Campaspe is predicted to have 100 per cent HRWS, while the Broken and Bullarook systems are likely to start on zero HRWS.
However, the Broken, Goulburn, Loddon and Bullarook systems are forecast to reach 100 per cent HRWS by mid-October, and the Victorian Murray system by December —under average inflow conditions.
In contrast, at the same time last year, forecasts for the 2023-24 season were 70 per cent for Goulburn and Loddon, and 60 per cent for Murray.
Irrigators opened the season on August 15, 2024, with 76 per cent HRWS in Murray, 92 per cent for Goulburn and Loddon, and 100 per cent for Campaspe.
Northern Victorian resource manager Andrew Shields said conditions had been very dry.
“Catchment areas across northern Victoria have received little rainfall in recent months,” Mr Shields said.
“As a result, flows into the major storages have been well below average.
“Flows into the Menindee Lakes provided some additional resource in the Murray system.
“Considering these factors and an estimate of the volume carried over, seasonal determinations in the Murray, Goulburn and Loddon systems should begin 2025-26 with about 25 per cent high-reliability water shares (HRWS) or better.”
Mr Shields said the Campaspe system was expected to receive 100 per cent HRWS due to the reserves established during 2024-25.
“As annual systems, the seasonal determinations in the Broken and Bullarook systems rely on catchment conditions and the volume of carried over allocation,” he said.
“Due to low reserves, we anticipate seasonal determinations in both the Broken and Bullarook systems will start 2025-26 at zero per cent HRWS.”
The estimates for the new season in all Goulburn-Murray Water systems were released on Thursday, May 15, the same day as the 2024-25 irrigation season officially ended.
The first 2025-26 seasonal determination announcement will be released on Tuesday, July 1, with the season starting on August 15.
Mr Shields said inflow conditions during 2025-26 would determine how seasonal determinations change during the year.
“Average inflow conditions should allow the Broken, Goulburn, Loddon and Bullarook systems to reach seasonal determinations of 100 per cent HRWS by mid-October 2025.
“Murray system seasonal determinations may not reach 100 per cent until December under average inflow conditions.
“Dry conditions and water released to meet demands through autumn has reduced storage levels in the Murray, Goulburn and Campaspe systems.
“The risk of spill is expected to be about 45 per cent at the start of July 2025 in the Murray and Campaspe systems. The risk of spill in the Goulburn system is expected to be about 30 per cent in early 2025-26.
“Customers in these systems should factor the risk of spill into their plans for the remaining months of 2024-25.”
An assessment of the probability of spill in the Murray, Goulburn and Campaspe systems will be released on July 1.
Tables that summarise the estimated high-reliability water share seasonal determinations through the season for each scenario in the Murray, Goulburn, Loddon, Campaspe, Broken and Bullarook systems are available at the NVRM Current Outlook webpage.
Seasonal determinations under additional scenarios for each system are available from the NVRM Additional Scenarios webpage.
