OCS Study 

MMS 2000-056

FINAL REPORT 

COLLECTION OF ENVIRONMENTAL DATA WITHIN SAND 

RESOURCE AREAS OFFSHORE NORTH CAROLINA AND 

THE ENVIRONMENTAL IMPLICATIONS OF SAND REMOVAL 

FOR COASTAL AND BEACH RESTORATION

Volume I: Main Text 

 Prepared by: In Cooperation with: 

Applied Coastal Research and Engineering, Inc. Continental Shelf Associates, Inc. 

 766 Falmouth Road, Suite A-1 Barry A. Vittor & Associates, Inc. 

 Mashpee, MA 02649 Germano & Associates, Inc. 

 

Prepared for: 

U.S. Department of the Interior 

Minerals Management Service

Leasing Division

Sand and Gravel Unit

Funded Under Contract Number 1435-01-97-CT-30843 
 

DISCLAIMER 

This report has been reviewed by the Minerals Management Service and approved for 

publication. Approval does not signify that the contents necessarily reflect the views and 

policies of the Service, nor does mention of trade names or commercial products constitute 

endorsement or recommendation for use. 

SUGGESTED CITATION 

Byrnes, M.R., R.M. Hammer, B.A. Vittor, S.W. Kelley, D.B. Snyder, J.M. Côté, J.S. Ramsey, 

T.D. Thibaut, N.W. Phillips, J.D. Wood, and J.D. Germano, 2003. Collection of Environmental 

Data Within Sand Resource Areas Offshore North Carolina and the Environmental Implications 

of Sand Removal for Coastal and Beach Restoration. U.S. Department of the Interior, Minerals 

Management Service, Leasing Division, Sand and Gravel Unit, Herndon, VA. OCS Report 

MMS 2000-056, Volume I: Main Text 256 pp. + Volume II: Appendices 69 pp.
FINAL REPORT 

COLLECTION OF ENVIRONMENTAL DATA WITHIN SAND 

RESOURCE AREAS OFFSHORE NORTH CAROLINA AND THE 

ENVIRONMENTAL IMPLICATIONS OF SAND REMOVAL FOR 

COASTAL AND BEACH RESTORATION 

September 2003 

Mark R. Byrnes 

Physical Processes Project Manager, Co-Editor 

(Applied Coastal Research and Engineering, Inc.) 

Richard M. Hammer 

Biological Component Project Manager, Co-Editor 

(Continental Shelf Associates, Inc.) 

With Contributions from: 

Barry A. Vittor 

Barry A. Vittor & Associates, Inc. 

Sean W. Kelley 

Applied Coastal Research and Engineering, Inc. 

David B. Snyder 

Continental Shelf Associates, Inc. 

Jessica M. Côté 

Applied Coastal Research and Engineering, Inc.

John S. Ramsey 

Applied Coastal Research and Engineering, Inc.

Tim D. Thibaut 

Barry A. Vittor & Associates, Inc. 

Neal W. Phillips 

Continental Shelf Associates, Inc. 

Jon D. Wood 

Applied Coastal Research and Engineering, Inc. 

Joseph D. Germano

Germano & Associates, Inc. 

Prepared by: Prepared for:

Applied Coastal Research and Engineering, Inc. U.S. Department of the Interior 

766 Falmouth Road, Suite A-1 Minerals Management Service 

Mashpee, MA 02649 Leasing Division

Sand and Gravel Unit

381 Elden Street, MS 4030 

In Cooperation with: Herndon, VA 22070 

Continental Shelf Associates, Inc. 

Barry A. Vittor & Associates, Inc. 

Germano & Associates, Inc. 

Contract Number 1435-01-97-CT-30843 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

i

ACKNOWLEDGMENTS 

 Numerous people contributed to the project titled Collection of Environmental Data Within Sand 

Resource Areas Offshore North Carolina and the Environmental Implications of Sand Removal for 

Coastal and Beach Restoration, which was funded by the U.S. Department of Interior, Minerals 

Management Service (MMS), Leasing Division, Sand and Gravel Unit. Mr. Barry S. Drucker provided 

assistance and direction during the project as the MMS Contracting Officer’s Technical Representative. 

Ms. Jane Carlson served as the MMS Contracting Officer. 

 Dr. Mark R. Byrnes of Applied Coastal Research and Engineering, Inc. (Applied Coastal) served as 

Project Manager; Physical Processes Component Manager; authored Sections 1.0 (Introduction), 2.1 

(Offshore Sedimentary Environment), 3.0 (Regional Geomorphic Change), 7.1 (Offshore Sand Resource 

Areas), and 7.4.1 (Historical Sediment Transport Patterns); co-authored with Dr. Richard M. Hammer 

Sections 7.7 (Potential Cumulative Effects) and 8.0 (Conclusions); and was Co-Editor of the report. Dr. 

Richard M. Hammer of Continental Shelf Associates, Inc. (CSA) served as the Biological Component 

Manager; authored Sections 7.5.1 (Effects of Offshore Dredging on Benthic Fauna) and 7.5.2 

(Recolonization Rate and Success); and was Co-Editor of the report. 

 Other Applied Coastal personnel who participated in the project included Mr. Sean W. Kelley and 

Mr. John S. Ramsey who co-authored Sections 2.2.4 (Waves and Wave-Generated Currents), 2.2.5 

(Nearshore Sediment Transport), 4.0 (Assessment of Wave Climate Impact by Offshore Borrow Sites), 

5.2 (Offshore Sediment Transport), 7.2 (Wave Transformation Modeling, 7.4.2 (Sediment Transport 

Modeling at Potential Borrow Sites), and 7.4.3 (Nearshore Sediment Transport Potential). Ms. Jessica M. 

Côté and Mr. Jon D. Wood co-authored Sections 2.2.1 (Tidal Currents), 2.2.2 (Wind-Generated Currents), 

2.2.3 (Density-Driven Currents), 5.1 (Currents and Circulation), 5.1.2 (Summary of Flow Regimes at 

Offshore Borrow Sites), and 7.3 (Currents and Circulation). Ms. Jessica L. Baker and Ms. Feng Li were 

responsible for shoreline and bathymetric change data compilation and surface modeling. Ms. Shelley 

Johnston assisted with report preparation related to background literature on the offshore sedimentary 

environment. Ms. Elizabeth Hunt was responsible for report compilation and editorial assistance during 

production of the report. 

 Other CSA personnel who contributed to the project included Mr. David B. Snyder, who served as 

Chief Scientist during Biological Field Surveys 1 and 2; authored Sections 2.3.2.1 and 

7.6.1 (Zooplankton), 2.3.2.2 and 7.6.2 (Squids), and 2.3.2.3 and 7.6.3 (Fishes); and incorporated sections 

from other authors concerning infauna, epifauna and demersal fishes, and discussion into the remainder 

of Section 6.0 (Biological Field Surveys) that he authored. Dr. Alan D. Hart led the sampling design and 

statistical analyses for the biological data. Dr. Neal W. Phillips wrote Sections 2.3.2.4 and 7.6.4 (Sea 

Turtles) and 2.3.2.5 and 7.6.5 (Marine Mammals), and reviewed the report. Mr. Paul S. Fitzgerald served 

as a Field Scientist during Biological Field Surveys 1 and 2. Mr. Thomas Quinney served as Scientist 

during Survey 1. Mr. Frederick B. Ayer, III directed the field surveys and pre-plotted the station locations. 

Mr. Lynwood R. Powell, Jr. produced the field survey post-plot figures. Ms. Melody B. Powell provided 

editorial assistance and supervised CSA support staff during production of the report. 

 Personnel from Barry A. Vittor & Associates, Inc. (BVA) contributing to the project included Dr. 

Barry A. Vittor, who served as Manager of BVA's responsibilities for the field surveys and report. Mr. Tim 

D. Thibaut authored Sections 2.3.1.1 and 6.3.4 (Infauna), 2.3.1.2 and 6.3.5 (Epifauna and Demersal 

Fishes), 6.4 (Discussion), and 7.5.3 (Predictions Relative to the Sand Resource Areas) of the report, with 

assistance from Dr. Vittor. Mr. J. Dobbs Lee served as Scientist during both field surveys. Ms. Linda W. 

Sierke supervised personnel associated with taxonomic identifications. Mr. Felix Fernandez served as 

Manager for BVA's benthic infaunal data entry and analyses. 

Dr. Joseph D. Germano from Germano & Associates, Inc. (formerly from EVS Environment 

Consultants [EVS]) was responsible for the sediment profiling camera aspects of the project. Mr. Tim 

Hammermiester of Science Applications International Corporation (formerly from EVS) served as the 

sediment profiling camera Field Scientist during Surveys 1 and 2. Dr. Wayne C. Isphording from the 

University of South Alabama conducted the laboratory grain size analyses. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

ii

TABLE OF CONTENTS 

VOLUME I: MAIN TEXT 

1.0 INTRODUCTION................................................................................................................. 1

1.1 STUDY AREA AND BORROW SITE CHARACTERISTICS............................................. 2

1.2 STUDY PURPOSE.......................................................................................................... 5

1.3 STUDY APPROACH ....................................................................................................... 6

1.3.1 Ecological Conditions................................................................................................ 6

1.3.2 Benthic Infaunal Evaluation....................................................................................... 7

1.3.3 Project Scheduling .................................................................................................... 7

1.3.4 Wave Modifications................................................................................................... 7

1.3.5 Sediment Transport Patterns .................................................................................... 7

1.4 DOCUMENT ORGANIZATION........................................................................................ 8

2.0 ENVIRONMENTAL SETTING............................................................................................. 9

2.1 OFFSHORE SEDIMENTARY ENVIRONMENT ............................................................. 13

2.1.1 Seabed Morphology.................................................................................................13

2.1.2 Surface Sediment ....................................................................................................20

2.1.3 Subsurface Deposits................................................................................................22

2.1.4 Sand Resources ......................................................................................................26

2.2 GENERAL CIRCULATION ............................................................................................ 29

2.2.1 Tidal Currents ..........................................................................................................30

2.2.2 Wind-Generated Currents ........................................................................................30

2.2.3 Density-Driven Currents...........................................................................................32

2.2.4 Waves and Wave-Generated Currents.....................................................................32

2.2.5 Nearshore Sediment Transport ................................................................................33

2.3 BIOLOGY ...................................................................................................................... 33

2.3.1 Benthic Environment................................................................................................33

2.3.1.1 Infauna ..............................................................................................................33

2.3.1.2 Epifauna and Demersal Fishes..........................................................................37

2.3.2 Pelagic Environment ................................................................................................38

2.3.2.1 Zooplankton.......................................................................................................39

2.3.2.2 Ichthyoplankton .................................................................................................40

2.3.2.3 Squids ...............................................................................................................42

2.3.2.4 Fishes................................................................................................................44

2.3.2.5 Sea Turtles ........................................................................................................46

2.3.2.6 Marine Mammals ...............................................................................................49

3.0 REGIONAL GEOMORPHIC CHANGE ..............................................................................54

3.1 SHORELINE POSITION CHANGE................................................................................ 54

3.1.1 Previous Studies ......................................................................................................54

3.1.2 Shoreline Position Data Base...................................................................................56

3.1.3 Historical Change Trends.........................................................................................56

3.1.3.1 1849/51 to 1949.................................................................................................59

3.1.3.2 1949 to 1980 .....................................................................................................62

3.1.3.3 Cumulative Shoreline Position Change (1849/51 to 1980).................................64

3.2 NEARSHORE BATHYMETRY CHANGE....................................................................... 65

3.2.1 Bathymetry Data Base and Potential Errors .............................................................65

3.2.2 Digital Surface Models .............................................................................................66
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3.2.2.1 1862/68/70 Bathymetric Surface........................................................................67

3.2.2.2 1970/75/96 Bathymetric Surface........................................................................67

3.2.3 Shelf Sediment Transport Dynamics ........................................................................70

3.2.4 Magnitude and Direction of Change.........................................................................72

3.2.5 Net Longshore Sand Transport Rates......................................................................74

3.3 SUMMARY .................................................................................................................... 74

4.0 WAVE TRANSFORMATION NUMERICAL MODELING AND NEARSHORE SEDIMENT 

TRANSPORT ...................................................................................................................75

4.1 ANALYSIS APPROACH ................................................................................................ 78

4.1.1 Wave Modeling ........................................................................................................78

4.1.1.1 Input Spectra Development ...............................................................................79

4.1.1.2 Grid Development..............................................................................................83

4.1.2 Sediment Transport Potential...................................................................................86

4.2 MODEL RESULTS ........................................................................................................ 87

4.2.1 Wave Modeling ........................................................................................................87

4.2.2 Sediment Transport Potential...................................................................................95

4.2.2.1 Littoral Drift Comparison with Existing Studies...................................................97

4.2.2.2 Model Comparison with Historical Shoreline Change.......................................102

4.2.2.3 Significance of Proposed Dredging..................................................................103

4.3 SUMMARY .................................................................................................................. 105

5.0 CIRCULATION AND OFFSHORE SEDIMENT................................................................107

TRANSPORT DYNAMICS..............................................................................................107

5.1 CURRENTS AND CIRCULATION ............................................................................... 107

5.1.1 Historical Data Analysis .........................................................................................107

5.1.1.1 Description of Observed Currents....................................................................107

5.1.1.2 Numerical Decomposition of Historical Current Data .......................................108

5.1.1.3 Current Components .......................................................................................110

5.1.2 Summary of Flow Regimes at Offshore Borrow Sites.............................................114

5.2 OFFSHORE SEDIMENT TRANSPORT....................................................................... 114

5.2.1 Determining Bottom Transport and Infilling Rates ..................................................116

5.2.2 Model Input Data....................................................................................................118

5.2.3 Infilling Model Results ............................................................................................119

6.0 BIOLOGICAL FIELD SURVEYS .....................................................................................121

6.1 BACKGROUND........................................................................................................... 121

6.2 METHODS .................................................................................................................. 121

6.2.1 Survey Design........................................................................................................121

6.2.1.1 Infauna and Sediment Grain Size ....................................................................128

6.2.1.2 Epifauna ..........................................................................................................129

6.2.1.3 Water Column..................................................................................................129

6.2.2 Field Methods ........................................................................................................129

6.2.2.1 Vessel..............................................................................................................129

6.2.2.2 Navigation .......................................................................................................129

6.2.2.3 Water Column..................................................................................................129

6.2.2.4 Sediment Grain Size........................................................................................130

6.2.2.5 Sediment Profiling Camera..............................................................................130

6.2.2.6 Infauna ............................................................................................................130

6.2.2.7 Epifauna and Demersal Fishes........................................................................130

6.2.3 Laboratory Methods ...............................................................................................130

6.2.3.1 Sediment Grain Size........................................................................................130
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

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6.2.3.2 Sediment Profiling Camera..............................................................................131

6.2.3.3 Infauna ............................................................................................................136

6.2.4 Data Analysis.........................................................................................................136

6.2.4.1 Water Column..................................................................................................136

6.2.4.2 Sediment Grain Size........................................................................................136

6.2.4.3 Sediment Profiling Camera..............................................................................136

6.2.4.4 Infauna ............................................................................................................136

6.2.4.5 Epifauna and Demersal Fishes........................................................................137

6.3 RESULTS.................................................................................................................... 138

6.3.1 Water Column........................................................................................................138

6.3.2 Sediment Grain Size ..............................................................................................138

6.3.3 Sediment Profiling Camera ....................................................................................143

6.3.3.1 Area 1..............................................................................................................143

6.3.3.2 Area 2..............................................................................................................155

6.3.3.3 Area 3..............................................................................................................155

6.3.3.4 Area 4..............................................................................................................166

6.3.3.5 Adjacent Stations.............................................................................................166

6.3.4 Infauna...................................................................................................................175

6.3.4.1 Cluster Analysis...............................................................................................179

6.3.4.2 Canonical Discriminant Analysis......................................................................182

6.3.4.3 Area 1..............................................................................................................182

6.3.4.4 Area 2..............................................................................................................184

6.3.4.5 Area 3..............................................................................................................186

6.3.4.6 Area 4..............................................................................................................186

6.3.5 Epifauna and Demersal Fishes ..............................................................................189

6.4 DISCUSSION .............................................................................................................. 190

7.0 POTENTIAL EFFECTS....................................................................................................197

7.1 POTENTIAL SAND BORROW SITES ......................................................................... 197

7.2 WAVE TRANSFORMATION MODELING.................................................................... 198

7.3 CURRENTS AND CIRCULATION ............................................................................... 200

7.4 SEDIMENT TRANSPORT ........................................................................................... 200

7.4.1 Historical Sediment Transport Patterns..................................................................201

7.4.2 Sediment Transport Modeling at Potential Borrow Sites.........................................201

7.4.3 Nearshore Sediment Transport Potential ...............................................................202

7.5 BENTHIC ENVIRONMENT.......................................................................................... 203

7.5.1 Effects of Offshore Dredging on Benthic Fauna .....................................................203

7.5.1.1 Sediment Removal ..........................................................................................203

7.5.1.2 Sediment Suspension/Dispersion ....................................................................205

7.5.1.3 Sediment Deposition........................................................................................206

7.5.2 Recolonization Rate and Success..........................................................................207

7.5.2.1 Adaptations for Recolonization and Succession ..............................................207

7.5.2.2 Successional Stages .......................................................................................207

7.5.2.3 Recolonization Rates.......................................................................................208

7.5.2.4 Recolonization Success and Recovery............................................................210

7.5.3 Predictions Relative to the Sand Resource Areas..................................................211

7.5.3.1 Potential Benthic Effects..................................................................................211

7.5.3.2 Potential Recolonization Rate and Success.....................................................213

7.6 PELAGIC ENVIRONMENT.......................................................................................... 215

7.6.1 Zooplankton ...........................................................................................................215

7.6.1.1 Entrainment .....................................................................................................215
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

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7.6.1.2 Turbidity...........................................................................................................216

7.6.1.3 Project Scheduling...........................................................................................217

7.6.2 Squids....................................................................................................................218

7.6.2.1 Entrainment .....................................................................................................218

7.6.2.2 Attraction .........................................................................................................218

7.6.2.3 Project Scheduling...........................................................................................218

7.6.3 Fishes ....................................................................................................................218

7.6.3.1 Entrainment .....................................................................................................218

7.6.3.2 Attraction .........................................................................................................218

7.6.3.3 Turbidity...........................................................................................................218

7.6.3.4 Project Scheduling...........................................................................................219

7.6.3.5 Essential Fish Habitat......................................................................................219

7.6.4 Sea Turtles ............................................................................................................222

7.6.4.1 Entrainment .....................................................................................................222

7.6.4.2 Habitat Modification .........................................................................................222

7.6.4.3 Turbidity and Anoxia........................................................................................223

7.6.4.4 Noise ...............................................................................................................223

7.6.4.5 Project Scheduling Considerations ..................................................................223

7.6.5 Marine Mammals ...................................................................................................224

7.6.5.1 Physical Injury .................................................................................................224

7.6.5.2 Turbidity...........................................................................................................224

7.6.5.3 Noise ...............................................................................................................224

7.6.5.4 Project Scheduling Considerations ..................................................................225

7.7 POTENTIAL CUMULATIVE EFFECTS........................................................................ 225

8.0 CONCLUSIONS...............................................................................................................226

8.1 WAVE TRANSFORMATION MODELING.................................................................... 226

8.2 CIRCULATION AND SEDIMENT TRANSPORT DYNAMICS ...................................... 227

8.2.1 Historical Sediment Transport Patterns..................................................................228

8.2.2 Sediment Transport at Potential Borrow Sites........................................................229

8.2.3 Nearshore Sediment Transport Modeling...............................................................229

8.3 BENTHIC ENVIRONMENT.......................................................................................... 230

8.4 PELAGIC ENVIRONMENT.......................................................................................... 231

9.0 LITERATURE CITED.......................................................................................................233
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

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vi 

VOLUME II: APPENDICES 

APPENDIX A. HIGH-WATER SHORELINE POSITION CHANGE ........................................A-1

APPENDIX B. WAVE TRANSFORMATION NUMERICAL MODELING................................B-1

B1. EXISTING CONDITIONS WAVE TRANSFORMATION RESULTS ..............................B-1

B2. WAVE HEIGHT DIFFERENCE PLOTS: POST-DREDGING VERSUS EXISTING ...B-10

CONDITIONS ............................................................................................................B-10

APPENDIX C. BIOLOGICAL FIELD SURVEY DATA ...........................................................C-1

C1. SAMPLE TYPES, SAMPLE CODES, COORDINATES, AND WATER DEPTHS..........C-1

C2. WATER COLUMN PROFILE DATA .............................................................................C-7

C3. SEDIMENT GRAIN SIZE DATA...................................................................................C-9

C4. SEDIMENT PROFILE CAMERA DATA......................................................................C-11

C5. INFAUNAL DATA.......................................................................................................C-16
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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MMS Study 2000-056 

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LIST OF FIGURES 

Figure 1-1. Location diagram illustrating sand resource areas and Federal-State 

boundary offshore Dare County, NC. .................................................................. 2

Figure 1-2. Location diagram illustrating potential sand borrow sites relative to shelf 

morphology offshore Dare County, NC. .............................................................. 4

Figure 2-1. The northern coast Outer Banks of North Carolina (from Pilkey et al., 

1998). ................................................................................................................. 9

Figure 2-2. Inlet locations along the Outer Banks (Cleary and Marden, 1999)..................... 10

Figure 2-3. Looking north from Oregon Inlet to southern Bodie Island................................. 10

Figure 2-4. Shoreline change rate for the northern North Carolina barrier island coast 

(from Dolan and Lins, 1986).............................................................................. 11

Figure 2-5. Sand fences constructed by the Civilian Conservation Corps along the 

Outer Banks in 1933 (from Dolan and Lins, 1986)............................................. 12

Figure 2-6. Rates of sea level rise along the east coast of the United States (from 

Inman and Dolan, 1989) based on Aubrey and Emery (1983)........................... 12

Figure 2-7. Trend for Mean Sea Level (MSL) elevations at Duck, NC (NOAA Station 

Number 8651370), 1986 to 2002. ..................................................................... 13

Figure 2-8. Migration of Old Currituck Inlet in relation to False Cape Shoals (from 

McBride and Moslow, 1991).............................................................................. 15

Figure 2-9. Seismic profiles in the vicinity of Platt Shoals (from Snyder, 1993).................... 16

Figure 2-10. Distribution of seismic and side scan sonar track lines (black lines) and 

vibracore locations (red-filled circles) offshore Dare County, NC (from 

Boss and Hoffman, 2001). ................................................................................ 17

Figure 2-11. Sonogram illustrating smooth, light gray (fine sand) surface (from Boss et 

al., 1999)........................................................................................................... 18

Figure 2-12. Sonograms illustrating light gray and rippled medium-coarse sand (dark 

gray) surface (from Boss et al., 1999). .............................................................. 18

Figure 2-13. Sonograms illustrating patchwork surface pattern; mix of fine and 

medium-coarse sand on slopes of ridges (from Boss et al., 1999). ................... 19

Figure 2-14. Sonograms illustrating pock marked surface pattern existing in the 

northern part of the study area associated with outcropping mud and sand 

lenses (from Boss et al., 1999).......................................................................... 19

Figure 2-15. Sonogram illustrating scarps that occur occasionally on the shelf surface. 

Boss et al. (1999) interpreted these features as resistant material, 

probably cohesive mud, exposed on slopes (from Boss et al., 1999). ............... 20

Figure 2-16. Distribution of primary sediment types as determined from sonogram 

patterns in the study area (from Boss and Hoffman, 2001). .............................. 21

Figure 2-17. Sidescan sonar of the northern coast of North Carolina (from USGS, 

2001). ............................................................................................................... 22

Figure 2-18. Paleodrainage system in coastal North Carolina (from Riggs et al., 1995). 

The area of greatest interest for this sand resources study is the 

Roanoke-Albermarle drainage system. ............................................................. 23

Figure 2-19. Areal extent and depth to seismic reflector R1 (from Boss and Hoffman, 

2001). ............................................................................................................... 24

Figure 2-20. Portion of seismic reflection profile 080 near the intersection of line 132 

illustrating the north (left) and south (right) margins of channel seismic 

facies S1 (from Boss et al., 2002). .................................................................... 25
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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Figure 2-21. Structure contour map and isopach map for unit S2. The channel system 

defined by reflector R1 (shown in light blue) cuts through unit S2 (from 

Boss and Hoffman, 2001). ................................................................................ 25

Figure 2-22. Diagram illustrating geological data and identified potential sand resource 

areas (from Hoffman, 1998). ............................................................................. 26

Figure 2-23. Selected seismic profiles crossing potential sand resource targets 

offshore North Carolina (from Hoffman, 1998). See Figure 2-22 for 

location information........................................................................................... 27

Figure 2-24. Illustration of the six representative lithofacies from offshore vibracores 

(see Figure 2-22 for core location; from Boss and Hoffman, 2001). .................. 28

Figure 2-25. Time series of the along-shelf wind stress (negative is equatorward); 

significant wave height in 8-m water depth; and the subtidal depthaveraged, along-shelf current at the five mooring sites. Offshore 

distances of mooring sites are in parentheses (from Lentz et al., 1999)............ 31

Figure 2-26. Variations in sand transport potential between Cape Henry, VA and Cape 

Hatteras, NC (from Inman and Dolan, 1989)..................................................... 34

Figure 3-1. Sediment type, shoreline change, and direction of net littoral drift along 

the Outer Banks of North Carolina (from Inman and Dolan, 1989). ................... 55

Figure 3-2. Shoreline change rates and standard deviations of position change from 

about 1850 to 1980 between Cape Henry, VA and Cape Hatteras, NC 

(from Everts et al., 1983)................................................................................... 57

Figure 3-3. Shoreline changes adjacent to Oregon Inlet, NC for five surveys between 

1852 and 1980 (from Everts et al., 1983).......................................................... 58

Figure 3-4. Erosion rate analysis for the period 1940 to 1992/95 for Dare County, NC 

(from Overton et al., 1999)................................................................................ 59

Figure 3-5. Shoreline position and change between the FRF Pier and Oregon Inlet, 

NC, 1849/51 to 1915/16.................................................................................... 61

Figure 3-6. Shoreline position and change between the Nags Head and Oregon Inlet, 

NC, 1915/16 to 1949......................................................................................... 61

Figure 3-7. Shoreline position and change between the Nags Head and Oregon Inlet, 

NC, 1849/51 to 1949......................................................................................... 62

Figure 3-8. Shoreline position and change along southern Bodie Island, NC, 1949 to 

1962.................................................................................................................. 63

Figure 3-9. Shoreline position and change along southern Bodie Island, NC, 1949 to 

1975.................................................................................................................. 63

Figure 3-10. Shoreline position and change between the Nags Head and Oregon Inlet, 

NC, 1949 to 1980.............................................................................................. 64

Figure 3-11. Shoreline position and change between the FRF Pier and northern Pea 

Island, just south of Oregon Inlet, NC, 1849/51 to 1980. ................................... 65

Figure 3-12. Nearshore bathymetry (1862/68/70) for offshore Dare County, NC................... 68

Figure 3-13. Nearshore bathymetry (1970/75/96) for offshore Dare County, NC................... 69

Figure 3-14. Aerial photograph of Oregon Inlet illustrating the extent of ebb and flood 

shoal development............................................................................................ 70

Figure 3-15. Nearshore bathymetry change (1862/68/70 to 1970/75/96) for offshore 

Dare County, NC............................................................................................... 71

Figure 3-16. Polygon geometry and locations used for estimating infilling rates (blue) 

relative to sand borrow site locations offshore North Carolina........................... 73

Figure 4-1. Example of results for spatial/temporal variability method for determining 

significance of borrow site dredging impacts (Kelley et al., 2001). Plots of 

modeled net transport potential and post-dredging change in transport for 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

ix

borrow sites located offshore Sandbridge, Virginia. Middle plot shows 

dredging significance criterion envelope (±σ) determined for this 

shoreline. The left plot of the shoreline is given for reference........................... 77

Figure 4-2. Diagram of wave and current vectors used in STWAVE. Subscript a

denotes values in the absolute frame of reference, and subscript r

denotes values in the relative frame of reference (with currents)....................... 79

Figure 4-3. Shoreline of southern Virginia and North Carolina with coarse grid limits 

and WIS wave input data station used to determine dredging impacts 

from offshore sand mining................................................................................. 80

Figure 4-4. Wave height and period roses for hindcast data from WIS Station AU2056 

for the 20-year period between January 1976 and December 1995. 

Direction indicates from where waves were traveling, relative to true 

north. Radial length of gray tone segments indicate percent occurrence 

of each range of wave heights and periods. Combined length of 

segments in each sector indicate percent occurrence of all waves from 

that direction. .................................................................................................... 81

Figure 4-5. WAVETRAN model output for WIS Station AU2056 data transformed to 

offshore boundary of STWAVE numerical grid. Directions are relative to 

STWAVE grid orientation, where 90° corresponds to 66° true north, and 

0° corresponds to 336° true north. .................................................................... 81

Figure 4-6. Example of STWAVE input spectrum developed using WIS 20-year 

hindcast data together with the Goda method of computing frequency and 

direction spectrum. Plots show a) frequency distribution of energy at 

peak direction, b) directional distribution of energy at peak frequency, and 

c) surface plot of two-dimensional energy spectrum. Example is model 

Case 5 (Hmo = 0.9 m, θmean = 130° grid relative). ............................................... 83

Figure 4-7. Color contour plot of coarse model grid (200 m x 200 m grid spacing) 

used with STWAVE. Depths are relative to NVGD 29. Borrow site 

locations are indicated by solid black lines, and fine grid limits are 

indicated by a dashed line................................................................................. 84

Figure 4-8. Color contour plot of fine model grid (20 m x 20 m grid spacing) used with 

STWAVE. Depths are relative to NGVD 29. Borrow site location is 

indicated by solid black line, and fine grid limits are indicated by dashed 

line.................................................................................................................... 85

Figure 4-9. Example STWAVE output for coarse grid (200 m x 200 m cell) model of 

offshore North Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 sec). Color 

contours show Hmo wave height. Vectors indicate wave mean direction. 

Bottom bathymetry contours are shown as light black lines. Fine grid 

limits are indicated by dashed line. ................................................................... 88

Figure 4-10. Example STWAVE output for fine grid (20 m x 20 m cell) model of 

offshore North Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 sec). Color 

contours show Hmo wave height. Vectors indicate wave mean direction. 

Bottom bathymetry contours are shown as light black lines. Fine grid 

limits are indicated by dashed line. ................................................................... 89

Figure 4-11. Wave height difference plot between existing and post-dredging 

conditions (Hdifference = Hpost – Hpre) for coarse grid (200 m x 200 m cell) 

model of offshore North Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 

sec) , for run which included excavation at Sites 1, 2, 3 west, and 4. 

Bottom bathymetry contours are shown as light black lines. ............................. 91
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Figure 4-12. Wave height difference plot between existing and post-dredging 

conditions (Hdifference = Hpost – Hpre) for fine grid (20 m x 20 m cell) model of 

offshore North Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 sec), for 

run which included excavation at Sites 1, 2, 3 west, and 4. Bottom 

bathymetry contours are shown as light black lines. Fine grid limits are 

indicated by dashed line.................................................................................... 92

Figure 4-13. Plot of STWAVE model output for offshore North Carolina wave Case 2 

(Hs = 1.9 m, Tpeak = 6.0 sec, θpeak = 21 deg). Color contours indicate wave 

height, and vectors show mean direction of wave propagation.......................... 93

Figure 4-14. Plot of STWAVE model output for offshore North Carolina wave Case 8 

(Hs = 1.5 m, Tpeak = 12.8 sec, θpeak = 71 deg). Color contours indicate 

wave height, and vectors show mean direction of wave propagation. ............... 94

Figure 4-15. Plot of wave height change between existing and post-dredging (∆ = HpostHpre) conditions at Borrow Sites 3 east and 3 west for STWAVE model 

output for offshore North Carolina wave Case 2 (Hs = 1.9 m, Tpeak = 6.0 

sec, θpeak = 21 deg)............................................................................................ 96

Figure 4-16. Plot of wave height change between existing and post-dredging (∆ = HpostHpre) conditions at Borrow Sites 3 east and 3 west for STWAVE model 

output for offshore North Carolina wave Case 8 (Hs = 1.5 m, Tpeak = 12.8 

sec, θpeak = 71 deg)............................................................................................ 97

Figure 4-17. Plot of computed transport potential for existing conditions, and transport 

potential difference between existing and post-dredging conditions for 

modeled cases where Sites 3 east and 3 west are included alternately. 

The middle plot shows computed net and gross south and north directed 

transport for wave conditions derived from 20-year WIS hindcast. The 

right-hand plot shows change in transport from existing to post-dredging 

conditions, for Sites 1, 2, and 4, modeled with 3 east and 3 west 

separately. ........................................................................................................ 99

Figure 4-18. Wave energy flux (ECn) and sand transport potential along the Hatteras 

littoral cell, using wave climate data from the original WIS Phase III 

simulations (from Inman and Dolan, 1989)...................................................... 100

Figure 4-19. WIS Phase III hindcast data for Station 83, for the simulation period from 

January 1956 through December 1975. Directions are relative to 

approximate shoreline orientation (340°) at Duck, NC (20° on these plots 

corresponds to 0° true north). ......................................................................... 100

Figure 4-20. WAVETRAN output using WIS Station AU2056. Wave record is refracted 

into 10 m water depth corresponding to WIS Phase III depth. Directions 

are relative to approximate shoreline orientation (340°) at Duck, NC (20° 

on these plots corresponds to 0° true north).................................................... 101

Figure 4-21. Duck FRF data for 8 m directional wave array (January 1990 to 

December 1999). Directions are relative to approximate shoreline 

orientation (340°) at Duck, NC (20° on these plots corresponds to 0° true 

north). ............................................................................................................. 101

Figure 4-22. Histogram of relative wave energy for wave records divided into six 

directional bins. Bar length is determined by the product of percent 

occurrence and squared mean wave height of each directional bin. 

Directions are relative to approximate shoreline orientation (340°) at 

Duck, NC (20° on this plot corresponds to 0° true north)................................. 102
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Figure 4-23. Comparison of historical shoreline change and gradient of modeled 

transport potential (dQ/dy) for the North Carolina shoreline. Color bars 

indicate whether the shoreline is accretional, stable, or erosional. .................. 104

Figure 4-24. Plot of transport potential difference between existing and post-dredging 

conditions, including the maximum influence envelope. .................................. 106

Figure 5-1. Vertical profile of average and maximum current speeds from January 

through December 1997. Maximum currents were directed southerly at 

150 cm/sec (≈ 3 knots) in the upper water column and 100 cm/sec (≈ 2 

knots) near bottom.......................................................................................... 108

Figure 5-2. Rose diagram of currents measured at the surface (1.25 m), mid-depth 

(6.75 m), and near-bottom (11.75 m). Rings represent 10%, 20% and 

30% occurrence, and shading corresponds to current speed ranges as 

denoted by the scale....................................................................................... 108

Figure 5-3. Histogram showing the relative energy (variance) of separated current 

components; high-frequency, tides, wind-driven, and low-frequency flows. 

Units are (cm/sec)2

. Along-shelf wind-driven currents contained the most 

energy at the surface and near-bottom for both time periods. ......................... 111

Figure 5-4. Winds measured at the end of the FRF pier in Duck, NC at an elevation of 

19.36 m (NGVD) presented in rose diagrams for three time periods. .............. 112

Figure 5-5. Time series of wind speed and direction, and the subtidal component of 

cross-shelf and along-shelf currents, for a two-week period in May 1997........ 113

Figure 5-6. Time series of wind speed and direction, and the subtidal component of 

cross-shelf and along-shelf currents, for a two-week period in October 

1997................................................................................................................ 113

Figure 5-7. Rose diagrams of wind, wind-driven currents, and low-frequency currents 

during two time periods in 1997: May to September and October to 

December. ...................................................................................................... 115

Figure 6-1. Sampling locations for Adjacent Stations R1 and R2 relative to the four 

sand resource areas and the North Carolina coast. ........................................ 123

Figure 6-2. Sampling locations for North Carolina Sand Resource Area 1. ....................... 124

Figure 6-3. Sampling locations for North Carolina Sand Resource Area 2. ....................... 125

Figure 6-4. Sampling locations for North Carolina Sand Resource Area 3. ....................... 126

Figure 6-5. Sampling locations for North Carolina Sand Resource Area 4. ....................... 127

Figure 6-6. Temperature and salinity profiles recorded by Hydrolab during the May 

1998 survey in the four sand resource areas offshore North Carolina............. 139

Figure 6-7. Temperature and dissolved oxygen profiles recorded by Hydrolab during 

the May 1998 survey in the four sand resource areas offshore North 

Carolina. ......................................................................................................... 140

Figure 6-8. Temperature and salinity profiles recorded by Hydrolab during the 

September 1998 survey in the four sand resource areas offshore North 

Carolina. ......................................................................................................... 141

Figure 6-9. Temperature and dissolved oxygen profiles recorded during the 

September 1998 survey in the four sand resource areas offshore North 

Carolina. ......................................................................................................... 142

Figure 6-10. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) 

and camera prism penetration depth (Survey 1) based on sediment 

profiling in North Carolina Sand Resource Area 1........................................... 144

Figure 6-11. a. Sediment profile image from Station 14, Area 1, May 1998, Survey 1 

showing the presence of bedforms and a grain size major mode of 3 to 2 

phi (image width represents 15 cm). b. Sediment profile image from 
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Station 15, Area 1, May 1998, Survey 1 showing the presence of 

bedforms and a grain size major mode of 4 to 3 phi (image width 

represents 15 cm)........................................................................................... 145

Figure 6-12. Sediment profile image from Station 16, Area 1, May 1998, Survey 1 

showing poorly-sorted sediments with shell hash not only on the sediment 

surface but admixed down to a depth of 7 cm (image width represents 15 

cm).................................................................................................................. 146

Figure 6-13. Sediment profile image from Station 6, Area 1, May 1998, Survey 1 

showing well-sorted sediments in the very-fine-to-fine-sand range; note 

the hermit crab on the sediment surface (image width represents 15 cm)....... 147

Figure 6-14. Sediment profile image from Station 17, Area 1, May 1998, Survey 1 

showing a distinct demarcation between the coarse surface layer and 

underlying fine sands (image width represents 15 cm).................................... 148

Figure 6-15. Sediment profile image from Station 13, Area 1, May 1998, Survey 1; 

boundary roughness values from all images in Area 1 were primarily due 

to surface relief from the physical forces that created the sand ripples 

present throughout the area (image width represents 15 cm).......................... 149

Figure 6-16. Sediment profile image from Station 20, Area 1, May 1998, Survey 1; 

note that grain size is similar to that of other images, but prism 

penetration is greater, which is a function of lowered sediment shear 

strength (image width represents 15 cm). ....................................................... 150

Figure 6-17. Sediment profile image from Station 5, Area 1, May 1998, Survey 1 

showing an extensive network of subsurface burrow structures created by 

errant infauna (image width represents15 cm). ............................................... 151

Figure 6-18. Sediment profile image from Station 2, Area 1, May 1998, Survey 1 

showing tubicolous polychaetes projecting above the sediment-water 

interface (image width represents 15 cm). ...................................................... 152

Figure 6-19. Sediment profile image from Station 3, Area 1, May 1998, Survey 1 with 

thin, white polychaete palp (arrow) being retracted back to the animal, 

which is below prism penetration depth (image width represents 15 cm). ....... 153

Figure 6-20. Sediment profile image from Station 8, Area 1, May 1998, Survey 1; the 

darker areas on the sediment surface are mats of benthic diatoms (image 

width represents 15 cm).................................................................................. 154

Figure 6-21. Sediment profile image from Station 2, Area 1, September 1998, Survey 2 

showing surface roughness elements caused by infaunal burrowing 

activity; the crater-like rim of a large burrow opening can be seen in the 

left background of the image (image width represents 15 cm)......................... 156

Figure 6-22. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) 

and camera prism penetration depth (Survey 1) based on sediment 

profiling in North Carolina Sand Resource Area 2........................................... 157

Figure 6-23. Sediment profile image from Station 1, Area 2, May 1998, Survey 1 

showing the presence of bedforms and a grain size major mode of 4 to 3 

phi (image width represents 15 cm). ............................................................... 158

Figure 6-24. Sediment profile image from Station 4, Area 2, May 1998, Survey 1 

showing a thin surface deposit of fine-grained material with a grain size 

>4 phi (image width represents 15 cm). .......................................................... 159

Figure 6-25. Sediment profile image from Station 2, Area 2, May 1998, Survey 1; 

arrows point to fecal casts on the sediment surface from infaunal deposit 

feeders (image width represents 15 cm). ........................................................ 160
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Figure 6-26. Sediment profile image from Station 4, Area 2, September 1998, Survey 

2; arrows indicate traces of linear burrows and places where the camera 

prism has transected subsurface burrow structures (image width 

represents 15 cm)........................................................................................... 161

Figure 6-27. Sediment profile image from Station 2, Area 2, September 1998, Survey 2 

showing a crab's eyes peering just above the sediment surface at the 

camera lens (image width represents 15 cm).................................................. 162

Figure 6-28. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) 

and camera prism penetration depth (Survey 1) based on sediment 

profiling in North Carolina Sand Resource Area 3........................................... 163

Figure 6-29. a. Sediment profile image from Station 6, Area 3, May 1998, Survey 1 

showing the presence of shell fragments and a grain size major mode of 

1 to 0 phi (image width represents 15 cm). b. Sediment profile image 

from Station 7, Area 3, May 1998, Survey 1 showing the presence of 

bedforms and a grain size major mode of 4 to 3 phi (image width 

represents 15 cm)........................................................................................... 164

Figure 6-30. Sediment profile image from Station 5, Area 3, May 1998, Survey 1 

showing a layer of fine sand on top of a silt/clay foundation (image width 

represents 15 cm)........................................................................................... 165

Figure 6-31. Sediment profile image from Station 3, Area 3, May 1998, Survey 1 

showing a surface feeding pit most likely caused by an infaunal 

polychaete with a J-shaped tube (image width represents 15 cm). ................ 167

Figure 6-32. Sediment profile image from Station 2, Area 3, May 1998, Survey 1 

showing an assemblage of large tubicolous polychaetes with tubes 

ornamented with shell fragments (image width represents 15 cm). ................. 168

Figure 6-33. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) 

and camera prism penetration depth (Survey 1) based on sediment 

profiling in North Carolina Sand Resource Area 4........................................... 169

Figure 6-34. Sediment profile image from Station 4, Area 4, May 1998, Survey 1 

showing a representative image of sediment conditions in the entire area; 

bedforms were present throughout this region, and all stations had a grain 

size major mode of 4 to 3 phi (image width represents 15 cm)........................ 170

Figure 6-35. Sediment profile image from Station 5, Area 4, May 1998, Survey 1 

showing a surface diatom layer (image width represents 15 cm). ................... 171

Figure 6-36. Sediment profile image from Station 10, Area 4, May 1998, Survey 1 

showing a shallow subsurface burrow at the left side of the image (image 

width represents 15 cm).................................................................................. 172

Figure 6-37. Sediment profile image from Station 7, Area 4, May 1998, Survey 1 

showing a thin depositional layer of fine-grained material on a sandy 

bottom (image width represents 15 cm). ......................................................... 173

Figure 6-38. Sediment profile image from Adjacent Station 2, May 1998, Survey 1 

showing the presence of shell fragments and a grain size major mode of 

2 to 1 phi (image width represents 15 cm)....................................................... 174

Figure 6-39. Station groups (A to D, and X) based on normal cluster analysis of 

infaunal samples collected during the May 1998 Survey 1 and September 

1998 Survey 2 in the four sand resource areas and two adjacent stations 

offshore North Carolina................................................................................... 180

Figure 6-40. Grain size composition of infaunal samples collected during the May 1998 

Survey 1 (S1) and September 1998 Survey 2 (S2) in the four sand 
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resource areas (A1, A2, A3, A4) and two adjacent stations (R1 and R2) 

offshore North Carolina................................................................................... 193

Figure 6-41. Comparison of grain size estimates between sediment profile camera and 

Smith-McIntyre grabs. (a) Sediment grain size classes plotted for each 

station sampled by sediment profile camera during the May 1998 Survey 

1 and September 1998 Survey 2 offshore North Carolina; (b) modal grain 

size plotted for each station sampled by Smith-McIntyre grab during the 

May 1998 Survey 1 and September 1998 Survey 2 offshore North 

Carolina. ......................................................................................................... 196
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LIST OF TABLES 

Table 1-1. Sand Resource Characteristics at Potential Borrow Sites in Resource 

Areas Offshore North Carolina............................................................................ 5

Table 2-1. Potential sand resource dimensions for the four primary sand targets 

(from Boss and Hoffman, 2001). ....................................................................... 29

Table 2-2. Summary of spawning times and location of fishes in the central part of 

the Middle Atlantic Bight (Adapted from: Able and Fahay, 1998)....................... 41

Table 2-3. Ranking of the most abundant larval fishes collected in continental shelf 

waters in the central part of the Middle Atlantic Bight during the Marine 

Monitoring, Assessment and Prediction Program (MARMAP) surveys 

from 1977 to 1987 (Adapted from: Able and Fahay, 1998)................................ 43

Table 2-4. Sea turtle species potentially occurring in coastal North Carolina waters. 

Species are listed in order of relative abundance.............................................. 47

Table 2-5. Species of marine mammals potentially occurring in North Carolina 

coastal waters. Key: (X) presence likely during at least some season; 

(o) presence possible but unlikely due to geographic range, preference 

for deeper waters, or uncommon occurrence.................................................... 50

Table 3-1. Summary of shoreline source data characteristics for the North Carolina 

coast between Kitty Hawk and Oregon Inlet...................................................... 60

Table 3-2. Positional uncertainty estimates associated with North Carolina shoreline 

surveys. ............................................................................................................ 60

Table 3-3. Maximum root-mean-square uncertainties for North Carolina shoreline 

change data...................................................................................................... 60

Table 3-4. Summary of bathymetric source data characteristics for the offshore area 

between Duck and Oregon Inlet, NC................................................................. 66

Table 3-5. Sand volume extraction from potential borrow sites relative to computed 

infilling rates...................................................................................................... 72

Table 4-1. Significant parameters of input wave spectra used for existing and postdredging STWAVE model runs. Storm input conditions are for a 

simulated 10-year event.................................................................................... 83

Table 4-2. Comparison of wave energy distribution between updated WIS record 

(transformed into 10 m water depth), FRF 8 m array record, and original 

WIS Phase III record. Absolute difference values show percentage 

difference of FRF 8 m array and original WIS Phase III record compared 

to updated WIS record (Station AU2056). ....................................................... 101

Table 5-1. Wave model input conditions used to compute offshore sediment 

transport potential. STWAVE model output, from each modeled 

condition, and at each borrow site perimeter grid node was used as input 

into wave-current interaction model used to determine bottom sediment 

transport potential. .......................................................................................... 118

Table 5-2. Surface currents used for modeling bottom sediment transport and the 

determination of borrow site infilling rates. Current data from Duck FRF 

13 m ADCP, using one-year record from Jan 1997 to Jan 1998...................... 119

Table 5-3. Borrow site characteristic depths and bottom sediment grain sizes used 

as bottom sediment transport potential model input. ....................................... 119

Table 5-4. Characteristic dimensions, computed borrow site infilling rates, and 

estimated time to fill based on total proposed excavated volume. ................... 120

Table 6-1. Sampling plan for the North Carolina May 1998 Survey 1 and September 

1998 Survey 2................................................................................................. 122
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Table 6-2. Calculation of the Organism-Sediment Index based on sediment profile 

image parameters........................................................................................... 135

Table 6-3. Ten most abundant infaunal taxa from samples collected during the May 

1998 Survey 1 in the four sand resource areas (1, 2, 3, and 4) and two 

adjacent stations (R1 and R2) offshore North Carolina. .................................. 176

Table 6-4. Ten most abundant infaunal taxa from samples collected during the 

September 1998 Survey 2 in the four sand resource areas (1, 2, 3, and 4) 

and two adjacent stations (R1 and R2) offshore North Carolina...................... 177

Table 6-5. Summary of infaunal statistics by survey for sand resource areas (1, 2, 3, 

and 4) and adjacent stations (R1 and R2) offshore North Carolina. ................ 178

Table 6-6. Infaunal species groups resolved from inverse cluster analysis of all 

samples collected during the May 1998 Survey 1 and September 1998 

Survey 2 in the four sand resource areas and two adjacent stations 

offshore North Carolina................................................................................... 181

Table 6-7. Two-way table from normal (Station Groups X–E) and inverse (Species 

Groups 1-4a

) cluster analysis of infaunal samples collected during the 

May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand 

Resource Area 1 (A1) offshore North Carolina. Data are presented as 

total counts for individual taxa......................................................................... 183

Table 6-8. Two-way table from normal (Station Groups A–C) and inverse (Species 

Groups 1 and 2a

) cluster analysis of infaunal samples collected during the 

May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand 

Resource Area 2 (A2) offshore North Carolina. Data are presented as 

total counts for individual taxa......................................................................... 185

Table 6-9. Two-way table from normal (Station Groups A–C) and inverse (Species 

Groups 1-4a

) cluster analysis of infaunal samples collected during the 

May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand 

Resource Area 3 (A3) offshore North Carolina. Data are presented as 

total counts for individual taxa......................................................................... 187

Table 6-10. Two-way table from normal (Station Groups A–C) and inverse (Species 

Groups 1-3a) cluster analysis of infaunal samples collected during the 

May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand 

Resource Area 4 (A4) offshore North Carolina. Data are presented as 

total counts for individual taxa......................................................................... 188

Table 6-11. Epifauna and demersal fishes collected by mongoose trawl during the 

May 1998 survey of the four sand resource areas offshore North Carolina. .... 189

Table 6-12. Epifauna and demersal fishes collected by mongoose trawl during the 

September 1998 survey of the four sand resource areas offshore North 

Carolina. ......................................................................................................... 191

Table 7-1. Invertebrate and fish species for which Essential Fish Habitat (EFH) has 

been identified in the vicinity of the four sand resource areas offshore 

North Carolina. Species are listed in phylogenetic order. ............................... 221
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LIST OF ABBREVIATIONS 

μ

ADCP 

ASTM 

BVA 

CEQ 

CERC 

CETAP 

cm 

CSA 

deg 

DGPS 

EA 

EEZ 

EFH 

EIS 

FMP 

FRF 

ft 

g 

HAPC 

HMS 

Hz 

kg 

km 

l 

LPIL 

m 

MAB 

MAB-NURC 

MAFMC 

MARMAP 

MCM 

MCY 

mg/l 

MLLW 

MLW 

mm 

MMB 

MMS 

MSL 

MT 

MWL 

NAD 

NCGS 

NEFMC 

NEPA 

NGDC 

NGVD 

NMFS 

NOAA 

NOS 

OCS 

Micron 

Acoustic Doppler Current Profiler 

American Society for Testing Materials 

Barry Vittor & Associates, Inc. 

Council on Environmental Quality 

Coastal Engineering Research Center 

Cetacean and Turtle Assessment Program 

centimeter 

Continental Shelf Associates, Inc. 

degrees 

Differential Global Positioning System 

Environmental Assessment 

Exclusive Economic Zone 

Essential Fish Habitat 

Environmental Impact Statement 

Fishery Management Plan 

Field Research Facility 

feet 

gram 

Habitat Areas of Particular Concern 

Highly Migratory Species 

Hertz 

kilogram 

kilometers 

liter 

Lowest Practical Identification Level 

meter 

Mid-Atlantic Bight 

Mid-Atlantic Bight National Undersea Research Center 

Mid-Atlantic Fisheries Management Council 

Marine Monitoring, Assessment, and Prediction Program 

million cubic meters 

million cubic yards 

milligrams per liter 

Mean Lower Low Water 

Mean Low Water 

Millimeter 

Marsh-McBirney current meter 

Minerals Management Service 

Mean Sea Level 

metric tons 

Mean Water Level 

North American Datum 

North Carolina Geological Survey 

New England Fisheries Management Council 

National Environmental Policy Act 

National Geophysical Data Center 

National Geodetic Vertical Datum 

National Marine Fisheries Service 

National Oceanic and Atmospheric Administration 

National Ocean Service 

Outer Continental Shelf 
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LIST OF ABBREVIATIONS (CONTINUED)

OCSLA 

OSI 

Ppt 

RAC 

REF/DIF S 

RPD 

SAFMC 

sec 

SMS 

SOD 

SPI 

STWAVE 

USACE 

USC & GS 

USFWS 

USGS 

UTM 

WES 

WIS 

yd 

yr 

Outer Continental Shelf Lands Act 

Organism Sediment Index 

parts per thousand 

Roanoke-Albermarle Channel 

Refraction/Diffraction Model for Spectral Wave Conditions 

Redox Potential Discontinuity 

South Atlantic Fishery Management Council 

seconds 

Shoreline Modeling System 

Sediment Oxygen Demand 

Sediment Profile Image 

Steady-State Spectral Wave Model 

U.S. Army Corps of Engineers 

U.S. Coast and Geodetic Survey 

U.S. Fish and Wildlife Service 

U.S. Geological Survey 

Universal Transverse Mercator 

Waterways Experiment Station 

Wave Information Study 

yard 

year 
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1

1.0 INTRODUCTION 

 The Minerals Management Service (MMS), a bureau within the U.S. Department of the 

Interior, has responsibility for managing all mineral resources on the Federal Outer Continental 

Shelf (OCS), a zone that extends from three miles seaward of State coastline boundaries to 200 

miles offshore. Although most interest in this zone relates to oil and gas resources, the potential 

for exploitation of sand resources as a source for beach and barrier islands restoration has 

grown rapidly in the last several years as similar resources in State waters are being depleted or 

polluted. Extraction of sand resources in Federal waters may be preferred relative to State 

waters due to concerns over changes in physical and biological oceanographic conditions 

resulting from large quantities of material dredged from resource areas impacted by waves and 

currents. This has generated a need for technical information to ensure that offshore minerals 

are developed with due concern for potential environmental considerations. 

 Houston (1995, 2002) discusses the value of beaches and their maintenance through 

beach nourishment to America’s economy. Not only are beaches the dominant component of 

most coastal economies, but they also provide a certain level of protection against high winds 

and waves associated with storms. Although the earliest seaside resort along the Outer Banks 

(Nags Head) developed in the 1830s and was flourishing by the beginning of the Civil War 

(Dolan and Lins, 1986; Pilkey et al., 1998), it only has been since the 1940s that coastal 

development has grown steadily along the Outer Banks with the construction of bridges from the 

mainland and roads on the barrier islands. Miller (1993) stresses the importance of coastal and 

marine tourism as the world’s largest industry and its continual rise over the past 50 years. As 

such, beaches are key elements of coastal tourism because they represent the leading tourist 

destination. 

 Coastal community master plans are being developed and revised to address concerns 

associated with population growth, storm protection, recreation, waste disposal and facilities 

management, and zoning (Williams, 1992). Often, problems stemming from these issues are in 

direct conflict with natural coastal processes. Some of the more direct problems are related to 

coastal erosion and storm protection. The practice of replenishing beaches with sand from 

upland and nearshore sources as protection for community infrastructure has increased in direct 

relation to population growth. As coastal and nearshore borrow areas become depleted, and 

our knowledge of environmental effects of coastal sand mining develop, alternate sources of 

aggregate and beach fill must be evaluated for offshore sites to meet specific societal needs. In 

many cases, sand resource extraction from the OCS may prove environmentally preferable to 

nearshore borrow areas due to potential changes in waves and currents as large quantities of 

sand are dredged from the seafloor. 

 The MMS has significant responsibilities with respect to potential environmental impacts 

of sand and gravel mining. Existing regulations governing sand and gravel mining provide a 

framework for comprehensive environmental protection during operations. Specific 

requirements exist for evaluations and lease stipulations that include appropriate mitigation 

measures (Hammer et al., 1993; Woodworth-Lynas and Davis, 1996). Guidelines for protecting 

the environment stem from a wide variety of laws, including the OCS Lands Act (OCSLA), 

National Environmental Policy Act (NEPA), Endangered Species Act, Marine Mammals 

Protection Act, and others. Regulations require activities to be conducted in a manner that 

prevents or minimizes the likelihood of any occurrences that may cause damage to the 

environment. The MMS takes a case-by-case approach in conducting environmental analyses, 

as required by NEPA and the Council on Environmental Quality (CEQ) regulations. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

2

1.1 STUDY AREA AND BORROW SITE CHARACTERISTICS 

 The inshore portion of the continental shelf, seaward of the Federal-State OCS boundary 

and within the North Carolina Exclusive Economic Zone (EEZ), encompasses the project study 

area (Figure 1-1). Four potential sand resource areas were identified offshore Dare County, NC 

in Federal waters by the North Carolina Geological Survey (NCGS). The seaward limit of the 

study area is generally within about 15 km of the shoreline. Sand resource areas are located on 

the North Carolina OCS between the 10- and 20-m depth contours. The continental shelf 

surface within the study area contains many sand ridges formed during the Holocene 

transgression (Boss et al., 2002; see Section 2.0). Sand ridges 2- to 5-m high and 0.5- to 1.5-

km apart represent the primary sand resource targets of this study. For sand resource areas on 

the northern North Carolina continental shelf, average shoal relief is about 2 to 3 m. 

AREA 1

AREA 

2

AREA 3

AREA 4

75°44' 75°42' 75°40' 75°38' 75°36' 75°34' 75°32' 75°30' 75°28'

75°44' 75°42' 75°40' 75°38' 75°36' 75°34' 75°32' 75°30' 75°28'

35°46' 35°48' 35°50' 35°52' 35°54' 35°56' 35°58' 36° 36°2' 36°4' 36°6'

35°46' 35°48' 35°50' 35°52' 35°54' 35°56' 35°58' 36° 36°2' 36°4' 36°6'

Universal Transverse Mercator, Zone 18

North American Datum 1983

2500 0 2500 Meters

Sand Resource Area

Figure 1-1. Location diagram illustrating sand resource areas and Federal-State boundary offshore Dare 

County, NC. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

3

 Sand Resource Areas 1, 2, 3, and 4 contain borrow sites with the greatest potential for 

future use. Each area has specific geologic and geographic characteristics that make it viable 

as a sand resource for specific segments of coast. All sand resource areas are very similar 

geologically (medium sand size ridge deposits with relief of 2 m or greater and resource 

volumes of at least 1 million cubic meters [MCM]). However, sand from the eastern borrow site 

in Area 3 has a median grain size of 0.21 mm (fine sand), the smallest grain size for any of the 

potential resource areas. Regardless, all identified potential sand borrow sites are of great 

interest to the State, primarily due to their proximity to eroding beaches critical for storm 

protection and recreation. Physical processes (waves and currents) and biological habitat at 

borrow sites on the sand ridges illustrate relatively minor variability offshore North Carolina. 

However, habitat variability within resource areas varies widely depending on surface area 

boundaries and geographic position. Although these four potential sand resource areas were 

designated as ones with greatest potential, it is possible that sand could be dredged from 

intervening offshore areas. 

 The amount of dredging that occurs at any site is a function of Federal, State, and local 

needs for beach replenishment. There is no way of predicting the exact sand quantities needed 

in the foreseeable future, so a representative value for any given project was estimated based 

on discussions with State personnel and the MMS. Preliminary analysis of short-term impacts 

(storm and normal conditions) at specific sites along the coast landward of sand borrow sites 

indicates that about 1 MCM of sand could be needed for a given beach replenishment event. 

Long-term shoreline change data sets suggest that a replenishment interval of about 5 to 

10 years would be expected to maintain beaches. This does not consider the potential for 

multiple storm events impacting the coast over a short time interval, nor does it consider longer 

time intervals absent of destructive storm events. Instead, the estimate represents average 

change over decades that is a reasonable measure for coastal management applications. 

 Given the quantity of 1 MCM of sand per beach replenishment event, the surface area 

covered for evaluating potential environmental impacts is a function of average dredging depth. 

Two factors should be considered when establishing dredging practice and depth limits for 

proposed extraction scenarios. First, regional shelf sediment transport patterns should be 

evaluated to determine net transport directions and rates. It is more effective to dredge the 

leading edge of a migrating shoal, and infilling of dredged areas occurs more rapidly at these 

sites (Byrnes and Groat, 1991; Van Dolah et al., 1998). Second, shoal relief above the ambient 

shelf surface should be a determining factor controlling depth of dredging. Geologically, shoals 

form and migrate on top of the ambient shelf surface, indicating a link between fluid dynamics, 

sedimentology, and environmental evolution (Swift et al., 1976). As such, average shoal relief is 

a reasonable depth threshold for maintaining environmentally-consistent sand extraction 

procedures. 

 For sand resource areas within the study area, maximum shoal relief is on the order of 

5 m, and average shoal relief is about 2 to 3 m. Although modern beach replenishment practice 

varies depending on geographic location and level of funding for the North Carolina coast, it is 

reasonable to expect multiple replenishment events over the next 50 years from the designated 

sand resource areas. As such, one shoal deposit was selected from each resource area based 

on geological characteristics. A maximum excavation depth was determined for each specific 

site. In Area 1, a 2.40 x 106

 m2 borrow site was defined based on shoal morphology 

(Figure 1-2). Bathymetry data and geological samples indicate a maximum excavation depth of 

3 m (Boss and Hoffman, 2001), resulting in a 7.2 MCM extraction scenario; median grain 

diameter for the deposit is 0.41 mm (Table 1-1). The same procedure was used for selected 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

4

75°40'

75°40'

75°35'

75°35'

75°30'

75°30'

75°25'

75°25'

75°20'

75°20'

35°50'

35°50'

35°55'

35°55'

36°

36°

36°5'

36°5'

1

2

3 west

4

Bodie Island

Roanoke Island

Pea Island

Oregon Inlet

Nags 

Head

Kitty

Hawk

Atlantic Ocean

Platt 

Shoals

3 east

Depth (m NGVD)

2 to 0

0 to -2

-2 to -4

-4 to -6

-6 to -8

-8 to -10

-10 to -12

-12 to -14

-14 to -16

-16 to -18

-18 to -20

-20 to -25

-25 to -30

-30 to -35

Below -35

Bathymetric Surface

1970/75/96 

N

2000 0 2000 Meters

FEDERAL-STATE 

BOUNDARY

1980 SHORELINE

SAND 

RESOURCE AREA

POTENTIAL 

BORROW SITE

UNIVERSAL TRANSVERSE 

MERCATOR, ZONE 18

NAD 1983

Figure 1-2. Location diagram illustrating potential sand borrow sites relative to shelf morphology offshore 

Dare County, NC. 

borrow sites at the other three sand resource areas. The selected borrow site in Area 2 

encompassed 1.95 x 106

 m2 of seafloor to a depth of 3 m, resulting in 5.8 MCM of sand. Borrow 

site 3 west in Area 3 covers 0.83 x 106

 m2 of seafloor to a maximum excavation depth of 3 m. 

The borrow site contains 2.5 MCM of sand. For borrow site 3 east, surface area encompassed 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

5

0.70 x 106 m2. The maximum excavation depth was 2 m, resulting in 1.4 MCM of sand. The 

potential sand borrow site in Area 4 covers approximately 1.16 x 106 m2 of seafloor. For a 2-m 

excavation depth, the resulting sand volume is 2.3 MCM. The sand volume at each of these 

borrow sites is at least equal to the quantity of sand needed for any single expected 

replenishment event, so all analyses were used to estimate potential cumulative effects of 

multiple extraction scenarios. 

Table 1-1. Sand Resource Characteristics at Potential Borrow Sites in Resource Areas 

Offshore North Carolina. 

Borrow Site Sand Volume 

(MCM) 

Excavation 

Depth (m) D10 (mm) D50 (mm) D90 (mm) % Sand and Gravel 

1 7.2 3 0.85 0.41 0.26 99.7 

2 5.8 3 1.60 0.50 0.21 99.8 

3 east 1.4 2 0.42 0.21 0.13 99.7 

3 west 2.5 3 0.45 0.27 0.14 99.9 

4 2.3 2 0.83 0.36 0.19 100.0 

D10 = grain diameter above which 10% of the distribution is retained; D50 = median grain diameter; 

D90 = grain diameter above which 90% of the distribution is retained 

1.2 STUDY PURPOSE 

 The primary purpose of this study was to address environmental concerns associated with 

the potential for dredging sand from the OCS offshore Dare County, NC for beach 

replenishment and to document the findings in a technical report. The primary environmental 

concerns focused on biological and physical components of the environment. To this end, 

seven study objectives were identified: 

• Compile and analyze existing oceanographic literature and data sets to develop an 

understanding of environmental conditions offshore North Carolina and the 

ramifications of dredging operations at selected sand borrow sites; 

• Use physical processes data sets and wave climate simulations to predict wave 

transformation under natural conditions and in the presence of proposed dredging 

activities; 

• Determine existing coastal and nearshore sediment transport patterns using historical 

data sets, and predict future changes resulting from proposed sand dredging 

operations; 

• Design and conduct field data collection efforts for biological characterization to 

supplement existing information; 

• Analyze field data for biological characterization and address basic environmental 

concerns regarding potential sand dredging operations; 

• Evaluate the potential environmental effects of multiple dredging scenarios; and 

• Develop a document summarizing the information generated to assist with decisions 

concerning preparation of Environmental Assessments and Environmental Impact 

Statements to support negotiated agreements. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

6

In meeting these objectives, this document should provide invaluable information regarding 

environmental concerns examined relative to proposed future sand dredging in support of beach 

replenishment needs from offshore North Carolina. 

1.3 STUDY APPROACH 

 Physical and biological processes data were analyzed to assess the potential impacts of 

offshore dredging activities within the study area to minimize or preclude long-term adverse 

environmental impacts at potential borrow sites and along the coastline landward of resource 

areas. In addition, wave transformation and sediment transport numerical modeling were 

employed to simulate the physical environmental effects of proposed sand dredging operations 

to ensure that offshore sand resources are developed in an environmentally sound manner. 

 Five primary study elements were specified by the MMS in Task 1 (Data Collection and 

Analysis) of the Request for Proposal for addressing environmental concerns associated with 

offshore sand dredging for beach replenishment. They included: 

• Characterize benthic ecological conditions, using existing data sets and data collected 

from field work, in and around the proposed sand borrow areas; 

• Evaluate the benthic infauna present in the proposed borrow areas, and assess the 

potential effects of offshore sand dredging on these organisms, including an analysis of 

the potential rate and success of recolonization following dredging; 

• Develop a schedule of best and worst times for offshore sand dredging in relation to 

transitory pelagic species; 

• Evaluate the potential modifications to waves that propagate within the study area due 

to offshore sand dredging within the proposed sand resource areas; and 

• Evaluate the impact of offshore dredging and consequent beach replenishment in 

terms of potential alteration to sediment transport patterns, sedimentary environments, 

and impacts to local shoreline processes. 

 The first three study elements focus primarily on biology and associated ecological 

impacts relative to potential sand dredging operations. The final two elements concentrate on 

potential alterations to physical processes and sedimentary environments, as well as potential 

shoreline response to incident waves and currents resulting from dredging operations. The 

scientific approach used to address each of the study elements is presented below. The 

remaining study tasks (2-14) focused on document preparation and project management 

requirements. 

1.3.1 Ecological Conditions 

The goal of this study element was to characterize benthic ecological conditions in and 

around the four sand resource areas. This phase of the study primarily focused on field data 

collection efforts conducted in May and September 1998 (presented in detail in Section 6.0). 

Existing literature and data were compiled and summarized to characterize the ecological 

environment and to form the foundation upon which field surveys were designed. Biological 

field surveys were conducted to characterize infauna, epifauna, demersal fishes, sediment grain 

size, and water column parameters. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

7

1.3.2 Benthic Infaunal Evaluation 

 The goal of this study element was to assess the potential effects of offshore dredging on 

benthic infauna and analyze the potential rate and success of recolonization following cessation 

of dredging activities. Existing literature and data on dredging effects were searched and 

synthesized then combined with results from the biological field surveys to examine potential 

benthic effects and recolonization in the sand resource areas. Because monitoring surveys of 

actual sand mining operations were not to be conducted, the assessment of potential effects 

and recolonization was based only on field survey characterizations and existing literature. 

1.3.3 Project Scheduling 

 The goal of this study element was to determine the best and worst times for offshore 

dredging relative to pelagic species. Environmental windows are temporal constraints placed 

on dredging activities to protect biological resources from potentially detrimental effects 

(Dickerson et al., 1998). Existing information was collected and summarized concerning the 

seasonal occurrence of pelagic species and potential impacts from dredging. Project 

scheduling considerations for pelagic species then were analyzed based on this information. 

1.3.4 Wave Modifications 

The goal of this study element was to perform wave transformation numerical modeling to 

predict the potential for adverse modification of waves resulting from sand dredging operations. 

Changes in bathymetry in sand resource areas can cause wave energy focusing resulting in 

substantial alterations in sediment transport at the site of dredging operations, as well as along 

the shoreline landward of the borrow site. Because the purpose of dredging offshore sand from 

a specific site will be driven by the need for beach replenishment, it is critical to understand the 

impact of changing wave transformation patterns on shoreline response before potentially 

exacerbating a problem. Numerical comparisons of existing and post-dredging impacts 

provided a means of documenting modifications to waves as they crossed the four sand 

resource areas (detailed in Section 4.0). 

1.3.5 Sediment Transport Patterns 

 The goal of this study element was to predict changes in sediment transport patterns 

resulting from potential sand dredging operations using numerical information generated from 

wave transformation modeling, combined with existing offshore current data. Sediment 

transport rates were quantified for sand resource areas using an analytical approach, whereas 

transport rates at the shoreline were determined numerically using output from wave 

transformation numerical modeling (detailed in Section 5.0). 

 Historical shoreline and bathymetry data were compiled to document regional sediment 

transport patterns over a 100+ year time period. Net changes in sediment erosion and 

deposition on the shelf surface offshore North Carolina provided a direct method for identifying 

patterns of sediment transport and quantifying net rates of change throughout potential sand 

resource areas (detailed in Section 3.0). These data also were used to calibrate numerical 

results for direction and magnitude of sediment transport. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

8

1.4 DOCUMENT ORGANIZATION 

 This document was organized into nine major sections as follows: 

• Introduction 

• Environmental Setting 

• Regional Geomorphic Change 

• Wave Transformation Numerical Modeling and Nearshore Sediment Transport 

• Circulation and Offshore Sediment Transport Dynamics 

• Biological Field Surveys 

• Potential Effects 

• Conclusions 

• Literature Cited 

The sections are presented in a different order than the list of study elements in the RFP. 

Because benthic and pelagic biological characteristics are in part determined by spatially 

varying physical processes throughout the study area, physical processes analyses are 

summarized first. 

 In addition to the main document, appendices were prepared in support of many of the 

analyses presented in each section of the report. Furthermore, an Executive Summary, a 

Technical Summary, and a Non-Technical Summary will be prepared as separate documents to 

provide a brief description of the study for audiences ranging from researchers to non-technical 

people. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

9

2.0 ENVIRONMENTAL SETTING 

 The east coast of the U.S. is a trailing edge coast with gentle slopes and a broad 

continental shelf. The Outer Banks of North Carolina are barrier islands that front Pamlico, 

Albemarle, and Currituck Sounds (Figure 2-1) and protect the mainland of North Carolina south 

of Cape Lookout from Atlantic Ocean waves and currents. The North Carolina barrier island 

chain is 320 km long and consists of multiple barrier islands separated by 22 inlets (Figure 2-2). 

The present location of the barriers was established about 4,000 years ago when the rate of 

Holocene sea level rise decreased (Swift et al., 1972). The project area encompasses about 

40 km of Atlantic Ocean coast from Oregon Inlet (35°47’N) north to Kitty Hawk (36°05’N). 

Although the offshore Federal-State boundary marks the direct landward limit of the study area 

(Figure 1-1), the ultimate use of sand extracted from the OCS is for beach replenishment along 

Bodie Island beaches in Dare County (Figure 2-3). Consequently, a description of the 

environmental setting from the outer coast to the OCS is pertinent for addressing the overall 

study purpose. 

Figure 2-1. The northern coast Outer Banks of North Carolina (from Pilkey et al., 1998). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

10

Figure 2-2. Inlet locations along the Outer Banks (Cleary and Marden, 1999). 

Figure 2-3. Looking north from Oregon Inlet to southern Bodie Island. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

11

 Although Outer Banks beaches are transgressive and migrate westward at an average 

rate of about 1.4 m/yr (Inman and Dolan, 1989), estimates of shoreline recession vary with 

location (Figure 2-4). According to Inman and Dolan (1989), sea-level rise accounts for 

approximately 21% of shoreline recession; the remaining 79% is caused by washover, 

longshore transport, wind-blown transport, inlet deposits, and dredging. Maximum rates of net 

change are less than 5 m/yr, but the standard deviations of those rates are equal to or greater 

than the net rates. This indicates that there is large temporal uncertainty associated with these 

estimates. Variations in shoreline recession rates may be caused by underlying geology, and 

areas on top of old inlets are expected to be most vulnerable to erosion (Riggs et al., 1995). 

Figure 2-4. Shoreline change rate for the northern North Carolina barrier island coast (from Dolan and 

Lins, 1986). 

 The first settlers and vacationers arrived to the Outer Banks in 1663 and 1753, 

respectively (Dolan and Lins, 1986). Settlers typically lived near the sounds to avoid dangers 

associated with the ocean. It was not until after the Civil War that the ocean side began to be 

developed. In 1930, the first paved road was constructed on the ocean side of the barrier. The 

first of many attempts to stabilize the Outer Banks occurred in 1830 when Ocracoke Inlet was 

dredged (Dolan and Lins, 1986). Dredging continued for seven years until the channel began 

infilling as fast as it could be dredged. Efforts to preserve the Outer Banks began in the early 

twentieth century when the National Park Service and the Civilian Conservation Corps planted 

vegetation and constructed sand fences over 185 km of beach (Figure 2-5). In 1935, the Cape 

Hatteras National Seashore (121 km2

) was authorized. Later in 1966, 99 km2 were authorized 

for the Cape Lookout National Seashore. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

12

Figure 2-5. Sand fences constructed by the Civilian Conservation Corps along the Outer Banks in 1933 

(from Dolan and Lins, 1986). 

 The barrier beaches of North Carolina are vulnerable to shoreline erosion due to high 

wave energy, currents, and sea-level rise (Inman and Dolan, 1989). In fact, Inman and Dolan 

(1989) state that North Carolina has the highest rate of sea-level rise along the east coast of the 

United States (35 to 40 cm/century; Figure 2-6). For the immediate study area offshore Bodie 

Island, mean sea level (MSL) elevations measured at the U.S. Army Corps of Engineers 

(USACE) Field Research Facility (FRF) in Duck, NC indicate an 8.4 cm rise between January 

1986 and September 2002 (Figure 2-7), or 0.5 cm/year. 

Figure 2-6. Rates of sea level rise along the east coast of the United States (from Inman and Dolan, 

1989) based on Aubrey and Emery (1983). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

13

-0.1

0.0

0.1

0.2

0.3

0.4

M

e

an S

e

a

L

e

v

el m( )

1986 1988 1990 1992 1994 1996 1998 2000 2002

Year

Regression Line (Slope = 0.005)

NOS Water Level Station 8651370

USACE Field Research Facility Pier, Duck, NC

Figure 2-7. Trend for Mean Sea Level (MSL) elevations at Duck, NC (NOAA Station Number 8651370), 

1986 to 2002. 

2.1 OFFSHORE SEDIMENTARY ENVIRONMENT 

 Sand deposits from paleo-fluvial systems, modern inlet systems, and physical reworking 

of beach and shoreface environments by fluctuating sea level and modern processes have 

molded the bathymetry offshore Dare County (Swift et al., 1972; McBride and Moslow, 1991). 

Sea level variations during the Holocene created complex offshore topography, such as 

shoreface-attached and shoreface-detached sand ridges (Swift et al., 1972). Shoreface ridge 

origin on the northern North Carolina shelf and elsewhere has been debated for years (e.g., 

Swift et al., 1972; Stubblefield et al., 1984; McBride and Moslow, 1991; Snedden et al., 1994), 

with primary emphasis on modern shelf sediment transport processes and geologic controls 

associated with Holocene shoreline and inlet shoal deposits. Sand ridges offshore Bodie Island 

generally are oriented obliquely to the shoreline in a north-south direction. 

