Irrigation Allocations - March 2011
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Irrigation demand across all systems remains relatively low due to the continuing rainfall. Allocations across Victoria remained unchanged throughout March.
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 will be on 1 April, no further changes are expected. |
| Goulburn | 100% | - | - | ||
| Campaspe | 100% | 100% | - | ||
| Broken | 100% | 100% | - | ||
| Loddon | 100% | - | - | ||
| Bullarook | 100% | 100% | - | ||
| Southern Rural Water | Werribee & Bacchus Marsh | 100% | 50% | +5% | Announced 22 February. |
| Macalister | 100% | 100% | +105% | Announced 22 February. | |
| Coliban Water | Coliban Rural System | 70% | - | - | Announced 15 September. |
| Grampians Wimmera Mallee Water | Wimmera Mallee Supply System | 100% | - | +19% | Announced 15 February. |
Goulburn-Murray Water (G-MW)
AllocatioAllocations on all northern systems remained unchanged throughout March. Demand during the month was low due to the wet conditions in northern Victoria.
Allocations against low-reliability shares in 2010/11 for the Goulburn and Murray systems remains unlikely, due to a combination of factors, including the large volume of water carried over from 2009/10, very low demand to date and the fact that all storages downstream of Lake Eildon and Dartmouth Reservoir are full and unable to contribute to the conservation of additional reserve. Inflows to Lake Eildon and Dartmouth Reservoir are contributing to the reserves in the Goulburn and Murray systems for the 2011/12 season, however reserves must be sufficient to deliver 100% allocation for HRWS next season before any low-reliability water shares can be allocated this season.
All northern systems have an allocation of at least 100% for high-reliability shares for the first time since 2001/02. Because of the 100% allocation for HRWS on all systems, allocation announcements have been made monthly instead of fortnightly since November. The final allocation announcement for the 2010/11 season will be made on 1 April.
Northern Victoria Seasonal Irrigation Outlook
Goulburn-Murray Water’s first outlook for the 2011-12 season was released on 15 February 2011 and is summarised below. This outlook will be updated on 16 May.
On 1 July 2011, a seasonal allocation is expected to be announced in both the Murray and Goulburn systems from the reserves set aside in recent months. With allocations likely to be made early in 2011/12, the channel systems will be available to deliver water from 15 August. Allocations in the Campaspe system are expected to be 100% of HRWS under all inflow scenarios on 1 July 2011. Under each inflow scenario, all systems would receive an allocation on Monday 15 August 2011.
There is likely to be an extremely high volume of unused allocation at the end of the 2010/11 season in the Murray, Goulburn and Campaspe systems given the record low deliveries this season. Victoria's share of Dartmouth Reservoir is likely to be above 60% of capacity, Lake Eildon is not expected to fall below 70%, and the volume in Lake Eppalock will remain close to full capacity. Based on current storage levels and expected operating conditions, the probability that Dartmouth Reservoir will spill in 2011/12 is low. However, there is a greater chance that Lake Eildon and Lake Eppalock will spill. It is too early for the Resource Manager to make a declaration about the availability of water in spillable water accounts in any system. An update will be provided with the next allocation outlook and the first formal assessment will be made at the start of the 2011/12 season.
.
Seasonal Irrigation Allocation Outlook 2011/12
Outlook for 1 July 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 32% | 47% | 47% | 100% | 20% |
| Average | 18% | 36% | 36% | 100% | 4% |
| Dry | 4% | 32% | 32% | 100% | 0% |
Outlook for 15 August 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 40% | 100% | 100% | 100% | 32% |
| Average | 32% | 52% | 52% | 100% | 24% |
| Dry | 7% | 38% | 38% | 100% | 7% |
Outlook for 17 October 2011
| Inflow Conditions | Murray | Goulburn | Loddon | Campaspe | Broken |
|---|---|---|---|---|---|
| Wet | 77% | 100% | 100% | 100% | 100% |
| Average | 53% | 92% | 92% | 100% | 100% |
| Dry | 36% | 46% | 46% | 100% | 36% |
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 | 66% | 64% | 64% | 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 is a full allocation against high- and low-reliability water shares in the MID this season. Continued rainfall and low demand to date means the volume of water in Lake Glenmaggie remains very high for this time of year.
The volume delivered under spill entitlement to 15 December 2010 was equal to approximately 32% of the district’s entitlement.
Latrobe System
The power stations’, GW’s and SRW’s shares of Blue Rock were at 100 per cent at the end of March. 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 March.
There is a 100% allocation for high-reliability shares, and a 50% allocation for low-reliability shares this season to date. A year ago allocations were 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. To date, the equivalent of about 45% allocation against HRWS has been set aside for next year.
Maribyrnong Basin
Storage levels in Rosslynne Reservoir decreased slightly over March, finishing the month at 66.0% of capacity. This time last year, Rosslynne Reservoir held just 4.5%.
SRW’s waterway diverters on Jackson Creek can access 50% of licensed volume, while Melbourne Water’s licence holders in the Keilor region continue to access unregulated flows downstream of Rosslynne Reservoir.