19930222 Ver 1_COMPLETE FILE_19920101

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State of North Carolina
Department of Environment, Health, and Natural Resources
Division of Environmental Management
512 North Salisbury Street • Raleigh, North Carolina 27604
James G. Martin, Governor A. Preston Howard, Jr., P.E.
William W. Cobey, Jr., Secretary October 12, 1992 Acting Director
MEMORANDUM
To: Monica Swihart
Through: John Dornoq
From: Eric Galamb r
Subject: Water Quality Checklist for EA/EIS/Scoping Documents
Proposed Dredging of the Wilmington Harbor Ocean Bar Channel
New Hanover County
EHNR # 93-0222, DEM WQ # 7126
The Water Quality Section of the Division of Environmental Management requests that
the following topics be discussed in the EA/EIS/Scoping documents:
A. Wetland Impacts
i) Identify the federal manual used for identifying and delineating
jurisdictional wetlands.
ii) Have wetlands been avoided as much as possible?
iii) Have wetland impacts been minimized?
iv) Mitigation measures to compensate for habitat losses.
v) Wetland impacts by plant communities affected.
vi) Total wetland impacts.
vii) List the 401 General Certification numbers requested from DEM.
B. Will waste locations be in wetlands?
C. Discuss efforts to minimize impacts to water quality.
Written concurrence of 401 Water Quality Certification may be required for this project.
Please be aware that 401 Certification may be denied if wetland impacts have not
been avoided and minimized to the maximum extent practicable.
checklis.sco
REGIONAL OFFICES
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Pollution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

DEPARTMENT OF ENVIRONMENTMEALTHAND NATURAL RESOURCES
DIVISION OF PLANNING AND ASSESSMENT
PROjECT REVIEW FORM
j f2 (^
ETLE - COPING -° PROPOSED DREDGING OF THE WILMINGTON HARBOR OCEAN BAR
f:;I"IANNE TO CORRECT A CONSTRUCTION DEPTH DEFICIENCY
R O .. EC:'T.
NO - 93-0222
]UNT'r - NEW HAN(:1VE:.R
ATE: - 09/30/92
0PONSE DUE: DATE „' E. 3
Et . rt*-
iocT 8
DISTRIBUTION LIST
DIVISION OF MARINE FISHERIES
DIVISION OF COASTAL MANAGEMEN 'T
WILDLIFE
ENVIRONMENTAL HEALTH
FOREST RESOURCES
SOIL.. AND WATER
WILMINGTON REGIONAL OFFICE
AQ, WQ, GW, LQ
ENVIRONMENTAL MANAGEMENT kGW? c.
ENVIRONMENTAL MANAGEMENT (WQ) r
PARKS AND RECREATION
WATER PLANNING
OTHER WATER QUALITY
SECTION
:.
iNAGE R SIGN-OFF/REGION' : DATE:
-HOUSE REVIEWER/AGENCY: DATE:::
A RESULT OF THIS REVIEW, THE FOLLOWING IS SUBMITTED:
_._. NO OBJECTION TO PROJECT AN PROPOSED
__ NO COMMENT"
INSUFFICIENT INFORMATION
CONSISTENCY STATEMENT NEEDED NOT NEEDED
_ OTHER (SPECIFY AND ATTACH COMMENTS)
ENVIRONMENTAL DOCUMENT REQUIRED UNDER THE
PROVISIONS OF NEPA FIND SEPA
RETURN TO MELBA MC GEE, DIVISION OF PLANNING AND ASSESSMENI*
,

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO
Dear Sir or Madam:
Septemberr25, 1992
i;

We are conducting studies for the preparation of an Environmental
Assessment (EA) or Environmental Impact Statement (EIS) for dredging of
the Wilmington Harbor Ocean Bar Channel to correct a construction depth
deficiency. We are now requesting comments from agencies, interest groups,
and the public to identify significant resources, issues of concern, and
recommendations for studies considered necessary. Comments received as a
result of this scoping letter will be considered as we conduct our studies
and identify potential impacts on environmental quality. These items will
be addressed, as appropriate, in the EA or EIS.
The Wilmington Harbor Ocean Bar Channel (also called Baldhead Shoal
Channel) is located at the mouth of the Cape Fear River and extends seaward
into the Atlantic Ocean (figure 1). This channel has been federally main-
tained for over 100 years. Authorized channel dimensions include a 500-foot
width, a 40-foot depth at mean low water (m.l.w), and 2 feet of allowable
overdepth. Construction of the channel to these authorized dimensions
was completed in 1973, except that the authorized depth was not uniformly
achieved due to rock obstructions and survey inaccuracies. In 1990, it
was determined that the actual controlling depth is approximately 38 feet
due to the presence of several areas of rock in the channel. This depth
is inadequate to allow full utilization of the interior channels of the
Wilmington Harbor project, and larger vessels using the project must be
light loaded or wait for high tide to overcome this depth constraint
in the ocean bar channel. The North Carolina State Ports Authority has
requested that the authorized 40-foot depth be provided.
A plan is.proposed to achieve the authorized 40-foot project depth,
plus an additional 4 feet of required overdepth, to accumulate shoaled
sediments between maintenance dredging events, and an additional 2 feet
of allowable overdepth for dredging inconsistencies. Such depths have
previously been considered achievable only by drilling and blasting the
rock along the channel bottom. However, during the spring of 1992, we
were able to remove rock using a rock cutterhead on a hydraulic pipeline
dredge, so it is now considered feasible and practical to dredge to
this depth without blasting. Dredged material would be transported to a
disposal site by pipeline, hopper dredge, or dump scow. The plan would
also include extending the full channel depth seaward to approximately
station 350+00 (35,000 feet seaward of the intersection of Baldhead Shoal
Channel and Smith Island Channel). This point is about 11,000 feet beyond
the previously constructed and maintained channel, which ends at station
240+00. The channel would have side slopes of 1 vertical: 5 horizontal.

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The estimated amount of dredged material to be removed is approximately
4 million cubic yards. The seaward channel extension and the increased
side slopes would result in the disturbance of approximately 170 acres of
ocean bottom, in addition to the 310 acres of channel bottom and side
slopes which are currently affected by maintenance dredging approximately
every 12 months. Disposal of dredged material could be at the Wilmington
Ocean Dredged Material Disposal Site, but other alternatives will also be
considered. If suitable types and amounts of material could be obtained,
disposal alternatives could include (1) deposit of sand on the beach at
Bald Head Island and/or (2) construction of an offshore rock reef for fish
habitat. Plan modifications and disposal alternatives will be addressed,
as appropriate, during preparation of the EA or EIS.
Environmental resource concerns relative to channel deepening and
seaward extension include the potential direct 'impacts of dredging and the
placement of dredged material. Resources that will be addressed include
endangered and/or threatened species; marine and estuarine habitat; marine
and estuarine life; cultural resources, including important historic ship-
wrecks; and water quality. In addition, the indirect effect of channel
alteration on salinity changes within the Cape Fear River estuary and
coastal shoreline erosion at nearby ocean beaches will be addressed. The
beneficial use of dredged material for beach nourishment or fishery reef
construction will also be examined.
There is some concern that rock in the channel may prove to be too
hard for totally successful removal under the proposed plan. In this event,
limited drilling and blasting of any remaining rock could be required. As
advance preparation for such a situation and in order to assess and document
potential environmental effects, we would like to begin accumulating data,
comments, and suggestions concerning potential impacts of underwater
blasting and descriptions of measures for minimizing such impacts.
We request that you provide written comments on any of these matters
within 30 days from the date of this letter. If we have not received your
comments by then, we will assume that you have none. Comments should be
addressed to the District Engineer, (Attention: Mr. John Meshaw), U.S. Army
Corps of Engineers, Wilmington District, Post Office Box 1890, Wilmington,
North Carolina 28402-1890. If you have any questions, please contact
Mr. Meshaw, Environmental Resources Branch, at telephone [phone].
Sincerely,
Walter S. Tulloch
Colonel, Corps of Engineers
District Engineer
Enclosure
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United States Department of the Interior
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FISH AND WILDLIFE SERVICE
Raleigh Field Office
Post Office Box 33726
Raleigh, North Carolina 27636-3726
October 28, 1992
Mr. John Dorney
N.C. Division of Environmental Management
Post Office Box 29535
Raleigh, North Carolina 2762.6-0535
Dear Mr. Dorney,
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Attached is the Service's Planning Aid Report for the
Wilmington Harbor Ocean Bar Channel Deepening Project, New
Hanover County, North Carolina being conducted by the
Wilmington District U.S. Army Corps of Engineers. This
preliminary report identifies baseline fish and wildlife
resources in the general study area, discusses potential
impacts to these resources, outlines future information which
is needed for further analysis of this project, and offers
preliminary recommendations to the Corps to use in project
plans.
We would appreciate any comments which you or your staff would
like to provide for implementation into our Draft Fish and
Wildlife Coordination Act Report which is presently scheduled
to be written some time during this fiscal year.
Sincerely yours,
L*z--?
L.K. Mike Gantt
Supervisor

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U.S. DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
Raleigh Field Office
551 F Pylon Drive
Post Office Box 33726
Raleigh, North Carolina 27636-3726

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WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
PLANNING AID REPORT
Prepared by
Karen R. Warr
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Under the Supervision of
L.K. Mike Gantt
Supervisor
Released by
U.S. Fish and Wildlife Service
Raleigh, North Carolina
October 1992

TAKE ?? i
MDE IN
United States Department of the Interior
FISH AND WILDLIFE SERVICE
Raleigh Field Office ¦
Post Office Box 33726
Raleigh, North Carolina 27636-3726
October 26, 1992
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Colonel Walter S. Tulloch
District Engineer
U.S. Army Corps of Engineers
P.O. Box 1890
Wilmington, North Carolina 28401-1890
Dear Colonel Tulloch,
Attached is the Service's Planning Aid Report for the
Wilmington Harbor Ocean Bar Channel Deepening Reevaluation
Study. This report identifies fish and wildlife resources
located within the project area and gives a preliminary
discussion of potential impacts to these resources.
The Service is very concerned that blasting will be required
in order to remove rock from underneath the channel. If
blasting is required, it will result in the mortality of an
undetermined number of organisms within the vicinity,
potentially including Federally-listed endangered and
threatened species such as northern right whales, shortnose
sturgeon, and loggerhead sea turtles. We strongly believe that
blasting should be avoided if at all possible.
We are also concerned that further saltwater intrusion up
the Cape Fear River may result from deepening the Ocean Bar
Channel and appropriate mitigation which considers both habitat
value and quantity, should be implemented to offset the
expected resulting loss of forested wetlands. A mitigation
plan designed to address the cumulative loss and conversion of
forested wetlands resulting from all Wilmington Harbor dredging
activities is needed.
A potentially very beneficial use of the rock removed from
underneath the channel would be for creation of an artificial
reef, if the rock is of suitable size to stack, is not
contaminated, and if fine materials are not dumped with the
rock. Creation of artificial reef would be a very positive
action by the Corps. An artificial reef created with natural
rock would provide substrate for marine organisms to attach and
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grow, would provide excellent foraging habitat and would serve
as a refuge for fish and other organisms.
We are pleased that the Corps is working towards avoiding
blasting and is considering using rock from the channel for
artificial reef creation and sand from the channel for beach
nourishment.
We appreciate the opportunity to provide this planning aid
information, and we look forward to continued involvement in
the planning for this proposed project.
Sincerely,
L.K. Mike Gantt
Supervisor
0

I
TABLE OF CONTENTS
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Introduction 1
Purpose, Scope and Authority 1
Prior Studies 2
Study Site Description 2
Existing Fish and Wildlife Resources 6
Marine and Estuarine Waters 6
Intertidal Oyster Reefs g
Intertidal Flats g
Marsh g
Forested Wetlands 9
Colonial Waterbird Islands 9
Barrier Island Communities 10
Intertidal Beach 10
Upper Beach and Berm 10
Dunes 10
Maritime Shrub Thicket/Forest 11
Federally-Listed Endangered and Threatened Species 11
Future of Fish and Wildlife Resources Without the Project 14
Description of Potential Alternatives 15
Description of Impacts 16
Rock Removal and Dredging 16
Disposal of Material Removed from Channel 19
Comparison of Alternatives 20
Fish and Wildlife Conservation Measures 22
Recommendations 24

Fish and Wildlife Service Needs for the Fish and Wildlife
Coordination Act Report 25
Summary
Literature Cited
25
26
FIGURES

0
Figure 1: Study Area Showing Wilmington Harbor
Ocean Bar (Baldhead Shoal) Channel, Bald
Head Island and Oak Island 3
Figure 2: Wilmington Harbor Ocean Bar (Baldhead Shoal)
Channel and Other Channels in the Area 5

INTRODUCTION
Purpose, Scope and Authority
The purpose of this report is to provide planning aid
information for the Wilmington Harbor Ocean Bar project being
conducted by the U.S. Army Corps of Engineers, Wilmington
District. This Planning Aid Report is provided in accordance
with provisions of the Fish and Wildlife Coordination Act (48
Stat. 401, as amended; 16 U.S.C. 661-667d) and pursuant to the
Fish and Wildlife Service's responsibilities under the Scope of
Work Agreement for FY 92. This report does not constitute the
final report of the Secretary. of the Interior as required by
Section 2(b) of the Fish and Wildlife Coordination Act.
The project involves the deepening of the Wilmington Harbor
Ocean Bar Channel, also called the Baldhead Shoal Channel, to
its authorized depth of 40 feet plus overdepth. Three
alternatives are being considered for the amount of required
overdepth: 4 feet, 3 feet and 2 feet. In addition, the
dredging contractor may utilize another 2 feet of allowable
overdepth. The project is authorized by the Rivers and Harbors
Act of 1962 and is described in Senate Document No. 114, 87th
Congress, 2nd Session.
Between 1968 and 1973, the channel was widened and deepened.
Although the deepening was authorized to 40 feet, unanticipated
rock was encountered preventing deepening past 38.5 feet. An
inaccurate tide gage led the Corps to believe the channel was
actually 40 feet deep. However, when the tide gage was
replaced two years ago, the actual depth of 38.5 feet was
revealed. Due to rapid shoaling in the area, the current depth
of 38.5 feet is available only 50 percent of the year, and
approximately 1 foot less is available in the Ocean Bar Channel
the remainder of the year. Vessels require approximately 2
feet more clearance in the Ocean Bar Channel than in the river
channels due to wave action. The North Carolina State Port
Authority and vessel pilots have requested a deeper bar channel
so that rock outcroppings can be avoided and the overall
efficiency of navigation through Wilmington Harbor can be
improved. The Corps is conducting a Reevaluation Study to
assess correcting the deficiency of the depth of the Ocean Bar
Channel.
The purpose of this report is to describe the fish and wildlife
resources within the study area, to assess the potential
impacts to fish and wildlife resources, to discuss fish and
wildlife resource problems and conservation opportunities, and
to recommend measures to conserve fish and wildlife resources.
1
Prior Studies
Related projects include those Corps studies associated with
other sections of Wilmington Harbor. The Corps has prepared a
Reconnaissance Level Study, and a Draft Feasibility Study for
the Wilmington Harbor Turns and Bends Project - the widening of
six channel turns and bends (U.S. Army Corps of Engineers
[hereafter USACOE] 1989a, USACOE 1990a). The Service also
prepared a Planning Aid Report and Draft Fish and Wildlife
Coordination Act Report for the Turns and Bends Project (U.S.
Fish and Wildlife Service [hereafter USFWS] 1989, and USFWS
1991). The Corps prepared a Draft Reconnaisance Report and the
Service prepared a Planning Aid Report and a Draft Fish and
Wildlife Coordination Act Report for the Wilmington Harbor
Passing Lane Project (USACOE 1988, USFWS 1988a, and USFWS
1990). These two projects are now being included in the
Wilmington Harbor Comprehensive Study. The Wilmington Harbor
Comprehensive Study will focus on widening and deepening
projects in the harbor along its entire length from the ocean
Bar Channel to a point on the Northeast Cape Fear River
approximately 1.7 miles upstream of the Hilton Railroad Bridge
above Wilmington (USACOE 1991).
Wilmington Harbor-Northeast Cape Fear River navigation projects
are also relevant. The most recent of these are the Final
Supplement to the Final Environmental Impact Statement (USACOE
1990b) and the Final Fish and Wildlife Coordination Act Report
(USFWS 1988b). The Corps also has prepared the Final
Environmental Impact Statement for Long-Term Maintenance of
Wilmington Harbor, North Carolina (USACOE 1989b).
An Environmental Assessment and Finding of No Significant
Impact for Maintenance Dredging in Wilmington Harbor Ocean Bar
Channels was prepared by the Corps (USACOE 1991a). Bald Head
Island Beach nourishment was discussed in the Wilmington
Harbor-Bald Head Island Evaluation Report (USACOE 1990c).
For the current project - Wilmington Harbor Ocean Bar Channel
Deepening, the Corps has provided a Reevaluation Report which
concluded that the improvements are economically feasible and
can be implemented without additional Congressional
authorization (USACOE 1991b). They are currently preparing an
Environmental Assessment for the project.
STUDY SITE DESCRIPTION
The study area is located in southeastern North Carolina off
the coast of Brunswick County (Figure 1). The Wilmington
Harbor Ocean Bar Channel is located at the mouth of the Cape
Fear River between Bald Head Island to the east and Oak Island
2
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TO WILMINGTON
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ATLANTIC OCEAN
FIGURE 1 - STUDY AREA SHOWING WILMINGTON HARBOR OCEAN BAR
(BALDHEAD SHOAL) CHANNEL, BALD HEAD ISLAND AND OAR ISLAND.
r
to the west. Bald Head Island is actually part of a three
island complex known as Smith Island Complex. The town of
Southport lies landward of the channel to the northwest.
Wilmington Harbor is divided into several channels. The outer,
seaward portion is called the Baldhead Shoal or Ocean Bar
Channel. Moving upriver toward Southport, the other channels
are the Smith Island Channel, Baldhead-Caswell Channel,
Southport Channel, and Battery Channel (Figure 2). At
Southport, the channel turns northward and extends up to the
port of Wilmington. The port of Wilmington is located
approximately 26 river miles upstream from the mouth of the
river.
The ocean bar channel is about 38.5 feet deep below mean low
water (mlw) and 500 feet wide. The channel is approximately
24,000 feet long and oriented in a northeast-southwest
direction. From the upstream limit of the ocean bar channel to
Southport, the authorized depth of 40 feet has been reached.
Between Southport and Wilmington, a 38-foot deep by 400-foot-
wide channel is available. Salinities around the mouth of the
Cape Fear River are generally greater than 10 parts per
thousand (ppt) during spring, and they increase to about 32 ppt
by fall (Schwartz et al. 1979). Saline water reaches a
considerable distance up the Cape Fear River as a result of
dredging activities and sea level rise. During the past
century, drastic changes in community structure have occurred
as saltwater intrusion has converted freshwater wetlands into
salt marsh in the middle reaches of the estuary and into
oligohaline marshes in the upper reaches of the estuary. The
salt marshes of the lower reaches of the estuary have not
changed (Hackney and Yelverton 1990).
The channel is underlain by bedrock. Limestones of either the
Eocene Castle Hayne type or the Cretaceous Peedee Formation lie
at the top of the rock. The precise thickness and extent of
these rock types is unknown under the channel. The thickness
of the rock types and the hardness may vary considerably along
short distances. In some areas the Castle Hayne limestone may
be cemented and in other sections, it may be softer and easier
to break (Bill Hoffman, North Carolina Geological Survey,
personal communication, August 1992). The upper layer of the
Peedee formation limestone is generally harder than the Castle
Hayne formation (USACOE 1991b). Rock from both the Castle
Hayne limestone and the Peedee formation has required blasting
in other portions of the Cape Fear River.
4

?%- BATTERY ISLAND

? ??: --SOUTHPORT

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CAS'
Oak Island 11
SMITH ISLAND"\

DHEAD SHOAL 77 IV
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?C OCEAN
_ Channel to Be Deepened
4000 2000 0 4000 8000
SCALE IN FEET (1:50. 000)
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WILMINGTON HARBOR. NORTH CAROLINA
WILMINGTON HARBOR
BAR CHANNEL
FIGURE 2 - WILMINGTON HARBOR OCEAN BAR (BALDHEAD SHOAL)
CHANNEL AND OTHER CHANNELS IN THE AREA
" Source: U.S. Army Corps of Engineers 1991b.
EXISTING FISH AND WILDLIFE RESOURCES
The ocean bar channel includes both estuarine and marine waters
as well as terrestrial and wetland communities associated with
nearby barrier islands, dredged material disposal islands, and
the mainland areas bordering the Cape Fear River. The
following habitats may potentially be affected by the project
and are discussed in this report: marine and estuarine waters;
estuarine intertidal oyster reefs; intertidal flats; marsh
communities; forested wetlands; colonial waterbird nesting
islands; and barrier island communities categorized as
intertidal beach, upper beach, dunes, and maritime shrub
thicket/forest. Fish and wildlife resources are discussed for
these habitats. Nomenclature of species follows the following
sources: plants - Radford et al. (1968), fish - American
Fisheries Society (1980) and other vertebrates - Banks et al.
(1987).
Marine and Estuarine Waters
Trawling surveys conducted as part of a study concerning the
effects on aquatic resources of the Carolina Power and Light
nuclear power plant in Southport, demonstrate that the Cape
Fear River and nearby ocean waters are utilized by a diverse
group of invertebrates and fish species (Schwartz et al. 1979).
Most abundant invertebrate species were arthropods, such as the
blue crab (Callinectus sapidus), the lesser blue crab
(Callinectus similis), mantis shrimp (Squilla empusa), paneid
shrimp (Paneid aztecus, P.duorarum, P. setiferus), and grass
shrimp (Palaemonetes sp.); echinoderms, such as the common sea
star (Asterias forbesi) and sand dollar (Mellita
quinquiesperforata); jellyfish (Scyphozoan sp.) and other
cnidarians; comb jellies (Ctneophora); and various mollusks
such as oysters (Crassostrea virginica), Atlantic brief squid
(Lolliguncula brevis), conchs and whelks (Melongenidae), and
mud snails (Nassariidae). Many other invertebrate species were
found in smaller numbers.
Gill net and trawling surveys for 1973 through 1977 indicate
that the most abundant fish species in the Cape Fear River
Estuary and nearshore ocean waters were menhaden (Brevoortia
tyrannus), spot (Leiostomus xanthurus), grey trout (Cynoscion
regalis), spotted hake (Urophycis regius), Atlantic croaker
(Micropogon undulatus), star drum (Stellifer lanceolatus),
anchovies (Anchoa spp.), summer flounder (Paralicthys
dentatus), and southern flounder (Paralicthys lethostigma).
Many of these are estuarine dependent species, spawning
offshore and moving into the estuarine waters as larvae. The
Ocean Bar channel is likely a migration route for these species
6
J
as they move into the estuary as larvae and as they migrate
back into the ocean as juveniles or adults. Some estuarine
species are very important prey for larger fish. Mummichog
(Fundulus heteroclitus) and killifish (Fundulus sp.) are a
major prey for game fishes such as striped bass and bluefish.
They spawn in the upper intertidal zones of estuaries.
Anadromous species such as alewife (Alosa pseudoharengus) and
American shad (Alosa sapidissima) move up rivers into fresh or
brackish water to spawn. The shortnose sturgeon (Acipenser
brevirostrum) is an anadromous species which is known to
inhabit the Cape Fear River estuary. This species is Federally
listed as endangered. Although it is known that the species
occurs in the Cape Fear River, the extent of the population is
unknown. It is likely that the species utilizes the Cape Fear
River mouth as it migrates to and from the ocean, but this has
not been confirmed (Steve Ross, University of North Carolina at
Wilmington, Center for Marine Science Research, personal
communication, August 1992).
Marine mammals occur in offshore and inshore waters of North
Carolina. Some species occur farther offshore than project
limits, and others occur in the waters closer to shore. The
sperm whale (Physeter macrocephalus) is a year round resident
of the shelf edge and pelagic waters off North Carolina,
probably moving farther offshore during the winter. The
Federally-endangered right whale (Eubalaena glacialis) and
humpback whale (Megaptera novaeangliae) are spring and fall
migrants off of North Carolina. Both species may be found in
nearshore waters, and the right whale appears to prefer shallow
waters. Although the following species are generally found in
deeper waters, limited beach strandings have been recorded in
North Carolina for these species: dwarf sperm whale (Kogia
simus), pygmy sperm whale (Kogia breviceps), True's beaked
whale (Mesoplodon mirus), killer whales (Orcinus orca), short-
finned pilot whales (Clobicephala melas), and spinner dolphins
(Steno longirostris). Bottlenose dolphins (Tursiops truncatus)
and harbor porpoises (Phocoena phocoena) utilize nearshore
waters including bays, estuarine creeks, and sounds. They are
the most common cetaceans in the area. Bottlenose dolphins are
found in the estuarine waters between Bald Head Island and
Southport.
Five sea turtles inhabit the coastal and offshore waters of
North Carolina. The loggerhead sea turtle (Caretta caretta) is
the most common in the coastal area as it regularly nests on
North Carolina beaches. Most sightings of Kemp's ridley sea
turtles (Lepidochelys kempi) have been within a few miles of
shore. During the 1992 nesting season, a Kemp's ridley sea
7

turtle nested on Long Beach to the south of the study site
(Therese Conant, Sea Turtle Coordinator, N.C. Wildlife
Resources Commission, personal communication, July 1992).
Green sea turtles (Chelonia mydas) have been observed in North
Carolina sound waters, and one has been documented to have
nested on Bald Head Island. The hawksbill sea turtle
(Eretmochelys imbricata) is rare north of Florida, but there
have been limited sightings off the North Carolina coast. The
leatherback sea turtle (Demochelys coriacea) is found between
10 to 30 miles offshore during April through October and
seldomly comes closer into shore (U.S. Minerals Management
Service [hereafter USMMS] 1990).
American alligators (Alligator mississippiensis) are known to
occur in the Cape Fear River and surrounding habitats.
Alligator tracks have been observed on dredge disposal islands
near the project site, and a few alligators inhabit Bald Head
Island.
Intertidal Oyster Reefs
The intertidal estuarine areas in the project vicinity support
extensive oyster reefs in some locations such as around Zekes
Island, north of Bald Head Island. Oyster reefs support a
valuable fishery in the area, and the reefs are inhabited and
utilized by many species of invertebrates, fish, and birds.
Other intertidal habitats in the area include intertidal flats
and marsh communities.
Intertidal Flats
Intertidal flats support burrowing invertebrates, such as
jacknife clams (Tagelus spp.) and various polychaetes, such as
the plumed worm (Diopatra cuprea). These invertebrates are
prey for fish which forage over the intertidal flats when they
are submerged and for numerous other animals such as American
oystercatchers (Hemitopus palliatus), black-bellied plovers
(Squatarola squatarola), gulls (Larus sp.), dunlin (Caladris
alpina), western sandpipers (Calidris mauri) and raccoons
(Procyon lotor) when the flats are exposed or when water levels
are low.
Marsh
Marshes are highly productive, essential components of
estuarine and marine food webs. They serve as nursery areas
for many fishery species and are utilized by numerous birds,
and various mammals and reptiles. Marsh communities within the
project site are of two main types: smooth cordgrass (Spartina
8
alterniflora) marsh and black needlerush (Juncus roemerianus)
marsh. Along the margins of the Cape Fear River near the
mouth, the marsh is primarily dominated by smooth cordgrass.
Other species of this community include sea lavender (Limonium
carolinianum), sea oxeye (Borrichia frutescens), saltwort
(Salicornia virginica), and salt meadow cordgrass (Spartina
patens). Farther upstream in the middle portions of the
estuary and within interior portions of Bald Head and other
islands, black needlerush marsh, a brackish community is found.
These black needlerush marshes have replaced forested wetlands
due to increased tidal amplitude and saltwater intrusion.
Saltwater intrusion has occurred as a result of dredging
activities in the harbor channels and the creation of Snow's
Cut, a channel cut between the Atlantic Intracoastal Waterway
and the Cape Fear River, allowing saltwater from Carolina Beach
Inlet to move up the river. Within the upper reaches of the
estuary, oligohaline marsh is found. Here salinities range
from 0 to 5 parts per thousand. Cattail (Typha spp.), big
cordgrass (Spartina cynosuroides), and wild rice (Zizania
aquatica) are a few of the plants. Dead cypress trees are
found within these oligohaline marshes.
Forested Wetlands
Wooded swamps occur in areas above the influence of salt water.
The most abundant trees are bald cypress (Taxodium distichum),
black gum (Nyssa sylvatica var. biflora), red maple (Acer
rubrum), and Carolina ash (Fraxinus caroliniana). As saline
water reaches farther upstream, wooded swamp vegetation is
dying and being replaced by oligohaline marsh.
Colonial Waterbird Islands
The lower Cape Fear River estuary is one of the most important
colonial waterbird nesting locations in North Carolina.
Battery Island, located to the northwest of Bald Head Island is
a natural estuarine island owned and managed by the National
Audubon Society. The island contains dense maritime shrub
thicket vegetation which has supported a mixed-species nesting
rookery since at least 1928. It is used by glossy ibis
(Plegadis falcinellus), white ibis (Eudocimus albus), cattle
egret (Bulbulcus ibis), little blue herons (Florida caeurlea),
and other waders. Battery Island contains two separate
colonies - the north colony and the south colony. Collectively
they form the largest wading bird nesting population in North
Carolina (Parnell and Shields 1990). Several dredged material
disposal islands along the lower Cape Fear River are also used
9
as nesting sites by colonial waterbirds. North and South
Pelican Islands and Ferry Slip Island are closest to the study
site and are used by brown pelicans (Pelecanus occidentalis),
royal terns (Sterna maxima), and laughing gulls (Larus
atricilla). Black skimmers (Rynchops niger), common terns
(Sterna hirundo) and gull-billed terns (Gleochelidon nilotica)
also nest on Ferry Slip Island. South Pelican Island and Ferry
Slip Island support nearly one half of the State's brown
pelican breeding population (Parnell and Shields 1990).
Barrier Island Communities
Barrier Island communities on Bald Head Island and Oak Island
are discussed in this report because they may potentially be
affected by the project. These include: intertidal beach,
upper beach or berm, sand dunes, and maritime shrub
thicket/forest.
Intertidal Beach
The intertidal beach is inhabited primarily by coqunia clams
(Donax variablis and Donax parvulus), mole crabs (Emerita
talpoida), and probably amphipods, such as Haustorius species.
Polychaetes and nematodes also may be important inhabitants
(Van Dolah and Knott, 1984). These invertebrate species are
important prey to fish and shorebirds, such as sanderlings
(Crocethis alba), black-bellied plovers and Eastern willets
(Catoptrophorus semipalmatus).
Upper Beach or Berm
The upper beach or berm is located between the high tide
line and the dune line and is largely unvegetated. Scattered
clumps of dune building species such as sea rocket (Cakile
edentula) and possibly seabeach amaranth (Amaranthus pumilus),
a Federally-proposed threatened species, are found in this
area. These plants serve as building blocks of dunes by
trapping sand. The upper beach is important nesting habitat
for loggerhead sea turtles and for shorebirds, such as Eastern
willets and American oystercatchers, and potentially for the
Federally-listed threatened piping plover (Charadrius melodus).
Dunes
The dune community is vegetated primarily by sea oats
(Uniola paniculata) and broomsedge species. (Andropogon sp.)
with scattered beach pea (Strophostyles helvola), pennywort
(Hydrocotyle bonariensis), sandspur (Cenchrus tribuloides), sea
rocket (Cakile edentula), seaside croton (Croton punctatus),
10
beach spurge (Euphorbia polygoniflora), evening primrose
(Oenothera humifusa), and seaside elder (Iva imbricata). Sand
dunes provide habitat for red wing blackbirds (Agelaius
phoeniceus), seaside sparrows (Ammospiza maritima), rice rats
(Oryzomys palustris), raccoons (Procyon lotor), lizards and
snakes and various other animals. They provide protection to
maritime scrub-shrub/forest habitats and other communities and
structures located landward of them.
Maritime Shrub Thicket/Forest
Maritime shrub thicket/forest habitats are vegetated by salt
spray tolerant species such as live oak (Quercus virginiana),
wax myrtle (Myrica cerifera), yaupon (Ilex vomitoria), Eastern
red cedar (Juniperus virginiana), and catbriar (Smilax
species). Closer to the stressful salt and wind influences, a
shrub thicket community exists with dense shrubs, vines and
stunted live oak trees dominating. Further away from the harsh
salt and wind influences, the shrub thicket grades into a
maritime forest. The maritime forest is generally less stunted
and has a higher plant diversity. Less salt tolerant deciduous
trees may occur in the interior portions of the maritime
forest. only few relict tracts of maritime forests are left in
North Carolina. Bald Head Island contains an extensive
maritime forest supporting the most northerly natural saw
palmetto (Serenoa repens) population along the east coast.
Maritime forests are very important resting and foraging
habitats for migratory birds, and they are also heavily used by
resident species of birds, snakes, amphibians, mammals and fish
where freshwater ponds are found. Bald Head Island maritime
forests have been categorized as having "...much higher than
average ecological diversity compared to most remaining
maritime forests...and the maritime forest community is
described as "...one of the best remaining maritime forests for
rare species habitat..." (North Carolina Coastal Resources
Commission 1990).
Federally-listed Endangered and Threatened Species
The following Federally-listed threatened and endangered
species may be found within the project area or in areas
potentially affected by the project:
loggerhead sea turtle (Caretta caretta) - Threatened
green sea turtle (Chelonia mydas) - Threatened
Kemp's ridley sea turtle (Lepidochelys kempii) - Endangered
leatherback sea turtle (Dermochelys coriacea) - Endangered
hawksbill sea turtle (Eretmochelys imbricata) - Endangered
shortnose sturgeon (Acipenser brevirostrum) - Endangered
11
Florida manatee (Trichechus manatus) - Endangered
piping plover (Charadrius melodus) - Threatened
American alligator (Alligator mississippiensis) - Threatened
by Similarity of Appearance
Northern right whale (Eulabaena glacialis) - Endangered
humpback whale (Megaptera novaeanglia) - Endangered
The most common sea turtle in the study area is the loggerhead
which nests on ocean beaches adjacent to the project area. The
ocean beaches at Bald Head Island are the most highly used
beaches for loggerhead nesting in North Carolina. Over 100
nests are recorded each year. and as many as 193 nests have
occurred in one year (Dr. William David Webster, University of
North Carolina at Wilmington, personal communication, may
1992). This species is found within offshore and inshore
coastal waters including sounds between April through November.
Another Federally-listed threatened sea turtle, the green sea
turtle, has nested on Bald Head Island, although this was an
isolated occurrence (Kelly Cook, Bald Head Island Nature
Conservancy, June 1992). On June 17, 1992 a Kemp's ridley sea
turtle, an endangered species, nested on Long Beach, the
southern section of Oak Island, just to the south of the study
site. This positive identification is the first record of the
species nesting in North Carolina. However, two other
descriptions of sea turtles nesting in North Carolina during
the 1992 season fit the description of the Kemp's ridley
turtles (Therese Conant, Sea Turtle Coordinator, N.C. Wildlife
Resources Commission, personal communication, August 1992).
Loggerhead, Kemp's ridley, green, leatherback and hawksbill sea
turtles may occur within the nearshore waters of the project
area. However, the hawksbill sea turtle is generally not seen
north of Florida, but limited sightings of this species off the
North Carolina coast have occurred.
Northern right whales and humpback whales may also be found in
the nearshore waters within the boundaries of the project.
Both species are Federally-listed as endangered. The Northern
right whale is in serious danger of extinction within the
foreseeable future. The population has not increased
significantly in size since commercial harvests ended over 50
years ago. Northern right whales migrate off the coast of
North Carolina during spring and fall. Most nearshore
sightings have been between January through May. Generally,
sightings occur very near the shoreline. Humpback whales are
believed to migrate offshore North Carolina during spring
12

