Seasonal determinations for 2020/21 increase
The Resource Manager for northern Victoria today announced an update to the 2020/21 seasonal determinations and outlooks.
The Murray system moves from 40 per cent of high-reliability water shares (HRWS) to 55 per cent HRWS. The Goulburn and Loddon systems increase from 58 per cent HRWS to 77 per cent HRWS.
The Campaspe system moves from 82 per cent HRWS to 100 per cent HRWS. The Broken system increases from 92 per cent HRWS to 100 per cent HRWS and 100 per cent of low-reliability water shares (LRWS).
Seasonal determinations in the Bullarook system remain unchanged at 100 per cent HRWS and 100 per cent of LRWS.
Resource Manager Mark Bailey said rainfall since the last seasonal determination update had produced the largest increase in water availability this season in the Murray and Goulburn systems.
“Rainfall on October 7 and 8 boosted flows into the storages to levels well above our conservative estimates,” Dr Bailey said.
“This increased the volume in storage and the amount estimated to flow into the storages over the next few weeks. Both factors contributed to the seasonal distribution improvements announced today.”
Dr Bailey welcomed the full establishment of the early season reserve in the Murray system, which is designed to ensure there is sufficient water available to operate the system and deliver carried over allocation next season.
“Having established the early reserve, the Murray system will now have future resource improvements directed towards seasonal determinations against high-reliability water shares,” Dr Bailey noted.
Dr Bailey said the latest Bureau of Meteorology seasonal outlook favours above-average rainfall across the catchment areas for the three month period from November to January.
“The Bureau has confirmed that La Niña conditions continue in the tropical Pacific Ocean. La Niña events may support above-average rainfall across southeast Australia through spring and early summer.”
The seasonal determinations for northern Victorian water systems on Thursday, October 15 are:
| Murray |
55% |
0% |
| Broken |
100% |
100% |
| Goulburn |
77% |
0% |
| Campaspe |
100% |
0% |
| Loddon |
77% |
0% |
| Bullarook |
100% |
100% |
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 the both Hume and Dartmouth reservoirs below 50 per cent. The current risk of spill in the Murray system allows 200 GL of net trade from New South Wales to Victoria. Customers can find out more about trade adjustments on the Water Register website.
The Goulburn system’s inter-valley trade (IVT) account owes about 283 GL to the Murray system. The Goulburn, Campaspe and Loddon systems can trade to the Victorian Murray system, New South Wales and South Australia while the total volume owed to the Murray system is less than 200 GL.
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.
Allocation trade out of the Broken system is possible when the balance is less than 1,500 ML. As Lake Nillahcootie has filled and is now spilling, the undelivered opening balance of 677 ML in the Broken IVT account will be written off and reduce the account balance to about 800 ML. This change will occur in the Water Register at 12 noon on Thursday October 15, 2020.
Customers participating in the water trading market can monitor trade availability on the 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 2020/21 seasonal determination announcement will be released on Monday 2 November 2020.
- The risk of spill in the Murray system will be updated on Tuesday 10 November 2020.
The northern Victoria Resource Manager today updated 2018/19 seasonal determinations.
The Murray system moves from 94 per cent of high-reliability water shares (HRWS) to 100 per cent HRWS.
The Goulburn system and the Loddon system increase from 88 per cent HRWS to 93 per cent HRWS.
The seasonal determination in the Broken system increases from 24 per cent HRWS to 30 per cent HRWS.
The Campaspe system remains at 100 per cent HRWS and the Bullarook system remains at 100 per cent HRWS and 100 per cent of low‑reliability water shares (LRWS).
Resource Manager Mark Bailey said recent rain helped to improve water availability.
“Most of northern Victoria received some rainfall during the first half of December,” said Dr Bailey.
“The rainfall across the northeast catchments increased the flows into the storages and in the downstream rivers,” said Dr Bailey. “The flows were higher than our conservative estimates, and together with lower evaporation from the storages, provided additional resource to allocate.”
Dr Bailey noted these factors will influence seasonal determination improvements in the coming months.
“The seasonal determination outlook to 15 February 2019 is based on historical flows into the major storages under different scenarios,” said Dr Bailey. “These flows are generally low at this time of year. Seasonal determination assessments include estimates of evaporation and river losses.
“As we have seen, if actual losses are lower than these estimates, more water is available to allocate.”
Dr Bailey noted the climate outlooks for summer rainfall did not favour wetter or drier conditions.
“The latest Bureau of Meteorology seasonal outlook indicates there is an even chance of receiving above average rainfall during the December to February period,” Dr Bailey said. “The Bureau has issued an El Niño Alert, meaning the chance of an El Niño forming in the coming months is around 70 per cent. It is likely that the positive Indian Ocean Dipole is nearing its end, but it has little influence on rainfall from December to April.”
Dr Bailey urged water users to continue planning their water needs carefully. “Websites such as the Resource Manager (www.nvrm.net.au), the Victorian Water Register (www.waterregister.vic.gov.au) and the Murray-Darling Basin Authority (www.mdba.gov.au) provide information about water trends and availability, which can help users plan their use.”
The seasonal determinations for northern Victorian water systems on Monday, December 17 are: