VILLAGE OF BALD HEAD ISLAND SHORELINE PROTECTION PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT

Transcription

1 VILLAGE OF BALD HEAD ISLAND SHORELINE PROTECTION PROJECT DRAFT ENVIRONMENTAL IMPACT STATEMENT Prepared By: U.S. Army Corps of Engineers Wilmington District and Land Management Group, Inc. (Third Party Contractor) January 2014

2 DRAFT Environmental Impact Statement January 2014 TABLE OF CONTENTS 1.0 PROJECT PURPOSE Purpose and Need Statement Project Goal and Objectives Project Location Inlet and Shoreline Management to Date Wilmington Harbor Entrance Channel and the Sand Management Plan Summary of Beach Disposal and Nourishment Events Sand Tube Groinfield Sand Bag Revetment Summary of EIS Process Permits, Licenses and Entitlements National Environmental Policy Act of Rivers and Harbors Act of Migratory Bird Treaty Act of Fish and Wildlife Coordination Act of National Historic Preservation Act of Clean Water Act of Coastal Zone Management Act of Endangered Species Act of Coastal Barrier Resources Act and Coastal Barrier Improvement Act of Magnuson Stevens Fishery Conservation and Management Act North Carolina Environmental Policy Act North Carolina Coastal Area Management Act of North Carolina Dredge and Fill Law North Carolina Surface and Water Quality Standards Ownership of Lands North Carolina Senate Bill 110 and Senate Bill SCOPING Summary of Scoping Project Review Team Issues Identified During Scoping i

3 3.0 PROJECT ALTERNATIVES Screening of Alternatives Description of Alternatives No Action/Status Quo Alternative (Alternative #1) Retreat (Alternative #2) Beach Nourishment/Disposal (Existing Sand Tube Groinfield Remaining) (Alternative #3) A. Wilmington Harbor Entrance Channel B. Jay Bird Shoals C. Bald Head Creek Shoals D. Frying Pan Shoals Beach Nourishment/Disposal (Existing Sand Tube Groinfield Removal) (Alternative #4) Terminal Groin with Beach Nourishment/Disposal (Sand Tube Groinfield Remaining) (Alternative #5) Description of Alternate # Terminal Groin Design Goals and Precepts Terminal Groin Design Details Terminal Groin Construction Methods Terminal Groin with Beach Nourishment/Disposal (Sand Tube Groinfield Removal) AFFECTED ENVIRONMENT General Environmental Setting Geology and Morphology of Study Area Sand Source and Quality A. Wilmington Harbor Entrance Channel B. Jay Bird Shoals C. Bald Head Creek Shoal D. Frying Pan Shoals Threatened and Endangered Species Mammals Birds Reptiles A. Hawksbill Sea Turtle, Kemp s Ridley Sea Turtle, and Leatherback Sea Turtle B. Loggerhead Sea Turtle C. Green Sea Turtle Fish A. Atlantic Sturgeon B. Shortnose Sturgeon Plants Permit Area Habitats Estuarine A. Salt Marsh ii

4 B. Unvegetated Subtidal and Intertidal Bottom Coastal Beach and Dune Habitats A. Wet Beach B. Dry Beach C. Dune D. Interdunal Wetlands E. Maritime Shrub/Maritime Forest Marine Habitats A. Soft Bottom Communities B. Hardbottom Communities Water Column Water Quality Air Quality Public Safety Aesthetic Resources Recreational Resources Navigation Historic Properties and Cultural Resources Socio Economic Considerations Land Use Hydrodynamics Tides and Tidal Flow Tidal Prism River Discharge Waves A. Measured Wave Data B. WIS Data Analysis of Sediment Transport Pathways A. Bald Head Island B. Channel Shoaling C. Transport Along Oak Island D. Olsen Associates 2012 Study Sea Level Rise Infrastructure Urban Quality Solid Waste Drinking Water Non Relevant Resources Hazardous, Toxic and Radioactive Waste Noise iii