migration, April and May, and fall migration, September through
December. They are generally found in waters between 66 and
240 feet deep, out of the limits of this project (USMMS 1990).
Shortnose sturgeon occur in the Cape Fear River. However,
their presence within the ocean bar channel area is unknown.
Adults probably migrate through the area as they move from
ocean to fresh water areas for spawning and as they return to
the ocean, but this has not been documented (Steve Ross,
University of North Carolina at Wilmington, Center for Marine
Science Research, personal communication, August 1992). It is
possible that the Cape Fear River population does not actually
make ocean runs but just migrates from upriver sites to the
lower reaches of the estuary between spawning periods (Dr. Mary
Moser, personal communication, August 1992). This is known to
occur in some northern populations of sturgeon. Shortnose
sturgeon begin to migrate up the Cape Fear River during late
December, but it is not known whether this population is
returning from the ocean and, is thus passing through the ocean
bar channel area, or if the population remains year round in
the estuary. The time period during which channel deepening is
least likely to result in impacts to the sturgeon is difficult
to determine based on the limited data available. According to
Dr. Moser, late August through September would probably be the
best time for work assuming the sturgeon moves from the ocean
to the estuary (Dr. Mary Moser, personal communication, August
1992).
The National Marine Fisheries Service has responsibility for
Federally-listed marine and anadromous species, including sea
turtles when "in the water." They should be contacted
regarding any endangered and threatened marine or anadromous
species which may be affected by the project.
The piping plover is a Federally-listed threatened species.
This species' decline is attributed to increased development
and recreational activities on beaches. Vehicle and foot
traffic on beaches can directly crush eggs and chicks or
indirectly lower productivity by disrupting territorial
establishment and breeding behavior. Increased development of
beach areas also has resulted in an increase in plover chick
and egg predators, such as gulls and racoons.
Piping plovers prefer upper edges of overwash areas at inlets
or large open unvegetated beaches for nesting. While there has
been no documentation of piping plovers nesting on Bald Head
Island, suitable piping plover habitat may exist on the island.
Three piping plover nests were observed on Holden Beach at the
western end of Oak Island during the 1992 season, but none of
13

these nests were successful. Piping plovers have also used Oak
Island during winter and migration (Tom Henson, N.C. Wildlife
Resources Commission, personal communication, August 1992).
Seabeach amaranth (Amaranthus pumilus) has been proposed for
listing as threatened. It generally occurs in large barren
areas of extreme overwash, often near inlets. Where found,
seabeach amaranth grows between dunes and the high tide line
and helps to trap sand and build dunes.
Candidate species are those which, although not now listed or
officially proposed for listing as endangered or threatened,
are under status review by the Service. These "Candidate" (Cl
and C2) species are not legally protected under the Act and are
not subject to any of its provisions, including section 7,
until they are formally proposed or listed as threatened or
endangered. These species may be listed in the future at which
time they will be protected by the Act. In the meantime, we
would appreciate anything you might do for them. The only
candidate species which may occur within areas covered by this
project is dune blue curls (Trichostema dichotomum). Dune blue
curls utilizes high dunes and grasslands behind primary dunes.
FUTURE OF FISH AND WILDLIFE RESOURCES WITHOUT THE PROJECT
It is necessary to distinguish between changes in the fish and
wildlife resources which will likely occur without the project
and those expected as a result of the project. To accomplish
this, a discussion of anticipated future conditions of fish and
wildlife resources without the project, is presented.
Periodic maintenance of the Ocean Bar channel and other
channels of Wilmington Harbor will continue to temporarily and
periodically increase turbidity in the waters, resulting in
physiological stress and mortality to some aquatic species, and
will continue to periodically disturb the benthos of channel
bottoms. Development and alteration of terrestrial and wetland
communities on mainland and barrier islands is occurring and is
expected to continue. Golf courses on Bald Head Island will
continue to be managed and landscaped and as a result of these
activities, nonpoint source runoff may result in further
declines in water quality of adjacent waters. However, the
study area is expected to remain high value habitat for
estuarine dependent fishery species which will continue to use
local waters for feeding, spawning, and as nursery habitat.
Marine mammals and sea turtles are expected to continue to use
the study waters. Colonial nesting waterbird islands in the
area will continue to support nesting bird populations as long
14
as management of the islands continues; including disposal of
dredged-material when needed.
Past Wilmington Harbor Channel construction activities and the
creation of Snows Cut connecting the Atlantic Intracoastal
Waterway with the Cape Fear River, along with continued sea
level rise, have resulted in increased tidal amplitudes and
saltwater intrusion up the Cape Fear River. The estuary's
freshwater wooded swamps are being converted into salt,
brackish and oligohaline tidal marshes. Dredging activities
within the Cape Fear River, such as the widening of a turning
basin and the construction of a passing lane, will likely
result in further intrusion of-saltwater into the upper reaches
of Wilmington Harbor.
Beach nourishment occurred on Bald Head Island during 1991, and
this activity may continue annually or less frequently in the
future. A 50-year plan for annual beach nourishment has been
prepared by the Corps. However, annual approval will be
required. Beach erosion is severe on Bald Head Island and with
sea level rising, with the continued use of the Wilmington
Harbor channels by large ships, and with maintenance dredging
of the Wilmington Harbor channels occurring, erosion is
expected to continue and to increase in the future. Sea turtle
habitat and potential piping plover habitat may be reduced as a
result. Although certain areas of Bald Head Island may
experience severe erosion, the island is expected to remain
very important nesting habitat for the loggerhead sea turtle.
DESCRIPTION OF POTENTIAL ALTERNATIVES
The proposed alternatives involve deepening the channel so that
a 40 foot depth is maintained throughout the year along the
entire channel. Due to rapid shoaling of the channel and to
limit maintenance dredging to once a year, an overdepth zone is
required in order to maintain the year-round 40 foot depth
(Figure 2). The alternatives vary in the amount of required
overdepth proposed as follows: Alternative A - 40 feet + 4 feet
required overdepth + 2 feet allowable overdepth; Alternative B
- 40 feet + 3 feet required overdepth + 2 feet allowable
overdepth; Alternative C - 40 feet + 2 feet required overdepth
+ 2 feet allowable overdepth. Resulting depths of the channel
for Alternatives A, B and C would be 46, 45, and 44 feet,
respectively. Alternative A is the Corps' tentatively selected
plan.
For alternative A, the entire 24,000 feet of the Ocean bar
channel would be deepened to 40 feet plus 4 feet required
overdepth and 2 feet of allowable overdepth. This means the
15
actual depth of the channel would be between 44 to 46 feet.
The Corps states that the 4 feet of required overdepth is
necessary in order to "...prevent immediate shoaling of the
channel after construction since the channel prism will be
excavated from rock" (USACOE 1991b). The plan would involve an
extension of the channel into the Atlantic Ocean to a point
where natural depths are equal to the channel depth. This
would result in the seaward extension of approximately 12,000
feet. A 500-foot width and a slope of 1 vertical to 5
horizontal (1:5) would be maintained in areas of unconsolidated
soft material. Side slopes in rock areas would be kept steep
in order to limit the amount of rock requiring removal. A side
slope of 1:1 should be suitable according to the Corps (USACOE
1991b).
Initial deepening will require the removal of 2,376,230 cubic
yards (cy) of limestone rock and 904,170 cy of sand. The sand
would be removed by hopper
dredge, and the rock would be removed with a cutterhead
pipeline dredge or will require blasting. If blasting is
necessary, a bucket and barge dredging system will remove the
rock after blasting and dispose of the material. If a
cutterhead dredge is used, then a scow may be used to carry the
material to its destination. The Corps is currently evaluating
the feasibility of using a cutterhead dredge for the rock
removal.
The material may be dumped at the Wilmington Harbor Offshore
10 Dredged Material Disposal Site (ODMDS) located about 4 miles
east of the channel or the rock may be used to create
artificial reef habitat and sand may be used for nourishment of
nearby beaches. Project maintenance would involve annual
dredging of an additional 36,900 cy of sand over the amount
presently dredged during maintenance activities.
If blasting is necessary, drilling and blasting would be
performed from a floating barge. Water gel explosives will be
used.
DESCRIPTION OF IMPACTS
Rock Removal and Dredging
The potential need for blasting in order to remove rock
underneath the channel is of utmost concern to the Service.
Blasting will result in the mortality of fish, marine mammals
and sea turtles and other life within a certain radius of the
explosion. The lethal range will depend on the type of
explosives used and the methods of blasting. These have not
16
0
been identified by the Corps at this time. The lethal zone for
an underwater charge of 100 pounds per delay with detonation
velocity ranges from 4,000 to 231000 feet per second has been
shown to be approximately a 600 feet radius around the blast
(Linton et al. 1985). However, the actual lethal range will be
affected by other factors. Confinement of explosives in rock
may reduce the explosive pressure in water by a factor of 10.
Linton et al (1985) estimate that a high detonation velocity
explosion that produces a peak pressure of 40 pounds per square
inch will kill fish. Blasting may result in the mortality of
northern right whales, short-nosed sturgeon, and sea turtles as
well as anadromous fish and larvae of estuarine dependent
species. It will be very difficult to assess the species and
the number of organisms lost as a result of blasting.
Removal of rock using a cutterhead dredge will result in
mortality of benthos, plankton, and nekton unable to escape the
dredge. Larvae are particularly vulnerable because many are
flowing freely with the currents and are likely to be sucked up
by the dredge. Although some adults would also be swept up by
the dredge, most should be able to avoid it. Sea turtles and
right whales should be able to avoid impact from the hydraulic
cutterhead pipeline dredge. The most critical time period for
larval fish moving through the estuary is between January
through April, and dredging with hydraulic cutterhead dredge
should be avoided during this time.
Soft materials will be removed from the channel with a hopper
dredge. Hopper dredging will result in the mortality of
benthos and other organisms in the path of the hopper. The
November 1991 Sea Turtle Biological Opinion issued by the
National Marine Fisheries Service concerning the use of hopper
dredges, restricts hopper dredge use in channels to the months
of December through March, due to the presence of sea turtles
in the channels during other times of the year. Data collected
aboard dredges in the vicinity of Kings Bay, Georgia indicate
that northern right whales may be vulnerable to collisions with
hopper dredges during the breeding/calving season. While
northern right whales are not known to breed off of North
Carolina, they do migrate through North Carolina waters, and it
is possible that dredges may collide with northern right whales
if precautions to avoid such collisions are not implemented
during the migration season.
Blasting and dredging also will likely result in increased
turbidities in the immediate vicinity potentially clogging the
gills of fish and invertebrates. Turbidity levels will depend
on the amount of fine materials being resuspended.
17
Potential impacts to migrating whales, to sea turtles, to fish
and invertebrates, especially larvae, can be minimized if
deepening activities occur during periods when these organisms
are not utilizing the study area habitat. Blasting will
especially require seasonal restrictions due to the inability
of organisms to escape blasting effects. Finding a suitable
time period for blasting will be difficult because the critical
time periods for whales, sea turtles, larval fish and
anadromous species differ. The most critical time period for
estuarine dependent larvae passing through the areas as they
move into the estuary is between January and April. Whales may
be present during spring migration, and fall migration. They
have been observed most during March and April. Only one
October sighting indicates that they may migrate farther
offshore during the fall. Sea turtles are generally found in
the nearshore and inshore waters between April through
November. It is unknown whether or not shortnose sturgeon
utilize the ocean bar channel area. In the event that the
population of shortnose sturgeon which uses the Cape Fear River
does make an ocean run, then the period least likely to impact
this fish is probably between mid August through September
(Mary Moser, University of North Carolina at Wilmington, Center
for Marine Science Research, personal communication, August
1992).
Deepening the ocean bar channel may increase the tidal
amplitude moving into the Cape Fear River and increase
saltwater intrusion farther upstream. This may result in the
additional conversion of forested wetlands into oligohaline
marsh and more saline environments. Such impacts are difficult
to attribute to particular harbor activities, and the extent of
such habitat conversions is especially difficult to predict.
Habitat conversion of forested wetlands into oligohaline and
salt marsh will benefit fauna adapted to marsh and adversely
affect species depending on forested wetlands, such as black
bear (Ursus americanus), wood duck (Aix sponsa) and songbirds
like the prothonotary warbler (Protonotaria citrea). Further
salt water intrusion will increase the ranges of marine fish
and invertebrates, such as pink shrimp, farther upstream and
prevent the movement of freshwater species downstream.
Deepening of the ocean bar channel also may result in
additional erosion problems to adjacent barrier islands. Deep
channels trap sediments moving through littoral transport along
the coast, and the result is a starvation of sands to adjacent
beaches, especially if the material removed from the channel
during initial and maintenance dredging is deposited outside of
the littoral system. These impacts also are very difficult to
18
N
predict, especially without a detailed understanding of the
sediment budget in the immediate area.
Disposal of Material Removed from Channel
A potential positive use of the rock after removal from the
channel would be to use it for creation of artificial reef
habitat, if the rock is of suitable size to stack, if fine
materials are not dumped with the rock, and if the rock is not
contaminated (Steve Murphy, North Carolina Division of Marine
Fisheries, Artificial Reef Coordinator, personal communication,
August 1992). If silt is deposited along with the rock and the
rock is contaminated, then placing the material at an existing
artificial reef site could result in adverse impacts to fish
already utilizing the reef. Conversely, if of acceptable
quality, it could provide improved habitat.
If material is placed at the Wilmington Harbor ODMDS, benthos
will be buried and turbidity may temporarily increase, but
because the area is already disturbed, impacts would be
minimal. If rock is placed at the ODMDS, then the disposal
site may reach its capacity more quickly requiring a new
disposal site for future dredged material disposal.
Beach nourishment will result in the burial of intertidal
organisms such as coquina clams and mole crabs. If nourishment
occurs in the winter and is completed prior to the Spring
recruitment period, these species should be able to recover.
Reilly and Bellis (1978) state that species recruited from
pelagic larval stocks, such as mole crabs and coquina clams,
will recover if nourishment activity ends before larval
recruitment begins in the spring. Dr. Robert Dolan of the
University of Virginia is presently studying the effects of
beach fill activities on mole crabs at Pea Island National
Wildlife Refuge (NWR). Preliminary results indicate that
nourishment has a dramatic impact on mole crab numbers in the
area where beach fill is placed. Mole crab numbers remain
particularly low for 45 to 60 days after nourishment is
finished. His studies also indicate that nourishment should
not occur during the spring, when mole crab recruitment is
occurring. There is also a high correlation between sediment
size and Emerita numbers, and using course sand grains for
nourishment may result in lasting impacts to Emerita
populations (Dr. Robert Dolan, University of Virginia, personal
communication, June 1992). Beach nourishment will cause
turbidity in the nearshore waters as beach material is washed
off the beach, especially if fine materials are placed on the
beach.
19
Beach nourishment also may cause the burial of sea turtle nests
if carried out during summer months. More indirect effects to
sea turtles such as those caused by beach compaction and
unnatural beach profiles may result from beach nourishment
activities, despite the period of nourishment activities.
Dumping sand on beaches may disrupt nesting sea turtles by
causing sand to compact so tightly that turtles have a
difficult time moving through the sand and digging nests.
Nesting sea turtles more often reject nests sites, make false
crawls and false digs, and excavate atypical nest cavities on
compacted beaches than on natural beaches (Nelson and Dickerson
1988). Compaction may also increase the length of time
required to excavate a nest and thus cause physiological stress
to the turtles (Nelson and Dickerson 1988).
According to Nelson and Dickerson (1988), the level of
compaction of a beach can be assessed by measuring sand
consistencies using a cone penetrometer. Sand consistencies
above about 550 pounds per square inch increased digging times
of sea turtles. Tilling of a nourished beach reduces the
compaction to levels comparable to unnourished beaches. A root
rake with tines at least 42 inches long and less than 36 inches
apart pulled through the sand is recommended (Nelson and
Dickerson 1988).
Often beach nourishment results in a steep escarpment between
the beach fill area and the natural offshore slope. Such a
change in beach profile may cause access problems for nesting
sea turtles or obstruct hatchling sea turtles on their way to
the ocean. Efforts should be made to ensure that the beach
profile after nourishment is a natural, gently sloping beach
rather than a layered beach with sharp escarpments which might
hinder nesting sea turtles as well as hatchlings.
COMPARISON OF ALTERNATIVES
Removal of the rock underlying the channel by blasting with
explosives would result in more severe adverse impacts to fish
and wildlife resources than would the use of a cutterhead
dredge. Blasting would kill all organisms within a certain
radius of the explosions, and the extent of blasting-caused
mortality would be difficult to quantify. Blasting may kill
whales, sea turtles, adult fish and invertebrates, as well as
juveniles and larvae. Mortality caused by the use of a
cutterhead dredge would be more localized, and most adult
organisms would be able to escape the dredge. Both processes
20
r
M
would result in turbidity plumes, depending on the amount of
fine materials being resuspended.
Assuming the entire 2 feet of allowable overdepth is utilized
for the project, the total resulting depths from each
alternative would be 46 feet for Alternative A, 45 feet for
Alternative B, and 44 feet for Alternative C. The potential for
channel deepening to cause or augment erosion on nearby beaches
may be increased the deeper the channel is made. With
increasing depth, the amount of rock requiring removal, and the
time required to complete the project will be increased. The
mortality of fish and wildlife also will be greater, especially
if blasting is required in order to remove the rock. Thus,
Alternative C would result in the fewest impacts to fish and
wildlife resources while Alternative A would result in the most
impacts to fish and wildlife resources.
Possible rock disposal alternatives being considered are the
use of the rock for creation of artificial reef habitat and the
dumping of the rock at the Wilmington Harbor ODMDS. Utilizing
rock from the channel as artificial reef habitat would greatly
enhance fishery resources if the rock is of suitable size to
stack, is not contaminated and if silts are not deposited with
the rock. Artificial reefs provide substrate for marine
organisms to attach and grow, provide excellent foraging
habitat, and become refuges for fish and other organisms.
Dumping the rock at the ODMDS might create hard bottom at the
site, but this would not be a suitable reef location due to
future dumping of dredged material at the site. The ODMDS also
may contain higher levels of pollutants than other areas,
making the ODMDS less suitable as a place for fish to
congregate.
Material dredged from the project, other than rock, may be
dumped at the Wilmington Harbor ODMDS or used for beach
nourishment of adjacent beaches. Disposal of the material at
the ODMDS would remove material from the littoral system and
potentially may accelerate erosion on Bald Head Island or Oak
Island. Material from maintenance dredging of the channel has
been deposited at the ODMDS in the past, and this activity may
have affected the shoreline along Bald Head Island. Further
deepening of the channel may exacerbate erosion on the island
because additional sand may become trapped in the deeper
channel and removed from the littoral zone as it is dumped at
the ODMDS. Use of sandy material as beach nourishment material
for Bald Head Island or Oak Island would help, keep the material
within the littoral zone.
21
i
If beach nourishment activities are carefully designed and
implemented to avoid impacts to nesting sea turtles, nesting
birds, beach invertebrates and nearshore invertebrates and
fish, then nourishment would be a more environmentally
favorable method of disposal of sand than would the dumping of
sand offshore at the ODMDS. Disposal at the ODMDS may be the
best option for disposal of finer materials unsuitable for
beach nourishment.
FISH AND WILDLIFE CONSERVATION MEASURES
Fish and wildlife conservation measures include: 1) mitigation;
and 2) enhancement. Mitigation, as defined by the Council of
Environmental Quality and adopted by the service in its
Mitigation Policy (Federal Register 46[15]: 1656-1662, January
23, 1981) includes: 1) avoiding the impact altogether by not
taking a certain action or parts of an action; 2) minimizing
impacts by limiting the degree or magnitude of the action and
its implementation; 3) rectifying the impact by repairing,
rehabilitating, or restoring the affected environment; 4)
reducing or eliminating the impact over time by preservation
and maintenance operations during the life of the project; and
5) compensating for the impact by replacing or providing
substitute resources or environments. This five action
sequence should be viewed as the proper order for formulating
mitigation measures.
If a cutterhead dredge can be used to cut through the rock
underlying the channel, then many of the major potential
impacts to fish and wildlife resources can be avoided and
minimized. The Service believes the project should be
conducted without the use of blasting if at all possible.
Blasting should be a used only as a last resort. If blasting
must occur, then a strict time frame should be developed which
takes into account the presence of endangered species such as
sea turtles, right whales and shortnose sturgeon. The use of
the channel by anadromous species and estuarine dependent
species also should be considered in developing the blasting
window. Considering the time periods at which shortnose
sturgeon, sea turtles, northern right whales, anadromous
species and estuarine dependent fish and invertebrate larvae
utilize the study area, there is really no suitable time period
for conducting blasting activities. At all times of the year,
blasting may potentially affect one or another species of
concern. It may be possible to use blasting during critical
time periods if other measures are undertaken which will ensure
that mortality of endangered and threatened species is
prevented and mortality of other species is minimized. For
22
N
example, if blasting occurs during the right whale migration
season, whale watching may be used as means to ensure that
blasting does not occur when northern right whales are in the
area. The National Marine Fisheries Service should be
contacted regarding Federally-listed marine and anadromous
species.
Dredging within the channel using a hydraulic cutterhead
pipeline dredge also should involve a window which takes into
account potential impacts to larvae of estuarine dependent
species. If work is avoided during environmentally sensitive
periods of the year, then major direct impacts to fish and
wildlife can be avoided and minimized. Larval fish and
invertebrates are most vulnerable to dredging because many
simply move with the currents while adults can swim out of the
dredge path. The most critical time period for larval fish
moving through the estuary is between January through April,
and dredging with a cutterhead pipeline dredge should be
avoided during this time, if possible (Fritz Rhode, N.C.
Division of Marine Fisheries, Wilmington, NC, personal
communication, August 1992). Unavoidable impacts to the marine
and estuarine bottom can be compensated by creating hard bottom
habitat elsewhere with the rock removed from the channel bottom
if the rock removed is suitable. Artificial reef creation
would enhance fishery resources.
The saltwater intrusion and habitat conversion which has
` occurred and will occur up the Cape Fear River is attributable
at least partially to cumulative impacts of past dredging
activities in Wilmington Harbor. The Service believes the
expected future loss of forested wetlands should involve in-
kind habitat replacement. To do this, the Corps should
estimate the potential losses and replace lost habitat value
through construction of replacement habitats, restoration of
previously altered forested wetlands within the impact areas or
manage and preserve similar habitat to improve its habitat
value so that no net loss of in-kind habitat value occurs. The
Corps should develop and implement a mitigation plan in
response to cumulative salt intrusion/habitat conversion
impacts resulting from past and present Wilmington Harbor
projects.
The potential for the deepening of the channel to accelerate
erosion of nearby beaches may be reduced if sand dredged from
the channel is used for beach nourishment rather than disposing
of the material at the ODMDS outside of the littoral zone.
23

RECOMMENDATIONS
The Service offers the following preliminary recommendations at
this early stage of the planning process. We believe these
statements will assist the Corps in avoiding, minimizing and
mitigating for potential, expected, adverse impacts to fish and
wildlife resources:
1. Remove the rock underneath the channel in the manner which
will result in the fewest impacts to fish and wildlife
resources - using a cutterhead dredge, if possible, rather
than blasting.
2. Use careful time-of-year planning and impact preventative
measures for deepening activities, particularly blasting, if
it is necessary, so as to avoid impacts to sea turtles,
migratory whales, shortnose sturgeon, estuarine dependent
larvae and anadromous species. If blasting is required,
surveys should be made in order to determine the species and
number of organisms killed by the blasts.
3. Assess the suitability of the rock underneath the channel
for artificial reef creation. If the rock will stack
adequately, is not contaminated and if fine materials are
not deposited with the rock, then the creation of artificial
reef habitat will be a positive contribution to fishery
resources of the area.
W
4. Protect nearby beach habitats and limit the amount of sand
removed from the littoral system by: a) deepening the
channel to the minimum depth required to maintain the year-
round 40-foot depth; and, b) using suitable sand for beach
nourishment of eroding adjacent beaches.
5. In order to avoid beach nourishment during the sea turtle
nesting season and during the recruitment period for mole
crabs and coquina clams, nourish the beaches between
December 1 through mid-February, if possible. Till
nourished beaches prior to the sea turtle nesting season if
sand compaction is greater than 500 pounds per square inch,
when tested with a cone penetrometer.
6. If possible, avoid the use of a cutterhead dredge during
January through April, the most critical time period for
larval fish moving through the estuary (Fritz Rhode, N.C.
Division of Marine Fisheries, Wilmington, NC, personal
communication, August 1992).
24

7. Provide an analysis of the expected impacts to forested
wetlands which would result from increased saltwater
intrusion related to the project.
8. Develop and implement a mitigation plan designed to offset
habitat value losses associated with the conversion of
forested wetlands to oligohaline marsh and other habitat
modifications or losses.
Fish and Wildlife Service Needs for the Fish and Wildlife
Coordination Act Report
The Service will prepare Draft and Final Fish and Wildlife
Coordination Act Reports for the project in the near future.
The following information is needed by the Service in order to
adequately assess the potential impacts to fish and wildlife
resources: the feasibility of using a cutterhead dredge rather
than blasting in order to remove the rock within the channel;
anticipated turbidity levels due to blasting and or dredging;
blasting methods, if any, to be used including the anticipated
lethal radius resulting from explosions; time period required
to complete the project; any anticipated increases in tidal
amplitude and salt intrusion up the Cape Fear River resulting
from the deepening project; erosion to barrier islands adjacent
to the channel resulting from past and future dredging
activities; disposal methods to be used including any plans to
create artificial reef habitat; any beach nourishment plans
being considered, including information on compatibility of
natural beach sand with material from the channel to be used
for nourishment; and information on the sediment budget of the
area.
SUMMARY
of utmost concern to the Service is the potential use of
blasting for removal of rock underneath the channel. Blasting
will result in the mortality of fish and invertebrates
including larvae and potentially of right whales, sea turtles,
and shortnose sturgeon if they happen to be within a certain
radius of the blasts. Careful time-of-year planning will be
necessary if blasting is used, but it will be very difficult to
avoid impacts to all species of concern, including Federally-
listed species, due to different critical time periods at which
the species are potentially utilizing the channel and
surrounding waters. If blasting is required, surveys should be
made in order to determine the species and number of organisms
killed by the blasts. Dredging also will result in mortality,
of sessile species and those unable to escape the dredge head.
Seasonal constrictions also will be necessary with dredging,
25
mainly with regard to fish and invertebrate larvae as most
adults should be able to escape the dredge.
Rock removed from the channel should be used for artificial
reef creation if the resulting fragments will be large enough
to stack, if silt deposition can be kept to a minimum, and if
the rock is not contaminated. Artificial reef creation would
benefit fishery resources of the area and be a very positive
action by the Corps.
We believe the Corps should assess the potential saltwater
intrusion up the Cape Fear River resulting from the channel
deepening and assess the potential for the channel deepening to
accelerate erosion on adjacent barrier islands. An appropriate
mitigation plan should be developed and implemented for the
loss of forested wetlands resulting from saltwater intrusion
due to the deepening project. This mitigation plan designed to
address the cumulative loss and conversion of forested wetlands
resulting from all Wilmington Harbor dredging activities should
be developed and implemented.
The Service believes that sand removed from the channel, if of
appropriate size, should be used for beach nourishment of
adjacent beaches rather than removing the material from the
littoral zone. Beach nourishment should occur between December
1 through mid-February so as to avoid impacts to nesting birds
and nesting and hatchling sea turtles and to allow recruitment
of coquina clams and mole crabs during the spring.
Literature cited
American Fisheries Society. 1980. A List of Common and
Scientific Names of Fishes from the United States and
Canada. 4th ed. American Fisheries Society, Washington,
DC. 174 pp.
Banks, R.C., R.W. McDiarmid, and A.L. Gardner. (eds.) 1987.
Checklist of vertebrates of the United States, the U.S.
territories, and Canada. U.S. Fish and Wildlife Service
Resource Publication 166. 79 pp.
Hackney, C.T. and G.F. Yelverton. 1990. Effects of human
activities and sea level rise on wetland ecosystems in the
Cape Fear River Estuary, North Carolina, USA. Pp 55-61 In
D.F. Whigham, R.E. Good, and J. Kvet (eds). Wetland Ecology
and Management: Case Studies. Kluwer Academic Publishers,
the Netherlands.
26

M
•
Linton, T.L., N. Hall, D. Labomascus and A. Landry. 1985. The
Effects of Seismic Sounds on Marine organisms: an Annotated
Bibliography and Literature Review. Texas A & M University,
Galveston, Texas. 67 pp.
Nelson, D.A. and D.D. Dickerson 1988. Response of Nesting Sea
Turtles to Tilling of Compacted Beaches, Jupiter Island,
Florida. U.S. Army Corps of Engineers, Waterway Experiment
Station, Vicksburg, Mississippi.
North Carolina Coastal Resources Commission. 1990. Final
Report of the Maritime Forest Working Group. North Carolina
Department of Environment, Health and Natural Resources,
Division of Coastal Management, Raleigh, N.C. 31 pp. + app.
Parnell, J.F. and M.A. Shields. 1990. Management of North
Carolina's Colonial Waterbirds. National Oceanic and
Atmospheric Administration. UNC Seagrant Publication Number
UNC-SG-90-03. 169 pp.
Radford, A.E., H.A. Ahles, and C.R. Bell. 1968. Manual of the
Vascular Flora of the Carolinas. University of North
Carolina Press, Chapel Hill, North Carolina. 1183 pp.
Schwartz, F.J., P. Perschbacher, M. Mcadams, L. Davidson, K.
Sandoy, C. Simpson, J. Duncan and D. Mason. 1979. An
Ecological Study of Fishes and Invertebrate Macrofauna
V Utilizing the Cape Fear River Estuary, Carolina Beach Inlet
and Adjacent Atlantic Ocean, Summary Report 1973 - 1977.
Institute of Marine Science, University of North Carolina,
Morehead City, North Carolina, 568 pp.
U.S. Minerals Management Service. 1990. Final Environmental
Report on Proposed Exploratory Drilling Offshore North
Carolina. Volume I. Minerals Management Service, Atlantic
OCS Region, Herndon, VA. 669 pp.
U.S. Army Corps of Engineers. 1988. Draft Reconnaisance
Report. Wilmington Harbor Passing Lane. Wilmington
District, Corps of Engineers, Wilmington, NC. 149 pp.
1989a. Reconnaissance Level Study, Wilmington
Harbor -.Turns and Bends. Wilmington District, Corps of
Engineers, Wilmington, NC.
37 pp + app.
27
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M
r
w
1991b. Final Reevaluation Report -
Harbor Ocean Bar Channel Deepening. Wilmington
U.S. Army Corps of Engineers, Wilmington, NC. 23
Wilmington
District,
pp + app.
1991c. Reconnaisance Report on Imrpovement of
Navigation Cape-Fear - Northeast Cape Fear Rivers Wilmington
Harbor, North Carolina. Wilmington District, U.S. Army
Corps of Engineers, Wilmington, N.C. 11 pp + app.
Report.
Office,
_ 1990. Draft Fish and Wildlife
Wilmington Harbor Passing Lane.
Raleigh, NC. 51 pp.
28

. 1989b. Final Environmental Impact Statement for
Long-Term Maintenance of Wilmington Harbor, North Carolina.
Wilmington District, U.S. Army Corps of Engineers,
Wilmington, NC. 100 pp + app.
1990a.
Turns and Bends.
Wilmington, NC. 14
Draft Feasibility Study Wilmington Harbor
Wilmington District, Corps of Engineers,
pp + app.
1990b. Final Supplement to the Final
Environmental Impact Statement. Wilmington Harbor Northeast
Cape Fear River. Wilmington District, Corps of Engineers,
Wilmington, NC. 106 pp + app.
1990c. Wilmington Harbor - Bald Head Island
Evaluation Report. Wilmington District, Corps of Engineers,
Wilmington, NC. 44 pp + app.
1991a. Environmental Assessment and Finding of
No Significant Impact for Maintenance Dredging in Wilmington
Harbor Ocean Bar Channels. Wilmington District, U.S. Army
Corps of Engineers, Wilmington, NC. 8 pp + app.
U.S. Fish and Wildlife Service. 1988a. Planning Aid Report -
Wilmington Harbor Passing Lane. Raleigh Field Office,
Raleigh, NC. 36 pp.
1988b. Final Fish and Wildlife Coordination Act
Report. Wilmington Northeast Cape Fear River. Raleigh Field
Office, Raleigh, NC. 24 pp + app.
1989. Planning Aid Report. Wilmington Harbor
Turns and Bends. Raleigh Field Office, Raleigh, NC. 31 pp.
Coordination Act
Raleigh Field
a

1991. Draft Fish and Wildlife Coordination Act
Report. .Wilmington Harbor Turns and Bends. Raleigh Field
Office, Raleigh, NC. 55 pp.
Van Dolah, R.F. and D.M. Knott. 1984. A Biological Assessment
of Beach and Nearshore Areas along the South Carolina Grand
Strand. Final Report to U. S. Department of the Interior,
Fish and Wildlife Service. Marine Resources Division, South
Carolina Wildlfe and Marine Resources Department,
Charleston, South Carolina, 58 pp.
•
29
a
$rA7Z
ti
State of North Carolina
Department of Environment, Health, and Natural Resources
Division of Environmental Management
512 North Salisbury Street • Raleigh, North Carolina 27604
James G. Martin, Governor A. Preston Howard, Jr., P.E.
William W. Cobey, Jr., Secretary November 16, 1992 Acting Director
Ms. L.K. Mike Gantt
USFWS
P.O. Box 33726
Raleigh, NC 27636-3726
Dear Ms. Gantt:
DEM has reviewed the Service's Planning Aid Report for the Wilmington Harbor
Ocean Bar Channel Deepening Project. DEM requests to be included in.mitigation
plan reviews and approval.
Thank you for the opportunity to review and comment on the report. Should
you have any questions, please contact Mr. Eric Galamb or me at 733-1786.
Sincerely,
r
Jon R. Dorney
Environmental Supervisor
REGIONAL OFFICES
Asheville Fayetteville Mooresville Raleigh Washington Wilmington Winston-Salem
704/251-6208 919/486-1541 7 04/663 -1699 9 19/57 1-4700 919/946-6481 919/395-3900 919/896-7007
Pollution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

f
United States Department of the Interior
FISH AND WILDLIFE SERVICE
Ecological Services
Post Office Box 33726
Raleigh, North Carolina 27636-3726

June 10, 1993
Mr. John Dorney
N.C. Division of Environmental Management
Post Office Box 29535
Raleigh, North Carolina 27626-0535
Dear Mr. Dorney:
TAKES
PRIDE INS
AMERICA
7
Attached is the Service's Draft Fish and Wildlife Coordination
Act Report for the Wilmington Harbor Ocean Bar Channel
Deepening Project, New Hanover County, North Carolina being
conducted by the Wilmington District U.S. Army Corps of
Engineers. This report identifies baseline fish and wildlife
resources in the general study area, discusses potential
impacts to these resources and offers recommendations to the
Corps to use in project plans.
We would appreciate receiving
staff would like to provide by
be incorporated into our Final
Act Report.
any comments which you or your
July 16, 1993 so that they can
Fish and Wildlife Coordination
Technical questions should be directed to the attention of
Karen Warr of this office. She may be reached at 919/856-4520.
Thank you, in advance, for you assistance in the planning of
this project.
Sincerely yours,
Lcir?
L.K. Mike Gantt
Supervisor
w.

U.S. DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
?t
Raleigh Field Office
551 F Pylon Drive
Post Office Box 33726
Raleigh, North Carolina 27636-3726
K,
?)
J
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
DRAFT FISH AND WILDLIFE
COORDINATION ACT REPORT
Prepared by
Karen R. Warr
L.K. Mike Gantt
Supervisor
Released by'
U.S. Fish and Wildlife Service
Raleigh, North Carolina
June 1993

7
?. ,?-
TAKE?
PRIDE IN?
AMERICAS M
l'
United States Department of the Interior
FISH AND WILDLIFE SERVICE
Ecological Services
Post Office Box 33726
Raleigh, North Carolina 27636-3726
June 7, 1993
Colonel Walter S. Tulloch
District. Engineer .
U.S. Army Corps of Engineers
P.O. Box 1890
Wilmington, North Carolina 28401-1890
Dear Colonel Tulloch:
Attached is the Service's Draft Fish and Wildlife Coordination
Act Report (Report) for the Wilmington Harbor Ocean Bar
Channel Deepening Reevaluation Study. This Report identifies
fish and wildlife resources located within the project area
and provides recommendations designed to minimize impacts to
these resources.
The Service is very concerned that blasting will be required
in order to remove rock from underneath the channel. If
blasting is required, it will result in the mortality of an
undetermined number of organisms within the vicinity,
potentially including Federally-listed endangered and
threatened species such as northern right whales, shortnose
sturgeon, West Indian manatees, and loggerhead sea turtles.
We strongly believe that blasting should be avoided if at all
possible. If blasting is required, measures to reduce the
size of the lethal zone and the impacts to fish and wildlife
resources should be implemented.
Although it appears that rock dredged from the channel will be
in pieces too small to be high value reef material, if
blasting occurs, rock of appropriate size for artificial reefs
may result. We support the Corps' preliminary plans to offer
this material to the North Carolina Division of Marine
Fisheries Artificial Reef Program for use in constructing an
artificial reef, provided it is of high quality and free of
contaminants. An artificial reef created with natural rock
would provide substrate for marine organisms to attach and
grow, would provide excellent foraging habitat.and would serve
as a refuge for fish and other organisms.
t
.In our view, the planning for this project is not as advanced
as it usually is at this stage in the process. Specifically,
we do not know if blasting will be required-,,a comprehensive
biological monitoring plan has not been developed, and the
sand budget for the area has not been provided to our office
for planning purposes. In view of this, the Fish and Wildlife
service believes it may be necessary to prepare an updated
Draft Fish and Wildlife Coordination Act Report as planning
proceeds.
We appreciate the opportunity to provide this report, and we
look forward to continued involvement in the planning for this
proposed project.
Sincerely, /
L.K. Mike Gantt
supervisor
r

EXECUTIVE SUMMARY
This Draft Fish and Wildlife Coordination Act Report contains
planning information pursuant to the U.S Fish and Wildlife
Service's responsibilities under the-general authority of the
Fish and Wildlife Coordination Act, as amended (48 Stat.
401;16 U.S.C. 661-667) for the Wilmington Harbor Ocean Bar
deepening project. Project plans call for deepening the
channel to its authorized depth of 40 feet plus 1 foot of
overdepth for areas underlain by rock and 2 feet additional
allowable overdepth to account for dredging inconsistencies.
Thus, in areas where rock is present, the channel will be
deepened to a maximum depth of 43 feet and where rock is not
present the channel will be deepened to a maximum depth of 42
feet. The project is authorized by the River and Harbor and
Flood Control Act of 1962 and is described in Senate Document
No. 114, 87th Congress, 2nd session.
Initial deepening will require the removal of approximately
830,000 cubic yards (cy) of limestone rock and approximately
100,000 cy of sand, silt, clay, and shell fragments over the
amount that is currently removed during maintenance dredging.
It is estimated that less than two percent of the total rock
or less than 14,000 cubic yards may be non-dredgeable and may
require blasting.
i
a
Of utmost concern to the-Service is the potential use of
blasting for removal of rock underneath the channel. Blasting
will result in the mortality of fish and invertebrates
including larvae and potentially of right whales and other
marine mammals, sea turtles, West Indian manatees, and
shortnose sturgeon if they happen to be within a certain
radius of the blasts. Careful time-of-year planning will be_.
necessary if blasting is used, but it will be very difficult
to avoid impacts to all species of concern, including
Federally-listed species, due to different critical time
periods at which the species are potentially utilizing the
channel and surrounding waters. Pre-blasting surveys will be
necessary to determine if West Indian manatees are within the
lethal zone of the blast site and detonation will be postponed
until the area is free of manatees. Monitoring for other
Federally-listed species and marine mammals which may occur
within the project area-may be necessary but the National
Marine Fisheries Service has jurisdiction over those species.
The Service recommends that post- blasting monitoring be
conducted in order to assess the extent of mortality and
injury to fish caused by blasting.
Dredging also will result in mortality, of sessile species and
those unable to escape`-the dredge head. Seasonal
constrictions will be necessary for dredging activities in
order to minimize impacts to finfish and invertebrate larvae.
i i-

Although it appears that rock removed by dredging will not be
of an appropriate size to provide suitable reef habitat, the
Corps has indicated that if blasting occurs, rock removed may
be large enough to be used in artificial reef construction.
We support the Corps' plans to make this rock available to the
North Carolina Division of Marine Fisheries for artificial
reef construction, but the Service recommends any such plan be
closely coordinated with the National Marine Fisheries Service
and the North Carolina Division of Marine Fisheries.
iii
a
J('
TABLE OF CONTENTS
Introduction 1
Purpose, Scope and Authority 1
Coordination with State and Federal Agencies 3
Prior Studies 3
Study Site Description _ 5
Fish and Wildlife Resource Concerns and Planning Objectives 10
Evaluation Methods 12
Existing Fish and Wildlife Resources 12'
Marine and Estuarine Waters 13
Intertidal Oyster Reefs' 18
Intertidal Flats 19
Marsh 19 ........
Forested Wetlands 20
Colonial Waterbird Islands 21
Barrier Island Communities 22
Intertidal Beach 23
Upper Beach and Berm 23
Dunes 24
Maritime Shrub Thicket/Forest 25
Federally-Listed Endangered and Threatened Species 26
Future of Project Area Without the Project 32
Description of Alternatives 36
Description of Impacts 41
Impacts Related to Dredging 41
iv
W
Impacts Related to Blasting 42
Impacts Related to the Deepening of the Channel 47
Impacts Related to Disposal of Material Removed from
Channel 49
Comparison of Alternatives 51
Fish and Wildlife Conservation Measures 52
Recommendations 58
Summary 63
Literature Cited 65
FIGURES
Figure 1: Study Area Showing Wilmington Harbor Ocean Bar
(Baldhead Shoal) Channel, Bald Head Island and
..Oak Island 6
Figure 2: Wilmington Harbor Ocean Bar (Baldhead Shoal)
Channel and Other Channels in the Area 7
v
The Wilmington Harbor Ocean Bar Project involves the deepening
of the Wilmington Harbor Ocean Bar Channel, also called the
Baldhead Shoal'Channel, to its authorized depth of 40 feet
plus 1 foot of overdepth for areas underlain by rock and 2
feet additional allowable overdepth to account for dredging
inconsistencies. Thus, in areas where rock is present, the
channel will be deepened to a maximum depth of 43 feet and
where rock is not present the channel will be deepened to a
maximum depth of 42 feet. The project is authorized by the
River and Harbor and Flood Control Act of 1962 and is
described in Senate Document No. 114, 87th Congress, 2nd
Session.
Between 1968 and 1973, the channel was widened and deepened.
Although the deepening was authorized to 40 feet,
unanticipated rock was encountered preventing deepening past
38.5 feet. An inaccurate tide gage led the U.S. Army Corps of
Engineers (Corps) to believe the channel was actually 40 feet
deep. However, when the tide gage was replaced two years ago,
the actual depth of 38.5 feet has revealed. Due to rapid
shoaling in the area, the current depth of 38.5 feet is
1

available only 50 percent of the year, and approximately 1
foot less is available in the Ocean Bar Channel the remainder
of the year. Vessels require approximately 2 feet more
clearance in the Ocean Bar Channel than in the river channels
due to wave action. The North Carolina State Port Authority
and vessel pilots have requested a deeper bar channel so that
rock.outcroppings can be avoided and the overall efficiency of
navigation through Wilmington Harbor can be improved.
This report is provided in accordance with provisions of the
Fish and Wildlife Coordination Act (48 Stat. 401, as amended;
16 U.S.C. 661-667) and pursuant to the U.S. Fish and Wildlife
Service's (Service) responsibilities under the Scope of Work
Agreement for FY 93. When finalized, this report will
r
constitute the final report of the Secretary of the Interior
as required by Section 2(b) of the Fish and Wildlife
Coordination Act, as amended.
The purpose of this report is to describe the fish and
wildlife resources within the study area, to assess the
potential impacts to fish and wildlife resources, to discuss
fish and wildlife resource problems and conservation
opportunities, and to recommend measures to conserve fish and
wildlife resources.
2

Coordination with
In preparation of
the National Mari
Carolina Wildlife
Carolina Division
Carolina Division
Prior Studies
State and Federal Agencies
this report, the Service coordinated with
ae Fisheries Service (NMFS), the North
Resources Commission (NCWRC), the North
of Marine Fisheries (NCDMF), and the North
of Coastal Management (NCDCM).
Related projects include those Corps studies associated with
other sections of Wilmington Harbor. The Wilmington Harbor
Turns and Bends Project involves the widening of six channel
turns.and bends (U.S. Army Corps of Engineers [hereafter
USACOE] 1989a, USACOE 1990a, U.S. Fish and Wildlife Service
(hereafter USFWS] 1989, and USFWS 1991). The Wilmington
Harbor Passing Lane Project involves the creation of a passing
lane about midway between the mouth of the Cape Fear and the
port of Wilmington (USACOE 1988, USFWS 1988a, and USFWS 1990).
These two projects are now being combined into one project
known as the Wilmington Harbor Channel Widening Study.
The Wilmington Harbor-Northeast Cape Fear River project
involves navigation improvements in the upper reaches of
Wilmington Harbor. The most recent reports regarding this
3
_ r

project are the Final Supplement to the Final Environmental
Impact Statement (USACOE 1990b), the Environmental Assessment
and Finding of No Significant Impact regarding project
modifications and the mitigation plan (USACOE 1993a) and the
Final Fish and Wildlife Coordination Act Report (USFWS 1988b).
The Corps also has prepared a Final Environmental Impact
Statement for Long-Term Maintenance of Wilmington Harbor.,
North Carolina (USACOE 1989b).
To assess further deepening and widening of Wilmington Harbor,
the Corps is conducting a comprehensive study of navigation
improvements. The Wilmington Harbor Comprehensive Study
involves an overall approach to widening and deepening
projects in the harbor along its entire length.from the ocean
Bar Channel to.a point on the Northeast Cape Fear River
approximately 1.7 miles upstream of the Hilton Railroad Bridge
above Wilmington (USACOE 1992). The Comprehensive Study will
assess further deepening of Wilmington Harbor channels
including the Ocean Bar Channel, widening of two turning
basins, and additional modifications to the channel turns and
bends and the passing lane (USACOE 1992).
An Environmental Assessment and Finding of No Significant
Impact for Maintenance Dredging in Wilmington Harbor Ocean Bar
Channels was prepared by the Corps (USACOE 1991a). Bald Head
4
AF
r
v
Island Beach nourishment was discussed in the Wilmington
Harbor-Bald Head Island Evaluation Report (USACOE 1990.c)._
For the current project - Wilmington Harbor Ocean Bar Channel
Deepening, the Corps has provided a Reevaluation Report which
concluded that the improvements are economically feasible and
can be implemented without additional Congressional
authorization (USACOE 1991b). They are currently preparing an
Environmental Assessment for the project.
STUDY SITE DESCRIPTION
The study area is located in southeastern North Carolina off
the coast of Brunswick County (Figure 1). The Wilmington
Harbor Ocean Bar Channel is located at the mouth of the Cape
Fear River. between Bald Head Island to the east and Oak Island
to the west. Bald Head Island is actually part of a three
island complex known as the Smith Island Complex. The town of
Southport is on the mainland landward of the channel to the
northwest.. Wilmington Harbor is divided into several
channels. The outer, seaward portion is called the Baldhead
Shoal or Ocean Bar Channel. Moving upriver toward Southport,
the four adjacent upstream channels are the Smith Island
Channel, Baldhead-Caswell Channel, Southport Channel, and
Battery Channel (Figure 2). At Southport, the channel turns
northward
5

t
TO WILMINGTON
N
FISHER
v?
Q?
P?
v?
O
~J
?-
Q?
V? ?j?
1if 1 \ (`l )
ATLANTIC OCEAN
FIGURE 1 - STUDY AREA SHOWING WILMINGTON HARBOR OCEAN BAR
- (BALDHEAD SHOAL) CHANNEL, BALD HEAD ISLAND AND OAR ISLAND.
?,? BATTERY ISLAND
?-,SOUTHPORT
\«,--BALDHEAD-
y CASWELL
" 0 Island 11
SMITH ISLAND"\ ?
1

3ALDHEAD SHOAL /
/
/
/
/

n
-n
c
?A

? ? ATE
OCEAN
Channel to Be Deepened
'/ - WHIR
4000 2000 0 4000 6000
SCALE IN FEET (1:50. 000)
WILMINGTON HARBOR. NORTH CAROLINA
WILMINGTON HARBOR
BAR CHANNEL
FIGURE-2 -``AILMINGTON HARBOR OCEAN BAR (BALDHEAD SHOAL)
CHANNEL AND OTHER CHANNELS IN THE AREA
Source: U.S. Army Corps of Engineers 1991b.
s.

and extends up to the port of Wilmington, located
approximately 26 river miles upstream from the mouth of the
river.
The Ocean Bar Channel is about 38.5 feet deep below mean low
water (mlw) and 500 feet wide. The channel is approximately
24,000 feet long and oriented in a northeast-southwest
direction. From the upstream limit of the ocean bar channel
to Southport, the authorized depth of 40 feet has been
reached. Between Southport and Wilmington, a 38-foot deep by
400-foot-wide channel is available. Approximately 82 percent
of commerce in Wilmington Harbor results from deepdraft ocean
going trade. Vessels with drafts of over 32 feet cannot
transit the Ocean Bar Channel without waiting for high tide.
Many vessels calling at the Port of Wilmington require light
loading in-order to transit the ocean bar and those drafting
over 36 feet must be light loaded even at high tide (USACOE
1992). The deficiency in the ocean bar limits the use of the
entire Wilmington Harbor project (USACOE 1992). According to
the Corps, even if the ocean bar channel is deepened to its
authorized 40-foot depth, light loading and tidal delays would
still occur for some ships based on projections of future
vessel sizes and historical data (USACOE 1992).
8

r
Salinities around the mouth of the Cape Fear River are
generally greater than 10 parts per thousand (ppt) during
spring, and they increase to about 32 ppt by fall (Schwartz et
al. 1979). Saline water reaches a considerable distance up
the Cape Fear River as a result of dredging activities and sea
level rise. During the past century, drastic changes in
community structure have occurred as saltwater intrusion has
converted freshwater wetlands into salt marsh in the middle
reaches of the estuary and into oligohaline marshes in the
upper reaches of the estuary. The salt marshes of the lower
reaches of the estuary have not changed (Hackney and Yelverton
1990).
The channel is underlain by bedrock. Limestones of either the.., _
Eocene Castle Hayne type or the Cretaceous Peedee Formation
lie at the top of the rock. The precise thickness and extent
of these rock types is unknown under the channel. The
thickness of the rock types and the hardness may vary
considerably along short distances. In some areas the Castle
Hayne limestone may be cemented and in other sections, it may
be softer and easier to break (Bill Hoffman, North Carolina
Geological Survey, personal communication, August, 1992). The
upper layer of the Peedee formation limestone is generally
harder than the Castle Hayne formation (USACOE 1991b). Rock
from both the Castle Hayne limestone and the Peedee formation
9

has required blasting in other portions of the Cape Fear
River.
FISH AND WILDLIFE RESOURCE CONCERNS AND PLANNING OBJECTIVES
The involvement of the Service in this study is in response to
a Congressional mandate through the Fish and Wildlife
Coordination Act which directs that fish and wildlife resource
conservation shall receive full and equal consideration and be
coordinated with other features of Federal projects.
Fish and wildlife resource concerns associated with this
project center primarily around the potential impacts to
marine resources within the vicinity of the proposed project
including important fishery resources, marine mammals, and sea
turtles which may be in the area during deepening activities.
Also of concern are: (1) the potential for the project to
alter the sand budget system and affect littoral transport of
sand adjacent to Bald Head Island and other shorelines in the
area; (2) the potential of the project to result in larger
vessel use of Wilmington Harbor resulting in larger wakes
possibly increasing the erosion of estuarine shorelines,
including colonial waterbird nesting islands; and (3)
potential impacts to freshwater wetlands along the Cape Fear
River near Wilmington resulting from cumulative impacts of
10

deepening the harbor, thus, increasing saltwater intrusion in
the river.
The Service proposes the following planning objectives for the
study:
1._ Conduct harbor deepening activities in the manner least
likely to result in the mortality of marine life. The
alternative of blasting should be viewed as a last resort and
conducted only after demonstrating that rock can not be
removed by dredging or any other environmentally acceptable
.method.
2. Use suitable rock removed from the channel for :creation of
an-artificial reef in coordination with the National. Marine
:Fisheries Service and the North Carolina Division of Marine
Fisheries.
3. Consider using suitable sand dredged from the channel for
nourishment of Bald Head Island, Oak Island, Battery Island,
or dredged disposal islands within the Cape Fear River which
are used by colonially nesting waterbirds.
In accordance with the Fish and Wildlife Coordination Act, as
amended, these planning objectives should be given full and
11
x
equal consideration.with other features of the study area.
The following sections define the existing fish and wildlife
habitat values, assess the potential impacts of the proposed
plan, and provide the Service's recommendations for habitat
conservation and enhancement.
EVALUATION METHODS
Descriptions of natural resources present within the study
area and assessments of anticipated impacts to these resources
are derived from review of published literature, personal
communications with Corps biologists, biologists from other
natural resource agencies, and with recognized authorities on
local fish and.wildlife resources. Nomenclature in this
report follows Radford et al. (1968) for plants; the American
Fisheries Society (1991) for fish; and Banks et.al. (1987) for
birds, reptiles, amphibians, and mammals.
EXISTING FISH AND WILDLIFE RESOURCES
The study area includes marine waters around the ocean bar
channel and estuarine waters further upstream in the Cape Fear
River, as well as terrestrial and wetland communities
associated with nearby barrier islands, dredged material
disposal islands, and the mainland areas bordering the Cape
12
r
Fear River. The following habitats may-potentially be
affected by the project and are discussed in this report:
marine and estuarine waters; estuarine intertidal oyster
reefs; intertidal flats; marsh communities; forested wetlands;
colonial waterbird nesting islands; and barrier island
communities categorized as intertidal beach, upper beach,
dunes, and maritime shrub thicket/forest. Fish and wildlife
resources are discussed for these habitats.
Marine and Estuarine Waters
Trawling surveys conducted as part of a study concerning the
effects on aquatic resources of the Carolina Power and Light
nuclear power plant in Southport demonstrate that the Cape
Fear River and nearby ocean waters are utilized by a diverse
group of invertebrates and fish species (Schwartz et al.
1979). The most abundant invertebrate species were
arthropods, such as the blue crab (Callinectus sapidus), the
lesser blue crab (Callinectus similis), mantis shrimp (Squilla
empusa), penaed shrimp (Penaeus aztecus, P.duorarum, P.
setiferus), and grass shrimp (Palaemonetes sp.); echinoderms,
such as the common sea star (Asterias forbesi) and sand dollar
(Mellita quinquiesperforata); jellyfish (Scyphozoa) and other
cnidarians; comb jellies (Ctneophora); and various mollusks
such as oysters (Crassostrea virginica), Atlantic brief squid
13

(Lolliguncula brevis), conchs and whelks (Melongenidae), and
mud snails (Nassariidae). Many other invertebrate species
were found in smaller numbers.
Common fish species in the Cape Fear River Estuary and
nearshore ocean waters include menhaden_(Brevoortia tyrannus),
spot (Leiostomus xanthurus), grey trout (Cynoscion regalis),
spotted hake (Urophycis regius), Atlantic croaker (Micropogon
undulatus), star drum (Stellifer lanceolatus), anchovies
(Anchoa spp.), summer flounder (Paralicthys dentatus), and
southern flounder (Paralicthys lethostigma). Many of these
are estuarine dependent species, spawning offshore and moving
into the estuarine waters as larvae. The Ocean Bar Channel is
a migration route for these species as they move into the
estuary as larvae and as they migrate back into the ocean as
juveniles or adults.
Anadromous species such as blueback herring (Alosa
aestivalis), alewife (Alosa pseudoharengus), American shad
(Alosa sapidissima), and Atlantic sturgeon (Acipenser
oxyrhynchus) move up rivers into fresh or brackish water to
spawn primarily during January, February, and March. The
shortnose sturgeon (Acipenser brevirostrum), a Federally-
listed endangered species, is an anadromous species which is
known to inhabit the Cape Fear River estuary. Although there
14

are still a lot of unknowns regarding the shortnose sturgeon
population in the Cape Fear River, numbers of the species
within the estuary appear to be very low. Dr. Mary Moser and
Dr. Steve Ross of the University of North Carolina at
Wilmington have been studying sturgeon within the Cape Fear
River for the past few years. During three years, they caught
over 100 Atlantic sturgeon, and only 9 shortnose sturgeon (Dr.
Mary Moser, personal communication, April, 1993). It is
unknown whether or not the Cape Fear River shortnose sturgeon
are making an ocean run or are remaining in the Power estuary
during the summer months. If they are making ocean runs, they
must be migrating through the general ocean bar area.
However, their presence in the ocean bar area has not been
documented. According"to Dr. Moser, sturgeon within the Cape .
Fear River appeared to stick to the main channel and appear to
be attracted to areas with deep holes. Atlantic sturgeon
associate with the deepest parts of the river during the
hottest times of the year.
Marine mammals occur in offshore and inshore waters of North
Carolina. Some species occur farther offshore than project
limits, and others occur in the waters closer to shore. The
sperm whale (Physeter macrocephalus) is a year round resident
of the shelf edge and pelagic waters off North Carolina,
probably moving farther offshore during the winter. The
15

Federally-endangered right whale (Balaena glacialis) and
humpback whale (Megaptera novaeangliae) are spring and fall
migrants off of North Carolina. Both species may be found in
nearshore waters, and the right whale appears to prefer
shallow waters. Although the following species are generally
found in deeper waters, limited beach strandings have been
recorded in North Carolina for these species: dwarf sperm
whale (Kogia simus), pygmy sperm whale (Kogia breviceps),
True's beaked whale (Mesoplodon mirus), killer whale (Orcinus
orca), short-finned pilot whale (Globicephala macrochynchus),
and spinner dolphin (Stenella longirostris) (Webster et al.
1985). Bottle-nosed dolphins (Tursiops truncatus) and harbor
porpoises (Phocoena) utilize nearshore waters including bays,
estuarine creeks, and sounds. They are the most common
cetaceans in the area. Bottlenose dolphins are commonly
observed in the estuarine waters between Bald Head Island and
Southport.
Five sea turtle species inhabit the coastal waters of North
Carolina. The loggerhead sea turtle (Caretta) is the most
common in the coastal area as it regularly nests on North
Carolina beaches. Most sightings of Kemp's ridley sea turtles
(Lepidochelys kempii) off the North Carolina coast have been
within a few miles of shore. During the 1992 nesting season,
a Kemp's ridley sea turtle nested on Long Beach to the south
16
I
of the study site (Therese Conant, Sea Turtle Coordinator,
N.C. Wildlife Resources Commission, personal communication,
July 1992). Green sea turtles (Chelonia mydas) have been
documented to have nested on southern beaches in the past few
years including one record on Bald Head Island. The
hawksbill sea turtle (Eretmochelys.imbricata) is rare north of
Florida, but there have been limited sightings off the North
Carolina coast. The leatherback sea turtle (Demochelys
coriacea) is found between 10 to 30 miles offshore during
April through October and seldomly comes closer into shore
(U.S. Minerals Management Service [hereafter USMMS] 1990).
Kemp's ridley, loggerhead and green sea turtles utilize the
Cape Fear River estuary at times, primarily during the warmer
months. Leatherback sea turtles have been documented within .
Core and Pamlico Sounds and may possibly occur within the Cape
Fear River. Hawksbill sea turtles are extremely rare in North
Carolina, but one was found at the Carolina Power and Light
Plant in Southport several years ago (Sherry Epperly, National
Marine Fisheries Service, Beaufort Laboratory, personal
communication, April, 1993). Between 1990 and 1991, 12 sea
turtles were observed in the Cape Fear River by recreational
fishermen (National Marine Fisheries Service 1993). In more
southern areas it has been documented that sea turtles bury
into inshore sediments during cooler months. However, this
"mudding in" has not been documented in inshore waters of
17

North Carolina and it is unknown whether or not it occurs in
North Carolina.
American alligators (Alligator mississippiensis) are known to
occur in the Cape Fear River and surrounding habitats.
Alligator tracks have been observed on dredge disposal islands
near the project site, and a few.alligators inhabit Bald Head
Island.
The Cape Fear River estuary is utilized by waterfowl with over
12 species observed during the Service's 1988 through 1993
mid-winter waterfowl surveys (Otto Florschutz, U.S. Fish and
Wildlife Service, Migratory Bird Field Coordinator, personal
communication, April, 1993). The most common species observed
include the mallard (Anas platyrhynchos), American black duck
(Anas rubripes), ring-necked duck (Aythya collaris),
bufflehead (Bucephala albeola), mergansers (Mergus sp.), and
green wing teal (Anas crecca).
Intertidal Oyster Reefs
The intertidal estuarine areas in the project vicinity support
extensive oyster reefs in some locations such as around Zekes
Island, north of Bald Head Island. Oyster reefs support a
valuable fishery in the area, and the reefs are inhabited and
18

utilized by many species of invertebrates, fish, and birds.
other intertidal habitats in the area include intertidal flats
and marsh communities.
Intertidal Flats
Intertidal flats support burrowing invertebrates, such as
jacknife clams (Tagelus spp.) and various polychaetes, such as
the plumed worm (Diopatra cuprea). These invertebrates are
prey for fish which forage over the intertidal flats when they
are submerged and for numerous other animals such as American
oystercatchers (Haematopus palliatus), black-bellied plovers
(Pluvialis squatarola), gulls (Lanus sp.), dunlin (Caladris
alpina), western sandpipers (Calidris mauri) and raccoons
(Procyon lotor) when the flats are exposed or when water
levels are low.
Marsh
Marshes are highly productive, essential components of
estuarine and marine food webs. They serve as nursery areas
for many fishery species and are utilized by numerous birds,
and various mammals and reptiles. Marsh communities within
the project site are of two main types: smooth cordgrass
(Spartina alterniflora) marsh and black needlerush (Juncos
19

roemerianus) marsh. Along the margins of the Cape Fear River
near the mouth, the marsh is primarily dominated by smooth
cordgrass. Other species of this community include sea
lavender (Limonium carolinianum), sea oxeye (Borrichia
frutescens), saltwort (Salicornia virginica), and salt meadow
cordgrass (Spartina patens). Farther upstream in the middle
portions of the estuary and within interior portions of Bald
Head and other islands, black needlerush marsh, a brackish
community, is found. These black needlerush marshes have
replaced forested wetlands due to increased tidal amplitude
and saltwater intrusion. Saltwater intrusion has occurred as
a result of dredging activities in the harbor channels and the
creation of Snow's Cut, a channel cut between the Atlantic
Intracoastal Waterway and the Cape Fear River, allowing
.
saltwater from Carolina Beach Inlet to move up the river.
Within the upper reaches of the estuary, oligohaline marsh is
found. Here salinities range from 0 to 5 parts per thousand.
Cattail (Typha spp.), big cordgrass (Spartina cynosuroides),
and wild rice (Zizania aquatica) are a few of the plants.
Dead cypress trees are found within these oligohaline marshes.
Forested Wetlands
Wooded swamps occur in areas above the influence of salt
water. The most abundant trees are bald cypress (Taxodium
20
A
t
distichum), black gum..(Nyssa sylvatica var. biflora), red
maple (Acer rubrum), and Carolina ash (Fraxinus caroliniana).
As saline water reaches farther upstream, wooded swamp
vegetation is dying and being replaced by oligohaline marsh.
The forested wetlands provide important habitat for many bird
species such as prothonotary warblers (Protonotaria citrea),
various woodpeckers, and wood ducks (Aix sponsa).
Colonial Waterbird Islands
The lower.Cape Fear River estuary is one of the most important
colonial waterbird nesting locations in North Carolina.
Battery Island, located to the northwest of Bald Head Island
is a natural estuarine island owned and managed by the
National Audubon Society. The island contains dense maritime
..shrub thicket vegetation which has supported a mixed-species
nesting rookery since at least 1928. It'is used by glossy
ibis (Plegadis falcinellus), white ibis (Eudocimus albus),
cattle egret (Bubulcus ibis), little blue herons (Egretta
caeurlea), and other waders. Battery Island contains two
separate colonies - the north colony and the south colony.
Collectively, they form the largest wading bird nesting
population in North Carolina (Parnell and Shields 1990).
Several dredged material disposal islands along the lower Cape
Fear River are also used as nesting sites by colonial
21
R
waterbirds. North and South Pelican Islands and Ferry Slip
Island are closest to the study site and are used by brown
pelicans (Pelecanus occidentalis), royal terns (Sterna
maxima), and laughing gulls (Larus atricilla). Black skimmers
(Rynchops niger), common terns (Sterna hirundo) and gull-
billed terns (Sterna nilotica) also nest on Ferry Slip Island.
South Pelican Island and Ferry Slip Island support nearly one
half of the States brown pelican breeding population (Parnell
and Shields 1990).
Ferry Slip Island and South Pelican Island have experienced
severe erosion in the past, such that nesting by colonial
waterbirds was diminishing, and a large number of nests laid
were destroyed. In the winter of 1992, the Corps disposed of
material on Ferry Slip and South Pelican Islands, increasing
the nesting value of these islands. It is likely that these
islands will require additional disposal material in future
years (Dr. James Parnell, University of North Carolina at
Wilmington, personal communication, March, 1993).
Barrier Island Communities
Barrier Island communities on Bald Head Island and Oak Island
are discussed in this report because they may potentially be
affected by the project if deepening of the ocean bar channel
22
4
affects the sediment budget of the area and subsequently
affects erosion of these.islands. Habitats discussed include:
intertidal beach, upper beach or berm, sand dunes, and
maritime shrub thicket/forest.
Intertidal Beach
The intertidal beach is inhabited primarily by coquina
clams (Donax variablis and Donax parvulus), mole crabs
(Emerita talpoida), and probably amphipods, such.-As Haustorius
species. Polychaetes and nematodes also may be important
inhabitants (Van Dolah and Knott, 1984).°` These"invertebrate
species are important prey to fish and shorebirds, such as
sanderlings (Calidris alba), black-bellied plovers and Eastern
willets (Catoptrophorus semipalmatus).
Upper Beach or Berm
The upper beach or berm is located between the high tide
line and the dune line and is largely unvegetated. Scattered
clumps of dune building species such as sea rocket (Cakile
edentula) and possibly seabeach amaranth (Amaranthus pumilus),
a Federally-listed threatened species, are found in this area.
These plants serve as building blocks of dunes by trapping
sand. The upper beach is important nesting habitat for
23
I.
loggerhead sea turtles and for shorebirds, such as Eastern
willets and American oystercatchers, and potentially for the
Federally-listed threatened piping plover (Charadrius
melodus).
Dunes
The dune community is vegetated primarily by sea oats
(Uniola paniculata) and broomsedge species (Andropogon sp.)
with scattered beach pea (Strophostyles helvola), pennywort
(Hydrocotyle bonariensis), sandspur (Cenchrus tribuloides),
sea rocket, seaside croton (Croton punctatus), beach spurge
(Euphorbia polygoniflora), evening primrose (Oenothera
humifusa), and seaside elder (Iva imbricata). Sand dunes
provide habitat for red wing blackbirds (Agelaius phoeniceus),
seaside sparrows (Ammodramus maritimus), rice rats (Oryzomys
palustris), raccoons, lizards and snakes and various other
animals. They provide protection to maritime scrub-
shrub/forest habitats and other communities and structures
located landward of them.
24

