Casting around for someone to blame for the Brisbane floods continues and there is an excellent article in the Australian considering the issue of whether the Wivenhoe damn should have been emptied earlier (H/T Aynsley Kellow, in the comments). There is a fairly damning quote from a local hydrologist:
When they finally did release [water from the dam], it was because they had received so much inflow this week that they were afraid the whole system would collapse. There is no doubt in my professional opinion that most of the flooding in Brisbane should have been avoided. It is extraordinary to me that people are not asking more questions about this. Brisbane should have been protected by Wivenhoe Dam. Instead, the dam is a large part of the reason the city has flooded.
There is also, however, this word of caution from an engineer who was involved in the dam's construction:
"These questions are all valid, but put it this way - you would have to have very large balls to [significantly reduce the dam's volumes in the months after the weather warnings] after 10 years of drought, because if you had got it wrong you would be accused of wasting the water"