Bridges on the Sonoma County road system are maintained by the Roads Division of the Sonoma County Department of Transportation & Public Works (TPW). TPW currently maintains 328 bridges, which serve over 800,000 trips per day on average.

Bridge Inspections

In California, all designated bridge structures are inspected by Caltrans, the state transportation agency, on a two-year cycle. A bridge inspection examines the structural integrity of each bridge, and is coupled with ongoing staff inspections to form the basis for the County’s bridge program.

Types of Work

Bridge Scour

Stabilization of areas where material is eroding away from the bridge foundation; or, removal of sediment such as sand and rocks from around abutments and piers.


Removal and replacement of damaged concrete, as well as application of surface treatments such as methacrylate resin.

Seismic retrofits

Modifications or enhancements to the existing structure in order to reduce susceptibility to earthquake damage.


Complete removal of the entire bridge structure; construction of a new bridge.

    Past Bridge Projects

    Porter Creek Bridge Replacement Project (2013)

    Complete reconstruction of the Porter Creek Road bridge over Porter Creek.

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    Annapolis Road Bridge Seismic Retrofit (2011)

    Construction of earthquake upgrades on the Annapolis Road Bridge over the Wheatfield Fork of the Gualala River.

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    Roadway & Bridge Surface Preservation Program (2010)

    This project included basic maintenance measures on twenty (20) different bridges. Work done included cleaning expansion joints and replacing joint seals, and cleaning and retreating bridge decks, as well as repairing damaged concrete.

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    Crocker Road Over Russian River Bridge (2006)

    Construction of earthquake upgrades to the Crocker Road bridge over the Russian River.

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    River Road Viaduct Construction (2006)

    Construction of a 6.0-meter-wide by 46.748-meter-long viaduct bridge on River Road along the Russian River, outside of Guerneville.

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    Korbel Crossing (2006)

    Construction of a pile foundation for the Korbel Summer Crossing (Oddfellows Park Road) over the Russian River.

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    Riverside Drive Bridge (2005)

    Reconstruction of the Riverside Drive bridge over the Sonoma Creek, just outside the City of Sonoma.

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    Contact Information

    Business Hours
    Monday – Friday
    8:00 AM – 5:00 PM
    Contact us by Phone
    Office Location
    La Plaza B
    2300 County Center Drive
    Suite B 100
    Santa Rosa, CA 95403
    38.462023, -122.725381

    Caltrans Bridges

    Structure Maintenance & Investigations

    California Department of Transportation (Caltrans)


    Maintaining the safety and integrity of over 24,000 bridges across California.