The Resource Manager for northern Victoria today updated the 2021/22 seasonal determinations.
The Murray system moves from 57 per cent of high-reliability water shares (HRWS) to 77 per cent HRWS. The Goulburn and Loddon systems increase from 71 per cent HRWS to 85 per cent HRWS.
The Campaspe system moves from 97 per cent HRWS to 100 per cent HRWS. The Broken system rises from 81 per cent HRWS to 100 per cent HRWS and 41 per cent of low-reliability water shares (LRWS).
Seasonal determinations in the Bullarook system stay at 100 per cent HRWS and 100 per cent LRWS.
Resource Manager Mark Bailey said recent rainfall provided a welcome increase in water availability.
“The catchments responded well to the rain in early September,” Dr Bailey said.
“The volume of water in storage increased and higher tributary flows downstream of the storages met demand, which allowed for today’s increased allocations.
“The Murray-Darling Basin Authority is also managing Lake Hume close to the full supply level. This action is reducing the volume of rules-based accounts in the Murray system, and may cause deductions from spillable water accounts if releases continue for some time.
“Any deductions from spillable water accounts will be determined in early October and included in the October 15 seasonal determination assessment.”
The latest Bureau of Meteorology seasonal outlook continues to favour above-average rainfall across the northern Victoria for the three month period from October to December. The negative Indian Ocean Dipole has weakened but continues and the Bureau has also issued a La Niña watch meaning the chance of a La Niña forming is around 50 per cent. A negative Indian Ocean Dipole and La Niña each increase the likelihood of above-average rainfall totals in south-east Australia.
The seasonal determinations for northern Victorian water systems on Wednesday 15 September are:
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 10 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 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 2021/22 seasonal determination announcement will be released on Friday 1 October 2021.
- The next risk of spill update will be released on Monday 11 October 2021.