Maritime Shrub Thicket/Forest
Maritime shrub thicket/forest habitats are vegetated by
salt spray tolerant species such as live oak (Quercus
virginiana), wax myrtle (Myrica cerifera), yaupon (Ilex
vomitoria), Eastern red cedar (Juniperus virginiana), and
catbriar (Smilax species). Closer to the stressful salt and
wind influences, a shrub thicket community exists with dense
shrubs, vines and stunted live oak trees dominating. Farther
from the harsh salt and wind influences, the shrub thicket
grades into a maritime forest. The maritime forest is
generally less stunted and has a higher plant diversity. Less
salt tolerant deciduous trees may occur in the interior
portionsof the maritime forest. only few relict tracts of
maritime forests are left in North Carolina. Bald Head Island
contains an extensive maritime forest supporting the most
northerly natural saw palmetto (Serenoa repens) population
along the east coast. Maritime forests are very important
resting and foraging habitats for migratory birds, and they
are also heavily used by resident species of birds, snakes,
amphibians, mammals and fish where freshwater ponds are found.
Bald Head Island maritime forests have been categorized as
having 11...much higher than average ecological diversity
compared to most remaining maritime forests...," and the
maritime forest community is described as "...one of the best
25

remaining maritime forests for rare species habitat..."
(North Carolina Coastal Resources Commission 1990).
Federally-listed Endangered and Threatened Species
The following Federally-listed endangered (E), threatened (T),
and threatened by similarity of appearance (T[S/A]) species
may be found within the project area or in areas potentially
affected by the project:
loggerhead sea turtle (Caretta caretta) - T
green sea turtle (Chelonia mydad)" - T
Kemp's ridley sea turtle (Lepidochelys kempii) - E
leatherback sea turtle (Dermochelys coriacea) - E
hawksbill sea turtle (Eretmochelys imbricata) - E
shortnose sturgeon (Acipenser brevirostrum) - E
West Indian manatee (Trichechus manatus) - E
piping plover (Charadrius melodus) - T
American alligator (Alligator mississippiensis) - T
Northern right whale (Balaena glacialis) - E
humpback whale (Megaptera novaeanglia) - E
seabeach amaranth (Amaranthus pumilus) - T
The most common sea turtle in the study area is the loggerhead
which nests on ocean beaches adjacent to the project area.
26
f
The ocean beaches at Bald Head Island are the most highly used
beaches for loggerhead nesting in North Carolina. Over 100
nests are recorded each year and as many as 193 nests have
occurred in one year (Dr. William David Webster, University of
North Carolina at Wilmington, personal communication, May,
1992). This species is found within offshore and inshore
coastal waters including sounds between April.through
November.
Another Federally-listed threatened sea turtle, the green sea
turtle, has nested on Bald Head Island, although this was an
isolated occurrence (Kelly Cook, Bald Head Island Nature
Conservancy, June, 1992). On June 17, 1992 a Kemp's ridley
sea turtle, an endangered species, nested on Long Beach, the
southern section of Oak Island, just to the south of the study
site. This positive identification is the first record of the
species nesting in North Carolina. However, two other
descriptions of sea turtles nesting in North Carolina during
the 1992 season fit the description of the Kemp's ridley
turtles (Therese Conant, Sea Turtle Coordinator, N.C. Wildlife
Resources Commission, personal communication, August, 1992).
Loggerhead, Kemp's ridley, green, leatherback and hawksbill
sea turtles may occur within the nearshore waters of the
project area. However, the hawksbill sea turtle is generally
27
b
not seen north of Florida, but limited sightings of this
species off the North Carolina coast have occurred.
Northern right whales and humpback whales may also be found in
the nearshore waters within the boundaries of the project.
Both species are Federally-listed as endangered. The Northern
right whale is in serious danger of extinction within. the
foreseeable future. The population has not increased
significantly in size since commercial harvests ended over 50
years ago (USMMS 1990). Northern right whales migrate off the
coast of North Carolina during spring and fall. Most
nearshore sightings have been between January through May, but
.. they may be present at other times of the year. Generally,
sightings occur very near the shoreline. Humpback whales are
believed to migrate offshore North Carolina during spring
migration, April and May, and fall migration, September
through December. They are generally found in waters between
66 and 240 feet deep, out of the limits of this project (USMMS
1990).
Shortnose sturgeon occur in the Cape Fear River. However,
their presence within the ocean bar channel area is unknown.
Adults may migrate through the area as they move from ocean to
fresh water areas for spawning and as they return to the
ocean, but this has not been documented (Steve Ross,
28
0
University of North Carolina at Wilmington,' Center for Marine
Science Research, personal communication, August, 1992). It
is possible that the Cape Fear River population does not
actually make ocean runs but just migrates from upriver sites
to the lower reaches of the estuary between spawning periods
(Dr. Mary Moser, personal communication, August, 1992). This
is known to occur in some northern populations of sturgeon.
Shortnose sturgeon begin to migrate up the Cape Fear River
during late December, but it is not known whether this
population is returning from the ocean and is thus passing
through the ocean bar channel area or if the population
remains year round in the estuary. The time period during
which channel deepening is least likely to-result in impacts
to the sturgeon is difficult to determine based on the limited ,
data available. According to Dr. Moser, late August through
September would probably be the best time for work assuming
the sturgeon moves from the ocean to the estuary (Dr. Mary
Moser, personal communication, August, 1992).
The NMFS has responsibility for Federally-listed marine and
anadromous species, including sea turtles when "in the water,"
the shortnose sturgeon, and marine mammals, with the exception
of the West Indian manatee. The NMFS should be contacted
regarding any endangered and threatened marine or anadromous
29
.
species which may be affected by the project. Their address
is:
National Marine Fisheries Service
U.S. Department of Commerce
9450 Koger Boulevard
Duval Building _
St. Petersburg, Florida 33702
The West Indian manatee, also known as the Florida manatee, is
a Federally-listed endangered species. Although this species,
principle stronghold in the United States is Florida, it
occasionally makes its way into the coastal waters of North
Carolina (Webster et al. 1985). Generally, manatees remain
along.the coastal waters of the Florida peninsula during the .
winter and disperse more during the summer.months, some moving
• up along the Atlantic Coast to North Carolina. Observations
of manatees from within the Cape Fear River and surrounding
waters are generally reported every year during the summer
months. Numbers of sightings are very low, but they do occur
within the Cape Fear River on a regular basis during warm
months (David Webster, University of North Carolina at
Wilmington, personal communication, May, 1993, and Mary Clark,
North Carolina Museum of Natural History, personal
communication, may, 1993).
30

The piping plover is a Federally-listed threatened species.
This species' decline is attributed to increased development
and recreational activities on beaches. Vehicle and foot
traffic on beaches can directly crush eggs and chicks or
indirectly lower productivity by disrupting territorial
establishment and breeding behavior. Increased development of
beach areas also has resulted in an increase in plover chick
and egg predators, such as gulls and raccoons.
Piping plovers prefer upper edges of overwash areas at inlets
or large open unvegetated beaches for nesting. While there
has been no documentation of piping plovers nesting on Bald
Head Island, suitable piping plover habitat may exist on the
island., Three piping plover nests were observed on Holden
Beach at the western end of Oak Island during the 1992 season,
but none of these nests were successful. Piping plovers have
also used Oak Island during winter and during migration (Tom
Henson, N.C. Wildlife Resources Commission, personal
communication, August, 1992).
Seabeach amaranth, a Federally-listed threatened species, is
an annual plant which grows on barrier islands primarily on
overwash flats on accreting ends. However, it can sometimes
be found on middle portions of islands on upper strands of
noneroding beaches. It is a dune building pioneer species and
31

is usually found high on the beach in front of the foredune.
This plant has been extirpated from 75 percent of its
historical range, and North Carolina is considered seabeach
amaranth's present stronghold (Weakley and Bucher 1992).
Candidate species are those which, although not now listed-or
officially proposed for listing as endangered or threatened,
are under status review by the Service. These "Candidate" (Cl
and C2) species are not legally protected under the Act and
are not subject to any of its provisions, including Section 7,
until they are formally proposed or listed as threatened or
endangered. These species may be listed in the future at
which time they will be protected by the Act. In the
meantime, we would appreciate anything you might do for them.
The only candidate species which may occur within areas
covered by this project is dune blue curls (Trichostema
dichotomum). Dune blue curls utilizes high dunes and
grasslands behind primary dunes.
FUTURE OF PROJECT AREA WITHOUT THE PROJECT
It is necessary to distinguish between changes in the fish and
wildlife resources which will likely occur without the project
and those expected as a result of the project. To accomplish
32
0
this, a discussion of anticipated future conditions of fish
and wildlife resources without the. project, is presented.
Periodic maintenance of the Ocean Bar channel and other
channels of Wilmington Harbor will continue to temporarily and
periodically increase turbidity in.the waters, resulting in
physiological stress and mortality to some aquatic species,
and will continue to periodically disturb the benthos of
channel bottoms. However, some large shipping lines may
discontinue their use of Wilmington Harbor if the ocean bar
channel is not deepened. If this happens, there will be a
reduction in the number of ships producing large wakes in the
Cape Fear River and possibly a reduction in shoreline erosion
along the river including shorelines of colonial waterbird
nesting islands. If ship use of Wilmington Harbor reduces
drastically, then the frequency of maintenance dredging of
portions of the Harbor may be reduced, and turbidity and
physiological stress to aquatic organisms in the River
resulting from dredging will occur less often.
Further deepening of Wilmington Harbor channels from the ocean
bar to a point on the Northeast Cape Fear River approximately
1.7 miles upstream of the Hilton Railroad Bridge above
Wilmington is being considered in the Wilmington Harbor Cape
Fear - Northeast Cape Fear Rivers Comprehensive Study (USACOE
33

1992). The Comprehensive Study will investigate deepening of
the ocean bar channel beyond that proposed in the current
project. Thus, it is possible that even if the current
project is not carried out, the ocean bar channel may be
deepened as a part of the Comprehensive Study. If the ocean
bar is not deepened as part of the Comprehensive Study, then
deepening of other channels will not be necessary since the
ocean bar channel is the most seaward channel and serves as
the entrance to the Harbor.
Development and alteration of terrestrial and wetland
communities on mainland and barrier islands in the area is
occurring and is expected to continue. Golf courses on Bald
Head Island will continue to be managed and landscaped and as
a result of these activities, nonpoint source runoff may
result in further declines in water quality of adjacent
waters. The study area is expected to remain high value
habitat for estuarine dependent fishery species which will
continue to use local waters for feeding, spawning, and as
nursery habitat. Marine mammals and sea turtles are expected
to continue to use the study waters. Colonial nesting
waterbird islands in the area will continue to support nesting
bird populations as long as management of the islands
continues, including disposal of dredged material when needed.
34

Past Wilmington Harbor Channel construction activities and the
creation of Snows Cut connecting the Atlantic Intracoastal
Waterway with the Cape Fear River, along with continued sea
level rise, have resulted in increased tidal amplitudes and
saltwater intrusion up the Cape Fear River. The estuary's
freshwater wooded swamps are being converted into salt,
brackish.and oligohaline tidal marshes. Dredging activities
within the Cape Fear River, such as the widening of a turning
basin and the construction of a passing lane, will likely
result in further intrusion of saltwater into the upper
reaches of Wilmington Harbor.
Beach nourishment occurred on Bald Head Island during 1991,
and this activity may continue annually or less frequently in ..
the future. A 50-year plan for annual beach nourishment has
been prepared by the Corps. However, annual approval will be
required. Beach erosion is serious on Bald Head Island and
with sea level rising, with the continued use of the
Wilmington Harbor channels by large ships, and with
maintenance dredging of the Wilmington Harbor channels
occurring, erosion is expected to continue and to increase in
the future. Sea turtle habitat and potential piping plover
habitat may be reduced as a result. Although certain areas
of Bald Head Island may experience severe erosion, the island
35
4
is expected to remain very important nesting habitat for the
loggerhead sea turtle.
DESCRIPTION OF ALTERNATIVES
The proposed project involves deepening the channel so that a
40-foot depth is maintained throughout the year along the
entire channel. The 1991 Reevaluation Report (USACOE 1991b)
presented several alternatives which varied in the amount of
required overdepth. At that time, the Corps believed that a
considerable amount of overdepth would be required in order to
limit maintenance dredging to once a year due to rapid
shoaling of the channel. Alternatives considered for the
. amount of required overdepth were four, three and two feet. -
However, after further analysis, the Corps believes that
maintenance dredging will be necessary only once a year if the
project involves one foot of required overdepth for areas
underlain by rock. Thus, other overdepth alternatives are no
longer being evaluated (John Meshaw, Biologist, Wilmington
District Corps, personal communication, April, 1993).
The following information is taken from an outline of the
project description received from the Corps in April 1993
(USACOE 1993a). The project involves lengthening the channel
from 24,000 feet to 30,500 feet and deepening the entire
36

channel to 40 feet plus 1 foot required overdepth in areas
with underlying rock plus an additional 2 feet of allowable
overdepth to allow for dredging inconsistencies. This means
the actual depth of the channel would be between 42 to 43
feet. The plan would involve an extension of the channel into
the Atlantic Ocean to a point where natural depths are equal
to the channel depth.. The total bottom width of the channel
would not change from 500 feet, and the side slope of the
channel would remain 1 vertical to 5 horizontal (1:5) in areas
of unconsolidated soft material. Side slopes in rock areas
would be steeper (approximately 1:3) in order to limit the
amount of rock requiring removal. The-proposed deepening and
lengthening of the ocean bar channel would increase the
footprint of the channel from 306 acres to 393 acres, a
difference of 87 acres.
Initial deepening will require the removal of approximately
830,000 cubic yards (cy) of limestone rock and approximately
100,000 cy of sand, silt, clay, and shell fragments over that
removed during maintenance dredging. The sand would be
removed by hydraulic pipeline dredge, and the rock would be
removed with a rock cutterhead on a hydraulic pipeline dredge
and/or will require blasting. A scow may be used to carry the
material removed with a pipeline dredge to its destination.
If blasting is necessary, a bucket and barge dredging system
37

will remove the rock after blasting and dispose of the
material.
According to a project descriptions received from the Corps on
April 22, 1993, and May 20, 1993, blasting will be limited to
rock which could not be dredged. It is-estimated that less
than two percent of the total rock or less than 14,000 cubic
yards is non-dredgeable. If blasting is required, numerous
blast holes will be drilled per day, and explosives will be
placed in the holes with crushed stone or other material
filling the hole to the top. This procedure is known as
"stemming the blast." This procedure should reduce the impact
to the surrounding aquatic environment while increasing the
fragmentation of the rock (USACOE 1993b, and 1993c).
During one day, several rows of holes would be drilled and
filled with explosives and 25 millisecond delays would be
incorporated between rows. Using delays reduces each
detonation into several smaller explosions, and the resulting
pressure is related to the size of the charge in each row of
holes rather than the cumulative charge in all holes. This
should reduce the lethal range compared to that which would
result if the charges in each hole were connected (John
Meshaw, Biologist, Wilmington District Corps, personal
communication, April, 1993).
38
The Corps has estimated that to blast the 14,000 cubic yards
of rock, a maximum of 60 blasts would be required. This
estimation is based on the assumption that the maximum number
of holes per day will be drilled and one blast would occur for
all of the holes. The channel deepening would be contracted
out, and certain aspects of any blasting, such as the type of
explosives used, would be the decision of the contractor.
However, water gel explosives are typically used in this type
of work. According to the Corps, the contract which goes out
for bid would state that limited blasting would be allowed and
if blasting occurs, stemming of at least the top foot of the
blast hole would be required, instantaneous delays would be
used between rows, and a limited number of blasts would be
allowed.
The contract would be for the overall deepening of the ocean
bar channel and because blasting is generally much more
expensive than dredging, the contractor would probably benefit
economically by dredging as much of the rock as is possible,
keeping blasting to a minimum. Thus, in theory, the
contractor should dredge rather than blast, if possible (John
Meshaw, Biologist, Wilmington District Corps, personal
communication, May, 1993). Rock is encountered beginning
about 12,500 feet seaward of the entrance to the Cape Fear
River. Therefore, blasting would only potentially be
39

necessary in the area 2 or more miles from the shoreline (John
Meshaw, personal communication, April 1993).
The majority of the material removed will be dumped at the
Wilmington Harbor Ocean Dredged Material Disposal Site (ODMDS)
located about four miles east of the channel. The material
will be placed at the eastern section of the ODMDS, as far
away from the navigation channel as possible (USACOE 1993c).
Some of the rock may be used to create artificial reef
habitat. The NCDMF Artificial Reef Program and the National
Marine Fisheries Service were consulted regarding the
possibility of using rock removed from the channel for
creation of an artificial reef. However, an experimental
removal of some of the rock during 1992 witha cutterhead
pipeline dredge, revealed that the predominant size of the
rock removed by a cutterhead dredge was about the size of golf
balls. Concern was expressed by resource agencies that the
rock removed from the channel may be too small to stack up
properly and provide adequate interstitial spaces needed for a
successful reef. In addition, the rock would have been mixed
with overlying sediments making it even less suitable.
Therefore, rock removed by cutterhead pipeline dredge will not
be used as artificial reef material. Blasting, however,
fractures rock and should produce larger pieces of material
than will dredging. If blasting occurs, approximately 14,000
40

cubic yards of rock may be produced and if it is of .
appropriate size, it may be used for artificial reef creation
(John Meshaw, Biologist, Wilmington District corps, personal
communication, may, 1993). Reef sites which are part of the
NCDMF Artificial Reef Program would be used. The NCDMF is
considering the Reef Sites AR-445,.located approximately 9.8
miles southwest of the entrance channel buoy, or AR-420,-
located about 2:9 miles northwest of the entrance channel buoy
(USACOE 1993c).
Project maintenance would involve annual dredging increases of
approximately 128,000 cy of sand over the amount presently
dredged during maintenance activities (USACOE 1993b).
According to the Corps' project description, project
construction would occur between July 1994 and May 1995.
Drilling and blasting may occur within the last 90 days of
this time period, or approximately March through May, 1995
(USACOE 1993b).
DESCRIPTION OF IMPACTS
Impacts Related to Dredging
The Wilmington Harbor Ocean Bar channel deepening will result
in the disturbance of a 6,500 foot by 500 foot section or
41
y .,

about 75 acres of previously undisturbed ocean bottom.
Approximately 930,000 cubic yards of additional material will
be excavated during the deepening project. Of this,
approximately 830,000 cubic yards is rock and about 100,300
cubic yards is comprised of sand, silt, clay and a small
amount of shell. Removal of rock using.a cutterhead dredge
will result in mortality of benthos, plankton, and nekton
unable to escape the dredge. Larvae are particularly
vulnerable because many are flowing freely with the currents
and are likely to be sucked up by the dredge. Although some
adults would also be swept up by the dredge, most should be
able to avoid it. The most critical time period for larval
fish moving through the estuary is between January through
April.
Impacts Related to Blasting
Blasting will result in the mortality of fish, marine mammals
and sea turtles and other life within a certain radius of the
explosion. The lethal range will depend on the type of
explosives used and the methods of blasting. These have not
been identified by the Corps at this time.
Linton et al. (1985) summarize past studies on the effects of
blasting on marine organisms. Past studies indicate that
42

different species and different life stages react differently
to shock pressures. Eggs, larvae, juveniles, and adult
organisms with air bladders tend to be most susceptible to
explosives. Damage is directly proportional to the pressure
produced by the explosion and the time over which it is
produced. For example, a high velocity explosion produces"'
high pressure over a short duration. The rapid rise and fall
in pressure causes swim bladders to rupture because they do
not have time to adjust. Linton et
generally, high velocity explosions
of 40 pounds per square inch will k
certain radius of the explosion and
pressure above 70 psi will kill all
radius of the blast site. However,
al. (1985) state that
producing a peak pressure
ill some fish within a
those producing a peak
fish within a certain
with low velocity
explosives, such as black powder, pressure rises and falls
slower and fish may withstand pressures over 70 psi.
Linton et al. (1985) cite a study by Fitch and Young (1948)
who found that species with thick-walled swim bladders appear
to be more resilient to 10 to 160 pounds of high explosives
than those with thin-walled swim bladders.
Linton et al.'s (1985) survey of the past literature also
revealed that the effects that water depth, burying charges in
sediment, and methods used to move fish and other organisms
43

away from blasts sites, have on the lethal range and organism
mortality are variable. Some studies indicate that explosives
at greater depths increase the potential to kill fish, but,
other studies show no relationship between water depth and the
lethal potential. It is generally thought that embedding
shots reduces the potential to kill fish. However, some
studies have shown that embedded shots are just as lethal as
others. Hubbs and Rechnitzer (1952) report that charges
killed fish even when explosives were buried by many feet in
sediments. Rasmussen (1967) found that burying charges in the
seabed generally reduced their lethal effect. The extent of
the lethal range may also vary with different ocean floor
configurations. Methods used to drive away organisms from
areas to be exploded have also shown varying results. Based
r
on their literature review, Linton et al. (1985) state that
warning shots are probably not very successful in dispersing
fish away from blast sites. However, as part of a tunnel
construction project in Boston Harbor, sound was used to drive
fish away from blast sites with considerable success (EA
Engineering, Science and Technology et al. 1992).
Coker and Hollis (1950) (cited by Linton et al. 1985) found
that for blasts using high explosives with charges ranging
from 250 to 1,200 pounds, the lethal range did not exceed 600
44
.
feet and was on average approximately 300 feet out from the
blast site.
For various weights of high velocity explosives, Linton et al.
(1985) recommend a minimum distance away from any reefs,
schools of fish and other important aquatic resources of
approximately 1000 feet.
Blasting may result in the mortality of northern right whales,
short-nosed sturgeon, and sea turtles as well as anadromous
fish and larvae of estuarine dependent species. It will be
very difficult to assess the species and the number of
organisms lost as a result of blasting.
Blasting and dredging also will likely result in increased
turbidities in the immediate vicinity, potentially clogging
the gills of fish and invertebrates. Turbidity levels will
depend on the amount of fine materials being resuspended.
Potential impacts to migrating whales, sea turtles, fish, and
invertebrates, especially larvae, can be minimized if
deepening activities occur during periods when these organisms
are not utilizing the study area habitat or when their numbers
are low. Blasting will especially require seasonal
restrictions due to the inability of organisms to escape
45
y
11
blasting effects. Finding a suitable time period for blasting
will be difficult because the critical time periods for
whales, sea turtles, larval fish and anadromous species
differ. The most critical time period for estuarine dependent
larvae passing through the area as they move into the estuary
is between January and April. Whales may be present during
spring migration,'and fall migration. They have been observed
most often during March and April. One October sighting
indicates that they may migrate farther offshore during the
fall. Sea turtles are generally found in the nearshore and
inshore waters between April through November. Shortnose
sturgeon from the Cape Fear River may pass through the ocean
bar area during migration. However, it is unknown whether or
not that population of shortnose sturgeon makes an ocean run
and thus passes through the ocean bar channel. Assuming that
shortnose sturgeon do use the ocean bar area, the period least
likely to impact this fish is probably between mid-August
through September (Mary Moser, University of North Carolina at
Wilmington, Center for Marine Science Research, personal
communication, April, 1993). As mentioned earlier, the
National Marine Fisheries Service is responsible for
Federally-listed endangered and threatened marine and
anadromous species. Monitoring of the area being blasted will
be necessary before and after blasting activities.
46

Impacts Related to the Deepening of the Channel
Deepening the ocean bar channel may increase the tidal
amplitude moving into the Cape Fear River and increase
saltwater intrusion farther upstream. This may result in the
additional conversion of forested wetlands into oligohaline
marsh and more saline environments. Such impacts are
difficult to attribute to particular harbor activities, and
the extent of such habitat conversions is especially difficult
to predict. Habitat conversion of forested wetlands into
oligohaline and salt marsh will benefit fauna adapted to marsh
and adversely affect species depending on forested wetlands,
such as black bear (Ursus americanus), wood duck and songbirds
like the prothonotary warbler. Further saltwater intrusion
will increase the ranges of marine fish and invertebrates,
such as pink shrimp, farther upstream and prevent the movement
of freshwater species downstream.
Deepening of the ocean bar channel also may result in
additional erosion problems to adjacent barrier islands. Deep
channels trap sediments moving through littoral transport
along the coast, and the result may be a starvation of sands
to adjacent beaches, especially if the material removed from
the channel during initial and maintenance dredging is
deposited outside of the littoral system. These impacts also
47
10
are very difficult to predict, especially without a detailed
understanding of the sediment budget in the immediate area.
Bald Head Island has been experiencing serious erosion
especially along its southern beach for two decades. As
requested by the village of Bald Head Island, the Corps
completed a Reconnaissance Report in 1989 on Bald Head Island
which determined that there was no direct relationship between
the dredging of the Wilmington Harbor ocean bar channel and
the severe erosion occurring on Bald Head Island. However,
dredging of navigation channels with offshore disposal has
been linked to erosion of adjacent shorelines. The removal of
material from Oregon Inlet with deposition offshore has been
directly linked to the erosion of adjacent Pea Island. For
every cubic yard of sediment dredged from Oregon Inlet and
removed from the littoral system, an equal amount of erosion
occurs on adjacent beaches (Inman et al. 1989).
The Corps' Wilmington Harbor - Bald Head Island Evaluation
Report, dated June 1990, investigated the possibility of
placing material dredged from maintenance dredging of
Wilmington Harbor channels on Bald Head Island as an erosion
control method. This report determined that the village of
Bald Head Island is eligible for a 50-50 cost sharing for the
added cost of placing compatible material on the beach of Bald
48

Head rather than placing it at the ODMDS several miles
offshore.
Impacts Related to Disposal of Material Removed from the
Channel
A potential positive use of the rock after removal from the
channel would be to use it for creation of artificial reef
habitat, if the rock is of suitable size to stack, if fine
materials are not dumped with the rock, and if the rock is not
contaminated (Steve Murphy, North Carolina Division of Marine
Fisheries, Artificial Reef Coordinator, personal
communication, August, 1992). If silt is deposited along with
the rock and the rock is contaminated, then placing the
material at an existing artificial reef site could result in
adverse impacts to fish already utilizing the reef.
Conversely, if of acceptable quality, it could provide
productive fishery habitat. As indicated earlier, only rock
removed by blasting would potentially be used for artificial
reef creation since rock removed by dredge will probably be
unsuitable.
If material is placed at the Wilmington Harbor ODMDS, benthos
will be_buried and turbidity may temporarily increase, but
because the area is already disturbed, impacts would be
49

r minimal. If rock is placed at the ODMDS, then the disposal
site may reach its capacity more quickly requiring a new site
for future dredged material disposal.
A potential beneficial use of sand removed from the channel
would be beach nourishment of adjacent barrier island beaches,
Bald Head Island or Oak Island, provided the sand is
compatible. Disposal of the material at the ODMDS would
remove material from the littoral system and may accelerate
erosion on Bald Head Island or Oak Island. Material from
maintenance dredging of the channel has been deposited at the
ODMDS in the past, and this activity may have affected the
shoreline along Bald Head Island. Further deepening of the
channel may exacerbate erosion on the island because
additional sand may become trapped in the deeper channel and
removed from the littoral zone as it is dumped at the ODMDS.
Use of sandy material for beach nourishment of Bald Head
Island or Oak Island would keep material within the littoral
zone. Beach nourishment projects are becoming increasing
popular in North Carolina communities and the identification
of suitable borrow material is becoming a major problem. When
possible, compatible material from inlets should be used for
this purpose. However, the Corps has indicated the material
which will be removed from the channel does not contain a
50

sufficient amount of beach quality sand to make beach
nourishment a viable alternative.
COMPARISON OF ALTERNATIVES
Removal of the rock underlying the channel by blasting with
explosives would result in more severe adverse impacts to fish
and wildlife resources than would the use of a cutterhead
dredge. Blasting would kill all organisms within a certain
radius of the explosions, and the extent of blasting-caused
mortality would be difficult to quantify. Blasting could
potentially kill whales, sea turtles, adult fish and
invertebrates, as well as-juveniles and larvae. Mortality
caused by the use of a cutterhead dredge would-be more
localized, and most adult organisms would be able to escape
the dredge. Both processes would result in turbidity plumes,
depending on the amount of fine materials being resuspended.
Possible rock disposal alternatives being considered are the
use of some of the rock for creation of artificial reef
habitat and the dumping of the rock at the Wilmington Harbor
ODMDS. Utilizing rock from the channel as artificial reef
habitat would enhance fishery resources if the rock is of
suitable size to stack, is not contaminated and if silts are
not deposited with the rock. Only rock removed by blasting is
51

expected to be of appropriate size for reef construction.
Artificial reefs provide substrate for marine organisms to
attach and grow, provide excellent foraging habitat, and
become refuges for fish and other organisms. Dumping the rock
at the ODMDS might create hard bottom at the site, but this
would not be a suitable reef location due to future dumping of
dredged material at the site. The ODMDS also may contain
higher levels of pollutants than other areas, making the ODMDS
less suitable as a place for fish to congregate.
FISH AND WILDLIFE CONSERVATION MEASURES
Fish and wildlife conservation measures include: 1)
mitigation; and 2) enhancement. Mitigation, as defined by the
Council of Environmental Quality and adopted by the Service in
its Mitigation Policy (Federal Register 46[15] 1656-1662,
January 23, 1981) includes: 1) avoiding the impact altogether
by not taking a certain action or parts of an action; 2)
minimizing impacts by limiting the degree or magnitude of the
action and its implementation; 3) rectifying the impact by
repairing, rehabilitating, or restoring the affected
environment; 4) reducing or eliminating the impact over time
by preservation and maintenance operations during the life of
the project; and 5) compensating for the impact by replacing
or providing substitute resources or environments. This five-
52
R
action sequence should be viewed as the proper order for
formulating mitigation measures.
If a cutterhead dredge can be used to cut through the rock.
underlying the channel, then many of the major potential
impacts to fish and wildlife resources can be avoided and
minimized. The Service believes the project should be
conducted without the use of blasting if at all possible.
Blasting should be used only as a last resort. If blasting
must occur, then a strict time frame should be developed which
takes into account the presence of endangered and threatened
species such as sea turtles, right whales and shortnose
sturgeon. The use of the channel by anadromous species and
estuarine dependent species also should be considered in
developing the blasting window. Considering the time periods
at which shortnose sturgeon, sea turtles, northern right
whales, anadromous species and estuarine dependent fish and
invertebrate larvae utilize the study area, there is really no
suitable time period for conducting blasting activities. At
all times of the year, blasting may potentially affect one or
another species of concern. The National Marine Fisheries
Service should be contacted regarding Federally-listed marine
and anadromous species.
53

r It may be possible to use blasting during critical time
periods if other measures are undertaken which will ensure
that mortality of endangered and threatened species is
prevented and mortality of other species is minimized. For
example, in Florida, when blasting activities have occurred,
the Service has required that a manatee watch be conducted
with at least two qualified people observing from watercraft,
aircraft or a high vantage point for at least one half-hour
immediately before and after detonation in a defined circular
radius around the blast zone. The defined circular radius is
based on the weight of the explosive charge in pounds. The
following is the formula used in Florida for determining the
lethal zone for manatees:
where
r = 260 3,/W
r = radius of the danger zone in feet
w weight of the explosive charge in pounds (tetryl or
TNT)
Blasting activities implementing this procedure have not
resulted in injury to or mortality of manatees (Don Palmer,
Biologist, U.S. Fish and Wildlife Service, Jacksonville Field
office, personal communication, April, 1993).
54
.
Blasting operations associated with construction of a tunnel
in Boston Harbor involved the use of hydroacoustic resonance
to evaluate the distribution of migrating anadromous fish
relative to the areas where blasting occurred. Plans included
mounting side-scanning transducers on the drill barge and on a
boat working at the edge of the blast zone to monitor schools
of river herring within an approximate 500-foot radius of the
blast site. Periodic net sampling using trawls and gill nets
was used to document the species composition of the
populations detected with the hydroacoustic equipment. Plans
also called for visual monitoring by scientists on a boat, as
well as a mid-water trawl immediately following blasting
events to look for disoriented, injured or dead fish and to
collect and identify any dead or injured fish. Project plans _
for the Boston Harbor blasting project also called for the use
of sound to disperse fish away from the blast zone (EA
Engineering, Science and Technology et al. 1992). As a result
of 30 blasts conducted between May 11, 1992 and May 31, 1992
which incorporated the fish deterrence protocol, only 9
dead/stunned river herring were recovered. Terns and gulls
were observed in the blast zone picking up small fish on
several days, but numbers of dead/injured fish appeared to be
very low (EA Engineering, Science and Technology 1992). The
Corps has contacted the Project Manager of Sonalysts. Inc. and
he indicated that the sound deterrence methodology has been
55

developed and has shown considerable success in other
projects; however, the methodology involves using particular
sound emissions at specific frequencies for specific fish.
Currently the details have been worked out for only a few
species - shad, herring and alewives (John Meshaw, Biologist,
Wilmington District Corps, personal communication, May 1993).
Dredging within the channel using a hydraulic cutterhead
pipeline dredge also should involve a dredging window which
takes into account potential impacts to larvae of estuarine
dependent species. If work is avoided during environmentally
sensitive periods of the year, then direct impacts to fish and
wildlife can be avoided or minimized. Larval fish and
invertebrates are most vulnerable to dredging because many
simply move with the currents while adults can swim out of the
dredge path. The most critical time period for larval fish
moving through the estuary is between January through April,
and dredging with a cutterhead pipeline dredge should be
avoided during this time, if possible (Fritz Rhode, N.C.
Division of Marine Fisheries, Wilmington, NC, personal
communication, August, 1992).
Artificial reef creation would enhance fishery resources and
should be used to partially compensate for unavoidable impacts
to marine resources if suitable rock is produced. As
56
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indicated earlier, only rock removed by blasting is likely to
be suitable reef material.
The saltwater intrusion and habitat conversion which has
occurred and will occur up the Cape Fear River is
attributable, at least partially, to cumulative impacts of
past dredging activities in Wilmington Harbor. The Service
has identified the affected forested wetlands in the area as
Resource Category 2 wetlands and believes the expected future
loss of forested wetlands should involve in-kind habitat
replacement. To do this, the Corps should estimate the
potential losses and replace lost habitat value through
construction of replacement habitats, restoration of
previously altered forested wetlands within the impact areas
to ensure that no net loss of in-kind habitat value occurs.
The Corps should in coordination with the North Carolina
Wildlife Resources Commission, the North Carolina Division of
Coastal Management and the Service, develop and implement a
mitigation plan in response to cumulative salt
intrusion/habitat conversion impacts resulting from past and
present Wilmington Harbor projects.
The potential for the deepening of the channel to accelerate
erosion of nearby beaches may be reduced if sand dredged from
the channel is used for beach nourishment rather than
disposing of the material at the ODMDS outside of the littoral
zone.
57
I
.
RECOMMENDATIONS
The Service believes the following recommendations are necessary
and should be incorporated into project plans to minimize the
expected adverse impacts to fish and wildlife resources.
1. The channel deepening contract should state clearly that
blasting should only be used as a last resort after it is shown
and documented that the rock cannot be removed with a cutterhead
dredge. The Corps has stated that they cannot require the
contractor to complete the deepening project without the use of
blasting, even if blasting is not absolutely necessary; however,
the Corps' experimental rock removal has demonstrated that the
rock can probably be removed through dredging. Therefore to
minimize unnecessary adverse impacts to public trust resources,
the Service prefers and recommends that the project be done by
dredging; however we would consider the use of minimal amounts of
blasting if removal of material with a rock cutterhead dredge is
demonstrated not to be physically possible. In the latter case,
specific additional mitigation measures would be necessary as
addressed in recommendations 2,4,5,6,7,and 8.
2. If blasting is necessary, measures should be implemented to
minimize the lethal range of the blasts. Those measures should
include: drilling holes for the blasts; stemming the blasts; using
as low velocity explosives as is possible without diminishing
58
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effectiveness; using instantaneous delays between rows of blasts;
and keeping the number of blasts per day and the total number of
blasts to a minimum. The Corps' draft description of project
plans stated that these measures will be included in the contract,
and we support efforts in this regard.
3. Careful time-of-year planning and impact preventative measures
are necessary for deepening activities so as to avoid or minimize
impacts to sea turtles, migratory whales, West Indian manatees,
shortnose sturgeon and other anadromous species and estuarine
dependent larvae. Dredging and blasting time frames should be
developed in coordination with the Service, the North Carolina
Division of Marine Fisheries and the National Marine Fisheries
Service and.will be specified in the final report. The best time
for blasting with regard to estuarine dependent larvae and
anadromous species may be the period November 1 through December
15. The National Marine Fisheries Service should be contacted
regarding the best time to conduct activities in order to avoid
impacts to sea turtles, marine mammals, and shortnose sturgeon.
In order to avoid impacts to the West Indian manatee, blasting
activities should be avoided between May through October.
4. The Corps should determine the expected lethal radius out from
the detonation site for all groups of organisms of concern, and
this information should be used to ensure that blasting is avoided
when large schools of fish are within the lethal range of the

V
59
4
blast site or when endangered or threatened species are within the
lethal range of the blast site. The lethal range will likely vary
based on the type of explosive used and the measures implemented
and will vary for different species. The Corps should consider
requiring the contractor to use low velocity explosives because
pressure increases are not as rapid as they are when high velocity
explosives are used, and fish are more likely to survive
explosions.
5. If blasting occurs between May through October, surveys should
be made by at least two Service-approved and qualified observers
from aircraft or watercraft, immediately prior to blasting, to
ensure that no West Indian manatees are within the lethal range of
the detonation. If a manatee is present within the lethal range,
blasting should be postponed until the animal moves by its own
will out of the impact zone. Similar monitoring will probably be
necessary for sea turtles, whales and dolphins. However, the
National Marine Fisheries service has jurisdiction over these
species and the shortnose sturgeon, and that agency should be
contacted regarding protection of these species.
6. Immediately prior to blasting, the impact zone should be
surveyed by qualified observers aboard a boat equipped with fish
finder echolocators or transducers. If large schools of fish are
located within the lethal range of the blast site, blasting
60

V
activities should be avoided until the fish move out of the lethal
range.
7. The Corps should analyze the possibility of using sound as a
fish deterrence in order to disperse fish away from the blasting
zone, should blasting be necessary. This method developed by
Sonalysts, Incorporated, has been successful in deterring alewives
away from blasts during blasting activities related to tunnel
construction in Boston Harbor.
8. A comprehensive post-blasting monitoring plan should be
developed and implemented so that the species and number of
organisms killed by the blasts can be estimated. The monitoring
plan should be developed in coordination with the Service, the
North Carolina Division of Marine Fisheries, and the National
Marine Fisheries Service and should involve surveying the blasting
impact area by boat and counting and identifying dead or wounded
organisms which float to the surface. Although all dead organisms
may not float to the surface immediately, this method should give
an indication of the extent of the impacts to finfish and other
organisms. Other monitoring methods may also be necessary.
9. Although it has been determined that rock dredged from the
channel will likely be too small to be high value artificial reef
material, rock removed by blasting may be of adequate size to
,provide suitable reef habitat. Any material of appropriate size
61
V

Is
should be tested to ensure it is free of contaminants and if
acceptable quality, should be used as artificial reef material.
Such an effort should be closely coordinated with the National
Marine Fisheries Service and the North Carolina Division of Marine
Fisheries. The Corps should ensure that all rock rubble created
through blasting is removed from the ocean floor so that it does
not destroy trawling nets.
10. To protect nearby beach habitats, limit the amount of sand
removed from the littoral system by using suitable material
dredged from the channel for beach nourishment of eroding adjacent
beaches, rather than placing high quality sand offshore at the
Ocean Dredged Material Disposal Site. The Corps should determine
the sediment budget of the area and determine how deepening the
channel will affect the sediment budget.

