Seasonal Determinations for 2012/13 Updated

Determination Data

Seasonal determinations for northern Victoria regulated river systems.

Further Information

The Resource Manager for northern Victorian regulated water systems today announced an update to the seasonal determinations for the 2012/13 season.

The Murray system seasonal determination is 34% of high-reliability water shares (HRWS), an increase of 8%. The seasonal determination in the Goulburn and Loddon systems has increased by 13% to 74% HRWS. The Broken system seasonal determination has increased by 4% to 22% HRWS. Campaspe system customers have a seasonal determination of 100% HRWS.

The Bullarook system seasonal determination has increased from 14% HRWS to be 100% HRWS and 100% of low-reliability water shares (LRWS).

"The improvements in the seasonal determinations for the Murray and Goulburn systems resulted from higher than anticipated inflows," said Dr Mark Bailey, Resource Manager. "The catchments in northern Victoria responded well to recent rainfall. There was an excellent response in the Bullarook Creek catchment, which allowed a large improvement to the determination in that system."

"There has been approximately 80,000 megalitres released from Lake Eildon since 1 July under pre-release conditions," said Dr Bailey. "This has caused the volumes held in Goulburn spillable water accounts, the Goulburn inter-valley trade account, and Living Murray environmental entitlements to be debited."

"The Lake Eildon releases are continuing, so additional volumes will be debited from the three accounts at the next seasonal determination update," added Dr Bailey. "No spills have occurred from Lake Dartmouth or Lake Eppalock, but both storages have risen after rainfall and inflows over the last fortnight."

Outlook for the 2012/13 Season

The Resource Manager has used the full inflow record available to assess seasonal determinations for a range of inflow scenarios. The scenarios for different inflow conditions have been produced using the following terminology:

Wet - Inflow volumes that have 10 chances in 100 (or 1 chance in 10) of being exceeded
Average - Inflow volumes that have 50 chances in 100 (or 5 chances in 10) of being exceeded
Dry - Inflow volumes that have 90 chances in 100 (or 9 chances in 10) of being exceeded

The following tables summarise possible seasonal determinations in the Murray, Goulburn and Loddon systems through the 2012/13 season.

In the Broken system, customers are expected to receive a seasonal determination of 100% HRWS by 15 February 2013 under dry conditions. Under average conditions, the seasonal determination is expected to reach 100% HRWS during spring. Low-reliability water shares are also expected to receive a seasonal determination of 100% in late spring under average conditions.

"Seasonal determinations of low-reliability water shares (LRWS) in the Murray, Goulburn and Loddon systems will depend on usage and the volume of inflows during winter and spring. If inflows result in water being debited from spillable water accounts and water is used during periods of unregulated flows without release from storage, the chances of seasonal determinations of LRWS improve," said Dr Bailey.

Under average conditions in the Campaspe system, customers are expected to receive a seasonal determination of 100% LRWS by 15 October.

Summary of Seasonal Determinations

The seasonal determinations for northern Victorian water systems on Monday 16 July 2012 are detailed at the top of the page.

Customers participating in the water trading market are reminded that the Murray-Darling Basin Authority has relaxed the rule controlling allocation trade from upstream of the Barmah Choke to downstream users. The ability to trade across the Barmah Choke will be regularly reviewed by the Murray-Darling Basin Authority and the relaxation may be lifted at any time during the season.

Upcoming Resource Manager Announcements

The next seasonal determination announcement for 2012/13 will be issued on Wednesday 1 August 2012.

The next assessment of the probability of spill in the Murray, Goulburn and Campaspe systems will be issued on Friday 10 August 2012.

For information about the Resource Manager for northern Victorian regulated water systems, including seasonal determinations and resource availability, please visit www.nvrm.net.au.