Residents along the Murray River in South Australia have been told daily data on water flow into the state is inaccurate as flooding continues.
On Thursday, the state government revealed official daily flow data at the South Australian border, used to measure the amount of water heading along the river into the state, differed from the true figure.
At the beginning of the day, data showed flows into the state were 157 gigalitres for the day.
But at a press conference later in the day, it was confirmed flows were actually around 180GL.
Despite this discrepancy, there is no change in the predicted peak of river flows later this month, with authorities forecasting flows of between 190GL and 220GL at the border around Christmas Day.
Authorities had initially warned of a peak in Renmark about December 14 and another peak later in the month, but now only the one peak is expected close to Christmas.
Department for Environment and Water (DEW) executive director of water and the River Murray Ben Bruce said authorities realised around a week ago there was a difference between what was expected to be coming across the border each day and what was being officially recorded.
"You're looking at something that is normally 150 metres wide, and it is currently 6 kilometres wide," he said.
"The MDBA (Murray Darling Basin Authority) … have a team in the field at the moment doing some estimates, which make much more sense and fit in with our predictions much more.
"We're quite relieved the number makes much more sense given what we were forecasting and what we were seeing upstream, and what we were seeing around Renmark and other townships."
Riverland resident Steven Kernich said the change took him by surprise.
"I [work] on a property out at Pike River and Lyrup Heights [and] we noticed the water levels were coming up a lot higher than the flows that were being reported," he said.
"Now we've got some pump stations and a new one, which has been built for 56 flood levels, and we've only got six foot left until the pump station will be inundated.
"We've got to find out how much higher this water is going to go."
All according to plan
South Australian Premier Peter Malinauskas said the flow forecasts and modelling had broadly been consistent with flood event expectations.
"As it currently stands, flows are at that 180-odd-GL level … which is largely in line with forecasts," he said.
"But we also know the peak will accentuate around Christmas and that will sit between the range of 190GL with the outside possibility of getting to 220GL.
"We've always been planning for 250GL, so that remains unchanged."
However, Mr Malinauskas was sympathetic to river communities confused by the reporting failure.
"The frustrating element has been these particular readings at the border and the confusion that has arisen from that," he said.
"We haven't seen an event like this in South Australia for over 50 years ... that is bringing with it technical difficulties that only the experts can fully account for."
The DEW and the MDBA are currently in the process of refining their modelling to allow for more accurate flow reporting.
