River Road Bridge Replacement over Gill Creek

Location: 22891 River Rd, Geyserville (Lat/Lon: 38.735432, -122.916093)

Sonoma County is currently working towards replacing the two-lane bridge over Gill Creek, on River Road, Geyserville. The bridge requires replacement due to scour deficiencies and seismic deficiencies.

The proposed new bridge will be a single span (no piers in the stream), precast concrete girder bridge, consisting of two 11 ft lanes and 2 ft shoulders. The new bridge will be constructed along a similar alignment to the existing bridge. The existing bridge will be removed during construction, with a temporary crossing installed downstream of the existing bridge to maintain traffic flow. The substructure shall consist of seat type abutments on footings with Cast-in-Drilled-Hole (CIDH) piles to minimize construction noise. Construction will be performed over a single season.

Project Goals:

• Replace existing bridge with a bridge that meets modern design and construction standards.
• Replace the existing bridge, with a new bridge that is wide enough to eliminate the scour issues.
• Remove the existing weir structure and enhance the stream habitat.
• Improve safety and access for drivers, pedestrians, cyclists, and emergency services

Project Status:

The project completed NEPA and CEQA in 2022.  The County has secured environmental permits.  Right of way acquisition process is underway.  The bridge design is currently at the 65% level.

Estimated Target Dates (subject to change):

• NEPA Clearance spring 2022 (complete)
• CEQA Clearance fall 2022 (complete)
• Begin permitting September 2022 (complete)
• Complete right of way acquisition November 2023
• Begin Utility relocation December 2023
• Begin Construction June 2025

Please direct any questions to Chet Jamgochian at chet.jamgochian@sonoma-county.org.