Melbourne
19.11 Transfer of water outside of region

Supporting Information

The volume presented in the water accounting statements (53 ML) represents the volume of water transferred outside of the region from Mount Macedon to Woodend via Western Water's water supply infrastructure.

The transfer is part of the regular operations of Western Water in providing water to customers within their service area. The service area of Western Water overlaps with the boundary of the Melbourne region.

Quantification Approach

Data Source

Western Water Information Technology database.

Provided by

Western Water.

Method

The volume of water diverted from Mount Macedon to Woodend is metered and read weekly.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This item corresponds to line item 20.6 Water transferred-out reported in the 2010 Account. In the 2010 Account, this line item was unquantified. However, the volume of urban water transferred out of the region was incorrectly reported at line item 14.9 Diversion of surface water for transfer-out under inter-basin agreement.

In the 2010 Account, the volume reported at line item 14.9 Diversion of surface water for transfer-out under inter-basin agreement included:

  • potable water supply from Western Water to Woodend
  •  non-potable water supply from Western Water to Woodend from Macedon storage
  • non-potable water exported from Melbourne Water via the Tarago catchment to Gippsland Water.

An improved understanding of the nature of the inter-region surface water commitment identified non-potable and potable water supplied from Western Water is not transferred under an inter-region commitment rather, this transfer is part of the regular operations of Western Water in providing water to customers within their service area. Thus, these volumes should be reported as a transfer out of the region from the urban water system.

Restatement of the value published in the 2010 Account was made as the change was material and increased the accuracy and comparability of the information provided to the users of the National Water Account. The changes and their respective values are detailed in the following table. The restated comparative year volume is 135 ML.

Restated comparative year information for line item 19.11 Transfer of water outside of region

2010 Account line item name

Water exported

Volume at 30 June 2010 reported in the 2010 Account (ML)

Value difference to volume reported due to prior period error correction (ML)

Volume at 30 June 2010 reported in 2011 Account (ML)

14.9 Diversion of surface water for transfer-out under inter-basin agreement

Non-potable water exported from Melbourne Water via the Tarago catchment to Gippsland Water

546

-546 

 

Potable water supply from Western Water to Woodend

58

 

58 

Non-potable water supply from Western Water to Woodend from Macedon storage

77

 

77 

Total

 

681

-546

135