Adelaide
9.3 Groundwater discharge

Supporting Information

The volume reported (72,148 ML) represents annual average groundwater discharge (baseflow) to watercourses in the Adelaide region. This volume included annual baseflow from groundwater to watercourses within the Western Mount Lofty Ranges Prescribed Water Resources Area (70,655 ML) and baseflow at the Yaldara gauging station on the North Para River (1,493 ML) as shown in the following table.

Groundwater discharge to surface water itemised by underground water management zones
Underground water management zones Baseflow (ML)
Lower South Para (inc. Lower Gawler River) 1,351
Middle South Para River 3,784
Upper South Para River (Adelaidean) 1,538
Upper South Para River (Kanmantoo) 660
Gould Creek 460
Little Para Reservoir 209
Lower Little Para River 87
Upper Little Para River 1,407
Kersbrook Creek 1,428
Mount Pleasant 300
Birdwood 1,273
Hannaford Creek 416
Angas Creek 587
Millers Creek 604
Gumeracha 1,079
McCormick Creek 257
Footes Creek 283
Kenton Valley 420
Cudlee Creek 882
Kangaroo Creek Reservoir 1,330
Sixth Creek 2,809
Charleston Kanmantoo 652
Inverbrackie Creek Kanmantoo 305
Charleston Adelaidean 979
Inverbrackie Creek Adelaidean 567
Mitchell Creek 155
Western Branch 998
Lenswood Creek 2,182
Upper Onkaparinga 1,906
Balhannah 220
Hahndorf 355
Cox Creek 2,029
Aldgate Creek 1,846
Scott Creek 1,487
Chandlers Hill  373
Mount Bold Reservoir 2,644
Biggs Flat 323
Echunga Creek 1,063
Myponga Adelaidean 1,781
Myponga Sedimentary 3,303
Hindmarsh Fractured Rock 6,484
Hindmarsh Tiers Sedimentary 1,372
Fleurieu Permian 6,781
Southern Fleurieu North 4,013
Southern Fleurieu South 7,673
Western Mount Lofty Ranges Subtotal  70,655 
North Para River at Yaldara  1,493
Total 72,148 

Quantification Approach

Data Source

South Australian Department for Water: Hydstra database; and Draft Water Allocation Plan for the Western Mount Lofty Ranges Prescribed Water Resources Area (PWRA).

Provided by

South Australian Department for Water.

Method

Groundwater discharge to surface water was summed from the annual baseflow figures stated in the Draft Water Allocation Plan for the Western Mount Lofty Ranges PWRA (70,655 ML) and baseflow at the Yaldara gauging station on the North Para River (1,493 ML).

The stream gauge for the North Para River at Yaldara (A5050502) was deemed the only streamflow site with a significant baseflow component outside the Western Mount Lofty Ranges PWRA. Baseflow was calculated for this site using a Lyne and Hollick filter (Grayson et al. 1996) with a filtering factor of 0.925 and daily flow records for 1 July 1975 to 30 June 2010.

Assumptions, Limitations, Caveats and Approximations

  • Baseflow at the gauging stations captured all the surface water–groundwater interactions in the catchment.
  • Baseflow identified by the Lyne and Hollick filter was entirely due to contributions from groundwater.
  • Long-term baseflow represents the flux during the 2010–11 year.
  • Groundwater discharge to connected surface water was the dominant process in the Western Mount Lofty Ranges.
  • Surface water–groundwater interactions outside the draft Western Mount Lofty Ranges PWRA and the catchment for Yaldara gauge are negligible.

 

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This line item corresponds to line item 13.3 Groundwater discharge to connected surface water, reported in the 2010 Account. There was no change to the volume reported in the 2010 Account. The restated comparative year volume is 72,148 ML.