King Ridge Road Bridge Replacement Project

Sonoma County Public Infrastructure is undertaking the King Ridge Road Bridge Replacement Project in Cazadero, California, to replace a structurally deficient one-lane bridge crossing Austin Creek. The project involves constructing a new two-lane bridge with shoulders and upgraded barriers on a new alignment upstream of the current structure. To maintain traffic flow, the existing bridge will remain operational until the new bridge and its associated road approaches, retainment walls, and guard rails are completed. The project is scheduled over two construction seasons, with the first season focusing on the new bridge and road realignment and the second season dedicated to the demolition of the existing bridge and its in-channel pier to improve fish passage and hydraulic conditions. The project must adhere to Caltrans Standard Specifications, including the requirement to pass a 100-year flood event with four feet of freeboard. Environmental compliance is managed under the California Environmental Quality Act, with a Mitigated Negative Declaration indicating no significant adverse impacts after mitigation. Key requirements include the implementation of a Storm Water Pollution Prevention Plan and strict adherence to construction windows, specifically restricting in-channel work to between June 15 and October 15 and limiting all construction activities to daytime hours from 7am to 7pm. Necessary authorizations are required from the U.S. Army Corps of Engineers and the North Coast Regional Water Quality Control Board.