No change to seasonal determinations in northern Victoria

The Resource Manager for northern Victoria today updated the 2021/22 seasonal determinations.

The Murray, Goulburn, Campaspe and Loddon systems remain at 100 per cent of high-reliability water shares (HRWS).

Seasonal determinations in the Broken and Bullarook systems stay at 100 per cent HRWS and 100 per cent of low-reliability water shares (LRWS).

Resource Manager Mark Bailey said continued strong flows into the major storages were adding to 2022/23 reserves.

“Our immediate priority is to secure enough water to support the seasonal determinations to high-reliability water shares in 2022/23,” Dr Bailey said.

“This action considers what is in storage now plus the statistical flows into the storages that occur 99 years in every 100 for the remainder of 2021/22 and into 2022/23.

“Effective today, the Murray system needs another 410 gigalitres of water before reserves are sufficient for 2022/23 allocations to high-reliability water shares and any seasonal determination to low-reliability water shares this year can occur. The volume needed in the Goulburn system is 530 gigalitres. 

“These volumes can be reached through a combination of further inflows and tributary flows into the major river systems lowering this year’s commitments.

“Further deductions from Murray spillable water accounts are also contributing, About 37 gigalitres, or 35 per cent of the current spillable account volume, will be deducted with today’s announcement and go towards the reserve.

“Further deductions should be expected at the next December 2021 seasonal determination update after the Murray-Darling Basin Authority commenced releases on 10 November to manage Lake Hume close to its full supply level.”

The latest Bureau of Meteorology seasonal outlook favours above-average rainfall across the northern Victoria for the December to February period. The Bureau’s La Niña alert remains in place, meaning the chance of a La Niña event forming is around 70 per cent. The negative Indian Ocean Dipole event has weakened to neutral levels. A negative Indian Ocean Dipole and a La Niña event each increase the likelihood of above-average rainfall totals in south-east Australia.

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 in the Victoria’s share of both Hume and Dartmouth reservoirs below 50 per cent. While the risk of spill at Lake Hume is effectively 100 per cent, the risk of spill at Dartmouth is less than 5 per cent and this is where trade adjustments will occur.

The current risk of spill in the Murray system allows 200 GL of net trade from New South Wales to Victoria as this would increase the risk at Dartmouth to about 10 per cent. This volume will be updated with each risk of spill announcement. Customers can find out more about trade opportunities and a trial of improved trade adjustment methods on the Victorian Water Register website.

An interim rule for trade from the Goulburn, Broken, Campaspe and Loddon systems to the Victorian Murray system, New South Wales and South Australia is in effect from 1 July 2021 to 30 June 2022, replacing the previous rule that had been in place since 2013. The new trade rule means that until December 15, 2021, trade is allowed whenever the total amount owed from the Goulburn to the Murray, including the Lower Broken Creek, is less than 190 GL. From December 15, 2021, net trade will be capped and the inter-valley trade account balance will be run down.

The volume currently committed to the Murray is 190 GL, meaning trade from the Goulburn, Broken, Campaspe and Loddon systems to the Victorian Murray system, New South Wales and South Australia is closed. More details about the new trade rule are available at the  Victorian Water Register website.

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  Victorian Water Register website.

The Murray-Darling Basin Authority (MDBA) is restricting trade of water allocations from above the Barmah Choke to downstream of the Choke 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 next risk of spill update will be released on Friday 10 December 2021.
• The next 2021/22 seasonal determination announcement will be released on Wednesday 15 December 2021.