Murray system low-reliability water share seasonal determination reaches 100 per cent

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) and 72 per cent of low-reliability water shares (LRWS) to 100 per cent HRWS and 100 per cent LRWS.

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

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

Resource Manager Mark Bailey said very wet conditions in the Murray system improved the volume available for allocation.

“January rainfall was very much above average, which generated strong flows into both Dartmouth Reservoir and Lake Hume,” Dr Bailey said.

“The additional resource helped the Murray seasonal determinations reach maximum availability for the first time since the introduction of the current entitlement products in 2007.”

Further releases by the Murray-Darling Basin Authority to control the water level in Lake Hume occurred in January.

“A total of 120 gigalitres will be deducted from Murray spillable water accounts with today’s announcement,” Dr Bailey said.

Dr Bailey said the other northern Victorian systems received smaller resource improvements.

“Despite some storm activity and rainfall during January, the other Victorian systems reported limited flows into storage,” Dr Bailey said.

“The Goulburn system needs another 460 gigalitres of water before reserves are sufficient for 2022/23 allocations to high-reliability water shares, which is little improved on last month.”

The Bureau of Meteorology seasonal outlook for the March to May period does not strongly favour above- or below-average rainfall across northern Victoria. La Niña conditions continue in the tropical Pacific and are expected to remain until mid-autumn. La Niña conditions 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. Trade adjustments will occur in Dartmouth where there is storage capacity available before occurring in Hume.

The volume in Hume Reservoir is expected to reduce in the coming months as demand for water increases and inflows decrease. As a result, the 200 GL net annual allocation trade limit will apply. There is currently about 90 GL of net trade from New South Wales to Victoria available under this limit. 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 since December 15 2021, net trade is capped and the inter-valley trade account balance is being run down.

In accordance with the interim trade rule cap, since 15 December, additional trade opportunity is only 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 Thursday March 10, 2022.
• The next 2021/22 seasonal determination announcement will be released on Tuesday March 15, 2022.