Opting for safety over history, and saving millions in the process, Sonoma County supervisors voted Tuesday to replace the 73-year-old Watmaugh Bridge. A $500,000 design contract, the initial outlay in what could be a $5 million project, was awarded to the Long Beach firm Moffatt & Nichol.
A county report stated that the bridge foundations have been significantly eroded by Sonoma Creek and that the span has the potential to collapse without warning.
“The bridge is vulnerable, “Sonoma Valley Supervisor Valerie Brown said. “A major flood or earthquake would take that bridge out. A retrofit is not a long-term solution.”
The current bridge lacks bike lanes, and its narrow width and bad sight lines are hazardous.
The move to replace the steel-truss structure comes after a prolonged campaign to preserve it as historically significant.
The county Landmarks Commission recommended last week to spare the bridge. It was designated a county historic landmark in 1981. In 1998, the structure was one of 12 spans included in the county’s historic bridges district. Despite the local recognition, the 1929 bridge never qualified for national registration, according to Caltrans and independent consultants.
To retain some of the historical character, the bridge’s distinctive truss elements will be incorporated into the design of the new bridge.
While the county would have been responsible for a retrofit, Caltrans will pay for the new bridge. “Replacement is the only option we have money for,” Brown said.