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Governance

The following section describes the governance in place within the National Water Account and is applicable for all accounting regions.

 

Accountability statement

Lake Burley Griffin, Canberra region (Bureau of Meteorology © Malcolm Watson)

 

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

  • No Assurance Statement was prepared because the practice of assurance of water accounting reports are currently not available.
  • No information is disclosed about material events that occurred after 30 June 2020, such as extreme precipitation and significant water rights purchases. This information is publicly available elsewhere.
  • The volumes of water assets and water liabilities, including 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.

 

Jeff Perkins

General Manager, Environmental Prediction Services

Bureau of Meteorology

25 February 2021

 

Water accounting policies

Barwon River, Murray–Darling Basin region (Bureau of Meteorology © Malcolm Watson)

 

Introduction

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).

 

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 utilities is recognised as a water asset, provided that a future benefit can be derived from that water and that the volume can be quantified.

 

Recognition of changes in water assets and water liabilities

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.

The volume of runoff that flows into the surface water stores includes precipitation that lands on the landscape, less evaporation and infiltration.

 

Restatement of comparative year information

Between-store flows

In the 2015–2017 Accounts, transactions between water assets and water liabilities within the region (e.g. between the surface water store and the groundwater store) were not reported in the water accounting statements. In this account, however, these between-store transactions were included as they provide a better understanding of the water movement that occurs at each water store or system. Comparative year volumes for these transactions are also reported.

 

Adelaide

Urban water system

Comparative year volumes for several urban flow volumes were restated from the 2015 Account due to a change in presentation associated with amendments to the Water Regulations in 2016. A primary aim of these amendments was to reduce reporting burden on urban utilities and town councils. This change in presentation included the removal of inter-region water transfers and deliveries associated with areas outside of SA Water's operational boundary. In addition, evaporation from the urban system was reclassified as a loss from the wastewater and recycled water system. The comparative year items restated in this account include:

  • Wastewater collected
  • Supply system transfer: inter-region
  • Recycled water delivery: urban users
  • Other wastewater decreases
  • unaccounted-for difference.

 

Canberra

Surface water store

Comparative year volumes related to the surface water store were restated from the 2015–2017 Accounts due to a change in presentation. In 2018, the Bureau of Meteorology and the Australian Bureau of Statistics produced a pilot Integrated Water Account for the Canberra region for a 4-year period between 2013–2017. The account used the latest methodology to establish most of the inflows and surface water storage volumes. To align the National Water Account for the Canberra region with the Integrated Water Account, the following comparative year items were restated:

  • Storages
  • Rivers
  • Lakes and wetlands
  • Precipitation
  • Inter-region inflow
  • Runoff
  • Flood return
  • Wastewater discharge: surface water
  • Evaporation
  • Outflows
  • Overbank flow.

The urban system storage item was also restated to align with the Integrated Water Account.

 

Water abstractions

Comparative year volumes related to surface water diversions and groundwater extractions were restated from the 2015–2018 Accounts due to a change in presentation. Previously, these abstractions were not considered to be associated with an allocation; however, in this account they have been reclassified as allocated abstractions. The comparative year items restated in this account include:

  • Allocated extraction: individual users
  • Allocated diversion: individual users
  • Non-allocated extraction: individual users
  • Non-allocated diversion: individual users.

 

Inter-region delivery

Comparative year volumes related to inter-region delivery were restated from the 2017 and 2018 Accounts due to a prior period error. In these previous accounts, it was incorrectly assumed that an inter-region delivery to the urban system had occurred during these two years. This volume has been restated as zero in this account.

 

Daly

Water liability

Comparative year volumes related to water liability were restated from the 2015 Account due to a change in presentation. The change in presentation refers to the alignment of the reporting year in the National Water Account (1 July–30 June) with the Department of Environment and Natural Resources licence water year (1 May–30 April). This means that licence data (including allocations and water use) aligns with that reported by the department, providing consistent and clearer information to users of the Account. The comparative year items restated in this account include:

  • Allocation remaining
  • Allocated diversions
  • Allocated extractions
  • Unaccounted-for difference
  • Change in net water assets.

