2011/12 Risk of Spill Announcements

12 December 2011 - Declaration of Low Risk of Spill for Goulburn and Campaspe Systems

The Resource Manager for northern Victorian regulated water systems today announced that water held in spillable water accounts (SWA) in the Goulburn and Campaspe systems is now available for use or trade following the declaration of a low risk of spill in both systems.

"Over the past month, the combined effect of decreasing inflows and increased releases at Lake Eildon and Lake Eppalock has been enough to confirm that there is now a low risk of spill in the remainder of this season in the Goulburn and Campaspe systems," said Dr Mark Bailey, Resource Manager. "Water share holders who have water in SWAs will now have the remaining balance of their SWAs returned to their Allocation Bank Accounts for immediate use or trade."

"The risk of spill is considered to be low when the probability of filling during the season is less than 1 chance in 10," explained Dr Bailey. "This is a statistical assessment, which means it is still possible for Lake Eildon or Lake Eppalock to fill later this season. Customer accounts will not be affected should this happen. However, we must be clear that today's declaration is about the availability of allocated water resources and not a statement about the potential for flooding this season."

10 November 2011 - No Change to Goulburn and Campaspe Risk of Spill in November

The Resource Manager for northern Victorian regulated water systems today confirmed that the risk of spill in the Goulburn and Campaspe systems remains high in November.

"Lake Eildon and Lake Eppalock are both close to capacity, so there is still the potential for releases to be made above the minimum operating requirements" said Dr Mark Bailey, Resource Manager. "It is not possible to declare that the risk of spill in the Goulburn and Campaspe systems is low at this time. The ability to declare a low risk of spill will depend on demand from stored resources over the coming months in the Goulburn and Campaspe systems."

Goulburn System - Risk of Spill from Lake Eildon

While Lake Eildon remains close to full at this time of the year, the risk of spill remains high and water held in Spillable Water Accounts cannot yet be accessed. The volume of water released from Lake Eildon since 1 July 2011 under target filling arrangements is approximately 205,000 ML. Pre-releases have been made in recent days in anticipation of heavy rain. Pre-releases are treated as a spill, which reduces the volumes held in spillable water accounts, the Goulburn inter-valley trade account with the Murray system, and Living Murray entitlement accounts.

Campaspe - Risk of Spill from Lake Eppalock

The volume of water released above normal operating requirements from Goulburn-Murray Water's share of Lake Eppalock since it filled on 29 July 2011 is approximately 33,000 ML. Lake Eppalock is currently holding approximately 97% of capacity.

10 October 2011 - No Change to Goulburn and Campaspe Risk of Spill in October

The Resource Manager for northern Victorian regulated water systems today confirmed that the risk of spill in the Goulburn and Campaspe systems remains high in October.

"Releases above minimum requirements from Lake Eildon have not been required for the past six weeks, but there has been about 8,000 ML released from Goulburn-Murray Water's share of Lake Eppalock in that time" said Dr Mark Bailey, Resource Manager. "Further releases above the minimum operating requirements may be needed from Lake Eildon and Lake Eppalock to manage water levels in the coming months, as both storages remain close to capacity and recent rain has re-wet the catchments. It is not possible to declare that the risk of spill in the Goulburn and Campaspe systems is low at this time, and without a substantial change in storage volumes over the next couple of months, it may not be possible to make a declaration before December this year."

Goulburn System - Risk of Spill from Lake Eildon

While Lake Eildon remains close to full at this time of the year, the risk of spill remains high and water held in Spillable Water Accounts cannot yet be accessed. The volume of water released from Lake Eildon since 1 July 2011 under target filling arrangements is approximately 195,000 ML. Pre-releases were suspended on 27 August, but may be required as the storage slowly fills to capacity. Any pre-releases are treated as a spill, which reduces the volumes held in spillable water accounts, the Goulburn inter-valley trade account with the Murray system, and Living Murray entitlement accounts.

Campaspe - Risk of Spill from Lake Eppalock

The volume of water released above normal operating requirements from Goulburn-Murray Water's share of Lake Eppalock since it filled on 29 July 2011 is approximately 27,000 ML. Lake Eppalock is at 100% of capacity and spilling at low rates. These releases reduce the volumes held in spillable water accounts, the Campaspe inter‑valley trade accounts with the Murray and Goulburn systems, and Living Murray entitlement accounts.

12 September 2011 - No Change to Goulburn and Campaspe Risk of Spill in September

The Resource Manager for northern Victorian regulated water systems today confirmed that the risk of spill in the Goulburn and Campaspe systems remains high in September.

"Although releases above minimum requirements from Lake Eildon and Lake Eppalock have been suspended, both storages remain near capacity" said Dr Mark Bailey, Resource Manager. "Further releases from Lake Eildon and Lake Eppalock releases may be required to manage storage levels in the coming months. Thus, it is not feasible to make a declaration that the risk of spill in the Goulburn and Campaspe systems is low."

