THE FLOODY TRUTH
Suburb bounces back as experts release findings
A FORENSIC review has found no evidence of illegal levees or dams contributing to floods that tore through Redlynch Valley in March.
An independent study handed down today identifies the massive build-up of debris in waterways as a key factor in the surging floodwaters that left holiday-makers fearing for their lives and destroyed courts at the Redlynch Valley Tennis Club.
As the tennis club and BIG4 Crystal Cascades Holiday Park rebuild, residents affected by the one-in-100year floods have been awaiting the results of the review for months.
Cairns Regional Council says it regularly cleans up creeks that form the region’s drainage network.
MASSIVE debris and sediment build-up has been identified as a key contributor to floods that tore through Redlynch Valley in March.
A forensic review into the deluge will be presented to Cairns Regional Council’s infrastructure committee this morning.
BMT principal hydraulic engineer Neil Collins found no evidence of illegal levees collapsing in Currunda Creek or causing flooding downstream.
Rather it was huge amounts of drenched vegetation and churned-up “scour” or sediment that blocked creek crossings and exacerbated flooding.
Swiftwater rescuers were forced to swoop on the BIG4 Cairns Crystal Cascades Holiday Park in the early-morning darkness on March 27 to ferry dozens of holiday-makers from harm.
“Major flood debris blockage on the Currunda Creek crossing of Redlynch Intake Road exacerbated flooding locally in Currunda Creek and downstream, with significant flood flow breakout to the north and south occurring,” the review says.
“It is important to appreciate that large debris loads in largely undeveloped forested catchments in the Wet Tropics is a natural phenomenon.”
A guard rail collapse on the Redlynch Intake Rd creek crossing could also have resulted in “localised rapid surge in downstream flood levels”.
Mayor Bob Manning said rooting out the causes of the flooding was a priority.
“I don’t think we ever used the term ‘illegal damming’ but there was some concern about bank collapse, and where you get trees collapsing into the creek and being washed down,” he said. “Bear in mind that we’re talking about a onein-100-year event – it was this massive impact which was gone very quickly.”
The council is responsible for an annual program to assess and clear waterways within the drainage network.
“Additional clearing of litter and debris is undertaken as required,” a council spokeswoman said.
IT IS IMPORTANT TO APPRECIATE THAT LARGE DEBRIS LOADS IN LARGELY UNDEVELOPED FORESTED CATCHMENTS IN THE WET TROPICS IS A NATURAL PHENOMENON FLOODING REVIEW