Seasonal determination update for 2017/18

Monday 16 October, 2017

The Resource Manager for northern Victoria today updated the 2017/18 seasonal determinations.

The Goulburn system and the Loddon system both increase from 81 per cent to 91 per cent high-reliability water shares (HRWS).

The low-reliability water share (LRWS) seasonal determination in the Campaspe system increases from 24 per cent to 29 per cent. The Campaspe system also has 100 per cent HRWS.

The Broken system increases from 41 per cent to 50 per cent HRWS.

The seasonal determination in the Murray system remains unchanged 100 per cent HRWS and the Bullarook system remains at 100 per cent HRWS and 100 per cent LRWS.

Resource Manager Mark Bailey said good flows continued in all systems despite low rainfall in recent weeks.

“Stream flows have remained higher than expected since the last seasonal determination update,” Dr Bailey said.

“This, together with recent use which reduces delivery commitments, has contributed to the increased seasonal determinations announced today.”

In the Murray system, the Resource Manager has continued to repay water borrowed from the Barmah Forest account.

“Water was borrowed from the Barmah Forest to improve early seasonal determinations for Murray system high-reliability water shares,” Dr Bailey said.

“Low-reliability water share assessments for the Murray system will start when all the borrowed water in the Murray system is repaid. The remaining balance is 64 gigalitres.”

Dr Bailey confirmed that Victoria could not store all the flows into its share of Lake Hume during September.

“Victoria’s share of Lake Hume remained full during September and 70 gigalitres of flow into the reservoir could not be stored. About 33 per cent of the spillable volume will be deducted proportionally from Murray system spillable water accounts and environmental water accounts,” Dr Bailey said.

“Further deductions from Murray system spillable water accounts and environmental water accounts are possible this season."

The seasonal determinations for northern Victorian water systems on Monday, October 16 are:

 

Water System High-Reliability Water Share Low-Reliability Water Share
Murray 100% 0%
Broken 50% 0%
Goulburn 91% 0%
Campaspe 100% 29%
Loddon 91% 0%
Bullarook 100% 100%

 

Outlook for the 2017/18 season

The Resource Manager uses historical flow records to assess the seasonal determinations for a range of inflows to the major storages. The scenarios are:

Wet                Inflow volumes to major storages that are greater in 10 years out of 100
Average         Inflow volumes to major storages that are greater in 50 years out of 100
Dry                 Inflow volumes to major storages that are greater in 90 years out of 100
Extreme Dry  Inflow volumes to major storages that are greater in 99 years out of 100

The following tables summarise possible high-reliability water share seasonal determinations through the season and include a reference year to help users recognise the possible inflow conditions.

Goulburn and Loddon System Outlook for Seasonal Determination of High-Reliability Water Shares


Inflow Conditions                       Similar inflow season             15 December 2017               15 February 2018
Wet                                                     2016/17                                   100%                                           100%
Average                                              2005/06                                   100%                                           100%
Dry                                                      2015/16                                   98%                                             100%
Extreme Dry                                       2006/07                                    92%                                             94%

Broken System Outlook for Seasonal Determination of High-Reliability Water Shares


Inflow Conditions                     Similar inflow season             15 December 2017                   15 February 2018
Wet                                                       2016/17                                       100%                                        100%
Average                                                2005/06                                       100%                                        100%
Dry                                                        2015/16                                       100%                                        100%
Extreme Dry                                          2006/07                                        50%                                          50%

Seasonal determinations under additional scenarios for each system are available from the Northern Victorian Resource Manager website at www.nvrm.net.au/outlooks

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 Murray system below 50 per cent. As the risk of spill in the Murray system is above 50 per cent, trade from New South Wales to Victoria is limited to the volume traded from Victoria to New South Wales. Trading opportunities are next updated on November 10, 2017.

The Goulburn system’s inter-valley trade (IVT) account owes about 259 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.

Customers participating in the water trading market can monitor trade availability on the Water Register website, http://www.waterregister.vic.gov.au/water-trading/allocation-trading Customers can monitor trading opportunities across the Barmah Choke on the Murray-Darling Basin Authority website at http://www.mdba.gov.au/managing-water/water-markets-trade/barmah-choke-trade-restriction

Upcoming Resource Manager Announcements


• The 2017/18 seasonal determinations are updated on Wednesday November 1, 2017.
• The risk of spill in the Murray and Campaspe systems is updated on Friday November 10, 2017