Engineer logged dam strategy after floods

AAP

A flood engineer recorded the type of water release strategy used in the lead-up to the Brisbane and Ipswich floods after the event, Queensland’s flood inquiry has been told.

Nine days of extra hearings are being held in Brisbane to examine allegations Wivenhoe dam engineers failed to move fast enough to a higher water release strategy, W3, which is designed to protect urban areas from inundation.

Reports in The Australian have suggested the dam banked too much water as a result, and authorities were later forced to make massive releases quickly, possibly compounding the flooding.

The first day of the extra hearings has been told the dam reached 68.5 metres at 8am on January 8, 2011, the weekend before the floods hit Brisbane.

That level is the trigger point for the water release strategy to move from W1, which gives primary consideration to minimise disruption to downstream rural life, to W2 or W3, which are designed to protect urban areas from inundation.

Flood engineer for SEQWater, John Tibaldi, on Thursday told the inquiry there had been up to 50 drafts before the final report on Wivenhoe’s operations was published by SEQWater in March last year.

The final report stated there had been a jump from the W1 strategy, to W3, at 8am on January 8, bypassing W2.

However drafts of the report told a different story, that engineers moved to the W3 strategy much later.

One report said engineers transitioned from W2 to W3 between 7pm on January 9 and 1am on January 10, the inquiry was told.

In another report, that transition was recorded as happening between 2pm and 7pm on Sunday, January 9.

Mr Tibaldi said he ultimately decided that engineers moved from W1 to W3 at 8am on January 8, without moving through W2.

“The release rates were just too high,” he told the inquiry.

He said he held concerns about the leap because it didn’t comply with the flow chart in the dam’s manual, which he had helped to script.

Although he was concerned about the non-compliance, he said it would not have been sensible to adopt W2 at that time.

The jump to W3 ultimately helped reduce the flood peak in Brisbane, he said.

He defended the continual changes over what strategy was in place at what time.

As more data came in after the flooding event he tried to match that to a water release strategy and ultimately he stands behind SEQWater’s final report.

“I wanted to paint the full picture of the flood event, good and bad,” he told the inquiry.

“It’s a warts-and-all account, for better or worse.

“Our thoughts were … it’s out there and people can judge us.

“We weren’t about saying we did good or bad.”

Counsel assisting the inquiry, Peter Callaghan, said Mr Tibaldi and the other four Wivenhoe Dam engineers had all given evidence that W3 was in place at 8am at January 8.

Four independent experts had also found there had been compliance, the inquiry heard.

However, Mr Callaghan told the inquiry that there are no contemporaneous records to support their evidence.

“No contemporaneous records existed as to when flood engineers moved to W3,” he told the inquiry.

“It was observed that the log did not make any note of decisions to change strategy, nor of the reasons for such decisions,” he said.

In absence of records the Commission took the word of SEQWater and the engineers in its interim report, which was handed down last August.

The additional inquiry hearings will examine when W3 was enacted and whether the engineers and SEQWater misled the Commission.

Mr Callaghan said The Australian had alleged the dam was not operated in the way presented to the inquiry.

“The suggestion is a serious one,” he said.

“It involves questions not only as to how the dam was managed but as to how the public and the commission have been informed about the January event.”

The hearing continues.

Earlier, Premier Anna Bligh said she had been asked to submit a written statement to the inquiry.

She said that would be done by Monday, and she would also submit a copy of her diary and relevant documents relating to the meetings and briefings she attended at the time of the floods.

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