62

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•
SUMMARY
of utmost concern to the Service is the potential use of blasting
for removal of rock underneath the channel. Blasting will result
in the mortality of fish and invertebrates including larvae and
potentially of right whales and other marine mammals, sea turtles,
West Indian manatees, and shortnose sturgeon if they happen to be
within a certain radius of the blasts. Careful time-of-year
planning will be necessary if blasting is used, but it will be
very difficult to avoid impacts to all species of concern,
including Federally-listed species, due to different critical time
periods at which the species are potentially utilizing the channel
and surrounding waters. Pre-blasting surveys will be required to
ensure that West Indian manatees are not within the lethal range
of the blast site at the time of blasting. Surveys for other
endangered and threatened species may be required, but the
National Marine Fisheries Service has jurisdiction over other
listed species potentially in the impact. area. If blasting is
required, post-blasting monitoring should be implemented so that
we get an understanding of the species and number of organisms
killed by the blasts. Dredging also will result in mortality, of
sessile species and those unable to escape the dredge head.
Seasonal constrictions also will be necessary for dredging
activities in order to minimize impacts to finfish and
invertebrate larvae.
63

r
i
Although it appears that rock removed by dredging will not be of
an appropriate size to provide suitable reef habitat, the Corps
has indicated that if blasting occurs, rock removed may be large
enough to be used in artificial reef construction. We support the
Corps' plans to make this rock available to the North Carolina
Division of Marine Fisheries for artificial reef construction, but
the Service recommends any such plan be closely coordinated with
the National Marine Fisheries Service and the North Carolina
Division of Marine Fisheries.

Further study is necessary to assess the potential for Wilmington
Harbor dredging activities to increase saltwater intrusion up the
Cape Fear River. An appropriate mitigation plan should be
developed and implemented, in close coordination with the Service,
for the cumulative loss and.. .conversion of forested wetlands
resulting from all Wilmington Harbor dredging activities.
Sand removed from the channel during initial construction or
maintenance dredging, if compatible with natural beach sand,
should be used for beach nourishment of adjacent beaches rather
than removing the material from the littoral zone.
64
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f
s
LITERATURE CITED
American Fisheries Society. 1980. A List of Common and
Scientific Names of Fishes from the United States and Canada.
4th ed. American Fisheries Society, Washington, DC. 174 pp.
Banks, R.C., R.W. McDiarm-id, and A.L. Gardner. (eds.) 1987.
Checklist of vertebrates of the United States, the U.S.
territories, and Canada. U.S. Fish and Wildlife Service,
Resource Publication 166. 79 pp.

Coker, C.M. and E.H. Hollis. 1950. Fish mortality caused by
a series of heavy explosions in Chesapeake Bay. Journal of
Wildlife Management. 14(4):435-444.
EA Engineering, Science and Technology. 1992. Fish monitoring
data for 21 blasts conducted between May 11, 1992 and May 17,
1992 and for 9 blasts conducted between May 25 and May 30 for
the Central Artery Tunnel Project. EA Engineering, Science
and Technology, Sharon, Massachusetts.
EA Engineering, Science and Technology, Barnes-Williams
Environmental Consultants, and Sonalysts, Inc. 1992a. Final
Draft - Monitoring Program for Anadromous Fish during
Blasting operations associated with the Central Artery/Tunnel
Project. EA Engineering, Science and Technology, Sharon, Massachusetts.
65

r
" Fitch, J.E. and P.H. Young. 1948. Use and effect of
explosives in California coastal waters. California Fish and
Game. 34(2):53-73.
Hackney, C.T. and G.F. Yelverton. 1990. Effects of human
activities and sea level rise on wetland ecosystems in the
Cape Fear River Estuary, North Carolina, USA. Pp 55-61 In
D.F. Whigham, R.E. Good, and J. Kvet (eds). Wetland Ecology
and Management: Case Studies. Kluwer Academic Publishers,
the Netherlands.
Hubbs, C. L. and A.B. Rechnitzer. 1952. Report on
experiments designed to determine effects of underwater
explosives on fish life. California Fish and Game.
38(3):333-366.
•
Inman, D.L., R.G. Dean, R. Dolan, J. Schmertmann, and D.G.
Aubrey. 1989. Protection of Bonner Bridge, Oregon Inlet,
North Carolina. Report prepared for Fish and Wildlife
Service and National Park Service, U.S. Department of the
Interior. 28 pp. + App.
Linton, T.L., N. Hall, D. Labomascus and A. Landry. 1985.
The Effects of Seismic Sounds on Marine Organisms: an
Annotated Bibliography and Literature Review. Texas A & M
University, Galveston, Texas. 67 pp.
66

National Marine Fisheries Service. 1993. Marine Recreational
Fisherman Statistics Survey Data. National Marine Fisheries
Service, Southeastern Fisheries Science Center, Beaufort,
North Carolina.
North Carolina Coastal Resources Commission. 1990. Final
Report of the Maritime Forest Working Group. North Carolina
Department of Environment, Health and Natural Resources,
Division of Coastal Management, Raleigh, N.C. 31 pp. + App.
Parnell, J.F. and M.A. Shields. 1990. Management of North
Carolina's Colonial Waterbirds. National Oceanic and
Atmospheric Administration. UNC Seagrant Publication Number
UNC-SG-90-03. 169 pp.
Radford, A.E., H.A. Ahles, and C.R. Bell. 1968. Manual of
the Vascular Flora of the Carolinas. University of North
Carolina Press, Chapel Hill, North Carolina. 1183 pp.
Rasmussen, B. 1967. The effect of underwater explosions on
marine life. Bergen, Norway. 17p. In Falk, M.R. and M.J.
Lawrence. 1973. Seismic exploration: its nature and effect
on fish. CEN T-73-9.
Schwartz, F.J., P. Perschbacher, M. Mcadams, L. Davidson, K.
Sandoy, C. Simpson, J. Duncan and D. Mason. 1979. An
67
•

Ecological Study of Fishes and Invertebrate Macrofauna
Utilizing the Cape Fear River Estuary, Carolina Beach Inlet
and Adjacent Atlantic Ocean, Summary Report 1973 - 1977.
Institute of Marine Science, University of North Carolina,
Morehead City, North Carolina, 568 pp.
U.S. Minerals Management Service. 1990. Final Environmental
Report on Proposed Exploratory Drilling Offshore North
Carolina. Volume I. Minerals Management Service, Atlantic
OCS Region, Herndon, VA. 669 pp.
U.S. Army Corps of Engineers. 1988. Draft Reconnaissance
Report. Wilmington Harbor Passing Lane. Wilmington
District, Corps of Engineers, Wilmington, NC. 149 pp.
0
1989a. Reconnaissance Level Study, Wilmington
Harbor - Turns and Bends. Wilmington District, Corps of
Engineers, Wilmington, NC. 37 pp + App.
. 1989b. Final Environmental Impact Statement for
Long-Term Maintenance of Wilmington Harbor, North Carolina.
Wilmington District, U.S. Army Corps of Engineers,
Wilmington, NC. 100 pp + App.
68

1990a. Draft Feasibility Study Wilmington
Harbor Turns and Bends. Wilmington District, Corps of
Engineers, Wilmington, NC. 14 pp + App.
1990b. Final Supplement to the Final
Environmental Impact Statement.- Wilmington Harbor Northeast
Cape Fear River. Wilmington District, Corps of Engineers,
Wilmington, NC. 106 pp + App.
1990c. Wilmington Harbor - Bald Head Island
Evaluation Report. Wilmington District, Corps of Engineers,
Wilmington, NC. 44 pp + App.
1991a. Environmental Assessment and Finding of
No Significant Impact for Maintenance Dredging in Wilmington
Harbor Ocean Bar Channels. Wilmington District, U.S. Army
Corps of Engineers, Wilmington, NC. 8 pp + App.
1991b. Final Reevaluation Report - Wilmington
Harbor Ocean Bar Channel Deepening. Wilmington District,
U.S. Army Corps of Engineers, Wilmington, NC. 23 pp + App.
1992. Reconnaissance Report on Improvement of
Navigation Cape-Fear - Northeast Cape Fear Rivers Wilmington
Harbor, North Carolina. Wilmington District, U.S. Army Corps
of Engineers, Wilmington, N.C. 11 pp + App:
V
69
0
A
v
1993a. Environmental Assessment and Finding of
No Significant Impact (EA/FONSI) - Project Modification and
Mitigation Plan Wilmington Harbor - Northeast Cape Fear
River, New Hanover and Brunswick Counties, North Carolina.
Wilmington District, Wilmington, North Carolina.
1993b. Draft Project Description, Wilmington
Harbor Ocean Bar, April, 1993. Wilmington District, U.S.
Army Corps of Engineers, Wilmington, N.C. 1 p.
1993c. Draft Project Description, Wilmington
Harbor Ocean Bar, May, 1993. Wilmington District, U.S. Army
Corps of Engineers, Wilmington, N.C. 4 pp.
.
U.S. Fish and Wildlife Service. 1988a. Planning Aid Report -
•
Wilmington Harbor Passing Lane. Raleigh Field Office,
Raleigh, NC. 36 pp.
. 1988b. Final Fish and Wildlife Coordination
Act Report. Wilmington Northeast Cape Fear River. Raleigh
Field Office, Raleigh, NC. 24 pp + App.
1989.
Turns and Bends.
Planning Aid Report. Wilmington Harbor
Raleigh Field Office, Raleigh, NC. 31 pp.
70

1990. Draft Fish and Wildlife Coordination Act
Report. Wilmington Harbor Passing Lane. Raleigh Field,
Office, Raleigh, NC. 51 pp.
1991. Draft Fish and Wildlife Coordination Act
Report. Wilmington Harbor Turns.and Bends. Raleigh Field
Office, Raleigh, NC. 55 pp.
Van Dolah, R.F. and D.M. Knott. 1984. A Biological
Assessment of Beach and Nearshore Areas along the South
Carolina Grand Strand. Final Report to U.S. Department of
the Interior, Fish and Wildlife Service. Marine Resources
Division, South Carolina Wildlife and Marine Resources
Department, Charleston, South Carolina, 58 pp.
Weakley, A.S. and M.A. Bucher. 1992. Status survey of
seabeach amaranth (Amaranthus pumilus Rafinesque) in North
and South Carolina, second edition (After Hurricane Hugo).
Report to North Carolina Plant Conservation Program, North
Carolina Department of Agriculture, Raleigh, N.C. and
Endangered Species Field Office, United States Fish and
Wildlife Service, Asheville, North Carolina. 178 pp.
Webster, W.D., J. F. Parnell, and W. C. Biggs. 1985. Mammals
of the Carolinas, Virginia and Maryland. The University of
North Carolina Press, Chapel Hill, North Carolina. 255 pp.
71
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1
United States Department of the Interior
FISH AND WILDLIFE SERVICE
Ecological Services
Post Office Box 33726
Raleigh, North Carolina 27636-3726
¦
TAKES
PRIDE INS
AMEMCA? M
September 3, 1993
Mr. John Dorney
N.C. Division of Environmental Management
Post Office Box 29535
Raleigh, North Carolina 27626-0535
Dear Mr. Dorney:
J-I 'r
Attached is the Service's Final Fish and Wildlife Coordination
Act (FWCA) Report for the Wilmington Harbor Ocean Bar Channel
Deepening Project, New Hanover County, North Carolina. This
report identifies baseline fish and wildlife resources in the
general study area, discusses the Corps' proposed study and the
various alternatives, potential impacts to natural resources
and makes recommendations to the Corps on this project.
Sincerely yours,
u. td (
L.K. Mike Gantt
Supervisor
SEP 1 0 1993

j?
M11.P
r

U.S. DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
Raleigh Field Office
551 F Pylon Drive
Post Office Box 33726
Raleigh, North Carolina 27636-3726
On,
v

4
ti
r
14
Ob.
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
FINAL FISH AND WILDLIFE
COORDINATION ACT REPORT
Prepared by
Karen R. Warr
L.K. Mike Gantt
Supervisor
Released by
U.S. Fish and Wildlife Service
Raleigh, North Carolina
August 1993

United States Department of the Interior
FISH AND WILDLIFE SERVICE
Ecological Services
Post Office Box 33726
Raleigh, North Carolina 27636-3726
August 31, 1993
Colonel George L. Cajigal
District Engineer
U.S. Army Corps of Engineers
P.O. Box 1890
Wilmington, North Carolina 28401-1890
Dear Colonel Cajigal,
TAKE?? i
PRIDE INMEN
AMERICAN ? w
ENNNNENMN?
Attached is the Service's Final Fish and Wildlife Coordination
Act Report (Report) for the Wilmington Harbor Ocean Bar
Channel Deepening Reevaluation Study. This Report identifies
fish and wildlife resources located within the project area
and provides recommendations designed to minimize impacts to
these resources.
The Service is very concerned that blasting will be required
in order to remove rock from underneath the channel. If
blasting is required, it will result in the mortality of an
undetermined number of organisms within the vicinity,
potentially including Federally-listed endangered and
threatened species such as northern right whales, shortnose
sturgeon, West Indian manatees, and loggerhead sea turtles.
We strongly recommend that blasting should be avoided if at
all possible. If blasting is required, measures to minimize
the size of the lethal zone and the potential adverse impacts
to fish and wildlife resources must be implemented.
Although it appears that rock dredged from the channel will be
in pieces too small to be high value reef material, if
blasting occurs, rock of appropriate size for artificial reefs
may result. We support the Corps' preliminary plans to offer
this material to the North Carolina Division of Marine
Fisheries Artificial Reef Program for use in constructing an
artificial reef provided it is of high quality and free of
contaminants. An artificial reef created with natural rock
would provide substrate for marine organisms to attach and
grow, would provide excellent foraging habitat and would serve
as a refuge for fish and other organisms.

In our view, the planning for this project is not as advanced
as it usually is at this stage in the process. Specifically,
it is not known if blasting will be required, and a
comprehensive biological monitoring plan has not yet been
developed. In view of this, the Fish and Wildlife Service
will be pleased to continue to provide technical biological
assistance to the Corps as detailed project design proceeds.
Should blasting be required, the Service recommends that a
comprehensive biological monitoring plan be developed in
conjunction with our agency, National Marine Fisheries
service, and appropriate State agencies, and we reserve the
right to review and approve that plan.
We appreciate the opportunity to provide this report, and we
look forward to continued involvement in this project.
Sincerely,
L)(-K4-0- Q-'?
L.K. Mike Gantt
Supervisor
M
® North Carolina Wildlife Resources Commission
512 N. Salisbury Street, Raleigh, North Carolina 27604-1188, 919-733-3391
Charles R. Fullwood, Executive Director
August 20, 1993
Mrs. L. K. Mike Gantt
USDI-Fish & Wildlife Service
Raleigh Field Office
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Dear Mrs. Gantt:
Biologists on our staff have completed their review of the
Service's Draft Fish and Wildlife Coordination Act Report for the
Wilmington Harbor Ocean Bar Channel Deepening Project. The
report is well written and comprehensive. It appropriately
identifies fish and wildlife species that could be affected by
the project and provides sound recommendations for avoiding or
minimizing impacts. We share your concerns regarding mortality
from blasting as a means for removing rock substrate. Although
our jurisdiction is limited to wildlife and inland fisheries,
this letter is to advise you that the Wildlife Resources
Commission fully concurs with findings and recommendations of the
report.
Thank you for the opportunity to review and comment on this
report. If we can provide further assistance, please call on us.
Sincerely,
Richard B. Hamilton
Assistant Director
CC: Bennett Wynne, District 2 Fisheries Biologist
Al1G 2 0 1993
EXECUTIVE SUMMARY
This Final Fish and Wildlife Coordination Act Report contains
planning information pursuant to the U.S Fish and Wildlife
Service's responsibilities under the general authority of the
Fish and Wildlife Coordination Act, as amended (48 Stat.
401;16 U.S.C. 661-667) for the Wilmington Harbor Ocean Bar
deepening project. Project plans call for deepening the
channel to its authorized depth of 40 feet plus 1 foot of
overdepth for areas underlain by rock and 2 feet additional
allowable overdepth to account for dredging inconsistencies.
Thus, in areas where rock is present, the channel will be
deepened to a maximum depth of 43 feet and where rock is not
present the channel will be deepened to a maximum depth of 42
feet. The project is authorized by the River and Harbor and
Flood Control Act of 1962 and is described in Senate Document
No. 114, 87th Congress, 2nd session.
Initial deepening will require the removal of approximately
830,000 cubic yards (cy) of limestone rock and approximately
100,000 cy of sand, silt, clay, and shell fragments over the
amount that is currently removed during maintenance dredging.
It is estimated that less than two percent of the total rock
or less than 14,000 cubic yards may be non-dredgeable and may
require blasting.
Of utmost concern to the Service is the potential use of
blasting for removal of rock underneath the channel. Blasting
will result in the mortality of fish and invertebrates
including larvae and potentially of right whales and other
marine mammals, sea turtles, West Indian manatees, and
shortnose sturgeon if they happen to be within a certain
radius of the blasts. Careful time-of-year planning will be
necessary if blasting is used, but it will be very difficult
to avoid impacts to all species of concern, including
Federally-listed species, due to different critical time
periods at which the species are potentially utilizing the
channel and surrounding waters. Pre-blasting surveys will be
necessary to determine if West Indian manatees are within the
lethal zone of the blast site and detonation will be postponed
until the area is free of manatees. Monitoring for other
Federally-listed species and marine mammals which may occur
within the project area may be necessary but the National
Marine Fisheries Service has jurisdiction over those species.
The Service recommends that post- blasting monitoring be
conducted in order to assess the extent of mortality and
injury to fish caused by blasting.
Dredging also will result in mortality, of sessile species and
those unable to escape the dredge head. Seasonal
constrictions will be necessary for dredging activities in
order to minimize impacts to finfish and invertebrate larvae.
Although it appears that rock removed by dredging will not be
of an appropriate size to provide suitable reef habitat, the
Corps has indicated that if blasting occurs, rock removed may
be large enough to be used in artificial reef construction.
We support the Corps' plans to make this rock available to the
North Carolina Division of Marine Fisheries for artificial
reef construction, but the Service recommends any such plan be
closely coordinated with the National Marine Fisheries Service
and the North Carolina Division of Marine Fisheries.
TABLE OF CONTENTS
Introduction 1
Purpose, Scope and Authority 1
Coordination with State and Federal Agencies 2
Prior Studies 2
Study Site Description 3
Fish and Wildlife Resource Concerns and Planning Objectives 6
Evaluation Methods 7
Existing Fish and Wildlife Resources 7.
Marine and Estuarine Waters 8
Intertidal Oyster Reefs 11
Intertidal Flats 11
Marsh 11
Forested Wetlands 12
Colonial Waterbird Islands 12
Barrier Island Communities 13
Intertidal Beach 13
Upper Beach and Berm 13
Dunes 13
Maritime Shrub Thicket/Forest 14
Federally-Listed Endangered and Threatened Species 14
Future of Project Area Without the Project 18
Description of Alternatives 19
Description of Impacts 22
Impacts Related to Dredging 22
Impacts Related to Blasting 23
Impacts Related to the Deepening of the Channel 25
Impacts Related to Disposal of Material Removed from
Channel 26
Comparison of Alternatives 27
Fish and Wildlife Conservation Measures 28
Recommendations 32
Summary 35
Literature Cited 36
FIGURES
Figure 1: Study Area Showing Wilmington Harbor Ocean Bar
(Baldhead Shoal) Channel, Bald Head Island and
Oak Island 4
Figure 2: Wilmington Harbor Ocean Bar (Baldhead Shoal)
Channel and Other Channels in the Area 5
INTRODUCTION
Purpose, Scope and Authority
The Wilmington Harbor Ocean Bar Project involves the deepening
of the Wilmington Harbor Ocean Bar Channel, also called the
Baldhead Shoal Channel, to its authorized depth of 40 feet
plus 1 foot of overdepth for areas underlain by rock and 2
feet additional allowable overdepth to account for dredging
inconsistencies. Thus, in areas where rock is present, the
channel will be deepened to a maximum depth of 43 feet and
where rock is not present the channel will be deepened to a
maximum depth of 42 feet. The project is authorized by the
River and Harbor and Flood Control Act of 1962 and is
described in Senate Document No. 114, 87th Congress, 2nd
Session.
Between 1968 and 1973, the channel was widened and deepened.
Although the deepening was authorized to 40 feet,
unanticipated rock was encountered preventing deepening past
38.5 feet. An inaccurate tide gage led the U.S. Army Corps of
Engineers (Corps) to believe the channel was actually 40 feet
deep. However, when the tide gage was replaced two years ago,
the actual depth of 38.5 feet was revealed. Due to rapid
shoaling in the area, the current depth of 38.5 feet is
available only.50 percent of the year, and approximately 1
foot less is available in the Ocean Bar Channel the remainder
of the year. Vessels require approximately 2 feet more
clearance in the Ocean Bar Channel than in the river channels
due to wave action. The North Carolina State Port Authority
and vessel pilots have requested a deeper bar channel so that
rock outcroppings can be avoided and the overall efficiency of
navigation through Wilmington Harbor can be improved.
This report is provided in accordance with provisions of the
Fish and Wildlife Coordination Act (48 Stat. 401, as amended;
16 U.S.C. 661-667) and pursuant to the U.S. Fish and Wildlife
Service's (Service) responsibilities under the Scope of Work
Agreement for FY 93. This report constitutes the final report
of the Secretary of the Interior as required by Section 2(b)
of the Fish and Wildlife Coordination Act, as amended.
The purpose of this report is to describe the fish and
wildlife resources within the study area, to assess the
potential impacts to fish and wildlife resources, to discuss
fish and wildlife resource problems and conservation
opportunities, and to recommend measures to conserve fish and
wildlife resources.
1
Coordination with State and Federal Aaencies
In preparation of this report, the Service coordinated with
the National Marine Fisheries Service (NMFS), the North
Carolina Wildlife Resources Commission (NCWRC), the North
Carolina Division of Marine Fisheries (NCDMF), and the North
Carolina Division of Coastal Management (NCDCM).
Prior Studies
Related projects include those Corps studies associated with
other sections of Wilmington Harbor. The Wilmington Harbor
Turns and Bends Project involves the widening of six channel
turns and bends.(U.S. Army Corps of Engineers [hereafter
USACOE] 1989a, USACOE 1990a, U.S. Fish and Wildlife Service
[hereafter USFWS] 1989, and USFWS 1991). The Wilmington
Harbor Passing Lane Project involves the creation of a passing
lane about midway between the mouth of the Cape Fear and the
port of Wilmington (USACOE 1988, USFWS 1988a, and USFWS 1990).
These two projects are now being combined into one project
known as the Wilmington Harbor Channel Widening Study.
The Wilmington Harbor-Northeast Cape Fear River project
involves navigation improvements in the upper reaches of
Wilmington Harbor. The most recent reports regarding this
project are the Final Supplement to the Final Environmental
Impact Statement (USACOE 1990b), the Environmental Assessment
and Finding of No Significant Impact regarding project
modifications and the mitigation plan (USACOE 1993a) and the
Final Fish and Wildlife Coordination Act Report (USFWS 1988b).
The Corps also has prepared a Final Environmental Impact
Statement for Long-Term Maintenance of Wilmington Harbor,
North Carolina (USACOE 1989b).
To assess further deepening and widening of Wilmington Harbor,
the Corps is conducting a comprehensive study of navigation
improvements. The Wilmington Harbor Comprehensive Study
involves an overall approach to widening and deepening
projects in the harbor along its entire length from the Ocean
Bar Channel to a point on the Northeast Cape Fear River
approximately 1.7 miles upstream of the Hilton Railroad Bridge
above Wilmington (USACOE 1992). The Comprehensive Study will
assess further deepening of Wilmington Harbor channels
including the Ocean Bar Channel, widening of two turning
basins, and additional modifications to the channel turns and
bends and the passing lane (USACOE 1992).
An Environmental Assessment and Finding of No Significant
Impact for Maintenance Dredging in Wilmington Harbor Ocean Bar
2
Channels was prepared by the Corps (USACOE 1991a). Bald Head
Island Beach nourishment was discussed in the Wilmington
Harbor-Bald Head Island Evaluation Report (USACOE 1990c).
For the current project - Wilmington Harbor Ocean Bar Channel
Deepening, the Corps has provided a Reevaluation Report which
concluded that the improvements are economically feasible and
can be implemented without additional Congressional
authorization (USACOE 1991b). They are currently preparing an
Environmental Assessment for the project.
STUDY SITE DESCRIPTION
The study area is located in southeastern North Carolina off
the coast of Brunswick County (Figure 1). The Wilmington
Harbor Ocean Bar Channel is located at the mouth of the Cape
Fear River between Bald Head Island to the east and Oak Island
to the west. Bald Head Island is actually part of a three
island complex known as the Smith Island Complex. The town of
Southport is on the mainland landward of the channel to the
northwest. Wilmington Harbor is divided into several
channels. The outer, seaward portion is called the Baldhead
Shoal or Ocean Bar Channel. Moving upriver toward Southport,
the four adjacent upstream channels are the Smith Island
Channel, Baldhead-Caswell Channel, Southport Channel, and
Battery Channel (Figure 2). At Southport, the channel turns
northward and extends up to the port of Wilmington, located
approximately 26 river miles upstream from the mouth of the
river.
The Ocean Bar Channel is about 38.5 feet deep below mean low
water (mlw) and 500 feet wide. The channel is approximately
24,000 feet long and oriented in a northeast-southwest
direction. From the upstream limit of the ocean bar channel
to Southport, the authorized depth of 40 feet has been
reached. Between Southport and Wilmington, a 38-foot deep by
400-foot-wide channel is available. Approximately 82 percent
of commerce in Wilmington Harbor results from deepdraft ocean
going trade. Vessels with drafts of over 32 feet cannot
transit the Ocean Bar Channel without waiting for high tide.
Many vessels calling at the Port of Wilmington require light
loading in order to transit the ocean bar and those drafting
over 36 feet must be light loaded even at high tide (USACOE
1992). The deficiency in the ocean bar limits the use of the
entire Wilmington Harbor project (USACOE 1992). According to
the Corps, even if the ocean bar channel is deepened to its
authorized 40-foot depth, light loading and tidal delays would
still occur for some ships based on projections of future
vessel sizes and historical data (USACOE 1992).
3
TO WILMINGTON
N
FISHER
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Off'
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P?
Q?
Vp
ATLANTIC OCEAN
FIGURE I - STUDY AREA SHOWING WILMINGTON HARBOR OCEAN BAR
(BALDHEAD SHOAL) CHANNEL, BALD HEAD ISLAND AND OAR ISLAND.
?-,?-BATTERY ISLAND
-,?-? SOUTHPORT
.*--BALDHEAD-
?? `CASWELL
" 0 Island
SMITH ISLAND"1`
SHOAL

V`531
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gT?AIVT
?c OCEAN
- Channel to Be Deepened
4000 2000 0 4000 8000
SCALE IN FEET (1:50. 000)

