LAKE Hume and the Dartmouth Dam could both be full within the next few days, greatly increasing the likelihood of flooding.
Low-lying areas downstream of each reservoir will be at significant risk if there is a major rain event in the next few weeks.
Landowners in those areas are being told to be vigilant and watch rainfall upstream of the dams.
Hume will reach 99 per cent within the next few days, while Dartmouth will follow soon after.
Downstream residents at risk of having their properties flooded have been briefed by the Murray-Darling Basin Authority over the past couple of weeks.
Its river management executive director, David Dreverman, said yesterday Lake Hume was deemed to be effectively full at 99 per cent.
“We keep ourselves just 1 per cent air space to mitigate any potential inflow event,” he said.
“Because we’re going to have Dartmouth also full, we’re going to maximise our water availability for water users.”
Mr Dreverman said that meant both Dartmouth and Hume had to be at 99 per cent capacity on the day that demand exceeded inflows.
That has required constant adjustment to releases from Hume and Dartmouth since early this month.
At one point, up to 29,000 megalitres a day was going through the Hume dam, though this tapered off to about 14,000 megalitres early this week and yesterday the flow was about 10,000 megalitres, though heavy rain from storms that swept through on Thursday night could lift this again.
Similar adjustments have been made on an almost daily basis for Dartmouth.
Mr Dreverman spoke to The Border Mail late yesterday after teleconferencing with managers at Dartmouth and Hume.
He said the authority appreciated many people were feeling nervous.
“But we are operating absolutely strictly and very carefully in accordance with the objectives and outcomes that have been set for us by departments of government as part of the Murray-Darling Basin Initiative,” he said.
“We’re watching very carefully, but it’s a time for people who live on the floodplain downstream of either Dartmouth or Hume to be keeping a very close watch on rain events in the upper catchments.
“Most of them are very well informed and most of them are aware of the risks of living on a floodplain.”
Mr Dreverman said the past four big flood events upstream of Hume had been mitigated by the storage in the past year.