6.1 Groundwater allocation remaining
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:
- Barossa Prescribed Water Resources Area (PWRA) Water Allocation Plan
- McLaren Vale Prescribed Wells Area (PWA) Water Allocation Plan
- Northern Adelaide Plains Prescribed Wells Area (PWA) Water Allocation Plan.
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.
|Calculation||Line item||Volume (ML)
|Opening balance||6.1 Groundwater allocation remaining|
|6.1 Groundwater allocation remaining
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.
|Category||Prescribed area||2009–10 (ML)||2010–11 (ML)|
|Native groundwater – rollover from prior year||Barossa PWRA||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
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.
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 184.108.40.206 Groundwater allocation remaining – individual irrigator holder, 220.127.116.11 Groundwater allocation remaining – industrial and commercial holder, and 18.104.22.168 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.
|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|