5 5.0 ENVIRONMENTAL CONSEQUENCES Alternatives Eliminated from Further Consideration Description of Predicted Physical Effects Shoreline Conditions A. Methodology B. Findings Beach Conditions Duneline Conditions Sand Volume Requirements and Borrow Sites General Environmental Consequences No Action/Status Quo Retreat Beach Nourishment/Disposal with Existing Sand Tube Groinfield to Remain in Place Beach Nourishment/Beach Disposal and Sand Tube Groinfield Removal Terminal Groin with Beach Nourishment/Beach Disposal(Sand Tube Groinfield Remaining) Terminal Groin with Beach Nourishment/Beach Disposal and Removal of Sand Tube Groinfield Threatened and Endangered Species Alternative #1: No Action/Status Quo A. Mammals B. Birds C. Reptiles D. Fish E. Plants Alternative #2: Retreat A. Mammals B. Birds C. Reptiles D. Fish E. Plants Alternative #3: Beach Nourishment/Beach Disposal with Existing Sand Tube Groinfield to Remain in Place A. Mammals B. Birds C. Reptiles D. Fish E. Plants Alternative #4: Beach Nourishment/Beach Disposal and Sand Tube Groinfield Removal A. Mammals B. Birds C. Reptiles iv

6 D. Fish E. Plants Alternative #5: Terminal Groin with Beach Nourishment/Beach Disposal (Sand Tube Groinfield Remaining) A. Mammals B. Birds C. Reptiles D. Fish E. Plants Alternative #6: Terminal Groin with Beach Nourishment/Beach Disposal (Removal of Sand Tube Groinfield) A. Mammals B. Birds C. Reptiles D. Fish E. Plants Permit Area Habitats Estuarine A. Salt Marsh Coastal Beach and Dune Habitats A. Wet Beach B. Dry Beach C. Dune D. Interdunal Wetlands E. Maritime Thicket/Forest Marine Habitats A. Soft Bottom Communities B. Hardbottom Communities Water Column Water Quality Air Quality Public Safety Aesthetic Resources Recreational Resources Navigation Background Waves Currents Shoaling Historic Properties and Cultural Resources v

7 5.14 Socio Economic Considerations Introduction Costs Considerations of Alternative Actions Summary of Economic Analysis Land Use Hydrodynamics Infrastructure Background Predicted Effects to Infrastructure Urban Quality Solid Waste Drinking Water Non Relevant Resources Hazardous, Toxic and Radioactive Waste Noise Compliance with Environmental Requirements AVOIDANCE, MINIMIZATION AND MITIGATIVE MEASURES Terminal Groin Design Construction Methods and Sequencing Post Construction Monitoring Cultural Resource Avoidance Avoidance and Minimization to Threatened and Endangered Species Sea Turtles Manatees Whales Sturgeon Piping Plover Seabeach Amaranth REFERENCES vi

8 LIST OF FIGURES 1.1. Vicinity Map 1.2. Ocean Bar Realignment 1.3. Sand Tube Groinfield 3.1. Lots Available for Relocation Retreat Alternative # Potential Sand Source Areas 4.1. Study Area Biological Resources 4.2. Study Area Physical Monitoring 4.3. Study Area Delft3D Modeling 4.4. Bald Head Island Shoreline Positions (1855 to 1926) 4.5. Bald Head Island Shoreline Positions ( ) 4.6. Bald Head Island Shoreline Positions (1989 and 1996) 4.7. Existing Habitat Area Mapping 4.8. Habitat Area Mapping Potential Sand Sources (1) 4.9. Habitat Area Mapping Potential Sand Sources (2) Ocean Hardbottom Mapping NC Marine Fisheries Commission Primary Nursery Area Mapping (1) NC Marine Fisheries Commission Primary Nursery Area Mapping (2) Lower Cape Fear River Watershed, Basin Lower Cape Fear River Subbasin CAMA Land Use Plan Existing Land Use Map CAMA Land Use Plan Future Land Use Map FEMA Floodzone and CBRA Mapping Predicted Tides for Ebb and Flood Velocities Computed by FLOW on April 25, Residual Flow Vectors Computed for a One Month, Tide Only Simulation Aerial Photographs of Bald Head Island Measured Daily Discharge at the Cape Fear River, Location of Wave and/or Wind Measurement Stations Wave Data at NOAA Buoy Located Southeast of Frying Pan Shoals Wave Data at the USACE 11 mile ADCP Gauge Located Inside Frying Pan Shoals Wave Data at the Oak Island ADCP Gauge Located Inside Frying Pan Shoals Wave Data at the Bald Head ADCP Gauge Located Inside Frying Pan Shoals WIS Hindcast Stations Relative to the Cape Fear Entrance and Measured Data Wave Roses Depicting Hindcast and Measured Wave Conditions in the Study Area Computed Sediment Transport Patterns along Bald Head Island Reaches of the Federal Navigation Channel Which Routinely Shoal with Beach Compatible Material vii

