The New South Wales government was advised six months ago that Sydney’s water storage levels could be at “emergency levels” by May next year unless it started planning immediately.
A cabinet-in-confidence document prepared by state-owned agency WaterNSW warns that storage levels could fall to 40% by Christmas and were likely to reach what are considered emergency levels – about 35% and declining – by mid-next year if the coming summer is hot and dry.
The WaterNSW document says inflows since early 2018 had been the lowest on record and water use across the city had been higher than expected. It had increased the risk that some critical supply areas, such as the Illawarra, may run out of water in about two years.
Titled “drought supply options study”, the document says storages will become increasingly difficult to manage if they fall below 30%. Storages have depleted at a faster rate during this drought than during the millennium drought, when they fell to 33%.
It does not explicitly mention climate change, but warns of the need to plan for “a scenario where climate doesn’t follow history and we get a follow-up drought before recovery”.
“The only options left to us at this point are large-scale desalination plants,” it says.
The NSW Greens’ water spokeswoman, Cate Faehrmann, said the document showed the government’s 2017 metropolitan water plan was based on data from the 1939 drought, and ignored years of expert warnings of lower water availability due to climate change and population growth.
“It’s grossly negligent for the government to be planning for water security based on historical trends. Unless they factor in reduced water availability under a hotter climate we don’t stand a chance,” she said.
A spokeswoman for the water minister, Melinda Pavey, said the government was investigating measures to support Sydney’s water supply and was already taking steps.
People in Sydney use more water per person than Melburnians, but the spokeswoman said water use in Sydney fell last financial year, both in total and per capita terms, after investment in water efficiency programs.
The government had also preemptively introduced level one water restrictions when dam levels reached 53.5%, before the 50% trigger was reached, and last week announced that level two restrictions would start on December 10, ahead of the 40% trigger point. Average per person water use had fallen from 211 litres to 183 litres a day, the spokeswoman said.
She said the government was considering expanding the city’s desalination plant, which is operating at full capacity and supplies 15% of daily water demand, and work had commenced on a strategy to be released next year that would integrate water and sewerage planning.
It could increase the use of recycled sewage water, a step long called for by experts. “This will be an adaptive plan for Sydney’s water and sewerage needs out to the year 2080,” the spokeswoman said.
Faehrmann said experts had urged the government to invest in large-scale water recycling and stormwater harvesting during the millennium drought but consecutive administrations had failed to act.
She said Pavey needed to explain why she did not introduce more water saving measures after receiving the WaterNSW advice in May. “She knew all of this while Sydney had no enforced water restrictions whatsoever,” she said.
Wright, a senior lecturer in environmental science, said the government should adopt a water pricing mechanism similar to other states that charged consumers higher rates when they used large amounts. “It is the only jurisdiction that doesn’t have blocked pricing,” he said.
He said bringing in level two restrictions earlier than planned and considering an expansion of desalination was welcome, but said the desal plant should have been operating at full capacity much earlier. He urged the government to do more. “Where are the big recycling projects?” he said.