Irrigation Allocations - December 2007
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Goulburn-Murray Water (G-MW)
G-MW made allocation announcements on 3 December and 17 December. Although G-MW increased allocations on the Goulburn, Murray and Broken systems, they remain very low on all systems.
As of 17 December, allocations for high reliability water shares were as follows:
| 17th December 2007 | Change since 15 November 2007 | |
|---|---|---|
| Goulburn | 39% | 4% |
| Murray | 28% | 5% |
| Broken | 29% | 6% |
| Campaspe | 5% | 0% |
| Loddon | 5% | 0% |
| Bullarook | 0% | 0% |
In December, the Goulburn system allocation increased by 4% to 39%. This was due to small system efficiency gains and minor inflows following rainfall in early December.
G-MW increased the allocation in the Murray system by 5% to 28% supported by a combination of inflows, operational savings in the River Murray system and efficiency gains in Goulburn-Murray Water irrigation areas.
Following rainfall in early December, inflows to Lake Nillahcootie were the highest since July this year. Combined with operational savings, G-MW was able to increase the seasonal allocation on the Broken system by 6% to 29% on 17 December. The need for rostering of irrigation orders was also removed.
The seasonal allocation in the Campaspe and Loddon systems remained at 5% of high-reliability water shares during December. Irrigation orders were being rostered to minimise system losses.
There was not enough water in the Bullarook system for an irrigation allocation in December. No irrigation allocation is likely this season. Bullarook Creek customers continued to have access to water for domestic and stock purposes only.
G-MW released its latest forecast ranges for the final 2007/08 seasonal allocations on 17 December. Using inflows as a guide to the most likely summer inflows, the range of allocations are:
- 39% - 51% in the Goulburn system;
- 28% - 32% in the Murray system.
G-MW will provide further allocation announcements on 2 and 15 January 2008.
The Minister for Water approved the permanent introduction of carryover as a resource management measure. Under the severe drought conditions currently affecting northern Victoria, the Minister has also agreed that no allocations will be announced beyond 1 April 2008. All late season improvements will be retained as a contingency measure for water supplies in 2008/09.
Preparations for pumping Waranga Basin, under the recently announced Drought Relief Package, have commenced. Pumping is likely to commence in March 2008. The pumping program added 7% to the initial allocation for Goulburn system irrigators this season.
In June 2007, the Minister for Water temporarily qualified rights to water in the Murray, Goulburn, Broken, Campaspe, Loddon and Bullarook systems to make sufficient water available for essential urban and farming needs.
Normal allocation rules have resumed on the Goulburn, Murray and Broken systems when allocations on these systems reached 20%. The qualification on the Loddon, Bullarook, and Campaspe systems will remain in place until allocations on these systems reach 50%.
The Minister for Water has also temporarily qualified rights to water in the Campaspe Water Supply Protection Area to enable an increased groundwater seasonal allocation for 2007/08.
Coliban Rural System
Coliban Water increased its rural season allocation to 35% on 14 December due to October and November inflows and operational savings. The rural season opened in September with a 30% allocation. The opening allocation was the minimum needed to run the rural system with some efficiency.
Coliban Water also announced an offer of supplementary recycled water for some rural customers. A total of 400 ML of recycled water will be made available to the rural customers connected into the Bendigo recycled water system. This water is separate to the rural allocation and is available to customers on the Axe Creek and Ascot channel systems who lodge an expression of interest with Coliban Water by January 18, 2008.
Wimmera Mallee Domestic and Stock Supply System
Supplies to all customer groups are being made available in accordance with the restriction schedule contained in the Wimmera-Glenelg bulk entitlements. Restrictions are as follows:
- towns are on Stage 4 restrictions;
- domestic and stock supply to farms is limited to one dam per enterprise in most areas, with limited pipeline supply in areas where pipeline completed, and carting of water around Berriwillock and Culgoa;
- irrigation supplies are zero;
- no supply is available for irrigation diversions on Wimmera River;
- supply to recreation lakes has been nil since 2000.
Although the Wimmera and Mallee districts have received average rainfall in the past 3 months, levels in Grampians Headworks storages continued to decline in December. This was largely due to the release of water for the channel run.
