LIVERMORE -- With an early harvest just around the corner, Wente Vineyards' Kevin Zollinger is optimistic one of the state's worst droughts in recorded history won't leave the winemaker's precious grapes high and dry.
But there's still cause for concern. Zollinger, an executive with the Livermore Valley's largest vineyard, anticipates a lighter crop yield and smaller fruit than in previous years. And while he's worried about getting enough water for the next growing season, more alarming is the effect of lower-quality water -- caused by a lack of fresh rain to filter minerals from the San Joaquin Delta -- on the sensitive plants.
"The drought is impacting everybody," Zollinger said. "Everybody's cutting back. Are our vines more stressed this year? Yeah, probably, because you don't have the charge in the soil that you normally have."
In the Livermore Valley, where wine is nearly as precious to the economy as water is to sustaining life, winemakers are striking a delicate balance between conserving enough to meet their mandatory 25 percent reductions, and irrigating enough to keep their cash crops healthy.
Like most Tri-Valley residents have had to do with their lawns or gardens, Wente has been forced to cut back on watering its nearly 2,000 acres of grapevines by one-quarter. To hit the mark, the winery drip irrigates six days a week instead of every day, and uses less water pressure.
"We've held back as much as we can without creating damaging stress on the vine," Zollinger said. "It has had an impact, but we're hoping we can still produce a healthy crop."
Winemakers began preparing for the restrictions early this year by working with the Zone 7 Water Agency -- the Tri-Valley's only large water supplier -- to determine how water could best be conserved and shared, according to Livermore Winegrowers Association Executive Director Chris Chandler.
There are 50 wineries and 30-plus vineyards within the Livermore Valley American Viticultural Area. Chandler said the impacts have varied from vineyard to vineyard, based on differences in microclimates, soils and topography.
"The majority of our growers already use sustainable winegrowing practices to conserve water," Chandler said. "However, I think the two best words to describe how local winegrowers are handling the drought are monitor and manage."
So far, the agency's consumers who draw their water directly from the South Bay Aqueduct -- mostly vintners -- are using 29 percent less water as of the end of July than at the same point a year ago, said Carol Mahoney, the water district's planning manager.
"The valley overall has responded," Mahoney said. "If we can stay the course, we're going to make it."
At Concannon Vineyard, the Livermore area's second-largest winemaker, fourth-generation vintner John Concannon has reduced his crop to reach his conservation goals. For the moment, he said, his winery is on stable footing.
"The harvest will most likely be lower, but the quality will be high for 2014," Concannon said. "We've only farmed as much as we could water."
Even if this season produces less fruit, Concannon said his inventory won't suffer too much, because the past two harvests were exceptional. Consumers also shouldn't see any changes in the wine's cost or quality.
"This will be a good year, but next year is a different story," Concannon said. "We really need that El Niño year they say is coming. We just need to conserve and adjust our farming methods."
Most vineyards already employ drip irrigation because it targets the roots and reduces evaporation. Helping conservation efforts is the fact that many winemakers will be harvesting earlier than normal this year because of the hotter summer temperatures.
Winemakers also typically withhold water the grapes crave to limit growth and improve flavor and color, said Janet Caprile, farm adviser for UC Cooperative Extension in Pleasant Hill. But excessive underwatering could push some vines over the edge.
"We're already cutting back, so the plants are already a bit stressed," Caprile said. "With these additional cutbacks, we may be stressing the grapes beyond the quality you'd want. We'd expect to have smaller crops and smaller berries."
Despite the concerns, the wine industry isn't worried about a lack of grapes. Coming off back-to-back record harvests, any drops in production should be absorbed by existing inventories, according to Wine Institute spokeswoman Gladys Horiuchi. Most wineries, she said, should be able to withstand several years of drought without substantial impacts.
"Apparently, even though everyone is being really careful, the bunch counts are normal," Horiuchi said. "They're talking about a fairly average yield."
"There's a lot of wine in the pipeline," she added. "I think things are OK."
But Nat DiBuduo, president and CEO of Allied Grape Growers, a statewide marketing co-op, dreads the drought's cumulative effect. Summer is when the vines' buds determine next year's crop, and if the plants were stressed too much this year, he said, 2015 could be significantly worse.
"We could have a major disaster next year if we don't get any water," he said. "It disturbs me to think about. You might see vines coming out of the ground."
Contact Jeremy Thomas at 925-847-2184. Follow him at Twitter.com/jet_bang.
Total number of wineries: 50
Total number of vineyards: 30-plus
Total vineyard acreage: Approximately 4,000 acres (2,800 under Conservation Easement with Tri-Valley Conservancy)
Overall acreage of Livermore Valley American Viticultural Area: 259,000
First vines planted: 1840, by Robert Livermore
First wineries founded: 1883, by C. H. Wente and James Concannon
Source: Livermore Valley American Viticultural Area (AVA) Facts and Figures