DRAFT

DETAILED PROJECT REPORT AND 

ENVIRONMENTAL ASSESSMENT

MANTEO, OLD HOUSE CHANNEL, NC 

SECTION 204 BENEFICIAL USE OF DREDGED 

MATERIAL RESTORATION PROJECT

Beneficial Use of Dredged Material

Section 204 of the Water Resources Development Act of 1992, as amended

March 2013

Image source: http://www.ncfisheries.net/shellfish/recycle1.htm

Wilmington District
Detailed Project Report and Environmental Assessment

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Detailed Project Report and Environmental Assessment

Manteo, Old House Channel, NC Section 204 Project

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Contents

Executive Summary............................................................................................................ 1

1.0 STUDY AUTHORITY AND BACKGROUND.................................................... 3

2.0 STUDY GOAL, LOCATION, AND SCOPE......................................................... 4

2.1 Study Goal............................................................................................................ 4

2.2 Study Area Location............................................................................................. 4

2.3 Study Scope & Process ........................................................................................ 7

3.0 PRIOR STUDIES, REPORTS, AND EXISTING PROJECTS.............................. 7

3.1 Prior Studies and Reports..................................................................................... 7

3.2 Existing Projects................................................................................................. 10

4.0 EXISTING AND PROJECTED FUTURE – WITHOUT PROJECT 

CONDITIONS .................................................................................................................. 13

4.1 General Environmental Setting .......................................................................... 13

4.1.1 Climate........................................................................................................ 14

4.1.2 Tides, Currents and Sea Level Rise ............................................................ 15

4.1.4 Current Land Use in Project Area............................................................... 19

4.2 Biotic Communities............................................................................................ 20

4.2.1 Aquatic Habitats.......................................................................................... 20

4.2.2 Bird Islands................................................................................................. 25

4.2.3 Wetlands ..................................................................................................... 26

4.3 Threatened and Endangered Species.................................................................. 27

4.4 Benthic Resources.............................................................................................. 31

4.5 Essential Fish Habitat (EFH) and Fisheries.......................................................... 32

4.6 Sediments.............................................................................................................. 35

4.7 Coastal Processes.................................................................................................. 36

4.8 Air Quality ............................................................................................................ 36

4.9 Socio-Economics and Recreation ......................................................................... 37

4.10 Cultural Resources.............................................................................................. 38

4.11 Hazardous, Toxic, and Radioactive Wastes ................................................... 38

4.12 Floodplains.......................................................................................................... 38

4.13 Other Environmental Considerations.................................................................. 39

5.0 PLAN FORMULATION AND ALTERNATIVE EVALUATION.......................... 39
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5.1 Public Concern ................................................................................................... 39

5.2 Assessment of Problems, Opportunities, Objectives and Constraints ............... 40

5.2.1 Problems and Opportunities........................................................................ 40

5.2.2 Planning Objectives.................................................................................... 40

5.2.3 Planning Constraints...................................................................................... 41

5.3 Potential Restoration Alternatives...................................................................... 41

5.3.1 Description of Measures................................................................................ 42

5.3.2 Preliminary Screening of Restoration Measures............................................ 43

5.3.3 Final Array of Alternatives............................................................................ 47

5.4 Comparison of Alternatives ............................................................................... 57

5.4.1 “Base Plan” Costs.......................................................................................... 57

5.4.2 Costs of Alternatives...................................................................................... 58

5.4.3 Ecological Output Analysis of Alternatives ............................................... 58

5.4.4 Cost Effectiveness/Incremental Cost Analysis........................................... 66

5.5 Screening of Alternative Plans........................................................................... 71

5.6 Resource Significance ........................................................................................ 72

5.6.1 Institutional Significance. ........................................................................... 72

5.6.2 Public Significance. .................................................................................... 74

5.6.3 Technical Significance................................................................................ 75

5.7 The Ecosystem Restoration Plan........................................................................ 76

5.7.1 Partnership Context..................................................................................... 77

5.7.2 Reasonableness of Costs............................................................................. 77

5.8 Plan Selection..................................................................................................... 77

5.8.1 The NER/Preferred Plan ............................................................................. 77

5.8.2 NED/Optimum Tradeoff Plan..................................................................... 77

5.8.3 Locally Preferred Plan ................................................................................ 78

5.8.4 Designation of the Tentatively-Selected Plan............................................. 78

6.0 TENTATIVELY-SELECTED PLAN .................................................................. 78

6.1 Plan Description ................................................................................................. 78

6.2 Real Estate Requirements................................................................................... 79

6.3 Operation, Maintenance and Replacement Considerations................................ 82

6..4 Monitoring and Adaptive Management Plan........................................................ 82

6.5 Detailed Cost Estimate for Tentatively-Selected Plan ................................... 85

6.6 Cost Sharing ....................................................................................................... 85
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7.0 SUMMARY OF ENVIRONMENTAL IMPACTS.............................................. 86

7.1 General Environmental Conditions.................................................................... 86

7.1.1 Climate........................................................................................................ 86

7.1.2 Tides, Currents, and Sea Level Rise ........................................................... 86

7.1.3 Water Quality.............................................................................................. 86

7.1.4 Current Land Use in Project Area............................................................... 87

7.2 BIOTIC COMMUNITIES ................................................................................. 87

7.2.1 Aquatic Habitats.......................................................................................... 87

7.2.2 Bird Islands................................................................................................. 88

7.2.3 Wetlands ..................................................................................................... 88

7.3 Threatened and Endangered Species.................................................................. 89

7.4 Benthic Resources.............................................................................................. 90

7.5 Essential Fish Habitat (EFH) and Fisheries ....................................................... 90

7.6 Sediments........................................................................................................... 92

7.7 Coastal Processes ............................................................................................... 92

7.8 Air Quality.......................................................................................................... 92

7.9 Socio-Economics and Recreation....................................................................... 92

7.10 Cultural Resources.......................................................................................... 93

7.11 Hazardous, Toxic, and Radioactive Wastes ................................................... 93

7.12 Floodplains ..................................................................................................... 93

7.13 Cumulative Impacts.............................................................................................. 93

8.0 COMPLIANCE WITH ENVIRONMENTAL PROTECTION STATUTES AND 

EXECUTIVE ORDERS ................................................................................................... 95

9.0 SUMMARY COORDINATION, PUBLIC VIEWS, AND COMMENTS.......... 97

9.1 Scoping Comments and Responses.................................................................... 97

9.2 Stakeholder Meetings......................................................................................... 97

10.0 PLAN IMPLEMENTATION ............................................................................... 97

10.1 Non-Federal Responsibilities............................................................................... 97

10.2 Federal Responsibilities.................................................................................. 98

10.3 Work-in-Kind ................................................................................................. 99

10.4 Project Partnership Agreement (PPA)............................................................ 99

10.5 Sponsor Views................................................................................................ 99

11.0 RECOMMENDATIONS...................................................................................... 99

12.0 DRAFT FINDING OF NO SIGNIFICANT IMPACT...................................... 100

13.0 REFERENCES ................................................................................................... 100
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List of Tables

Table 4.01 Pertinent Tide Data

Table 4.02 Breakdown of Resource Coverage in Project Study Area based 

on Detailed Side-Scan Survey

Table 4.03 Endangered and Threatened Species Occurring in Project 

Vicinity

Table 4.04 Essential Fish Habitat (EFH) Species Present in Pamlico Sound, 

Dare County, North Carolina. Source: NMFS, Beaufort, North 

Carolina, October 1999

Table 4.05 Categories of Essential Fish Habitat and Habitat Areas of 

Particular Concern in Southeast States

Table 5.01 First Array for Evaluation and Screening of 

Measures/Alternatives

Table 5.02 Second Array for Evaluation and Screening of 

Measures/Alternatives

Table 5.03 Final Array of Alternatives

Table 5.04 Base Plan Costs for Manteo, Old House Channel, NC

Table 5.05 Cost of Alternatives

Table 5.06 HSI Variables to Assess Suitability for Oyster Larvae

Table 5.07 HSI Variables to Assess Suitability for Adult Oysters

Table 5.08 HSI Computations based on HEP

Table 5.09 Oyster Areas and Outputs for Various Alternatives

Table 5.10 Cost and Performance Summary for Plan Selection

Table 5.11 Results of Incremental Cost Analysis

Table 6.01 Real Estate Cost Estimate

Table 6.02 Total Project Costs

Table 6.03 Monitoring Cost

Table 7.01 Summary of Environmental Impacts

Table 8.01 Listing of Public Laws and Compliance Status

List of Figures

Figure 2.01 Project Study Area

Figure 2.02 Project Study Area (Yellow Box) in Relation to Surrounding 

Project Vicinity

Figure 3.01 Map Showing Proximity between Nearby NCDMF Oyster 

Sanctuaries and the Project Study Area

Figure 4.01 General Environmental Setting

Figure 4.02 Plot of Tide Levels Oregon Inlet Marina, NC – NOAA Website
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Figure 4.03 Plot of Sea-Level-Rise 50-Year Projections based upon 

Historical and Accelerated Rates

Figure 4.04 Resources Mapped within Project Study Area along with 

Existing Disposal Islands (Sonar Survey Mapping, Duck Research 

Center, Side-scan Survey – July-Sept. 2009)

Figure 4.05 Major Sessile Shellfish Habitat in Pamlico Sound

Figure 5.01 Map of Site Selection Screening Process

Figure 5.02 Typical Sheetpile & Stone Alternative Cross Section

Figure 5.03 Typical Stone Alternative Cross Section

Figure 5.04 Planning Set Cost and Output

Figure 5.05 Planning Set Incremental Cost and Output

Figure 5.06 Priority Areas for Oyster Restoration, as Recommended by the 

NCORSC Northern Workgroup (Includes Old House Channel)

Figure 5.07 Volunteers Placing Oyster Shells in NC Waters to Create Reef

Figure 6.01 Potential Staging Area Dare County

Figure 6.02 Potential Staging Area Hyde County

Figure 6.03 Estimated Project Costs

Appendices

APPENDIX A Scoping Comments and Responses

APPENDIX B Sponsor Study Request

APPENDIX C Design & Engineering 

APPENDIX D Cost Engineering

APPENDIX E Geotechnical Engineering

APPENDIX F Old House Channel Bathymetric and Side Scan 

Survey

APPENDIX G ERDC Surface Sediment Analysis Report

APPENDIX H SHPO Letter of Concurrence

APPENDIX I Attribute Table of State Oyster Sanctuaries

APPENDIX J Real Estate
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List of Acronyms

AAHU Average Annual Habitat Unit

AFP Associate Filtered Press

AIWW Atlantic Intracoastal Waterway

APES Albemarle-Pamlico Estuary System

APNEP Albemarle Pamlico National Estuary Program

CAA Clean Air Act

CAP Continuing Authorities Program

CFR Code of Federal Regulations

CHPP Coastal Habitat Protection Plan

DMMP Dredged Material Management Plan

DPR Detailed Project Report

EA Environmental Assessment

EBA Environmental Benefits Assessment

EFH Essential Fish Habitat

EPA U.S. Environmental Protection Agency

ER Engineering Regulation

ERDC US Army Corps of Engineers – Engineering 

Research and Development Center

FONSI Finding of No Significant Impact

FMC Fishery Management Councils

HAPC Habitat Areas of Particular Concern

HEP Habitat Evaluation Procedure

HSI Habitat Suitability Index

HTRW Hazardous, Toxic, and Radioactive Waste

HU Habitat Unit

IPCC Intergovernmental Panel on Climate Change

IWR-Plan Institute for Water Resources, costeffectiveness/incremental cost analysis 

software

LERRD Land, Easements, Rights-of-Way, Relocation, and 

Disposal Areas

MHW Mean High Water

MHHW Mean Higher High Water

MLW Mean Low Water

MLLW Mean Lower Low Water

MSFCMA Magnuson-Stevens Fishery Conservation and 

Management Act

MSL Mean Sea Level

NCCF North Carolina Coastal Federation

NCDCM North Carolina Division of Coastal Management
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NCDENR North Carolina Department of Environment and 

Natural Resources

NCDMF North Carolina Division of Marine Fisheries

NCDOT North Carolina Department of Transportation

NCDWQ North Carolina Division of Water Quality

NCORSC North Carolina Oyster Restoration Steering

Committee

NED National Economic Development

NEPA National Environmental Policy Act

NEPCC National Estuary Program Coastal Report

NER National Ecosystem Restoration

NEPCCR National Estuary Program Coastal Condition Report

NFS Non-Federal Sponsor

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration

NPS National Park Service

NRC National Research Council

OMRR&R Operation, Maintenance, Repair, Replacement, and 

Rehabilitation

ORM Organic Rich Mud

O&M Operation and Maintenance

PAHs Polynuclear Aromatic Hydrocarbons

PPA Project Partnership Agreement

PCBs Polychlorinated Biphenyls

PED Planning, Engineering, and Design

PL Public Law

PNA Primary Nursery Area

POC Point of Contact

PPA Project Partnership Agreement

PPR Preliminary Policy Report

RSM Regional Sediment Management

SA NC water classification: “Classified for commercial 

shellfish harvesting”

SAV Submerged Aquatic Vegetation

SB NC water classification: “Classified for primary 

recreation”

SC NC water classification: “Classified for aquatic life 

propagation/protection and secondary 

recreation”

SAD South Atlantic Division, US Army Corps of 

Engineers

SIP State Implementation Plan

SOW Scope of Work
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USACE US Army Corps of Engineers

USACE-ERDC US Army Corps of Engineers – Engineering 

Research and Development Center

USACE P&G US Army Corps of Engineers Principles and 

Guidelines

US EPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service

WRC/NCWRC North Carolina Wildlife Resources Commission

WRDA Water Resources Development Act
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Draft

Section 204 Feasibility Report & EA

Manteo, Old House Channel, NC - Beneficial Use of Dredged 

Material Restoration Project

Executive Summary

This Section 204 Feasibility Report and Environmental Assessment (EA) 

presents the findings regarding the Manteo, Old House Channel, NC - Beneficial 

Use of Dredged Material for Oyster Reef Restoration Project, and documents the 

plan formulation process and potential environmental effects associated with the 

implementation of oyster reef restoration alternatives for the proposed site. The 

geographic scope of this study consists of an approximately 17-square-mile 

Project Study Area, the center of which is located in northeastern North Carolina, 

within Pamlico Sound and Dare County, approximately 13 miles south-southeast 

of Manteo, NC and 4.5 miles southwest of Oregon Inlet. Range 2 of Old House 

Channel runs through the middle of this area, and is part of the Manteo 

(Shallowbag Bay) Federal Navigation Project.

The overall goal of the Manteo, Old House Channel, NC Section 204 study is to 

improve oyster reef habitat that has been in historical decline in Pamlico Sound, 

through the beneficial use of dredged material from Old House Channel. In 2008 

the State of North Carolina responded to indicators signaling potential further 

decline of the Pamlico system and its oyster populations by enacting new State 

coastal stormwater rules to protect and improve water quality. The State also 

requested the USACE (Corps) to investigate opportunities for oyster restoration 

in the Pamlico system, indicating a willingness and financial capability to execute 

a project partnership agreement (PPA) should a detailed project report be 

approved. This project would contribute to the State’s oyster restoration goals in 

the northern Pamlico Sound in conjunction with the Corp’s operational dredging 

and disposal needs for Old House Channel (Range 2).

This report summarizes baseline existing conditions in the study area, as well as 

projected future conditions without the project. It also develops and discusses 

potential solutions as a guide to Federal and non-Federal involvement in the 

restoration project. This report provides a description and discussion of the likely 

array of alternative plans, including their benefits, costs, and environmental 

effects and outputs. This report also identifies, evaluates, and recommends a 

solution (the Tentatively-Selected Plan) that best meets the planning objectives 

of oyster habitat restoration and beneficial uses of dredged material within the 

study area.
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The Tentatively-Selected Plan (oyster reef construction) involves use of dredged 

material from maintenance dredging of Old House Channel to restore habitat by 

building submerged sand islands to be topped with cultch for oyster reef 

restoration. Containment of sand for the submerged islands would be 

accomplished using stone. Based on the cost effectiveness/incremental cost 

analysis of these options, the best-buyplan would be a complex of four stone 

containment structures, each enclosing a 5.07-acre reef. However, the best-buy 

plan has an estimated cost of $8,393,000 and would exceed the federal costshare limit of the Section 204 authority of $5,000,000. The Tentatively-Selected 

Plan (TSP) is therefore the most cost-effective alternative with a federal cost 

within the cost-share limit. The TSP is composed of three stone containment 

structures, each enclosing a 5.07-acre reef. The Total Project Cost for 

implementation of the TSP would be $7,217,000. The Federal cost-share is

$4,850,000 (includes 100% of feasibility costs). The non-Federal cost of the 

TSP would be $2,367,000, which is 35% of the total Design & Implementation 

phase costs. The period of analysis used to compute costs is 50 years with a 

FY12 federal interest rate of 4.0%. This Tentatively-Selected plan would provide 

restoration benefits of 32.3 average annual habitat units (AAHU) at an average 

annual cost of $329,429, which results in an average annual cost per AAHU of 

$10,199. The non-Federal sponsor fully supports the Tentatively-Selected Plan.
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1.0 STUDY AUTHORITY AND BACKGROUND

Continuing Authorities Program (CAP) Section 204 of the Water Resources 

Development Act of 1992 (WRDA 1992) – Beneficial Uses of Dredged Material, 

as amended by Section 2037 of WRDA 2007. 

According to Engineering Regulation (ER) 1105-2-100, paragraph F3.a, “the 

purpose of CAP is to implement projects of limited size, cost, scope, & 

complexity”. The Section 204 CAP authority authorizes the U.S. Army Corps of 

Engineers to carry out projects for the protection, restoration, and creation of 

aquatic and ecologically related habitats, including wetlands, in connection with 

dredging for construction, operation, or maintenance of an authorized navigation 

project. The Federal share of the costs for any one project may not exceed 

$5,000,000. There is an annual appropriation limit of $30,000,000 nationwide.

Cost sharing for Section 204 projects is based on the increase in cost of the 

ecosystem restoration project compared to the cost of disposal of dredged 

material without the ecosystem restoration project. Only the increased cost 

above the cost of the disposal option that would have been implemented without 

ecosystem restoration (referred to as the Base Plan) is cost shared. The detailed 

project feasibility study is funded completely by the Federal government. If the 

proposal is approved for implementation, the non-Federal sponsor 

responsibilities in accordance with the project partnership agreement (PPA) 

include: (a) provide all lands, easements, rights of way, and dredged material 

disposal areas and perform all necessary relocations (LERRD) necessary for the 

project; (b) participate in the project coordination team; (c) pay any cash 

contribution during construction necessary so that the total contribution of the 

non-Federal interest including value of LERRD will be 35 percent of the cost of 

the project; (c) pay 100 percent of the operation, maintenance, replacement, 

repair, and rehabilitation (OMRR&R) cost of the beneficial use project. The nonFederal sponsor shall receive credit for the value of in-kind contributions against 

the requirement for additional cash to bring the non-Federal share of the project 

to 35 percent in accordance with provisions of SEC.2003 of WRDA 2007. Total 

project costs are defined as the incremental amount above the costs for the 

existing dredging plan “base plan” (ER 1105-2-100 Appendix F, pg.F-37).

In July of 2008, the U.S. Army Corps of Engineers received a letter from the 

North Carolina Department of Natural Resources, Division of Water Resources, 

requesting the Corps to investigate opportunities for oyster restoration at Old 

House Channel, Manteo (Shallowbag) Bay, NC under the 204 authority. The 

letter also indicated a willingness and financial capability to execute a project 

partnership agreement (PPA) should a detailed project report be approved. In 

response to this letter, a Preliminary Policy Report (PPR) for this study was 

submitted to USACE SAD in July of 2008 and approved by SAD in August of 
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2008. The approved PPR established federal interest in further study of a 

Section 204 for Manteo, Old House Channel, NC. The results of this study are 

presented in this Detailed Project Report. 

2.0 STUDY GOAL, LOCATION, AND SCOPE

2.1 Study Goal

This study results from both a recognized decline of oyster reef habitat in coastal 

North Carolina and State efforts for oyster restoration in Pamlico Sound, NC 

(Street, 2005). The planning study goal is to recommend a cost-effective and 

environmentally-sound dredged material disposal option that will contribute to the 

State of North Carolina’s oyster restoration goals in the northern Pamlico Sound 

in conjunction with the Corp’s operational dredging and disposal needs for Old 

House Channel (Range 2).

2.2 Study Area Location

The Study Area is the approximately 17 square-mile area identified in Figure 

2.01, which was chosen based on its vicinity to State oyster restoration efforts, 

and identified dredged material disposal needs from Old House Channel (Range 

2). The center of the Study Area is approximately 4.5 miles southwest of Oregon 

Inlet. Range 2 of Old House Channel runs through the middle of this area. The 

County impacted is Dare County, NC. The larger surrounding vicinity is Pamlico 

Sound, NC. A geographic representation of the Study Area within the larger area 

of the Sound is shown in Figure 2.02.
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Figure 2.01. Project Study Area Note: Positions are NC Sate Plane feet. NAD 1983.
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Figure 2.02. Project Study Area (Yellow Box) in Relation to Surrounding Project Vicinity
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2.3 Study Scope & Process

In accordance with the preliminary policy report (PPR) approved by SAD in 

August 2008, this study investigates the beneficial use of dredged material from 

Old House Channel (Range 2) for oyster reef restoration. The report considers 

an array of alternatives, in addition to a No-Action alternative. 

This report documents the study results for the proposed Section 204 beneficial 

use of dredged material project at Manteo, Old House Channel, NC in the 3rd

Congressional District, within Dare County, NC. The study has been conducted 

in accordance with feasibility study guidelines contained in the Planning 

Guidance Notebook (ER 1105-2-100) and other applicable USACE regulations 

and guidance.

The purpose of this Detailed Project Report (DPR) and Environmental 

Assessment (EA) Study is to:

• Discuss the identified problems, opportunities, and constraints

• Document the project objectives

• Describe existing and potential future conditions

• Identify alternative means to achieve the project objectives

• Analyze the feasibility, costs, benefits, and effects of alternatives

• Recommend an alternative that best meets project objectives in a costeffective manner

This study will complete the plan formulation process, including the selection of a 

recommended plan. The level of detail shall be appropriate for the scope and 

complexity of the CAP study, and sufficient to proceed into detailed design and 

implementation.

3.0 PRIOR STUDIES, REPORTS, AND EXISTING PROJECTS

3.1 Prior Studies and Reports

For the assessment of existing conditions and the forecasting of future without 

project conditions, the study team reviewed the following reports as part of this 

study:

Engineer District, Wilmington, NC, “Supplement No. 1, Manteo 

(Shallowbag) Bay, North Carolina, Design Memorandum 2, General Design 

Memorandum Phase II,” September 1983.
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The report gives a project description and summary for the navigation project in 

Manteo (Shallowbag) Bay, which includes Old House Channel. Information

includes channel width/depth, and dredging cycle.

Manteo Shallowbag Bay Disposal Areas Summary Document. USACEWilmington District. 1997.

This summary gives status updates (as of 1997) for the disposal areas of the 

Manteo Shallowbag Bay navigation project, including Wells & Parnell Islands 

within the Manteo 204 study area.

Oyster Restoration and Protection Plan for North Carolina: A Blueprint For 

Action - Second Edition 2008 – 2012

This report, published by the North Carolina Coastal Federation (NCCF) in 

cooperation with various governmental, non-profit, and private organizations, is a 

five-year blueprint that outlines a series of goals, objectives, and specific actions 

that would need to be implemented to protect and restore oyster habitat and 

shellfish waters. This report also establishes priority areas for oyster restoration 

in Pamlico Sound. Now that a significant number of the objectives of the first 

action plan have been realized and new opportunities and challenges have 

presented themselves, a second edition of the Blueprint has been developed to 

establish a joint vision among the stakeholders for the next five years. The 

following goals, objectives and action items represent the second five year cycle 

of the Blueprint. 1) To restore and protect North Carolina’s native oyster 

populations and habitat in an effort to restore North Carolina estuaries to robust, 

diverse, & resilient ecosystems; 2) To build broad public awareness & support for 

the value of oyster restoration, estuarine conservation and sustainable fisheries, 

and 3) To establish and work with a comprehensive coalition to build and 

maintain significant, demonstrable and meaningful progress towards oyster 

restoration in the next five years.

