Sharleen 'hit the panic button' when flow data lost meaning amid South Australia's River Murray flood
Anxiety was rising as Sharleen Lloyd's property became an island during the flood. (Supplied: Sharleen Lloyd)
Sharleen Lloyd will never forget the day she lost all faith in the flow data she had always trusted to keep her family and home safe.
Daily flow reports have long been vital to river communities like hers to understand how much water is coming across the South Australian border.
Sent out by the state government, the flow data was crucial for the Lloyd family to plan during the River Murray floods in 2022/23.
But as water levels crept up toward their slice of paradise near Lyrup on December 9, 2022, the Department for Environment and Water (DEW) revealed the data was no longer useful.
"We had to hit the panic button," Ms Lloyd said.
Trees stained by the flood remind Ms Lloyd how much water surrounded her home. (ABC Riverland: Sophie Landau)
Usually a hidden escape in nature, the Lloyd's home is nestled in the Murray River National Park.
But as the river rose, so too did Ms Lloyd's anxiety.
There was no guarantee the levee could hold back one of the biggest floods in the state's history, so the family had to just sit and wait.
"It was pretty stressful not knowing," she said.
The day they questioned everything
On December 9, flows at the SA border were 157 gigalitres (GL) per day, but flood height markers at Renmark indicated river levels were similar to the 1974 flood, around 180GL per day.
It was the day Premier Peter Malinauskas revealed the discrepancy to the public, and explained it would be investigated further.
Ms Lloyd felt like she could no longer rely on any data.
"One road flooded then the other road was slowly coming up," she said.
"We had to get everything out very quickly, so we could get out with the boat."
Sharleen and Garry Lloyd could only access their home by boat during the flood. (Supplied: Sharleen Lloyd)
Island of isolation
The family property became an island only accessible by boat.
It was an isolating time for Ms Lloyd's husband Garry, who held down the fort while she continued working.
"He was more or less housebound for months, just in case something did happen," Ms Lloyd said.
Jasmyn Lloyd (left) was in the middle of uni exams in Adelaide but she rushed home to help her family. (ABC News: Simon Goodes)
Their 23-year-old daughter Jasmyn, was in Adelaide studying to become a doctor — but after the announcement on December 9, she felt things were too unpredictable.
"That was the point where I came home to help out. We didn't really know if the levee was going to be alright," she said.
"I was in the middle of my uni exams, so I sent an email just explaining, 'There's a situation at home, I can't really do anything about it'.
"Every week we were getting told different things ... it made everything a whole lot more stressful, that's for sure."
The Murray River National Park surrounding the property was inundated with once-in-a-generation flows. (Supplied: Sharleen Lloyd)
Flow-on effects
A joint investigation between DEW and the Murray-Darling Basin Authority (MDBA) explored why flows of 157GL per day at the border could equate to river levels seen during the 1974 flood at 180GL per day.
One possibility was that measuring tools could not accurately account for all the flow, due to the massive increase in the river's width from about 150 metres to about 6 kilometres.
But this was not the case.
A flood marker at the property showing flood levels came up to around 17.75 metres Australian Height Datum (AHD). (ABC Riverland: Sophie Landau)
"MDBA hydrographers were sent to gather in-river measurements ... and found that flow at the SA border was being calculated accurately," DEW acting director of water infrastructure and operations Lisa Stribley said.
"This meant that the discrepancy observed was primarily due to changes in the catchment since 1974 and, in some cases, 1956."
Factors impacting the river levels include significant changes to the topography, like roads and levees, as well as increased vegetation and changes to the riverbed during the 48 years between the floods.
It did not change DEW's forecast flood range of 190GL per day to 220GL per day, however flow reports increasingly referred to river levels using the Australian Height Datum (AHD) instead.
Like many river families, the Lloyds use sticks to mark water levels all year round. (ABC Riverland: Sophie Landau)
Learn from the locals
Back on Sharleen Lloyd's property, she looks at the levee and is reminded it was spared by floodwaters one year ago.
Along the river's edge, sticks mark the spots where high flows reached last spring.
It is the family's own form of flood modelling — a passion and skill taken up by many river communities watching the water ebb and flow throughout the year.
The state government's mid-year budget review includes $2.5 million for DEW to create a new flood model, and survey changes to the channel and flood plain since previous floods.
But Jasmyn Lloyd said if there was any lesson to be learnt from the recent flood, it was to listen to the locals.
"Surveying can only go so far," she said.
"Listen to the community. They were on the ground at the time, they would know a lot more."