 Barrier island morphology of the Outer Banks is controlled by underlying geology (Hine et 

al., 1979; Riggs et al., 1995). The barriers are perched on pre-Holocene stratigraphic units 

(Riggs et al., 1995) that can roughly be divided into two geologic provinces at Cape Lookout. 

Islands north of Cape Lookout overlie Quaternary deposits, and barriers south of Cape Lookout 

are on Tertiary and Cretaceous deposits (Riggs et al., 1995). 

2.1.1 Seabed Morphology 

 The continental shelf varies in width from 120 km offshore Cape Henry to 40 km offshore 

Cape Hatteras (Inman and Dolan, 1989). The continental break is shallowest near Cape 

Hatteras, with depth increasing to the north (Shideler and Swift, 1972). The continental shelf 

north of Cape Hatteras has been deeply eroded by ancient river systems, such as the 

Albemarle, during periods of lower sea level (Swift et al., 1972). 

 Sand ridges along the inner and outer shelf that are obliquely oriented with respect to the 

shoreline are dominant features in the offshore environment (Swift et al., 1972). On the inner 

shelf, ridges have a spacing of about 2.1 km and a height of 2 to 10 m, whereas on the outer 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

14

shelf, ridge spacing is about 6 km (Swift et al., 1972). Outer shelf ridges are less complex and 

sub-parallel to the shelf break. Shoreface ridges may alter sediment transport processes on the 

shelf by guiding transport parallel to their crests (Swift et al., 1972). Large shoal features are 

asymmetrical, indicating longshore transport to the south. The origin of ridges offshore North 

Carolina is uncertain, but three hypotheses relating their formation to shoreline retreat have 

been proposed (Swift et al., 1972; McBride and Moslow, 1991): 

• Sand ridge development by detachment of shoreface during sea level rise; 

• Inlet associated shoal-retreat ridges; and 

• Cape-associated shoal-retreat ridges. 

 Sand ridge development by shoreface detachment may occur as sea level rise 

accelerates and barrier transgression increases (Swift et al., 1972). If the base of the shoreface 

is below the region of active wave energy, it may be stranded as the barrier migrates landward. 

Cape associated shoals will form when there is significant longshore transport, high wave 

energy, and a stabilizing headland from which the shoal develops (Swift et al., 1972). At the 

headland, longshore currents converge due to wave refraction around the headland, and littoral 

sediment will be deposited offshore. The seaward end of a cape-associated shoal often is 

segmented by spill over lobes that dissect the shoal during storms when water piles up on one 

side of the ridge. Diamond Shoals off Cape Hatteras is an example of a cape-associated ridge. 

 Platt Shoals, seaward of Nags Head and within the sand resource study area, and sand 

ridges off False Cape are inlet associated ridges. Historical inlets, such as Old Currituck Inlet, 

deposit sand as an ebb-tidal shoal. As the inlet migrates to the south and the barrier migrates 

landward, an elongate shoal develops at the orientation of the ebb-tidal delta retreat path 

(Figure 2-8; McBride and Moslow, 1991). When inlets close from excessive longshore sand 

transport, sand is reworked by Holocene processes into shoreface sand ridges. 

 Shoals on the North Carolina continental shelf north of Cape Hatteras up to 5 km long and 

several meters thick were characterized by Snyder (1993) with high-resolution, shallow seismic 

profiles (Figure 2-9). Similar features were identified by Hoffman (1998) and Boss and Hoffman 

(2001) in seismic and vibracore data collected by the NCGS (Figure 2-10). Snyder (1997) and 

Boss et al. (1999) documented small-scale bedforms on the shoreface between Oregon Inlet 

and Duck with sidescan sonar profiles. Boss et al. (1999) defined five principal seafloor types 

based on the acoustic character of the seafloor from sidescan sonar profiles: 1) a relatively 

weak acoustic return producing a generally uniform, light gray sonar record; 2) a moderate to 

strong acoustic return producing a medium-to-dark gray sonar record; 3) mixed weak and strong 

acoustic returns producing a sonar record with mixed light gray and medium-to-dark gray areas 

(termed “patchwork” pattern); 4) a relatively weak acoustic return with small areas of stronger 

(darker) reflections (termed “pock-marked” appearance); and 5) potential hard bottom or live 

bottom identified by the presence of small scarps. 

 Light gray sonograms (weak acoustic return) were found to be the most common acoustic 

signature observed by Boss et al. (1999) (Figure 2-11). Typically, these areas are associated 

with north-south trending bathymetric highs that average about 2.8 m thick. Sediment samples 

from cores for this seafloor type indicate that it is predominantly fine sand with zones of 

medium-to-coarse sand and shell near the base of shoals (Boss et al., 1999). Sonograms with 

medium-to-gray tones are the next most common type (Figure 2-12). A comparison of surface 

type relative to bathymetry and seismic profiles indicates that these deposits exist in troughs 

between bathymetric highs in the southern part of the study area. Surface texture is primarily 

medium-to-coarse sand with gravel-sized material and ripples with 1 to 1.5 m spacing (Boss and 

Hoffman, 2001). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

15

Figure 2-8. Migration of Old Currituck Inlet in relation to False Cape Shoals (from McBride and Moslow, 

1991). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

16

Figure 2-9. Seismic profiles in the vicinity of Platt Shoals (from Snyder, 1993). 

 The patchwork sonogram is a mixed weak and strong acoustic return that primarily is 

associated with slopes between bathymetric highs and lows (Figure 2-13). Boss et al. (1999) 

observed this seafloor type grading upslope to fine sand and downslope to medium-to-coarse 

sand and gravel. The location of this seafloor type suggests that it may result from fine sand 

transport downslope from ridges partially covering coarse sediment exposed in troughs. 

Pock-mark sonograms (Figure 2-14) also are caused by mixed acoustic signatures, but they are 

restricted to the northern portion of the study area. This seafloor type exists predominantly in 

areas that are relatively flat-lying at depths >20 m. Boss et al. (1999) state that it represents 

resistant stratum outcropping on the seafloor associated with sediment deposited within the 

Roanoke-Albermarle paleofluvial channel system. Vibracores from this area are predominantly 

mud with lenses and beds of fine sand (Boss and Hoffman, 2001). The final seafloor type may 

be associated with hard bottom deposits (Figure 2-15). Very few near-vertical features similar 

to hard bottom signatures reported from Onslow Bay (Riggs et al., 1998) were identified by Boss 

et al. (1999) within the study area. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

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Figure 2-10. Distribution of seismic and side scan sonar track lines (black lines) and vibracore locations 

(red-filled circles) offshore Dare County, NC (from Boss and Hoffman, 2001). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

18

Figure 2-11. Sonogram illustrating smooth, light gray (fine sand) surface (from Boss et al., 1999). 

Figure 2-12. Sonograms illustrating light gray and rippled medium-coarse sand (dark gray) surface (from 

Boss et al., 1999). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

19

 

Figure 2-13. Sonograms illustrating patchwork surface pattern; mix of fine and medium-coarse sand on 

slopes of ridges (from Boss et al., 1999). 

 

Figure 2-14. Sonograms illustrating pock marked surface pattern existing in the northern part of the study 

area associated with outcropping mud and sand lenses (from Boss et al., 1999). 

 Overall, the study area can be divided into two general regions based on surface texture. 

The southern area is characterized by north-south oriented sand ridges with troughs underlain 

by medium-to-coarse sand and gravel (Boss et al., 1999; Boss and Hoffman, 2001). The 

northern area contains relatively featureless bathymetry underlain by predominantly mud facies 

with fine sand beds and lenses. Throughout the study area, the areal coverage by hard bottom 

is relatively small (Boss et al., 1999). Figure 2-16 illustrates the distribution of sediment types 

relative to survey lines, illustrating a predominance of fine sand associated with ridges in the 

southern portion of the study area. 
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Figure 2-15. Sonogram illustrating scarps that occur occasionally on the shelf surface. Boss et al. (1999) 

interpreted these features as resistant material, probably cohesive mud, exposed on slopes 

(from Boss et al., 1999). 

2.1.2 Surface Sediment 

 Sediment offshore North Carolina has four principal sources: erosion of barriers, detrital 

sediment from rivers, biogenous remnants of marine organisms, and relict sediments from 

pre-Holocene environments (Inman and Dolan, 1989). Review of current literature suggests 

that relict sediment and erosion of the Outer Banks are the primary sources of sediment for 

beach and nearshore environments (Riggs et al., 1995). 

 Sediment distribution on the continental shelf is patchy, indicating that sediment transport 

is locally variable, possibly limited by the presence of large-scale sand ridges (Riggs et al., 

1995). Fine-grain sediment may be transported over long distances because it can be carried in 

suspension over the top of sand ridge crests (Riggs et al., 1995). North of Cape Hatteras, 

sediment contains abundant heavy minerals and quartz, and it is finer than sediment south of 

the Cape (Grosz et al., 1990). For the Roanoke-Albermarle paleofluvial channel system, 

estuarine mud crops out on the seafloor, and fluvial sands underlie the mud (Snyder, 1997b). 

South of Cape Hatteras, sediments are carbonate rich (Grosz et al., 1990). 

 Sediments farther offshore have been mapped with high-resolution sidescan sonar by the 

United States Geological Survey (USGS) (Figure 2-17). Areas of high backscatter (light areas) 

are sand and gravel, whereas areas of low backscatter (dark areas) are fine sand and silt. Platt 

Shoals (seaward of Nags Head) is a high backscatter area indicating that it is covered with sand 

and gravel. As stated above, sediment cores also have been collected outside the 3-mile 

Federal-State boundary for evaluating potential sand resources at and adjacent to Platt Shoals 

(Hoffman, 1998; Boss and Hoffman, 2001). As stated by Boss et al. (1999) and illustrated in 

Figure 2-16, fine sand surface texture predominates in the southern portion of the study area, 

and the percent of mud increases to the north. 
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Figure 2-16. Distribution of primary sediment types as determined from sonogram patterns in the study 

area (from Boss and Hoffman, 2001). 
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Figure 2-17. Sidescan sonar of the northern coast of North Carolina (from USGS, 2001). 

2.1.3 Subsurface Deposits 

 The underlying geology of the Outer Banks and adjacent offshore regions consist of 

heterogeneous, tabular lithostratigraphic units created by multiple cycles of sea level rise and 

fall (Riggs et al., 1995; Snyder, 1997a; Boss et al., 2002). During lowstands in sea level, fluvial 

systems are excavated in the exposed continental shelf, creating paleodrainage systems 

(Figure 2-18). As sea level rises, fluvial valleys are inundated and fluvial sedimentation moves 

landward many kilometers, creating shallow marine shelf environments dominated by fine to 

medium sand reworked from fluvial deposits (Riggs and Belknap, 1988; Riggs, 1996; Boss et 

al., 2002). This cycle of sea level rise and fall has created a complex subsurface off the coast of 

North Carolina (Shideler and Swift, 1972; Riggs et al., 1992). The influence of subsurface 

geology on the distribution and orientation of coastal deposits, including offshore ridge/shoal 

structures, has been described in detail by Riggs et al. (1995). 
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Figure 2-18. Paleodrainage system in coastal North Carolina (from Riggs et al., 1995). The area of 

greatest interest for this sand resources study is the Roanoke-Albermarle drainage system. 

 Shideler and Swift (1972) described offshore subsurface deposits between Cape Henry, 

Virginia, and Cape Hatteras, NC. They identified four subsurface units: Tertiary, pre-Wisconsin 

and early Wisconsin, late Wisconsin, and Holocene. Of these units, Holocene sediments are of 

greatest interest for defining sand resources offshore Dare County, NC. The Holocene 

transgressive sand sheet covering the modern sea floor is the youngest stratigraphic layer. 

These sands originate from eroding barrier islands. This unit truncates the upper portion of the 

late Wisconsin unit; the bottom reflector is 19 to 39 m below sea level (average 26 m) and 0 to 

12 m below the sea floor (average thickness is 5 m). The Holocene unit is close to horizontal, 

dipping only 0.34 m/km to the east (Shideler and Swift, 1972). This sand sheet has been 

reworked by Holocene processes to form modern sand ridge features offshore North Carolina. 

 A detailed geophysical analysis of shoreface geology was completed by Boss and 

Hoffman (2001) and Boss et al. (2002) for offshore waters from Oregon Inlet to Duck, NC using 

single-channel, high-resolution seismic reflection and sidescan sonar profiles (Figure 2-10). 

Five mapped units were identified within the upper 70 m of the shelf stratigraphic succession. 

All but the top unit gently dip to the east-southeast (0.4 to 0.6 m/km) and have tabular geometry. 

The uppermost stratigraphic unit is composed of fine-grained fluvial/estuarine sediment that 

back-filled incised streams during early Holocene sea-level rise. Three-dimensional mapping of 

the base of this stratigraphic unit indicates its origin from fluvial incision of the continental shelf 

during lowered sea level (Figure 2-19; Boss et al., 2002). This fluvial feature, referred to as the 
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Roanoke-Albermarle Channel (RAC), is the dominant subsurface feature off the northern coast 

of North Carolina (Riggs et al., 1995; Snyder, 1997a; Snyder, 1997b; Boss et al., 2002). The 

RAC is an ancestral branch of the Chesapeake Bay watershed formed during the Wisconsin Ice 

Age 14,000 to 18,000 years ago when sea level was about 91 m lower than present (Boss et al., 

2002). Figure 2-20 shows the cross-sectional extent of the channel deposit, where R1 is the 

bottom seismic reflector of the deposit. The maximum width of the channel is about 13 km 

(Boss et al., 2002). The lower boundary (R1) of this unit is 20 to 50 m below sea level. The 

RAC is mostly fluvial sand that would be ideal for beach fill. Unfortunately, this resource may be 

access limited because estuarine muds overlie the sand (Snyder, 1997a). 

 Seismic unit S2 encompasses sediment between reflector R2 and the seafloor (R0; see 

Figure 2-20). This unit includes the surface and subsurface expression of ridges in offshore 

sand resource areas defined by Hoffman (1998) and Boss and Hoffman (2001). Boss and 

Hoffman (2002) described the base of unit S2 as a widespread reflecting horizon that has been 

truncated by channel incision related to the formation of the RAC. Reflector R2 has relatively 

low relief with an overall slope of approximately 0.05 m/km to the east-southeast (Figure 2-21). 

Maximum thickness of unit S2 is about 17 m, and average thickness is approximately 6 m. Sand 

resources within this unit are most compatible with sand on Dare County beaches. 

Figure 2-19. Areal extent and depth to seismic reflector R1 (from Boss and Hoffman, 2001). 
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Figure 2-20. Portion of seismic reflection profile 080 near the intersection of line 132 illustrating the north 

(left) and south (right) margins of channel seismic facies S1 (from Boss et al., 2002). 

 

Figure 2-21. Structure contour map and isopach map for unit S2. The channel system defined by reflector 

R1 (shown in light blue) cuts through unit S2 (from Boss and Hoffman, 2001). 
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2.1.4 Sand Resources 

 Potential sand resource areas in Federal waters (outside the 3-mile limit) are described by 

Hoffman (1998), Boss et al. (1999), and Boss and Hoffman (2001). Four primary locations were 

identified as potential sand resource areas (see Figure 2-22). In addition, three distal sand 

ridges also were suggested as secondary sites. Resource areas were delineated using shallow 

seismic profiles and vibracore data. Secondary sites are not considered economically feasible 

because of distance from shore and difficulties associated with deep water dredging (Hoffman, 

1998). However, as dredging technology improves, these sites may provide an additional sand 

source to meet North Carolina beach replenishment needs. 

Figure 2-22. Diagram illustrating geological data and identified potential sand resource areas (from 

Hoffman, 1998). 
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 Most potential sand resource areas delineated by Hoffman (1998) and Boss and Hoffman 

(2001) are located south of the RAC. Area 1 is the exception, as it is partially truncated to the 

northwest by the RAC (Boss et al., 1999; 2002). Areas 2, 3, and 4 are associated with 

north-south oriented sand ridges (Boss et al., 1999); Area 2 encompasses the distal part of Platt 

Shoals. Ripple bedforms identified at each of the resource areas indicates that the surface 

sand is mobile. Sand resource areas were identified by Hoffman (1998) and Boss and Hoffman 

(2001) by delineating a transparent seismic facies throughout the study area. Figure 2-23 

illustrates three seismic cross-sections from Hoffman (1998) through the identified sand 

resource areas. 

Figure 2-23. Selected seismic profiles crossing potential sand resource targets offshore North Carolina 

(from Hoffman, 1998). See Figure 2-22 for location information. 
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 The seismic transparency of potential sand resource deposits may be attributed to 

homogeneous sediment where sufficient lithologic variation is lacking to produce seismic 

reflections or compacted sand at the surface of the deposit that might mask reflections in the 

upper portion of the unit (Hoffman, 1998). Vibracores obtained in the study area indicated that 

there were two major sediment types: a sandy lithofacies and a mud-prone lithofacies (Boss et 

al., 2002). The sand lithofacies (Type I) was divided into four subfacies: (IA) clean, laminated to 

massive quartz sand; (IB) coarse sand to gravel; (IC) normally graded, fining upward quartz 

sand; and (ID) reverse graded quartz sand (Boss et al., 2002). The mud-prone units (Type II) 

contained interbedded clayey sandy silt to silty sand (IIA) and mud-rich fine-to-medium sand 

(IIB). Mean grain size for Type I deposits was about 0.21 mm; Type II deposits averaged 

0.11 mm. Figure 2-24 provides a representative image of each of these subfacies. 

Figure 2-24. Illustration of the six representative lithofacies from offshore vibracores (see Figure 2-22 for 

core location; from Boss and Hoffman, 2001). 
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 Hoffman (1998) targeted shoreface sand ridges (N-S oriented topographic highs) as the 

areas having the greatest potential as sand resource sites. Four primary resource areas were 

identified to contain at least 77 million cubic yards (mcy) of fine-to-medium sand. Boss and 

Hoffman (2001) included vibracore analysis and bathymetry data for updating the seismic 

stratigraphic framework in the offshore sand resource areas. Sand volume estimates at each of 

the four resource areas were revised to reflect information derived from vibracores; that is, 

identified offshore shoals, about 3-m thick and seismically transparent, were recognized as 

uniform light-gray features on sidescan profiles that contain approximately 300 mcy of 

predominantly fine sand (Table 2-1). Additionally, areas of medium-to-coarse sand usually were 

confined to the bathymetric troughs. A few small hard-bottom areas were identified but their 

coverage throughout the study area is minimal (Boss et al., 1999). 

Table 2-1. Potential sand resource dimensions for the four primary sand targets (from Boss 

and Hoffman, 2001). 

Potential Sand Resource Area Area (million square yards) Volume (million cubic yards) 

Area 1 46.1 173.5 

Area 2 9.5 44.9 

Area 3 19.9 64.7 

Area 4 12.5 23.2 

Total 88.0 306.3 

2.2 GENERAL CIRCULATION 

 The Mid-Atlantic Bight is the curved section of the continental shelf off the eastern United 

States extending between Cape Cod and Cape Hatteras. It is bordered by Nantucket Shoals to 

the north and Diamond Shoals to the south. These geomorphic features play an important role 

in defining the hydraulic regime and regional sediment transport patterns. The continental shelf 

of the Mid-Atlantic Bight is approximately 100 km wide from Cape Cod to Cape Henry, 

narrowing to approximately 37 km at Cape Hatteras (Uchupi, 1965; Hunt et al., 1977). The 

depth of the shelf break decreases from about 150 m south of Georges Bank to about 50 m off 

Cape Hatteras. The North Carolina shoreline from Cape Henry to Oregon Inlet is oriented 

approximately 20° counter-clockwise of north (Birkemeier et al., 1981). Alongshore currents 

flow northward toward 340°, or southward toward 160°. 

 General circulation is directly related to regional atmospheric surface pressure, wind 

stress, and regional density patterns along and across the shelf. As early as 1916, there was 

extensive evidence of mean annual southwestward flow along the continental shelf of the 

Mid-Atlantic Bight in response to north-northeast winds (Bigelow, 1922; Beardsley and Boicourt, 

1981). At Cape Hatteras, south-moving shelf water turns seaward and is entrained by the 

north-flowing Gulf Stream (Bumpus, 1973). Based on measurements, mean annual current 

speeds typically range from 30 to 45 cm/s in the Mid-Atlantic Bight (Beardsley and Butman, 

1974). Along the mid-shelf, between Hudson Canyon and Cape Hatteras, surface drifter 

releases showed southerly flow from 20 to 32 cm/s (Bumpus, 1973). Near-bottom flows along 

the shelf average 6 cm/s to the southwest (Bumpus, 1973; Butman et al., 1979; Chuang et al., 

1979). Velocity magnitudes may be related to shelf width, increasing in speed to the south as 

the shelf narrows from Long Island to North Carolina (Hunt et al., 1977; Beardsley and Boicourt, 

1981). 

 Outflow from major estuaries plays an important role in surface salinity and current 

patterns in the Mid-Atlantic Bight (Bigelow, 1922; Beardsley and Boicourt, 1981). Low-salinity 
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waters of the Chesapeake Bay have been mapped as a narrow southward flowing band along 

the Virginia and North Carolina coasts, extending beyond Oregon Inlet at times of large bay 

outflows. Along-shelf low-salinity coastal currents were measured at speeds of 30 to 50 cm/s 

and decrease in magnitude with increasing distance from the coast (Boicourt, 1973). 

 The across-shelf flow was primarily density driven, evidenced by the increase in salinity 

with depth. The vertical salinity gradient created shelf circulation with a weak offshore 

component at the surface and a stronger onshore component near the bed. Sea-bed drifters on 

the middle and outer portion of the shelf of the Carolinas demonstrated northerly drift (offshore) 

at 1.5 to 2.5 cm/s (Boicourt, 1973; Bumpus, 1973). On the inner shelf and shoreface, bottom 

drift was onshore. 

2.2.1 Tidal Currents 

 Tides in the Mid-Atlantic Bight are dominated by the M2 semi-diurnal component. Cook 

(2000) and Cook and Shay (2002) reported that 90% of tidal water elevation level change and 

20 to 40% of horizontal current velocities are caused by the M2 component. A 12-year record of 

measurements at the Field Research Facility in Duck, NC shows an annual mean tide range of 

0.9 m (Leffler et al., 1992) and a mean spring tide range of at least 1.2 m (Birkemeier et al., 

1981). Three field experiments were conducted in Duck, NC over the period 1985 to 1988 

under fair weather, moderate-energy, and storm conditions (Wright et al., 1991). During fair 

weather periods, winds were light (less than 5 m/s), waves were small (less than 0.6 m), and 

currents on the inner shelf were dominated by a weak reversing tidal component of 

approximately 10 cm/s (Wright, 1993). Although wave-induced orbital velocities tend to 

dominate during moderate energy events, tidal flows contributed to bed shear stress during high 

tide. During storm conditions, wind-generated mean flows and wave orbital velocities dominate 

over tidal currents. Near-bottom, along-shelf tidal currents of up to 20 cm/s have been 

measured in a water depth of 8 m, but were not seen in the current meter record measured at 

17 m (Wright et al., 1991). In 1985 and 1987, cross-shore flow and sediment transport 

measured near Duck, NC tended to reverse with the tides. Weak offshore flow occurred at high 

tide, and stronger onshore flow prevailed during low tides (Wright et al., 1991). 

2.2.2 Wind-Generated Currents 

 There is a strong correlation between north-northeast winds and currents along the 

Mid-Atlantic Bight (Xu and Wright, 1998). The mean annual wind stress is generally oriented 

toward the east and southeast in the Mid-Atlantic Bight and strongly coherent with southerly 

along-shelf flow (Beardsley and Boicourt, 1981); regional wind patters control 88% of the 

alongshore currents (Cudaback and Largier, 2001). Although strong winds in any direction will 

produce large swell, only northeast winds tend to generate strong alongshore currents. During 

a typical northeaster in 1991(moderate storm), measured mean currents were approximately 23 

cm/s and orbital velocities were approximately 40 cm/s (Wright et al., 1994). Across-shelf flows 

during the northeast storm created seaward flow at 5 cm/s near the bed. Coupling between 

wind and water flow associated with northerly wind events parallel to isobaths of the Mid-Atlantic 

Bight create a coastward Ekman transport (Beardsley and Butman, 1974). North-northeast 

winds tend to enhance the coastal plume flowing out of Chesapeake Bay and favor seawarddirected, cross-shore, near-bottom flow (Xu and Wright, 1998). 

 Along-shelf flows were recorded by Lentz et al. (1999) for four months at locations 0.4, 

0.8, 1.4, 5.3, and 16 km offshore Duck, NC (Figure 2-25). The observations show that currents 
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Figure 2-25. Time series of the along-shelf wind stress (negative is equatorward); significant wave height 

in 8-m water depth; and the subtidal depth-averaged, along-shelf current at the five mooring 

sites. Offshore distances of mooring sites are in parentheses (from Lentz et al., 1999). 

were typically towards the south, and fastest currents were about 50 cm/s. On average, 

alongshore current velocities ranged from 4 to 10 cm/s, and cross-shore velocities were about 1 

to 2 cm/s (Lentz et al., 1999). 

 Wind stress in summer months tends to be relatively weak and directed toward the 

northeast (Beardsley and Boicourt, 1981). Summer southwest winds can result in up-shelf flow 

for 1 to 3 months. Upwelling is observed along much of the Mid-Atlantic Bight during July and 

August following southwesterly winds (Boicourt, 1973; Bumpus, 1973). Reversal in wind stress 

creates a vertical shear due to an offshore increase in the mean density field, such that the 

strongest up-shelf flow tends to be greatest near the bottom (Beardsley and Boicourt, 1981). 
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2.2.3 Density-Driven Currents 

 Buoyant water masses, originating from the Chesapeake Bay, migrate south along the 

coast to North Carolina every 3 to 8 days (Rennie et al., 1999; Cudaback and Largier, 2001). 

Buoyant water travels south at a rate of 0.3 to 0.7 cm/s (Rennie et al., 1999). During periods of 

northerly winds, less dense (less saline) water in the Chesapeake Bay is confined to the bay by 

wind stress. As winds subside or turn to the south, buoyant water is released from the bay and 

flows down the coast. Additionally, northerly winds result in upwelling along the coast of North 

Carolina, while southerly winds produce downwelling. During downwelling, less saline water 

from the Chesapeake will move south and sink with downwelling currents. This results in the 

halocline moving above the thermocline. During upwelling, the remaining Chesapeake Bay 

water mass moves offshore and the halocline and thermocline return to the same position. 

 Mean southward flow of the Mid-Atlantic Bight seems to be driven primarily by an 

alongshore pressure gradient imposed at the shelf break (Beardsley and Boicourt, 1981). The 

pressure field is established by horizontal shear between the Gulf Stream and the continental 

shelf forming a cyclonic gyre. The gyre flows to the south on the continental shelf and to the 

north in the Gulf Stream, beyond the shelf break. Calculations suggest that the alongshore 

pressure gradient (surface slope) will decrease to the south with a decrease in the width of the 

shelf (Bush and Kapferman, 1980; Beardsley and Boicourt, 1981). The southward geostrophic 

flow on the shelf yields velocities of 30 to 45 cm/s and net water excursions of 40 to 70 km 

(Beardsley and Butman, 1974). 

 Temperature-salinity diagrams can provide further support of seasonal circulation 

patterns. The water column on the shelf of the Mid-Atlantic Bight is stratified throughout much 

of the year (Boicourt, 1973; Hunt et al., 1977). During November and December, stratification 

breaks down as a result of cooling temperatures and turbulent mixing from winter storms. The 

water column remains stratified annually due to fresh water input from the Chesapeake Bay, 

and below 30 m due to warm high salinity water at the shelf break. However, as the width of the 

shelf narrows to the south, towards Oregon Inlet, stratified inner shelf water mixes with 

homogeneous mid-shelf waters (Boicourt, 1973). To the south of Cape Hatteras, frontal eddies 

occur in stratified waters as “tongues” of colder, less saline water on the shoreward side of the 

Gulf Stream (Glenn and Ebbesmeyer, 1994). Drifter observations show that Gulf Stream frontal 

eddies can propagate north of Cape Hatteras on the outer continental shelf, contributing to 

stratification of the water column. 

2.2.4 Waves and Wave-Generated Currents 

 Since 1980, wave measurements have been collected approximately 6 km offshore of the 

USACE FRF in Duck, NC in 18 m water depth. An annual average wave height of 1.0 m and 

period of 8.3 sec was estimated from a ten-year record (1980-1990) (Leffler et al., 1992). At this 

location, wave heights exceeded 3 m approximately 1.4% of the time and were classified as 

“severe storms”. During the Halloween storm of 1991, the largest and longest period waves (6 

m and 22 s) occurred after local winds had weakened and turned to the northwest (offshore) 

(Wright et al., 1994). Birkemeier et al. (1981) reported that wave heights and periods frequently 

exceed 4 m and 10 sec during extra-tropical storms from October to February. Wave directions 

were seasonally distributed, typically approaching from the north in the fall and winter and from 

the south in summer. Storm waves approach from the north approximately 70% of the time 

(Leffler et al., 1992). 

 Infragravity frequency (0.03-0.003 Hz) motions are correlated with wave groups and play 

an important secondary role in sediment transport on the shoreface off of Duck, NC (Wright et 

al., 1994). During calm periods, infragravity flows are weak (5 cm/s), but can increase to an 
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amplitude of 20 cm/s during northeast storm events. Although the total infragravity signal is 

comprised of group-forced long waves, edge waves, and leaky-mode standing waves, at least 

50% of the infragravity signal on the inner shelf of North Carolina originates from the surf zone 

(Okihiro et al., 1991; Guza, 1992). 

2.2.5 Nearshore Sediment Transport 

 Between Cape Henry and Cape Hatteras, Inman and Dolan (1989) state that longshore 

transport typically moves sediment from north to south, although there is spatial and temporal 

variation within this pattern (Figure 2-26). Extra-tropical storms are responsible for the most 

significant coastal erosion (Madsen et al., 1993; Wright and Madsen, 1994). Swell and storm 

conditions produce surface gravity waves that create sediment agitating bed stress (Wright, 

1993). Near bed wave orbital velocities of up to 100 cm/s have been measured during a 

northeast storm (Wright et al., 1991). During an extreme storm event, wave conditions, 

near-bottom orbital velocities, and suspended sediment concentrations measured in 13 m water 

depth indicated movable flat bed conditions and significant sediment transport potential 

(Madsen et al., 1993). Fluid-sediment interactions during the storm were sufficient to wash out 

ripples on the bed. However, near-bottom mean flows play the primary role in transporting 

sand across isobaths on the shoreface of the Mid-Atlantic Bight, distinguishing it from 

high-energy shoreface environments where the persistent swell creates a dominant oscillatory 

component (Wright et al., 1991). 

 Sediment transport processes on the shelf of the Mid-Atlantic Bight are storm dominated 

(Wright, 1993). Evidence suggests the net direction of sediment transport on the shelf is south 

between Long Island and Cape Hatteras (Swift et al., 1972). However, transverse shelf valleys 

partition the floor of the Mid-Atlantic Bight acting as sand traps and preventing sand from 

moving any appreciable distance (Hunt et al., 1977). Observations have shown a significant 

portion of the surficial sand sheet of the northern portion of the North Carolina shelf has been 

delivered to the shelf edge of Diamond Shoals, is mixed with silt settling out of the Gulf Stream, 

and subsequently is deposited in the Hatteras Canyon (Hunt et al., 1977). The valleys and 

canyons act as sinks to shelf sediments but sources to the offshore. A study by Horn et al. 

(1971) suggested that sediment of the abyssal plain west of the Mid-Atlantic Ridge were derived 

from the Hudson and Hatteras canyon systems. 

2.3 BIOLOGY 

2.3.1 Benthic Environment 

 The following subsections provide summaries of the existing literature concerning the 

benthic environment, including infauna (Section 2.3.1.1) and epifauna and demersal fishes 

(Section 2.3.1.2), in and around the four sand resource areas. This information, along with the 

assessment of ecological conditions from the biological field surveys (Section 6.0), provides the 

framework for the evaluation of potential effects from dredging on these organisms 

(Section 7.5). 

2.3.1.1 Infauna 

 Infaunal organisms collected during previous investigations of inner shelf waters offshore 

North Carolina predominantly consist of members of the major invertebrate groups that 

commonly inhabit sand bottom marine ecosystems, including crustaceans, echinoderms, 
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Figure 2-26. Variations in sand transport potential between Cape Henry, VA and Cape Hatteras, NC 

(from Inman and Dolan, 1989). 

mollusks, and polychaetous annelids. Infaunal assemblages that inhabit shelf waters offshore 

North Carolina resemble assemblages common to much of the Middle Atlantic Bight (Wigley 

and Theroux, 1981). Generally, inner shelf infaunal assemblages are numerically dominated by 

polychaetes in terms of abundance and numerically dominant taxa (Day et al., 1971; Weston, 

1988). Other conspicuous members of the coastal North Carolina infaunal community include 

amphipod crustaceans and bivalve mollusks. Infaunal taxa that inhabit inner shelf sand bottoms 

offshore North Carolina comprise assemblages that exhibit spatial and seasonal variability (Day 

et al., 1971; Boesch, 1972; Wigley and Theroux, 1981; Weston, 1988; MMS, 1989). 

 The distribution and abundance of infaunal populations that comprise North Carolina inner 

shelf communities are affected by abiotic environmental parameters. Spatially variable factors 

such as hydrology, water depth, and sediment type influence benthic assemblages and the 

extent of numerical dominance of those assemblages by various infaunal populations. 

 Cerame-Vivas and Gray (1966) found that north of Cape Hatteras, inner- and mid-shelf 

benthic invertebrate assemblages are representative of the Virginian Province, while Carolinian 

Province fauna predominate south of the Cape, with relatively few taxa ranging into both areas. 
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The authors further determined that the OCS offshore North Carolina was dominated by 

Caribbean Province epifauna. However, Day et al. (1971) found that these faunal zone 

delineations might not be as distinct when examining infaunal distribution. The area apparently 

does represent at least a marginal transition zone for some infaunal taxa. Gardiner (1976) 

reported that for motile polychaetes, the area offshore North Carolina represents the northern 

distributional limit for about 12% of species and the southern distributional limit for about 14% of 

species occurring in waters offshore North Carolina. 

 In a report based on 667 quantitative samples of benthic fauna collected from the Middle 

Atlantic Bight between 1956 and 1965, Wigley and Theroux (1981) summarized the relationship 

between water depth and infaunal abundance. The southern extent of the overall study region 

extended to Cape Hatteras and greatest infaunal densities in the region occurred at relatively 

shallow depths. With increasing water depth, abundance of each of the major taxonomic 

groups (e.g., bivalves) generally decreased, although not uniformly across taxonomic groups. 

For purposes of analysis, the Middle Atlantic Bight region was divided into subareas. In the 

Chesapeake Bight subarea in water depths less than 24 m, bivalves were numerically dominant 

(1,136 individuals/m2

), followed by amphipod crustaceans (198/m2) and annelids (183/m2). The 

relative paucity of annelids in the Wigley and Theroux (1981) study contrasts with other studies 

that found polychaetes to be the most conspicuous components of infaunal assemblages in 

inner shelf waters offshore North Carolina (Day et al., 1971; Weston, 1988). 

 Day et al. (1971) determined the distribution of infauna along a depth gradient from the 

beach zone to the edge of the continental shelf off Cape Lookout, NC. Infauna was sampled 

five times during a 1-year period using benthic grabs. Based on faunal composition, four 

subtidal zones were delineated at increasing depth intervals. The turbulent zone included the 

inner shelf between 3- and 20-m depths, and corresponds with the location of the sand resource 

areas that are the subject of the present study. The most abundant infaunal species within the 

turbulent zone included the amphipod Protohaustorius sp., the archiannelid Polygordius, and 

the polychaetes Bhawania (=Palaenotus) heteroseta, Goniadides carolinae, Macroclymene 

zonalis, and Magelona papillicornis. The most common taxa of the turbulent zone were best 

represented at the 20-m depth station (Day et al., 1971). 

 The effect of water depth on benthic assemblages may in some cases be defined more 

precisely as an effect of depth-related environmental factors, including parameters that vary with 

increasing depth, such as current regime, dissolved oxygen, sedimentary regime, and 

temperature. Surficial sediments tend to be well sorted at shallow depths, due primarily to the 

mixing of shelf waters by storms. In broad terms, inner shelf waters are less depositional in 

nature than outer shelf or slope waters due to a dynamic current regime, but shallow areas near 

an area affected by estuarine outflow may experience episodic deposition of fine materials, and 

thereby influence benthic community structure. Although existing descriptions of depth-related 

differences in benthic assemblages have encompassed geographically broad areas (Day et al., 

1971; Wigley and Theroux, 1981), local variability in bathymetric relief can result in habitat 

heterogeneity within an area of relatively minor depth differences. Trough features, especially 

those that are bathymetrically abrupt, can dissipate current flow along the substratum surface. 

Reduction of current flow can result in deposition of fine materials, including organic material. 

The presence of fine sediments and organics in bathymetric depressions can support benthic 

assemblages that are distinct from nearby areas without depressions (Boesch, 1972). 

 Certain infaunal populations are distributed in approximately equal numbers from shallow 

waters to the edge of the shelf (e.g., the polychaete Nephtys picta), while others occur mostly 

on the inner shelf (e.g., the polychaete M. papillicornis) or mid to outer shelf (e.g., the 

polychaete Scalibregma inflatum). Although there is a negative correlation between infaunal 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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36

abundance and water depth, it is unclear whether such faunal distributions are affected mostly 

by absolute water depth, or whether factors such as hydrology, sedimentary regime, and 

seasonality override any effects of sediment particle size and type on infaunal assemblages. 

 Previous sampling efforts in Atlantic shelf waters have demonstrated the importance of 

sediment type in determining infaunal population densities. Coarse-grained sediments 

generally support greatest numbers of infauna, while fine-grained sediments support the least 

(Wigley and Theroux, 1981; MMS, 1989). Wigley and Theroux (1981) summarized the 

relationship between sediment type and infaunal abundance of the Middle Atlantic Bight. 

Amphipods are found in all sedimentary habitats, though densities are greatest in sand-gravel 

and sand habitats. Generally, bivalve densities are greatest in sand-shell sediments and 

decrease with increasing sediment particle size, although shell fragment habitats can support 

moderately high bivalve numbers. Gravel bottoms support the lowest densities of bivalves. 

Polychaetes occur in all sediment types, although greatest abundances are found in sand and 

gravel bottoms and least in silt-clay habitats (Wigley and Theroux, 1981). 

 Sediment particle size also has a qualitative effect on the species composition of benthic 

assemblages (Sanders, 1958; Young and Rhoads, 1971; Pearce et al., 1981; Barry A. Vittor & 

Associates, Inc., 1985; Weston, 1988; Chang et al., 1992). Although many infaunal species 

inhabit a variety of sediment types (e.g., the polychaete S. bombyx), many infaunal taxa tend to 

predominate in specific sedimentary habitats. 

 In an investigation conducted offshore Cape Hatteras, Weston (1988) confirmed the 

findings of other studies in the Middle Atlantic Bight that found sedimentary regime a reliable 

predictor of the distribution of certain infaunal taxa. During the Weston (1988) study, grab 

samples were collected during four quarterly cruises at water depths ranging from 23 to 54 m. 

Cluster analysis was performed on the taxonomic data to delineate groups of stations that were 

similar with respect to infaunal composition. Four groups of stations (Groups 1 through 4) were 

delineated based on sample composition. Stations characterized by fine sand and relatively 

greater amounts of silt and clay (Group 1) were numerically dominated by the amphipod 

Ampelisca verrilli and the polychaetes Aglaophamus verrilli, Aricidea catherinae, Goniada 

littorea, Mediomastus californiensis, and Paraprionospio pinnata. The medium- to fine-grained 

sand community (Group 2) was numerically dominated by the archiannelid Polygordius and also 

supported high densities of the polychaetes Glycera oxycephala and Magelona cf. pettiboneae. 

Other investigations have found that great abundances of Polygordius commonly occur in inner 

shelf sand bottoms (Rabalais and Boesch, 1987), although Polygordius also has been observed 

to be common in coarser sediments, including shell hash (Barry A. Vittor & Associates, Inc., 

1985). The coarsest sediments in the Weston (1988) study were characterized by interstitial 

taxa occurring in relatively low numbers. Coarse sand and gravel areas (Group 3) offshore 

Cape Hatteras commonly yielded polychaetes such as Hemipodus roseus, Hesionura elongata, 

and Pionosyllis gesae, and surf clam (Spisula solidissima similis). The fourth group of stations 

was characterized by well-sorted, fine sand (Group 4) that was numerically dominated by the 

burrowing amphipods Bathyporeia parkeri, Protohaustorius cf. deichmannae, and Rhepoxynius 

epistomus. Overall, the percentage of fine sand and combined percentage of silt and clay were 

the parameters of greatest value in differentiating infaunal assemblages offshore Cape Hatteras 

(Weston, 1988). 

 Infaunal assemblages are composed of taxa that are adapted to particular sedimentary 

habitats through differences in behavioral, morphological, physiological, and reproductive 

characteristics. Feeding is one of the behavioral aspects most closely related to the 

sedimentary habitat (Sanders, 1958; Rhoads, 1974). In general, coarse sediments in high 

water current habitats, where organic particles are maintained in suspension in the water 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

37

column, favor the occurrence of suspension-feeding taxa that strain food particles from the 

water column. Coarse sediments also facilitate the feeding of carnivorous taxa that consume 

organisms occupying interstitial habitats (Fauchald and Jumars, 1979). At the other extreme, 

habitats with fine-textured sediments and little or no current are characterized by the deposition 

and accumulation of organic material, with these habitats supporting surface and subsurface 

deposit feeding taxa. In between these habitat extremes are a variety of habitat types that differ 

with respect to various combinations of sedimentary regime, depth, local bathymetry, and 

hydrological factors. These different habitats tend to support particular infaunal assemblages 

that tend to vary over time. 

2.3.1.2 Epifauna and Demersal Fishes 

 The benthic ecosystem of inner continental shelf waters offshore North Carolina is 

recognized as a zone of convergence of distinct faunal provinces. Based on the contents of 

qualitative dredge samples, Cerame-Vivas and Gray (1966) established that the inner 

continental shelf offshore North Carolina is divided into two faunal zones, with each of these 

characterized by epibenthic invertebrate assemblages corresponding to distinct biogeographic 

provinces. North of Cape Hatteras, inner- and mid-shelf sand bottom, epifaunal assemblages 

are representative of the Virginian Province, while Carolinian Province fauna predominate south 

of the Cape, with relatively few taxa ranging into both areas. Williams (1984) found that Cape 

Lookout may be a greater barrier to the northern extension of decapods than Cape Hatteras, 

and concluded that the region encompassing the two Capes represents a major barrier to about 

50% of southern decapod fauna that occur along the U.S. Atlantic coast. The demarcation of 

biogeographic provinces in the area of Cape Hatteras largely is a result of interaction between 

various ocean currents that determine the latitudinal extent of relatively cooler or warmer water 

temperatures, creating an ecological barrier for members of the respective province 

assemblages. 

 Many numerically dominant epifauna that inhabit inner shelf waters may be described 

more precisely as epibenthic, especially gastropods and decapods, although these taxa 

routinely are collected along with infauna using grab samplers. Certain epifaunal taxa, such as 

lady crab (Ovalipes ocellatus), commonly burrow deeply into sediments; adaptive behaviors of 

this type can complicate efforts to categorize such taxa into a specific, lifestyle-based, 

invertebrate group. Many bivalves are effectively sampled using either a trawl or grab method. 

Given this dilemma of ecological classification, however, the taxa discussed below commonly 

are collected in trawl samplers and, for the sake of comparison and consistency with previous 

investigations, herein are considered epifauna. 

 Other than certain asteroid echinoderms, most epifaunal taxa sampled by Cerame-Vivas 

and Gray (1966) north of Cape Hatteras also were found south of the Cape. Decapod 

crustaceans were especially prevalent in qualitative dredge samples during the study. Those 

decapods that were found along the entirety of the North Carolina inner shelf included Atlantic 

rock crab Cancer irroratus, blue crab Callinectes sapidus, lady crab O. ocellatus, hermit crab 

Pagurus longicarpus, rock shrimp Sicyonia breviostris, and sevenspine bay shrimp Crangon 

septemspinosa. Common inner shelf echinoderms that were found during the study included 

the asteroids Asterias forbesi, Astropecten americanus, and Luidia clathrata, and the sand 

dollar Mellita quinquiesperforata. Of the gastropods, Natica pusilla was the only species 

identified as characteristic of the Virginian Province (i.e., primarily occurring north of Cape 

Hatteras) (Cerame-Vivas and Gray, 1966). The most common epifauna collected by Day et al. 

(1971) in inner shelf waters offshore Cape Lookout included the sand dollar 

M. quinquiesperforata, hermit crabs (Pagurus spp.), and olive shells (Olivella spp.). Squids 

(Loligo spp.) commonly are collected in trawl hauls in the Middle Atlantic Bight. 
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 Certain epifauna are associated with particular sedimentary habitats (Wigley and Theroux, 

1981). Gastropod densities generally are greatest in areas of coarse sand and gravel. Coarse 

sediments are more suitable for locomotion by broad-footed benthic mollusks than are areas of 

fine sediments, which are relatively unstable. Decapods generally are found in areas of gravel 

and shell, although species such as C. septemspinosa tend to occur in areas of sand, while the 

crab C. irroratus inhabits a variety of sediment types. The sand dollars Echinarachnius parma

and M. quinquiesperforata most commonly are associated with sand habitats, while brittle stars 

are most common in silty sand, probably due to greater efficiency of burrowing in finer 

sediments. Sea stars tend to be distributed across a range of sediments, from shelly sand to silt 

habitats (Wigley and Theroux, 1981). 

 Demersal fishes inhabiting shelf waters offshore of northern North Carolina include a 

mixture of species with differing zoogeographic affinities, such as warm temperate, temperate, 

and boreal (Colvocoresses and Musick, 1984; Ross, 1985). This results in temporally dynamic 

assemblages with large seasonal changes in species presence and abundance. Depth and 

temperature are the most important large-scale environmental factors influencing distributions 

and abundances of demersal fishes in this region (Colvocoresses and Musick, 1984). In 

response to seasonally changing temperature, some species move north or south along the 

shelf, whereas others move onshore and offshore. The most abundant demersal species from 

the area north of Cape Hatteras include Atlantic croaker (Micropogonias undulatus), spot 

(Leiostomus xanthurus), weakfish (Cynoscion regalis), summer flounder (Paralichthys 

dentatus), and spiny dogfish (Squalus acanthius) (Ross, 1985). A large geographical area 

extending from Cape Hatteras, NC to Nova Scotia is considered wintering grounds for spiny 

dogfish and summer flounder (USACE, 2000). Other less abundant but frequently occurring 

species are Atlantic sturgeon (Acipenser oxyrhynchus), silver hake (Merluccius bilinearis), black 

sea bass (Centropristis striata), and scup (Stenotomus chrysops). Many species mentioned 

above are present and targeted by the winter trawl fishery in outer shelf waters from October to 

early April (Ross, 1985; North Carolina Division of Marine Fisheries, 1990). 

 Atlantic sturgeon is an anadromous species that spends a portion of its life history in North 

Carolina shelf waters, ascending rivers such as the Pamlico, Neuse, and Cape Fear to spawn 

during spring (Ross et al., 1988). Following several years in freshwater or estuarine habitats, 

young Atlantic sturgeons move into coastal and shelf waters to feed and grow until they reach 

maturity. Shortnose sturgeon (Acipenser brevirostris) is an endangered anadromous species 

but only occurs in inland waters throughout its life cycle and should not be affected by activities 

at the sand resource areas. Records of shortnose sturgeon in shelf or coastal waters are likely 

mistaken identifications of A. oxyrhynchus (Ross et al., 1988). 

 Much of the diet of Middle Atlantic fishes consists of other fishes; however, the diet of 

many of the most common demersal fishes consists of epibenthic and infaunal invertebrates 

(Grosslein, 1976). The affinity of certain demersal fishes for particular sediment types often is 

related to the types of prey items supported by those sediments (Rogers, 1977). Species such 

as butterfish, flounders, skates (Raja spp.), and spot are predominantly bottom feeders that 

consume infaunal and epibenthic crustaceans and polychaetes. Amphipods are known to be 

important in the diets of some demersal fishes, including Atlantic croaker, hakes, scup, skates, 

and windowpane. Certain demersal foragers therefore may be attracted to areas of sands, 

where crustaceans and polychaetes are most abundant (Wigley and Theroux, 1981). 

2.3.2 Pelagic Environment 

 The pelagic environment supports several living components of the nearshore shelf 

ecosystem. These include zooplankton, ichthyoplankton, and fishes. The available literature for 
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Implications of Sand Removal for Coastal and Beach Restoration 

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39

the Middle Atlantic Bight region supplied most of the information presented in this section. 

These studies included general information relevant to the North Carolina shelf as it is 

embedded within the larger region. As with other biotic components, the pelagic environment of 

this region is transitional due primarily to the confluence of several different water masses in the 

Cape Hatteras area. 

2.3.2.1 Zooplankton 

 Zooplankton form an essential link in the marine food web between the primary producers 

(phytoplankton and bacteria) and larger marine species such as fishes, birds, and marine 

mammals. They are relatively weak swimmers that drift with the currents. Zooplankton 

transport organic matter through the water column by their vertical migration and by the 

production of organically rich fecal pellets that sink to the seafloor. 

 Zooplankton can be functionally divided into holoplankton and meroplankton. 

Holoplankton spend their entire lives in the water column, whereas meroplankton occur as 

plankton only during certain stages (generally larval stages) of their life cycle. Many important 

commercial and recreational fish species have planktonic eggs and larvae. Holoplankton and 

non-fish meroplankton are discussed together in this zooplantkon section. Fish eggs and larvae 

are discussed separately in the ichthyoplankton section, which occurs after this section. 

 Major constituents of the zooplankton include gelatinous zooplankton, copepods, and 

chaetognaths. Other groups include amphipods, euphausiids, heteropods, cladocerans, 

polychaetes, and pteropods. In the Middle Atlantic Bight, zooplankton assemblages were 

studied by Sherman et al. (1983, 1984) and Kane (1997). These studies were based on 

collections in the Middle Atlantic Bight region conducted by the NMFS (e.g., Smith, 1988; Smith 

and Morse, 1988) primarily through the Marine Monitoring, Assessment and Prediction Program 

(MARMAP). Under this program, zooplankton samples have been collected at cross-shelf 

stations throughout the northeastern continental shelf from the Gulf of Maine to Cape Hatteras 

since the 1970’s. The Middle Atlantic Bight extending from Cape Cod to Cape Hatteras was a 

regional subarea within the MARMAP sampling scheme. Independently of MARMAP, Grant 

(1988, 1991) sampled zooplankton in the Middle Atlantic Bight offshore Virginia. 

 Zooplankton species composition in the Middle Atlantic Bight appears to be persistent 

over time. Comparisons of zooplankon samples collected over a wide spatial grid annually for 

5 years with older studies revealed that species composition and biomass in the northeastern 

Atlantic (including the Middle Atlantic Bight) have not changed appreciably in 70 years 

(Sherman et al., 1983, 1984). The seasonal pattern in zooplankton abundance and biomass is 

an annual low in winter to an autumn high (Sherman et al., 1983, 1984). This pattern was 

persistent within the Middle Atlantic Bight over the 5-year period (Sherman et al., 1983). 

Observed seasonal patterns were mostly driven by numerically dominant copepods (e.g., Kane, 

1997). Twelve copepod taxa (Calanus finmarchicus, Pseudocalanus sp., Centropages typicus, 

Metridia lucens, Temora longicornis, Centropages hamatus, Acartia tonsa, Acartia spp., Oithona

spp., Calanus spp., and Paracalanus parvus) represented 85% of the zooplankton abundance 

for the region (Sherman et al., 1983). Of these taxa, C. finmarchicus, P. minutus, and C. typicus

accounted for 75% of the zooplankton abundance. 

 Patterns of zooplankton abundance vary within and among the subregions of the 

northeastern Atlantic shelf. In the southern Middle Atlantic Bight, C. finmarchicus abundance is 

lower, and is replaced by P. minutus and C. typicus in late winter and early spring. From 

summer to fall the zooplankton abundance increased, mostly due to abundant cladocerans and 

C. typicus (Sherman et al., 1983). Members of the genus Centropages, other than C. typicus, 

were distributed variously based on water depth, temperature, and season (Grant, 1988). Two 
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40

species restricted to inshore areas (<50 m water depths) were C. hamatus and C. velificatus. 

The abundance of C. hamatus peaked during winter and spring, whereas C. velificatus was 

most abundant in summer and fall. 

2.3.2.2 Ichthyoplankton 

 The ichthyoplankton assemblage found in the Middle Atlantic Bight including northern 

North Carolina generally corresponds with the existing adult fish assemblage (Able and Fahay, 

1998). This adult fish assemblage consists of some resident species, but most are migrants 

from northern or southern waters. Northern species migrate south during winter months and 

southern species migrate north in the summer months. This pattern is seen in the occurrence of 

larval fishes in the Middle Atlantic Bight. Many of the transient species spawn while moving 

through Middle Atlantic Bight waters, thus contributing to the abundance and diversity of the 

local ichthyoplankton assemblages. Some larval taxa found in the Middle Atlantic Bight are 

spawned in more southerly waters of the South Atlantic Bight and transported northward by the 

Gulf Stream (Cowen et al., 1993). Because the spawning times of adults can be inferred from 

egg and larval occurrences, this information is given to augment information on temporal 

patterns of ichthyoplankton occurrence. Table 2-2 gives the spawning times and locations of 

important species from the region. 

 Long-term investigations of ichthyoplankton in the Middle Atlantic Bight region have been 

conducted by the NMFS (e.g., Smith, 1988; Smith and Morse, 1988) primarily through 

MARMAP. Summaries exist for various portions of the program (e.g., Sherman et al., 1984; 

Smith, 1988; Smith and Morse, 1988; Doyle et al., 1993). MARMAP collections from the central 

Middle Atlantic Bight were recently summarized by Able and Fahay (1998). Grothues and 

Cowen (1999) recently studied the relationship between larval fish assemblages and water 

masses in the vicinity of Cape Hatteras where the Middle Atlantic Bight and South Atlantic Bight 

meet. This study included cross-shelf transects near the four North Carolina sand resource 

areas. 

 More than 200 taxa of fish eggs and larvae were recorded from Middle Atlantic Bight 

waters by MARMAP (Smith and Morse, 1988). Fifty taxa represented most of the fish larvae 

collected from the entire northeastern Atlantic shelf (Doyle et al., 1993). Based on occurrence 

of larvae, Doyle et al. (1993) recognized a general Middle Atlantic Bight assemblage; however, 

when abundance was considered, spatial and seasonal sub-components appeared. For 

example, a southern Middle Atlantic Bight sub-component consisted of anchovies (Engraulidae), 

searobins (Triglidae), black sea bass (Centropristis striata), gobies (Gobiidae), and tonguefishes 

(Symphurus spp.). 

 A persistent seasonal cycle was documented for eggs and larvae in the Middle Atlantic 

Bight that reflects adults spawning times (Smith and Morse, 1988). Eggs occur in relatively low 

numbers during late winter, but by mid-April they were abundant and peak levels were reached 

in June. Numbers of larvae exhibited a similar seasonal pattern with a peak in summer. Each 

season’s samples were numerically dominated by different larval taxa (Sherman et al., 1984). 

In winter, sand lances exceeded all taxa in abundance representing over 90% of the numbers 

collected. In spring, the rank order of abundance was a lanternfish (Benthosema glaciale), 

Atlantic mackerel (Scomber scombrus), sand lance, windowpane, butterfish, and yellowtail 

flounder. In summer, smallmouth flounder, Gulf Stream flounder, anchovies, bluefish 

(Pomatomus saltatrix), butterfish, and searobins (Prionotus spp.) were numerically dominant. 

By fall, searobins, Atlantic croaker (Micropogonias undulatus), hakes (Urophycis sp.), Gulf 
41

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Table 2-2. Summary of spawning times and location of fishes in the central part of the 

Middle Atlantic Bight (Adapted from: Able and Fahay, 1998).

Species Spawning 

Time Spawning Location Egg Type 

Carcharhinidae 

Mustelus canis Sp Estuary/MAB Live 

Anguillidae 

Anguilla rostrata Sp SS Unknown 

Clupeidae 

Alosa aestivalis Sp FW Pelagic 

Brevoortia tyrannus Fa, Sp MAB/SAB Pelagic 

Clupea harengus Sp MAB Demersal 

Engraulidae 

Anchoa hepsetus Su MAB Pelagic 

A. mitchilli Su Estuary/MAB Pelagic 

Synodontidae 

Synodus foetens Unknown SAB Unknown 

Gadidae 

Pollachius virens Fa-Wi MAB Pelagic 

Phycidae 

Urophycis chuss Su MAB Pelagic 

U. regia Sp-Fa MAB Pelagic 

U. tenuis Sp MAB (Slope) Pelagic 

Ophidiidae 

Ophidion marginatum Su-Fa MAB Pelagic 

Syngnathidae 

Hippocampus erectus Sp-Su Estuary/MAB Live 

Triglidae 

Prionotus carolinus Su-Fa MAB (Estuary?) Pelagic 

P. evolans Su-Fa MAB (Estuary?) Pelagic 

Serranidae 

Centropristis striata Sp-Fa MAB Pelagic 

Pomatomidae 

Pomatomus saltatrix Sp-Su SAB/MAB Pelagic 

Carangidae 

Caranx hippos Unknown SAB Pelagic 

Lutjanidae 

Lutjanus griseus Su SAB Pelagic 

Sciaenidae 

Bairdiella chrysoura Su Unknown Pelagic 

Cynoscion regalis Sp-Su Estuary/MAB Pelagic 

Leiostomus xanthurus Wi MAB Pelagic 

Menticirrhus saxatilis Su MAB Pelagic 

Micropogonias undulatus Su-Fa MAB Pelagic 

Pogonias cromis Su MAB Pelagic 

Chaetodontidae 

Chaetodon ocellatus Unknown SAB Pelagic 

Mugilidae 

Mugil cephalus Wi SAB Pelagic 

M. curema Sp SAB Pelagic 

Sphyraenidae 

Sphyraena borealis Sp SAB Pelagic 

Labridae 

Tautoga onitis Sp-Fa Estuary/MAB Pelagic 

Tautogolabrus adspersus Sp-Fa MAB Pelagic 

Pholidae 

Pholis gunnellus Wi Estuary/MAB Demersal 

Uranoscopidae 

Astroscopus guttatus Su Estuary/MAB Unknown 

Stromateidae 

Peprilus triacanthus Sp-Su Estuary/MAB Pelagic 

Scophthalmidae 

Scophthalmus aquosus Sp,Fa Estuary/MAB Pelagic 

Paralichthyidae 

Etropus microstomus Sp-Fa MAB Pelagic 

Paralichthys dentatus Fa-Wi MAB Pelagic 

Pleuronectidae 

Pseudopleuronectes americanus Wi Estuary/MAB Demersal 

Spawning Time Spawning Location

Fa = Fall. FW = Fresh water. 

Sp = Spring. MAB = Middle Atlantic Bight. 

Su = Summer. SAB = South Atlantic Bight. 

Wi = Winter. SS = Sargasso Sea. 
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stream flounder, smallmouth flounder, and lefteye flounders (Bothidae) numerically dominated 

the collections. Able and Fahay (1998) summarized the species composition and monthly 

occurrence of larval fishes from MARMAP collections made in the central Middle Atlantic Bight 

which focused primarily on the New Jersey shelf but are relevant to the North Carolina sand 

resource areas (Table 2-3). 

 Several species mentioned above that are present as larvae and juveniles in the Middle 

Atlantic Bight actually were spawned in more southerly waters. Grothues and Cowen (1999) 

found that larvae of species spawned in waters south of Cape Hatteras often appear offshore in 

the Middle Atlantic Bight, transported to the area by the Gulf Stream. Many of these taxa, 

especially those of southern origin, do not survive in the Middle Atlantic Bight due to low water 

temperatures or other stressors. Two species spawned in southerly waters that do survive are 

bluefish and butterfish. Larvae and juveniles of these species enter offshore waters of the 

Middle Atlantic Bight and make their way into inshore waters where they spend their first year of 

life (Cowen et al., 1993; Rotunno and Cowen, 1997). These species appear to have adapted 

their cross-shelf migration to the complex circulation of the Middle Atlantic Bight. Species that 

are not adapted to early life in the Middle Atlantic Bight include razorfish (Xyrichthys) and some 

flatfishes (Bothus spp. and Syacium spp.). 

 Grothues and Cowan (1999) collected larvae from different water masses north and south 

of Cape Hatteras and found distinct assemblages associated with each water mass. 

Assemblages identified that were pertinent to the North Carolina sand resource areas were a 

Middle Atlantic Bight assemblage and a transitional assemblage consisting of species derived 

from both Middle Atlantic Bight and South Atlantic Bight regions. The Middle Atlantic Bight 

assemblage included larval yellowtail flounder (Limanda ferruginea), goosefish (Lophius 

americanus), and Atlantic mackerel. The transitional assemblage consisted of larval searobins, 

Etropus crossotus, herrings, anchovies, butterfish, gulfstream flounder, and lizardfishes. These 

assemblages were thought to persist through a combination of physical processes (currents and 

fronts) and larval behavior (Grothues and Cowen, 1999). 

2.3.2.3 Squids 

 Squids (cephalopods) display patchy distributions and periodic vertical and horizontal 

migrations. Water quality, currents, and temperature principally control the occurrence of 

squids, while food and population density affect movements within suitable water masses. 

 Two squid species are common in North Carolina shelf waters: the longfin squid (Loligo 

pealei) and the shortfin squid (Illex illecebrosus) (Lange and Sissenwine, 1980). These are the 

squids most likely to occur in or near the four sand resource areas. The longfin squid, a 

member of the family Loliginidae, occurs primarily in shelf and shelf edge waters from 

Newfoundland to the Gulf of Venezuela. Its distribution, determined by fishery independent 

sampling, is influenced by water temperature, depth, and time of day (Brodziak and 

Hendrickson, 1999). A general seasonal migratory pattern has been observed for the Middle 

Atlantic Bight population. Adults move offshore in fall and remain there until April, at which time 

adults and young migrate back into shelf waters for the summer (Lange and Sissenwine, 1980). 

Spawning reportedly occurs year-round with major peaks in spring (April and May) and fall 

(August and September). Longfin squid grow rapidly and live about one year (Lange and 

Sissenwine, 1980; Brodziak and Macy, 1996). This species represents an important fishery in 

the Middle Atlantic Bight with annual landings averaging 18,200 MT (Cadrin, 1998). 

Commercial fishing for longfin squid takes place from Cape Hatteras to Georges Bank. It is 
43

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Table 2-3. Ranking of the most abundant larval fishes collected in continental shelf waters in the central part of the Middle 

Atlantic Bight during the Marine Monitoring, Assessment and Prediction Program (MARMAP) surveys from 1977 to 

1987 (Adapted from: Able and Fahay, 1998). 

Taxon Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

Ammodytes spp. 1 1 1 1 2 -- -- -- -- -- -- 4 

Gadus morhua 2 3 2 3 7 -- -- -- -- -- -- 7 

Paralichthys dentatus 3 2 9 -- -- -- -- -- -- 5 2 1 

Brevoortia tyrannus 4 -- -- -- -- -- -- -- -- -- 5 5 

Merluccius bilinearis 5 9 -- -- -- 7 9 9 -- 6 4 2 

Maurolicus muelleri 6 -- -- -- -- -- -- -- -- -- -- 8 

Leiostomus xanthurus 7 -- -- -- -- -- -- -- -- -- -- -- 

Pollachius virens 8 4 7 -- -- -- -- -- -- -- -- -- 

Gobiidae 9 -- -- -- -- -- -- -- -- -- 8 -- 

Clupea harengus 10 -- -- -- -- -- -- -- -- -- -- -- 

Micropogonias undulatus 11 -- -- -- -- -- -- -- -- -- -- -- 

Pholis gunnellus -- 5 4 11 -- -- -- -- -- -- -- -- 

Myoxocephalus octodecemspinosus -- 6 3 10 -- -- -- -- -- -- -- -- 

Paralepididae -- 7 -- -- -- -- -- -- -- -- -- -- 

Anguilla rostrata -- 8 -- -- -- -- -- -- -- -- -- -- 

Notolepis rissoi -- 10 10 -- -- -- -- -- -- -- -- -- 

Pseudopleuronectes americanus -- -- 5 5 -- -- -- -- -- -- -- -- 

Myoxocephalus aenaeus -- -- 6 9 -- -- -- -- -- -- -- -- 

Cottidae -- -- 8 7 -- -- -- -- -- -- -- -- 

Benthosema glaciale -- -- -- 2 9 -- -- -- -- -- -- -- 

Limanda ferruginea -- -- -- 4 1 1 10 -- -- -- -- -- 

Liparis spp. -- -- -- 6 5 -- -- -- -- -- -- -- 

Melanogrammus aeglefinus -- -- -- 8 10 -- -- -- -- -- -- -- 

Scomber scombrus -- -- -- -- 3 3 -- -- -- -- -- -- 

Enchelyopus cimbrius -- -- -- -- 4 2 -- -- -- -- 10 -- 

Scophthalmus aquosus -- -- -- -- 6 6 11 -- -- 3 3 3 

Glyptocephalus cynoglossus -- -- -- -- 8 5 -- -- -- -- -- -- 

Lophius americanus -- -- -- -- -- 4 7 -- -- -- -- -- 

Tautogolabrus adspersus -- -- -- -- -- 8 3 7 -- -- -- -- 

Hippoglossina oblonga -- -- -- -- -- 9 1 2 4 8 -- -- 

Urophycis chuss -- -- -- -- -- 10 4 -- -- -- -- -- 

Peprilus triacanthus -- -- -- -- -- -- 2 1 8 -- -- -- 

Pomatomus saltatrix -- -- -- -- -- -- 5 6 -- -- -- -- 

Engraulidae -- -- -- -- -- -- 6 8 10 -- -- -- 

Citharichthys arctifrons -- -- -- -- -- -- 8 4 2 2 6 -- 

Urophycis spp. -- -- -- -- -- -- -- 3 1 -- -- -- 

Etropus microstomus -- -- -- -- -- -- -- 5 3 7 -- -- 

Prionotus carolinus -- -- -- -- -- -- -- 10 5 9 -- -- 

Ophidion marginatum -- -- -- -- -- -- -- -- 6 -- -- -- 

Lepophidium profundorum -- -- -- -- -- -- -- -- 7 -- 9 -- 

Centropristis striata -- -- -- -- -- -- -- -- 9 -- -- -- 

Ophidiidae -- -- -- -- -- -- -- -- -- 4 -- -- 

Bothus spp. -- -- -- -- -- -- -- -- -- 10 11 -- 

Urophycis regia -- -- -- -- -- -- -- -- -- 1 1 6 

Ceratoscopelus maderensis -- -- -- -- -- -- -- -- -- -- 7 -- 

Diaphus spp. -- -- -- -- -- -- -- -- -- -- -- 9 

Note: Larvae are ranked in the top 10 or 11 taxa per month according to numbers collected per 10 m2 of sea surface. Dashes indicate few or 

no collections of that taxon in that month. 
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caught with small meshed trawls, pound nets, and traps (Cadrin, 1998). Fishing effort tracks the 

seasonal distribution, with offshore (i.e., shelf edge) fishing taking place from October to March 

and inshore (i.e., middle and inner shelf) fishing taking place from April to September. 

 The shortfin squid belongs to the family Ommastrephidae, a family consisting entirely of 

oceanic species. It is distributed accordingly in oceanic and shelf edge waters from Geenland 

to Cape Hatteras (Lange and Sissenwine, 1980). It migrates into shallower waters (10 to 50 m) 

during summer months; in late fall it moves south and offshore in the area from Georges Bank 

to Cape Hatteras (Lange and Sissenwine, 1980). Spawning occurs from December to June in 

offshore waters. Most individuals die following spawning. The species lives up to one year 

(Hendrickson, 1998). In Middle Atlantic Bight waters, commercial trawl fisheries are 

concentrated in outer shelf waters from June to September when abundance peaks. The 1986 

to 1996 annual catch of shortfin squid averaged 12,800 MT (Hendrickson, 1998). Most 

commercial fishing is conducted in shelf edge waters with small-mesh trawls. 

2.3.2.4 Fishes 

 Pelagic fishes inhabiting shelf waters north of Cape Hatteras include Atlantic mackerel, 

bluefish, butterfish, striped bass (Morone saxatilis), and herrings such as alewife (Alosa 

psuedoharengus), American shad (Alosa sapidissima), Atlantic herring (Clupea harengus), 

Atlantic menhaden (Brevoortia tyrannus), and blueback herring (Alosa aestivalis). Numerous 

other pelagics occurring off northern North Carolina include striped and bay anchovies (Anchoa 

hepsetus and A. mitchilli, respectively), crevalle jack (Caranx hippos), king and Spanish 

mackerels (Scomberomorus cavalla and S. maculatus, respectively), and striped and white 

mullets (Mugil cephalus and M. curema, respectively) but are not mentioned further because of 

their lesser economic importance in this region. 

 All of these pelagic species form schools and migrate seasonally with peaks during 

various portions of the year. Most of these species are important to recreational and 

commercial fisheries. As with the demersal fishes, most pelagic species found in the Middle 

Atlantic Bight are transitory, originating in waters either to the north (Gulf of Maine or Georges 

Bank) or to the south (south of Cape Hatteras). Their occurrence in the Middle Atlantic Bight is 

generally a response to seasonal changes in water temperature that trigger southerly or 

northerly movements by species of southern or northern origin, respectively. 

 The Atlantic mackerel occurs in two spawning populations in the northwestern Atlantic: a 

northern population in the Gulf of St. Lawrence that spawns in June and July, and a southern 

population that spawns in the Middle Atlantic Bight during July and August (Overholtz, 1998b). 

In the Middle Atlantic Bight, the Atlantic mackerel spends winter months in offshore waters near 

the shelf edge; in spring, it migrates inshore and to the north. Spawning occurs during this 

migration in shelf waters. This species is sought by commercial and recreational fishers. 

Commercial fishing occurs primarily from January through May; recreational fishing occurs 

mostly from April to October (Overholtz, 1998b). Annual landings in the Middle Atlantic Bight 

averaged 14,840 MT from 1987 to 1996. 

 The bluefish is a migratory species occurring in inshore, coastal, and shelf waters. It 

migrates into the Middle Atlantic Bight during spring, and south or offshore during fall. The 

bluefish is an important fishery species. Early investigations held that the bluefish spawned 

during two discrete events: one in the South Atlantic Bight, and the other in the Middle Atlantic 

Bight. New evidence indicates that spawning is a continuous event, beginning during spring in 

South Atlantic Bight waters (Cowan et al., 1993; Smith et al., 1994). The bluefish spawns 

during mid-summer months in waters south of Cape Hatteras; however, young fishes recruit to 

inshore waters of the Middle Atlantic Bight coast including Long Island Sound (Nyman and 
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Conover, 1988). This species is important to commercial and recreational fisheries of the 

region. The 1994 to 1996 average annual commercial landings were 11,400 MT for the eastern 

U.S., and recreational landings for the Middle Atlantic Bight were 7,400 MT (Terceiro, 1998). 

Primary commercial gear for bluefish are otter trawl and gill net. 

 The Middle Atlantic Bight butterfish population migrates northward and inshore in summer. 

In winter months, the population moves southward and offshore. The butterfish spawns 

continuously from late January to at least July in the Middle Atlantic Bight (Rotunno and Cowen, 

1997). This species exhibits high natural mortality and is prey for many predatory species. It 

grows rapidly and reaches a maximum age of about 3 years (Rutunno and Cowen, 1997; 

Overholtz, 1998a). The current Middle Atlantic Bight fishery lands and average of 3,000 MT 

annually. Otter trawl is the principal gear used in the fishery. 

 The herring species exhibit two basic spawning patterns: the alewife, American shad, and 

blueback herring are anadromous, migrating from the sea into freshwater rivers to spawn, 

whereas Atlantic herring and Atlantic menhaden spawn in continental shelf waters. The alewife 

is found along the coast of eastern North America from the Gulf of St. Lawrence to South 

Carolina (Kocik, 1998a). During autumn, most of the population overwinters in waters near the 

edge of the continental shelf. In spring, the population moves into shelf waters throughout the 

region. Adults enter coastal rivers and migrate to fresh water to spawn during spring. The 

American shad is another anadromous species found in shelf waters during summer and fall 

(Kocik, 1998b). It moves up rivers to spawn during spring. Water temperature is the key 

environmental determinant of spawning in this species. Temperature may vary within a season, 

thus timing of the upstream migration may vary slightly from year to year. Alewife and American 

shad are important to commercial and recreational fisheries in the region. Commercial catches 

of alewife averaged about 500 MT/yr for the Middle Atlantic Bight since 1994 (Kocik, 1998a). 

American shad catches, mostly by gill net, have averaged 1,100 MT/yr since 1980 (Kocik, 

1998b). 

 Atlantic herring is most abundant in northern waters of the Gulf of Maine and Georges 

Bank. The Georges Bank stock overwinters in the New York Bight from December to April. 

Spawning occurs year-round with peaks in spring and fall. Adult females lay demersal eggs. 

Spawning probably does not occur offshore of North Carolina (Able and Fahay, 1998). The 

primary fisheries for this species occur north of New Jersey on Georges Bank and the Gulf of 

Maine. 

 The Atlantic menhaden occurs in shelf waters where it forms large schools. The 

population in the Middle Atlantic Bight migrates northward in summer and back south in fall to 

overwinter in warm waters. Spawning occurs offshore North Carolina during fall and spring. 

This species is not fished north of Virginia. 

Striped bass is an anadromous species, like alewife, shads, and Atlantic herring. Adult 

striped bass move upstream in spring to spawn and move back downstream and into shelf 

waters in late fall, where they remain through winter. Large striped bass populations along the 

U.S. east coast are associated with major river systems. The population found in the vicinity of 

the North Carolina sand resource areas is associated with the Roanoke River-Albemarle Sound 

watersheds (Manooch and Raver, 1984). Nearshore ocean waters from Cape Lookout, NC to 

Cape Charles, Virginia are wintering grounds for Atlantic coast striped bass populations 

(USACE, 2000). Overwintering grounds for striped bass include water depths in which the sand 

resources areas are located (Laney et al., 1999). 
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2.3.2.5 Sea Turtles 

 Five sea turtle species may occur in North Carolina coastal waters (Table 2-4). In 

approximate order of abundance, they are the loggerhead (Caretta caretta), Kemp’s ridley 

(Lepidochelys kempii), leatherback (Dermochelys coriacea), Atlantic green (Chelonia mydas), 

and hawksbill (Eretmochelys imbricata) turtles. The loggerhead is the most common turtle in 

North Carolina. The loggerhead is considered to be a regular nester in North Carolina in 

contrast to the other sea turtle species (USACE, 2000). Loggerhead and Kemp’s ridley turtles 

may be present year-round, whereas leatherback and Atlantic green turtles are not likely to be 

present during winter months. The North Carolina coast is a migratory corridor for juvenile and 

subadult loggerhead, Kemp’s ridley, leatherback, and green turtles, which move to northern 

waters during spring and return south of Cape Hatteras during fall (Keinath et al., 1996; MMS, 

1990). Hawksbills are the least common turtle in the area and are likely to occur only as 

occasional vagrants (Lee and Socci, 1989). 

 All five sea turtles are protected under the Endangered Species Act of 1973. 

Leatherbacks and Kemp's ridleys are endangered and loggerheads are threatened. Atlantic 

green sea turtles also are threatened, except for the Florida breeding population, which is 

endangered. Due to inability to distinguish between the latter two populations away from the 

nesting beach, Atlantic green sea turtles are considered endangered wherever they occur in 

U.S. waters (NMFS, 1996). 

Loggerhead Sea Turtle 

 The loggerhead sea turtle occurs throughout temperate and tropical waters of the Atlantic, 

Pacific, and Indian Oceans (Dodd, 1988). In the western North Atlantic, it is found in estuarine, 

coastal, and shelf waters from South America to Newfoundland. This is the only turtle that nests 

along the North Carolina coast. 

 Loggerhead turtles are present year-round in North Carolina waters, with peak abundance 

during spring and fall migrations (Lee and Socci, 1989; Keinath et al., 1996). Benthic immature 

turtles migrate northward from south of Cape Hatteras during spring, moving south again during 

fall (Keinath et al., 1996; Marine Turtle Expert Working Group, 1996a). 