 

Unaccounted-for difference

Comparative year volumes related to unaccounted-for difference were also restated from the 2015 Account due to a change in presentation. This change in presentation separated the actual change in aquifer storage from the unaccounted-for difference volume in the water accounting statements. Previously, unaccounted-for difference included changes in water storage. Change in aquifer storage is now presented within the change in net water assets (and change in water storage) item in the statements. The comparative year items restated in this account include:

  • Unaccounted-for difference
  • Change in net water assets.

 

Fitzroy

Surface water store

Comparative year volumes related to surface water storage were restated from the 2017 and 2018 Accounts due to a change in presentation. In these accounts, the total storage volume included storages where data were not available and were assumed to be at capacity. These storages make up less than 6% of the region's total storage capacity and are no longer included in the account. The comparative year items restated in this account include:

  • Storages
  • Unaccounted-for difference
  • Change in net water assets
  • Closing net water assets.

 

Melbourne

Surface water store

Comparative year volumes related to the surface water store were restated from the 2015–2018 Accounts due to a change in presentation. In previous accounts, Thomson Reservoir was not considered as a surface water asset for the region as it is located outside of the region boundary. In this account, however, given that the reservoir is primarily used as water supply for the region's urban water system, Thomson Reservoir has been included as a water asset. The comparative year items restated in this account include:

  • Storages
  • Precipitation
  • Evaporation
  • Inter-region inflow
  • Delivery: inter-region
  • Claims: inter-region.

Additional items such as river storage, runoff, flood return, overbank flow, outflow, and groundwater recharge were also restated in this account using an updated methodology. These items were not directly affected by the inclusion of Thomson Reservoir as an asset; however, these items were important to change given their relationship to the items listed above.

 

Water diversions

The following comparative year volumes related to water use were restated from the 2017 Account due to prior period errors:

  • Allocation remaining: individual users
  • Allocated diversion: individual users
  • Non-allocated diversion: individual users.

 

Urban water system

Comparative year volumes for some urban flow volumes were restated from the 2015 Account due to a change in presentation associated with amendments to the Water Regulations. Leakage from the urban system to either groundwater and the landscape, previously two separate items, were reclassified as a single leakage item in the 2016 Account.

 

Murray-Darling Basin

Surface water store

Comparative year volumes related to the surface water store were restated from the 2014–2018 Accounts due to a change in presentation. In previous accounts, several of the region's smaller reservoirs were considered as surface water assets; however, these storages were not included in the Murray–Darling Basin Authority (MDBA) reports. To better align with the MDBA, these smaller reservoirs are no longer included as a water asset. The comparative year items restated in this account include:

  • Storages
  • Precipitation
  • Evaporation.

Additional items such as river storage, lakes and wetlands, runoff, flood return, overbank flow, outflow, and inter-region inflow were also restated in this account using an updated methodology. These items were not directly affected by the exclusion of the smaller reservoirs as an asset; however, these items were important to change given their relationship to the items listed above.

In addition, the accessible storage and dead storage volumes are now presented in the water accounting statements, rather than just the total water storage, to also better align with the MDBA reports.

 

Water extractions and overbank flow

The following comparative year volumes related to groundwater use and overbank flow were restated from the 2017 Account due to a change in presentation. The change in presentation included the separation of groundwater supply for salinity and water table management from groundwater supply to individual users. In addition, overland flow take was separated from overbank flow, where previously these items were classified as a single flow. The comparative year items restated in this account include:

  • Allocated extraction: individual users
  • Allocated extraction: salinity and water table management
  • Overbank flow
  • Overland flow take.

 

Prior period errors

The comparative year volume of groundwater allocation remaining: individual users was restated from the 2018 Account due to a prior period error.

