National Water Account 2017

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Key findings

Climate and water

Water Accounting Statements

Supporting information

Region description

Reference information

Murray–Darling Basin: Governance

Accountability Statement

1. This water accounting report has been prepared and presented in accordance with the Australian Water Accounting Standards, with the following exceptions:

• No assurance statement was prepared because the standard for, and practice of, assurance of water accounting reports are currently not available.
• Notes on the quantification approaches and levels of uncertainty are incomplete because the knowledge base is often inadequate.
• No information is disclosed about material events that occurred after 30 June 2017, such as extreme precipitation and significant water rights purchases. This information is publicly available elsewhere.
• The volumes of changes to water assets and water liabilities that failed the recognition criteria were reported in the water accounting statements with dashes ('–') in order to highlight data and knowledge gaps that may affect the water accounting statement balances.

2. The report has been compiled from the best data available, as detailed in the water accounting statement notes, in the time available to compile it from a number of sources. The Bureau of Meteorology takes a nationally-consistent approach to report preparation and presentation. Therefore, for a few items there may be local data of higher quality that were not used.

3. All significant and specific interpretations of the Australian Water Accounting Standard 1 for the purpose of the preparation of this report are explained in the 'Water accounting policies' note. The Bureau of Meteorology is responsible for these interpretations.

Robert Argent

General Manager Water

Bureau of Meteorology

7 June 2018

Water accounting policies

Introduction

The information presented in the Murray–Darling Basin region water accounting report is based on agreements between the Bureau of Meteorology (the Bureau) and:

• the Murray–Darling Basin Authority (MDBA)
• Snowy Hydro Limited.

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) in quantifying and either ML or gigalitres (GL) in presenting. Where a reported volume is negative, it is shown in brackets. The applicable reporting period is from 1 July 2016 to 30 June 2017. The surface water diversion volumes reported in 'Key findings' and 'Water access and use' are net volumes. The reported surface water diversion volumes also exclude interceptions (plantations and run-off dams). Volumes reported in all other sections of this report were the gross volumes for 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.

Recognition of water assets and water liabilities

Recognition of changes in water assets and water liabilities

The increases and decreases to the water assets and water liabilities reported consist only 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 on storage surfaces and only for major rivers within the region. These include storages, lakes, weirs, and locks in the regulated and unregulated rivers. It does not represent all precipitation, evaporation and evapotranspiration within the region (notably, these processes occurring from the landscape are not captured).

The portion of runoff from landscape that flows into the surface water store is quantified and recognised in the Statement of Changes in Water Assets and Water Liabilities and the Statement of Water Flows. This runoff includes precipitation captured in the catchment less estimated evaporation and seepage and is recorded as runoff to surface water.

Allocations announced 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 for more information on the allocations.

The volume of water that returns after urban use, recorded as discharge from urban supply system and discharge from wastewater system, meets the identification criteria as an increase to water assets; wherever it could be quantified accurately, it is recognised in the Statement of Changes in Water Assets and Water Liabilities and Statement of Water Flow.

Other groundwater increases and other groundwater decreases do not represent any physical groundwater flow. The volumes provided represent the change of the long-term estimates of volumes for extraction between the reporting year and the previous year. These changes were as a result of revision of SDL volumes, implementation of new water sharing plans, abolition of existing plans, or changes made to New South Wales supplementary access licences. Both the Statement of Changes in Water Assets and Water Liabilities and Statement of Water Flows include 'Other groundwater increases' and 'Other groundwater decreases'.

Changes to water assets and water liabilities that fail the recognition criteria

There are no items to report under this category for the 2017 Account.

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 was 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 2016 Account due to several reasons.

Restatements due to prior-period errors have been made to correct data translation and calculation errors.

The volume for river and floodplain losses for the 2015–16 year has been restated as a result of an update to the surface water store variables, which are inputs to the water balance calculation for this item.

Reporting of water trade

Reporting of external transfers

Transfers of water that occur across the boundaries of the Murray–Darling Basin region and impact on the water assets and water liabilities of the region are reported in the water accounting statements. Information about these transfers is also provided in the 'Water resources' section of the 'Geographic information' (Figure R8) note.

Level of reporting in case of bulk entitlements in Victoria

When water is managed under a bulk entitlement in Victoria (see Water entitlements and other statutory water rights section under 'Water rights'), the 2017 Account reports at the level of the collective retail water access entitlements issued under the bulk entitlements. This means that the water liabilities identified against the region are the allocations announced on these retail entitlements and for bulk entitlements held for the benefit of the environment. Where a bulk entitlement holder has a claim over water located outside the region, that claim will likewise be identified as a water asset of the region.

Net change in water storage to the change in net water assets