Despite hundreds of millimetres of rain falling in parts of southeast Queensland in the last week, the southeast’s largest and most important dam has fallen to levels as low as during the millennium drought.
It’s prompted a warning from authorities that water restrictions could be implemented if Wivenhoe Dam, which provides more than half the water in the state’s southeast, continues to miss out on much-needed rain.
As of Wednesday, Wivenhoe Dam, 80 kilometres northwest of Brisbane, was at 38.3 per cent capacity. While the dam hit that level in December, prior to that the water storage was last that low in March 2009.
A Seqwater spokesman said at full supply, the dam could store 1,165,240 megalitres of water.
“Our second largest dam, Somerset Dam, flows into Wivenhoe, so the two storages essentially act as one. When we make controlled water releases from Somerset to Wivenhoe it’s to help balance the water levels between the two storages,” the spokesman said.
Water releases began on Tuesday, after parts of the Somerset Dam catchment received up to 200mm of rainfall. It’s estimated the water releases will increase Wivenhoe’s level by between one and three per cent.
While 13 un-gated dams in the region, including Baroon Pocket, Enoggera, Hinze, and Lake Macdonald dams are spilling as a result of recent heavy falls, the overall SEQ Water Grid largely relies on Wivenhoe’s storage level.
Should the grid reach 50 per cent capacity, water restrictions limiting residents to 140 litres of water per person per day will be introduced.
As of Wednesday, the combined water level is at 60.6 per cent, having risen from 57.7 per cent in just five days.
After heavy rainfall late last month, Seqwater CEO Neil Brennan said despite the downpour, communities needed to continue to be waterwise.
“With the region’s combined water level still under 60 per cent, we remain in our drought response phase and ask residents to remain water conscious, especially as we enter our traditional dry season,” he said.
“This time last year, the SEQ Water Grid was at about 70 per cent capacity, and Wivenhoe was about 53 per cent.”
Parts of the Sunshine and Gold Coast hinterlands and the scenic rim were hammered by heavy falls on Monday and Tuesday.
Upper Springbrook received more than 285mm in two days, while Mt Glorious received about 140mm.
Further north, Maleny and Peachester were both hit with more than 170mm over the two days.
A flood warning has been activated for the Stanley River, one of the inflows to the Somerset Dam.
Numerous roads around the region are closed, with motorists urged to check the Queensland traffic website.