Goulburn System - Risk of Spill from Lake Eildon

The risk of spill from Lake Eildon continues to remain high whilst the storage remains close to full at this time of the year. The volume of water released from Lake Eildon since 1 July 2011 under target filling arrangements is approximately 195,000 ML. Pre-releases were suspended on 27 August, although if significant rainfall events occur in the coming months releases may be required under the target filling arrangements. Any pre-releases are treated as a spill, this results in a reduction of volumes held in spillable water accounts, the Goulburn inter-valley trade account with the Murray system, and Living Murray entitlement accounts.

Campaspe - Risk of Spill from Lake Eppalock

The volume of water released above normal operating requirements from Goulburn-Murray Water's share of Lake Eppalock since it filled on 29 July 2011 is approximately 24,300 ML. Lake Eppalock is near 100% of capacity, but not currently spilling. If higher inflows are received, releases above the normal operating requirements may be needed. These releases reduce the volumes held in spillable water accounts, the Campaspe inter‑valley trade accounts with the Murray and Goulburn systems, and Living Murray entitlement accounts.

10 August 2011 - No Change to Goulburn and Campaspe Risk of Spill in August

The Resource Manager for northern Victorian regulated water systems today confirmed that the risk of spill in the Goulburn and Campaspe systems remains high in August.

"Releases from Lake Eildon have continued since the risk of spill was last updated, and releases from Lake Eppalock are now above normal operating requirements because it reached capacity at the end of July," said Dr Mark Bailey, Resource Manager. "If the conditions experienced during recent months persist, the Lake Eildon and Lake Eppalock releases will continue for some time. Consequently, a declaration that the risk of spill in the Goulburn and Campaspe systems is low is not possible this month."

Goulburn System - Risk of Spill from Lake Eildon

Conditions experienced over the last three months, including the pre-releases that were conducted under target filling arrangements, demonstrate that the risk of spill from Lake Eildon is very high.

The volume of water released from Lake Eildon since 1 July 2011 under target filling arrangements is approximately 192,000 ML. The pre-releases, which are treated as a spill, reduce the volumes held in spillable water accounts, the Goulburn inter-valley trade account with the Murray system, and Living Murray entitlement accounts.

Campaspe - Risk of Spill from Lake Eppalock

The volume of water released above normal operating requirements from Goulburn-Murray Water's share of Lake Eppalock since it filled on 29 July 2011 is approximately 2,000 ML. As Lake Eppalock is full, any inflows above the normal operating requirements will be released downstream. Releases above these requirements reduce the volumes held in spillable water accounts, the Campaspe inter‑valley trade accounts with the Murray and Goulburn systems, and Living Murray entitlement accounts.

11 July 2011 - No Change to Goulburn and Campaspe Risk of Spill

The Resource Manager for northern Victorian regulated water systems today confirmed that there will be no change to the risk of spill in the Goulburn and Campaspe systems in July.

"The risk of spill in the Goulburn and Campaspe systems during 2011/12 remains very high, and a declaration for either system is not possible this month," said Dr Mark Bailey, Resource Manager. "Pre-releases from Lake Eildon started in late June in accordance with target filling procedures for the storage, and are expected to continue during July."

Goulburn System - Risk of Spill from Lake Eildon

The risk of spill from Lake Eildon is currently 100%. This assessment considers the current pre‑releases from the storage, and forecast inflows over the next six months based on existing catchment conditions.

The volume of water released from Lake Eildon since 1 July 2011 under pre-release arrangements is approximately 35,000 ML. The pre-releases, which are treated as a spill, reduce the volumes held in spillable water accounts, the Goulburn inter-valley trade account with the Murray system, and Living Murray entitlement accounts.

Campaspe - Risk of Spill from Lake Eppalock

The risk of spill from Lake Eppalock is currently 90%, considering forecast inflows for the next six months under current catchment conditions.

1 July 2011 - Risk of Spill Assessment for the Murray, Goulburn and Campaspe Systems

The risk of spill at Dartmouth Reservoir during 2011/12 is sufficiently small to allow the Resource Manager to declare a low risk of spill for the Murray system. Customers with allocation in spillable water accounts in the Murray system will have the volume returned to their allocation bank accounts for immediate use or trade.

A declaration is not possible for the Goulburn or Campaspe systems at this time. The probabilities of spill from Lake Eildon and Lake Eppalock are very high. Pre-releases from Lake Eildon started in late June in accordance with target filling procedures for the storage, and are expected to continue during July. The pre-releases at Lake Eildon mean that some spill from spillable water accounts is already occurring in the Goulburn system. The impact on Goulburn system spillable water accounts in the Goulburn system will be included in the 15 July seasonal allocation assessment.

“The probability of spill at Dartmouth Reservoir this season under current conditions was calculated to be less than 10%, which is the threshold for making a declaration,” said Dr Bailey. “The probabilities are far higher at Lake Eildon and Lake Eppalock, as both storages are holding a greater percentage of their capacity. The recently commenced Lake Eildon pre-releases are actually considered a spill in terms of spillable water accounts and will influence future allocations for the Goulburn system.”

The next assessment of the probabilities of spill in the Goulburn and Campaspe systems will be issued on Monday 11 July 2011. To clearly separate allocation and probability of spill announcements, details of spill probabilities will be released on the tenth day (or next business day) of each following month unless a declaration is made. No further assessments will be made for the Murray system.