WILMINGTON HARBOR. NORTH CAROLINA
WILMINGTON HARBOR
BAR CHANNEL
FIGURE 2 - WILMINGTON HARBOR OCEAN BAR (BALDHEAD SHOAL)
CHANNEL AND OTHER CHANNELS IN THE AREA
Source: U.S. Army Corps of Engineers 1991b.
n
Cn
Salinities around the mouth of the Cape Fear River are
generally greater than 10 parts per thousand (ppt) during
spring, and they increase to about 32 ppt by fall (Schwartz et
al. 1979). Saline water reaches a considerable distance up
the Cape Fear River as a result of dredging activities and sea
level rise. During the past century, drastic changes in
community structure have occurred as saltwater intrusion has
converted freshwater wetlands into salt marsh in the middle
reaches of the estuary and into oligohaline marshes in the
upper reaches of the estuary. The salt marshes of the lower
reaches of the estuary have not changed (Hackney and Yelverton
1990).
The channel is underlain by bedrock. Limestones of either the
Eocene Castle Hayne type or the Cretaceous Peedee Formation
lie at the top of the rock. The precise thickness and extent
of these rock types is unknown under the channel. The
thickness of the rock types and the hardness may vary
considerably along short distances. In some areas the Castle
Hayne limestone may be cemented and in other sections, it may
be softer and easier to break (Bill Hoffman, North Carolina
Geological Survey, personal communication, August, 1992). The
upper layer of the Peedee formation limestone is generally
harder than the Castle Hayne formation (USACOE 1991b). Rock
from both the Castle Hayne limestone and the Peedee formation
has required blasting in other portions of the Cape Fear
River.
FISH AND WILDLIFE RESOURCE CONCERNS AND PLANNING OBJECTIVES
The involvement of the Service in this study is in response to
a Congressional mandate through the Fish and Wildlife
Coordination Act which directs that fish and wildlife resource
conservation shall receive full and equal consideration and be
coordinated with other features of Federal projects.
Fish and wildlife resource concerns associated with this
project center primarily around the potential impacts to
marine resources within the vicinity of the proposed project
including important fishery resources, marine mammals, and sea
turtles which may be in the area during deepening activities.
Also of concern are: (1) the potential for the project to
alter the sand budget system and affect littoral transport of
sand adjacent to Bald Head Island and other shorelines in the
area; (2) the potential of the project to result in larger
vessel use of Wilmington Harbor resulting in larger wakes
possibly increasing the erosion of estuarine shorelines,
including colonial waterbird nesting islands; and (3)
6
potential impacts to freshwater wetlands along the Cape Fear
River near Wilmington resulting from cumulative impacts of
deepening the harbor, thus, increasing saltwater intrusion in
the river.
The Service proposes the following planning objectives for the
study:
1. Conduct harbor deepening activities in the manner least
likely to result in the mortality of marine life. The
alternative of blasting should be viewed as a last resort and
conducted only after demonstrating'that rock can
removed by dredging or any other environmentally
method.
not be
acceptable
2. Use suitable rock removed from the channel for creation of
an artificial reef in coordination with the National Marine
Fisheries Service and the North Carolina Division of Marine
Fisheries.
3. Consider using suitable sand dredged from the channel for
nourishment of Bald Head Island, Oak Island, Battery Island,
or dredged disposal islands within the Cape Fear River which
are used by colonially nesting waterbirds.
In accordance with the Fish and Wildlife Coordination Act, as
amended, these planning objectives should be given full and
equal consideration with other features of the study area.
The following sections define the existing fish and wildlife
habitat values, assess the potential impacts of the proposed
plan, and provide the Service's recommendations for habitat
conservation and enhancement.
EVALUATION METHODS
Descriptions of natural resources present within the study
area and assessments of anticipated impacts to these resources
are derived from review of published literature, personal
communications with Corps biologists, biologists from other
natural resource agencies, and with recognized authorities on
local fish and wildlife resources. Nomenclature in this
report follows Radford et al. (1968) for plants; the American
Fisheries Society (1991) for fish; and Banks et al. (1987) for
birds, reptiles, amphibians, and mammals.
EXISTING FISH AND WILDLIFE RESOURCES
The study area includes marine waters around the ocean bar
channel and estuarine waters further upstream in the Cape Fear
7
River, as well as terrestrial and wetland communities
associated with nearby barrier islands, dredged material
disposal islands, and the mainland areas bordering the Cape
Fear River. The following habitats may potentially be
affected by the project and are discussed in this report:
marine and estuarine waters; estuarine intertidal oyster.
reefs; intertidal flats; marsh communities; forested wetlands;
colonial waterbird nesting islands; and barrier island
communities categorized as intertidal beach, upper beach,
dunes, and maritime shrub thicket/forest. Fish and wildlife
resources are discussed for these habitats.
Marine and Estuarine Waters
Trawling surveys conducted as part of a study concerning the
effects on aquatic resources of the Carolina Power and Light
nuclear power plant in Southport demonstrate that the Cape
Fear River and nearby ocean waters are utilized by a diverse
group of invertebrates and fish species (Schwartz et al.
1979). The most abundant invertebrate species were
arthropods, such as the blue crab (Callinectus sapidus), the
lesser blue crab (Callinectus similis), mantis shrimp (Squilla
empusa), penaed shrimp (Penaeus aztecus, P.duorarum, P.
setiferus), and grass shrimp (Palaemonetes sp.) ; echinoderms,
such as the common sea star (Asterias forbesi) and sand dollar
(Mellita quinquiesperforata); jellyfish (Scyphozoa) and other
cnidarians; comb jellies (Ctneophora); and various mollusks
such as oysters (Crassostrea virginica), Atlantic brief squid
(Lolliguncula brevis), conchs and whelks (Melongenidae), and
mud snails (Nassariidae). Many other invertebrate species
were found in smaller numbers.
Common fish species in the Cape Fear River Estuary and
nearshore ocean waters include menhaden (Brevoortia tyrannus),
spot (Leiostomus xanthurus), grey trout (Cynoscion regalis),
spotted hake (Urophycis regius), Atlantic croaker (Micropogon
undulatus), star drum (Stellifer lanceolatus), anchovies
(Anchoa spp.), summer flounder (Paralicthys dentatus), and
southern flounder (Paralicthys lethostigma). Many of these
are estuarine dependent species, spawning offshore and moving
into the estuarine waters as larvae. The Ocean Bar Channel is
a migration route for these species as they move into the
estuary as larvae and as they migrate back into the ocean as
juveniles or adults.
Anadromous species such as blueback herring (A1osa
aestivalis), alewife (A1osa pseudoharengus), American shad
(Alosa sapidissima), and Atlantic sturgeon (Acipenser
oxyrhynchus) move up rivers into fresh or brackish water to
8
spawn primarily during January, February, and March. The
shortnose sturgeon (Acipenser brevirostrum), a Federally-
listed endangered species, is an anadromous species which is
known to inhabit the Cape Fear River estuary. Although there
are still a lot of unknowns regarding the shortnose sturgeon
population in the Cape Fear River, numbers of the species
within the estuary appear to be very low. Dr. Mary Moser and
Dr. Steve Ross of the University of North Carolina at
Wilmington have been studying sturgeon within the Cape Fear
River for the past few years. During three years, they caught
over 100 Atlantic sturgeon, and only 9 shortnose sturgeon (Dr.
Mary Moser, personal communication, April, 1993). It is
unknown whether or not the Cape Fear River shortnose sturgeon
are making an ocean run or are remaining in the lower estuary
during the summer months. If they are making ocean runs, they
must be migrating through the general ocean bar area.
However, their presence in the ocean bar area has not been
documented. According to Dr. Moser, sturgeon within the Cape
Fear River appeared to stick to the main channel and appear to
be attracted to areas with deep holes. Atlantic sturgeon
associate with the deepest parts of the river during the
hottest times of the year.
Marine mammals occur in offshore and inshore waters of North
Carolina. Some species occur farther offshore than project
limits, and others occur in the waters closer to shore. The
sperm whale (Physeter macrocephalus) is a year round resident
of the shelf edge and pelagic waters off North Carolina,
probably moving farther offshore during the winter. The
Federally-endangered right whale (Balaena glacialis) and
humpback whale (Megaptera novaeangliae) are spring and fall
migrants off of North Carolina. Both species may be found in
nearshore waters, and the right whale appears to prefer
shallow waters. Although the following species are generally
found in deeper waters, limited beach strandings have been
recorded in North Carolina for these species: dwarf sperm
whale (Kogia simus), pygmy sperm whale (Kogia breviceps),
True's beaked whale (Mesoplodon mirus), killer whale (Orcinus
orca), short-finned pilot whale (Globicephala macrochynchus),
and spinner dolphin (Stenella longirostris) (Webster et al.
1985). Bottle-nosed dolphins (Tursiops truncatus) and harbor
porpoises (Phocoena phocoena) utilize nearshore waters
including bays, estuarine creeks, and sounds. They are the
most common cetaceans in the area. Bottlenose dolphins are
commonly observed in the estuarine waters between Bald Head
Island and Southport.
Five sea turtle species inhabit the coastal waters of North
Carolina. The loggerhead sea turtle (Caretta caretta) is the
9
most common in the coastal area as it regularly nests on North
Carolina beaches. Most sightings of Kemp's ridley sea turtles
(Lepidochelys kempii) off the North Carolina coast have been
within a few miles of shore. During the 1992 nesting season,
a Kemp's ridley sea turtle nested on Long Beach to the south
of the study site (Therese Conant, Sea Turtle Coordinator,
N.C. Wildlife Resources Commission, personal communication,
July 1992). Green sea turtles (Chelonia mydas) have been
documented to have nested on southern beaches in the past few
years including one record on Bald Head Island. The
hawksbill sea turtle (Eretmochelys imbricata) is rare north of
Florida, but there have been limited sightings off the North
Carolina coast. The leatherback sea turtle (Demochelys
coriacea) is found between 10 to 30 miles offshore during
April through October and seldomly comes closer into shore
(U.S. Minerals Management service (hereafter USMMS) 1990).
Kemp's ridley, loggerhead and green sea turtles utilize the
Cape Fear River estuary at times, primarily during the warmer
months. Leatherback sea turtles have been documented within
Core and Pamlico Sounds and may possibly occur within the Cape
Fear River. Hawksbill sea turtles are extremely rare in North
Carolina, but one was found at the Carolina Power and Light
Plant in Southport several years ago (Sherry Epperly, National
Marine Fisheries Service, Beaufort Laboratory, personal
communication, April, 1993). Between 1990 and 1991, 12 sea
turtles were observed in the Cape Fear River by recreational
fishermen (National Marine Fisheries Service 1993). In more
southern areas it has been documented that sea turtles bury
into inshore sediments during cooler months. However, this
"mudding in" has not been documented in inshore waters of
North Carolina and it is unknown whether or not it occurs in
North Carolina.
American alligators (Alligator mississippiensis) are known to
occur in the Cape Fear River and surrounding habitats.
Alligator tracks have been observed on dredge disposal islands
near the project site, and a few alligators inhabit Bald Head
Island.
The Cape Fear River estuary is utilized by waterfowl with over
12 species observed during the Service's 1988 through 1993
mid-winter waterfowl surveys (Otto Florschutz, U.S. Fish and
Wildlife Service, Migratory Bird Field Coordinator, personal
communication, April, 1993). The most common species observed
include the mallard (Anas platyrhynchos), American black duck
(Anas rubripes), ring-necked duck (Aythya collaris),
bufflehead (Bucephala albeola), mergansers (Mergus sp.), and
green wing teal (Anas crecca).
10
Intertidal_Ovster Reefs
The intertidal estuarine areas in the project vicinity support
extensive oyster reefs in some locations such as around Zekes
Island, north of Bald Head Island. Oyster reefs support a
valuable fishery in the area, and the reefs are inhabited and
utilized by many species of invertebrates, fish, and birds.
Other intertidal habitats in the area include intertidal flats
and marsh communities.
Intertidal Flats
Intertidal flats support burrowing invertebrates, such as
jacknife clams (Tagelus spp.) and various polychaetes, such as
the plumed worm (Diopatra cuprea). These invertebrates are
prey for fish which forage over the intertidal flats when they
are submerged and for numerous other animals such as American
oystercatchers (Haematopus palliatus), black-bellied plovers
(Pluvialis squatarola), gulls (Lanus sp.), dunlin (Caladris
alpina), western sandpipers (Calidris mauri) and raccoons
(Procyon lotor) when the flats are exposed or when water
levels are low.
Marsh
Marshes are highly productive, essential components of
estuarine and marine food webs. They serve as nursery areas
for many fishery species and are utilized by numerous birds,
and various mammals and reptiles. Marsh communities within
the project site are of two main types: smooth cordgrass
(Spartina alterniflora) marsh and black needlerush (Juncus
roemerianus) marsh. Along the margins of the Cape Fear River
near the mouth, the marsh is primarily dominated by smooth
cordgrass. Other species of this community include sea
lavender (Limonium carolinianum), sea oxeye (Borrichia
frutescens), saltwort (Salicornia virginica), and salt meadow
cordgrass (Spartina patens). Farther upstream in the middle
portions of the estuary and within interior portions of Bald
Head and other islands, black needlerush marsh, a brackish
community, is found. These black needlerush marshes have
replaced forested wetlands due to increased tidal amplitude
and saltwater intrusion. Saltwater intrusion has occurred as
a result of dredging activities in the harbor channels and the
creation of Snow's Cut, a channel cut between the Atlantic
Intracoastal Waterway and the Cape Fear River, allowing
saltwater from Carolina Beach Inlet to move up the river.
Within the upper reaches of the estuary, oligohaline marsh is
found. Here salinities range from 0 to 5 parts per thousand.
Cattail (Typha spp.), big cordgrass (Spartina cynosuroides),
11
and wild rice (Zizania aquatica) are a few of the plants.
Dead cypress trees are found within these oligohaline marshes.
Forested Wetlands
Wooded swamps occur in areas above the influence of salt
water. The most abundant trees are bald cypress (Taxodium
distichum), black gum (Nyssa sylvatica var. biflora), red
maple (Acer rubrum), and Carolina ash (Fraxinus-caroliniana).
As saline water reaches farther upstream, wooded swamp
vegetation is dying and being replaced by oligohaline marsh.
The forested wetlands provide important habitat for many bird
species such as prothonotary warblers (Protonotaria citrea),
various woodpeckers, and wood ducks (Aix sponsa).
Colonial Waterbird Islands
The lower Cape Fear River estuary is one of the most important
colonial waterbird nesting locations in North Carolina.
Battery Island, located to the northwest of Bald Head Island
is a natural estuarine island owned and managed by the
National Audubon Society. The island contains dense maritime
shrub thicket vegetation which has supported a mixed-species
nesting rookery since at least 1928. It is used by glossy
ibis (Plegadis falcinellus), white ibis (Eudocimus albus),
cattle egret (Bubulcus ibis), little blue herons (Egretta
caeurlea), and other waders. Battery Island contains two
separate colonies - the north colony and the south colony.
Collectively, they form the largest wading bird nesting
population in North Carolina (Parnell and Shields 1990).
Several dredged material disposal islands along the lower Cape
Fear River are also used as nesting sites by colonial
waterbirds. North and South Pelican Islands and Ferry Slip
Island are closest to the study site and are used by brown
pelicans (Pelecanus occidentalis), royal terns (Sterna
maxima), and laughing gulls (Lanus atricilla). Black skimmers
(Rynchops niger), common terns (Sterna hirundo) and gull-
billed terns (Sterna nilotica) also nest on Ferry Slip Island.
South Pelican Island and Ferry Slip Island support nearly one
half of the State's brown pelican breeding population (Parnell
and Shields 1990).
Ferry Slip Island and South Pelican Island have experienced
severe erosion in the past, such that nesting by colonial
waterbirds was diminishing, and a large number of nests laid
were destroyed. In the winter of 1992, the Corps disposed of
material on Ferry Slip and South Pelican Islands, increasing
the nesting value of these islands. It is likely that these
islands will require additional disposal material in future
12
years (Dr. James Parnell, University of North Carolina at
Wilmington, personal communication, March, 1993).
Barrier Island Communities
Barrier Island communities on Bald Head Island and Oak Island
are discussed in this report because they may potentially be
affected by the project if deepening of the ocean bar channel
affects the sediment budget of the area and subsequently
affects erosion of these islands. Habitats discussed include:
intertidal beach, upper beach or berm, sand dunes, and
maritime shrub thicket/forest.
Intertidal Beach
The intertidal beach is inhabited primarily by coquina
clams (Donax variablis and Donax parvulus), mole crabs
(Emerita talpoida), and probably amphipods, such as Haustorius
species. Polychaetes and nematodes also may be important
inhabitants (Van Dolah and Knott, 1984). These invertebrate
species are important prey to fish and shorebirds, such as
sanderlings (Calidris alba), black-bellied plovers and Eastern
willets (Catoptrophorus semipalmatus).
Upper Beach or Berm
The upper beach or berm is located between the high tide
line and the dune line and is largely unvegetated. Scattered
clumps of dune building species such as sea rocket (Cakile
edentula) and possibly seabeach amaranth (Amaranthus pumilus),
a Federally-listed threatened species, are found in this area.
These plants serve as building blocks of dunes by trapping
sand. The upper beach is important nesting habitat for
loggerhead sea turtles and for shorebirds, such as Eastern
willets and American oystercatchers, and potentially for the
Federally-listed threatened piping plover (Charadrius
melodus).
Dunes
The dune community is vegetated primarily by sea oats
(Uniola paniculata) and broomsedge species (Andropogon sp.)
with scattered beach pea (Strophostyles helvola), pennywort
(Hydrocotyle bonariensis), sandspur (Cenchrus tribuloides),
sea rocket, seaside croton (Croton punctatus), beach.spurge
(Euphorbia polygoniflora), evening primrose (Oenothera
humifusa), and seaside elder (Iva imbricata). Sand dunes
provide habitat for red wing blackbirds (Agelaius phoeniceus)
13
seaside sparrows (Ammodramus maritimus), rice rats (Oryzomys
palustris), raccoons, lizards and snakes and various other
animals. They provide protection to maritime scrub-
shrub/forest habitats and other communities and structures
located landward of them.
Maritime Shrub Thicket/Forest
Maritime shrub thicket/forest habitats are vegetated by
salt spray tolerant species such as live oak (Quercus
virginiana), wax myrtle (Myrica cerifera), yaupon (Ilex
vomitoria), Eastern red cedar (Juniperus virginiana), and
catbriar (Smilax species). Closer to the stressful salt and
wind influences, a shrub thicket community exists with dense
shrubs, vines and stunted live oak trees dominating. Farther
from the harsh salt and wind influences, the shrub thicket
grades into a maritime forest. The maritime forest is
generally less stunted and has a higher plant diversity. Less
salt tolerant deciduous trees may occur in the interior
portions of the maritime forest. only few relict tracts of
maritime forests are left in North Carolina. Bald Head Island
contains an extensive maritime forest supporting the most
northerly natural saw palmetto (Serenoa repens) population
along the east coast. Maritime forests are very important
resting and foraging habitats for migratory birds, and they
are also heavily used by resident species of birds, snakes,
amphibians, mammals and fish where freshwater ponds are found.
Bald Head Island maritime forests have been categorized as
having "...much higher than average ecological diversity
compared to most remaining maritime forests...," and the
maritime forest community is described as "...one of the best
remaining maritime forests for rare species habitat..."
(North Carolina Coastal Resources Commission 1990).
Federally-listed Endangered and Threatened Species
The following Federally-listed endangered (E), threatened (T)
and threatened by similarity of appearance (T[S/A]) species
may be found within the project area or in areas potentially
affected by the project:
loggerhead sea turtle (Caretta caretta) - T
green sea turtle (Chelonia mydas) - T
Kemp's ridley sea turtle (Lepidochelys kempii) - E
leatherback sea turtle (Dermochelys coriacea) - E
hawksbill sea turtle (Eretmochelys imbricata) - E
shortnose sturgeon (Acipenser brevirostrum) - E
West Indian manatee (Trichechus manatus) - E
piping plover (Charadrius melodus) - T
14
American alligator (Alligator mississippiensis) - T
Northern right whale (Balaena glacialis) - E
humpback whale (Megaptera novaeanglia) - E
seabeach amaranth (Amaranthus pumilus) - T
The most common sea turtle in the study area is the loggerhead
which nests on ocean beaches adjacent to the project area.
The ocean beaches at Bald Head Island are the most highly used
beaches for loggerhead nesting in North Carolina. Over 100
nests are recorded each year and as many as 193 nests have
occurred in one year (Dr. William David Webster, University of
North Carolina at Wilmington, personal communication, May,
1992). This species is found within offshore and inshore
coastal waters including sounds between April through
November.
Another Federally-listed threatened sea turtle, the green sea
turtle, has nested on Bald Head Island, although this was an
isolated occurrence (Kelly Cook, Bald Head Island Nature
Conservancy, June, 1992). On June 17, 1992 a Kemp's ridley
sea turtle, an endangered species, nested on Long Beach, the
southern section of Oak Island, just to the south of the study
site. This positive identification is the first record of the
species nesting in North Carolina. However, two other
descriptions of sea turtles nesting in North Carolina during
the 1992 season fit the description of the Kemp's ridley
turtles (Therese Conant, Sea Turtle Coordinator, N.C. Wildlife
Resources Commission, personal communication, August, 1992).
Loggerhead, Kemp's ridley, green, leatherback and hawksbill
sea turtles may occur within the nearshore waters of the
project area. However, the hawksbill sea turtle is generally
not seen north of Florida, but limited sightings of this
species off the North Carolina coast have occurred.
Northern right whales and humpback whales may also be found in
the nearshore waters within the boundaries of the project.
Both species are Federally-listed as endangered. The Northern
right whale is in serious danger of extinction within the
foreseeable future. The population has not increased
significantly in size since commercial harvests ended over 50
years ago (USMMS 1990). Northern right whales migrate off the
coast of North Carolina during spring and fall. Most
nearshore sightings have been between January through May, but
they may be present at other times of the year. Generally,
sightings occur very near the shoreline. Humpback whales are
believed to migrate offshore North Carolina during spring
migration, April and May, and fall migration, September
through December. They are generally found in waters between
15
66 and 240 feet deep, out of the limits of this project (USMMS
1990).
Shortnose sturgeon occur in the Cape Fear River. However,
their presence within the ocean bar channel area is unknown.
Adults may migrate through the area as they move from ocean to
fresh water areas for spawning and as they return to the
ocean, but this has not been documented (Steve Ross,
University of North Carolina at Wilmington, Center for Marine
Science Research, personal communication, August, 1992). It
is possible that the Cape Fear River population does not
actually make ocean runs but just migrates from upriver sites
to the lower reaches of the estuary between spawning periods
(Dr. Mary Moser, personal communication, August, 1992). This
is known to occur in some northern populations of sturgeon.
Shortnose sturgeon begin to migrate up the Cape Fear River
during late December, but it is not known whether this
population is returning from the ocean and is thus passing
through the ocean.bar channel area or if the population
remains year round in the estuary. The time period during
which channel deepening is least likely to result in impacts
to the sturgeon is difficult to determine based on the limited
data available. According to Dr. Moser, late August through
September would probably be the best time for work assuming
the sturgeon moves from the ocean to the estuary (Dr. Mary
Moser, personal communication, August, 1992).
The NMFS has responsibility for Federally-listed marine and
anadromous species, including sea turtles when "in the water,"
the shortnose sturgeon, and marine mammals, with the exception
of the West Indian manatee. The NMFS should be contacted
regarding any endangered and threatened marine or anadromous
species which may be affected by the project. Their address
is:
National Marine Fisheries Service
U.S. Department of Commerce
9450 Koger Boulevard
Duval Building
St. Petersburg, Florida 33702
The West Indian manatee, also known as the Florida manatee, is
a Federally-listed endangered species. Although this species'
principle stronghold in the United States is Florida, it
occasionally makes its way into the coastal waters of North
Carolina (Webster et al. 1985). Generally, manatees remain
along the coastal waters of the Florida peninsula during the
winter and disperse more during the summer months, some moving
up along the Atlantic Coast to North Carolina. Observations
of manatees from within the Cape Fear River and surrounding
16
waters are generally reported every year during the summer
months. Numbers of sightings are very low, but they do occur
within the Cape Fear River on a regular basis during warm
months (David Webster, University of North Carolina at
Wilmington, personal communication, May 1993, and Mary Clark,
North Carolina Museum of Natural History, personal
communication, May, 1993).
The piping plover is a Federally-listed threatened species.
This species' decline,is attributed to increased development
and recreational activities on beaches. Vehicle and foot
traffic on beaches can directly crush eggs and chicks or
indirectly lower productivity by disrupting territorial
establishment and breeding behavior. Increased development of
beach areas also has resulted in an increase in plover chick
and egg predators, such as gulls and raccoons.
Piping plovers prefer upper edges of overwash areas at inlets
or large open unvegetated beaches for nesting. While there
has been no documentation of piping plovers nesting on Bald
Head Island, suitable piping plover habitat may exist on the
island. Three piping plover nests were observed on Holden
Beach at the western end of Oak Island during the 1992 season,
but none of these nests were successful. Piping plovers have
also used Oak Island during winter and during migration (Tom
Henson, N.C. Wildlife Resources Commission, personal
communication, August, 1992).
Seabeach amaranth, a Federally-listed threatened species, is
an annual plant which grows on barrier islands primarily on
overwash flats on accreting ends. However, it can sometimes
be found on middle portions of islands on upper strands of
noneroding beaches. It is a dune building pioneer species and
is usually found high on the beach in front of the foredune.
This plant has been extirpated from 75 percent of its
historical range, and North Carolina is considered seabeach
amaranth's present stronghold (Weakley and Bucher 1992).
Candidate species are those which, although not now listed or
officially proposed for listing as endangered or threatened,
are under status review by the Service. These "Candidate" (Cl
and C2) species are not legally protected under the Act and
are not subject to any of its provisions, including Section 7,
until they are formally proposed or listed as threatened or
endangered. These species may be listed in the future at
which time they will be protected by the Act. In the
meantime, we would appreciate anything you might do for them.
The only candidate species which may occur within areas
covered by this project is dune blue curls (Trichostema
17
dichotomum). Dune blue curls utilizes high dunes and
grasslands behind primary dunes.
FUTURE OF PROJECT AREA WITHOUT THE PROJECT
It is necessary to distinguish between changes in the fish and
wildlife resources which will likely occur without the project
and those expected as a result of the project. To accomplish
this, a discussion of anticipated future conditions of fish
and wildlife resources without the project, is presented.
Periodic maintenance of the ocean Bar channel and other
channels of Wilmington Harbor will continue to temporarily and
periodically increase turbidity in the waters, resulting in
physiological stress and mortality to some aquatic species,
and will continue to periodically disturb the benthos of
channel bottoms. However, some large shipping lines may
discontinue their use of Wilmington Harbor if the ocean bar
channel is not deepened. If this happens, there will be a
reduction in the number of ships producing large wakes in the
Cape Fear River and possibly a reduction in shoreline erosion
along the river including shorelines of colonial waterbird
nesting islands. If ship use of Wilmington Harbor reduces
drastically, then the frequency of maintenance dredging of
portions of the Harbor may be reduced, and turbidity and
physiological stress to aquatic organisms in the River
resulting from dredging will occur less often.
Further deepening of Wilmington Harbor channels from the ocean
bar to a point on the Northeast Cape Fear River approximately
1.7 miles upstream of the Hilton Railroad Bridge above
Wilmington is being considered in the Wilmington Harbor Cape
Fear - Northeast Cape Fear Rivers Comprehensive Study (USACOE
1992). The Comprehensive Study will investigate deepening of
the ocean bar channel beyond that proposed in the current
project. Thus, it is possible that even if the current
project is not carried out, the ocean bar channel may be
deepened as a part of the Comprehensive Study. If the ocean
bar is not deepened as part of the Comprehensive Study, then
deepening of other channels will not be necessary since the
ocean bar channel is the most seaward channel and serves as
the entrance to the Harbor.
Development and alteration of terrestrial and wetland
communities on mainland and barrier islands in the area is
occurring and is expected to continue. Golf courses on Bald
18
Head Island will continue to be managed and landscaped and as
a result of these activities, nonpoint source runoff may
result in further declines in water quality of adjacent
waters. The study area is expected to remain high value
habitat for estuarine dependent fishery species which will
continue to use local waters for feeding, spawning, and as
nursery habitat. Marine mammals and sea turtles are expected
to continue to use the study waters. Colonial nesting
waterbird islands in the area will continue to support nesting
bird populations as long as management of the islands
continues, including disposal of dredged material when needed.
Past Wilmington Harbor Channel construction activities and the
creation of Snows Cut connecting the Atlantic Intracoastal
Waterway with the Cape Fear River, along with continued sea
level rise, have resulted in increased tidal amplitudes and
saltwater intrusion up the Cape Fear River. The estuary's
freshwater wooded swamps are being converted into salt,
brackish and oligohaline tidal marshes. Dredging activities
within the Cape Fear River, such as the widening of a turning
basin and the construction of a passing lane, will likely
result in further intrusion of saltwater into the upper
reaches of Wilmington Harbor.
Beach nourishment occurred on Bald Head Island during 1991,
and this activity may continue annually or less frequently in
the future. A 50-year plan for annual beach nourishment has
been prepared by the Corps. However, annual approval will be
required. Beach erosion is serious on Bald Head Island and
with sea level rising, with the continued use of the
Wilmington Harbor channels by large ships, and with
maintenance dredging of the Wilmington Harbor channels
occurring, erosion is expected to continue and to increase in
the future. Sea turtle habitat and potential piping plover
habitat may be reduced as a result. Although certain areas
of Bald Head Island may experience severe erosion, the island
is expected to remain very important nesting habitat for the
loggerhead sea turtle.
DESCRIPTION OF ALTERNATIVES
The proposed project involves deepening the channel so that a
40-foot depth is maintained throughout the year along the
entire channel. The 1991 Reevaluation Report (USACOE 1991b)
presented several alternatives which varied in the amount of
required overdepth. At that time, the Corps believed that a
considerable amount of overdepth would be required in order to
limit maintenance dredging to once a year due to rapid
19
shoaling of the channel. Alternatives considered for the
amount of required overdepth were four, three and two feet.
However, after further analysis, the Corps believes that
maintenance dredging will be necessary only once a year if the
project involves one foot of required overdepth for areas
underlain by rock. Thus, other overdepth alternatives are no
longer being evaluated (John Meshaw, Biologist, Wilmington
District Corps, personal communication, April, 1993).
The following information is taken from an outline of the
project description received from the Corps in April 1993
(USACOE 1993a). The project involves lengthening the channel
from 24,000 feet to 30,500 feet and deepening the entire
channel to 40 feet plus 1 foot required overdepth in areas
with underlying rock plus an additional 2 feet of allowable
overdepth to allow for dredging inconsistencies. This means
the actual depth of the channel would be between 42 to 43
feet. The plan would involve an extension of the channel into
the Atlantic Ocean to a point where natural depths are equal
to the channel depth. The total bottom width of the channel
would not change from 500 feet, and the side slope of the
channel would remain 1 vertical to 5 horizontal (1:5) in areas
of unconsolidated soft material. Side slopes in rock areas
would be steeper (approximately 1:3) in order to limit the
amount of rock requiring removal. The proposed deepening and
lengthening of the ocean bar channel would increase the
footprint of the channel from 306 acres to 393 acres, a
difference of 87 acres.
Initial deepening will require the removal of approximately
830,000 cubic yards (cy) of limestone rock and approximately
100,000 cy of sand, silt, clay, and shell fragments over that
removed during maintenance dredging. The sand would be
removed by hydraulic pipeline dredge, and the rock would be
removed with a rock cutterhead on a hydraulic pipeline dredge
and/or will require blasting. 'A scow may be used to carry the
material removed with a pipeline dredge to its destination.
If blasting is necessary, a bucket and barge dredging system
will remove the rock after blasting and dispose of the
material.
According to a project descriptions received from the Corps on
April 22, 1993, and May 20, 1993, blasting will be limited to
rock which could not be dredged. It is estimated that less
than two percent of the total rock or less than 14,000 cubic
yards is non-dredgeable. If blasting is required, numerous
blast holes will be drilled per day, and explosives will be
placed in the holes with crushed stone or other material
filling the hole to the top. This procedure is known as
20
"stemming the blast." This procedure should reduce the impact
to the surrounding aquatic environment while increasing the
fragmentation of the rock (USACOE 1993b, and 1993c).
During one day, several rows of holes would be drilled and
filled with explosives and 25 millisecond delays would be
incorporated between rows. Using delays reduces each
detonation into several smaller explosions, and the resulting
pressure is related to the size of the charge in each row of
holes rather than the cumulative charge in all holes. This
should reduce the lethal range compared to that which would
result if the charges in each hole were connected (John
Meshaw, Biologist, Wilmington District Corps, personal
communication, April, 1993).
The Corps has estimated that to blast the 14,000 cubic yards
of rock, a maximum of 60 blasts would be required. This
estimation is based on the assumption that the maximum number
of holes per day will be drilled and one blast would occur for
all of the holes. The channel deepening would be contracted
out, and certain aspects of any blasting, such as the type of
explosives used, would be the decision of the contractor.
However, water gel explosives are typically used in this type
of work. According to the Corps, the contract which goes out
for bid would state that limited blasting would be allowed and
if blasting occurs, stemming of at least the top foot of the
blast hole would be required, instantaneous delays would be
used between rows, and a limited number of blasts would be
allowed.
The contract would be for the overall deepening of the ocean
bar channel and because blasting is generally much more
expensive than dredging, the contractor would probably benefit
economically by dredging as much of the rock as is possible,
keeping blasting to a minimum. Thus, in theory, the
contractor should dredge rather than blast, if possible (John
Meshaw, Biologist, Wilmington District Corps, personal
communication, May, 1993). Rock is encountered beginning
about 12,500 feet seaward of the entrance to the Cape Fear
River. Therefore, blasting would only potentially be
necessary in the area 2 miles or further from the shoreline
(John Meshaw, personal communication, April 1993).
The majority of the material removed will be dumped at the
Wilmington Harbor Ocean Dredged Material Disposal Site (ODMDS)
located about four miles east of the channel. The material
will be placed at the eastern section of the ODMDS, as far
away from the navigation channel as possible (USACOE 1993c).
Some of the rock may be used to create artificial reef
21
habitat. The NCDMF Artificial Reef Program and the National
Marine Fisheries Service were consulted regarding the
possibility of using rock removed from the channel for
creation of an artificial reef. However, an experimental
removal of some of the rock during 1992 with a cutterhead
pipeline dredge, revealed that the predominant size of the
rock removed by a cutterhead dredge was about the size of golf
balls. Concern was expressed by resource agencies that the
rock removed from the channel may be too small to stack up
properly and provide adequate interstitial spaces needed for a
successful reef. In addition, the rock-would have been mixed
with overlying sediments making it even-less suitable.
Therefore, rock removed by cutterhead pipeline dredge will not
be used as artificial reef material. Blasting, however,
fractures rock and should produce larger pieces of material
than will dredging. If blasting occurs, approximately 14,000
cubic yards of rock may be produced and if it is of
appropriate size, it may be used for artificial reef creation
(John Meshaw, Biologist, Wilmington District Corps, personal
communication, May, 1993). Reef sites which are part of the
NCDMF Artificial Reef Program would be used. The NCDMF is
considering the Reef Sites AR-445, located approximately 9.8
miles southwest of the entrance channel buoy, or AR-420,
located about 2.9 miles northwest of the entrance channel buoy
(USACOE 1993c).
Project maintenance would involve annual dredging increases of
approximately 128,000 cy of sand over the amount presently
dredged during maintenance activities (USACOE 1993b).
According to the Corps' project description, project
construction would occur between July 1994 and May 1995.
Drilling and blasting may occur within the last 90 days of
this time period, or approximately March through May, 1995
(USACOE 1993b).
DESCRIPTION OF IMPACTS
Impacts Related to Dredging
The Wilmington Harbor Ocean Bar channel deepening will result
in the disturbance of a 6,500 foot by 500 foot section or
about 75 acres of previously undisturbed ocean bottom.
Approximately 930,000 cubic yards of additional material will
be excavated during the deepening project. Of this,
approximately 830,000 cubic yards is rock and about 100,300
cubic yards is comprised of sand, silt, clay and a small
amount of shell. Removal of rock using a cutterhead dredge
will result in mortality of benthos, plankton, and nekton
unable to escape the dredge. Larvae are particularly
22
vulnerable because many are flowing freely with the currents
and are likely to be sucked up by the dredge. Although some
adults would also be swept up by the dredge, most should be
able to avoid it. The most critical time period for larval
fish moving through the estuary is between January through
April.
Impacts Related to Blasting
Blasting will result in the mortality of fish, marine mammals
and sea turtles and other life within a certain radius of the
explosion. The lethal range will depend on the type of
explosives used and the methods of blasting. These have not
been identified by the Corps at this time.
Linton et al. (1985) summarize past studies on the effects of
blasting on marine organisms. Past studies indicate that
different species and different life stages react differently
to shock pressures. Eggs, larvae, juveniles, and adult
organisms with air bladders tend to be most susceptible to
explosives. Damage is directly proportional to the pressure
produced by the explosion and the time over which it is
produced. For example, a high velocity explosion produces
high pressure over a short duration. The rapid rise and fall
in pressure causes swim bladders to rupture because they do
not have time to adjust. Linton et al. (1985) state that
generally, high velocity explosions producing a peak pressure
of 40 pounds per square inch will kill some fish within a
certain radius of the explosion and those producing a peak
pressure above 70 psi will kill all fish within a certain
radius of the blast site. However, with low velocity
explosives, such as black powder, pressure rises and falls
slower and fish may withstand pressures over 70 psi.
Linton et al. (1985) cite a study by Fitch and Young (1948)
who found that species with thick-walled swim bladders appear
to be more resilient to 10 to 160 pounds of high explosives
than those with thin-walled swim bladders.
Linton et al.'s (1985) survey of the past literature also
revealed that the effects that water depth, burying charges in
sediment, and methods used to move fish and other organisms
away from blasts sites, have on the lethal range and organism
mortality are variable. Some studies indicate that explosives
at greater depths increase the potential to kill fish, but,
other studies show no relationship between water depth and the
lethal potential. It is generally thought that embedding
shots reduces the potential to kill fish. However, some
studies have shown that embedded shots are just as lethal as
23
others. Hubbs and Rechnitzer (1952) report that charges
killed fish even when explosives were buried by many feet in
sediments. Rasmussen (1967) found that burying charges in the
seabed generally reduced their lethal effect. The extent of
the lethal range may also vary with different ocean floor
configurations. Methods used to drive away organisms from
areas to be exploded have also shown varying results. Based
on their literature review, Linton et al. (1985) state that
warning shots are probably not very successful in dispersing
fish away from blast sites. However, as part of a tunnel
construction project in Boston Harbor, sound was used to drive
fish away from blast sites with considerable success (EA
Engineering, Science and Technology et al. 1992).
Coker and Hollis (1950) (cited by Linton et al. 1985) found
that for blasts using high explosives with charges ranging
from 250 to 1,200 pounds, the lethal range did not exceed 600
feet and was on average approximately 300 feet out from the
blast site.
For various weights of high velocity explosives, Linton et al.
(1985) recommend a minimum distance away from any reefs,
schools of fish and other important aquatic resources of
approximately 1000 feet.
Blasting may result in the mortality of northern right whales,
short-nosed sturgeon, and sea turtles as well as anadromous
fish and larvae of estuarine dependent species. It will be
very difficult to assess the species and the number of
organisms lost as a result of blasting.
Blasting and dredging also will likely result in increased
turbidities in the immediate vicinity,.potentially clogging
the gills of fish and invertebrates. Turbidity levels will
depend on the amount of fine materials being resuspended.
Potential impacts to migrating whales, sea turtles, fish, and
invertebrates, especially larvae, can be minimized if
deepening activities occur during periods when these organisms
are not utilizing the study area habitat or when their numbers
are low. Blasting will especially require seasonal
restrictions due to the inability of organisms to escape
blasting effects. Finding a suitable time period for blasting
will be difficult because the critical time periods for
whales, sea turtles, larval fish and anadromous species
differ. The most critical time period for estuarine dependent
larvae passing through the area as they move into the estuary
is between January and April. Whales may be present during
spring migration, and fall migration. They have been observed
24
.
most often during March and April. One October sighting
indicates that they may migrate farther offshore during the
fall. Sea turtles are generally found in the nearshore and
inshore waters between April through November. Shortnose
sturgeon from the Cape Fear River may pass through the ocean
bar area during migration. However, it is unknown whether or
not that population of shortnose sturgeon makes an ocean run
and thus passes through the ocean bar channel. Assuming that
shortnose sturgeon do use the ocean bar area, the period least
likely to impact this fish is probably between mid-August
through September (Mary Moser, University of North Carolina at
Wilmington, Center for Marine Science Research, personal
communication, April, 1993). As mentioned earlier, the
National Marine Fisheries Service is responsible for
Federally-listed endangered and threatened marine and
anadromous species. Monitoring of the area being blasted will
be necessary before and after blasting activities.
Impacts Related to the Deepening of the Channel
Deepening the ocean bar channel may increase the tidal
amplitude moving into the Cape Fear River and increase
saltwater intrusion farther upstream. This may result in the
additional conversion of forested wetlands into oligohaline
marsh and more saline environments. Such impacts are
difficult to attribute to particular harbor activities, and
the extent of such habitat conversions is especially difficult
to predict. Habitat conversion of forested wetlands into
oligohaline and salt marsh will benefit fauna adapted to marsh
and adversely affect species depending on forested wetlands,
such as black bear (Ursus americanus), wood duck and songbirds
like the prothonotary warbler. Further saltwater intrusion
will increase the ranges of marine fish and invertebrates,
such as pink shrimp, farther upstream and prevent the movement
of freshwater species downstream.
Deepening of the ocean bar channel also may result in
additional erosion problems to adjacent barrier islands. Deep
channels trap sediments moving through littoral transport
along the coast, and the result may be a starvation of sands
to adjacent beaches, especially if the material removed from
the channel during initial and maintenance dredging is
deposited outside of the littoral system. These impacts also
are very difficult to predict, especially without a detailed
understanding of the sediment budget in the immediate area.
Bald Head Island has been experiencing serious erosion
especially along its southern beach for two decades. As
requested by the village of Bald Head Island, the Corps
25
completed a Reconnaissance Report in 1989 on Bald Head Island
which determined that there was no direct relationship between
the dredging of the Wilmington Harbor ocean bar channel and
the severe erosion occurring on Bald Head Island. However,
dredging of navigation channels with offshore disposal has
been linked to erosion of adjacent shorelines. The removal of
material from Oregon Inlet with deposition offshore has been
directly linked to the erosion of adjacent Pea Island. For
every cubic yard of sediment dredged from Oregon Inlet and
removed from the littoral system, an equal amount of erosion
occurs on adjacent beaches (Inman et al. 1991).
The Corps' Wilmington Harbor - Bald Head Island Evaluation
Report, dated June 1990, investigated the possibility of
placing material dredged from maintenance dredging of
Wilmington Harbor channels on Bald Head Island as an erosion
control method. This report determined that the village of
Bald Head Island is eligible for a 50-50 cost sharing for the
added cost of placing compatible material on the beach of Bald
Head rather than placing it at the ODMDS several miles
offshore.
Impacts Related to Disposal of Material Removed from the
Channel
• A potential positive use of the rock after removal from the
channel would be to use it for creation of artificial reef
habitat, if the rock is of suitable size to stack, if fine
materials are not dumped with the rock, and if the rock is not
contaminated (Steve Murphy, North Carolina Division of Marine
Fisheries, Artificial Reef Coordinator, personal
communication, August, 1992). If silt is deposited along with
the rock and the rock is contaminated, then placing the
material at an existing artificial reef site could result in
adverse impacts to fish already utilizing the reef.
Conversely, if of acceptable quality, it could provide
productive fishery habitat. As indicated earlier, only rock
removed by blasting would potentially be used for artificial
reef creation since rock removed by dredge will probably be
unsuitable.
If material is placed at the Wilmington Harbor ODMDS, benthos
will be buried and turbidity may temporarily increase, but
because the area is already disturbed, impacts would be
minimal. If rock is placed at the ODMDS, then the disposal
site may reach its capacity more quickly requiring a new site
for future dredged material disposal.
26
A potential beneficial use of sand removed from the channel
would be beach nourishment of adjacent barrier island beaches,
Bald Head Island or Oak Island, provided the sand is
compatible. Disposal of the material at the ODMDS would
remove material from the littoral system and may accelerate
erosion on Bald Head Island.or Oak Island. Material from
maintenance dredging of the channel has been deposited at the
ODMDS in the past, and this activity may have affected the
shoreline along Bald Head Island. Further deepening of the
channel may exacerbate erosion on the island because
additional sand may become trapped-in the deeper channel and
removed from the littoral zone as it is dumped at the ODMDS.
Use of sandy material for beach nourishment of Bald Head
Island or Oak Island would keep material within the littoral
zone. Beach nourishment projects are becoming increasing
popular in North Carolina communities and the identification
of suitable borrow material is becoming a major problem. When
possible, compatible material from inlets should be used for
this purpose. However, the Corps has indicated the material
which will be removed from the channel does not contain a
sufficient amount of beach quality sand to make beach
nourishment a viable alternative.
COMPARISON OF ALTERNATIVES
Removal of the rock underlying the channel by blasting with
explosives would result in more severe adverse impacts to fish
and wildlife resources than would the use of a cutterhead
dredge. Blasting would kill all organisms within a certain
radius of the explosions, and the extent of blasting-caused
mortality would be difficult to quantify. Blasting could
potentially kill whales, sea turtles, adult fish and
invertebrates, as well as juveniles and larvae. Mortality
caused by the use of a cutterhead dredge would be more
localized, and most adult organisms would be able to escape
the dredge. Both processes would result in turbidity plumes,
depending on the amount of fine materials being resuspended.
Possible rock disposal alternatives being considered are the
use of some of the rock for creation of artificial reef
habitat and the dumping of the rock at the Wilmington Harbor
ODMDS. Utilizing rock from the channel as artificial reef
habitat would enhance fishery resources if the rock is of
suitable size to stack, is not contaminated and if silts are
not deposited with the rock. Only rock removed by blasting is
expected to be of appropriate size for reef construction.
Artificial reefs provide substrate for marine organisms to
27
attach and grow, provide excellent foraging habitat, and
become refuges for fish and other organisms. Dumping the rock
at the ODMDS might create hard bottom at the site, but this
would not be a suitable reef location due to future dumping of
dredged material at the site. The ODMDS also may contain
higher levels of pollutants than other areas, making the ODMDS
less suitable as a place for fish to congregate.
FISH AND WILDLIFE CONSERVATION MEASURES
Fish and wildlife conservation measures-include: 1)
mitigation; and 2) enhancement. Mitigation, as defined by the
council of Environmental Quality and adopted by the Service in
its Mitigation Policy (Federal Register 46[15] 1656-1662,
January 23, 1981) includes: 1) avoiding the impact altogether
by not taking a certain action or parts of an action; 2)
minimizing impacts by limiting the degree or magnitude of the
action and its implementation; 3) rectifying the impact by
repairing, rehabilitating, or restoring the affected
environment; 4) reducing or eliminating the impact over time
by preservation and maintenance operations during the life of
the project; and 5) compensating for the impact by replacing
or providing substitute resources or environments. This five-
action sequence should be viewed as the proper order for
formulating mitigation measures.
If a cutterhead dredge can be used to cut through the rock
underlying the channel, then many of the major potential
impacts to fish and wildlife resources can be avoided and
minimized. The Service believes the project should be
conducted without the use of blasting if at all possible.
Blasting should be used only as a last resort. If blasting
must occur, then a strict time frame should be developed which
takes into account the presence of endangered and threatened
species such as sea turtles, right whales and shortnose
sturgeon. The use of the channel by anadromous species and
estuarine dependent species also should be considered in
developing the blasting window. Considering the time periods
at which shortnose sturgeon, sea turtles, northern right
whales, anadromous species and estuarine dependent fish and
invertebrate larvae utilize the study area, there is really no
suitable time period for conducting blasting activities. At
all times of the year, blasting may potentially affect one or
another species of concern. The National Marine Fisheries
Service should be contacted regarding Federally-listed marine
and anadromous species.
It may be possible to use blasting during critical time
periods if other measures are undertaken which will ensure
28
V
that mortality of endangered and threatened species is
prevented and mortality of other species is minimized. For
example, in Florida, when blasting activities have occurred,
the Service has required that a manatee watch be conducted
with at least two qualified people observing from watercraft,
aircraft or a high vantage point for at least one half-hour
immediately before and after detonation in a defined circular
radius around the blast zone. The defined circular radius is
based on the weight of the explosive charge in pounds. The
following is the formula used in Florida for determining the
lethal zone for manatees:
r = 260 31V
where
r = radius of the danger zone in feet
w = weight of the explosive charge in pounds (tetryl or
TNT)
Blasting activities implementing this procedure have not
resulted in injury to or mortality of manatees (Don Palmer,
Biologist, U.S. Fish and Wildlife Service, Jacksonville Field
office, personal communication, April, 1993).
Blasting operations associated with construction of a tunnel
in Boston Harbor involved the use of hydroacoustic resonance
to evaluate the distribution of migrating anadromous fish
relative to the areas where blasting occurred. Plans included
mounting side-scanning transducers on the drill barge and on a
boat working at the edge of the blast zone to monitor schools
of river herring within an approximate 500-foot radius of the
blast site. Periodic net sampling using trawls and gill nets
was used to document the species composition of the
populations detected with the hydroacoustic equipment. Plans
also called for visual monitoring by scientists on a boat, as
well as a mid-water trawl immediately following blasting
events to look for disoriented, injured or dead fish and to
collect and identify any dead or injured fish. Project plans
for the Boston Harbor blasting project also called for the use
of sound to disperse fish away from the blast zone (EA
Engineering, Science and Technology et al. 1992). As a result
of 30 blasts conducted between May 11, 1992 and May 31, 1992
which incorporated the fish deterrence protocol, only 9
dead/stunned river herring were recovered. Terns and gulls
were observed in the blast zone picking up small fish on
several days, but numbers of dead/injured fish appeared to be
very low (EA Engineering, Science and Technology 1992). The
Corps has contacted the Project Manager of Sonalysts. Inc. and
he indicated that the sound deterrence methodology has been
developed and has shown considerable success in other
29
projects; however, the methodology involves using particular
sound emissions at specific frequencies for specific fish.
Currently the details have been worked out for only a few
species - shad, herring and alewives (John Meshaw, Biologist,
Wilmington District Corps, personal communication, May 1993).
Dredging within the channel using a hydraulic cutterhead
pipeline dredge also should involve a dredging window which
takes into account potential impacts to larvae of estuarine
dependent species. If work is avoided during environmentally
sensitive periods of the year, then direct impacts to fish and
wildlife can be avoided or minimized. Larval fish and
invertebrates are most vulnerable to dredging because many
simply move with the currents while adults can swim out of the
dredge path. The most critical time period for larval fish
moving through the estuary is between January through April,
and dredging with a cutterhead pipeline dredge should be
avoided during this time, if possible (Fritz Rhode, N.C.
Division of Marine Fisheries, Wilmington, NC, personal
communication, August, 1992). -
Artificial reef creation would enhance fishery resources and
should be used to partially compensate for unavoidable impacts
to marine resources if suitable rock is produced. As
indicated earlier, only rock removed by blasting is likely to
be suitable reef material.
The saltwater intrusion and habitat conversion which has
occurred and will occur up the Cape Fear River is
attributable, at least partially, to cumulative impacts of
past dredging activities in Wilmington Harbor. The Service
has identified the affected forested wetlands in the area as
Resource Category 2 wetlands and believes the expected future
loss of forested wetlands should involve in-kind habitat
replacement. To do this, the Corps should estimate the
potential losses and replace lost habitat value through
construction of replacement habitats, restoration of
previously altered forested wetlands within the impact areas
to ensure that no net loss of in-kind habitat value occurs.
The Corps should in coordination with the North Carolina
Wildlife Resources Commission, the North Carolina Division of
Coastal Management and the Service, develop and implement a
mitigation plan in response to cumulative salt
intrusion/habitat conversion impacts resulting from past and
present Wilmington Harbor projects.
The potential for the deepening of the channel to accelerate
erosion of nearby beaches may be reduced if sand dredged from
the channel is used for beach nourishment rather than
30
disposing of the material at the ODMDS outside of the littoral
zone.
31
RECOMMENDATIONS
The Service believes the following recommendations are
necessary and should be incorporated into project plans to
minimize the expected adverse impacts to fish and wildlife
resources.
1. The channel deepening contract should state clearly that
blasting should only be used as a last resort after it is
shown and documented that the rock cannot be removed with a
cutterhead dredge. The Corps has stated that they cannot
require the contractor to complete the deepening project
without the use of blasting, even if blasting is not
absolutely necessary; however, the Corps' experimental rock
removal has demonstrated that the rock can probably be removed
through dredging. Therefore to minimize unnecessary adverse
impacts to public trust resources, the Service prefers and
recommends that the project be done by dredging; however we
would consider the use of minimal amounts of blasting if
removal of material with a rock cutterhead dredge is
demonstrated not to be physically possible. In the latter
case, specific additional mitigation measures would be
necessary as addressed in recommendations 2,4,5,6,7,and 8.
2. If blasting is necessary, measures should be implemented to
minimize the lethal range of the blasts. Those measures should
include: drilling holes for the blasts; stemming the blasts;
using as low velocity explosives as is possible without
diminishing effectiveness; using instantaneous delays between
rows of blasts; and keeping the number of blasts per day and
the total number of blasts to a minimum. The Corps' draft
description of project plans stated that these measures will
be included in the contract, and we support efforts in this
regard.
3. Careful time-of-year planning and impact preventative
measures are necessary for deepening activities so as to avoid
or minimize impacts to sea turtles, migratory whales, West
Indian manatees, shortnose sturgeon and other anadromous
species and estuarine dependent larvae. Dredging and blasting
time frames should be developed in coordination with the
Service, the North Carolina Division of Marine Fisheries and
the National Marine Fisheries Service and will be specified in
the final report. The best time for blasting with regard to
estuarine dependent larvae and anadromous species may be the
period November 1 through December 15. The National Marine
Fisheries Service should be contacted regarding the best time
to conduct activities in order to avoid impacts to sea
turtles, marine mammals, and shortnose sturgeon. In order to
32

