Canberra
Water accounting policies

a. Introduction

The information presented in the Canberra region water accounting report is based on agreements between ActewAGL, Actew Corporation, Queenbyean City Council and information provided by the Australian Capital Territory Government, Environment and Sustainable  Development Directorate and the New South Wales Office of Water.

This report has been prepared using an accrual basis of water accounting, with the exception of the physical water flow information. The water attribute being quantified is volume and the unit of account is megalitres (ML).

b. Recognition of water assets and water liabilities

Only water that is held or managed by the state or territory licensing authority, or the region's urban water system, and from which future benefit can be derived by stakeholders of the region, is defined as a water asset. Water liabilities are constituted by present commitments to supply water, the discharge of which is expected to result in a decrease of the region's water assets or an increase in another water commitment to supply water.

A water asset is recognised in the Statement of water assets and water liabilities providing:

  • its volume can be quantified in a way that is complete, neutral and free from material error
  • the derived benefit is probable.

A water liability is recognised in the Statement of water assets and water liabilities providing:

  • its volume can be quantified in a way that is complete, neutral and free from material error
  • the decrease of the region's water assets or increase in another water commitment to supply water is probable.

Water held in off-channel water storages that has already been abstracted from the entitlement system is deemed not to be part of the region (regardless of the storage's size or connection to the system). This is because the attendant water right has already been exercised. 

c. Recognition of changes in water assets and water liabilities

The increases and decreases to the reported water assets and water liabilities consist of changes that can be quantified in a way that is complete, neutral and free from material error. These volumes are reported in the Statement of changes in water assets and water liabilities or the Statement of physical water flows.

Precipitation and evaporation are recognised only in relation to the surfaces of open storage volumes (9.1 Precipitation on surface water and 17.1 Evaporation from surface water). They do not represent all precipitation, evaporation and evapotranspiration within the region (notably, these processes occurring from the landscape are not captured).

That portion of runoff that flows into the surface water store (storages and rivers) is quantified and recognised in the water accounting statements This runoff includes precipitation captured in the catchment less evaporation and infiltration and is recorded as 9.4 Runoff to surface water.

d. Water assets and water liabilities that fail the recognition criteria

The volumes of several water assets and water liabilities identified in the Canberra region were recognised in the water accounting statements but replaced by dashes ('–') because they 'failed the recognition criteria' specified in the Exposure Draft of Australian Water Accounting Standards 1 (the Standards), as:

  • they could not be quantified in a way that is complete, neutral and free from material error
  • in the case of water assets, they were unlikely to provide a future benefit to the region or the region's stakeholders
  • in the case of water liabilities, they were unlikely to result in a decrease in the region's water assets or an increase in another water liability when the obligation is discharged.

The description of those water assets and water liabilities that failed the recognition criteria is given in the following line item notes:

e. Changes to water assets and water liabilities that were not recognised

The volumes of several changes to water assets and water liabilities identified in the Canberra region were not recognised in the water accounting statements but replaced by dashes ('–') because they could not be quantified in a way that is complete, neutral and free from material error.

The description of those changes to water assets and water liabilities that failed the recognition criteria is given in the following line item notes:

f. Restatement of comparative year information

Several comparative year volumes in the water accounting statements were restated from the 2010 Account in order to provide more useful information to the users. Restatements may be due to:

  • error committed in the 2010 Account, referred to as prior period error
  • change in the presentation of the water accounting statements, where line items were generally simplified since the 2010 Account
  • change in scope; for instance to include more of the region's area in the definition of a line item in order to present more complete information
  • improvement in quantification methodology
  • increase in the data available to quantify a line item.

In accordance with the Exposure Draft Australian Water Accounting Standards 1, prior error corrections, changes of presentation and scope of the line items led to an automatic restatement of the values in the water accounting statements. Changes of methodologies and data availability, although not required by the Standards, led to restatement of the volumes in the water accounting statements only if the change was considered material by the report preparers. In particular, any change affecting the allocation accounts was restated.

Change in presentation of the water accounting statements

In the 2010 Account, internal transactions between various water assets and water liabilities of the region were reported in the water accounting statements. In the 2011 Account, these internal transactions are not reported in the water accounting statements for the following reasons:

  • they did not affect the region's total water assets and water liabilities
  • feedback was received that presenting these internal transactions in the water accounting statements was confusing, as the same water appeared in the water accounting statements as both a claim to water and an obligation to deliver water, and as both inflows and outflows in relation to the various water assets and water liabilities.

In the 2011 Account, these internal transactions are reported instead in the Resources and systems suite of notes: Surface water, Groundwater, Urban system and Irrigation schemes.