Murray–Darling Basin
Water accounting policies
- Introduction
- Recognition of water assets and water liabilities
- Recognition of changes in water assets and water liabilities
- Water assets and water liabilities that fail the recognition criteria
- Changes to water assets and water liabilities that fail the recognition criteria
- Restatement of comparative year information
- Level of reporting in case of bulk entitlements in Victoria
- Treatment of water trade
- Treatment of external transfers
Introduction
The information presented in the Murray–Darling Basin (MDB) 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.
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 megalitres (ML). Where a reported volume is negative, it is shown in brackets.
Recognition of water assets and water liabilities
Only water that is held or managed by the jurisdictional licensing authority and from which future benefit can be derived by stakeholders of the region is identified 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 providing:
- its 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 providing:
- its volume can be quantified in a way that is complete, neutral, and free from material error
- the decrease of the region's water assets to supply water is probable.
Water held in off-channel water storages that has already been abstracted from the entitlement system is part of the region (regardless of the storage's size or connection to the system) but is not part of the region's water account. This is because the attendant water right has already been exercised.
The volume of Other groundwater assets included in the water accounting statements has been recognised as the long-term estimates of volumes for extraction (including New South Wales supplementary access licences for the specific year) plus basic landowner right of groundwater, representing the extractable portion that is required under the Australian Water Accounting Standard 1 (Bureau 2012).
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 only in relation to the storage surfaces which include storages, lakes, weirs, and locks in the regulated river). It does 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 is quantified and recognised. This runoff includes precipitation captured in the catchment less estimated evaporation and seepage and is recorded as Runoff to surface water.
The volume of water that returns after urban use, recorded as Discharge from urban water supply 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 Flows, and information is provided in the Notes.
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 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, and more information is provided in the Notes.
Water assets and water liabilities that fail the recognition criteria
The volumes of some water assets and water liabilities in the MDB 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
- in the case of water assets, they were unlikely to provide a future benefit to the region or the region's stakeholders
- in the case of water liabilities, they were unlikely to result in a decrease in the region's water assets or an increase in another water liability when the obligation is discharged.
While water within Unregulated river is a vital water asset for the conveyance of water within the region, it cannot be quantified accurately due to a lack of reliable information.
Details of volumes of water stored in lakes and wetlands are available for Lakes and wetlands. The line item includes information only for nine lakes. Volume of water stored in other lakes and wetlands was not available.
The description of other water assets and water liabilities that failed the recognition criteria is given under Water table aquifer and Underlying aquifers.
Changes to water assets and water liabilities that fail the recognition criteria
The volumes of changes to several water assets and water liabilities identified in the MDB 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 (Bureau 2012), because they could not be quantified in a way that is complete, neutral, and free from material error.
The description of those changes to water assets and water liabilities that failed the recognition criteria is given in Supporting information note and are
- overbank flood return to river channel
- direct discharge by user
- leakage from off-channel water storage
- leakage from urban water system
- leakage from irrigation scheme
- leakage to landscape.
These volumes that could not be quantified form part of:
- river and floodplain leakage, evaporation and errors
- unaccounted-for difference.
Restatement of comparative year information
In accordance with the Australian Water Accounting Standard 1 (Bureau 2012), comparative year volumes must be restated in the 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 scope or methodology or subsequent data availability for the quantification of a line item. The following comparative year volume in the water accounting statements was restated from the 2013 Account.
| Account | Correct 2013 volume in 2014 Account (ML) | Incorrect volume in 2013 Account (ML) | Difference (ML) | Reasons for the difference |
| Surface water assets | ||||
| Storages | 16,021,763 | 16,011,790 | 9,973 | reclassification of Jack Taylor Weir under storages to align with online storage information published by Murray–Darling Basin Authority (MDBA) |
| Regulated river | 1,009,288 | 1,019,262 | (9,974) | reclassification of Jack Taylor Weir under storages to align with online storage information published by MDBA |
| Surface water liability | ||||
| Surface water allocation remaining | 4,346,391 | 4,204,314 | 142,077 | information updated by the jurisdictions in their data provision to MDBA under provisions made in s71 of the Water Act |
| Groundwater liability | ||||
| Groundwater allocation remaining | 2,404 | 1,907 | 497 | inclusion of groundwater liability for Marne Saunders as received from South Australian Department of Environment, Water and Natural Resources |
| Surface water inflows | ||||
| Precipitation on surface water | 1,155,617 | 1,160,129 | (4,512) | calculation correction made to precipitation at upstream of Lake Mulwala (4,507 ML) and rounding-off error (5 ML) |
| Adjustment and forfeiture of surface water allocation | ||||