avoid impacts to the West Indian manatee, blasting activities
should be avoided between May through October.
4. The Corps should determine the expected lethal radius out
from the detonation site for all groups of organisms of
concern, and this information should be used to ensure that
blasting is avoided when large schools of fish are within the
lethal range of the blast site or when endangered or
threatened species are within the lethal range of the blast
site. The lethal range will likely vary based on the type of
explosive used and the measures implemented and will vary for
different species. The Corps should consider requiring the
contractor to use low velocity explosives because pressure
increases are not as rapid as they are when high velocity
explosives are used, and fish are more likely to survive
explosions.
5. If blasting occurs between May through October, surveys
should be made by at least two Service-approved and qualified
observers from aircraft or watercraft, immediately prior to
blasting, to ensure that no West Indian manatees are within
the lethal range of the detonation. If a manatee is present
within the lethal range, blasting should be postponed until
the animal moves by its own will out of the impact zone.
Similar monitoring will probably be necessary for sea turtles,
whales and dolphins. However, the National Marine Fisheries
Service has jurisdiction over these species and the shortnose
sturgeon, and that agency should be contacted regarding
protection of these species.
6. Immediately prior to blasting, the impact zone should be
surveyed by qualified observers aboard a boat equipped with
fish finder echolocators or transducers. If large schools of
fish are located within the lethal range of the blast site,
blasting activities should be avoided until the fish move out
of the lethal range.
7. The Corps should analyze the possibility of using sound as
a fish deterrence in order to disperse fish away from the
blasting zone, should blasting be necessary. This method
developed by Sonalysts, Incorporated, has been successful in
deterring alewives away from blasts during blasting activities
related to tunnel construction in Boston Harbor.
8. A comprehensive post-blasting monitoring plan should be
developed and implemented so that the species and number of
organisms killed by the blasts can be estimated. The
monitoring plan should be developed in coordination with the
Service, the North Carolina Division of Marine Fisheries, and
33
the National Marine Fisheries Service and should involve
surveying the blasting impact area by boat and counting and
identifying dead or wounded organisms which float to the
surface. Although all dead organisms may not float to the
surface immediately, this method should give an indication of
the extent of the impacts to finfish and other organisms.
Other monitoring methods may also be necessary.
9. Although it has been determined that rock dredged from the
channel will likely be too small to be high value artificial
reef material, rock removed by blasting-may be of adequate
size to provide suitable reef habitat. 'Any material of
appropriate size should be tested to ensure it is free of
contaminants and if acceptable quality, should be used as
artificial reef material. Such an effort should be closely
coordinated with the National Marine Fisheries Service and the
North Carolina Division of Marine Fisheries. The Corps should
ensure that all rock rubble created through blasting is
removed from the ocean floor so that it does not destroy
trawling nets.
10. To protect nearby beach habitats, limit the amount of
sand removed from the littoral system by using suitable
material dredged from the channel for beach nourishment of
eroding adjacent beaches, rather than placing high quality
sand offshore at the Ocean Dredged Material Disposal Site.
The Corps should determine the sediment budget of the area and
determine how deepening the channel will affect the sediment
budget.
34

SUMMARY
Of utmost concern to the Service is the potential use of
blasting for removal of rock underneath the channel. Blasting
will result in the mortality of fish and invertebrates
including larvae and potentially of right whales and other
marine mammals, sea turtles, West Indian manatees, and
shortnose sturgeon if they happen to be within a certain
radius of the blasts. Careful time-of-year planning will be
necessary if blasting is used, but it will be very difficult
to avoid impacts to all species of-concern, including
Federally-listed species, due to different critical time
periods at which the species are potentially utilizing the
channel and surrounding waters. Pre-blasting surveys will be
required to ensure that West Indian manatees are not within
the lethal range of the blast site at the time of blasting.
Surveys for other endangered and threatened species may be
required, but the National Marine Fisheries Service has
jurisdiction over other listed species potentially in the
impact area. If blasting is required, post-blasting
monitoring should be implemented so that we get an
understanding of the species and number of organisms killed by
the blasts. Dredging also will result in mortality, of
sessile species and those unable to escape the dredge head.
Seasonal constrictions also will be necessary for dredging
activities in order to minimize impacts to finfish and
invertebrate larvae.
Although it appears that rock removed by dredging will not be
of an appropriate size to provide suitable reef habitat, the
Corps has indicated that if blasting occurs, rock removed may
be large enough to be used in artificial reef construction.
We support the Corps' plans to make this rock available to the
North Carolina Division of Marine Fisheries for artificial
reef construction, but the Service recommends any such plan be
closely coordinated with the National Marine Fisheries Service
and the North Carolina Division of Marine Fisheries.
Further study is necessary to assess the
Wilmington Harbor dredging activities to
intrusion up the Cape Fear River. An ap]
plan should be developed and implemented
loss and conversion of forested wetlands
Wilmington Harbor dredging activities.
potential for
increase saltwater
?ropriate mitigation
for the cumulative
resulting from all
Sand removed from the channel during initial construction or
maintenance dredging, if compatible with natural beach sand,
should be used for beach nourishment of adjacent beaches
rather than removing the material from the littoral zone.
35
r.
LITERATURE CITED
American Fisheries Society. 1980. A List of Common and
Scientific Names of Fishes from the United States and
Canada. 4th ed. American Fisheries Society, Washington,
DC. 174 pp.
Banks, R.C., R.W. McDiarmid, and A.L. Gardner. (eds.) 1987.
Checklist of vertebrates of the United States, the U.S.
territories, and Canada. U.S. Fish and Wildlife Service,
Resource Publication 166. 79 pp. _
Coker, C.M. and E.H. Hollis. 1950. Fish mortality caused by
a series of heavy explosions in Chesapeake Bay. Journal of
Wildlife Management. 14(4):435-444.
EA Engineering, Science and Technology. 1992. Fish monitoring
data for 21 blasts conducted between May 11, 1992 and May
17, 1992 and for 9 blasts conducted between May 25 and May
30 for the Central Artery Tunnel Project. EA Engineering,
Science and Technology, Sharon, Massachusetts.
EA Engineering, Science and Technology, Barnes-Williams
Environmental Consultants, and Sonalysts, Inc. 1992a.
Final Draft - Monitoring Program for Anadromous Fish during
Blasting Operations associated with the Central
Artery/Tunnel Project. EA Engineering, Science and
Technology, Sharon, Massachusetts.
Fitch, J.E. and P.H. Young. 1948. Use and effect of
explosives in California coastal waters. California Fish
and Game. 34(2):53-73.
Hackney, C.T. and G.F. Yelverton. 1990. Effects of human
activities and sea level rise on wetland ecosystems in the
Cape Fear River Estuary, North Carolina, USA. Pp 55-61 In
D.F. Whigham, R.E. Good, and J. Kvet (eds). Wetland
Ecology and Management: Case Studies. Kluwer Academic
Publishers, the Netherlands.
Hubbs, C. L. and A.B. Rechnitzer. 1952. Report on
experiments designed to determine effects of underwater
explosives on fish life. California Fish and Game.
38(3):333-366.
Inman, D.L., R.G. Dean, R. Dolan, J. Schmertmann, and D.G.
Aubrey. 1989. Protection of Bonner Bridge, Oregon Inlet,
North Carolina. Report prepared for Fish and Wildlife
36

t
Service and National Park Service, U.S. Department of the
Interior. 28 pp. + App.
Linton, T.L., N. Hall, D. Labomascus and A. Landry. 1985.
The Effects of Seismic Sounds on Marine organisms: an
Annotated Bibliography and Literature Review. Texas A & M
University, Galveston, Texas. 67 pp.
National Marine Fisheries Service. 1993. Marine Recreational
Fisherman Statistics Survey Data. National Marine
Fisheries Service, Southeastern-Fisheries Science Center,
Beaufort, North Carolina.
North Carolina Coastal Resources Commission. 1990. Final
Report of the Maritime Forest Working Group. North
Carolina Department of Environment, Health and Natural
Resources, Division of Coastal Management, Raleigh, N.C. 31
pp. + App.
Parnell, J.F. and M.A. Shields. 1990. Management of North
Carolina's Colonial Waterbirds. National Oceanic and
Atmospheric Administration. UNC Seagrant Publication
Number UNC-SG-90-03. 169 pp.
Radford, A.E., H.A. Ahles, and C.R. Bell. 1968. Manual of
• the Vascular Flora of the Carolinas. University of North
Carolina Press, Chapel Hill, North Carolina. 1183 pp.
Rasmussen, B. 1967. The effect of underwater explosions on
marine life. Bergen, Norway. 17p. In Falk, M.R. and M.J.
Lawrence. 1973. Seismic exploration: its nature and
effect on fish. CEN T-73-9.
Schwartz, F.J., P. Perschbacher, M. Mcadams, L. Davidson, K.
Sandoy, C. Simpson, J. Duncan and D. Mason. 1979. An
Ecological Study of Fishes and Invertebrate Macrofauna
Utilizing the Cape Fear River Estuary, Carolina Beach Inlet
and Adjacent Atlantic Ocean, Summary Report 1973 - 1977.
Institute of Marine Science, University of North Carolina,
Morehead City, North Carolina, 568 pp.
U.S. Minerals Management Service. 1990. Final Environmental
Report on Proposed Exploratory Drilling Offshore North
Carolina. Volume I. Minerals Management Service, Atlantic
OCS Region, Herndon, VA. 669 pp.
U.S. Army Corps of Engineers. 1988. Draft Reconnaissance
Report. Wilmington Harbor Passing Lane. Wilmington
District, Corps of Engineers, Wilmington, NC. 149 pp.
37

1989a. Reconnaissance Level Study, Wilmington
Harbor - Turns and Bends. Wilmington District, Corps of
Engineers, Wilmington, NC. 37 pp + App-
. 1989b. Final Environmental Impact Statement for
Long-Term Maintenance of Wilmington Harbor, North Carolina.
Wilmington District, U.S. Army Corps of Engineers,
Wilmington, NC. 100 pp + App.
1990a. Draft Feasibility Study Wilmington
Harbor Turns and Bends. Wilmington District, Corps of
Engineers, Wilmington, NC. 14 pp + App.
1990b. Final Supplement to the Final
Environmental Impact Statement. Wilmington Harbor
Northeast Cape Fear River. Wilmington District, Corps of
Engineers, Wilmington, NC. 106 pp + App.
1990c. Wilmington Harbor - Bald Head Island
Evaluation Report. Wilmington District, Corps of
Engineers, Wilmington, NC. 44 pp + App.
1991a. Environmental Assessment and Finding of
No Significant Impact for Maintenance Dredging in
Wilmington Harbor Ocean Bar Channels. Wilmington District,
U.S. Army Corps of Engineers, Wilmington, NC. 8 pp + App.
1991b. Final Reevaluation Report - Wilmington
Harbor Ocean Bar Channel Deepening. Wilmington District,
U.S. Army Corps of Engineers, Wilmington, NC. 23 pp + App.
1992. Reconnaissance Report on Improvement of
Navigation Cape-Fear - Northeast Cape Fear Rivers
Wilmington Harbor, North Carolina. Wilmington District,
U.S. Army Corps of Engineers, Wilmington, N.C. 11 pp + App.
1993a. Environmental Assessment and Finding of
No Significant Impact (EA/FONSI) - Project Modification and
Mitigation Plan Wilmington Harbor - Northeast Cape Fear
River, New Hanover and Brunswick Counties, North Carolina.
Wilmington District, Wilmington, North Carolina.
. 1993b. Draft Project Description, Wilmington
Harbor Ocean Bar, April, 1993. Wilmington District, U.S.
Army Corps of Engineers, Wilmington, N.C. 1 p.
1993c. Draft Project Description, Wilmington
Harbor Ocean Bar, May, 1993. Wilmington District, U.S.
Army Corps of Engineers, Wilmington, N.C. 4 pp.
38
•

v
U.S. Fish and Wildlife Service. 1988a. Planning Aid Report -
Wilmington Harbor Passing Lane. Raleigh Field Office,
Raleigh, NC. 36 pp.
1988b. Final Fish and Wildlife Coordination
Act Report. Wilmington Northeast Cape Fear River. Raleigh
Field Office, Raleigh, NC. 24 pp + App.
. 1989. Planning Aid Report. Wilmington Harbor
Turns and Bends. Raleigh Field Office, Raleigh, NC. 31 pp.
1990. Draft Fish and Wildlife Coordination Act
Report. Wilmington Harbor Passing Lane. Raleigh Field
Office, Raleigh, NC. 51 pp.
1991. Draft Fish and Wildlife Coordination Act
Report. Wilmington Harbor Turns and Bends. Raleigh Field
Office, Raleigh, NC. 55 pp.
Van Dolah, R.F. and D.M. Knott. 1984. A Biological
Assessment of Beach and Nearshore Areas along the South
Carolina Grand Strand. Final Report to U.S. Department of
the Interior, Fish and Wildlife Service. Marine Resources
Division, South Carolina Wildlife and Marine Resources
Department, Charleston, South Carolina, 58 pp.
Weakley, A.S. and M.A. Bucher. 1992. Status survey of
seabeach amaranth (Amaranthus pumilus Rafinesque) in North
and South Carolina, second edition (After Hurricane Hugo).
Report to North Carolina Plant Conservation Program, North
Carolina Department of Agriculture, Raleigh, N.C. and
Endangered Species Field Office, United States Fish and
Wildlife Service, Asheville, North Carolina. 178 pp.
Webster, W.D., J. F. Parnell, and W. C. Biggs. 1985. Mammals
of the Carolinas, Virginia and Maryland. The University of
North Carolina Press, Chapel Hill, North Carolina. 255 pp.
39
I
I
r
t
June 4 1993
t
Memorandum
To: Monica Swihart
Through: John Dorne
From: Eric Galamb
Subject: EA/FONSI Wilmington Harbor Ocean Bar Channel Deeping
DEHNR # 93-0965, DEM # 9556
The Wetlands and Technical Review Group has no further comments on this
project.
9556.mem
P?Aw
-DEPARTMENT OF ENVIRONMENT,HEALTH,AND NATURAL RESOURCES
DIVISION OF PLANNING AND ASSESSMENT
PROJECT REVIEW FORM
CTLE EA/FONSI WILMINGTON HARBOR OCEAN BAR CHANNEL DEEPENING IN AMITH ISLAND
AREA
20JECT DISTRIBUTION LIST
NO - 93-0965 DIVISION OF MARINE FISHERIES
DIVISION OF COASTAL MANAGEMENT
)LINTY - NEW HANOVER WILDLIFE
ENVIRONMENTAL HEALTH
kTE - 06/04/93 FOREST RESOURCES
L'SPONSE DUE DATE WILMINGTON REGIONAL OFFICE
AQ, WQ, GW, LQ
ENVIRONMENTAL MANAGEMENT (WQ)
PARKS AND RECREATION
WATER PLANNING
OTHER
Y??f ? JUN 101993
JUN 9 199" _.„
LNAGER SIGN-OFF/REGION: WATER QUALITY DATE I
SECTION
i-HOUSE REVIEWER/AGENCY: DATE:
A RESULT OF THIS REVIEW, THE FOLLOWING IS SUBMITTED:
NO OBJECTION TO PROJECT AS PROPOSED
NO COMMENT
INSUFFICIENT INFORMATION
CONSISTENCY STATEMENT NEEDED. NOT NEEDED
OTHER (SPECIFY AND ATTACH COMMENTS)
ENVIRONMENTAL DOCUMENT REQUIRED UNDER THE
PROVISIONS OF NEPA AND SEPA
RETURN TO MELBA MCGEE, DIVISION OF PLANNING AND ASSESSMENT
. t?? ? 3? -.M 3 Y Y t

a A,
1777
.

