Adelaide
18.11 Groundwater allocation extraction

Supporting Information

The volume of groundwater extracted under the groundwater liability during 2010–11 was 15,019 ML. The volume of groundwater extractions could not be quantified individually for native and recharged groundwater. The groundwater extraction volume decreased considerably compared to the previous reporting period (2009–10: 20,136 ML).

For more information on this groundwater liability see line item 6.1 Groundwater allocation remaining.

Quantification Approach

Data Source

South Australian Department for Water: Water Information and Licence Management Administration System (WILMA) database and Drillhole Enquiry System.

Provided by

South Australian Department for Water.

Method

Barossa Prescribed Water Resources Area (PWRA)

Metered extraction was obtained from the WILMA licensing database and linked to Drillhole Enquiry System records via the Unit ID to obtain the aquifer.

Some groundwater extraction was unmetered in the Barossa PWRA. Metered groundwater extraction in the Barossa was increased based on the assumption that 20% of the total extraction was unmetered.

McLaren Vale Prescribed Wells Area (PWA)

Metered extraction was obtained from the WILMA licensing database and linked to Drillhole Enquiry System records via the Unit ID to obtain the aquifer.

Northern Adelaide Plains PWA

Metered extraction was obtained from the WILMA licensing database and summarised by the aquifer listed.

Metered groundwater allocation extractions in the Adelaide region during the 2010–11 year
Prescribed area Aquifer Volume (ML)
Barossa PWRA Fractured rock 710
Upper Aquifer 100
Lower Aquifer 226
Unknown 74
Correction for unmetered extraction 277
Subtotal   1,387
McLaren Vale PWA Fractured rock 333
Maslin Sands (T2) 342
Port Willunga and Blanche Point Formation (T1) 1,658
Quaternary Aquifer 2
Unknown 194
Subtotal   2,529
Northern Adelaide Plains PWA Quaternary (Q1) 1
Quaternary (Q2) 37
Quaternary (Q3) 234
Quaternary (Q4) 71
Tertiary T1 3,133
Tertiary T2 7,555
Unknown 72
Subtotal   11,103
Total   15,019

 

Assumptions, Limitations, Caveats and Approximations

Unmetered groundwater extraction in the Barossa PWRA was assumed to equate to 20% of total extraction. This was based on the assessment by water licensing staff members that the proportion would be similar to the previous year.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This corresponds to the subcategories of line item 16.5 Groundwater allocation extraction 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 16.5.3.2 Groundwater allocation extraction – individual irrigator holder, 16.5.3.3 Groundwater allocation extraction – industrial and commercial holder and 16.5.3.5 Groundwater allocation extraction – individual holder for stock and domestic were merged into a single line item 22.1 Groundwater allocation extraction.

Despite these changes the volume reported in the 2010 Account did not change. The comparative year volume is 20,336 ML.