The Resource Manager for northern Victorian water systems today updated the outlook for the 2012/13 season.
From
the 2012/13 season onwards, the Resource Manager will refer to seasonal
determination in place of the term seasonal allocation. An allocation
is the volume of water available to entitlement holders. It is the total
of the water share volume multiplied by the seasonal determination,
plus any unused allocation carried over from last season, less usage,
plus the net of all allocation trades. Seasonal determination is the
percentage of water share volume available under current resource
conditions.
"Seasonal determinations are expected to be announced
for all systems on 2 July 2012 regardless of prevailing inflow
conditions," Resource Manager Dr Mark Bailey said. "The Campaspe system
is expected to start 2012/13 with a seasonal determination of 100% of
high-reliability water shares (HRWS). Increases to seasonal
determinations in the Murray, Goulburn, Loddon, and Broken systems are
expected, but will depend on inflows during the winter and spring."
"All
of the northern Victorian systems are expected to have seasonal
determinations of 100% HRWS by mid February 2013 under average inflow
conditions," said Dr Bailey.
"The total volume of unused
allocation at the end of 2011/12 is expected to be approximately 2,000
GL, which is about 400 GL lower than the volume carried over last
season," noted Dr Bailey. "The allocation carried over in the Broken,
Loddon and Bullarook systems is likely to be close to the maximum
available under the rules for those systems, and will contribute to
early season water availability."
"Current storage volumes and
carryover trends means that there will not be a declaration of low risk
of spill in the Murray, Goulburn and Campaspe systems during the first
few months of the 2012/13 season," said Dr Bailey. "In particular,
Murray system customers should not expect a declaration of a low risk of
spill at the start of the season, which has occurred in the past two
seasons."
"Seasonal determinations of low-reliability water
shares (LRWS) in the Murray, Goulburn and Loddon systems will depend on
usage of existing allocation 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, the
chances of seasonal determinations of LRWS improve," Dr Bailey added.
Further Detail on 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.
Murray System Outlook for Seasonal Determination of High-Reliability Water Shares
| Inflow Conditions |
2 July 2012 |
15 August 2012 |
17 October 2012 |
15 February 2013 |
| Wet |
42% |
62% |
100% |
100% |
| Average |
31% |
46% |
90% |
100% |
| Dry |
29% |
35% |
69% |
100% |
Goulburn & Loddon Systems Outlook for Seasonal Determination of High-Reliability Water Shares
| Inflow Conditions |
2 July 2012 |
15 August 2012 |
17 October 2012 |
15 February 2013 |
| Wet |
67% |
100% |
100% |
100% |
| Average |
58% |
85% |
100% |
100% |
| Dry |
48% |
61% |
80% |
99% |
Seasonal determinations in the Campaspe system are expected to be
100% of HRWS under all inflow scenarios on 2 July 2012. 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.
Further Detail on the Risk of Spill in the Murray, Goulburn and Campaspe Systems
There
will be large volumes of unused allocation at the end of the 2011/12
season in the Murray, Goulburn and Campaspe systems. Based on the volume
expected to be held in Victoria’s share of Dartmouth Reservoir, and the
volumes in Lake Eildon and Lake Eppalock at the end of 2011/12, there
is the potential for all three storages to spill in 2012/13.
Water
share holders should expect that water in spillable water accounts may
not be available until later in 2012, and should plan their early season
water use requirements accordingly. The first formal assessment of the
risk of spill for each system will be made at the start of the 2012/13
season.
Upcoming Resource Manager Announcements
The first
seasonal determinations for 2012/13 will be announced on Monday 2 July
2012, and will include an updated seasonal outlook.
For
information about the Resource Manager for northern Victorian regulated
water systems, including seasonal determinations and resource
availability, please visit
www.nvrm.net.au.