 

Ord

Water diversions

Comparative year volumes related to surface water liability were restated from the 2015–2018 Accounts due to a prior period error. In the 2015 and 2016 Accounts, allocated diversion to the irrigation scheme was incorrectly estimated using on-farm use in the Ord Irrigation Area, rather than the total volume of water diverted to the area from Lake Kununurra. Similarly, allocated diversion to an individual user was also incorrectly estimated using on-farm data rather than the volume diverted from surface water. In the 2017 and 2018 Accounts, allocated diversion to the irrigation scheme was incorrectly calculated using metered data from a diversion point already included in the metered data from the M1 offtake channel.

The comparative year items restated in this account include:

  • Allocation remaining: irrigation
  • Allocated diversion: irrigation
  • Allocation remaining: individual users
  • Allocated diversion: individual users
  • Unaccounted-for difference
  • Change in net water assets
  • Closing net water assets.

 

Perth

Region boundary change

Comparative year volumes related to the irrigation scheme were restated from the 2015 and 2016 Accounts due to a region boundary change. The Perth region boundary was extended for the purpose of incorporating the full extent of the Harvey Water Irrigation Area, including the Wellington Reservoir. The comparative year items restated in this account include:

  • Storages (surface water)
  • *Irrigation scheme claims: surface water (asset)
  • *Allocation remaining: irrigation scheme
  • Delivery: inter-region (surface water)
  • Delivery: irrigation scheme
  • Leakage: landscape (irrigation scheme)

*These items are between-store claims that were not reported in the statements prior to the 2018 Account but did appear in the notes.

 

Urban water system

Comparative year volumes relating to some urban flow volumes were also restated from the 2015 and 2016 Accounts due to a change in presentation. This change in presentation separated supply system discharges to reservoirs from those to rivers as a riparian release. Previously, these flows were classified as a single flow from the urban system. In addition, groundwater replenishment from the urban system as either discharge to groundwater or managed aquifer recharge was reclassified as a single aquifer recharge item. The comparative year items restated in this account include:

  • Supply system discharge: reservoirs
  • Supply system discharge: riparian release
  • Managed aquifer recharge

As these are between-store flows, they were not previously reported in the statements but did appear in the notes prior to the 2018 Account.

 

Groundwater store

Comparative year volumes for the change in groundwater storage were restated from the 2018 Account due to a change in presentation. In the 2018 Account, the change in aquifer storage was separate to the unaccounted-for difference and, given that the groundwater storage cannot be quantified, this meant that the water accounting statements did not balance. The 2018 comparative year volumes have been restated to include the actual change in aquifer storage within the unaccounted-for difference volume.

Comparative year volumes for groundwater inter-region coastal outflow were restated from the 2015 and 2016 Accounts due to a calculation error.

 

Unaccounted-for difference

The unaccounted-for difference for 2015–2018 Accounts was also restated as a result of the changes described above.

 

South East Queensland

Water diversions

Comparative year volumes related to non-allocated surface water diversions were restated from the 2018 Account due to a prior period error. The reported volume for non-allocated diversion to the urban water system incorrectly included groundwater extraction data. The comparative year items restated in this account include:

  • Non-allocated diversion: surface water
  • Non-allocated diversion: urban system

 

Sydney

Groundwater store

Comparative year volumes related to the groundwater store were restated from the 2015–2018 Accounts due to a change in presentation. Flows into and out of the groundwater store, as well as water entitlement information associated with groundwater extractions, were previously not reported in the accounts. The comparative year items restated in this account include:

  • Allocated extraction
  • Recharge: surface water
  • Leakage: urban
  • Unaccounted-for difference.

 

Urban water system

Comparative year volumes for several urban flow volumes were also restated from the 2015 Account due to a change in presentation associated with amendments to the Water Regulations in 2016. A primary aim of these amendments was to reduce reporting burden on urban utilities and town councils. This change in presentation included the removal of inter-region water transfers and deliveries associated with small town council areas that lie partly outside the Sydney region boundary.