Irrigation Allocations - August 2011
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During August, Goulburn-Murray Water increased allocations on all northern systems except Bullarook which has already reached maximum allocation for the 2011/12 season. Even under projected dry conditions, allocations for the Goulburn, Loddon and Broken systems will reach 100% HRWS during spring. The Murray is expected to reach 100% by mid-December.
In southern Victoria, allocations on the Macalister system will remain at 90% until the end of the spilling period on 15 December. In the Werribee and Bacchus Marsh irrigation districts, allocations remained at 100% HRWS and 15% LRWS throughout August.
Surface Water Irrigation Allocations across Northern Victorian
| Water Corporation | System | HWRS Allocation | LRWS Allocation | % Change over the month | Comments |
|---|---|---|---|---|---|
|
Golburn Murray Water
|
Murray | 50% | - | +17 | G-MW made its first announcement on 1 August. Allocations increased on all systems except Bullarook with the second announcement on 15 August. Next announcement 1 September. |
| Goulburn | 78% | - | +18 | ||
| Campaspe | 100% | 54% | +7 | ||
| Broken | 34% | - | +14 | ||
| Loddon | 78% | - | +18 | ||
| Bullarook | 100% | 100% | - | ||
| Southern Rural Water | Werribee & Bacchus Marsh | 100% | 15% | - | Next announcement 6 September. |
| Macalister Irrigation District | 90% | - | - | Next announcement 15 December. River diverters can access spill entitlement until 1 August. | |
| Coliban Water | Coliban Rural System | TBA% | - | - | 2011/12 announcement due 15 September. |
| Grampians Wimmera Mallee Water | Wimmera Mallee Supply System | 0% | - | - | Announced 11 July. |
Goulburn-Murray Water (G-MW)
On 1 August, G-MW increased HRWS allocations from 60% to 69% on the Goulburn and Loddon systems; from 32% to 35% on the Murray system; and, from 20% to 25% on the Broken system. The LRWS allocation on the Campaspe system increased from 47% to 52%. The Bullarook system allocation has been 100% for both HRWS and LRWS since 15 July, and did not change.
In the second announcement on 15 August, allocation for HRWS was increased to 50% on the Murray, 34% on the Broken, and 78% on the Goulburn and Loddon systems. Allocations against low-reliability water shares were increased to 54% for the Campaspe system.
On 10 August, the Northern Victoria Resource Manager announced that the risk of spill in the Goulburn and Campaspe systems remains high, therefore, at this stage water held in spillable water accounts cannot be made available to customers. The next risk of spill announcement will be made on 12 September.
Northern Victoria Seasonal Irrigation Outlook
On 15 August 2011, Goulburn-Murray Water (G-MW) updated the seasonal allocation outlook for the 2011/12 season. The outlooks for 2011/12 allocations are based on observed inflows in seasons following similar early winter inflows.
As the Campaspe and Bullarook systems have already reached full allocations for high-reliability water shares (HRWS) (and have allocations against low-reliability water shares (LRWS)), no outlook is provided for these systems. In the Campaspe system, the allocation against low-reliability water shares is expected to reach 100% this season.
Even under dry conditions, the allocations in the Broken, Goulburn and Loddon systems are expected to reach 100% HRWS during spring (therefore Table 2 does not include an outlook for those systems).
Allocations against LRWS in the Murray, Goulburn and Loddon systems will depend on prevailing weather conditions. An allocation of LRWS in the Broken system is expected, with the timing dependent on seasonal conditions.
The next seasonal outlook will be released on 15 September 2011. To view the latest outlook click here.
Table 2 - Outlook for allocations against HRWS in the Murray System
| Inflow Conditions | 17 October 2011 | 15 December 2011 | 15 February 2011 |
|---|---|---|---|
| Wet | 89% | 100% | 100% |
| Average | 80% | 100% | 100% |
| Dry | 70% | 100% | 100% |
Wimmera Mallee Supply System
GWMWater did not make an allocation for irrigators on the Wimmera Mallee Supply System with its allocation announcement on 11 July. The Wimmera Irrigation Association is continuing to negotiate a sale of the irrigation entitlement to the Commonwealth Government, and the channel run has been deferred until the outcome of the sale is known. GWMWater has not delivered irrigation supplies for around 10 years.
Coliban Rural System
Coliban Water will announce its 2011/12 opening allocation in September 2011.
Southern Rural Water
Macalister Irrigation District (MID)
Demand has remained low for the beginning of the 2011/12 season. Lake Glenmaggie remains at a high level for this time of year, and Southern Rural Water have lowered the storage to mitigate downstream flooding risk over winter and spring, with a target to ensure the storage is filled before the commencement of the late-spring and summer period.
The season opened with a maximum allocation of 90% for HRWS, the highest possible allocation during the spilling season. Spill entitlement has been made available to river diverters until 15 August. The current allocation will be reviewed following the end of the spilling period on 15 December.
Latrobe System
The power stations’, GW’s and SRW’s shares of Blue Rock were at 100 per cent at the end of August. There is enough water in the system to supply power stations, industry and towns in the Latrobe Valley for the next 12 months even if conditions are dry.
Licence holders downstream on the Latrobe and Tanjil Rivers are permitted to take up to their licence volume.
Werribee Basin
SRW’s share of the Werribee storages was at 91% of capacity at the end of August.
Allocations remained at 100% for HRWS and 15% for LRWS throughout August.
Maribyrnong Basin
Storage levels in Rosslynne Reservoir increased slightly during August, finishing the month at 68.7% of capacity.
SRW’s waterway diverters on Jackson Creek can access 100% of licensed volume, while Melbourne Water’s licence holders in the Keilor region continue to access unregulated flows downstream of Rosslynne Reservoir.