Clarence is braced and ready for floods
AUTHORITIES are ready to tackle predicted flash floods across the Clarence Valley.
Civil engineering experts say it is time to act after new research analysing three decades of weather patterns revealed rising temperatures could bring massive downpours and destructive flooding to the region.
The dire prediction suggests storm-driven peak rainfall patterns will intensify as the Valley heats up.
University of New South Wales researcher Professor Ashish Sharma said every Australian town and city was at risk.
"It means that most people in Australia can expect to see intensification in the magnitude of flash flooding in smaller catchments, particularly in urban or residential areas," he said.
Professor Sharma and his School of Civil and Environmental Engineering colleagues based their findings on 30 years of data collected at 79 weather stations across the country.
"We have linked increased temperatures to less uniform rain patterns within storms," lead researcher Conrad Wasko said.
"This suggests that more rainfall will be dumped over a shorter time."
Clarence Valley Council works and civil director Troy Anderson said the organisation's flood model accounted for rising ocean levels and a 10% increase in rainfall.
"Council's flood model has used very conservative assumptions in terms of ocean level, which is the main determinant of flood levels downstream of Maclean," Mr Anderson said.
"The conservative ocean level means that the council's adopted flood levels downstream of Maclean already accounts for predicted sea level rise for the year 2100.
"The council flood model has also considered the impact of a 10% increase in rainfall and suggests that this increase would cause increases in flood levels of up to 0.4m in most areas."
The research was first published in the Nature Geoscience journal.
BY THE NUMBERS
$200m - Value of Clarence Valley Council's flood mitigation assets.
110km - length of levees in the region.
50 - bridges in the region.
500 - floodgates in the region.
250 - flood mitigation drains in the region.
$4m - Cost of Ulmarra riverbank rock armouring
$5m - Amount NSW Government has spent since 2012 on a range of studies, plans and infrastructure works in the Clarence Valley, Kyogle, Richmond Valley, Lismore and Ballina local government areas.
Counting the cost of keeping the region safe
PROTECTING our region from flooding does not come cheap.
Clarence Valley Council's flood mitigation assets are worth more than $200 million.
These include 110km of levees, 50 bridges, 500 floodgates and 250 flood mitigation drains.
One of the council's major flood mitigation projects was the Ulmarra riverbank rock armouring that cost $4 million.
Other flood works included the levee rehabilitation near the Crown Hotel in Grafton and a bridge and floodgates at Farlows Drain.
The NSW Government has spent more than $5 million since 2012 on a range of studies, plans and infrastructure works aimed at lowering the damage done by rising water levels in the Clarence Valley, Kyogle, Richmond Valley, Lismore and Ballina local government areas.
The Office of Environment and Heritage provides financial assistance and specialist technical advice on flooding to the region's councils.
"Through the OEH Floodplain Management Grant Program in the last three years, 26 projects totalling over $4.4 million have been awarded to these councils to undertake flood studies and plans and to implement and maintain flood infrastructure," an OEH spokeswoman said.
"There are an additional six grants made over the same period totalling $700,000 awarded through the jointly funded Ministry for Police and Emergency Services and Commonwealth Government Natural Disaster Resilience Funding for flood works."