Sydney, Darwin, Brisbane and Melbourne are all facing the prospect of dams below 50% capacity after low rainfall and high temperatures across the country.
In Sydney, inflows are at their lowest since 1940. Greater Sydney’s 11 dams were at a combined 55% capacity on Sunday – compared to 73% at the same time last year.
Sydney activated its desalination plant in January, when dam levels dropped below 60%, but levels continue to drop 0.4% a week. Stricter water restrictions will come into effect if the level drops below 50%. The last time Sydney’s dam levels neared 50% was in 2011.
In the Northern Territory, the Darwin river dam received its lowest-ever rainfall in March, as the territory recorded its driest wet season in 27 years. On Sunday, Darwin’s dam was at 76% capacity, compared with 98% last year.
In Melbourne, dam levels were at 51% on Monday, compared with 59% last year and 61% the year before.
Last month, Melbourne Water warned that storage “hasn’t been this low since April 2011”.
In Queensland, the south-east was also reaching a 10-year low. Neil Brennan, the chief executive of Seqwater, said in April that water levels were at their lowest since February 2010. Brisbane’s dams were at 70% capacity on Sunday, down from 82% last year.
Dry conditions and lower-than-average rainfall are expected to persist through the autumn and into winter, with the Bureau of Meteorology’s climate outlook predicting a “drier than average” May for eastern Australia.
It follows a record-breaking summer and the hottest March on record.
On Monday, Peter Hatfield from Sydney Water told radio station 2GB that “we just haven’t had enough rainfall in the past couple of years.”
He said people need to “become mindful of water, and treat it like the valuable resource that it is”.
In Sydney, a series of permanent Waterwise rules are already in place, which ask residents to only water gardens before 10am and after 4pm, and ban the hosing of driveways unless for health or safety reasons.
However, further restrictions will come in once water levels fall below 50%. A Sydney Water spokesman said the precise make up of the restrictions is “still being finalised”.
Similarly, in Melbourne, a series of permanent rules have been in place since 2012.
There are currently no water restrictions in place in Darwin, and it is the only capital city in Australia that has never had them.
Hatfield also said that Sydney had begun receiving water from its desalination plant in the middle of March. “They are currently ramping up production,” he said. “The full production is 15% of Sydney’s drinking supply. Once the desalination plant is up to max capacity, in the coming months, there will be a 15% reduction in the draw from Sydney’s dams.”