9 4.32. USACE Condition Surveys of the Navigation Channel in the Cape Fear Entrance, 2003 to Present Directional Distribution of the Wave Height at the Oak Island ADCP Relative to the Island s Dominant Shoreline Orientation of 15 Degrees Physical Monitoring Data Collected and Published by USACE at the Hot Spot along Caswell Beach Overlay of Measured Areas of Chronic Channel Shoaling Along with Predicted Vectors of Sediment Transport Sea Level Trends at Southport, NC ( ) Adapted from the NOAA Online Data Archive CAMA Land Use Plan Infrastructure Map 5.1. Predicted MLLW Shoreline after a 9 year Simulation for Each Alternative 5.2. Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Predicted Cumulative Sedimentation and Erosion after 9 Years for Alternative Estimated MHHW Shorelines after a 9 Year simulation of Each Alternative 5.9. Predicted 3 Year Cumulative Erosion and Sedimentation for the Sand Filled Tube Groin Plus Beach Fill Scenario Hypothetical Cumulative Volume Changes along the Respective Fill Placement Areas for Project Alternatives Maximum Dune Elevation between Survey Baseline STA 0+00 and Current Habitat Area Mapping and Predicted 9 Yr MHHW Shorelines Yr MHHW Alternative #1 Existing Habitat Areas Yr MHHW Alternative #1 Predicted Habitat Areas Yr MHHW Alternative #2 Existing Habitat Areas Yr MHHW Alternative #2 Predicted Habitat Areas Yr MHHW Alternative #3 Existing Habitat Areas Yr MHHW Alternative #3 Predicted Habitat Areas Yr MHHW Alternative #4 Existing Habitat Areas Yr MHHW Alternative #4 Predicted Habitat Areas Yr MHHW Alternative #5 Existing Habitat Areas Yr MHHW Alternative #5 Predicted Habitat Areas Yr MHHW Alternative #6 Existing Habitat Areas Yr MHHW Alternative #6 Predicted Habitat Areas Peak Ebb Tidal Flow Computed following 1 Month Tide Only Simulation under Terminal Groin with 1.2Mcy Beach Fill and Tube Groins Conditions Direct Comparison of Peak Flood Velocities for With and Without Terminal Groin Conditions viii

10 5.27. Direct Comparison of Peak Ebb Flows for With and Without Terminal Groin Conditions Predicted Cumulative Channel Shoaling within the Limits of Baldhead Shoal Channels 1 and 2 after 9 Years for Each Considered Alternative Predicted Change in Channel Shoaling within Baldhead Shoal Channels 1 and 2 relative to that predicted for Alternative At Risk Property Assessment Predicted Shorelines, All Alternatives At Risk Property Alternative # At Risk Property Alternative # At Risk Property Alternative # At Risk Property Alternative # At Risk Property Alternative # At Risk Property Alternative # Infrastructure Impacts Predicted Shorelines, All Alternatives LIST OF TABLES 1.1. Cape Fear River Entrance Channel improvements ( ) 1.2. Beach Fill Placement Events on South Beach, Bald Head Island (since 1991) 2.1. Project Review Team Members 3.1. List of Project Alternatives 4.1. List of Federally and State Protected Species Known to Occur in the Vicinity of the Study Area 4.2. Tidal Datums for Bald Head Island, NC 4.3. Maximum Magnitude of Mean Flows at Inlet Transect 4.4. Measured (Normalized) Tidal Prism Values , adapted from USACE 2011a 5.1. List of Project Alternatives. 5.2 Predicted Volumetric Changes in the Project Area after Three Years 5.3. Predicted Percentage of Initial Fill Volume Remaining after Three Years 5.4. Predicted Percentage of Fill Remaining West of Station after Three Years 5.5. Predicted Sand Volume Requirements (by Alternative) 5.6. Predicted Losses or Gains by Habitat Type and Alternative 5.7. Scope of Costs and Benefits by Alternative ix

11 LIST OF APPENDICES Appendix A. SB151 Legislation Appendix B. Inlet Management Plan Appendix C. Scoping Documents Appendix D. USACE Hydrographic Surveys Appendix E. Project Design Drawings (Proposed Action) Appendix F. Design Engineering Analysis for Terminal Groin Length Appendix G. South Amelia Island Terminal Groin Aerial Photographs Appendix H. Archaeological Survey and SHPO Letter Appendix I. Bald Head Island Historic Aerial Imagery Appendix J. Bird Nesting Data ( ) Appendix K. Station Location Map Appendix L. Environmental Consequences Summary Table by Alternative Appendix M. Fish Larvae Response Model Appendix N. Sea Turtle Nesting Locations ( ) Appendix O. Understanding the Costs and Benefits of Shoreline Change Appendix P. Storm Response Simulation Appendix Q. Cumulative Effects Analysis x