NSW dam levels soar as Sydney water restrictions remain in place
Sydney's dam levels have jumped almost two-thirds in less than a week, with the recent heavy rains delivering more than a year's worth of water demand or as much as eight years of output from the city's desalination plant.
The leap in reservoir levels poses a dilemma for the Berejiklian government given it had only introduced level-2 water restrictions for Sydney, the Blue Mountains and Illawarra in December.
Lake Burragorang, behind Warragamba dam, is now almost 70 per cent full after nearing 40 per cent just days ago.Credit:Wolter Peeters
Those curbs, which include a ban on watering gardens between 10am and 4pm each day, remain in force, Premier Gladys Berejiklian said on Monday.
The rapid increase came after Sydney and much of eastern NSW recorded the most rain from a single event in decades. Sydney alone collected almost 400 millimetres over four days, or more than Melbourne had in 2019.
The city's storages have soared to 71.4 per cent full as of Tuesday morning, up from 43 per cent on Friday, WaterNSW said. Volume in the dams surged about 736 billion litres over the five days, or far more than the 566 billion litres of drinking water supplied by SydneyWater during the 2018-19 fiscal year.
For Warragamba, which makes up about 80 per cent of Sydney's storage, the level has risen to 69.3 per cent full.
The increase of about 553 billion litres since Friday alone would have all but met the city's annual water needs, and more big net-inflows are likely in coming days as water makes its way through the catchment.
While less than the big flows over the weekend, inflows over the past 24 hours amounted to a gain of 8 percentage points - or more than 13 per cent - in dam levels from the previous day.
By contrast, dam levels had been dropping about 0.4-0.5 percentage points a week over the past two years as the drought choked inflows.
That reduction excluded the impact of the desalination plant, which had been operating at full capacity for more than six months. At full tilt, the plant produces 250 million litres a day - a tally surpassed almost 3000 times by the dams' inflows so far.
The desalination plant operator also has the option of running the facility - which can supply about 15 per cent of Greater Sydney's water demands - for a minimum period of 14 months, according to the 2017 Metropolitan Water Plan.
That 14-month allowed operating period following the restart trigger will be up late next month, a spokeswoman for the plant said.
"If a decision is made to stop production, the flow immediately ceases and the plant is gradually shutdown within the confines of the process," the spokeswoman said.
The Herald has approached Water Minister Melinda Pavey and SydneyWater for comment.