Sydney
Water accounting policies

a. Introduction

The information presented in the Sydney region is based on agreements between the Bureau of Meteorology (the Bureau) and reporting partners, including:

  • New South Wales Office of Water
  • Sydney Catchment Authority
  • Sydney Water Corporation
  • Shoalhaven City Council
  • Wingecarribee Shire Council
  • Goulburn Mulwaree Council
  • Lithgow City Council.

The 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 litres presented as megalitres (ML).

b. Recognition of water assets and water liabilities

Only water that is held or managed by the State 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 provided:

  • the 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 provided:

  • the 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.

c. Recognition of changes to 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 presented in the Statement of Changes in Water Assets and Water Liabilities or the Statement of Water Flows.

Precipitation and evaporation are recognised only in relation to the surfaces of open storage volumes and unregulated river channels (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).

The portion of runoff that flows into the surface water store (storages and rivers) is quantified and recognised on the Statement of Changes in Water Assets and Water Liabilities or the Statement of Water Flows. This runoff includes precipitation captured in the catchment less evaporation and infiltration and is recorded as line item 9.4 Runoff to surface water.

Allocation announcements on regulated entitlements have been recognised as an increase in water liabilities. Note that the definition of regulated or unregulated entitlements for the purpose of the National Water Account (refer to Glossary) may be different to the meaning applied by the jurisdiction. Please refer to the Water access and use note for more information on the allocations.

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

The volumes of several water assets identified in the Sydney region were not reported in the water accounting statements but replaced by dashes ('–') as they failed the recognition criteria specified in the Australian Water Accounting Standard 1 (the Standard).

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 fail the recognition criteria

The volumes of several changes to water assets identified in the Sydney region were not reported in the water accounting statements but replaced by dashes ('–') as they 'failed the recognition criteria' specified in the Standard, because:

  • they could not be quantified in a way that is complete, neutral, and free from material error; and/or
  • they were unlikely to provide a future benefit to the region or the region's stakeholders.

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

f. Restatement of comparative information

In accordance with the Standard, comparative year volumes must be restated in the water accounting statements if there is a prior period error, or a change in line item presentation. Comparative year volumes are not required to be restated if there is a change in methodology or subsequent data availability for the quantification of a line item.

The following line items have required restatment in the 2013 Account.  

See the individual line item note for an explanation of the changes.

The following comparative year information also applies to the 2013 Account.

Changes to the representation of groundwater
In the 2012 Account, estimated groundwater extractions associated with the reported groundwater rights were provided in 18.7 Groundwater extractions – other statutory rights. Information on groundwater assets were not provided due to difficulties in quantification in the 2012 Account. Given the lack of available data, quantifying the groundwater asset is difficult. Reporting on estimated groundwater extractions against an unquantifiable asset provided little benefit to the region and the resulting unaccounted-for difference for groundwater could be misleading and open to misinterpretation.

After discussions with the Sydney region reporting partners, the decision was made to remove these groundwater extractions from the water accounting statements and only report on groundwater rights under 'Groundwater rights' in the Water access and use section. Therefore, the 2012 Account comparative year information in relation to groundwater rights and extractions have been removed and only naturally occurring groundwater flows are included and defined by a '–'.