Riverkeeper Ian Penrose said the river was doing well after recent rains, but still had less than half the run-off it needed and was not being managed sustainably.

‘‘We can’t manage the rainfall or know how long this rain will last,’’ Mr Penrose said. ‘‘But we can control the use of the river’s water and that’s not being done responsibly or sustainably.’’

With roughly 70 per cent of Melbourne’s water drawn from the Yarra catchments, last year just 28 per cent of run-off was allowed to flow downstream.

Mr Penrose has started lobbying in electorates along the river for a guaranteed 60 per cent of run-off for the river and investment in stormwater harvesting and water recycling to make up the difference.

He said three-quarters of Melbourne’s water ended up in the sewer system and an amount equalling Melbourne’s annual water use flowed from drains into the bay each year. ‘‘The pollies will say the public isn’t ready to drink toilet water, but that’s not responsible leadership – if it’s the right thing to do they need to get behind it,’’ he said.

State government spokesman Chris Owner would not comment on the proposals but said the government had released 17 billion litres of environmental flows for the Yarra River this year.

But Mr Penrose said a further 10 billion litres had been taken from the river since that promise was made and that environmental flows were a bare minimum for the river’s survival, not a sustainable target.