Adelaide
18.4 Discharge to surface water
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.
| 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
Hydstra database, and draft water allocation plan for the Western Mount Lofty Ranges Prescribed Water Resources Area (PWRA).
Provided by
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 WMLR 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 – 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 2011–12 year.
- Groundwater discharge to connected surface water was the dominant process in the WMLR.
- Surface water—groundwater interactions outside the draft WMLR PWRA and the catchment for Yaldara gauge are negligible.