Sonoma County supervisors Tuesday approved a design contract to replace a historic steel-truss bridge near Sonoma over objections of preservationists who called the action premature.
Watmaugh Bridge was built in 1929 to span Sonoma Creek and connect what is today Arnold Drive with Highway 12 leading into Sonoma.
County officials say the bridge is at risk of collapse during an earthquake or major flood because of erosion around the piers that support it. The span has the second-lowest rating for structural safety of any in Sonoma County, according to Caltrans data.
"If I can't, and this county can't, do something about the safety about that bridge ASAP, then I think the responsibility we are experiencing is overwhelming," Sonoma Valley Supervisor Valerie Brown said.
Supervisors voted unanimously to award the $500,000 design contract to Moffatt and Nichol, a global engineering firm based in Long Beach. The firm will study other alternatives to replacing the span, including a retrofit or building a parallel bridge downstream.
County transit planners prefer the option of replacing the bridge with one that is 32 feet wide -- 10 feet wider than the current span. They said Caltrans has agreed to restore and replace the bridge's steel trusses, which the county considers to be the bridge's defining historic trait.
But Supervisor David Rabbitt expressed reservations about that plan, saying restored trusses might not fit the bridge's new design, add to costs and "be ugly."
Winemaker Jim Bundschu, one of about a dozen preservationists and neighbors to address the board Tuesday, said a new span would detract from Sonoma Valley's "ambiance."
"It's the last historical bridge in Sonoma Valley that hasn't been bastardized by being modernized," he said.
Several speakers urged supervisors to delay awarding the contract until they had more information about the bridge's condition -- which they say is not as serious as what county staff has made it out to be -- and alternatives to replacing it.