Coastal Erosion, Sediment Transport, and Prioritization Management Strategy Assessment for Shoreline Protection Scituate, Massachusetts August 2016 Photo by Kevin Ham Prepared by: Applied Coastal Research and Engineering, Inc. 766 Falmouth Road, Suite A1 Mashpee, Massachusetts 02649 Prepared for: Town of Scituate 600 Chief Justice Cushing Highway Scituate, Massachusetts 02066 Massachusetts Office of Coastal Zone Management 251 Causeway Street, Suite 800 Boston, Massachusetts 02114 Prioritization Management Strategy for Shoreline Protection Scituate, MA TABLE OF CONTENTS 1.0 Introduction ................................................................................................................... 1 1.1 Analysis of Coastal Change and Sediment Transport Processes ................................. 2 1.2 Assessment of Historical Storm Damage Based on Storm Severity ............................. 4 1.3 Development of Prioritization Criteria for Coastal Resiliency ........................................ 4 1.4 Determination of Appropriate Shore Protection and/or Coastal Management Approaches ................................................................................................................. 5 1.5 Evaluation of Shore Protection and/or Management Strategies by Shoreline Stretch ........................................................................................................................ 6 1.6 Public Working Sessions.............................................................................................. 6 2.0 Historical Coastal Change ............................................................................................ 7 2.1 Shoreline Change Analysis .......................................................................................... 8 2.2 Topographic/Bathymetric Change Analysis .................................................................16 3.0 Wave and Sediment Transport Modeling ....................................................................26 3.1 Wave and Wind Data ..................................................................................................26 3.2 SWAN Model Development ........................................................................................27 3.3 Sea Level Rise Considerations ...................................................................................37 3.4 Sediment Transport and Shoreline Evolution Modeling ...............................................39 3.4.1 Formulation of Sediment Transport and Shoreline Model ....................................40 3.4.2 Model Calibration Example ..................................................................................42 4.0 Historical Storm Damage .............................................................................................49 4.1 FEMA Repetitive Loss Claims by Storm (1978-2015) .................................................50 4.2 Selected Storms .........................................................................................................52 4.2.1 Blizzard of 1978 ...................................................................................................54 4.2.2 1991 No-Name Storm ..........................................................................................56 4.2.3 Recent Storms – Winter Storm Nemo (2013) and Winter Storm Juno (2015) .......58 5.0 Prioritization Criteria ....................................................................................................63 5.1 Study Areas ................................................................................................................63 5.2 Damage Susceptibility of Private Properties................................................................66 5.3 Landform Elevation .....................................................................................................72 5.4 Damage Susceptibility of Public Utilities ......................................................................74 5.5 Emergency Egress ......................................................................................................79 5.6 Breaching Potential .....................................................................................................80 5.7 Coastal Engineering Structure Condition ....................................................................83 5.8 Prioritization Matrix .....................................................................................................86 6.0 Engineered Shore Protection Approaches .................................................................88 6.1 Maintain Status Quo ...................................................................................................88 6.2 Seawalls and Revetments ...........................................................................................90 6.3 Beach Nourishment ....................................................................................................96 6.4 Constructed Dunes .....................................................................................................99 6.5 Offshore Breakwaters ...............................................................................................101 6.6 Boulder Dike .............................................................................................................104 6.7 Elevate Road ............................................................................................................107 i Prioritization Management Strategy for Shoreline Protection Scituate, MA 6.8 Drainage Improvements for the Basins .....................................................................108 6.9 Protection Improvements for Pump Stations .............................................................109 6.10 Managed Retreat ......................................................................................................110 6.11 Elevate Buildings ......................................................................................................111 6.12 Other Innovative Approaches ....................................................................................111 7.0 Shore Protection Approaches by Study Area ..........................................................116 7.1 Minot Beach ..............................................................................................................117 7.2 North Scituate Beach ................................................................................................123 7.3 Surfside Road ...........................................................................................................127 7.4 Mann Hill Beach ........................................................................................................129 7.5 Egypt Beach .............................................................................................................132 7.6 Oceanside Drive .......................................................................................................136 7.7 Cedar Point ...............................................................................................................140 7.8 First Cliff ...................................................................................................................145 7.9 Edward Foster Road ................................................................................................. 147 7.10 Second Cliff ..............................................................................................................151 7.11 Peggotty Beach ........................................................................................................153 7.12 Third Cliff ..................................................................................................................163 7.13 Fourth Cliff ................................................................................................................166 7.14 Humarock North ........................................................................................................167 7.15 Humarock South .......................................................................................................176 8.0 References ..................................................................................................................181 Glossary of Terms ................................................................................................... Glossary-1 Appendix A ............................................................................................................................ A-1 Appendix B ............................................................................................................................ B-1 Appendix C ............................................................................................................................ C-1 Appendix D ............................................................................................................................ D-1 Appendix E ............................................................................................................................ E-1 Appendix F ............................................................................................................................ F-1 ii Prioritization Management Strategy for Shoreline Protection Scituate, MA LIST OF FIGURES Figure 1.1 Map of Massachusetts showing the location and orientation of the Scituate coastline. ...........................................................................................................