100 per cent high-reliability water share seasonal determinations for all northern Victoria systems

The Resource Manager for northern Victoria today updated the seasonal determinations for 2022/23 water availability.

The Goulburn and Loddon systems increase from 93 per cent of high-reliability water shares (HRWS) to 100 per cent HWRS. The Campaspe system moves from 82 per cent HRWS to 100 per cent HRWS. The Broken system increases from 57 per cent HRWS to 100 per cent HRWS and 48 per cent of low-reliability water shares (LRWS).

The Murray system seasonal determination remains at 100 per cent HWRS. The Bullarook system seasonal determination stays at 100 per cent HRWS and 100 per cent LRWS.

Resource Manager Mark Bailey said it was 25 years since seasonal determinations in all systems had reached 100 per cent this early in the water year.

“All northern Victorian systems now have at least 100 per cent HRWS available after strong streamflow responses to rainfall during August,” Dr Bailey said.

“The last time that all systems had 100 per cent HRWS (or its equivalent) available at the start of September was in 1997/98.

“The response in the Goulburn catchment above Lake Eildon prompted Goulburn-Murray Water to release water in late August to slow the rate of rise in the storage,” Dr Bailey said. “About 7 gigalitres will be deducted from Goulburn spillable water accounts with today’s announcement. That’s about 2 per cent of the current volumes in the spillable water accounts.”

“The deduction from Murray spillable water accounts due to continuing releases to manage Lake Hume levels during August will be confirmed in the September 15 seasonal determination update,” Dr Bailey said. 

“As releases to manage Lake Hume and Lake Eildon volumes will carry on, Murray and Goulburn system entitlement holders should expect further deductions from spillable water accounts.

“With the seasonal determinations at 100 per cent and a wet season predicted, we anticipate keen interest in the potential for LRWS allocations this year,” Dr Bailey added. About 1,040 gigalitres is needed in the Murray system and 500 GL in needed in the Goulburn system before LRWS is allocated in these systems.

“These volumes will reduce when system operating requirements and demands are met without releasing water from storage and as deductions occur from spillable water accounts.”

Dr Bailey said further rainfall was likely, with longer term predictions favouring wetter conditions. “The latest Bureau of Meteorology forecast suggests above-average rainfall will continue through to December.”

Dr Bailey noted that as seasonal determinations were now 100 per cent HRWS, updates will now occur monthly on the 15 ^th of each month or next business day.

Trading opportunities

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 from Victoria’s share of both Lake Hume and Dartmouth Reservoir below 50 per cent. Presently, allocation trade from New South Wales to Victoria is not possible because Victoria’s shares of Lake Hume and Dartmouth Reservoir are full. The opportunity for allocation trade is updated with each risk of spill announcement. Customers can learn more about trade opportunities and a trial of improved trade adjustment methods on the Victorian Water Register website waterregister.vic.gov.au/about/news/267-trial-of-improved-trade-adjustment-methods.

A new trade rule for trade from the Goulburn, Broken, Campaspe and Loddon systems to the Victorian Murray system, New South Wales and South Australia came into effect on July, 1 2022. Further trade opportunities will be announced in October and December based on seasonal conditions. From December, net trade will be capped.

The Goulburn, Campaspe and Loddon systems can trade from the Victorian Murray system, New South Wales and South Australia while the total volume owed to the Murray system is greater than zero.

Customers participating in the water trading market can monitor trade availability on the Water Register website, waterregister.vic.gov.au/water-trading/allocation-trading.

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 www.mdba.gov.au/managing-water/water-markets-trade/interstate-water-trade/barmah-choke-trade-balance.

Upcoming Resource Manager Announcements

• The risk of spill in the Murray, Goulburn and Campaspe systems will be updated on Monday September 12, 2022.
• The next 2022/23 seasonal determination announcement will be released on Thursday September 15, 2022.