The Melbourne region’s Statement of Changes in Water Assets and Water Liabilities and Statement of Physical Water Flows show an unaccounted volume of 79,796 ML for the water distribution system store for 2009–10 (12% of the total water assets). This volume is the amount required to reconcile the outflow volumes against the volume in the water distribution system store.
The main reason for this unaccounted volume is an underestimation of outflows. Techniques for estimating outdoor use – for example, of water supplied by the water distribution store – were not sufficiently accurate to allow a volume to be faithfully quantified.
The unaccounted-for difference is calculated according to the table below.
| Account | Volume (ML) | |
|---|---|---|
| Opening balance (01 July 2009) water distribution store |
24,947 |
|
| add | Total 19 Water distribution store inflows |
361,401 |
| minus | Total 20 Water distribution outflows |
281,108 |
| minus | Closing balance (30 June 2010) water distribution system store |
25,444 |
| Unaccounted-for difference |
79,796 |