Russian River grape growers are hoping to gather enough water-use data from fellow farmers to avoid strict restrictions this spring on stream diversions for frost protection.
Federal officials and environmentalists have called for such regulations to keep adequate water in streams for endangered salmon and steelhead.
Grape growers Wednesday will begin a week of meetings aimed at determining how much of their acreage on three local streams is protected from frost by irrigation, and where that water comes from. The three streams are Mark West, Green Valley and Maacama creeks.
Farm leaders hope the data can show areas where the threat to fish is less than first feared, as well as places where storage ponds or other measures are needed to avoid drying up streams on freezing spring nights.
"Growers can respond if we know what the problem is," said Pete Opatz, a viticulturist overseeing vineyards in Napa and Sonoma counties for Silverado Premium Properties.
The data will be presented later this month to the staff of the state Water Resources Control Board.
The board members held two meetings last year after the National Marine Fisheries Service called for regulating diversions for frost protection. Observers have said the board appears ready to put new rules in place before frost protection begins in March.
Three environmental groups notified the water board in November of their intent to sue the state under the federal Endangered Species Act. The three are the Center for Biological Diversity, Northern California River Watch and Coast Action Group.
Alan Levine, executive director of Coast Action Group, expressed skepticism that the new data could alleviate the need for state regulation.
"I'll believe it when I see it," he said. Moreover, he said, the growers have to persuade federal officials who to date have rejected the idea of allowing growers to regulate themselves.
On freezing nights in spring, many growers spray water over their vineyards to protect the vines from damage. The irrigation water freezes and encapsulates the green buds in ice, keeping the plant tissue safe at a constant 32-degree temperature.
But federal officials said frost protection in 2008 and last year stranded and killed both coho salmon and steelhead, an action forbidden by the Endangered Species Act.
Five grower meetings will take place from Wednesday through Jan.14. While the immediate focus is on the three creeks, the larger goal is to gather similar water usage data of vineyards throughout the Russian River watershed.
"Nowhere in the state has any farm group done this before," Opatz said.
Sonoma County has about 60,000 acres planted in grapes, according to the county agricultural commissioner's office. Not all those acres are protected from frost with water, but the only way to get an accurate accounting is for all growers to take part in the survey, said Nick Frey, president of the Sonoma County Wine Grape Commission.
"The goal is we want everybody to come to these meetings, not just the ones doing frost protection," Frey said.
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