The following summary of the NCDMF Sanctuary Program is quoted from 

(Eggelston et al. 2011) "The North Carolina Division of Marine Fisheries began 

the creation of a network of no-take oyster broodstock reserves in 1996 in an 

effort to enhance the oyster metapopulation in Pamlico Sound. A secondary goal 

was to create oyster reefs that would serve as EFH, and support recreational and 

commercial fisheries (NCDMF Stock Status Report 2010). These oyster 

restoration efforts were accelerated greatly in 2009-2010 with funding via the 

American Reinvestment and Recovery Act (ARRA), which created 17 ha of 

oyster reefs in nine months (Pelle Holmlund, NC DMF, personal communication), 

compared to the previous 49 ha that had been created since 1996. With ARRA 

funding, new mounds were created during winter of 2009 and early spring 2010 

with the addition of 191 and 144 mounds at Clam Shoal and Crab Hole, 

respectively (NCDMF 2010). As of 2011, a total of 10 brood stock sanctuaries 

have been established with footprints ranging in size from 1.86 ha to 19.30 ha 
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and with each reserve containing high-relief (2m) limestone marl mounds (NC 

DMF). Limestone riprap material used to create oyster broodstock reserves were 

colonized by oysters via natural settlement, and oyster densities have generally 

increased in these reserves 5 to 15 fold since 2006 (Puckett & Eggleston, in 

review).

Street, M.W., A.S. Deaton, W.S. Chappell, and P.D. Mooreside. 2005. North

Carolina Coastal Habitat Protection Plan. North Carolina Department of 

Environment and Natural Resources, Division of Marine Fisheries, 

Morehead City, NC. 656pp.

In accordance with the North Carolina Fisheries Reform Act of 1997, the 

Coastal Habitat Protection Plan (CHPP) was developed to protect habitats, 

including wetlands, spawning areas, threatened and endangered species 

habitat, primary and secondary nursery areas, shellfish beds, submerged 

aquatic vegetation, and Outstanding Resource Waters. The CHPP was written 

to “1) Document the ecological role and function of aquatic habitats for coastal 

fisheries. 2) Provide status and trends information on the quality and quantity of 

coastal fish habitat. 3) Describe and document threats to coastal fish habitat, 

including threats from both human activities and natural events. 4) Describe the 

current rules concerning each habitat. 5) Identify management needs. 6) Develop 

options for management action using the above information.”

U.S. Army Corps of Engineers – Wilmington District, South Atlantic 

Division. 2009. Draft Interim Feasibility Report and Environmental Impact 

Statement for the Neuse River Basin. 

This ongoing study is also investigating construction of high relief subtidal reefs 

in the Neuse River, a component of the Albemarle Pamlico National Estuary. 

This report contains useful information on oyster habitat requirements and 

potential construction methods, applicable to Old House Channel Section 204 

study. 

Oyster Settlement and Reef Mapping in Pamlico Sound (July 2009) 

Ballance, E., Eggleston, D., Plaia, G., and Puckett, B. North Carolina 

Fishery Resource Grant Project. 

This report, the result of a NC Fishery Resource Grant Project, discusses the 

results of a large-scale field program whose overall goal was to provide data to 

aid the State of North Carolina in locating oyster broodstock sanctuaries in 

Pamlico Sound. This study identified live natural reefs in the project area. These 

reefs were mapped during Corps sidescan surveys and field verified by NCDMF 

as containing oysters of legal size for harvest. These sites are in open shellfish 

waters and subject to harvest.
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3.2 Existing Projects

Manteo (Shallowbag) Bay Navigation Project. Maintained by the U.S. Army 

Corps of Engineers, the Manteo (Shallowbag) Bay Project was initially authorized 

on June 25, 1910, with subsequent modifications to the authorization in 1940 and 

1950. The project is located along the Outer Banks portion of Dare County, 

North Carolina, between Oregon Inlet, Roanoke Island, and Albemarle Sound. 

The navigation project provides for a channel 14 feet deep and 400 feet wide 

from the Atlantic Ocean through Oregon Inlet with connecting 12 foot channels, 

100 feet wide, to Pamlico Sound, Wanchese, and a 10 feet deep and 100 feet 

wide, connecting the Manteo-Oregon Inlet Channel with Albemarle Sound. The 

project is maintained in three general areas: a) Interior Channels (which includes 

Old House Channel), b) Spit portion of Ocean bar, and c) Outer Ocean Bar. 

State of North Carolina’s Oyster Sanctuary Program. The State has ten 

sanctuaries in the Albemarle-Pamlico Estuary System (APES), with one 

additional sanctuary in the planning stages (NCDMF website, 2009). The 

following two are within 0.6 and 2.3 miles of the Manteo 204 project study area, 

respectively (figure 3.01). 

Crab Hole Oyster Sanctuary. Established in 2003, this sanctuary is composed 

of 16,170 tons of riprap and covers approximately 30.5 acres. Its location is 

roughly 0.6 miles south-west of the project study area. Partners include the NC 

Division of Marine Fisheries, Division of Coastal Management, N.C. Department 

of Transportation, and The Nature Conservancy. 

Croatan Sound Oyster Sanctuary. Established in 1996, this sanctuary is 

composed of 1,800 tons of riprap, 4,000 bushels of oyster shells, 2,640 bushels 

of surf clam shells, and 4,000 bushels of limestone marl. The sanctuary covers 

approximately 7.7 acres and is located roughly 2.3 miles north of the project 

study area. Partners include the NC Division of Marine Fisheries and NOAA’s 

National Marine Fisheries Service.

Festival Park, Roanoke Island, NC. Aquatic Habitat Restoration and 

Protection Project. This USACE ecosystem restoration project located in the 

vicinity of the potential project area included subtidal oyster reef construction. 

Constructed in 2004, this estuarine restoration project restored 5 acres of marsh, 

seagrass, oysters, and forest. This included the construction of a rock sill for 

erosion protection and structure comprised of 1,500 cubic yards of marl and 

10,000 bushels of oysters along 1,330 feet of eroded shoreline. Partners 

included the NC Coastal Federation, NC Forest Service, US Fish and Wildlife 

Service, NC State University, NC Divisions of Water Resources and Marine 

Fisheries, and The Nature Conservancy.

Wanchese Marsh Creation and Protection, NC. Section 204 Draft Feasibility 

Report and Environmental Assessment (1999) USACE-Wilmington District.
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This project includes creating and protecting marsh habitat at Wanchese Harbor 

adjacent to the channel from Oregon Inlet, Dare County, NC. Approximately 8 

acres of estuarine creek and marsh area and a containment dike were 

constructed immediately north of the harbor area. Dredged material from the 

maintenance dredging of the navigation channel was pumped behind the dike, 

supplemented by dry trucked sand and graded to create the marsh and 

estuarine creek habitat .. This successfully completed ecosystem restoration 

project located in the vicinity of the potential project area included subtidal oyster 

reef construction and could provide a nearby reference site. Partners included 

the, NC Divisions of Water Resources and Marine Fisheries
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Manteo, Old House Channel, NC Section 204 Project

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Figure 3.01. Map Showing Proximity between Nearby NCDMF Oyster Sanctuaries and the 

Project Study Area
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4.0 EXISTING AND PROJECTED FUTURE – WITHOUT PROJECT 

CONDITIONS

Each section will identify the existing conditions of the project area including the 

greater surrounding area that is within Pamlico Sound, as well as a future-without 

project conditions analysis based on the best available data regarding the 

projected conditions of the resources without the proposed project. Futurewithout project conditions analysis assumes that conditions will continue to trend 

in the direction that is indicated within studies and data available at this time. 

References to future conditions assume a fifty year projected timeline. 

4.1 General Environmental Setting

Pamlico Sound is the second largest sound in the United States and the largest 

sound on North Carolina’s East Coast. It is separated from the Atlantic Ocean by 

the narrow barrier islands of the Outer Banks. It is part of an interconnected set 

of estuaries that make up Albemarle Pamlico National Estuary, The AlbemarlePamlico system represents one of North Carolina’s key resource bases for 

commercial fishing, recreational fishing, and tourism (US EPA National Coastal 

Conditions Report III, 2008 website):

http://www.epa.gov/owow/oceans/nccr3/downloads.html

The Albemarle Pamlico National Estuary is fed by several major river basins: 

Pasquotank, Chowan, Roanoke, Tar-Pamlico, Neuse, and White Oak. It also 

includes seven sounds: Currituck, Albemarle, Roanoke, Croatan, Pamlico, Core 

and Bogue. Pamlico Sound extends 80 miles from Roanoke Island to Cedar 

Island and is about 15–30 miles wide reaching depths up to 26 feet. It is 

connected to the Tar-Pamlico and Neuse-Trent rivers on the west side of the 

sound, and inlets provide resources from the ocean primarily through Ocracoke, 

Hatteras and Oregon Inlets (Figure 4.01).

 
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The project vicinity includes the northern Pamlico Sound, specifically sub-basins 

03-01-56, 03-01-51, and 03-01-55. The Study Area is the 17 square-mile area 

located within the project vicinity (Figure 2.01). As stated in section 2.2, the

Study Area was chosen based on proximity to both State oyster restoration 

efforts, and dredge material disposal needs at Old House Channel (Range 2). 

4.1.1 Climate

The Gulf Stream, which runs up the coast from the tropics at four miles per hour, 

moderates temperatures along the coast. Near Cape Hatteras the Gulf Stream, 

usually 12 to 15 miles from the coast, begins to move further offshore as it heads 

towards the British Isles. Coastal North Carolina enjoys moderate climates that 

are warmer than inland counterparts, with temperatures ranging typically from 50 

degrees on average in January to 80 degrees on average in July. This is largely 

attributed to the consistently warmer waters of the Gulf Stream. However, the 

cold Labrador Current passes between the Gulf Stream and the North Carolina 

coast, often offsetting much of the warming effect the Gulf Stream might have on 

coastal temperatures. The meeting of the two opposing currents provides a high 

variability that often produces rough weather in the area.

Figure 4.01. General Environmental Setting
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http://www.nc-climate.ncsu.edu/climate/ncclimate.html

Future-without project conditions. Climate along the coastline of the project 

area is dynamic and highly dependent on seasonal variations. Climate change is 

expected to have a localized impact on the project area by potentially increasing 

average water temperatures. An increase in average water temperaturemay 

have a direct impact on the average seasonal air temperatures of the greater 

Pamlico area. However, future conditions are not anticipated to exceed the 

tolerance levels of major resources over the period of analysis and should not 

have a significant impact on the future conditional analysis of other resources 

within Pamlico Sound or the immediate project area.

4.1.2 Tides, Currents and Sea Level Rise

The nearest tide gauge to the Manteo, Old House Channel Project Study Area is 

located at the Oregon Inlet Fishing Center which lies north of the proposed 

project area. This site was used as a reference point for this project. Table 4.01 

gives pertinent tide range data for Oregon Inlet and Pamlico Sound. It is 

expected that lunar tides in the project area would be comparable to those 

exhibited at the Oregon Inlet Marina gauge.

http://tidesandcurrents.noaa.gov/data_menu.shtml?stn=8652648%20

Old%20House%20Channel,%20NC&type=Bench%20Mark%20Data

%20Sheets

Table 4.01. Pertinent Tide Data

PERTINENT TIDE DATA

Tide Level m.l.l.w (ft) m.s.l. (ft)

Mean Higher High Water ( m.h.h.w.) 0.90 + 0.44

Mean High Water (m.h.w.) 0.77 + 0.31

Mean Low Water (m.l.w.) 0.13 - 0.34

Mean Lower Low Water (m.l.l.w.) 0.00 - 0.46

The lunar tidal range between m.h.h.w. and m.l.l.w. is only 0.90 feet (Table 4.01). 

The Pamlico Sound wind and long fetch length cause wind to have a greater 

impact on tide levels than normal lunar tide cycles. Depending on the wind 

direction, on any given day the tides can be higher or lower than normal. The 

barrier islands of the Outer Banks also play a part in attenuating the tidal pull 

within Pamlico Sound. Currents tend to be stronger with closer proximity to 

Oregon Inlet (Appendix I). Although the project area is several miles from the 

inlet with typically lower velocity current, the area is dynamic with impacts from 

frequent storms. Seven named tropical storms have made direct landfall on the 

*Mean Sea Levelm.l.l.w. is referenced to NAVD 88.
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area in the last ten years, in addition to numerous nor’easters (www.ncclimate.ncsu.edu). 

Future-without project conditions. Since the project site is in relatively close 

proximity to the tide data collection site at Oregon Inlet Marina, sea level changes 

are estimated based upon this tide station, as presented in Figure 4.02. Based 

on the monthly mean sea level data from 1977 to 2006, the mean sea level trend 

is 2.82 millimeters/year, with a 95% confidence interval of +/- 1.76 mm/yr. This is 

equivalent to a change of about 0.47 feet in 50 years. The data set is a shorter 

than preferred tidal record, but trend is similar to other North Carolina coast sea 

level trends with longer tide records (Beaufort, NC – 2.57 mm/yr; Southport, NC –

2.08 mm/yr). 

http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8652587

Oregon Inlet Marina, NC

 

 Figure 4.02. Plot of Tide Levels Oregon Inlet Marina, NC - NOAA Website

The Intergovernmental Panel on Climate Change (IPCC) projects accelerated 

global warming which leads to accelerated sea level rise. USACE guidance (EC 

1165-2-211) requires consideration of these various accelerated sea level rise 

scenarios for water resources projects [Note: USACE guidance cited has 

expired, but alternative guidance has not yet been issued]. The sea level rise 

global scenarios evaluated include: 1) the historical rate of sea level rise – from 
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tide data above, 2) projections using the updated National Research Council 

(NRC) curve 1 – representing global eustatic sea-level rise of 0.5 meters (1.64 ft)

in 125 years, and 3) projections based on NRC curve 3 – representing sea level 

rise of 1.5 meters (4.92 feet) in 125 years. 

Figure 4.03. Plot of Sea-Level-Rise 50-Year Projections based upon Historical and Accelerated 

Rates

The NRC curves 1 and 3 in Figure 4.03 above have been adjusted to account for 

local subsidence rates for the Oregon Inlet area. Curves 1 and 3 project an 

accelerated sea level rise of 0.87 feet and 2.2 feet over a period of 50 years, 

respectively. Potential sea level rise impacts on the preferred alternative are 

discussed in Section 7.1.2.

4.1.3 Water Quality

The North Carolina Department of Environment and Natural Resources 

(NCDENR) classifies the waters from Albemarle Sound to Pamlico Sound as SA. 

SA waters are tidal salt waters acceptable for shell fishing for market purposes; 

they are also protected for all class SC and Class SB uses. SC and SB uses

include aquatic life propagation and survival, wildlife, as well as recreational 

activities including fishing and boating and other uses involving human body 

contact with water. 

0.00

0.50

1.00

1.50

2.00

2.50

2014201820222026203020342038204220462050205420582062

SLR Projection in FT

Year

Oregon Inlet SLR Projections

Eustatic SLR Projection - Modified NRC Curve 3

Eustatic SLR Projection - Modified NRC Curve 1

Historical SLR Projection
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The water quality of the open water of Pamlico Sound, including the project area 

located near Oregon Inlet, is considered good SA waters. In the Pasquotank 

Subbasins surrounding the project area, a small percentage of SA waters are 

considered impaired for shellfish harvesting. Out of approximately 395,230 acres 

of shellfish harvesting only 6,471 acres are impaired (1.64%). There are no 

closed or impaired shell fishing areas in the immediate project vicinity. The 

nearest closed shell fishing areas are located in Stumpy Point Bay, a small area 

at the Oregon Inlet Marina, and the southern portion of Wanchese – all of which 

are over three miles away from the project site. 

http://h2o.enr.state.nc.us/basinwide/Pasquotank2007.htm

Water quality monitoring data collected periodically from the nearby sampling 

station at the Oregon Inlet Fishing Center collected by the North Carolina 

Shellfish Sanitation and Recreational Water Quality Section between 2006 and 

2011, included both salinity and temperature data as. Water salinity in the 

project vicinity averages about 18 ppt. As an indicator species for this study, C. 

virginica (eastern oyster) has a salinity range in their geographical region from 

about 10 ppt to 28-30 ppt. (Gunter and Geyer 1955, Gultsoff 1964, Loosanoff 

1965, Eleuterius 1977, Wilson et al. 2005). Optimal salinities range from 10 to 20 

ppt (Butler 1954, Eleuterius 1977). Temperature in the project vicinity averages 

about 63 degrees F. Temperature and latitude influences oyster growth, 

development, reproduction, and feeding activity (Shumway 1996), and 

temperature is a primary environmental variable affecting the development of 

larvae (Loosanoff and Davis 1963, Loosanoff 1965). The eastern oyster can 

tolerate a wide range of temperatures; as low as -1.7oC (28.9 F) in New England 

to 36oC (96.8 F) in Gulf of Mexico (Sellers et al. 1984). Optimal temperatures for 

growth, reproduction, and survival of adults (Cake 1983) and larvae range from 

20oC (68 F) to 30oC (86F) (Loosanoff and Davis 1963). 

Few direct dischargers of toxic pollution to the sound are known, indicating that 

nonpoint sources of pollution are probably more significant. Potential nonpoint 

sources of pollutants include marinas, river basin discharge, solid and hazardous 

waste sites, and farming runoff. Fecal coli form bacteria continues to be the 

primary problem parameter. Seventeen marinas exist within the drainage basin, 

with the largest concentrations occurring at Hatteras, Ocracoke, and in Rose. 

The closest marinas to the project site are the Oregon Inlet Fishing Center and 

Wanchese Harbor located over 4 miles and 5 miles away, respectively.

Future-without project conditions. Water quality in the Pamlico Sound will 

continue to be stressed by burgeoning population, farming, and increased 

tourism and potentially increasing point and nonpoint sources of pollutants. The 

National Estuary Program Coastal Condition Report (NEPCCR, 2007) has 

indicated that there have been some long term patterns that have developed in 

the past forty years that include both positive and negative indicators. 

Improvements include increased dissolved oxygen levels and decreased levels 
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Manteo, Old House Channel, NC Section 204 Project

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of suspended solids. Negatively, increased levels of Chlorophyll a could indicate 

a trend toward eutrophication. The loss of oysters in the Pamlico Sound may 

have contributed to this trend (NEPCCR, 2007). Efforts by the state to develop a 

statewide oyster sanctuary program have the potential to reduce this trend as 

oysters provide ecosystem services such as water filtration which can reduce 

eutrophication. The overall conclusion of the Coastal Condition report indicated 

that the Pamlico system is in good health but that factors exist that may signal 

the potential for declining health of the system (NEPCCR, 2007). The year 

following the release of the 2007 NEPCCR, the State of North Carolina 

implemented new requirements mandating that the state’s 20 coastal counties

take steps to reduce pollutant-laden stormwater runoff — a major contributor to 

water quality degradation. In part, the newer rules require buffers and setbacks,

address built-upon coverage, and broaden the array of on-site stormwater control 

and treatment methods for new or redevelopment projects. To view complete 

regulatory details, go to the NC Division of Water Quality website at:

http://h2o.ehnr.state.nc.us/su/coastal.htm

These rules are in part designed to offset impacts from continued growth in 

coastal development.

4.1.4 Current Land Use in Project Area

The Project Study Area is located in open-water with no land within several 

miles, excluding the man-made dredged disposal islands. However, the 

drainage sub-basins encompassing the greater project vicinity have an overall 

low population density with seasonal peaks during the summer tourist season. 

The numbers of individuals that move into the area remain low, limiting the 

impact that urban development has on the area. Of the basin's total land area, 

the Albemarle-Pamlico National Estuary program estimates that forests cover 

33%, wetlands, swamps, and marshes cover 28%, agriculture comprises 25%, 

and urban land accounts for under 1 percent. 

http://h2o.enr.state.nc.us/nep/tarpamlico_river_basin.htm

Future-without project conditions. Population pressures may stay low due to 

absence of large cities and the existence of large acreages of protected land 

surrounding Pamlico Sound. Future conditions are expected to remain relatively 

stable with minor fluctuations year to year and an overall minor increase in 

population pressures that should not result in any significant changes to the 

current condition of Pamlico Sound that would alter the overall health of the 

system (NEPCCR, 2007, pages 202-211).
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4.2 Biotic Communities

4.2.1 Aquatic Habitats

Existing habitats include open water areas comprised primarily of sandy bottom, 

infrequent scattered oyster reefs, and sparse patches of seagrass. Resources 

are variable in Pamlico Sound and range from limited resources occurring in 

frequently dredged channel bottoms to complex and diverse communities 

occurring in stable grass beds. Table 4.02, based on survey data collected by 

the USACE between July and September, 2009 (Appendix 1 Survey SOW), 

indicates submerged aquatic vegetation (SAV), oyster, and island resources 

within the Study Area. 

The State of North Carolina defines primary nursery areas as those areas in the 

estuarine system where initial post-larval development takes place. These areas 

are identified and monitored by annual trawl sampling by the North Carolina 

Division of Marine Fisheries (NCDMF). No Primary Nursery is found in the Study 

Area. The nearest nursery area is upper Broad Creek located over 7 miles away.

Resource Coverage in Study Area

Material Type Area (sq mi) Coverage (%)

SAV 2.26 13

High backscatter/shells 0.2 1

Fine Sand 14.79 86

Project Area Totals: 17.25 100

Table 4.02. Breakdown of Resource Coverage in Project Study Area based on 

Detailed Side-Scan Survey
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Figure 4.04. Resources Mapped within Project Study Area along with Existing Disposal 

Islands (Sonar Survey Mapping, Duck Research Center, Side-Scan Survey – July-Sept. 2009).

 
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4.2.1.1 Submerged Aquatic Vegetation

SAV stabilizes shorelines by binding underwater sediment with their roots and 

rhizomes in shallow offshore regions, trapping suspended sediment, and baffling 

waves and currents. In addition, SAV modifies sediment quantity and quality. In 

doing this, SAV decreases underwater erosion and improves shoreline structure. 

Because of this, SAV is a critical part of the structural integrity of North Carolina’s 

near shore environment. SAV also functions as important habitat for many fish 

and shellfish, including some of the most valuable commercial and recreational 

species. SAV is home to a diverse group of flora and fauna and is a valuable part 

of a healthy ecosystem (Street, Deaton, Chappell, & Mooreside, 2005). 

Albemarle Pamlico National Estuary Program (APNEP) reports on submerged 

aquatic vegetation in the Albemarle-Pamlico Estuarine system indicate that the 

most productive SAV habitats are in the shallow saline waters on the eastern 

side of Pamlico Sound. Eelgrass, shoal grass, and widgeon grass are common 

and often dominate these environments. Eighty percent (80%) of the SAV is in 

southern and eastern Pamlico Sound. Western Pamlico Sound demonstrated a 

lack of SAV when compared with the eastern portion of the sound (APNEP). It is 

estimated that there are 200,000 acres of SAV in North Carolina, about as much 

habitat as there is salt marsh, and SAV comprises about 8.5 percent of the total 

estuarine bottom in the state (Street et al., 2005). 

http://www.cop.noaa.gov/stressors/climatechange/current/slr/habitats.html

A sidescan and multibeam survey was conducted in late summer of 2009 and 

indicated that 2.26 square-miles of SAV were found within the 17.25 square-mile

survey area (i.e., 13% coverage) (see Table 4.02 and Figure 4.04 above). 

Future-without project conditions. Based on current trends and conditions it is 

anticipated that future conditions should continue to improve with natural 

fluctuations occurring during severe weather events such as droughts and 

hurricanes (NEPCC, 2007). Stronger regulations have promoted the reduction in 

nutrients in waters supporting SAV and a decrease in suspended solids and 

sediments, as well as dissolved solids that have trended downward since the late 

1980’s (Street et al., 2005). A continued downward trend of sediments and 

nutrients is expected to continue promoting continued improvements in water 

clarity, which creates more favorable conditions for many historic SAV beds. The 

effect of climate change on this habitat includes sea level rise that may increase 

sedimentation and water temperature, possibly changing species interactions. 

