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National Water Account 2015

Sydney: Water accounting policies

Warragamba Dam, New South Wales (iStock © Kokkai Ng)

Introduction

The information presented in the Sydney region is based on collaboration between the Bureau of Meteorology (the Bureau) and:

  • New South Wales Department of Primary Industries – Water (DPI Water)
  • WaterNSW
  • 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). Where a reported volume is negative, it is shown in brackets. The applicable reporting period is from 1 July 2014 to 30 June 2015.

 

Recognition of water assets and water liabilities

Only water that is held or managed by the State licensing authority or the urban utilities and from which a future probable 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 probable decrease of the region's water assets or a probable increase in another water commitment to supply water.

Provided its volume can be quantified in a way that is complete, neutral, and free from material error, the volume of the water asset or water liability is recognised in the Statement of Water Assets and Water Liabilities.

Water held in 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.

 

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 Water Flows.

Precipitation and evaporation are recognised only in relation to the surfaces of open storage volumes. 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 Statement of Changes in Water Assets and Water Liabilities. This runoff includes precipitation captured in the catchment less evaporation and infiltration, and is recorded as Runoff to surface water.

Allocation announcements on regulated entitlements have been recognised as increases 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 rights, entitlements, allocations and restrictions note for more information on the allocations.

 

Water assets and water liabilities that fail the recognition criteria

The volumes of several water assets and water liabilities 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, 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.

Water assets that failed the recognition criteria include a part of unregulated rivers, regulated rivers, lakes and wetlands (see Surface water note), groundwater store (see Groundwater note) and a part of urban water store (see Urban water system note).

 

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 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, 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.

 

Restatement of comparative year information

In accordance with the Australian Water Accounting Standard 1, comparative year volumes must be restated in the statements if there is a prior period error or a change in item presentation. Comparative year volumes are not required to be restated if there is a change in scope or methodology or subsequent data availability for the quantification of an item.

The following comparative year volumes in the water accounting statements were restated from the 2014 Account due to a change in presentation:

  • Supply system delivery: urban users
  • Recycled water delivery: urban users
  • Other supply system decreases
  • Other wastewater and recycled water system decreases
  • Supply system delivery: inter-region
  • Recycled water delivery: inter-region.

This change in presentation separated water flows to and from the urban water supply system from flows to and from the wastewater and recycled water systems, providing clearer information to users of the National Water Account. The above changes are summarised in Table N1.

 

Table N1 Changes in item volumes presentation from the 2014 Account
Item descriptionRevised 2014 volume in 2015 Account
(ML)
Reported volume in 2014 Account
(ML)
Supply system delivery: urban users487,104509,122
Recycled water delivery: urban users22,0180
Other supply system decreases15,15318,909
Other wastewater and recycled water system decreases3,7560
Supply system delivery: inter-region01,580
Recycled water delivery: inter-region1,5800

 

Transactions within the region

Transactions between water assets and water liabilities within the region (e.g. between the surface water store and the groundwater store) are not reported in the water accounting statements because they do not affect the region's total water assets and water liabilities.

This information is reported in the Water resources and systems note, which contains water accounting statements for each water store within the region. These contain internal transactions that were excluded from the consolidated water accounting statements. This ensures that transactions between water assets and water liabilities within the region are still reported.