more megalitres of water before any repeat of the catastrophe of the floods still fresh in the minds of South East Queensland residents.

Releases from Wivenhoe a decade ago were blamed for contributing greatly to the flooding that inundated Brisbane and other parts of the South East in 2011.

However, Graham Fraine, director-general of the department of water, said the current storage capacity of Wivenhoe meant there was no immediate threat of a repeat of that disaster, despite the grid’s main dam jumping from about 60 per cent to 100 per cent of capacity in a matter of days.

Water flowing over the spillway at Wivenhoe Dam. Picture: Contributed

“For those interested in how that compares to the 2011 event, there is a lot more, in fact about two million megalitres more of supply that this dam can take at this point in time,” he said.

“There were some releases from Wivenhoe during the course of last evening and they were done at the time to do some strategic releases in order to manage water flow levels between the various parts of the SEQ network.

“Future releases will be looked at through the lens of the flood manuals that SEQ water operates by and through the lens of when rain and water levels subside.”

SEQ Water Chief Operating Officer Stuart Cassie said modelling showed Wivenhoe should be able to cope with the extra floodwaters without posing a risk to communities downstream.

“The current modelling that we’re using in conjunction with the BOM is not predicting that that capacity will be filled up,” he said.

“We’re playing a balancing act in terms of making sure that we’re not increasing the flows downstream unnecessarily so we will wait for the rains to subside and the flows in the rivers to subside and that’s the point that we will release water in accordance with the flood manuals.”