Snohomish County Has Replaced or Rebuilt 56 bridges in the Past 20 Years

Snohomish County bridges and culverts connect approximately 1,600 miles of unincorporated county roads, linking towns, cities and federally protected lands and waterways.

Between 2003 and 2023, Snohomish County has replaced or rebuilt 56 bridges – more than 25 percent of its entire bridge inventory. Details about bridge inspections, repairs and replacement projects are available online in the 2023 Annual Bridge Report.

“As our county continues to grow, it is essential that our infrastructure keeps pace and provides access for residents and responders“, Snohomish County Director of Public Works Kelly Snyder said. “By successfully securing federal funds to cover more than 80 percent of bridge construction costs, we proactively plan for major repair and replacement projects. Our number one priority is to keep bridges safe and open for the public.”

Last year, the county bridge group inspected 107 county bridges and completed eight major bridge repair work orders, including an emergency repair to replace a damaged timber beam on Riley Slough Bridge 52. In addition, county crews inspected 28 city-owned bridges under Interlocal Agreements. Bridge conditions are well-documented and include a sufficiency rating that helps the county understand the condition of the bridge and prioritize which bridges may need routine maintenance, repair or replacement.

In 2006, a flood damaged Index-Galena Rd closing it for nearly two decades. A 180-foot long single span bridge allowed the re-opening in Nov. 2023.

“Our bridge inspection teams are working throughout the year to gather information and prioritize maintenance and repairs,” Snohomish County Public Works Bridge Engineer Tim Tipton said.

Bridges scheduled for replacement are still safe for travel but nearing their end of their service life and require increasing maintenance and repairs. A list of proposed bridge replacement or rehabilitation projects through 2025, include:

• Red Bridge 537 Preventative Maintenance
• Jordan Creek Bridge 214 Replacement
• Snohomish River Bridge 1 Scour Mitigation
• Swamp Creek Bridge 503 Replacement

In 2023, the county bridge inventory grew from 205 to 210. Crews completed construction of Seven Mile Bridge 673 on the reopened section of Index-Galena Rd and built Mann Road Culvert 145 as part of the Mann Rd and Ben Howard Rd Improvements project south of Sultan.

The Stillaguamish Tribe built the 236th St Culvert 680 as part of the 236th St NE Safety Improvements Project north of Arlington, and developers constructed Woods Creek Vista A 681 and Woods Creek Vista B 682 as part of a new housing development east of Monroe. All four culverts have spans greater than 20 feet, which meets the National Bridge Inspection Standard (NBIS). These culverts will be managed as part of the county bridge network.

All county bridges are inspected at least every two years. A small number of bridges are inspected more frequently due to certain deficiencies that require additional monitoring. Bridge inspections are performed in accordance with the National Bridge Inspection Standards (NBIS). Inspection information is shared with the Washington State Department of Transportation (WSDOT) and Federal Highway Administration (FHWA) to determine the eligibility for federal rehabilitation or replacement funds.