Sonoma County adopts hillside vineyard restrictions
New rules making it tougher to rip up forested hillsides to plant vineyards won qualified approval from the Sonoma County Board of Supervisor Tuesday.
The stronger erosion prevention measures were unanimously approved by the five supervisors, but most acknowledged that the process was viewed as frustrating and flawed by many involved.
Supervisor Efren Carrillo praised the work of staff and the interest groups, but he said the ordinance was "not perfect by any means."
Environmental groups think it doesn't go far enough, and agriculture and growers groups believe the process was rushed, Carrillo said.
"It seems to me that no one's happy here, on either side," Carrillo said.
The vote was the culmination of four months work by county staff to craft rules aimed a strengthening erosion control measures ahead of immediate proposals for hillside vineyard projects totaling 341 acres.
Grape growers in the county are increasingly eyeing forested hillsides for their vines now that most of the easily developed agricultural land suitable for grapes has been converted to vineyards.
The county's agricultural community expressed displeasure with both the process, which included a four-month moratorium on new vineyard plantings proposing tree removal. and plans to apply the rules to orchards as well as vineyards.
But Agricultural Commissioner Tony Linegar relented on that last point, agreeing to exempt orchards from the new regulations. The evidence showed that modern vineyards, which usually have grasses between the rows of vines, do a better job of preventing erosion than old orchards, he said.
"If your orchard has a certain amount of erosion, your vineyard is going to have less," Linegar said.
Aside from that exemption, the rules passed Tuesday were basically the same as initially proposed last month. They would prohibit tree removal on the steepest of slopes, keep vineyards 50 to 100 feet away from unstable hillsides and require three years of follow-up to ensure the regulations are effective.
Under the Vineyard Erosion and Sediment Control Ordinance, or VESCO, hillside vineyards currently can be planted on slopes up to 50 percent with virtually no prohibition on tree removal. Linegar has said this was an oversight that ignored the key role tree roots play in stabilizing hillsides and the role tree canopies play in reducing erosion and sedimentation.
Under VESCO, a vineyard project is considered "Level 2" if the slopes are over 15 percent for normal soils or 10 percent for highly erodible soils. Projects in such areas that propose removing more than half an acre of trees will be subject to stricter review.
Under the new rules, when soils are unstable, trees can not be removed on grades above 40 percent. For those between 25 and 40 percent, a "slope stability analysis" must be performed by a licensed geologist to ensure it is safe to remove trees.
To ensure property owners don't clear trees before seeking a vineyard permit, Linegar said the county will use satellite photographs to analyze the tree canopy.
"It takes away any incentive for somebody to clear their property prior to applying for a permit to develop a vineyard," Linegar said. "We've leaned a lot from what Napa County has been through."
In addition, vineyards must be set back 50 feet below a grade of 50 percent or more and 100 feet above such a grade.