Less than a mile from the contested Green Bridge, the county has identified another failing bridge for imminent replacement, on Levee Road.
The Sir Francis Drake Boulevard Bridge is a three-span, concrete slab structure that crosses Lagunitas and Olema Creeks and dates back to 1930. The county says it needs to replace it to address diminished load carrying capacity, erosion on one of the piers and its ability to withstand the force of an earthquake.
According to a recent memo, the site is adjacent to the San Andreas fault and the bridge was not designed to withstand the “high seismic forces and liquefaction that are expected to occur during an earthquake.”
It is one of six priority bridges for which the county won federal funds to rehabilitate in 2013 through the Highway Bridge Program, which Caltrans administers through its local assistance program. The federal monies for the project, which will be the last of the six to kick off, total $2.1 million. (The county plans to supply the remaining 12 percent of the estimated cost.)
Eric Miller, principal civil engineer for the county, said that although the proposed start date for the project was originally next spring, it will likely be later—possibly after construction is completed on the Green Bridge, a project slated to begin in the spring of 2020. He added that the county will ensure the two do not overlap.
Though he emphasized the importance of the public process and said no designs have yet been drawn, Mr. Miller did say the bridge was in a condition that necessitated a replacement rather than a retrofit—which many requested for the Green Bridge. (Of the five other priority bridges, just one, in Marinwood, was a retrofit.)
The project may involve closing Levee Road and rerouting traffic along Bear Valley Road. Alternatively, the project could be constructed in stages while maintaining a single lane of traffic through the project site, although in that scenario, the timeline would double.
The county, which is collaborating with Caltrans and two private contractors, has already begun site surveys and environmental studies to comply with both the national and California environmental policy acts. Olema Creek is a valued riparian corridor, and there are several endangered and threatened wildlife species found within or near the project area, including salmonids.
Residents who live near the site may be asked to allow surveyors and environmental specialists to enter their properties to complete their studies. A community meeting on the project will be held next Thursday, May 31 from 6:30 to 8 p.m. at the Dance Palace Community Center.
For more information, check out the “Sir Francis Drake Blvd Bridge Replacement Project” on the county’s website, or contact Eric Miller at [email protected] or (415) 473.4399.