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)
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