Authorities said that “dangerous and high velocity flows” had been reported along the Ross River.
They warned that the danger was due to “unprecedented flooding,” forcing officials to order the full opening of the floodgates of the dam on Sunday night, releasing about 1,900 cubic meters of water a second.
Even after the release, as of Monday morning, the dam was still at 229 percent capacity, holding about 532,000 gigaliters of water, dam officials reported.
A record 1.16 meters of rain has poured across the Townsville area over the past seven days.
The huge downpour of rain prompted authorities to issue major flood warnings for several rivers in the area.
‘Crocs on streets’
There have been several saltwater crocodile sightings on the streets and roads in the Townsville area.
Local officials say there have been more than a thousand emergency calls for help. Emergency services have struggled to respond to the scale of the disaster, carrying out 18 “swift water rescues” overnight.
Australia’s military has been deployed to help tackle what is described as “once-in-a-century” floods.
“We’ve never seen so much water in our lives," said local radio journalist Gabi Elgood. "You think there can't possibly be any more to come but the rain just doesn't stop."