 Four nesting subpopulations of loggerhead turtles have been identified (Marine Turtle 

Expert Working Group, 1996a). These are 1) the northern subpopulation, extending from North 

Carolina to northeastern Florida; 2) the south Florida subpopulation; 3) the Florida Panhandle 

subpopulation; and 4) the Yucatan subpopulation. Ninety percent of loggerhead nesting in the 

U.S. occurs in south Florida North Carolina is the northern extent of significant loggerhead 

nesting along the Atlantic coast (Frazier, 1995). The sea turtle nesting and hatching season in 

North Carolina is reported to extend from May 1 through November 15 of any year (USFWS as 

cited in USACE, 2000). Annual numbers of loggerhead nests in North Carolina during 1989 to 

1995 ranged from 459 to 1,021, with a mean of 729 nests annually (Marine Turtle Expert 

Working Group, 1996a). The highest nest densities are south of Cape Lookout, with a relatively 

low density of nests north of Cape Hatteras (MMS, 1990). 
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 After hatching, loggerheads swim offshore and begin a pelagic existence within 

Sargassum rafts, drifting in current gyres for several years (Marine Turtle Expert Working 

Group, 1996a). At approximately 40 to 60 cm carapace length, juveniles and subadults move 

into nearshore and estuarine areas, where they become benthic feeders for a decade or more 

prior to maturing and making reproductive migrations (Carr, 1987). 

 Loggerhead adults and subadults are generalist carnivores, feeding primarily on 

nearshore benthic crustaceans (particularly crabs) and mollusks (Dodd, 1988). These turtles 

generally feed in water depths of 15 m or less (NMFS, 1996), which would occur slightly inshore 

of the sand resource areas. 

Kemp’s Ridley Sea Turtle 

 The Kemp's ridley is the smallest and most endangered of the sea turtles. Its distribution 

extends from the Gulf of Mexico to Nova Scotia and Newfoundland (Marine Turtle Expert 

Working Group, 1996b). Adult turtles are found almost exclusively in the Gulf of Mexico, 

primarily in shallow coastal waters less than 50 m deep (Byles, 1988). 

 Kemp’s ridleys found along the North Carolina coast are juveniles and subadults that use 

shallow east coast waters as developmental habitat. They move northward along the coast with 

the Gulf Stream in spring to feed in productive, coastal waters between Georgia and New 

England (NMFS and USFWS, 1992). These migrants then move southward with the onset of 

cooler temperatures in late fall and winter. North Carolina is likely to represent the northernmost 

location for year-round residency of Kemp’s ridley juveniles and subadults (Schwartz, 1978; 

Lutcavage and Musick, 1985; Crouse, 1988). 

 Nesting of Kemp’s ridleys occurs almost entirely at Rancho Nuevo beach, Tamaulipas, 

Mexico, where 95% of the nests are laid along 60 km of beach (NMFS and USFWS, 1992; 

Weber, 1995). In the U.S., nesting occurs infrequently on Padre and Mustang Islands in south 

Texas and in a few other locations (Marine Turtle Expert Working Group, 1996b). 

Table 2-4. Sea turtle species potentially occurring in coastal North Carolina waters.

Species are listed in order of relative abundance.

Common and Scientific 

Names Statusa Life Stages 

Present Seasonal Presence Nesting Season b

Loggerhead sea turtle 

(Caretta caretta) 

T Adults, juveniles, 

subadults, 

hatchlings 

Year-round (most 

abundant during spring 

and fall migrations) 

April - 

September 

Kemp’s ridley sea turtle 

(Lepidochelys kempii) 

E Juveniles and 

subadults 

Year-round (most 

abundant during spring 

and fall migrations) 

(no nesting 

in area) 

Leatherback sea turtle 

(Dermochelys coriacea) 

E Adults, juveniles, 

subadults 

April-October (no nesting 

in area) 

Green sea turtle 

(Chelonia mydas) 

T/Ec Juveniles and 

subadults 

May-October (no nesting 

in area) 

Hawksbill sea turtle 

(Eretmochelys imbricata) 

E Juveniles and 

subadults 

Occasional vagrant (no nesting 

in area) 

a

 Status: E = endangered, T = threatened under the Endangered Species Act of 1973. 

b

 Loggerhead sea turtle nesting season as stated by MMS (1990). 

c

 Green sea turtles are listed as threatened except for Florida where breeding populations are listed as 

endangered. Due to inability to distinguish between the two populations away from the nesting beach, 

green sea turtles are considered endangered wherever they occur in U.S. waters. 
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 After emerging, Kemp’s ridley hatchlings swim offshore to inhabit Sargassum mats and 

drift lines associated with convergences, eddies, and rings. The hatchlings feed at the surface 

and are dispersed widely by Gulf and Atlantic surface currents. After reaching a size of about 

20 to 60 cm carapace length, juveniles enter shallow coastal waters and become benthic 

carnivores (Marine Turtle Expert Working Group, 1996b). This is the life stage that could be 

present in the project area. Kemp’s ridleys prefer crabs, but also occasionally eat mollusks, 

shrimps, dead fishes, and vegetation (Mortimer, 1982; Lutcavage and Musick, 1985; Shaver, 

1991; Burke et al., 1993; Werner and Landry, 1994). 

Leatherback Sea Turtle 

 The leatherback sea turtle is a circumglobal species that inhabits waters of the western 

Atlantic Ocean from Newfoundland to northern Argentina. The leatherback is the largest living 

turtle (Eckert, 1995), and with its unique deep-diving abilities (Eckert et al., 1986) and 

wide-ranging migrations, is considered the most pelagic of the sea turtles (Marquez, 1990). 

 Leatherback turtles occur in North Carolina waters primarily from April through October, 

with occasional sightings during winter (Lee and Palmer, 1981). Keinath et al. (1996) reported 

leatherback sightings during aerial surveys in May, July, August, October, and November. The 

species has been reported as occurring in shallow coastal waters but not usually near shore 

(Lee and Socci, 1989). Lee and Palmer (1981) reported its occurrence in waters from 16 to 

48 km offshore. 

 Leatherbacks nest on coarse-grained, high-energy beaches in tropical latitudes (Eckert, 

1995). Florida is the only location in the continental U.S. where significant leatherback nesting 

occurs. Very little is known of the pelagic distribution of hatchling and/or juvenile leatherback 

turtles. 

 Adult leatherbacks feed in the water column, primarily on cnidarians (medusae, 

siphonophores) and tunicates (salps, pyrosomas) (Eckert, 1995). The turtles are sometimes 

observed in association with jellyfishes, but actual feeding behavior has only occasionally been 

documented. Foraging has been observed at the surface, but also is likely to occur at depth 

(Eckert, 1995). 

Atlantic Green Sea Turtle 

 The Atlantic green sea turtle has a circumglobal distribution in tropical and subtropical 

waters. In the U.S., it occurs in Caribbean waters around the U.S. Virgin Islands and Puerto 

Rico, and along the mainland coast from Texas to Massachusetts. Adult green turtles are 

typically found in shallow tropical and subtropical waters, particularly in association with 

seagrass beds (NMFS and USFWS, 1991). 

 Most green sea turtles along the North Carolina coast are juveniles and subadults, 

because adults usually do not migrate from their preferred habitat (tropical/subtropical seagrass 

beds) except to nest. Juveniles and subadults may use shallow, coastal waters along the 

Atlantic coast as developmental habitat. These turtles have been sighted in North Carolina 

oceanic waters and sounds from May through October (Lee and Palmer, 1981; Lee and Socci, 

1989). 

 The primary nesting sites in U.S. Atlantic waters are high-energy beaches along the east 

coast of Florida, with additional sites in the U.S. Virgin Islands and Puerto Rico (NMFS and 

USFWS, 1991). A confirmed Atlantic green sea turtle nest has been recorded near the study 

area, but the species is not considered to be a regular nester (USACE, 2000). Hatchlings swim 

out to sea and enter a pelagic stage in Sargassum mats associated with convergence zones. 
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 Adult green turtles commonly feed on seagrasses, algae, and associated organisms, 

using reefs and rocky outcrops near seagrass beds for resting areas. The major feeding 

grounds in U.S. waters are located in Florida. In coastal waters, green turtles feed mainly on 

algae and the seagrass Zostera marina (Burke et al., 1992). Juveniles go through an 

omnivorous stage of 1 to 3 years (NMFS and USFWS, 1991). 

Hawksbill Sea Turtle 

 Hawksbill sea turtles (Eretmochelys imbricata) occur in tropical and subtropical seas of 

the Atlantic, Pacific, and Indian Oceans. In the western Atlantic, hawksbill turtles are generally 

found in clear tropical waters near coral reefs, including the Caribbean, the Bahamas, the 

Florida Keys, and the southwestern Gulf of Mexico. Hawksbills are rarely sighted north of 

Florida. They are the least frequently reported species in North Carolina coastal waters and are 

likely to be present only as occasional vagrants (Lee and Socci, 1989). A fishery for this 

species once existed in North Carolina (True, 1887), indicating that they were more abundant 

historically. 

 Nesting areas for hawksbills in the Atlantic are found in the U.S. Virgin Islands, Puerto 

Rico, and south Florida. Within the continental U.S., nesting beaches are restricted to the 

southeastern coast of Florida (i.e., Volusia through Dade Counties) and the Florida Keys 

(Monroe County), as noted by Meylan (1992) and the NMFS and USFWS (1993). No hawksbill 

nesting occurs near the project area. 

 Adult hawksbills typically are associated with coral reefs and similar hard bottom areas, 

where they forage on sponges. Hatchlings are pelagic, drifting with Sargassum rafts. Juveniles 

shift to a benthic foraging existence in shallow waters, progressively moving to deep waters as 

they grow and become capable of deeper dives for sponges. 

2.3.2.6 Marine Mammals 

 About 30 marine mammal species may occur off North Carolina (Table 2-5). However, 

only a few species are typically found in near-coastal waters. Marine mammals listed as 

endangered or threatened under the Endangered Species Act of 1973 are discussed first. 

A subsequent section covers non-listed species. All marine mammals are protected under the 

Marine Mammal Protection Act of 1972. 

Listed Species 

 Three species of endangered cetaceans are likely to occur in coastal North Carolina 

waters during at least some part of the year. They are the fin whale, Balaenoptera physalus; 

humpback whale, Megaptera novaeangliae; and northern right whale, Eubalaena glacialis. 

There is no “resident” population of any of these whales in the study region. Fin whales are 

likely to be present only during winter months. Humpback and northern right whales would be 

present only as transients during spring and fall migrations. One additional cetacean (the 

harbor porpoise, Phocoena phocoena), occurs seasonally in coastal waters and is a candidate 

for listing as a threatened species. One endangered sirenian, the Florida manatee (Trichechus 

manatus latirostris), may be present in coastal North Carolina waters during summer months. 

No critical habitat for listed marine mammals has been designated in or near the project area. 

 The project area is within the distributional range of three other endangered cetaceans 

(the blue whale, B. musculus; sei whale, B. borealis; and sperm whale, Physeter 

macrocephalus), but they are considered unlikely to be present. The sperm whale is a 

deepwater species (Winn, 1982; Roden, 1998), and blue and sei whales would not be expected 

to occur commonly off North Carolina (MMS, 1990; Waring et al., 1999). 
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Table 2-5. Species of marine mammals potentially occurring in North Carolina coastal 

waters. Key: (X) presence likely during at least some season; (o) presence 

possible but unlikely due to geographic range, preference for deeper waters, or 

uncommon occurrence. 

Scientific Name Common Name Statusa Presence 

ORDER CETACEA 

 SUBORDER MYSTICETI BALEEN WHALES 

 Family Balaenidae Right and Bowhead Whales 

 Eubalaena glacialis Northern right whale E, S X 

 Family Balaenopteridae Rorquals 

 Balaenoptera musculus Blue whale E, S o 

 Balaenoptera edeni Bryde's whale none o 

 Balaenoptera physalus Fin whale E, S X 

 Megaptera novaeangliae Humpback whale E, S X 

 Balaenoptera acutorostrata Minke whale none o 

 Balaenoptera borealis Sei whale E, S o 

SUBORDER ODONTOCETI TOOTHED WHALES 

 Family Physeteridae Sperm Whales 

 Kogia simus Dwarf sperm whale none o 

 Kogia breviceps Pygmy sperm whale none o 

 Physeter macrocephalus Sperm whale E, S o 

 Family Ziphiidae Beaked Whales 

 Mesoplodon densirostris Blainville's beaked whale S o 

 Ziphius cavirostris Cuvier's beaked whale S o 

 Mesoplodon europaeus Gervais' beaked whale S o 

 Mesoplodon mirus True's beaked whale S o 

 Family Delphinidae Dolphins 

 Stenella frontalis Atlantic spotted dolphin none X 

 Tursiops truncatus Bottlenose dolphin none X 

 Delphinus delphis Common dolphin S o 

 Pseudorca crassidens False killer whale none o 

 Lagenodelphis hosei Fraser's dolphin none o 

 Orcinus orca Killer whale none o 

 Stenella attenuata Pantropical spotted dolphin none X 

 Feresa attenuata Pygmy killer whale none o 

 Globicephala macrorhynchus Short-finned pilot whale S o 

 Globicephala melas Long-finned pilot whale S o 

 Grampus griseus Risso's dolphin none o 

 Steno bredanensis Rough-toothed dolphin none o 

 Stenella longirostris Spinner dolphin none o 

 Stenella coeruleoalba Striped dolphin none o 

 Family Phocoenidae Porpoises 

 Phocoena phocoena Harbor porpoise C,S o 

ORDER CARNIVORA 

SUBORDER PINNIPEDIA SEALS AND SEA LIONS 

 Phoca vitulina Harbor seal none o 

ORDER SIRENIA MANATEES AND DUGONGS

 Trichechus manatus latirostris West Indian manatee E o 

a Status: E = endangered and C = candidate for listing under the Endangered Species Act of 1973; 

S = strategic stock under the Marine Mammal Protection Act of 1972, as indicated by Waring et al. (1999).
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 Fin Whale (endangered). Fin whales range from the Arctic to the Greater Antilles, and 

animals off the eastern U.S. to Canada constitute a single stock (Donovan, 1991). They are 

among the largest and fastest baleen whales (Winn, 1982). This species occurs widely off New 

England and the Mid-Atlantic coast throughout the year, with concentrations from Cape Cod 

north in summer and from Cape Cod south in winter (Blaylock et al., 1995). They have been 

sighted off North Carolina only from January to early April, with most sightings during winter 

(Lee and Socci, 1989). Fin whales typically are usually found inshore of the continental shelf 

break and may occur near shore (Winn, 1982; MMS, 1990). This species feeds on krill, 

planktonic crustaceans, and schooling fishes such as herring and capelin. Mating and calving 

occurs from November to March. 

 Humpback Whale (endangered). Humpback whales range from the Arctic to the West 

Indies. During summer, there are at least five geographically distinct feeding aggregations in 

the northern Atlantic (Blaylock et al., 1995). During fall, humpbacks migrate south to the 

Caribbean where calving and breeding occurs from January to March (Blaylock et al., 1995). 

Aerial surveys during the Cetacean and Turtle Assessment Program (CETAP) detected only a 

few humpback whale sightings from New Jersey southward during any season (Winn, 1982). 

However, subsequently there have been numerous sightings and strandings off the Mid-Atlantic 

and southeastern U.S. coast, particularly during winter and spring (Swingle et al., 1993; Wiley et 

al., 1995). Most of the stranded animals were juveniles, suggesting that the area may be an 

important developmental habitat (Wiley et al., 1995). Humpbacks feed largely on euphausiids 

and small fishes such as herring, capelin, and sand lance, and their distribution has been largely 

correlated to prey species and abundance (Blaylock et al., 1995). Calving and breeding occurs 

in the Caribbean from January to March. Critical habitats have been identified in the western 

Gulf of Maine and the Great South Channel (Massachusetts).

 Northern Right Whale (endangered). Northern right whales range from Iceland to 

eastern Florida, primarily in coastal waters. This is the rarest of the world's baleen whales, with 

a North Atlantic population of between 325 and 350 individuals (Kraus et al., 1993). Coastal 

waters of the southeastern U.S. (off Georgia and northeastern Florida) are important wintering 

and calving grounds for northern right whales, while the waters around Cape Cod and Great 

South Channel are used for feeding, nursery, and mating during summer (Kraus et al., 1988; 

Schaeff et al., 1993). From June to September, most animals are found feeding north of Cape 

Cod. Southward migration occurs offshore from mid-October to early January (Kraus et al., 

1993). Migration northward along the North Carolina coast may begin as early as January, but 

occurs primarily during March and April (Lee and Socci, 1989; MMS, 1990). Designated critical 

habitat for the northern right whale includes portions of Cape Cod Bay and Stellwagen Bank and 

the Great South Channel (off Massachusetts) and waters adjacent to the coasts of Georgia and 

northeastern Florida. 

 Harbor Porpoise (candidate for threatened listing). The Gulf of Maine/Bay of Fundy 

stock of the harbor porpoise was proposed for threatened status in 1993 but the proposal was 

subsequently withdrawn by the NMFS in 1999. The stock remains on the “candidate” species 

list. Candidate species do not receive substantive or procedural protection under the 

Endangered Species Act. The candidate species list serves to notify the public that NMFS has 

concerns regarding these species that may warrant listing in the future, and it facilitates 

voluntary conservation efforts. 

 Harbor porpoises are found in cool temperate and subpolar waters of the Northern 

Hemisphere (Blaylock et al., 1995). Harbor porpoises were the most common odontocete 

species sighted on the continental shelf during CETAP (Winn, 1982). However, they were 

primarily concentrated in New England waters, well to the northeast of the North Carolina 
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coastline (Winn, 1982). As the name implies, harbor porpoises are typically found in shallow 

water, most often in bays and harbors, although they occasionally travel over deeper offshore 

waters (Jefferson et al., 1993). During summer, these animals are concentrated in Canada and 

the northern Gulf of Maine. During fall (October to December) and spring (April to June), they 

are widely distributed from Maine to North Carolina (Blaylock et al., 1995). Little is known of 

their distribution during winter (December through March). Harbor porpoises are believed to 

feed on pelagic schooling fishes such as herring and mackerel (Gaskin, 1992). 

 Florida Manatee (endangered). The West Indian manatee is one of the most 

endangered marine mammals in coastal waters of the U.S. In the southeastern U.S., manatees 

are limited primarily to Florida and Georgia. This group constitutes a separate subspecies 

called the Florida manatee (Trichechus manatus latirostris) that appears to be divided into at 

least two virtually separate populations – one centered along the Atlantic coast and the other on 

the Gulf coast of Florida (U.S. Fish and Wildlife Service [USFWS], 1996). Despite concerted 

research, it has not been possible to develop a reliable estimate of manatee abundance in 

Florida. The highest single-day count of manatees from an aerial survey is 1,856 animals in 

January 1992 (Ackerman, 1995). 

 During winter months, the manatee population confines itself to coastal waters of the 

southern half of peninsular Florida and to springs and warm water outfalls as far north as 

southeastern Georgia (USFWS, 1996). As water temperatures rise in spring, manatees 

disperse from winter aggregation areas. During summer, they may migrate as far north as 

coastal Virginia (USFWS, 1996). Manatees inhabit both salt and fresh water of sufficient depth 

(1.5 m to usually less than 6 m) throughout their range. They are usually found in canals, rivers, 

estuarine habitats, and saltwater bays, but on occasion have been observed as much as 

3.7 miles off the Florida coast (USFWS, 1996). 

 Based on their known distribution patterns, a few Florida manatees occasionally could be 

present in North Carolina waters during summer months. Lee and Socci (1989) report 

occurrences between late June and early November. However, because these animals tend to 

stay in shallow estuarine waters rather than the open ocean, they are considered unlikely to be 

present in the project area. 

 Critical habitat for this endangered species has been designated by the USFWS. All of 

the critical habitat areas are in peninsular Florida, predominantly along the southwest and 

southeast coasts (USFWS, 1996). 

Non-Listed Species 

 The most common non-listed marine mammal occurring in North Carolina coastal waters 

is the bottlenose dolphin (Tursiops truncatus), which may be present year-round (Winn, 1982; 

Kenney, 1990). Bottlenose dolphins in the western Atlantic range from Nova Scotia to 

Venezuela (Waring et al., 1999). This species is distributed worldwide in temperate and tropical 

inshore waters. Along the U.S. Atlantic coast, there are two distinct stocks: coastal and offshore 

(Duffield et al., 1983; Duffield, 1986; Mead and Potter, 1995). The two forms differ in 

distribution, morphometrics, parasite loads, prey, and DNA markers (Mead and Potter, 1995; 

Hoelzel et al., 1998). North of Cape Hatteras, the coastal stock is associated with water depths 

less than 25 m (Kenney, 1990). Therefore, bottlenose dolphins in the project area would most 

likely represent the coastal stock. Some portion of the coastal stock apparently resides south of 

Cape Hatteras during winter and migrates as far north as New Jersey during summer (Waring et 

al., 1999). The NMFS is currently studying Atlantic coastal bottlenose dolphins to determine 

whether they represent a single migratory stock or a series of multiple stocks (Waring et al., 

1999). Bottlenose dolphins feed on shrimps and fishes. Mating and calving occur from 
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February to May. The calving interval is 2 to 3 years. They are found in groups of up to several 

hundred individuals. 

 Also potentially occurring in shelf and coastal waters is the Atlantic spotted dolphin 

(Stenella frontalis). Atlantic spotted dolphins range from New Jersey to Venezuela, primarily in 

warm temperate and tropical waters. This species inhabits the continental shelf and slope, 

though southern populations occasionally come into shallow coastal waters (Waring et al., 

1999). Favored prey include herrings, anchovies, and carangid fishes. Mating has been 

observed in July, with calves born offshore. Atlantic spotted dolphins often occur in groups of 

up to 50 individuals. Stock structure in the western North Atlantic is unknown. 

 Two non-listed species of mysticetes may occur in North Carolina waters: Bryde’s whale 

(B. edeni), and minke whale (B. acutorostrata). Both are predominantly found in more northerly 

waters (Winn, 1982) and are infrequently sighted or stranded in North Carolina (MMS, 1990). 

 Non-listed odontocetes potentially occurring off the North Carolina coast but typically in 

deeper waters (along the shelf edge and beyond) include dwarf and pygmy sperm whales 

(Kogia simus and K. breviceps), common dolphin (Delphinus delphis), false killer whale 

(Pseudorca crassidens), pantropical spotted dolphin (Stenella attenuata), pygmy killer whale 

(Feresa attenuata), long-finned pilot whale (Globicephala melas), short-finned pilot whale 

(G. macrorhynchus), Risso’s dolphin or grampus (Grampus griseus), rough-toothed dolphin 

(Steno bredanensis), spinner dolphin (Stenella longirostris), and striped dolphin 

(Stenella coeruleoalba) (Winn, 1982; Roden, 1998; Waring et al., 1999). Though beaked 

whales (Mesoplodon spp. and Ziphius cavirostris) also may occur off the Mid-Atlantic, their 

distribution at sea is poorly known and they are believed to be principally deep, offshore 

species. Shelf species potentially occurring in the area but generally found in more northern 

waters include Fraser’s dolphin (Lagenodelphis hosei), and the previously discussed harbor 

porpoise. The killer whale (Orcinus orca) also may occur on the shelf or slope (Winn, 1982) but 

is considered uncommon or rare in U.S. waters (Blaylock et al., 1995). 

 One non-listed pinniped species, the harbor seal (Phoca vitulina), also may occur off the 

North Carolina coast. Harbor seals normally occur year-round in coastal waters of Canada and 

New England, moving south to winter (Blaylock et al., 1995). Occurrences off North Carolina 

would be most likely from November through May. 
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3.0 REGIONAL GEOMORPHIC CHANGE 

 Nearshore sediment transport processes influence the evolution of shelf sedimentary 

environments to varying degrees depending on temporal and spatial response scales. Although 

micro-scale processes, such as turbulence and individual wave orbital velocities, determine the 

magnitude and direction of individual grain motion, variations in micro-scale processes are 

considered noise at regional-scale and only contribute to coastal response in an average sense. 

By definition, regional-scale geomorphic change refers to the evolution of depositional 

environments for large coastal stretches (10 km or greater) over extended time periods 

(decades or greater) (Larson and Kraus, 1995). An underlying premise for modeling long-term 

morphologic change is that a state of dynamic equilibrium is reached as a final stage of coastal 

evolution. However, interaction between the scale of response and forces causing change may 

result in a net sediment deficit or surplus within a system, creating disequilibrium. This process 

defines the evolution of coastal depositional systems. 

 Topographic and hydrographic surveys of coastal and nearshore morphology provide a 

direct source of data for quantifying regional geomorphology and change. Historically, 

hydrographic data have been collected in conjunction with regional shoreline position surveys 

by the U.S. Coast and Geodetic Survey (USC&GS); currently Coast and Geodetic Survey of the 

National Ocean Service [NOS], National Oceanic and Atmospheric Administration [NOAA]). 

Comparison of digital bathymetric data for the same region but different time periods provides a 

method for calculating net sediment movements into (accretion) and out of (erosion) an area of 

study. Coastal scientists, engineers, and planners often use this information for estimating the 

magnitude and direction of sediment transport, monitoring engineering modifications to a beach, 

examining geomorphic variations in the coastal zone, establishing coastal erosion setback lines, 

and verifying shoreline change numerical models. The purpose of this portion of the study is to 

document patterns of geomorphic change throughout the sand resource areas and quantify the 

magnitude and direction of net sediment transport over the past 100 to 120 years. These data, 

in combination with wave and current measurements and model output, provide a temporally 

integrated technique for evaluating the potential physical impacts of offshore sand mining on 

sediment transport dynamics. 

3.1 SHORELINE POSITION CHANGE 

 Creation of an accurate map is always a complex surveying and cartography task, but the 

influence of coastal processes, relative sea level, sediment source, climate, and human 

activities make shoreline mapping especially difficult. In this study, shoreline surveys are used 

to define landward boundaries for bathymetric surfaces and to document net shoreline 

movements between specified time periods. Consequently, net change results can be 

compared with wave model output and nearshore sediment transport simulations to evaluate 

cause and effect. Results integration provides a direct method of documenting potential 

environmental impacts related to sand mining on the OCS. 

3.1.1 Previous Studies 

 Beaches along the Outer Banks of North Carolina consist primarily of sand, shell, and 

gravel reworked from Tertiary and Quaternary Coastal Plain sediment (Riggs et al., 1995; Pilkey 

et al., 1998). Nearshore sediment from Cape Hatteras north to Virginia is predominantly fine 

gray sand (Figure 3-1; Inman and Dolan, 1989); however, sections of beach between Nags 

Head and the False Cape contain high concentrations of non-carbonate gravel (Pilkey et al., 

 
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Figure 3-1. Sediment type, shoreline change, and direction of net littoral drift along the Outer Banks of 

North Carolina (from Inman and Dolan, 1989). 

1998). Gravel deposits are associated with ancient river channels that underlie the barrier 

beaches and outcrop on the shoreface. These deposits are located outside the immediate 

study area (Kitty Hawk to Oregon Inlet). 

 Historical shorelines for the North Carolina coast north of Cape Hatteras were mapped by 

Everts et al. (1983) as part of a cooperative analysis of shoreline change between the USACE 

and the NOS. The primary benefit of these data was to document shoreline response since the 

mid-1800s to natural processes and engineering activities (e.g., beach nourishment, jetty and 

groin placement). Langfelder (1970) and Dolan et al. (1979) extracted shorelines from aerial 

photography dating from 1945 to document short-term trends in beach response (Figure 3-1). 

The average rate of shoreline retreat between False Cape and Oregon Inlet was determined to 
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be about 1.4 m/yr. However, the beaches adjacent to Oregon Inlet illustrate retreat rates as 

high as 5 m/yr (Inman and Dolan, 1989). Everts et al. (1983) documented shoreline changes 

between 1849 and 1980 using historical maps and aerial photography. Net recession rates 

between Kitty Hawk and Oregon Inlet increased from 0 to 3 m/yr, respectively, illustrating the 

influence of inlet processes on shoreline response (Figure 3-2). Overall, the dominant direction 

of transport at the inlet was north to south, resulting in southward growth of Bodie Island at a 

rate of about 23 m/yr (Figure 3-3; Dolan and Smith, 2003). Between 1991 and 2001, southward 

migration of Bodie Island increased to a rate of about 60 m/yr (USACE, 2002), resulting in a net 

migration rate of about 27 m/yr since 1849. 

 More recently, Overton et al. (1999) compiled shoreline positions from maps and aerial 

photography for the period 1940 to 1995 for Dare County beaches. Figure 3-4 illustrates the 

trend of long-term change between Southern Shores and Nags Head. Approximately 35% of 

the coast was accreting and 65% was eroding. The largest recession rate was about 3.5 m/yr 

near Nags Head. 

3.1.2 Shoreline Position Data Base 

 For the present study, six outer coast shoreline surveys, conducted by the USC&GS 

(predecessor to NOS) in 1849/51, 1915/16, 1949, 1962, 1975, and 1980 (Table 3-1), were used 

to quantify historical shoreline change. The 1849/51 and 1915/16 were completed as field 

surveys using standard planetable techniques, whereas the final four shoreline surveys were 

compiled from interpreted aerial photography. 

 When determining shoreline position change, all data contain inherent uncertainties 

associated with field and laboratory compilation procedures. These potential errors should be 

quantified to gage the significance of measurements used for engineering/research applications 

and management decisions. Table 3-2 summarizes uncertainty estimates for shoreline data 

sets used in this study. Because these individual potential errors are considered standard 

deviations, root-mean-square uncertainties are calculated as a realistic assessment of 

combined potential error. 

 Positional uncertainties for each shoreline can be calculated using the information in 

Table 3-2; however, change analysis requires comparing two shorelines from the same 

geographic area but different time periods. Table 3-3 is a summary of potential errors 

associated with change analyses computed for specific time intervals. As expected, maximum 

positional uncertainties are aligned with the oldest shorelines (1849/51 and 1915/16) at smallest 

scale (1:20,000 and 1:40,000), but most change estimates for the study area document 

shoreline advance or retreat greater than these values. 

3.1.3 Historical Change Trends 

 Regional change analyses provided a without-project assessment of shoreline response 

for comparison with predicted changes in wave-energy focusing at the shoreline resulting from 

potential offshore sand dredging activities. It differs from previous analyses in that continuous 

measurements of shoreline change are provided at 50-m alongshore intervals for the period 

1849/51 to 1980 (see Appendix A). As such, model results (wave and sediment transport) at 

discrete intervals along the coast can be compared with historical data to develop 

process/response relationships for evaluating potential impacts. The following discussion 

focuses on incremental changes in shoreline response (1849/51 to 1915/16, 1915/16 to 1949, 

1949 to 1980) relative to net, long-term trends (1849/51 to 1980). 
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Figure 3-2. Shoreline change rates and standard deviations of position change from about 1850 to 1980 

between Cape Henry, VA and Cape Hatteras, NC (from Everts et al., 1983). 
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Figure 3-3. Shoreline changes adjacent to Oregon Inlet, NC for five surveys between 1852 and 1980 

(from Everts et al., 1983) 
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Figure 3-4. Erosion rate analysis for the period 1940 to 1992/95 for Dare County, NC (from Overton et 

al., 1999). 

3.1.3.1 1849/51 to 1949 

 Shoreline response along the ocean beaches between the USACE FRF Pier and Oregon 

Inlet for the period 1849/51 to 1915/16 illustrates a large area of shoreline advance north of 

Nags Head (up to about 3 m/yr; average change about 1.1 m/yr) and shoreline recession south 

of this point to Oregon Inlet (average change about -1.2 m/yr; Figure 3-5). Concurrently, the 

sand spit along the northern margin of Oregon Inlet advanced to the southeast at a rate of about 

36 m/yr. The inlet responded by migrating to the southeast, forcing northern Pea Island to 

erode to the southeast at about 31 m/yr. South of Oregon Inlet (northern 2.8 km of Pea Island), 

average shoreline recession was about 5.2 m/yr, approximately 1.6 times the average recession 

rate for an equivalent distance north of the inlet (-3.3 m/yr). Between 1915/16 and 1949, 

shoreline recession continued to be the dominant trend between Nags Head and Oregon Inlet 

(average recession of 1.7 m/yr; Figure 3-6). 
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Table 3-1. Summary of shoreline source data characteristics for the North Carolina coast 

between Kitty Hawk and Oregon Inlet. 

Date Data Source Comments and Map Numbers

1849/51 USC&GS Topographic Maps 

1:20,000 (T-292, T-351, T-354) 

First regional shoreline survey throughout study area using 

standard planetable surveying techniques. 

1915/16 USC&GS Topographic Maps 

1:40,000 (T-3538) 

Second regional shoreline survey (1:40,000 

reconnaissance scale) along the seaward coast of the study 

area using standard planetable surveying techniques. 

May - Dec 

1949 

USC&GS Topographic Maps 

1:20,000 (T-9159, T-9160, T-9278) 

First regional shoreline survey completed using aerial 

photos; about 3 km north of Nags Head to Oregon Inlet. 

May 1962 USC&GS Topographic Maps 1:10,000 

(T-11665, T-11672, T-12140) 

Maps produced from interpreted aerial photography flown in 

May 1962. 

May 1975 USC&GS Topographic Maps 1:10,000 

(TP-00887, TP-00889) 

Maps produced from interpreted aerial photography flown in 

May 1975. 

March 1980 NOS-USACE Shoreline Change Maps 

1:24,000 (Base Maps 51-55) 

Maps produced from interpreted aerial photography flown in 

March 16, 1980 (see Everts et al., 1983). 

Table 3-2. Positional uncertainty estimates associated with North Carolina shoreline 

surveys. 

Traditional Engineering Field Surveys (1849/51, 1915/16)

Location of rodded points 

Location of plane table 

Interpretation of high-water shoreline position at rodded points 

Error due to sketching between rodded points 

± 1 m 

± 2 to 3 m 

± 3 to 4 m 

up to ± 5 m 

Map Scale Cartographic Errors (all maps for this study) 1:10,000 1:20,000 

Inaccurate location of control points on map relative to true 

 field location 

Placement of shoreline on map 

Line width for representing shoreline 

Digitizer error 

Operator error 

up to ± 3 m 

± 5 m 

± 3 m 

± 1 m 

± 1 m 

up to ± 6 m 

± 10 m 

± 6 m 

± 2 m 

± 2 m 

Aerial Surveys (1949, 1962, 1975, 1980) Map Scale

1:10,000 1:20,000 

Delineating high-water shoreline position ± 5 m ± 10 m 

Sources: Shalowitz, 1964; Ellis 1978; Anders and Byrnes, 1991; Crowell et al., 1991. 

Table 3-3. Maximum root-mean-square uncertainties for North Carolina shoreline change 

data. 

1915/16 1949 1962 1975 1980 

± 31.61 ± 22.6 ± 17.3 ± 17.3 ± 25.8 1849/51 

(± 0.5)2

 (± 0.2) (± 0.2) (± 0.1) (± 0.2) 

± 32.4 ± 29.0 ± 29.0 ± 34.1 1915/16 

(± 1.0) (± 0.6) (± 0.5) (± 0.5) 

± 18.7 ± 18.7 ± 26.7 1949 

(± 1.4) (± 0.7) (± 0.9) 

± 11.8 ± 22.4 1962 

(± 0.9) (± 1.2) 

± 22.4 1975 

(± 4.5) 

Magnitude of potential error associated with high-water shoreline position change (m); 2 Rate of potential error 

associated with high-water shoreline position change (m/yr).
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3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-12 -9 -6 -3 0 3 6 9

Shoreline Change (m/yr)

1849/51

1915/16

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

Kitty

Hawk

Pier

Nags Head

FRF Pier

Figure 3-5. Shoreline position and change between the FRF Pier and Oregon Inlet, NC, 1849/51 to 

1915/16. 3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-15 -10 -5 0 5 10 15 20 25

Shoreline Change (m/yr)

1915/16

1949

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

FRF Pier

Kitty

Hawk

Pier

Nags Head

Figure 3-6. Shoreline position and change between the Nags Head and Oregon Inlet, NC, 1915/16 to 

1949. 
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However, greatest changes occurred adjacent to Oregon Inlet as it continued to migrate to the 

southeast at approximately 20 m/yr. The southern 1.3 km of Bodie Island advanced at an 

average rate of 8.4 m/yr, but the shoreline 3.8 km north of this point receded at a rate of 

4.7 m/yr, illustrating the influence of inlet dynamics on beach response. For the 100-yr record 

between 1849/51 and 1949, shoreline recession was the only trend, with increasing magnitude 

toward the inlet. The average recession rate between Nags Head and Oregon Inlet was about 

1.0 m/yr with maximum retreat rates of about 4 m/yr along southern Bodie Island (Figure 3-7). 

Northern Pea Island receded approximately 3.5 m/yr for the same period. 

3.1.3.2 1949 to 1980 

 Although four shorelines exist for this period of record, only the 1949 to 1980 change data 

are continuous from Nags Head to Oregon Inlet. All shorelines were captured from near-vertical 

aerial photography by the NOS. From 1949 to 1962, the southern 8 to 9 km of Bodie Island 

were compared. The northern 2 km of beach was slightly accretional, and the southern 6 to 

7 km north of Oregon Inlet was receding at an average rate of 7.2 m/yr (peak recession rate 

about 28 m/yr, Figure 3-8). These accelerated rates of change relative to any other time period 

reflect the impact of the March 1962 Ash Wednesday Storm (Dolan, 1987). Not only were 

shoreline recession rates magnified, but the net southerly growth of Bodie Island was 

temporarily reversed due to severe erosion of beaches adjacent to the inlet. By 1975, the 

southern 5.5 km of Bodie Island exhibited erosion and accretion trends consistent with longterm changes. The southernmost one km of beach adjacent to the inlet illustrated net advance 

at a rate of about 5.0 m/yr, and the 4.5-km long beach north of this point receded at an average 

rate of 5.2 m/yr (Figure 3-9). The beach along northern Pea Island receded at about 2.6 m/yr 

(maximum recession rate of approximately 16 m/yr). 

3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-12 -9 -6 -3 0 3 6 9

Shoreline Change (m/yr)

1849

1949

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

FRF Pier

Kitty

Hawk

Pier

Nags Head

Figure 3-7. Shoreline position and change between the Nags Head and Oregon Inlet, NC, 1849/51 to 

1949. 
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3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-30 -25 -20 -15 -10 -5 0 5 10

Shoreline Change (m/yr)

1949

1962

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

FRF Pier

Kitty

Hawk

Pier

Nags Head

Figure 3-8. Shoreline position and change along southern Bodie Island, NC, 1949 to 1962. 

3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-30 -25 -20 -15 -10 -5 0 5 10

Shoreline Change (m/yr)

1949

1975

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

Nags Head

Kitty

Hawk

Pier

FRF Pier

Figure 3-9. Shoreline position and change along southern Bodie Island, NC, 1949 to 1975. 
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 Net shoreline change between 1949 and 1980 documented recession everywhere except 

along the north beach adjacent to Oregon Inlet. From north of Nags Head to the accretion zone 

adjacent to Oregon Inlet, shoreline recession averaged 1.8 m/yr. However, the northern 15 km 

of beach receded at a rate of 0.9 m/yr, and the southern 7 km of the erosion zone receded at 

about 3.7 m/yr (Figure 3-10). The accretion area adjacent to the inlet extended approximately 

1.7 km, and the average rate of shoreline advance was 4.5 m/yr. South of the inlet for 3 km, 

shoreline recession dominated at an average rate of 4.1 m/yr (maximum change rate was 

-21 m/yr adjacent to the inlet). 

3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-30 -25 -20 -15 -10 -5 0 5 10

Shoreline Change (m/yr)

1949

1980

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

FRF Pier

Kitty

Hawk

Pier

Nags Head

Figure 3-10. Shoreline position and change between the Nags Head and Oregon Inlet, NC, 1949 to 1980. 

3.1.3.3 Cumulative Shoreline Position Change (1849/51 to 1980) 

 Shoreline position change between 1849/51 and 1980 documents persistent shoreline 

recession along most of the coast between the USACE FRF Pier and northern Pea Island 

(Figure 3-11). Average shoreline change north of Oregon Inlet was about -0.7 m/yr (σ = ±0.9 

m/yr). However, accelerated beach erosion on either side of Oregon Inlet resulted in net inlet 

migration to the south at about 3.5 km (27.1 m/yr). Shoreline recession along the southern 5.7 

km of Bodie Island was about 2.4 m/yr (σ = ±1.2 m/yr), whereas shoreline change north of this 

area to the FRF Pier averaged -0.5 m/yr (σ = ±0.4 m/yr). Along northern Pea Island, shoreline 

recession was approximately 3.8 m/yr (σ = ±0.7 m/yr) for the period of record (Figure 3-11). As 

with all time intervals, greatest shoreline changes were associated with beaches adjacent to 

Oregon Inlet. 
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3960000 3970000 3980000 3990000 4000000

UTM-y m( )

440000 450000

UTM-x (m)

-12 -9 -6 -3 0 3 6 9

Shoreline Change (m/yr)

1849

1980

advance

retreat

Oregon Inlet

Atlantic Ocean

North Carolina

Universal Transverse Mercator Zone 18, NAD 83

FRF Pier

Kitty

Hawk

Pier

Nags Head

Figure 3-11. Shoreline position and change between the FRF Pier and northern Pea Island, just south of 

Oregon Inlet, NC, 1849/51 to 1980. 

3.2 NEARSHORE BATHYMETRY CHANGE 

3.2.1 Bathymetry Data Base and Potential Errors 

Seafloor elevation measurements collected during historical hydrographic surveys are 

used to identify changes in nearshore bathymetry for quantifying sediment transport trends 

relative to natural processes and engineering activities. Two USC&GS bathymetry data sets 

were used to document seafloor changes between 1862/70 and 1970/75. In addition, 

nearshore bathymetry data collected by the USACE, Wilmington District, in 1996 between 

Oregon Inlet and Kitty Hawk supplemented the 1970/75 USC&GS data. Temporal comparisons 

were made for about 50 km of coast from 10 km north of Kitty Hawk to 3 km south of Oregon 

Inlet. Data extended offshore to about the 30-m depth contour (about 15 km offshore). The 

survey sets consist of digital data compiled by the National Geophysical Data Center (NGDC) 

and analog information (maps) that were compiled using standard digitizing procedures (see 

Byrnes and Hiland, 1994). 

 The first regional USC&GS bathymetric survey was conducted in 1862/70 (Table 3-4); 

data were registered in units of feet. The survey of Oregon Inlet in 1862 was conducted at a 

scale of 1:10,000, whereas offshore surveys (1868 and 1870) focused on regional data 

coverage at a scale of 1:40,000. The density of points was reasonable for characterizing 

coastal and shelf topography; however, the most recent survey (1970/75/96) recorded many 

more points for describing surface characteristics for the same area. The 1862/70 offshore 

surveys contained an adequate number of depths along each survey line, and longshore 

spacing of lines was about 0.5 to 1 km. As such, depth values are reasonable for describing 
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Table 3-4. Summary of bathymetric source data characteristics for the offshore area between 

Duck and Oregon Inlet, NC. 

Date Data Source Comments and Map Numbers 

1862/70 USC&GS Hydrographic Sheets 

1:10,000 (H-762) 

1:40,000 (H-965, H-1053) 

First regional bathymetric survey for offshore New Jersey; 

1862 - first survey of Oregon Inlet; 1868 - offshore area from 

Duck to south of Kitty Hawk (H-965); 1870 - offshore area 

from north of Nags Head to Pea Island (H-1053). 

1970/75 USC&GS Hydrographic Sheets 

1:5,000 (H-9527, H-9529, H-9530) 

1:10,000 (H-9525) 

1:40,000 (H-9137, H-9525, H-9171) 

Most recent offshore regional bathymetric survey; 1970 - 

offshore Kitty Hawk (H-9171), offshore Nags Head and 

Oregon Inlet (H-9155), Offshore Pea Island (H-9171); 1975 - 

Oregon Inlet surveys (H-9525, H-9527, H-9529, H-9530). 

1996 U.S. Army Corps of Engineers digital 

bathymetric survey 

Along the beaches and in the nearshore off Dare County, NC 

between Kitty Hawk and Oregon Inlet. 

bathymetric features and compared well with the 1970/75/96 survey set. The 1970/75 

bathymetric data are available in digital format from the NGDC, and the 1996 data area 

available from the USACE, Wilmington District. 

 As with shoreline data, measurements of seafloor elevation contain inherent uncertainties 

associated with data acquisition and compilation. Potential error sources for horizontal location 

of points are identical to those for shoreline surveys (see Table 3-2). These shifts in horizontal 

position translate to vertical adjustments of about ±0.3 to 0.5 m based on information presented 

in USC&GS and USACE hydrographic manuals (e.g., Adams, 1942). Corrections to soundings 

for tides and sea level change introduce additional errors in vertical position of ±0.1 to 0.3 m. 

Finally, the accuracy of the depth measurement adds uncertainty that is variable depending on 

the measurement method. Using this information, it is estimated that the combined root-meansquare error for bathymetric surface comparison between 1862/70 and 1970/75/96 is about 

±0.6 m. This estimate was used to denote areas of no significant change on surface 

comparison maps. 

 Because seafloor elevations are temporally and spatially inconsistent for the entire data 

set, adjustments to depth measurements were made to bring all data to a common point of 

reference. These corrections include changes in relative sea level with time and differences in 

reference vertical datums. Vertical adjustments were made to each data set based on the time 

of data collection. All depths were adjusted to NGVD and projected average sea level for 1980. 

The unit of measure for all surfaces is meters, and final values were rounded to one decimal 

place before cut and fill computations were made. 

3.2.2 Digital Surface Models 

 Historical bathymetry data within the study area provide geomorphic information on 

characteristic surface features that form in response to dominant coastal processes (waves and 

currents) and relative sea level change. Comparing two or more surfaces documents net 

sediment transport patterns relative to incident processes and sediment supply. The purpose of 

conducting this analysis throughout the study area is to document net sediment transport trends 

on the shelf surface and to quantify the magnitude of change to calibrate the significance of 

short-term wave and sediment transport numerical modeling results. Net sediment transport 

rates on the shelf were determined using historical data sets to address potential infilling rates 

for sand borrow sites. 
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3.2.2.1 1862/68/70 Bathymetric Surface 

 Bathymetry data for the period 1862/68/70 were combined with the 1849/51 shoreline 

data to create a continuous surface from the shoreline seaward to about the 25- to 30-m depth 

contour (NGVD). The most prominent geomorphic features throughout the study area are the 

linear offshore sand ridges north and south of Oregon Inlet (Figure 3-12). Because of data 

density limitations, these features are not as well defined as for the 1970/75/96 bathymetric 

surface. However, the presence of large N-S oriented ridges landward and seaward of the 

Federal-State OCS boundary is represented in the data set as a primary offshore sand source 

for beach nourishment. The characteristics of these shoal features are best defined north of 

Oregon Inlet for an area known as Platt Shoals. The origin of sand ridges has been associated 

with lateral inlet migration along a landward migrating shoreline (McBride and Moslow, 1991), 

suggesting that sediment associated with offshore sand ridges is compatible with modern beach 

deposits. Historical shoreline change data illustrate substantial lateral island migration and 

shoreline retreat between 1849/51 and 1980, providing a mechanism for oblique sand ridge 

formation on the shoreface. Geological data from the NCGS (Boss and Hoffman, 2001) 

illustrate that shoreface sand ridges are the most viable features for beach sand on the 

continental shelf in this area. Southward migration of southern Bodie Island indicates dominant 

southward-directed longshore transport within 5 to 10 km of the inlet (see Figure 3-11), and the 

predominance of shallow shoals on the north side of Oregon Inlet supports this conclusion. 

3.2.2.2 1970/75/96 Bathymetric Surface 

 General characteristics of the 1970/75/96 bathymetric surface are similar to those of the 

1862/68/70 surface with a couple of exceptions (Figure 3-13). First, the area of coverage 

extends much farther offshore the study area. Second, geomorphic features are better defined 

because the number of data points describing the surface is larger. The general shape and 

position of shoals is consistent for both surfaces. However, the detail associated with shoals 

along the coast and linear sand ridges on the shoreface provides an understanding of the 

relationship between potential sand borrow sites and coastal sedimentation processes. All 

potential sand borrow sites exist on offshore N-S oriented sand ridges, which have been linked 

with ancient inlet deposits during lower sea level (McBride and Moslow, 1991). 

 The shelf surface seaward of Oregon Inlet illustrates the influence of tidal inlet 

sedimentation processes on shelf morphology. The delta-shaped bulge in contours, marked by 

the 10-m depth contour, documents the longshore extent (about 5 km) of inlet-influenced 

sedimentation on shelf morphology. Although the tidal prism associated with this inlet is 

relatively large, ocean wave processes exert substantial influence on sediment transport 

patterns, creating ebb shoals in close proximity to the coast and an extensive flood shoal 

complex (Figure 3-14). Inlet shoals are composed primarily of sand contributed by longshore 

transport from adjacent beaches, so the genetic link between offshore sand ridges and the 

migration of inlets and beaches emphasizes the importance of shoal features as a viable source 

of sand for beach nourishment and coastal restoration. 
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Figure 3-12. Nearshore bathymetry (1862/68/70) for offshore Dare County, NC. 
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Figure 3-13. Nearshore bathymetry (1970/75/96) for offshore Dare County, NC. 
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Figure 3-14. Aerial photograph of Oregon Inlet illustrating the extent of ebb and flood shoal development. 

3.2.3 Shelf Sediment Transport Dynamics 

 Although the general characteristics of bathymetric surfaces appear similar for 1862/68/70 

and 1970/75/96, a digital comparison of these surfaces yields a difference plot that isolates 

areas of erosion and accretion for documenting sediment transport patterns and quantifying 

trends (Figure 3-15). The most significant changes occurring during this 100-yr interval were 

associated with deposition (and erosion) at and seaward of Oregon Inlet, along the beaches of 

Dare County, and associated with the movement of offshore sand shoals throughout the study 

area. Tidal exchange through Oregon Inlet mobilizes substantial quantities of sediment near the 

coastline and on the upper shoreface, resulting in spit growth along the downdrift margin of 

Bodie Island and shoal migration at and adjacent to the entrance, illustrated as areas of erosion 

(yellow to brown) and deposition (blue to green) on Figure 3-15. Without exception, beach and 

nearshore regions from Kitty Hawk to Pea Island are net erosional. On the shoreface, sediment 

transport patterns at sand ridges (e.g., Platt Shoals) illustrate net migration to the southsoutheast since 1868/70. The magnitude of erosion and deposition indicates an active shelf 

surface in response to storm and normal wave and current processes. A general pattern of 

alternating zones of accretion and erosion reflect the net southward migration of continental 

shelf sand ridges. 
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 Prominent zones of sediment deposition (green) seaward of the eroding beach and upper 

shoreface (orange and brown) are persistent throughout the study area. These zones of 

sediment accretion are associated with south-southeast directed shoal migration and 

development and migration of the ebb-tidal shoal at Oregon Inlet. Often, updrift zones of 

erosion are associated with downdrift linear deposits, illustrating the historical movement of 

shoals on the shelf surface. The greatest amount of bathymetric change on the shelf surface is 

associated with sand resource areas and the development of an ebb shoal seaward of Oregon 

Inlet. Sand volume change calculations for zones of accretion and erosion along the shore and 

on the shelf surface are used to estimate net sand transport rates (see Sections 3.2.4 and 

3.2.5). Historical transport rates are used to calibrate simulations of borrow site infilling and 

nearshore sand transport (Section 5.2). 

Figure 3-15. Nearshore bathymetry change (1862/68/70 to 1970/75/96) for offshore Dare County, NC. 
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3.2.4 Magnitude and Direction of Change 

 Patterns of seafloor erosion and accretion on the continental shelf from Kitty Hawk to Pea 

Island, NC documented the net direction of sediment transport throughout the study area 

(Figure 3-15). For the period 1862/68/70 to 1970/75/96, net sediment movement on the 

continental shelf is to the south. This direction of transport is consistent with historical shoreline 

change trends near Oregon Inlet. Although overall trends are helpful for assessing potential 

impacts of sand extraction from the OCS, the specific purpose of historical bathymetry change 

assessment is to quantify sediment erosion and accretion and to derive net transport rates 

specifically related to potential sand extraction sites. For the four potential sand resource areas, 

five borrow sites were identified for evaluating sand extraction scenarios based on discussions 

of beach replenishment needs with USACE, Wilmington District, and MMS personnel. 

 For Sand Resource Area 1, variations in sediment deposition over and adjacent to the 

proposed borrow site were evaluated for two locations, each equal to the area of the proposed 

borrow site. Potential transport rates available for infilling a proposed sand borrow site of this 

size would range from about 53,000 to 68,000 m3

/yr (6.9 to 8.9 MCM over about 100 years; 

Figure 3-16). This calculation assumes that sediment deposited in areas adjacent to potential 

borrow sites reflects the rate at which material would be available for infilling the borrow sites. 

For Areas 2 through 4, similar calculation procedures were applied to develop a range of 

potential infilling rates for each borrow site. Potential infilling rates at the borrow site in Area 2 

range from 39,000 to 70,000 m3

/yr, whereas to the south and east of this site in Area 3, 

potential infilling rates ranged from 20,000 to 27,000 m3

/yr. At Area 4, potential infilling rates 

ranged from 36,000 to 45,000 m3/yr. Overall, potential infilling rates derived from 100-yr 

historical deposition trends on the shelf surface adjacent to each of the sand borrow sites are 

relatively consistent. However, dredging geometry for each potential borrow site (depth to width 

to length), as well as the type of sediment available for infilling, are controlling factors for 

determining sediment infilling (see Section 5.2). 

 Table 3-5 summarizes potential extraction and infilling characteristics for each of the 

borrow sites. Although Area 4 is farthest offshore, the average time it would take to fill this site 

(based on 100-yr sedimentation trends) after mining all available sand would be about 57 years. 

Conversely, areas with the greatest amount of sand for beach nourishment (1 and 2) would take 

longest to fill if the entire volume were extracted. For a single fill of 2 MCM, the borrow sites in 

Areas 1 and 2 would refill in about 30 to 35 years. Infilling times would be about two times 

greater for the other borrow sites. 

Table 3-5. Sand volume extraction from potential borrow sites relative to computed infilling 

rates. 

Infilling Rate (m3 Sand /yr)

Borrow Site 

Borrow Site 

Sand 

Volume 

(MCM) 

Excavation 

Depth (m) 

D50 (mm) 

Low High 

Average 

Infilling 

Time 

(years) 

1 7.2 3 0.41 53,000 68,000 119 

2 5.8 3 0.50 39,000 70,000 106 

3 east 1.4 2 0.21 20,000 23,000 65 

3 west 2.5 3 0.27 24,000 27,000 98 

4 2.3 2 0.36 36,000 45,000 57 

 
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Figure 3-16. Polygon geometry and locations used for estimating infilling rates (blue) relative to sand 

borrow site locations offshore North Carolina. 
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3.2.5 Net Longshore Sand Transport Rates 

 A continuous zone of erosion along the shoreline is documented in Figure 3-16 as 

characteristic of littoral sand transport along the beaches in Dare County, NC. The littoral zone 

extends seaward to about the 10-m (NGVD) depth contour, which represents the approximate 

depth of closure (determined from geomorphic characteristics of the change surface [Figure 

3-15], profiles change analyses by Larson and Kraus [1994], and based on calculations of dl

from Hallermeier [1981] using USACE Wave Information Study [WIS] data statistics). Net 

longshore sand transport rates were determined between Kitty Hawk and Oregon Inlet by 

quantifying variations in beach erosion, as determined from historical bathymetry comparisons, 

in a sediment budget context. In Section 4.2.2.1, the distribution of longshore sediment 

transport potential was computed throughout the study area. A transport reversal was identified 

about 10 km north of Oregon Inlet. With this information (Q = 0 about 10 km north of the inlet) 

and erosion quantities for 3 km shoreline segments along the coast, a sediment budget was 

developed to document variations in net transport rates. North of the nodal point, beach and 

nearshore erosion varied from 50,000 to 110,000 m3

/yr. South of the nodal point, erosion rates 

varied from 75,000 to 170,000 m3/yr. Assuming about 25,000 m3/yr is transported offshore, net 

transport rates are about 160,000 m3

/yr near Nags Head and about 335,000 m3/yr near Kitty 

Hawk. These numbers are very consistent with those computed in Figure 4-17. In the same 

manner, south-directed transport adjacent to Oregon Inlet is about 354,000 m3

/yr. 

3.3 SUMMARY 

 Shoreline position and nearshore bathymetry change document four important trends 

relative to study objectives. First, the predominant direction of sediment transport on the 

continental shelf and along southern Bodie Island is north to south. However, littoral transport 

between Kitty Hawk and a point about 10 km north of Oregon Inlet is to the north. The greatest 

amount of shoreline change was associated with beaches adjacent to Oregon Inlet (-2 to -6 m/yr 

along southern Bodie Island); since 1849/51, southern Bodie Island has grown to the south at a 

rate of about 27 m/yr. Second, the most dynamic features within the study area are the 

beaches and shoals associated with Oregon Inlet. Areas of significant erosion and accretion 

are documented for the period 1862/68/70 to 1970/75/96, reflecting wave and current dynamics 

near the entrance and the contribution of littoral sand transport from the north to channel, shoal, 

and spit migration. 

 Third, alternating bands of erosion and accretion on the continental shelf east of FederalState boundary illustrate relatively slow but steady reworking of the upper shelf surface as sand 

ridges migrate from north to south. The process by which this is occurring at all resource areas 

suggests that borrow sites in these regions would fill with sand transported from the adjacent 

seafloor at rates ranging from 20,000 to 70,000 m3

/yr. For a 2 MCM sand extraction scenario, 

infilling times for borrow sites in Areas 1 and 2 would be about 30 to 35 years. 

 Finally, net longshore transport rates determined from seafloor changes in the littoral zone 

between Kitty Hawk and Oregon Inlet and nodal point information derived in Section 4.2.2.1 

indicate increasing transport rates north and south of a point about 10 km north of the inlet. Net 

longshore transport near Nags Head was about 160,000 m3

/yr to the north, increasing to about 

335,000 m3

/yr near Kitty Hawk. These rates are very consistent with those determined from 

wave and sediment transport modeling. Just north of Oregon Inlet, net transport rates were 

determined to be about 354,000 m3

/yr. 
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4.0 WAVE TRANSFORMATION NUMERICAL MODELING AND 

NEARSHORE SEDIMENT TRANSPORT 

 Excavation of a borrow site in the nearshore can affect wave heights and the direction of 

wave propagation. An offshore “hole” or “trench” can cause waves to refract toward the 

shallower edges of the borrow site. This alteration to the wave field by a borrow area may 

change local sediment transport rates, where some areas may experience a reduction in 

longshore transport, while other areas may show an increase. To determine potential physical 

impacts associated with dredging of a borrow site located offshore North Carolina in the vicinity 

of Bodie Island, wave transformation modeling and sediment transport potential calculations 

were performed for existing and post-dredging bathymetric conditions. Comparison of 

computations for existing and post-dredging conditions illustrated the relative impact of borrow 

site excavation on wave-induced coastal processes. 

 The most effective means of quantifying physical environmental effects of sand dredging 

from shoals on the continental shelf is through use of wave transformation numerical modeling 

tools that recognize the random nature of incident waves as they propagate onshore. Spectral 

wave models, such as STWAVE (STeady-state spectral WAVE model), REF/DIF-S 

(REFraction/DIFfraction model for Spectral wave conditions), SWAN (Simulation of WAves 

Nearshore), and others, typically provide more realistic results than monochromatic wave 

models relative to field measurements. As such, spectral wave transformation modeling was 

applied in this study to evaluate potential impacts to coastal and nearshore sites from long-term 

dredging and significant removal of sand from offshore sand borrow sites. Although 

interpretation of wave modeling results is relatively straightforward, evaluating the significance 

of predicted changes for accepting or rejecting a borrow site is more complicated. 

 As part of any offshore sand mining effort, the MMS requires evaluation of potential 

environmental impacts associated with alterations to nearshore wave patterns. To determine 

potential impacts associated with borrow site excavation, the influence of borrow site geometry 

on local wave refraction patterns is evaluated. Because large natural spatial and temporal 

variability exists within the wave climate at a particular site, determination of physical impacts 

associated with sand mining must consider the influence of process variability. A method based 

on historical wave climate variability, as well as local wave climate changes directly attributable 

to borrow site excavation, has been applied to determine appropriate criteria for assessing 

impact significance. 

 To directly assess impacts to coastal processes associated with sand mining, an 

approach has been utilized that considers spatial (longshore) and temporal aspects of the local 

wave climate, as described in Kelley et al. (2001). For this study, this method was applied by 

performing wave model runs using mean conditions developed using the entire 20-year WIS 

record to develop average conditions, and then 20 year-long blocks of the WIS record to 

determine annual variability of the wave climate along this shoreline. In this manner, temporal 

variations in wave climate are considered relative to average annual conditions. From these 

wave model runs, sediment transport potential curves are derived for average annual conditions 

(based on the full 20-year WIS record) and each one-year period (based on the 20 one-year 

wave records parsed from the full record). Applying this information, the average and standard 

deviation in calculated longshore sediment transport potential is determined every 200 m along 

the shoreline. 

 Assuming the temporal component of sediment transport potential is normally distributed, 

the suggested criterion for accepting or rejecting a potential borrow site is based on a range of 

one standard deviation about the mean. As proposed, the criteria would require that if any 
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portion of the sediment transport potential curve associated with a sand mining project exceeds 

one-half of a standard deviation of the natural temporal variability (which incorporates 1/3 of the 

variability) in sediment transport potential, the site would be rejected, or accepted conditionally. 

Conversely, a borrow site design would be accepted unconditionally as long as the transport 

potential change determined for post-dredging conditions at a site falls within the range of onehalf of a standard deviation. 

 Conditional acceptance of a borrow site design could be allowed for sites that change 

transport potential between one-half and one standard deviation at any point along a shoreline. 

This conditional acceptance would require either mitigation along the affected shoreline, which 

would likely be in the form of an appropriately sized beach nourishment, or a redesign of the 

proposed borrow site configuration to reduce impacts to within acceptable limits. If borrow site 

dredging impacts transport potential in excess of one standard deviation, the impact is 

considered too great for mitigation, and therefore the site must be either rejected or redesigned 

to reduce impacts to within acceptable limits. This methodology provides a useful indication of 

sediment transport variability relative to the natural system. 

 An example of this method taken from previous work (Kelley et al., 2001) is shown in 

Figure 4-1, where alterations in wave climate caused by dredging of Sandbridge Shoal, Virginia 

were determined to be not significant relative to natural variability. The maximum variation in 

sediment transport potential caused by dredging Sandbridge Shoal was determined to be 

approximately 25,000 m3

 per year, where the standard deviation of the natural sediment 

transport variability was approximately 100,000 m3

/yr. Due to the relatively high natural 

variability in wave climate in this area, an observer on the shoreline is unlikely to notice 

alterations in shoreline position caused by borrow site dredging. For this reason, sites with large 

natural variation in wave climate and associated sediment transport potential would be allowed 

to have larger impacts associated with an offshore sand mining project. 

 As a management tool for the MMS, this methodology provides several advantages over 

methods previously used to assess the significance of borrow site impacts. The primary 

advantages include: 

1. Observed long-term shoreline change is compared with computed longshore change 

in sediment transport potential. Close comparison between these two curves indicates 

that longshore sediment transport potential calculations are appropriate for assessing 

long-term natural change. Therefore, this methodology has a model-independent 

component (observed shoreline change) used to ground truth the model results. 

2. The method is directly related to sediment transport potential and associated shoreline 

change. Therefore, impacts associated with borrow site excavation can be directly 

related to their potential influence on observed coastal processes (annualized 

variability in shoreline position). 

3. Site-specific temporal variability in wave climate and sediment transport potential is 

calculated as part of the methodology. For sites that show little natural variability in 

inter-annual wave climate, allowable coastal processes impacts associated with 

borrow site dredging similarly would be limited, and vice versa. In this manner, the 

inter-annual temporal component of the natural wave climate is a major component in 

the determination of impact significance. 
77

Figure 4-1. Example of results for spatial/temporal variability method for determining significance of borrow site dredging impacts (Kelley et al., 

2001). Plots of modeled net transport potential and post-dredging change in transport for borrow sites located offshore Sandbridge, Virginia. Middle plot shows dredging significance criterion envelope (

±

σ) determined for this shoreline. The left plot of the shoreline 

is given for reference. 

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4. Similar to methodologies incorporated in previous MMS studies, the longshore spatial 

distribution of borrow site impacts is considered. However, the allowable limit of 

longshore sediment transport variability is computed from the temporal component of 

the analysis. Therefore, the final results of this analysis provide a spatially-varying 

envelope of allowable impacts in addition to the modeled impacts directly associated 

with borrow site excavation. The methodology accounts for spatial and temporal 

variability in wave climate, as well as providing a defensible means of assessing 

significance of impacts relative to site-specific conditions. 

4.1 ANALYSIS APPROACH 

Sediment transport rates along a coastline are dependent on wave climate in that area. 

For this study, nearshore wave heights and directions along the shoreline landward of the 

proposed borrow sites were estimated using the USACE spectral wave model STWAVE, which 

is used to simulate propagation of offshore waves to the shoreline. Offshore wave data, 

available from the WIS were used to derive input wave conditions for STWAVE. 

4.1.1 Wave Modeling 

 Developed by the USACE Waterways Experiment Station (WES), STWAVE v2.0 is a 

steady state, spectral wave transformation model (Smith et al., 1999). Two-dimensional 

(frequency and direction vs. energy) spectra are used as input to the model. STWAVE is able 

to simulate wave refraction and shoaling induced by changes in bathymetry and by wave 

interactions with currents. The model includes a wave breaking model based on water depth 

and wave steepness. Model output includes significant wave height Hs, peak period Tp, and 

mean wave direction θ . 

 STWAVE is an efficient program that requires minimal computing resources to run well. 

The model is implemented using a finite-difference scheme, on a regular Cartesian grid (grid 

increments in the x and y directions are equal). During a model run, the solution is computed 

starting from the offshore open boundary and is propagated onshore in a single pass of the 

model domain. This is why STWAVE can propagate waves only in directions within the ±87.5°

half plane. A benefit of using this single pass approach is that it uses minimal computer 

memory, because the only memory-resident spectral data are for two grid columns. As such, 

the changing wave spectra across each grid column are in turn computed using information 

solely from the previous grid column. 

 STWAVE is based on a form of the wave action balance equation. For this model, the 

wave action density spectrum, which includes the effects of currents, is conserved along wave 

rays. In the absence of currents, wave rays correspond to wave orthogonals, and the action 

density spectrum is equivalent to the wave energy density spectrum. A diagram showing the 

relationship of wave orthogonal, wave ray, and current directions is shown in Figure 4-2. The 

governing equation of wave transformation, using the action balance spectrum, in tensor 

notation is written as (Smith et al., 1999) 

( ) = ∑ −

∂

∂

r r

a ga

i

ga i

C C E S

x

C

ω ω

cos(μ α) (4.1) 

where 

E = E(f,θ) wave energy density spectrum, 

S = energy source and sink terms (e.g., whitecapping, breaking, wind input), 

α = wave orthogonal direction, 
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μ = wave ray direction (direction of energy propagation), 

ωr = relative angular frequency (2πfr), 

Ca, Cga = absolute wave celerity and group celerity, respectively. 

The breaking model in STWAVE is based on a form of the Miche criterion as discussed by 

Battjes and Janssen (1978). It sets a maximum limit on the zero-moment wave height (Hmo), the 

wave height based on the distribution of energy in the wave spectrum. The formulation of this 

model is 

Hmo(max) = 0.1L tanh (kd) (4.2) 

where L is the wavelength, k is the wave number (k = 2π/L), and d is the depth at the point 

where the breaking limit is being evaluated. This equation is used together with a simpler 

breaking model, which was used alone in earlier versions of STWAVE, where the maximum Hmo 

wave height is always expressed as a constant ratio of water depth 

Hmo(max) = 0.64 d (4.3) 

Figure 4-2. Diagram of wave and current vectors used in STWAVE. Subscript a denotes values in the 

absolute frame of reference, and subscript r denotes values in the relative frame of reference 

(with currents). 

An advantage of using Equation 4.2 over Equation 4.3 is that it accounts for increased wave 

breaking resulting from wave steepening caused by wave-current interactions. Once model 

wave heights exceed Hmo(max), STWAVE uses a simple method to reduce the energy spectrum, 

essentially to set the value of Hmo = Hmo(max). Energy at each frequency and direction is reduced 

by the same percentage. As a result, non-linear transfers of energy to high frequencies during 

breaking are not included in STWAVE. 

4.1.1.1 Input Spectra Development 

 Wave input conditions for simulations offshore North Carolina were developed using 

hindcast data from WIS Station AU2056 (Figure 4-3), which is located approximately 33 km 

northeast of Bodie Island, NC. This WIS record covers a 20-year period from January 1976 to 
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December 1995. Two wave roses showing percent occurrence of different wave conditions are 

shown in Figure 4-4. The first rose shows how wave height distribution varies with direction. 

Most waves (52%) in the WIS record fall within the compass sector between 60° and 120°. The 

dominant wave direction is east-northeast, from which 32% of waves in the record propagate. 

The mean height for all waves in the record is 1.5 m, with a standard deviation of 0.9 m. The 

mean height for waves along the dominant wave direction is 1.2 m, with a standard deviation of 

0.8 m. The second rose in Figure 4-4 shows the distribution of peak periods in the record. A 

significant number of wave events (32%) have peak periods greater than 9 sec, and the mean 

peak period for the entire record is 8.3 sec. 

Figure 4-3. Shoreline of southern Virginia and North Carolina with coarse grid limits and WIS wave input 

data station used to determine dredging impacts from offshore sand mining. 

 To reduce the offshore extent of the computational grid used by STWAVE, the program 

WAVETRAN was used to propagate WIS waves closer to shore, from a 37 m (MLLW) water 

depth at the WIS station, to a 24 m (MLLW) water depth approximately 17 km offshore (the 

seaward limit of the STWAVE grid). A wave rose of the transformed WIS record is shown in 

Figure 4-5. WAVETRAN is part of the Shoreline Modeling System (SMS) developed by WES 

(Jensen, 1983). Because bathymetric contours at these depths generally are oriented north to 

south offshore Oregon Inlet and Bodie Island, a shoreline orientation of 0° was used as an input 

to WAVETRAN. 
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Figure 4-4. Wave height and period roses for hindcast data from WIS Station AU2056 for the 20-year 

period between January 1976 and December 1995. Direction indicates from where waves 

were traveling, relative to true north. Radial length of gray tone segments indicate percent 

occurrence of each range of wave heights and periods. Combined length of segments in 

each sector indicate percent occurrence of all waves from that direction. 

Figure 4-5. WAVETRAN model output for WIS Station AU2056 data transformed to offshore boundary of 

STWAVE numerical grid. Directions are relative to STWAVE grid orientation, where 90°

corresponds to 66° true north, and 0° corresponds to 336° true north. 

 STWAVE input spectra were developed using a second numerical routine which 

re-creates a two-dimensional spectrum for each individual wave condition in the transformed 

WIS record. This program computes the frequency and directional spread of a wave energy 

spectrum based on significant wave parameters (i.e., wave height, peak period, and peak 

direction), as well as wind speed. This method is described by Goda (1985). The frequency 

spectrum S(f) is computed using the relationship 

[ ] 4

1/ 3

5

1/ 3 1/ 3

2

1/ 3 ( ) 0.257 ( ) exp 1.03( ) − − S f = H T T f − T f (4.4) 

known as the Bretschneider-Mitsuyasu spectrum, where H1/3 is the significant wave height, f is 

the discrete frequency where S(f) is evaluated, and T1/3 is the significant period, estimated from 

the peak wave frequency (fp) by 
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( ) p T 1/ 1.05f 1/ 3 = . (4.5) 

To compute the two-dimensional energy spectrum, a directional spreading function G(f,θ) must 

be applied to the frequency spectrum such that 

S(f,θ ) = S(f )G(f,θ ) . (4.6) 

In this method, the directional spreading function is computed using the relationship 





 



 = 2 ( , ) cos2 θ θ s Go G f (4.7) 

where s is a spreading parameter related to wind speed and frequency, θ is the azimuth angle 

relative to the principal direction of wave travel, and Go is a constant dependent upon θ and s. 

The spreading parameter s is evaluated using the expression 









⋅ ≥

⋅ ≤ = −

p p

p p

s f f f f

s f f f f

s

( / ) :

( / ) :

2.5

max

5

max (4.8) 

where 2.5

max 11.5(2 / )

− s = πfpU g . Wind speed U is therefore used to control the directional 

spread of the spectrum by increasing the directional spread with increasing wind speed. Finally, 

the constant Go is computed by evaluating the integral 

1

max 2

min 2

cos

−





















 



 = ∫

θ

θ

θ θ G d s

o . (4.9) 

The result is a wave energy spectrum based on parameters from the WIS record, and which 

distributes spectral energy based on wave peak frequency and wind speed. An example of a 

two-dimensional spectrum generated by this method is presented in Figure 4-6. 

 After re-creating a two-dimensional spectrum from the parameters given in the WIS 

record, each individual spectrum is sorted, or “binned”, by peak direction as well as by peak 

period. Wave spectra computed from wave parameters that fall within the limits of the individual 

direction and period bins are added together, and a mean spectrum for all waves in each bin is 

computed based on the total number of wave events in the bin. In total, seven direction bins 

and two period bins were used to characterize the wave data. From the 12 total bins, conditions 

used in the model runs of STWAVE were selected based on the percent occurrence and 

percent energy for conditions in each bin. 

 Selected conditions have a percent occurrence greater than one percent, and also contain 

more than one percent of the energy of the entire wave record. The nine conditions selected for 

model runs are shown in Table 4-1, with the significant parameters of each input spectrum. 
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Figure 4-6. Example of STWAVE input spectrum developed using WIS 20-year hindcast data together 

with the Goda method of computing frequency and direction spectrum. Plots show a) 

frequency distribution of energy at peak direction, b) directional distribution of energy at peak 

frequency, and c) surface plot of two-dimensional energy spectrum. Example is model Case 

5 (Hmo = 0.9 m, θmean = 130° grid relative). 

Table 4-1. Significant parameters of input wave spectra used for existing and postdredging STWAVE model runs. Storm input conditions are for a simulated 

10-year event. 

STWAVE 

Model Input 

Condition 

Percent 

Occurrence 

Hmo 

Wave Height 

Mean Wave 

Period, Tp

Peak Wave 

Direction, 

θp 

Peak Wave 

Direction, 

θp 

Direction Bin

 (m) (sec) (deg. true 

north) (grid relative) (grid relative)

1 9.4 1.1 5.1 1 25 0-30 

2 8.1 1.9 6.0 21 45 30-60 

3 8.7 1.5 6.7 56 80 60-90 

4 10.1 1.2 7.4 86 110 90-120 

5 16.3 0.9 7.6 106 130 120-150 

Period 

Band 1 

6 8.1 0.6 4.6 131 155 150-180 

7 6.0 1.9 11.5 66 90 60-90 

8 19.2 1.5 12.8 71 95 90-120 

Period 

Band 2 

9 6.3 1.3 11.3 101 125 120-150 

4.1.1.2 Grid Development 

 Together with the input spectra, three bathymetry grids were developed for the existing 

and post-dredging scenarios. Three coarse grids were developed to have the same 

geographical coverage, and differ by only modifications to bathymetry in the borrow area. One 

grid serves to provide existing wave conditions. The other two grids included dredged depths at 

Sites 1, 2, and 4, and alternately, Site 3 east or 3 west. The NOS was the primary source of 

bathymetric data used to create the grids (NOS, 1998). However, these data were 

supplemented by more recent bathymetric data. A contour plot of the post-dredging grid is 

shown in Figure 4-7. Depths at the offshore open boundary vary between 31 and 19 m, with a 

mean depth of approximately 25 m. 

a) b) c) 
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Figure 4-7. Color contour plot of coarse model grid (200 m x 200 m grid spacing) used with STWAVE. 

Depths are relative to NVGD 29. Borrow site locations are indicated by solid black lines, and 

fine grid limits are indicated by a dashed line. 

