Adelaide
6.1 Groundwater allocation remaining

Supporting Information

In the Adelaide region groundwater rights that create a water liability include allocations of native groundwater and recharged groundwater:

  • Native groundwater occurs underground as a result of natural processes.
  • Recharged groundwater refers to water that is actively discharged to groundwater. Following a period of time termed a 'recharge' period, a portion of this water is made available for reuse. This arrangement is called managed aquifer recharge (MAR).

In the Adelaide region native groundwater allocations in areas with an operational water allocation plan are provided by a water licence. These water licences are managed under the relevant water allocation plan that describes the licence operating conditions including water allocations and carryover rules:

Other groundwater water resources in the Adelaide region that do not have a water allocation plan are managed by a Notice of Prohibition. Under that type of management arrangement, no water liability is created prior to the extraction taking place (see line item 18.7 Extraction – other statutory right).

For further information on groundwater extractions that create a liability see line item 33.3 Groundwater access entitlement for allocation extraction.

The opening balance for groundwater allocation remaining was 2,857 ML and included rollover of native groundwater allocations and recharged water allocations that were carried forward from the 2009–10 year. The equivalent volume reported as the closing balance for the 2010–11 year (3,561 ML) did not include native groundwater rollover for the Barossa PWRA as these data were not available at the time this report was compiled. Therefore no meaningful comparisons of rollover volumes between years can be made.

The carryover balance (allocation remaining) of the groundwater liability, increases due to allocation announcements, physical extractions of allocated water and the volume of water forfeited at the end of the 2010–11 year are provided in the following table. Links to these related line items are also provided.

Groundwater liability calculations in the 2010–11 year
Calculation Line item Volume (ML)
Opening balance 6.1 Groundwater allocation remaining  
Native groundwater 1,380
Recharged groundwater 1,477
Total 2,857
add

22.1 Groundwater allocation announcement

 
Native groundwater 40,430
Recharged groundwater 1,125
Total 41,555
less

18.11 Groundwater allocation extraction

15,019
less

14.1 Adjustment and forfeiture of groundwater allocation

25,832
Closing
balance
6.1 Groundwater allocation remaining
 
Native groundwater 1,665
Recharged groundwater 1,896
Total 3,561

Quantification Approach

Data Source

South Australian Department for Water: Water Information and Licence Management Administration (WILMA) database; and database detailing managed aquifer recharge credit calculations.

Provided by

South Australian Department for Water.

Method

Native water allocation

Carryover of native groundwater allocations for the 2009–10 and 2010–11 years was extracted from the WILMA licensing database. Carryover of native groundwater allocations was available for the McLaren Vale Prescribed Wells Area (PWA), but not for the Barossa Prescribed Water Resources Area (PWRA).

Recharged water credits

The Department for Water database detailing managed aquifer recharge credit calculations was used to differentiate new recharged water credits (line item 22.1 Groundwater allocation announcements) from previously applied but not used or not expired recharged water credits carried over to the 2010–11 year. Recharged water credits to be carried forward to the 2010–11 year relate to practices completed in the period preceding the previous recharge period. The relevant water allocation plan suggests that the period preceding the previous recharge period is:

  • Northern Adelaide Plains PWA: July 1 2005 to June 30 2009 
  • McLaren Vale PWA: May 1 2007 to September 30 2009.
Groundwater allocation remaining by category and management area
Category  Prescribed area 2009–10 (ML) 2010–11 (ML)
Native groundwater – rollover from prior year Barossa PWRA 0
0
McLaren Vale PWA 1,380 1,665
Northern Adelaide Plains PWA 0 0
Recharged water credits –  to be carried forward  Barossa PWRA 0 0
McLaren Vale PWA 14 10
Northern Adelaide Plains PWA 1,463 1,886
Total 2,857
3,561

Assumptions, Limitations, Caveats and Approximations

In some situations the operating rules applicable to managed aquifer recharge schemes were created under Environment Protection Authority guidance and may differ from the content of the relevant water allocation plan.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This corresponds to the sub-categories of line item 9.1 Groundwater allocation remaining reported in the 2010 Account. In the 2011 Account, the following changes were made that caused the 2009–10 year value to be restated:

  • The presentation of the line items has changed since the 2010 Account: line items 9.1.3.2 Groundwater allocation remaining – individual irrigator holder, 9.1.3.3 Groundwater allocation remaining – industrial and commercial holder, and 9.1.3.2 Groundwater allocation remaining – individual holder for stock and domestic were merged into a single line item: 6.1 Groundwater allocation remaining.
  • Change in scope: in the 2011 Account, the groundwater liability reported included recharged water credits, whereas these were not reported as a groundwater liability in the 2010 Account.

Restatement of the volume published in the 2010 Account was made as the difference from these changes was material and increased the accuracy of the information provided to the users of the National Water Account. The changes and their respective volumes are detailed in the following table. The restated comparative year opening balance is 1,184 ML and closing balance is 2,857 ML.

Restatement of comparative year information for line item 6.1 Groundwater allocation remaining
2010 Account line item name Groundwater category Volume at 30 June 2010 reported in 2010 Account (ML) Value difference due to changes (ML) Volume at 30 June 2010 reported in 2011 Account (ML)
Opening balance Closing balance Opening balance Closing balance Opening balance Closing balance
9.1 Groundwater allocation remaining Native groundwater rollover credits 1,184 1,388   (8) 1,184 1,380
Recharged water credit   1,477 1,477
Total

1,184
1,388
0
1,469
1,184
2,857