DRAFT Supplemental Environmental Impact Report for METRO GOLD LINE FOOTHILL EXTENSION Azusa to Montclair (SCH No. 2010121069) Evaluating Station Area Parking Modifications at Glendora, San Dimas, La Verne, Pomona and Claremont September 2020 Metro Gold Line Foothill Extension Construction Authority DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT REPORT FOR THE METRO GOLD LINE FOOTHILL EXTENSION Azusa to Montclair (SCH No. 2010121069) Prepared for: Metro Gold Line Foothill Extension Construction Authority 406 East Huntington Drive, Suite 202 Monrovia, California 91016 Prepared by: AECOM 401 West A Street, Suite 1200 San Diego, California 92101 Phone: (619) 610-7600 September 2020 TABLE OF CONTENTS Section Page Acronyms and Abbreviations ....................................................................................................... ix Executive Summary ................................................................................................................ ES-1 Introduction ................................................................................................................................... 1 1 Project Description .........................................................................................................1-1 1.1 Existing and Operational Gold Line System ....................................................... 1-1 1.2 Azusa to Montclair Extension – Phase 2B Project ............................................. 1-1 1.2.1 2013 FEIR Project with Addenda and the 2019 SEIR ............................ 1-1 1.2.2 Project Modifications............................................................................... 1-2 1.2.3 Anticipated Permits and Approvals ....................................................... 1-16 1.3 Project Objectives ............................................................................................ 1-21 2 Project Alternatives ........................................................................................................2-1 2.1 Alternative Development Process ...................................................................... 2-1 2.1.1 Alternatives Previously Considered ........................................................ 2-1 2.1.2 Alternatives Considered in Draft SEIR .................................................... 2-2 3 Transportation ................................................................................................................3-1 3.1 Introduction .........................................................................................................3-1 3.2 Regulatory Setting .............................................................................................. 3-2 3.2.1 State Regulations ................................................................................... 3-2 3.2.2 Project Modifications Study Area Determination .................................... 3-3 3.2.3 Environmental Impacts ........................................................................... 3-3 3.2.4 Cumulative Impacts .............................................................................. 3-13 3.2.5 Mitigation Measures and Recommendations ........................................ 3-13 3.2.6 Level of Impact After Mitigation ............................................................ 3-15 3.3 Supplemental Analysis (Not required for CEQA analysis) ................................ 3-15 3.3.1 Traffic Operations Methodology ............................................................ 3-15 3.3.2 Intersections Evaluated ........................................................................ 3-17 3.3.3 Model Calibrations ................................................................................ 3-19 3.3.4 Parking Analysis Methodology .............................................................. 3-20 3.3.5 Regional Forecasting ............................................................................ 3-20 3.3.6 Traffic Demand ..................................................................................... 3-21 3.3.7 Long-term Parking Impacts ................................................................... 3-40 3.4 Transportation Conclusion .............................................................................. 3-46 4 Environmental Analysis, Impacts, and Mitigation ........................................................... 4-1 4.1 Air Quality ........................................................................................................ 4.1-1 4.1.1 Regulatory Setting ............................................................................... 4.1-1 4.1.2 Existing Conditions .............................................................................. 4.1-1 Metro Gold Line Foothill Extension–Azusa to Montclair Supplemental Environmental Impact Report i September 2020 4.1.3 Environmental Impacts ........................................................................ 4.1-2 4.1.4 Cumulative Impacts ........................................................................... 4.1-12 4.1.5 Mitigation Measures ........................................................................... 4.1-12 4.1.6 Level of Impact after Mitigation .......................................................... 4.1-14 4.2 Biological Resources/Ecosystems................................................................... 4.2-1 4.2.1 Regulatory Setting ............................................................................... 4.2-1 4.2.2 Existing Conditions .............................................................................. 4.2-1 4.2.3 Environmental Impacts ........................................................................ 4.2-2 4.2.4 Cumulative Impacts ............................................................................. 4.2-5 4.2.5 Mitigation Measures ............................................................................. 4.2-5 4.2.6 Level of Impact after Mitigation ............................................................ 4.2-7 4.3 Climate Change ............................................................................................... 4.3-1 4.3.1 Regulatory Setting ............................................................................... 4.3-1 4.3.2 Existing Conditions .............................................................................. 4.3-4 4.3.3 Environmental Impacts ........................................................................ 4.3-4 4.3.4 Cumulative Impacts ............................................................................. 4.3-8 4.3.5 Mitigation Measures ............................................................................. 4.3-9 4.3.6 Level of Impact after Mitigation ............................................................ 4.3-9 4.4 Communities, Population, and Housing .......................................................... 4.4-1 4.4.1 Regulatory Setting ............................................................................... 4.4-1 4.4.2 Existing Conditions .............................................................................. 4.4-1 4.4.3 Environmental Impacts ........................................................................ 4.4-2 4.4.4 Cumulative Impacts ........................................................................... 4.4-10 4.4.5 Mitigation Measures ........................................................................... 4.4-10 4.4.6 Level of Impact after Mitigation .......................................................... 4.4-11 4.5 Community Facilities and Parklands ............................................................... 4.5-1 4.5.1 Regulatory Setting ............................................................................... 4.5-1 4.5.2 Existing Conditions .............................................................................. 4.5-1 4.5.3 Environmental Impacts ........................................................................ 4.5-2 4.5.4 Cumulative Impacts ............................................................................. 4.5-4 4.5.5 Mitigation Measures ............................................................................. 4.5-5 4.5.6 Level of Impact after Mitigation ............................................................ 4.5-5 4.6 Cultural Resources .......................................................................................... 4.6-1 4.6.1 Regulatory Setting ............................................................................... 4.6-1 4.6.2 Methodology ........................................................................................ 4.6-1 4.6.3 Existing Conditions ............................................................................ 4.6-17 4.6.4 Archaeological Resources ................................................................. 4.6-17 4.6.5 Historic Architectural Resources ........................................................ 4.6-17 4.6.6 Paleontological Resources ................................................................ 4.6-23 4.6.7 Tribal Cultural Resources .................................................................. 4.6-24 4.6.8 Environmental Impacts ...................................................................... 4.6-25 4.6.9 Cumulative Impacts ........................................................................... 4.6-29 4.6.10 Mitigation Measures ........................................................................... 4.6-29 4.6.11 Level of Impact after Mitigation .........................................................