Adelaide

                                                                                                   

2.3 Aquifers—other lumped

                             

Supporting information   


The volume reported in the water accounting statement (39,268 ML) represents the allocated groundwater resources for the Adelaide region as at 30 June 2010. The allocated groundwater resources are itemised by management area in the table below.

Management area

Allocated volume (ML)

Barossa Prescribed Water Resource Area

7,580

McLaren Vale Prescribed Wells Area

6,506

Northern Adelaide Plains Prescribed Wells Area

25,182

Total

39,268

The groundwater asset in the Adelaide region has been equated to the total volume of allocated groundwater in the prescribed areas of the Adelaide Region, specifically:

  • Barossa Prescribed Water Resource Area (PWRA)
  • McLaren Vale Prescribed Wells Area (PWA)
  • Northern Adelaide Plains PWA.

Groundwater resources that service stock and domestic licences have not been included in this volume, except in the Northern Adelaide Plains PWA where groundwater is allocated for stock and domestic use. Elsewhere, stock and domestic use of groundwater is considered a basic right and is not allocated as an annual volume for extraction, including in the Barossa PWRA and McLaren Vale PWA.

Neither has the non-extractable portion of groundwater within the prescribed areas been recognised as a groundwater asset. It is, however, considered to be a contingent water asset, which cannot currently be accessed due to physical and regulatory constraints. In addition, groundwater resources covered by a Notice of Prohibition, such as the aquifers of the Western Mount Lofty Ranges or groundwater resources not declared as prescribed, have not been recognised as water assets. Groundwater is extracted from these aquifers for irrigation and industrial use (as well as stock and domestic supply). However, the extractable portion of groundwater cannot be quantified adequately and therefore cannot be recognised as a water asset on the Statement of Water Assets and Water Liabilities. Additional information on these groundwater assets can be found in Contingent water assets and contingent water liabilities and Water Assets and Water Liabilities that Fail the Recognition Criteria.

The volume of groundwater asset could only be determined by management area and not by aquifer because some licences apply to multiple aquifers. The percentage of extraction bores in each aquifer is presented in the table below to indicate the level of development of the various aquifers within each management area. Most extraction bores occur in:

  • Port Willunga Formation in the McLaren Vale PWA
  • Fractured Rock and Lower Aquifer in the Barossa PWRA
  • T2 aquifer in the Northern Adelaide Plains PWA.

 

Management area

Aquifer type

Aquifer

Percentage of extraction (by management area)

McLaren Vale Prescribed Wells Area

Generally unconfined or semi-confined

Quaternary Sediments

<1

Generally unconfined or semi-confined

Port Willunga Formation

59

Confined

Maslin Sands

17

Generally confined

Fractured Rock

18

Not specified

Unknown

5

Barossa Prescribed Water Resources Area

Generally unconfined or semi-confined

Upper Aquifer

12

Confined

Lower Aquifer

29

Confined and Unconfined

Fractured Rock

47

Not specified

Unknown

12

Northern Adelaide Plains Prescribed Wells Area

Generally unconfined or semi-confined

Q1, Q2, Q3 (Quaternary)

2

Confined

Q4

(Quaternary)

1

Generally confined or semi-confined

T1

(Tertiary)

20

Confined

T2

(Tertiary)

76

Confined

Fractured Rock

1

Not specified

Unknown

<1

Source:  Cobb 1986, NABCWMB 2000, Brown 2002, AMLRNRMB 2007, AMLRNRMB 2009

 

Quantification approach   


Data source

South Australian Department for Water: Water Information and Licensing Management Application (WILMA) database.

Adelaide and Mount Lofty Ranges Natural Resources Management Board (AMLRNRMB): Water Allocation Plan for the Barossa Prescribed Water Resources (2009).

 

Data provider

South Australian Department for Water.

 

Method

The aquifer store has been equated to the total volume of allocated groundwater as recorded in the WILMA database for the prescribed groundwater resources in the Adelaide Region. The calculation includes volumetric allocations, area-based allocations, and metered stock and domestic use. The area-based allocations have been converted to a volume based on the default values specified in the Water Allocation Plan (AMLRNRMB 2009).

 

Uncertainty

Ungraded.

 

Assumptions, approximations and caveats/limitations

Allocation adjustments due to recharged water and allocations carried over from previous years have not been included in the aquifer store.