Goulburn-Murray Water Releases 2010/11 Seasonal Allocation Outlook
Goulburn-Murray Water (G-MW), the resource manager for northern Victorian water systems, today released the first outlook for 2010/11 seasonal allocations.
Inflows to the regulated water systems in the 2009/10 season have remained well below average. The Murray and Goulburn systems have received the highest allocations since 2006/07 and 2005/06 respectively, but both remain well below the long term average for February due to these low inflows and the absence of any system reserves. The Broken and Bullarook systems have received their first allocations for two seasons, and the Campaspe and Loddon systems are unlikely to receive any allocation for the second consecutive year.
The worst case condition for 2010/11 would involve little resource improvement after the final allocation announcement for the 2009/10 season is made on 1 April 2010. In this case, all major storages would start the season with very low resources apart from private carryover, and water availability would depend exclusively on the inflows that occur during winter and spring.
With poor correlation between low summer inflows and winter and spring inflow conditions, G-MW has used the full inflow record available to assess the seasonal allocations 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
To assist customers to compare the outlook against current inflow conditions, the table below summarises the inflow conditions across the northern Victorian water systems since the start of the 2009/10 season:
Status of Inflows to Regulated Water Systems between July 2009 and February 2010
|
Water System |
Probability of Exceedance |
Description |
|
Murray |
90% |
Inflow volumes that have 90 chances in 100 of being exceeded |
|
Broken |
98% |
Inflow volumes that have 98 chances in 100 of being exceeded |
|
Goulburn |
86% |
Inflow volumes that have 86 chances in 100 of being exceeded |
|
Campaspe |
99% |
Inflow volumes that have 99 chances in 100 of being exceeded |
|
Loddon |
99% |
Inflow volumes that have 99 chances in 100 of being exceeded |
The Outlook for the Start of the 2010/11 Season
The 1 July 2010 seasonal allocation is expected to be zero in all systems under dry and average inflow conditions. Small allocations would be possible in some systems if wet conditions were dominant.
Average inflow conditions would provide for the announcement of non-zero allocations on Monday 16 August 2010. Persisting drought conditions, such as those experienced since 2006/07, would provide a small allocation in the Murray system, but prevent an allocation in all other systems.
Outlook for 16 August 2010 Seasonal Allocations (Percentage of high-reliability water share)
|
Inflow Conditions |
Murray |
Broken |
Goulburn |
Campaspe |
Loddon |
|
Wet |
69% |
86% |
73% |
100% |
100% |
|
Average |
33% |
2% |
33% |
41% |
91% |
|
Dry |
6% |
0% |
0% |
0% |
0% |
Spring 2010/11
Allocations for the 2010/11 season will be defined by the inflows that occur between July and October 2010, which has historically been the period of highest inflows. Near average conditions will translate into substantial allocation improvements for all systems, but a dry winter and spring will see allocations remaining at the zero or low levels experienced in recent years.
Outlook for 15 October 2010 Seasonal Allocations (Percentage of high-reliability water share)
|
Inflow Conditions |
Murray |
Broken |
Goulburn |
Campaspe |
Loddon |
|
Wet |
100% |
97% |
100% |
100% |
100% |
|
Average |
62% |
92% |
65% |
100% |
100% |
|
Dry |
24% |
0% |
31% |
0% |
17% |
The February 2011 Allocation Outlook
The 15 February allocation in any season is regarded as the best indicator of the highest allocation to be announced in a given season. The outlook for the 2011 allocation is summarised below.
Outlook for 15 February 2011 Seasonal Allocations (Percentage of high-reliability water share)
|
Inflow Conditions |
Murray |
Broken |
Goulburn |
Campaspe |
Loddon |
|
Wet |
100% |
100% |
100% |
100% |
100% |
|
Average |
100% |
100% |
100% |
100% |
100% |
|
Dry |
48% |
0% |
43% |
6% |
47% |
G-MW will update the allocation outlook on Monday 17 May 2010. The first 2010/11 seasonal allocation announcement will be released on Thursday 1 July 2010.
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Media Contact: Graeme Hannan
Position: Executive Manager Water Resources
Telephone: (03) 5833 5498
