Cyclone Alfred: Dam operators still won’t release water until rain starts

South East Queensland’s dam operator has doubled down on a decision not to release any water before Cyclone Alfred hits, but has revealed its rationale.

South East Queensland’s dam operator has doubled down on a decision not to release a single litre of water before Tropical Cyclone Alfred hits, arguing this could make flooding worse.

Dam operator Seqwater – laying out its plans publicly after repeated requests from Premier David Crisafulli – also confirmed it would be sticking to the rules of the flood manual drawn up after the 2011 flood disaster.

CEO Emma Thomas said dam operators still did not know exactly where the rain would fall, from what direction it would arrive, and how quickly it would move – warning the release of water now could inadvertently make flooding downstream worse.

The southeast’s dam manual dictates decisions about when and whether to release water should be based on rain that had actually fallen.

The Bureau of Meteorology’s latest forecast had Cyclone Alfred crossing the coast about 1am on Friday at Redcliffe, about 90km from Lake Wivenhoe.

Wivenhoe Dam is 86 per cent full, Somerset Dam is at 80 per cent and North Pine Dam just 1.2 per cent below capacity, but Seqwater underlined the flood compartments of all three were empty.

“We don’t know exactly where that rainfall will come, and we don’t know from what direction, and we don’t know if the cyclone, as it passes, will move through quickly or slowly,” Ms Thomas said.

Water is released from Wivenhoe Dam in 2022.

“So again, we have to really pay attention, and that’s why our senior flood engineers are so critical to this task, because as that storm moves around and as different rainfall patterns happen in different catchments, we’ll be able to understand just where it’s flowing.

“I think we are all concerned about what Tropical Cyclone Alfred will bring, not just the people along the Brisbane River, but also people along coastal areas where the message has been very clear that we haven’t seen (an event of this scale) in Brisbane for 50 years.”

Seqwater fronted the public for the first time this week after Water Minister Ann Leahy instructed the government body to provide Queenslanders with transparency.

Mr Crisafulli on Tuesday said it was important Seqwater communicated with Queenslanders, as he defended sticking to the flood rule book.

“They’ve got a system in place, but they have to explain that to Queenslanders – because if they do that, that’s the best way that people can genuinely see why decisions being made,” he said. “You don’t make decisions on the run, Seqwater have to communicate that.”

Principal dam safety, strategy and flood operations manager Kevin Bartlett said dam safety was Seqwater’s primary objective and that there was a huge difference between Wivenhoe’s full storage capacity of 65.9m, and levels that could test structural integrity.