TPW Roads

Watmaugh Bridge Public Meeting

Published:  March 13, 2017

Meeting details:

WHEN: 6 pm, Monday, March 20th
WHERE: Gym at Adele Harrison Middle School
1150 Broadway, Sonoma, CA 95476


  • Condition of Watmaugh Bridge
  • Brief History of the Project
  • Approved Design
  • Status Updates
  • Next Steps

What is the proposed project?

The new bridge will be 32 feet wide, consisting of two 11 foot travel lanes and two 5 foot shoulders. To preserve the historical aesthetics of the bridge, the trusses will be removed from the existing structure and placed onto the new bridge, which will be built within the approximate alignment of the existing bridge.

What are the recent highlights?

The engineering design for the bridge is substantially developed, and construction could begin as early as 2019. The National Environmental Protection Act (NEPA) process is close to completion, and includes the recent designation of eligibility for Watmaugh Bridge on the National Register of Historic Places. The California Environmental Quality Act (CEQA) process was completed, including public hearings, and approved by the Sonoma County Board of Supervisors in December of 2012. 

Why must Watmaugh Bridge be replaced?

Watmaugh Bridge is seismically vulnerable and severely structurally deficient. It does not meet modern seismic standards and could be subject to collapse during moderate to severe earthquake. Additionally, the bridge suffers from structural deficiencies, including:

  • Rust in several joints has caused the concrete to crumble away from the underlying steel.
  • Inadequate footings are undermined by high creek flows. Substantial erosion has been noted around the base of the shallow footings.
  • The truss has deteriorated and can no longer support normal loads.

The Sufficiency Rating of the bridge, which is a federal standard, rates the bridge at 4 out of 100.

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

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