Flows of up to 135 gigalitres per day are now expected in early December in the River Murray, 15 gigalitres higher than previously forecast, the South Australian government has warned.
Continued rainfall throughout parts of the Murray-Darling Basin over the past week has prompted today's revision, up from last week's forecast of 120 gigalitres per day.
"It is possible that figure will go up with further rain events in Victoria," Deputy Premier Susan Close said.
"It’s also quite likely that if there’s further rain further north in the northern parts of the basin and the northern parts of Victoria, rather than there being a much higher figure it will be that amount of water coming for a longer period."
Dr Close urged locals and property owners in the Riverland to start planning for this "high water and low flooding event".
The state government has announced $3 million to prepare local communities for the increasing flows.
The government will distribute the funds directly to affected Riverland councils to stabilise the levee systems surrounding a number of towns and communities.
"We're aware there are some concerns about the levee system throughout the Riverland, in particular two levee banks that have been drawn to our attention very early on in Renmark," Dr Close said.
"The government has therefore determined to allocate $3 million initially to work with councils — primarily the Renmark council but not exclusively — to work through being able to remedy the gaps in those levee banks so that as we get over the 130 gigalitres that was being identified previously as a challenge for the riverbanks, that we are prepared to withstand the water lapping over the edges.
"The hospital bank for example, at 130 gigalitres, is when the water will start to require the levee bank to be intact.
"If it has gaps, that is the point at which the water will start to flow through.
"So we're now at a position where we know that's very likely to be the experience in early December, so therefore we need to make sure the remediation works have been undertaken."
Dr Close said the Department for Environment and Water (DEW) and the SES were in the Riverland assessing the levee banks and determining what remediation works were required and working with councils for action to be taken.
"This is a live issue at present, but we want to reassure the community that, united with the councils, we are working on this, we are preparing for what will be coming," she said.
SES focusing on Renmark
SA State Emergency Service Chief Officer Chris Beattie said work in Renmark would be the first priority.
"Most of the towns within the Riverland sit above the flood plain, the townships themselves," he said.
"Renmark is the most exposed, it's got the most extensive levee network around it and so therefore that's where we are putting our attention first.
"But there are other parts across the Riverland too where there are levee systems that we'll also be looking at."
Mr Beattie said further upward revisions to the forecast were possible.
"The modelling takes into account the water that's in the system now, it doesn't take into account any predictions of future rain events," he said.
"... It's not beyond the realms of possibility that we continue to see an increase in these forecasts if we see more rain in the eastern seaboard."
Mr Beattie said another weather system "of interest" would cross the state over the weekend, with severe and heavy rain expected statewide on Sunday.
Tourists urged to keep coming
Bill Nehmy, the tourism development manager for the Murray River, Lakes and Coorong Tourism Alliance, said visitors could check to see if their plans would be affected.
The SES has a dedicated page for information about the high flows.
Mr Nehmy said most South Australian River Murray towns were not low-lying like those in Victoria and would not be flooded.
"It's a long river and there are different pockets and different nuances as you go along," he said.
"We're just saying to people, 'be vigilant but don't stop your planning, don't stop your trip'."
Maps produced by DEW show of all the major towns along the Murray in South Australia, Mannum would be the most affected, with others only facing flooding in the lowest-lying areas.
Dave Hartley, who rents out holiday homes between Murray Bridge and Morgan through his business River Shack Rentals, said they were all above the level of the record-breaking 1956 flood.
He urged people to continue to support tourism operators but not to come to the region to "sticky-beak".
"Come along, have a look at the region; there's so much more to do in the region than just being on the river," he said.
"There's certainly a lot of other opportunities so come and have a look."
