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One of Australia’s largest and most successful recycled water vineyard irrigation schemes is being expanded in South Australia.

The $7.3 million expansion includes the construction of a 600-megalitre dam south of Adelaide to store water from the Christies Beach Waste Water treatment plant before it is pumped out to more than 220 McLaren Valeirrigators.

The dam will enable new plantings and allow the pipeline network to be extended to reach more vineyards.

Deputy Prime Minister Michael McCormack today announced the McLaren Vale Community Sustainability Company would develop the project, $2.5 million of which has been funded under the National Water Infrastructure Development Fund.

He said the project was expected to yield an additional $5.5 million in grape production for McLaren Vale annually, lead to an estimated $33 million yearly increase in wine production and create more than 160 winery jobs.

The McLaren Vale Community Sustainability Company is a not-for-profit community group formed by the McLaren Vale Irrigators Council. It has partnered with the Willunga Basin Water Company, which is contributing $4.8 million to deliver the project.

The annual treated volume of the Christies Beach WWTP is around 10,000 ML. The new dam will allow WBWC to increase its intake to more than 6000ML a year, or about two thirds of the plant’s production with the balance of treated water discharged to Gulf St Vincent. About 6000ML a year is also drawn from groundwater each year to irrigate the region’s 7000 hectares of vineyards

The Willunga Basin scheme has a 120km network of pipes delivering treated wastewater to more than 220 irrigators across more than 2000ha. The long-term goal is to develop more dams and pipe networks to ultimately take all of the Christies Beach wastewater to relieve pressure on the region’s dwindling groundwater supplies and reduce the amount of wastewater flushed out to sea.

Willunga Basin Water Company’s Craig Heidenreich said the project was a win-win for local growers and the environment.

“Recycled waste water no longer ends up in the ocean damaging marine life but 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 across the region are more secure.

“This project further establishes McLaren Vale’s credentials as one of Australia’s most sustainable wine growing regions.”

Construction contracts are expected to be awarded by the end of October with the overall project due to be completed and on-line by June 2020.

The McLaren Vale region 40km south of Adelaide is home to more than 80 wineries. Its dry climate, lack of humidity and proximity to suburban Adelaide has given it a sustainability edge, which it began developing in the 1990s when it became Australia’s first wine region to self-impose water restrictions on its underground resources.

The Willunga Basin Water Scheme was introduced in 1999 when the first recycled water pipeline connected McLaren Vale to recycled wastewater from Christies Beach, about 15km away.

The new dam will be about 330 metres long, 265m wide and 9.3m deep with a proposed water depth of 8.3m.

It will be a ‘turkey’s nest’ dam with the top of the dam banks elevated above the natural ground level and as such there will be no natural runoff into the dam.

The treated water purchased from SA Water is pumped several kilometres from the Christies Beach plant to WBWC’s small 13ML Quarry Road, Seaford Heights. From the Quarry Road site, WBWC distributes the recycled water at pressure to customers in McLaren Vale via an existing network of pipes. Recycled water received at Quarry Road is proposed to be pumped to the nearby new dam for storage in winter, and gravity fed back to the Quarry Road site when it is needed for distribution to customers in summer.

McLaren Vale Community Sustainability Company Director Shaun Allan said although the dam had a 600ML capacity it would likely allow about an additional 800ML to be pumped from Christies Beach each year to keep it topped up as the water was used.

“Once that additional water has been secured it will allow Willunga Basin Water Company to provide more water to existing irrigators and expand their pipe network out into the Blewitt Springs region, which is one area that’s been identified as being not very secure from an irrigation point of view,” he said.

“We need another couple of dams or storage facilities to complete the process but this is a big step towards that.”

“There’s an aspect of this that is insurance to protect growers in very dry years and there’s also an aspect that provides flexibility for more plantings and expanding the WBWC pipe networks into more areas.”

Known for its premium Shiraz and Grenache, McLaren Vale is Australia’s fifth largest wine region by value, producing grapes with an estimated value of $58 million in 2019. It is home to several world-renowned brands including Hardys, Wirra Wirra and d’Arenberg.