Rain, not dam releases, behind current flood
Rising waters empty homes again
People remove belonging from homes ahead of a predicted flood in Enid Street in Ipswich. Photo: Harrison Saragossi
As the water rises and southeast Queenslanders get a sense of deja vu, they're being assured this time the flood has nothing to do with the region's dams.
Despite the Wivenhoe Dam level increasing from 89 per cent to 119 per cent in the space of 24 hours and being expected to reach about 140 per cent by the end of the week, the water released from the dam in the few past days has had little to no impact on flooding.
In 2011 huge dam releases from an almost full Wivenhoe Dam inundated thousands of homes in southeast Queensland but the 2013 flood can be attributed to one simple thing – rain. And lots of it.
Ex-tropical cyclone Oswald was originally expected to dump its 200-300 millimetres of rain on Brisbane and the Sunshine and Gold Coasts.
Instead, it fell west of Brisbane in the catchments which flow into the capital's rivers and creeks.
"The flood that we're seeing right now is primarily, almost totally, due to the floodwaters coming downstream of the Wivenhoe Dam," Premier Campbell Newman told reporters on Monday.
"The Bremer, Lockyer and Laidley rivers and a number of smaller creeks that come all the way down between Wivenhoe and Brisbane CBD - that's what's driving this.
"Wivenhoe is doing its job, Somerset is doing its job."
Bureau of Meteorology hydrologist Andy Barnes agreed.
"Really, it's pretty simple, there's been a lot of rain in the catchments," he said.
"That runs off into the rivers and creeks and eventually works its way to Brisbane.
"Too much water in the channel means the river level rises and you get the floods. It's a natural process really."
When asked if the dam releases had anything to do with the current flooding Mr Barnes replied "no".
The dam is at 100 per cent when the water supply is full, but it can hold an extra 1.5 million megalitres of water - taking it to 200 per cent - for flood mitigation.
Between Friday when the state government began releasing water to "reassure people" to 6am Monday when it shut the floodgates again, the water level fell from 91 per cent to 88 per cent.
By Monday afternoon it had risen to 119 per cent.
More water will be released from Wivenhoe once floodwaters start to recede, by which time the dam level is predicted to be 140 per cent.
Seqwater's spokesman Mike Foster said the government's decision to reduce the dam to 88 per cent had given engineers extra flood storage space.
"The best way to explain it is the drinking water compartment is 100 per cent full and we've started to store water in the flood compartment," he said.
"For us the message is the majority of the flood mitigation storage, is well and truly available for use."