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This page contains documents involving environmental review and analysis for the individual construction projects that constitute the SR 520 Bridge Replacement and HOV Program.
The SR 520 Program’s project-design documents can be found here.
February 2021 - NEPA/SEPA reevaluation for Portage Bay Bridge and Roanoke Lid Project (pdf 1.3 mb)
February 2021 - Revised Section 4(f) evaluation for Portage Bay Bridge and Roanoke Lid Project (pdf 2.3 mb)
May 2020 - SR 520 Floating Bridge and Landings Project AKART Stormwater Study Final Report (pdf 24 mb)
October 2019 - NEPA/SEPA Environmental Reevaluation: I-5 Design Refinements, Attachment 1 (PDF 402KB); SR 520: I-5/Mercer St to SR 520/Portage Bay I-5 Interchange Improvements (I-5 Express Lanes Connection Project) Noise Discipline Report (pdf 5.5 mb)
September 2018 - NEPA/SEPA environmental reevaluation: Wireless Communications Facility Removal and Relocation (PDF 35MB)
July 2018 - NEPA/SEPA environmental reevaluation: Montlake Market Closure and Demolition (PDF 754KB)
October 2016 - NEPA/SEPA environmental reevaluation: West Approach Bridge South and Montlake lid design refinements (PDF 3MB)
April 2016 - NEPA/SEPA Environmental Re-evaluation: Floating Bridge Demolition (pdf 97 kb)
January 2014 - SR 520 Floating Bridge and Landings Project Sustainability Report (pdf 5.7 mb)
March 2013 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Final Construction Noise and Vibration Report (pdf 6.9 mb)
December 2011 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Final Aquatic Mitigation Report (revised February 2012) (PDF 48MB)
December 2011 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Final Wetland Mitigation Report (revised February 2012)
August 2011 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Geomorphology and Shoreline History of Lake Washington, Union Bay, and Portage Bay Technical Memorandum
August 2011 - Record of Decision (pdf 4.9 mb)
The Federal Highway Administration (FHWA) has signed the Record of Decision, a document that finalizes the NEPA environmental process and allows WSDOT to further design for the I-5 to Medina: Bridge Replacement and HOV Project and obtain construction permits.
The Record of Decision also lists many commitments made by WSDOT and FHWA to surrounding communities before, during and after project construction. These commitments include mitigation for project effects to the environment and neighborhoods as well as implementing traffic-calming measures in the Arboretum and developing a community construction management plan.
Attachments
June 2011 - Final Environmental Impact Statement (FEIS)
The final EIS compares the Preferred Alternative with the design options analyzed in the supplemental draft EIS, further refines previous analyses based on the Preferred Alternative design, and identifies how WSDOT will avoid, minimize and mitigate for project effects. The document also takes into account the latest assumptions about other regional transportation and development projects to place the project within a wider context.
In the final EIS, we respond to comments from agencies, tribes, jurisdictions and the public.
Final EIS - Executive Summary (pdf 6.8 mb)
Cover, Front Matter, and Table of Contents (pdf 2.5 mb)
Chapter 1 - Introduction to the Project (pdf 1.6 mb)
Chapter 2 - Alternatives
Chapter 3 - Construction Activities
Chapter 4 - The Project Area's Environments
Chapter 5 - Project Operation and Permanent Effects
Chapter 6 - Effects During Construction of the Project (pdf 7.5 mb)
Chapter 7 - Cumulative Effects (pdf 2.90mb)
Chapter 8 - Other Consideration (PDF 183KB)
Chapter 9 - Final Section 4(f) Evaluation (PDF 8.6MB)
Chapter 10 - Section 6(f) Summary (pdf 7.1 mb)
Chapter 11 - Public and Agency Comments (pdf 298 kb)
Attachments
Attachment 7 - Discipline Reports
Final Cultural Resources Assessment and Discipline Report
Cultural Resources Attachments
Attachment 3
Attachment 4A
Attachment 4B
Attachment 4C (pdf 2.6 mb)
Description of Alternatives Discipline Report Addendum (pdf 3.9 mb)
Ecosystems Discipline Report Addendum (pdf 8.3 mb)
Energy Discipline Report Addendum (pdf 1.8 mb)
Environmental Justice Discipline Report Addendum (pdf 1.4 mb)
Geology and Soils Discipline Report Addendum (pdf 953 kb)
Hazardous Materials Discipline Report Addendum (pdf 865 kb)
Final Indirect and Cumulative Effects Analysis Discipline Report (pdf 4.5 mb)
Land Use, Economics, and Relocations Discipline Report Addendum (pdf 2.1 mb)
Navigable Waterways Discipline Report Addendum (pdf 768 kb)
Noise Discipline Report Addendum (pdf 13.6 mb)
Recreation Discipline Report Addendum (pdf 3.3 mb)
Social Elements Discipline Report Addendum (pdf 3.4 mb)
Final Transportation Discipline Report
Visual Quality and Aesthetics Discipline Report Addendum
Water Resources Discipline Report Addendum (pdf 3.6 mb)
Attachment 8 - Correspondence
Attachment 9 - Mitigation Plans
Conceptual Aquatic Mitigation Plan
Arboretum Mitigation Plan Final Report (pdf 1.8 mb) December 2010
Section 106 Programmatic Agreement (pdf 2.4 mb)
Community Construction Management Plan Outline (pdf 177 kb)
ABGC Memorandum of Understanding (pdf 1.3 mb)
Attachment 10 - 2010 Supplemental Draft EIS
Attachment 11 - Responses to 2010 SDEIS Comments
Community Organizations
Federal Agencies
Individuals
Local Agencies
State Agencies
June 2011 - Section 106 Technical Report
*Volume 1 of this report contains sensitive cultural resources information that is exempt from public disclosure pursuant to provisions of the Public Records Act (RCW 42.56.300). The Final EIS Cultural Resources Discipline Report contains all information from Volume 1 of the Section 106 Technical Report that is available for the public.
