Vineyard acreage in Sonoma County, adjacent to the Napa Valley, has increased 30 to 40 percent during the past decade and the county estimates the businesses generate about $2 billion annually.
But the growth has run up against federal protections for coho salmon, an endangered species that once filled streams and rivers along California's central and northern coasts.
When hibernating vines are coming to life in the spring, temperatures can still drop below freezing overnight and destroy young grapes. During those frigid nights, growers spray river water onto the vines, encasing them in a protective frozen shell.
Farmers say one bad night when temperatures quickly drop 5 to 10 degrees below freezing could wipe out huge percentages of their crop.
"Down here in the bottom, if we don't have the water, it's not going to get it done," said vineyard manager Paul Foppiano, standing in a low-lying field of pinot noir vines near the Russian River. Sprinklers hovered over the gnarled vines in a part of his family's 140 acres, which have been producing wine in Sonoma County since 1896.
"The problem with frost is one year you might have to run 15 to 20 nights like we did a couple of years ago," he said. "Last year we only ran three or four nights so you're not using a whole lot (of water)."
Foppiano is not against the state managing river water use to help protect fish, but believes accurate accounting of use by other county growers is needed before any regulatory decisions are made.
"If the state is willing to work with us, we're willing to work with anybody," he said. "But there's got to be some answer to it other than to completely cut us off. It's going to be a problem."
At issue is the continued existence of the hook-mouthed coho salmon and the threatened steelhead trout that spawn in coastal streams and rivers - a habitat that stretches from Alaska to central California. While coho still thrive in Alaska, their once plentiful stocks in California and Oregon are under threat, federal fisheries managers say.
Under the state's proposed regulation, any pumping would be illegal unless approved by the State Water Board's management program. The new rule could be in effect by 2011.
State water regulators say using river water for frost protection is currently legal, but they are seeking a middle ground that will protect fish and grapes while ensuring some oversight.
"The goal is not to shut (pumping) down, but to make sure it's done in a responsible manner with an eye to making sure the resources are protected," said Vicky Whitney, deputy director for the State Water Board.
In 2008 and 2009, both drought years, vineyard pumping resulted in the deaths of hundreds of coho and steelhead as creek levels dropped, stranding the fish. The kills spurred outrage from environmentalists and concern from federal fisheries managers.
State water officials and federal regulators said it is likely many more fish were killed in undocumented incidents, underscoring the need for quick action. Growers have challenged that notion.
"I question the validity of their assertions of there being several incidents," said Lex McCorvey, executive director of the Sonoma County Farm Bureau, an advocate for the county's wine industry. "(Regulators) have a responsibility to step forward with that information; that way the problems can get fixed. In 2008, there were two incidents, both have been fixed so they won't happen again."
Federal studies show pumping during cold snaps, especially in recent dry years when river levels are low, dramatically affects the river and its tributaries. A study presented by NMFS found pumping for frost protection in 2004 and 2005 resulted in a 97 percent reduction in surface flow of one of the Russian River's key tributaries, Maacama Creek, and the water diversion's effects were seen throughout the watershed.
In April, after documented fish kills, federal fishery biologists at NMFS urged the State Water Board to take control of vineyard pumping. The water board gave the growers six months to come up with their own management plan, but after seeing it, decided to draft their own regulations.
"The agriculture industry is not necessarily wanting to self regulate; we want to self-monitor and educate growers so they're using either no water out of the Russian River or (conservation techniques)," McCorvey said.
Meanwhile, no regulation governs pumping from the Russian River this year.
"It is problematic for us to not have regulatory coverage, because we view the threat of frost protection activities as widespread and significant," said David Hines, a federal fishery biologist and water rights specialist for NMFS.
Grape growers say an entire year's crop could be wiped out if temperatures drop below freezing and they're unable to spray. Environmentalists say the regulations might be too little too late for the area's coho.
"The state board started looking at frost pumping issues in 1997. They've had over a decade to evaluate this issue," said Jeff Miller of the Center for Biological Diversity, one of the environmental groups that filed an intent to sue in an effort to spur action.
"We can't have more fish kills, that can't happen," Miller said. "If there are further fish kills this spring, we'll probably go to court."