Murray joins other systems with 100 per cent of high-reliability water shares

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

The Murray system moves from 93 per cent of high-reliability water shares (HRWS) to 100 per cent HRWS.

The Broken system increases from 100 per cent HRWS and 85 per cent of low-reliability water shares (LRWS) to the maximum available 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 Bullarook system stay at 100 per cent HRWS and 100 per cent LRWS.

Resource Manager Mark Bailey said the Murray system reached 100 per cent HRWS as strong flows into all major storages continued with recent rainfall.

“The sustained flows into the Murray system have provided enough resource to repay all of the borrowed Barmah-Millewa Forest Environmental Water Allocation and announce the 100 per cent allocation,” Dr Bailey said.

“There are also further deductions from Murray spillable water accounts. About 165 gigalitres, or 61 per cent of the current spillable account volume, will be deducted with today’s announcement.

“Further deductions should be expected while the Murray-Darling Basin Authority maintains pre-releases to keep Lake Hume close to its full supply level.” 

With all northern Victorian systems reaching at least 100 per cent HRWS, Dr Bailey noted interest in the availability of seasonal determination against low-reliability water shares is expected to increase.

“We will confirm the volume of additional resources needed to make a low-reliability water shares seasonal determination in the Murray system at the next seasonal determination update,” Dr Bailey said.

“At present, the Goulburn system needs another 600 GL for a low-reliability water shares allocation. This volume is needed in addition to the inflows we expect in 99 years in every 100 for the remainder of 2021/22 and into 2022/23.”

Dr Bailey also reminded entitlement holders that as seasonal determinations in all systems were 100 per cent HRWS, future 2021/22 seasonal determination updates will be released on a monthly basis.

“In accordance with our policy, the next update of seasonal determinations will be released on Monday, November 15,” Dr Bailey said.

The latest Bureau of Meteorology seasonal outlook favours above-average rainfall across the northern Victoria for the November to January period. The Bureau has issued a La Niña alert, meaning the chance of a La Niña event forming is around 70 per cent. A weak negative Indian Ocean Dipole event continues and is expected to return to neutral levels in late spring. 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 about 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 30 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 Wednesday 10 November 2021.
• The next 2021/22 seasonal determination announcement will be released on Monday 15 November 2021.