- Mixed rainfall across the southern and northern Basin
- Long-range forecast for autumn predicts below average rainfall is likely
- The likelihood of water quality issues reduces with the onset of cooler conditions
- Conditions across the Basin remain favourable for blue green algae outbreaks.
Drought
After a dry February, below average to very much below average rainfall continued through March throughout most of Victoria, south-eastern South Australia and parts of eastern New South Wales. Rainfall was in the lowest 10% of Marchs since 1900.
A large area of the northern Basin received average to above rainfall, with a small section of the upper Condamine-Balonne catchment receiving very much above average rainfall.
Despite this higher rainfall in the northern Basin, small areas of the eastern states, particularly in north-eastern New South Wales, continue to present longer term rainfall deficiencies (11 to 16 months).
In March, root zone soil moisture was average to above average over much of Australia. However, low rainfall in South Australia and Victoria resulted in very much below average soil moisture.
Rainfall
It was a wet month up north with highest rainfall for the northern Basin recorded in the upper Condamine–Balonne catchment in the Roma region, with more than 150mm.
Highest rainfall for the southern Basin was recorded in the Murrumbidgee catchment, with more than 60mm in the Riverina region
Scattered areas of the lower southern Basin were significantly drier than the rest of the Basin, with some locations recording no rainfall for the month of March.
Water storages and streamflow
As of 27 March 2024, total storage in the Basin was 17,104 GL (77%), which is a 4% decrease from February. Northern Basin storages decreased by 1%, southern Basin storages by 5%, and the Lachlan catchment by 4%.
The Murray River is now regulated from Hume Dam to the South Australian Border. This autumn, a dry outlook and regulated conditions will see a return to lower flows across the River Murray system, as water is conserved in Hume Dam to support future allocations.
Releases at Dartmouth Reservoir continue above the minimum to help balance the risk of spill between Dartmouth and Hume Dams while responding to demand downstream of Hume.
Downstream on the Kolety, inflows from the Edward Escape are helping meet higher demands in the Kolety-Wakool system.
On the Darling (Baaka), flows from Weir 32 were reduced with water for the environment on top of base flows to support water quality outcomes upstream of Weir 32.
Outflows continue at Lake Victoria (Tar-Ru) to meet entitlement requirements at the South Australian border and lake storage volume in accordance with the Lake Victoria Operating Strategy (LVOS) as specified in the Objectives and Outcomes for River Operations in the River Murray System.
Climate outlook
The Bureau’s long-range forecast indicates that for April to June, below median rainfall is likely (60% to 80% chance) across South Australia, Victoria, western and southern inland New South Wales, and south-western Queensland.
Maximum and minimum temperatures are likely to very likely to be above median for most of Australia.
The long-range forecast is influenced by several factors, including record-warm oceans globally and a weakening El Niño.
Water quality
The likelihood of water quality issues reduces with the onset of cooler conditions. Basin rivers and storages are nutrient rich and conditions remain favourable for blue green algae outbreaks.
Summary of key water quality issues
- Low dissolved oxygen: In the lower Darling (Baaka), dissolved oxygen levels generally remain above critical ecological thresholds as conditions have become cooler. Low dissolved oxygen levels are no longer being recorded immediately downstream of Hume Dam. This is due to Lake Hume de-stratifying with the onset of cooler weather. This means that as the water cools, the entire water column becomes mixed and low oxygen levels are no longer an issue with the water that is released.
- Blue-green algae: There is currently a risk of blue-green algae across most parts of the Murray–Darling Basin, particularly in New South Wales and Victoria. An advisory notice for blue-green algae is also currently in place for Lake Alexandrina in SA. For the latest information on blue-green algae alerts, contact the relevant state government contacts via the Getting information about current algal blooms page of our website.
- Elevated Salinity: Some of the Menindee Lakes and parts of the lower Darling River (Baaka) are seeing elevated salinity levels. This is not expected to have any significant impacts across the border into South Australia.
Water quality in the Murray–Darling Basin is monitored by individual Basin state governments. Specific water quality alerts are issued by respective states.
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