SR 520, I-5 to Medina: Bridge Replacement and HOV Project
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SUPPLEMENTAL DRAFT ENVIRONMENTAL IMPACT STATEMENT and SECTION 4(F) EVALUATION SR 520 BRIDGE REPLACEMENT AND HOV PROGRAM DECEMBER 2009 SR 520: I-5 to Medina Bridge Replacement and HOV Project Ecosystems Discipline Report � SR 520: I-5 to Medina Bridge Replacement and HOV Project Supplemental Draft EIS Ecosystems Discipline Report Prepared for Washington State Department of Transportation Federal Highway Administration Lead Author Parametrix, Inc. Consultant Team Parametrix, Inc. CH2M HILL HDR Engineering, Inc. Parsons Brinckerhoff ICF Jones & Stokes Cherry Creek Consulting Michael Minor and Associates PRR, Inc. December 2009 I-5 to Medina: Bridge Replacement and HOV Project | Supplemental Draft EIS | Ecosystems Discipline Report Contents SR 520: I-5 to Medina Bridge ........................................................................................................... iii Replacement and HOV Project ....................................................................................................... iii Supplemental Draft EIS ................................................................................................................... iii Acronyms and Abbreviations ........................................................................................................ vii 1. Introduction ................................................................................................................................... 1-1 Why are ecosystems considered in an environmental impact statement? ..................1-1 What are the key points of this report? ............................................................................1-1 What is the I-5 to Medina: Bridge Replacement and HOV Project? .............................1-8 What are the project alternatives? .....................................................................................1-9 2. Wetlands ........................................................................................................................................ 2-1 Affected Environment .........................................................................................................2-1 Potential Effects of the Project .........................................................................................2-19 Mitigation ........................................................................................................................... 2-47 3. Fish and Aquatic Resources ....................................................................................................... 3-1 Affected Environment .........................................................................................................3-1 Potential Effects of the Project .........................................................................................3-26 Mitigation ........................................................................................................................... 3-73 4. Wildlife and Habitat .................................................................................................................... 4-1 Affected Environment .........................................................................................................4-1 Potential Effects of the Project .........................................................................................4-20 Mitigation ........................................................................................................................... 4-65 5. References ...................................................................................................................................... 5-1 Wetlands ............................................................................................................................... 5-2 Fish and Aquatic Resources ...............................................................................................5-3 Wildlife and Habitat ............................................................................................................ 