YOUNTVILLE, Calif. -- California's drought has farmers worried about protecting Napa Valley's reputation for world-class wines.
It's 75 degrees and cloudless outside, and the conference hall in downtown Yountville -- an enclave of upscale inns, restaurants and tasting rooms -- is filled with more than 100 grape growers, mostly gray-haired, wearing plaid shirts and jeans.
"I've never had sunny weather make me feel so gloomy," said Jon Ruel, director of viticulture and winemaking at Trefethen Family Vineyards and president of Napa Valley Grapegrowers, which includes more than 670 growers, vineyards and associated businesses.
Grape farmers gathered here last week to discuss how to protect their fields from record-low rainfall. Options are limited in the Napa Valley, where farms get all of their water from rain that fills rivers and reservoirs, typically 30 inches per year. This year, grape growers are praying for 8 inches. They've gotten no more than 3.5 inches since the rainy season began in October.
Growers are anxious and looking for advice. Wine grape production is Napa County's economic engine, producing $657 million in gross revenue in 2012, according to state statistics. And while about 15 percent of wine sold in the United States is from Napa County, it accounts for 31 percent of total retail value, or $10.1 billion, according to a 2012 industry study.
"I have zero water," said Ashley Bennett, associate vineyard manager for Cain Vineyard and Winery in St. Helena, which specializes in cabernet. "If you had to use all your water last year, then you have no water this year." Her vines are also suffering from Pierce's disease, she said, a bacterial infection spread by insects that dries out leaves and fruit.
Most aren't as badly off as Bennett, who acknowledges that her situation is an extreme. Bennett's vineyard is on a hillside, which doesn't have groundwater wells and relies only on reservoirs that fill with rainwater. She has two ponds that hold about 32 acre-feet of water total; both are dry.
Most areas along the Napa Valley floor have relatively stable supplies of groundwater, so they're not in danger of going totally dry. And farmers in the valley are taking pains to make that point to regulators. Napa County began studying groundwater levels in 2009. The county is now preparing to build a pipeline to bring recycled water to the Coombsville area, which its survey found was in decline, in contrast to most other areas that had good data.
Peter McCrea, proprietor of Stony Hill Vineyard in St. Helena, is chairman of the county's Groundwater Resources Advisory Committee, which is readying recommendations on how to encourage voluntary groundwater monitoring and conservation. He said he expected his own output from his hillside farm to drop about 50 percent from last year's yield of 2 tons of grapes per acre.
"If I'm an optimist, I'd say it'd be about half of what last year was," he said. But he doesn't expect quality to decline. During the dry years of 2006-07, he said, quality was actually improved.
"The grapes are more intense," he said. "You don't get as many grapes, but the ones you do get tend to have more intense fruit."
Adaptation to a 'new reality'
At last week's meeting, experts cautioned against trying to grow too many grapes with not enough water.
"The most challenging thing, because of where we are in the world, is we can't get away with sacrificing quality," said Mike Wolf of Michael Wolf Vineyard Services, which helps operate dozens of farms in the valley. "We just can't go down that road."
Farmers advised their colleagues to pare back their plants according to the amount of water they have. Cutting back leaf canopies reduces the amount of energy that leaves can send to grapes, which prevents the vines from growing more shoots. And using slow-release fertilizers can prevent early growth spurts.
"Focus on a smaller vine if you can accept kind of a reduced crop," Wolf said.
Farmers can also adjust their watering practices. "If you have the choice to do drip irrigation, it'd be much more efficient than overhead," said Amy Warnock, viticulturist at Orin Swift Cellars. But drip irrigation is also flawed, as it deposits water onto only a small percentage of the soil, Garrett Buckland, a partner at Premiere Viticultural Services, pointed out.
Dry farming, which involves carefully managing rainfall, soil and crop timing, can work, but it's not suited to large, densely planted vineyards, Wolf said.
"We have to get smarter about how we water and when we water," Buckland said. Instruments like soil moisture probes; dendrometers, which measure plant growth; and porometers, which measure leaves' CO2 and water vapor conductivity, can help farmers make watering decisions, he said.
As well, Buckland said, farmers in highly visible areas should consider the optics of watering vines with overhead sprinklers during a drought, even if they have adequate supplies. During the daytime, as tourists pass by, "maybe consider turning that off," he said.
They can also take drought into their decisions when planting new vines.
"Maybe we can't grow syrah in Calistoga because it's so thirsty," Wolf said. "If this does in fact become the new reality ... you're making a nominally 25- or 30-year commitment to something that you may not be able to support."
Farmers with well water are deciding whether to start irrigating now to moisten the soil or wait until mid-March, when buds will start to blossom.
There's still hope that the winter will bring enough rain, but long-range forecasts through April are for more dry weather. The high-pressure zone over Northern California, a result of the polar jet stream, has persisted since March 2013.
"Seeing 10 months of this pattern is really unheard of," Buckland said. "We may not be able to break this pattern before winter is over."
Worst could be yet to come
Growers are also worried about next year's supplies. As a perennial plant, the grapevine takes two years to bear fruit, so buds that emerge this year won't ripen until next year. A dry year this year could hamstring bud development, said Mark Matthews, a viticulture professor at the University of California, Davis.
"What we really haven't seen that could happen is, if it's dry enough, grapevines actually become damaged and start to die, so you don't get the buds you need for the 2015 season," he said. "That potentially could become devastating, and it's not like when you're growing corn or something when you can just plant again next year. It's a 30-year commitment."
"This is becoming more frequent, whether we like it or not," said Buckland.
The grape growers' association provided farmers at the meeting with information about crop insurance. For basic catastrophic coverage, which pays out if losses exceed 50 percent of historical yield, the U.S. Department of Agriculture pays the entire premium. The payment is set at 55 percent of established market prices. For fuller coverage, growers can choose to insure themselves up to 85 percent of their historic yield.
Outside the community center, grower Mike Applegate discussed insurance with his agent. If his production is below 25 percent of normal, his insurance kicks in, he said. He said it pays out roughly every five years. Farmers have until Jan. 31 to sign up; they'll know whether it was worth it by the end of the year, when they finish harvesting their crops.
"There's an inch of rain out there," Applegate said. "Jump on it, dude."
Want to read more stories like this?
E&E is the leading source for comprehensive, daily coverage of environmental and energy politics and policy.
Click here to start a free trial to E&E -- the best way to track policy and markets.