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Australia

Murray-Darling Basin dams and catchments nearly full, as flows into South Australia reach six-year high

Water flowing into South Australia has hit a six-year high at 53 gigalitres a day, as a report reveals full storages and wet conditions across the Murray-Darling Basin.

The Murray-Darling Basin Authority’s (MDBA) Murray River annual outlook, released yesterday, showed southern basin storages are at unusually high levels for this time of year, with the Hume Dam sitting at 95 per cent capacity.

It comes as the Dartmouth Dam records 97 per cent capacity, the Menindee Lakes sits at 115 per cent capacity and Lake Victoria at 62 per cent.

The MDBA said the storages have been bolstered by healthy flows entering the Murray River from the Murrumbidgee and Goulburn rivers and other Victorian tributaries.

“The primary purpose of both the Dartmouth and Hume Dams is to store water to meet irrigation and other entitlements, so that’s our focus,” MDBA executive director of river management, Andrew Reynolds said.

He said irrigators and environmental water entitlement holders were in a good position to receive full entitlements this season, and that the MDBA was set up to manage the risk of shortfalls.

“If we do get a sudden hot period of weather and a spike in demands, it can be a bit harder for us to manage, but we’ll work closely with the Bureau of Meteorology to adapt to the season ahead,” he said.

A road flooded with water
Some roads and walking paths around the Riverland have been flooded.(Supplied: Gabriella Fraser)

Caution urged for river users

At the South Australian border, Murray River flows have reached 53 gigalitres of water a day for the first time in six years, prompting one river council with low-lying areas to issue a formal warning.

Mid Murray Mayor Dave Burgess said river users and property owners in the district are encouraged to be wary of faster currents, higher water levels and submerged debris.

“We don’t expect to reach flood risk levels, but based on current forecasts, we’re encouraging property owners and residents to take precautions just in case,” he said.

When flows reach above 60GL a day at the SA-Victoria border, low-lying areas and flood plains become inundated and flood advice is issued to shack areas between Cadell and Mannum.

An image of the murrumbidgee river at gundagai
Recent rains in the Murrumbidgee catchment will flow down to South Australia in September.(ABC Riverina: Olivia Calver)

Even bigger flows on the way

Heavy rains in the upper parts of the Murray and Murrumbidgee catchment last weekend totaled up to 150 millimetres in rainfall in some areas, which means South Australia’s flow levels are yet to peak.

The MDBA has commenced airspace management releases from the Dartmouth and Hume Dams, and big releases from Burrinjuck Dam in the Murrumbidgee system.

Department for Environment and Water manager of water delivery Chrissie Bloss said peak flows were still four to six weeks away.

“It’s really too early to forecast what those peaks might look like, but what we know for certain is that flows will be elevated for some months in the Riverland,” she said.

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Categories
Australia

Murray system reaches full allocation before spring making river operators and landholders ‘nervous’

Authorities are warning landholders downstream of the Hume Dam near Albury-Wodonga to prepare for flooding as spring approaches.

Up to 100 millimetres of rain is predicted this week in Victoria’s north-east and the New South Wales Southern Riverina region with Upper Murray, Mitta Mitta, Kiewa, Ovens, and King rivers expected to see flooding.

After a fairly dry July, Hume Dam is sitting at 92 per cent capacity and is expected to fill this season.

The dam filled in September last year.

Yesterday the Murray-Darling Basin Authority (MDBA) advised landholders downstream from Hume Dam “to be flood ready as we enter the wettest period for southern basin catchments.”

MDBA executive director of river management Andrew Reynolds said the Hume Dam currently had 250 gigalitres of airspace available before the dam was considered full.

“We’ve been in close contact with the Bureau of Meteorology, we’re anticipating that we will be able to manage this rain event with the airspace that we have got,” Mr Reynolds said.

“We will make further releases to preserve further airspace in advance of future events.”

Farmers downstream of Hume Dam said the abundance of water already in the system was “very concerning.”

Chairman of the Murray River Action Group, Richard Sarsgood, said landholders along the Murray would be checking storage levels every day in anticipation of flooding.

“Everybody is watching this coming rain event and we’ll see how much airspace it soaks up in Hume Dam,” he said.

“By the next rain event people will start looking at moving stock to higher ground or out on agistment.”

Murray at full allocation

Irrigation season officially starts on August 15. Already Victoria irrigators have their 100 per cent high reliability allocation.

A dam wall has water being released.
Hume Dam reached capacity in September 2021 for the first time since 2016.(Rural ABC: Annie Brown )

Resource manager with Goulburn Murray Water, Mark Bailey, said this was the earliest the system had reached full allocation in 20 years.

“The last time we were at this level was 2002/2003. It’s something that we haven’t seen in a very long time,” Mr Bailey said.

Authorities are anticipating a wetter year, warning irrigators and landholders to expect more water.

“It’s something that makes a river operator quite nervous in terms of what’s happening with potential inflows and where the dams are,” Mr Bailey said.

‘High probability’ Dartmouth will spill

Further upstream from Lake Hume, Victoria’s largest capacity dam in Dartmouth is sitting at around 95 per cent capacity, holding 3.8 million megalitres of water.

The view of Dartmouth Dam's signage over the water.
Dartmouth Dam is Victoria’s largest storage with a capacity of 4 million megalitres.(Rural ABC: Annie Brown)

The last time Dartmouth dam spilled was in October 1996, and excitement has been building that the mega dam could overflow for the first time in more than a quarter of a century.

“There’s a reasonably high probability that Dartmouth will fill this year,” MDBA’s Andrew Reynolds said.

“It is a much bigger storage than Hume, however it’s also has a much smaller catchment upstream, so the inflows are not necessarily as large.

“We’re not pre-releasing water from Dartmouth because it would just make its way into Hume and we would have more water to manage there.

“At the moment it’s better that we protect the airspace at Hume Dam.”

Living on the floodplain

A full river.
The Murray system has reached full water allocation.(Rural ABC: Annie Brown)

Richard Sarsgood has been farming along the Murray River outside Howlong, NSW, for 66 years.

Among the 120 members of the River Action Group living between Lake Hume to Yarrawonga, Mr Sarsgood said there was a higher concern for flooding this year with an abundance of water already in the system in August.

“There’s a lot of concerned landholders and tourism operators because the system has been fully charged since February,” Mr Sarsgood said.

“With the rain event this week, and future events, there’s a lot of concern there’s going to be repeat flooding like in previous years.

“To the MDBA’s credit, they have drawn Hume dam down to 92 per cent which is a step in a right direction.

“However with Dartmouth so full, and the Bureau of Meteorology predicting a wetter than average next three months, we are really concerned the flooding will be heading our way.”

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