5-8 List of Exhibits 1-1 Key Elements and Potential Effects on Ecosystems of the 6-Lane Alternative, Design Options, and Suboptions 1-2 Project Vicinity Map 1-3 No Build Alternative Cross Section 1-4 6-Lane Alternative Cross Section 1-5 Options A, K, and L—Montlake and University of Washington Areas SDEIS_DR_ECOS_FINAL20091222.DOC iii I-5 to Medina: Bridge Replacement and HOV Project | Supplemental Draft EIS | Ecosystems Discipline Report 1-6 6-Lane Alternative—Evergreen Point Bridge (Common to All Options) 1-7 Possible Towing Route and Pontoon Outfitting Locations 1-8 Geographic Areas along SR 520 and Project Phasing 2-1 Overview of Cowardin Classification System for Wetlands in the Study Area 2-2 Distinguishing Features and Examples of Habitats Using the Cowardin System 2-3 Overview of the Hydrogeomorphic Classification System for Wetlands in the Study Area 2-4 Illustration of the Hydrogeomorphic Classification System 2-5 Washington State Department of Ecology Criteria for Wetland Rating Categories 2-6 Summary of Seattle Wetland Rating System and Standard Buffer Requirements in the Study Area 2-7a Existing Wetlands in the Portage Bay Area 2-7b Existing Wetlands in the Montlake Area 2-8 Summary of Wetlands in the Study Area 2-9 Summary of Wetland Functions in the Study Area 2-10 Summary of Construction Effects on Wetlands and Buffers by Option (in Acres) 2-11a Construction Effects on Wetlands and Buffers in the Portage Bay Area 2-11b Construction Effects on Wetlands and Buffers in the Montlake Area 2-12 Wetland and Buffer Construction Effects by Geographic Area (in Acres) 2-13 Summary of Operational Effects on Wetland and Buffer by Option (in Acres) 2-14a Operational Effects on Wetlands and Buffers in the Portage Bay Area 2-14b Operational Effects on Wetlands and Buffers in the Montlake Area 2-15 6-Lane Alternative Option Profiles 2-16 Approximate Height from the High Water Level to the Underside of Various Portions of the Bridge Structures, by Option 2-17 Wetland and Buffer Operational Effects by Geographic Area (in Acres) 2-18 Summary of Operational Effects on Wetland Functions for all Options 2-19 Potential Mitigation Needs for the Project SDEIS_DR_ECOS_FINAL20091222.DOC iv I-5 to Medina: Bridge Replacement and HOV Project | Supplemental Draft EIS | Ecosystems Discipline Report 3-1 Location of Affected Watersheds and Basins 3-2 Study Area Waterbodies 3-3 Various Shoreline Habitat Areas within the Project Area 3-4 Prevalent Lake Washington Watershed Fish Species and their Ecological Roles 3-5 Identified Sockeye Salmon Spawning Beach 3-6 Features of Streams that Cross the Project Corridor 3-7 Location of Fairweather Creek 3-8 Location of Cozy Cove Creek 3-9 Approximate Acres of Shading from Construction Work Bridges and the Detour Bridge, by Option and Suboption (acres) 3-10 Construction and Operational Effects of Option A and its Suboptions on Open Water 3-11 Estimated Number of Support Piles and Associated Lakebed Occupied for the Construction Work Bridges and Detour Bridge, by Option and Suboption 3-12 Construction and Operational Effects of Option K on Open Water 3-13 Construction and Operational Effects of Option L on Open Water 3-14 Conceptual Plan View of Bridge Maintenance Facility Dock 3-15 Dewatering Cofferdam 3-16 Cross-section of Drilled Shaft Cap and Column Configuration 3-17 Total Area (acres) of Overwater Structure that Would Cause Shading Effects, by Option and Suboption 3-18 Estimated Numbers of Concrete Columns for Portions of the Proposed Bridges and Area of Substrate Occupied, by Option and Suboption 3-19 Pre- and Post-Project Impervious Surface Areas, by Option 3-20 Pollution-Generating Impervious Surface (PGIS) and Stormwater Treatment, by Option 3-21 Net Change in Pollutant Loading from Post-Project Pollution-Generating Impervious Surface (PGIS) Areas, by Option 4-1 Existing Cover Types in the Project Corridor SDEIS_DR_ECOS_FINAL20091222.DOC v I-5 to Medina: Bridge Replacement and HOV Project | Supplemental Draft EIS | Ecosystems Discipline Report 4-2 Study Area Landscape Cover Types, Habitats, and Representative Associated Wildlife 4-3 Occurrence of Wildlife Species of Special Interest in the Study Area 4-4 Bald Eagle Breeding Territories near the Study Area 4-5 Vegetation Removal from Construction by Cover and Habitat Type for each Option (acres) 4-6 Construction Effects of Option A and its Suboptions on Cover Type 4-7 Construction Effects of Options A, K, or L on Cover Type in the Eastside Area 4-8 Vegetation Removal from Construction by Cover and Habitat Type for Suboptions Only (acres) 4-9 Shading from Construction by Cover and Habitat Type for each Option (acres) 4-10 Shading from Construction by Cover and Habitat Type for each Suboption Only (acres) 4-11 Construction Effects of Option K on Cover Type 4-12 Construction Effects of Option L on its Suboptions on Cover Type 4-13 Vegetation Removal from Operation by Cover and Habitat Type for each Option (acres) 4-14 Operational Effects of Option A and its Suboptions on Cover Type 4-15 Operational Effects of Options A, K, or L on Cover Type in the Eastside Area 4-16 Vegetation Removal from Operation by Cover and Habitat Type for Suboptions Only (acres) 4-17 Shading from Operation by Cover and Habitat Type for each Option (acres) 4-18 Shading from Operation by Cover and Habitat Type for Suboptions Only (acres) 4-19 Operational Effects of Option K on Cover Type 4-20 Operational Effects of Option L and its Suboptions on Cover Type 4-21 Summary of Effects from Operation