However, the degree of change that this variable would have on the habitat is 

unknown at this time.

http://www.cop.noaa.gov/stressors/climatechange/current/slr/habitats.html
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4.2.1.2 Shell Bottoms

The North Carolina Coastal Habitat Protection Plan (CHPP) defines shell bottom 

habitat as estuarine intertidal or sub tidal bottom composed of shell surface 

concentrations of living or dead oysters, hard clams, or other shell fish with 

oyster reefs predominating. North Carolina managers consider this habitat critical 

to fisheries production. Oysters can tolerate extremes in salinity, temperature, 

turbidity, and low dissolved oxygen, but spawning success requires optimal water 

quality and good currents for dispersal. Primary producers on shell bottom 

include algae and organic films of bacteria and fungi which provide food for 

resident secondary communities of crabs, barnacles, clams, mussels, anemones, 

polychaetes, amphipods, hydroids, bryozoans, flatworms, mussels and sponges. 

These species become prey for finfish, shrimps, and blue crabs. Shell bottoms 

also provide hard, complex substrate to an abundance of plants and animals. 

Thus this habitat supports many resident and transient fish and invertebrates that 

are ecologically and economically important (Street et al., 2005). Shell bottom is 

an important refuge, spawning area, nursery, and foraging area for a diverse 

community. 

http://www.cop.noaa.gov/stressors/climatechange/current/slr/habitats.html

In the wind-driven Pamlico Sound system north of Cape Lookout, oyster reefs 

consist overwhelmingly of subtidal beds. In the Albemarle-Pamlico estuary, 

oysters are concentrated in the lower portion of Pamlico Sound tributaries, along 

the western shore of Pamlico Sound, and to a lesser extent behind the Outer 

Banks (Street et al., 2005).

The status of the oyster fishery in North Carolina is "concern".

http://www.ncdmf.net/stocks/index.html

Oyster harvests in North Carolina have shown a decrease of 90% from historical 

landings (Ortega & Sutherland, 1992). Oysters are harvested from October to 

March with tongs, rakes, or by hand, in intertidal areas and shallow water along 

the coast. They are also caught by dredges in parts of the Pamlico Sound.

NCDMF website http://www.ncfisheries.net/shellfish/shellfish.htm

Based on USACE survey data collected during the late summer of 2009, a low 

relief shell bottom habitat covering 0.20 square-miles is located within the 17.25-

square-mile surveyed area (i.e., 1% coverage) (Table 4.02). 

NCDMF manages ten existing oyster sanctuaries located in estuarine waters 

from Dare to Carteret counties, with one in the planning stages. The project area 

is located in relative proximity to two of the oyster sanctuaries (see Figure 3.01). 

Croatan Sound Sanctuary, established in 1996, covers 7.7 acres and includes 
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1,800 tons of riprap, 4,000 bushels of oyster shells, 2,640 bushels of surf clam 

shells, and 4,000 bushels of limestone marl. This site is located about 2.3 miles 

north of the project area near Roanoke Island. Crab Hole Oyster Sanctuary, 

established in 2003, covers 30.5 acres. This sanctuary is located about 0.6 miles 

south-west of the potential project area and is comprised of 16,170 tons of riprap.

The attributes of all 10 sanctuaries are shown Appendix I.

Future-without project conditions. Shell bottom has been identified as a 

habitat of “concern” due to long-term decline primarily due to overharvesting and 

habitat disturbances (NCDMF website). Other factors contributing to oyster 

decline include pollution, particularly at river mouths and tidal creeks, and natural 

disease by parasites such as DERMO. Shell bottom declined throughout the 20th

century with landings today at 10% of the historic quantities. However, sampling 

data shows DERMO (the oyster parasite responsible for disease in the past) has 

declined in recent years and commercial landings have shown some 

improvement (Street et al., 2005; NCDMF, 2008); however, habitat (shell bottom) 

availability is expected to remain a problem, as little generation of shell bottom 

has occurred within this period of oyster decline. Future conditions are 

unpredictable, as disease and human impacts may change radically over the 

next 50 years. However, it is expected that the habitat will remain stable or begin 

to gradually improve with continued interagency coordination and continued 

Federal/non-Federal partnerships directed at restoration of shell bottom.

4.2.1.3 Soft Bottom

Soft bottom communities constitute the majority of aquatic habitat in Pamlico 

Sound. Highly transient communities of macro-invertebrates utilize the area as 

primary habitat. Seasonal disruptions of the soft bottom from major storms and 

hurricanes make the area a diverse high energy zone that constantly exhibits 

changes in its topography. 

These habitats are dynamic elements of the coastal landscape that change with 

shifting patterns of sediment deposition and erosion. Despite a lack of structure, 

these surface sediments support an abundance of microscopic plants and 

burrowing animals. North Carolina classifies soft bottom habitats as: unvegetated shoreline, beaches, intertidal flats and sub tidal bottom in rivers creeks 

and sounds. The physical and chemical properties of soft bottom habitat affect 

the benthic organism that dwell there. The shoreline and soft bottom in the 

northern geologic province consist of four different types of sediment: sand, peat 

inorganic mud, and organic rich mud (ORM). ORM comprises about 70% of NC 

estuarine substrate and is concentrated in the central basins of sounds (Street et 

al., 2005). The southern estuarine system has soft bottom composed of sloped 

mudflats with extensive tidal channels supporting extensive saltwater marshes

due to larger tide range. These large ranges are also found near the 20 inlets 

through the barrier islands. 
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One of the most important functions of soft bottom habitat is its enabling of 

foraging to several trophic levels due to high concentrations of organic matter 

transported to and produced on soft bottom. This habitat is utilized in this 

capacity by an abundance of diverse invertebrates, including herbivores, 

detritivores, and various fish as you move up the food chain. (Street et al., 2005). 

http://www.cop.noaa.gov/stressors/climatechange/current/slr/habitats.htm

USACE surveys identified 14.79 square-miles of soft bottom in the 17.25-squaremile survey area (i.e. 86% coverage).

Future-without project conditions. Inadequate data exists regarding the future 

conditions of the soft bottom habitat. As a dynamic habitat type that is highly 

resistant to any change in conditions it is anticipated that soft bottom will remain 

status quo with only minor changes occurring regarding the quantity of soft 

bottom relative to wetlands, SAV, and shell bottom that are much less stable 

habitats (Street, et al., 2005).

4.2.2 Bird Islands

There are seven man-made sandy islands in the project vicinity that provide a 

large portion of the primary nesting habitat for colonial shorebird species. 

Species include brown pelicans, royal and sandwich terns, various species of 

gulls, and the American Oyster Catcher. These islands were originally built for 

and are commonly used as disposal through control of effluent islands that 

receive sandy material from the nearby navigation channel. These islands 

require an inflow of sediment to remain stable, but are limited in size to prevent

predatory hazards that would be associated with a larger island. Two such 

Islands, Wells and Parnell, are located within the 17 square-mile project study 

area. They have exceeded their sand disposal capacity and are no longer 

available for disposal until they have receded back to a manageable size as 

appropriate for nesting bird islands. 

Future-without project conditions. Future conditions of the bird islands should 

remain similar to current conditions with cycles of sand placement on the island 

followed by the natural erosion of material. Without additional locations for 

placement of sand materials, navigational maintenance of the nearby channels 

would require the use of the islands increasingly beyond their approved size 

which could result in issues such as higher predation of the nesting birds and 

establishment of plant species that may restrict nesting (USACE-ERDC, 2008). 

These islands’ suitability for nesting is monitored by the North Carolina Wildlife 

Resources Commission. While there are no current plans for additional bird 

islands, a dredged material management plan (DMMP) for the Manteo 

(Shallowbag) Bay Navigation Project is underway and includes considerations for 

construction of additional bird islands along the interior channels of the 

navigation project, including Old House Channel. 
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4.2.3 Wetlands 

The estuarine waters and wetlands of Pamlico-Albemarle Sound provide critical 

nursery areas for more than 75 species of fish and shellfish. Juvenile sea trout, 

flounder, blue crab, and shrimp, the most commonly fished species, all depend 

on estuarine wetlands for protection and food. Shrimp production, in particular, 

has been shown to be directly proportional to the acreage of vegetated wetlands 

in an estuary. The Clean Water Act and the state's Coastal Area Management 

Act have decreased the state's wetland loss rate, but coastal states such as 

North Carolina are still losing wetlands to development more rapidly than is 

occurring in inland states, particularly in the southeast United States. 

http://www.nmfs.noaa.gov/habitat/habitatconservation/publications/

habitatconections/num2.htm

Wetlands are areas that are inundated or saturated by surface water or 

groundwater at a frequency and duration sufficient to support, and that under 

normal circumstances do support, a prevalence of vegetation typically adapted 

for life in saturated soil conditions, as defined by the Code of Federal Regulations

(33 CFR 328.3). Wetlands have three essential characteristics: hydrophytic 

vegetation, hydric soils, and wetland hydrology.

Coastal wetlands that may occur in the project vicinity include salt marshes, 

bottomland hardwood swamps, fresh marshes, submerged aquatic vegetation 

(SAV) and pocosins.

With the exception of SAV as shown on figure 4.04, no vegetated wetlands are 

located within the 17 square-mile project vicinity. The closest nearby wetlands 

are tidal marshes found about 4 to 6 miles away. 

Future-without project conditions. According to Dahl (1990), by the mid1980s, North Carolina had lost up to 50 percent of its estimated original wetlands 

acreage. From 1998 to 2004, in the United States, wetland gains are estimated 

at 32,000 acres annually (Stedman and Dahl 2008). However, during that same 

period, coastal watersheds of the United States adjacent to the Atlantic Ocean 

experienced a net loss of 15,000 acres of estuarine intertidal and freshwater 

wetlands (Stedman and Dahl 2008). Estuarine emergent wetlands showed the 

greatest loss declining by about 1 percent on the Atlantic Ocean coast during the 

6-year period of analysis. According to Stedman and Dahl (2008), more than half 

of the U.S. population lives in coastal areas, and development was a major factor 

in the loss of coastal wetlands along the Atlantic and Gulf of Mexico. Rising sea 

level, subsidence, and erosion processes also contribute to coastal wetland loss 

(Stedman and Dahl 2008).

.
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4.3 Threatened and Endangered Species

An updated list of Endangered and Threatened Species of plants and animals 

that are expected to occur in the vicinity of Pamlico Sound for the project area 

are listed inTable 4.03 which was obtained from National Marine Fisheries 

Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS). The actual 

occurrence of a species depends upon the availability of suitable habitat, the 

season of year relative to a species temperature tolerance, migratory habits, and 

other factors.
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Table 4.03. Endangered and Threatened Species Potentially Occurring in Project Vicinity

Species Scientific name Federal 

Status

Birds:

Piping plover Charadrius melodus T

Roseate tern Sterna dougallii dougallii T

Marine Mammals:

Blue whale Balaenoptera musculus E 

Finback whale Balaenoptera physalus E

Humpback whale Megaptera novaeangliae E

North Atlantic right whale Eubalaena glacialis E

Sei whale Balaenoptera borealis E

Sperm whale Physeter macrocephalus E

West Indian Manatee Trichechus manatus E

Reptiles:

Green sea turtle Chelonia mydas T 

Hawksbill sea turtle Eretmochelys imbricata E

Kemp's ridley sea turtle Lepidochelys kempii E

Leatherback sea turtle Dermochelys coriacea E

Loggerhead sea turtle Caretta caretta T 

American alligator Alligator mississippiensis T (S/A)

Fishes:

Shortnose sturgeon Acipenser brevirostrum E

Atlantic sturgeon Acipenser oxyrinchus E

T(S/A) = threatened due to similarity of appearance. A taxon that is threatened due to 

similarity of appearance with another listed species and is listed for its protection. Taxa 
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listed as T(S/A) are not biologically endangered or threatened and are not subject to 

Section 7 consultation. 

The species expected to occur in the project area are the West Indian manatee 

(Trichechus manatus), shortnose sturgeon (Acipenser brevirostrum), Atlantic 

Sturgeon (Acipenser oxyrinchus), the multiple species of sea turtle that frequent 

the North Carolina coast as well as, the shore bird species of piping plover 

(Charadrius melodus) and roseate tern (Sterna dougallii dougallii that may use 

the bird islands.

Whale species are not expected to occur within Pamlico Sound as whale species 

tend to stay off the coast of North Carolina and do not enter the sound. The 

project vicinity does not include habitat of the dune plant seabeach amaranth 

(Amaranthus pumilus) and, therefore, this species would not be encountered.

Manatee. There is no information available that would allow the prediction of 

West Indian Manatee’s occurrence at any given site at any given time. It can only 

be assumed based on recorded sightings that the likelihood of it occurring in the 

area is low. 

Future - without project conditions. Based on an unpublished species profile 

for the West Indian manatee (specifically the Florida manatee) by the U.S. Fish 

and Wildlife Service, a general trend appeared from 1993 to 2001 showing a 

population increase of manatees in Florida. As North Carolina does not have a 

resident population of manatees it is assumed that manatees spotted in North 

Carolina are transients from the south, most probably Florida. For this reason 

data gathered in Florida can be utilized to ascertain the future likelihood on 

manatee sightings. With increasing water temperatures and the gradual increase 

in population size, it can be expected the likelihood of an encountering a 

manatee will increase over time within the project area but should not increase to 

the degree that a resident community of manatees would inhabit Pamlico Sound.

http://ecos.fws.gov/docs/recovery_plan/011030.pdf

Shortnose Sturgeon. The shortnose sturgeon range extends along the Atlantic 

seaboard from the Saint John River in New Brunswick, Canada to the Saint 

Johns River, Florida. Historical records indicate that shortnose sturgeon used to 

be abundant within Pamlico Sound but up until less than a decade ago, were 

thought to be extirpated from North Carolina. In 1998, NCDMF captured an adult 

shortnose sturgeon in Western Albemarle Sound providing evidence for the 

existence of a shortnose sturgeon population (NMFS, 1998). There is no 

breeding habitat available for the species in the project vicinity; however, adults 

may be encountered in the project area when the over-wintering population 

moves into the Roanoke/Chowan River Basin. 

Atlantic sturgeon. Ranges of the Atlantic sturgeon are similar to that of the 

shortnose sturgeon discussed above with the species’ historic range including
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major estuarine and riverine systems that spanned from Hamilton Inlet on the 

coast of Labrador to the Saint Johns River in Florida (Murawski and Pacheco, 

1977; Smith and Clungston, 1997). Atlantic sturgeon were once abundant in 

many coastal rivers and estuaries in North Carolina. The largest historic Atlantic 

sturgeon fisheries occurred in the Cape Fear River and the Roanoke 

River/Albemarle Sound system where current spawning has been documented in 

both systems (ASSRT, 2007). Man-made structures, such as dams, have 

limited the species spawning habitat and ability to reproduce. The Atlantic 

sturgeon is listed as Endangered. Within the Federal Register dated February 6, 

2012 (Volume 77, Number 24), NMFS issued a final determination to list the 

Carolina and South Atlantic distinct population segments (DPSs) of Atlantic 

sturgeon (Acipenser oxyrinchus oxyrinchus) as endangered under the 

Endangered Species Act (ESA) of 1973, as amended. This final rule was made 

effective April 6, 2012. There are currently recovery programs in place for 

Atlantic sturgeon. As with the shortnose sturgeon, there is no breeding habitat 

available for the species in the project vicinity but adults may be encountered in 

the project area. Although it is unlikely species may occur in the project area, it is 

expected that the sturgeon are mobile enough that they will not be restricted from 

moving outside of the project vicinity.

Future - Without Project Conditions. Man-made structures that restrict the 

spawning of shortnose and Atlantic sturgeon will continue to keep populations at 

a low level. Data is unclear regarding the locations and distributions of either

populations within Pamlico Sound so population trends and other tools used to 

determine the health and status of a population are unavailable at this time. It is 

anticipated that continued recovery programs and the active removal of many unnatural structures that currently block spawning grounds for the shortnose and 

Atlantic sturgeon will continue to bolster the native populations and may promote 

the growth of the native populations, increasing the chances of an encounter.

http://www.nmfs.noaa.gov/pr/pdfs/recovery/sturgeon_shortnose.pdf

Sea Turtles. Sea turtle species commonly associated with the North Carolina 

coast have been known to traverse through Oregon Inlet and into Pamlico 

Sound. The loggerhead and green sea turtle are considered to be the only 

species to nest on the beaches nearest the project area. However, the 

leatherback, hawksbill, and Kemp’s ridley sea turtle have been documented 

within or on the adjacent beaches of Pamlico Sound. While these species may 

occur within the project area, it is unlikely that sea turtles will be encountered due 

to the time of year that construction phase work would be proposed and the 

mobility of sea turtles to move outside of project range.

Future – Without Project Conditions. Population trends from NOAA and 

analyses of historic and recent abundance indicate that extensive population 

declines have occurred over the past 100 years with an overall decline in mature 

females nesting. In particular from 1998, after seeing an upward trend in nests 

since 1989, populations of nesting turtles dropped 43%. Mitigation of hazards 
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that are suspected of contributing to the decline of turtles including predation by 

foxes, coastal trawling impacts, and more strict dredging requirements should 

contribute to continuity of the various species. However, limited data makes a 

determination on the future of the species difficult. It is expected that populations 

may slow in their decline and, in some cases begin to recover, but will not 

recover to the point of de-listing during the 50 year period of interest. 

http://www.nmfs.noaa.gov/pr/species/turtles/

Birds. Piping plover (Charadrius melodus) and roseate tern (Sterna dougallii 

dougallii) are fairly common along the North Carolina Coast. Both species are 

considered shorebirds that nest in low numbers along the area beaches and bird 

islands. Potential nesting habitat is located outside of the 17 square-mile survey 

area and species will not be in direct contact with the proposed project.

Future – Without Project Conditions. Populations are expected to stay status 

quo during the 50 year study period with little change from their current 

“Threatened or Endangered Status”. Mortality of adults during migration and 

major storm events along with occasional predation will continue to occur. 

Occasional shifting of nesting locations may occur but populations should remain 

in the general vicinity.

4.4 Benthic Resources

Benthic resources in the Northern Pamlico Sound are variable, from limited 

resources occurring in frequently dredged channel bottoms to complex and 

diverse assemblages occurring in stable grass bed areas. Ecologically and 

economically important benthic species known from the project area include blue 

crabs (Callinectes sapidus), shrimps (Penaeus spp.), clams (Mercenaria 

mercenaria), and oysters (Crassostrea virginica). 

The Southeast Coast Benthic Index rated the benthic condition of the AlbemarlePamlico Estuarine Complex as fair with 65 percent of the area rated in good 

condition, and sixteen (16%) percent of the area rated poor. None of the poor 

location are in the project area; the majority are in the Neuse Estuary. Degraded 

areas were often associated with adverse water and sediment quality (NEPCC, 

2007).

Future - Without Project Conditions. Future conditions in the project vicinity 

are expected to remain stable with an overall quality rating of fair. There is no 

data indicating a change in this condition.
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4.5 Essential Fish Habitat (EFH) and Fisheries

The 1996 Congressional amendments to the Magnuson-Stevens Fishery 

Conservation and Management Act (MSFCMA) (PL 94-265) set forth new 

requirements for the National Marine Fisheries Service (NMFS), regional fishery 

management councils (FMC), and other federal agencies to identify and protect 

important marine and anadromous fish habitat. These amendments established 

procedures for the identification of Essential Fish Habitat (EFH) and a 

requirement for interagency coordination to further the conservation of federally 

managed fisheries. The project area may include species that are managed by, 

or are of particular interest to the Mid and South Atlantic Fishery Management 

Councils, as well as the Atlantic States Marine Fisheries Commission. The NMFS 

Southeast Region is the point of contact (POC) for EFH for this project. Table 

4.04 lists, by life stages, the 14 fish species which may occur in Pamlico Sound 

and which are managed under MSFCMA. These fish species and habitats 

require special consideration to promote their viability and sustainability. The 

potential impacts of the proposed project on these fish and habitats are 

discussed in Section 7.5.
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Essential Fish Habitat Species, Pamlico Sound

Dare County, NC

EFH Fish 

Species

Life Stage 

Present

EFH Fish 

Species

Life Stage 

Present

Bluefish E L J A Black Sea Bass L J A 

Summer 

Flounder L J A Spiny Dogfish E L J A

Gag Grouper J Brown Shrimp E L J A

Gray Snapper J Pink Shrimp E L J A

Cobia E L J A White Shrimp E L J A

King Mackerel J A Sandbar Shark J A

Spanish 

Mackerel J A Sheepshead J A

Life Stages E=Eggs; L=Larval; J=Juvenile; A=Adult

Table 4.04. Essential Fish Habitat (EFH) Species Present in Pamlico Sound, Dare 

County, North Carolina. Source: NMFS, Beaufort, North Carolina, October 1999.

The Fishery Management Plan Amendments of the South Atlantic Fishery 

Management Council identify a number of categories of Essential Fish Habitat 

and Habitat Areas of Particular Concern, which are listed in Table 4.05. While all 

26 of these habitat categories occur in waters of the southeastern United States, 

many are absent from the Pamlico Sound Estuary. Those absent include 

estuarine scrub/shrub mangroves which require a more tropical environment and 

several areas that are geographically removed from the project area including: 

Hoyt Hills located in the Blake Plateau area in water 450-600 meters deep, Cape 

Fear Sandy Shoals also known as Frying Pan Shoals, Big Rock and Ten-Fathom 

Ledge located off Cape Lookout, Hatteras Sandy Shoals, New River, and Bogue 

Sound. In addition, the Pamlico Sound does not include marine (ocean) areas 

or state-designated areas of importance for managed species (primary nursery 

areas). 

Areas found in the Pamlico Sound include: estuarine water column, aquatic beds, 

estuarine emergent wetlands, oyster reefs and shellbanks, palustrine forested 

wetlands, seagrass (submerged aquatic vegetation).
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The 17 square-mile project study area includes estuarine water column, aquatic 

beds, oyster reefs and shellbanks, and seagrass (submerged aquatic 

vegetation). 

Table 4.05. Categories of Essential Fish Habitat and Habitat Areas of Particular Concern in 

Southeast States1

.

ESSENTIAL FISH HABITAT GEOGRAPHICALLY DEFINED HABITAT 

AREAS OF PARTICULAR CONCERN

Estuarine Areas Area – Wide

Aquatic Beds Council-designated Artificial Reef Special 

Management Zones

Estuarine Emergent Wetlands Hermatypic (reef-forming) Coral Habitat & 

Reefs

Estuarine Scrub / Shrub 

Mangroves

Hard Bottoms

Estuarine Water Column Hoyt Hills

Intertidal Flats Sargassum Habitat

Oyster Reefs & Shell Banks State-designated Areas of Importance of 

Managed Species

Palustrine Emergent & Forested 

Wetlands

Submerged Aquatic Vegetation (SAV)

Seagrass

North Carolina

Marine Areas

Big Rock

Artificial / Manmade Reefs Bogue Sound

Coral & Coral Reefs Capes Fear, Lookout, & Hatteras (sandy shoals)

Live / Hard Bottoms New River

Sargassum The Ten Fathom Ledge

Marine Water Column The Point

1

Areas shown are identified in Fishery Management Plan Amendments of the South 

Atlantic Fishery Management Council and are included in Essential Fish Habitat: New 

Marine Fish Habitat Mandate for Federal Agencies. February 1999. (Tables 6 and 7).

Overall, based on the fish tissue contaminants index, the Albemarle-Pamlico 

Estuarine Complex is rated good to fair. Ten percent of the stations sampled 

exceeded the risk-based EPA Advisory guidance values and were rated poor. 
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Twenty percent of stations were rated fair and seventy percent were rated good 

with the only contaminants measured being total PAHs and total PCBs.

Future - Without Project Conditions. Declining stocks of local populations of 

fish that include; Atlantic croaker, Atlantic sturgeon, eastern oyster, red drum, 

striped bass, summer flounder, weakfish, and herring are apparent in downward 

trends of commercial landings despite improvements in fishing methodologies 

and gear. It is expected that without better management practices that manage 

overfishing and habitat loss this trend may continue (NEPCC, 2007). 

4.6 Sediments

The assessment of the existing condition of sediment in the Project Study Area is 

based largely on vibracore sampling by the USACE during the feasibility study. 

These boring samples were then analyzed by Terracon Inc. The results of the 

laboratory testing of these samples are presented on the grain size analysis 

sheets, summarized in the boring logs, and provided in Table E-2 in Appendix E. 

In general, the materials encountered in the northern portion of Old House 

Channel, Range 2 consist of fine sand (SP) and fine sand with silt (SP-SM) with 

composite percent silt content at less than 10%. The materials encountered in 

the southern portion of Old House Channel, Range 2 generally consists of fine 

sand (SP), fine sand with silt (SP-SM), silty fine sand (SM), and elastic silt with 

sand (MH). The material encountered in the potential placement areas ranges 

from fine sand (SP) in some areas, to fine sand with silt (SP-SM), silty fine sand 

(SM), and elastic silt with sand (MH). 

