A spokesman for the state's water authority says the dam doesn't have a flood mitigation component, so no water was released ahead of the downpour, which came when the state's dam network was already 97% full. He said the dam wasn't to blame for the flooding.

"It's quite an extraordinary weather event. Warragamba does spill into a particular river system for sure, but there are a whole vast areas of Sydney that are flooded that aren't downstream of Warragamba," the spokesman said.

It's a startling turnaround from just 15 years ago when the state decided to build a desalination plant to safeguard Sydney's water supply after years of drought.

But this year the La Nina weather system generated more rainfall, and the Bureau of Meteorology says there's a 50-50 chance of it forming later in 2022 -- twice the normal likelihood. The climate crisis is expected to increase the frequency and intensity of both La Nina and El Nino, which causes drought -- that means, if La Nina does form again this year, there could be yet more rain.

A spokesman for the state's water authority says the dam doesn't have a flood mitigation component, so no water was released ahead of the downpour, which came when the state's dam network was already 97% full. He said the dam wasn't to blame for the flooding.

"It's quite an extraordinary weather event. Warragamba does spill into a particular river system for sure, but there are a whole vast areas of Sydney that are flooded that aren't downstream of Warragamba," the spokesman said.

It's a startling turnaround from just 15 years ago when the state decided to build a desalination plant to safeguard Sydney's water supply after years of drought.

But this year the La Nina weather system generated more rainfall, and the Bureau of Meteorology says there's a 50-50 chance of it forming later in 2022 -- twice the normal likelihood. The climate crisis is expected to increase the frequency and intensity of both La Nina and El Nino, which causes drought -- that means, if La Nina does form again this year, there could be yet more rain.