Summary and Introduction (pdf 2.7 mb)
Vol. 2 - Built Environment
Technical Report Vol. 2 - Built Environment Appendices Part 1
Technical Report Vol. 2 - Built Environment Appendices Part 2
April 2011 - Standards and Guidance Referenced in the SR 520, I-5 to Medina Bridge Replacement and HOV Project – Section 106 Programmatic Agreement - Appendix E
Crime prevention through environmental design (pdf 68 kb)
Seattle Parks and Recreation Olmsted Park Furniture Standard (pdf 567 kb)
DAHP recordation standards for structures (pdf 60 kb)
Secretary of the Interior's Standards and Guidelines for the Treatment of Historic Properties (pdf 59 kb)
Context-sensitive solutions in transportation planning (pdf 27 kb)
Seattle Right of Way Manual - City of Seattle standards about street trees (pdf 72 kb)
WSDOT Standards Specifications Manual (pdf 5 mb)
WSDOT Roadside and Site Development - WSDOT revegetation standards (pdf 20 kb)
DAHP guidelines on archeological data collection (pdf 3.5 mb)
City of Seattle requirements concerning noise variances (pdf 111 kb)
WSDOT policy and procedures on consultation about noise walls (pdf 228 kb)
WSDOT Environmental Procedures Manual (pdf 9.9 mb)
WSDOT No idle and fuel conservation policy (pdf 364 kb)
February 2011 - SR 520 I-5 to Medina Project Section 6(f) Environmental Evaluation Frequently Asked Questions (pdf 252 kb)
November 2010 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Environmental Evaluation of Section 6(f) Replacement Sites (pdf 2.5 mb)
April 2010 - SR 520, I-5 to Medina: Bridge Replacement and HOV Project Supplemental Draft Environmental Impact Statement Summary of Comments (pdf 2 mb)
January 2010 - Supplemental draft EIS
What is a supplemental draft environmental impact statement?
The SR 520, I-5 to Medina: Bridge Replacement and HOV Project Supplemental Draft EIS presents information about the project to inform citizens about the potential effects of project choices and to assist decision-makers in considering how the project should proceed. It builds on the work of the 2006 draft EIS by evaluating a new set of 6-Lane Alternative design options.
According to the National Environmental Policy Act and State Environmental Policy Act, an agency must prepare a supplemental draft EIS when:
Why is the supplemental draft EIS important to me?
The supplemental draft EIS presents an important opportunity for the public to formally comment on the I-5 to Medina: Bridge Replacement and HOV Project's effects and have their comments tracked, published and addressed by the project team in the final EIS.
Supplemental draft EIS - Executive Summary (pdf 2.9 mb)
Supplemental draft EIS - Full Document
Cover and Table of Contents (pdf 354 kb)
Chapter 1 - Introduction to the Project (pdf 1.1 mb)
Chapter 2 - Alternatives (pdf 6 mb)
Chapter 3 - Construction Activities (pdf 3.4 mb)
Chapter 4 - The Project Area's Environment (pdf 4.8 mb)
Chapter 5 - Project Operation and Permanent Effects (pdf 9.4 mb)
Chapter 6 - Effects During Construction of the Project (pdf 3.6 mb)
Chapter 7 - Indirect and Cumulative Effects (pdf 3.5 mb)
Chapter 8 - Other Considerations (pdf 567 kb)
Attachments
Attachment 1 - Acronyms and Abbreviations (pdf 139 kb)
Attachment 2 - Index (pdf 124 kb)
Attachment 3 - List of Preparers (pdf 147 kb)
Attachment 4 - Distribution List (pdf 133 kb)
Attachment 5 - References (pdf 210 kb)
Attachment 6 - Draft Section 4(f)/6(f) Evaluation (pdf 9.5 mb)
Attachment 7 - Discipline Reports
Cultural Resources Discipline Report
Vol 1 – Main Text (pdf 5.6 mb)
Vol 2 – Att. 1, Tribal Consultation, and Att. 2, Agency Consultation (pdf 1.1 mb)
Vol 3 – Att. 3, Summary of Pre-1972 Properties/Historic Property Inventory Forms
Vol 4 – Att. 4, Forms for Previously Identified Properties
Ecosystems Discipline Report
Energy Discipline Report (pdf 1.4 mb)
Environmental Justice Discipline Report (pdf 7.8 mb)
Geology and Soils Discipline Report (pdf 6.1 mb)
Hazardous Materials Discipline Report (pdf 6.7 mb)
Indirect and Cumulative Effects Analysis Discipline Report (pdf 6.8 mb)
Land Use, Economics, and Relocations Discipline Report (pdf 6.5 mb)
Navigable Waterways Discipline Report (pdf 3.5 mb)
Noise Discipline Report
Recreation Discipline Report (pdf 4.2 mb)
Social Elements Discipline Report (pdf 4.7 mb)
Transportation Discipline Report
Visual Quality and Aesthetics Discipline Report
Water Resources Discipline Report (pdf 5.6 mb)
Attachment 8 - Range of Alternatives and Options Evaluated (pdf 3 mb)
Attachment 9 - Mitigation Plans
Cultural Resources Discipline Report Vol 4 – Att. 4, Forms for Previously Identified Properties
Communications and public involvement work for the SR 520 Program is summarized in public involvement appendices as part of the environmental documentation for the program's separate projects. Below are links to these documents (all PDFs):
