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SR 520 - Project Permits

As part of the environmental compliance process for the I-5 to Medina project, WSDOT applied for numerous federal, state, and local permits. All required permits were issued by early 2012, allowing WSDOT to proceed with replacement of the vulnerable SR 520 floating bridge and development of natural resource mitigation sites.

View an interactive map of our natural resource and park mitigation sites.

What permits were issued for the SR 520, I-5 to Medina project?

Following several years of coordination, in March 2012 WSDOT received the final permit necessary to begin construction on the SR 520 floating bridge. Local, state, and federal agencies issued the following permits and authorizations:

City of Seattle shoreline permit 


1. Floating Bridge and West Connection Bridge
2. Montlake Bascule Bridge
3. Portage Bay Bridge
4. Taylor Creek Mitigation Site
5. West Approach Bridge

Issued by city of Seattle on Jan. 17, 2012

Approved by Department of Ecology on Feb. 17, 2012

6. Magnuson Park Mitigation
7. Union Bay Natural Area Mitigation Site
8. WSDOT Peninsula Mitigation Site
9. Seward Park Mitigation Site

Issued by city of Seattle on Jan. 17, 2012

Approved by Department of Ecology on Feb. 17, 2012

City of Medina shoreline permit 


10. Floating Bridge and East Approach Conditional Use Permit
11. Floating Bridge and East Approach Shoreline Substantial Development Permit
12. Bridge Maintenance Facility Conditional Use Permit
13. Bridge Maintenance Facility Shoreline Substantial Development Permit

Issued by city of Medina on Feb. 1, 2012

Approved by Department of Ecology on Feb. 17, 2012

State and federal permits covering I-5 to Medina


14. Department of Ecology - Clean Water Act Section 401 Water Quality Certification

Issued by Department of Ecology on Feb. 15, 2012

15. Department of Ecology - Coastal Zone Management Program Consistency Determination

Issued by Department of Ecology on Feb. 21, 2012

16. U.S. Coast Guard - General Bridge Permit

Issued by U.S. Coast Guard on March 9, 2012

17. Washington Department of Fish and Wildlife (WDFW) - Hydraulic Project Approval

Issued by WDFW on March 9, 2012

18. U.S. Army Corps of Engineers - Sections 10 and 404 permits

Issued by U.S. Army Corps of Engineers on March 23, 2012

Were the permit applications based on the selected alternative design?

Yes, the permit applications were based on the design of the selected alternative, which WSDOT evaluated in the final environmental impact statement as the "preferred alternative." This alternative was selected in the record of decision, which was issued by the Federal Highway Administration in August 2011.

How were permitting agencies involved in the project?

WSDOT worked closely with local, state and federal agencies throughout the planning and design process on issues such wetland and aquatic mitigation, in-water construction, stormwater, and fish passage.

Agency staff provided valuable input and feedback during the design process. Their feedback resulted in fewer impacts to natural resources, and helped the project team identify appropriate mitigation for impacts that could not be avoided or minimized.