 Each coarse grid covers an area that extends approximately 17 km offshore and 85 km 

alongshore. The geographical limits of the grids were chosen based on the wave conditions 

selected for model runs. Wave conditions with relatively small angles to the shoreline require a 

wide grid so that the site of interest (i.e., the borrow site and affected shoreline) does not fall 

within the “shadow” of the lateral grid boundaries. The grids are made up of 87 cells in the 
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offshore direction by 425 cells in the alongshore direction, for a total of 36,975 grid cells, each 

with a spacing of 200 m. The grid axes are rotated counterclockwise by 24° to match the 

orientation of the shoreline in this area. 

 In addition to the four coarse grids, a single fine grid was developed to obtain greater 

resolution of waves in the nearshore area behind the borrow site (Figure 4-8). The same fine 

grid was used for both existing and post-dredging conditions. This fine grid extends 

approximately 3 km offshore and 18 km alongshore. This grid is made up of 300 cells in the 

offshore direction and 1,250 cells in the alongshore direction, for a total of 375,000 grid cells. 

The alongshore and cross-shore dimension of each cell is 20 m. Boundary conditions (wave 

spectra) for the fine grid were extracted from runs of the coarse grids. 

Figure 4-8. Color contour plot of fine model grid (20 m x 20 m grid spacing) used with STWAVE. Depths 

are relative to NGVD 29. Borrow site location is indicated by solid black line, and fine grid 

limits are indicated by dashed line. 
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4.1.2 Sediment Transport Potential 

 As a first step in evaluating sediment transport along the coastline of the North Carolina 

Outer Banks, calculations of sediment transport potential were performed to indicate the 

maximum quantity of transport possible based on a sediment-rich environment. Results from 

the spectral wave modeling formed the basis for changes in sediment transport rates along the 

beach because wave-induced transport is a function of various parameters (wave breaking 

height, wave period, and wave direction). Longshore transport depends on long-term 

fluctuations in incident wave energy and the resulting longshore current; therefore, annual 

transport rates were calculated from long-term wave statistics. 

 The sediment transport equation used for the longshore analyses is based on the work of 

the USACE (1984). In general, the longshore sediment transport rate is assumed to be 

proportional to the longshore wave energy flux at the breaker line, which is dependent on wave 

height and direction. Because the transport equation was calibrated in sediment-rich 

environments, it typically over-predicts sediment transport rates. However, it provides a useful 

technique for comparing erosion/accretion trends along the shoreline of interest. 

 Sediment transport computations were based on wave information at breaking for each 

grid cell along the modeled coastline. This shoreline segment incorporates the influence of all 

changes to the nearshore wave climate associated with proposed dredging activity. 

Computations of sediment transport rates for each of the nine wave conditions were performed 

and then weighted by the annual percentage occurrence. Sediment transport potential was 

computed for existing and post-dredging conditions. 

 The volumetric longshore sand-transport rate, Ql , past a point on a shoreline is computed 

using the relationship: 

s ga

I Q − ′ = ( 1)ρ

l

l (4.10) 

where Il

 is the immersed-weight longshore sand-transport rate, s is the specific gravity of the 

sediment, a’ is the void ratio of the sediment, g is the acceleration of gravity, and ρ is the density 

of seawater. 

 For this study, Il

 was computed using two methods. The first method is commonly 

referred to as the CERC formula, 

KPs I l = l (4.11) 

where K is a dimensionless coefficient and Pls is the longshore-directed wave energy flux 

computed using the following relationship: 

s Hsb b

g P α

γ

ρ sin 2

16

5 / 2

3 / 2

l = (4.12) 

where Hsb is the significant wave height at breaking, γ is the coefficient for the inception of wave 

breaking (γ=Hb/hb), and αb is the breaking wave angle. A value of K=0.4 was used for this 

study, appropriate for significant wave heights (computed by STWAVE), rather than the more 

familiar value K=0.77, which is used with RMS wave height. 
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 The second method used to compute the immersed-weight longshore sand-transport rate 

was described by Kamphuis (1990). This method is a modification to the original CERC formula 

that adds a dependency on median grain diameter of beach sand and the surf similarity 

parameter (Irabarren number), ξb, which is expressed as 

( )0.5

0 H / L

m

b

ξ b = (4.13) 

where m is the bottom slope, Hb is the wave-breaker height, and Lo is the incident deep-water 

wave length. The complete expression of Kamphuis is given by 

( ) () bT md Hs b

g I K g ξ θ

π

ρ sin 2

2

0.25 2.5 0.6

50

0.5

0.75

* −





 





l = (4.14) 

where the coefficient K* = 0.0013. 

4.2 MODEL RESULTS 

 Due to the redistribution in wave energy and alteration of wave directions resulting from 

offshore sand excavation, changes to the longshore sediment transport patterns will occur. 

Depending on the net direction of local sediment transport, the influence of borrow site 

conditions can either increase or decrease net littoral drift. 

4.2.1 Wave Modeling 

 From existing conditions model results, it can be seen that bottom features offshore the 

Outer Banks modify the wave field as it propagates shoreward. Model output presented in 

Figure 4-9 shows how waves respond to offshore shoals, even in relatively deep water (>15 m). 

For example, for the shoal feature in the vicinity of Resource Area 1, wave heights behind the 

shoal are about 0.4 m greater than wave heights at the northern and southern limits of the 

shoal. The shoal refracts the wave field, causing a slight focusing of wave energy behind the 

feature. Because energy is conserved, the focusing of wave energy behind the shoal causes a 

reduction of energy at the northern and southern edges of the shoal, which is apparent by the 

reduced wave heights in these areas. 

 In addition to the effects of bottom features far offshore, waves are refracted by the 

straight and parallel bottom contours in the nearshore. In Figure 4-9, fine grid model results 

show how wave directions change as the wave field propagates shoreward. For this southeast 

wave condition (as in Figure 4-10), waves refract and the mean direction of wave propagation 

becomes more shore-normal (perpendicular to the shoreline). In addition to the change in wave 

direction, wave heights also are modified by nearshore bathymetry. Waves begin to shoal 

(increase in height) about 500 m offshore, and increase in height by 0.2 m before breaking 

begins. Wave heights are reduced as energy dissipates in the surf zone, which is about 60 m 

wide in this example. 

 Output from post-dredging model runs indicate that wave heights within the borrow site 

are reduced relative to existing conditions, and this effect is more pronounced in cases that 

have greater wave heights. Wave fields landward of proposed borrow sites are modified by 

refraction. As waves propagate across a borrow site (deeper water than the surrounding area), 
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Figure 4-9. Example STWAVE output for coarse grid (200 m x 200 m cell) model of offshore North 

Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 sec). Color contours show Hmo wave height. 

Vectors indicate wave mean direction. Bottom bathymetry contours are shown as light black 

lines. Fine grid limits are indicated by dashed line. 
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Figure 4-10. Example STWAVE output for fine grid (20 m x 20 m cell) model of offshore North Carolina, 

model case 9 (Hmo = 1.3 m, Tp = 11.3 sec). Color contours show Hmo wave height. Vectors 

indicate wave mean direction. Bottom bathymetry contours are shown as light black lines. 

Fine grid limits are indicated by dashed line.
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wave refraction tends to bend waves away from the center of the excavation area and toward 

the shallower edges. The net effect is to create a “shadow” zone of reduced wave energy 

immediately landward of the borrow site and a zone of increased wave energy updrift and 

downdrift of the borrow site. 

 This shadowing effect is apparent in model results presented in Figure 4-11. In this figure, 

color contours represent wave height difference between model results computed for existing 

and post-dredging conditions. In the immediate vicinity of Site 2, for example, wave heights 

increased by a maximum of 0.05 m at the northern and southern edges of the borrow site and 

decreased by a maximum of 0.06 m behind the borrow site. In Figure 4-12, fine grid model 

results for the same wave condition illustrate that the magnitude of change in wave height has 

decreased closer to shore, as the color contours indicate a 0.01 m increase and 0.03 m 

decrease from existing conditions. 

 Because spectral wave model results are being used, and because different frequencies 

in the spectrum are refracted by varying degrees at the borrow site, the areas of increased and 

reduced wave height gradually diffuse as the wave field approaches the shore. A result of this 

energy diffusion is that the length of shoreline affected by a borrow site can be considerably 

longer than the borrow area. For this particular example, the length of affected shoreline is 

approximately three times longer than the alongshore dimension of the borrow site. 

 Another result of the gradual diffusion of wave energy caused by refraction of the wave 

spectrum is shown in Figure 4-11. In this figure, borrow sites farther offshore affect a longer 

length of shoreline, however, the actual magnitude of impact is reduced because the affected 

wave field has a greater distance over which to dissipate energy. This is evident in a 

comparison of the effect of Sites 1 and 2. Site 1 is larger than Site 2, but it is located farther 

offshore. Therefore, wave height change between existing to post-dredging conditions at the 

shoreline is smaller for Site 1 than changes resulting from the same waves propagating over 

Site 2. 

 Figure 4-11 demonstrates how borrow site geometry influences potential shoreline 

impacts. In this example, wave field modifications from Sites 2 and 3 west illustrate that Site 2 

has a greater impact on nearshore wave heights. Though both sites are excavated to the same 

depth (3 m), Site 3 west has a smaller surface area than Site 2. Site 3 west also is located in 

deeper water, as the mean depth at the site is approximately 2 m deeper than Site 2. The 

increased impact resulting from sand excavation at Site 2 occurs due to the combination of 

these two characteristics (size and depth). 

 Additional examples of wave model output for offshore North Carolina are illustrated in 

Figures 4-13 (Case 2) and 4-14 (Case 8). For Case 2, shoals offshore Oregon Inlet produce a 

small increase in wave height landward of the shoals, with a corresponding small decrease in 

wave height seaward of the shoals. Otherwise, no significant shoaling or refraction is observed 

in this relatively short period wave case. 

 Model output for wave Case 8 (see Table 4-1) is shown in Figure 4-14. This wave 

condition has a significantly longer period than Case 2, and as a result, waves are more 

affected by offshore bathymetry gradients. Although the direction of wave propagation is not 

modified as much as was indicated in previous examples, wave heights have changed 

significantly (e.g., a maximum height of 2.4 m at the southern side of Oregon Inlet) relative to 

offshore conditions. At the offshore shoals directly east of the inlet, wave heights increase 

approximately 0.7 m over the offshore boundary condition. Several shoal areas along the 

modeled coastline show similar impacts on wave heights, including the area encompassing the 

two modeled borrow sites. 
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Figure 4-11. Wave height difference plot between existing and post-dredging conditions 

(Hdifference = Hpost – Hpre) for coarse grid (200 m x 200 m cell) model of offshore North 

Carolina, model case 9 (Hmo = 1.3 m, Tp = 11.3 sec) , for run which included excavation at 

Sites 1, 2, 3 west, and 4. Bottom bathymetry contours are shown as light black lines. 
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Figure 4-12. Wave height difference plot between existing and post-dredging conditions 

(Hdifference = Hpost – Hpre) for fine grid (20 m x 20 m cell) model of offshore North Carolina, 

model case 9 (Hmo = 1.3 m, Tp = 11.3 sec), for run which included excavation at Sites 1, 2, 3 

west, and 4. Bottom bathymetry contours are shown as light black lines. Fine grid limits are 

indicated by dashed line. 

 

 Influence of Borrow Site 3 west 

Influence of Borrow Site 2 

Influence of Borrow Site 1 
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Figure 4-13. Plot of STWAVE model output for offshore North Carolina wave Case 2 (Hs = 1.9 m, 

Tpeak = 6.0 sec, θpeak = 21 deg). Color contours indicate wave height, and vectors show mean 

direction of wave propagation. 
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Figure 4-14. Plot of STWAVE model output for offshore North Carolina wave Case 8 (Hs = 1.5 m, 

Tpeak = 12.8 sec, θpeak = 71 deg). Color contours indicate wave height, and vectors show 

mean direction of wave propagation. 
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 Plots of wave height change from existing and post-dredging conditions at Sites 1, 2, 3 

west, and 4 are shown in Figures 4-15 and 4-16 for wave Cases 2 and 8. For Case 2 results 

(Figure 4-15), the area of influence for the combination of the four modeled sites extends 

approximately 40 km along the coastline. The long extent of influence is the result of the 

approach angle for offshore waves. The greatest increase in wave heights resulting from 

potential dredging was south of Site 2, where wave heights increased 0.09 m over existing 

conditions. The area of greatest wave height reduction is located near Site 1, where wave 

heights decreased 0.09 m from existing conditions. 

 Figure 4-16 presents the wave height difference plot for Case 8 (see Table 4-1). Sites 2 

and 4 have an observable overlapping region of influence, as Site 4 is located offshore Site 2, 

along the direction of wave propagation. The area of maximum increased wave heights for 

post-dredging conditions is located at the northern-most corner of Site 1, where wave heights 

increase 0.09 m over existing conditions. The area of maximum wave height decrease is 

located near Site 1, where wave heights are reduced by 0.12 m from existing conditions. This 

area of maximum reduced wave heights occurs at the landward corner of Site 1. For Case 8, 

the length of affected shoreline, to where borrow site “shadows” propagate, extends 

approximately 40 km, starting from about 3 km north of Oregon Inlet. 

4.2.2 Sediment Transport Potential 

 Comparisons of average annual sediment transport potential were performed for existing 

and post-dredging conditions to indicate the relative impact of dredging to longshore sediment 

transport processes. Sediment transport potential is a useful indicator of shoreline impacts 

caused by offshore borrow sites because the computations include the borrow site influence on 

wave height and direction. For the study area, the net sediment transport potential associated 

with average annual conditions was computed. For comparison, transport potential was 

computed using both the coarse grid and fine grid model results. 

 Both net and gross sediment transport potential results are shown in Figure 4-17, for a 

35-km stretch of coastline from Oregon Inlet to approximately 9 km south of the USACE Duck 

FRF. Results were computed using existing wave conditions and post-dredging conditions for 

two alternate borrow site configurations, 1) Sites 1, 2, 3 east, and 4 modeled together, and 

2) Sites 1, 2, 3 west, and 4 modeled together. The plot of gross and net transport potential 

indicates that there is a reversal of the direction of transport south of 3,970,000 m UTM 

northing, at Bodie Island. North of this spot, net transport is to the north, while south of this 

point to Oregon Inlet, the net transport is strongly to the south. The computed north- and southdirected transport potential shows that transport is strongly bi-directional, with a gross transport 

magnitude of approximately 600,000 m3

/yr far north of Oregon Inlet, but with a net transport 

magnitude of only 250,000 m3

/yr. Closer to the inlet, the littoral drift becomes more unidirectional and to the south, with gross and net transport potential magnitudes peaking at over 

600,000 m3

/yr. 

 A plot of transport potential change for the two borrow site configurations also is 

presented in Figure 4-17. The maximum negative change (post-dredging minus existing 

condition) in computed net sediment transport potential occurs with the second configuration 

(Sites 1, 2, 3 west, and 4), where the peak change is -34,000 m3

/yr, or 45% of the net transport 

potential at this point. The maximum positive change is approximately 14,000 m3

/yr or only 8% 

of the net transport potential computed at this point. 
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Figure 4-15. Plot of wave height change between existing and post-dredging (∆ = Hpost-Hpre) conditions at 

Borrow Sites 3 east and 3 west for STWAVE model output for offshore North Carolina wave 

Case 2 (Hs = 1.9 m, Tpeak = 6.0 sec, θpeak = 21 deg). 
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Figure 4-16. Plot of wave height change between existing and post-dredging (∆ = Hpost-Hpre) conditions at 

Borrow Sites 3 east and 3 west for STWAVE model output for offshore North Carolina wave 

Case 8 (Hs = 1.5 m, Tpeak = 12.8 sec, θpeak = 71 deg). 

4.2.2.1 Littoral Drift Comparison with Existing Studies 

 Longshore transport potential computations are contrary to the classical assumption that 

net transport along the entire Outer Banks is southerly. A summary of past efforts to quantify 

transport volumes at the Outer Banks was given by Inman and Dolan (1989). Results for this 

study indicate that a nodal point (where net transport direction changes) exists far north of the 

present study area, at False Cape, VA, and that south of this point net transport is southerly with 

a magnitude of 660,000 m3

/yr (Figure 4-18). Other studies cited by Inman and Dolan (1989) 
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agree with this result. Net transport rates at Nags Head, NC (approximately 3,980,000 UTM 

northing) were estimated at 686,000 m3

/yr to the south by the USACE, Wilmington District 

(1980), and 817,000 m3/yr to the south by Birkemeier et al. (1981). 

 Of these three historical estimates of the net magnitude and direction of littoral drift in this 

region, results of Inman and Dolan (1989) are based on the most rigorous method. For that 

study, the original WIS Phase III data (Jensen, 1983) was refracted to breaking depth for 

stations along the North Carolina and Virginia coastlines (Stations 77 to 87). Estimates 

determined for the two other studies (USACE, Wilmington District, 1980; Birkemeier et al., 1981) 

depended on long-term wave height data collected at the Nags Head pier, and a record of 

visually observed wave directions. 

 This present study has benefited from updated WIS offshore wave records, and a longterm directional wave time series available from the USACE FRF. A comparison between the 

most recent WIS hindcast record (refracted to a depth of 10 m), the original WIS Phase III 

hindcast, and the long-term data record collected at the USACE FRF at Duck, NC is presented 

in Figures 4-19, 4-20, and 4-21. In Figure 4-19, a rose plot of the original WIS Phase III data 

(Station 83) at Duck, NC shows how wave heights are distributed by direction, oriented to the 

shoreline. Waves are widely spread in this hindcast, but there is an apparent bias to larger 

waves (more energy) propagating from the north, which would support the net southerly drift 

determined by Inman and Dolan (1989). In contrast, the recent (1990 to 1999) directional wave 

data collected at the Duck FRF and the updated WIS hindcast data show a different trend. 

Recent data sets illustrate that wave occurrences are focused more from directly offshore 

(compared with WIS Phase III data). In addition, more energy propagates from the south, which 

indicates greater northerly-directed transport potential (consistent with the results of this study). 

 An additional comparison between the three data sets is presented in Table 4-2 and 

Figure 4-22. Table 4-2 shows the distribution of wave energy (proportional to height squared) 

separated into six bins oriented to the shoreline azimuth. There is good correlation between the 

wave energy distribution of the recent WIS hindcast data and the Duck FRF directional wave 

data. The energy distribution of the old WIS Phase III data is significantly different from the 

other two sets in this comparison. This difference is also observed in the histogram plot in 

Figure 4-22. This plot shows that the old WIS Phase III data has more energy in bins that would 

tend to cause net southerly littoral drift, in contrast to the updated WIS and the Duck data, which 

show more energy in bins that would tend to cause net northerly littoral drift. All three of these 

data sets show a similar tendency for a strongly bi-directional gross transport, where the 

magnitude of gross transport (the sum of northerly and southerly drift) is significantly greater 

than the observed net transport. 

 Good agreement between recent WIS hindcast data and directional wave gage data from 

the FRF provides confidence in the computed net transport potential along the shoreline 

between Oregon Inlet and the FRF. 
99

Figure 4-17. Plot of computed transport potential for existing conditions, and transport potential difference between existing and post-dredging 

conditions for modeled cases where Sites 3 east and 3 west are included alternately. The middle plot shows computed net and gross south and north directed transport for wave conditions derived from 20-year WIS hindcast. The right-hand plot shows change in transport from existing to post-dredging conditions, for Sites 1, 2, and 4, modeled with 3 east and 3 west separately. 

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Figure 4-18. Wave energy flux (ECn) and sand transport potential along the Hatteras littoral cell, using 

wave climate data from the original WIS Phase III simulations (from Inman and Dolan, 1989). 

Figure 4-19. WIS Phase III hindcast data for Station 83, for the simulation period from January 1956 

through December 1975. Directions are relative to approximate shoreline orientation (340°) 

at Duck, NC (20° on these plots corresponds to 0° true north). 
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Figure 4-20. WAVETRAN output using WIS Station AU2056. Wave record is refracted into 10 m water 

depth corresponding to WIS Phase III depth. Directions are relative to approximate 

shoreline orientation (340°) at Duck, NC (20° on these plots corresponds to 0° true north). 

Figure 4-21. Duck FRF data for 8 m directional wave array (January 1990 to December 1999). Directions 

are relative to approximate shoreline orientation (340°) at Duck, NC (20° on these plots 

corresponds to 0° true north). 

Table 4-2. Comparison of wave energy distribution between updated WIS record 

(transformed into 10 m water depth), FRF 8 m array record, and original WIS 

Phase III record. Absolute difference values show percentage difference of 

FRF 8 m array and original WIS Phase III record compared to updated WIS 

record (Station AU2056). 

Updated WIS, 

(1976-1995) 

Duck Data 

(1990-1999) 

Phase III WIS Data 

Direction Bin (1956-1975) 

(Azimuth degrees, 

shoreline relative) Percent Energy 

of Record 

Percent Energy 

of Record 

Absolute 

Difference from 

Updated WIS 

Percent energy 

of Record 

Absolute 

Difference from 

Updated WIS 

0-29.9 0.9 0.2 -0.7 3 2.1 

30-59.9 5.7 7 1.3 27.1 21.4 

60-89.9 40.5 40.8 0.3 39.5 -1 

90-119.9 35.0 42.5 7.5 16.2 -18.8 

120-149.9 15.4 9.4 -6 11.9 -3.5 

150-180 2.5 0.1 -2.4 1.9 -0.6 
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Figure 4-22. Histogram of relative wave energy for wave records divided into six directional bins. Bar 

length is determined by the product of percent occurrence and squared mean wave height of 

each directional bin. Directions are relative to approximate shoreline orientation (340°) at 

Duck, NC (20° on this plot corresponds to 0° true north). 

4.2.2.2 Model Comparison with Historical Shoreline Change 

 To ensure that spectral wave modeling and associated longshore sediment transport 

potential could be used effectively to evaluate long-term alterations to the littoral system, a 

comparison of model predictions with observed shoreline change was performed. This analysis 

provides a semi-quantitative method for determining whether a) wave-induced longshore 

transport is responsible for observed shoreline change, and b) long-term shoreline change 

trends are consistent with shorter time-period (20-year) sediment transport potential analyses. 

For the four potential sand resource areas, an evaluation of model output was performed using 

a comparison of computed gradients in sediment transport to historical shoreline change data. 

The basis for this comparison is the relationship between shoreline movement and the 

longshore gradient of sediment transport. Simply expressed, this relationship is 

t

x

y

Q

∂

∂

∝

∂

∂ (4.15) 

where Q is sediment transport, y is alongshore distance, x is the cross-shore position of the 

shoreline, and t is time. A comparison of results should illustrate similar trends in long-term 

shoreline change and transport potential computed using wave conditions that represent longterm average conditions. Good general agreement between these two quantities would suggest 

that the transport potential model reasonably represents long-term coastal processes for a given 

area, and thus, the model’s ability to predict the likely impacts that would result from offshore 

dredging. 

 The time variation in shoreline position was determined from an analysis of historical 

shoreline data for each of the study areas. Regional change analysis provides a without-project 

assessment of shoreline response for comparison with predicted changes in wave-energy 

focusing at the shoreline resulting from potential offshore sand dredging activities. Because 
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continuous measurements of historical shoreline change are available at 50-m alongshore 

intervals, model results (wave and sediment transport) at discrete intervals along the coast can 

be compared with historical data to develop process/response relationships for evaluating 

potential impacts. In this study, shoreline data covering the periods 1849 to 1980 for Dare 

County, NC were used to quantify trends (see Section 3.1). Methods used for compiling and 

analyzing historical data sets are described in Byrnes and Hiland (1994). Alongshore variations 

in sediment transport were determined using the computed values of transport potential for each 

shoreline for modeled existing conditions. The comparison of shoreline change to the modeled 

transport gradient for North Carolina is shown in Figure 4-23. 

 Trends in shoreline change generally agree with modeled transport gradients for the North 

Carolina coast north of Oregon Inlet (Figure 4-23). Results of both analyses illustrate a stable to 

erosional shoreline, with an area of maximum erosion between 5 and 7 km north of Oregon 

Inlet. For the modeled transport gradient, there is an area of accretion approximately 3 km 

north of the point of maximum erosion that is not indicated in the shoreline change analysis. 

This may be due to al lack of detailed nearshore bathymetry data for a 2-km section of coastline 

at this location. Bathymetry data used for developing the model grid was digitized from a NOAA 

navigational chart and does not have a high level of detail as is available in the data used for 

adjacent sections of coast. In addition, severe erosion observed immediately north of Oregon 

Inlet may have created an erosional hot-spot that has propagated to the north as shoreline 

orientation changed over the past century. 

 The gradient in sediment transport potential was not expected to simulate this process 

that likely occurs over a time period spanning several decades. Significant migration of Oregon 

Inlet also may be responsible for some of the differences between observed and modeled 

shoreline change trends, where the peak in erosion likely has migrated south with the inlet. 

Therefore, the peak erosion area determined from the gradient of modeled transport potential, 

based on 20 years of recent wave information, may be more representative of present 

conditions than the long-term shoreline change (based on more than 100 years of shoreline 

data). Overall, good agreement exists between observed shoreline change and longshore 

gradient in modeled transport potential. Minor differences between the two methods, especially 

in the region of maximum erosion, likely are due to long-term alterations (spanning several 

decades) in shoreline position and the historical migration of Oregon Inlet. 

4.2.2.3 Significance of Proposed Dredging 

 The significance of the changes to longshore transport along the modeled shoreline that 

result from dredging the proposed borrow sites to their maximum design depths was determined 

using the method outlined in Kelley et al., (2001). For the determination of dredging impact 

significance, 20 model runs in addition to the 27 existing and post-dredging runs were executed. 

For this study, 20 one-year periods were run, using the same directional binning as the existing 

and post-dredging runs. Each one–year period modeled represents a single year of the 20-year 

WIS hindcast record. Sediment transport potential was computed for each one-year period. 

The standard deviation of transport potential then was computed at each separate grid node, 

providing an estimate of the annual variability of the sediment transport climate along the 

shoreline. This method therefore incorporates the temporal and spatial variability of transport 

potential along the modeled shoreline. 
104

Figure 4-23. Comparison of historical shoreline change and gradient of modeled transport potential (dQ/dy) for the North Carolina shoreline. Color 

bars indicate whether the shoreline is accretional, stable, or erosional. 

highly erosional stable to erosional stable stable to accretional 

Oregon Inlet 

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 The criterion for determining dredging significance is one-half of a standard deviation 

(±0.5σ) in this case where the 20-year WIS record was run as 20 individual years. This criterion 

is more restrictive than the ±σ value used in Kelley et al. (2001) for this same coastline because 

the original significance criterion was computed using the 20-year WIS record split into five fouryear periods, which results in a smaller value of the standard deviation. For the North Carolina 

coastline, the standard deviation computed using five four-year periods is approximately 80% of 

the standard deviation computed for the same shoreline using 20 one-year periods. 

 In Figure 4-24, the computed change in transport potential for the two modeled scenarios 

(where Sites 3 east and 3 west were modeled alternately with Sites 1, 2, and 4) falls within the 

0.5σ significance envelope determined for this shoreline. Therefore, according to this analysis, 

the modeled borrow site configurations are acceptable without any additional stipulations. It is 

likely that if Sites 3 east and 3 west were dredged simultaneously with the other three sites, the 

resulting change in computed sediment transport potential would exceed the 0.5σ significance 

envelope. However, it is estimated that the modeled change would occur well within ±σ, the 

level where borrow site configuration design would be rejected or modified so that impacts are 

within acceptable limits. If simulated potential change is greater than ±σ, appropriate mitigation 

may be required along the adversely affected shoreline to mitigate the impact, such as a 

redesign of the borrow site configuration. From our analysis, the redesign would likely invlove a 

reduction in maximum allowable dredged depth at a given site. 

4.3 SUMMARY 

 The wave transformation numerical model STWAVE was used to simulate how wave 

fields are modified by the bathymetry offshore North Carolina. Wave conditions run in STWAVE 

were developed using a 20-year WIS wave hindcast for a station offshore Dare County, NC. 

The same wave conditions were run for existing and post-dredging conditions. Wave model 

output was then used to determine sediment transport potential along the entire shoreline, for 

both existing and post-dredging conditions. The alongshore variation of the computed gradient 

of transport potential was compared to measured shoreline change to ensure that spectral wave 

modeling and associated longshore sediment transport potential could be used effectively to 

evaluate long-term alterations to the littoral system 

 Once the change in sediment transport potential was determined between existing and 

post-dredging conditions, the significance of these changes was determined by applying a 

significance criterion based on the natural temporal and spatial variability of sediment transport 

along the modeled coastline. An additional 20 wave model runs were executed to determine the 

significance criterion envelope. Each of the 20 runs represented a single year of the 20-year 

WIS hindcast wave data set. The standard deviation, σ, of sediment transport potential was 

computed for the entire coastline. The final determination of dredging impact significance was 

made by comparing actual change in transport potential between existing and post-dredging 

conditions to a significance envelope of one-half the standard deviation (±0.5σ) along the 

shoreline (Figure 4-24). It was determined that no significant changes to longshore sediment 

transport will result from the modeled borrow site configurations, where Sites 3 east and 3 west 

were modeled separately. If sites were dredged simultaneously, the impacts are estimated to 

exceed the ±0.5σ, and therefore would require mitigation along the affected shoreline, or a 

redesign of the borrow site configuration, likely a reduction in maximum design depth at one of 

the sand borrow sites. 
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Figure 4-24. Plot of transport potential difference between existing and post-dredging conditions, 

including the maximum influence envelope. 
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5.0 CIRCULATION AND OFFSHORE SEDIMENT TRANSPORT 

DYNAMICS 

5.1 CURRENTS AND CIRCULATION 

 Circulation patterns observed at specific areas within the study region were evaluated 

within the context of potential offshore sand mining operations. The following discussion uses 

long-term current measurements obtained during previous studies in the region to provide an 

understanding of temporal variations of inner shelf circulation (time scales of hours to months). 

The analyses presented in this section describe circulation characteristics within the study 

region, including major forcing influences, time scales of variability, and the magnitude of 

resulting currents. Results from this section were used to provide estimates of sediment 

transport potential at proposed offshore borrow sites. 

5.1.1 Historical Data Analysis 

 Historical current records for data collected at the FRF in Duck, NC were chosen for 

detailed analysis of current processes. Current data were collected at two sites; a MarshMcBirney single point current meter (MMB) at the 8-m depth contour in 5 m of water and an 

upward looking RD Instruments Acoustic Doppler Current Profiler (ADCP) anchored to the 

seafloor at the 13-m depth contour. The MMB was positioned at 36°11.30’ N, 75°44.60’ W and 

recorded data intermittently from April through December 1997. ADCP measurements were 

obtained from January through December 1997 in approximately one month continuous records 

at 36°11.39’ N, 75°44.15’ W. 

 All current data were first rotated from a north/east coordinate system to a crossshelf/along-shelf coordinate system. This rotation of the coordinate system allowed analysis of 

currents flowing normal and parallel to the shoreline and nearshore bathymetric contours. The 

sign convention holds that positive across-shelf flow is directed offshore and negative acrossshelf flow is directed onshore. Positive along-shelf flow is directed approximately northnorthwest; negative flow is directed approximately south-southeast. 

5.1.1.1 Description of Observed Currents 

 Current measurements at FRF locations throughout the approximate one-year period 

revealed temporal and spatial variability, but mean flow was southerly, approximately along the 

inner shelf bathymetric contours. Strongest flow was observed in the along-shelf direction, with 

peak velocities of nearly 150 cm/sec at the surface and 100 cm/sec near the seabed; maximum 

currents were directed down-shelf, or to the south (Figure 5-1). Maximum up-shelf (northward) 

currents occasionally reached 80 cm/sec at the surface. Up-shelf bottom currents never 

exceeded 40 cm/sec (Figure 5-2). Flow reversals, when currents were directed toward the 

north then reversed to flow in a southerly direction, were noted frequently. 

 In the cross-shelf direction, mean flow was oriented onshore at the surface, consistent 

with upwelling processes that push bottom waters up onto the shelf. Maximum across-shelf 

flow was 70 cm/sec (directed onshore) at the surface and 30 cm/sec (directed offshore) at the 

bottom. The counter flow of surface water and near-bottom currents provides evidence of a 

circulation cell due to upwelling. A more detailed analysis of the current regime at the ADCP 

location (13 m) was possible following numerical separation of overall measured currents into 

known physical processes. The MMB data primarily were analyzed for comparison with ADCP 

current measurements revealed along the inner shelf. 
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Figure 5-1. Vertical profile of average and maximum current speeds from January through December 

1997. Maximum currents were directed southerly at 150 cm/sec (≈ 3 knots) in the upper 

water column and 100 cm/sec (≈ 2 knots) near bottom. 

Figure 5-2. Rose diagram of currents measured at the surface (1.25 m), mid-depth (6.75 m), and nearbottom (11.75 m). Rings represent 10%, 20% and 30% occurrence, and shading 

corresponds to current speed ranges as denoted by the scale. 

5.1.1.2 Numerical Decomposition of Historical Current Data 

 Currents observed along the continental shelf represent the cumulative effects of many 

different physical processes, each possessing unique time scales and amplitudes. These 

processes occur simultaneously; hence, the current observed at any one time can be 

considered the summation, or superposition, of all individual processes. This section describes 

the numerical procedures used to separate the observed currents into individual subsets, each 
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with specific time scales of variability. This procedure allows analysis of each process to 

determine their relative importance to total circulation in the region. 

 Separation of the total signal into specific process components was performed using 

various numerical analysis techniques, such as tidal harmonic decomposition, as well as the 

application of a series of low-, band-, and high-pass filters. Results of the numerical separation 

analysis represent subsets of individual time series. Each subset represents a specific physical 

process, such as: 

• High-frequency currents (non-tidal processes with periods less than approximately 

33 hours); 

• Tidal currents (diurnal and semi-diurnal constituents); 

• Wind-driven currents (1 to 33 day frequency band). 

 The first step in the separation analysis is to remove tidal currents from the raw data using 

harmonic analysis. Harmonic analysis calculates the amplitude and phase of 21 individual tidal 

constituents using a least-squares fit of the constituent sinusoid to the raw data signal. Tidal 

constituents removed included K1, M2, M4, M6, S2, N2, O1, S4, S6, M8, MK3, MN4, MS4, 2N2, 

OO1, M1, J1, Q1, 2Q1, L2, and 2SM2. Most constituents represent high-frequency tides, or 

tides having periods less than approximately 28 hours (diurnal tides). 

 This analysis produces a separation of total observed currents into two time series: one 

time series is predicted tides, based on a reconstruction of individual tidal components (the 

summation of 21 sinusoidal functions), and the second time series is non-tidal or residual 

currents. Residual currents were generated by subtracting (point by point) the reconstructed 

tidal time series from the original signal. 

 The residual signal became the basis for subsequent analyses. The first step in 

processing was to remove the remaining high-frequency energy. This was accomplished by 

applying a PL33 low-pass filter over the residual signal. The PL33 is a standard oceanographic 

filter which uses 1/(33 hours) as the cutoff frequency, and is used primarily to remove tidal 

energy (or all signal energy with periodicity less than 33 hours) from oceanographic time series. 

Some energy leakage can occur near the cutoff frequency using this filtering method; however, 

this effect is minimal because the significant diurnal (and higher frequency) tides had been 

removed prior to this step. The low-passed time series was termed the subtidal signal. 

 The subtidal signal was subtracted from the previous residual signal, resulting in a highfrequency time series containing all non-tidal currents having periods less than approximately 

33 hours. This high-frequency signal (typically referred to as noise) contained significant 

energy, which can be due to several sources, including actual flow field turbulence, waveinduced flow, as well as possible data contamination due to mooring motions. The highfrequency signal was saved as a separate time series for later analysis and comparison. 

 The subtidal signal then was reduced further into distinct frequency bands. The first 

frequency band was defined as processes with time scales of 1 to 15 days. It was assumed to 

include wind-driven flows, as well as other processes of similar time scales, such as buoyancydriven flow from Chesapeake Bay observed by Boicourt (1973). Infragravity motions are 

included in this frequency band as well, with time scales of approximately 1 to 14 days. These 

motions have been shown to play a significant but secondary role to cross-shelf currents in this 

region (Wright et al., 1994). This wind-driven band was expected to yield significant energy 

(Madsen et al., 1993; Berger et al., 1995; Savidge and Bane, 2001). The signal was derived by 
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high-pass filtering the subtidal signal with a 15-day cutoff, and was termed the wind-driven 

signal, on the assumption most of the energy within this band results from wind forcing. 

 The second time band defined frequencies with the periodicity greater than 15 days. It 

was termed the low-frequency band and includes seasonal and slightly higher frequency 

processes. This series was derived by subtracting the wind-driven signal from the subtidal 

signal. 

 Each time series was extracted in sequential manner from the raw signal to a set of 

individual process-specific signals, each representing the dominant current occurring at specific 

time scales. This separation procedure was repeated for each data set. Separating these 

processes from the whole illustrated the relative contribution of each to total observed 

circulation at a selected sand borrow site. The signal variance of each resulting time series 

represents its energy level. Comparing the variance of each process to the total signal variance 

yields a representation of how much energy the process contributed to the whole. 

5.1.1.3 Current Components 

Tidal Currents 

 Cross-shelf tides were predominantly semi-diurnal, dominated by the M2 lunar semidiurnal tide. Cross-shelf amplitudes range from a minimum of approximately 3 cm/sec directed 

onshore to a maximum of 9 cm/sec offshore. Along-shelf tidal currents were as often up-shelf 

as down-shelf, reaching an amplitude of 13 cm/sec. Tides in the along-shelf direction were 

mixed diurnal, which is consistent with previous studies (Berger et al., 1995). 

 The analysis revealed that tidal currents affect cross-shelf flow processes at the surface 

greater than along-shelf processes, but influence near-bottom tidal current components equally. 

Although tidal flow possessed a higher fraction of cross-shelf energy in the upper water column 

measured by the ADCP and the MMB, tides only contained about 5% of the total cross-shelf 

energy (Figure 5-3). Tides were the least important process in along-shelf and cross-shelf 

directions. 

High-Frequency Currents 

 High-frequency currents were defined as all non-tidal oscillations having periods less than 

approximately 33 hours, and can result from flow turbulence, responses to localized wind stress, 

measurement noise, and other random motions of the water column. In shallow water, highfrequency processes tend to contribute a greater fraction to the overall current energy than in 

deep water. 

 The standard deviation of cross-shelf high-frequency currents was about 3 to 4 cm/sec, 

meaning that at any time, the currents vary typically by 3 to 4 cm/sec. The standard deviation of 

along-shelf flow was about 4 to 6 cm/sec. High-frequency currents contributed approximately 

13% of the total cross-shelf variance, 5% of along-shelf variance at the surface, and 10% of 

along-shelf variance near-bottom (Figure 5-3). The data reveal some correlation between highfrequency currents and subtidal wind-driven currents, suggesting that these high-frequency 

currents result from wind stress forcing. 
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Figure 5-3. Histogram showing the relative energy (variance) of separated current components; highfrequency, tides, wind-driven, and low-frequency flows. Units are (cm/sec)2

. Along-shelf 

wind-driven currents contained the most energy at the surface and near-bottom for both time 

periods. 

Wind-Driven Currents 

 Wind-driven currents contributed most significantly to the observed currents, containing 

almost 60% of the total along-shelf current variance (Figure 5-3). At the surface, the along-shelf 

current variance was more than three times that near the bottom, accounting for as much as 

57% of the total energy. Wind-driven currents accounted for approximately 50% of the crossshelf energy. 

 The variability of wind-driven along-shelf surface currents during summer months (May to 

September 1997) is nearly twice the variability of wind-driven surface currents from October to 

December. Summer surface currents contain more than 10 times the energy of near-bottom 

currents. This energy gradient indicates a stratification of the water column suitable to upwelling 

and downwelling events. On the North Carolina shelf, northeast winds are favorable for 

downwelling (onshore surface flow and offshore bottom flow), and southwest winds produce 

upwelling (offshore surface flow and onshore bottom flow). From May to September, wind 

speeds were weaker on average (less than 15 m/s) but more consistent in direction, blowing out 

of the northeast 20% of the time and out of the southwest 20% of the time (Figure 5-4). In 
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Figure 5-5, an upwelling event on May 15, 1997 is depicted by a positive cross-shelf surface 

current and negative near-bottom current in response to a south-southwest wind; along-shelf 

flow was relatively weak. As wind shifts from south to north, circulation patterns of coastal 

currents reverse. This is most clearly seen in the downwelling event on May 21 in response to a 

northeast wind. The southward flowing buoyant coastal plume from Chesapeake Bay is 

enhanced by northeast winds (Wright et al., 1986). Pulsing winds from May 21 to 23 out of the 

north-northeast generated strong down-shelf currents reaching 80 cm/s. The inclusion of 

density-driven processes in the 1 to 15 day frequency band increases the percentage of winddriven energy in along-shelf currents during summer months. 

 During winter months (October to December), winds were distributed relatively evenly 

from southwest clockwise to northeast (Figure 5-4). North-northeast wind speeds occasionally 

reached 20 m/s. Turbulent mixing has been observed beginning in fall and during winter storms 

off the coast of North Carolina (Wright et al., 1986). During the strong northeast wind event on 

October 19, the water column responded relatively uniformly at the surface and near-bottom 

(Figure 5-6). Offshore-directed currents reach speeds of 30 cm/s, and along-shelf currents flow 

southerly exceeding 50 cm/s. The strong correlation seen between northeast winds and 

currents during this event is consistent with the literature regarding wind-driven processes on 

the North Carolina shelf (Berger et al., 1995). Observations by Savidge and Bane (2001) 

indicate winds lead transport by half a day or less, and our analysis shows peak wind speeds 

appear to lead peak currents by approximately 6 hours. 

Low-Frequency Currents 

 Low-frequency currents were not well-resolved because the records were relatively short 

(i.e., only a few low-frequency cycles were included in each record). Low-frequency values 

included the mean current. On average, mean flow was southerly in the along-shelf direction, 

flowing at 15 cm/sec near the surface and 5 cm/sec near the seafloor. Mean cross-shelf 

currents were positive (directed onshore) throughout the water column during most of the time 

periods analyzed. Mean cross-shelf flows were approximately 2 to 4 cm/sec, strongest at the 

surface. 

 Low-frequency variance ranged from 17 to 21% of the total in the along-shelf direction; 

low-frequency variance ranged from 12 to 22% in the cross-shelf direction. The variance 

magnitudes show that low-frequency currents in the along-shelf direction are at least three times 

more energetic than cross-shelf flow. 

 

 Figure 5-4. Winds measured at the end of the FRF pier in Duck, NC at an elevation of 19.36 m (NGVD) 

presented in rose diagrams for three time periods. 
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Figure 5-5. Time series of wind speed and direction, and the subtidal component of cross-shelf and 

along-shelf currents, for a two-week period in May 1997. 

Figure 5-6. Time series of wind speed and direction, and the subtidal component of cross-shelf and 

along-shelf currents, for a two-week period in October 1997. 
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5.1.2 Summary of Flow Regimes at Offshore Borrow Sites 

 The analysis presented above suggests along-shelf currents possess higher energy than 

cross-shelf flows. The mean along-shelf flow was directed southward. Along-shelf currents 

were dominated by wind-driven processes, accounting for as much as 60% of the total current 

energy. Wind-driven flows appeared strongly biased by singular events, either local responses 

to storm winds, or non-locally generated buoyant flows, that influenced the magnitude of winddriven current energy. 

 Although wind-driven currents were less significant in the cross-shelf direction, the largest 

percentage of cross-shelf energy existed in the wind-driven frequency band. On average, 

cross-shelf currents were directed offshore. Wave groups and long waves inducing infragravity 

motions may further contribute to cross-shore current variability. It has been suggested that 

these motions can be as often onshore as offshore (Wright et al., 1991). 

 Previous studies indicate that outflow from the Chesapeake Bay exerts significant 

influence on current patterns in this region (e.g., Beardsley and Boicourt, 1981). Density-driven 

flows likely dominate along-shelf surface currents during the May to September time period and 

enhance the effects of upwelling-favorable winds. Currents, which appear dominated by winddriven processes, would be stronger during time periods of higher wind activity occurring from 

October to December. In addition to wind-driven currents, high-frequency (noise, random 

motions) and low-frequency currents also appear to be stronger during winter months (Figure 

5-7). This suggests that high- and low-frequency flow processes may be coupled to 

atmospheric forcing. 

 Data synthesized in this analysis, and supported by previous studies, suggest that shelf 

flow is strongest during high-energy wind events, and that near-bottom currents are oriented 

along the shelf (positive alongshore currents oriented 340°). Wind-driven, near-bottom currents 

were oriented along-shelf nearly 40% of the time during the two periods analyzed (Figure 5-7). 

This evidence suggests that singular events, with corresponding higher currents, have the 

greatest potential to transport sand. If so, sediment transport patterns may be predominately in 

the along-shelf direction, with a net transport oriented in the direction of mean flow. Based on 

the variability analysis, low-frequency (mean) flows are predominantly southwestward (Figure 

5-7). Data also showed that cross-shelf currents were affected by northeast wind events, 

driving downwelling during summer months and offshore flow of the uniform water column 

during fall and winter. Strong wind events forcing near-bottom offshore flows suggest that 

cross-shelf sediment transport due to currents may be net offshore. 

5.2 OFFSHORE SEDIMENT TRANSPORT 

 Infilling rates for each borrow site were computed based on a method outlined in Madsen 

(1987), which relies on earlier work described by Grant and Madsen (1986) for wave-current 

interaction in the bottom boundary layer outside the surf zone. 

 On the continental shelf, currents are driven by a combination of forces resulting from 

winds, tides, and atmospheric pressure gradients. Surface waves also create currents on the 

sea bottom. These wave-induced currents are oscillatory and fluctuate with the passing of each 

wave. In Grant and Madsen (1986), the interaction of wave-induced currents (high-frequency) 

and background currents with longer timescales (low-frequency) is modeled. This analysis 

provides a method for estimating the combined wave-current friction factor (fcw), which is 

necessary for computing sediment transport at a borrow site. 
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Figure 5-7. Rose diagrams of wind, wind-driven currents, and low-frequency currents during two time 

periods in 1997: May to September and October to December. 
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5.2.1 Determining Bottom Transport and Infilling Rates 

 As outlined in Madsen (1987), the net transport qnet at the sea bottom in the presence of 

waves is computed as the averaged instantaneous transport q(t) over the cycle of a wave period 

T, 

( ) ∫ = T

net qs t dt

T q

0

1 . (5.1) 

The instantaneous value of sediment transport is computed using a formula given by Madsen 

(1987) which is based on an earlier empirical relationship known as the Einstein-Brown formula 

(Brown, 1950) for bottom sediment transport in steady unidirectional flow. The Einstein-Brown 

relationship gives the dimensionless transport rate φ as a function of the Shields parameter Ψ, 

3 φ = 40Ψ . (5.2) 

The Shields parameter is used as an indicator of incipient sediment motion, and is the ratio of 

the shear force τ acting on bottom sediment to the submerged weight of grains. The Shields 

parameter is expressed as 

s ρgd

τ

( −1)

Ψ = (5.3) 

where s is the sediment specific gravity, ρ is the density of water, g is the acceleration of gravity, 

and d is the sediment grain diameter. The shear stress is a function of the bottom friction factor, 

f, and the magnitude of the fluid velocity U at the sediment bed. It is expressed as 

2

2

1

τ = fρU . (5.4) 

A critical value for the Shields parameter is determined using the Shields diagram, which 

defines the point of incipient sediment motion based on the boundary Reynolds number. For 

instantaneous values of the Shields parameter that are less than the critical value, no sediment 

motion will occur. 

Therefore, during portions of the wave period that sediment motion does occur, the 

instantaneous dimensional sediment transport rate, expressed in a similar form as equation 

(5.2) is 

( ) [ () ()] 3 2 2

( 1)

0.5













−

+ = s gd

f u t v t

q t c wd cw

q ρ

ρ (5.5) 

where w is the fall velocity of sediment, cq is a constant, fcw is the combined wave-current friction 

factor, and u and v are the velocity components that result from the combination of highfrequency (wave driven) and low-frequency (atmospheric and tide driven) currents. 

A method for computing fcw is given by Madsen (1987), which is essentially an iterative method 

that modifies the bottom boundary layer based on interaction with waves. Initially, the wave 

friction factor, fwc, for waves in the presence of currents is determined by using the equation 
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log 0.17

4 /

1 log 4 /

1

+ = − ω

μ

μ μ s

b

wc wc k

C u

f C f C

 (5.6) 

where ks is a characteristic bottom roughness, ω is the wave radian frequency (2π/T), ub is the 

magnitude of the velocity under the wave (in linear wave theory ub(t)=sin[kx – σt]), and the 

coefficient Cμ is described as 

( )1/ 2 2 Cμ = 1+ 2μ cosθ c + μ (5.7) 

where 

2

*

*















 =

wm

c

u

u

μ (5.8) 

and θc is the angle between the wave approach and the current direction, u*c is the current shear 

velocity, and u*wm is the magnitude of the maximum wave shear velocity in the presence of 

currents. In this procedure, an initial guess for the value of μ must be made, because u*wm is 

initially not known. 

The final value of fcw is computed using the equation 

2

* 2 













 =

r

c

cw u

u f (5.9) 

where u*c is the current shear velocity, and ur is the magnitude of the measured current, 

measured at a particular height above bottom, zr. The current shear velocity is determined by 

the equation 















 = +

* 0

* * ln ln

κ u z

u z u

u cw

m

c

cw

c r

r

δ

δ ; for zr > δ cw (5.10) 

which is quadratic in u*c, and 

2 2

* 2

1 wm wcub u = f , (5.11) 

2

*

2

u*m = Cμu wm , (5.12) 

ω

δ m

cw

uκ * = , (5.13) 

where, 

u*wm = magnitude of the maximum wave shear velocity in the presence of currents, 
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fwc = wave friction factor, for waves in the presence of currents, 

u*m = combined wave-current shear velocity, 

δcw = wave bottom boundary layer thickness, 

u*m = combined wave-current shear velocity, and 

κ = von Karman’s constant (=0.4). 

 A computer program was developed using the relationships of Grant and Madsen (1986) 

for the purpose of computing infilling rates at a borrow site. This program uses wave model 

output (Section 4.0) with current data to determine bottom sediment transport potential at the 

perimeter of the borrow site and a resulting annualized volume rate of sediment that will enter 

the borrow site. 

5.2.2 Model Input Data 

 Wave data from STWAVE model runs and ADCP current data collected offshore the FRF 

provided input conditions for determining borrow site infilling rates. Wave data were extracted 

from the nine existing condition model runs at the perimeter nodes of each borrow site. These 

are the same STWAVE model runs used to determine sediment transport potential at the 

coastline (Section 4.0). Wave model input conditions are listed in Table 5-1. A year-long ADCP 

current record, collected in 13 m water depth, provided direction and magnitude data at the 

ocean surface. Currents were binned by eight compass sectors for input to the bottom transport 

potential model. A listing of surface current inputs used to determine infilling rates is provided in 

Table 5-2. 

 In addition to wave and current inputs, other data and parameters were specified for each 

bottom transport potential model run performed for each borrow site. Depths at each perimeter 

node were taken from the wave model grid. Bottom sediment characteristic grain sizes (d90 and 

d50) also were specified individually for each site. Parameters used for the model runs at each 

borrow site are listed in Table 5-3. 

Table 5-1. Wave model input conditions used to compute offshore sediment transport 

potential. STWAVE model output, from each modeled condition, and at 

each borrow site perimeter grid node was used as input into wave-current 

interaction model used to determine bottom sediment transport potential. 

Wave 

Period 

Band 

Direction Bin Peak Wave 

Direction, θp 

Hmo 

Wave 

Height 

Mean Wave 

Period, Tp 

Percent 

Occurrence 

 (grid relative) (deg. true north) (m) (sec) 

0 to 30 1 1.1 5.1 9.4 

30 to 60 21 1.9 6.0 8.1 

60 to 90 56 1.5 6.7 8.7 

90 to 120 86 1.2 7.4 10.1 

120 to 150 106 0.9 7.6 16.3 

Band 1 

150 to 180 131 0.6 4.6 8.1 

60 to 90 66 1.9 11.5 6.0 

90 to 120 71 1.5 12.8 19.2 

Band 2 

120 to 150 101 1.3 11.3 6.3 
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Table 5-2. Surface currents used for modeling bottom sediment transport and the 

determination of borrow site infilling rates. Current data from Duck FRF 

13 m ADCP, using one-year record from Jan 1997 to Jan 1998. 

Compass Sector 

Current 

Magnitude 

(cm/sec) 

Mean Current 

Direction 

(deg. true north) 

Percent 

Occurrence 

337.5 to 22.5 26.6 3.6 26.5 

22.5 to 67.5 19.2 38.9 9.6 

67.5 to 112.5 11.6 88.8 3.2 

112.5 to 157.5 14.7 140.6 6.1 

157.5 to 202.5 41.7 175.5 43.3 

202.5 to 247.5 14.3 219.4 4.2 

247.5 to 292.5 9.8 269.1 2.4 

292.5 to 337.5 15.2 320.3 4.6 

Table 5-3. Borrow site characteristic depths and bottom sediment 

grain sizes used as bottom sediment transport potential 

model input. 

Borrow Site Average Bottom 

Depth (m) 

Bottom Sediment

d90 (mm) 

Bottom Sediment 

d50 (mm) 

1 17.6 0.85 0.41 

2 16.4 0.90 0.38 

3 east 20.0 0.42 0.21 

3 west 18.7 0.45 0.27 

4 20.2 0.83 0.36 

5.2.3 Infilling Model Results 

 Infilling rates computed for each of the five North Carolina borrow sites represent the total 

potential transport magnitude into each of the sites (Table 5-4). These results likely represent 

an upper bound for sediment transport at each site. Site 2 has the greatest infilling volume rate, 

which is the result of a combination of factors, including its shallow depth relative to the other 

sites and its large perimeter. Because the site is in relatively shallow water, wave-induced 

currents and background currents are large and more sediment is mobile in the proximity of the 

borrow site. Sites that have a larger perimeter generally will trap more sediment over a given 

period. Site 3 east has an infilling rate that is similar to Site 4, even though the area at Site 3 is 

approximately 70% larger. However, Site 3 is located in slightly deeper water. 

 Total infilling times presented in the last column of Table 5-4 were computed using the 

total design excavated volume divided by the computed infilling rates, and therefore represent 

the length of time required to fill a site that is excavated to the total design depth during a single 

dredging event. Site 1 has the longest total infilling time, resulting from the large volume 

extracted from this site and the moderate infilling volume rate. Site 3 west has the shortest 

infilling time due to its small excavation volume, even though it has the smallest infilling rate of 

all five sites. 
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Table 5-4. Characteristic dimensions, computed borrow site infilling rates, and 

estimated time to fill based on total proposed excavated volume. 

Borrow 

Site 

Site 

Perimeter 

(m2

) 

Excavated 

Volume 

(MCM) 

Average 

Perimeter 

Depth (m) 

Annualized 

Infilling 

Volume 

(m3

/yr) 

Computed 

Infilling 

Time (yr) 

1 2.4 x 106 7.2 17.6 73,150 98 

2 2.0 x 106 5.8 16.4 123,160 47 

3 east 0.7 x 106 1.4 20.0 38,270 37 

3 west 0.8 x 106 2.5 18.7 45,970 54 

4 1.2 x 106 2.3 20.2 38,420 60 
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6.0 BIOLOGICAL FIELD SURVEYS 

6.1 BACKGROUND 

 Two field surveys for biological characterization provided environmental data in and 

around four sand resource areas offshore North Carolina. The surveys were conducted in May 

and September 1998. Infaunal, epifaunal, demersal fish, and sediment grain size samples, 

sediment profile images (SPIs), and water column data were collected. The following sections 

provide the methods, results, and discussion for the biological field surveys. 

 Sample types and numbers for the May 1998 Survey 1 and September 1998 Survey 2 are 

summarized in Table 6-1. Sampling locations are illustrated in Figures 6-1 through 6-5. 

6.2 METHODS 

6.2.1 Survey Design 

 The primary objective of the North Carolina field surveys in May and September 1998 was 

to characterize benthic ecological conditions (i.e., infauna, sediment grain size, and epifauna) in 

four sand resource areas (Figure 6-1). Supporting data collected in the areas consisted of 

water column profiles. A secondary objective was to obtain descriptive data on infauna and 

sediment grain size in adjacent areas. 

 The total numbers of samples by type that originally were proposed for Surveys 1 and 2 

were as follows: 

Sample Type Survey 1 (May 1998) Survey 2 (Sep 1998) 

Infauna 

Sediment Profiling Camera 50 stations 

(2 images/station) 

25 stations 

(2 images/station) 

Smith-McIntyre Grab 20 stations 

(1 grab/station) 

50 stations 

(1 grab/station) 

Sediment Grain Size 

Smith-McIntyre Grab 20 stations 

(1 grab/station) 

50 stations 

(1 grab/station) 

Epifauna 

Mongoose Trawls 4 transects 

(1 transect/area) 

4 transects 

(1 transect/area) 

Water Column 

Hydrolab Profiles 4 stations 

(1 station/area) 

4 stations 

(1 station/area) 

 The following sampling rationale pertains to Survey 1 in May 1998 and Survey 2 in 

September 1998. The sampling plan for Surveys 1 and 2 is summarized in Table 6-1. This 

table lists the surface areas, water depths, and numbers of stations by sample type for each of 

the sand resource areas and adjacent stations. 
122

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Table 6-1. Sampling plan for the North Carolina May 1998 Survey 1 and September 1998 Survey 2. 

Number of Stations 

Smith-McIntyre Grab Sediment Profiling 

Camera Grain Size Infauna Epifaunal Trawls Hydrolab 

Sand 

Resource 

Area 

(1,2,3,4)/

Adjacent 

Station 

(R1, R2) 

Surface Area 

(million sq ft) 

and Percent 

of Total 

Water Depth 

(m) 

Survey 1 Survey 2 Survey 1 Survey 2 Survey 1 Survey 2 Survey 1 Survey 2 Survey 1 Survey 2 

1 558 

42% 

15-24 20 11 8 20 8 20 1 1 1 1 

2 153 

11% 

13-22 5 2 2 5 2 5 1 1+1=2 1 1+1=2 

3 367 

27% 

16-24 13 7 5 13 5 13 1 1 1 1 

4 260 

20% 

16-24 10 3 3 10 3 10 1 1 1 1 

R1 24 1 1 1 1 1 1 0 0 0 0 R2 22 1 1 1 1 1 1 0 0 0 0 

Total Number of Stations 48 + 2 = 50 23 + 2 = 25 18 + 2 = 20 48 + 2 = 50 18 + 2 = 20 48 + 2 = 50 4 5 4 5 
123

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MMS Study 2000-056 Figure 6-1. Sampling locations for Adjacent Stations R1 and R2 relative to the four sand resource areas and the North Carolina coast. 
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Figure 6-2. Sampling locations for North Carolina Sand Resource Area 1. 
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Figure 6-3. Sampling locations for North Carolina Sand Resource Area 2. 
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Figure 6-4. Sampling locations for North Carolina Sand Resource Area 3. 
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Figure 6-5. Sampling locations for North Carolina Sand Resource Area 4. 
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6.2.1.1 Infauna and Sediment Grain Size 

Survey 1 (May 1998) 

 To determine the number of infaunal and sediment samples to collect in each area during 

the May 1998 Survey 1, the surface area and percent of the total surface area for each of the 

sand resource areas were calculated (Table 6-1). The percent of the total surface area for each 

of the sand resource areas then was multiplied by the total number of stations originally 

proposed for the project, resulting in the number of samples per sand resource area. 

 The next step was to determine the placement of the infaunal (sediment profiling camera 

and Smith-McIntyre grab) and sediment grain size stations within each area to characterize 

existing assemblages. The goal in placement of the sediment profiling camera stations was to 

provide broad spatial and depth coverage within the sand resource areas and, at the same time, 

ensure that the samples would be independent of one another to satisfy statistical assumptions. 

To accomplish this goal, a systematic sampling approach was used to provide broad spatial and 

depth coverage of the target populations. This approach can, in many cases, yield more 

accurate estimates of the mean than simple random sampling (Gilbert, 1987). Grids were 

placed over figures of each sand resource area. The number of grid cells was determined by 

the number of samples per area. One sampling station then was randomly placed within each 

grid cell of each sand resource area. Randomizing within grid cells eliminates biases that could 

be introduced by unknown spatial periodicities in a sampling area. 

 This systematic sampling approach resulted in designation of 50 locations (48 in the 

4 sand resource areas plus one at each of 2 adjacent stations) for the sediment profiling camera 

stations. All station locations then were pre-plotted on geodetically corrected maps. 

 Attention then was directed to selection of areas for infaunal and sediment grain size 

sampling using a Smith-McIntyre grab. Whereas 50 stations were proposed for sediment 

profiling camera sampling, 20 stations were proposed for infaunal and sediment grain size 

sampling using a Smith-McIntyre grab. Because the purpose of the grab samples was to 

maximize interpretation of the sediment profiling camera data, it was desirable to collect the 

grab samples at the same stations as the sediment profiling camera. Maps of the sand 

resource areas with the 50 sediment profiling camera stations were analyzed and 20 stations 

were selected (18 in the 4 sand resource areas plus one at each of 2 adjacent stations). Due to 

the limited number of grabs per area, grab stations were manually selected to maximize spatial, 

depth, and habitat considerations. 

Survey 2 (September 1998) 

 Placement of infaunal and sediment grain size stations for the September 1998 Survey 2 

was determined based on post-plots and results of the infaunal and sediment grain size stations 

actually sampled during the May 1998 Survey 1. The rationale originally was to sample 

previously sampled stations for seasonal comparisons during future analyses, and further 

investigate areas of heterogeneity. With the disturbance to the sand resource areas from 

Hurricane Bonnie during late August 1998, resampling of previously sampled stations became a 

priority to attempt detection of storm effects. 

 For Survey 2, 25 sediment profiling camera stations were proposed. Twenty of these 

sediment profiling camera stations occupied the same locations as the 20 Smith-McIntyre 

infaunal stations during Survey 1 because these stations were originally selected to maximize 

spatial, depth, and habitat considerations. The remaining 5 of the 25 sediment profiling camera 

stations were located to further characterize areas of heterogeneity (Stations 2, 5, and 17 in 

Sand Resource Area 1, and Stations 5 and 6 in Area 3). 
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 During Survey 2, 50 Smith-McIntyre infaunal stations and 50 Smith-McIntyre sediment 

grain size stations also were sampled. The locations of the 50 Smith-McIntyre infaunal stations 

and 50 Smith-McIntyre sediment grain size stations were identical to each other so that resulting 

grain size data could be used to interpret the infaunal data. These 50 Smith-McIntyre stations 

for Survey 2 were in the same locations as the 50 sediment profiling camera stations for Survey 

1 to enable comparisons between the May and September data. 

6.2.1.2 Epifauna 

 Trawls were towed to cover as wide a depth range within a sand resource area as 

possible within the limits of the length of a trawl tow. During Survey 1, one trawl transect was to 

be made in each of the four sand source areas. This was accomplished for all of the areas 

except Sand Resource Area 2. During Survey 1, the trawl for Area 2 was taken just outside the 

perimeter of Area 2. During Survey 2 in September 1998, a trawl transect was made along a 

line that was close to the line of Area 2 during Survey 1 in May 1998 for comparative purposes. 

In addition, a trawl was taken inside the boundaries of Area 2. 

6.2.1.3 Water Column 

 A water column profile was made at the beginning point of each trawl transect prior to 

actual trawling. Parameters measured were temperature, salinity, dissolved oxygen, and depth. 

When survey results are discussed later, the terms “(in)” and “(out)” are used to distinguish 

whether the trawl and water column profiles were taken inside or outside of Area 2, for reasons 

stated in the preceding paragraph. 

6.2.2 Field Methods 

6.2.2.1 Vessel 

 The May and September field surveys were conducted aboard the R/V WEATHERBIRD 

based in Beaufort, NC. The May field survey took place from 27 to 30 May 1998, and the 

September field survey took place from 14 to 16 September 1998. 

6.2.2.2 Navigation 

 A differential global positioning system (DGPS) was used to navigate the survey vessels 

to all sampling stations. The DGPS was connected to an on-board computer equipped with 

Hypack Navigation Software Version 6.4 (Coastal Oceanographics, 1996). With this system, 

ship position was displayed in real-time on a monitor affixed to a counter top in the wheel house. 

All sampling stations were pre-plotted and stored in the Hypack program. While in the field, the 

actual positions of all samples collected were recorded and stored by the program. 

6.2.2.3 Water Column 

 Temperature, salinity, dissolved oxygen, and depth were measured with a portable 

Hydrolab unit. The Hydrolab was calibrated as needed each working day. Hydrolab 

measurements of temperature (°C), salinity (ppt), and dissolved oxygen (mg/L) were taken at 

1.5-m intervals from the surface to bottom. The Hydrolab was fastened to a weighted line then 

lowered to depth by hand. All measurements were recorded on standard data sheets. 
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6.2.2.4 Sediment Grain Size 

 One grab sample was taken with a Smith-McIntyre grab at each pre-plotted sediment 

sampling station. Once a sample was deemed acceptable (i.e., adequate penetration and 

undisturbed surface layer), a sub-sample of sediment (about 250 g) was removed with a 5-cm 

diameter acrylic core tube and placed in a labeled plastic bag for grain size analyses. This 

sample was stored at 4°C (i.e., on ice). 

6.2.2.5 Sediment Profiling Camera 

 Two replicate images were taken at each pre-plotted station; each SPI replicate is 

identified by the time recorded on the film and on disk along with vessel position. Even though 

multiple images were taken at each location, each image was assigned a unique frame number 

by the data logger and cross-checked with the time stamp in the navigational system’s computer 

data file. Redundant sample logs were kept by the field crew. At the beginning of each survey 

day, the time on the camera's internal data logger was synchronized with the internal clock on 

the computerized navigation system being used to conduct the survey. 

 Test exposures were fired on deck at the beginning and end of each roll of film to verify 

that all internal electronic systems were working to design specifications and to provide a color 

standard against which final film emulsion could be checked for proper color balance. After 

deployment of the camera at each station, the frame counter was checked to make sure that the 

requisite number of replicates had been taken. In addition, a prism penetration depth indicator 

on the camera frame was checked to verify that the optical prism had actually penetrated the 

bottom to a sufficient depth to acquire a profile image. If images were missed (frame counter 

indicator), additional replicates were taken. Because of the paucity of fine-grained sediments in 

the study area, all available prism weights (total of 114 kg) were kept in the camera for the 

entire survey to maximize the camera’s prism penetration. 

6.2.2.6 Infauna 

 One grab sample was taken with a Smith-McIntyre grab at each pre-plotted sediment 

sampling station. Once a sample was deemed acceptable (i.e., adequate penetration and 

undisturbed surface layer), a sub-sample of sediment was removed for grain size analyses, then 

the remainder of the grab sample was sieved through 0.5-mm sieve for infaunal analyses. The 

infaunal sample was placed in a container and preserved in 10% formalin with rose bengal 

stain. 

6.2.2.7 Epifauna and Demersal Fishes 

 A 7.6-m mongoose trawl was towed for 10 min (bottom time) along the pre-plotted 

transects. The tow path of each trawl tow was logged into the Hypack navigation system. Once 

the trawl was on deck, the contents of the catch bag were sorted, then identified to the lowest 

practical taxon. All organisms were identified and returned to the sea. Identifications were 

recorded on standard trawl data sheets. 

6.2.3 Laboratory Methods 

6.2.3.1 Sediment Grain Size 

 Sediment grain size analyses were conducted using combined sieve and hydrometer 

analyses according to recommended American Society for Testing Materials (ASTM) 

procedures. Grain size samples were washed in demineralized water, dried, and weighed. 

Coarse and fine fractions (sand/silt) were separated by sieving through a U.S. Standard Sieve 
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Mesh No. 230 (62.5 μm). Sediment texture of the coarse fraction was determined at half-phi 

intervals by passing the sediment through nested sieves. The weight of the materials collected 

in each particle size class was recorded. Boyocouse hydrometer analyses were used to 

analyze the fine fraction (<62.5 μm). 

6.2.3.2 Sediment Profiling Camera 

 After the color slides were developed, the images were scanned and stored in Kodak 

Photo-CD format. All digital images were analyzed using image analysis software. Calibration 

information was determined by measuring 1-cm graduations from the Kodak Color Separation 

Guide. This calibration information was applied to all images analyzed. Linear and area 

measurements were recorded as number of pixels and converted to scientific units using the 

calibration information. Measured parameters were recorded on an electronic spreadsheet. A 

quality assurance/quality control person checked all data prior to the final interpretation. 

 Parameters measured from sediment profiling camera images collected included the 

following: 

• Sediment type (grain size major mode and range); 

• Camera prism penetration depth; 

• Small-scale surface boundary roughness; 

• Thickness of depositional layers; 

• Mud clasts (presence and diameter); 

• Apparent redox potential discontinuity (RPD) depth; 

• Infaunal successional stage; and 

• Organism-Sediment Index (OSI). 

 A detailed explanation of how these measurements were performed and their 

interpretation is provided below. 

Sediment Type 

 Sediment grain size major mode and range were visually estimated from the photographs 

by overlaying a grain size comparator that was at the same scale. This comparator was 

prepared by photographing a series of Udden-Wentworth size classes (equal to or less than 

coarse silt up to granule and larger sizes) with the sediment profiling camera. Seven grain size 

classes were on this comparator: 4 phi, 4 to 3 phi, 3 to 2 phi, 2 to 1 phi, 1 to 0 phi, 0 to -1 phi, 

and < -1 phi. The lower limit of optical resolution of the photographic system was about 62 μm, 

allowing recognition of grain sizes equal to or greater than coarse silt (> 4 phi). The accuracy of 

this method has been documented by comparing SPI estimates with grain size statistics 

determined from laboratory sieve analyses. 

 The comparison of the images with Udden-Wentworth sediment standards photographed 

through the SPI optical system also was used to map near-surface stratigraphy such as sandover-mud and mud-over-sand. When mapped on a local scale near facies boundaries, this 

stratigraphy can provide information on transport directions. 

Camera Prism Penetration Depth 

 The sediment profiling camera prism penetration depth was measured from the bottom of 

the image to the sediment-water interface. Average penetration depth was determined by 

measuring across the entire cross-sectional image. Linear maximum and minimum depths of 
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penetration also were measured. Maximum, minimum, and average penetration depths were 

recorded in the data file. 

 Prism penetration is potentially a noteworthy parameter; because the number of weights 

used in the camera was held constant throughout this survey, the camera functioned as a staticload penetrometer. Comparative penetration values from stations with similar grain size give an 

indication of the relative water content of the sediment. Highly bioturbated sediments and 

rapidly accumulating sediments tend to have the highest water contents and greatest prism 

penetration depths. 

 The depth of the camera's penetration into the bottom also reflects the bearing capacity 

and shear strength of local sediments. Over-consolidated or relic sediments and shell-bearing 

sands resist camera penetration. Highly bioturbated, sulfitic, or methanogenic muds are the 

least consolidated, and deep penetration is typical. Seasonal changes in camera prism 

penetration are typically observed at the same station and are related to the control of sediment 

geotechnical properties by bioturbation (Rhoads and Boyer, 1982). The effect of water 

temperature on bioturbation rates appears to be important in controlling both biogenic surface 

relief and prism penetration depth (Rhoads and Germano, 1982). 

Small-Scale Surface Boundary Roughness 

 Surface boundary roughness was determined by measuring the vertical distance (parallel 

to the film border) between the highest and lowest points of the sediment-water interface. 

Surface boundary roughness (sediment surface relief) measured over a horizontal distance of 

15 cm typically ranges from 0.02 to 3.8 cm and may be related to either physical structures 

(ripples, rip-up structures, mud clasts) or biogenic features (burrow openings, fecal mounds, 

foraging depressions). Biogenic roughness typically changes seasonally and is related to the 

interaction of bottom turbulence and bioturbational activities. 

 The camera must be level to take accurate boundary roughness measurements. In 

sandy sediments, boundary roughness can be a measure of sand wave height. On silt-clay 

bottoms, boundary roughness values often reflect biogenic features such as fecal mounds or 

surface burrows. 

Thickness of Depositional Layers 

 Because of the camera's unique design, SPI can be used to detect the thickness of 

depositional and dredged material layers. SPI is effective in measuring layers ranging in 

thickness from 20 cm (the height of the SPI optical window) to 1 mm. During image analyses, 

the thickness of newly deposited sedimentary layers can be determined by measuring the linear 

distance between the pre- and post-disposal sediment-water interface. Recently deposited 

material usually is evident because of its unique optical reflectance and/or color relative to the 

underlying material representing the pre-disposal surface. Also, in most cases, the point of 

contact between the two layers and a textural change in sediment composition in the new layer 

are clearly visible, facilitating measurement of the thickness of the newly deposited layer. 

Mud Clasts 

 When fine-grained, cohesive sediments are disturbed, either by physical bottom scour or 

faunal activity (e.g., decapod foraging), intact clumps of sediment often are scattered about the 

seafloor. These mud clasts can be seen at the sediment-water interface in the images. During 

analyses, the numbers of clasts were counted, the diameters of typical clasts were measured, 

and their oxidation states were assessed. The abundance, distribution, oxidation state, and 
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angularity of mud clasts can be used to make inferences about the recent pattern of seafloor 

disturbance in an area. 

 Depending on their place of origin and the depth of disturbance of the sediment column, 

mud clasts can be reduced or oxidized (in the images, the oxidation state is apparent from the 

reflectance value; see the following subsection titled Apparent Redox Potential Discontinuity 

Depth). Also, once at the sediment-water interface, these mud clasts are subject to bottomwater oxygen levels and currents. Based on laboratory microcosm observations of reduced 

sediments placed within an aerobic environment, oxidation of reduced surface layers by 

diffusion alone is quite rapid, occurring within 6 to 12 hours (Germano, 1983). Consequently, 

the detection of reduced mud clasts in an obviously aerobic setting suggests a recent origin. 

The size and shape of the mud clasts also are revealing. Mud clasts may be moved and broken 

by bottom currents and animals (macro- or meiofauna; Germano, 1983). Over time, large 

angular clasts become small and rounded. 

Apparent Redox Potential Discontinuity Depth 

 Aerobic near-surface marine sediments typically have higher reflectance values relative to 

underlying hypoxic or anoxic sediments. Surface sands washed free of mud also have higher 

optical reflectance than underlying muddy sands. These differences in optical reflectance are 

readily apparent in the images; oxidized surface sediment contains particles coated with ferric 

hydroxide (an olive or tan color when associated with particles), while reduced and muddy 

sediments below this oxygenated layer are darker, generally gray to black. The boundary 

between the colored ferric hydroxide surface sediment and underlying gray to black sediment is 

called the apparent RPD. 

 The depth of the apparent RPD in the sediment column is an important time-integrator of 

dissolved oxygen conditions within sediment porewaters. In the absence of bioturbating 

organisms, this high reflectance layer (in muds) typically will reach a thickness of 2 mm 

(Rhoads, 1974). This depth is related to the supply rate of molecular oxygen by diffusion into 

the bottom and the consumption of that oxygen by the sediment and associated microbiota. In 

sediments that have very high sediment oxygen demand (SOD), the sediment may lack a high 

reflectance layer even when the overlying water column is aerobic. 

 In the presence of bioturbating macrofauna, the thickness of the high reflectance layer 

may be several centimeters. The relationship between the thickness of this high reflectance 

layer and the presence or absence of free molecular oxygen in the associated porewaters must 

be assumed with caution. The actual RPD is the boundary (or horizon) that separates the 

positive Eh region of the sediment column from the underlying negative Eh region. The exact 

location of this Eh = 0 potential can be determined accurately only with microelectrodes; hence, 

the relationship between the change in optical reflectance, as imaged with the sediment profiling 

camera, and the actual RPD can be determined only by making the appropriate in situ Eh 

measurements. For this reason, the optical reflectance boundary, as imaged, was described in 

this study as the “apparent” RPD and it was recorded as a mean value. In general, the depth of 

the actual Eh = 0 horizon will be either equal to or slightly shallower than the depth of the optical 

reflectance boundary. This is because bioturbating organisms can mix ferric hydroxide-coated 

particles downward into the bottom below the Eh = 0 horizon. As a result, the apparent mean 

RPD depth can be used as an estimate of the depth of porewater exchange, usually through 

porewater irrigation (bioturbation). Biogenic particle mixing depths can be estimated by 

measuring the maximum and minimum depths of imaged feeding voids in the sediment column. 