Future - Without Project Conditions. The distribution of bottom sediments is 

not expected to have any significant change over time. Suspended solids have 

trended downward over the last 30 years with spikes occurring during major 

storm events. Conditions at the project area are not expected to vary greatly 

outside of those storm events. The sediment quality index that evaluates toxicity, 

contaminants, and carbon determined that the Albemarle-Pamlico Estuarine 

complex is rated good to fair with two sampling sites near the project rated good. 

The overall condition rating was distributed as 93% good and seven percent 

rated poor. These evaluations are not anticipated to drastically change in the 

foreseeable future (NEPCC, 2007).
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4.7 Coastal Processes

The Project Study Area is located near Oregon Inlet in a highly dynamic area 

subject to external forces including wind, waves, and tides. The predominant 

winds occur from the northeast and the southwest which is typical of the entire 

coast of North Carolina. Winds play an important role in the tides. Fluctuation of 

the water level as a result of wind action is a common and daily occurrence. 

Water levels are determined primarily by the speed, direction, and duration of 

surface winds. Astronomical tides play a small role in the water level due to the 

distance from Oregon Inlet and the buffering provided by the barrier islands. 

Waves in the Project Study Area are affected more by winds than by the ocean 

swell entering the sound through Oregon Inlet. The area is dynamic with impacts 

from frequent storms. Seven named tropical storms have made direct landfall on 

the area in the last ten years, in addition to nor’easters (www.ncclimate.ncsu.edu). 

Future - Without Project Conditions. Existing coastal processes within the 

project area are not expected to change. The external forces of wind, waves and 

tides will continue to impact the project area. Water levels will continue to be 

impacted primarily by wind with minor impacts resulting from astronomical tides 

(for Sea Level Rise see analysis in Section 4.1.3)

4.8 Air Quality

The Washington Regional Office of the North Carolina Department of 

Environmental and Natural Resources has air quality jurisdiction for the project 

area. The ambient air quality for Dare County has been determined to be in 

compliance with the National Ambient Air Quality Standards, and this county is 

designated as an attainment area. The State of North Carolina does have a State 

Implementation Plan (“SIP”) approved or promulgated under Section 110 of the 

CAA. However, for the following reasons, a conformity determination is not 

required:

a. 40 CFR 93.153 (b), “For federal actions not covered by paragraph (a) of this 

section, a conformity determination is required for each pollutant where the total 

of direct and indirect emissions in a nonattainment or maintenance area caused 

by a federal action would equal or exceed any of the rates in paragraphs (b) (1) 

or (2) of this section.” Dare County has been designated by the State of North 

Carolina as an attainment area.

b. The direct and indirect emissions from the project would fall below the 

prescribed minimum levels (58 Fed Reg. 93.153(c )(1)) and, therefore, no 

conformity determination would be required.

c. The ambient air quality for Dare County has been determined to be in 

compliance with the National Ambient Air Quality Standards. This project is not 

anticipated to create any adverse effect on the air quality of this attainment area.
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Future - Without Project Conditions. Air quality is not expected to decline in 

the future. Recent results of air quality testing (ozone and particle pollution) by 

the NC Division of Air Quality have indicated a decrease in high exceedance 

days in North Carolina showing that air quality may be improving over time 

http://daq.state.nc.us/news/pr/2010/ozone_forecasts_03312010.shtml

Dredging operations that release minimal levels of emissions in the project area 

will continue on a regular dredge cycle to maintain navigation routes.

4.9 Socio-Economics and Recreation

Recreational and commercial fisherman use the Pamlico Sound extensively for 

fisheries and shellfish resources, making up a large percentage of North 

Carolinas’ total revenue for fisheries. The Sound is especially known for its blue 

crab and oyster resources. Commercial fishing practices in the basin include 

pound nets, long haul seines, shrimp and crab trawls, crab pots, and sink gill 

nets. Shellfish (including crabs, oysters, and bay scallops) are taken by tonging, 

raking, bull raking, hand harvesting, and dredging.

Tourism in the counties surrounding Pamlico Sound relies on maintaining a high 

level of support from fishing tournaments and the influx of boaters that utilize the 

many marinas within Pamlico Sound. The Project Study Area is popular for 

fishing due to its vicinity to Oregon Inlet and its containment of a variety of 

habitats. Sidescan data has indicated SAV, oyster reefs, shoals, and deep water 

habitats, which attract fish and fisherman to the area (Figure 4.04). 

Navigational support to marinas and vessels providing goods and supplies, as 

well as bolstering the local, recreational, and tourism markets in the surrounding 

area reinforces the need for navigation channels and the constant maintenance 

that is required to keep the channels open. Providing alternative methods for 

placement of material that has been removed from these navigational channels is 

crucial to maintaining the economic stability of the surrounding area that relies 

heavily on access to the waterways. 

Future - Without Project Conditions. Activities that contribute to the socioeconomics of the greater community in the surrounding project area are closely 

tied to commercial fishing and recreational vessel access and passage. Safe 

and viable vessel passage is expected to remain a critical component of the 

area’s socio-economic structure. This requires that navigation channels remain 

open; therefore, channel maintenance requirements are not expected to change

significantly in the future.
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4.10 Cultural Resources

The study area is located in Pamlico Sound within the Outer Banks of North 

Carolina, and specifically, the Oregon Inlet vicinity. The inlet was created by a 

storm in September 1846 that pushed water over Bodie Island (Angley, 1985). 

Oregon Inlet remained unimproved, save lighthouse constructions and Civil War 

fortifications, and migrated approximately a mile south, before channel dredging 

was begun in 1910 to link Manteo (Shallowbag) Bay to the inlet (Angley, 1985).

Historical research has identified the loss of ninety vessels in the vicinity of 

Oregon Inlet (Tidewater Atlantic Research, 1992). Despite the large number of 

sunken vessels in the vicinity, there are no known recorded archaeological sites 

within the proposed project area (North Carolina State Historic Preservation 

Office. Letter to Corps of Engineers 18 June 2009). The Corps of Engineers will 

consult with North Carolina Office of Archaeology’s Underwater Archaeology 

Branch when specific construction areas are identified.

Future - Without Project Conditions. No known recorded archaeological sites 

are within the proposed project area (North Carolina State Historic Preservation 

Office. Letter to Corps of Engineers 18 June 2009). Therefore, there would be no 

effect or change from existing conditions that would affect cultural resources. 

However, there is always the possibility that an unknown cultural resource will be 

identified in the future. 

4.11 Hazardous, Toxic, and Radioactive Wastes

The project area under consideration is not located in or near an industrial site or 

dump. If hazardous and toxic wastes are identified in the area, response plans 

and remedial actions will be conducted as appropriate. 

Future - Without Project Conditions. Waste sites are not expected to be 

discovered in the future.

4.12 Floodplains

The Pamlico Sound proposed project area is not located within a floodplain. It is

submerged. 

Future - Without Project Conditions. Future conditions analysis suggests that 

the project area will not become a floodplain.
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4.13 Other Environmental Considerations

The following environmental factors have been considered based on existing and 

future conditions and due to the unlikely circumstance that they will change or be 

impacted were excluded from further analysis: aesthetics, noise, and geology.

5.0 PLAN FORMULATION AND ALTERNATIVE EVALUATION

This section discusses problems, opportunities, restoration objectives and 

constraints within the study. Based on these problems, opportunities, objectives 

and constraints, a series of restoration alternatives have been developed..

5.1 Public Concern

Input was received through coordination with the sponsor, coordination with other 

agencies, and public distribution of the project scoping letter. A discussion on 

public involvement is included in Section 9.0 of this report. The public concerns 

that are related to the establishment of planning objectives and planning 

constraints are:

1. The State of North Carolina has indicated concern for the historical loss of 

oyster reef habitat in Pamlico Sound.

2. Both state and Federal resource agencies have expressed a desire to 

restore a self-sustaining network of oyster reef habitat in Pamlico Sound. 

The Sponsor, the State of North Carolina, has indicated a desire for 

beneficial use of the sediments at Old House Channel for oyster reef 

restoration.

3. The North Carolina Wildlife Resources Commission (WRC) has expressed 

the preference for a maximum island size limit for Wells and Parnell 

disposal islands, which are located along Old House Channel. These 

disposal islands also serve as bird sanctuaries. Due to frequent dredging 

needs in the vicinity of these islands, both sites currently are at or exceed 

established limits. The WRC has asked that both sites be used on a less 

frequent 2-3 year disposal cycle to allow time for natural erosion to reduce 

the size of the islands, minimizing the potential for establishment of avian 

predators (US ERDC, 2008).

.
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5.2 Assessment of Problems, Opportunities, Objectives and 

Constraints

5.2.1 Problems and Opportunities

This section describes the public concerns in the context of problems and 

opportunities that can be addressed through water and related land resource 

management. Solving these problems and opportunities provides basis for 

motivating & allocating the partners’ pooled resources (Planning Manual, pg. 78).

The problem identified in this CAP Section 204 study is a historic loss of oyster 

reef habitat in Pamlico Sound, NC. 

1) Due to the importance of oysters as a keystone species in estuarine 

ecosystem health (Street et al., 2005; Peterson et al., 2003; NCDMF, 2009) and 

their sharp decline in population in North Carolina from historic levels (Ortega & 

Sutherland, 1992), the State of North Carolina has made oyster restoration a 

high priority as expressed in the Blue Ribbon Report (Frankenberg, 1995). Due 

to historic overharvesting, destruction of habitat, pollution and disease, oyster 

landings are estimated to be only ten percent of what they were just over a 

century ago (Ortega & Sutherland, 1992). According to NCDMF 2001a, the 

primary cause of initial oyster reef decline and degradation in Pamlico Sound 

was the introduction and use over time of the “oyster dredge” as a harvesting 

practice. First introduced in 1889, the practice of oyster dredging involves a boat 

pulling a large rake along the sea floor (particularly over oyster reefs), bringing up 

the oysters in it’s path. Oyster dredging is still in practice today, but with 

restrictions. A decline in oyster habitat from historical levels in the Pamlico Sound 

is viewed as a concern by both public and private entities. 

2) There are opportunities in the study area to restore oyster reef habitat. This 

would contribute to local, state, and national goals of restoring the oyster 

population in North Carolina waters. Successful establishment of oyster reefs in 

the project vicinity has been demonstrated by the State of North Carolina (see 

Section 3.2). 

3) There is an opportunity to alleviate strain on Wells, Parnell and MN Disposal 

Islands along Old House Channel (Range 2) by providing an alternative disposal 

location. These disposal islands are also managed as bird nesting islands, 

through control of effluent discharge practices. 

5.2.2 Planning Objectives

These planning objectives reflect the problems and opportunities and represent 

desired positive changes in the without project conditions. The planning 

objectives are:
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1. Contribute to State network of self-sustaining oyster reefs in AlbemarlePamlico National Estuary as described by the NCORSC’s Oyster 

Restoration and Protection Plan. 

2. Increase acreage of oyster reefs in Pamlico Sound, NC by 5 to 20 acres. 

This range is considered appropriate based on anticipated dredged 

material volumes.

3. Divert dredged material from Wells, Parnell and/or MN disposal islands. 

5.2.3 Planning Constraints

Study-specific constraints that will guide formulation and screening of alternatives

include:

a. Avoid disturbing existing high value areas (site construction & pipe 

placement)

Site construction and related activities must avoid existing SAV, 

shell bottoms, and cultural resources. This risk is being minimized 

through a detailed survey of the project study area.

b. Avoid conflicting with other area fisheries such as crab trawling

This risk is being minimized through coordination with local field 

experts & NCDMF as a liaison to the fishing community.

c. Avoid sand quality that is inappropriate for beneficial use, and sediment 

material inappropriate for foundational support.

The risk is being minimized through geotechnical vibracore 

sampling.

d. Avoid alternatives requiring mitigation.

e. Prohibited from removing material directly from Wells and Parnell Disposal 

Islands for construction material (source: SAD CAP Processes and 

Procedures, pg.11).

f. Sufficient water depth required to contain submerged oyster reef with a

7feet navigation clearance (Based on State of North Carolina policy).

5.3 Potential Restoration Alternatives

This section describes the Alternative development for a beneficial use of 

dredged material project at Old House Channel. A number of general measures 

were identified that would meet one or more of the planning objectives. These 
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measures underwent a preliminary screening process. The retained measures 

were evaluated and then further developed into alternatives.

5.3.1 Description of Measures

A management measure is a feature or activity at a site, which addresses one or 

more of the planning objectives. A variety of measures were considered, some 

of which were found to be infeasible due to technical, economic, or 

environmental constraints. Each measure was assessed and a determination 

made regarding whether it should be retained in the formulation of alternative 

plans. The descriptions and results of the evaluations of the measures 

considered in this study are presented below, and described afterwards:

1. NO ACTION

2. Beach Placement on Cape Hatteras National Seashore or Pea Island 

National Wildlife Refuge

3. Additional Bird Island Creation

4. Marsh Protection

5. Oyster Reef Construction

1. No Action. The USACE is required to consider the option of “No Action” 

as one of the alternatives in order to comply with the requirements of the 

National Environmental Policy Act (NEPA). No Action assumes that no 

project would be implemented by the Federal Government to achieve 

planning objectives. No Action, which is also referred to as the “Without 

Project Conditions”, forms the basis from which all other alternative plans 

are measured. Under the No-Action plan, the USACE would do no 

restoration efforts at Old House Channel, and the base plan for managing 

dredged material would remain in place. State efforts to meet Local, 

State, & National goals for oyster restoration in Pamlico Sound would be 

expected to continue, but without restoration in the identified area of need 

of Old House Channel. Strain on Wells & Parnell disposal islands, as well 

as disposal island MN would continue without any alleviation from an 

alternative disposal option.

2. Beach Placement on Cape Hatteras National Seashore or Pea Island 

National Wildlife Refuge. This measure would require pumping dredged 

material from Old House Channel to the closest beach (roughly 5 miles 

away) for shoreline placement. This would divert material from Wells and 

Parnell disposal islands. The National Parks Service (NPS) is responsible 

for Cape Hatteras National Seashore, which is north of Oregon Inlet. The 

NPS has stated that it is highly unlikely that they would permit the 

deposition of dredged spoils on the National Seashore property at this 

location. The USFWS is responsible for Pea Island National Wildlife 

Refuge, south of Oregon Inlet. Dredged material from Oregon Inlet is 

already being deposited on Pea Island as part of dredging operations. 
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Further negotiation with the USFWS would be needed to gain permission 

to place material from the interior channels of the Manteo (Shallowbag) 

Bay navigation project, which includes Old House Channel (Range 2). 

3. Additional Bird Island Creation. Dredged material from Old House 

Channel could be used to create another disposal island that could also 

be used as additional bird habitat. Two existing bird islands (Wells & 

Parnell islands) already exist in the project area. A separate Dredged 

Material Management Plan study is currently investigating the creation of 

additional bird islands. However, this conversion of aquatic to terrestrial 

habitat would not address identified oyster restoration needs. 

4. Marsh Protection. Dredged material could be used to protect marsh, 

similar to the USACE project constructed at Festival Park near Manteo. 

However, the nearest shoreline is approximately 5 miles away, and there 

has been no documented need of marsh protection in the vicinity.

5. Oyster Reef Construction. Dredged material from maintenance 

dredging of Old House Channel could be used to build submerged sand 

islands to be topped with cultch for oyster reefs, with various reef 

configurations being considered. Configurations could include placing 

sand in submerged enclosures where good oyster growing conditions are 

found near the navigation channel and where submerged aquatic 

vegetation (SAV) or other significant resources do not exist.

5.3.2 Preliminary Screening of Restoration Measures

Two rounds of preliminary screenings were used before a final array of 

alternatives was moved forward to detailed analysis and evaluation. Costs and 

benefits are not computed at this preliminary screening stage. Conclusions of 

the screening pertain to this Section 204 Study and related objectives and oyster 

reef restoration, and do not preclude other viable options of dredged material 

disposal which may be identified for the larger Manteo (Shallowbag) Bay 

Dredging Project.

Preliminary Screening–Round 1. All of the measures under consideration 

were initially screened based on a number of factors including contribution to 

planning objectives, technical feasibility, economic feasibility, environmental 

acceptability, and mitigation requirements. Based on these factors, 

determinations were made regarding which measures to proceed forward with to 

the second round of screening. This preliminary screening process is 

summarized in Table 5.01.
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Detailed Project Report and Environmental Assessment

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Preliminary Screening – Round 2. Based on the first round of preliminary 

screening, oyster reef construction was carried forward to a second array of 

measures for evaluation and screening. As shown in Table 5.02, various 

configurations and methodologies of oyster reef construction were considered 

and screened based on the same criteria used in the first round of preliminary 

screening. A traditional rock reef such as the State has used was screened out 

because it does not use dredged material as required by the 204 Authority. 

Uncontained sand mounds were screened out as an option due to concerns of 

dredged material migration after placement from currents in the area, particularly 

during significant storm events such as Nor’easters and tropical activity. There is 

also opposition to unconfined disposal from resource agencies. Sandbag reef 

alternatives were also screened out due to uncertainty regarding the feasibility of

placement and filling of sandbags in deep water. Both stone contained and 

sheetpile & stone contained reefs were carried forward for detailed design and 

evaluation.
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5.3.3 Final Array of Alternatives

With those management measures or plans that survived the above screening process, 

a final array of alternatives was formulated. Based on the initial screenings, the 

measures or plans that will be carried forward include no-action, as well as two sandbased oyster reef construction methodologies: stone containment, and sheetpile and 

stone containment. For each construction methodology, various sizes and 

configurations were developed as alternatives. The largest reef sizes/configurations 

were designed to contain approximately all of the anticipated dredged material from one 

dredging cycle along Old House Channel (Range 2) (i.e. roughly 180,000 cubic yards

(cy)). The estimated dredging cycle volume is based on the average pay quantity 

(209,000 cy) removed from Old House Channel (Range 2) for the most recent 3 

dredging contracts. It was assumed that during dredging of 209,000 cy of material there 

would be 15% losses with only 177,650 cy ending up in the containment area. In 

addition, arrays of smaller reef sizes/configurations were also developed for 

consideration. Each of the final plans will utilize dredged material form Old House 

Channel (Range 2) for oyster reef restoration. Any excess material not utilized in reef 

construction would be pumped to one of the nearby disposal islands.

OLD HOUSE CHANNEL (RANGE 2) DREDGING VOLUMES

Dredging Cycles Prior to 2012

Source: USACE Wilmington District Navigation Branch Dredging Records

Year Months Quantity, cubic yards

2004 April – July 230,671

2006 March – May 176,815

2008 - 2009 October 2008 – January 2009 219,304

Site Selection 

The following steps were undertaken to identify an appropriate placement site for oyster 

reef placement. This is illustrated in Figure 5.01.

Step 1: 

An initial 17-square-mile project study area was chosen based on its vicinity to State 

oyster restoration efforts, and identified dredged material disposal needs from Old 

House Channel (Range 2).
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Step 2:

A bathymetric and multi-beam sidescan sonar survey of the project study area was 

conducted by the USACE-ERDC field research facility at Duck, N.C. to map existing 

resources and topography of the area (USACE-ERDC, 2009).

Step 3:

To identify an appropriate placement site for submerged oyster reef construction, 

several screening criteria were used:

1. Avoid disturbing existing high value areas ( wetlands, SAVs, or existing 

shellbottom)

2. Water depth must be sufficient enough to allow 7 feet navigation clearance 

above reef top (based on State of NC Policy).

3. Avoid conflict with other area fisheries, such as crab trawling

4. Placement site must contain enough sand to support the reef structure

Using the data collected from the ERDC boat survey, screening criteria were applied 

using GIS mapping. The specific criteria used for the initial screening of potential 

placement areas were:

a. Eliminate areas with existing SAV

b. Eliminate areas with existing shellbottom

c. Eliminate areas with depth shallower than 11 feet

Step 4:

A vibracore drilling plan to analyze sediment characteristics was developed for the 

remaining area that passed the initial screening phase. However, the slough in the 

North East quadrant of the project study area was eliminated from consideration due to 

inaccessibility for vibracore drilling due to the surrounding shallows. Figure 5.01 depicts 

one boring in the southeastern portion of the project study area outside of the 

designated geotechnical survey area which was conducted as a subsurface exploratory 

investigation only. The two additional borings in the southern portion of the project study 

area were within a smaller designated geotechnical survey area during initial 

investigations.

Step 5:

Based on the results from the vibracore analysis (Section 4.6 and Appendix E), the 

potential placement area was narrowed down further to areas considered to have 

suitable sediment material for placement (sandy bottom areas considered of lower 

biological productivity to provide structural support of construction foundations).

Step 6:

Surface sediment sampling was conducted within the suitable foundation area to verify 

the absence of wintering crab habitat. The final placement site will occur within this 

sampling zone. 
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Figure 5.01 Map of Site Selection Screening Process
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Each of the alternatives will utilize dredged material from Manteo Old House Channel 

Range 2 for creation of a submerged oyster reef habitat. A containment structure will 

be constructed to contain the dredged material. Several containment structure 

alternatives were evaluated. The final arrays of alternatives are listed in Table 5.03 and 

are discussed in the following paragraphs.

Table 5.03

Final Array of Alternatives

Alt Containment Structure # of 

Cells Area (acre) Capacity (cy)

1 None/No Action n/a n/a n/a

2 Sheetpile w/Stone Apron 1 18.6 179,500

3 Sheetpile w/Stone Apron 1 15.06 144,100

4 Sheetpile w/Stone Apron 1 9.7 90,800

5 Sheetpile w/Stone Apron 2 2x9.7 = 19.4 181,600

6 Sheetpile w/Stone Apron 1 5.07 45,500

7 Sheetpile w/Stone Apron 2 2x5.07 = 10.14 91,000

8 Sheetpile w/Stone Apron 3 3x5.07 = 15.21 136,500

9 Sheetpile w/Stone Apron 4 4x5.07 = 20.28 182,000

10 Stone Sill 1 18.6 178,600

11 Stone Sill 1 15.06 143,290

12 Stone Sill 1 9.7 90,100

13 Stone Sill 2 2x9.7 = 19.4 180,200

14 Stone Sill 1 5.07 45,000

15 Stone Sill 2 2x5.07 = 10.14 90,000

16 Stone Sill 3 3x5.07 = 15.21 135,000

17 Stone Sill 4 4x5.07 = 20.28 180,000

Alternative 1 – No Action. 

The USACE is required to consider the option of “No Action” as an alternative in order 

to comply with the requirements of the National Environmental Policy Act (NEPA). No 

Action assumes that no project would be implemented by the Federal Government or by 

local interests to achieve the planning objectives. No Action, which is synonymous with 

the Without Project Conditions, forms the basis from which all other alternative plans 

are measured. Under the no-action plan, the USACE and the Sponsor would not make 

use of dredged material from Old House Channel (Range 2) for oyster reef restoration. 

Instead, all material from future dredging events would continue to be placed on 

disposal islands within the vicinity, with the location likely being either islands Wells, 

Parnell, or MN. No oyster habitat would be created. Although the North Carolina Oyster 

Restoration Steering Committee has recognized the project study area as an area of 

need for oyster restoration, there are currently no other plans for reef restoration in 

addition to the Manteo, Old House Channel, NC Section 204 study.
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Alternative 2 – one 18.6 acre site with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using composite sheetpile to 

create one 18.6 acre containment area for dredged material. An 18.6 acre containment 

area would be able to contain approximately 179,500 cubic yards of dredged material. 

The sheetpile would be driven into the bottom with a resulting top of sheetpile elevation 

4 feet above the sea floor. The outside perimeter of the sheetpile wall would be 

protected with NCDOT Class 2 armor stone (9”-23”). Bedding stone for the armor stone 

would be NCDOT Class B stone (5”-12”). Dredged material from maintenance dredging 

of the federal navigation channel would be pumped into the containment area. The 

dredged material would be covered with NCDOT Class A stone (2”-6”) and oyster shell 

to provide habitat for establishment of oysters. A typical cross section is shown in 

Figure 5.02.

Alternative 3 – one 15.06 acre site with sheetpile and stone combination 

containment structure. 

