BRISBANE and Ipswich residents at risk during floods because new manual for controlling dam has same failings as before, expert says.

The criticism comes as hundreds of families in the southeast struggle to rebuild their lives, a year after their homes and businesses were devastated, The Courier Mail said.

Many flood victims were surprised by the damage suffered in locations thought to be safe from flooding or protected by the dam.

All are keeping a weather eye out after being told last year by the Bureau of Meteorology to expect more heavy rain this summer.

The Commission of Inquiry into the floods in August ordered dam manager Seqwater to come up with an interim revision of the manual in time for the wet season after Judge Cate Holmes called the document "a bit of a mess".

The State Government approved the new manual in October.

But veteran engineer Max Winders, who warned in May of problems with the old manual, said the new version was no better and Seqwater's changes were "there to protect what they did in 2011".

He said the manual was still too simplistic and failed to take into account the complexity of the floodplain.

It also still relied on the judgment of operators but without giving them the tools to do their job properly.

"There's nothing new in there," he told The Courier-Mail. "You need a manual that tells you how to minimise the problem, not, 'use your discretion'."

Minister for Natural Resources Rachel Nolan said she was confident that the review leading to the current manual had been "appropriate and thorough".

Mostly it had involved technical and language issues, she said.

"That's what the commission asked for and that's what the experts did," she said.

Mr Winders, who gave expert testimony to the inquiry on his work for Brisbane Council on downstream impacts of the January 2011 flooding, is a consultant with 50 years' experience advising companies and public authorities on flood mitigation.

He said the manual's failure to focus on river heights down-river in a rapidly changing environment meant operators had no way of knowing how much damage they might do.

"(The revised manual) doesn't do anything because it doesn't set the target for minimising the damage, it just delays the peak (of the flood)," he said.

"That's very nice for Fernvale and Lowood but by the time it gets to Brisbane you need a dynamic model."

Seqwater said it had such a model "available" but the body had "no role in forecasting water levels or issuing flood warnings".

The new manual stresses the need to keep river flows at Moggill at less than 4000 cubic metres of water per second (cumecs), the threshold for serious damage in urban areas.

But Mr Winders said: "Much more damage was done (in 2011) by letting 7500 cumecs go at the wrong time and this manual does nothing to prevent that".

The revised manual has expanded the flow charts that engineers use to decide what dam release strategy to follow.

But Mr Winders said such situations were "too complex for yes/no boxes".

The document also tells engineers to "usually" give "zero or little weight" to 24-hour Bureau of Meteorology forecasts in determining flood mitigation strategies. The bureau declined to comment.

The inquiry also called for a longer-term review of the manual. Ms Nolan said this "optimisation study" would be completed by the end of this year and a new draft then prepared.

The inquiry's final report will be published on February 24.

Read more at The Courier-Mail.