This parameter represents the particle mixing depths of head-down feeders (mainly 

polychaetes). 
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 The rate of depression of the apparent RPD within the sediment is relatively slow in 

organic-rich muds (on the order of 200 to 300 μm per day); therefore this parameter has a long 

time constant (Germano and Rhoads, 1984). The rebound in the apparent RPD also is slow 

(Germano, 1983). Measurable changes in the apparent RPD depth using the SPI optical 

technique can be detected over periods of 1 or 2 months. This parameter is used effectively to 

document changes (or gradients) that develop over a seasonal or yearly cycle related to water 

temperature effects on bioturbation rates, seasonal hypoxia, SOD, and infaunal recruitment. In 

sediment profile surveys of ocean disposal sites sampled seasonally or yearly throughout New 

England (performed under the Disposal Area Monitoring System Program for the USACE, New 

England Division), frequent monitoring with SPI technology repeatedly has documented a 

drastic reduction in apparent RPD depths at disposal sites immediately after dredged material 

disposal. This reduction was followed by a progressive post-disposal deepening of the apparent 

RPD (barring further physical disturbance). Consequently, time series RPD measurements can 

be a critical diagnostic element in monitoring the degree of recolonization in an area by the 

ambient benthos. 

 Apparent mean RPD depth also can be affected by local erosion. Peaks of disposal 

mounds commonly are scoured by divergent flow over mounds. This scouring can wash away 

fines and shell or gravel lag deposits, and can result in a very thin apparent RPD depth. During 

storm periods, erosion may completely remove any evidence of the apparent RPD (Fredette et 

al., 1988). 

 Another important characteristic of the apparent RPD is the contrast in reflectance values 

at this boundary. This contrast is related to the interactions among the degree of organic 

loading, the bioturbational activity in the sediment, and the levels of bottom-water dissolved 

oxygen in an area. High inputs of labile organic material increase SOD and, subsequently, 

sulfate reduction rates (and the abundance of sulfide end products). This results in more highly 

reduced (lower-reflectance) sediments at depth and higher RPD contrasts. In a region of 

generally low RPD contrasts, images with high RPD contrasts indicate localized sites of 

relatively high past inputs of organic-rich material such as organic or phytoplankton detritus, 

dredged material, and sewage sludge. 

Infaunal Successional Stage 

 Information concerning infaunal successional stages in fine-grained sediments may be 

collected with SPI technology. These stages are recognized in the images by the presence of 

dense assemblages of near-surface polychaetes and/or subsurface feeding voids; both may be 

present in the same image. The concept of successional stages is based on the theory that 

organism-sediment interactions follow a predictable sequence after a major seafloor 

perturbation. This theory states that primary succession results in “the predictable appearance 

of macrobenthic invertebrates belonging to specific functional types following a benthic 

disturbance. These invertebrates interact with sediment in specific ways. Because functional 

types are the biological units of interest ... our definition does not demand a sequential 

appearance of particular invertebrate species or genera” (Rhoads and Boyer, 1982). This 

theory is formally developed in Rhoads and Germano (1982) and Rhoads and Boyer (1982). 

 This continuum of change in animal communities after a disturbance (primary succession) 

has been divided arbitrarily into three stages: Stage I is the initial community of tiny, densely 

populated polychaete assemblages; Stage II is the start of the transition to head-down deposit 

feeders; and Stage III is the mature community of deep-dwelling, head-down deposit feeders. 

 After an area of bottom is disturbed (whether from natural or anthropogenic events), the 

first invertebrate assemblage (Stage I) appears within days after the disturbance. Stage I 
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consists of dense assemblages of tiny tube-dwelling marine polychaetes that reach population 

densities of 104

 to 106 individuals per m2. These animals feed at or near the sediment-water 

interface and physically stabilize or bind the sediment surface by producing a mucous “glue” 

that they use to build their tubes. Sometimes deposited dredged material layers contain Stage I 

tubes still attached to mud clasts from their location of origin; these transported individuals are 

considered as part of the in situ fauna in the assignment of successional stages. 

 If there are no repeated disturbances to the newly colonized area, then these initial tubedwelling suspension or surface-deposit feeding taxa are followed by burrowing, head-down 

deposit-feeders that rework the sediment deeper over time and mix oxygen from the overlying 

water into the sediment. Animals in these later-appearing communities (Stage II or III) are 

larger, have lower overall population densities (10 to 102

 individuals per m2), and can rework 

sediments to depths of 3 to 20 cm or more. These animals “loosen” the sedimentary fabric, 

increase the water content in the sediment (thereby lowering the sediment shear strength), and 

actively recycle nutrients because of the high exchange rate with the overlying waters resulting 

from their burrowing and feeding activities. 

Organism-Sediment Index 

 The OSI is a summary statistic that is calculated on the basis of four independently 

measured SPI parameters: apparent mean RPD depth, infaunal successional stage, presence 

of methane gas, and low/no dissolved oxygen at the sediment-water interface. Table 6-2 shows 

how these parameters are summed to derive the OSI. 

Table 6-2. Calculation of the Organism-Sediment Index based on sediment profile 

image parameters. 

Parameter Index Value 

A. Apparent Mean RPD Depth (choose one) 

 0.00 cm 0 

 >0 to 0.75 cm 1 

 0.76 to 1.50 cm 2 

 1.51 to 2.25 cm 3 

 2.26 to 3.00 cm 4 

 3.01 to 3.75 cm 5 

 >3.75 cm 6 

B. Infaunal Successional Stage (choose one) 

 Azoic -4 

 Stage I 1 

 Stage I → II 2 

 Stage II 3 

 Stage II → III 4 

 Stage III 5 

 Stage I on III 5 

 Stage II on III 5 

C. Chemical Parameters (choose one or both if appropriate) 

 Methane present -2 

 Low/no dissolved oxygena -4 

Organism-Sediment Index = Total of above subset indices (A+B+C) 

Range: -10 to +11 

a This parameter is not based on a Winkler or polarigraphic electrode measurement, but on the imaged 

evidence of reduced, low reflectance (i.e., high-oxygen-demand) sediment at the sediment-water 

interface. 
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 The highest possible OSI value is +11, which reflects a mature benthic community in 

relatively undisturbed conditions (generally a good yardstick for high benthic habitat quality). 

These conditions are characterized by deeply oxidized sediment, with a low inventory of 

anaerobic metabolites and low SOD, and by the presence of a Stage III community. OSI values 

of 6 or less indicate that the benthic habitat has experienced physical disturbance, 

eutrophication, or excessive bioavailable contamination in the recent past. The lowest possible 

OSI value is -10, which indicates that the sediment has a high inventory of anaerobic 

metabolites, has a high oxygen demand, and is azoic. 

6.2.3.3 Infauna 

 Formalin-preserved infaunal samples were rinsed on a U.S. Standard No. 30 (0.59-mm) 

sieve and transferred to 70% isopropanol. Before sorting, samples were passed through a 

series of sieves (0.3, 0.5, 0.6, 1, and 2 mm) to separate the organisms into size classes. 

Samples were sorted by hand under dissecting microscopes. All sediment in each sample was 

examined by a technician who removed all infauna observed. Organisms were identified to 

lowest practical taxon and counted. A minimum of 10% of all samples were resorted by 

different technicians as a quality control measure. Voucher specimens of each taxon were 

archived at the Barry A. Vittor & Associates, Inc. laboratory. 

6.2.4 Data Analysis 

6.2.4.1 Water Column 

 Temperature, salinity, dissolved oxygen, and depth values were entered into an electronic 

spreadsheet and tabulated. Depth profiles were plotted for temperature-salinity and 

temperature-dissolved oxygen. 

6.2.4.2 Sediment Grain Size 

 A computer algorithm was used to determine size distribution and provide interpolated 

size information for the fine fraction at 0.25-phi intervals. Percentages of gravel, sand, silt, and 

clay were calculated and recorded along with a Folk’s description for each sample. 

6.2.4.3 Sediment Profiling Camera 

 See Section 6.2.3.2 Laboratory Methods. 

6.2.4.4 Infauna 

 Summary statistics including number of taxa, number of individuals, density, diversity 

( H′), evenness ( J ′ ), and species richness (D) were calculated for each sampling station. 

Diversity ( H′), also known as Shannon’s Index (Pielou, 1966), was calculated as follows: 

H = - pi ln( pi) i=1

S

′ ∑

where S is the number of taxa in the sample, i is the ith taxa in the sample, and pi is the number 

of individuals of the ith taxa divided by (N) the total number of individuals in the sample. 

 Evenness ( J ′ ) was calculated with Pielou’s (1966) index of evenness: 
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( ) S

Η J = ln

′ ′

where H′ is Shannon’s index as calculated above and S is the total number of taxa in a 

sample. 

 Species richness (D) was calculated by Margalef’s index: 

(N)

(S - 1) D = ln

where S is the total number of taxa in the sample, and N is the number of individuals in the 

sample. 

 Spatial and temporal patterns in infaunal assemblages were examined with cluster 

analysis. Cluster analyses were performed on similarity matrices constructed from raw data 

matrices consisting of taxa and samples (station – survey). Only species-level taxa, with the 

exception of two species complexes that can be only reliably identified to genus, were included 

in the analyses. Of these taxa, only those contributing at least 0.1% of the total abundance of 

species level taxa were included. Raw counts of each individual infaunal taxon in a sample (n) 

were transformed with the log10(n+1) transformation prior to similarity analysis. Both normal 

(stations) and inverse (taxa) similarity matrices were generated using the Bray-Curtis index that 

was calculated using the following formula: 

∑

∑

+ =

i

ij ik

i

ij ik

jk x x

x x

B

( )

2 min( , )

where Bjk (for normal analysis) is the similarity between samples j and k; xij and xik are the 

abundances of species i in samples j and k. B ranges from 0.0 when two samples have no 

species in common to 1.0 when the distribution of individuals among species is identical 

between samples. For inverse analysis, the Bjk is the similarity between species j and k; xij and 

xik are the abundances of species j and k in sample i. 

 Normal similarity matrices were clustered using the group averaging method of clustering, 

and inverse similarity matrices were clustered using the flexible sorting method of clustering 

(Boesch, 1973). Flexible sorting was performed with β = -0.25, a widely accepted value for this 

analysis (Boesch, 1973). 

 The extent to which sample groups formed by normal cluster analysis of the entire data 

set could be explained by environmental variables such as sediment grain size parameters was 

examined by canonical discriminant analysis (SAS Institute Inc., 1989). Canonical discriminant 

analysis identifies the degree of separation among predefined groups of variables in multivariate 

space. This analysis examined the relationships among the environmental variables and the 

station groups as indicated by the normal cluster analysis. 

6.2.4.5 Epifauna and Demersal Fishes 

 Raw counts of individual epifaunal and demersal fish taxa were tabulated by sand 

resource area for both field surveys. 
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6.3 RESULTS 

6.3.1 Water Column 

 Raw data for water column profiles made during Survey 1 are provided in Appendix C2, 

Table C2-1. Depth profiles of temperature-salinity and temperature-dissolved oxygen for the 

May 1998 Survey 1 are shown in Figures 6-6 and Figures 6-7. Temperature profiles showed 

similar patterns of gradual decrease from surface to bottom within all four areas. Surface 

temperatures varied little among areas and ranged from 19.4°C in Area 4 to 21.3°C in Areas 1 

and 3. Bottom temperatures ranged from 13.1°C in Area 4 to 13.4°C in Area 1. Surface salinity 

generally increased rapidly to about 5 m then gradually increased to near-bottom waters, except 

in Area 3 where salinity decreased just below the surface then increased to near-bottom waters. 

Surface salinities ranged from 21.8 ppt in Area 2(out) to 28.3 in Area 4. Bottom salinities 

ranged from 32.6 ppt in Area 1 to 33.1 ppt in Area 4. Dissolved oxygen profiles generally 

decreased from surface to bottom. Surface dissolved oxygen values ranged from 8.22 mg/L in 

Area 4 to 8.61 mg/L in Area 2(out). Bottom dissolved oxygen values ranged from 7.36 mg/L in 

Area 3 to 7.88 mg/L in Area 4. 

Raw data for water column profiles made during Survey 2 are given in Appendix C2, 

Table C2-2. Temperature, salinity, and dissolved oxygen profiles made during the September 

1998 Survey 2 are shown in Figures 6-8 and 6-9 (the water column profile made outside of Area 

2 [see Section 6.2.1] was not plotted, but the raw data are in Table C2-2). Water column 

temperature was generally uniform within all of the sand resource areas, decreasing much less 

from surface to bottom during the September survey as compared to the May survey. Surface 

temperatures ranged from 24.0°C in Areas 1 and 3 to 24.4°C in Area 2(in). Salinity profiles 

deviated little from vertical lines, unlike the May profiles. Surface salinity ranged from 26.1 ppt 

in Area 3 to 31.9 ppt in Area 2(in). Bottom salinities ranged from 27.0 ppt in Area 2(out) to 

32.4 ppt in Area 4. Dissolved oxygen values decreased slightly from surface to bottom with the 

exception of Area 3. Surface dissolved oxygen values ranged from 6.74 mg/L in Area 1 to 

7.18 mg/L in Area 2(out). Bottom dissolved oxygen values ranged from 3.71 mg/L in Area 3 to 

5.95 mg/L in Area 2(out). In general, dissolved oxygen values for all areas were lower during 

the September survey than during the May survey. 

6.3.2 Sediment Grain Size 

Sediment grain size of Smith-McIntyre grab samples taken in the sand resource areas 

during the May 1998 Survey 1 consisted mostly of sand (Appendix C3, Table C3-1). Eighteen of 

the 20 samples were composed of greater than 92% sand. In Sand Resource Area 1, all but 

one sample contained greater than 92% sand; the remaining sample was composed of 77% 

sand and 22.5% gravel. Both samples collected in Area 2 contained greater than 92% sand. In 

Area 3, four of five samples contained greater than 92% sand; the remaining sample contained 

75% sand and 24% gravel. All three samples from Area 4 contained greater than 97% sand. 

Single samples from each of the two adjacent stations contained 98% and 97% sand. 

 General patterns of grain size composition in the grab samples taken during the 

September 1998 Survey 2 were similar to the patterns seen during the May 1998 Survey 1 

(Appendix C3, Table C3-2). Sand characterized most grab samples with 42 of 50 grab samples 

containing greater than 95% sand. In Sand Resource Area 1, 14 of 20 samples contained 

greater than 95% sand. The remaining six samples contained mostly sand; in five of these 

samples, gravel made up most of the non-sand proportions (ranging from 8% to 13%); in the 

other sample, silt (8%) and clay (30%) composed most of the non-sand fraction. This was 
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Figure 6-6. Temperature and salinity profiles recorded by Hydrolab during the May 1998 survey in the 

four sand resource areas offshore North Carolina. 

Temperature

Salinity

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

Salinity (ppt)

20 25 30 35

Area 3

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

Salinity (ppt)

20 25 30 35

Area 4

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

Salinity (ppt)

20 25 30 35

Area 2

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

Salinity (ppt)

20 25 30 35

Area 1
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Figure 6-7. Temperature and dissolved oxygen profiles recorded by Hydrolab during the May 1998 

survey in the four sand resource areas offshore North Carolina. 

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

D.O. (mg/L)

0 5 10

Area 4

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

D.O. (mg/L)

0 5 10

Area 2

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

D.O. (mg/L)

0 5 10

Area 1

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

D.O. (mg/L)

0 5 10

Area 3

Temperature

Dissolved Oxygen
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Figure 6-8. Temperature and salinity profiles recorded by Hydrolab during the September 1998 survey in 

the four sand resource areas offshore North Carolina. 

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

Salinity (ppt)

20 25 30 35

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

Salinity (ppt)

20 25 30 35

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

Salinity (ppt)

20 25 30 35

Temperature

Salinity

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

Salinity (ppt)

20 25 30 35

Area 1 Area 2

Area 3 Area 4
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Figure 6-9. Temperature and dissolved oxygen profiles recorded during the September 1998 survey in 

the four sand resource areas offshore North Carolina. 

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

D.O. (mg/L)

0 5 10

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

D.O. (mg/L)

0 5 10

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

D.O. (mg/L)

0 5 10

Temperature (°C)

0 5 10 15 20 25

Water Depth (m)

0

5

10

15

20

25

D.O. (mg/L)

0 5 10

Temperature

Dissolved Oxygen

Area 1 Area 2

Area 3 Area 4
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the only sample collected during the September 1998 Survey 2 that contained appreciable 

proportions of silt and clay. All five samples collected in Area 2 contained greater than 99% 

sand. In Area 3, 11 of 13 samples contained greater than 98% sand; gravel composed 35% 

and 21% of the non-sand fractions of the two remaining samples. All 10 samples from Area 4 

contained greater than 95% sand. The adjacent stations each contained 99% sand. 

6.3.3 Sediment Profiling Camera 

 Sediment profiling camera images were collected during both field surveys. Data from the 

Survey 1 images are in Appendix C4, Table C4-1. Data from the Survey 2 images are in 

Appendix C4, Table C4-2. 

6.3.3.1 Area 1 

 During May, 20 SPI stations were sampled in Area 1, in water depths ranging from 15 m 

(the shallowest station sampled in the survey) to 23 m, representing almost the total range of 

water depths sampled in the entire survey (Adjacent Station R1 in 24 m was the deepest station 

sampled in the May survey). Sediments throughout this area were fairly uniform, with stations 

showing a grain size major mode primarily of either very fine sand (4 to 3 phi) or fine sand (3 to 

2 phi). Bedforms were evident in almost every image collected from this area, indicating a fairly 

high-energy bottom kinetic regime. Variation in sediment grain size major mode (Figure 6-10) 

did not correspond with water depth, but more likely represented whether the profile image was 

collected on the upcurrent or downcurrent flank of the bedform (Figure 6-11). 

 While a small number of images (8 out of 40) showed poorly-sorted sediments (Figure 6-

12), most stations were represented by a total grain size range in the sand-sized fraction with 

sediments that were well-sorted (Figure 6-13). Evidence of bedload transport was apparent at 

Stations 17 and 20, where rippled, coarse-sediment surface layers showed distinct contact 

boundaries with underlying finer sands (Figure 6-14). Small-scale surface boundary roughness 

values ranged from 0.4 cm (Station 5) to 6.31 cm (Station 13; Figure 6-15); surface roughness 

elements were caused by the physical forces (bottom currents, wave energy) that created the 

sand ripples present at the sediment-water interface. 

 Sediment profiling camera prism penetration across the area ranged from a low of 2.2 cm 

in one of the replicate images from Station 9 to a maximum of 7.7 cm in one of the replicate 

images from Station 20 (Figure 6-16). Variation in prism penetration from station to station 

within the study area did not follow any distinct pattern, nor was it correlated with either 

sediment grain size major mode (Figure 6-10) or water depth. 

 Evidence of infaunal invertebrate activity was present at most of the stations in the form of 

either large, distinct burrows (Figure 6-17), large polychaete tubes projecting above the 

sediment-water interface (Figure 6-18), or more subtle subsurface burrow structures or faunal 

appendages (Figure 6-19). One quarter of the stations sampled (Stations 1, 6, 9, 16, and 20) 

had no clear evidence of substantial infaunal reworking activity, although the high sediment 

water content at Station 20 is most likely due to intense infaunal bioturbation. One of the 

images from Station 8 showed an intact surface layer of diatoms present (Figure 6-20) that 

would serve to stabilize the sediment surface and make it more resistant to erosion and 

transport. With the exception of the distinct tubicolous fauna at Stations 2 and 9 and the large 

burrows at Station 5, the remaining 12 stations that did show evidence of infaunal activity 

(subsurface burrow network) had sedimentary structures similar enough that one would infer 

infaunal community composition to be fairly uniform among these stations. 

 
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Figure 6-10. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) and camera prism 

penetration depth (Survey 1) based on sediment profiling in North Carolina Sand Resource 

Area 1. 
145

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MMS Study 2000-056 Figure 6-11. a. Sediment profile image from Station 14, Area 1, May 1998, Survey 1 showing the presence of bedforms and a grain size major mode of 3 to 2 phi (image width represents 15 cm). b. Sediment profile image from Station 15, Area 1, May 1998, Survey 1 showing the presence of bedforms and a grain size major mode of 4 to 3 phi (image width represents 15 cm). 

a

b
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Figure 6-12. Sediment profile image from Station 16, Area 1, May 1998, Survey 1 showing poorly-sorted 

sediments with shell hash not only on the sediment surface but admixed down to a depth of 

7 cm (image width represents 15 cm). 
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Figure 6-13. Sediment profile image from Station 6, Area 1, May 1998, Survey 1 showing well-sorted 

sediments in the very-fine-to-fine-sand range; note the hermit crab on the sediment surface 

(image width represents 15 cm). 
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Figure 6-14. Sediment profile image from Station 17, Area 1, May 1998, Survey 1 showing a distinct 

demarcation between the coarse surface layer and underlying fine sands (image width 

represents 15 cm). 
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Figure 6-15. Sediment profile image from Station 13, Area 1, May 1998, Survey 1; boundary roughness 

values from all images in Area 1 were primarily due to surface relief from the physical forces 

that created the sand ripples present throughout the area (image width represents 15 cm). 
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Figure 6-16. Sediment profile image from Station 20, Area 1, May 1998, Survey 1; note that grain size is 

similar to that of other images, but prism penetration is greater, which is a function of 

lowered sediment shear strength (image width represents 15 cm). 
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Figure 6-17. Sediment profile image from Station 5, Area 1, May 1998, Survey 1 showing an extensive 

network of subsurface burrow structures created by errant infauna (image width 

represents15 cm). 
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Figure 6-18. Sediment profile image from Station 2, Area 1, May 1998, Survey 1 showing tubicolous 

polychaetes projecting above the sediment-water interface (image width represents 15 cm). 
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Figure 6-19. Sediment profile image from Station 3, Area 1, May 1998, Survey 1 with thin, white 

polychaete palp (arrow) being retracted back to the animal, which is below prism penetration 

depth (image width represents 15 cm). 
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Figure 6-20. Sediment profile image from Station 8, Area 1, May 1998, Survey 1; the darker areas on the 

sediment surface are mats of benthic diatoms (image width represents 15 cm). 
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 During the September survey, 11 SPI stations were sampled in Area 1 (Figure 6-10). 

Sediments were uniformly sandy with modal grain sizes of 4 to 3 phi in most images. Two 

images from Station 8 and one image from Station 20 had modal grain sizes of 3 to 2 phi. 

Boundary roughness ranged from 0.34 to 3.02 during this survey. Prism penetration ranged 

from 1.31 to 6.37 cm. 

 Most images collected from Area 1 during the September survey revealed some biotic 

activity, including infaunal burrows (Figure 6-21), surficial fecal casts, and megafaunal burrows. 

Of the 22 images examined from the area, only 3 images indicated infaunal successional 

stages: Stage I in one image from Station 5, and Stage III in one image from Station 1 and one 

image from Station 5. 

6.3.3.2 Area 2 

 Area 2 was the smallest of the four areas surveyed. Only five SPI stations were sampled 

in Area 2 during the May 1998 survey from water depths ranging from 15 to 19 m. As in Area 1, 

sediments were well-sorted and very uniform throughout the area, with a grain size major mode 

ranging from fine sand (3 to 2 phi) in the northern half of the area to very fine sand (4 to 3 phi) in 

the southern half of the area (Figure 6-22). Bedforms also were evident at every location 

sampled (Figure 6-23). Sediment profiling camera prism penetration ranged from a low of 

3.1 cm at Station 5 to a maximum of 6.0 at Station 2 (Figure 6-22); as in Area 1, penetration 

depth did not vary consistently either with grain size major mode or with water depth. 

 While organic concentrations in the sediments appeared to be rather low, judging from 

optical reflectance signatures, there was evidence of a thin layer (1 to 3 mm) deposit of organic 

material on the sediment surface at Station 4 (Figure 6-24). Structural evidence of faunal 

activity was different than in Area 1; the infaunal community in Area 2 appeared to consist of 

larger-sized individuals than those found in Area 1 as evidenced by the presence of large fecal 

casts on the sediment surface at three stations (Stations 2, 3, and 4; Figure 6-25). 

 The two SPI stations (Stations 2 and 4) sampled during the September survey (Figure

6-22) exhibited modal grain sizes of 3 to 2 phi and 4 to 3 phi, respectively. Prism penetration 

ranged from 3.1 to 6.0 cm. 

 There was evidence of infaunal activity noted among the images. One image 

(Figure 6-26) from Station 4 was assigned infaunal successional Stage III. A crab was present 

in one image (Figure 6-27), but epifauna was not prevalent in the images. 

6.3.3.3 Area 3 

 Area 3 had the widest range of sediment types of the four areas sampled, based on 

13 SPI stations surveyed during May 1998 in water depths ranging from 16 to 23 m. While most 

of these 13 stations had a sediment grain size major mode of very fine sand (4 to 3 phi), there 

was a line of stations (Stations 2, 4, 5, and 6) that varied dramatically in grain size, with grain 

size major mode shifting up or down from station to station (Figure 6-28). These abrupt shifts 

were not correlated with depth; for example, Stations 6 and 7 were in similar water depths (21.0 

and 21.3 m, respectively), but sediment type differed dramatically (coarse sand and shell hash 

at Station 6, very fine sand at Station 7; Figure 6-29). Station 5 had unique sediment major 

mode and stratigraphy; it was the only station in this survey that had a thin surface layer 

(approximately 4 cm) of fine sand covering a silt-clay (>4 phi) substratum (Figure 6-30). 

 Camera prism penetration depth was similar to the other areas surveyed, ranging from a 

minimum of 2.2 cm to a maximum of 6.2 cm. The small variability in prism penetration did not 

correlate with sediment type or grain size major mode. 
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Figure 6-21. Sediment profile image from Station 2, Area 1, September 1998, Survey 2 showing surface 

roughness elements caused by infaunal burrowing activity; the crater-like rim of a large 

burrow opening can be seen in the left background of the image (image width represents 

15 cm). 
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Figure 6-22. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) and camera prism 

penetration depth (Survey 1) based on sediment profiling in North Carolina Sand Resource 

Area 2. 
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Figure 6-23. Sediment profile image from Station 1, Area 2, May 1998, Survey 1 showing the presence of 

bedforms and a grain size major mode of 4 to 3 phi (image width represents 15 cm). 
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Figure 6-24. Sediment profile image from Station 4, Area 2, May 1998, Survey 1 showing a thin surface 

deposit of fine-grained material with a grain size >4 phi (image width represents 15 cm). 
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Figure 6-25. Sediment profile image from Station 2, Area 2, May 1998, Survey 1; arrows point to fecal 

casts on the sediment surface from infaunal deposit feeders (image width represents 15 cm). 
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Figure 6-26. Sediment profile image from Station 4, Area 2, September 1998, Survey 2; arrows indicate 

traces of linear burrows and places where the camera prism has transected subsurface 

burrow structures (image width represents 15 cm). 
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Figure 6-27. Sediment profile image from Station 2, Area 2, September 1998, Survey 2 showing a crab's 

eyes peering just above the sediment surface at the camera lens (image width represents 

15 cm). 
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Figure 6-28. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) and camera prism 

penetration depth (Survey 1) based on sediment profiling in North Carolina Sand Resource 

Area 3. 
164

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Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 Figure 6-29. a. Sediment profile image from Station 6, Area 3, May 1998, Survey 1 showing the presence of shell fragments and a grain size major mode of 1 to 0 phi (image width represents 15 cm). b. Sediment profile image from Station 7, Area 3, May 1998, Survey 1 showing the presence of bedforms and a grain size major mode of 4 to 3 phi (image width represents 15 cm). 

a

b
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Figure 6-30. Sediment profile image from Station 5, Area 3, May 1998, Survey 1 showing a layer of fine 

sand on top of a silt/clay foundation (image width represents 15 cm). 
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 There was little evidence of infaunal activity at most of the Area 3 stations, most likely due 

to a major mode of very fine sand and resulting limited prism penetration than a true paucity of 

fauna. Station 3 did show evidence at the surface of a feeding depression similar to those 

made by polychaetes of the genus Arenicola (Figure 6-31). Station 2 showed the presence of a 

polychaete assemblage with large tubes constructed of mud and shell fragments projecting 

above the sediment-water interface (Figure 6-32). 

 Although modal sediment types varied among SPI stations during the September survey 

(Figure 6-28), most were very fine sand (4 to 3 phi). The two images from Station 6 differed 

most in modal grain size (2 to 1 phi and 1 to 0 phi), indicating small-scale habitat heterogeneity. 

Prism penetration ranged from 2.2 to 6.2 cm. 

 Some infaunal activity was observed in 9 of 14 images collected during the September 

survey in Area 4. Most of this activity was minimal and only a single image (from Station 10) 

indicated an infaunal successional stage (Stage III). 

6.3.3.4 Area 4 

 During May 1998, 10 SPI stations were sampled in Area 4 in water depths ranging from 

20 to 23 m (Figure 6-33). Sediment grain size major mode was uniform throughout the entire 

area, consisting of very fine sand (4 to 3 phi); bedforms were present throughout the entire area 

(Figure 6-34). Camera prism penetration ranged from 4.0 to 6.7 cm. While average camera 

prism penetration was slightly higher in this area than in the other three areas, none of the areas 

was significantly different from the others in this measure of sediment bearing strength 

(p = 0.07, one-way ANOVA). 

 A surface diatom layer was evident at Station 5 (Figure 6-35). There was minimal 

evidence of subsurface biological activity; except for a shallow infaunal burrow at Station 10 

(Figure 6-36), most images were devoid of apparent infaunal activity. Other than a thin surface 

layer (approximately 1 mm) of fine organic material at Station 7 (Figure 6-37), the crosssectional profile throughout the area resembled very fine beach sand with surface ripples and 

little or no apparent organic matter in the sediment. 

 During September 1998, three stations were sampled with the sediment profiling camera 

(Figure 6-33). The modal sediment type at all stations was very fine sand (4 to 3 phi). Prism 

penetration ranged from 4.42 to 5.93 cm. 

 Some biological activity was present in the images from the September survey, but no 

infaunal successional stages were found. Polychaete tubes and individual bivalves were 

observed at Station 4. Images from Station 9 showed a patchy diatom film. 

6.3.3.5 Adjacent Stations 

 Two adjacent stations were sampled as part of the May survey. Given that only two 

images could be collected at each adjacent station (a total of four images), it is difficult to state 

how representative the images are, considering the relatively dramatic changes in sediment 

grain size that occurred over relatively short distances in Area 3. Given this caveat, even 

though prism penetration was similar to the other four areas, Adjacent Station R2 had a 

noticeably different sediment grain size major mode (2 to 1 phi) as compared to most stations 

sampled (Figure 6-38). 

 During the September survey, modal grain size was very fine sand (4 to 3 phi) at Adjacent 

Station R1. At Adjacent Station R2, modal grain size was 4 to 3 phi in one image and 3 to 2 phi 
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Figure 6-31. Sediment profile image from Station 3, Area 3, May 1998, Survey 1 showing a surface 

feeding pit most likely caused by an infaunal polychaete with a J-shaped tube (image width 

represents 15 cm). 
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Figure 6-32. Sediment profile image from Station 2, Area 3, May 1998, Survey 1 showing an assemblage 

of large tubicolous polychaetes with tubes ornamented with shell fragments (image width 

represents 15 cm). 
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Figure 6-33. Spatial distribution of sediment grain size major mode (Surveys 1 and 2) and camera prism 

penetration depth (Survey 1) based on sediment profiling in North Carolina Sand Resource 

Area 4. 
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Figure 6-34. Sediment profile image from Station 4, Area 4, May 1998, Survey 1 showing a 

representative image of sediment conditions in the entire area; bedforms were present 

throughout this region, and all stations had a grain size major mode of 4 to 3 phi (image 

width represents 15 cm). 
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Figure 6-35. Sediment profile image from Station 5, Area 4, May 1998, Survey 1 showing a surface 

diatom layer (image width represents 15 cm). 
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Figure 6-36. Sediment profile image from Station 10, Area 4, May 1998, Survey 1 showing a shallow 

subsurface burrow at the left side of the image (image width represents 15 cm). 
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Figure 6-37. Sediment profile image from Station 7, Area 4, May 1998, Survey 1 showing a thin 

depositional layer of fine-grained material on a sandy bottom (image width represents 

15 cm). 
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Figure 6-38. Sediment profile image from Adjacent Station 2, May 1998, Survey 1 showing the presence 

of shell fragments and a grain size major mode of 2 to 1 phi (image width represents 15 cm). 
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in the other. Prism penetration was higher at Adjacent Station R2 (4.70 and 5.03 cm) than 

Adjacent Station R1 (2.11 and 3.04 cm). Little biological activity was observed at the adjacent 

stations during the surveys. 

6.3.4 Infauna 

 A phylogenetic list of infauna collected in bottom grabs during the May and September 

1998 surveys is presented in Appendix C5, Table C5-1. Considering both surveys of the sand 

resource areas, 18,176 individuals were collected, representing 179 taxa in 9 separate phyla. 

As a group, infauna were more abundant during the September survey, when an average of 321 

individuals per grab were collected, as compared to, 106 individuals per grab during the May 

survey. Sixty-one taxa (34% of total) were common to both surveys. Of those taxa found in just 

one of the two surveys, 59% (106 taxa) were sampled during the September cruise. The 

archiannelid Polygordius (lowest practical identification level [LPIL]) was numerically dominant 

in the grabs, especially during the September survey, and represented 14% of all infauna 

censused over both surveys. Other than Polygordius, taxa that were among the top 

10 numerical dominants during both the May and September surveys included unidentified 

oligochaetous annelids and the amphipods Acanthohaustorius millsi, Metharpinia floridana, 

Protohaustorius wigleyi, and Pseudunciola obliquua. 

Table 6-3 lists the numerically dominant infaunal taxa sampled from each of the sand 

resource areas and adjacent stations during the May survey. Numerically dominant taxa 

sampled during the May survey included the amphipod P. wigleyi (16.4% of all collected 

individuals), unidentified oligochaetous annelids (6.6%), the polychaete Spiophanes bombyx

(5.2%), the amphipod M. floridana (5.1%), and unidentified haustoriid amphipods (4.6%) 

(Table 6-3). The 10 most abundant taxa collected in grabs during the May survey comprised 

57% of all infaunal individuals during that survey. 

 Numerically dominant taxa collected during the September survey (Table 6-4) were 

Polygordius (15.3% of all individuals collected), the amphipod P. wigleyi (10.5%), unidentified 

cirratulid polychaetes (5.6%), and the amphipods Byblis serrata (4.7%) and P. obliquua (3.8%). 

The 10 most abundant taxa collected in grabs during September (Table 6-4) comprised 55% of 

all infaunal individuals during that survey. 

Table 6-5 presents summary statistics for each of the sand resource areas and adjacent 

stations for the May and September surveys. During the May survey, the mean number of taxa 

sampled per sand resource station was greatest in Areas 1 (21 taxa) and 3 (20), while Area 1 

stations averaged the greatest number of taxa (37) in September. The highest number of 

infaunal taxa collected from a single station was collected at Station 2 in Area 3 (28 taxa) during 

the May survey and at Station 6 in Area 3 (52) during the September survey. Area 4 yielded the 

fewest number of taxa per station during both the May (11 taxa) and September (33) surveys. 

The fewest number of infaunal taxa collected from a single station was collected at Station 4 in 

Area 4 (9) during May and at Station 3 in Area 3 (20) during September. The number of taxa 

yielded by adjacent stations exceeded the averages of each of the sand resource areas during 

May. 

 Highest mean number of individuals per station were sampled from Area 3 (station 

average = 169 individuals) during the May survey, while Area 1 yielded the greatest mean 

abundances (368) in September (Table 6-5). The highest number of individuals collected from 

a single station was sampled from Station 10 in Area 3 (361 individuals) during the May survey 

and from Station 3 in Area 1 (962) in September. Area 2 yielded the lowest mean abundance 

during the May survey (32), while Areas 4 (233) and 2 (234) yielded the lowest mean 
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Table 6-3. Ten most abundant infaunal taxa from samples collected during the May 1998 

Survey 1 in the four sand resource areas (1, 2, 3, and 4) and two adjacent 

stations (R1 and R2) offshore North Carolina.

Area Taxonomic name Count Taxonomic name Count 

Spiophanes bombyx 108 Solenidae (LPIL) 20 

Oligochaeta (LPIL) 97 Spionidae (LPIL) 17 

Metharpinia floridana 80 Spisula solidissima 12 

Haustoriidae (LPIL) 61 Nephtys picta 10 

Tellina (LPIL) 42 Byblis serrata 10 

Apoprionospio pygmaea 29 Lucinidae (LPIL) 6 

Ascidiacea (LPIL) 29 Ostracoda (LPIL) 6 

Polygordius (LPIL) 29 Ampharetidae (LPIL) 5 

Tanaissus psammophilus 28 Nephtyidae (LPIL) 3 

1 

Nephtys bucera 26 

R1 

Aricidea wassi 3 

Protohaustorius (LPIL) 9 Caulleriella sp. J 13 

Protohaustorius wigleyi 6 Protohaustorius wigleyi 11 

Chiridotea tuftsi 4 Metharpinia floridana 9 

Lumbrinerides acuta 4 Byblis serrata 6 

Pseudunciola obliquua 4 Acanthohaustorius millsi 4 

Tellina (LPIL) 4 Bathyporeia parkeri 4 

Bathyporeia parkeri 3 Pseudoleptocuma minor 3 

Haustoriidae (LPIL) 3 Oligochaeta (LPIL) 2 

Rhynchocoela (LPIL) 3 Euspira heros 2 

2 

Gastropoda (LPIL) 2 

R2 

Unciola (LPIL) 2 

Protohaustorius wigleyi 289 Protohaustorius wigleyi 349 

Spio setosa 75 Oligochaeta (LPIL) 140 

Pseudunciola obliquua 62 Spiophanes bombyx 111 

Polygordius (LPIL) 54 Metharpinia floridana 109 

Acanthohaustorius millsi 39 Haustoriidae (LPIL) 98 

Oligochaeta (LPIL) 37 Acanthohaustorius millsi 85 

Exogone rolani 30 Polygordius (LPIL) 84 

Polycirrus sp. G 28 Spio setosa 81 

Haustoriidae (LPIL) 28 Pseudunciola obliquua 76 

3 

Parapionosyllis longicirrata 22 

May 

Total 

Tanaissus psammophilus 75 

Protohaustorius wigleyi 25 LPIL = Lowest practical identification level.

Tanaissus psammophilus 25 

Acanthohaustorius millsi 18 

Metharpinia floridana 8 

Pseudunciola obliquua 7 

Amakusanthura magnifica 6 

Haustoriidae (LPIL) 6 

Protohaustorius (LPIL) 5 

Tellina (LPIL) 4 

4 

Caulleriella sp. J 3 
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Table 6-4. Ten most abundant infaunal taxa from samples collected during the September 

1998 Survey 2 in the four sand resource areas (1, 2, 3, and 4) and two adjacent 

stations (R1 and R2) offshore North Carolina.

Area Taxonomic Name Count Station Taxonomic Name Count 

Polygordius (LPIL) 2033 Byblis serrata 73 

Cirratulidae (LPIL) 477 Ampelisca sp. X 40 

Byblis serrata 340 Apoprionospio pygmaea 34 

Oligochaeta (LPIL) 320 Cirratulidae (LPIL) 23 

Branchiostoma (LPIL) 219 Nephtys picta 19 

Tharyx acutus 206 Tharyx acutus 14 

Rhynchocoela (LPIL) 184 Ampelisca (LPIL) 8 

Protohaustorius wigleyi 167 Spiophanes bombyx 6 

Metharpinia floridana 160 Owenia fusiformis 6 

1 

Apoprionospio pygmaea 143 

R1 

Ostracoda (LPIL) 5 

Pseudunciola obliquua 228 Protohaustorius wigleyi 77 

Acanthohaustorius millsi 115 Metharpinia floridana 54 

Polygordius (LPIL) 78 Nephtys picta 27 

Metharpinia floridana 70 Byblis serrata 26 

Protohaustorius wigleyi 56 Ampelisca bicarinata 25 

Tanaissus psammophilus 49 Apoprionospio pygmaea 20 

Cirratulidae (LPIL) 48 Acanthohaustorius millsi 19 

Rhepoxynius hudsoni 44 Pseudunciola obliquua 18 

Capitella capitata 30 Caulleriella sp. J 9 

2 

Acanthohaustorius shoemakeri 28 

R2 

Unciola irrorata 6 

Protohaustorius wigleyi 960 Polygordius (LPIL) 2452 

Apoprionospio pygmaea 365 Protohaustorius wigleyi 1679 

Nephtys picta 301 Cirratulidae (LPIL) 906 

Cirratulidae (LPIL) 293 Byblis serrata 757 

Polycirrus sp. G 278 Pseudunciola obliquua 616 

Ampelisca bicarinata 200 Apoprionospio pygmaea 589 

Byblis serrata 161 Nephtys picta 571 

Brania wellfleetensis 133 Metharpinia floridana 460 

Acanthohaustorius millsi 121 Acanthohaustorius millsi 455 

3 

Pseudunciola obliquua 119 

Sept. 

Total 

Oligochaeta (LPIL) 391 

Protohaustorius wigleyi 418 LPIL = Lowest practical identification level. 

Polygordius (LPIL) 228 

Pseudunciola obliquua 206 

Acanthohaustorius millsi 144 

Byblis serrata 137 

Metharpinia floridana 123 

Rhepoxynius hudsoni 119 

Tanaissus psammophilus 104 

Tellina agilis 83 

4 

Nephtys picta 72 
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Table 6-5. Summary of infaunal statistics by survey for sand resource areas (1, 2, 3, and 4) and adjacent stations (R1 and R2) 

offshore North Carolina.

May 1998 (Survey 1) 

No. of Taxa No. of Individuals Density (individuals/m2) H' Diversity J' Evenness D Richness Area/ 

Station Mean Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

1 21 4 112 67 1,123 668 2.42 0.33 0.80 0.11 4.49 0.67 2 16 5 32 14 320 141 2.49 0.19 0.92 0.04 4.19 0.89 3 20 7 169 142 1,694 1,417 2.12 0.50 0.73 0.17 3.83 0.95 4 11 2 42 24 420 235 2.04 0.19 0.85 0.06 2.83 0.37 

R1 27 119 1,190 2.81 0.85 5.44 R2 23 69 690 2.66 0.85 5.20 

September 1998 (Survey 2)

No. of Taxa No. of Individuals Density (individuals/m2) H' Diversity J' Evenness D Richness Area/ 

Station Mean Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

Mean 

Per 

Station 

Standard 

Deviation 

1 37 6 368 213 3,685 2,134 2.54 0.44 0.71 0.11 6.22 1.01 2 35 7 234 120 2,344 1,203 2.70 0.41 0.76 0.10 6.39 1.29 3 36 10 350 221 3,503 2,209 2.53 0.30 0.71 0.08 6.20 1.11 4 33 7 233 64 2,334 645 2.58 0.18 0.74 0.05 5.83 1.08 

R1 36 285 2,850 2.68 0.75 6.19 R2 37 339 3,390 2.70 0.75 6.18 
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abundances during September. The fewest number of individuals sampled from a single station 

during the May survey was observed at Station 2 in Area 2 (22 individuals), while the 

September survey yielded its lowest count from Station 3 in Area 3 (57). Infaunal abundance at 

adjacent stations was comparable to average abundances of the sand resource areas during 

both surveys. 

 A summary of infaunal community indices for each sand resource area is included in 

Table 6-5 for the May and September surveys. Mean values of species diversity (H’) and 

species richness (J’) generally were higher in September as compared to May. Species 

evenness (D) was similar during both surveys, and this index was less variable across resource 

areas during September. 

 Stations in Area 2 yielded the highest mean values of species diversity (2.49) and 

evenness (0.92) during May (Table 6-5). During the May survey, the highest measure of mean 

species richness was calculated from Area 1 stations (4.49). The lowest mean values of 

species diversity and richness (2.04 and 2.83, respectively) during the May survey were found 

in Area 4. Mean species evenness was lowest in Area 3 (0.73) during the May survey. During 

September, highest mean values of species diversity, evenness, and richness were found at 

Area 2 (2.70, 0.76, and 6.39, respectively). Lowest mean values of species diversity, evenness, 

and richness were recorded during September from Area 3 (2.53), Area 1 and 3 (0.71), and 

Area 4 (5.83), respectively. 

6.3.4.1 Cluster Analysis 

 Patterns of infaunal similarity among stations were examined with cluster analysis. 

Cluster analyses excluded those taxa that were rare in the samples or that were redundant (i.e., 

had a lowest practical identification level [LPIL] designation), except for the polychaete 

Mediomastus (LPIL) and the archiannelid Polygordius (LPIL). The majority of taxa included in 

the cluster analyses were polychaetes (40 taxa), followed by various crustaceans (23), and 

gastropod (8) and bivalve (4) mollusks. 

 When examined over both surveys, normal cluster analysis produced four groups (Groups 

A through D) of stations (samples) that were similar with respect to species composition and 

relative abundance. Several stations that were not included within any of these 4 station 

groupings, yet were dissimilar enough not to be grouped together, were placed into an outlier 

group (Group X). Group X stations were depauperate in terms of abundance and species 

richness, and included 9 of the 70 stations sampled during the project. Group X was composed 

of samples collected during both surveys, although primarily it included stations sampled during 

May. Station Groups C (13 stations) and D (29 stations) included only samples collected during 

the September survey, while Groups A (2 stations) and B (17 stations) were composed of 

samples from both the May and September surveys. Figure 6-39 shows the geographic 

distribution of infaunal stations grouped by normal analysis. 

 Station Groups A and B were characterized by generally low infaunal abundances. Group 

A stations supported high numbers of taxa that were rare at all other stations, most prominently 

the polychaetes Exogone rolani, Parapionosyllis longicirrata, Polycirrus sp. G, and Spio setosa. 

Group C was distinguished from other station groups primarily by the presence of relatively high 

numbers of the archiannelid Polygordius and the polychaetes Aricidea catherinae, A. cerrutii, 

Brania wellfleetensis, Hesionura elongata, Lumbrinerides acuta, Parougia caeca, and 

Streptosyllis arenae. Group D stations were depauperate with respect to these Group C taxa. 

In addition, Group D stations yielded taxa that were relatively rare in other stations groups, 

including the amphipods Ampelisca sp. X and A. bicarinata, the cumacean arthropod Cyclaspis 
180

Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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MMS Study 2000-056 Figure 6-39. Station groups (A to D, and X) based on normal cluster analysis of infaunal samples collected during the May 1998 Survey 1 and September 1998 Survey 2 in the four sand resource areas and two adjacent stations offshore North Carolina. 

Survey 1

75o37'38.63" W 75o33'36.00" W 75o29'33.37" W

35o47'29.49" N

B

X

B

X

X

XX B

B

B

B

B

A

B

B

B

X

B

X

B

Survey 2

D

C D D

C

C D C

C D

D

D

C

C

X

X

D

CC C

D

B

B

C

B

D

D

D D

D

D

B B

D

A D

D

D

D

D

D

D D

C

D

D C

D

D

D

35o50'47.18" N

35o54'4.86" N

35o57'22.54" N

36o7'15.56" N36o3'57.89" N36o0'40.22" N

75o37'38.63" W 75o33'36.00" W 75o29'33.37" W

35o50'47.18" N35o47'29.49" N

35o54'4.86" N

35o57'22.54" N

36o7'15.56" N36o3'57.89" N36o0'40.22" N
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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181

varians, the gastropod Natica pusilla, and the polychaetes Apoprionospio pymaea and S.

bombyx. 

 Inverse cluster analysis examining both the May and September surveys resulted in four 

groups of taxa (Groups 1 through 4) that reflected their co-occurrence in resource area samples 

(Table 6-6). Many infauna included in the overall cluster analysis were relatively rare and 

heterogeneously distributed; these taxa were not included in the four species groups defined by 

the inverse analysis. Species Group 1 included the most homogeneously distributed taxa found 

during the study, both among the various sand resource areas and among surveys. This group 

included the amphipods A. millsi, M. floridana, P. obliquua and P. wigleyi, the polychaete 

Caulleriella sp. J (= C. cf. killariensis), the bivalve Tellina agilis, the archiannelid Polygordius, 

and the tanaid crustacean Tanaissus psammophilus. Group 2 taxa primarily comprised various 

amphipods, including Acanthohaustrious intermedius, Ampelisca sp. X (= A. cf. verrilli), A. 

bicarinata, B. serrata, Rhepoxynius hudsoni, and Unciola irrorata, and polychaetes, including A. 

pygmaea, Owenia fusiformis, Nephtys picta, S. bombyx, and Tharyx acutus. Species Group 3 

included taxa that predominantly were found at a single Area 3 station during each survey, and 

included mostly polychaetes, including E. rolani, Mediomastus (LPIL), P. longicirrata, Polycirrus

sp. G, and S. setosa. Except for the bivalve Mytilus edulis, Species Group 4 was composed 

entirely of polychaetes, including A. catherinae, A. cerrutii, B. wellfleetensis, Glycera 

dibranchiata, H. elongata, L. acuta, P. caeca, S. arenae, and Scoletoma acicularum. 

Table 6-6. Infaunal species groups resolved from inverse cluster analysis of all samples 

collected during the May 1998 Survey 1 and September 1998 Survey 2 in the 

four sand resource areas and two adjacent stations offshore North Carolina.

GROUP 1 GROUP 3 

Protohaustorius wigleyi Spio setosa

 Pseudunciola obliquua Parapionosyllis longicirrata

 Acanthohaustorius millsi Polycirrus sp. G 

 Tanaissus psammophilus Exogone rolani

 Metharpinia floridana Mediomastus (LPIL) 

 Polygordius (LPIL) Pista quadrilobata

 Caulleriella sp. J Schistomeringos pectinata

 Tellina agilis Scoletoma ernesti

Lysilla alba

GROUP 2 

Tharyx acutus GROUP 4 

 Ampelisca sp. X Pisione remota

 Apoprionospio pygmaea Mytilus edulis

 Byblis serrata Brania wellfleetensis

 Nephtys picta Aricidea catherinae

 Spiophanes bombyx Aricidea cerrutii

 Ampelisca bicarinata Streptosyllis arenae

 Unciola irrorata Lumbrinerides acuta

 Rhepoxynius hudsoni Hesionura elongata

 Owenia fusiformis Parougia caeca

 Acanthohaustorius intermedius Mooreonuphis pallidula

 Turbonilla interrupta Protodorvillea kefersteini

 Pandora inflata Glycera dibranchiata

Scoletoma acicularum

Ampharete acutifrons 

LPIL = Lowest practical identification level.
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182

 Species Group 1 taxa were the most widely distributed among sand resource stations, 

although certain of the Group 1 taxa (amphipods A. millsi, P. obliquua and P. wigleyi) were 

sparse in Station Group C. Sediments at Group C stations tended to contain high gravel 

percentages relative to Group D stations. Only 2 of 29 Group D stations had measurable gravel 

in surficial sediments, otherwise these stations had sand substrata. Species Group 4 included 

taxa that were associated with Station Group C. Species Group 3 was associated primarily with 

Station Group A, which included two stations that had the highest percent gravel of any of the 

sand resource stations. 

6.3.4.2 Canonical Discriminant Analysis 

 Data collected during the two surveys were analyzed using canonical discriminant 

analysis to determine which environmental parameters most affected the abundance and 

distribution of infaunal populations. The first two canonical discriminant variates were used to 

analyze variability among those station groups identified by normal cluster analysis as being 

similar with respect to species composition and relative abundance. The first canonical variate 

(CAN1) correlated best with survey (0.8771). The second canonical variate (CAN2) best 

correlated with the relative percentages of gravel (0.9299) and sand (-0.8030). 

 The selection of any sand resource area as a sediment source for nourishment projects 

will be based partly on its environmental characteristics. Patterns of infaunal similarity among 

stations (normal cluster analysis) and the co-occurrence of taxa within samples (inverse cluster 

analysis) therefore were examined for each sand resource area. The following describes the 

results of this area-by-area analysis for each survey, as well as the affinities of the station 

groups and species groups identified by cluster analyses. Due to the heterogeneity of many 

taxa distributions, generally low abundances, and relatively limited sampling, only well-defined 

species groups generated from the inverse analyses are included in the discussion. 

6.3.4.3 Area 1 

 Normal cluster analysis resulted in five station groups in Area 1 (Groups A through E) that 

were similar with respect to the composition and abundance of infaunal taxa (Table 6-7). Five 

of the Area 1 stations were placed into outlier Group X due to infaunal assemblage dissimilarity 

with one another and with stations composing the five station groupings (A through E). Station 

Group A consisted of a single station from the September survey that yielded high numbers of 

the archiannelid Polygordius and relatively greater densities of taxa that were rare or absent at 

other Area 1 stations, including the bivalves Crenella decussata and M. edulis, and the 

polychaetes G. dibranchiata and P. remota. Station Group B consisted of three stations from 

the May survey that yielded a few sparsely distributed taxa. Station Groups C (12 stations) and 

D (5 stations) composed most of the Area 1 stations during the September survey. Group C 

stations were distinguished from other stations groups primarily by yielding relatively greater 

numbers of the amphipod P. obliquua, bivalve Tellina agilis, and polychaetes A. catherinae, A. 

cerrutii, and B. wellfleetensis. In general, Group C stations yielded greater abundances of the 

archiannelid Polygordius than other Area 1 stations. Group D stations were characterized by 

relatively greater densities of the amphipods Ampelisca sp. X, B. serrata, and U. irrorata, and 

the polychaete A. pygmaea than were other stations. Station Group E included two stations 

during the September survey that yielded relatively low abundances of taxa common in other 

stations during that survey, although this group did yield relatively greater numbers of the 

polychaetes N. picta, Paraprionospio pinnata, and T. acutus. 

 
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Table 6-7. Two-way table from normal (Station Groups X–E) and inverse (Species Groups 1-4a

) cluster analysis of infaunal samples 

collected during the May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand Resource Area 1 (A1) offshore North 

Carolina. Data are presented as total counts for individual taxa.

x A B C D E 

Taxon 

S1-A1-8 S1-A1-6 

S1-A1-10 S1-A1-20 

S1-A1-7 S2-A1-4 S1-A1-1 

S1-A1-16 

S1-A1-9 

S2-A1-11 S2-A1-12 S2-A1-15 S2-A1-10 S2-A1-17 S2-A1-16 S2-A1-13 S2-A1-14 S2-A1-20 

S2-A1-3 S2-A1-7 S2-A1-8 S2-A1-1 

S2-A1-19 

S2-A1-2 

S2-A1-18 

S2-A1-6 S2-A1-5 S2-A1-9 

Apoprionospio pygmaea 0 28 0 0 0 0 0 0 1 0 0 3 0 0 0 0 0 0 0 0 0 6 9 73 0 51 0 1

Ampelisca sp. X 0 0 0 0 0 0 0 0 0 0 2 10 1 3 0 0 0 0 0 1 0 1 42 15 0 47 15 5

Spiophanes bombyx 0 108 0 0 0 0 0 0 0 3 1 6 3 0 0 2 0 1 1 1 0 4 12 2 7 0 0 0

Byblis serrata 0 4 0 0 0 0 8 3 2 1 0 3 3 2 11 11 6 2 2 0 0 88 91 26 42 49 0 3

Nephtys picta 0 0 0 0 0 0 0 0 0 3 2 7 9 1 2 1 0 1 6 1 0 4 3 1 13 19 39 25

Unciola irrorata 0 2 0 0 0 0 0 0 0 0 1 5 0 3 3 0 1 3 5 0 4 11 10 2 4 21 0 11

1 

Rhepoxynius hudsoni 0 0 0 0 0 2 0 0 0 22 6 25 22 12 0 0 0 0 0 0 0 4 5 6 0 0 0 1

Tanaissus psammophilus 0 0 1 2 0 7 1 14 10 13 5 6 6 7 0 0 16 2 0 1 1 0 0 0 0 0 0 0

Protohaustorius wigleyi 0 0 1 0 0 1 3 8 6 5 10 35 0 0 2 0 4 0 0 0 0 0 40 1 39 30 0 0

Acanthohaustorius millsi 0 0 0 0 0 0 7 7 10 0 9 26 2 0 0 0 3 0 0 1 0 2 0 0 13 0 0 0

Caulleriella sp. J 1 0 0 1 2 0 3 3 3 8 9 16 3 13 5 15 12 1 0 2 1 2 6 0 7 5 0 10

Tellina agilis 0 0 0 0 0 0 0 0 1 9 23 9 1 7 2 14 6 2 0 5 12 0 0 0 0 2 0 3

Pseudunciola obliquua 0 1 0 0 0 0 0 1 0 2 3 7 0 5 4 2 8 0 0 0 0 0 0 0 6 7 0 0

Polygordius (LPILb) 0 0 4 1 24 633 0 0 0 47 49 19 244 152 8 94 77 320 178 153 19 4 12 6 4 9 2 3

Metharpinia floridana 0 0 4 0 10 0 32 8 26 0 0 0 0 0 5 27 40 14 51 17 1 2 0 0 2 1 0 0

Spio pettiboneae 0 0 0 0 0 0 0 0 0 0 3 0 1 0 10 1 0 3 0 9 6 0 0 0 17 0 5 8

Tharyx acutus 0 0 0 0 0 0 0 0 0 0 1 2 9 0 1 0 7 0 3 6 16 0 0 32 4 22 103 0

Ilyanassa trivittata 0 0 0 0 0 3 0 0 0 0 0 2 4 1 0 2 3 2 1 0 0 0 5 0 2 1 15 0

2 

Paraprionospio pinnata 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 8 9 

Reticulocythereis sp. A 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 10 0 

Solemya velum 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 0 

Polycirrus eximius 0 0 0 0 0 0 0 0 0 0 0 0 0 0 60 0 0 0 0 0 0 0 0 0 0 0 0 0 

Crepidula fornicata 0 0 0 0 0 0 0 0 0 0 0 0 0 1 16 0 0 1 0 0 0 0 1 2 0 0 0 1 

Turbonilla interrupta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 2 0 0 0 0

Nephtys bucera 2 16 0 0 0 0 7 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Americhelidium americanum 1 0 0 0 0 0 3 1 1 0 0 0 0 1 0 0 0 0 2 1 0 0 0 0 0 1 0 1

Aricidea wassi 0 0 0 0 0 0 6 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 0 0 0 0

Protohaustorius sp. B 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cirrophorus lyra 6 0 6 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ophelia denticulata 1 0 4 4 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ampharete acutifrons 0 0 0 0 0 0 0 0 0 0 0 0 3 4 0 0 1 0 3 0 0 2 0 0 0 0 0 1

Capitella capitata 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 3 0 0 0 0 0 0 5 0 0

Scoletoma acicularum 0 3 0 1 1 0 0 0 0 0 0 0 2 0 0 0 1 1 0 0 0 0 0 0 0 0 0 1

Parapionosyllis longicirrata 0 0 0 0 1 0 0 0 0 0 0 0 6 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

Aricidea catherinae 0 0 21 0 0 0 0 2 0 0 0 0 71 0 0 0 0 0 49 3 8 0 0 0 0 0 0 0

Brania wellfleetensis 0 0 13 3 0 0 0 0 0 0 0 0 24 24 3 11 2 1 25 7 6 0 0 0 0 0 0 0

Aricidea cerrutii 0 0 0 0 0 0 0 0 0 0 0 1 75 6 0 1 4 0 0 1 13 0 0 0 0 0 0 0

Streptosyllis arenae 2 0 0 0 0 0 0 1 0 0 0 0 5 5 0 0 0 0 0 8 16 0 0 0 0 0 0 0

Lumbrinerides acuta 0 0 1 0 0 0 0 0 0 0 0 0 4 0 0 3 0 0 3 0 13 0 0 0 0 0 0 0

Hesionura elongata 3 0 0 0 0 11 0 0 0 1 0 0 14 0 0 0 0 0 5 49 44 0 0 0 0 0 0 1

Parougia caeca 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 20 33 0 0 0 0 0 0 0

Mooreonuphis pallidula 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 3 10 0 0 0 0 0 0 0

3 

Ampelisca bicarinata 0 0 0 0 0 0 0 0 0 1 0 0 0 0 4 1 0 1 0 0 0 31 3 0 6 0 0 0

Glycera dibranchiata 0 2 0 0 0 13 0 0 0 0 0 0 0 1 3 0 3 1 0 0 0 1 0 0 0 0 1 2

Natica pusilla 0 0 0 0 0 7 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 6 3 0 0 1

Protodorvillea kefersteini 0 0 0 0 1 18 0 0 0 0 0 0 11 3 0 4 0 0 0 1 0 0 0 0 0 0 0 0

Pisione remota 1 0 0 0 0 67 0 0 0 0 0 0 0 0 0 0 0 0 1 0 6 0 0 0 0 0 0 0

Mytilus edulis 2 0 0 0 0 43 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Crenella decussata 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4 

Crassinella lunulata 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 8 2 0 0 0 0 0 0 0 0 0

Pista cristata 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 7 0 0 0 0 0 0 0 0 0 0

Acanthohaustorius shoemakeri 0 0 1 0 0 0 0 0 0 1 1 11 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 0

Oxyurostylis smithi 0 0 0 0 0 0 0 0 0 0 5 5 0 0 0 0 0 0 0 1 2 0 0 0 1 0 0 2

Amakusanthura magnifica 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 5 0 0

Bathyporeia parkeri 0 0 1 0 0 0 0 0 5 0 0 0 0 0 0 9 2 0 0 1 0 0 0 0 0 0 0 1

Spisula solidissima 0 0 1 2 0 0 1 2 2 0 0 1 0 0 2 0 2 0 0 1 0 1 0 0 0 0 0 0

Chiridotea tuftsi 0 0 0 3 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0

Microprotopus raneyi 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 3 0 0 0 0 0 0 2

Pandora inflata 0 0 0 0 0 0 0 0 0 0 0 3 1 0 0 0 0 0 0 0 0 0 2 2 0 0 0 0

Owenia fusiformis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 3 0 1 0 0

Phyllodoce arenae 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 1 2 0 0 0 0

 a Due to the heterogeneity of most taxa distributions, generally low abundances, and relatively limited sampling, only well-defined species groups generated from 

the inverse analyses are numbered. b LPIL = Lowest practical identification level. 
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 Inverse cluster analysis resulted in four groups of taxa (Groups 1 through 4) that reflected 

their co-occurrence in samples collected in Area 1 (Table 6-7). Species Group 1 included the 

amphipods Ampelisca sp. X, B. serrata, and U. irrorata, and the polychaetes A. pygmaea and N. 

picta. Species Group 2 included the most homogeneously distributed taxa in Area 1, including 

the amphipods A. millsi, M. floridana, P. wigleyi, P. obliquua, and R. hudsoni, the bivalve T. 

agilis, the gastropod I. trivittata, the polychaetes Caulleriella sp. J, Spio pettiboneae, and T. 

acutus, the archiannelid Polygordius, and the tanaid T. psammophilus. Group 3 was composed 

entirely of polychaetes, including A. catherinae, A. cerrutii, B. wellfleetensis, H. elongata, L.

acuta, Mooreonuphis pallidula, P. caeca, and S. arenae. Group 4 taxa included the amphipod 

Ampelisca bicarinata, the bivalves C. decussata and M. edulis, the gastropod N. pusilla, and the 

polychaetes G. dibranchiata, P. remota, and Protodorvillea kefersteini.

 Station groups in Area 1 were separated entirely according to survey, with Groups X and 

B composed of May survey stations and Groups A, C, and D consisting of stations sampled 

during September. Associations of species groups with station groups were apparent, primarily 

during the September survey. Species Group 1 taxa were most abundant at Group D stations, 

which mostly had sandy substrata. Species Groups 2 and 3 were associated with Station 

Group C, which tended to have measurable amounts of gravel. Station 5 sediment was 

classified as clayey sand and this station yielded an abundance of the polychaete T. acutus and 

relatively few amphipods. The bivalve Solemya velum was found only in Area 1 at Station 5 

during the September survey. 

6.3.4.4 Area 2 

 Normal cluster analysis resulted in three station groups in Area 2 (Groups A through C) 

(Table 6-8). Group A was composed of a single station during the May survey that was 

depauperate in terms of infaunal abundance and number of taxa. Group A did yield taxa that 

were absent at all other stations in Area 2 (the polychaete Diopatra cuprea and gastropods 

Euspira heros and Turbonilla interrupta). Station Group B was composed of one station from 

each survey, and was distinguished from other station groups primarily by the presence of the 

isopod C. tuftsi and generally low abundances of infaunal taxa. Station Group C consisted of 

four stations from the September survey that yielded high densities of the amphipods A. millsi, 

A. shoemakeri, M. floridana, and P. obliquua, the gastropod I. trivittata, and the polychaetes 

Capitella capitata, Caulleriella sp. J, and N. picta. Certain taxa were yielded by Group C 

stations that were not found in Groups A or B, including the amphipods Metatiron tropakis and 

R. hudsoni, the cumaceans C. varians and O. smithi, and the gastropod R. punctostriatus. 

 Inverse cluster analysis resulted in two groups of co-occurring taxa (Groups 1 and 2) in 

Area 2 (Table 6-8). Group 1 included sparsely distributed taxa such as the amphipods 

Metatiron tropakis and U. irrorata, the bivalve S. solidissima, the cumaceans C. varians and O. 

smithi, and the gastropod Acteocina bidentata. Group 2 was composed of the most 

homogeneously distributed taxa in Area 2 and included the amphipods A. millsi, A. shoemakeri, 

M. floridana, P. obliquua, and P. wigleyi, the archiannelid Polygordius, the bivalve T. agilis, the 

polychaetes C. capitata, Caulleriella sp. J, and N. picta, and the tanaid T. psammophilus. 

 Species Groups 1 and 2 both were associated with Station Group C (September survey). 

Stations in Group C had sand substrata and yielded many more amphipods than did those Area 

2 stations that had measurable gravel, although both Area 2 stations with gravelly sand were 

sampled during the May survey; therefore, it is unknown the degree to which seasonal 

differences accounted for variable infaunal assemblage structure between stations. 
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Table 6-8. Two-way table from normal (Station Groups A–C) and 

inverse (Species Groups 1 and 2

a

) cluster analysis of

infaunal samples collected during the May 1998 

Survey 1 (S1) and September 1998 Survey 2 (S2) in 

Sand Resource Area 2 (A2) offshore North Carolina. 

Data are presented as total counts for individual taxa. 

A B C 

Taxon 

S1-A2-2 S1-A2-4 S2-A2-3 S2-A2-1 S2-A2-2 S2-A2-4 S2-A2-5 

Spisula solidissima 0 1 1 0 3 1 1

Metatiron tropakis 0 0 0 0 3 1 1

Cyclaspis varians 0 0 0 1 4 1 0

Oxyurostylis smithi 0 0 0 1 3 1 0

Rictaxis punctostriatus 0 0 0 2 1 2 0

Edotia triloba 0 1 0 1 1 1 0

Acteocina bidentata 0 0 0 0 2 1 0

Unciola irrorata 0 0 0 0 1 1 0

1

Americhelidium americanum 0 0 0 0 2 0 0

Protodorvillea kefersteini 0 0 0 0 2 0 0

Travisia parva 0 0 0 0 1 0 0

Lumbrinerides acuta 0 0 0 0 1 0 0

Ampelisca sp. X 0 0 0 3 0 0 1

Natica pusilla 0 0 0 3 0 0 0

Spiophanes bombyx 0 0 0 1 0 0 1

Glycera dibranchiata 0 0 0 1 0 0 1

Magelona papillicornis 0 0 0 1 0 0 0

Acteocina candei 0 0 0 1 0 0 0

Epitonium multistriatum 0 0 0 1 0 0 0

Listriella barnardi 0 0 0 1 0 0 0

Pseudoleptocuma minor 0 0 1 0 0 0 0

Argissa hamatipes 0 0 1 0 0 0 0

Encope aberrans 0 0 1 0 0 0 0

Rhepoxynius hudsoni 0 0 0 30 0 0 14

Byblis serrata 0 0 0 0 0 0 20

Brania wellfleetensis 0 0 1 0 2 0 3

Owenia fusiformis 0 0 1 0 0 0 4

Pista quadrilobata 0 0 0 0 0 0 3

Scoletoma acicularum 0 0 0 0 0 0 1

Ampharete acutifrons 0 0 0 0 0 0 1

Loimia medusa 0 0 0 0 0 0 1

Phyllodoce arenae 0 0 0 0 0 0 1

Apoprionospio pygmaea 0 0 0 0 0 0 1

Pandora inflata 0 0 0 0 0 0 1

Pagurus longicarpus 0 0 0 0 0 1 0

Moira atropos 0 0 0 0 0 1 0

Ptilanthura tenuis 0 0 0 0 0 1 0

Acanthohaustorius millsi 0 0 0 112 0 3 0

Acanthohaustorius shoemakeri 0 0 0 22 2 4 0

Metharpinia floridana 5 0 2 0 40 28 0

Protohaustorius wigleyi 3 6 29 11 2 14 0

Tanaissus psammophilus 8 2 26 6 8 9 0

Pseudunciola obliquua 0 4 5 158 7 38 20

Polygordius (LPIL

b

) 0 0 7 2 15 1 53

Ilyanassa trivittata 0 0 0 0 2 17 4

Tellina agilis 0 0 4 1 4 4 6

Capitella capitata 0 0 0 10 3 4 13

Caulleriella sp. J 0 1 0 1 2 5 10

Nephtys picta 0 0 1 6 2 1 5

2

Chiridotea tuftsi 0 1 12 0 0 0 0

Bathyporeia parkeri 0 3 4 1 5 0 0

Ancinus depressus 0 0 7 1 5 0 0

Drilonereis longa 0 1 0 0 0 0 0

Cyathura polita 0 1 0 0 0 0 0

Diopatra cuprea 1 0 0 0 0 0 0

Euspira heros 1 0 0 0 0 0 0

Turbonilla interrupta 1 0 0 0 0 0 0

a Due to the heterogeneity of most taxa distributions, generally low 

abundances, and relatively limited sampling, only well-defined species 

groups generated from the inverse analyses are numbered. b LPIL = Lowest practical identification level. 
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6.3.4.5 Area 3 

 Normal cluster analysis resulted in three station groups in Area 3 (Groups A through C). 

Station Group A included one station from each survey that each yielded less than half of the 

taxa included in the inverse analysis for Area 3 (Table 6-9). Group A stations did yield several 

polychaete taxa that were absent in Station Groups B and C, including B. wellfleetensis, E. 

rolani, P. longicirrata, Polycirrus sp. G, S. acicularum, and S. setosa. Group B included stations 

from both the May and September surveys, while Group C was composed only of stations 

sampled during the September survey. Groups B and C both yielded relatively high numbers of 

various amphipod taxa that were absent from Group A stations, including A. millsi, M. floridana, 

P. wigleyi, and P. obliquua. Group C was distinguished from Group B by yielding high densities 

of the amphipods A. bicarinata B. serrata, and U. irrorata, and the polychaetes A. pygmaea, N. 

picta, Paraprionospio pinnata, S. bombyx, and T. acutus. 

 Inverse cluster analysis resulted in four groups of co-occurring taxa (Groups 1 through 4) 

in Area 3 (Table 6-9). Species Groups 1 and 2 included homogeneously distributed taxa, while 

Groups 3 and 4 included taxa that did not occur at most Area 3 stations. Group 1 was 

composed entirely of crustaceans, including the amphipods A. millsi, M. floridana, P. obliquua, 

and P. wigleyi and the tanaid T. psammophilus. Group 2 included the amphipods A. bicarinata

B. serrata, and U. irrorata and the polychaetes A. pygmaea, N. picta, Paraprionospio pinnata, S. 

bombyx, and T. acutus. Species Group 3 taxa were found primarily at a single station during 

the September survey, including the gastropod Crepidula fornicata and the polychaetes 

Bhawania heteroseta, Lysilla alba, P. remota, Pista quadrilobata, Schistomeringos pectinata, 

and Scoletoma ernesti. Group 4 included the polychaetes B. wellfleetensis, E. rolani, P.

longicirrata, Polycirrus sp. G, and S. setosa. 

 Associations between species groups and particular station groups were apparent in Area 

3. Species Group 2 was associated with Station Group C, which consisted of September 

stations that had sand bottoms. Species Groups 3 and 4 were associated with Station Group 1, 

which included two stations that had measurable gravel, one of these with gravelly sand and the 

other with sandy gravel. Species Group 1 included amphipod crustaceans that were distributed 

across both surveys and across most Area 3 stations. Most Area 3 stations had sand substrata. 

6.3.4.6 Area 4 

 Normal cluster analysis resulted in three station groups (Groups A through C) in Area 4 

(Table 6-10). Groups A (1 station) and B (2 stations) included stations from the May survey, 

while Group C (10 stations) included all stations sampled during the September survey. Station 

Groups A and B both were characterized by low abundance and taxa richness, although Group 

A stations did yield taxa not represented in Group B, including the crustaceans A. americanum

(amphipod) and C. tuftsi (isopod), the bivalve S. solidissima, and the polychaete L. acuta. 

Group B yielded taxa not collected at Group A stations, including the amphipods A. millsi, P.

wigleyi, and P. obliquua and the tanaid T. psammophilus. Station Group C was distinguished 

from the other station groups by yielding many more taxa and individuals, including several 

species not collected from Groups A or B (i.e., the May survey). Taxa that were collected only 

at Group C stations included the amphipods A. bicarinata, B. serrata, R. hudsoni, and U. 

irrorata, the archiannelid Polygordius, the bivalve Tellina agilis, the cumaceans C. varians and 

O. smithi, and the polychaetes N. picta, Orbinia riseri, P. pinnata, and S. bombyx. 

 Inverse cluster analysis resulted in three groups of co-occurring taxa (Groups 1 through 3) 

(Table 6-10). Group 1 taxa were collected during both surveys, Group 2 taxa were collected 
187

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Table 6-9. Two-way table from normal (Station Groups A–C) and inverse (Species Groups 1-4a) cluster analysis of

infaunal samples collected during the May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand 

Resource Area 3 (A3) offshore North Carolina. Data are presented as total counts for individual taxa.

