NCRIS Groundwater Infrastructure

Willunga

Where is Willunga?

The Willunga Basin is located approximately 25 kilometres south of Adelaide in South Australia, and incorporates the towns of Willunga, McLaren Vale, McLaren Flat, Kangarilla, Aldinga, Port Willunga and Sellicks Beach. The basin structure is a gently-dipping trough, bounded to the east and south by the steeply-dipping Willunga Fault and St Vincent’s Gulf to the west.  The four main aquifers within the Willunga Basin are the unconfined Quaternary aquifer (comprised of sands, gravels and interbedded clays), the confined Port Willunga Formation aquifer (loosely consolidated sands and indurated limestone), the confined Maslin Sands aquifer (very fine to coarse sands) and a fractured basement rock aquifer. Mean annual rainfall in the basin ranges from 641 mm at Willunga to 717 mm at Mt Bold Reservoir.

Why is this location important?

The Willunga Basin comprises a thick sequence of Cainozoic sediments that provide critical groundwater supplies for the established wine and horticulture industries in the McLaren Vale region. Groundwater extraction within the McLaren Vale Prescribed Wells Area (PWA), which encompasses the Willunga Basin, is currently managed through a Water Allocation Plan under the South Australian Natural Resources Management Act, 2004. Metered groundwater extractions in the McLaren Vale PWA were 3,990 ML for 2009-10.  Most of this extraction is from the Port Willunga Formation Aquifer (65%), with 18% taken from the Maslin Sands and 17% from the Fractured Rock Aquifer. 

A number of hydrogeological assessments over the last two decades have provided extensive insight into the characteristics of the water resource in the Willunga Basin, but have also identified a number of key data and knowledge gaps. These include issues around groundwater recharge, surface water - groundwater interactions, seawater intrusion, determination of acceptable extraction limits, impacts of future land use change and irrigation with recycled wastewater. 

Extra information and reports

Willunga MV Salinity Report (December 2012) (PDF 6MB)

Willunga Research Update (October 2012)

Publications

Willunga

  1. Batlle-Aguilar J. and Cook P.G. (2012) Transient infiltration from ephemeral streams: A field experiment at the reach scale. Water Resources Research, 48, W11518, doi:10.1029/2012WR012009.
  2. Short M., Cook P.G., Lamontagne S. and Cranswick R. (2014) Characterising the distribution of near-shore submarine groundwater discharge along a coastline using 222Rn and electrical conductivity. Australian Journal of Earth Sciences, 61(2): 319-331.
  3. Banks E., Shanafield M. and Cook P.G. (2014) Induced temperature gradients to examine groundwater flowpaths in open boreholes. Ground Water, 52(6):943-951.
  4. Irvine DJ, Cartwright I, Post VEA, Simmons CT and Banks EW ((2016) Uncertainties in vertical groundwater fluxes from 1-D steady state heat transport analyses caused by heterogeneity, multidimensional flow, and climate change. Water Resources Research, 52, doi:10.1002/2015WR017702.
  5. Irvine DJ, Kurylyk B, Cartwright I, Bonham M, Post VEA, Banks EW and Simmons CT (2017) Groundwater flow estimation using temperature-depth profiles in a complex environment and a changing climate. Science of the Total Environment, 574: 272-281.
  6. Batlle-Aguilar J, Xie Y and Cook PG (2015) Importance of stream infiltration data for modelling surface water – groundwater interaction. Journal of Hydrology, 528:683-693.
  7. El Sawah S, Mitchell M, Guillaume JHA (2011) Using participatory rapid appraisal and DPSIR approaches for participatory modelling: a case study in groundwater management in South Australia. In: 19th International Congress on Modelling and Simulation MODSIM2011, Perth, Australia, 12–16 December 2011.
  8. Guillaume, J.H.A, M. E. Qureshi and A. J. Jakeman (2012) A structured analysis of uncertainty surrounding modeled impacts of groundwater extraction rules, Hydrogeology Journal, 20(5):915-932. DOI: 10.1007/s10040-012-0864-0.
  9. Guillaume JHA, El Sawah S (2014) Fostering assumption-based stress-test thinking in managing groundwater systems: learning to avoid failures due to basic dynamics. Hydrogeology Journal. DOI:10.1007/s10040-014-1153-x