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October allocations for the 2026/27 water year.
Well below average monthly rainfall was recorded at all headworks sites across the Grampians during September. These conditions limited catchment flow and restricted inflow across the month. Residual rundown in the system and some rainfall was sufficient to generate 18,586 ML of inflow to storages during September, a reduction from the 42,558 ML recorded during August. A significant rainfall event did occur between 2nd and 3rd of October which was not captured in the inflow calculations but did contribute meaningful volumes of inflow to some storages.
Net evaporation increased during September with 4,660 ML recorded, a significant increase from the -2,270 ML calculated in August.
These improvements were sufficient to increase Wimmera-Mallee Pipeline Product entitlement allocations from 65% to 81%. Allocations were also made to Glenelg Compensations Flow (25%), Recreation (20%) and Wetlands (25%). 24.5 GL has also been allocated to the early system reserve. No allocation was possible to the Commonwealth Environmental entitlement.
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With criteria for the Storage Manager to consider a Rocklands Reservoir to Toolondo Reservoir transfer being satisfied, the Storage Manager has completed an assessment of the likely impacts on the system using the guiding principles described in the Storage Management Rules.
These guiding principles were applied to the current and projected short-term conditions of both storages to determine if a transfer of either 5,000 ML or 10,000 ML would provide a positive outcome for both storages and entitlement holders in the system.
Key notes from the assessment are:
- Although models indicate some minor evaporative savings by either transfer volume, these saving were wholly negated by the volume projected to be lost to dead storage and transfer losses.
- Any volume transferred to Toolondo Reservoir is not expected to reduce the salinity in the lake, to the point where the water could be extracted and utilised by known demands (potential to reduce from 4,000 EC to 2,700 EC). Therefore, the volume of water was considered lost to the system from a supply point of view.
- The loss of transferred water through channel losses and to dead storage would likely result in a reduction in the volume of available water calculated for the Wimmera Glenelg Headworks System. This is likely to cause a reduction in potential entitlement holder allocation and does not support entitlement holder reliability or access to water.
- It is acknowledged that Toolondo Reservoir still holds some recreational and environmental values which would benefit from a water transfer. While these are important they are not prioritised above entitlement holder reliability and access to water.
Considering the above, a water transfer from Rocklands Reservoir to Toolondo Reservoir is not supported at this time. This may be reconsidered if the resource position of Rocklands Reservoir materially changes over the next few months.
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September allocations for the 2026/27 water year.
Close to average monthly rainfall received to storages across the Grampians was sufficient to generate 42,558ML of inflow to storages. Net evaporation also contributed to a resource improvement with -2,270 ML in net evaporation calculated for system storages.
These improvements were sufficient to increase Wimmera-Mallee Pipeline Product entitlement allocations from 23% to 65%. Allocations were also made to Glenelg Compensations Flow (9%), Recreation (7%) and Wetlands (8%). 20 GL has also been allocated to the early system reserve. No allocation was possible to the Commonwealth Environmental entitlement.
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August allocations for the 2026/27 water year.
Although rainfall was below the monthly average, it was sufficient to generate 28,301ML of inflow to storages. Net evaporation also contributed to a resource improvement with -920 ML in net evaporation calculated for system storages.
These improvements were sufficient to increase allocations from 12% to 23% for Wimmera-Mallee Pipeline Product entitlements. 20 GL has also been allocated to the early system reserve. No allocation was possible to Glenelg River Compensation Flow, Recreation, Wetland and Commonwealth Environmental entitlements.
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July allocations represent the opening allocations for the 2026/27 water year.
Above average rainfall during June was sufficient to generate 24,469 ML of inflow to storages and represented the highest inflow month of the 2025/26 water year. Net evaporation also contributed to a resource improvement with -3,280 ML in net evaporation calculated for system storages.
These improvements were sufficient to post an opening allocation of 12% to Wimmera-Mallee Pipeline Product entitlements. 11 GL was also allocated to the early system reserve. No allocation was possible to Glenelg River Compensation Flow, Recreation, Wetland and Commonwealth Environmental entitlements.
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June allocations for the 2025/26 water year have been announced by the Storage Manager.
Above average rainfall during May was sufficient to generate 1,937 ML of inflow to storages and contribute -2,390 ML in net evaporation to the system.
These improvements in addition to an evaporative saving in resource model provided a 6% increase to Wimmera-Mallee Pipeline Product (WMPP) entitlements, which increased to 40% allocation. The Glenelg River Compensation Flow remained at 1% allocation, and no allocation was possible to Recreation, Wetland and Commonwealth Environmental entitlements.
The June resource assessment is the last assessment for the 2025-26 water year. The next assessment will be opening allocations due on 1st July 2026.
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May allocations for the 2025/26 water year have been announced by the Storage Manager.
Below average rainfall during April limited inflow to storages with only 125 ML being recorded.
Evaporative saving during April provided a small 1% increase to Wimmera-Mallee Pipeline Product (WMPP) entitlements, which increased to 34% allocation. The Glenelg River Compensation Flow remained at 1% allocation, and no allocation was possible to Recreation, Wetland and Commonwealth Environmental entitlements.
Future increasing in allocation will be contingent on new water entering the system through inflow or realised evaporative / transfer losses on the system less than the assessment provision.
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April allocations for the 2025/26 water year have been announced by the Storage Manager.
A low-pressure system impacted Victoria between 27th February, and 2nd March providing some moderate falls to headwork storages. Although this system provided some moderate rainfall totals to the system, dry conditions throughout March resulted in limited inflow being recorded to system storages over the assessment period. The most significant benefit received from the rainfall was the offsetting impact it had on storage evaporation over the month. This saving provided a small 1% increase to Wimmera-Mallee Pipeline Product (WMPP) entitlements, which increased to 33% allocation. The Glenelg River Compensation Flow remained at 1% allocation, and no allocation was possible to Recreation, Wetland and Commonwealth Environmental entitlements.
Future increasing in allocation will be contingent on new water entering the system through inflow or realised evaporative / transfer losses on the system less than the assessment provision.
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March allocations for the 2025/26 water year have been announced by the Storage Manager.
A low-pressure system impacted Victoria between 27th February, and 2nd March providing some moderate falls to headwork storages. Although this system provided some moderate rainfall totals to the system, dry conditions throughout February resulted in limited inflow being recorded to system storages over the assessment period. Inflow received and evaporative saving realised during the assessment period provided a 4% increase to Wimmera-Mallee Pipeline Product (WMPP) entitlements, which increased to 32% allocation. Additionally, the Glenelg River Compensation Flow received 1% allocation. No allocation was possible to Recreation, Wetland and Commonwealth Environmental entitlements.
Future increasing in allocation will be contingent on new water entering the system through inflow or realised evaporative / transfer losses on the system less than the assessment provision.
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February allocations for the 2025/26 water year have been announced by the Storage Manager.
Limited inflow and high evaporative losses from storages during the resource period limited any improvement in the overall resource position. Wimmera-Mallee Pipeline Product (WMPP) entitlements remain at 28% allocation. Additionally, no allocation was possible to Glenelg River Compensation Flow, Recreation, Wetland and Commonwealth Environmental entitlements.
Future increasing in allocation will be contingent on new water entering the system through inflow or realised evaporative / transfer losses on the system less than the assessment provision.