| Adjustment and forfeiture of surface water allocation: individual users | 1,165,564 | 2,007,538 | (841,974) | Ajustment and forfeiture is based on balancing carryover, allocation announcements, allocation diversions and temporary trade volumes. Changes made to these variables have resulted in differences between updated and reported adjustment and forfeiture volumes. |
| Adjustment and forfeiture of surface water allocation: urban water system | 169,589 | 173,439 | (3,850) | Adjustment and forfeiture is based on balancing carryover, allocation announcements, allocation diversions and temporary trade volumes. Changes made to these variables have resulted in differences between updated and reported (2013 Account) adjustment and forfeiture volumes. |
| Adjustment and forfeiture of groundwater allocation | ||||
| Adjustment and forfeiture of groundwater allocation: individual users | 1,204,745 | 1,205,242 | (497) | Adjustment and forfeiture is based on balancing carryover, allocation announcements and allocation diversions. Changes made to these variables have resulted in differences between updated and reported adjustment and forfeiture volumes. |
| Adjustment and forfeiture of groundwater allocation: urban water system | 31,633 | 31,792 | (159) | Adjustment and forfeiture is based on balancing carryover, allocation announcements and allocation diversions. Changes made to these variables have resulted in differences between updated and reported adjustment and forfeiture volumes. |
| Surface water outflows | ||||
| Evaporation from surface water | 3,021,950 | 3,036,866 | (14,915) | calculation correction made to evaporation at upstream of Lake Mulwala |
| River outflow from the region | 5,267,000 | 5,179,600 | 87,400 | information based on MDBA's updated calculations |
| Entitled diversion on non-allocated surface water to users | 2,137,025 | 2,066,946 | 70,079 |
|
| Entitled diversion of non-allocated surface water to urban water system | 19,880 | 13,073 | 6,807 | inclusion of non-allocated urban water use for New South Wales |
| River and floodplain leakage, evaporation and errors | 12,618,361 | 14,499,374 | (1,881,013) | River and floodplain leakage, evaporation and errors is based on water balance of all other surface water store variables. Updates made to these variables have resulted in a difference between the updated and reported volumes in the 2013 Account for the 2012–13 year for river and floodplain leakage, evaporation and errors. |
| Entitled diversion of allocated surface water to users | 10,571,312 | 8,844,177 | 1,727,135 | The volume has been adjusted to include system losses. |
| Entitled diversion of allocated surface water to urban water system | 365,595 | 365,598 | (3) | rounding-off error (1 ML) and New South Wales Murrumbidgee WRP area correction (–4 ML) |
| Groundwater outflows | ||||
| Entitled extraction of allocated groundwater to urban water system | 37,096 | 37,024 | 72 | Adjusted 71 ML water use for Kanmantoo Fold Belt SDL area in the 2013 Account and correction of rounding-off error (1 ML). |
| Surface water allocation | ||||
| Surface water allocation announcements: individual users | 8,785,815 | 7,758,577 | 1,027,238 | information updated by the jurisdictions in their data provision to MDBA under s71 of the Water Act |
| Surface water allocation announcements: urban system | 535,184 | 539,037 | (3,853) | information updated by the jurisdictions in their data provision to MDBA under s71 of the Water Act |
| Groundwater allocation | ||||
| Groundwater allocation announcements: urban system | 68,729 | 68,816 | (87) | overestimated allocation in the 2013 Account for Lower Murray Alluvium SDL area |
| Unaccounted-for difference | ||||
| Unaccounted-for difference | (2,280,386) | (2,280,313) | (73) | overestimation of the unaccounted for diffrerence in the 2013 Account as a result of not including 71 ML groundwater use for Kanmantoo Fold Belt SDL area |
Level of reporting in case of bulk entitlements in Victoria
When water is managed under a bulk entitlement in Victoria (see Water management plans and Water entitlements under 'Contextual information'), the 2014 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.
Treatment of water trade
It is assumed that all water traded (allocation trade) within the MDB region has been provided to an account holder within the region, even though delivery may be provided via the distribution network to a location outside of the region.
Water trades are not reported in the water accounting statements; however, some water trades result in the conversion of the category and purpose of use, which will affect their classification. It is believed these effects are reflected in relevant information for allocation remaining, allocation announcements, allocation diversion, and forfeiture and adjustments in the water accounting statements.
Information about interstate, inter-valley and intra-valley trade is included in the Water market activity note.
Treatment of external transfers
Transfers of water that occur across the boundaries of the MDB 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 'Surface water store' notes.
The following external transfers are reported in the water accounting statements:
- import from the Glenelg River (appears as an inter-basin transfer)
- import from the Snowy Mountains scheme (appears as an inter-basin transfer).
The following transfers form part of allocation diversion volumes and are not reported separately in the water accounting statements:
- export to Sydney region from the Fish River system in the Macquarie River system
- export to Metropolitan Adelaide and associated country areas
- export to Melbourne (diversion made under commercial agreement from the Goulburn–Broken River system)
- water transfers from the Goulburn–Broken River system to Ballarat (in the Barwon River system) via 'Goldfields superpipe'
- water transfers from the Goulburn–Broken River system (from Silver and Wallaby creeks, which are tributaries of the Goulburn River) to the Melbourne urban supply system.
Import from South East Queensland region is not reported in the water accounting statements as it is a direct import by the Toowoomba Regional Council distribution system, which is not considered part of the region.