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create one 15.06 acre containment area for dredged material. A 15.06 acre 

containment area would be able to contain approximately 144,100 cubic yards of 

dredged material. The sheetpile would be driven into the bottom with a resulting top of 

sheetpile elevation 4 feet above the sea floor. The outside perimeter of the sheetpile 

Figure 5.02. Typical Sheetpile & Stone Cross Section for Alternatives 2 – 9.
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wall would be protected with NCDOT Class 2 armor stone (9”-23”). Bedding stone for 

the armor stone would be NCDOT Class B stone (5”-12”). Dredged material from 

maintenance dredging of the federal navigation channel would be pumped into the 

containment area. The dredged material would be covered with NCDOT Class A stone 

(2”-6”) and oyster shell to provide habitat for establishment of oysters. 

Alternative 4 - one 9.7 acre site with sheetpile and stone combination 

containment structure.

 

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create one 9.7 acre containment area for dredged material. A 9.7 acre containment 

area would be able to contain approximately 90,800 cubic yards of dredged material. 

The sheetpile would be driven into the bottom with a resulting top of sheetpile elevation 

4 feet above the sea floor. The outside perimeter of the sheetpile wall would be 

protected with NCDOT Class 2 armor stone (9”-23”). Bedding stone for the armor stone 

would be NCDOT Class B stone (5”-12”). Dredged material from maintenance dredging 

of the federal navigation channel would be pumped into the containment area. The 

dredged material would be covered with NCDOT Class A stone (2”-6”) and oyster shell 

to provide habitat for establishment of oysters. 

Alternative 5 – Two 9.7 acre sites with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create two 9.7 acre containment areas for dredged material. Two A 9.7 acre 

containment areas would be able to contain a total of approximately 181,600 cubic 

yards of dredged material. The two separate containment areas would be constructed 

in close proximity of each other. The sheetpile would be driven into the bottom with a 

resulting top of sheetpile elevation 4 feet above the sea floor. The outside perimeter of 

the sheetpile wall would be protected with NCDOT Class 2 armor stone (9”-23”). 

Bedding stone for the armor stone would be NCDOT Class B stone (5”-12”). Dredged 

material from maintenance dredging of the federal navigation channel would be pumped 

into the containment areas. The dredged material would be covered with NCDOT Class 

A stone (2”-6”) and oyster shell to provide habitat for establishment of oysters. 

Alternative 6 – One 5.07 acre site with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create one 5.07 acre containment area for dredged material. A 5.07 acre containment 

area would be able to contain approximately 45,500 cubic yards of dredged material. 

The sheetpile would be driven into the bottom with a resulting top of sheetpile elevation 

4 feet above the sea floor. The outside perimeter of the sheetpile wall would be 

protected with NCDOT Class 2 armor stone (9”-23”). Bedding stone for the armor stone 

would be NCDOT Class B stone (5”-12”). Dredged material from maintenance dredging 

of the federal navigation channel would be pumped into the containment area. The 
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dredged material would be covered with NCDOT Class A stone (2”-6”) and oyster shell 

to provide habitat for establishment of oysters. 

Alternative 7 – Two 5.07 acre sites with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create two 5.07 acre containment areas for dredged material. Two 5.07 acre 

containment areas would be able to contain a total of approximately 91,000 cubic yards 

of dredged material. The two separate containment areas would be constructed in 

close proximity of each other. The sheetpile would be driven into the bottom with a 

resulting top of sheetpile elevation 4 feet above the sea floor. The outside perimeter of 

the sheetpile wall would be protected with NCDOT Class 2 armor stone (9”-23”). 

Bedding stone for the armor stone would be NCDOT Class B stone (5”-12”). Dredged 

material from maintenance dredging of the federal navigation channel would be pumped 

into the containment areas. The dredged material would be covered with NCDOT Class 

A stone (2”-6”) and oyster shell to provide habitat for establishment of oysters. 

Alternative 8 – Three 5.07 acre sites with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create three 5.07 acre containment areas for dredged material. Three 5.07 acre 

containment areas would be able to contain a total of approximately 136,500 cubic 

yards of dredged material. The three separate containment areas would be constructed 

in close proximity of each other. The sheetpile would be driven into the bottom with a 

resulting top of sheetpile elevation 4 feet above the sea floor. The sheetpile would be 

driven into the bottom to provide a 4-foot height above the sea floor. The outside 

perimeter of the sheetpile wall would be protected with NCDOT Class 2 armor stone (9”-

23”). Bedding stone for the armor stone would be NCDOT Class B stone (5”-12”). 

Dredged material from maintenance dredging of the federal navigation channel would 

be pumped into the containment areas. The dredged material would be covered with 

NCDOT Class A stone (2”-6”) and oyster shell to provide habitat for establishment of 

oysters. 

Alternative 9 – Four 5.07 acre sites with sheetpile and stone combination 

containment structure.

This alternative would involve creation of oyster habit by using a composite sheetpile to 

create four 5.07 acre containment areas for dredged material. Four 5.07 acre 

containment areas would be able to contain a total of approximately 182,000 cubic 

yards of dredged material. The four separate containment areas would be constructed 

in close proximity of each other. The sheetpile would be driven into the bottom with a 

resulting top of sheetpile elevation 4 feet above the sea floor. The outside perimeter of 

the sheetpile wall would be protected with NCDOT Class 2 armor stone (9”-23”). 

Bedding stone for the armor stone would be NCDOT Class B stone (5”-12”). Dredged 
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material from maintenance dredging of the federal navigation channel would be pumped 

into the containment areas. The dredged material would be covered with NCDOT Class 

A stone (2”-6”) and oyster shell to provide habitat for establishment of oysters. 

Alternative 10 – one 18.6 acre site with 4-foot stone sill containment structure.

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create one 18.6 acre containment area 

for dredged material. An 18.6 acre containment area would be able to contain 

approximately 178,600 cubic yards of dredged material. The core portion of the 

containment structure would be constructed of NCDOT Class B Stone (5”-12”). 

Dredged material from maintenance dredging of the federal navigation channel would 

be pumped into the containment area. The dredged material would be covered with 

NCDOT Class A stone and oyster shell to provide habitat for establishment of oysters. A 

typical cross section is shown in Figure 5.03.

Alternative 11 – one 15.06 acre site with 4-foot stone sill containment structure.

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create one 15.06 acre containment 

area for dredged material. A 15.06 acre containment area would be able to contain 

approximately 143,290 cubic yards of dredged material. The core portion of the 

containment structure would be constructed of NCDOT Class B Stone (5”-12”). 

Dredged material from maintenance dredging of the federal navigation channel would 

be pumped into the containment area. The dredged material would be covered with 

NCDOT Class A stone and oyster shell to provide habitat for establishment of oysters. 

Figure 5.03. Typical Stone Cross Section for Alternatives 10 – 17.
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Alternative 12 – one 9.7 acre site with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create one 9.7 acre containment area 

for dredged material. A 9.7 acre containment area would be able to contain 

approximately 90,100 cubic yards of dredged material. The core portion of the 

containment structure would be constructed of NCDOT Class B Stone (5”-12”). 

Dredged material from maintenance dredging of the federal navigation channel would 

be pumped into the containment area. The dredged material would be covered with 

NCDOT Class A stone and oyster shell to provide habitat for establishment of oysters. 

Alternative 13 – Two 9.7 acre sites with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create two 9.7 acre containment areas 

for dredged material. Two 9.7 acre containment areas would be able to contain a total 

of approximately 180,200 cubic yards of dredged material. The two separate 

containment areas would be constructed in close proximity of each other. The core 

portion of the containment structures would be constructed of NCDOT Class B Stone 

(5”-12”). Dredged material from maintenance dredging of the federal navigation 

channel would be pumped into the containment areas. The dredged material would be 

covered with NCDOT Class A stone and oyster shell to provide habitat for 

establishment of oysters. 

Alternative 14 – One 5.07 acre site with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create one 5.07 acre containment area 

for dredged material. A 5.07 acre containment area would be able to contain 

approximately 45,000 cubic yards of dredged material. The core portion of the 

containment structure would be constructed of NCDOT Class B Stone (5”-12”). 

Dredged material from maintenance dredging of the federal navigation channel would 

be pumped into the containment area. The dredged material would be covered with 

NCDOT Class A stone and oyster shell to provide habitat for establishment of oysters. 

Alternative 15 – Two 5.07 acre sites with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create two 5.07 acre containment 

areas for dredged material. Two 5.07 acre containment areas would be able to contain 

a total of approximately 90,000 cubic yards of dredged material. The two separate 

containment areas would be constructed in close proximity of each other. The core 

portion of the containment structures would be constructed of NCDOT Class B Stone 

(5”-12”). Dredged material from maintenance dredging of the federal navigation 

channel would be pumped into the containment areas. The dredged material would be 
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covered with NCDOT Class A stone and oyster shell to provide habitat for 

establishment of oysters. 

Alternative 16 – Three 5.07 acre sites with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create three 5.07 acre containment 

areas for dredged material. Three 5.07 acre containment areas would be able to 

contain a total of approximately 135,000 cubic yards of dredged material. The three 

separate containment areas would be constructed in close proximity of each other. The 

core portion of the containment structures would be constructed of NCDOT Class B 

Stone (5”-12”). Dredged material from maintenance dredging of the federal navigation 

channel would be pumped into the containment areas. The dredged material would be 

covered with NCDOT Class A stone and oyster shell to provide habitat for 

establishment of oysters. 

Alternative 17 – Four 5.07 acre sites with 4-foot stone sill containment structure

This alternative would involve creation of oyster habitat by constructing a stone sill 

made of NCDOT Class 2 armor stone (9”-23”) to create four 5.07 acre containment 

areas for dredged material. Four 5.07 acre containment areas would be able to contain 

a total of approximately 180,000 cubic yards of dredged material. The four separate 

containment areas would be constructed in close proximity of each other. The core 

portion of the containment structures would be constructed of NCDOT Class B Stone 

(5”-12”). Dredged material from maintenance dredging of the federal navigation 

channel would be pumped into the containment areas. The dredged material would be 

covered with NCDOT Class A stone and oyster shell to provide habitat for 

establishment of oysters. 
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5.4 Comparison of Alternatives

5.4.1 “Base Plan” Costs

Under the Section 204 Authority, costs of beneficial use of sediment projects are limited 

solely to construction costs that are in excess of the Base Plan (normal dredging costs 

without the project). As a result, the costs used for evaluation and comparison 

purposes are the incremental costs of the potential ecosystem restoration plans over 

the cost associated with disposing of the sediments as described in the Base Plan. In 

the case of Manteo, Old House Channel, the costs used for evaluation/comparison 

purposes are the costs by which the construction costs exceed the cost of dredging of 

materials from Old House Channel (Range 2) and disposal on the designated disposal 

area (typically either Wells, Parnell, or island MN). Since there are different quantities 

of dredged material associated with different alternatives, certain alternatives will be 

compared to a different “base plan” cost. Each of these different plans will include the 

costs of mob/demob, dredging of the sediments, and transportation and disposal of the 

sediments at the designated disposal area. These costs were developed by the 

Wilmington District Cost Engineering Team based on Regional Sediment Management 

(RSM) system data from the most recent dredging event at Manteo Old House Channel

(2008). The lowest bidder cost in 2008 was $6.34 per cubic yard (CY). Using 

escalation rates from October 2008 to October 2014 gives a rate of 105.4%. This 

inflates the price to $6.68. Adjusting fuel costs another $0.32 would bring the costs for 

dredging to $7.00 per CY. This figure was used to estimate the base plan costs below. 

The “base plan” costs for each alternative are shown in Table 5.04.

 

 

*Cubic yards for each set of alternatives in table are rounded for grouping purposes. 

Base Plan Costs for Manteo 204

Alternative Cubic yards* Total Costs

Alternatives 

2,5,9,10,13,&17 180,000 $1,260,000

Alternatives 3&11 144,000 1,008,000

Alternatives 4&12 90,000 630,000

Alternatives 6&14 45,000 315,000

Alternatives 7&15 91,000 637,000

Alternatives 8&16 135,000 945,000

Table 5.04. Base Plan Costs for Manteo, Old House Channel, NC
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5.4.2 Costs of Alternatives

Table 5.05. Costs of Alternatives

Alternative Estimated Cost Average Annual Cost

No Action $0.00

2 $9,492,913 $459,573.00

3 $8,221,938 $398,042.00

4 $6,202,513 $300,277.00

5 $11,286,353 $545,526.00

6 $4,304,592 $208,395.00

7 $7,473,198 $361,794.00

8 $10,641,804 $515,193.00

9 $13,810,410 $668,192.00

10 $7,024,596 $340,0767.00

11 $5,999,991 $290,473.00

12 $4,425,449 $214,146.00

13 $7,718,010 $373,646.00

14 $3,024,840 $146,439.00

15 $4,916,793 $238.033.00

16 $6,804,659 $329,429.00

17 $8,695,469 $420,967.00

5.4.3 Ecological Output Analysis of Alternatives

Introduction. Environmental Benefits Assessment (EBA) is used to measure the 

increase in both the quality and quantity of a targeted ecosystem due to various 

proposed restoration measures and alternatives at a site. For the Manteo 204 study, 

quality was measured in terms of a Habitat Suitability Index (HSI). The HSI is multiplied 

by the number of acres being restored in order to generate a “Habitat Unit (HU)” as 

output. The greater the number of Habitat Units the greater the ecological benefit. 

The following sections contain detailed description of the application of the Oyster HEP 

model.

Habitat Evaluation Procedure (HEP). Estuarine reefs were evaluated using a USFWS 

Habitat Evaluation Procedure (HEP). The Eastern oyster (Crassostrea virginica) was 

the target species since a healthy oyster population is considered a keystone indicator 

of the ecological health of the estuary (NCDMF, 2001 and Frankenberg, 1995). Oysters 
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are ecosystem engineers (Jones et al., 1994) where oyster growth and recruitment is 

required for reef sustainability and expansion. 

Habitat Suitability Index (HSI) Model. The Habitat Suitability Index (HSI) Model: Gulf 

of Mexico American Oyster developed by the US Fish and Wildlife Service (Cake, 1983) 

was applied (American oyster is synonymous with Eastern oyster). This model was 

developed for the Gulf of Mexico with application in Atlantic Coast habitats south of 

Cape Hatteras. The oyster habitat of the Pamlico Sound where the project would be 

located area is similar to that of the Gulf of Mexico, in that it supports subtidal oysters 

(Eastern oyster (Crassostrea virginica)) in waters that are less than 33 feet deep with a 

small tide range. This site is 35 miles north of Cape Hatteras so oyster life requisites 

measured by model variables were confirmed as appropriate for this analysis by review 

of literature regarding Atlantic coast oyster populations (Kennedy et al., 1996). Oyster 

sampling by NC State University at nearby (< 5 miles) NCDMF Crab Hole Sanctuary 

further confirm high potential for oyster establishment in the project vicinity.

Variables and Formulas. This HSI model has a larval and an adult component and 

assesses 6 variables to define Habitat suitability. The variables measure reef structure, 

water column conditions, and oyster abundance to determine site suitability for both 

larvae (Table 5.06, Variables 1-3) and adult oysters (Table 5.07, Variables 4-6). 

Habitat suitability was calculated as explained below. The model specifically measures 

habitat suitability for oysters; however, for this application oysters are considered a 

keystone species supporting, and therefore serving as an indicator of, the wide array of 

estuarine functions. One associated function is support of fishery resources on and in 

subtidal bottoms adjacent to the reef structure. Studies have shown that significant 

increases in the numbers of fish and species richness would also occur in adjacent soft 

bottom areas extending 50 -100 meters away from the reef (dos Santos et al. 2010). 

Therefore a conservative 50m perimeter service area, to be demarcated by corner 

buoys and protected by sanctuary designation is included as a component of this 

project. As an established oyster sanctuary, the reef and adjacent (service area) soft 

bottom habitats and resident fauna, would be protected from future harvest and bottom 

disturbance. The HSI of this area, as a function of proximity of the reef, is assumed to 

be equal to that of the reef immediately adjacent and diminishing to a conservative 

theoretical 0, at a distance 50 meters away from the toe of the reef structure.. For this 

analysis the average HSI of the reef service area is calculated as Service Area HSI = 

(HSI for the reef adjacent parameter + HSI at 50m (0))/2 (Cake, 1983).

 
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 Table 5.06. HSI Variables to Assess Suitability for Oyster Larvae.

HSI Variables for Suitability for Oyster Larvae

FUNCTION VARIABLE DATA 

SOURCE HSI Graph (Cake 1983)

Support 

larval 

attachment

V1 Percent 

suitable 

cultch

Existing 

Condition 

Side ERDC 

Scan Survey 

Report 

(2009) Future 

Conditions 

from design

Water 

quality 

support for 

oyster 

larvae

V2 Mean 

summer 

salinity (ppt)

NCSU Crab 

Hole 

Monitoring 

Data 2006-

2008 &NC 

Shellfish 

Sanitation 

Oregon Inlet 

Fishing 

Center 

Monitoring 

Data 2006-

2010

Biological 

support for 

larvae

V3 Mean 

abundance 

of living 

oysters /M2

NCSU Crab 

Hole 

Monitoring 

Data 2006-

2008 

 
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Table 5.07. HSI Variables to Assess Suitability for Adult Oysters.

The HSI, representing habitat quality, was multiplied by the available habitat quantity, for reef 

service area to determine output measured in Functional Units. 

1. CIL Larvae HSI =(V1 X V2 X V3)

1/3 if V3=0 (V1

X V2) 1/2

2. CIA (Adult HSI) =(V4 X V5 X V6)

1/3 if V6 =0 CIA= 0 

3. Oyster HSI If CIA is<CIL HSI=CIA, if CIA>CIL HSI =(CIA X CIL)

1/2 

Service Area HSI Calculation: 

Service Area HSI = (HSI for the reef adjacent perimeter + HSI for the +50m perimeter)/2. 

HSI Variables for Suitability for Adult Oysters

FUNCTION VARIABLE DATA SOURCE HSI Graph

Water column 

support adult 

oysters 

V4 Historic mean 

salinity (ppt)

NCSU Crab Hole 

Monitoring Data 

2006-2008 &NC 

Shellfish 

Sanitation Oregon 

Inlet Fishing 

Center Monitoring 

Data 2006-2010

Avoidance of 

killing 

conditions

V5 Frequency of 

killing events/period 

of record)

NCSU Crab Hole 

Monitoring Data 

2006-2008 &NC 

Shellfish 

Sanitation Oregon 

Inlet Fishing 

Center Monitoring 

Data 2006-2010

Structural 

support for 

adult oysters

V6 Substrate 

firmness (hard or 

soft). Areas >80% 

sand = 0

Existing and 

Without Project 

Geotechnical 

Appendix With 

Project 

Conditions from 

Proposed Design 
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Existing and Future Without Project Conditions. The area proposed for reef 

development is existing sandy estuarine bottom. Existing deep water sandy bottoms 

lack suitable cultch and cannot support oyster reefs without the addition of structure and 

cultch. The HSI model provides an index of 0 if the bottom substrate is composed of 

80% or more sand. The existing absence of shell bottom and sandy bottom sediment in 

the project foot print has been confirmed by side scan survey and sediment analysis. 

No plans exist to build reefs in this area; therefore the future condition without a Federal 

project is status quo. Existing sandy soft bottom habitats are currently remote (beyond 

100m) to reef structure and currently do not function as a reef and soft bottom complex. 

The sites lack hard structure and are subjected to reoccurring impacts to benthic 

resources from trawling. These bottoms currently have no potential to establish reef 

habitat and were considered to generate 0 benefits under the without project condition. 

Computation of Habitat Suitability Index. The proposed project includes the 

construction of new high output reef areas that would be identified by a series of buoys 

for designation as a sanctuary. As sanctuary, these sites would be managed by NCDMF 

to preclude oyster harvest and trawling. Recreational fin-fishing by hook and line is 

allowed. This measure would expand on an existing successful practice that has 

developed a complex including nine Oyster Sanctuaries throughout the Pamlico Sound. 

This site is located between two existing NCDMF sanctuaries including 1) Croatan 

Sound Sanctuary an 8 acre sanctuary established in 1996, including 1,800 tons of 

riprap, oyster shells surf clam shells and limestone marl and, 2) Crab Hole a 30.5 acre 

sanctuary including 37, 00 tons of riprap that are within a 3 mile radius of the proposed 

site and should be benefited by an additional supply of larvae once the new reefs 

become populated by oysters.

The site location was optimized considering pumping distance from the Old House 

Channel, and bottom conditions to assure foundational stability and to avoid existing 

biological resources. Mud bottoms (preferred crab harvest areas), SAV and existing 

shell bottoms were avoided. The proposed location is shown in Figure 5.01. It is 

assumed that any location within this identified area would have equal suitability for 

oyster growth and sustainability and only one HSI for the existing, future without, and 

future with condition was calculated.

 
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Table 5.08. HSI Computations based on HEP.

HSI Computations Based on HEP

USFWS OYSTER HSI 

MODEL (CAKE, 1983)

V1 Substrate IndexV2 Mean Sum Salinity Index Values V3, Gregarious Factor (density)CIL Larvae HSI =(V1 X V2 X V3)1/3 if V3=0 (V1 X 

V2) 1/2

V4 Hist Mean Sal Index calculated by V5 Mean-Kill Freq Index(Tt V1)V6 Substrate Firmness* CIA =(V4 X V5 X V6)1/3 if V6 =0 CI

A= 0

Oyster HSI If CI

A is<CIL HSI=CI

A, if 

CIA<CIL HSI =(CI

A X CIL)1/2 

Existing Condition 0.0 1.0 0.0 0.0 1.0 1.0 0.0 1.0 0.0

Future With Reef 

Construction 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Future Without 0.0 1.0 0.0 0.0 1.0 1.0 0.0 1.0 0.0

Notes:* existing and future without condition >80% sand =0 

Construction of new sanctuary reefs would add suitable cultch (V1); provide a firm rock 

layer where bare sandy bottom currently exists (V6). Variable V3, oyster density, will be 

assumed to be equal to nearby reference reefs by year 3. Benefits realized by 

construction of new sanctuary reefs will not be fully realized until year 3 at which time 

oyster recruitment and growth is expected to equal that of natural reefs located in the 

same cell. Habitat data for reference reefs are shown in Reference 3. FIs were 

annualized as shown in Reference 4. For simplicity, benefits are assumed to increase 

linearly until year 3. 

Benthic Conditions Evaluated. Two potential bottom conditions were evaluated to 

determine suitability for oyster growth including (1) oyster reef (with project condition) 

and (2) sandy bottoms in the vicinity < 50M of new reef structure (with project condition). 

Future without project conditions over the 50 year period of analysis is status quo, 

where unprotected sandy bottom would persist. Under with project conditions sandy 

bottoms would be converted to functioning reefs with HSI equal to 1.0 or reef service 

area HSI =0.5 after a 3 establishment period. 

Oyster Reefs. HSI for reef habitat in the proposed reef construction area would be 1.0, 

indicating ideal condition for oyster establishment and growth. These sites would have 

a hard structure that elevates the reef tops reducing potential exposure to hypoxia and 
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would be protected from harvest. The benefits of reef habitat are well documented 

(Deaton et al. 2010, Posey et al. 1999, Mann 2001, Peterson et al. 2003, Soniat et al. 

2004) as summarized below. The structural relief provided by high profile reefs and 

associated current upwelling would attract pelagic forage fish, and a shell covered 

surface provides habitat for resident species such as crabs, gobies, blennies and toad 

fish. These food resources would support transient fish such as bluefish and Spanish 

mackerel, anadromous fish, including striped bass, and important estuarine spawning 

sport fish, like red drum, would also use these food resources as they congregate in 

preparation for spawning. Juvenile sea bass, grouper and other ocean spawning 

estuarine dependent species, would also use these reefs as essential habitat during 

their exodus from estuarine nursery areas to the ocean. Abundant oysters support 

improved water quality by providing substantial filtering (Cresman et.al 2003), and 

provide improved habitat conditions supporting higher fish and fish food production. As 

an established oyster sanctuary, the reef and associated fauna would be protected from 

commercial harvest and bottom disturbance.

Sandy Bottoms Adjacent to Reefs. Once reefs are established adjacent estuarine 

bottoms within 50M of the reefs were determined to have an average HSI of 0.5. 

Studies have shown that significant increases in the numbers of fish and species 

richness would occur over adjacent bottom areas extending 50 - 100 meters away from 

the reef (dos Santos et al. 2010). As an established oyster sanctuary, the reef service 

area, bottom habitats and resident fauna, would be protected from commercial harvest 

and bottom disturbance.

