I’m standing with Joe Uhr, Director of Winemaking at Gundlach Bundschu winery in Sonoma, California, looking out over an idyllic lake, sparkling in the winter sunshine, vineyards in the distance. Uhr points out a turtle sunning itself by the water below us. Yet this lake is in fact an artificial pond, part of Gundlach’s sophisticated system for recycling winery wastewater.
Here as in many wine regions, water is becoming a significant issue. Even if they don’t use irrigation, producers use water at every stage of winemaking, above all in cleaning everything from tanks to pumps to floors. In South Africa, for example, Eben Olderwagen, Environmental Manager at Vergelegen (pictured above), tells me they use around 85,000 litres a day in summer, not including irrigation.
Getting the measure of water consumption is key
Gundlach Bundschu, certified both organic and for regenerative agriculture, is tackling the issue as part of its sustainability programme. ‘Every pump we have has flow meters on it,’ says Uhr. ‘It’s been a long time coming in the wine industry. Water is becoming more and more of an issue in California.’
California wineries are now legally required to clean wastewater before releasing it.
California wineries are now legally required to clean wastewater before releasing it. Gundlach uses a dual pond system – the one I could see was the larger of the two, used for storing recycled water as well as collected rainwater. In the smaller pond, wastewater is piped from the winery. The winery adds bacteria that clean up the water, fed with oxygen by aerators powered by floating solar panels. After treatment, they pump clean water up to the big pond, from where it’s used to irrigate vines.
A few hundred miles to the south in Paso Robles, Jason Haas of Tablas Creek shows me their alternative wastewater system. Tablas created a wetland area close to the winery with a settling area to get rid of solids such as grape waste, and then a gravel-bedded lake with water plants which the water gradually feeds through. This not only provides habitat for wildlife, but a source of clean, recycled water to irrigate grass for their flock of sheep in the summer.
Capturing storm water is another tactic, especially in places where climate change is bringing drought. In Catalunya, dry recent years mean that parts of the region now have a semi-arid climate. ‘It shows us what the future is bringing,’ says Sara Pérez, chief winemaker at Mas Martinet, in Priorat. ‘Every time the weather is more extreme.’ They use pools to collect rainwater in autumn and winter from roofs and other surfaces.
Wineries can also do a lot to cut the amount of water they use in the first place. Mas Martinet now use steam cleaning at 150°c for barrels, which uses less water and does a better job than washing them down with hoses.
More prosaically, wineries can cut their water use by cleaning off solid matter such as grape skins and tartrate deposits manually, before using water. At Vergelegen, says Olderwagene, even their choice of paint for the winery floors makes a difference to how much water they need to clean off sticky deposits and the like.
Improved technology helps to tailor irrigation to a vine’s needs
Where producers use irrigation – banned in many parts of Europe – that greatly increases their water consumption. However, technology is helping transform growers’ understanding of their vines’ water needs. Warwick Estate, in South Africa, uses data gathered by drone to monitor plants’ vigour and water stress. Similarly at Jackson Family Wines, Craig McAllister, head winemaker at La Crema, contrasts the old approach – ‘it used to be, it’s Monday, let’s irrigate’ – with the soil moisture probes at surface and root level that they use today to guide irrigation.
Meanwhile at Symington’s Estates in the Douro Valley, in Portugal, around 40 per cent of their vineyards are irrigated. Research and Development Manager Fernando Alves explains that precise drip irrigation can reduce the amount of water by up to 40 per cent on what a conventional irrigation system would use. A new system of sensors on vines gathers data in real time, showing which places need water and how much.
>> Read more about how Symington’s are tackling water use with pioneering new technology
Soil structure can play a role in reducing the plants’ need for water
Reducing water inputs is also one argument for techniques that focus on soil health, especially biodynamic and regenerative viticulture. One US study showed that every extra percentage point of organic matter in an acre (0.4 hectares) allows the soil to retain another 20,000 gallons (75,700 litres) of water, because of its effect on soil structure. Similarly, Californian studies on regenerative versus conventional agriculture show that cover crops between vine rows can significantly reduce both the soil surface temperature and the temperature of the leaf canopy, thereby reducing the plants’ need for water.
It's an urgent task. Even if we reduce our carbon emissions, we’ll still be dealing with the effects of climate change for many decades. That will mean several generations of winemakers paying close attention to the amount of water they use.
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