A B C 

Taxon 

S1-A3-2 S2-A3-6 S1-A3-10 S1-A3-13 S1-A3-3 S1-A3-4 S2-A3-3 S2-A3-4 S2-A3-7 S2-A3-2 S2-A3-1 S2-A3-5 S2-A3-10 S2-A3-12 S2-A3-8 S2-A3-11 S2-A3-13 S2-A3-9 

Protohaustorius wigleyi 2 4 251 15 7 14 14 75 70 7 2 9 134 130 195 42 87 191

Pseudunciola obliquua 0 0 20 6 34 2 0 15 68 0 0 5 0 3 19 1 3 5 

Acanthohaustorius millsi 0 0 18 3 8 10 10 16 27 0 0 0 40 7 8 1 3 9 

Metharpinia floridana 0 0 4 3 0 0 0 4 16 0 0 2 0 0 0 11 12 6 

Tanaissus psammophilus 0 0 7 5 3 5 6 4 3 0 0 1 0 0 1 0 0 0 

1

Apoprionospio pygmaea 0 2 0 0 0 0 0 0 8 5 42 93 25 33 52 28 62 15 

Nephtys picta 2 0 1 7 1 1 3 1 5 7 33 36 43 42 18 34 57 22 

Ampelisca bicarinata 0 2 0 0 0 0 0 0 13 0 1 5 14 69 16 68 6 6 

Polygordius (LPILb) 54 10 0 0 0 0 4 3 1 10 5 15 13 8 2 22 9 3 

Byblis serrata 0 0 2 1 0 0 1 1 5 17 4 8 11 5 7 76 16 10 

Tharyx acutus 0 3 0 0 0 0 0 1 1 1 9 23 11 3 6 2 13 21 

Caulleriella sp. J 3 3 3 3 0 0 1 1 1 5 6 5 0 9 0 1 5 0 

Unciola irrorata 0 7 0 0 0 0 0 0 0 1 0 3 0 6 1 6 6 2 

Spiophanes bombyx 0 0 0 2 0 0 1 0 1 3 0 5 8 4 1 2 8 3 

Paraprionospio pinnata 0 0 0 0 0 0 0 0 1 0 0 9 2 2 0 5 4 2 

2

Unciola serrata 0 0 0 0 0 0 0 0 0 0 0 0 23 0 0 0 0 0 

Rhepoxynius hudsoni 0 3 0 0 0 0 0 0 0 2 0 0 4 4 5 0 0 0 

Owenia fusiformis 0 0 0 0 0 0 0 3 0 0 0 0 5 0 4 0 0 2 

Capitella capitata 0 0 0 0 0 0 0 0 0 1 0 0 0 1 3 3 0 0 

Orbinia riseri 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 6 12 

Aricidea wassi 0 0 7 0 0 0 0 0 1 0 0 0 0 0 0 1 4 2 

Caecum pulchellum 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 7 1 

Oxyurostylis smithi 0 0 0 0 0 0 0 4 5 0 1 0 0 1 1 2 2 0 

Cyclaspis varians 0 0 0 0 0 0 0 1 2 0 0 0 0 0 4 2 2 0 

Americhelidium americanum 0 0 0 0 0 0 0 0 2 0 1 0 0 0 1 0 2 1 

Natica pusilla 0 0 0 0 0 0 0 0 1 0 1 3 0 2 1 3 2 0 

Rictaxis punctostriatus 0 0 0 0 0 0 0 0 0 0 2 0 0 1 1 1 1 0 

Crepidula fornicata 0 23 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 

Schistomeringos pectinata 0 34 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Scoletoma ernesti 0 23 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Lysilla alba 0 15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Pista quadrilobata 0 14 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Bhawania heteroseta 0 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Pisione remota 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

3

Bathyporeia parkeri 0 0 3 0 1 2 0 7 0 0 0 0 0 0 0 0 0 0 

Nephtys bucera 0 0 4 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 

Encope aberrans 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 

Spisula solidissima 0 0 1 1 0 4 0 0 0 0 0 0 0 0 0 1 0 0 

Cyathura polita 0 0 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Acanthohaustorius shoemakeri 0 0 0 0 0 0 0 1 10 0 0 0 0 0 0 0 0 0 

Ancinus depressus 0 0 0 0 0 0 0 6 0 0 0 6 0 0 0 0 0 0 

Chiridotea tuftsi 0 0 0 0 0 0 3 2 0 0 0 0 0 0 0 0 0 0 

Turbonilla interrupta 0 0 0 0 0 0 0 0 0 1 0 0 1 3 0 0 1 3 

Ptilanthura tenuis 0 0 0 0 0 0 0 1 0 2 1 1 1 2 0 0 1 0 

Tellina agilis 0 0 0 0 0 0 3 0 1 0 0 6 0 2 0 0 0 0 

Acanthohaustorius intermedius 0 0 0 0 0 0 1 0 4 1 0 0 0 2 0 0 0 0 

Pandora inflata 0 0 0 0 0 0 1 0 0 1 0 0 1 2 0 0 0 0 

Reticulocythereis sp. A 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 8 0 6 

Acteocina bidentata 0 0 0 0 0 0 0 0 0 0 6 6 0 1 0 0 1 2 

Acteocina candei 0 0 0 0 0 0 0 0 0 0 0 3 3 1 0 0 0 2 

Ampelisca sp. X 0 0 0 0 0 0 0 0 1 7 8 31 0 0 1 0 0 0 

Onuphis eremita 0 0 0 0 0 0 1 0 0 1 4 1 0 0 0 0 0 0 

Goniada littorea 0 0 0 0 0 0 0 0 0 0 3 2 0 0 0 0 0 0 

Lucifer faxoni 0 0 0 0 0 0 0 1 1 0 2 1 0 0 0 0 0 0 

Brania wellfleetensis 4 133 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Spio setosa 74 103 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Polycirrus sp. G 28 278 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Parapionosyllis longicirrata 22 89 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Exogone rolani 30 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

4

Mediomastus (LPILb) 2 8 0 0 0 0 0 0 0 0 1 5 0 0 0 0 0 0 

Ensis directus 2 0 0 0 0 0 0 0 0 0 0 3 1 0 0 0 0 0 

Scoletoma acicularum 9 2 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 

Ilyanassa trivittata 6 1 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 

Glycera dibranchiata 1 1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1 0 a Due to the heterogeneity of most taxa distributions, generally low abundances, and relatively limited sampling, only well-defined species groups 

generated from the inverse analyses are numbered. b LPIL = Lowest practical identification level. 
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Table 6-10. Two-way table from normal (Station Groups A–C) and inverse (Species 

Groups 1-3a) cluster analysis of infaunal samples collected during the May 

1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in Sand Resource 

Area 4 (A4) offshore North Carolina. Data are presented as total counts fo

r

individual taxa. 

A B C 

Taxon 

S1-A4-5 S1-A4-4 S1-A4-9 S2-A4-5 S2-A4-8 

S2-A4-10 

S2-A4-2 S2-A4-3 S2-A4-1 S2-A4-4 S2-A4-7 S2-A4-6 S2-A4-9 

Protohaustorius wigleyi 0 22 0 2 1 28 70 40 105 55 11 45 61

Pseudunciola obliquua 0 7 0 0 0 0 21 10 67 29 3 48 28

Acanthohaustorius millsi 0 13 5 0 0 0 8 22 5 45 11 29 24

Metharpinia floridana 2 2 1 0 16 0 0 0 56 15 9 27 0 

Byblis serrata 0 0 0 2 66 0 0 0 0 1 63 2 3 

Tanaissus psammophilus 0 11 6 3 16 37 5 7 1 1 4 10 20

Polygordius (LPIL) 0 0 0 47 81 42 10 8 9 0 9 13 9 

Tellina agilis 0 0 0 14 12 11 2 3 11 2 3 3 22

Caulleriella sp. J 0 2 1 1 17 10 0 0 6 1 7 0 7 

Ampelisca bicarinata 0 0 0 7 10 2 4 5 2 19 0 7 10

Nephtys picta 1 0 0 2 24 7 0 9 2 8 5 10 5 

Unciola irrorata 0 0 0 1 9 2 0 1 1 9 9 8 3 

1 

Rhepoxynius hudsoni 0 0 0 15 0 37 7 32 0 0 0 0 28

Cyclaspis varians 0 0 0 0 2 4 6 4 8 2 3 3 1 

Spiophanes bombyx 0 0 0 0 1 2 4 5 6 3 2 1 7 

Oxyurostylis smithi 0 0 0 0 0 7 5 5 5 1 0 0 2 

Orbinia riseri 0 0 0 3 11 8 0 0 2 0 1 4 2 

Bathyporeia parkeri 0 2 0 2 2 11 2 1 2 0 1 2 1 

Spio pettiboneae 0 0 0 1 2 4 1 0 0 0 0 2 0 

Paraeupolymnia sp. A 0 0 0 13 1 0 0 0 0 0 0 2 0 

Paraprionospio pinnata 0 0 0 1 1 0 0 2 0 3 0 1 0 

2 

Amakusanthura magnifica 1 1 5 0 0 0 0 0 0 0 0 0 0 

Pseudoleptocuma minor 2 2 1 0 0 0 0 0 0 0 0 0 0 

Lumbrinerides acuta 4 0 0 0 0 0 0 0 0 0 0 0 0 

Chiridotea tuftsi 3 0 0 0 0 0 0 0 0 0 0 0 0 

3 

Spisula solidissima 1 0 0 0 0 0 0 0 4 0 1 0 0 

Americhelidium americanum 1 0 0 0 0 1 0 0 1 1 0 1 0 

Edotia triloba 0 0 0 0 0 0 0 0 3 0 0 1 0 

Acteocina canaliculata 0 0 0 0 0 0 0 0 2 1 0 0 0 

Paraonis fulgens 0 0 0 0 0 4 0 1 0 0 1 0 1 

Onuphis eremita 0 0 0 2 0 1 0 1 0 0 1 1 1 

Ancinus depressus 0 0 0 0 0 1 0 1 1 0 0 0 0 

Phyllodoce arenae 0 0 0 0 2 0 0 0 1 0 0 1 1 

Brania wellfleetensis 0 0 0 0 5 0 0 0 1 0 0 0 0 

Capitella capitata 0 0 0 0 2 1 0 0 1 0 0 0 0 

Aricidea wassi 0 0 1 0 1 0 0 0 1 0 1 0 1 

Asterias forbesi 0 0 0 0 1 0 0 0 1 0 1 0 0 

Ptilanthura tenuis 0 0 0 0 2 1 0 0 0 0 1 0 0 

Parougia caeca 0 0 0 1 2 0 0 0 0 0 0 0 0 

Acteocina candei 0 0 0 1 0 0 2 3 0 0 0 0 0 

Spiochaetopterus oculatus 0 0 0 0 0 0 1 2 0 0 0 0 0 

Acanthohaustorius intermedius 0 0 0 0 0 0 16 0 0 2 0 0 0 

Owenia fusiformis 0 0 0 0 0 0 4 1 0 1 3 0 0 

Apoprionospio pygmaea 0 0 0 0 0 1 2 0 0 18 1 2 2 

Natica pusilla 0 0 0 0 0 0 0 0 0 2 2 2 1 

Rictaxis punctostriatus 0 0 0 0 1 0 0 0 0 2 0 0 2 

Caecum pulchellum 0 0 0 0 1 0 0 0 1 2 0 0 0 

Turbonilla interrupta 0 0 0 0 0 0 0 0 0 4 1 0 0 

Tharyx acutus 0 0 0 0 0 0 0 0 0 3 0 0 0 a Due to the heterogeneity of most taxa distributions, generally low abundances, and 

relatively limited sampling, only well-defined species groups generated from the inverse 

analyses are numbered. b LPIL = Lowest practical identification level. 
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primarily from the September survey, and Group 3 taxa were collected only during the May 

survey. Species Group 1 was composed of the most abundant taxa in Area 4, including the 

amphipods A. bicarinata, A. millsi, B. serrata, M. floridana, P. wigleyi, P. obliquua, and U. 

irrorata, the archiannelid Polygordius, the bivalve T. agilis, and the polychaetes Caulleriella sp. J 

and N. picta. Group 2 taxa included amphipods B. parkeri and R. hudsoni, the cumaceans C. 

varians and O. smithi, and the polychaetes O. riseri, P. pinnata, and S. bombyx. Group 3 taxa 

were the bivalve S. solidissima, the cumacean Pseudoleptocuma minor, the isopods 

Amakusanthura magnifica and C. tuftsi, and the polychaete L. acuta. 

 Species Group 1 taxa generally were distributed across station groups and, therefore, 

across surveys. Species Group 2 was associated primarily with Station Group C (September 

survey) and Species Group 3 was associated with Station Groups A and B (May survey). No 

relationship between infaunal assemblage type and sedimentary regime was apparent in Area 

4; all stations had either sand or slightly gravelly sand. 

6.3.5 Epifauna and Demersal Fishes 

 Trawls taken in the four sand resource areas during the May 1998 Survey 1 yielded very 

few organisms (Table 6-11). With the exception of several skate (Raja sp.) egg cases, only one 

fish specimen was collected, a spotted hake (Urophycis floridana). Four invertebrate taxa were 

collected, with the sea star Asterias forbesi and rock crab (Cancer irroratus) the most abundant. 

Area 3 produced the most specimens, but 32 individuals was considered sparse. 

Table 6-11. Epifauna and demersal fishes collected by mongoose trawl during the 

May 1998 survey of the four sand resource areas offshore North Carolina.

Area Taxa 1 2(out) 3 4 Total 

INVERTEBRATES 

Asterias forbesi 3 15 3 21 

Cancer irroratus 4 14 1 19 

Pagurus sp. 1 1 

Ovalipes ocellatus 1 1 

FISHES 

Raja egg case 10 10 

Urophycis floridana 1 1 

INVERTEBRATE TOTALS 

Total Individuals 7 31 4 42 

Total Taxa 2 4 2 4 

FISH TOTALS 

Total Individuals 10 1 11 

Total Taxa 1 1 2 

FISH AND INVERTEBRATE TOTALS 

Total Individuals 17 32 4 53 

Total Taxa 3 5 2 6 

 
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 During the September 1998 Survey 2, 316 epifaunal invertebrates represented by 13 taxa 

and 412 demersal fishes represented by 11 taxa were collected in the four sand resource areas 

(Table 6-12). The most abundant invertebrate taxa were the sea stars Asterias forbesi and 

Luidia clathrata. The most abundant fish taxa included Stenotomus chrysops, Raja sp. (egg 

cases), and Prionotus scitulus. 

 The highest number of invertebrate taxa (10) was collected in Area 3 and the lowest 

number of invertebrate taxa (4) was collected in Area 2 during the September survey. The 

number of invertebrate taxa per haul averaged 6.6. Area 1 yielded the highest number of fish 

taxa (7), whereas Area 2 yielded the lowest number of fish taxa (3). The average number of fish 

taxa collected per haul was 5.0. 

 The highest number (269) of individuals (fishes and invertebrates combined) was 

recorded from Area 1 and the lowest number (47) in Area 2 during the September survey. The 

number of fishes in the trawl tows for the September 1998 survey ranged from 221 in Area 1 to 

28 in Area 3 and averaged 82.4. Invertebrate numbers ranged from 100 in Areas 2(out) and 3 

to 16 in Area 2(in) and averaged 63.2 individuals per tow. 

6.4 DISCUSSION 

 Benthic assemblages surveyed from sand resource areas offshore North Carolina 

consisted of members of the major invertebrate and vertebrate groups that commonly occur in 

the study region. Numerically dominant infaunal groups included numerous crustaceans, 

echinoderms, mollusks, and polychaetes, while epifaunal taxa consisted primarily of decapods, 

sea stars, and squid. Demersal fishes collected in trawls within the sand resource areas also 

were common in previous surveys, including clearnose skate (Raja eglanteria), flounder 

(Paralichthys sp.), scup (Stenotomus chrysops), and searobin (Prionotus scitulus). These 

species were numerical dominants during the 1998 sand resource area surveys and are among 

the common demersal taxa that occur in the region (Grosslein, 1976; Sandifer et al., 1980; 

MMS, 1989). 

 Canonical discriminant analysis combining May and September infaunal data indicated 

that the composition of benthic assemblages inhabiting North Carolina resource area stations 

was affected primarily by survey, and secondarily by sediment type. Normal cluster analysis 

resulted in Station Groups C (13 stations) and D (29 stations) that were composed only of 

samples collected during the September survey, indicating seasonal differences in assemblage 

composition. Temporal variability in infaunal assemblage composition also was evidenced by 

both qualitative and quantitative community measures. Less than half (34% of total) of the 

infaunal taxa sampled over the entire project were collected during both the May and 

September surveys. Most (59%) of the remainder of censused taxa were collected only during 

the September cruise, resulting in higher mean values of species richness compared to the May 

survey. Also, infaunal abundance was greater during the September survey 

(321 individuals/grab) than during May (106 individuals/grab). Greater infaunal taxa richness 

and individual abundance during September could have been related to either seasonal 

parameters or other environmental factors that varied independent of season during the survey 

period. Increased abundance during warmer months has been observed in some amhipod 

populations inhabiting OCS areas of the Middle Atlantic Bight (Schaffner and Boesch, 1982). It 

also is possible that survey differences were an artifact of the sampling design used for the 

North Carolina sand resource areas investigation. During the expanded September sampling 

effort, more than twice the number of grab samples (50) were collected as were collected during 

the May survey (20). 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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Table 6-12. Epifauna and demersal fishes collected by mongoose trawl during the 

September 1998 survey of the four sand resource areas offshore North 

Carolina. 

Area Taxa 

1 2(in) 2(out) 3 4 

Grand 

Total 

INVERTEBRATES 

Asterias forbesi 4 11 41 73 4 133 

Luidia clathrata 35 26 15 44 120 

Loligo pealei 5 3 21 3 32 

Pagurus longicarpus 2 1 6 2 1 12 

Libinia dubia 5 5 

Ovalipes ocellatus 1 1 2 4 

Cancer irroratus 1 1 1 3 

Mellita quinquiesperforata 1 1 2 

Astropecten articulatus 1 1 

Callinectes sapidus 1 1 

Hyas sp. 1 1 

Persephona punctata 1 1 

Portunus gibbesii 1 1 

FISHES 

Stenotomus chrysops 207 18 21 27 10 283 

Raja egg cases 3 12 48 27 90 

Prionotus scitulus 2 1 14 17 

Paralichthys sp. 3 3 6 

Raja eglanteria 2 1 2 1 6 

Synodus foetens 3 3 

Dasyatis americana 1 1 2 

Peprilus triacanthus 2 2 

Decapterus punctatus 1 1 

Hippocampus erectus 1 1 

Urophycis floridana 1 1 

INVERTEBRATE TOTALS 

Total Individuals 48 16 100 100 52 316 

Total Taxa 6 4 6 10 6 13 

FISH TOTALS 

Total Individuals 221 31 74 58 28 412 

Total Taxa 7 3 6 5 4 11 

INVERTEBRATE AND FISH TOTALS 

Grand Total Individuals 269 47 174 158 80 728 

Grand Total Taxa 13 7 12 15 10 24 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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 Results of the North Carolina sand resource area surveys agree with previous 

investigations that found particular infaunal taxa associated with specific sedimentary habitats 

(Sanders, 1958; Young and Rhoads, 1971; Pearce et al., 1981; Barry A. Vittor & Associates, 

Inc., 1985; Weston, 1988; Chang et al., 1992). An infauna-habitat relationship was apparent in 

the results of the resource area surveys, despite relatively limited sampling in the study area. 

Canonical correlation analysis indicated that the composition of benthic assemblages inhabiting 

resource area stations mostly was affected by relative percentages of gravel and sand. 

 Weston (1988) found that season was less of an influencing factor than sedimentary 

regime on infaunal assemblage composition in waters offshore North Carolina. Those findings 

apparently contrast with the sand resource area surveys that found the importance of sediments 

as secondary to survey, which could imply seasonality. Day et al. (1971) determined that 

infaunal distribution varies along a depth gradient from the beach zone to the edge of the 

continental shelf off North Carolina. The turbulent zone includes the inner shelf between 3- and 

20-m depths, while a different outer shelf assemblage occurs at between 40 and 120 m. In the 

Weston (1988) investigation of inner shelf assemblages off Cape Hatteras, infauna were 

collected quarterly at bottom depths ranging from 23 to 54 m, substantially deeper than those at 

the sand resource area stations, which ranged from 14 to 24 m. Whether differences in depth of 

sampling between the sand resource area surveys and the Weston (1988) investigation can 

account for the apparent difference in the results of the two investigations ultimately is unknown. 

It simply may be a matter of natural variability of infaunal population recruitment patterns, abiotic 

parameters, or a combination of both. 

 Despite a difference in infaunal assemblage composition between surveys, temporal 

variability may not have been due to ordinary seasonal changes in the distribution and 

abundance of infaunal populations, if, in fact, such patterns exist. Using Folk’s sediment 

description, which was used to categorize sediments collected with infaunal grabs, the 

percentage of stations with pure sand (i.e., not slightly gravelly sand or gravelly sand) increased 

from 20% of the May total (4 of 20 stations) to 66% during September (33 of 50). 

Complementary SPI data from sand resource area stations indicated that a layer of well sorted, 

fine sand apparently was deposited over much of the area prior to the September survey, 

possibly a result of sediment transport and reworking due to Hurricane Bonnie, which passed 

through the study area during August 1998. Between-survey sedimentary differences 

apparently were not sufficient to correlate with the first canonical variate in the discriminant 

analysis. However, change in surficial sediment composition between May and September 

probably accounted for some of the between-survey differences in infaunal assemblage 

composition. 

 Infaunal assemblage distributions therefore likely were a reflection of sediment type 

distributions during the resource area surveys. Of the four sand resource areas, Area 1 was the 

most heterogeneous based on normal cluster analysis of the infaunal data (Figure 6-39). 

Surficial sediments were mixtures of sand and gravel (Folk’s description) at about half of the 

stations in the northernmost resource area (Area 1), as compared to more spatially uniform 

sand in southern resource areas (Areas 3 and 4). Accordingly, Areas 3 and 4 generally were 

more spatially homogeneous in terms of infaunal assemblage types delineated by normal 

analysis. The southernmost resource areas included a few stations with relatively high gravel 

content but most other stations in these resource areas were characterized by sand substrata 

(Figure 6-40). Adjacent station assemblages were similar to those at nearby stations within 

adjacent resource areas during both 1998 surveys. 

 
193

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MMS Study 2000-056 Figure 6-40. Grain size composition of infaunal samples collected during the May 1998 Survey 1 (S1) and September 1998 Survey 2 (S2) in the four sand resource areas (A1, A2, A3, A4) and two adjacent stations (R1 and R2) offshore North Carolina. 

Percent

0

908070605040302010

100

XA B C D

Group

S1-A1-8

S1-A1-6

S2-A1-5

S1-A1-10

S1-A1-20

S1-A1-7

S1-A4-5

S1-R1

S2-A1-4

S1-A3-2

S2-A3-6

S1-A2-2

S1-A4-9

S1-A2-4

S1-A3-3

S1-A3-4

S1-A3-13

S1-A3-10

S1-A4-4

S1-A1-1

S1-A1-16

S1-A1-9

S1-R2

S2-A3-3

S2-A2-2

S2-A2-4

S2-A2-3

S2-A3-4

S2-A1-3

S2-A1-7

S2-A1-8

S2-A1-16

S2-A1-9

S2-A4-5

S2-A1-10

S2-A1-17

S2-A2-5

S2-A1-20

S2-A1-13

S2-A1-14

S2-A4-8

S2-A1-1

S2-A1-2

S2-A1-19

S2-A3-2

S2-A3-1

S2-A1-6

S2-A3-5

S2-R1

S2-A2-1

S2-A1-11

S2-A1-12

S2-A1-15

S2-A4-10

S2-A4-2

S2-A4-3

S2-A4-1

S2-A4-7

S2-A4-6

S2-A4-9

S2-A1-18

S2-A3-10

S2-A3-12

S2-A3-8

S2-A3-7

S2-A4-4

S2-A3-9

S2-A3-11

S2-A3-13

S2-R2

GravelSandMud
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 Many infaunal taxa collected during the resource area surveys were distributed across a 

relatively broad sedimentary regime, while others primarily were found at stations with either 

varied amounts of measurable gravel or pure sand. Infaunal assemblages are composed of 

taxa that are adapted to particular sedimentary habitats, with foraging effectiveness a key 

aspect that is closely related to sediment particle size and type (Sanders, 1958; Rhoads, 1974). 

Ubiquitous taxa in sand resource areas included the amphipods Byblis serrata and Metharpinia

floridana, the archiannelid Polygordius, the bivalve Tellina agilis, and the polychaetes 

Caulleriella sp. J, Nephtys picta, Paraprionospio pinnata, and Spiophanes bombyx. 

 Other taxa were associated with narrowly defined sedimentary habitats. Resource area 

stations with surficial sediments containing measurable gravel yielded some taxa that were rare 

at sand bottom stations. These gravel-inhabiting taxa included the gastropod Crepidula

fornicata and the polychaetes Aricidea catherinae, Brania wellfleetensis, Exogone rolani, 

Hesionura elongata, Parapionosyllis longicirrata, Parougia caeca, Pisione remota, and 

Polycirrus sp. G. The numerically dominant archiannelid Polygordius, while collected at most 

resource area stations, was more abundant at stations with sediments containing measurable 

gravel. Gravel provides interstitial microhabitat for these foraging infauna. Infaunal taxa that 

were abundant in sand but not in sediments with measurable gravel included the amphipod 

Protohaustorius wigleyi, the polychaete Apoprionospio pygmaea, and the tanaid Tanaissus 

psammophilus. Most of the infauna-sediment associations found in the sand resource areas 

are consistent with observations from other regional benthic investigations (Gardiner, 1976; 

Pearce et al., 1981; Schaffner and Boesch, 1982; Weston, 1988; Chang et al., 1992). 

 Several benthic investigations have found that the percentage of very fine sediments (i.e., 

clay or silt) can be a key determinant of infaunal population distributions, but overall, sediments 

at resource area stations contained only small amounts of fine sediment during the 1998 

surveys. Infaunal assemblage composition in the resource areas would have been different had 

there been more stations with greater proportions of very fine sediment. One station during the 

September survey (Station 5 in Area 1) had sediment classified as clayey sand; this station 

yielded a relatively great abundance of the polychaete T. acutus, few amphipods, and the 

deposit feeding bivalve Solemya velum. S. velum was not found at any other resource area 

station during either of the 1998 surveys. 

 Results of habitat mapping using SPI data show only some consistency with sediment 

types defined using sediment texture analysis. The primary limitation when comparing sediment 

types defined by either method is an inherent absence of definitive knowledge of actual 

sediment grain size ratios using SPI, especially in areas that have poorly sorted sediments. For 

example, sediments that are described as slightly gravelly sand using Folk’s methodology may 

be defined simply as fine sand or very fine sand using SPI methods. An example of this 

disparity is seen in Area 1 during September, when many stations had surficial sediments 

measured as slightly gravelly sand or gravelly sand, while SPI data from that survey indicated a 

fairly homogeneous area of very fine sand (Figure 6-10). As indicated above, seemingly minor 

amounts of gravel or silt in surficial sediments can affect infaunal assemblage composition to a 

great degree. Taxonomic analysis of infauna collected in Area 1 during September 

corresponded to sediment texture analysis, with the infaunal assemblage types delineated by 

normal analysis distributed between stations with sand (Station Group D) and stations with 

measurable gravel (Station Group C) (Figures 6-39 and 6-40). 

 Other comparisons between habitats based on infaunal composition, and therefore 

sediment texture analysis, and those based on SPI analysis are stronger. A clear example of 

the similarity of results between the two methodologies is evident in Area 3, where SPI data 

indicated an area of variable sediment texture along a northwest to southeast station line in the 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

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southern half of the resource area (Figures 6-28). Sediment texture analysis similarly found 

varied sedimentary habitats at these Area 3 stations. Normal cluster analysis of infaunal 

composition at these stations resulted in varied assemblages in this area, with two assemblage 

types delineated during May and three assemblage types delineated during September (Table 

6-9). 

 A comparison of grain size categories estimated from SPI versus modal, median, and 

mean grain sizes determined from grab samples during both field surveys shows that the SPI 

consistently underestimates grain size (Figure 6-41). Most SPI samples fell in the 4 to 3 phi 

size class, whereas none of median or mean grain sizes from grab samples were above 3 phi. 

Similarly, none of the modal grain sizes determined from grab samples exceeded 3 phi. These 

comparisons include SPI and grab samples collected at the same stations, but not at precisely 

the same location on the seafloor. Thus, some small-scale habitat heterogeneity could lead to 

observed differences, but it is unlikely that variation would lead to such consistent differences 

shown in Figure 6-41. 

 Trawl samples in the sand resource areas indicated depauperate conditions during the 

May survey. Ultimately, sparse demersal epifauna and fishes yielded during May, along with 

relatively limited sampling, preclude any definitive statements about possible causes of temporal 

variability in their abundance and distribution, other than natural variability. Offshore North 

Carolina, there is considerable variation in the abundance and distribution of epifaunal and 

demersal fish taxa, both spatially and seasonally (Grosslein, 1976; Wigley and Theroux, 1981; 

Colvocoresses and Musick, 1984; Ross, 1985; MMS, 1989; Gabriel, 1992), and this dynamic 

may have been manifest in the results of the sand resource area surveys. 

 Some patterns of epifaunal and demersal fish distribution and abundance observed during 

the sand resource area surveys are comparable to historic data. Atlantic rock crab (Cancer

irroratus), a species known to inhabit inner shelf waters year round (MMS, 1989), was one of 

the few taxa collected during both the May and September surveys. Demersal fishes collected 

in trawls within the sand resource areas also were common in previous surveys, including 

clearnose skate, flounder, inshore lizardfish (Synodus foetens), scup, searobin, and southern 

hake (Urophycis floridanus). These fishes are among the common taxa that occur in the region 

(Grosslein, 1976; Sandifer et al., 1980; MMS, 1989; Gabriel, 1992). Overall, fish abundance 

was greater during September than during May. This general temporal abundance pattern 

agrees with the results of previous long-term sampling efforts that found peak fish abundances 

occur offshore North Carolina during the months of September through November. Scup was 

the numerically dominant fish taxon (69% of individuals) during the September survey but was 

not collected during May. This also agrees with historic patterns of distribution; scup tend to 

aggregate along the shelf break during winter, and occur at all depths on the shelf during 

summer months (Grosslein, 1976). Overall, trawl contents were not inconsistent with historic 

regional investigations. Additional information on demersal fish assemblages in and around the 

four sand resource areas may be contained in the unpublished trawl data set collected by North 

Carolina Division of Marine Fisheries aboard the R/V DAN MOORE. These data, collected in 

shelf waters of the state during fall and spring months from 1974 to 1981, were summarized by 

Ross (1985). 

 The results of the benthic surveys of the North Carolina sand resource areas agree well 

with previous descriptions of benthic assemblages residing in shallow shelf waters offshore 

North Carolina. Overall, canonical discriminant analysis indicated that survey most affected the 

composition of infaunal assemblages, although sediment texture may have had the greatest 

influence. Despite inherent spatial and temporal heterogeneity in the distribution and abundance 
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of demersal taxa, results of the 1998 surveys of the sand resource areas generally are 

consistent with results of historical demersal survey results in the region. 

Figure 6-41. Comparison of grain size estimates between sediment profile camera and Smith-McIntyre 

grabs. (a) Sediment grain size classes plotted for each station sampled by sediment profile 

camera during the May 1998 Survey 1 and September 1998 Survey 2 offshore North 

Carolina; (b) modal grain size plotted for each station sampled by Smith-McIntyre grab 

during the May 1998 Survey 1 and September 1998 Survey 2 offshore North Carolina. Sampling Station

Size class (phi) Mode (phi)

-1 0 1 2 3 4 5 -1 0 1 2 3 4 5

-1 0 1 2 3 4 5 -1 0 1 2 3 4 5

(a) (b)

R1

R2

A1-01

A1-02

A1-03

A1-04

A1-05

A1-06

A1-07

A1-08

A1-09

A1-10

A1-11

A1-12

A1-13

A1-14

A1-15

A1-16

A1-17

A1-18

A1-19

A1-20

A2-01

A2-02

A2-03

A2-04

A2-05

A3-01

A3-02

A3-03

A3-04

A3-05

A3-06

A3-07

A3-08

A3-09

A3-10

A3-11

A3-12

A3-13

A4-01

A4-02

A4-03

A4-04

A4-05

A4-06

A4-07

A4-08

A4-09

A4-10
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7.0 POTENTIAL EFFECTS 

One of the primary purposes of this project is to provide site-specific information for 

decisions on requests for non-competitive leases from other local, State, and Federal agencies. 

The information may be used to determine whether or not stipulations need to be applied to a 

lease. The information also may be incorporated into an Environmental Assessment (EA) or 

Environmental Impact Statement (EIS), if so required. 

 Environmental impact analyses of mining operations should be based on 

commodity-specific, technology-specific, and site-specific information, whenever possible 

(Hammer et al., 1993). First, the specific mineral of interest and the technological operations for 

a specific mining operation need to be defined because these two parameters determine the 

impact producing factors that need to be considered. Once the impact producing factors are 

known, this information can be translated into statements concerning the impacts that might 

occur to the full suite of potentially affected environmental resources that may need to be 

addressed, including geology, chemical and physical oceanography, air quality, biology, and 

socioeconomics. Then, decisions can be made regarding the type of mitigation necessary to 

determine the preferred alternative for a specific marine mining operation to acquire project 

approval. 

 This section focuses on providing information on potential impacts related to physical 

processes and biological considerations of sand mining for beach nourishment from four sand 

resource areas offshore North Carolina. Sand for beach replenishment is the commodity of 

interest. Two primary dredging technologies are available for offshore sand mining operations, 

depending on distance from source to project site, the quantity of sand being dredged, and the 

depth to which sand is extracted at a site (Herbich, 1992). They are: 1) cutterhead suction 

dredge, where excavated sand is transported through a direct pipeline to shore, and 2) hopper 

dredge, where sand is pumped to the hopper, transported close to the replenishment site, and 

pumped to the site through a pipeline from the hopper or from a temporary offshore disposal 

area close to the beach fill site. As a general rule, cutterhead suction dredging is most effective 

for projects where the sand resource is close to shore (within 8 km), the dredging volumes are 

large (>8 MCM), and the excavation depth is on the order of 2.5 to 4 m (Taylor, 1999). Hopper 

dredging becomes a more efficient procedure when the sand resource areas are greater than 8 

km from shore, dredging volumes are relatively small (<2 MCM), and the excavation depth at 

the sand resource area is less than 2 m (Taylor, 1999). Ultimately, a combination of these 

factors will be evaluated by dredgers to determine the most cost effective method of sand 

extraction and beach replenishment for a given project. Availability of dredging equipment also 

may be a factor for determining the technique to be used; however, the number of cutterhead 

suction and hopper dredges in operation is about equal in the industry today (Taylor, 1999). As 

such, both technologies will be evaluated for potential biological effects. 

7.1 POTENTIAL SAND BORROW SITES 

 Four potential sand resource areas were identified offshore North Carolina in Federal 

waters by the NCGS and MMS. Each area has specific geologic and geographic characteristics 

that make it more or less viable as a sand resource for specific segments of coast. Areas 1, 2, 

3, and 4 contain borrow sites with the greatest potential for use in the future. 

 All sand resource areas are very similar geologically (medium sand size ridge deposits 

with relief of 2 m or greater and resource volumes of at least 1 MCM). However, sand from the 

eastern borrow site in Area 3 (3 east) has a median grain size of 0.21 mm (fine sand), the 

smallest grain size for any of the potential resource areas. Regardless, all identified potential 
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sand borrow sites are of great interest to the State, primarily due to their proximity to eroding 

beaches critical for storm protection and recreation. Physical processes (waves and currents) 

and biological habitat at borrow sites on sand ridges illustrate relatively small variability. 

However, habitat variability within resource areas varies widely depending on surface area 

boundaries and geographic position. Although these four potential sand resource areas were 

designated as ones with greatest potential, it is possible that sand could be dredged from 

intervening offshore areas. 

 The amount of dredging that occurs at any site is a function of Federal, State, and local 

needs for beach replenishment. It is impossible to predict the exact sand quantities needed in 

the foreseeable future, so a representative value for any given project was estimated based on 

discussions with State personnel and the MMS. Preliminary analysis of short-term impacts 

(storm and normal conditions) at specific sites along the coast landward of sand borrow sites 

indicates that about 1 MCM of sand could be needed for a given beach replenishment event. 

Long-term shoreline change data suggest that a replenishment interval of about 5 to 10 years 

may be required to maintain beaches. This does not consider the potential for multiple storm 

events impacting the coast over a short time interval, nor does it consider longer time intervals 

absent of destructive storm events. Instead, the estimate represents average change over 

decades that is a reasonable measure for coastal management applications. 

 Given the quantity of 1 MCM of sand per beach replenishment event, the surface area 

covered for evaluating potential environmental impacts is a function of average dredging depth. 

Two factors should be considered when establishing dredging practice and depth limits for 

proposed extraction scenarios. First, regional shelf sediment transport dynamics should be 

evaluated to determine net transport directions and rates. It is more effective to dredge the 

leading edge of a migrating shoal, and infilling of dredged areas occurs more rapidly at these 

sites (Byrnes and Groat, 1991; Van Dolah et al., 1998). Second, shoal relief above the ambient 

shelf surface should be a determining factor controlling dredging depth. Geologically, shoals 

form and migrate on top of the ambient shelf surface, indicating a link between fluid dynamics, 

sedimentology, and environmental evolution (Swift, 1976). As such, average shoal relief is a 

reasonable depth threshold for maintaining environmentally-consistent sand extraction 

procedures. 

 A primary question addressed by the modeling efforts relates to sediment transport and 

infilling estimates at potential borrow sites and the impact of dredging operations on these 

estimates. Combined wave-current interaction (waves mobilize the seabed and currents 

transport the sediment) at borrow sites results in a net direction of transport into and out of 

potential sand resource sites. Historical sediment transport dynamics suggest that the net 

direction of sediment movement is from north to south, and the rate at which sand moves along 

the shelf varies. 

7.2 WAVE TRANSFORMATION MODELING 

 Excavation of borrow sites in the nearshore can affect offshore wave heights and the 

direction of wave propagation. The existence of offshore topographic relief can cause waves to 

refract toward the shallow edges of borrow sites. This alteration to the wave field by a borrow 

site may change local sediment transport rates, where some areas may experience a reduction 

in transport, while other areas may show an increase. To determine the potential physical 

impacts associated with dredging borrow sites offshore Dare County,NC, wave transformation 

modeling and sediment transport potential calculations were performed for existing and postdredging bathymetric conditions. Comparison of results for existing and post-dredging 

conditions illustrated the relative impact of borrow site excavation on wave-induced coastal 
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processes. Although the interpretation of wave modeling results was relatively straightforward, 

evaluating the significance of predicted changes for accepting or rejecting a borrow site was 

more complicated (see Section 4.0 for details). 

 For existing conditions model results, bottom features offshore the Outer Banks modified 

wave fields as they propagated shoreward. As an example, wave heights behind the shoal 

feature in the vicinity of Area 1 were about 0.4 m greater than wave heights at the northern and 

southern limits of the shoal. The shoal refracted waves, causing a slight focusing of wave 

energy behind the feature. Because energy was conserved, wave energy focusing behind the 

shoal caused a reduction in energy at the northern and southern edges of the shoal, producing 

reduced wave heights in these areas. In addition to the effects of bottom features far offshore, 

waves were refracted by straight and parallel nearshore bottom contours. For a southeast wave 

approach (Hmo = 1.3 m, Tp = 11.3 sec; see Figure 4-9), waves began to shoal (increase in 

height) about 500 m offshore and increased in height by 0.2 m before breaking begins. Wave 

heights were reduced as energy dissipated in the surf zone (about 60 m wide in this example). 

 Output from post-dredging model runs indicated that wave heights within the borrow site 

in Area 1 were reduced relative to existing conditions, and this effect was more pronounced in 

cases that had greater wave heights. Wave fields landward of proposed borrow sites were 

modified by refraction. As waves propagated across a borrow site (deeper water than the 

surrounding area), wave refraction guided waves away from the center of the excavation area 

and toward the shallower edges. The net effect was to create a shadow zone of reduced wave 

energy (see Figure 4-11) immediately landward of borrow sites and a zone of increased wave 

energy updrift and downdrift of borrow sites. Because spectral wave model results were used, 

and because different frequencies in the spectrum were refracted by varying degrees at the 

borrow site, the regions of increased and reduced wave heights gradually diffused as the wave 

field approached shore. A result of this energy diffusion was that the length of shoreline 

affected by a borrow site can be considerably longer than the borrow area. 

 Another result of the gradual diffusion of wave energy caused by refraction was that 

borrow sites farther offshore have an impact on a longer length of shoreline; however, the actual 

magnitude of impact was smaller because the affected wave field had a greater distance to 

dissipate energy. This result was evident in a comparison of wave energy transformation under 

identical input wave conditions for Borrow Sites 1 and 2. Site 1 was the larger of the two, but it 

is located farther offshore. As such, wave height change from existing to post-dredging 

conditions at the shoreline was less than changes resulting from excavation at Site 2 (see 

Figure 4-12). 

 Because model output for storm wave conditions had a significantly longer period than 

normal conditions, waves were much more responsive to offshore bathymetry gradients. 

Although the direction of wave propagation was not modified as much as was indicated for 

normal wave conditions, wave heights changed significantly (e.g., a maximum height of 2.4 m at 

the southern side of Oregon Inlet) relative to offshore conditions. At offshore shoals directly 

east of the inlet, wave heights increase approximately 0.7 m over the offshore boundary 

condition (Figure 4-14). Several shoal areas along the modeled coastline showed similar 

impacts on wave height, including the area encompassing potential borrow sites. When 

comparing existing and post-dredging wave height changes under storm conditions, the area of 

maximum increased wave heights for post-dredging conditions was located at the northernmost 

corner of Site 1 (see Figure 4-16). The area of maximum wave height decrease also was near 

Site 1, where wave heights were reduced by 0.12 m. Under these conditions, the length of 

affected shoreline, to where borrow site shadows propagate, extends approximately 40 km, 

starting from about 3 km north of Oregon Inlet. 
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7.3 CURRENTS AND CIRCULATION 

 Circulation patterns observed throughout the study area were evaluated within the context 

of potential offshore sand mining operations. Results from this analysis provided estimates of 

sediment transport potential at proposed offshore borrow sites. Analysis of current meter time 

series suggested that along-shelf currents possess higher energy than cross-shelf flows. Mean 

along-shelf flow was directed to the south. Along-shelf currents were dominated by wind-driven 

processes, accounting for as much as 60% of the total current energy. Wind-driven flows 

appeared strongly biased by singular events, either local responses to storm winds or nonlocally generated buoyant flows, that influenced the magnitude of wind-driven current energy. 

Although wind-driven currents were less significant in the cross-shelf direction, the largest 

percentage of cross-shelf energy existed in the wind-driven frequency band. On average, 

cross-shelf currents were directed offshore. Wave groups and long waves inducing infragravity 

motions may further contribute to cross-shore current variability. 

 Previous studies indicated that outflow from the Chesapeake Bay exerts significant 

influence on current patterns in this region (e.g., Beardsley and Boicourt, 1981). Density-driven 

flows likely dominated along-shelf surface currents during the May to September time period 

and enhanced the effects of upwelling-favorable winds. Currents dominated by wind-driven 

processes were stronger between October to December. In addition to wind-driven currents, 

high-frequency (noise, random motions) and low-frequency currents were stronger during winter 

months. This suggested that high- and low-frequency flow processes may be coupled to 

atmospheric forcing. 

 Data synthesized in this analysis, and supported by previous studies, suggested that shelf 

flow was strongest during high-energy wind events, and that near-bottom currents were oriented 

along the shelf (positive along-shelf currents oriented 340°). Wind-driven, near-bottom currents 

were oriented along-shelf nearly 40% of the time for the two periods analyzed. This evidence 

suggested that singular events, with corresponding higher currents, have the greatest potential 

to transport sand. If so, sediment transport patterns may be predominately in the along-shelf 

direction, with a net transport oriented in the direction of mean flow. Based on variability 

analysis, low-frequency (mean) flows were predominantly southwestward. Data also indicated 

that cross-shelf currents were impacted by northeast wind events, driving downwelling during 

summer months and offshore flow of the uniform water column during fall and winter. Strong 

wind events forcing near-bottom offshore flows suggested that cross-shelf sediment transport 

due to currents may be net offshore. 

7.4 SEDIMENT TRANSPORT 

 Current measurements and analyses, and wave transformation modeling, provided 

baseline information on incident processes impacting coastal environments under existing 

conditions and with respect to proposed sand mining activities for beach replenishment. 

Ultimately, the most important information for understanding physical processes impacts from 

offshore sand extraction is changes in sediment transport dynamics resulting from potential 

sand extraction scenarios relative to existing conditions. 

 Three independent sediment transport analyses were completed to evaluate physical 

environmental impacts due to sand mining. First, historical sediment transport trends were 

quantified to document regional, long-term sediment movement throughout the study area using 

historical bathymetric data sets. Erosion and accretion patterns were documented, and 

sediment transport rates in the littoral zone and at offshore borrow sites were evaluated to 

assess potential changes due to offshore sand dredging activities. Second, sediment transport 

patterns at proposed offshore borrow sites were evaluated using wave modeling results and 
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current measurements. Post-dredging wave model results were integrated with regional current 

measurements to estimate sediment transport trends for predicting borrow site infilling rates. 

Third, sediment transport was predicted using wave modeling output to estimate potential 

impacts to the longshore sand transport system (beach erosion and accretion). All three 

methods were compared for documenting consistency of measurements relative to predictions, 

and potential physical environmental impacts were identified. 

7.4.1 Historical Sediment Transport Patterns 

 Regional geomorphic changes between 1862/70 to 1970/96 were analyzed for assessing 

long-term, net coastal sediment transport dynamics. Although these data did not provide 

information on potential impacts of sand dredging from proposed borrow sites, they did provide 

a means of verifying predictive sediment transport models relative to infilling rates at borrow 

sites and longshore sand transport. 

 Shoreline position and nearshore bathymetry change documented four important trends 

relative to study objectives. First, the predominant direction of sediment transport on the 

continental shelf and along southern Bodie Island was north to south. However, littoral transport 

between Kitty Hawk and a point about 10 km north of Oregon Inlet was to the north. The 

greatest amount of shoreline change was associated with beaches adjacent to Oregon Inlet (-2 

to -6 m/yr along southern Bodie Island); since 1849/51, southern Bodie Island has migrated to 

the south at a rate of about 27 m/yr. 

 Second, the most dynamic features within the study area were the beaches and shoals 

associated with Oregon Inlet. Areas of significant erosion and accretion were documented for 

the period 1862/70 to 1970/96, reflecting wave and current dynamics near the entrance and the 

contribution of littoral sand transport from the north to channel, shoal, and spit migration. 

 Third, alternating bands of erosion and accretion on the continental shelf east of the 

Federal-State boundary illustrated relatively slow but steady reworking of the upper shelf 

surface as sand ridges migrated from north to south. The process by which this was occurring 

at all resource areas suggested that borrow sites in these regions would fill with sand 

transported from the adjacent seafloor at rates ranging from 20,000 to 70,000 m3

/yr. For a 2 

MCM sand extraction scenario, infilling times for borrow sites in Areas 1 and 2 would be about 

30 to 35 years. 

 Finally, net longshore transport rates determined from seafloor changes in the littoral zone 

between Kitty Hawk and Oregon Inlet, and nodal point information derived in Section 4.2.2.1, 

indicated increasing transport rates north and south of a point about 10 km north of the inlet. 

Net longshore transport near Nags Head was about 160,000 m3

/yr to the north, increasing to 

about 335,000 m3

/yr near Kitty Hawk. These rates were very consistent with those determined 

from wave modeling and sediment transport predictions. Just north of Oregon Inlet, net 

transport rates were determined to be about 354,000 m3

/yr. 

7.4.2 Sediment Transport Modeling at Potential Borrow Sites 

 In addition to predicted modifications to the wave field, potential sand mining at offshore 

borrow sites resulted in minor changes in sediment transport pathways in and around potential 

dredging sites. Modifications to bathymetry caused by sand mining only influenced local 

hydrodynamic and sediment transport processes in the offshore area. Although wave heights 

changed at the dredged borrow sites, areas adjacent to these sites did not experience dramatic 

changes in wave or sediment transport characteristics. 
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 Initially, it is anticipated that sediment transport at borrow sites will occur rapidly after sand 

dredging is completed. For water depths at the proposed borrow sites, minimal impacts to 

waves and regional sediment transport are expected during infilling. The characteristics of 

sediment that replaces dredged material during infilling will vary based on location, time of 

dredging, and storm characteristics following dredging episodes. Average transport rates 

ranged from a minimum of about 38,000 m3

/yr (Sites 3 east and 4) to a high of about 

123,000 m3

/yr (Site 2), while the infilling time varied between 37 to 98 years (see Table 5-4). 

Site 2 had the greatest infilling rate due to its shallow water depth relative to the other sites and 

its large perimeter. Because Site 2 is in shallow water, wave-induced currents and background 

currents were larger than at deeper surrounding sites, and more sediment was mobile in the 

proximity of the borrow site. Furthermore, sites that have a larger surface area generally will 

trap more sediment in a given time period. The range of infilling times was based of the volume 

of sand numerically dredged from a borrow site, as well as the sediment transport rate. Infilling 

times would have been reduced if storm events were incorporated in the analysis. 

 Total infilling times were computed using the total design excavated volume divided by the 

computed infilling rates, and thus represent the length of time required to fill a site that was 

excavated to the total design depth during a single dredging event. Site 1 has the longest total 

infilling time, resulting from the large volume extracted from this site and the moderate infilling 

volume rate computed for the area. Site 3 west has the shortest infilling time due to its small 

excavation volume, even though it has the smallest infilling rate. The analysis of borrow site 

infilling time assumed a constant rate of transport from each direction and does not include the 

effects of modified bathymetry. For example, as a dredged site begins to fill, sediment transport 

dynamics change. As such, sediment transport rates will fluctuate as a borrow site evolves 

during infilling. This dynamic process is not simulated in the present analysis. However, the 

analysis performed provides a reasonable estimate of infilling times for resource management 

purposes. 

7.4.3 Nearshore Sediment Transport Potential 

 Comparisons of average annual sediment transport potential were performed for existing 

and post-dredging conditions to indicate the relative impact of dredging to longshore sediment 

transport processes. Sediment transport potential is a useful indicator of shoreline impacts 

caused by offshore borrow sites because the computations include the borrow site influence on 

wave height and direction. Net and gross transport potential were computed using existing 

wave conditions and post-dredging conditions for two alternate borrow site configurations: 

1) Sites 1, 2, 3 east, and 4 modeled together, and 2) Sites 1, 2, 3 west, and 4 modeled together. 

A plot of gross and net transport potential indicated that there was a reversal in direction of 

transport along southern Bodie Island (3,970,000 m UTM northing; see Figure 4-17). North of 

this spot, net transport was to the north, while south of this point to Oregon Inlet, net transport 

was strongly to the south. The computed north- and south-directed transport potential showed 

that transport was strongly bi-directional, with a gross transport magnitude of approximately 

600,000 m3

/yr far north of Oregon Inlet and a net transport magnitude of only 250,000 m3/yr. 

Closer to the inlet, littoral drift became more unidirectional and to the south, with gross and net 

transport potential magnitudes peaking at over 600,000 m3

/yr. 

 Difference in longshore transport potential between existing conditions and the two borrow 

site configurations resulted in a maximum negative change (post-dredging minus existing 

condition) in computed net sediment transport potential for the second configuration (Sites 1, 2, 

3 west, and 4), where the peak change was -34,000 m3

/yr, or 45% of the net transport potential 

at this point. The maximum positive change was approximately 14,000 m3

/yr or only 8% of the 

net transport potential computed at this point. 
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 Once the change in sediment transport potential was evaluated between existing and 

post-dredging conditions, the significance of these changes was determined by applying a 

significance criterion based on the natural temporal and spatial variability of sediment transport 

along the modeled coastline. An additional 20 wave model runs were executed to determine 

the significance criterion envelope. Each of the 20 runs represented a single year of the 20-

year WIS hindcast wave dataset. The standard deviation, σ, of sediment transport potential was 

then computed for the entire coastline. The final determination of dredging significance was 

made by comparing actual change in transport potential between existing and post-dredging 

conditions to a significance envelope of one-half the standard deviation (±0.5σ) along the 

shoreline (see Figure 4-24). It was determined that no significant changes to longshore 

sediment transport will result from the modeled borrow site configurations, where borrow Sites 

3 west and 3 east were modeled separately. If Sites 3 east and 3 west were dredged 

simultaneously, the impacts were estimated to exceed the ±0.5σ, and therefore would require 

mitigation along the affected shoreline or a redesign of the borrow site configuration, likely a 

reduction in maximum design depth at one of the sites. 

7.5 BENTHIC ENVIRONMENT 

 The purpose of this section is to address potential effects of offshore sand mining on 

benthic organisms, including analyses of the potential rate and success of recolonization 

following cessation of dredging. This section is divided into three parts. The first two parts 

summarize information from the existing literature on effects and recolonization. The first part 

(Section 7.5.1) describes potential impacts to benthic organisms from the physical disturbance 

of dredging, which causes removal, suspension/dispersion, and deposition of sediments. The 

second part (Section 7.5.2) discusses the potential rate and success of recolonization. Finally, 

the third part (Section 7.5.3) provides predictions of impacts and recolonization relative to the 

four sand resource areas off North Carolina. 

 Ecological effects of marine mining and beach nourishment operations have been 

reviewed by numerous authors (Thompson, 1973; Naqvi and Pullen, 1982; Nelson, 1985; 

Cruickshank et al., 1987; Goldberg, 1989; Grober, 1992; Hammer et al., 1993; National 

Research Council, 1995). Effects vary from detrimental to beneficial, short to long term, and 

direct to indirect (National Research Council, 1995). 

 Most reviews on the effects of beach nourishment operations have focused on potential 

impacts at the beach. Comprehensive assessments of the effects on biological resources at 

open ocean sand borrow sites have been limited (National Research Council, 1995). 

Alterations to biological resources in offshore sand borrow sites are generally of longer duration, 

and the consequences of those changes have not been well-defined (National Research 

Council, 1995). The remainder of this section focuses on potential impacts of dredging 

operations at offshore sand areas. 

7.5.1 Effects of Offshore Dredging on Benthic Fauna 

 The primary impact producing factor relative to dredging offshore sand borrow sites is 

mechanical disturbance of the seabed. This physical disruption includes removal, 

suspension/dispersion, and deposition of dredged material. This section focuses on the 

potential biological effects of these physical processes on benthic fauna. 

7.5.1.1 Sediment Removal 

 Physical removal of sediments from a borrow site removes benthic habitat along with 

infaunal and epifaunal organisms that are incapable of avoiding the dredge, resulting in drastic 
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reductions in the number of individuals, number of species, and biomass. Extraction of habitat 

and biological resources may in turn disrupt the functioning of existing communities. Removal 

of benthic resources is of concern because they are important in the food web for commercially 

and recreationally important fishes and invertebrates, and contribute to the biodiversity of the 

pelagic environment through benthic-pelagic coupling mechanisms. These mechanisms include 

larval transport and diurnal migrations of organisms, which may have substantial impact on food 

availability, feeding strategies, and behavioral patterns of other members of the assemblage 

(Hammer and Zimmerman, 1979; Hammer, 1981). 

 Removal of sand resources can expose underlying sediments and change the sediment 

structure and composition of a borrow site, consequently altering its suitability for burrowing, 

feeding, or larval settlement of some benthic organisms. Many studies show decreases in 

mean grain size, and in some cases, increases in silt and clay in borrow sites following dredging 

(National Research Council, 1995). Changes in sediment composition could potentially prevent 

recovery to an assemblage similar to that which occurred in the borrow site prior to dredging 

and could by implication affect the nature and abundance of food organisms for commercial and 

recreational fishery stocks (Coastline Surveys Limited, 1998; Newell et al., 1998). In some 

cases, dredging borrow sites may create new and different habitat from surrounding substrates, 

which could result in increased habitat complexity and biodiversity of an area. 

 The influence of sediment composition on benthic community composition has been 

recognized since the pioneer studies of Peterson (1913), Thorson (1957), and Sanders (1958). 

However, more recent reviews suggest that precise relationships between benthic assemblages 

and specific sediment characteristics are poorly understood (Gray, 1974; Snelgrove and 

Butman, 1994; Newell et al., 1998). Sediment grain size, chemistry, and organic content may 

influence recolonization of benthic organisms (McNulty et al., 1962; Thorson, 1966; Snelgrove 

and Butman, 1994), although the effects of sediment composition on recolonization patterns of 

various species are not always significant (Zajac and Whitlatch, 1982). Because the complexity 

of soft-sediment communities may defy any simple paradigm relating to any single factor, Hall 

(1994) and Snelgrove and Butman (1994) proposed a shift in focus towards understanding 

relationships between organism distributions and the dynamic sedimentary and hydrodynamic 

environments. It is likely that the composition of benthic assemblages is controlled by a wide 

array of physical, chemical, and biological factors that interact in complex ways and are variable 

with time. 

 Removal of sediments from borrow sites can alter seabed topography, creating pits that 

may refill rapidly or cause detrimental impacts for extended periods of time. Borrow sites have 

been known to remain well-defined 8 years after dredging (Marsh and Turbeville, 1981; 

Turbeville and Marsh, 1982). Although nearly 12 years may be required for some offshore 

borrow sites to refill to pre-dredge profiles, intentionally locating borrow sites in highly 

depositional areas may dramatically reduce the time for refilling (Van Dolah et al., 1998). In 

general, shallow dredging (<3 m excavation depth) over large areas causes less harm than 

small but deep pits, particularly pits opening into a different substrate surface (Thompson, 1973; 

Applied Biology, Inc., 1979). Deep pits also can hamper commercial trawling activities and 

harm level-bottom communities (Thompson, 1973). If borrow pits are deep, current velocity is 

reduced at the bottom, which can lead to deposition of fine particulate matter and in turn a 

biological assemblage much different in composition than the original. Recovery of the physical 

environment and benthic assemblages to pre-dredging conditions will probably take decades for 

a deep pit dredged 3.6 km offshore Coney Island (Barry A. Vittor & Associates, Inc., 1999). 

Deep holes may decrease dissolved oxygen to hypoxic or anoxic levels and increase hydrogen 

sulfide levels (Murawski, 1969; Saloman, 1974; National Research Council, 1995). 
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 Seabed topography and benthic communities can be altered when sediment is removed 

by dredging bathymetric peaks such as ridges or shoals rather than level sea bottoms or 

depressions. Little information exists regarding the relationship between biological 

assemblages and removal of shoals by dredging. Numerous benthic organisms and fishes 

inhabit offshore shoal areas, but specifics regarding species, assemblages, and ecological 

interrelationships between the topographic features and associated biota are not well known. 

Potential long-term physical and biological impacts could occur if dredging significantly changes 

the physiography of shoals. The MMS has funded a study off Maryland and Delaware to 

address environmental questions concerning use of shoals by fishes and mobile species, 

potential impacts to these species from offshore sand dredging, and ways to preclude or 

minimize long-term impacts. Burlas et al. (2001) monitored borrow sites with bathymetric high 

points off northern New Jersey and found that essentially all infaunal assemblage patterns 

recovered within one year after dredging disturbance except recovery of average sand dollar 

weight and biomass composition, which required 2.5 years. 

7.5.1.2 Sediment Suspension/Dispersion 

 Dredging causes suspension of sediments, which increases turbidity over the bottom. 

This turbidity undergoes dispersion in a plume that drifts with the water currents. The extent of 

suspension/dispersion depends on the type of dredging equipment, techniques for operating the 

equipment, amount of dredging, thickness of the dredged layer, sediment composition, 

sediment transport processes, etc. 

 Herbich and Brahme (1991) and Herbich (1992) reviewed sediment suspension caused 

by existing dredging equipment, and discussed potential technologies and techniques to reduce 

suspension and the associated environmental impacts. In general, cutterhead suction dredges 

produce less turbidity than hopper dredges. A cutterhead suction dredge consists of a rotating 

cutterhead, positioned at the end of a ladder, that excavates the bottom sediment. The 

cutterhead is swung in a wide arc from side to side as the dredge is stepped forward on pivoting 

spuds, and the excavated material is lifted from the bottom by a suction pipe and transferred by 

pipeline as a slurry (Hrabovsky, 1990; LaSalle et al., 1991). Sediment suspension is caused by 

the rotating action of the cutterhead and the swinging action of the ladder (Herbich, 1992). A 

properly operated cutterhead dredge can limit sediment suspension to the lower portion of the 

water column (Herbich and Brahme, 1991; Herbich, 1992). A well-designed cutterhead, 

selection of an appropriate cutterhead for a given sediment, the correct relationship between 

rotational speed of the cutterhead and the magnitude of hydraulic suction, and suitable swing 

rate of the cutterhead, along with hooded intakes, may reduce turbidity at the cutterhead, 

although these conditions are rarely achieved (Herbich, 1992). Measurements around properly 

operated cutterhead dredges show that elevated levels of suspended sediments can be 

confined to the immediate vicinity of the cutterhead and dissipate rapidly with little turbidity 

reaching surface waters (Herbich and Brahme, 1991; LaSalle et al., 1991; Herbich, 1992). 

Maximum suspended sediment concentrations typically occur within 3 m above the cutterhead 

and decline exponentially to the sea surface (LaSalle et al., 1991). Suspended sediment 

concentrations in near-bottom waters may be elevated up to several hundred meters laterally 

from the cutterhead location (LaSalle et al., 1991). 

 A hopper dredge consists of one, two, or more dragarms and attached dragheads 

mounted on a ship-type hull or barge with hoppers to hold the material dredged from the bottom 

(Herbich and Brahme, 1991). As the hopper dredge moves forward, sediments are hydraulically 

lifted through the dragarm and stored in hopper bins on the dredge (Taylor, 1990; LaSalle et al., 

1991). Hopper dredging operations produce turbidity as the dragheads are pulled through 

bottom sediments. However, the main source of turbidity during hopper dredging operations is 
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sediment release during hopper overflow (Herbich and Brahme, 1991; LaSalle et al., 1991; 

Herbich, 1992). A plume may occasionally be visible at distances of 1,200 m or more (LaSalle 

et al., 1991). 

 Much attention has been given to turbidity effects from dredging, although most reviews 

have concerned estuaries, embayments, and enclosed waters (e.g., Sherk and Cronin, 1970; 

Sherk, 1971; Sherk et al., 1975; Moore, 1977; Peddicord and McFarland, 1978; Stern and 

Stickle, 1978; Herbich and Brahme, 1991; LaSalle et al., 1991; Kerr, 1995; Wilber and Clarke, 

2001). Turbidity effects may be less important in unprotected offshore areas for several 

reasons. Offshore sands tend to be coarser with less clay and silt than inshore areas. The 

open ocean environment also provides more dynamic physical oceanographic conditions, which 

minimize settling effects. In addition, offshore organisms are adapted to sediment transport 

processes, which create scouring, natural turbidity, and sedimentation effects under normal 

conditions. Impacts should be evaluated in light of natural variability as well as high level 

disturbances associated with such events as storms, trawling, floods, hypoxia/anoxia, etc. 

(Herbich, 1992). Physical disturbance of the bottom and resulting biological impacts from 

dredging are similar to those of storms and trawling but at a much smaller spatial scale. 

 Turbidity interferes with the food gathering process of filter feeders and organisms that 

feed by sight by inundation with nonnutritive particles. Large quantities of bottom material 

placed in suspension decrease light penetration and change the proportion of wavelengths of 

light reaching the bottom, leading to decreases in photosynthetic activity. Suspension and 

dispersion of sediments may cause changes in sediment and water chemistry as nutrients and 

other substances are released from the substratum and dissolved during the dredging process. 

For aggregate mining operations using hopper dredges, the far-field visible plume contains an 

organic mixture of fats, lipids, and carbohydrates from organisms entrained and fragmented 

during the dredging process and discharged with the overflow (Coastline Surveys Limited, 1998; 

Newell et al., 1999). Dredging may produce localized hypoxia or anoxia in the water column 

due to oxygen consumption of the suspended sediments (LaSalle et al., 1991). Suspension and 

dispersion processes also uncover and displace benthic organisms, temporarily providing extra 

food for bottom feeding species (Centre for Cold Ocean Resources Engineering, 1995). 

7.5.1.3 Sediment Deposition 

 Suspended sediments settle and are deposited nearby or some distance from dredged 

sites. The extent of deposition and the boundaries of biological impact are dependent on the 

type and amount of suspended sediments and physical oceanographic characteristics of the 

area. 

 Dredging effects are not necessarily limited to the borrow site alone. The types of far-field 

impacts from suspension and deposition of sediments can be detrimental or beneficial. 

Deposition of sediments can suffocate and bury benthic fauna, although some organisms are 

able to migrate vertically to the new surface (Maurer et al., 1986). Johnson and Nelson (1985) 

found decreases in abundances and numbers of taxa at nondredged stations, although these 

decreases were not as extreme as those observed in the borrow site. McCaully et al. (1977; as 

cited by Johnson and Nelson, 1985) also observed that dredging effects can extend to other 

nearby areas, and noted decreases in abundance ranging from 34% to 70% at undredged 

stations within 100 m of a dredged site. Conversely, benthos may show an increase in 

biodiversity downstream from dredged sites (Centre for Cold Ocean Resources Engineering, 

1995). In some areas, population density and species composition of benthic invertebrates 

increased rapidly outside dredged sites, with the level of enhancement decreasing with 

increasing distance from the dredged site up to a distance of 2 km (Stephenson et al., 1978; 
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Jones and Candy, 1981; Poiner and Kennedy, 1984). The enhancement was ascribed to the 

release of organic nutrients from the dredge plume, a process known from other studies (Ingle, 

1952; Biggs, 1968; Sherk, 1972; Oviatt et al., 1982; Coastline Surveys Limited, 1998; Newell et 

al., 1998, 1999). This suggestion was supported by records of nutrient releases from benthic 

areas during intermittent, wind-driven bottom resuspension events (Walker and O’Donnell, 

1981), significant increases in nutrients in the water column from simulated storm events in the 

laboratory (Oviatt et al., 1982), and review of the literature indicating a major restructuring force 

in infaunal communities is the response of species to resources released from the sediments by 

periodic disturbance (Thistle, 1981). Fishing also may improve temporarily down current of the 

dredging site and continue for some months (Centre for Cold Ocean Resources Engineering, 

1995). 

7.5.2 Recolonization Rate and Success 

7.5.2.1 Adaptations for Recolonization and Succession 

 In dynamic areas that undergo frequent perturbations, benthic invertebrates tend to be 

small bodied, short lived, and adapted for maximum rate of population increase with high 

fecundity, efficient dispersal mechanisms, dense settlement, and rapid growth rates (MacArthur, 

1960; MacArthur and Wilson, 1967; Odum, 1969; Pianka, 1970; Grassle and Grassle, 1974). In 

contrast, organisms in stable areas tend to be relatively larger and longer lived with low 

fecundity, poor dispersal mechanisms, slow growth rates, and adaptations for non-reproductive 

processes such as competition and predator avoidance. Recolonization of a disturbed area 

often is initiated by organisms that have the adaptive characteristics for rapid invasion and 

colonization of habitats where space is available due to some natural or man-induced 

disturbance. These early colonizers frequently are replaced during the course of succession 

through competition by other organisms, unless the habitat is unstable or frequently perturbed. 

 Although the distinction between the adaptive strategies is somewhat arbitrary and is 

blurred in habitats that are subject to only mild disturbance, the lifestyle differences are 

fundamentally important because they help explain variations in succession and recolonization 

rate and success following disturbance (Coastline Surveys Limited, 1998; Newell et al., 1998). 

Knowledge of faunal component lifestyles allows some predictions of dredging impacts and 

subsequent recolonization and recovery of community composition (Coastline Surveys Limited, 

1998; Newell et al., 1998). 

7.5.2.2 Successional Stages 

 When discussing succession in soft bottom habitats, it is important to point out that most 

of the past studies have concerned silt-clay bottoms rather than sand habitats. Little is known 

about succession in sand bottoms of offshore borrow areas. 

 Successional theory states that organism-sediment interactions result in a predictable 

sequence of benthic invertebrates belonging to specific functional types following a major 

seafloor disturbance (Rhoads and Germano, 1982, 1986). Because functional types are the 

biological units of interest, the succession definition does not rely on the sequential appearance 

of particular species or genera (Rhoads and Boyer, 1982). This continuum of change in benthic 

communities has been divided arbitrarily into three stages (Rhoads et al., 1978; Rhoads and 

Boyer, 1982; Rhoads and Germano, 1982): 

Stage I is the initial pioneering community of tiny, densely populated organisms that 

appears within days of a natural or anthropogenic disturbance. Stage I 

communities are composed of opportunistic species that have high tolerance for 
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and can indicate disturbance by physical disruption, organic enrichment, and 

chemical contamination of sediments. The organisms have high rates of 

recruitment and ontogenetic growth. Stage I communities tend to physically 

bind sediments, making them less susceptible to resuspension and transport. 

For example, Stage I communities often include tube-dwelling polychaetes or 

oligochaetes that produce mucous to build their tubes, which stabilizes the 

sediment surface. Stage I communities include suspension or surface depositfeeding animals that feed at or near the sediment-water interface. The Stage I 

initial community may reach population densities of 104

 to 106 individuals per m2; 

Stage II is the beginning of the transition to burrowing, head-down deposit feeders that 

rework the sediment deeper with time and mix oxygen from the overlying water 

into the sediment. Stage II animals may include tubiculous amphipods, 

polychaetes, and mollusks. These animals are larger and have very low 

population densities compared to Stage I animals; and 

Stage III is the mature and stable community of deep-dwelling, head-down deposit 

feeders. In contrast to Stage I organisms, these animals rework the sediments 

to depths of 3 to 20 cm or more, loosening the sedimentary fabric and 

increasing the water content of the sediment. They also actively recycle 

nutrients because of the high exchange rate with the overlying water resulting 

from their burrowing and feeding activities. The presence of Stage III taxa can 

be a good indication that the sediment surrounding these organisms has not 

been severely disturbed recently, resulting in high benthic stability and health. 

Loss of Stage III species results in the loss of sediment stirring and aeration and 

may be followed by a build-up of organic matter (eutrophication) of the 

sediment. Because Stage III species tend to have relatively low rates of 

recruitment and ontogenetic growth, they may not reappear for several years 

once they are excluded from an area. These inferences are based on past 

work, primarily in temperate latitudes, showing that Stage III species are 

relatively intolerant to physical disturbance, organic enrichment, and chemical 

contamination of sediments. Population densities are low (10 to 102

 individuals 

per m2

) compared to Stage I. 

 The general pattern of succession of benthic species in a marine sediment following 

cessation of dredging or other environmental disturbance begins with initial recolonization. 

Initial recolonization occurs relatively rapidly by small opportunistic species that may reach peak 

population densities within months of a new habitat becoming available after catastrophic 

mortality of the previous assemblage. As the disturbed area is invaded by additional larger 

species, the population density of initial colonizers declines. This transitional period and 

assemblage with higher species diversity and a wide range of functional types may last for 

years, depending on numerous environmental factors. Provided environmental conditions 

remain stable, some members of the transitional assemblage are eliminated by competition, and 

the species assemblage forms a recovered community composed of larger, long-lived, and slow 

growing species with complex biological interactions with one another. 

7.5.2.3 Recolonization Rates 

 The rate of recolonization is dependent upon numerous physical and biological factors 

and their interactions. Physical factors include the time of year, depth of the borrow site, water 

currents and water quality, sediment composition, bedload transport, temperature and salinity, 
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natural energy levels in the area, frequency of disturbance, latitude, etc. Recovery times may 

be shorter in warmer waters at lower latitudes as compared to colder waters at higher latitudes 

(Coastline Surveys Limited, 1998; Newell et al., 1998). 

 Recolonization of borrow sites may occur by transport of larvae from neighboring 

populations by currents and subsequent growth to adults, immigration of motile species from 

adjacent areas, organisms contained in sediment slumping from the sides of pits, or return of 

undamaged organisms from the dredge plume. The rate of recolonization depends on the size 

of the pool of available colonists (Bonsdorff, 1983; Hall, 1994). Other biological factors such as 

competition and predation also determine the rate of recolonization and the composition of 

resulting benthic communities. Timing of dredging is important because many benthic species 

have distinct peak periods of reproduction and recruitment. Because larval recruitment and 

adult migration are the primary recolonization mechanisms, biological recovery from physical 

impacts generally should be most rapid if dredging is completed before seasonal increases in 

larval abundance and adult activity (Herbich, 1992). Recovery of a community disturbed after 

peak recruitment, therefore, will be slower than one disturbed prior to peak recruitment (LaSalle 

et al., 1991). 

 Benthic recolonization and succession have been reviewed to varying extents for a wide 

variety of habitats throughout the world (e.g., Thistle, 1981; Thayer, 1983; Hall, 1994; Coastline 

Surveys Limited, 1998; Newell et al., 1998). Recolonization is highly variable and ranges from 

within months (e.g., Saloman et al., 1982) to more than 12 years (e.g., Wright, 1977), depending 

on the habitat type and other physical and biological factors. Focusing on dredging, Coastline 

Surveys Limited (1998) and Newell et al. (1998) suggested that, in general, recovery times of 6 

to 8 months are characteristic for many estuarine muds, 2 to 3 years for sand and gravel, and 5 

to 10 years as the deposits become coarser. For offshore dredging of borrow sites in 10 to 

20 m water depths for renourishment of Dare County, NC beaches, the USACE (2000) stated 

that recolonization of affected areas is expected within 2 to 3 years. 

 The Centre for Cold Ocean Resources Engineering (1995) estimated times for recovery of 

a reasonable biodiversity (number of species and number of individuals) based on sediment 

type. In this study, recovery was defined as attaining a successional community of opportunistic 

species providing evidence of progression towards a community equivalent to that previously 

present or at non-impacted sites. Fine-grained sediments may need only one year before 

achieving a recovery level biodiversity, medium-grained deposits 1 to 3 years, and coarsegrained deposits 5 or more years. For a hypothetical borrow site dredging scenario off Ocean 

City, Maryland, the Centre for Cold Ocean Resources Engineering (1995) stated that virtually all 

benthic species would be lost, but there may be temporary improvement of fishing due to 

release of nutrients. Recolonization would start within weeks of closure and moderate 

biodiversity would occur within one year. The borrow site would be colonized initially by a very 

different species complex than originally present. An estimate of 2 to 3 years was given for the 

community to begin to show succession to pre-impact sand habitat species. 

 Studies of recolonization listed and discussed by Grober (1992) and the National 

Research Council (1995) indicate that recolonization of offshore borrow sites is highly variable. 

This variability is not surprising considering the differences between studies in geographic 

locations, oceanographic conditions, sampling methods and times, etc. Part of the problem in 

determining recolonization patterns is seasonal and year to year fluctuations in benthic 

community characteristics and composition. Without adequate seasonal and yearly data prior to 

dredging, it is difficult to determine whether differences in community characteristics and 

composition are due to temporal changes or dredging disturbance. 
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 Results and conclusions from these offshore borrow site studies indicate that 

recolonization usually begins soon after dredging ends. Recolonization periods range in 

duration from a few months to possibly decades for deep pits. Although abundance and 

diversity of benthic fauna within the borrow sites often returned to levels comparable to 

pre-dredging or reference conditions within less than one year, several studies documented 

changes in benthic species composition that lasted much longer, particularly where sediment 

composition was altered (e.g., Johnson and Nelson, 1985; Bowen and Marsh, 1988; Van Dolah 

et al., 1992, 1993; Wilber and Stern, 1992; Barry A. Vittor & Associates, Inc., 1999). 

 Most recolonization studies of borrow sites concentrated on three main features of 

infaunal communities, namely the number of individuals (population density), number of species 

(diversity), and weight (biomass as an index of growth). Dredging is usually accompanied by an 

immediate and significant decrease in the number of individuals, species, and biomass of 

benthic infauna. Using biological community parameters (e.g., total taxa, total number of 

individuals, species diversity, evenness, richness, etc.), previous studies tend to indicate that 

recovery of borrow sites occurs in approximately one year after dredging. However, these 

parameters do not necessarily reflect the complex changes in community structure and 

composition that occur during the recovery process. Major changes in species assemblages 

and community composition usually occur shortly after dredging such that a different type of 

community exists. Although the number of individuals, species, and biomass of benthic infauna 

may approach pre-dredging levels within a relatively short time after dredging, recovery of 

community composition may take longer. 

7.5.2.4 Recolonization Success and Recovery 

 Assessing impacts of dredging and recolonization and recovery of borrow sites is difficult 

because most biological communities are complex associations of species that often undergo 

major changes in population densities and community composition, even in areas that are far 

removed and unaffected by dredging and other disturbances. Recolonization success and 

recovery do not necessarily mean that communities should be expected to return to the predredged species composition. To gauge recovery, it is important to compare the community 

composition of dredged sites with control areas during the same seasons because community 

composition changes with time. 

 When long-term alterations in sediment structure and composition occur as a result of 

dredging, long-term differences in the composition of benthic assemblages inhabiting those 

sites may occur as well. The recovery time of benthic assemblages after dredging can depend 

in large measure on the degree and duration of sediment alteration from sand borrowing (Van 

Dolah, 1996). Recolonization success and recovery also are controlled by compaction and 

stabilization processes involving complex interactions between particle size, water currents, 

waves, and biological activities of the benthos following sediment deposition (Oakwood 

Environmental Ltd., 1999). While the abundance and diversity of infaunal assemblages may 

recover relatively rapidly in dredged sites, it may take years to recover in terms of sediment and 

species composition. 

