Final Report Photograph: http://www.newington-dover.com Hydraulic Modeling Analysis Spaulding Turnpike Improvements, Little Bay Bridges Newington to Dover, New Hampshire Prepared for: Vanasse Hangen Brustlin, Inc. 6 Bedford Farms Drive, Suite 607 Bedford, New Hampshire 03110-6532 Prepared by: AECOM 500 Southborough Drive South Portland, Maine 04106 September 14, 2010 AECOM Project No. 60145174 AECOM Hydraulic Modeling Analysis September 14, 2010 Spaulding Turnpike Improvements, Little Bay Bridges TABLE OF CONTENTS EXECUTIVE SUMMARY .............................................................................................................................. 1 1 INTRODUCTION ................................................................................................................................... 3 1.1 Project Location .............................................................................................................................. 3 1.2 Project Description .......................................................................................................................... 3 1.2.1 Bridge Description...................................................................................................................... 3 2 EXISTING CONDITIONS MODEL ......................................................................................................... 4 2.1 Model Description ........................................................................................................................... 4 2.1.1 Model Construction .................................................................................................................... 4 2.1.2 Boundary Conditions ................................................................................................................. 5 2.2 Existing Conditions Model Verification ........................................................................................... 5 2.2.1 Tidal Height Verification ............................................................................................................. 6 2.2.2 Velocity Verification.................................................................................................................... 6 3 PREFERRED ALTERNATIVE MODEL ................................................................................................. 8 3.1 Model Description ........................................................................................................................... 8 3.1.1 Model Construction .................................................................................................................... 8 3.1.2 Boundary Conditions ................................................................................................................. 8 3.2 Model Results ................................................................................................................................. 8 3.2.1 Tidal Height Comparison ........................................................................................................... 8 3.2.2 Velocity Comparison .................................................................................................................. 9 4 TEMPORARY CONSTRUCTION CONDITIONS MODEL .................................................................. 11 4.1 Model Description ......................................................................................................................... 11 4.1.1 Model Construction .................................................................................................................. 11 4.1.2 Boundary Conditions ............................................................................................................... 11 4.2 Model Results ............................................................................................................................... 12 4.2.1 Tidal Height Comparison ......................................................................................................... 12 4.2.2 Velocity Comparison ................................................................................................................ 12 5 RECOMMENDATIONS........................................................................................................................ 15 REFERENCES ............................................................................................................................................ 17 APPENDIX A: FIGURES ............................................................................................................................. 18 APPENDIX B: PLANS USED FOR THE PREFERRED ALTERNATIVE MODEL ...................................... 36 APPENDIX C: PLANS USED FOR THE TEMPORARY CONSTRUCTION CONDITIONS MODEL ......... 49 L:\work\60145174\PROJ\Reports\Final Report\FinalMemo(14-Sept-2010).doc i PROJECT NO. 60145174 AECOM Hydraulic Modeling Analysis September 14, 2010 Spaulding Turnpike Improvements, Little Bay Bridges TABLES Table 1. Tidal Height Comparison Summary ................................................................................................ 2 Table 2. Mesh Summary for Existing Conditions Model ............................................................................... 5 Table 3. Tidal Height Verification for Existing Conditions Model .................................................................. 6 Table 4. Velocity Verification for Existing Conditions Model ......................................................................... 7 Table 5. Mesh Summary for Preferred Alternative Model ............................................................................. 8 Table 6. Tidal Height Comparison for Preferred Alternative Model .............................................................. 9 Table 7. Velocity Comparison for Preferred Alternative Model ................................................................... 10 Table 8. Mesh Summary for Temporary Construction Conditions Model ................................................... 12 Table 9. Tidal Height Comparison for Temporary Construction Conditions Model .................................... 12 Table 10. Velocity Verification for Temporary Construction Conditions Model ........................................... 14 Table 11. Tidal Height Comparison Summary ............................................................................................ 16 FIGURES Figure 1. Project Locus Map ....................................................................................................................... 19 Figure 2. Model Extent ................................................................................................................................ 20 Figure 3. Model Bathymetry ........................................................................................................................ 21 Figure 4. Existing Bridge Model Geometry with Mesh ................................................................................ 22 Figure 5. Tidal Boundary Time Series ........................................................................................................ 23 Figure 6. Tidal Height Observation Locations ............................................................................................. 24 Figure 7. Velocity Observation Locations ................................................................................................... 25 Figure 8. Maximum Flood Currents for Existing Conditions ....................................................................... 26 Figure 9. Maximum Ebb Currents for Existing Conditions .......................................................................... 27 Figure 10. Preferred Alternative Model Geometry ...................................................................................... 28 Figure 11. Preferred Alternative Model Geometry with Mesh ..................................................................... 29 Figure 12. Maximum Flood Currents for Preferred Alternative ................................................................... 30 Figure 13. Maximum Ebb Currents for Preferred Alternative ...................................................................... 31 Figure 14. Temporary Construction Conditions Model Geometry .............................................................. 32 Figure 15. Temporary Construction Conditions Model Geometry with Mesh ............................................. 33 Figure 16. Maximum Flood Currents for Temporary Construction Conditions ........................................... 34 Figure 17. Maximum Ebb Currents for Temporary Construction Conditions .............................................. 35 L:\work\60145174\PROJ\Reports\Final Report\FinalMemo(14-Sept-2010).doc ii PROJECT NO. 60145174 AECOM Hydraulic Modeling Analysis September 14, 2010 Spaulding Turnpike Improvements, Little Bay Bridges EXECUTIVE SUMMARY AECOM was contracted by Vanasse Hangen Brustlin, Inc. (VHB) to perform a hydraulic analysis for the proposed design of the Little Bay Bridges connecting Newington to Dover, New Hampshire. The hydraulic analysis was based on a continuation of a computer-based hydrodynamic model constructed by the University of New Hampshire (UNH), Department of Mechanical Engineering, Ocean Engineering Laboratory and bridge plans provided by VHB. The UNH hydrodynamic model, which was constructed for the Environmental Impact Statement (EIS) prepared by VHB in December 2007, was verified