Irrigation Allocations - September 2010
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Goulburn-Murray Water (G-MW)
Goulburn-Murray Water announced increased allocations on all northern systems on 1 September. Allocations for high-reliability shares were increased to: Murray (57%), Broken (100%), Goulburn (41%), Campaspe (90%), Loddon (41%). On the Bullarook system, a 100% allocation against low reliability water shares was announced. This is the first time the Bullarook system has received the maximum possible allocation since the 2005/06 season.
On 15 September, Goulburn-Murray Water announced increases on the Murray (94%), Goulburn (67%), Loddon (67%) and Campaspe (100%). This is the highest allocation on the Campaspe system since 2004/05. The improvements were a result of the significant increase in inflows due to the high rainfall event at the start of September. However, resource improvements slowed as floods receded and rainfall was low in the second half of the month.
Once the Goulburn system allocation reached above 30%, G-MW started to build a reserve for the 2011/12 season’s system operating requirements. When the Goulburn system allocation exceeded 50% HRWS on 15 September, G-MW had established the 2011/12 reserve. Any inflows after 15 September will now be directed towards allocation improvements. The establishment of the reserve provides some certainty for operations next season.
The next allocation announcement will be made on 1 October 2010.
Irrigation Allocations across Northern Victorian
| Allocations at 1 September 2010 | LRWS Allocation | % Change over the month | |
|---|---|---|---|
| Goulburn | 67% | - | +41% HRWS |
| Murray | 94% | - | +71% HRWS |
| Broken | 100% | - | +79% HRWS |
| Campaspe | 100% | - | +10% HRWS |
| Loddon | 67% | - | +41% HRWS |
| Bullarook | 100% | 100% | +100% HRWS |
Temporary qualification of rights to water remained in place in the Murray, Goulburn, Broken, Campaspe and Loddon systems at the end of September, to ensure there is enough water available for essential urban and farming needs.
Seasonal Allocation Outlook for Northern Victoria – 2010/11
G-MW released the latest seasonal allocation outlook for the 2010/11 season on 15 September 2010. The outlook has been updated on the basis of recent resource improvements across northern Victoria. Outlooks are no longer produced for systems with 100% allocation against high-reliability shares.
Wet inflow conditions = Inflow volumes that have 1 chance in 10 of being exceeded. Average inflow conditions = Inflow volumes that have 5 chances in 10 of being exceeded. Dry inflow conditions = Inflow volumes that have 9 chances in 10 of being exceeded.
G-MW will make the next seasonal allocation outlook for the 2010/11 season on 15 October 2010.
Outlook for 15 October 2010
| Inflow Conditions | Murray | Goulburn | Loddon |
|---|---|---|---|
| Wet | 100% | 100% | 100% |
| Average | 100% | 99% | 99% |
| Dry | 100% | 78% | 78% |
Outlook for 15 December 2010
| Inflow Conditions | Murray | Goulburn | Loddon |
|---|---|---|---|
| Wet | 100% | 100% | 100% |
| Average | 100% | 100% | 100% |
| Dry | 100% | 95% | 95% |
Outlook for 15 February 2011
| Inflow Conditions | Murray | Goulburn | Loddon |
|---|---|---|---|
| Wet | 100% | 100% | 100% |
| Average | 100% | 100% | 100% |
| Dry | 100% | 100% | 100% |
Coliban Rural System
Coliban Water announced a 70% allocation for the 2010/11 season for the Coliban Rural System on 15 September. This is the highest allocation on the Coliban Rural System since 2002/03.
Wimmera Mallee Supply System
The Wimmera-Mallee Pipeline Project was officially completed in May 2010. All rural customers and towns connected to the pipeline are on Stage 1 restrictions.
Grampians Wimmera Mallee Water (GWMWater) announced a 30% irrigation allocation for Wimmera Mallee irrigators on 1 September. GWMWater has not delivered irrigation supplies for around 10 years. GWMWater will undertake maintenance and reinstate channels as necessary based on advice from irrigators before the summer irrigation period.
Southern Rural Water
Macalister Irrigation District (MID)
At the end of September, Lake Glenmaggie, the main source of water for the MID, was at 96.0% of capacity.
Macalister irrigators were able to access spill entitlement until 24 September. The allocation remains at 90%; any water delivered after 24 September is deducted from the irrigators’ allocation. The next allocation announcement will be on 15 December 2010 when the spilling period ends.
The current volume in the Thomson/Macalister irrigators’ Thomson drought reserve is 20,877 ML.
The current allocation and inflows provide a good platform for Macalister irrigators during the 2010/11 season.
Latrobe System
At the end of September, the storage level in Blue Rock Lake was 88.8% of capacity.
The irrigation share of Blue Rock was 2,239 ML. SRW licence holders downstream on the Latrobe and Tanjil Rivers can pump up to their licence volume, but this is subject to the availability of unregulated river flows (which normally contribute approximately 70% of entitlements). Irrigators have access to return flows from industry, which provides a secure source of water supplementing the run of river and volume in store.
Werribee Basin
SRW’s share of the Werribee storages was at 49% of capacity at the end of September.
Southern Rural Water increased allocations against high-reliability shares for the Werribee and Bacchus Marsh districts to 60% on 8 September as a result of inflows to storages following good rainfall in August and early September. The allocation was increased to 63% on 21 September. This is the highest allocation since 2005/06. This time last year, allocations were 2% of high-reliability shares, only guaranteed for delivery until 30 November.
In addition, SRW has been able to reserve water for the 2011/12 season, equivalent to a 13% allocation.
As a result of the improved conditions and allocations, it is possible that the Werribee irrigators’ strong reliance on recycled water will be eased this season. The recycling scheme has been providing about 68 ML/day shared between 90% of Werribee growers. The ban on groundwater use from the Deutgam Groundwater Management Area continues in 2010/11.
The Government announced on 16 March that Werribee and Bacchus Marsh irrigators would be able to access up to 5 GL of Melbourne’s water as a drought contingency measure. Metropolitan water will be offered to customers in the coming season, however, SRW is not expecting a high uptake, particularly in the Werribee irrigation district, due to the high cost of the water and the improved conditions for 2010/11 to date.
Maribyrnong Basin
The storage volume in Rosslynne Reservoir remains very low despite a small improvement in early September. At the end of September Rosslyne was at 13.5% of capacity (compared to 4.5% this time last year). Due to the continued low inflows, licensed diverters face another season with a zero allocation.