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| NEW IDEA NEEDED: Ipswich was hit by rising flood waters but a levee is not viable. |
BUILDING a levee to protect the Ipswich CBD from a repeat of the 2011 floods has been ruled out as unviable.
In January 2011, water from the flooding Bremer River flowed out at Devil's Gully beside the river and under the rail overpass on Marsden Pde before steadily inundating the central business district including the Coles supermarket.
In the wake of the floods, Ipswich City Council pledged to investigate whether a barrier could be built to stop water going through Marsden Pde.
Council chief executive Carl Wulff told the Flood Commission of Inquiry in October 2011 it was "probably the glaring example of a possibility, depending on cost and other issues".
In March 2011, Ipswich bricklaying contractor John Glynn told The Queensland Times he suggested filling in under the bridge with a reinforced wall beside the rail line.
But this week, the council ruled out a levee bank, wall or floodgates, finding the main impasses were the stormwater drains and the ability of the railway embankment to hold back floodwater.
"As promised after the January 2011 flood, Ipswich City Council commissioned a high-level feasibility study which was undertaken by industry experts. Floodgates or a similar approach for Marsden Pde were investigated," Mayor Paul Pisasale said.
"While floodgates may appear to the layperson to be an easy solution, it is critical to understand that a gate alone will not stop floodwaters backing up in the complex underground network of stormwater drains, outlets and grates.
"Even more importantly, the railway embankment was not designed or built to act as a dam wall. It is not clear if the bank could withstand the immense pressure of floodwaters and to act as a flood embankment.
"It is likely the whole embankment would need to be either rebuilt or significantly reinforced to the point that to do so renders the project unviable.
He said more case-by-case solutions could be examined to alleviate the flood affect.
Chamber of Commerce president Brett Kitching said it seemed other answers would have to be sought to avoid future flooding.
"From a business point of view, it would be great to have those businesses not to have that threat, if a levee was built. There was an awful lot of heartache and financial loss," Mr Kitching said.
"It would be fabulous if it could be built, but if the engineering advice is that it can't be done - if it's not practical, possible or feasible - then that's what we have to go with."
In January 2011, water from the flooding Bremer River flowed out at Devil's Gully beside the river and under the rail overpass on Marsden Pde before steadily inundating the central business district including the Coles supermarket.
In the wake of the floods, Ipswich City Council pledged to investigate whether a barrier could be built to stop water going through Marsden Pde.
Council chief executive Carl Wulff told the Flood Commission of Inquiry in October 2011 it was "probably the glaring example of a possibility, depending on cost and other issues".
In March 2011, Ipswich bricklaying contractor John Glynn told The Queensland Times he suggested filling in under the bridge with a reinforced wall beside the rail line.
But this week, the council ruled out a levee bank, wall or floodgates, finding the main impasses were the stormwater drains and the ability of the railway embankment to hold back floodwater.
"As promised after the January 2011 flood, Ipswich City Council commissioned a high-level feasibility study which was undertaken by industry experts. Floodgates or a similar approach for Marsden Pde were investigated," Mayor Paul Pisasale said.
"While floodgates may appear to the layperson to be an easy solution, it is critical to understand that a gate alone will not stop floodwaters backing up in the complex underground network of stormwater drains, outlets and grates.
"Even more importantly, the railway embankment was not designed or built to act as a dam wall. It is not clear if the bank could withstand the immense pressure of floodwaters and to act as a flood embankment.
"It is likely the whole embankment would need to be either rebuilt or significantly reinforced to the point that to do so renders the project unviable.
He said more case-by-case solutions could be examined to alleviate the flood affect.
Chamber of Commerce president Brett Kitching said it seemed other answers would have to be sought to avoid future flooding.
"From a business point of view, it would be great to have those businesses not to have that threat, if a levee was built. There was an awful lot of heartache and financial loss," Mr Kitching said.
"It would be fabulous if it could be built, but if the engineering advice is that it can't be done - if it's not practical, possible or feasible - then that's what we have to go with."
www.QT.com.au
15.1.13
