Adelaide
Water accounting policies

a. Introduction

The information presented in the Adelaide region report is based on agreements between, and information provided by:

  • South Australian Department for Environment, Water and Natural Resources (DEWNR)
  • South Australian Water Corporation (SA Water)
  • Bureau of Meteorology (the Bureau).

The report has been prepared using an accrual basis of water accounting, with the exception of the 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 licensing authority, the region's irrigation scheme, or the region's urban water system, and from which future benefit can be derived by stakeholders is defined as a water asset. Water liabilities consist of 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.

Water held in off-channel water stores (farm dams) is not identified as a water asset as the National Water Account considers that it has already been abstracted from the pool of water available for public sharing that is managed by the state licensing authority; however, information about off-channel water stores is provided in the off-channel storages section of the 'Water resources and systems' note because it is considered useful to users of the National Water Account and the water they intercept reduces inflows into the water assets of the region.

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 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 (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 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 9.4 Runoff to surface water.

Allocation announcements on entitlements that create a water liability have been recognised as an increase in water liabilities. Note that the definition of entitlements that create a water liability for the purpose of the National Water Account (refer to 'Glossary') may be different to the meaning applied by the jurisdiction. For more information on allocations, refer to the Water rights, entitlements, allocations and restrictions note.

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

The volumes of several water assets identified in the Adelaide region were not recognised 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
  • they were unlikely to provide a future benefit to the region or to the region's stakeholders.

The description of those water assets 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 Adelaide 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
  • they were unlikely to provide a future benefit to the region or the region's stakeholders

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

In accordance with the Australian Water Accounting Standard 1, comparative year volumes must be restated in the water accounting statements if there is a prior period error identified in the previous year's account or there is a change in presentation or classification of a report line item. 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 a line item.

The comparative year volume for line item 17.2 River outflow from region was restated in the water accounting statements from the 2012 Account due to a change in presentation. This change in presentation included:

  • the removal of three streamflow gauging sites (A5011007, A5011010 and A5011011) from the quantification of this line item as the period of record for these three sites ended in August 2010 and it was not suitable to interpolate data for these sites. There were no suitable replacement sites.
  • the replacement of streamflow gauging site A5041052 for A5041005 in the quantification of this line item as the period of record for A5041005 ended in February 2012.

The comparative year volumes for the following line items were restated in the water accounting statements from the 2012 Account due to an error identified in the method used:

The prior period error was a result of using solar radiation data with bias correction errors, which is an input for the below listed line item volume calculations.  The line item volumes for the 2011-12 year were recalculated accommodating the prior period error correction, as shown in the following table.


Comparison of 2011–12 volumes published in the 2012 Account and restated volumes in the 2013 Account
Line item Correct 2011–12 volume reported in 2013 Account (ML) Incorrect 2011–12 volume reported in 2012 Account (ML) Difference (ML)
9.4 Runoff to surface water 280,833 287,548 (6,715)
10.3 Recharge from landscape 303,370 299,451 3,919
10.5 Leakage from off-channel water storage 1,038 930 108
17.1 Evaporation from surface water 15,943 17,433 (1,490)
17.2 River outflow from region 137,375 167,672 (30,297)
18.3 Discharge to landscape 102,443 155,177 (52,734)

As a result of restating the line items in the previous table, the volume reported at line item 25.1 Unaccounted-for difference was also restated for the 2011–12 year. The unaccounted-for difference was restated from 194,215 ML reported in the 2012 Account to 276,048 ML, representing an increase of 81,833 ML in the unaccounted-for difference reported.

g. Transactions within the region

In the National Water Account, 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
  • users found the presentation of these internal transactions in the water accounting statements 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.

Transactions that were excluded from the consolidated water accounting statements are reported in store specific water accounting statements in the Water resources and systems note. This ensures that between store flows and between store liabilities/claims are still reported.