Habitat Output. Two alternative designs and multiple size configurations were 

evaluated as listed below. Various reef designs and configurations alter the area of 

clutched or rock surface available for oyster attachment and the area of adjacent 

estuarine bottom that is enhanced by the reef proximity. The designs that maximize the 

reef and service area generate the most benefits. HUs and project costs were 

calculated for No Action and 2 containment scenarios, and 8 size combinations as 

shown below:

(1) No Action (Alt 1)

(2) Stone Containment:

Alt 10: One 18.60 Acre Reef

Alt 11: One 15.06 Acre Reef

Alt 12: One 9.70 Acre Reef

Alt 13: Two 9.70 Acre Reef Complex

Alt 14: One 5.07 Acre Reef

Alt 15: Two 5.07 Acre Reef Complex

Alt 16: Three 5.07 Acre Reef Complex

Alt 17: Four 5.07 Acre Reef Complex 

(3) Sheetpile Containment:

Alt 2: One 18.60 Acre Reef 

Alt 3: One 15.06 Acre Reef

Alt 4: Once 9.70 Acre Reef

Alt 5: Two 9.70 Acre Reef Complex
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Alt 6: One 5.07 Acre Reef

Alt 7: Two 5.07 Acre Reef Complex

Alt 8: Three 5.07 Acre Reef Complex

Alt 9: Four 5.07 Acre Reef Complex 

Table 5.09. Oyster Areas and Outputs for Various Alternatives. 

ALTERNATIVES OYSTER REEF SERVICE AREA OUTPUT

HAB INDEX ACRES HAB INDEX ACRES HUs AAHUs

Alt 1 0.0 0.0 0.0 0.0 0.0 0.0

Alt 2 1.0 19.86 0.5 16.47 28.1 27.3

Alt 3 1.0 16.20 0.5 15.12 23.8 23.0

Alt 4 1.0 9.70 0.5 13.63 16.5 16.0

Alt 5 1.0 19.40 0.5 27.26 33.0 32.0

Alt 6 1.0 6.00 0.5 9.70 10.9 10.5

Alt 7 1.0 11.48 0.5 19.92 21.4 20.8

Alt 8 1.0 17.21 0.5 29.89 32.2 31.2

Alt 9 1.0 22.95 0.5 39.85 42.9 41.6

Alt 10 1.0 20.38 0.5 16.65 28.7 27.8

Alt 11 1.0 16.66 0.5 15.25 24.3 23.6

Alt 12 1.0 10.99 0.5 12.89 17.4 16.9

Alt 13 1.0 21.99 0.5 25.77 34.9 33.8

Alt 14 1.0 6.02 0.5 10.18 11.1 10.8

Alt 15 1.0 12.03 0.5 20.37 22.2 21.6

Alt 16 1.0 18.05 0.5 30.55 33.3 32.3

Alt 17 1.0 24.07 0.5 40.73 44.4 43.1

For each alternative, an Average Annual Habitat Unit (AAHU) was calculated (Table 

5.09). AAHU are calculated by determining Habitat Units for each project year, adding 

these together, and dividing by the project life (50 years). The total AAHU benefit for 

oysters is the difference between the AAHU calculated for that alternative (with project)

and the AAHU calculated for the no action alternative (without project). In all the 

alternatives evaluated, the without project condition was 0.

Note: (Reef Hab Index x Acres) + (Service Area Hab Index x Acres) = HUs
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5.4.4 Cost Effectiveness/Incremental Cost Analysis

For ecosystem restoration planning, where traditional benefit-cost analysis is not 

possible because costs and benefits are expressed in different units, cost effectiveness 

analyses offer plan evaluation approaches that are consistent with the P&G paradigm. 

Cost effectiveness analyses are conducted to ensure that the least cost plans are 

identified for each possible level of ecosystem restoration output; and that for any level 

of investment, the maximum level of output is identified.

In the absence of a common measurement unit for comparing the non-monetary 

benefits with the monetary costs of ecosystem restoration plans, cost effectiveness 

analyses are valuable tools to assist in decision-making. The results of the analyses 

permit decision-makers to progressively compare alternative levels of ecosystem 

restoration outputs.

Methodology. Data for initial construction/implementation, land acquisition, monitoring, 

and periodically recurring costs for OMRR&R (operation, maintenance, repair, 

replacement, and rehabilitation), have been developed through engineering design and 

cost estimation, and real estate appraisal efforts. Details of that data development are 

explained and discussed elsewhere in this report. The main issues requiring economic 

evaluation attention include present worth calculations, price levels, and timing of 

project spending.

Costs represent the difference between conditions without any plan (the “base 

condition”, or “without-project condition”) and with a plan or alternative. For purposes of 

this report and analysis, NER costs (National Environmental Restoration Costs, as 

defined by Federal and Corps of Engineers policy), are expressed in 2012 price levels, 

and are based generally on costs estimated to be incurred over a 50 year period of 

analysis. Costs of a plan represent the value of goods and services required to 

implement and operate/maintain the plan. 

The timing of a plan’s costs is important. Construction and other initial implementation 

costs cannot simply be added to periodically recurring costs for project operation, 

maintenance, and monitoring. Also, construction costs incurred in a given year of the 

project can’t simply be added to construction costs incurred in other years if meaningful 

and direct comparisons of the costs of the different alternatives are to be made. A 

common practice of equating sums of money across time with their equivalent at an 

earlier single point in time is the process known as discounting. Through this 

mathematical process, which involves the use of an interest rate (or discount rate) 

officially prescribed by Federal policy for use in water resource planning analysis 

(currently set at 4.0% per year), the cost time streams of each alternative are 

mathematically translated into a present worth value. This present worth value, 

calculated for this study as of the beginning of the period of analysis, can then be 

directly and meaningfully compared between the plans being considered in this study. 

An annual value, equivalent to the present worth, can also be computed for the 50 year 
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period of analysis. This average annual value represents an equivalent way of 

expressing the costs of a plan. The various costs estimated to be incurred over time to 

put each plan into place and keep it going will be computed and expressed as both a 

present worth value and an average annual equivalent value.

Cost Effective Alternative Selection. Cost effectiveness analysis begins with a 

comparison of the costs and outputs of alternative plans to identify the least cost plan 

for every possible level of output considered. The resulting least cost alternative plans 

are then compared to identify those that would produce greater levels of output at the 

same cost, or at a lesser cost, as other alternative plans. Alternative plans identified 

through this comparison are the cost effective alternative plans. Next, the cost effective 

alternative plans are compared to identify the most economically efficient alternative 

plans, that is, the “Best Buy” alternative plans that would produce the largest output for 

the associated cost. Finally, the additional costs for the additional amounts of output 

(“incremental cost”) produced by the Best Buy alternative plans are calculated. The 

results of all the calculations and comparisons of costs and outputs provide a basis for 

addressing the decision question of if the additional outputs worth the costs incurred to 

achieve them.
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Table 5.10. Cost and Performance Summary for Plan Selection (in order of ascending habitat output) 

COST AND PERFORMANCE SUMMARY USED IN COST

EFFECTIVENESS FOR PLAN SELECTION,

Manteo 204

Alternative # 

and 

Description Estimated

Cost

Average 

Annual 

Cost

Average 

Annual 

Habitat 

Units

Cost 

Per 

Habitat 

Unit

Cost 

Effective

?

Best 

Buy?

Cost 

Within 

CAP 

limit?

1 No Action $0.00 0.0 $0 Yes Yes Yes

6 Sheet Pile 5.07 $4,304,592 $208,395 10.5 $19,847 No No Yes

14 Stone 5.07 $3,024,840 $146,439 10.8 $13,559 Yes No Yes

4 Sheet Pile 9.7 $6,202,513 $300,277 16 $18,767 No No Yes

12 Stone 9.7 $4,425,449 $214,146 16.9 $12,677 Yes No Yes

7 Sheet Pile 

2X5.07 $7,473,198 $361,794 20.8 $17,394 No No No

13 Stone 2X5.07 $4,916,793 $238,033 21.6 $11,020 Yes No Yes

3 Sheet Pile 

15.06 $8,221,938 $398,042 23 $17,306 No No No

11 Stone 15.06 $5,999,991 $290,473 23.6 $12,308 Yes No Yes

2 Sheet Pile 18.6 $9,492,913 $459,573 27.3 $16,834 No No No

10 Stone 18.6 $7,024,596 $340,076 27.8 $12,233 No No Yes

8 Sheet Pile 

3X5.07 $10,641,804 $515,193 31.2 $16,513 Yes No No

5 Sheet Pile 

2X9.7 $11,286,353 $545,526 32 $17,047 No No No

16 Stone 3X5.07 $6,804,659 $329,429 32.3 $10,199 Yes No Yes

13 Stone 2X9.7 $7,718,010 $373,646 33.8 $11,055 Yes No No

9 Sheet Pile 

4X5.07 $13,810,410 $668,192 41.6 $16,062 No No No

17 Stone 4X5.07 $8,695,469 $420,967 43.1 $9,767 Yes Yes No
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Figure 5.04. Planning Set Cost and Output

Incremental Cost Analysis. This section presents the results of incremental cost 

analysis for the Manteo 204 alternative plans for the optimization of the site. All the cost 

effective plans are arrayed by increasing output to clearly show changes in cost (i.e., 

increments of cost) and changes in output (i.e., increments of output) of each cost 

effective alternative plan compared to the Without Plan condition. The plan with the 

lowest incremental costs per unit of output of all plans is the first Best Buy plan. After 

the first Best Buy plan is identified, all larger cost effective plans are compared to the 

first Best Buy plan in terms of increases in (increments of) cost and increases in 

(increments of) output. 
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Table 5.11. Results of Incremental Cost Analysis

RESULTS OF INCREMENTAL COST ANALYSIS:

BEST BUY PLANS ARRAYED BY INCREASING OUTPUT

FOR COMBINED HABITAT (ALL PLANS)

Plan

Average

Annual

Cost

Output

Average

Cost Per

Output

Incremental

Average

Annual Cost

Incremental 

Output

Incremental

Cost Per

Output

No 

Action $0 0 $0 $0 0 $0

Stone 

4X5.07 $420,967 43.1 $9,767 $420,967 43.1 $9,767

Figure 5.05. Planning Set Incremental Cost and Output
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5.5 Screening of Alternative Plans

The alternatives considered in this analysis were screened based on a number of 

factors, all of which are discussed below.

Completeness, Effectiveness, Efficiency, and Acceptability. Completeness, 

Effectiveness, Efficiency, and Acceptability are the four evaluation criteria specified that 

the USACE uses in the screening of alternative plans (USACE P&G Section 1.6.2(c)). 

Alternatives considered in any planning study, not just ecosystem restoration studies, 

should meet minimum subjective standards of these criteria in order to qualify for further 

consideration and comparison with other plans.

Completeness. A plan must provide and account for all necessary investments or 

other actions needed to ensure the realization of the planned restoration outputs. This 

may require relating the plan to other types of public or private plans if these plans are 

crucial to the outcome of the restoration objective. Real estate, operations and 

maintenance, monitoring, and sponsorship factors must be considered. Where there is 

uncertainty concerning the functioning of certain restoration features and an adaptive 

management plan has been proposed, it must be considered for in the plan. 

Of the alternatives considered in detailed analysis, all directly address the identified 

problem of the decline of oyster habitat in Pamlico Sound. Those alternatives 

consisting of larger acreages of restored area would provide greater benefit. Successful 

resource reference areas in the project vicinity add assurance that the benefits 

attributed to these alternatives in this analysis will actually be realized. For this study, 

an adaptive management plan is described in Section 6.3.

Effectiveness. Effectiveness is the extent to which an ecosystem restoration plan 

alleviates the specified problems and achieves the specified opportunities. The costeffectiveness of the array of alternatives was analyzed using IWR-Plan software. 

Alternatives 11, 12, 13, 14, 15, 16, and the No-Action plan were identified as being 

effective in terms of cost per benefit.

Efficiency. Efficiency is the extent to which an alternative plan is the most cost 

effective means of alleviating the specified problems and realizing the specified 

opportunities. The problem identified and opportunities that may be realized under this 

Section 204 study are associated with the future without project condition of lack of 

oyster habitat in the project vicinity, and an opportunity to contribute to the connectivity 

of a self-sustaining network of oyster reefs in Pamlico Sound, NC as expressed by the 

North Carolina Oyster Restoration Steering Committee’s northern workgroup. As 

discussed in Section 5.4.4, Alternative 17 and the no-action plan were designated as 

Best Buy alternatives. As a result, these are the alternatives that provide the most 

“bang for the buck”, and therefore are the most efficient alternatives. However, the noaction does not address the identified problem or opportunities that exist. Additionally, 

Alternative 17 exceeds the federal cost-share limit of the Section 204 authority. 
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Therefore, the most cost-efficient alternative identified by IWR-Plan that is within the 

cost constraints of the authority was identified as Alternative 16. 

Acceptability. An ecosystem restoration plan should be acceptable to state and 

Federal resource agencies, local governments and the public, and compatibility with 

existing laws, regulations, and public policies. A recommended plan must be 

acceptable to the non-Federal cost-sharing partner. However, this does not mean that 

the recommended plan must be the locally preferred plan. All of the alternatives under 

consideration are in concert with state and Federal agency views in that oyster habitat 

in Pamlico Sound should be addressed in order to restore and preserve the ecological 

integrity of the Albemarle-Pamlico National Estuary system of North Carolina. A 

recommended plan should also fall within the cost limitation of the Section 204

Authority. The best buy plan, Alternative 17, exceeds the cost limitations. Alternatives 

11, 12, 13, 14, 15, 16, and the No-Action plan were identified as being effective in terms 

of cost per benefit and were within cost limitations of the Authority. 

5.6 Resource Significance 

This section provides a qualitative evaluation and summary of the alternative impacts to 

significant resources. Along with information from cost effectiveness and incremental 

costs analyses, information on the significance of ecosystem outputs will help determine 

whether a proposed environmental investment is worth the cost. The significance of the 

Manteo, Old House Channel, NC restoration outputs is herein recognized in three 

categories: Institutional, Public, and/or Technical. 

5.6.1 Institutional Significance. 

Significance based on institutional recognition means that the importance of an 

environmental resource is acknowledged in the laws, adopted plans, and other policy 

statements of public agencies, tribes, or private groups. Sources of institutional 

recognition include public laws, executive orders, rules and regulations, treaties, and 

other policy statements of the Federal Government; plans, laws, resolutions, and other 

policy statements of states with jurisdiction in the planning area; laws, plans, codes, 

ordinances, and other policy statements of regional and local public entities with 

jurisdiction in the planning area; charters, bylaws, and other policy statements of private 

groups.

The Albemarle-Pamlico Sound was designated by Congress as an “estuary of national 

significance” in 1987. Oysters have been recognized as a keystone species of that 

ecosystem (Street et al. 2005; Peterson et al. 2003; NCDMF 2009). The North Carolina 

Division of Marine Fisheries (NCDMF) has designated the Eastern Oyster (Crassostrea 

virginica) as a species of “Concern” due to long term decline caused by overharvesting 

and habitat disturbances (NCDMF 2010). Oyster restoration is a high priority for the 

State of North Carolina as expressed in the Blue Ribbon Report (Frankenburg 1995). 

Restoration of oysters in North Carolina is also a national goal of the US EPA’s 

Albemarle-Pamlico Sound National Estuary Program 
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(source:www.carteret.edu/aqu/cogp/). The NC Oyster Restoration Steering Committee 

(NCORSC), comprised of various resource agencies and private organizations, has 

identified the project vicinity as a priority area for restoration as part of an overall plan to 

create a self-sustaining network of oyster reefs in Pamlico Sound (Figure 5.06. Source: 

Notes from NE Oyster Work Group Meeting March 18, 2010). The NCORSC Northern 

Work Group also has a stated goal of “500 acres of new reef constructed and 

designated as sanctuaries by 2018”. The agencies and organizations that comprise the 

NCORSC include the NC Division of Coastal Management, The NC Division of Marine 

Fisheries, the NC Division of Water Quality, the NC Department of the Environment of 

Natural Resources, The NC Division of Environmental Health – Shellfish Sanitation 

Section, US Army Corps of Engineers, the North Carolina Coastal Federation, The 

Nature Conservancy, North Carolina Sea Grant Program, UNC Wilmington, NC State 

University, and UNC Chapel Hill Institute of Marine Sciences (NCCF, 2008). All of the 

alternatives in the final array under consideration work in concert with local, state, and 

Federal goals of oyster restoration in North Carolina. 
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Figure 5.06. Priority Areas for Oyster Restoration, as recommended by the NCORSC Northern 

Workgroup (Includes Old House Channel). Source: North Carolina Oyster Work Group meeting 

notes, March 18, 2010.

5.6.2 Public Significance. 

Significance based on public recognition means that some segment of the general 

public recognized the importance of an environmental resource, as evidenced by 

people engaged in activities that reflect an interest or concern for that particular 

resource. Such activities may involve membership in an organization, financial 

contributions to resource-related efforts, and providing volunteer labor and 

correspondence regarding the importance of the resource.
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Organized public volunteer efforts are routinely underway throughout each year in 

North Carolina to restore oysters to North Carolina’s waters, both by recycling oyster 

shells for replacement in the water, and by support and membership in private 

organizations such as the North Carolina Coastal Federation which engage in active 

programs to restore the oyster population in North Carolina (NCCF, 2011). 

Figure 5.07. Volunteers Placing Oyster Shells in NC Waters to Create Reef. (source: NCCF)

5.6.3 Technical Significance. 

Significance based on technical recognition means that the resource qualifies as 

significant based on its “technical” merits, which are based on scientific knowledge or 

judgment of critical resource characteristics. Technical significance should be 

described in terms of one or more of the following criteria: scarcity, representation, 

status and trends, connectivity, and limiting habitat.

Significance of oysters as an important resource has been widely recognized and 

documented.

General. Oysters are good indicators of the overall health of an estuarine ecosystem 

(NCCF, 2008). They improve water quality and provide essential fish habitat and are a 

source of food for associated aquatic life. The irregular surfaces of oyster reefs provide 

fifty times the surface area of a similarly extensive flat bottom. Unique crevices provide 

good nursery habitat for a wide diversity of vertebrate and invertebrate organisms such 

as worms, snails, sea squirts, sponges, small crabs, and fishes. The small inhabitants 

of the subtidal reef community are the base of the food chain for a wide variety of 

predators. Oyster reefs are recognized by fisheries management agencies as vital 

habitat for certain commercially and recreationally important fish species and critical to 
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fisheries production (Street, 2005). A recent study, conducted through the North 

Carolina Sea Grant on the use of oyster reef habitat by economically valuable species,

suggests that restoring oyster reef habitat enhances fish production and potential 

harvest levels in North Carolina estuaries (Peterson and Grabowski, 2003). In addition, 

the presence of oyster reef sanctuaries provides a brooding stock which benefits the 

robustness of harvestable oyster reefs in adjacent waters (NCDMF, 2008 and Street et 

al., 2005).

Scarcity. Researchers estimate that 85% of oyster reefs world-wide have been lost 

(AFP 2011). In North Carolina, the eastern oyster has been given the stock status of 

Concern due to overharvesting and dredging practices (NCDMF 2010). Oyster 

landings in North Carolina are estimated to be only ten percent of what they were just 

over a century ago (Ortega & Sutherland, 1992; Street et al. 2005). All alternatives 

would contribute positively to reducing the scarcity of this resource.

Status and trends. Since the early 1900’s, North Carolina’s oyster harvests have 

declined 90 percent, with current estimates that only 50 percent of the population 

remains from the late 1800’s. With recognition of the importance of the oyster as a 

keystone species in ecosystem health, local, state and federal efforts have increased to 

restore oyster reef habitat. The NC Oyster Sanctuary Program has helped to increase 

biomass of oysters in and around the Pamlico Sound area (NCDMF 2010). Restoration 

is viewed as an essential tool to sustain long-term management of North Carolina’s 

oyster population. All alternatives would contribute to varying degrees in increasing the 

biomass of oysters in northern Pamlico Sound.

Connectivity. The NCORSC Northern workgroup has a goal of developing a network 

of self-sustaining oyster reefs in Albemarle-Pamlico National Estuary as described by 

the NCORSC’s Oyster Restoration and Protection Plan. Through modeling, historic 

data and knowledge of the area, NCORSC has identified the project vicinity as an area 

of need for re-establishment of oysters as part of an overall plan to create a selfsustaining network of oyster reefs in Pamlico Sound (Figure 5.06 Source: Notes from 

NE Oyster Work Group Meeting March 18, 2010). All alternatives would contribute to 

this network. Also, as a keystone species, oysters provide habitat to a wide variety of 

sea life.

5.7 The Ecosystem Restoration Plan

The criteria used to select the NER plan include all the evaluation criteria discussed 

above. Selecting the NER plan requires careful consideration of the plan that meets 

planning objectives and constraints and reasonably maximizes environmental benefits 

while passing tests of cost effectiveness and incremental cost analyses, significance of 

outputs, completeness, effectiveness, efficiency, and acceptability. Additional factors to 

consider include the following items:
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5.7.1 Partnership Context

This Beneficial Use of Dredged Material project was planned in cooperation with the 

State of North Carolina. The North Carolina Coastal Federation and the NC Oyster 

Restoration Steering Committee’s northern workgroup also provided valuable input. 

This project planning process included an opportunity for open comment to ensure the 

public has had opportunities to contribute.

5.7.2 Reasonableness of Costs

All costs associated with a plan were considered, and tests of cost effectiveness and 

incremental cost analysis have been satisfied for the alternatives analyzed. Cost 

estimates were based on the costs of transportation of construction materials to the site 

as well as project construction, and included contingency costs of 25%.

5.8 Plan Selection

5.8.1 The NER/Preferred Plan

The plan that reasonably maximizes net national ecosystem restoration benefits and is 

consistent with the Federal objective is identified as the NER plan. As mentioned in 

section 5.4.4, cost effectiveness/incremental cost analysis identified alternative 17

(stone sill, 4x5.07 acres) and the no-action plan as the best buy plans. Alternative 16 

(stone sill, 3x5.07 acres) was also identified as the most cost-efficient alternative that is 

within the cost constraints of the Section 204 authority. Since the no-action plan does 

not meet study objectives, and alternatives 16 and 17 both provide significant 

ecosystem restoration benefits in a cost-effective manner, the no-action plan was 

removed from consideration as the NER plan. As indicated in table 5.10, the 

incremental cost of implementing Alternative 17 is $9,767 per habitat unit. This is 

slightly less than the incremental cost of $10,199 per habitat unit for Alternative 16. The 

next most cost-effective plan is Alternative 11 with an incremental cost of $12,308 per 

habitat unit. Alternative 16 is the plan with the lowest cost per unit of habitat ($10,199) 

that is within the cost constraints of the Section 204 Authority. Therefore, Alternative 

16 is selected as the NER plan and the federally recommended plan.

5.8.2 NED/Optimum Tradeoff Plan

Because all alternatives considered address ecosystem restoration of the Old House 

Channel area rather than national economic development, no plans have been 

identified as being the NED plan. Additionally, there is no optimum trade off plan as 

each of the alternatives considered only address ecosystem restoration.
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5.8.3 Locally Preferred Plan

There is no locally preferred plan. The sponsor fully supports the NER plan. The NER 

plan will best meet the sponsor’s goals of restoring oyster habitat in Pamlico Sound in 

conjunction with dredging operations at Old House Channel.

5.8.4 Designation of the Tentatively-Selected Plan

Alternative 16 is designated as the tentatively-selected plan due to the fact that it is both 

the NER plan as well as the locally preferred plan. Within the cost constraints of the 

Section 204 Authority, this plan will provide the greatest ecosystem restoration benefits 

in the most cost effective manner and is also the plan most desirable to the local 

sponsor while having minimal adverse environmental impacts. This plan will advance 

the goals of North Carolina’s oyster restoration efforts, including the NCORSC’s stated 

goal of 500 acres of new oyster reef constructed and designated as sanctuary by 2018. 

Restoration of oysters in North Carolina is also a national goal of the US EPA’s 

Albemarle-Pamlico Sound National Estuary Program. Lastly, it will alleviate the volume 

of dredged material placed on existing disposal islands during the associated dredging 

cycle, an objective supported by the NCWRC.

