Melbourne
21.1 Surface water allocation announcements

Supporting Information

The volume recognised in the water accounting statements (19,521 ML) represents the volume of water announced for high-reliability water shares and low-reliability water shares in the Melbourne region during the 2010–11 year. Allocations are made according to Southern Rural Water's Werribee & Bacchus Marsh Allocation Method.

Allocations were relatively high in the Melbourne region during the 2010–11 year due to the wet conditions across the region. The following table shows the breakdown of allocations made in the Melbourne region during the 2010–11 year.

Allocation announcements for high-reliability and low-reliability water shares in the Melbourne region during the 2010–11 year
Class Location

Entitlement volume (ML)

Allocation
(% of entitlement)

Allocation
volume (ML)

High-reliability water shares Werribee Irrigation District 10,040 100 10,040
Werribee River 907 100 907
Bacchus Marsh Irrigation District 3,880 100 3,880
Lake Merrimu direct access 190 100 190
Bacchus Marsh other 521 100 521
High-reliability water shares total 15,538 100 15,538
Low-reliability water shares Werribee Irrigation District 4,777 55 2,627
Werribee River 435 55 239
Bacchus Marsh Irrigation District 2,030 55 1,117
Low reliability water shares total 7,242 55 3,983
Total all water shares 22,780 86 19,521


The following table shows the breakdown of allocation announcements by month. High reliability water shares started at 8% in July 2010, and increased to 30% in August following a wet period. Wet conditions prevailed through September and October, and allocations for high reliability water shares increased to 63% and 70% respectively. Significant rainfall late in November resulted in allocations reaching 100%. This was the highest allocation since 2001–02.  At the same time during the 2009–10 year, allocations were 6% of high reliability water shares.

Low reliability water shares did not receive an allocation announcement until high reliability shares reached 100% in November 2010 (as per the Werribee & Bacchus Marsh Allocation Method). The initial announcement of 10% in November was followed by an increase to 25% in December, and another increase to 45% in January 2011. A further five percent increase in February and another five percent increase in April saw the total allocation rise to 55% for the year.

Breakdown of allocation announcements by month
Irrigation area Water share 2010 2011
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Werribee and Bacchus Marsh High reliability(%) 8 30 63 70 100 100 100 100 100 100 100 100
Low reliability(%) 0 0 0 0 10 25 45 50 50 55 55 55

Comparative year

 The comparative year volume is 3,490 ML.