Irrigation Allocations - May 2007
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Goulburn-Murray Water (G-MW)
Goulburn-Murray Water (G-MW) announced the final water allocation for the season on 16 April 2007. The season for all gravity irrigation system customers closed on 30 April 2007. Private diversion customers are not affected by the close of the gravity irrigation system, and will be able to use their allocation until 30 June 2007.
G-MW released its latest outlook for the 2007/08 irrigation season on 15 May 2007.
Outlook for Start of Season
A repeat of record dry conditions experienced in 2006/07 will not provide any water for irrigation in any system on 2 July 2007. Under dry conditions (where inflows are at a level that are exceeded 9 times in 10) the 15 August allocation would remain at zero for all systems.
Outlook for Spring 2007
Dry conditions would not give enough water for an allocation in any system by 15 October 2007. Under average conditions (5 chances in 10), the following allocations will be made available:
- Murray system: 32%
- Goulburn system: 73%
- Campaspe system: 100%
Wet conditions (1 chance in 10) could provide for an allocation of 100% for all systems.
Outlook for February 2008
Average conditions (5 chances in 10) will enable an allocation of 100% water shares for all systems. Very wet conditions would provide for:
- 100% of high-security shares in the Murray system;
- 100% of water shares in the Goulburn system (but no allocation of low-reliability water shares); and
- Maximum allocation of high-reliability and low-reliability shares in the Campaspe system.
Dry conditions would enable an allocation of 29% in the Murray system, 25% in the Goulburn system and just 4% in the Campaspe system.
G-MW will announce the opening season allocation on 2 July 2007.
Coliban Rural System
The irrigation season closed on 15 May. A zero allocation was in place for Coliban rural licence holders for the 2006/07 season. A temporary qualification of rights has been made to allow the supply of a limited amount (30% allocation) of water to sustain permanent plantings, food production and intensive animal industries. Other licence holders are eligible for a water cartage rebate from Coliban Water, for water carted for essential in-house use (up to 30,000 litres).
Wimmera Mallee Domestic and Stock Supply System
The Grampians area received significant rainfall in May (Ararat 102mm, Stawell 96mm, Mount William 240mm, Horsham 65mm) which has resulted in good inflows to all of their storages.
At 31 May 2007, storages in the Wimmera Mallee domestic and stock supply system were at 4.6% of capacity (compared with 6.5% at the same time last year).
Grampians Wimmera Mallee Water (GWMW) requires a total of about 35GL to provide unrestricted demands and 25GL to provide Stage 4 restricted demands. They currently have 34.5GL in storage, however approximately 1/6th of this is of poor quality or inaccessible.
A water cartage program is being implemented, full details of which are available on GWMW’s website. GWMW is delivering 28,000L of water for domestic use every second month to rural customers not receiving a house dam fill when existing house dam supplies become unusable. The purchase of a water tank is eligible for up to a $3,000 rebate from the Victorian Government. The demand for rural carting has decreased over recent months.
Additional water is also available to GWMW rural customers, including those who receive a house dam fill, for stock watering and crop spraying. Water is provided at no cost, but carting arrangements and costs are the customer’s responsibility.
Water is also available at a cost of $1.20/kL under a permit system for carting by others (at their own cost) who are not customers of GWMW. This water is for domestic use only.
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;
- irrigation supplies are again zero;
- no supply is available for irrigation diversions on Wimmera River;
- supply to recreation lakes has been nil since 2000;
- commercial supplies to major customers are zero.
Southern Rural Water
Macalister Irrigation District (MID)
The irrigation season ended on the 15 May with the final allocation for all MID diverters being at 60% of Licensed Volume, Water Right and Domestic and Stock.
The storage position of Glenmaggie Reservoir, the principal source of water for Thomson-Macalister Irrigation District (MID), improved throughout May and was holding 13% of capacity at the end of the month.
Latrobe System
Water availability on the Latrobe system remains reasonable, with Blue Rock Lake being at 49.8% of capacity. Southern Rural Water (SRW) license holders downstream on the Latrobe and Tanjil Rivers are permitted to take up to their licensed volume, however availability is limited by low unregulated river flows (which normally contribute some 70% of entitlements). To this point, Latrobe/Tanjil irrigators have received less than 25% of their licence volume.
Werribee Basin (Bacchus Marsh and Werribee Irrigation District)
Werribee Basin storage volumes remained steady at 8.0% throughout May. SRW’s share was at 4.0%.
Because of the low storage situation, initial allocations for the 2006/2007 season were 0% for the Bacchus Marsh irrigation area and 5% for the Werribee irrigation area. These were increased to 10% on 23 October 2006 after SRW began to pump dead storage from Pykes Ck Reservoir. Full domestic and stock entitlements are now also available in both areas. Further increases remain unlikely.
A range of other measures are in place to assist in ameliorating the supply situation:
- Irrigators in the Werribee area participating in the recycling scheme (now approaching 85% of growers) are able to access recycled water. Some 7,200ML of recycled water have been delivered to growers this season.
- SRW installed a connection to enable spare capacity in Western Water’s Merrimu Reservoir to Bacchus Marsh pipeline to be used to bring water from SRW’s entitlement in Merrimu into the Bacchus Marsh Irrigation District.
- A ministerial approved revision of the depth boundary for the Merrimu GMA has allowed for additional access to groundwater for Bacchus Marsh growers.
- The Minister allocated 1200ML of unallocated water in Merrimu Reservoir for use to maintain business viability in Bacchus Marsh. Of this, approximately 200ML has been delivered so far to growers and industry in the region.
Levels in the Deutgam Groundwater Management Area declined through 2005/06. In order to protect the resource from seawater intrusion, allocations for the 2006/07 season were set at 25% of licensed volume. Southern Rural Water expect to introduce a groundwater ban before July as levels continue to decline in 2006/07.
With inflows well below average, storage volumes in Rosslynne Reservoir continued to decrease and are now at 4.0% of capacity (compared to 7.3% at the same time last year). Current allocations for SRW diverters remain low at 5%.