Irrigation Allocations - August 2010
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Goulburn-Murray Water (G-MW)
On 2 August, G-MW made announced opening allocations for high-reliability shares on the Murray system (2%) and the Goulburn system (5%). This is the first time since 2005/06 that the Goulburn system has had a non-zero allocation at the start of August. The Murray system last had a non-zero early August allocation in 2006/07.
On 16 August, G-MW increased allocations on the Goulburn and Murray systems to 23% and 26% respectively. Opening allocations were announced on all other systems, including 21% on the Broken, 26% on the Loddon, 21% on the Campaspe and 100% on the Bullarook system. This was the first time since 2005/06 that all systems have had an allocation at the beginning of the season. The allocations announced on the Bullarook, Campaspe, and Loddon systems were also the highest allocations on these systems since 2005/06.
The next allocation announcement will be made on 1 September 2010.
Irrigation Allocations across Northern Victorian
| Allocations as at 31 August 2010 | % Change over the month | |
|---|---|---|
| Goulburn | 26% | +26% |
| Murray | 23% | +23% |
| Broken | 21% | +21% |
| Campaspe | 21% | +21% |
| Loddon | 26% | +26% |
| Bullarook | 100% | +100% |
In addition to the allocations, a record volume of water was carried over from the 2009/10 to the 2010/11 irrigation season on G-MW’s systems (see Table 2). The high volume of carryover has been attributed to late season increases in allocation on some systems in 2009/10, along with the introduction of Spillable Water Accounts and improved carryover rules on the Murray, Goulburn and Campaspe systems.
G-MW has declared that the probability of spill this season at Lake Eildon, Dartmouth Reservoir and Lake Eppalock is low. This means water held in customers’ Spillable Water Accounts will be made available in their Allocation Bank Accounts immediately.
Carryover Volumes across Northern Victoria
| Volume of Water Shares carried over to 2010/11 (GL) | 2010/11 carryover expressed as % HWRS | Volume carried over to 2009/10 (GL) | |
|---|---|---|---|
| Goulburn | 338 | 34% | 104 |
| Murray (GMW & LMW) | 457 | 38% | 174 |
| Broken | 4 | 22% | 2.5 |
| Campaspe | 1.1 | 3% | 1.3 |
| Loddon | 0.9 | 4% | 0.3 |
| Bullarook | 0.1 | 14% | 0 |
| Total | 875.43 | 282.1 |
Temporary qualification of rights to water remain in place in the Murray, Goulburn, Broken, Campaspe and Loddon systems this season to ensure there is enough water available for essential urban and farming needs. The qualification of rights to water on the Bullarook system has been revoked, as new bulk entitlements were created for this system in 2009 which include rules for managing water resources when storage levels are low.
Seasonal Allocation Outlook for Northern Victoria – 2010/11
G-MW released the latest seasonal allocation outlook for the 2010/11 season on 16 August 2010. The outlook has been updated on the basis of recent resource improvements across northern Victoria.
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 September 2010.
Outlook at 16 August 2010 (percentage of high-reliability water share)
Outlook for 15 October 2010
| Inflow Conditions | Murray | Broken | Goulburn | Campaspe | Loddon |
|---|---|---|---|---|---|
| Wet | 91% | 100% | 79% | 100% | 79% |
| Average | 73% | 100% | 56% | 80% | 56% |
| Dry | 59% | 0% | 40% | 23% | 40% |
Outlook for 15 December 2010
| Inflow Conditions | Murray | Broken | Goulburn | Campaspe | Loddon |
|---|---|---|---|---|---|
| Wet | 100% | 100% | 100% | 100% | 100% |
| Average | 100% | 100% | 86% | 94% | 86% |
| Dry | 63% | 85% | 46% | 27% | 46% |
Outlook for 15 February 2011
| Inflow Conditions | Murray | Broken | Goulburn | Campaspe | Loddon |
|---|---|---|---|---|---|
| Wet | 100% | 100% | 100% | 100% | 100% |
| Average | 100% | 100% | 100% | 100% | 100% |
| Dry | 82% | 94% | 52% | 28% | 52% |
Coliban Rural System
Coliban Water will announce the 2010/11 allocation for the Coliban Rural System on 15 September.
The Minister for Water has qualified rights to water in the Coliban rural system to allow Coliban Water to provide a 30% emergency supply to eligible commercial customers in the event that the general allocation is zero.
Wimmera Mallee Supply System
All towns and rural customers connected to the pipeline are on Stage 1 restrictions.
The official completion date of the pipeline was 28 May 2010 when all pipelines had been completed. Taylors Lake pumping station was still to be completed. These remaining works will be finished in August 2010.
The irrigation allocation was 0%.
Southern Rural Water
Macalister Irrigation District (MID)
At the end of August, Lake Glenmaggie, the main source of water for the MID, was at 92.4% of capacity.
On 10 August, Southern Rural Water increased the allocation for high reliability water shares to 80%, and again on 19 August to 90%. Spilling phase was declared on 19 August, and any water delivered from the start of the irrigation season (15 August 2010) until the end of the spilling period will be considered spill entitlement and will not be deducted from irrigators’ high reliability water shares.
The current volume in the Thomson/Macalister irrigators’ Thomson drought reserve is 20,237 ML.
The current allocation and inflows are a good start to the 2010/11 season for Macalister irrigators.
Latrobe System
At the end of August, the storage level in Blue Rock Lake was 85.0% of capacity.
The irrigation share of Blue Rock was 2,018 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 23% of capacity at the end of August.
Southern Rural Water increased allocations against high-reliability shares for the Werribee and Bacchus Marsh districts to 16% on 10 August. This was increased to 30% on 24 August. This is significantly better than previous years. For example, in August 2009, allocations were 2% of high-reliability shares, only guaranteed for delivery until 30 November. Although rainfall and river flows are still well below average, there has been relatively regular rainfall in the catchment to date which has produced minor river flows.
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 65 ML/day shared between 90% of Werribee growers. SRW are exploring the option of using river water to shandy with the recycled water, as well as options to run river water more regularly. 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 are not expecting a high uptake due to the high cost of the water and the improved conditions for 2010/11 to date.
Bacchus Marsh irrigators will rely heavily on carryover of allocation from last season, as well as emergency and metropolitan water supplies.
Maribyrnong Basin
The storage volume in Rosslynne Reservoir remained very low at 6.7% of capacity at the end of August. Licensed diverters will begin another season with zero allocation.