Located around 40 kilometres south of Adelaide, the McLaren Vale is a premium wine-producing region with over 7,300 hectares of vineyards. It is home to more than 200 producers, including 80 cellar doors. Historically, local groundwater and surface water resources were relied upon for irrigation, commercial and industrial uses.
Since the mid-1990s there have been gradual declines in groundwater water levels in most aquifers in the region. This corresponded with a period of below average rainfall.
Increased demand from an expanding viticulture sector, coupled with the pressures of a changing climate made it apparent that the groundwater water resources in the region would not be sufficient to service the projected future demand.
In response to this irrigation shortfall, a climate-independent source of water has been developed. Municipal wastewater is now treated and then piped from SA Water’s Christies Beach Wastewater Treatment Plant to the McLaren Vale by the Willunga Basin Water Company. This water supply scheme was commissioned in 1999 and the use of reclaimed water has continued to increase over time.
Today, the Willunga Basin Water Company distributes more than 6000 megalitres a year of recycled water, or about two thirds of the local wastewater treatment plant’s annual production, throughout McLaren Vale. The recycled water is pumped through a 150-kilometre network of pipes delivering treated wastewater to more than 240 irrigation businesses.
Investigations are currently underway to scope the potential expansion of the treated wastewater water supply scheme, with a view to eventually fully utilising the wastewater treatment plant’s effluent and further reducing ocean discharge.
About 6000 megalitres of groundwater is extracted from aquifers in the region. The sustainability of this groundwater use is managed through a water allocation plan. A water allocation plan is used to manage risks to water resources and articulate how water resources are shared, based on the best available science and community priorities.
A changing climate and rising irrigation demand were placing increased pressure on local groundwater, resulting in reduced availability and increased salinity. The ability to access an alternative source of water has taken pressure off local groundwater resources and enabled irrigated areas to expand. It has also reduced the amount of treated wastewater released to the sea.
Willunga Basin Water Company’s Craig Heidenreich said the recycled water scheme is a win-win for local growers and the environment.
“Recycled wastewater no longer ends up in the ocean damaging marine life, and helps ease the pressure on the local groundwater system,” he said.
“Irrigators across the region can continue to grow with the confidence that water resources are more secure.”
Jock Harvey from McLaren Vale Community Sustainability Company reiterated the dual economic and environmental benefits of the scheme.
“Increasing the volume of water available for irrigation has enabled an expansion of vineyards to meet current demand for premium grapes, thus setting the platform for economic development and jobs growth,” he said.
“The high proportion of recycled water use reinforces McLaren Vale’s credentials as one of Australia’s most sustainable wine growing regions.”