A wealthy financier's embattled proposal to construct a small winery in the hills north of Santa Rosa earned final approval Tuesday in front of the Sonoma County Board of Supervisors.

The 10,000-case winery, proposed by Goldman Sachs partner Henry Cornell, is planned for 40 acres off St. Helena Road, 1.5 miles west of the Napa County line. Cornell owns 215 acres in the area, including vineyards.

Along with two buildings that together total 6,700 feet, his project also calls for 10,200 square-feet of excavated wine caves.

The winery's approval, eight years after it was first proposed at a larger scale, came in a straw vote by supervisors denying an appeal filed by project opponents.

Representatives of a group called New-Old Ways Wholistically Emerging, or NOWWE, and other unaffiliated neighbors and environmental advocates claimed the project would impact water quality and quantity in Mark West Creek, further endanger the waterway's rare salmon and steelhead populations and boost traffic beyond what a curvy county road could handle.

But an environmental review that posed those questions came back with a ruling that the project would have no significant environmental impacts after incorporating more than 80 measures to safeguard wildlife and water, and other resources.

Together the measures added more than a $1 million to the project's cost, said John Holdredge, an attorney for Cornell.

"Our overriding goal has been to set the standard for environmentally sensitive wineries in that area. I think we've done that," Holdredge said.

Supervisors largely agreed, saying the project had gone above and beyond what would have been required of many other uses of the property.

Changes to meet environmental concerns included reducing the initial project from 20,000 cases, maximizing use of rainwater collection for the facility and limiting use of groundwater in the dry season.

"That is due diligence way beyond what we usually see in this chambers," said Supervisor Valerie Brown.

Changes approved two years ago call for appointment-only wine tasting and no special events beyond 10 winemaker dinners with 10 guests per year.

On Brown's recommendation, the board added conditions that would also ban vacation rentals and events on a residential property connected to the site.

Wine industry officials supported the project's approval but cautioned the board not to consider the additional safeguards and limits a precedent for future winery projects.

Nick Frey, executive director of the Sonoma County Winegrape Commission, called the extra conditions "extraordinary steps" that Cornell could afford but which would be "cost prohibitive" to any most other new wineries.

The project opponents said they were disappointed with the ruling. They argued that the environmental review did not take into account the cumulative impact of another winery on Mark West Creek, a watershed they said has been hammered by vineyard and housing development.

Stephan Volker, an attorney for NOWWE, said the group was considering a legal challenge.

"We remain committed to securing enforcement of state and local laws that require protection of the creek and its sensitive species," Volker said.

Cornell, who did not attend the hearing, lives in New York.

The board is set to finalize its straw vote at the Dec. 11 meeting.

You can reach Staff Writer Brett Wilkison at 521-5295 or brett.wilkison@pressdemocrat.com.