Final Technical Report Addendum DRAFT Aquatic Resources Technical Report Addendum for the Salem River Crossing Project FEIS Prepared for Oregon Department of Transportation September 2016 Prepared by Contents Section Page Acronyms and Abbreviations ....................................................................................................... vii 1 Introduction ......................................................................................................................... 1-1 1.1 Summary of Project Purpose and Need .............................................................. 1-1 1.2 Description of the Preferred Alternative ............................................................. 1-2 1.2.1 National Environmental Policy Act ........................................................ 1-2 1.2.2 Crossing Location and Bridge Description ............................................ 1-2 1.2.3 Eastside Bridgehead and Distribution Network ................................... 1-2 1.2.4 Westside Bridgehead and Distribution Network ................................. 1-7 1.2.5 Bridge Type .............................................................................................. 1-13 1.2.6 Construction Activities ........................................................................... 1-15 1.2.7 River Traffic .............................................................................................. 1-16 2 Affected Environment ....................................................................................................... 2-1 2.1 General Habitat ....................................................................................................... 2-1 2.1.1 Mid-Willamette River ............................................................................... 2-1 2.1.2 Glenn Creek ................................................................................................ 2-1 2.1.3 Disturbances in the Mid-Willamette Basin ............................................ 2-2 2.1.4 Habitat in the Mid-Willamette Basin ...................................................... 2-3 2.1.5 Hydrology .................................................................................................. 2-4 2.1.6 Morphology ................................................................................................ 2-6 2.1.7 Water Quality ............................................................................................. 2-6 2.1.8 Fishery Resources ...................................................................................... 2-8 3 Data Sources and Data Collection Methods .................................................................. 3-1 3.1 Area of Potential Impact (API) ............................................................................. 3-1 3.2 Methods ................................................................................................................... 3-1 3.3 Data Gathering ........................................................................................................ 3-4 3.3.1 Office Review ............................................................................................. 3-4 3.3.2 Field Investigation ..................................................................................... 3-5 3.4 Analysis Methods ................................................................................................... 3-5 3.4.1 Direct Impacts ............................................................................................ 3-5 3.4.2 Indirect/Secondary Impacts .................................................................... 3-5 3.4.3 Cumulative Impacts .................................................................................. 3-6 3.4.4 Temporary Construction Impacts ........................................................... 3-6 3.5 Assumptions ........................................................................................................... 3-6 4 Impact Analysis .................................................................................................................. 4-1 4.1 Overview of Impact Analysis ............................................................................... 4-1 4.1.1 Past and Present Actions .......................................................................... 4-1 4.1.2 Reasonably Foreseeable Future Actions ................................................ 4-3 4.2 Direct Impacts ......................................................................................................... 4-3 SALEM RIVER CROSSING PROJECT FEIS PAGE III AQUATIC RESOURCES FINAL TECHNICAL REPORT ADDENDUM CONTENTS, CONTINUED Section Page 4.2.1 Individuals ................................................................................................. 4-4 4.2.2 In-Stream Habitat ...................................................................................... 4-4 4.2.3 Riparian Habitat ........................................................................................ 4-8 4.2.4 Benthic Productivity ................................................................................. 4-8 4.2.5 Suspended Sediment and Turbidity ...................................................... 4-9 4.2.6 Impervious Surface Area ......................................................................... 4-9 4.2.7 Water Quality .......................................................................................... 4-10 4.3 Indirect Impacts.................................................................................................... 4-11 4.3.1 Predation .................................................................................................. 4-11 4.3.2 Hydrology ................................................................................................ 4-12 4.3.3 Riparian Functionality ............................................................................ 4-12 4.4 Cumulative Impacts ............................................................................................ 4-13 4.4.1 Past and Present Actions ........................................................................ 4-13 4.4.2 Reasonably Foreseeable Future Actions .............................................. 4-14 4.4.3 Summary of Cumulative Impacts ......................................................... 4-15 4.5 Temporary Construction Impacts...................................................................... 4-16 4.5.1 Individuals ............................................................................................... 4-16 4.5.2 In-Stream Habitat .................................................................................... 4-20 4.5.3 Riparian Habitat ...................................................................................... 4-21 4.5.4 Benthic Productivity ............................................................................... 4-21 4.5.5 Suspended Sediment and Turbidity .................................................... 4-22 4.6 Synthesis of Temporary Construction Impacts ............................................... 4-23 4.7 Mitigation Measures ............................................................................................ 4-25 4.7.1 Direct Impacts ......................................................................................... 4-25 4.7.2 Indirect Impacts ...................................................................................... 4-27 4.7.3 Cumulative Impacts ............................................................................... 4-27 4.7.4 Temporary Construction Impacts ........................................................ 4-27 5 Conclusions (Summary of Impacts) ............................................................................... 5-1 5.1 Affected Environment ........................................................................................... 5-1 5.1.1 Project Setting and Study Area ............................................................... 5-1 5.1.2 Existing Conditions .................................................................................. 5-2 5.2 Impacts and Proposed Mitigation ....................................................................... 5-2 5.2.1 Direct Impacts ........................................................................................... 5-2 5.2.2 Indirect Impacts ........................................................................................ 5-5 5.2.3 Cumulative Impacts ................................................................................. 5-6 5.2.4 Temporary Construction Impacts .......................................................... 5-6 5.2.5 Mitigation Measures ................................................................................. 5-6 5.3 Findings ................................................................................................................... 5-7 5.4 Permits Likely Needed .......................................................................................... 5-7 6 Contacts and Coordination .............................................................................................. 6-1 7 References ........................................................................................................................... 7-1 AQUATIC RESOURCES FINAL TECHNICAL REPORT ADDENDUM PAGE IV SALEM RIVER CROSSING PROJECT FEIS CONTENTS, CONTINUED Section Page Appendixes A Potentially Occurring Federally Listed, Proposed, Candidate Species, and