At 31 December 2007, storages in the Wimmera Mallee domestic and stock supply system had reduced to approximately 5.0% of capacity.
GWM Water began the winter channel run in September with the aim of filling occupied house dams on all winter channels that will not be piped in the next 12 months. The channel run is now expected to be completed by mid to late January because of the recent hot weather. However, early December rainfall has removed the need to pump dead storage from Taylors Lake to supplement the run.
GWM Water expects that about 2,500 dams, or 18% of the total number of dams in the channel system, will be filled. Customers on the Wimmera Mallee pipeline systems 1 and 5 will not be supplied a dam fill; however carting in those areas will continue until they get a pipeline supply later this year.
A total of 10.6 ML (423 loads) of domestic water was delivered to rural properties during December. This compares to approximately 8.3 ML in November. There is enough water available in storage to meet any water carting demands for the next 12 months as towns storages have now been filled, or are receiving supplies from the Wimmera-Mallee Pipeline.
GWM Water continues to review arrangements for the summer channel run, which supplies Clear Lake, Natimuk and Noradjuha and farm dams in the area. A decision to proceed with the summer channel run will be made by 1 February 2007. Current forecasts continue to indicate that there will not be enough water available for the run to occur this summer. However, Natimuk and Noradjuha received enough local runoff in April and May this year to meet demands until mid 2008 on stage 4 restrictions. Clear Lake is receiving water via carting at present, which is considered to be a satisfactory arrangement for the coming year.
The Minister for Water qualified the Wimmera-Glenelg bulk entitlements to enable environmental water to be retained for emergency consumptive use over the coming year or until the system's storage recovers.
Southern Rural Water
Macalister Irrigation District (MID)
At 31 December, Lake Glenmaggie, the principal source of water for the MID, was at 98.6% of capacity.
Continuing inflows allowed SRW to increase the allocation from 100% to 105% on 27 December for all irrigators within the MID, and for diverters on the Thomson River, Macalister River and Rainbow Creek. This allocation is in addition to the 46,000 ML, equivalent to 32% of water right volume, delivered during the off-quota period up to 20 November.
The outlook for the Macalister Irrigation District remains positive, however any further increase in allocation will depend on further inflows over summer and autumn.
Latrobe System
Water availability on the Latrobe system increased throughout December with Blue Rock Lake increasing 0.9% to 80.9% of capacity. However, at 31 December the irrigation share stood at just 1,433 ML. This equates to just 34.4% of regulated allocation.
In December, Southern Rural Water (SRW) license holders downstream on the Latrobe and Tanjil Rivers could pump up to their licensed volume, however availability was limited by unregulated river flows (which normally contribute some 70% of entitlements). SRW will announce a formal initial allocation (share of water in Blue Rock reservoir) for the 2007/08 season when unregulated flows in the Latrobe reduce to the minimum environmental flows.
Werribee Basin (Bacchus Marsh and Werribee Irrigation District)
SRW’s share of the Werribee Basin storages rose to 12.4% of capacity during December (an increase of 0.7% since 30 November) but remains very low for this time of year.
SRW has again implemented its Western Irrigation Contingency Plan which includes:
- Pumping of dead storage from Pykes Creek reservoir;
- Transferring 2,000 ML of water from the SRW Drought Reserve in the Thomson Reservoir to Werribee and Bacchus Marsh; and
- Extending Government approval to make 800 ML of water available to irrigators from the unallocated share of Lake Merrimu.
Modest inflows in December enabled SRW to increase the allocation for the system to 8% water right.
Irrigators in the Werribee area continue to participate in the recycling scheme. This is proving to be of major benefit to participating growers in the area (now approaching 90% of the growers). However, algal blooms at the Western Treatment Plant interrupted supplies for several weeks, forcing irrigators to draw heavily on their limited river water allocations. Uninterrupted supplies will resume in early December.
The ban on access to groundwater within the Deutgam Groundwater Management Area remains in place. SRW continues to monitor levels in the aquifer. Access to the resource will resume when the risk of salt water intrusion has diminished.
Maribyrnong Basin
The storage volume in Rosslynne Reservoir remains low at 4.8% of capacity. With inflows well below average, SRW diverters face another season of low, possibly zero, allocations.
The allocation remains at 0% of licensed volume.