22.1 Groundwater allocation announcements
During the 2010–11 year the volume of groundwater available for extraction increased by 41,555 ML. This volume included native groundwater allocations and recharged water credits that were available to be extracted during 2010–11.
- Native groundwater allocations are renewed each reporting period where the full allocation volume detailed by the user's license is available for the user to extract.
- Recharged water credits are allocated based on the volume injected as part of managed aquifer recharge (MAR). A portion of the volume of water injected in a prior recharge period is allocated for reuse, called a recharged water credit. The recharged water credit volume may also depend on the quality of the water discharged.
More information about native groundwater allocations and recharged water credits can be found in the Water allocations section of the Contextual information.
For more information on this groundwater liability see line item 6.1 Groundwater allocation remaining.
Groundwater allocations for the 2010–11 year were obtained from the WILMA database for the following water management areas in the Adelaide region:
- Barossa Prescribed Water Resources Area (PWRA)
- McLaren Vale Prescribed Wells Area (PWA)
- Northern Adelaide Plains PWA.
Allocations for the Barossa PWRA that are area-based were converted to volumes using the guidelines on p35 of the Barossa Water Allocation Plan.
The Department for Water database detailing MAR credit calculations was used to differentiate new recharged water credits from previously applied but not used or not expired recharged water credits carried over to 2010–11 (6.1 Groundwater allocation remaining). New recharged water credits relate to practices completed only in the previous recharge period. In the Northern Adelaide Plains PWA the previous recharge period was 1 July 2009 to 30 June 2010. In the McLaren Vale PWA the previous recharge period was 1 October 2009 to 30 April 2010.
|Category||Prescribed area||Original purpose*||Allocation volume (ML)|
|Native groundwater||Barossa PWRA||Irrigation (area-based)||285|
|McLaren Vale PWA||NA||6,544|
|Northern Adelaide Plains PWA||Industrial||1,478|
|Stock and domestic||199|
|Recharged water||Barossa PWRA||NA||0|
|McLaren Vale PWA||NA||0|
|Northern Adelaide Plains PWA||NA||1,125|
*The licence purpose information for the Northern Adelaide Plains PWA and Barossa PWRA reflects the purpose of the licence when issued or possibly when adjusted. Purpose information was not available (NA) for the McLaren Vale PWA.
Assumptions, Limitations, Caveats and Approximations
- The method assumed that irrigation crop area conversion rates stated in Table 15 of the Barossa PWRA Water Allocation Plan represent an equivalent volumetric allocation.
- Some irrigators can negotiate different conversion rates based on individual circumstances.
This corresponds to the subcategories of line item 27.1 Groundwater allocation announcement 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 announcement – individual irrigator holder, 220.127.116.11 Groundwater allocation announcement – industrial and commercial holder and 18.104.22.168 Groundwater allocation announcement – individual holder for stock and domestic were merged into a single line item 22.1 Groundwater allocation announcement.
- Change in scope: in the 2011 Account, the groundwater liability reported included recharged water credits, whereas it was 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. Data regarding recharged water credits during the 2009–10 year were not available. Therefore the restated comparative year volume only included native groundwater allocations. The restated comparative year volume is 39,236 ML.