6.0 TENTATIVELY-SELECTED PLAN

6.1 Plan Description

The Tentatively-Selected Plan (TSP), having best met the alternative screening 

conditions in comparison to all other alternatives, is designated as the Recommended 

Plan. Under the TSP, three submerged oyster reefs would be constructed within close 

proximity of each other, approximately 1.7 miles from Old House Channel (Range 2). 

Stone sills made of NCDOT Class 2 armor stone (9”-23”) would be constructed to 

create three 5.07 acre containment areas for dredged material. The three 5.07 acre 

containment areas would contain a total of approximately 135,000 cubic yards of 

dredged material. The three separate containment areas would be constructed in close 

proximity of each other with spacing of approximately 100 yards. The core portion of 

the containment structures would be constructed of NCDOT Class B Stone (5”-12”).

Reefs would be constructed during a regularly scheduled maintenance dredging cycle 

for the navigation channels. Dredged material from maintenance dredging of the 

federal navigation channel would be pumped into the containment areas and would, 

most likely, utilize a hydraulic pipeline dredge. However, other dredges could be used. 

The dredged material would be covered with NCDOT Class A stone and oyster shell to 

provide habitat for establishment of oysters. A typical cross section is shown in Figure 

5.03. Approximately 18 acres of new oyster reef habitat would be created, as well as 

enhanced service area associated with the reefs. The construction of the preferred 

oyster reef alternative would be a one-time event under the Section 204 Authority. 
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However, this project could serve as a pilot for future oyster restoration efforts in 

conjunction with dredging operations.

6.2 Real Estate Requirements

The tentatively selected plan for the project consists of three 5.07 acre submerged 

oyster reefs within close proximity of one another (100 yards between one reef edge 

and another). Submerged stone containment rings will be constructed, and then filled 

with dredged material from maintenance dredging of Old House Channel. The sandbased reefs will then be topped with cultch for oyster reefs. The location of the reef 

configuration will be where good oyster growing conditions are found near the 

navigation channel and where submerged aquatic vegetation (SAV) or other significant 

resources do not immediately exist. The project study area is shown in Figures 2.01 

and 2.02. All reef development and construction will be accomplished below mean high 

water (MHW). These areas are considered lands of the State and a permit will be 

required from the State of North Carolina Department of Administration State Property 

Office for construction of the project in state waters.

As this project will make beneficial use of dredged material, no borrow site is required. 

The only real estate requirement identified is a staging area of approximately 0.5 of an 

acre that will be needed for an estimated period of 6-12 months. Two parcels as shown 

in Figures 6.0.1 and 6.0.2 are owned by the State of North Carolina and could be made 

available for staging areas. Only one parcel would be needed. Acquisition of a 

Temporary Work Area Easement for the staging area could be accomplished within 6

months.

Figure 6.01. Potential Staging Area Figure 6.02. Potential Staging Area 

 Dare County Hyde County
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The Temporary Work Area Easement. A temporary easement and right-of-way in, on, 

over and across (the land described in Schedule A) (Tracts Nos. _____), for a period 

not to exceed 12 months, beginning with date possession of the land is granted to the 

Sponsor for use by the Sponsor, its representatives, agents, and contractors as a work 

area, including the right to move, store and remove equipment and supplies, and erect 

and remove temporary structures on the land and to perform any other work necessary 

and incident to the construction of the Manteo, Old House Channel, NC Section 204 

Beneficial Use of Dredged Material for Oyster Reef Restoration Project, together with 

the right to trim, cut, fell and remove there from all trees, underbrush, obstructions, and 

any other vegetation, structures, or obstacles within the limits of the right-of-way; 

reserving, however, to the landowners, their heirs and assigns, all such rights and 

privileges as may be used without interfering with or abridging the rights and easement 

hereby acquired; subject, however, to existing easements for public roads and 

highways, public utilities, railroads and pipelines.

The proposed project would offer environmental improvements by creating new oyster 

reefs. No adverse environmental impacts are expected. No hazardous, toxic and 

radioactive wastes have been identified in the project area. There are no utility/facility 

relocations required for implementation of the project, and there are no relocations of 

individuals under PL 91-646. The project is not for commerce related purposes and has 

no nexus to navigation; therefore Navigation Servitude does not apply. There is no 

known public opposition to the project. 

The State of North Carolina is the non-Federal sponsor for the project (NFS). The NFS 

has the responsibility to acquire all real estate interests required for the Project. The 

NFS shall accomplish all alterations and relocations of facilities, structures and 

improvements determined by the government to be necessary for construction of the 

Project. The sponsor will have operation and maintenance responsibility for the project 

after construction is completed.

Title to any acquired real estate will be retained by the Project Sponsor and will not be 

conveyed to the United States Government. Prior to advertisement of any construction 

contract, the NFS shall furnish to the government an Authorization for Entry for 

Construction to all lands, easements and rights-of-way, as necessary. The NFS will also 

furnish to the government evidence supporting their legal authority to grant rights-of-way 

to such lands. The NFS shall comply with applicable provisions of the Uniform 

Relocation Assistance and Real Property Acquisition Policies Act of 1970, Public Law 

91-646, approved 2 January 1971, and amended by Title IV of the Surface 

Transportation Uniform Relocation Assistance Act of 1987, Public Law 100-17, effective 

2 April 1989, in acquiring real estate interests for the Project, and inform all affected 

persons of applicable benefits, policies, and procedures in connection with said Act(s). 

The non-Federal sponsor is entitled to receive credit against its share of project costs 

for the value of lands it provides and the value of the relocations that are required for 

the project. Generally, for the purpose of determining the amount of credit to be 

afforded, the value of the lands, easements and rights-of-way (LER) is the fair market 

value of the real property interest, plus certain incidental costs of acquiring those 
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interests, that the non-federal sponsor provided for the project as required by the 

Government. The NFS will not receive credit for lands used that were previously 

provided as an item of cooperation.

The NFS should not acquire lands required for the project prior to execution of the 

Project Partnership Agreement (PPA). Should the NFS proceed with acquisition of 

lands prior to execution of the PPA, it is at the risk of not receiving credit or 

reimbursement for any costs incurred in the connection with the acquisition process 

should the PPA not be signed. There is also risk in acquiring lands either not needed 

for the project or not acquired in compliance with requirements for crediting purposes in 

accordance with 49 CFR Part 24, dated March 2, 1989. A Realty Specialist will meet 

with the NFS prior to construction to discuss the real estate acquisition process and to 

provide guidance.

The estimated real estate costs include the land cost for acquisition of land and federal 

and non-federal administrative costs. Land cost is based on an opinion of value dated 

April 5, 2011 and on a market rental rate of 10% for one year. Administrative costs are 

those costs incurred for verifying ownership of lands, certification of those lands 

required for project purposes, legal opinions, analysis or other requirements that may be 

necessary during Planning, Engineering and Design (PED). A 25% contingency is 

applied to the estimated total for these items. Table 6.01 is a summary of the real 

estate cost for the project. 

 

Manteo Section 204 Real Estate Cost Estimate

Federal Non-Federal Total 

01B LANDS AND DAMAGES

01B40 Acq/Review of PS $ 5,000 $ $ $ 5,000 

01B20 Acquisition by PS $ $ 20,000 $ 20,000 

01BX Contingencies (25%) $ 1,250 $ 5,000 $ 6,250 

Subtotal $ 6,250 $ 25,000 $ 31,250 

01G Temporary Permits/Lic/ROEs

01G20 By PS $ $ 5,000 $ 5,000 

01GX Contingencies (25%) $ $ 1,250 $ 1,250 

Subtotal $ $ 6,250 $ 6,250 

01R REAL ESTATE LAND PAYMENTS

01R1B Land Payments by PS $ $ 5,500 $ 5,500 

01RX Contingencies (25%) $ 1,375 $ 1,375

Subtotal $ $ 6,875 $ 6,875 

TOTALS $ 6,250 $ 38,125 $ 44,375 

ROUNDED TO $ 44,500 

Table 6.01. Real Estate Cost Estimate
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6.3 Operation, Maintenance and Replacement Considerations

In accordance with Section 2039 of WRDA 2007, the recommended project includes a 

plan for monitoring the success of the ecosystem restoration. Monitoring will continue 

until success criteria have been met. For this project, a 5-year habitat 

establishment/persistence period is expected, therefore monitoring should be concluded 

in 5 years. However, if success criteria are not met, monitoring would continue as a 

project cost until year 10, and as sponsor cost thereafter. Both structural and biological 

persistence will be evaluated by hydrographic survey and biological sampling described 

below. Under the Section 204 authority, it is the responsibility of the local sponsor to 

maintain the project after construction. It is anticipated that little to no O&M activity will 

be required to maintain the functionality of the reef after construction. However, marker 

buoys would require replacement every two years. If 3-legged piles are used only one 

replacement would be expected during the project life. Cost to mark the corners of the 

sanctuary site with a three-legged piling system according to U.S. Coast Guard 

regulations and state permit is estimated to be $1,500 per pilling, times 12 pilings = 

$18,000. Assuming these are replaced at year 25, maintenance costs would be 

$18,000 over the life of the project.

The potential for an extended monitoring period have been addressed and adaptive 

management plans are described below; however due, to optimum site location as 

demonstrated by modeling and a successful nearby reference, the risk that extended 

monitoring or adaptive management would be needed is low. 

6..4 Monitoring and Adaptive Management Plan

In accordance with Section 2039 of WRDA 2007, the recommended project includes a 

plan for monitoring the success of the ecosystem restoration. Monitoring will continue 

until success criteria have been met. For this project, a 5-year habitat 

establishment/persistence period is expected, therefore monitoring should be concluded 

in 5 years. However, if success criteria are not met, monitoring would continue as a 

project cost until year 10, and as sponsor cost thereafter. Both structural and biological 

persistence will be evaluated by hydrographic survey and biological sampling described 

below. Under the Section 204 authority, it is the responsibility of the local sponsor to 

maintain the project after construction. It is anticipated that little to no O&M activity will 

be required to maintain the functionality of the plan after construction. l

The implementation guidance for Section 2039, in the form of a CECW-PB Memo dated 

31 August 2009, also requires that an adaptive management plan be developed for all 

ecosystem restoration projects. Several questions were considered to determine if 

adaptive management should be applied to the Manteo 204 project:

1) Are the ecosystems to be restored sufficiently understood in terms of hydrology 

and ecology, and can project outcomes be accurately predicted given recognized 
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natural and anthropogenic stressors? Yes, as demonstrated by a nearby successful 

reference at Crab Hole sanctuary. 

2) Can the most effective project design and operation to achieve project goals and 

objectives be readily identified? Yes. High relief structures would be consistent with 

NCDMF current practice.

3) Are the measures of this restoration project’s performance well understood and 

agreed upon by all parties? Yes. Performance measures will be consistent with 

established NCDMF Sanctuary Program monitoring measures.

4) Can project management actions be adjusted in relation to monitoring results? 

Yes. If unforeseen low recruitment were to occur proven methods are available to 

augment recruitment by stocking spat on shell. 

A “YES” answer to all 4 questions identified the project as a candidate which would not 

benefit from adaptive management . Therefore, the adaptive management plan is that 

no adaptive management would be required. 

Structural Persistence. A Hydrographic survey of the reef site identifying significant 

project features will be made upon completion (year 1) as a construction cost. This 

survey will document base conditions and construction compliance. A comparison 

monitoring survey will be made at the end of the monitoring period (Year 5) to determine 

structural persistence of project components. The aerial extent of the reef will be 

mapped and quantified. Visual documentation of site conditions by underwater camera 

sled will be conducted concurrent with the survey operation if water conditions permit.

Success Criteria. The Manteo 204 Reef Sanctuaries will be considered successful if at

the end of 5 years the site is documented to be in a generally stable condition. 

Adaptive Management. No Adaptive Management required.

Biological Persistence. Biological sampling would be conducted annually for 5 years

following construction. Monitoring would be extended to 10 years, if needed. 

Monitoring would include collection of reef stones and/or Quadrate Samples by Divers

to assess colonization by oysters and other fowling organisms. Three (3) randomly 

selected target areas would be evaluated by collection and analysis of 3 samples each, 

on an annual basis in years 1- 5. Methods will be consistent with NCDMF sanctuary 

sampling methods, as outlines below, to the degree practical. The information obtained 

will be compared to the previous year’s sampling results from the restoration site and 

annual state sanctuary Indexes as available. Faunal utilization of the site will be 

assessed by qualitative methods. An annual monitoring report will be prepared and 

coordinated with interested parties.

The following information will be collected for each sample per the NCDMF sanctuary 

sampling methods:

• Length x Width x Height of rock (mm)

• Number of live and dead oysters
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o3 size classes spat, sublegal and legal size oysters

• Height of each alive and dead (box) oyster. (Size distribution)

• Organisms found attached to rock and extent (fouling)

oBarnacles, mussels, tunicates, bryozoans, sponges, limpets, etc.

o Recorded as percent coverage using 7 graded scale which recognizes 

only seven possible coverage percentages; 1, 5, 10, 25, 50, 75, and 

100percent

• Presence and number of predators

oOyster drills, crabs, etc.

Success Criteria. Manteo 204 Sanctuary will be considered successful if at Year 5, the 

oyster density is at least 25 oysters/m2. (Combined all size classes) for 3 of the 5 years 

sampled. 

 

Adaptive Management. No Adaptive Management Plan. Additional cultch could be 

added to areas that are not supporting oyster habitat. 

 

MONITORING COST

Events Cost per Event No. of Events Total Cost

Survey Contract $30,000 1 $30,000

Biological Contract 15,944 5 79,720

Corps Support 10,000 6 60,000

Corp Dive inspector 5,000 5 25,000

Total 194,720

Total Cost Estimate $200,000*

* monitoring costs included as part of Total Project Costs and are cost shared 

on a 65% Federal/ 35% Non-Federal basis.
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6.5 Detailed Cost Estimate for Tentatively-Selected Plan

Total Project Cost (Fully Funded) including contingency is $7,217,000. For more detail and 

Cost MCX Certification, see Appendix D – Cost Engineering.

Table 6.02 Total Project Costs

TENTATIVELY-SELECTED PLAN, ALTERNATIVE 16

“THREE 5.07 ACRE SITES

WITH 4-FOOT STONE SILL CONTAINMENT STRUCTURE”

MANTEO, OLD HOUSE CHANNEL, NC 

SECTION 204 BENEFICIAL USE OF DREDGED MATERIAL 

FOR OYSTER REEF RESTORATION PROJECT

TOTAL PROJECT COSTS (Includes 19% Contingency)

Estimate Date: 2 August 2012

Prices

TOTAL PROJECT COSTS (FULLY FUNDED) $7,217,000

Non-Federal Share

Real Estate $38,125

Cash Contribution (35% of total implementation costs less RE) $2,328,875

TOTAL $2,367,000

Federal Share

Total Cost less Non-Federal Share $4,396,000

Feasibility Phase Cost, 100% Federally funded $453,000

TOTAL* $4,850,000

* The TOTAL maximum Federal expenditures on any one project under this 

authority is a maximum of $5,000,000.. Any costs over the $5,000,000 Federal 

limit will be 100% non-Federal and reflected as such in the PPA.

6.6 Cost Sharing

Under the Section 204 authority, the non-Federal sponsor is responsible for 35% of the 

Total Project Costs minus the feasibility phase costs.
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7.0 SUMMARY OF ENVIRONMENTAL IMPACTS

This section compares the impacts of the proposed Preferred Alternative (three 5.07 

acre sites with 4-foot stone sill containment) and the No-Action alternative. Fifteen 

alternatives that were eliminated from further consideration are outlined in section 5.3.3.

7.1 General Environmental Conditions

Neither the Preferred Alternative nor the No Action Alternative is expected to impact any 

environmental conditions within the study area or greater Pamlico Sound. Impact 

analyses of the environmental conditions are outlined below and summarized in table 

7.01.

7.1.1 Climate

Climate in the Pamlico Sound depends significantly on the Gulf Stream and the 

Labrador currents. As the Preferred or the No Action Alternatives would not have any 

impacts on these currents, neither the Preferred nor the No Action alternative would 

have an impact on the climate.

7.1.2 Tides, Currents, and Sea Level Rise

It is not expected that either the Preferred or No Action Alternative would significantly 

impact tides, currents, or sea level rise in the Pamlico Sound. Slight alteration of 

currents around the Preferred Alternative would result in minor localized changes in 

currents but should not have any impact on currents in the greater Pamlico Sound, nor 

would any potential localized changes be significant enough to alter the local conditions. 

Potential increase in sea level rise (between 0.87 and 2.2 feet over 50 years) would not 

impact the function of the alternatives discussed in the report. The elevation design of 

the preferred alternative is set to provide a minimum depth for safe vessel navigation 

and any rise in water level just provides additional buffer between the vessel and the 

reef/bottom. 

7.1.3 Water Quality 

The placement of armor stone and dredged material for this project, from the Federally 

authorized Navigation channel, would result in minor temporary turbidity during the 

construction but overall impacts to water quality would be minimal and of short duration. 

The Preferred Alternative would not contribute to point or non-point sources of 

pollutants and would not have any long-term negative impacts to water quality in the 

Pamlico Sound. Establishment of oysters on these constructed reefs would have 

positive benefits to water quality. A 401 Water Quality Certification would be required 

prior to construction.

Pursuant to Section 404 of the Clean Water Act, the impacts associated with the 

discharge of fill material into waters of the United States are discussed in the Section 

404(b)(1) (P.L. 95-217) evaluation in appendix XX. 
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The No Action Alternative would have no adverse impacts on water quality.

7.1.4 Current Land Use in Project Area

Neither the Preferred Alternative nor the No Action Alternative would impact land use,

as the project is located entirely within the waters of Pamlico Sound, away from all 

major upland areas. 

7.2 BIOTIC COMMUNITIES

The Preferred Alternative is not expected to have any long term negative impacts on 

biotic communities within the project area or the Pamlico Sound. The vast majority of

impacts to biotic communities would be in the placement of the rock sill with minor 

impacts as the area is recolonized by new species. Placement of the rock substrate 

would result in a permanent change in habitat substrate. Positive impacts associated 

with construction of the structures and stone sill substrate in an otherwise sandy flat 

community would provide benefits to species that would utilize the hard surfaces and 

higher surface elevation.

The No Action alternative would not have any impacts to biotic communities or facilitate 

the growth of certain communities that would utilize the structure and vertical elevation 

that would be provided by the Preferred Alternative. These impacts to biotic 

communities are outlined below.

7.2.1 Aquatic Habitats

7.2.1.1 Submerged Aquatic Vegetation 

The Preferred Alternative would not be located on or in the vicinity of any SAV beds as 

the nearest SAV bed is one-mile west of the proposed project site and would be far 

enough away from identified beds in the surveyed project area that potential negative 

impacts (turbidity) would be significantly reduced or eliminated (Figure 5.01). 

Construction would utilize methods to keep turbidity contained in the construction zone,

further reducing or eliminating any impacts that would be associated with sedimentation 

on the SAV habitat.

The No Action Alternative would have no impacts on SAV. 

7.2.1.2 Shell Bottoms. 

The Preferred Alternative would be sited to keep the proposed oyster reef location away 

from the known low relief shell bottom habitat identified in the survey area

approximately 0.5 miles north of the proposed site and oyster sanctuaries in the 

relatively near vicinity (Figure 5.01). By avoiding known shell bottoms and locating the 

proposed project area far enough away to avoid sedimentation from the construction of

the stone sill, and associated placement of dredged material, the Preferred Alternative 
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would not impact shell bottom. Positive impacts of providing habitat suitable for 

establishment of oysters and utilization by other species would provide positive benefits 

to an area that is dominated by soft bottom habitat.

The No Action Alternative would not provide additional oyster habitat and would not 

impact any shell bottom within the study area.

7.2.1.3 Soft Bottom 

Soft bottom makes up the majority of the substrate that will be altered under the 

Preferred Alternative. Construction would require the addition of rock sills which add 

hardened substrate to an otherwise sandy soft habitat with the total project area 

converting 5.07 acres of the sandy bottom to a higher relief hardbottom. However, these 

impacts and impacts associated with placing material would be expected to be minimal 

and, overall, provide more habitat diversity to the aquatic habitat. Dredged materials 

placed in the project area are expected to be of similar type and quality to that of the 

project area sediments. Invertebrates that utilize soft substrates would be expected to 

quickly re-colonize the sediments in the area.

The No Action Alternative would not impact the soft bottoms or the associated 

communities in the project area.

7.2.2 Bird Islands

Construction of the Preferred Alternative should not adversely impact the nearby bird 

islands. As many of the effluent islands have exceeded capacity for good bird habitat

by leaving them susceptible to predatory hazards, reducing the amount of material 

placed on these islands will promote a healthier and safer habitat for the birds that 

utilize the islands. Reduction in future material placement would therefore provide an 

overall positive impact to coastal bird communities.

The No Action Alternative would not directly impact bird islands or coastal birds. 

Secondary negative effects may occur by not providing an alternative disposal location 

for material that would otherwise go on islands that are already at or over capacity and 

subject to increases in predation.

7.2.3 Wetlands

While the Pamlico Sound contains estuarine wetlands, the proposed project area is not 

located in the vicinity of any wetlands. Therefore, there would be no impacts to wetlands 

from construction of the Preferred Alternative nor would there be impacts associated 

with the No Action Alternative.

As stated in section 7.1.3, Pursuant to Section 404 of the Clean Water Act, the impacts 

associated with the discharge of fill material into waters of the United States are 

discussed in the Section 404(b)(1) (P.L. 95-217) evaluation in appendix XX. While the 
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U.S. Army Corps of Engineers does not issue permits to its own agency, the agency 

complies with 404 regulations and nationwide permit conditions.

7.3 Threatened and Endangered Species

Neither the Preferred Alternative nor the No Action Alternative would be expected to 

have any adverse impacts to Threatened or Endangered Species that may be 

encountered in the project area. Potential species and associated assessment of 

impacts are outlined below.

Manatee. Pamlico Sound has not historically had manatee populations of any 

significant size, and manatees are not expected to be encountered in the project area. 

However, transport of materials as well as activities at the construction site would follow 

all manatee protocols regarding vessel traffic, further reducing any potential impacts 

associated with transport or construction. Therefore, the Preferred Alternative may 

affect but is not likely to adversely affect the species.

The No Action Alternative would not adversely impact the manatee.

Shortnose Sturgeon. The Preferred Alternative would not be located in habitat or 

breeding areas regularly utilized by shortnose sturgeon. Any sturgeon in the immediate 

project vicinity would be expected to safely transition out of the area with no impacts to 

individuals or the population. The project is in the vicinity of Oregon Inlet which is used 

by shortnose sturgeon as access to the estuary from the ocean. Structures related to 

the preferred alternative would not hinder access. Therefore, the Preferred Alternative 

may affect but is not likely to adversely affect shortnose sturgeon.

The No Action Alternative would not be expected to adversely affect shortnose 

sturgeon.

Atlantic sturgeon. The Preferred Alternative would not be located in habitat or 

breeding areas regularly utilized by Atlantic sturgeon. Any sturgeon in the immediate 

project vicinity would be expected to safely transition out of the area with no impacts to 

individuals or the population. The project is in the vicinity of Oregon Inlet which is used 

by shortnose sturgeon as access to the estuary from the ocean. Structures related to 

the preferred alternative would not hinder access. Therefore, the Preferred Alternative 

may affect but is not likely to adversely affect Atlantic sturgeon.

The No Action Alternative would not be expected to adversely affect Atlantic sturgeon.

Sea turtles. While sea turtles may potentially appear in the area, it is not anticipated 

that these species would be adversely affected by the Preferred Alternative. Planning 

for construction of the Preferred Alternative would include scheduling construction at 

times of the year when chances of encounters with sea turtles would be reduced to 

minimize potential impacts. While there are currently no restrictions on dredging, any 

schedule constraints would be based on the Operations and Maintenance contracts

and, if any, windows for disposal established during consistency coordination. During 
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construction, it is anticipated that a hydraulic pipeline dredge would be used although 

the dredge project has authority to use other dredges. The Preferred Alternative would 

not impact beaches adjacent to the proposed project area, where sea turtles have been 

known to nest. 

The No Action Alternative would not result in adverse affects to sea turtles.

Birds. As the Preferred Alternative would not be located within the immediate vicinity of 

islands or beaches where Piping Plovers or Roseate Terns nest, and would not impact 

fisheries resources that shorebirds rely on, no negative effects are anticipated beyond 

the potential temporary minor impacts associated with disturbance by equipment during 

the construction phase. Therefore, this project may affect but is not likely to adversely 

affect threatened or endangered bird species.

