5.1 Surface water allocation remaining

Supporting Information

The volume presented in the water accounting statements (13,946 ML) represents the allocation remaining for high-reliability water shares and low-reliability water shares in the Melbourne region. According to Southern Rural Water's Werribee & Bacchus Marsh Allocation Method, any unused allocation at the end of the season (30 June) will be part of the opening allocation at the start of the following season (1 July).

A large portion of allocations made during the 2010–11 year were left unused at the end of the period due to the wet year in the region, and relatively low diversions.

The surface water allocation remaining was calculated as shown in the following table:

Surface water allocation remaining

Account Volume (ML)

Opening balance (30 June 2010) 937

21.1 Surface water allocation announcements


17.11 Surface water allocation diversion


13.1 Adjustment and forfeiture of surface water allocation


Closing balance (30 June 2011) 13,946

Quantification Approach

Data Source

Werribee System Allocation Model.

Provided by

Southern Rural Water.


Surface water allocation remaining was calculated according to the Werribee & Bacchus Marsh Allocation Method.

Details of the allocation model are available on the Southern Rural Water website.

Assumptions, Limitations, Caveats and Approximations


Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This item corresponds to line item Allocation on regulated flows remaining – high security, individual irrigator reported in the 2010 Account.The comparative year volume is 937 ML.