Low-reliability water share seasonal determinations for the Goulburn and Loddon systems

The Resource Manager for northern Victoria today updated the 2023/24 seasonal determinations.

Seasonal determinations in the Goulburn and Loddon systems increase from 100 per cent of high-reliability water shares (HRWS) to 100 per cent HRWS and 19 per cent of low-reliability water shares (LRWS).

The Broken system seasonal determination increases from 100 per cent HRWS and 20 per cent LRWS to 100 per cent HRWS and 100 per cent LRWS.

The Campaspe system moves from 100 per cent HRWS and 65 per cent LRWS to 100 per cent HRWS and 74 per cent LRWS.

Seasonal determinations in the Murray and Bullarook systems remain unchanged.

Resource Manager Mark Bailey said recent large inflows into the Goulburn system and early season water use contributed to today’s announcement.

“Dry conditions through August and September increased demand for water, creating space in the dams,” Dr Bailey said.

“Rainfall in early October has refilled many of the major storages.

“The additional resource, together with the use, meant there was water available to increase seasonal determinations.”

Releases to manage storage levels at Lake Hume and Lake Eildon since the mid-September seasonal determinations mean that there will be deductions from spillable water accounts.

“About 110 gigalitres will be deducted from Murray spillable water accounts today, which is equivalent to about 43 per cent of the volume currently held in the accounts,” Dr Bailey said.

“In the Goulburn system, about 130 gigalitres will be deducted from spillable water accounts, or close to 43 per cent of the volume in these accounts.

“There are no deductions from Campaspe spillable water accounts with today’s update.

“The shortfall to announcing seasonal determinations for low-reliability water shares in the Murray system is about 110 gigalitres.”

The seasonal determinations for northern Victorian water systems on Monday 16 October are:

Trading Opportunities

Allocation trade opportunity from the Goulburn, Broken, Campaspe and Loddon systems to the Victorian Murray system, New South Wales and South Australia is limited to the volume of opening trade opportunity available at the start of the water year, plus any additional trade opportunities available in October and December based on seasonal conditions and spills from legacy commitment reserves. Spills that occurred earlier this water year, as well as additional spills announced today against these legacy commitments of approximately 15 GL, mean that some of the commitments to supply water from the Goulburn system no longer needed to be delivered. Any reduction in these commitments can be released as additional trade opportunity on top of seasonal trade opportunity calculated based on irrigation water use in the Murray system.

The total volume of trade opportunity available from the Goulburn, Broken, Campaspe and Loddon systems to the Victorian Murray system, New South Wales and South Australia based on current water use in the Murray and spills against legacy commitments, will be about 88 GL. The release of this trade opportunity has been postponed from the planned October 16 opening. For more information about how the trade rule works and when trade opportunity will be available please see the  Victorian Water Register website

Allocation trade from New South Wales to Victoria is limited to the lesser of a net annual volume of 200 GL or a volume that keeps the risk of spill in the Victoria’s share of both Hume and Dartmouth reservoirs below 50 per cent. As Victoria’s share of Hume and Dartmouth is close to full, trade from New South Wales to Victoria is not possible. The volume available for trade is updated with each risk of spill announcement. 

Customers participating in the water trading market can monitor trade availability on the Water Register website

The Murray-Darling Basin Authority (MDBA) has announced that trading of water allocations from above the Barmah Choke to downstream of the Choke is restricted to protect the delivery of downstream water entitlements. Customers can monitor trading opportunities across the Barmah Choke on the MDBA website

Upcoming Resource Manager Announcements

• The risk of spill in the Murray, Goulburn and Campaspe systems will be updated on Friday 10 November 2023.
• The next 2023/24 seasonal determination announcement will be released on Wednesday 15 November 2023.