The No Action Alternative would not have any adverse effects to Threatened or 

Endangered bird species.

7.4 Benthic Resources

The Preferred Alternative is not expected to negatively impact benthic resources 

beyond minor temporary impacts during placement of dredged material during 

construction. Minor impacts would be associated with burial of species located on the 

sandy bottom habitat. However, due to the nature of the system being highly dynamic, 

these impacts are not expected to be long term with species recovering in the 

immediate area rapidly following the disturbance. Facilitation of oyster growth by 

providing suitable habitat should promote not only oysters but other benthic organisms 

that would utilize the constructed reef. 

The No Action Alternative is not expected to negatively impact benthic resources;

however, by not providing additional habitat that can be utilized by benthic species, the 

No Action Alternative would not promote growth of the benthic community. Therefore, 

with the No Action Alternative, conditions would be expected to remain generally status 

quo with minimal to no impacts to resources.

7.5 Essential Fish Habitat (EFH) and Fisheries

Potential impacts to EFH and HAPC that are in the project area of the Preferred Plan 

are discussed and summarized in the following paragraphs.

Aquatic Beds. Aquatic beds (defined as assemblages of submerged rooted vascular 

vegetation found in tidal freshwater areas) are not found in the immediate project area 

due to the salinity of waters; therefore, no impacts from the Preferred or No Action 

Alternatives would occur. 

Estuarine Water Column. The Preferred Alternative is expected to create localized, 

short-lived turbidity elevations that should dissipate within the estuarine water column in 
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a short time period. In addition to the actions of winds, waves, and currents, the 

duration of these turbidities would be dependent upon the grain-size of material being 

placed: the finer the grain-size, the slower the return to pre-construction conditions. The 

results of grain-size analyses from Old House Channel and past dredging events show 

that sand is the predominant sediment and, as such it is expected that turbidities would 

be slightly elevated above those routinely present in the area but should return to 

normal levels quickly once construction is complete, with minimal and short-term 

impacts.

The No Action Alternative would not result in any impacts to the estuarine water column. 

Oyster Reefs and Shell Banks. These habitat types are present in the area of 

Pamlico Sound and occur within the project study area (see figure 4.04). Placement of 

dredged material under the Preferred Alternative is not expected to affect these 

habitats, as the Preferred Alternative would be located in areas away from oyster reefs 

and shell banks. Turbidities as a result of construction would be far enough removed 

from any potential reefs or shell banks as to not cause impacts to those resources. 

Construction of additional oyster reefs should have positive impacts to the surrounding 

populations by providing additional habitat that is currently unavailable to oysters due to 

the depth and lack of suitable substrate. The preferred alternative is not expected to 

cause any negative impacts to oyster reefs and should result in overall positive impacts 

to the oyster community in Pamlico Sound.

The no action alternative should not provide any direct negative impacts but will not 

provide additional oyster and shell habitat thereby not supporting North Carolina’s 

oyster restoration goals. 

SAV and Seagrasses. Shallow bottom within the project study area (Figure 4.04) 

contains habitat suitable for SAV and SAV communities. The proposed oyster reef 

construction could potentially impact SAV habitat. However, precautions would be 

taken to avoid areas where SAV are known to exist and the Preferred Alternative 

location will be far enough away from SAV to eliminate potential impacts from burial or 

turbidity during construction with the nearest site being located currently one-mile north

of the proposed site. Once constructed, the Preferred Alternative should have no 

negative impacts and may possibly, as a secondary benefit, facilitate SAV growth in

nearby waters if water clarity improves due to filtering by oysters.

The No Action Alternative would have no impact on any known SAV or its habitat.

State–designated Areas Important for Managed Species. Primary Nursery Areas 

(PNAs) are designated by the NC Marine Fisheries Commission and are defined as tidal 

saltwaters that provide essential habitat for the early development of commercially 

important fish and shellfish. There are PNAs in Pamlico Sound, but this project is at 

least five-miles away from these locations so that neither the construction of the oyster 

reefs nor the disposal would have adverse impacts. 
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The No Action Alternative would have no impacts on any State-designated areas.

Impact Summary for Essential Fish Habitat. Adverse impacts to EFH, HAPC, or 

EFH species from construction of the Preferred Alternative, if any, has been determined 

to be minimal and short-lived on an individual and cumulative effects basis. As a result 

of these minimal impacts and based on agency coordination at the January 10, 2012 

meeting in Manteo, NC, mitigation to offset impacts is not expected to be required. This 

assessment will be coordinated with the NMFS Southeast Region.

7.6 Sediments

Due to the highly dynamic environment of Oregon Inlet and Pamlico Sound, it is not 

expected that the relocation of sediments from the Federally Authorized channel to the 

Preferred Alternative location would have any significant long term impacts to sediments 

in the project area. Sediment composition is consistent between the channel and 

preferred alternative location, so grain size and quality is not expected to change during 

construction of the Preferred Alternative. Project impacts during construction may 

include slightly elevated turbidity conditions at the Preferred Alternative site however; 

this is expected to be a short-term impact with sediments settling rapidly in the system.

The No Action alternative will not impact sediments in Pamlico Sound.

7.7 Coastal Processes

The proposed project would be located beneath the water surface at all times, leaving 

the site relatively protected from the effects of winds, waves, and tidal fluxes. Due to the 

submerged location it is not expected that the project would alter the coastal processes 

of the project area; therefore, no impacts to coastal processes are expected.

The No Action alternative would not impact coastal processes.

7.8 Air Quality

The Preferred Alternative would result in minimal temporary impacts to air quality during 

the construction phase of the project. Air emissions would be slightly elevated during 

construction from the operation of heavy machinery and vessel equipment. These 

impacts are expected to be minimal and short term. No open burning would occur 

during any phase of this project.

The No Action Alternative will not result in increases in air emissions and will have no 

impact on air quality.

7.9 Socio-Economics and Recreation

The Preferred Alternative would provide additional fishing and shellfish habitat boosting 

both local recreational fisheries and the tourism industry in the areas surrounding the 
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project site. This would have a positive effect on the local community. Design of the 

Preferred Alternative avoids any impacts to navigation and, by providing an additional 

disposal location for material dredged from the channel to maintain navigation depth, 

aids in maintaining the federally authorized navigation channels which support the local 

economy.

The No Action Alternative is not expected to have any impacts on the local economy or 

recreation.

7.10 Cultural Resources

After review of the ERDC survey report conducted by the USACE Field Research 

Facility in Duck, NC, the North Carolina State Historic Preservation Office concluded 

that it was unlikely that the Manteo 204 project would affect any significant submerged 

resources (Appendix H).

7.11 Hazardous, Toxic, and Radioactive Wastes

The Preferred Alternative will not be located in any area where HTRW have been 

identified nor will the alternative result in the creation of HTRW. No impacts related to 

HTRW are expected to occur with either the Preferred or No Action Alternatives.

7.12 Floodplains

As the project is not located within a floodplain and will not alter any surrounding 

floodplains, neither the Preferred Alternative nor the No Action Alternative will cause 

any impacts to floodplains.

7.13 Cumulative Impacts

Cumulative impacts associated with the preferred alternative were considered. There 

are ten existing state estuarine reefs in the greater Pamlico Sound; of these, two are 

within 2.5 miles of the proposed site. These reefs were constructed at or over a decade 

ago by NCDMF and cover a total of 39 acres. Another reef within the vicinity is currently 

in the planning stage with no additional new reefs expected in the foreseeable future 

within Pamlico Sound, other than the proposed project. The success of the sanctuaries 

in the Albemarle-Pamlico Estuary System along with the success of the naturally 

sustaining subtidal oyster reef ecosystem restoration project at Festival Park suggest 

that the preferred plan will facilitate further re-establishment of oysters in the Pamlico 

Sound and aid in creating a more stable naturally sustainable oyster population.

Additional projects in the area include the Manteo (shallowbag) Bay project which was 

authorized in 1940 and is considered a navigation maintenance project. This project

includes maintenance of several navigation channels and runs parallel to the Outer

Banks adjacent to the proposed project site. No other federal dredge work is proposed 

for this project area. Proposed project design using material from this maintenance 
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channel would provide an alternative location for placement of channel materials 

relieving the adjacent islands of the excess dredged material which will benefit both the 

birds that may utilize the islands while providing available substrate for oyster 

recruitment.

As a proposed beneficial use of dredged material project, net effects are expected to be 

beneficial. Any adverse effects would be minor and temporary, associated with 

construction disturbance. An insignificant reduction in soft bottom habitat would occur 

as soft bottoms are converted to oyster habitat. 

Table 7.01 Summary of Environmental Impacts

Resource

Alternatives

Proposed Action 

3-5.07 Acre sites with 4-foot stone 

sill containment

No Action

Climate No impacts No impacts 

Tides, Currents, and 

Sea Level Rise No impacts No impacts

Water Quality

Minor temporary turbidity during 

construction

Long term positive benefits from 

Oysters

No impacts

Land Use No impacts No impacts 

SAV Potential minor short-term turbidity No impacts

Shell Bottom

No impacts to existing hardbottom

Positive benefits from increased 

available habitat

No impacts to existing 

hardbottom

No additional habitat

Soft Bottom Loss of soft bottom habitat at 

constructed reef No impacts

Bird Islands Reduced predation and disposal 

placement on islands

Potential increase in 

predation and continued 

frequent disposal on islands 

Wetlands No impacts No impacts

Threatened and 

Endangered Species No impacts expected No impacts
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Resource

Alternatives

Proposed Action 

3-5.07 Acre sites with 4-foot stone 

sill containment

No Action

Benthic Resources Facilitation of habitat to promote 

benthic growth No impacts

EFH Minimal to no impacts

No impacts

No additional shell habitat

Sediments Short-term elevated turbidity No impacts

Coastal Processes No impacts No impacts

Air Quality Short term elevated emissions No impacts

Socio-economics Boost local recreational fisheries No impacts

Cultural Resources No impacts expected No impacts

HTRW No impacts No impacts

Floodplains No impacts No impacts

8.0 COMPLIANCE WITH ENVIRONMENTAL PROTECTION STATUTES 

AND EXECUTIVE ORDERS

The Recommended Plan, as built, must comply with applicable state and federal 

environmental protection statutes and executive orders, including NEPA. Applicable 

state and federal permitting, with the required public review, must be accomplished prior 

to construction of the project. A listing of the federal laws and policies and their 

compliance status is located in Table 8.01. 
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Table 8.01. Listing of Public Laws and Compliance Status (Note: Items identified as 

being in Full Compliance assumes their compliance status after the NEPA process is 

complete.) 

Title of public law U.S. Code

Compliance 

status

Abandoned Shipwreck Act of 1987 43 U.S.C. 2101 Full Compliance

American Indian Religious Freedom Act 42 U.S.C. 1996 Not Applicable

Agriculture and Food Act (Farmland Protection Policy Act) of 1981 7 U.S.C. 4201 et seq. Not Applicable

American Folklife Preservation Act of 1976, As Amended 20 U.S.C. 2101 Not Applicable

Anadromous Fish Conservation Act of 1965, As Amended 16 U.S.C. 757 a et 

seq.

Full Compliance

Antiquities Act of 1906, As Amended 16 U.S.C. 431 Full Compliance

Archeological and Historic Preservation Act of 1974, As Amended 16 U.S.C. 469 Full Compliance

Archeological Resources Protection Act of 1979, As Amended 16 U.S.C. 470 Full Compliance

Bald Eagle Act of 1972 16 U.S.C. 668 Full Compliance

Buy American Act 41 U.S.C. 102 Full Compliance

Civil Rights Act of 1964 (P.L. 88-352) 6 U.S.C. 601 Full Compliance

Clean Air Act of 1972, As Amended 42 U.S.C. 7401 et seq. Full Compliance

Clean Water Act of 1972, As Amended 33 U.S.C. 1251 et seq. Full Compliance

Coastal Barrier Resources Act of 1982 16 U.S.C. 3501-3510 Full Compliance

Coastal Zone Management Act of 1972, As Amended 16 U.S.C. 1451 et seq. Full Compliance

Comprehensive Environmental Response, Compensation and 

Liability Act of 1980 

42 U.S.C. 9601 Not Applicable

Conservation of Forest Lands Act of 1960 16 U.S.C. 580 mn Not Applicable

Contract Work Hours 40 U.S.C. 327 Full Compliance

Convict Labor 18 U.S.C. 4082 Full Compliance

Copeland Anti-Kickback 40 U.S.C. 276c Full Compliance

Davis Bacon Act 40 U.S.C. 276 Full Compliance

Deepwater Port Act of 1974, As Amended 33 U.S.C. 1501 Not Applicable

Emergency Flood Control Funds Act of 1955, As Amended 33 U.S.C. 701m Not Applicable

Emergency Wetlands Resources Act 16 U.S.C. 3901-3932 Full Compliance

Endangered Species Act of 1973 16 U.S.C. 1531 Full Compliance

Estuary Program Act of 1968 16 U.S.C. 1221 et seq. Full Compliance

Equal Opportunity 42 U.S.C. 2000d Full Compliance

Farmland Protection Policy Act 7 U.S.C. 4201 et seq. Not Applicable
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Federal Environmental Pesticide Act of 1972 7 U.S.C. 136 et seq. Full Compliance

Federal Water Project Recreation Act of 1965, As Amended 16 U.S.C. 4601 Full Compliance

Title of public law U.S. Code

Compliance 

status

Fish and Wildlife Coordination Act of 1958, As Amended 16 U.S.C. 661 Full Compliance

Flood Control Act of 1944, As Amended, Section 4 16 U.S.C. 460b Full Compliance

Food Security Act of 1985 (Swampbuster) 16 U.S.C. 3811 et seq. Not Applicable

Hazardous Substance Response Revenue Act of 1980, As 

Amended 

26 U.S.C. 4611 Not Applicable

9.0 SUMMARY COORDINATION, PUBLIC VIEWS, AND COMMENTS

9.1 Scoping Comments and Responses

A scoping letter describing the proposed project, dated May 27, 2009, was circulated to 

resource agencies and the public for review and comment. There were no comments 

received from the general public. All scoping comments from other agencies were 

considered during the development of this project. A summary of comments received 

from stakeholder organizations and resource agencies, along with USACE responses 

referenced to appropriate sections of this document, is presented in Appendix A.

9.2 Stakeholder Meetings

In addition to ongoing communication via phone and e-mail, an agency coordination 

meeting was held in Manteo, NC on January 10, 2012 with representatives from the 

following agencies and stakeholders: National Marine Fisheries, NC Division of Marine 

Fisheries, NC Division of Water Resources, NC Shellfish Sanitation, NC Ferry Division, 

NCDCM, and The Nature Conservancy.

10.0 PLAN IMPLEMENTATION

10.1 Non-Federal Responsibilities

The State of North Carolina, as stated in a letter dated July 15, 2008 (Appendix B), has 

expressed support of the project with the financial capability to execute a project 

partnership agreement, and has agreed to accept the role of non-Federal sponsor in 

event of approval of a final feasibility report. The State of North Carolina has statutory 

authority under the Federal Water Resources Development Law of 1969 (G.S. 143-

215.38 et. seq.) to make binding commitments to carry out the non-Federal 

responsibilities related to USACE projects, including making cash contributions to 
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projects. In order to implement the Selected Alternative, the State of North Carolina, as 

non-Federal sponsor, would be responsible for the following:

1. Legal provision, without cost to the U.S. Government, of all necessary land, 

easements, rights-of-way, and access routes necessary for project construction 

and subsequent operation and maintenance. Land provisions would include:

a. construction site to accommodate all oyster restoration habitat 

improvement features to be constructed, and 

b. Temporary staging area(s) of acceptable location and acreage for 

contractor’s use during construction period.

2. Cash contribution, provided during the period of implementation, toward cost of 

the project totaling 35% of project first cost, less value of the non-Federal 

sponsor’s real estate contribution. The amount of cash contribution is currently 

estimated to be $2,335,150. The State of North Carolina has stated their intent 

by letter dated July 15, 2008 (Appendix B), to accept the non-Federal sponsor’s 

responsibilities as defined in a Project Partnership Agreement, should a final

feasibility report be approved. 

3. Funding of 100% of the cost of Annual Operation and Maintenance (O&M)

required to keep the project in viable condition to satisfy its design function. This 

funding would not be provided for initial implementation of the project, but would 

become a yearly responsibility of the non-Federal sponsor upon completion of 

the construction phase. O&M costs are estimated to be $18,000 over the life of 

the project (see section 6.3 for details). 

4. Satisfy all provisions of the Project Partnership Agreement (PPA) regarding nonFederal sponsor responsibilities in implementing the project.

10.2 Federal Responsibilities

In order to implement the Selected Alternative, the USACE would provide the Federal 

share of project cost, to equal project first cost less the total non-Federal share, not 

including Annual Operation and Maintenance expenses. The Federal share of project 

cost is currently estimated to be $4,423, 028, not including feasibility phase costs. Total

Federal expenditures on any one project under Section 204 authority may not exceed a 

total of $5 million. The additional cost of Federal Feasibility Phase work, currently 

estimated at $493,000 would be 100% Federally-funded. The USACE would also 

provide the following:

1. Review and certification of Real Estate provisions.

2. Planning, Engineering, and Design (PED) of the project.

3. Contracting for project construction.

4. Supervision and Administration of project construction.
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10.3 Work-in-Kind

Work-in-Kind is defined as work contributed by the non-Federal sponsor toward 

implementation of a project, in lieu of payment of a portion of the sponsor’s cash 

contributions toward implementation of the project. In some cases, completed Work-inKind may be credited by the USACE to the non-Federal sponsor, resulting in a 

reduction of their cash contribution on behalf of the project. The NCDMF has expert 

knowledge of oyster management in the project area with facilities and capability to 

provide and or place cultch and conduct oyster monitoring. Coordination is underway 

with the sponsor to determine their interest in providing work in-kind. 

10.4 Project Partnership Agreement (PPA)

Upon approval of a final feasibility report for this Manteo, Old House Channel, NC 

Section 204 project, a project partnership agreement (PPA) would be created. A PPA is 

a legally binding agreement between the Federal government (in this case, the USACE) 

and a non-Federal sponsor (in this case, the State of North Carolina) for construction of 

a water resources project, in this case, the Manteo, Old House Channel, NC - Beneficial 

Use of Dredged Material for Oyster Reef Restoration Project. The PPA would describe 

the project and the responsibilities of the USACE and the State of North Carolina in the 

cost sharing and execution of project work.

10.5 Sponsor Views

The State of North Carolina, as non-Federal sponsor, has expressed support for this 

project by requesting the USACE, in 2008, to investigate opportunities for oyster 

restoration in the Pamlico system (See letter from the North Carolina Department of 

Natural Resources, Division of Water Resources, dated July 15, 2008, in Appendix B). 

The State also enacted new coastal stormwater rules at that time to protect and improve 

the water quality in the Pamlico system, which, along with its oyster populations, had 

experienced indicators signaling the potential of continuing decline. The State has also 

indicated a willingness and financial capability to execute a project partnership

agreement (PPA) should this detailed project report be approved. The State’s 

preference among the alternative plans (“Locally-Preferred Alternative”) is Alternative 16

(3 5-acre reef complex with stone containment). Since this alternative is also the 

Federally-Recommended Alternative, it is considered the Recommended Plan.

11.0 RECOMMENDATIONS

The Tentatively-Selected Plan, Alternative 16, has been determined to be the plan that 

would provide the greatest ecosystem restoration benefits in the most cost effective 

manner within the cost constraints of the Section 204 Authority, and is also the plan 

most desirable to the local sponsor while having minimal adverse environmental 

impacts. This plan has therefore been selected as the Recommended Plan for 

implementation, upon approval of a final feasibility report and execution of a PPA.
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12.0 DRAFT FINDING OF NO SIGNIFICANT IMPACT

The proposed action is not expected to significantly affect the quality of the human 

environment. If this determination is confirmed through coordination of this EA, an 

Environmental Impact Statement will not be required, and a Finding of No Significant 

Impact (FONSI) will be signed prior to the initiation of the proposed action. The signed 

FONSI will be made available to the public.

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Sturgeon (Acipenser oxyrinchus oxyrinchus). Report to National Marine Fisheries 

Service, Northeast Regional Office. February 23, 2007. 174 pp.

Angley, Wilson. 1985. An Historical Overview of Oregon Inlet. Report on file at the 

Research Branch, NC Division of Archives and History, Raleigh, NC.

Associate Filtered Press (AFP). 2011. Oysters disappearing worldwide: study (posted 

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db30.2d1&show_article=1

Cake, E.W. 1983. Habitat Suitability Index Models: Gulf of Mexico American Oyster. 

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Cressman, K.A., Posey, M.H., Mallin, M.A., Leonard, L.A., Alphin, T. 2003. Effects of 

oyster reefs on water quality in a tidal creek estuary. Journal of Shellfish 

Research 22:753-762.

Dahl, Thomas E. 1990. Wetlands losses in the United States 1780's to 1980's. U.S. 

Department of the Interior, Fish and Wildlife Service, Washington, D.C. Jamestown, 

ND: Northern Prairie Wildlife Research Center 

Online.http://www.npwrc.usgs.gov/resource/wetlands/wetloss/index.htm

Deaton, A.S., Chappell, W.S., Hart, K., O’Neal, J., Boutin, B. 2010. North Carolina 

Coastal Habitat Protection Plan. North Carolina Department of Environment and 

Natural Resources. Division of Marine Fisheries, NC. 639 pp.
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dos Santos, L.N., Brotto, D.S., and Zalmon, I.R. 2010. Fish responses to increasing 

distance from artificial reefs on the Southeastern Brazilian Coast, Journal of 

Experimental Marine Biology and Ecology, Volume 386, Issues 1-2, 30 April 

2010, Pages 54-60, ISSN 0022-0981, DOI: 10.1016/j.jembe.2010.01.018.

Frankenberg, D. 1995. North Carolina Blue Ribbon Advisory Council on Oysters: Final 

Report on Studies and Recommendations.

Jones, C.G., Lawton, J.H., Shachak, M. 1994. Organisms as ecosystem engineers. 

Oikos 69: 373-386.

Kennedy, V.S., Newell, R.I., and Eble, A.F. 1996. Eastern Oyster: Crassostrea 

virginica. University of Maryland, Sea Grant Program, College Park, MD.

Mann, R. 2001. Oyster reefs as fish habitat: Opportunistic use of restored reefs by 

transient fishes. Journal of Shellfish Research 20:951-959.

Murawski, S. A. and A. L. Pacheco. 1977. Biological and fisheries data on Atlantic 

Sturgeon, Acipenser oxyrhynchus (Mitchill). National Marine Fisheries Service 

Technical Series Report 10: 1-69.

National Marine Fisheries Service. 1998. Recovery Plan for the Shortnose Sturgeon 

(Acipenser brevirostrum). Prepared by the Shortnose Sturgeon Recovery Team 

for the National Marine Fisheries Service, Silver Spring, Maryland. 104 pages.

NCCF (North Carolina Coastal Federation). 2008. DRAFT Oyster Restoration and 

Protection Plan for North Carolina: A Blueprint for Action. 2nd ed. (2008–2012). 

NCCF, Oyster Restoration and Protection Plan Steering Committee.

NC Department of Environment and Natural Resources – Division of Air Quality.

Website:

http://www.ncair.org/

NCDMF (North Carolina Division of Marine Fisheries). Website: 

http://www.ncfisheries.net/habitat/index.html

NCDMF. 2001. North Carolina oyster fishery management plan. North Carolina 

Division of Marine Fisheries, Department of Environment and Natural Resources.

NCDMF. 2008. North Carolina Oyster Fishery Management Plan. North Carolina 

Department of Environment and Natural Resources, North Carolina Division of 

Marine Fisheries. Website:

http://www.ncfisheries.net/rules.htm.
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NCDMF. 2010 Species Stock Status Report. Website: 

http://www.ncfisheries.net/stocks/oyster.htm

NCDMF CHPP (Coastal Habitat Protection Plan). Documents and Downloads 

webpage:

http://www.ncfisheries.net/habitat/chpp28.html)

NCDMF. North Carolina's Oyster Sanctuary Program. Retrieved July 25, 2009, from 

North Carolina Division of Marine Fisheries, Morehead City, North Carolina. 

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