The impact of Launceston’s June 2016 floods could have been quadrupled had the old levee system been in place and failed, according to a Bushfire and Natural Hazards CRC Research report.
The report into the cost-benefit of the new flood levee system said the investment was “a sound economic decision based on the estimated costs at the time of decision making, alongside improved estimates of benefits from this study.”
About 800 cumecs, cubic metres per second, flowed from the North Esk River and 2375 cumecs of water came from the South Esk.
While a number of unprotected homes and businesses near the Tamar Yacht Basin, Newstead, St Leonards and Nunamara were inundated, and Invermay was threatened, the levees held.
The report said Launceston had been subjected to 35 significant floods since records began, with the 1929 flood considered to be the worst.
- Launceston flood levees hold up through first ‘test’
- City Of Launceston predicts Tasmanian floods will cost council millions of dollars
- Launceston high tide brings out best in Tasmanians
- Tasmania floods: how the June 2016 event unfolded | videos
A ten kilometre flood levee system was constructed in the 1960s but by 2005 it was deemed substandard due to the effects of ground settlement and insufficient maintenance.
The final project cost was assessed to be $58 million and included 2 kilometers of earth levee, 700 metres of concrete levee and 16 floodgates.
The council’s infrastructure services director Shane Eberhardt said the CRC report reinforced the importance and effectiveness of the levee system to the city.
“The June floods would have had a much greater impact in terms of overall damage to homes and infrastructure, as well as some level of inundation across the city, had the levees not been in place and worked so effectively,” he said.
Launceston acting mayor Rob Soward said the report vindicated the council's push to undertake the levee reconstruction project.
“The flood levee reconstruction project was a major undertaking for the city, with support from the state and federal governments,” Ald Soward said.
“Now that the project is complete, the city is not only better protected from inundation, but we've opened up new cycling and walking trails, as well as new recreational areas along our waterfront.
“This simply wasn't previously possible when much of those areas were in private hands.”