Lake George is covered in water and the dam giving shape to Lake Burley Griffin has opened floodgates as rain drenches the ACT and surrounding regions.
While far from full, Lake George is covered by water after steady rainfall in the region on Saturday and Sunday, transforming the landmark after years of drought.
Farmers on motorbikes rounded up sheep onto dry land in the lake basin as water levels rose on Sunday afternoon.
In Canberra, two of five floodgates opened at Scrivener Dam, releasing torrents of water as operators managed Lake Burley Griffin's levels during the rainfall.
Rising levels at the Molonglo River, Queanbeyan River, and other Lake Burley Griffin tributaries prompted the release of water on Sunday.
Nearly 40mm of rain fell in northern parts of the ACT while the territory's south had 30mm of rainfall in the 24 hours to 9am as a coastal trough deepened across the NSW coast.
By comparison, Canberra Airport recorded 17.8mm of rain in August 2019, and 5mm a month earlier.
The ACT's State Emergency Service has responded to 78 calls for assistance since Friday, however the steady flow of lighter rainfall has prevented large scale damage to property across the territory.
Weather bureau meteorologist Alex Majchrowski said rain had fallen steadily across the region this weekend.
"It is a lot of rainfall for Canberra," he said.
The nation's heaviest falls were in southern parts of Australia, particularly coastal areas, which had recorded 200mm in rainfall.
The coastal trough would head north to the NSW mid-north coast, Mr Majchrowski said.
"It's going to take the weather with it. From tomorrow, we're not expecting much for the ACT," he said.
A six-month turnaround
Water has returned to Lake George after years sitting dry as the climate grew hotter and drier.
Australian National University geologist and emeritus professor, Patrick De Deckker, said the lake was filled with water in the early 1980s but became nearly dry by the middle of that decade.
"It's had a bit of water since, but I never saw the lake fill up again because of the climatic conditions at the moment," he said.
Water filling the lake in recent years disappeared into the sediment, pushed laterally by strong wind.
Despite the water covering Lake George this weekend, it would take longer, more sustained periods of high rainfall to fill the lake completely, Professor De Deckker said.
"We have a water table underneath Lake George, so you have to have a lot of water for the water to be close to the surface," he said.
"If it keeps on raining, then the lake basin fills and will retain for some time."
Large rainfall in summer is also needed to maintain water levels in the lake, he said.
Lake George, which has hosted regattas and swimming races when full, has previously sat empty of water during dry conditions in World War Two and during the Federation Drought.
In October, it will be 200 years since NSW governor Lachlan Macquarie renamed the lake after the British king.
The weekend's rainfall has prompted the National Capital Authority to open Scrivener Dam's floodgates only six months after dry conditions lowered Lake Burley Griffin's water levels. In February it was 550mm below normal lake level.