Low-reliability water share seasonal determination for the Murray system

Low-reliability water share seasonal determination for the Murray system

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

The Murray system increases from 100 per cent of high-reliability water shares (HRWS) to 100 per cent HRWS and 12 per cent of low-reliability water shares (LRWS).

The Goulburn, Campaspe and Loddon systems remain at 100 per cent HRWS.

Seasonal determinations in the Broken and Bullarook systems stay at 100 per cent HRWS and 100 per cent LRWS.

Resource Manager Mark Bailey welcomed the first LRWS seasonal determination in the Murray system since 2016/17.

“Stored resources, plus the statistical inflows used in our two-year allocation cycle, can fully support seasonal determinations against Murray high-reliability water shares in 2022/23,” said Dr Bailey.

“We have enough water for a 12 per cent seasonal determination for low-reliability water shares this year.

“Continuing flows into the Menindee Lakes and Lake Hume have provided the resource,” Dr Bailey added. “Further releases to control the level in Lake Hume have also contributed, with another 93 gigalitres deducted from spillable water accounts with today’s announcement.

“All Murray spillable water accounts are now empty, although increases to the seasonal determination for low-reliability water shares this season could see more water added.”

Dr Bailey said the other northern Victorian systems had not received resource improvements on the same scale as the Murray.

“The Goulburn system still needs another 510 gigalitres of water before reserves are sufficient for 2022/23 allocations to high-reliability water shares.”

The Bureau of Meteorology seasonal outlook for the January to March period does not strongly favour above or below-average rainfall across northern Victoria. La Niña conditions have established in the tropical Pacific and are expected to remain until the end of summer. The negative Indian Ocean Dipole event has weakened to neutral levels. La Niña conditions increase the likelihood of above-average rainfall totals in south-east Australia.

The seasonal determinations for northern Victorian water systems on Wednesday, December 15 are:

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 40 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 interim trade rule means that from December 15, 2021, net trade will be capped and the inter-valley trade account balance will be run down.

As Goulburn high-reliability water share seasonal determinations are 100 per cent, the full volume of legacy entitlement commitments must be supplied from the Goulburn to the Murray system this year. This means that on 15 December no additional trade opportunity will be released from quarantined legacy commitments. 

In accordance with the interim trade rule cap, after 15 December, additional trade opportunity will only be created when allocation is traded back from the Victorian Murray system, New South Wales or South Australia into the Goulburn, Broken, Campaspe or Loddon systems. 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 Monday January 10, 2022.
• The next 2021/22 seasonal determination announcement will be released on Monday January 17, 2022.