 One conclusion commonly held is that perturbations to infaunal communities in borrow 

sites are negligible because organisms recolonize rapidly (Wilber and Stern, 1992). This 

conclusion often is based on measures including densities, species diversity/evenness indices, 

relative distribution of classes or phyla, and species-level dendrograms. For example, many 

researchers have recognized that borrow site and reference area infaunal communities can 

differ considerably at the species level, although these differences usually are considered 

insignificant because species diversity is high. According to Wilber and Stern (1992), reliance 
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on these studies may lead to a premature conclusion that impacts to borrow site infauna are 

minimal because these measures are relatively superficial and ambiguous characteristics of 

infaunal communities. Wilber and Stern (1992) reexamined infaunal data from four borrow site 

projects by grouping species into functional groups called ecological guilds based on similarities 

in feeding mode, locomotory ability, and sediment depth occurrence. Their analyses showed 

that infaunal communities in borrow and control areas can differ in several ways and that these 

differences can last several years. Polychaetes and amphipods that recolonize borrow sites are 

small-bodied and confine their movement and feeding to the surface sediment or the interface 

between the sediment and water column. In contrast, control areas have well-developed 

infaunal communities commonly consisting of large-bodied organisms that move and feed deep 

in the sediment (Wilber and Stern, 1992). They concluded that infaunal communities 

recolonizing borrow sites may remain in an early successional stage for 2 to 3 years or longer 

as opposed to being completely recovered in shorter time frames. 

 The conclusions of Wilber and Stern (1992) coincide with the model of succession 

discussed previously. The model states pioneering or opportunistic species are the first to 

colonize an area after a physical disturbance to the bottom (e.g., dredging borrow sites). 

Pioneering species tend to share several ecological traits, including a tendency to confine 

activities to the sediment-water interface, possibly because subsurface conditions cannot 

support a significant number of organisms. The subsurface environment changes with time 

after the disturbance, possibly by actions of early colonizers, and becomes suitable for deposit 

feeders and mid-depth burrowers. The relative absence of deposit feeders and mid-depth 

burrowers is interpreted to mean an area is still in the state of recovery. 

 Although most of the literature on recolonization rate and success in borrow sites 

concerns infauna, some information exists for epifauna. The numbers of taxa and individuals 

collected by trawls in a borrow site off Duval County, Florida greatly exceeded the control area 

numbers 4 months after dredging and were generally higher 7 and 13 months after dredging 

(Applied Biology, Inc., 1979). There were no detectable differences between pre-dredging and 

post-dredging (8 and 16 months) epifaunal communities in a borrow site surveyed by otter trawl 

and video camera off Egmont Key, Florida (Blake et al., 1995). 

7.5.3 Predictions Relative to the Sand Resource Areas 

7.5.3.1 Potential Benthic Effects 

Sediment Removal 

 The immediate impact of excavating upper sediments of a sand resource area would be 

removal of portions of the benthic invertebrate populations that inhabit surficial shelf sediments. 

Lost individuals would be those with slow-moving or sessile lifestyles, primarily those comprising 

infaunal populations. Surveys within and adjacent to each of the four North Carolina sand 

resource areas, as well as benthic investigations of nearby waters, reveal that benthic 

invertebrate assemblages of inner shelf waters of the study region predominantly are 

invertebrates, including crustaceans, echinoderms, mollusks, and polychaetous annelids. 

 The expected loss of benthic fauna due to sediment excavation from the sand resource 

areas could be considered to represent a negligible impact on the ecosystem when evaluating 

the impact on a spatial scale. Specific shoals within each resource area are targeted for 

excavation based on particular sedimentary and bathymetric characteristics, leaving a 

significant extent of non-dredged areas surrounding the borrow sites. These undisturbed areas 

would be a primary source of colonizing fauna for the excavated sites (Van Dolah et al., 1984), 

and would complement colonization of altered substrata via larval recruitment. The great 
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densities and fecundity of invertebrate populations, along with the relatively small areas of 

impact proposed, would preclude significant long-term negative effects on benthic populations. 

Impacts most likely would be localized and short-term. 

 Correlation between sediment composition and the composition of infaunal assemblages 

has been demonstrated in numerous environmental surveys, including the 1998 surveys of the 

North Carolina sand resource areas. Invertebrate populations inhabiting marine soft bottoms 

offshore North Carolina exhibit heterogeneous distributions that largely are the result of local 

sedimentary regime. Modification of surficial sediments and local bathymetry could result in an 

alteration of the areal extent and relative distribution of infaunal assemblage types by altering 

the distribution of sediment types capable of supporting those assemblages. 

 It is possible that a change in the composition of surficial sediments within excavated 

areas could become a long-term result of dredging. Several factors could contribute to such an 

outcome, primarily the type of sediments exposed by dredging, the degree of deposition of fine 

sediments into dredged sites, and bathymetric alteration that results in hypoxic or anoxic 

conditions. These factors would depend primarily on the depth of excavation, which would be 

determined by the vertical relief of the sand shoal to be excavated, the vertical extent of those 

sediments suitable for coastal nourishment projects, and the volume of sand required. 

 Because the inner shelf ecosystem of the Middle Atlantic Bight exhibits some 

heterogeneity in sediment types and their associated assemblages, those infaunal assemblages 

that initially colonize dredged sites likely would be similar to some naturally occurring 

assemblages that inhabit nearby non-dredged sites, especially areas with finer sediments. 

When viewed within a context of scale, removal of sediments from portions of the North 

Carolina inner continental shelf would at most minimally alter the existing spatial balance of 

habitat (sediment) types. Moreover, those habitats that have relatively high amounts of finer 

sediments are not uninhabitable, or necessarily less functional in an ecological sense, when 

compared to sand or gravel substrata. Various sedimentary habitats merely differ in their level 

of suitability for certain types of infaunal taxa. Changes in habitat suitability that result from 

sand removal likely would be ephemeral and inconsequential in the shelf ecosystem, a system 

where both infaunal assemblage types and sedimentary parameters often are temporally and 

spatially variable. 

 Motile populations, including non-migratory foragers, would be less stressed by sediment 

removal than infauna or sessile epifauna. Most macroepifaunal and demersal fish populations 

would have a low probability of being adversely impacted directly by the dredging of surficial 

sediments. Slow-moving or burrowing sessile epifauna inhabiting the project area include 

echinoderm and decapod taxa, and local populations of these types of benthic organisms would 

most likely experience a reduction in density due to sediment removal. Motile epifauna 

generally are migratory and are not endemic to the borrow sites. Most demersal populations 

exhibit naturally dynamic distributions, moving between areas within the Middle Atlantic Bight on 

a seasonal basis (MMS, 1989). 

 Any impacts of sediment removal on epifaunal and demersal taxa likely would be indirect 

in nature, through habitat alteration. A reduction of infaunal biomass resulting from sediment 

removal could have an indirect effect upon the distribution of certain demersal fishes and other 

epibenthic predators by interrupting established energy pathways to the higher trophic levels 

represented by these foraging taxa. Reductions in densities of the preferred prey of bottomfeeding taxa could induce migration of foragers to unimpacted areas. However, a relatively 

small percentage of infaunal prey items that typically are consumed by demersal taxa would be 

rendered unavailable for consumption as a result of prey removal along with sediments. 

Benthic predators simply would select alternative areas in which to forage. Because excavated 
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areas are expected to recover relatively rapidly after dredging, loss of infaunal biomass due to 

sediment excavation is unlikely to adversely affect normal energy flow through North Carolina 

inner shelf sand bottoms. 

 In addition to widely documented spatial variation, the location and extent of some inner 

shelf-inhabiting infaunal and demersal populations vary seasonally in the study region. 

Seasonal variability should be considered when evaluating potential impacts from sand removal. 

The timing of sand removal would seem to be less critical for minimizing the impact upon 

infauna than for other faunal categories of concern (e.g., key pelagic species), due to the great 

abundance and reproductive potential of infaunal populations. Many numerically dominant 

infaunal taxa inhabiting the study region are known to exhibit either year-round or late winterearly spring periods of recruitment. Because of these patterns of recruitment and lower winter 

densities, removal of sand between late fall and early spring would result in less stress on 

benthic populations. 

Sediment Suspension/Dispersion 

 Whether cutterhead suction dredging or hopper dredging ultimately is utilized for sand 

mining, the amount of sediment suspension that results from these excavation methods is not 

anticipated to be of a scale that would cause significant negative impacts to the benthic 

community. North Carolina sand resource areas are characterized by a relatively limited 

amount of very fine sediments, indicating that the area encompassing those resource areas 

currently is not a depositional environment, but is hydrologically dynamic. In general, benthic 

assemblages of the inner North Carolina shelf probably are adapted to periodic reworking of 

surficial sediments caused by tropical and extra-tropical storms. Impacts of dredging-induced 

elevations in turbidity (associated mainly with hopper dredging) would be short-term and 

localized. Motile taxa could avoid turbid areas, and are unlikely to be affected by sediment 

resuspension. 

Sediment Deposition 

 Of the various faunal categories, infaunal and sessile epifaunal populations would be most 

negatively affected by significant deposition of sediments; however, efficient methods of 

sediment excavation would preclude all but a relatively minor amount of sediment deposition. 

Suspension and transport of sediments away from dredging sites should be minimal and any 

subsequent deposition will be insignificant in degree. In the unlikely event that significant 

dredging-related deposition of fine-grained sediments were to occur, the deposited sediments 

likely would not persist on the seafloor because of the high-energy inner shelf environment. 

However, some low or depressional areas of the seafloor could exhibit a substantial deposition 

of fine sediments under this scenario. Given the relatively small amount of sediment 

suspension anticipated to occur during dredging, the degree of burial should be substantially 

less than would be required to impact negatively on infaunal populations. 

7.5.3.2 Potential Recolonization Rate and Success 

 The rate and nature of post-dredging recovery of benthic assemblages within an 

excavated borrow site will depend primarily on the depth of sand excavation. While surface 

area of impact could be minimized by excavating a shoal to a greater depth, deep excavation 

likely would require a greater length of time for complete recovery of infaunal assemblages 

within the impacted area. The creation of a bathymetrically abrupt pit has potential to inhibit 

water current flow through such a feature, possibly resulting in a “dead zone” characterized by 

deposition of fine particles and hypoxia or anoxia. This scenario would extend the duration of 
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ecological impact beyond that which would occur with a more shallow cut over a much larger 

area. 

 Recent results of long-term environmental monitoring of a borrow site located 3.6 km 

offshore Coney Island have demonstrated potential consequences of dredging an abrupt pit 

feature (Barry A. Vittor & Associates, Inc., 1999). A nearby reference area also was sampled 

before (1992) and after dredging (1995 through 1998). Prior to dredging, average water depths 

were approximately 3 to 4 m at the Coney Island borrow site and in the reference area. After 

the last dredging in 1995, and up until the last monitoring event (1998), depths of borrow site 

stations varied from 6 to 15 m, while the average depth of reference area stations did not 

change during the study period. Prior to dredging, sediments at the borrow site were 55% 

medium to coarse sands, but by 1995 were fine to medium sands (<20% medium to coarse 

sand). By 1998, the silt/clay fraction (>20%) of borrow site sediments was significantly greater 

than in reference area sediments (4%). During each year following the last dredging event, 

infaunal assemblage composition at the borrow site was numerically dominated by depositfeeding polychaetes (Spio setosa and Streblospio benedicti) and mollusks (primarily Tellina 

agilis); none of these species were ever observed in the reference area. Although hypoxic 

conditions have not been detected at the Coney Island borrow site, bathymetric alteration and 

subsequent deposition of fine sediments resulted in persistent alteration of natural assemblage 

composition. 

 While the initial impact on benthic assemblages would increase with a greater surface 

area of sand removal, the persistence of ecological impact that would occur with a relatively 

shallow excavation would be less than that of a deep pit. A maximum shoal excavation of 2 m 

(Areas 3 east and 4) or 3 m (Areas 1, 2, and 3 west) will result in little long-term impact because 

a more smoothly-graded, trough-like feature would allow greater bottom current flow. North 

Carolina sand resource areas exhibit natural inter-ridge trough features. These bathymetric 

depressions can be depositional areas for fine sediments and often support benthic 

assemblages that are different from nearby assemblages inhabiting gravel and sand. 

Ultimately, though, it is expected that only the leading edge of each shoal will be dredged and 

that depth of dredging will not substantially exceed the level of the ambient shelf surface. 

 The length of time required for reestablishment of pre-dredging infaunal assemblages 

within excavated sites partly depends on the length of time required for refilling of those mined 

areas. The relatively shallow water benthic habitats of the North Carolina inner shelf are 

strongly influenced by factors such as tidal currents and circulation, and storms. These same 

forces would tend to modify impacted sites in the direction of pre-dredging conditions. The rate 

of reestablishment of natural benthic conditions at dredged sites may depend especially on the 

extent of storm-induced sediment transport, which can be substantial at relatively shallow 

depths such as those in the region of the sand resource areas. 

 Assuming that the depth of sand excavation will not be so great as to substantially alter 

local hydrological characteristics, removal of benthic organisms along with sediments would be 

quickly followed by initial recolonization of the dredged sites by opportunistic infaunal taxa. 

Early-stage succession will begin within days of sediment removal, through settlement of larval 

recruits, primarily annelids and bivalves. Initial larval recruits likely would be dominated by 

populations of deposit feeding, opportunistic taxa, especially polychaetes and bivalves such as 

Solemya velum and Tellina agilis. These species are well adapted to environmental stress and 

exploit suitable habitat when it becomes available. Later successional stages of benthic 

recolonization will be more gradual, and involve taxa that generally are less opportunistic and 

longer lived. Immigration of motile annelids, crustaceans, and echinoderms into impacted areas 

also will begin soon after excavation. 
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 The length of time required to reestablish infaunal assemblages also depends in large 

measure on the sediments exposed by dredging. Shoal sediments consist of well-sorted sands 

and also appear to be vertically uniform in composition. Sediments exposed by dredging 

probably will not differ substantially from existing surficial sediments In addition, the resource 

areas are characterized by a limited amount of fine sediments, indicating that they are not 

depositional in nature. Later stages of recolonization in dredged sites likely will occur in a timely 

manner and without persistent inhabitation by initial transitional assemblages, not unlike the 

process which has been documented elsewhere in the Middle Atlantic Bight (Kropp, 1995; Scott 

and Kelly, 1998). 

 Because the sedimentary regime of North Carolina sand resource areas is vertically 

uniform, recolonization of surficial sediments by later successional stages likely will proceed 

even if dredged shoals are not completely reestablished. Furthermore, dredging of only a small 

portion of the area within each of the resource areas will ensure that a supply of nontransitional, motile taxa will be available for rapid migration into dredged sites. While community 

composition may differ for a period of time after the last dredging, the infaunal assemblage type 

that exists in mined areas will be similar to naturally occurring assemblages in the study area, 

particularly those assemblages inhabiting inter-ridge troughs. Based on previous observations 

of infaunal reestablishment in dredged sites, the infaunal community in dredged sites most likely 

will become reestablished within 2 years, and will exhibit levels of infaunal abundance, diversity, 

and composition comparable to nearby non-dredged sites. 

7.6 PELAGIC ENVIRONMENT 

 This section discusses the potential effects of hydraulic (cutterhead and hopper) dredging 

on water column organisms at a borrow site, and seasonal windows that would reduce the 

effects to particular species or groups. Groups of organisms considered include zooplankton 

(including eggs and larvae of economically important fish and shellfish species), squids, pelagic 

fishes, sea turtles, and marine mammals. 

7.6.1 Zooplankton 

7.6.1.1 Entrainment 

 Zooplankters encountering the suction field of hydraulic dredges will be easily drawn into 

the system (i.e., entrained). Entrained zooplankters are assumed to die from abrasion and 

physical trauma (LaSalle et al., 1991; Reine and Clarke, 1998). The most detrimental 

consequence of zooplankton entrainment is the death of fish and invertebrate larvae, which 

ultimately influences the age structure of adult populations. 

 The rate of zooplankton entrainment by hydraulic dredges depends upon local 

hydrographic patterns responsible for their transport and the spatial and temporal dynamics of 

local populations. Hydrographic patterns can be measured, whereas inherently variable 

zooplankton populations are more difficult to characterize (Sullivan and Hancock, 1977). 

Because of difficulties in measuring population parameters from field-collected data, direct 

estimates of zooplankton entrainment (and subsequent population effects) are not available in 

the dredging literature. An alternative to using field-collected data has been to develop 

numerical models that predict population effects given specific scenarios (discussed in LaSalle 

et al., 1991 and Reine and Clarke, 1998). Unfortunately, population effects estimated from 

models can differ greatly depending upon model assumptions (LaSalle et al., 1991; Reine and 

Clarke, 1998). 
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 Entrainment rate also depends upon physical aspects of the dredging operation. Because 

the suction field of hydraulic dredges remains near the seafloor, species most susceptible to 

entrainment are those occurring in the lower portion of the water column. Taxa or life stages 

that spend part of their time associated with the benthic environment, such as demersal fish 

eggs or demersal zooplankton (Hammer and Zimmerman, 1979), would be especially 

vulnerable. Unfortunately, no information exists on the abundance or composition of demersal 

zooplankton in the sand resource areas. Several fish species in the region lay demersal eggs. 

Considering the high reproductive capacity of zooplankton along with the relatively small area of 

the dredge suction field and the volume of water entrained compared to the overall volume of 

surrounding waters, it is unlikely that entrainment would greatly affect zooplankton populations 

or assemblages in the North Carolina sand resource areas.

7.6.1.2 Turbidity 

 Sediments suspended and dispersed by the action of a working dredge can affect 

zooplankters by 1) interfering with feeding activity; 2) direct mortality and toxicity; and 

3) physiological impairment. 

 Most crustacean zooplankters are filter feeders capable of filtering and processing 

particles between 3 and 10 m (Nival and Nival, 1976). Inorganic particles in this size range can 

easily foul the fine structures (setules) on feeding appendages of crustaceans such as 

copepods, and crab and shrimp larvae (Sullivan and Hancock, 1977). Laboratory studies have 

shown that mechanical disruption of feeding can affect growth and reproductive success (Kirk, 

1992). Plankters feeding by ciliary action (e.g., echinoderm larvae) also would be susceptible to 

mechanical effects of suspended particles (Sullivan and Hancock, 1977). 

 Larval fishes are visual feeders that depend on adequate light levels for their foraging 

success (Blaxter, 1968). High turbidity reduces light levels in the water column, which in turn 

shortens the reactive distance between a larval fish and its prey. Laboratory studies have 

demonstrated the negative influence of elevated turbidity on prey capture rates for larvae of the 

herring Clupea harengus harengus (Johnston and Wildish, 1982), striped bass, Morone saxatilis

(Morgan et al., 1983; Breitburg, 1988), and dolphin, Coryphaena hippurus (Jokiel, 1989). In one 

laboratory study, however, increased turbidity actually enhanced feeding abilities of larval 

herring Clupea harengus pallisi (Boehlert and Morgan, 1985). The authors suggested that 

suspended sediment may have provided better contrast against which small particles were 

viewed. 

 Direct mortality and toxicity caused by elevated turbidity varies with species and the 

nature of the sediment and sediment-bound contaminants. Crustacean zooplankters will ingest 

suspended inorganic particles that may or may not contain contaminants. Contamination is 

expected to be low in all sand resource areas. A laboratory study showed that copepods 

ingesting high amounts of “red mud” grew slower than control groups feeding only on diatoms 

(Paffenhofer, 1972). This was attributed to the non-nutritive value of the red mud rather than to 

any associated toxic compounds. Sediment-bound toxic compounds introduced into the water 

column may be ingested by zooplankters. These substances can be detrimental to 

zooplankters. However, studies with copepods exposed to deep sea mine tailings containing 

trace metals showed minimal effects (Hirota, 1981; Hu, 1981). 

 High turbidity can cause physiological changes that can kill or retard developing eggs and 

larvae of fishes and invertebrates (Davis and Hidu, 1969; Rosenthal, 1971). High 

concentrations of suspended sediment can kill or deform fish eggs (Rosenthal, 1971). 

Laboratory studies investigating effects of elevated turbidity on eggs and larvae of bivalves 

show that slight increases in turbidity actually stimulated larval growth, whereas large increases 
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in turbidity caused abnormalities (Loosanoff, 1962; Davis and Hidu, 1969). Hatching success of 

fish eggs exposed to high suspended concentrations varies, but most studies show minimal 

effects from acute exposures in the 50 to 500 mg/L range (Auld and Schubel, 1978; Morgan et 

al., 1983; Jokiel, 1989). In these same studies, artificially high suspended sediment 

concentrations (1,000 to 8,000 mg/L) were required to induce mortality. 

 As with entrainment, the effects of suspended sediments on zooplankters is primarily 

restricted to the lower portion of the water column for a cutterhead dredge because the turbidity 

plume remains near the cutterhead with little of the plume reaching surface waters (LaSalle et 

al., 1991). Suspended sediment plumes in near-bottom waters may extend for up to several 

hundred meters laterally from the cutterhead. In contrast, hopper barges may create turbid 

surface plumes due to overwash (LaSalle et al., 1991). With either dredge type, the turbidity 

plume is expected to cover a small portion of the water column relative to the surrounding 

waters. Due to the limited areal extent and transient nature of the sediment plume, it is unlikely 

that turbidity would greatly affect zooplankton populations or assemblages in the North Carolina 

sand resource areas. 

7.6.1.3 Project Scheduling 

 For open ocean environments, Sullivan and Hancock (1977) generalized that dredging 

effects on zooplankton would be minimal due to high spatial and temporal variability of the 

populations, whereas significant effects would be expected in enclosed waters with endemic 

populations. However, accurate prediction of the local effects of entrainment or dredgeproduced turbidity on zooplankton populations of the sand resource areas requires adequate 

site-specific data. Zooplankton populations in general should not be subject to impacts from 

dredging, but available regional information (see Section 2.3.2.1) indicates that planktonic 

larvae, particularly those of fishes, occur in the project area especially during summer and fall 

months (Able and Fahay, 1998; Grothues and Cowen, 1999). Because adults of these species 

spawn offshore and larval and juvenile forms make their way back to inshore nursery areas 

such as Pamlico Sound through Oregon Inlet (e.g., Warlen and Burke, 1990) Sand Resource 

Area 3 could be construed as lying near an important recruitment corridor. The other sand 

resource sites are not within such an important position relative to coastal inlets and therefore 

should not require any special project scheduling consideration. 

 When data are inadequate to accurately predict the magnitude of dredging effects, 

environmental windows have been required to provide a conservative approach and lessen 

potential effects on key species. However, LaSalle et al. (1991) and Reine et al. (1998) have 

stressed the need to base future environmental windows on sound evidence, and have argued 

against subjectively selected environmental windows. Environmental windows delay projects 

and greatly increase costs (Dickerson et al., 1998), and their use should not be driven by 

subjective or overly conservative approaches. If Area 3 is used as a borrow site, an 

environmental window excluding summer and fall months could be considered to avoid dredging 

when fish juveniles and larvae are most prevalent, but only if additional data become available 

to determine the extent of impacts and justify the restriction. Progress toward understanding the 

real need for environmental windows can only be achieved by reducing the degree of 

uncertainty surrounding impacts and the means to avoid them (Dickerson et al., 1998). 
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7.6.2 Squids 

7.6.2.1 Entrainment 

No information exists regarding impacts of hydraulic dredging on squids. Nevertheless, 

squids could be entrained if they encountered the suction field of a hydraulic dredge. Some 

general aspects of squid behavior increase the chance of encountering the bottom-oriented 

dredge suction field. Adult squids are generally demersal by day and enter the water column at 

night to feed on zooplankton (Fischer, 1978). In addition, squids lay their eggs in large clusters 

on the seafloor (Vecchione, 1981). 

7.6.2.2 Attraction 

 Because some squid species are attracted to lights at night (Fischer, 1978), it is likely that 

squids could be attracted to lights of a working dredge. This could draw them into the suction 

field and increase the chance of entrainment. 

7.6.2.3 Project Scheduling 

 With no information on local squid populations available, reasonable predictions of 

demographic effects are difficult to make. As with the other pelagic organisms, dredging is 

unlikely to significantly impact squid populations in the vicinity of the sand resource sites. This 

precludes the need for an environmental window or specific project scheduling to protect squid 

resources. 

7.6.3 Fishes 

7.6.3.1 Entrainment 

 Entrainment of adult fishes by hydraulic dredging has been reported for several projects 

(Larson and Moehl, 1988; McGraw and Armstrong, 1988; Reine and Clarke, 1998). The most 

comprehensive study of fish entrainment took place in Grays Harbor, Washington during a 

10-year period when 27 fish taxa were entrained (McGraw and Armstrong, 1988). Most 

entrained fishes were demersal species such as flatfishes, sand lance, and sculpin; however, 

three pelagic species (anchovy, herring, and smelt) were recorded. Entrainment rates for the 

pelagic species were very low, ranging from 1 to 18 fishes/1,000 cy (McGraw and Armstrong, 

1988). Comparisons between relative numbers of entrained fishes with numbers captured by 

trawling showed that some pelagic species were avoiding the dredge. Another entrainment 

study conducted near the mouth of the Columbia River, Washington reported 14 fish taxa 

entrained at an average rate of 0.008 to 0.341 fishes/cy (Larson and Moehl, 1988). Few of the 

coastal pelagic fishes occurring offshore North Carolina should become entrained because the 

dredge’s suction field exists near the bottom and many pelagic species have sufficient mobility 

to avoid the suction field. 

7.6.3.2 Attraction 

 Even though dredges are temporary structures, they still can attract roving pelagic 

species. This may temporarily disrupt a migratory route for some members of the stock, but it is 

unlikely that there would be an appreciable negative effect. 

7.6.3.3 Turbidity 

 Turbidity can cause feeding impairment, avoidance and attraction movements, and 

physiological changes in adult pelagic fishes. As discussed for larval fishes, pelagic species are 
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primarily visual feeders. When turbidity reduces light penetration, the fishes’ reactive distance 

decreases (Vinyard and O’ Brien, 1976). Light scattering caused by suspended sediments also 

can affect a visual predator’s ability to perceive and capture prey (Benfield and Minello, 1996). 

 Some species will actively avoid or be attracted to turbid water. Experiments with pelagic 

kawakawa (Euthynnus affinis) and yellowfin tuna (Thunnus albacares) demonstrated that these 

species would actively avoid experimental turbidity clouds, but also would swim directly through 

them during some trials (Barry, 1978). Turbidity plumes emanating from coastal rivers may 

retard or affect movements of some pelagic species. 

 Gill cavities can be clogged by suspended sediment, preventing normal respiration and 

mechanically affecting food gathering in planktivorous species (Bruton, 1985). High suspended 

sediment levels generated by storms have contributed to the death of nearshore and offshore 

fishes by clogging gill cavities and eroding gill lamellae (Robins, 1957). 

 The limited spatial and temporal extents of turbidity plumes from either cutterhead or 

hopper dredges are expected to be limited. Therefore, there should be no significant impact on 

adult pelagic fishes. 

7.6.3.4 Project Scheduling 

 Hydraulic dredging should not present a significant problem for pelagic fishes offshore 

North Carolina. If an environmental window is sought to protect pelagic fishes from dredging 

impacts, the spring to fall period would encompass the peak seasons for the economically 

important species. Temporal scheduling as a means to avoid impacts is practical if the 

organism in question is highly concentrated in waters of the area during some specific time 

period. Quantitative data are lacking to support the use of an environmental window to lessen 

effects on pelagic fishes. 

7.6.3.5 Essential Fish Habitat 

 The Magnuson-Stevens Fishery Conservation and Management Act (16 U.S.C. § 1801-

1882) established regional Fishery Management Councils and mandated that Fishery 

Management Plans (FMPs) be developed to responsibly manage exploited fish and invertebrate 

species in Federal waters of the U.S. When Congress reauthorized this act in 1996 as the 

Sustainable Fisheries Act, several reforms and changes were made. One change was to 

charge the NMFS with designating and conserving Essential Fish Habitat (EFH) for species 

managed under existing FMPs. This was intended to minimize, to the extent practicable, any 

adverse effects on habitat caused by fishing or non-fishing activities, and to identify other 

actions to encourage the conservation and enhancement of such habitat. 

 EFH is defined as “those waters and substrate necessary to fish for spawning, breeding, 

feeding or growth to maturity” [16 U.S.C. § 1801(10)]. The EFH interim final rule summarizing 

EFH regulations (62 FR 66531-66559) outlines additional interpretation of the EFH definition. 

Waters, as defined previously, include "aquatic areas and their associated physical, chemical, 

and biological properties that are used by fish, and may include aquatic areas historically used 

by fish where appropriate." Substrate includes “sediment, hard bottom, structures underlying 

the waters, and associated biological communities.” Necessary is defined as "the habitat 

required to support a sustainable fishery and the managed species' contribution to a healthy 

ecosystem." “Fish” includes "finfish, mollusks, crustaceans, and all other forms of marine 

animal and plant life other than marine mammals and birds," whereas "spawning, breeding, 

feeding or growth to maturity" cover the complete life cycle of those species of interest. 
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 The sand resource areas are within the region managed by the Mid-Atlantic Fishery 

Management Council (MAFMC); however, species included in FMPs by the South Atlantic 

Fishery Management Council (SAFMC) and Highly Migratory Species (HMS) Section of the 

Office of Sustainable Fisheries may occur in this region. Many species managed by these 

Federal groups also are under the purview of the Atlantic States Marine Fisheries Commission. 

The MAFMC produced several FMPs for single and mixed groups of species. All of these FMPs 

were recently amended to address EFH, including those for Atlantic surfclam and ocean quahog 

(MAFMC, 1998a); Atlantic mackerel, squids, and butterfish (MAFMC, 1998b); summer flounder, 

scup, and black sea bass (MAFMC, 1998c); bluefish (MAFMC, 1998d); and spiny dogfish 

(MAFMC, 1999). Amendments identified and described EFH for all life stages of managed 

species. In addition to the FMPs prepared by the MAFMC, the SAFMC prepared a single 

amendment (SAFMC, 1998) to cover a suite of managed species including shrimps, snappergrouper, coastal pelagics, and red drum. Highly migratory species (tunas, sharks, and 

swordfish) are managed by the NMFS (NMFS, 1999). EFH for several species (and life stages) 

covered in these FMPs overlapped the four sand resource areas offshore North Carolina. EFH 

characteristics for these species are presented in Table 7-1. 

 Another EFH process component is designating Habitat Areas of Particular Concern 

(HAPCs). HAPCs are narrowly focused habitats with demonstrated direct habitat value for 

managed species. Several HAPCs are located in North Carolina marine waters and include 

sandy shoals off Cape Hatteras, Cape Fear, and Cape Lookout; Big Rock; Bogue Sound; New 

River; The Point; and Ten Fathom Ledge. None of these HAPCs encompasses the sand 

resource areas; therefore, direct effects from dredging would not be expected. General marine 

HAPCs that overlap or are in the vicinity of the sand resource areas include artificial reefs, 

Sargassum, water column, and hard/live bottom areas that could be affected by dredging. 

 Hard bottom is known to occur off northern North Carolina near the sand resource areas 

(Southeast Area Monitoring and Assessment Program—South Atlantic, 2001), and potential 

hard bottom also has been reported (Boss et al., 1999; Boss and Hoffman, 2001). Sand mining, 

dredge disposal, and anchoring are potential threats to hard/live bottom off North Carolina 

(Moser et al., 1995). Although no indication of hard/live bottom was found during the limited 

biological surveys that focused on soft bottom in the sand resource areas, more extensive 

surveys should be conducted in the future prior to dredging in and near specific borrow sites to 

determine if hard/live bottom is present and if protective measures are necessary. 

Determination of hard/live bottom survey requirements should consider the following three 

statements from Boss et al. (1999). Due to the low-relief and high-energy dynamics of this shelf 

environment, it is probable that these hard bottom areas are transient features of the seafloor. 

Major storms may redistribute sediment on the shelf such that some hard bottom areas will 

become covered, whereas new hard bottom areas will be exhumed. When exposed, these new 

hard bottom sites can be important benthic habitats because they present new space on which 

benthos may become established; however, when covered with even a thin layer (i.e., few cm) 

of loose sediment, they become non-productive (Renaud et al., 1996a,b). Based on these 

statements, if detailed hard/live bottom studies are deemed necessary in and near the sand 

resource areas in the future, it would be advisable to conduct the surveys immediately prior to 

dredging a particular borrow site due to the "probable" ephemeral nature of hard bottom in the 

region. 

 Although sand shoals are subject to currents, waves, and tidal forces, they are considered 

relatively permanent seafloor features. Most shoals were formed during Pleistocene low sea 

level periods when the continental shelf was exposed. Shoals could be continually altered or 

completed removed as a result of dredging projects and are unlikely to reform as they were 
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Table 7-1. Invertebrate and fish species for which Essential Fish Habitat (EFH) has been 

identified in the vicinity of the four sand resource areas offshore North Carolina. 

Species are listed in phylogenetic order.

Species Life Stage EFH Document 

Invertebrates 

Ocean quahog (Arctica islandica) Adults, juveniles MAFMC, 1998a 

Atlantic surfclam (Spisula solidissima) Adults, juveniles MAFMC, 1998a 

Long-finned squid (Loligo pealei) Adults, juveniles MAFMC, 1998b 

Short-finned squid (Illex illecebrosus) Adults, juveniles MAFMC, 1998b 

Fishes 

Spiny dogfish (Squalus acanthias) Adults, juveniles MAFMC, 1999 

Dusky shark (Carcharhinus obscurus) Late juveniles/subadults, 

neonates/early juveniles NMFS, 1999 

Sandbar shark (Carcharhinus plumbeus) Adults, late juveniles/subadults, 

neonates/early juveniles, NMFS, 1999 

Tiger shark (Gaelocerdo cuvieri) Adults, late juveniles/subadults, 

neonates/early juveniles NMFS, 1999 

Sand tiger shark (Carcharius taurus) Adults, neonates/early juveniles NMFS, 1999 

Atlantic sharpnose shark (Rhizoprionodon 

terraenovae) Adults NMFS, 1999 

Atlantic sturgeon (Acipenser oxyrhynchus) Adults, juveniles ASMFC, 1998 

Atlantic herring (Clupea harengus) Adults ASMFC, 1999 

Red hake (Urophycis chuss) Juveniles, larvae, eggs NEFMC, 1998 

Monkfish (Lophius americanus) Larvae, eggs NEFMC, 1998 

Black sea bass (Centropristis striata) Adults, juveniles, larvae MAFMC, 1998c 

Bluefish (Pomatomus saltatrix) Adults, juveniles, larvae, eggs MAFMC, 1998d 

Cobia (Rachycentron canadum) Adults SAFMC, 1998 

Scup (Stenotomus chrysops) Adults, juveniles MAFMC, 1998c 

Red drum (Sciaenops ocellatus) Adults SAFMC, 1998 

King mackerel (Scomberomorus cavalla) Adults SAFMC, 1998 

Spanish mackerel (Scomberomorus maculatus) Adults SAFMC, 1998 

Atlantic mackerel (Scomber scombrus) Adults, juveniles, larvae, eggs MAFMC, 1998b 

Butterfish (Peprilus triacanthus) Adults, juveniles, larvae, eggs MAFMC, 1998b 

Windowpane flounder (Scophthalmus aquosus) Juveniles NEFMC, 1998 

Summer flounder (Paralichthys dentatus) Adults, juveniles, larvae, eggs MAFMC, 1998c 

ASMFC = Atlantic States Marine Fisheries Commission. 

MAFMC = Mid-Atlantic Fishery Management Council. 

NEFMC = New England Fishery Management Council. 

NMFS = National Marine Fisheries Service. 

SAFMC = South Atlantic Fishery Management Council. 
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originally if changes are drastic. The extent to which partial or complete shoal removal affects 

fish populations is uncertain. Some have speculated that fishes use shoals for feeding, staging, 

or orientation areas during short-term or long-term migrations. Although no specific scientific 

information exists supporting these assertions, the potential for impacts cannot be discounted 

(Research Planning, Inc. et al., 2001). 

 The area encompassed by the four sand resource areas is very small relative to the 

mapped EFH characteristics. For this reason, the effect of dredging on EFH for the managed 

species is expected to be minimal. 

7.6.4 Sea Turtles 

7.6.4.1 Entrainment 

 The main potential effect of dredging on sea turtles is physical injury or death caused by 

entrainment. Numerous sea turtle injuries and mortalities have been documented during 

dredging projects along Florida’s east coast (Studt, 1987; Dickerson et al., 1992; Slay, 1995). 

Several turtles have been taken during dredging operations in the Mid-Atlantic states in recent 

years (NMFS, 1996). However, dredging has not been implicated as a major cause of death or 

injury to sea turtles in the region (NMFS, 1996). 

 Of the five turtle species that may occur off North Carolina, three (loggerhead, Kemp’s 

ridley, and green) are considered to be at risk from dredging activities because of their benthic 

feeding habits (Dickerson et al., 1992). Loggerheads are the most abundant turtles in the 

project area, and historically, they have been the species most frequently entrained during 

hopper dredging, possibly accounting for up to 86% of the total (Reine and Clarke, 1998). 

Kemp’s ridley and green turtles historically have accounted for much smaller portions of the 

total. Leatherbacks, which also occur in North Carolina waters, are unlikely to be affected by 

dredging because they feed in the water column rather than on the bottom (NMFS, 1996). 

Hawksbills are unlikely to be affected because they are the least common turtles in the area and 

occur only as occasional vagrants. 

 Physical impact can occur when a turtle feeding or resting on the seafloor is contacted by 

the dredge head. Two types of dredges may be used on the proposed project. Cutterhead 

suction dredges are considered unlikely to kill or injure turtles, perhaps because the cutterhead 

encounters a smaller area of seafloor per unit time, allowing more opportunity for turtles to 

escape (Palermo, 1990). Hopper dredges are believed to pose the greatest risk to sea turtles 

(Dickerson, 1990; NMFS, 1997). There has been considerable research into designing modified 

hopper dredges with turtle deflectors that reduce the likelihood of entraining sea turtles (Studt, 

1987; Berry, 1990; Dickerson et al., 1992; Banks and Alexander, 1994; USACE, 1999). If a 

hopper dredge is used on this project during the loggerhead turtle nesting season of April 

through September, the NMFS may require turtle monitoring and use of a turtle-deflecting 

draghead. 

 Chelonid sea turtles (i.e., those other than leatherbacks) feed primarily in depths of 15 m 

or less (NMFS, 1996). The risk of physical impacts to turtles would appear to be greatest in the 

shallowest water depths in each potential borrow site. However, there is also risk in deeper 

water because when turtles feed there, they tend to stay on the bottom longer (NMFS, 1996). 

7.6.4.2 Habitat Modification 

 Juvenile and subadult loggerheads, Kemp’s ridleys, and greens use northeastern coastal 

waters as developmental habitat, foraging on benthic organisms (see Section 2.3.2.4). 
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Therefore, when borrow sites have significant concentrations of benthic resources, dredging can 

reduce food availability both by removing potential food items and altering the benthic habitat 

(NMFS, 1996). Effects would be temporary, as benthic populations would be expected to 

recover over a period of months to years (see Section 7.5.3). In addition, borrow sites represent 

only a small portion of the shallow benthic habitat available off North Carolina. Trawl sampling 

in support of this document showed that potential food for turtles (e.g., various benthic 

crustaceans, mollusks, and echinoderms) was present in the borrow sites (see Section 6.0). 

7.6.4.3 Turbidity and Anoxia 

 Sea turtles in and near the project area may encounter turbid water that could temporarily 

interfere with feeding. However, due to the limited aerial extent and transient occurrence of the 

sediment plume, turbidity is considered unlikely to significantly affect turtle behavior or survival. 

 Measurements around cutterhead dredging operations show that elevated levels of 

suspended sediments are restricted to the immediate vicinity of the cutterhead with little turbidity 

reaching surface waters (LaSalle et al., 1991). Maximum suspended sediment concentrations 

typically occur within 3 m above the cutterhead and decline exponentially to the sea surface. 

Suspended sediment concentrations in near-bottom waters may be elevated up to several 

hundred meters laterally from the cutterhead location. 

 Hopper dredging operations also produce turbidity as the dragheads are pulled through 

bottom sediments. However, the main source of turbidity during hopper dredging operations is 

sediment release during hopper overflow (LaSalle et al., 1991). A plume may occasionally be 

visible at distances of 1,200 m or more. 

 In addition to turbidity, dredging may produce localized hypoxia/anoxia in the water 

column due to oxygen consumption of the suspended sediments (LaSalle et al., 1991). In 

general, oxygen levels in the plume and near-bottom waters may approach zero, but levels in 

adjacent waters outside the plume are at or near normal. Due to the limited extent and transient 

occurrence of hypoxia/anoxia, no significant effects on turtles are expected. 

7.6.4.4 Noise 

 Dredging is one of many human activities in the marine environment that produce 

underwater noise. Sea turtles have limited hearing ability (Ridgway et al., 1969; Lenhardt, 

1994), and its role in their life cycle and behavior is poorly known. It is believed that sea turtles 

do not rely on sound to any significant degree for communication or food location, although it 

has been suggested that low-frequency sound may be involved in natal beach homing behavior 

(Dodd, 1988). The latter could be a consideration during the nesting season. 

 There are indications that underwater noise is unlikely to significantly affect turtles. First, 

studies in the Gulf of Mexico have shown some evidence for positive association of sea turtles 

with petroleum platforms (Rosman et al., 1987; Lohoefener et al., 1990) despite the industrial 

noise associated with these sites. Second, experiments testing the use of seismic airguns to 

repel turtles from dredging activities indicate that even loud noises cause avoidance only at very 

close range (e.g., 100 m or less) (Moein et al., 1994; Zawila, 1994). If noise does have any 

impact on turtles, it would most likely be positive by encouraging avoidance of the dredge. 

7.6.4.5 Project Scheduling Considerations 

 Project scheduling is one way to avoid or minimize turtle impacts during dredging (Studt, 

1987; Arnold, 1992). If a hopper dredge is used, then it would be best to avoid the loggerhead 

nesting and hatching season, which has been reported as May 1 through November 15 of any 
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year (USFWS as cited in USACE, 2000). This same period would generally have higher risk of 

encountering juvenile and subadult Kemp’s ridley and green turtles. However, the vagaries of 

winter weather off North Carolina may make it difficult to prohibit dredging during these months. 

If use of a hopper dredge during this season cannot be avoided, then other mitigation and 

monitoring requirements are likely to be imposed, such as turtle monitoring and use of a turtledeflecting draghead (NMFS, 1996). If a cutterhead suction dredge is used, seasonal or other 

restrictions are considered unnecessary because there is little likelihood of killing or injuring sea 

turtles. 

7.6.5 Marine Mammals 

7.6.5.1 Physical Injury 

 Marine mammals are unlikely to be physically injured by dredging per se because they 

generally do not rest on the bottom and most can avoid contact with dredging vessels and 

equipment. The odontocete marine mammals most likely to be found in nearshore waters off 

North Carolina, such as bottlenose dolphin and Atlantic spotted dolphin, are agile swimmers that 

are presumed capable of avoiding physical injury during dredging. 

 However, physical injury from vessel strikes is a serious concern for three endangered 

species of mysticetes: North Atlantic right whale, fin whale, and humpback whale. Recovery 

plans for these species identify vessel strikes as a contributing factor impeding their recovery 

(NMFS, 1991a,b; Reeves et al., 1998). Vessel strikes are an especially serious concern for 

North Atlantic right whales. NMFS published regulations in February 1997 restricting vessel 

approaches of North Atlantic right whales. These regulations prohibit all approaches within 

460 m of any North Atlantic right whale, whether by boat, aircraft, or other means (NMFS, 

1998). Measures to minimize the potential for vessel strikes of endangered whales could be 

part of any Biological Opinion issued by the NMFS for dredging off North Carolina. 

 The harbor porpoise, which is a candidate for listing as a threatened species, is unlikely to 

be injured by dredging vessels or equipment. The major threat to the recovery of this species is 

gillnetting (NMFS, 1998). The NMFS has indicated that interactions of this species with 

dredging are unlikely (U.S. Environmental Protection Agency, 1997). 

7.6.5.2 Turbidity 

 Marine mammals in and near the project area may encounter turbid water during 

dredging. This turbidity could temporarily interfere with feeding or other activities, but the 

animals could easily swim to avoid turbid areas. Due to the limited areal extent and transient 

occurrence of the sediment plume, turbidity is considered unlikely to significantly affect marine 

mammal behavior or survival. 

7.6.5.3 Noise 

 Dredging can be a significant source of continuous underwater noise in nearshore areas, 

particularly in low frequencies (<1,000 Hz) (Richardson et al., 1995). This noise typically 

diminishes to background levels within about 20 to 25 km of the source (Richardson et al., 

1995). Noise levels are not sufficient to cause hearing loss or other auditory damage to marine 

mammals (Richardson et al., 1995). However, some observations in the vicinity of dredging 

operations and other industrial activities have documented avoidance behavior, while in other 

cases, animals seem to develop a tolerance for the industrial noise (Malme et al., 1983; 

Richardson et al., 1995). Due to the frequency range of their hearing, mysticetes (baleen 

whales) are more likely to be affected by low-frequency noise than are odontocetes. The main 
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concern would be that dredging noise could cause avoidance of the project area during 

humpback whale and (especially) North Atlantic right whale migrations. 

7.6.5.4 Project Scheduling Considerations 

 Common shelf species such as bottlenose dolphin and Atlantic spotted dolphin may be 

present year-round and, as noted above, are unlikely to be adversely affected by dredging. 

Harbor porpoise occurrence is more seasonal (primarily spring and fall), but the likelihood of 

impact is so low that it does not warrant seasonal restrictions on dredging. 

 Fin whales would be most likely to occur during winter, whereas humpback and North 

Atlantic right whales could occur as transients during spring and fall. There is no “resident” 

population of these whales in the study region; rather, they would be temporary inhabitants, or 

would be transiting the area during seasonal migrations. Generally, the probability of 

encountering these species in the project area would be lowest during summer. The months of 

March and April would be least favorable because North Atlantic right whales are expected to 

migrate northward in shallow waters along the North Carolina coast during this period (Lee and 

Socci, 1989; MMS, 1990). Whether or not seasonal restrictions on dredging are implemented, 

measures to minimize possible vessel interactions with endangered whales are likely to be 

required by NMFS. 

7.7 POTENTIAL CUMULATIVE EFFECTS 

 Cumulative physical environmental impacts from multiple sand extraction scenarios at one 

or all sand borrow sites within the study area were evaluated to assess long-term effects at 

potential borrow sites and along the coastline. Results presented above for wave and sediment 

transport processes reflect the impact of large extraction scenarios from one or multiple offshore 

sites that are expected to be within the cumulative sand resource needs of the State for the next 

10 years. It was determined that no significant changes to longshore sediment transport will 

result from the modeled borrow site configurations, where borrow Sites 3 west and 3 east were 

modeled separately. If these sites were dredged simultaneously, the potential impacts were 

estimated to exceed the significance criterion and may require mitigation along the affected 

shoreline, or a redesign of the borrow site configuration. Overall, the cumulative impacts of 

sand mining offshore North Carolina on wave propagation and sediment transport processes 

are expected to be negligible under the conditions imposed. 

 Cumulative impacts resulting from multiple sand mining operations within a sand resource 

area are a concern when evaluating potential long-term effects on benthic and pelagic 

assemblages. The most likely mechanism that could result in adverse cumulative effects is the 

extraction of sand from the same shoal site more than once, resulting in a relatively deep pit 

feature where development of natural benthic assemblages is impeded. For the purpose of this 

analysis, it is assumed that a different area of the targeted sand shoal, or a different shoal, 

would be dredged each replenishment interval. Given that the expected beach replenishment 

interval is on the order of 5 to 10 years, and that the expected recovery time of the affected 

benthic community after sand removal is anticipated to be much less than that (within 2 years), 

the potential for significant cumulative benthic impacts is remote. No cumulative impacts to the 

pelagic environment, including zooplankton, squids, fishes, sea turtles, and marine mammals, 

are expected from multiple sand mining operations within a sand resource area. 
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8.0 CONCLUSIONS 

 The primary purpose of this study was to address environmental concerns associated with 

potential sand dredging from the OCS offshore Dare County, NC for beach replenishment. 

Primary concerns focused on physical and biological components of the environment at four 

proposed sand resource areas. Biological and physical processes data were analyzed to 

assess potential impacts of offshore dredging activities within the study area to minimize or 

preclude long-term adverse environmental impacts at potential borrow sites and along the 

coastline landward of these sites. Furthermore, wave transformation and sediment transport 

numerical modeling were used to simulate physical environmental effects of proposed sand 

dredging operations to ensure that offshore sand resources are developed in an 

environmentally responsible manner. Of the four potential sand resource areas, five borrow 

sites were chosen for evaluating sand extraction scenarios based on historical beach 

replenishment needs and resource information from the NCGS and MMS. 

 The following summary documents results and conclusions regarding potential 

environmental effects of sand mining on the OCS for replenishing sand to eroding beaches. 

Because benthic and pelagic biological characteristics are in part determined by spatially 

varying physical processes throughout the study area, physical processes analyses are 

summarized first. 

8.1 WAVE TRANSFORMATION MODELING 

 Excavation of an offshore borrow site can alter incoming wave heights and the direction of 

wave propagation. Offshore topographic relief causes waves to refract toward the shallow 

edges of borrow sites. Changes in the wave field caused by borrow site geometry may change 

local sediment transport rates, where some areas may experience a reduction in longshore 

transport and other areas may show an increase. The most effective means of quantifying 

physical environmental effects of sand dredging from shoals on the continental shelf is by 

applying wave transformation numerical modeling tools that recognize the random nature of 

incident waves as they propagate onshore. To determine the potential physical impacts 

associated with dredging at borrow sites located offshore Dare County, NC, spectral wave 

transformation modeling (STWAVE) was performed for existing and post-dredging bathymetric 

conditions. Comparison of computations for existing and post-dredging conditions illustrated the 

relative impact of borrow site excavation on wave-induced coastal processes. Although the 

interpretation of wave modeling results is relatively straightforward, evaluating the significance 

of predicted changes for accepting or rejecting a borrow site is more complicated. 

 As part of any offshore sand mining effort, the MMS requires evaluation of potential 

environmental impacts associated with alterations to nearshore wave patterns. To determine 

potential impacts associated with borrow site excavation, the influence of borrow site geometry 

on local wave refraction patterns was evaluated. Because large natural spatial and temporal 

variability exists within the wave climate at a particular site, determination of physical impacts 

associated with sand mining must consider the influence of process variability. A method based 

on historical wave climate variability, as well as local wave climate changes directly attributable 

to borrow site excavation, was applied to determine appropriate criteria for assessing impact 

significance. 

 From existing conditions model results, bottom topography offshore Bodie Island modifies 

waves as they propagate shoreward. For example, the shoal in the vicinity of Borrow Site 1 

refracts the wave field, causing a slight focusing of wave energy behind the feature. Wave 

heights behind the shoal are about 0.4 m greater than wave heights at the northern and 
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southern limits of the shoal (see Figure 4-9). Because energy is conserved, focusing of wave 

energy behind the shoal causes a reduction of energy at the northern and southern margins of 

the shoal, which is apparent by the reduced wave heights in these areas. 

 In addition to the effects of offshore bottom features, waves were refracted by the straight 

and parallel bottom contours in the nearshore. As with changes in wave direction, wave heights 

also were modified by nearshore bathymetry. Waves begin to shoal (increase in height) about 

500 m offshore, and increase in height by 0.2 m before breaking begins. Wave heights are 

reduced as energy dissipates in the surf zone, which is about 60 m wide for waves approaching 

from the southeast. 

 Output from post-dredging model runs indicate that wave heights within borrow sites are 

reduced relative to existing conditions, and this effect was more pronounced in cases that had 

greater wave heights. Wave fields landward of proposed borrow sites are modified by 

refraction. As waves propagate across a borrow site (deeper water than the surrounding area), 

wave refraction guides waves away from the center of the excavation site and toward the 

shallow edges. The net effect is to create a shadow zone of reduced wave energy immediately 

landward of a borrow site and a zone of increased wave energy updrift and downdrift of the 

borrow site. In the immediate vicinity of Site 2, for example, wave heights increased by a 

maximum of 0.05 m at the northern and southern edges of the borrow site and decreased by a 

maximum of 0.06 m behind the borrow site. 

 Because spectral wave model results were used, and because different frequencies in the 

spectrum were refracted to varying degrees at the borrow sites, regions of increased and 

reduced wave energy gradually diffuse as the wave field approaches shore. As such, borrow 

sites farther offshore affect a greater length of shoreline, however the actual magnitude of the 

impact was reduced because the affected wave field had a greater distance to diffuse (see 

Figure 4-11). This was evident from comparing the effect of Sites 1 and 2. Borrow Site 1 is the 

larger of the two, but farther offshore, and therefore the wave height change from existing to 

post-dredging conditions at the shoreline was less than changes caused by Site 2. 

 During storm conditions (Case 8), where wave period was significantly larger than normal 

wave characteristics, waves were more affected by offshore bathymetric gradients. Although 

the direction of wave propagation was not modified as much as was indicated under normal 

conditions, wave heights changed significantly (e.g., a maximum height of 2.4 m at the southern 

side of Oregon Inlet) relative to offshore conditions. At offshore shoals directly east of the inlet, 

wave heights increase approximately 0.7 m over the offshore boundary condition. Several 

shoal areas along the modeled coastline show similar impacts on wave heights. 

 The area of maximum increased wave heights for post-dredging conditions was located at 

the northernmost corner of Site 1, where wave heights increased 0.09 m over existing 

conditions. The area of maximum wave height decrease was located at the landward corner of 

Site 1, where wave heights were reduced by 0.12 m from existing conditions. Model output for 

storm wave conditions indicates that the length of affected shoreline where borrow site shadows 

propagate extends approximately 40 km to the north, starting from about 3 km north of Oregon 

Inlet. Overall, wave transformation affected by potential borrow site geometry was minimal 

during normal and storm conditions.

8.2 CIRCULATION AND SEDIMENT TRANSPORT DYNAMICS 

Current measurements and analyses and wave transformation modeling provided 

baseline information on incident processes impacting coastal environments under existing 

conditions and with respect to proposed sand mining activities for beach replenishment. 
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Ultimately, the most important data set for understanding physical processes impacts from 

offshore sand extraction is changes in sediment transport dynamics resulting from potential 

sand extraction scenarios relative to existing conditions. 

 While no large-scale predictive circulation models were developed to quantify effects of 

dredging at sand borrow sites, the analysis of current patterns resulting from this study suggests 

proposed sand mining will have negligible impact on large-scale shelf circulation. The proposed 

sand mining locations are small relative to the entire shelf area, and it is anticipated that 

proposed dredging will not remove enough material to significantly alter major bathymetric 

features in the region. Therefore, the forces and geometric features that principally affect 

circulation patterns will remain relatively unchanged. 

 Three independent sediment transport analyses were completed to evaluate physical 

environmental impacts due to sand mining. First, historical sediment transport trends were 

quantified to document regional, long-term sediment movement throughout the study area using 

historical bathymetric data sets. Erosion and accretion patterns were documented, and 

sediment transport rates in the littoral zone and at offshore borrow sites were evaluated to 

assess potential changes due to offshore sand dredging activities. Second, sediment transport 

patterns at proposed offshore borrow sites were evaluated using wave modeling results and 

current measurements. Post-dredging wave model results were integrated with regional current 

measurements to estimate sediment transport trends for predicting borrow site infilling rates. 

Third, sediment transport was predicted using wave modeling output to estimate potential 

impacts to the longshore sand transport system (beach erosion and accretion). All three 

methods were compared for documenting consistency of measurements relative to predictions, 

and potential physical environmental impacts were identified. 

8.2.1 Historical Sediment Transport Patterns 

 Regional geomorphic changes between 1862/70 to 1970/96 were analyzed for assessing 

long-term, net coastal sediment transport dynamics. Although these data did not provide 

information on potential impacts of sand dredging from proposed borrow sites, they did provide 

a means of verifying predictive sediment transport models relative to infilling rates at borrow 

sites and longshore sand transport. 

 Shoreline position and nearshore bathymetry change documented four important trends 

relative to study objectives. First, the predominant direction of sediment transport on the 

continental shelf and along southern Bodie Island was north to south. Second, the most 

dynamic features within the study area were the beaches and shoals associated with Oregon 

Inlet. Third, alternating bands of erosion and accretion on the continental shelf east of the 

Federal-State boundary illustrated relatively slow but steady reworking of the upper shelf 

surface as sand ridges migrated from north to south. The process by which this was occurring 

at all sand resource areas suggested that borrow sites in these regions would fill with sand 

transported from the adjacent seafloor at rates ranging from 20,000 to 70,000 m3

/yr. Fourth, net 

longshore transport rates determined from seafloor changes in the littoral zone between Kitty 

Hawk and Oregon Inlet indicated increasing transport rates north and south of a point about 10 

km north of the inlet. Net longshore transport near Nags Head was about 160,000 m3

/yr to the 

north, increasing to about 335,000 m3

/yr near Kitty Hawk. These rates are very consistent with 

those determined from wave modeling and sediment transport predictions. 
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8.2.2 Sediment Transport at Potential Borrow Sites 

 In addition to predicted modifications to the wave field, potential sand mining at offshore 

borrow sites resulted in minor changes in sediment transport pathways in and around the 

dredged regions. Modifications to bathymetry caused by sand mining only influenced local 

hydrodynamic and sediment transport processes in the offshore area. Although wave heights 

changed at the dredged borrow sites, areas adjacent to the sites did not undergo dramatic 

changes in wave or sediment transport characteristics. 

 Initially, it is anticipated that sediment transport at borrow sites will occur rapidly after sand 

dredging is completed. For water depths at the proposed borrow sites, minimal impacts to 

waves and regional sediment transport are expected during infilling. The characteristics of 

sediment that replaces dredged material during infilling will vary based on location, time of 

dredging, and storm characteristics following dredging episodes. Average transport rates 

ranged from a minimum of about 38,000 m3

/yr (Sites 3 east and 4) to a high of about 

123,000 m3

/yr (Site 2), while the infilling time varies between 37 to 98 years. Site 2 had the 

greatest infilling rate due to its shallow water depth relative to the other sites and its large 

perimeter. Because Site 2 is in shallow water, wave-induced currents and background currents 

were larger than at deeper surrounding sites, and more sediment was mobile in the proximity of 

the borrow site. Furthermore, sites that have a larger surface area generally will trap more 

sediment in a given time period. The range of infilling times was based of the volume of sand 

numerically dredged from a borrow site, as well as the sediment transport rate. Infilling times 

would have been reduced if storm events were incorporated in the analysis. 

8.2.3 Nearshore Sediment Transport Modeling 

 Comparisons of average annual sediment transport potential were performed for existing 

and post-dredging conditions to indicate the relative impact of dredging to longshore sediment 

transport processes. Sediment transport potential is a useful indicator of shoreline impacts 

caused by offshore borrow sites because the computations include the borrow site influence on 

wave height and direction. Net and gross transport potential were computed using existing 

wave conditions and post-dredging conditions for two alternate borrow site configurations: 

1) Sites 1, 2, 3 east, and 4 modeled together, and 2) Sites 1, 2, 3 west, and 4 modeled together. 

Analysis of gross and net transport potential indicated that there was a reversal of the direction 

of transport along southern Bodie Island. North of this spot, net transport was to the north, while 

south of this point to Oregon Inlet, net transport was strongly to the south. Computed north- and 

south-directed transport potential showed that transport was strongly bi-directional, with a gross 

transport magnitude of approximately 600,000 m3

/yr far north of Oregon Inlet and a net transport 

magnitude of only 250,000 m3

/yr. Closer to the inlet, littoral drift became more unidirectional 

and to the south, with gross and net transport potential magnitudes peaking at over 

600,000 m3

/yr. 

 Difference in longshore transport potential between existing conditions and the two borrow 

site configurations resulted in a maximum negative change (post-dredging minus existing 

condition) in computed net sediment transport potential for the second configuration (Sites 1, 2, 

3 west, and 4), where peak change was -34,000 m3

/yr, or 45% of the net transport potential at 

this point. The maximum positive change was approximately 14,000 m3

/yr or only 8% of the net 

transport potential computed at this point. The final determination of dredging significance was 

made by comparing actual change in transport potential between existing and post-dredging 

conditions to a significance envelope of one-half the standard deviation (±0.5σ) along the 

shoreline (Kelley et al., 2001). It was determined that no significant changes to longshore 

sediment transport would result from the modeled borrow site configurations, where Sites 3 
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west and 3 east were modeled separately. For sites dredged simultaneously, the impacts were 

estimated to exceed the ±0.5σ, and therefore would require mitigation along the affected 

shoreline or a redesign of the borrow site configuration, likely a reduction in maximum design 

depth at one of the sites. 

8.3 BENTHIC ENVIRONMENT 

 Results of field surveys for biological characterization agree well with previous 

descriptions concerning benthic assemblages associated with shallow shelf habitats offshore 

North Carolina. Benthic assemblages surveyed from the sand resource areas consisted of 

members of the major invertebrate and vertebrate groups commonly found in the general area. 

Numerically dominant infaunal groups included numerous crustaceans, echinoderms, mollusks, 

and polychaetes, while epifaunal taxa consisted primarily of decapods, sea stars, and squid. 

Canonical correlation analysis indicated that the composition of benthic assemblages inhabiting 

North Carolina sand resource area stations was affected primarily by survey, and secondarily by 

sediment type. Temporal variability in infaunal assemblage composition also was evidenced by 

both qualitative and quantitative community measures. Only 34% of the infaunal taxa sampled 

over the entire project was collected during both the May and September surveys. Most (59%) 

of the remainder of censused taxa were collected only during the September cruise, resulting in 

higher mean species richness values compared to the May survey. Also, infaunal abundance 

was greater during the September survey (2,967/m2

) than during May (994/m2). 

 Biological surveys of the sand resource areas support the findings of numerous other 

investigations in the region that have found strong associations of infaunal taxa with particular 

sedimentary habitats. This infauna-habitat relationship was apparent in the results of the 

surveys, despite relatively limited sampling in the study region. Canonical correlation analysis 

indicated that, after survey, the composition of benthic assemblages inhabiting sand resource 

area stations mostly was affected by relative percentages of gravel and sand. Infaunal 

assemblage distributions reflected sediment type distributions. Apparent changes in surficial 

sediment composition between May and September probably accounted for some of the 

between-survey differences in infaunal assemblage composition. 

 Numerically dominant fishes collected during the 1998 sand resource area surveys are 

typical components of demersal assemblages in the study region. Fishes such as clearnose 

skate (Raja eglanteria), flounder (Paralichthys sp.), scup (Stenotomus chrysops), and searobin 

(Prionotus scitulus) were numerical dominants during the surveys and these species 

consistently are among the most ubiquitous and abundant demersal taxa in the region. Despite 

inherent spatial and temporal heterogeneity in the distribution and abundance of demersal 

fishes and low numbers in trawls, results of the 1998 surveys of the sand resource areas 

generally are consistent with results of historical demersal survey results in the region. 

 Potential benthic effects from dredging will result from sediment removal, 

suspension/dispersion, and deposition. Effects on infaunal populations will occur primarily 

through removal of individuals along with sediments. Effects are expected to be short-term and 

localized. Seasonality and recruitment patterns indicate that removal of sand between late fall 

and early spring would result in less stress on benthic populations. Early-stage succession will 

begin within days of sand removal, through larval recruitment dominated by opportunistic taxa, 

especially polychaetes and bivalves such as Solemya velum and Tellina agilis. These species 

are adapted to environmental stress and exploit suitable habitat when it becomes available. 

Later successional stages of benthic recolonization will be more gradual, involving taxa that 

generally are less opportunistic and longer lived. Immigration of motile annelids, crustaceans, 

and echinoderms into impacted areas also will begin soon after excavation. 
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 While community composition may differ for a period of time after the last dredging, the 

infaunal assemblage type that exists in mined areas will be similar to naturally occurring 

assemblages in the study region, particularly those assemblages inhabiting inter-ridge troughs. 

Based on previous observations of infaunal reestablishment, and assuming that dredged sites 

do not create a sink for very fine sediments or result in hypoxic or anoxic conditions, the infaunal 

community in dredged sites most likely will become reestablished within 2 years, and will exhibit 

levels of infaunal abundance, diversity, and composition comparable to nearby non-dredged 

areas. Given that the expected beach replenishment interval is on the order of a decade, and 

that the expected recovery time of the affected benthic community after sand removal is 

anticipated to be much less than that, the potential for significant cumulative benthic impacts is 

remote. 

8.4 PELAGIC ENVIRONMENT 

 Zooplankters could be affected by entrainment and turbidity. Considering the high 

reproductive capacity of zooplankton along with the relatively small area of the dredge suction 

field and the volume of water entrained compared to the overall volume of surrounding waters, it 

is unlikely that entrainment or turbidity would greatly affect zooplankton populations or 

assemblages in the North Carolina sand resource areas. If borrow sites are used in Area 3, an 

environmental window excluding summer and fall months could be considered to avoid dredging 

when fish juveniles and larvae are most prevalent, but only if additional data become available 

to determine the extent of impacts and justify the restriction.

Squids could be entrained if they encountered the suction field of a hydraulic dredge. In 

addition, squid eggs that are laid in large clusters on the seafloor could be removed with 

sediments. Dredging is unlikely to significantly impact squid populations in the vicinity of the 

sand resource areas. This precludes the need for an environmental window or specific project 

scheduling to protect squid resources. 

 Dredging should not present a significant problem for pelagic fishes offshore North 

Carolina. Potential effects to fishes could occur through entrainment, attraction, and turbidity. If 

an environmental window is sought to protect pelagic fishes from dredging impacts, the spring 

to fall period would encompass the peak seasons for the economically important species. 

Quantitative data are lacking to support the use of an environmental window to lessen effects on 

pelagic fishes. 

 EFH for several fish species (and life stages) overlap the four sand resource areas 

offshore North Carolina. The region encompassed by the four sand resource areas is very 

small relative to the mapped EFH characteristics. For this reason, the effect of dredging on 

EFH for the managed species is expected to be minimal. 

 The main potential effect of dredging on sea turtles is physical injury or death caused by 

the suction and/or cutting action of the dredge head. No significant effects on turtles are 

expected from turbidity, anoxia, or noise. Three sea turtle species that typically occur off North 

Carolina (loggerhead, Kemp's ridley, and green) are considered to be at risk because of their 

benthic feeding habits. Loggerheads are the most abundant turtles in the project area, and 

historically, they have been the species most frequently entrained during hopper dredging. If a 

hopper dredge is used, then it would be best to avoid the loggerhead nesting season from April 

through September. This same period would generally have higher risk of encountering juvenile 

and subadult Kemp’s ridley and green turtles. However, the vagaries of winter weather off North 

Carolina make it infeasible to prohibit dredging during these months. If use of a hopper dredge 

during this season cannot be avoided, then other mitigation and monitoring requirements may 

be appropriate, such as turtle monitoring and use of a turtle-deflecting draghead. If a cutterhead 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

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suction dredge is used, seasonal or other restrictions are considered unnecessary because 

there is little likelihood of killing or injuring sea turtles. 

 Marine mammal species occurring commonly on the shelf, such as bottlenose dolphin and 

Atlantic spotted dolphin, may be present year-round but are unlikely to be adversely affected by 

dredging due to their agility. Harbor porpoise occurrence is more seasonal (primarily spring and 

fall), but the likelihood of impact is so low that it does not warrant seasonal restrictions on 

dredging. Fin whales would be most likely to occur during winter, whereas humpback and North 

Atlantic right whales could occur as transients during spring and fall. There is no “resident” 

population of these whales in the study region; rather, they would be temporary inhabitants, or 

would be transiting the area during seasonal migrations. Generally, the probability of 

encountering these species in the project area would be lowest during summer. The months of 

March and April would be least favorable because North Atlantic right whales are expected to 

migrate northward in shallow waters along the North Carolina coast during this period. Whether 

or not seasonal restrictions on dredging are implemented, measures to minimize possible 

vessel interactions with endangered whales are likely to be required by the NMFS. 

8.5 SYNTHESIS 

 The data collected, analyses performed, and simulations conducted for this study indicate 

that proposed sand dredging at sites evaluated on the OCS offshore North Carolina should 

have minimal environmental impact on fluid and sediment dynamics and biological communities. 

Short-term impacts to benthic communities are expected due to the physical removal of borrow 

material, but the potential for significant cumulative benthic impacts is remote. Additionally, no 

cumulative effects to any of the pelagic groups are expected from potential sand mining 

operations. 

 Minimal physical environmental impacts due to potential sand dredging operations (two 

primary dredging configurations) have been identified through wave and sediment transport 

simulations. The significance of changes to longshore transport along the modeled shoreline 

resulting from dredging proposed borrow sites to their maximum design depths was determined 

by comparing actual change in transport potential between existing and post-dredging 

conditions to a significance envelope of one-half the standard deviation (±0.5σ) along the 

shoreline. Under representative wave conditions for each of the model grids offshore Dare 

County, North Carolina, it was determined that no significant changes in longshore sediment 

transport potential would result from modeled borrow site configurations, where Sites 3 west 

and 3 east were modeled separately. For sites dredged simultaneously, the impacts were 

estimated to exceed the ±0.5σ, and therefore would require mitigation along the affected 

shoreline or a redesign of the borrow site configuration, likely a reduction in maximum design 

depth at one of the sites. Because minor impacts to wave and sediment transport dynamics 

and biology may occur under conditions similar to those imposed in the present study, additional 

data collection and analysis may be required for a specific sand extraction scenario to 

determine the extent of impacts. 
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9.0 LITERATURE CITED 

Able, K.W. and M.P. Fahay, 1998. The First Year in the Life of Estuarine Fishes in the Middle 

Atlantic Bight. Rutgers University Press, New Brunswick, NJ, 343 pp. 

Ackerman, B.B., 1995. Aerial surveys of Manatees: a summary and progress report, pp. 13-33. 

In: T.J. O’Shea, B.B. Ackerman, and H.F. Percival (editors), Population Biology of the 

Florida Manatee. National Biological Service Information and Technical Report No. 1, 

289 pp. 

Adams, K.T., 1942. Hydrographic Manual. U.S. Department of Commerce, Coast and Geodetic 

Survey, Special Publication 143, 940 pp. 

Anders, F.J. and M.R. Byrnes, 1991. Accuracy of shoreline change rates as determined from 

maps and aerial photographs. Shore and Beach, 59(1): 17-26. 

Applied Biology, Inc., 1979. Biological Studies Concerning Dredging and Beach Nourishment at 

Duval County, Florida with a Review of Pertinent Literature. U.S. Army Corps of 

Engineers, Jacksonville District, Jacksonville, FL. 

Arnold, D.W., 1992. The scientific rationale for restricting coastal construction activities during 

the marine turtle nesting season. In: L.S. Tait (compiler), New Directions in Beach 

Management. Proceedings of the 5th Annual National Conference on Beach Preservation 

Technology, St. Petersburg, FL, pp. 374-380. 

Atlantic States Marine Fisheries Commission, 1998. Atlantic Sturgeon Stock Assessment Peer 

Review Report. Atlantic States Marine Fisheries Commission, Washington, D.C., 125 pp. 

Atlantic States Marine Fisheries Commission, 1999. Amendment 1 to the Interstate Fishery 

Management Plan for Atlantic Herring. Atlantic States Marine Fisheries Commission, 

Washington, D.C. 

Aubrey, D.G. and K.O. Emery, 1983. Eigenanalysis of recent United States sea levels. 

Continental Shelf Research, 2(1): 21-33. 

Auld, A.H. and J.R. Schubel, 1978. Effects of suspended sediment on fish eggs and larvae: a 

laboratory assessment. Estuarine and Coastal Marine Science, 6: 153-164. 

Banks, G.E. and M.P. Alexander, 1994. Development and Evaluation of a Sea Turtle-Deflecting 

Hopper Dredge Draghead. U.S. Army Engineer Waterways Experiment Station, 

Vicksburg, MS, Miscellaneous Paper HL-94-5. 

Barry A. Vittor & Associates, Inc., 1985. Tuscaloosa Trend Regional Data Search and 

Synthesis Study, Synthesis Report, Volume I. U.S. Department of the Interior, Minerals 

Management Service, New Orleans, LA, OCS Study MMS 85-0056. 

Barry A. Vittor & Associates, Inc., 1999. Pre- and Post-Dredging Monitoring of 

Macroinvertebrate Assemblages at a Borrow Area Located Offshore of Coney Island, New 

York: 1992-1998 Data Synthesis. Prepared for the U.S. Army Corps of Engineers, New 

York District, 10 pp. + app. 

Barry, M., 1978. Behavioral Response of Yellowfin Tuna, Thunnus albacares, and Kawakawa, 

Euthynnus affinis, to Turbidity. U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, Environmental Research Laboratories, Pacific Marine 

Environmental Laboratory, Seattle, WA. Deep Ocean Mining Environmental Study 

(DOMES), Unpublished Manuscript Number 31. National Technical Information Service 

No. PB-297, 106 pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

234

Battjes, J.A. and J.P. Janssen, 1978. Energy loss and set-up due to breaking of random waves. 

Proc. 23rd Int. Conf. Coastal Engineering, ASCE, pp. 569-587. 

Beardsley, R.C. and W.C. Boicourt, 1981. On estuarine and continental shelf circulation in the 

Middle Atlantic Bight. In: B.A. Warren and C. Wunsch (editors), Evolution of Physical 

Oceanography, The MIT Press, pp.198-233. 

Beardsley, R.C. and B. Butman, 1974. Circulation on the New England continental shelf: 

response to strong winter storms. Geophysical Research Letters, 1: 181-184. 

Benfield, M.C. and T.J. Minello, 1996. Relative effects of turbidity and light intensity on reactive 

distance and feeding of an estuarine fish. Environmental Biology of Fishes, 46: 211-216. 

Berger, T.J., P. Hamilton, R.J. Wayland, O.J. Blanton, W.C. Boicourt, J.H. Churchill, and D.R. 

Watts, 1995. A Physical Oceanographic Field Program Offshore North Carolina. U.S. 

Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, 

New Orleans, 345 pp. 

Berry, S.A., 1990. Canaveral Harbor entrance channel operational measures to protect sea 

turtles. In: D.D. Dickerson and D.A. Nelson (compilers), Proceedings of the National 

Workshop on Methods to Minimize Dredging Impacts on Sea Turtles, Jacksonville, 

Florida. U.S. Army Engineer Waterways Experiment Station, Environmental Effects 

Laboratory, Vicksburg, MS, Miscellaneous Paper EL-90-5, pp. 49-52. 

Bigelow, H.B, 1922. Exploration of the coastal waters off the northeastern United States in 1916 

by the U.S. Fisheries Schooner Grampus. Bulletin of the Museum of Comparative 

Zoology, 65: 88-188. 

Biggs, R.B., 1968. Environmental effects of overboard spoil disposal. Journal of Sanitary 

Engineering Division, Proceeding Paper 5979, 94(SA3): 477-478. 

Birkemeier, W.A., A.W. DeWall, C.S. Gorbics, and H.C. Miller, 1981. A User’s Guide to the 

CERC Field Research Facility. U.S. Army Corp of Engineers, Waterways Experiment 

Station, Coastal Engineering Research Center, Miscellaneous Report 81-7. 

Blake, N.J., L.J. Doyle, and J.J. Culter, 1995. Impacts and Direct Effects of Sand Dredging for 

Beach Renourishment on the Benthic Organisms and Geology of the West Florida Shelf. 

U.S. Department of the Interior, Minerals Management Service, Office of International 

Activities and Marine Minerals, Herndon, VA. Executive Summary, OCS Report MMS 

95-0004, 23 pp. Final Report, OCS Report MMS 95-0005, 109 pp. Appendices, OCS 

Report MMS 95-0005. 

Blaxter, J.H.S., 1968. Visual thresholds and spectral sensitivity of herring larvae. Journal of 

Experimental Biology, 48: 39-53. 

Blaylock, R.A., J.W. Hain, L.J. Hansen, D.L. Palka, and G.T. Waring, 1995. U.S. Atlantic and 

Gulf of Mexico Marine Mammal Stock Assessments. NOAA Tech. Mem. NMFS-SEFSC363, 211 pp. 

Boehlert, G.W. and J.B. Morgan, 1985. Turbidity enhances feeding abilities of larval Pacific 

herring, Clupea harengus pallasi. Hydrobiologia,123: 161-170. 

Boesch, D.F., 1972. Species diversity of marine macrobenthos in the Virginia area. 

Chesapeake Science, 13(3): 206-211. 

Boesch, D.F., 1973. Classification and community structure of macrobenthos in the Hampton 

Roads area, Virginia. Marine Biology, 21: 226-244. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

235

Boicourt, W.C., 1973. The Circulation of Water on the Continental Shelf from Chesapeake Bay 

to Cape Hatteras. Ph.D. Thesis, Johns Hopkins University, 147 pp. 

