Chalk Hill Road Bridge Replacement Project

The Chalk Hill Road Bridge Replacement Project, managed by Sonoma County in Healdsburg, California, involves the removal of an existing one-lane substandard bridge and the construction of a modern two-lane replacement on an alternate alignment. The new structure will feature a single-span concrete box girder supported by reinforced concrete abutments, providing two 11-foot lanes and two 4-foot shoulders for a total roadway width of 30 feet. To minimize the impact on farmland and reduce embankment fill, retaining structures will be installed along the north and south approach roadways. The project also includes the implementation of scour countermeasures to stabilize the south creek bank and protect the new bridge infrastructure. This presolicitation effort focuses on improving safety and seismic resilience while addressing environmental impacts related to water quality, wetlands, and biological resources. While the project aims to modernize the crossing, the removal of the historic bridge is noted as a significant and unavoidable impact. The project has undergone environmental review, including a Draft Environmental Impact Report with a public review period from September 22, 2026, to November 9, 2026. Coordination is being managed by Senior Engineer Samuel Baumgardner-Kranz and Environmental Planner Liv Niederer to ensure compliance with state clearinghouse requirements and mitigation measures for air quality and cultural resources.