Irrigation Allocations - June 2011
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The final allocation announcement for the northern Victorian systems was made on 1 April, with no changes to allocations. There were no changes to allocations in southern Victorian systems during June. The 2010/11 season finished with full allocations on all of Victoria’s major irrigation systems.
The 2011/12 season commences on 1 July with opening allocation announcements from Southern Rural Water and Goulburn-Murray Water. Thanks to an above average year of inflows during 2010/11, starting allocations are expected on all major irrigation systems.
Surface Water Irrigation Allocations across Northern Victorian
| Water Corporation | System | HWRS Allocation | LRWS Allocation | % Change over the month | Comments |
|---|---|---|---|---|---|
|
Golburn Murray Water
|
Murray | 100% | - | - | Final announcement for the season was made on 1 April (no changes). |
| Goulburn | 100% | - | - | ||
| Campaspe | 100% | 100% | - | ||
| Broken | 100% | 100% | - | ||
| Loddon | 100% | - | - | ||
| Bullarook | 100% | 100% | - | ||
| Southern Rural Water | Werribee & Bacchus Marsh | 100% | 55% | +5% | Announced 19 April. |
| Macalister Irrigation District | 100% | 100% | - | Announced 22 February. | |
| Coliban Water | Coliban Rural System | 70% | - | - | Announced 15 September. |
| Grampians Wimmera Mallee Water | Wimmera Mallee Supply System | 100% | - | - | Announced 15 February. |
Goulburn-Murray Water (G-MW)
For the 2010/11 season, all northern systems had an allocation of at least 100% for high-reliability water shares for the first time since 2001/02. The 2011/12 season will commence on 1 July 2011. Goulburn-Murray Water updated the outlook for the 2011/12 season on 16 May 2011.
Northern Victoria Seasonal Irrigation Outlook
On 1 July 2011, a seasonal allocation is expected to be announced for high-reliability water shares (HRWS) in all systems, under all inflow conditions. With allocations early in 2011/12 likely, the channel networks will be available to deliver water from 15 August in the Murray and Goulburn systems.
The Campaspe system is anticipated to open the 2011/12 season with a 100% allocation for HRWS, and a 100% allocation for low-reliability water shares (LRWS) is expected under all but the driest scenarios. Allocations against LRWS are also expected in the Broken system, with the timing dependent on seasonal conditions.
Allocations against LRWS in the Murray, Goulburn and Loddon systems are possible during 2011/12, however the magnitude and timing will depend on the prevailing seasonal conditions.
Demand in the Murray, Goulburn and Campaspe systems during 2010/11 has been exceptionally low. This has kept storage levels high throughout much of the season. Lake Eppalock is currently above 97% of capacity, Lake Eildon is at 84% and Victoria's share of Dartmouth Reservoir is approximately 65% of capacity. Based on current conditions, the probability that Dartmouth Reservoir will spill in 2011/12 is low, but there is a higher potential for Lake Eildon and Lake Eppalock to spill. Under a continuation of current conditions, it is likely that a declaration of low spill probability will be made for the Murray system on 1 July 2011, but a declaration for the Goulburn and Campaspe systems will most likely occur later in the season.
A definitive comment on spill declarations for 2011/12 will be made on 1 July 2011, when G-MW announces the opening seasonal allocations.
High Reliability Allocation Outlook 2011/12 at 15 May
Outlook for 1 July 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 47% | 68% | 68% | 100% | 18% |
| Average | 43% | 48% | 48% | 100% | 18% |
| Dry | 40% | 43% | 43% | 100% | 18% |
Outlook for 15 August 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 61% | 100% | 100% | 100% | 22% |
| Average | 49% | 80% | 80% | 100% | 22% |
| Dry | 44% | 53% | 53% | 100% | 22% |
Outlook for 17 October 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 100% | 100% | 100% | 100% | 41% |
| Average | 83% | 100% | 100% | 100% | 41% |
| Dry | 67% | 74% | 74% | 100% | 41% |
Outlook for 15 February 2012
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 100% | 100% | 100% | 100% | 100% |
| Average | 100% | 100% | 100% | 100% | 100% |
| Dry | 100% | 96% | 96% | 100% | 100% |
Wimmera Mallee Supply System
GWMWater increased the irrigation allocation to 100% during February, however the irrigation channel run has been deferred this season, following consultation with the Wimmera Irrigators and Diversions Committee. 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 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. However, there is little demand for water in the rural system given the wet conditions.
Southern Rural Water
Macalister Irrigation District (MID)
There was a full allocation against high- and low-reliability water shares in the MID for the 2010/11 season. Continued rainfall and low demand to date means the volume of water in Lake Glenmaggie remains very high for this time of year. Southern Rural Water has commenced releases to mitigate downstream flooding risk over winter and spring.
The current storage position provides a platform for a very good season in 2011/12.
Latrobe System
The power stations’, GW’s and SRW’s shares of Blue Rock were at 100 per cent at the end of June. 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 87% of capacity at the end of June.
The 2010/11 season finished with a 100% allocation for high-reliability shares, and a 55% allocation for low-reliability shares. This is significantly better than the 2009/10 season, when allocations finished at just 14% of high-reliability shares.
The wet conditions have reduced demand in the two irrigation districts considerably. SRW does not expect irrigators to substantially use their allocations by the end of the year and the starting allocation for 2011/12 is likely to be high compared to recent years.
SRW has implemented a new reserve policy in 2010/11 that will support starting allocations in 2011/12, which are expected to be high.
Maribyrnong Basin
Storage levels in Rosslynne Reservoir decreased slightly over June, finishing the month at 65.9% of capacity. This time last year, Rosslynne Reservoir held just 4.6%.
SRW’s waterway diverters on Jackson Creek can now access 100% of licensed volume, while Melbourne Water’s licence holders in the Keilor region continue to access unregulated flows downstream of Rosslynne Reservoir.