Bonsdorff, E., 1983. Recovery potential of macrozoobenthos from dredging in shallow brackish 

waters. In: L. Cabioch et al. (editors), Fluctuations and Succession in Marine 

Ecosystems, Proceedings of the 17th European Symposium on Marine Biology, 

Oceanologica Acta, pp. 27-32. 

Boss, S.K. and C.W. Hoffman, 2001. Geologic Framework Derived from High-Resolution 

Seismic Reflection, Side-Scan Sonar, and Vibracore Data Offshore Oregon Inlet to Duck, 

Dare County, North Carolina. Contract Report to the U.S. Minerals Management Service, 

International Activities and Marine Minerals Division, Cooperative Agreement 14-12-0001-

30348. 

Boss, S.K., C.W. Hoffman, and S.R. Riggs, 1999. Interpretation of Side-Scan Sonar Records of 

a Portion of the Inner North Carolina Continental Shelf Between Oregon Inlet and Kitty 

Hawk. Contract Report to the U.S. Minerals Management Service, International Activities 

and Marine Minerals Division, Cooperative Agreement 14-12-0001-30348, 19 p. 

Boss, S.K., C.W. Hoffman, and B. Cooper, 2002. Influence of fluvial processes on the 

Quaternary geologic framework of the continental shelf, North Carolina, USA. Marine 

Geology, 183: 45-65. 

Bowen, P.R. and G.A. Marsh, 1988. Benthic Faunal Colonization of an Offshore Borrow Pit in 

Southeastern Florida. U.S. Army Engineer Waterways Experiment Station, Vicksburg, 

MS, Miscellaneous Paper D-88-5. 

Breitburg, D.L., 1988. Effects of turbidity on prey consumption by striped bass larvae. 

Transactions of the American Fisheries Society, 117: 72-77. 

Brodziak, J. and L. Hendrickson, 1999. An analysis of environmental effects on survey catches 

of squids Loligo pealei and Illex illecebrosus in the northwest Atlantic. Fishery Bulletin, 

97: 9-24. 

Brodziak, J.K.T. and W.K. Macy III, 1996. Growth of longfinned squid, Loligo pealei, in the 

northwest Atlantic. Fishery Bulletin, 94: 212-236. 

Brown, C.B., 1950. Sediment Transportation. In: H. Rouse (editor), Engineering Hydraulics, 

John Wiley and Sons, NY, 1,039 pp. 

Bruton, M.N., 1985. The effects of suspensoids on fish. Hydrobiologia, 125: 221-241. 

Bumpus, D.F., 1973. A description of the circulation on the continental shelf of the east coast of 

the United States. Progress in Oceanography, 6: 111-157. 

Burke, V.J., S.J. Morreale, P. Logan, and E.A. Standora, 1992. Diet of Green Turtles (Chelonia 

mydas) in the waters of Long Island, New York. In: M. Salmon and J. Wyneken (editors), 

Proceedings of the Eleventh Annual Workshop on Sea Turtle Biology and Conservation, 

NOAA Tech. Memo. NMFS-SEFC-302, pp. 140-142. 

Burke, V.J., E.A. Standora, and S.J. Morreale, 1993. Diet of juvenile Kemp's Ridley and 

Loggerhead sea turtles from Long Island, New York. Copeia, 1993: 1,176-1,180. 

Burlas, M., G.L. Ray, and D. Clarke, 2001. The New York District’s Biological Monitoring 

Program for the Atlantic Coast of New Jersey, Asbury Park to Manasquan Section Beach 

Erosion Control Project, Final Report. U.S. Army Corps of Engineers, New York District, 

Engineer Research and Development Center, Waterways Experiment Station. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

236

Bush, K. and S.L. Kupferman, 1980. Wind stress direction and the alongshore pressure gradient 

in the Middle Atlantic Bight. Journal of Physical Oceanography, 10: 469-471. 

Butman, B., M. Noble, and D.A. Folger, 1979. Long-term observations of bottom currents and 

bottom sediment movement on the Mid-Atlantic Continental Shelf. Journal of Geophysical 

Research, 84: 1187-1205. 

Byles, R.A., 1988. Satellite Telemetry of Kemp's Ridley Sea Turtle, Lepidochelys kempii, in the 

Gulf of Mexico. Report to the National Fish and Wildlife Foundation, 40 pp. 

Byrnes, M.R. and C.G. Groat, 1991. Characterization of the Development Potential of Ship 

Shoal Sand for Beach Replenishment of Isles Dernieres. Final Report, U.S. Department 

of the Interior, Minerals Management Service, Office of International Activities and Marine 

Minerals, Herndon, VA, 164 pp. 

Byrnes, M.R. and M.W. Hiland, 1994. Compilation and analysis of shoreline and bathymetry 

data (Appendix B). In: N.C. Kraus, L.T. Gorman, and J. Pope (editors), Kings Bay Coastal 

and Estuarine Monitoring and Evaluation Program: Coastal Studies. Technical Report 

CERC-94-09, U.S. Army Engineer Waterways Experiment Station, Coastal Engineering 

Research Center, Vicksburg, MS, pp. B1-B89. 

Cadrin, S.X., 1998. Longfin inshore squid. In: S.H. Clark (editor), Status of Fishery Resources 

off the Northeastern United States for 1998. U.S. Department of Commerce, NOAA Tech 

Mem. NMFS-NE-115, pp. 118-119. 

Carr, A., 1987. New perspectives on the pelagic stage of sea turtle development. Conservation 

Biology, 1: 103-121. 

Centre for Cold Ocean Resources Engineering (C-CORE), 1995. Proposed Marine Mining 

Technologies and Mitigation Techniques: A Detailed Analysis With Respect to the Mining 

of Specific Offshore Mineral Commodities. Contract report for U.S. Department of the 

Interior, Minerals Management Service, OCS Report MMS 95-0003, C-CORE Publication 

96-C15, 280 pp. + appendices. 

Cerame-Vivas, M.J. and I.E. Gray, 1966. The distribution pattern of benthic invertebrates of the 

continental shelf off North Carolina. Ecology, 47: 260-270. 

Chang, S., F.W. Steimle, Jr., R.N. Reid, S.A. Fromm, V.S. Zdanowicz, and R.A. Pikanowski, 

1992. Association of benthic macrofauna with habitat types and quality in the New York 

Bight. Marine Ecology Progress Series, 89: 237-251. 

Chuang, W.S., D.P. Wang, and W.C. Boicourt, 1979, Low-frequency current variability on the 

southern Mid-Atlantic Bight. Journal of Physical Oceanography, 9: 1,144-1,154. 

Cleary, W.J. and T.P. Marden, 1999. Shifting shorelines: a pictorial atlas of North Carolina's 

Inlets. NC Sea Grant Special Publication #UNC-SG-99-04. North Carolina Sea Grant, 

NC State University, Raleigh, NC. 51 p. 

Coastal Oceanographics, 1996. Hypack Navigation Software Version 6.4. 

Coastline Surveys Limited, 1998. Marine Aggregate Mining Benthic and Surface Plume Study. 

Final report to the U.S. Department of the Interior, Minerals Management Service and 

Plume Research Group, Report 98/555/03, 168 pp. 

Colvocoresses, J.A. and J.A. Musick, 1984. Species associations and community composition 

of the Middle Atlantic Bight continental shelf demersal fishes. Fishery Bulletin, 82(4): 295-

314. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

237

Cook, T.M., 2000. Surface Current Variability on the North Carolina Shelf Observed with High 

Frequency Radar. MS Thesis, University of Miami, Miami, FL, 97 pp. 

Cook, T.M. and Shay, L.K., 2002. Surface M2 tidal currents along the North Carolina shelf 

observed with high-frequency radar. Journal of Geophysical Research, 107(C12), 3222. 

Cowen, R.K., J.A. Hare, and M.P. Fahay, 1993. Beyond hydrography: can physical processes 

explain larval fish assemblages within the Middle Atlantic Bight? Bulletin of Marine 

Science, 53(2): 567-587. 

Crouse, D.T., 1988. Sea turtle strandings: a new perspective on North Carolina Biology. In: 

B.A. Schroeder (compiler), Proceedings of the Eighth Annual Workshop on Sea Turtle 

Biology and Conservation. NOAA Tech. Mem. NMFS-SEFC-214, pp. 13-16. 

Crowell, M., S.P. Leatherman, and M.K. Buckley, 1991. Historical shoreline change: error 

analysis and mapping accuracy. Journal of Coastal Research, 7(3): 839-852. 

Cruickshank, M.J., J.P. Flanagan, B. Holt, and J.W. Padan, 1987. Marine Mining on the Outer 

Continental Shelf: Environmental Effects Overview. U.S. Department of the Interior, 

Minerals Management Service, OCS Report 87-0035, 66 pp. 

Cudaback, C.N. and J.L. Largier, 2001. The cross-shelf structure of wind- and buoyancy-driven 

circulation over the North Carolina inner shelf. Continental Shelf Research, 21: 1,649-

1,668. 

Davis, H.C. and H. Hidu, 1969. Effects of turbidity-producing substances in sea water on eggs 

and larvae of three genera of bivalve mollusks. Veliger, 11(4): 316-323. 

Day, J.H., J.G. Field, and M.P. Montgomery, 1971. The use of numerical methods to determine 

the distribution of the benthic fauna across the continental shelf of North Carolina. Journal 

of Animal Ecology, 40: 93-125. 

Dickerson, D.D., 1990. Workgroup 1 Summary. In: D.D. Dickerson and D.A. Nelson 

(compilers), Proceedings of the National Workshop on Methods to Minimize Dredging 

Impacts on Sea Turtles. U.S. Army Engineer Waterways Experiment Station, Vicksburg, 

MS, Miscellaneous Paper EL-90-5, 89 pp. 

Dickerson, D.D., D.A. Nelson, M. Wolff, and L. Manners, 1992. Summary of dredging impacts 

on sea turtles: Kings Bay, Georgia and Cape Canaveral, Florida. In: M. Salmon and J. 

Wyneken (compilers), Proceedings of the Eleventh Annual Workshop on Sea Turtle 

Biology and Conservation, Jekyll Island, GA. NOAA Tech. Mem. NMFS-SEFSC-302, 

pp. 148-151. 

Dickerson, D.D., K.J. Reine, and D.G. Clarke, 1998. Economic Impacts of Environmental 

Windows Associated with Dredging Operations. U.S. Army Engineer Research and 

Development Center, Vicksburg, MS, DOER Tech. Note TN DOER-E3. 

Dodd, C.K., Jr., 1988. Synopsis of the Biological Data on the Loggerhead Sea Turtle Caretta 

caretta (Linnaeus 1758). U.S. Fish and Wildlife Service Biological Report 88(4), 110 pp. 

Dolan, R., 1987. The Ash Wednesday Storm of 1962: 25 Years Later. Journal of Coastal 

Research, 3(2): ii-vi. 

Dolan R. and H. Lins, 1986. The Outer Banks of North Carolina. U.S. Geological Survey 

Professional Paper 1177-B, 43 pp. 

Dolan, R. and J.J. Smith, 2003. The stabilization of Oregon Inlet, North Carolina. Shore and 

Beach, 71(3): 7-9. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

238

Dolan, R., B. Hayden, C. Rea, J. Heywood, 1979. Shoreline erosion rates along the middle 

Atlantic coast of the United States. Geology, 7: 602-606. 

Donovan, G.P., 1991. A review of IWC stock boundaries. International Whaling Commission, 

Special Issue 13, pp. 39-68. 

Doyle, M.J., W.W. Morse, and A.W. Kendall, Jr., 1993. A comparison of larval fish assemblages 

in the temperate zone of the northeast Pacific and northwest Atlantic oceans. Bulletin of 

Marine Science, 53(2): 588-644. 

Duffield, D.A., 1986. Investigations of Genetic Variability in Stocks of Bottlenose Dolphins 

(Tursiops truncatus). Final report to the National Marine Fisheries Service, Southeast 

Fisheries Commission. Contract No. NA83-GA-00036, 53 pp. 

Duffield, D.A., S.H. Ridgway, and L.H. Cornell, 1983. Hematology distinguishes coastal and 

offshore forms of dolphins (Tursiops). Canadian Journal of Zoology, 61: 930-933. 

Eckert, K.L., 1995. Leatherback Sea Turtle, Dermochelys coriacea. In: P.T. Plotkin (editor), 

National Marine Fisheries Service and U. S. Fish and Wildlife Service Status Reviews for 

Sea Turtles Listed Under the Endangered Species Act of 1973, Silver Spring, MD. 

Eckert, S.A., D.W. Nellis, K.L. Eckert, and G.L. Kooyman, 1986. Diving patterns of two 

leatherback sea turtles (Dermochelys coriacea) during internesting intervals at Sandy 

Point, St. Croix, U.S. Virgin Islands. Herpetologica, 42(3): 381-388. 

Ellis, M.Y., 1978. Coastal Mapping Handbook. U.S. Department of the Interior, Geological 

Survey, U.S. Department of Commerce, National Ocean Service, U.S. Government 

Printing Office, Washington, D.C., 199 pp. 

Everts, C.H., J.P. Battley, Jr., P.N. Gibson, 1983. Shoreline movements Report 1, Cape Henry, 

Virginia to Cape Hatteras, North Carolina, 1849-1980. U.S. Army Corps of Engineers, 

Coastal Engineering Research Center, Technical Report CERC-83-1, 111 pp. + 18 maps. 

Fauchald, K. and P. Jumars, 1979. The diet of worms: a study of polychaete feeding guilds. 

Oceanography and Marine Biology Annual Review, 17: 193-284. 

Fischer, W. (editor), 1978. FAO Species Identification Sheets for Fishery Purposes, Western 

Central Atlantic (Fishing Area 31), Volume VI. 

Frazier, N.B., 1995. Loggerhead sea turtle, Caretta caretta. In: P.T. Plotkin (editor), National 

Marine Fisheries Service and U. S. Fish and Wildlife Service Status Reviews for Sea 

Turtles Listed under the Endangered Species Act of 1973. Silver Spring, MD. 

Fredette, T.J., W.F. Bohlen, D.C. Rhoads, and R.W. Morton, 1988. Erosion and resuspension 

effects of Hurricane Gloria at Long Island Sound dredged material disposal sites. In: 

Proceedings of the Water Quality ‘88 Seminar, Charleston, South Carolina. U.S. Army 

Corps of Engineers, Hydraulic Engineering Center, Davis, CA. 

Gabriel, W., 1992. Persistence of demersal fish assemblages between Cape Hatteras and 

Nova Scotia, Northwest Atlantic. Journal Northwest Atlantic Fisheries Science, 14: 29-46. 

Gardiner, S.L., 1976. Errant polychaete annelids from North Carolina. Journal of the Elisha 

Mitchell Scientific Society, 91: 77-220. 

Gaskin, D.E, 1992. The status of the harbour porpoise. Canadian Field-Naturalist, 106: 36-54. 

Germano, J.D., 1983. Infaunal Succession in Long Island Sound: Animal-Sediment Interactions 

and the Effects of Predation. Ph.D. dissertation, Yale University, New Haven, CT, 206 pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

239

Germano, J.D. and D.C. Rhoads, 1984. REMOTS sediment profiling at the Field Verification 

Program (FVP) disposal site. In: Dredging ‘84 Proceedings, American Society of Civil 

Engineers, Clearwater, FL, pp. 536-544. 

Gilbert, R.O., 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand 

Reinhold, New York, NY, 320 pp. 

Glenn, S.M. and C.C. Ebbesmeyer, 1994. The structure and propogation of a Gulf Stream 

frontal eddy along the North Carolina shelf break. Journal of Geophysical Research 

99(C3): 5029-5046. 

Goda, Y., 1985. Random Seas and Design of Maritime Structures. University of Tokyo Press, 

Tokyo, Japan. 

Goldberg, W.M., 1989. Biological effects of beach nourishment in South Florida: the good, the 

bad, and the ugly. Proceedings of Beach Preservation Technology, 1988, Shore and 

Beach Preservation Association, Tallahassee, FL. 

Grant, G.C., 1988. Seasonal occurrence and dominance of Centropages congeners in the 

Middle Atlantic Bight, USA. Hydrobiologia, 167/168: 227-237. 

Grant, G.C., 1991. Chaetognatha from the central and southern Middle Atlantic Bight: species 

composition, temperature salinity relationships, and inter-specific associations. Fishery 

Bulletin, 89(1): 33-40. 

Grant, W.D. and Madsen, O.S., 1986. The continental shelf bottom boundary layer. Annual 

Review Fluid Mechanics, 18: 265-305. 

Grassle, J.F. and J.P. Grassle, 1974. Opportunistic life histories and genetic systems in marine 

benthic polychaetes. Journal of Marine Research, 32: 253-284. 

Gray, J.S., 1974. Animal-sediment relationships. Oceanography and Marine Biology Annual 

Review, 12: 223-261. 

Grober, L.E., 1992. The Ecological Effects of Beach Replenishment. M.S. Thesis, Duke 

University, School of the Environment, NC, 109 pp. 

Grosslein, M.D., 1976. Some results of fish surveys in the mid-Atlantic: important for assessing 

environmental impacts. In: G. Gross (editor), Middle Atlantic Continental Shelf and the 

New York Bight, Proceedings of the Symposium, American Museum of Natural History, 

New York City, 1975, American Society of Limnology and Oceanography, Inc., Allen 

Press, Inc., Lawrence, KS, pp. 312-328. 

Grosz, A.E., C.W. Hoffman, P.E. Gallagher, Reid, J.C., and J.C. Hathaway, 1990. Heavymineral resource potential of surficial sediments on the Atlantic Continental shelf offshore 

of North Carolina: a reconnaissance study. Open-File Report 90-245, Unpublished report 

prepared for North Carolina Geological Survey, 58 pp. 

Grothues, T.M. and R.K. Cowen, 1999. Larval fish assemblages and water mass history in a 

major faunal transition zone. Continental Shelf Research, 19: 1,171-1,198. 

Guza, R.T., 1992. Infragravity waves, Part 2: Shelf-wide variability. EOS, Transactions of the 

American Geophysical Union, 73 (43/supp.): 246. 

Hall, S.J., 1994. Physical disturbance and marine benthic communities: life in unconsolidated 

sediments. Oceanography and Marine Biology Annual Review, 32: 179-239. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

240

Hammer, R.M., 1981. Day-night differences in the emergence of demersal zooplankton from a 

sand substrate in a kelp forest. Marine Biology, 62: 275-280. 

Hammer, R.M. and R.C. Zimmerman, 1979. Species of demersal zooplankton inhabiting a kelp 

forest ecosystem off Santa Catalina Island, California. Bulletin of Southern California 

Academy of Sciences, 78(3): 199-206. 

Hammer, R.M., B.J. Balcom, M.J. Cruickshank, and C.L. Morgan, 1993. Synthesis and Analysis 

of Existing Information Regarding Environmental Effects of Marine Mining. Final report by 

Continental Shelf Associates, Inc. for the U.S. Department of the Interior, Minerals 

Management Service, Office of International Activities and Marine Minerals, Herndon, VA, 

OCS Study MMS 93-0006, 392 pp. 

Hendrickson, L., 1998. Northern Shortfin Squid. In: S.H. Clark (editor), Status of Fishery 

Resources Off the Northeastern United States for 1998. U.S. Department of Commerce, 

NOAA Tech Mem. NMFS-NE-115, pp. 116-117. 

Herbich, J.B., 1992. Handbook of Dredging Engineering. McGraw-Hill, Inc., New York, NY, 

740 pp. 

Herbich, J.B. and S.B. Brahme, 1991. Literature Review and Technical Evaluation of Sediment 

Resuspension During Dredging. U.S. Army Engineer Waterways Experiment Station, 

Vicksburg, MS., Contract Report HL-91-1. 

Hine, A.C., S.W. Snyder, and A.C. Neumann, 1979. Coastal plain and inner shelf structure, and 

geological history: Bogue Banks area, North Carolina. Prepared for the North Carolina 

Science and Technology Committee. 

Hirota, J., 1981. Potential effects of deep-sea minerals mining on macrozooplankton in the 

north equatorial Pacific. Marine Mining, 3(1/2): 19-57. 

Hoelzel, A.R., C.W. Potter, and P.B. Best, 1998. Genetic differentation between parapatric 

‘nearshore’ and ‘offshore’ populations of the bottlenose dolphin. Proceedings of the Royal 

Society of London, 265: 1,177-1,183. 

Hoffman, C.W., 1998. Preliminary assessment of potential sand resource areas offshore of 

Nags Head, Kitty Hawk, and Kill Devil Hills, North Carolina. U.S. Mineral Management 

Service/State of North Carolina Sand Resource Task Force, Unpublished Report, 12 p. 

Horn, D.R., M. Ewing, B.M. Horn, and M.N. Delach, 1971. Turbidities of the Hatteras and Sohm 

abyssal plains, western North Atlantic. Marine Geology, 11: 287-323. 

Houston, J.R., 1995. Beach nourishment. Shore and Beach, 63(1): 21-24. 

Houston, J.R., 2002. The economic value of beaches – a 2002 update. Shore and Beach, 70(1): 

9-12. 

Hrabovsky, L., 1990. Hydraulic cutterhead pipeline dredging. In: D.D. Dickerson and D.A. 

Nelson (compilers), Proceedings of the National Workshop on Methods to Minimize 

Dredging Impacts on Sea Turtles, Jacksonville, FL. U.S. Army Engineer Waterways 

Experiment Station, Vicksburg, MS, Miscellaneous Paper EL-90-5, pp. 56-58. 

Hu, V.J.H., 1981. Ingestion of deep-sea mining discharge by five species of tropical copepods. 

Water, Air, and Soil Pollution, 15: 433-440. 

Hunt, D.E., D.J.P. Swift and H. Palmer, 1977. Constructional shelf topography, Diamond 

Shoals, North Carolina. Geological Society of America Bulletin, 88: 299-311. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

241

Ingle, R.M., 1952. Studies on the Effect of Dredging Operations Upon Fish and Shellfish. 

Florida State Board of Conservation, Technical Series 5, 26 pp. 

Inman D.L. and R. Dolan, 1989. The Outer Banks of North Carolina: budget of sediment and 

inlet dynamics along a migrating barrier system. Journal of Coastal Research, 5(2): 

193-237. 

Jefferson, T.A., S. Leatherwood, and M.A. Webber, 1993. FAO Species Identification Guide. 

Marine Mammals of the World. Rome, FAO, 320 pp. 

Jensen, R.E., 1983. Methodology for the Calculation of a Shallow-Water Wave Climate. WIS 

Report 8, U.S. Army Engineering Waterways Experiment Station, Vicksburg, MS. 

Johnson, R.O. and W.G. Nelson, 1985. Biological effects of dredging in an offshore borrow 

area. Florida Scientist, 48: 166-188. 

Johnston, D.D. and D.J. Wildish, 1982. Effect of suspended sediment on feeding by larval 

herring (Clupea harengus harengus L.). Bulletin of Environmental Contamination and 

Toxicology, 29: 61-67. 

Jokiel, P.L., 1989. Effects of marine mining dredge spoils on eggs and larvae of a commercially 

important species of fish, the Mahimahi (Coryphaena hippurus). Marine Minerals, 8: 305-

315. 

Jones, G. And S. Candy, 1981. Effects of dredging on the macrobenthic infauna of Botany Bay. 

Australian Journal of Marine and Freshwater Research, 32: 379-399. 

Kamphuis, J.W., 1990. Alongshore sediment transport rate. Proc. 22nd Coastal Engineering 

Conference, Delft, Netherlands. 

Kane, J., 1997. Persistent spatial and temporal abundance patterns for late-stage copepodites 

of Centropages hamatus (Copepoda: Calanoida) in the U.S. northeast continental shelf 

ecosystem. Fishery Bulletin, 95 (1): 85-98. 

Keinath, J.A., J.A. Musick, and D.E. Barnard, 1996. Abundance and Distribution of Sea Turtles 

off North Carolina. U.S. Department of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA, OCS Study MMS 95-0024, 156 pp. 

Kelley, S.W., J.S. Ramsey, M.R. Byrnes, 2001. Numerical Modeling Evaluation of the 

Cumulative Physical Effects of Offshore Sand Dredging for Beach Nourishment. U.S. 

Department of the Interior, Minerals Management Service, International Activities and 

Marine Minerals Division (INTERMAR), Herndon, VA. OCS Report MMS 2001-098, 

95 pp. + 106 pp. appendices. 

Kenney, R.D., 1990. Bottlenose dolphins off the northeastern United States. In: S. Leatherwood 

and R.R. Reeves (editors), The Bottlenose Dolphin. Academic Press, San Diego, CA, 

pp. 369-386. 

Kerr, S.J., 1995. Silt, Turbidity, and Suspended Sediments in the Aquatic Environment: An 

Annotated Bibliography and Literature Review. Ontario Ministry of Natural Resources, 

Southern Region Science and Technology Transfer Unit, Technical Report TR-008, 277 

pp. 

Kirk, K.L., 1992. Effects of suspended clay on Daphnia body growth and fitness. Freshwater 

Biology, 28: 102-109. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

242

Kocik, J., 1998a. River Herring. In: S.H. Clark (editor), Status of Fishery Resources off the 

Northeastern United States for 1998. U.S. Department of Commerce, NOAA Tech Mem. 

NMFS-NE-115, pp. 134-135. 

Kocik, J., 1998b. American Shad. In: S.H. Clark (editor), Status of Fishery Resources off the 

Northeastern United States for 1998. U.S. Department of Commerce, NOAA Tech Mem. 

NMFS-NE-115, pp. 136-137. 

Kraus, S.D., A.R. Knowlton, and J.H. Prescott, 1988. Surveys for Wintering Right Whales 

(Eubalaena glacialis) Along the Southeastern United States, 1984-1988. Final report to 

the Department of the Interior, Minerals Management Service, Branch of Environmental 

Studies, Washington, DC, 19 pp. + app. 

Kraus, S.D., R.D. Kenney, A.R. Knowlton, and J.N. Ciano, 1993. Endangered Right Whales of 

the Southwestern North Atlantic. Final report to the Department of the Interior, Minerals 

Management Service, Atlantic OCS Region, Herndon, VA, 69 pp. 

Kropp, R.K., 1995. Brigantine Inlet to Great Egg Harbor Inlet, Atlantic County, New Jersey: 

Benthic Animal Assessment of Potential Borrow Source. Report prepared for the U.S. 

Army Corps of Engineers, Philadelphia District, Philadelphia, PA, Contract No. DAAL03-

91-C-0034. 

Laney, R.W., D.J. Newcomb, and C.S. Manooch, 1999. Appendix B: Impact assessment of 

proposed Corps of Engineers dredging associated with the Dare County beaches project 

upon fisheries. In: H. Hall (editor). Northern Dare County Storm Damage Reduction 

Project, Dare County, North Carolina. U.S. Fish and Wildlife Service, Division of 

Ecological Services, Raleigh, NC. Draft Fish and Wildlife Coordination Act Report. 

Lange, A.M.T. and M.P. Sissenwine, 1980. Biological considerations relevant to the 

management of squid (Loligo pealei and Illex illecebrosus) of the northwest Atlantic. 

Marine Fishery Review, 42(7-8): 23-38. 

Langfelder, L.J., D.B. Stafford, and M. Amein, 1970. Coastal erosion in North Carolina. Journal 

of Waterways and Harbors Division, Proceedings American Society of Civil Engineers, 

96(WW2): 531-545. 

Larson, K.W. and C.E. Moehl, 1988. Entrainment of anadromous fish by hopper dredge at the 

mouth of the Columbia River. In: C.A. Simenstad (editor), Effects of Dredging on 

Anadromous Pacific Coast Fishes, Workshop Proceedings, University of Washington Sea 

Grant, pp. 102-112. 

Larson, M. and N.C. Kraus, 1994. Temporal and spatial scales of beach change, Duck, North 

Carolina. Marine Geology, 117: 75-94. 

Larson, M. and N.C. Kraus, 1995. Prediction of cross-shore sediment transport at different 

spatial and temporal scales. In: J.H. List and J.H.J. Terwindt (editors), Large-Scale 

Coastal Behavior, Marine Geology Special Issue, 126(1/4): 111-128. 

LaSalle, M.W., D.G. Clarke, J. Homziak, J.D. Lunz, and T.J. Fredette, 1991. A Framework for 

Assessing the Need for Seasonal Restrictions on Dredging and Disposal Operations. 

U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, Technical 

Report D-91-1, 74 pp. 

Lee, D.S. and W.M. Palmer, 1981. Records of the leatherback turtle, Dermochelys coriacea 

(Linnaeus), and other marine turtles in North Carolina waters. Brimleyana, 5: 95-106. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

243

Lee, D.S. and M. Socci, 1989. Potential Impact of Oil Spills on Seabirds and Selected Other 

Oceanic Vertebrates off the North Carolina Coast. Prepared by the North Carolina State 

Museum of Natural Sciences for the State of North Carolina, Department of 

Administration, Raleigh, NC, 85 pp. 

Leffler, M.W., C.F. Baron, B.L. Scarborough, K.K. Hathaway, and R.T. Hayes, 1992. Annual 

Data Summary for 1990 CERC Field Research Facility, Volume I. U.S. Army Corp of 

Engineers, CERC-92-3, 69 pp. 

Lenhardt, M.L., 1994. Seismic and very low frequency sound induced behaviors in captive 

Loggerhead marine turtles (Caretta caretta). In: K.A. Bjorndal, A.B. Bolten, D.A. Johnson, 

and P.J. Eliazar (compilers), Proceedings of the Fourteenth Annual Symposium on Sea 

Turtle Biology and Conservation, Hilton Head, SC, U.S. Department of Commerce, 

National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 

Southeast Fisheries Science Center, Miami, FL. 

Lentz, S.L., R.T. Guza, S. Elgar, F. Feddersen, and T.H.C. Herbers, 1999. Momentum 

balances on the North Carolina inner shelf. Journal of Geophysical Research, 104(C8): 

18,205-18,226. 

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers, 1990. Association of Sea 

Turtles with Petroleum Platforms in the North-central Gulf of Mexico. U.S. Department of 

the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, 

LA, OCS Study MMS 90-0025, 90 pp. 

Loosanoff, V.L., 1962. Effects of turbidity on some larval and adult bivalves. Proceedings of the 

14th Annual Session, Gulf and Caribbean Fisheries Institute, pp. 80-95. 

Lutcavage, M. and J.A. Musick, 1985. Aspects of the biology of sea turtles in Virginia. Copeia, 

1985(2): 449-456. 

MacArthur, R.H., 1960. On the relative abundance of species. American Naturalist, 94: 25-36. 

MacArthur, R.H. and E.O. Wilson, 1967. Theory of Island Biogeography. Princeton University 

Press, Princeton, NJ, 203 pp. 

Madsen, O.S., 1987. Mechanics of Sediment Transport in the Wave-Dominated Environment. 

ASCE Short Course Notes, Coastal Sediments ’87, New Orleans, LA, 94 p. 

Madsen, O.S., L.D. Wright, J.D. Boon and T.A. Chisholm, 1993. Wind Stress, bed roughness, 

and sediment suspension on the inner shelf during an extreme storm event. Continental 

Shelf Research, 13 (11): 1303-1324. 

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird, 1983. Investigations of the 

Potential Effects of Underwater Noise from Petroleum Industry Activities on Migrating 

Gray Whale Behavior. Report by Bolt, Beranek and Newman, Inc., Cambridge, MA, for 

the U.S. Department of the Interior, Minerals Management Service, Anchorage, AK, BBN 

Rep. 5366. 

Manooch, C.S. and D. Raver, 1984. Fisherman's Guide, Fishes of the Southeastern United 

States. North Carolina State Museum of Natural History, Raleigh, NC. 

Marine Turtle Expert Working Group, 1996a. Status of the Loggerhead Turtle Population 

(Caretta caretta) in the Western North Atlantic. 50 pp. 

Marine Turtle Expert Working Group, 1996b. Kemp’s Ridley Sea Turtle (Lepidochelys kempii) 

Status Report. 49 pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

244

Marquez, R.M., 1990. Sea Turtles of the World. FAO Species Catalogue, Volume 11. FAO, 

Rome, 81 pp. 

Marsh, G.A. and D.B. Turbeville, 1981. The environmental impact of beach nourishment: two 

studies in southeastern Florida. Shore and Beach, 49(3): 40-44. 

Maurer, D., R.T. Keck, J.C. Tinsman, W.A. Leathem, C. Wethe, C. Lord, and T.M. Church, 

1986. Vertical migration and mortality of marine benthos in dredged material: a synthesis. 

Internationale Revue der gesamten Hydrobiologie, 71: 49-63. 

McBride, R.A. and Moslow, T.F., 1991. Origin, evolution, and distribution of shoreface sand 

ridges, Atlantic inner shelf, U.S.A. Marine Geology, 97: 57-85. 

McCaully, J.E., R.A. Parr, and D.R. Hancock, 1977. Benthic infauna and maintenance 

dredging: a case study. Water Research, 11: 233-242. 

McGraw, K.A. and D.A. Armstrong, 1988. Fish entrainment by dredges in Grays Harbor, 

Washington. In: C.A. Simenstad (editor), Effects of Dredging on Anadromous Pacific 

Coast Fishes, Workshop Proceedings, University of Washington Sea Grant, pp. 113-131. 

McNulty, J.K., R.C. Work, and H.B. Moore, 1962. Some relationships between the infauna of 

the level bottom and the sediment in South Florida. Bulletin of Marine Science in the Gulf 

and Caribbean, 12: 322-332. 

Mead, J.G. and C.W. Potter, 1995. Recognizing two populations of the Bottlenose Dolphin 

(Tursiops truncatus) off the Atlantic coast of North America: morphologic and ecologic 

considerations. International Biological Research Institute Reports 5: 31-43. 

Meylan, A., 1992. Hawksbill turtle Eretmochelys imbricata. In: P. Moler (editor), Rare and 

Endangered Biota of Florida. University Press of Florida, Gainesville, FL, pp. 95-99. 

Mid-Atlantic Fishery Management Council, 1998a. Amendment 12 to the Atlantic Surfclam and 

Ocean Quahog Fishery Management Plan. Mid-Atlantic Fishery Management Council, 

Dover, DE, 249 pp. 

Mid-Atlantic Fishery Management Council, 1998b. Amendment 8 to the Atlantic Mackerel, 

Squid, and Butterfish Fishery Management Plan. Mid-Atlantic Fishery Management 

Council, Dover, DE, 351 pp. + apps. 

Mid-Atlantic Fishery Management Council, 1998c. Amendment 12 to the Summer Flounder, 

Scup, and Black Sea Bass Fishery Management Plan. Mid-Atlantic Fishery Management 

Council, Dover, DE, 398 pp. + apps. 

Mid-Atlantic Fishery Management Council, 1998d. Amendment 1 to the Bluefish Fishery 

Management Plan. Mid-Atlantic Fishery Management Council, 2 Vols., Dover, DE, 341 

pp. + apps. 

Mid-Atlantic Fishery Management Council, 1999. The Spiny Dogfish Fishery Management Plan. 

Mid-Atlantic Fishery Management Council, 292 pp. + apps. 

Miller, M.L., 1993. The rise of coastal marine tourism. Ocean and Coastal Management, 20: 

181-199. 

Minerals Management Service, 1989. Description of the Mid-Atlantic Environment, S.A. 

Abernathy (editor). Atlantic OCS Region, MMS 89-0064. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

245

Minerals Management Service, 1990. Final Environmental Report on Proposed Exploratory 

Drilling Offshore North Carolina, Volume 1, Section III.B.5, Marine Mammals and 

Section III.B.6, Reptiles. Atlantic OCS Region, Herndon, VA. 

Moein, S.E., J.A. Musick, J.A. Keinath, D.E. Barnard, M.L. Lenhardt, and R. George, 1994. 

Evaluation of Seismic Sources for Repelling Sea Turtles from Hopper Dredges. Virginia 

Institute of Marine Science, College of William and Mary, Gloucester Point, VA, final 

contract report to U.S. Army Engineer Waterways Experiment Station. As excerpted in: 

Sea Turtle Research Program Summary Report. Prepared by U.S. Army Engineer 

Waterways Experiment Station, Vicksburg, MS for U.S. Army Engineer Division, South 

Atlantic, Atlanta, GA and U.S. Naval Submarine Base, Kings Bay, GA, Technical Report 

CHL-97-31, NTIS ADA332588, 147 pp.. 

Moore, P.G., 1977. Inorganic particulate suspensions in the sea and their effects on marine 

animals. Oceanography and Marine Biology Annual Review, 15: 225-363. 

Morgan, R.P., V.J. Rasin, Jr., and L.A. Noe, 1983. Sediment effects on eggs and larvae of 

striped bass and white perch. Transactions of the American Fisheries Society, 112: 220-

224. 

Mortimer, J.A., 1982. Feeding Ecology of Sea Turtles. In: K.A. Bjorndal (editor), Biology and 

Conservation of Sea Turtles. Smithsonian Institution Press, Washington, DC, pp. 

103-109. 

Moser, M.L., S.W. Ross, S.W. Snyder, and R.C. Dentzman, 1995. Distribution of Bottom 

Habitats on the Continental Shelf from North Carolina. Marine Resources Research 

Institute, South Carolina Department of Natural Resources for the Southeast Area 

Monitoring and Assessment Program Bottom Mapping Workgroup. 

Murawski, W.S., 1969. A Study of Submerged Dredge Holes in New Jersey Estuaries with 

Respect to their Fitness as Finfish Habitat. New Jersey Department of Conservation and 

Economic Development, Division of Fish and Game, Miscellaneous Report No. 2M, 32 pp. 

Naqvi, S. and E. Pullen, 1982. Effects of Beach Nourishment and Borrowing on Marine 

Organisms. U.S. Army Corps of Engineers, Coastal Engineering Research Center, Fort 

Belvoir, VA, Miscellaneous Report No. 82-14. 

National Marine Fisheries Service, 1991a. Recovery Plan for the Humpback Whale (Megaptera 

novaeangliae). Prepared by the Humpback Whale Recovery Team for the National 

Marine Fisheries Service, Silver Spring, MD, 105 pp. 

National Marine Fisheries Service, 1991b. Recovery Plan for the Northern Right Whale 

(Eubalaena glacialis). Prepared by the Right Whale Recovery Team for the National 

Marine Fisheries Service, Silver Spring, MD, 86 pp. 

National Marine Fisheries Service, 1996. Endangered Species Act, Section 7 Consultation, 

Biological Opinion Concerning Dredging Activities Within the Philadelphia District of the 

U.S. Department of the Army. Prepared by the National Marine Fisheries Service, 

Northeast Regional Office, 43 pp. 

National Marine Fisheries Service, 1997. Regional Biological Opinion for Hopper Dredging of 

Channels and Beach Nourishment Activities in the Southeastern United States from North 

Carolina through Florida East Coast. October 1997. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

246

National Marine Fisheries Service, 1998. Marine Mammal Protection Act of 1972 Annual 

Report, January 1, 1997 to December 31, 1997. Office of Protected Resources, National 

Marine Fisheries Service, Silver Spring, MD. 

National Marine Fisheries Service, 1999. Fishery Management Plan for Atlantic Tunas, 

Swordfish, and Sharks, Volume II . National Marine Fisheries Service Division of Highly 

Migratory Species, Office of Sustainable Fisheries, Silver Spring, MD, 302 pp. 

National Marine Fisheries Service and U.S. Fish and Wildlife Service, 1991. Recovery Plan for 

U.S. Population of Atlantic Green Turtle. National Marine Fisheries Service, Washington, 

DC, 52 pp. 

National Marine Fisheries Service and U.S. Fish and Wildlife Service, 1992. Recovery Plan for 

the Kemp's Ridley Sea Turtle (Lepidochelys kempii). National Marine Fisheries Service, 

St. Petersburg, FL, 40 pp. 

National Marine Fisheries Service and U.S. Fish and Wildlife Service, 1993. Recovery Plan for 

Hawksbill Turtles in the U.S. Caribbean Sea, Atlantic Ocean, and Gulf of Mexico. National 

Marine Fisheries Service, St. Petersburg, FL, 47 pp. 

National Ocean Service, 1998. Geophysical Data System for Hydrographic Survey Data. 

Version 4.0, National Ocean Service, Washington, DC. 

National Research Council, 1995. Beach Nourishment and Protection. National Academy 

Press, 334 pp. 

Nelson, W.G., 1985. Physical and Biological Guidelines for Beach Restoration Projects. Part 1. 

Biological Guidelines. Florida Sea Grant College Program, Report No. 76. 

New England Fishery Management Council, 1998. Amendment 11 to the Northeast 

Multispecies Fishery Management Plan, Amendment 9 to the Atlantic Sea Scallop Fishery 

Management Plan, Amendment 1 to the Monkfish Fishery Management Plan, Amendment 

1 to the Atlantic Salmon Fishery Management Plan, Components of the Proposed Atlantic 

Herring Fishery Management Plan for Essential Fish Habitat, Volume 1. Prepared by the 

New England Fishery Management Council, Newburyport, MA. 

Newell, R.C., L.J. Seiderer, and D.R. Hitchcock, 1998. The impact of dredging works in coastal 

waters: A review of the sensitivity to disturbance and subsequent recovery of biological 

resources on the seabed. Oceanography and Marine Biology Annual Review, 36: 127-

178. 

Newell, R.C., D.R. Hitchcock, and L.J. Seiderer, 1999. Organic enrichment associated with 

outwash from marine aggregates dredging: A probable explanation for surface sheens 

and enhanced benthic production in the vicinity of dredging operations. Marine Pollution 

Bulletin, 38(9): 809-818. 

Nival, P. and S. Nival, 1976. Particle retention efficiencies of an herbivorous copepod, Acartia 

clausi (adult and copepodite stages): effects of grazing. Limnology and Oceanography, 

21(1): 24-38. 

North Carolina Division of Marine Fisheries, 1990. Assessment of North Carolina Commercial 

Finfisheries 1988-1989 Fishing Season. North Carolina Department of Environment, 

Health, and Natural Resources, Division of Marine Fisheries, Moorehead, City, NC, 160 

pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

247

Nyman, R.M. and D.O. Conover, 1988. The relation between spawning season and the 

recruitment of young-of-the-year bluefish, Pomatomus saltatrix, to New York. Fishery 

Bulletin, 86(2): 237-250. 

Oakwood Environmental Ltd., 1999. Strategic Cumulative Effects of Marine Aggregates 

Dredging (SCEMAD). Prepared for the U.S. Department of the Interior, Minerals 

Management Service, 175 pp. 

Odum, E.P., 1969. The strategies of ecosystem development. Science, 16: 262-270. 

Okihiro, M., R.T. Guza, and R.J. Seymour, 1991. Infragravity bound waves in shallow and deep 

water. EOS, Transactions of the American Geophysical Union, 72 (44/supp.): 253. 

Overholtz, W., 1998a. Atlantic Mackerel. In: S.H. Clark (editor), Status of Fishery Resources 

off the Northeastern United States for 1998. U.S. Department of Commerce, NOAA Tech 

Mem. NMFS-NE-115, pp. 106-107. 

Overholtz, W., 1998b. Butterfish. In: S.H. Clark (editor), Status of Fishery Resources off the 

Northeastern United States for 1998. U.S. Department of Commerce, NOAA Tech Mem. 

NMFS-NE-115, pp. 108-109. 

Overton, M.F., R.R. Grenier, Jr., E.K. Judge, and J.S. Fisher, 1999. Identification and analysis 

of coastal erosion hazard areas: Dare and Brunswick Counties, North Carolina. In: M. 

Crowell and S.P. Leathermen (editors), Coastal Erosion Mapping and Management. 

Journal of Coastal Research, Special Issue 28: 69-84. 

Oviatt, C.A., C.D. Hunt, G.A. Vargo, and K.W. Kopchynski, 1982. Simulation of a storm event in 

a marine microcosm. Journal of Marine Research, 39: 605-618. 

Paffenhofer, G.A., 1972. The effects of “red mud” on mortality, body weight, and growth of 

marine planktonic copepod, Calanus helgolandicus. Water, Air, and Soil Pollution, 

1: 314-321. 

Palermo, M.R., 1990. Workgroup 2 Summary. In: D.D. Dickerson and D.A. Nelson (compilers), 

Proceedings of the National Workshop on Methods to Minimize Dredging Impacts on Sea 

Turtles, Jacksonville, FL. U.S. Army Engineer Waterways Experiment Station, Vicksburg, 

MS, Miscellaneous Paper EL-90-5, pp. 76-80. 

Pearce, J.B., D.J. Radosh, J.V. Caracciolo, and F.W. Steimle, Jr., 1981. Benthic Fauna: Marine 

EcoSystems Analysis (MESA) Program, MESA New York Bight Project. MESA New York 

Bight Atlas Monograph 14, New York Sea Grant Institute, Albany, NY, 79 pp. 

Peddicord, R.K. and V.A. McFarland, 1978. Effects of Suspended Dredged Material on Aquatic 

Animals. U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, Technical 

Report D-78-29, 102 pp. + app. 

Peterson, C.G.J., 1913. Valuation of the Sea. II. The Animal Communities of the Sea-Bottom 

and Their Importance for Marine Zoogeography. Report of the Danish Biological Station 

to the Board of Agriculture, 21: 1-44. 

Pianka, E.R., 1970. On R- and K-selection. American Naturalist, 104: 592-597. 

Pielou, E.C., 1966. Species-diversity and pattern-diversity in the study of ecological succession. 

Journal of Theoretical Biology, 10: 370-383. 

Pilkey, O.H., W.J. Neal, S.R. Riggs, C.A. Webb, D.M. Bush, D.F. Pilkey, J. Bullock, and B.A. 

Cowan, 1998. The North Carolina Shore and Its Barrier Islands: Restless Ribbons of 

Sand. Duke University Press, Durham and London, 318 pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

248

Poiner, I.R. and R. Kennedy, 1984. Complex pattern of change in the macrobenthos of a large 

sandbank following dredging. I. Community analysis. Marine Biology, 78: 335-352. 

Rabalais, N.N. and D.F. Boesch, 1987. Dominant features and processes of continental shelf 

environments of the United States. In: D.F. Boesch and N.N. Rabalais (editors), LongTerm Environmental Effects of Offshore Oil and Gas Development. Elsevier, New York, 

NY, pp. 71-147. 

Reeves, R.R., G.K. Silber, and P.M. Payne, 1998. Draft Recovery Plan for the Fin Whale, 

Balaenoptera physalus and Sei whale, Balaenoptera borealis. Prepared for the Office of 

Protected Resources, National Marine Fisheries Service, Silver Spring, MD, 65 pp. 

Reine, K.J. and D.G. Clarke, 1998. Entrainment by Hydraulic Dredges - A Review of Potential 

Impacts. U.S. Army Engineer Research and Development Center, Vicksburg, MS, 

Dredging Operations and Environmental Research Technical Notes Collection, TN DOERE1. 

Reine, K.J., D.D. Dickerson, and D.G. Clarke, 1998. Environmental windows associated with 

dredging operations. U. S. Army Engineer Research and Development Center, Vicksburg, 

MS, DOER Technical Note TN DOER-E2. 

Renaud, P.E., W.G. Ambrose, S.R. Riggs, and D.A. Syster, 1996a. Multi-level effects of severe 

storms on an offshore temperate hard-bottom system: benthic sediments, macroalgae, 

and implications for fisheries. Marine Ecology, 17: 383-398. 

Renaud, P.E., S.R. Riggs, W.G. Ambrose, K.A. Schmid, and S.W. Snyder, 1996b. Biologicalgeological interactions: storm effects on microalga communities and implications for 

fisheries resources. Continental Shelf Research, 17: 37-56. 

Rennie S.E., J.L. Largier, and S.J. Lentz, 1999. Observations of a buoyancy current 

downstream of Chesapeake Bay. Journal of Geophysical Research, 104(C8): 18,227-

18,240. 

Research Planning, Inc., W.F. Baird & Associates, Ltd., and Applied Marine Sciences, Inc. 

2001. Development and Design of Biological and Physical Monitoring Protocols to 

Evaluate the Long-Term Impacts of Offshore Dredging Operations on the Marine 

Environment. A final report to the Minerals Management Service, U.S Department of the 

Interior, International Activities and Marine Minerals Division, Herndon, VA, OCS Report 

MMS 2001-089. 

Rhoads, D.C., 1974. Organism-sediment relations on the muddy seafloor. Oceanography and 

Marine Biological Annual Review, 12: 263-300. 

Rhoads, D.C. and L.F. Boyer, 1982. The effects of marine benthos on physical properties of 

sediments: a successional perspective. In: P.L. McCall and M.J.S. Tevesz (editors), 

Animal-Sediment Relations, The Biogenic Alteration of Sediments. Plenum Press, New 

York, NY, pp. 3-52. 

Rhoads, D.C. and J.D. Germano, 1982. Characterization of organism-sediment relations using 

sediment profile imaging: An efficient method of remote ecological monitoring of the 

seafloor (REMOTSTM System). Marine Ecology Progress Series, 8: 115-128. 

Rhoads, D.C. and J.D. Germano, 1986. Interpreting long-term changes in benthic community 

structure: a new protocol. Hydrobiologia, 142: 291-308. 

Rhoads, D.C., P.L. McCall, and J.Y. Yingst, 1978. Disturbance and production on the estuarine 

seafloor. American Science, 66: 577-586. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

249

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson, 1995. Marine Mammals 

and Noise. Academic Press, San Diego, 576 pp. 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J.H. Anderson, 1969. Hearing in the 

giant sea turtle, Chelonia mydas. Proceedings of the National Academy of Sciences, 

64(3): 884-890. 

Riggs, S.R., 1996. Sediment evolution and habitat function of organic-rich muds within the 

Albemarle estuarine system, North Carolina. Estuaries, 19: 169-185. 

Riggs, S.R., and D.K. Belknap, 1988. Upper Cenozoic processes and environments of the 

continental margin sedimentation. Eastern United States. In: R.E. Sheridan, J.A. Grow, 

(editors), The Atlantic Continental Margin of the United States. Geology of North America. 

Geological Survey of America Decade of North American Geology I-2, pp. 131-176. 

Riggs, S.R., L.L. York, J.F. Wehmiller, and S.W. Snyder, 1992. Depositional patterns resulting 

from high-frequency Quaternary sea-level fluctuations in northeastern North Carolina. In: 

C.H. Fletcher, J.F. Wehmiller (editors), Quaternary Coasts of the United States. Marine 

and Lacustrine Systems. SEPM Special Publication 48: 141-153. 

Riggs S.R., W.J. Cleary, and S.W. Snyder, 1995. Influence of inherited geologic formwork on 

barrier shoreface morphology and dynamics. Marine Geology, 126: 213-234. 

Riggs S.R., W.G. Ambrose Jr., J.W. Cook, Scott W. Snyder, and Stephen W. Snyder, 1998. 

Sediment production on sediment-starved continental margins: the interrelationship 

between hardbottoms, sedimentological and benthic community processes, and storm 

dynamics. Journal of Sedimentary Research, 68(1): 155-168. 

Robins, C.R., 1957. Effects of storms on the shallow-water fish fauna of southern Florida with 

records of fishes from Florida. Bulletin of Marine Science in the Gulf and Caribbean, 7(3): 

266-275. 

Roden, C., 1998. Cruise Results: Summer Atlantic Marine Mammal Survey, NOAA Ship 

Relentless Cruise RS 98-01(3). National Marine Fisheries Service, Southeast Fisheries 

Science Center, Mississippi Laboratories, Pascagoula Facility, Pascagoula, MS. 

Rogers, R.M., 1977. Trophic Interrelationships of Selected Fishes on the Continental Shelf of 

the Northern Gulf of Mexico. Ph.D. dissertation, Texas A&M University, College Station, 

TX, 244 pp. 

Rosenthal, H.S., 1971. Effects of “red mud” on embryos and larvae of the herring Clupea 

harengus. Helgolaender Wiss. Meeresuntersuchungen, 22: 366-376. 

Rosman, I., G.S. Boland, L. Martin, and C. Chandler, 1987. Underwater Sightings of Sea 

Turtles in the Northern Gulf of Mexico. U.S. Department of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA, OCS Study MMS 

87-0107, 37 pp. 

Ross, S.W., 1985. An Assessment of the Distribution and Composition of the Ichthyofauna in 

the Proposed VACAPES EMPRESS II Area off North Carolina. Final Report to the 

Department of the Navy, Naval Sea Systems Command, PO No. N0002485RQ17015. 

Ross, S.W., F.C. Rhode, and D.G. Lindquist, 1988. Endangered, threatened and rare fauna of 

North Carolina. Part II. A re-evaluation of the marine and estuarine species. Occasional 

Papers of the North Carolina Biological Survey, 1988-7, pp. 1-20. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

250

Rotunno, T. and R.K. Cowen, 1997. Temporal and spatial spawning patterns of the Atlantic 

butterfish, Peprilus triacanthus, in the South and Middle Atlantic Bights. Fishery Bulletin, 

95(4): 785-799. 

Saloman, C.H., 1974. Physical, Chemical, and Biological Characteristics of Nearshore Zone of 

Sand Key, Florida, Prior to Beach Restoration. National Marine Fisheries Service, Gulf 

Coastal Fisheries Center, Panama City Laboratory, Panama City, FL. 

Saloman, C.H., S.P. Naughton, and J.L. Taylor, 1982. Benthic Community Response to 

Dredging Borrow Pits, Panama City Beach, Florida. U.S. Army Corps of Engineers, 

Coastal Engineering Research Center, Fort Belvoir, VA, Miscellaneous Report No. 82-3, 

138 pp. 

Sanders, H.L., 1958. Benthic studies in Buzzards Bay. I. Animal-sediment relationships. 

Limnology and Oceanography, 3: 245-258. 

Sandifer, P.A., J.V. Miglarese, D.R. Calder, J.J. Manzi, and L.A. Barclay, 1980. Ecological 

Characterization of the Sea Island Coastal Region of South Carolina and Georgia. Volume 

III: Biological Features of the Characterization Area. U.S. Fish and Wildlife Service, Office 

of Biological Services, Washington, D.C., FWS/OBS-79/42, 620 pp. 

SAS Institute Inc., 1989. SAS/STAT Users Guide, Version 6, Fourth Edition, Volume 1. SAS 

Institute Inc., Cary, NC, 943 pp. 

Savidge, D.K., J.M. Bane, Jr., 2001. Wind and Gulf Stream influences on along-shelf transport 

and off-shelf export at Cape Hatteras, North Carolina. Journal of Geophysical Research, 

106(C6): 11,505-11,528. 

Schaeff, C.M., S.D. Kraus, M.W. Brown, and B.N. White, 1993. Assessment of the population 

structure of western North Atlantic right whales (Eubalaena glacialis) based on sighting 

and mtDNA data. Canadian Journal of Zoology, 71(2): 339-345. 

Schaffner L.C. and D.F. Boesch, 1982. Spatial and temporal resource use by dominant benthic 

Amphipoda (Ampeliscidae and Corophiidae) on the Middle Atlantic Bight outer continental 

shelf. Marine Ecology Progress Series, 9: 231-243. 

Schwartz, F.J., 1978. Behavioral and tolerance responses to cold water by three species of sea 

turtles (Reptilia, Cheloniidae) in North Carolina. Florida Marine Research Publications, 

33: 16-18. 

Scott, L.C. and F.S. Kelley, 1998. An Evaluation and Comparison of Benthic Community 

Assemblages and Surf Clam Populations Within the Offshore Sand Borrow Site for the 

Great Egg Harbor Inlet and Peck Beach, Ocean City, New Jersey Project. Prepared for 

the U.S. Army Corps of Engineers, Philadelphia District, Philadelphia, PA by Versar, Inc., 

Columbia, MD, 36 pp. + app. 

Shalowitz, A.L., 1964. Shoreline and Sea Boundaries, Volume 2. U.S. Department of 

Commerce Publication 10-1, U.S. Coast and Geodetic Survey, U.S. Government Printing 

Office, Washington, DC, 420 pp. 

Shaver, D.J., 1991. Feeding ecology of wild and headstarted Kemp's Ridley sea turtles in south 

Texas waters. Journal of Herpetology, 25(3): 327-334. 

Sherk, J.A., Jr., 1971. The Effects of Suspended and Deposited Sediment on Estuarine 

Organisms: Literature Summary and Research Needs. University of Maryland, Natural 

Resources Institute, Chesapeake Biological Laboratory Contribution No. 43, 73 pp. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

251

Sherk, J.A., Jr., 1972. Current status of the knowledge of the biological effects of suspended 

and deposited sediments in Chesapeake Bay. Chesapeake Science, 13 (Suppl.): S137-

S144. 

Sherk, J.A., Jr. and L.E. Cronin, 1970. The Effects of Suspended and Deposited Sediments on 

Estuarine Organisms, an Annotated Bibliography of Selected References. University of 

Maryland, Chesapeake Biological Laboratory, Natural Resources Institute, Reference No. 

70-19, 62 pp. 

Sherk, J.A., J.M. O'Connor, and D.A. Newman, 1975. Effects of suspended and deposited 

sediments on estuarine environments. In: L.F. Cronin (editor), Estuarine Research 

Volume 2. Academic Press, New York, NY, pp. 541-558. 

Sherman, K., R.J. Green, J.R. Goulet, and L. Ejsymont, 1983. Coherence in zooplankton of a 

large northwest Atlantic ecosystem. Fishery Bulletin, 81(4): 855-862. 

Sherman, K., W. Smith, W. Morse, M. Berman, J. Green, and L. Ejsymont, 1984. Spawning 

strategies of fishes in relation to circulation, phytoplankton production, and pulses in 

zooplankton off the northeastern United States. Marine Ecology Progress Series, 18: 

1-19. 

Shideler, G.L. and D.J.P. Swift, 1972. Seismic reconnaissance of post-Miocene deposits, 

middle Atlantic continental shelf- Cape Henry, Virginia to Cape Hatteras, North Carolina. 

Marine Geology, 12: 165-185. 

Slay, C.K., 1995. Sea Turtle Mortality Related to Dredging Activities in the Southeastern U.S.: 

1991. In: J.I. Richardson and T.H. Richardson (compilers), Proceedings of the Twelfth 

Annual Workshop on Sea Turtle Biology and Conservation, Jekyll Island, GA, NOAA 

Technical Memorandum NMFS-SEFSC-361, pp. 132-133. 

Smith, J.M., Resio, D.T., and Zundel, A.K., 1999. STWAVE: Steady-state spectral wave model. 

Instruction Report CHL-99-March 1999, U.S. Army Engineering Waterways Experiment 

Station, Vicksburg, MS. 

Smith, W.G. (editor), 1988. Analysis and Evaluation of Ichthyoplankton Survey Data from the 

Northeast Continental Shelf Ecosystem. NOAA-TM-NMFS-F/NEC-57, 133 pp. 

Smith, W. and W. Morse, 1988. Seasonal distribution, abundance, and diversity patterns of fish 

eggs and larvae in the Middle Atlantic Bight. In: A.L. Pacheco (editor), Characterization of 

the Middle Atlantic Water Management Unit of the Northeast Regional Action Plan. 

NOAA-TM-NMFS-F/NEC- 56, pp. 177-189. 

Smith, W., P. Berrien, and T. Potthoff, 1994. Spawning patterns of bluefish, Pomatomus 

saltatrix, in the northeast continental shelf ecosystem. Bulletin of Marine Science, 54(1): 

8-15. 

Snedden, J.W., R.W. Tillman, R.D. Kreisa, W.J. Schweller, S.J. Culver, and R.D. Winn, 1994. 

Stratigraphy and genesis of a modern shoreface-attached sand ridge, Peahala Ridge, 

New Jersey. Journal of Sedimentary Research, Section B: Stratigaphy and Global 

Studies, B64(4): 560-581. 

Snelgrove, P.V.R. and C.A. Butman, 1994. Animal-sediment relationships revisited: cause 

versus effect. Oceanography and Marine Biology Annual Review, 32: 111-177. 

Snyder, S.W., 1993. North Carolina Outer Banks Beach Nourishment Sand Resource Study, 

First Interim Report: Shallow High-Resolution Seismic Survey, Offshore Nags Head Area. 

North Carolina Geologic Survey Open-File Report 93-38, 47 p. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

252

Snyder, S.W., 1997a. Evaluation of Potential Sand Resources for Beach Nourishment off the 

North Dare County Coastline. Final Report to the U.S. Army Corps of Engineers, 

Wilmington District. 

Snyder, S.W., 1997b. North Carolina Outer Banks Beach-Nourishment/Sand-Resource Study, 

Second Interim Report: Seismic Stratigraphic Sections from Kitty Hawk and Nags Head 

Offshore Areas. Unpublished report prepared for the North Carolina Geologic Survey and 

the Minerals Management Service/North Carolina Sand Resources Task Force, 48 p. 

South Atlantic Fishery Management Council, 1998. Habitat Plan for the South Atlantic Region: 

Essential Fish Habitat Requirements for Fishery Management Plans of the South Atlantic 

Fishery Management Council. South Atlantic Fishery Management Council, Charleston, 

SC. 

Southeast Area Monitoring and Assessment Program - South Atlantic, 2001. Distribution of 

Bottom Habitats on the Continental Shelf from North Carolina Through the Florida Keys. 

SEAMAP-SA Bottom Mapping Workgroup, Atlantic States Marine Fisheries Commission, 

Washington, D.C., 166 pp. 

Stephenson, W.W.T., S.D. Cook, and S.J. Newland, 1978. The macrobenthos of the Middle 

Banks of Moreton Bay. Memoirs of the Queensland Museum, 18: 95-118. 

Stern, E.M. and W.B. Stickle, 1978. Effects of Turbidity and Suspended Material in Aquatic 

Environments: Literature Review. U.S. Army Engineer Waterways Experiment Station, 

Vicksburg, MS, Technical Report D-78-21, 117 pp. 

Stubblefield, W.L., D.W. McGrail, and D.G. Kersey, 1984. Recognition of transgressive and 

post-transgressive sand ridges on the New Jersey continental shelf. In: R.W. Tillman and 

C.T. Siemers (editors), Siliclastic Shelf Sediments, Society of Economic Paleontologists 

and Mineralogists, Special Publication 34: 1-23. 

Studt, J.F., 1987. Amelioration of maintenance dredging impacts on sea turtles, Canaveral 

Harbor, Florida. In: W. Witzell (editor), Ecology of East Florida Sea Turtles. Proceedings 

of the Cape Canaveral, Florida Sea Turtle Workshop, Miami, FL, NOAA Technical Report 

NMFS 53, pp. 55-58. 

Sullivan, B.K. and D. Hancock, 1977. Zooplankton and dredging: research perspectives from a 

critical review. Water Research Bulletin, 13(3): 461-468. 

Swift, D.J.P., 1976. Continental shelf sedimentation. In: D.J. Stanley and D.J.P. Swift (editors), 

Marine Sediment Transport and Environmental Management. Wiley and Sons, New York, 

NY, pp. 311-350. 

Swift, D.J.P., J.W. Kofoed, F.P. Salsbury, and P. Sears, 1972. Holocene evolution of the shelf 

surface, central and southern Atlantic shelf of North America. In: D.J.P. Swift, D.B 

Duane, and O.H. Pilkey (editors), Shelf Sediment Transport: Process and Pattern. 

Dowden Hutchinson, and Ross. Stroudsburg, PA, pp. 499-575. 

Swingle, W.M., S.G. Barco, T.D. Pitchford, W.A. McLellan, and D.A. Pabst, 1993. Appearance 

of juvenile humpback whales feeding in the nearshore waters of Virginia. Marine Mammal 

Science, 9(3): 309-315. 

Taylor, A.S., 1990. The Hopper Dredge. In: D.D. Dickerson and D.A. Nelson (compilers), 

Proceedings of the National Workshop on Methods to Minimize Dredging Impacts on Sea 

Turtles, Jacksonville, FL, U.S. Army Engineer Waterways Experiment Station, Vicksburg, 

MS, Miscellaneous Paper EL-90-5, pp. 59-63. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

253

Taylor, A.S., 1999. Personal communication with Mark Byrnes. 

Terciero, M. 1998. Bluefish. In: S.H. Clark (editor), Status of Fishery Resources off the 

Northeastern United States for 1998. U.S. Department of Commerce, NOAA Technical 

Memorandum NMFS-NE-115, pp. 110-111. 

Thayer, C.W., 1983. Sediment-mediated biological disturbance and the evolution of marine 

benthos. In: M.J.S. Tevesz and P.L. McCall (editors), Biotic Interactions in Recent and 

Fossil Benthic Communities. Plenum Press, NY, pp. 479-625. 

Thistle, D., 1981. Natural physical disturbances and communities of marine soft bottoms. 

Marine Ecology Progress Series, 6: 223-228. 

Thompson, J.R., 1973. Ecological Effects of Offshore Dredging and Beach Nourishment: A 

Review. U.S. Army Engineer Waterways Experiment Station MP 1-73, U.S. Army Corps 

of Engineers, Coastal Engineering Research Center, Fort Belvoir, VA, Report 1-73. 

Thorson, G., 1957. Bottom communities (sublittoral or shallow shelf). Geological Society of 

America Memoir, 67: 461-534. 

Thorson, G., 1966. Some factors influencing the recruitment and establishment of marine 

benthic communities. Netherlands Journal of Sea Research, 3(2): 267-293. 

True, F.W., 1887. The Turtle and Terrapin Fisheries. In: The Fisheries and Fishery Industries 

of the United States, Vol. 2, Section 5, Part 19. U.S. Government Printing Office, 

Washington, DC., pp. 495-499. As cited in Minerals Management Service, 1990. Final 

Environmental Report on Proposed Exploratory Drilling Offshore North Carolina. Atlantic 

OCS Region, Herndon, VA. 

Turbeville, D.B. and G.A. Marsh, 1982. Benthic Fauna of an Offshore Borrow Area in Broward 

County, Florida. U.S. Army Corps of Engineers, Coastal Engineering Research Center, 

Miscellaneous Report 82-1, 43 pp. 

Uchupi, E., 1965. Map Showing Relation of Land and Submarine Topography, Nova Scotia to 

Florida. U.S. Geological Survey Miscellaneous Investigations, Map 1-451. 

U.S. Environmental Protection Agency, 1997. Supplement to the Environmental Impact 

Statement on the New York Dredged Material Disposal Site Designation for the 

Designation of the Historic Area Remediation Site (HARS) in the New York Bight Apex. 

Prepared by U.S. Environmental Protection Agency, Region 2, New York, NY with the 

assistance of Battelle, Duxbury, MA. 

U.S. Fish and Wildlife Service, 1996. Florida Manatee Recovery Plan (Trichechus manatus 

latirostris), Second Revision. Prepared by the Florida Manatee Recovery Team for the 

Southeast Region, U.S. Fish and Wildlife Service, Atlanta, GA. Approved January 29, 

1996. 

USACE, 1984. Shore Protection Manual. U.S. Army Engineer Waterways Experiment Station, 

Coastal Engineering Research Center, Vicksburg, MS. 

USACE, 1999. Hopper Dredge Sea Turtle Deflector Draghead and Operational Requirements. 

Online at http://www.saj.usace.army.mil/pd/turtle.htm. 

USACE, 2000. Final Feasibility Report and Environmental Impact Statement on Hurricane 

Protection and Beach Erosion Control: Dare County Beaches (Bodie Island Portion), Dare 

County, North Carolina, Volume I. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

254

USACE, 2002. Environmental Assessment, Manteo (Shallowbag) Bay Project Maintenance of 

Oregon Inlet Bar Channel, Channel Widener, Dare County, North Carolina. U.S. Army 

Corps of Engineers, Wilmington District, Wilmington, NC. 

USACE, Wilmington District, 1980. Mantteo Bay, North Carolina, Design Memorandum 2, 

General Design Memorandum, Phase II, Project Design, Appendices 1 through 5. 

USGS, 2001. The Coastal Sedimentary System: Northern North Carolina. U.S. Geological 

Survey Information Sheet, http://woodshole.er.usgs.gov/project-pages/northcarolina/. 

Van Dolah, R.F., 1996. Impacts of Beach Nourishment on the Benthos: What Have We 

Learned? Proceedings of the Twenty-fourth Annual Benthic Ecology Meeting, Columbia, 

SC, p. 82. 

Van Dolah, R.F., D.R. Calder, and D.M. Knott, 1984. Effects of dredging and open-water 

disposal on benthic macroinvertebrates in a South Carolina estuary. Estuaries, 7: 28-37. 

Van Dolah, R.F., P.H. Wendt, R.M. Martore, M.V. Levisen, and W.A. Roumillat, 1992. A 

Physical and Biological Monitoring Study of the Hilton Head Beach Nourishment Project. 

Final Report submitted to the Town of Hilton Head Island and South Carolina Coastal 

Council by the South Carolina Wildlife and Marine Resources Department, Marine 

Resource Research Institute, 159 pp. 

Van Dolah, R.F., R.M. Martore, and M.V. Levisen, 1993. Supplemental Report for the Physical 

and Biological Monitoring Study of the Hilton Head Beach Nourishment Project. Prepared 

by the South Carolina Marine Resources Division, Marine Resources Research Institute 

for the for the Town of Hilton Head Island, SC. 

Van Dolah, R.F., B.J. Digre, P.T. Gayes, P. Donovan-Ealy, and M.W. Dowd, 1998. An 

Evaluation of Physical Recovery Rates in Sand Borrow Sites Used for Beach Nourishment 

Projects in South Carolina. Final report to the U.S. Department of the Interior, Minerals 

Management Service, Office of International Activities and Marine Minerals by the South 

Carolina Department of Natural Resources, Marine Resources Research Institute, 76 pp. 

+ app. 

Vecchione, M., 1981. Aspects of the early life history of Loligo pealei (Cephalopoda; Myopsida). 

Journal of Shellfish Research, 1: 171-180. 

Vinyard, G.L. and J.W. O’Brien, 1976. Effects of light and turbidity on the reactive distance of 

bluegill (Lepomis macrochirus). Journal of the Fisheries Research Board of Canada, 33: 

2,845-2,849. 

Walker, T.A. and G. O'Donnell, 1981. Observations on nitrate, phosphate, and silicate in 

Cleveland Bay, Northern Queensland. Australian Journal of Marine and Freshwater 

Research, 32: 877-887. 

Waring, G.T., D.L. Palka, P.J. Clapham, S. Swartz, M. Rossman, T. Cole, L.J. Hansen, K.D. 

Bisack, K. Mullin, R.S. Wells, D.K. Odell, and N.B. Barros, 1999. U.S. Atlantic and Gulf of 

Mexico Marine Mammal Stock Assessments - 1999. NOAA Technical Memorandum 

NMFS-NEFSC, 200 p. 

Warlen, S.M. and J.S. Burke, 1990. Immigration of fall/winter spawning marine fishes into a 

North Carolina estuary. Estuaries, 13: 453-461. 

Weber, M., 1995. Kemp's Ridley Sea Turtle, Lepidochelys kempii. In: P.T. Plotkin (editor), 

National Marine Fisheries Service and U. S. Fish and Wildlife Service Status Reviews for 

Sea Turtles Listed under the Endangered Species Act of 1973. Silver Spring, MD. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

255

Werner, S.A. and A.M. Landry, Jr., 1994. Feeding ecology of wild and head started Kemp's 

Ridley sea turtles (Lepidochelys kempii). In: K.A. Bjorndal, A.B. Bolten, D.A. Johnson, 

and P.J. Eliazar (compilers), Proceedings of the Fourteenth Annual Symposium on Sea 

Turtle Biology and Conservation, NOAA Tech. Memo. NMFS-SEFSC-351, U.S. 

Department of Commerce, Miami, FL, pp. 163. 

Weston, D.P., 1988. Macrobenthos-sediment relationships on the continental shelf off Cape 

Hatteras, North Carolina. Continental Shelf Research, 8(3): 267-286. 

Wigley, R.L. and R.B. Theroux, 1981. Atlantic Continental Shelf and Slope of the United StatesMacrobenthic Invertebrate Fauna of the Middle Atlantic Bight Region-Faunal Composition 

and Quantitative Distribution. U.S. Geological Survey Professional Paper 529-N, 198 pp. 

Wilber, D.H. and D.G. Clarke, 2001. Biological effects of suspended sediments: a review of 

suspended sediment impacts on fish and shellfish with relation to dredging activities in 

estuaries. North American Journal of Fisheries Management, 21: 855-875. 

Wilber, P. and M. Stern, 1992. A re-examination of infaunal studies that accompany beach 

nourishment projects. In: New Directions in Beach Management: Proceedings of the 5th 

Annual National Conference on Beach Preservation Technology, Florida Shore and 

Beach Preservation Association, Tallahassee, FL, pp. 242-257. 

Wiley, D.N., R.A. Asmutis, T.D. Pitchford, and D.P. Gannon, 1995. Stranding and mortality of 

humpback whales, Megaptera novaeangliae, in the mid-Atlantic and southeast United 

States, 1985-1992. Fishery Bulletin, 93: 196-205. 

Williams, A.B., 1984. Shrimp, Lobsters and Crabs of the Atlantic Coast of the Eastern U.S., 

from Maine to Florida. Smithsonian Institution Press, Washington, D.C., 550 pp. 

Williams, S.J., 1992. Coasts in Crisis. U.S. Geological Survey Circular 1075, 32 pp. 

Winn, H.E. (editor), 1982. A Characterization of Marine Mammals and Turtles in the Mid- and 

North Atlantic Areas of the U.S. Outer Continental Shelf. Final report of the Cetacean and 

Turtle Assessment Program. University of Rhode Island, Kingston, RI, Prepared for U.S. 

Department of the Interior, Bureau of Land Management, Washington, DC, Available 

through National Technical Information Service, Springfield, VA, PB83-215855. 

Woodworth-Lynas, C. and L. Davis, 1996. Proposed Marine Mining Technologies and 

Mitigation Techniques: A Detailed Analysis with Respect to the Mining of Specific Offshore 

Mineral Commodities. Final Report. Prepared by the Centre for Cold Ocean Resources 

Engineering for the U.S. Department of the Interior, Minerals Management Service. 

Contract No. 14-35-0001-30723, OCS Report MMS 95-0003, 279 pp. + 6 Appendices. 

Wright, D.G., 1977. Artificial Islands in the Beaufort Sea: A Review of Potential Impacts. 

Department of Fisheries and Environment, Winnipeg, Manitoba, 38 pp. 

Wright, L.D., 1993. Micromorphodynamics of the inner continental shelf: a Middle Atlantic Bight 

case study. Journal of Coastal Research, Special Issue 15: 93-124. 

Wright, L.D., J.D. Boon, M.O. Green, J.H. List, 1986. Response of the mid-shoreface of the 

southern mid-Atlantic Bight to a “Northeaster”. Geo-Marine Letters, 6: 153-160. 

Wright, L.D., J.D. Boon, S.C. Kim, and J.H. List, 1991. Modes of cross-shore sediment 

transport on the shoreface of the Middle Atlantic Bight. Marine Geology, 96: 19-51. 
Collection of Environmental Data Within Sand Resource Areas Offshore North Carolina and the Environmental 

Implications of Sand Removal for Coastal and Beach Restoration 

MMS Study 2000-056 

256

Wright, L.D., J.P. Xu and O.S. Madsen, 1994. Across-shelf benthic transport processes on the 

inner shelf of the Middle Atlantic Bight during the “Halloween Storm” of 1991. Marine 

Geology, 118: 61-77. 

Xu, J.P. and L.D. Wright, 1998. Observations of wind-generated shoreface currents off Duck, 

North Carolina. Journal of Coastal Research, 14(2): 610-619. 

Young, D.K. and D.C. Rhoads, 1971. Animal-sediment relations in Cape Cod Bay, 

Massachusetts. I. A transect study. Marine Biology, 11: 242-254. 

Zajac, R.N. and R.B. Whitlatch, 1982. Responses of estuarine infauna to disturbance. I. Spatial 

and temporal variation of initial recolonization. Marine Ecology Progress Series, 10: 1-14. 

Zawila, J.S., 1994. Analysis of a Seismic Air Gun Acoustic Dispersal Technique at the Fort 

Pierce Sea Turtle Trial Site. Contract report to U.S. Army Engineer Waterways 

Experiment Station, as excerpted in: Sea Turtle Research Program Summary Report. 

Prepared by U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS for U.S. 

Army Engineer Division, South Atlantic, Atlanta, GA and U.S. Naval Submarine Base, 

Kings Bay, GA, Technical Report CHL-97-31, NTIS ADA332588, 147 pp.