 |
| Brisbane River Flood January 2011 at Parker Street Goodna facing south near the corner of Edna Street. |
Just over a month before its report is due, an engineering company has told the Queensland Floods Commission the model of the Brisbane River is faulty. The model is used to predict river levels in differing water scenarios but the company says it's flawed.
Tom Nightingale
Source: PM
Transcript:
MARK COLVIN: The report into Queensland's floods last year is a month and a day away. On Sunday a report was delivered to the Queensland Floods Commission that could have a major bearing on its contents.
Last week a key independent witness backed four dam operators, accused of not releasing enough water from a Brisbane dam ahead of the floods. But a local engineering company has come forward dismissing the modelling used to calculate flood levels.
Tom Nightingale reports.
TOM NIGHTINGALE: Predicting the weather is a famously tough ask. Last January, people in Queensland had much more at stake than most, with heavy rain forecast and disastrous floods resulting. What four Brisbane water engineers could have reasonably predicted is a key to the Queensland Flood Commission.
STEFAN SZYLKARSKI: We have some concerns that the model that's actually used is really not able to accurately predict water levels.
TOM NIGHTINGALE: Stefan Szylkarski is the managing director of the Brisbane branch of multinational company DHI. He's not commenting on what Wivenhoe Dam engineers could have predicted. But, speaking to PM from Singapore, he says a flawed model is being used to calculate hypothetical Brisbane River water levels.
STEFAN SZYLKARSKI: It could be higher and lower in different parts of the river. There could be many different outcomes but I think it's essential actually that a proper model is built of the entire river system.
TOM NIGHTINGALE: River modelling involves a virtual example of the river valley, and calculating water levels in different scenarios. Stefan Szylkarski is worried the inquiry will put too much stock in evidence given last week.
STEFAN SZYLKARSKI: Primarily, I think Mark's evidence - that's when really when I became concerned that maybe some of these levels weren't as accurate as they could have be or should have been - and I guess my concern is whether this goes any further.
TOM NIGHTINGALE: The Mark he's referring to is Mark Babister, an independent hydraulic engineer who appeared at the inquiry on Friday. His evidence used the river model to show water levels would have been lower with earlier water releases.
The Wivenhoe Dam engineers are accused of not releasing enough water in advance of the floods, causing the dam to spill too readily once heavy rains came. But Mark Babister defended the engineers, saying more releases were unreasonable, given weather forecasts.
(Excerpt from Mark Babister report)
MARK BABISTER (voiceover): To enact such strategies would have required foresight beyond that obtained from a measured consideration of weather forecasts.
TOM NIGHTINGALE: Mark Babister also said more water releases would have made existing flooding worse
(Excerpt from Mark Babister report)
MARK BABISTER (voiceover): If we didn't have the rest of the rainfall that occurred, we would actually have made flooding significantly worse, worse than would have occurred probably without the dam at all.
TOM NIGHTINGALE: Regardless of the commission outcome, Stefan Szylkarski says a new Brisbane River model is badly needed and won't come in time for either the report or the state election.
STEFAN SZYLKARSKI: It would actually require an additional survey of the Brisbane valley, so the whole project I think would be beyond six and up to 12 months.
MARK COLVIN: Stefan Szylkarski, speaking from Singapore to Tom Nightingale.
15.2.12
