East Aberdeen Mobility Project Preferred Alternative Selection Report April 2015 Prepared for : Grays Harbor Council of Governments Prepared by: East Aberdeen Mobility Project Preferred Alternative Selection Report April 2015 Prepared for: Grays Harbor Council of Governments Prepared by: Contents EXECUTIVE SUMMARY ................................................................................................................................... I Background ....................................................................................................................................... I Work Completed to Date: ................................................................................................................ II Substantive Findings ....................................................................................................................... III Project Development ...................................................................................................................... III Conclusion ....................................................................................................................................... IV EAST ABERDEEN MOBILITY PROJECT ............................................................................................................ 1 1. BACKGROUND ............................................................................................................................. 1 1.1. Project Study Area ................................................................................................................ 1 1.2. Project Partners .................................................................................................................... 3 1.3. Project Description ................................................................................................................ 4 2. Concept Development ................................................................................................................ 5 2.1. Data Gathering ...................................................................................................................... 5 2.2. Concept Development Process Overview ............................................................................. 5 2.3. Top Three Design Concepts Descriptions ............................................................................. 7 2.3.1. Alternative A – Heron Street Flyover ............................................................................ 7 2.3.2. Alternative B – Benn Street Modified Texas-T ............................................................ 10 2.3.3. Alternative C – Chehalis Street Overcrossing .............................................................. 12 2.4. Geometric Design ................................................................................................................ 14 2.4.1. Horizontal Design ........................................................................................................ 14 2.4.2. Vertical Design ............................................................................................................ 15 2.5. Utilities ................................................................................................................................ 15 2.6. Geotechnical Investigations ................................................................................................ 15 2.7. Structures ............................................................................................................................ 17 2.7.1. Bridge Structure .......................................................................................................... 17 2.7.2. Retaining Walls............................................................................................................ 17 2.8. Traffic Operations ............................................................................................................... 17 2.9. Environmental Considerations ............................................................................................ 18 2.9.1. Wetlands and Streams ................................................................................................ 18 2.9.2. Water Resources ......................................................................................................... 19 2.9.3. Land Use and Acquisition ............................................................................................ 19 2.9.4. Noise ........................................................................................................................... 20 2.9.5. Visual Quality .............................................................................................................. 21 2.9.6. Cultural and Archaeological Resources ....................................................................... 21 2.9.7. Hazardous Materials ................................................................................................... 22 2.10. Construction .................................................................................................................... 23 2.10.1. Construction Staging and Impacts ............................................................................. 23 2.10.2. Construction Timing .................................................................................................. 24 2.11. Public Involvement .......................................................................................................... 24 2.11.1. Priorities and Preferences ......................................................................................... 25 2.11.2. Additional Information .............................................................................................. 26 2.12. Construction Costs .......................................................................................................... 26 3. Conclusion and Recommendations .......................................................................................... 27 Conclusion ...................................................................................................................................... 27 Recommendation ........................................................................................................................... 27 APPENDICES ........................................................................................................................................ 28 Appendix A: Initial Design Concepts .............................................................................................. 28 Appendix B: Geometric Design ...................................................................................................... 28 Appendix C: Geotechnical .............................................................................................................. 28 Appendix D: Traffic ........................................................................................................................ 28 Appendix E: Environmental............................................................................................................ 28 Appendix F: Cultural Resources ..................................................................................................... 28 Appendix G: Hazardous Materials ................................................................................................. 28 Appendix H: Public Involvement .................................................................................................... 28 Appendix I: Project Costs ............................................................................................................... 28 Appendix J: Top Three Alternatives Exhibits .................................................................................. 28 Appendix K: Top Three Alternatives Criteria Ranking .................................................................... 28 East Aberdeen Mobility Project David Evans and Associates, Inc. Preferred Alternative Selection Report i April, 2015 FIGURES Figure 1: Vicinity Map ................................................................................................................................... 1 Figure 2: Study Limits .................................................................................................................................... 2 Figure 3: East Aberdeen Traffic Map ............................................................................................................ 2 Figure 4: Organizational Chart ...................................................................................................................... 3 Figure 5: Alternative A (Heron Street Flyover) Rendering ............................................................................ 8 Figure 6: Alternative A Traffic Circulation ..................................................................................................... 9 Figure 7: Alternative A Cross Section (Looking East) .................................................................................... 9 Figure 8: Alternative B (Benn St. Modified Texas-T) Rendering ................................................................. 10 Figure 9: Alternative B Traffic Circulation ................................................................................................... 11 Figure 10: Alternative B Cross Section (Looking West) ............................................................................... 11 Figure