'nip -

V
IP

t ?
i
iNMENTAL)ASSESSMENT
AND
FINDING OF NO SIGNIFICANT IMPACT
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
WILMINGTON, NORTH CAROLINA
June 1993
Ilk
P
r
Item Table of Contents Pag e Number

1.00 Purpo se and Need for Action 1
1.01 Introduction 1
1.02 Existing Project 1
1.03 Need for Proposed Action 2
1.04 Proposed Action 2
1.05 Proposed Construction Method 2
1.06 Proposed Disposal of Dredged Material 3
1.07 Proposed Construction Schedule 4
2.00 Incorporation by Reference 4
3.00 Alternatives 5
4.00 Affec ted Environment 5
4.01 Geology and Sediments 5
4.02 Water Resources 6
4.03 Marine and Estuarine Resources 7
4.04 Terrestrial Resources 8
4.05 Wetlands and Flood Plains 8
4.06 Endangered and Threatened Species 8
- 4.07 Cultural Resources 9
4.08 Esthetic and Recreational Resources 9
4.09 Recreational and Commercial Fishing 10
4.10 Socio-Economic Resources 10
5.00 Environmental Impacts 10
5.01 Geology and Sediments 10
5.02 Water Resources 11
5.03 Marine and Estuarine Resources 12
5.04 Terrestrial Resources 16
5.05 Wetlands and Flood Plains 16
5.06 Endangered and Threatened Species 16
5.07 Cultural Resources 17
5.08 Esthetic and Recreational Resources 17
5.09 Recreational and Commercial Fishing 17
5.10 Socio-Economic Resources 18
6.00 Compliance with Environmental Requirements 18
6.01 Water Quality 18
6.02 Ocean Disposal of Sediments 18
6.03 Endangered and Threatened Species 18
6.04 Cultural Resources 19
6.05 Executive Order 11988 (Flood Plain Management) 19
6.06 Executive Order 11990 (Protection of Wetlands) 19
6.07 North Carolina Coastal Management Program 19
7:00 Public and Agency Involvement 19
7.01 Scoping 19
7.02 Fish and Wildlife Coordination 19
7.03 Coordination of this Document 24
Item ' Table of Contents Page Number
8.00 Point of Contact 26
9.00 Finding of No Significant Impact 27
10.00 References 28
A

r
List of Figures
Figure Number Title Page Number
1 Wilmington Ocean Bar Channel Map Follows page 29
2 Wilmington Harbor Map Follows page 29
Attachments
Attachment Number Title
A Section 103 Evaluation (MPRSA)
B Pertinent Correspondence
C Recommendations of the U.S. Fish
& Wildlife Service
Page Number
Follows page 29
Follows page 29
Follows page 29
ii
ENVIRONMENTAL ASSESSMENT
AND
FINDING OF NO SIGNIFICANT IMPACT
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
WILMINGTON, NORTH CAROLINA
June 1993
1.00 PURPOSE AND NEED FOR ACTION
1.01 Introduction. The Wilmington Harbor ocean bar channel (also called
" Baldhead Shoal Channel) extends seaward from the mouth of the Cape Fear River
(figure 1) and provides the entrance to the Port of Wilmington, which is lo-
cated about 26 miles upriver. The ocean bar channel has been maintained by
the Federal Government for well over 100 years. Its most recent improvements
were constructed pursuant to a congressional authorization to widen it from
400 feet to 500 feet and deepen it from 35 feet to 40 feet at mean low water
(mlw, which is the datum to which all depths are reported in this document).
This work was completed in 1973, but the authorized project depth of 40 feet
was not achieved due to rock obstructions and bathymetric survey inaccuracies.
The actual controlling depth for navigation is 38 feet. This depth is not
adequate to allow full utilization of the interior channels of the Wilmington
Harbor. Currently, the larger vessels calling at the port must be lightloaded
and/or wait for high tide due to the depth constraint in the bar channel. The
North Carolina State Ports Authority (NCSPA) has requested that the ocean bar
channel be deepened to the project depth authorized in the River and Harbor
and Flood Control Act of 1962.
1.02 Existing Project. The currently authorized Wilmington Harbor project is
30.8 miles long and provides for an entrance channel 40 feet deep and 500 feet
wide from the Atlantic ocean through the ocean bar and entrance channels to
Southport, thence 38 feet deep and 400 feet wide, with increased widths at
bends, to the upper end of the anchorage basin (foot of Castle Street) at
Wilmington; thence 32 feet and 400 feet wide to the Hilton Bridge over the
Northeast Cape Fear River, with increased widths at bends; for an anchorage
basin at Wilmington 38 feet deep, 2,000 feet long, 900 feet wide at the upper
end, 1,200 feet wide at the lower end, with approaches 1,500 feet long at the
upper end and 4,500' feet long at the lower end, with some widening in the
transition channel at the downstream end; for a turning basin opposite the
principal terminals at Wilmington 32 feet deep, 1,000 feet long, 800 feet
wide, with suitable approaches at each end; for a channel 12 feet deep and 100
feet wide northwestward from the Intracoastal Waterway at Snows Cut to the
main river channel; and for a channel 25 deep and 200 feet wide from the
Hilton Bridge over the Northeast Cape Fear River upstream 1.67 miles, includ-
ing a turning basin of the same depth 500 feet wide by 700 feet long located
1.25 miles above the bridge. An overdepth of two feet for dredging inconsis-
tencies is allowable throughout the project. Areas of rock require 1
additional foot of overdepth for vessel safety. A general project map appears
in figure 2. It is important to note that the project authorization provides
for a depth of 40 feet on the ocean bar versus 38 feet in the river up to
Castle Street. The 2-foot difference is the required allowance for wave ac-
tion and safety in the ocean environment for a ship loaded to utilize a still
water depth of 38 feet.
The most recent improvements to the ocean bar channel were completed in 1973.
Continuation of the operational capability of this channel depends upon main-
tenance dredging which is usually conducted once per year. Annual maintenance
dredging from 1970 through 1992 produced an average of about 843,000 cubic
yards of mixed sand, silt, and clay from Baldhead Shoal Channel and the ad-
jacent four upstream channel reaches (Smith Island Channel, Caswell-Southport
Channel, Southport Channel, and Battery Island Channel), collectively.
Maintenance of these five channels is accomplished by ocean-going hopper
dredges, and dredged material is placed in the U.S. Environmental Protection
Agency (USEPA) designated Wilmington Ocean Dredged Material Disposal Site
(ODMDS). Ocean-certified hydraulic pipeline dredges are now also available to
perform this work, although they have not yet been used for routine main-
tenance dredging on this group of channels.
1.03 Need for Proposed Action. Because of the shortfall in channel depth at
the ocean bar, the effect of the ocean wave climate, and the risk of hull
damage posed by the rock bottom, ocean-going vessels must lightload and/or
wait for high tide to cross the bar. Thus they cannot fully utilize the 38-
foot depth of the river channel to the State Port facility for maximum
benefit. Lightloading and/or delays are very. costly to shippers--and--the-over---- - -
all economy of the port. The NCSPA has requested that the Corps of Engineers
provide the authorized project depth and appropriate overdepth at the ocean
bar to allow for full use of the river channels under normal tidal conditions.
1.04 Proposed Action. It is proposed to provide the authorized channel depth
of 40 feet from the intersection of Smith Island Channel (station 0+00)
seaward along the existing ocean bar channel alignment to the -40-foot contour
(station 305+00), a distance of about 30,500 feet or 5.8 miles (figure 1). In
addition, 1 foot of overdepth is required in rock areas and 2 feet of over-
depth is allowable for dredging inconsistencies thoughout the length of the
channel. The authorized channel depth already exists from station 0+00 to
station 125+00, so the new work is required only seaward from station 125+00.
Since the existing channel ends at station 240+00, the improved channel will
represent a seaward extension of about 6,500 feet. Maintenance dredging of
the improved channel will be accomplished using the same dredging methods and
disposal area described above. It is estimated that maintenance of the im-
proved channel will result in an annual increase of about 128,000 cubic yards
of material. It is expected that maintenance dredging will continue to be
conducted at a frequency of about once each year.
0

1.05 Proposed Construction Method. Project construction will involve the
removal of an estimated 1,640,000 cubic yards of material from the ocean bar
channel. Of this amount, about 930,300 cubic yards of material will come from
new areas of the channel (all material between elevations -42 and -43 feet mlw
from stations 125+00 to 240+00, all rock protruding above elevation -42 feet
mlw between stations 125+00 and 240+00, and all material above elevation -43
feet mlw from station 240+00 to 305+00). It is estimated that rock comprises
about 830,000 cubic yards, or about 89 percent, of this material and that
about 100,300 cubic yards are comprised of mixed sand, silt, clay, and a small
2
amount of shell fragments. In addition to this material, about 709,700 cubic
yards of sediment will also be removed from the zone that has been allowable
overdepth during previous dredging cycles (material between -40 and -42 feet
mlw from station 125+00 to 240+00). Removal is expected to be primarily by
hydraulic pipeline dredge with a rock cutterhead. However, hopper dredges or
other types of cutterheads on pipeline dredges could be used for the removal
of sediments. Sediments will be delivered to the point of disposal within the
ODMDS either by pipeline or by a surface vessel (scow, barge, or hopper
dredge). Prior to its removal, some rock may require drilling and blasting
due to a combination of factors that would prevent cost-effective removal by
dredging only. Such complicating factors may include rock hardness, thick-
ness, joint spacing, spacing and strength of planes of weakness, orientation
of the rock mass, and possibly other factors as well. As a worst case, it is
estimated that such non-dredgeable rock, if present, comprises less than
14,000 cubic yards or less than 2 percent of all the rock to be removed.
After blasting, this rock could be removed by pipeline dredge or bucket and
barge.
Dredging is intended to achieve (and the contractor will be paid for) only the
authorized project depth plus overdepth to a maximum depth of 43 feet.
However, if rock is encountered which proves to be too difficult for the
dredge to remove effectively, the dredge will be allowed to undercut such rock
so as to fracture it to allow its subsequent removal or to let it remain at
the channel bottom below the required depth of 41 feet. Such undercutting
will be allowed to a maximum depth of about 48 feet since the dredge cutter-
head may have a diameter of about 5 feet, and it may need to operate below the
normal maximum depth of 43 feet. It is expected that only a small amount of
undercut dredging will be conducted because it will involve the removal of
material below the zone for which the contractor will be paid (i.e. below 43
feet). The purpose of allowing this procedure is to reduce the potential re-
quirement for rock blasting.
Rock blasting, if required, will involve drilling holes into the rock and in-
serting explosive charges into the holes. Prior to detonation, procedures
will be followed to reduce potential adverse impacts. The top 1 foot, or
more, of each hole will be filled with crushed stone or gravel, a procedure
known as stemming. Also, a firing delay of at least 25 milliseconds will be
required after each row of holes and before the next row is fired. Reasons
for the use of these measures and an explanation of their benefit in reducing
adverse blasting impacts are discussed in section 5.03 of this report. Based
upon a worst-case assumption of 14,000 cubic yards of non-dredgeable rock, it
is expected that no more than 60 blasts would be required. This assumes that
the maximum number of holes per day would be drilled and then fired together
as a unit making up one blast.
1.06 Proposed Disposal of Dredged Material. Disposal of dredged material
will be primarily in the Wilmington ODMDS, which was designated by the USEPA
(final designation August 3, 1987, by 52 FR 25008 et seq.). The material will
be localized within the most eastern quadrant of the ODMDS, which is most dis-
tant from the navigation channel, to reduce any potential navigation hazard
posed by rock. Mounding of dredged material will be controlled to assure at
least 25 feet of vertical clearance for navigation above it.
3
The North Carolina Division of Marine Fisheries (NCDMF) Artificial Reef
Program and the National Marine Fisheries Service (NMFS) were consulted con-
cerning the possible use of dredged rock for the construction of an offshore
fishing reef. However, this concept has limited applicability based on data
from small-scale test pits which were excavated by rock cutterhead dredging at
the ocean bar channel in March 1992. The rock produced by the grinding action
of the cutterhead was generally too small to provide good quality reef con-
struction material. It was estimated that only about 10 percent of the
dredged rock was 8-inch-diameter or larger. Also, the proposed dredging will
collect the rock from the channel along with the overlying sediments to
produce a mixture which would be even less suitable for reef construction. If
any rock requires blasting, it may be somewhat better quality and may be used
for fishery reef construction if it is suitable. Reef sites which may be used
include only those which are part of the NCDMF Artificial Reef Program and
which are permitted by the Department of the Army (Permit No. 198500194; ef-
fective January 1,1992,, through December 31, 1997). The NCDMF has expressed
interest in deploying rock at Reef Site AR-445, which is located about 9.8
nautical miles southwest of the channel entrance buoy (buoy 2CF). An alterna-
tive also being considered is Reef Site AR-420, which is located about 2.9
nautical miles northwest of buoy 2CF.
Analysis of sediment grain size samples indicates that the material proposed
for dredging does not contain a sufficent amount of beach quality sand to make
beach nourishment a viable _disp_osa1_ alternative.
1.07 Proposed Construction Schedule. Project design is scheduled to be com-
plete and the project available for initiation of construction no later than
July 1994, subject to the availability of funds. It is estimated that the
work will require about 16 months for completion.
2.00 INCORPORATION BY REFERENCE
Dredging and disposal methods for maintenance of the Wilmington Harbor project
have been addressed in previous environmental documents which were circulated
for public and environmental agency review. These documents indicate the en-
vironmental acceptability of these methods, which are also planned for the
proposed improvements. Aspects of the proposed new work which are different
include excavation of dredged material from areas that have not previously
been dredged, the potential requirement for limited rock blasting, and the
potential transport and deployment of rock to an artificial reef site managed
by the North Carolina Division of Marine Fisheries. Accordingly, this assess-
ment addresses the environmental effects only for these different aspects of
the new work dredging and incorporates, by reference, the environmental ef-
fects of dredging and disposal previously addressed. The following documents ,4
are incorporated by reference:
a. U.S. Army Engineer District, Wilmington. Environmental Assessment and
Finding of No Significant Impact, Excavation of Pits. Wilmington Harbor.
Baldhead Shoal Channel, Brunswick County. North Carolina, October 1991.
. b. U.S. Army Engineer District, Wilmington. Environmental Assessment and
Finding of No Significant impact, maintenance Dredging in Wilmington Harbor
Ocean Bar Channels by Ocean-Certified Pipeline, or Bucket and Barae Dredge
4
with Disposal in the Wilmington Harbor Ocean Dredged Material Disposal Site,
August 1991.

c. U.S. Army Engineer District, Wilmington. Final Environmental Impact
Statement (FEIS). Long-Term Maintenance of Wilmington Harbor, North Carolina,
October 1989.
d. U.S. Environmental Protection Agency. Final Environmental Impact
Statement (FEIS), Savannah, GA, Charleston, SC, and Wilmington, NC, Ocean
Dredged Material Disposal Sites Designation, October 1983.
3.00 ALTERNATIVES
The alternatives addressed are (1) to correct the existing depth deficiency at
the Wilmington Harbor ocean bar channel and (2) to take no action. The
selected plan is to correct the project depth deficiency by providing the
authorized project depth of 40 feet, plus one foot of overdepth in rock, plus
two feet of allowable overdepth for dredging inconsistencies throughout the
channel length (total allowable dredging depth of 43 feet in rock; 42 feet
otherwise). The overdepth requirements are based upon Corps of Engineers
regulations (ER 1130-2-307).
The proposed plan is economically feasible and has a benefit-cost ratio of
1.8 using expected base year (1995) benefits and 2.4 including the present
worth of future benefit increases. The proposed plan has an estimated first
cost of $51.5 million and an estimated average annual cost of $4.7 million.
The plan is the minimum construction required (including appropriate
overdepth) to obtain the authorized project.
The "no action" alternative would continue to have vessels light-loaded be-
cause of restrictions on the ocean bar. Shippers would not be able to fully
use the 38-foot interior channels to Wilmington, increasing the cost of
freight - which is ultimately passed on to consumers. Shippers would require
more vessel trips to carry the same amount of goods. Expected increases in
waterborne commerce would exacerbate this problem in the future.
4.00 AFFECTED ENVIRONMENT
14
4.01 Geoloav and Sediments. Sediments in the channel area generally consist
of sands, silts, and clays occurring in various mixtures. Occasionally, these
sediments may contain gravel, shell fragments, and limestone fragments. The
sediments overlie carbonate rocks having different degrees of cementation and
hardness. Data from seismic surveys and core borings show that the top of
rock (TOR) occurs approximately at elevation -70 feet.mlw from station 0+00 to
station 95+00 and rises to approximately -50 feet mlw at station 125+00.
Seaward to station 305+00 (new end of project) the TOR varies from about -38
feet mlw to -43 feet mlw. Rock formations encountered in borings of this
area, from youngest to oldest, are tentatively identified as the Waccamaw for-
mation, Castle Hayne Limestone (Unit B), Castle Hayne Limestone (Unit A),
Turritellid Limestone, and Olive Sand. The Castle Hayne Limestone is one of
the regional groundwater sources for southeastern North Carolina. This forma-
tion is discontinuous in the vicinity of the ocean bar.
5
Sediments from the channel (fine-grained maintenance materials) were chemi-
cally and biologically tested in 1992. The tests indicate that these
sediments meet the criteria of the USEPA Ocean Dumping Regulations and
Criteria (40 CFR 220-229) and are, therefore, acceptable for ocean dumping un-
der Section 103 of the Marine Protection, Research, and Sanctuaries Act
(MPRSA) of 1972 (PL 92-532), as amended. USEPA, Region IV, concurred, by let-
ter dated December 31, 1992, that this material was suitable for disposal for
one dredging cycle, with general concurrence pending completion of the sedi-
ment testing data package for the entire Wilmington Harbor project. The new
work materials are believed to be similar to the maintenance materials tested
or even less affected by anthropogenic contaminants due to their deeper and
more isolated locations. The sediment test data and interpretation of results
are presented in the Section 103 Evaluation Report included as Attachment A.
Rock from coastal areas with strong currents is environmentally acceptable for
ocean dumping without testing (40 CFR 227.13 (b)(1)). USEPA concurrence for
ocean disposal of the new work sediments is now being requested.
4.02 Water Resources.
A
w
Hydrology. Ocean water depths range from about 1 foot on the shoals adjacent
to the channel near station 00+00 to about 18 feet near station 125+00
(beginning of new work) to about 40 feet near the seaward end of the channel.
Tides in the area are semidiurnal and the mean tidal range, measured at
Baldhead, is 4.9 feet._ Theaverage _ discharge---of--the-Cape Fear River at-its
-
mouth is about 11,000 cubic feet per second. The salinity of the area varies
due to many factors including freshwater inflow, tidal action, and wind, so
that the salinity may range from about 23 parts per thousand (ppt) to almost
normal ocean salinity (35 ppt) (CP&L, 1980).
Water Ouality Classification. Waters of the Atlantic Ocean in the vicinity of
the Cape Fear River mouth are classified "SB." "SB" waters are suitable for
primary and secondary recreation, fishing, fish and wildlife propagation, and
other uses requiring water of lower quality (15 NCAC 2B .0311).
Groundwater.. In the Wilmington Harbor vicinity, groundwater is supplied
primarily by two aquifers. In descending order of elevation, they are the
water table aquifer of the undifferentiated surficial sands and the Castle
Hayne Limestone. A discontinuous aquitard of Pleistocene age silts and clays
may overlie the Castle Hayne aquifer, but there is an undetermined amount of
connection between the surficial sands and the Castle Hayne aquifer. Most
domestic water wells are set in the surficial sands. The second most used
aquifer for water supply is the Castle Hayne Limestone.
Locally, vertical groundwater movement may occur downward through the surfi- y,
cial sand, through the discontinuous aquitard, to the Castle Hayne Limestone.
Regionally, the horizontal groundwater movement is eastward with some
southeast movement. The resultant groundwater movement is toward the coast.
6
4.03 Marine and Estuarine Resources.
Nekton. Nekton of the nearshore Atlantic Ocean along southeastern North
Carolina can be placed in three categories: estuarine dependent species;
seasonal migrant species; and permanent resident species. The most abundant
nekton of these nearshore marine waters are the estuarine dependent species,
which spawn offshore, move into the estuary as larvae, and migrate back into
the ocean as juveniles or adults. This group includes species such as the
Atlantic croaker (Micropooon undulatus), spot (Leiostomus xanthurus), weakfish
(Cvnoscion regalis), star drum (Stellifer lanceolatus), red drum (Sciaenops
ocellatus), banded drum (Larimus fasciatus), Atlantic menhaden (Brevoortia
tyrannus), southern kingfish (Menticirrhus americanus), flounders
(Paralichthvs spp.), mullets (Mu it spp.), anchovies (Anchoa spp.), blue crab
(Callinectes sapidus), and penaeid shrimp (Penaeus spp.). Species which are
permanent residents of the nearshore marine waters include the black sea bass
(Centropristis striata), longspine porgy (Stenotomus caprinus), Atlantic
bumper (Chloroscombrus chrvsurus), inshore lizardfish (Synodus foetens), and
searobins (Prionotus app.). Common warm water migrant species include the
bluefish (Pomatomus saltatrix), Spanish mackerel (Scomberomorus maculatus),
king mackerel (Scomberomorus cavalla), cobia (Rachycentron canadum), Florida
pompano (Trachinotus carolinus), and spiny dogfish (Saualus acanthias).
Anadromous species such as blueback herring (Alosa aestivalis), American shad
(Alosa sayidissima), hickory shad (Alosa mediocris), alewife (Alosa
pseudoharenaus), striped bass (Morone saxatilis), and Atlantic sturgeon
(Acivenser oxvrhvnchus) pass through the nearshore ocean and Cape Fear estuary
en route to upper river spawning and nursery areas (Walburg and Nichols, 1967;
Nichols and Louder, 1970). Anadromous fish use is highest from mid-winter to
mid-spring. The shortnose sturgeon (Acipenser brevirostrum), which is
Federally listed as endangered, is an anadromous species known to occur in the
Cape Fear River. Its occurrence in the nearshore ocean has not been con-
firmed, and it is possible that the Cape Fear River population does not make
ocean runs, as is true of some northern populations of sturgeon. The
catadromous American eel (Anguilla rostrata), is widely distributed in the
Cape Fear River estuary and migrates through the area of the bar channel
(Schwartz et al., 1981).
Marine mammals also occur in North Carolina's coastal waters. The Federally-
endangered right whale (Eubaleana alacialis) and humpback whale (Meaaptera
novaeanaliae) are spring and fall migrants off the coast, and the right whale
appears to prefer shallow water. A number of other whale and dolphin species
normally inhabit deeper waters offshore, while the bottlenose dolphin
(Tursiops truncatus) and the harbor porpoise (Phocoena phocoena) utilize near-
shore waters. The bottlenose dolphin is common in the project area.
The State of North Carolina defines primary nursery areas as those areas in
the estuarine system where initial post-larval development takes place. The
ocean bar channel is not located within a designated primary nursery area (15
NCAC 3B .1405).
Benthos. Benthic communities of the project area exhibit a wide range of or-
ganism composition and density, and community structure is highly dependent on
substrate type and salinity regime. Benthic organisms in this area of the
7
nearshore ocean were observed by Birkhead et al. (1979) at densities ranging
from about 90 per square meter on sand bottom to over 500 per square meter on
mud substrate. This study reported the tube dwelling spionid polychaete,
Spionhanes bombvx, as the dominant component of the benthos collected from a
spot off the eastern end of Oak Island and other locations where substrates
were predominantly mud or mud-sand mixtures. Other dominants reported from
this marine area included the magelonid polychaete, Magelona sp.; the capitel-
lid polychaete, Heteromastus filaformis; the spionid polychaete,
Paraprionospio pinnata; the sea pansy, Renilla reniformis; and an unidentified
brittlestar (amphiurid). Additional taxa reported in high numbers included
the echinoid, Mellita auinauiesperforata; the onuphid polychaete, Diopatra
cuprea; and the nephtyid polychaete, Nephtvs iv cta.
4.04 Terrestrial Resources. All the proposed work will occur at sea, so
there are no terrestrial areas affected by the proposed plan. The closest
nearby lands are the beaches of Bald Head island, which are more than 1.8
miles away from the proposed work. Beach nourishment is not considered a vi-
able disposal alternative, because there is insufficient beach-quality sand in
the sediment to be dredged.
4.05 Wetlands and Flood Plains. The proposed work is not located in any wet-
lands or flood plains, nor will it directly affect any wetlands or flood
plains.
4.06 Endangered and Threatened Species. Lists of threatened or endangered
species for the project area were requested from NMFS (Southeast Regional
Office, St. Petersburg, FL) and the U.S. Fish and Wildlife Service (USFWS)
(Field Office, Raleigh, NC). The lists provided by these agencies were com-
bined to develop the following composite list which was used during project
planning.
MAMMALS
Eastern cougar (Felix concolor cougar) - Endangered
Finback whale (Balaenoptera phvsalus) - Endangered
Florida manatee (Trichechus.manatus) - Endangered
Humpback whale (Meaantera novaeanaliae) - Endangered
Right whale (Eubaleana glacialis) - Endangered
Sei whale (Balaenoptera borealis) - Endangered
Sperm whale (Phvseter catodon) - Endangered
BIRDS
Arctic peregrine falcon (Falco peregrinus tundrius) - Threatened M
Bald eagle (Haliaeetus leucocephalus) - Endangered
Piping plover (Charadrius melodus) - Threatened
Red-cockaded woodpecker (Picoides borealis) - Endangered
Wood stork (Mvcteria americana) - Endangered
8
REPTILES

American alligator (Alligator mississippiensis)
Green sea turtle (Chelonia mvdas) - Threatened
Hawksbill sea turtle (Eretmochelvs imbricate)
Kemp's ridley sea turtle (Lepidochelvs kempi) -
Leatherback sea turtle (Dermochelvs coriacea) -
Loggerhead sea turtle (Caretta caretta) - Threa
FISHES
Threatened/SA*
- Endangered
Endangered
Endangered
tened
Shortnose sturgeon (Acivenser brevirostrum) - Endangered
PLANTS
Cooley's meadowrue (Thalictrum coolevi) - Endangered
Rough-leafed loosestrife (Lvsimachia asperulaefolia) - Endangered
Sea-beach amaranth (Amaranthus pumilis) - Threatened
*The American alligator is listed as threatened only because of its
similarity of appearance to crocodilians which are endangered or threatened
and which are tracked for illegal commercial trade in hides or other
products. The status of the American alligator is not actually threatened.
4.07 Cultural Resources. The lower Cape Fear River and adjacent offshore
waters are recognized as one of the richest repositories of historic
shipwrecks in North Carolina, and one of the richest in the nation. The
potential for significant cultural resources to exist in the vicinity of the
proposed project has been documented in numerous past studies that have con-
tributed to the creation of the National Register of Historic Places Cape Fear
Civil War Shipwreck District (CFCWSD). The CFCWSD, comprised of discontinuous
offshore areas from Carolina Beach Inlet to Lockwoods Folly Inlet, includes a
National Register site, the blockade runner Ella, which is located near the
western tip of Baldhead Island. The North Carolina Division of Archives and
History (NCDAH) site files list 33 wrecks which are known to have occurred .in
the vicinity of Old Inlet - many on the ocean bar. Some of the 50 documented
wrecks between Southport and Wilmington may be in the project vicinity since
many of the locations are reported to be in the vicinity of Smithville
(Southport) or the mouth of the river. The seaward extension of the proposed
channel as well as the new side-slopes and a 150-foot band outside each top
slope intercept were investigated in 1992 and 1993 during a remote sensing
survey by magnetometer and side-scan sonar. This study identified seven
anomalies, but only one of potential significance. A subsequent diver inspec-
tion identified the object as a modern navigational aid which has no
historical significance. Due to concerns over the potential impacts of blast-
ing, additional survey is being conducted for a buffer zone of 300-foot width
outside portions of the previously surveyed area. The results of these
studies will be coordinated with the NCDAH during June and July 1993.
4.08 Esthetic and Recreational Resources. All the proposed work will occur
at sea and over 1.8 miles from the nearest land at Bald Head Island. The
marine environment of this area provides opportunities for boating and fish-
ing, as well as escape from the faster pace of land-based activities. A
9
nautical atmosphere is provided by the numerous vessels common to these
waters, including commercial and recreational boats as well as ships calling
on the port.
4.09 Recreational and Commercial Fishina. Recreational, part-time commer-
cial, and full-time commercial fishermen utilize these nearshore marine
waters. Species sought by anglers include flounder, trout, spot, croaker,
bluefish, Spanish mackerel, king mackerel, penaeid shrimp, and blue crabs.
The area between Bald Head Island and the ODMDS east of the ocean bar channel
is commonly fished by trawling.
4.10 Socio-Economic Resources. The Wilmington Harbor project contributes
significantly to the economic benefit of the Nation. The harbor handled an
average of 6.8 million tons of commerce each year for the last 10 years. The
value of foreign imports and exports in 1991 for the Wilmington customs dis-
trict was $6.2 billion. Commerce through the port generated at least 46,000
jobs in North Carolina and about $1.2 billion of income to the State in 1992.
Benefits from the harbor are expected to increase with future commerce growth.
5.00 ENVIRONMENTAL IMPACTS
The proposed dredging and dredged material disposal methods and their environ-
mental effects will be similar to those discussed in previous environmental
documents concerning maintenance--dredging-(incorporated by referencein sec-
tion 2.00). The proposed improvement of the ocean bar channel will differ in
that dredging will occur in areas that have not previously been dredged,
limited rock blasting may be required, and rock may be transported to and
deployed at an artificial reef site managed by the NCDMF. Only the impacts
related to new work are addressed here.
5.01 Geoloav and Sediments. Removal of sediments and rock associated with
the proposed work is not expected to produce any significant adverse impacts.
Sediments of the general vicinity, including the channel bottom, the ODMDS,
and the nearshore ocean, are continually subject to movement facilitated by
strong currents. Redistribution of sediment is, therefore, a natural occur-
rence. Disposal of sediments in the ODMDS has been addressed in the
referenced environmental documents (section 2.00) and is environmentally ac-
ceptable. The results of 1992 chemical and biological tests indicate that the
sediments from the ocean bar channel are acceptable for ocean disposal. These
results appear in the Section 103 Evaluation Report at Attachment A and are
being coordinated with USEPA, Region IV to obtain concurrence for ocean dis-
posal. Rock from coastal areas with strong currents is environmentally
acceptable for ocean dumping without testing. Disposal in the ODMDS of any
rock or sediment from the proposed channel is, therefore, not expected to
produce any significant adverse effects.
Dredging and/or blasting may increase the permeability of the rock formation
at the channel bottom. However, the Castle Hayne Limestone appears to be dis-
continuous here, it is not overlain or protected by other rock formations, and
it is already exposed to seawater. Therefore, significant changes or impacts
are not expected.
M1
10
The proposed action will have no effect o
will begin at a point approximately 2 miles
This point is beyond the zone of littoral
should be unaffected.
n the littoral processes. The work
seaward from the river mouth.
sand transport, so adjacent beaches
5.02 Water Resources.

Groundwater. Neither dredging nor rock blasting will adversely affect
groundwater of the area. The Castle Hayne Limestone formation at the channel
bottom is already exposed to salt water. Groundwater in the area moves
generally east and southeast along a regional gradient of about 8 feet per
mile. The potential for saltwater intrusion into groundwater does not exist
unless a reversal of hydrologic gradient occurs due to excessive groundwater
pumping. If blasting is conducted, the upper areas of rock will be fragmented
and some permeability increase may occur, but the effect will be negligible.
Water supplies of nearby communities will not be affected by the proposed ac-
tion.
Water Ouality. The water quality impacts of dredging and disposal have been
addressed in the documents incorporated by reference in section 2.00. These
impacts include minor and short-term suspended sediment plumes and the release
of soluble trace constituents from the sediment. Suspended sediments also af-
fect turbidity, an optical property of water (measured in nephelometric
turbidity units, or NTUs). Turbidity increases outside the dredging area
should be less than 25 NTUs and are, therefore, considered insignificant.
Overall water quality impacts will be short-term and minor. Living marine
resources dependent upon good water quality will experience no significant ad-
verse impacts due to water quality changes.
Hydrology. Marine waters of the project area display considerable daily
variation in current and salinity conditions due to fresh water inflow, tides,
and wind. Any project-induced changes in the vicinity of the proposed im-
provements would be very small (if any) in comparison and are, therefore,
considered to be insignificant.
Potential salinity-intrusion into the Cape Fear River was evaluated by the use
of a one-dimensional, quasi-steady state model (Ippen 1966). This model in-
corporates several variables, including freshwater velocity, estuarine channel
width, estuarine channel depth, tidal amplitude, inflow velocity into the
river, and ocean salinity. Of these six variables, it is obvious that the
proposed work can have no effect on the first four listed. With regard to the
fifth variable, inflow velocity, analyses indicate that project-related
changes will occur beyond the seaward influence of the river ebb flow cur-
rents, which are stronger than flood flow currents. Therefore, the channel
modification will not have an effect on the inflow velocity. Considering the
sixth variable, ocean salinity, any project-related changes will occur in the
open ocean and approximately two miles or more from the river. There is no
mechanism for such changes to have an effect on the ocean's salinity or the
salinity distribution in the Cape Fear River. Therefore, no changes are an-
ticipated in the hydrology or salinity of the Cape Fear River.
11
5.03 Marine and Estuarine Resources. Project-related activities may have
direct but insignificant physical impacts on living marine and estuarine
resources. Sources of such impacts include (1) dredging and, disposal, (2) un-
derwater rock blasting, and (3) the transportation and deployment of rock for
a fishery reef.
Nekton. Free-swimming animals are not expected to experience any significant
effects from the dredging or disposal operations. Most will be able to avoid
or escape contact with dredges and their operating equipment. Since the work
will occur more than 1.8 miles at sea, there should be very little interrup-
tion of the movement of fish, including anadromous fish, to and from spawning
areas in the Cape Fear River estuary due to the physical presence of dredging
equipment or the physical-chemical water quality changes associated with
dredging. Larvae of numerous species of nekton are subject to passage through
the suction equipment of a dredge, if they are present at the dredge cutter-
head. However, the volume of water passed through the dredge is negligibly
small in comparison to the volume of water in this region of the open ocean.
Larvae are not expected to be unduly concentrated in the immediate dredging
area, so no significant larval impacts are expected.
Transportation of rock in surface vessels to a reef site is also not expected
to jeopardize any marine animals to any greater extent than other vessel traf-
fic. The dumping of rock at a reef site or at the ODMDS could kill or injure
any animals directly _under -the-barge-or --scow-at-the -time-of--dumping, -but most
are expected to escape and any effects of this type should be minor.
If blasting is conducted, some losses of nekton are expected to occur in the
immediate vicinity of the blasts. Explosions in the marine environment can
injure and/or kill fish, marine mammals, sea turtles, and other marine life.
Underwater shock waves from high-velocity explosives have been reported to
result in the rupture of the swimbladder and other internal organs of fish,
and damage to the lungs, intestines, and the auditory systems of marine mam-
mals. Damage to sea turtles is thought to resemble that observed in mammals,
i.e., to lungs, intestines, and auditory systems (O'Keeffe and Young, 1984).
Studies have shown that the degree of impact experienced by fish as a result
of explosions is determined by several factors, including physical charac-
teristics of the fish, the weight of the explosive charge, and the distance of
the fish from the charge. Swimbladder fish have been found to be more suscep-
tible to damage from shock waves than non-swimbladder fish (most common marine
fish except flounders have swimbladders), and smaller fish are more suscep-
tible to damage than larger fish of the same species (Wright, 1982). Larval
fish are less sensitive to the effects of shock waves than eggs or than post-
larval fish in which the swimbladder has developed (Rasmussen, 1967; as cited
in Wright, 1982). The damaging effects on marine life increase in relation
(but not in direct proportion) to increasing the weight of the explosive
charge. The shock wave from an underwater explosion diminishes over distance
at a rate proportional to the cube root of the weight of the explosive charge.
Therefore, the peak pressure generated by an 8-pound charge at a specific dis-
tance is only about twice the peak pressure of a 1-pound charge at the same
distance (2 is the cube root of 8). Thus, doubling the weight of an explosive
charge does not double the impact to marine life (Young, 1991). Also, the
•
12
further an animal is located from an explosive charge, the greater will be its
chances of survival.
IK
Mitigative measures will be employed during underwater blasting in order to
reduce potential impacts to marine life. These measures include the stemming
of the holes in which the explosive charges are placed, the use of instan-
taneous delays between portions of the charge, and reducing the overall number
of blasting events. Stemming is a procedure in which the top 1 foot, or more,
of each hole containing an explosive charge is filled with crushed stone or
gravel. This process partially contains the explosive force, increases the
amount of work done to surrounding rock, and reduces the impact to the aquatic
environment above. The use of instantaneous delays effectively reduces each
detonation into a series of small explosions, and the resulting blast over-
pressure levels are directly related to the size of the charge in each delay
rather than the summation of charges detonated in all holes (Munday et al.,
1986). Thus, a large weight of explosive charge can be fired as a series of
smaller charges with a major reduction in impacts. Reduction of the number of
blasting events required to perform a job can be achieved by'drilling the max-
imum number of holes per day and then firing them as a unit making up one
blast (but including the delays mentioned above to prevent cumulative impact
from the increased weight of explosive charge).
Because of the harmful impacts of blasting on marine life, much research has
focused on the development of models to predict the lethal distances of under-
water explosions. Knowledge concerning potential lethal distances is useful
in assessing potential adverse impacts on marine life and in establishing
preventive measures. Models have been developed that are based upon various
methodologies, but the impulse strength model appears to be the best at
predicting lethal and safe ranges under various sets of conditions and assump-
tions (Wright, 1982). The St. Louis District (SLD), Corps of Engineers has
developed a computer mathematical model, based upon the impulse strength
method, to predict the kill radius for swimbladder fish from explosions that
are buried in holes drilled in a rock substrate. This model takes into ac-
count (1) the effects of different explosive charge weights, (2) the greater
susceptibility of smaller fish to blast damage, (3) the constraining effects
of stemming on the overall explosive impact, and (4) the impact reduction
achieved by employing instantaneous delays. This model was used to predict
the potential impact zone associated with blasting on the ocean bar.
The general blast plan developed by the Wilmington District for the ocean bar
channel reflects industry standards for underwater blasting and is considered
representative with respect to the technical aspects of the job. However,
normal industry procedure requires that the contractor perform limited on-site
blasting tests and adjust the final plan to actual site conditions, solo some
plan modifications may occur. The general blast plan includes the drilling of
holes on 8-foot spacing within rows and between rows; 10 holes per row and 14
rows per group; explosives totalling 365 pounds per row and 5,110 pounds per
frame; the stemming of all holes; and the addition of 25 millisecond (minimum)
delays after each row. The SLD model indicates that the use of instantaneous
delays reduces the size of the blast impact zone by approximately 75 to 80
percent. Results from the SLD model, using 2-ounce swimbladder fish as a.
worst-case example, show that the blast created by the general blast plan
13
would kill about 50 percent of the fish at a distance of 910 feet (lethal dis-
tance 50 percent, or LD50) and about 1 percent of the fish at a distance of
1,540 feet (lethal distance 1 percent, or LD1). The circular areas enclosed
by these two distances are 60 and 171 acres, respectively. Larger fish are
more resistant to blasting impacts, and 1-pound fish would experience an LD50
of about 527 feet and an LD1 of about 877 feet. Fish of 12-pound size would
experience an LD50 of about 284 feet and an LD1 of about 458 feet. These dis-
tances and their associated acreages appear below.
Blasting Impacts Estimated For A General Underwater Blasting Plan
(Stemming the top 1 foot of holes and inserting delays between rows)
---------------------------------------------------------------------
Fish LD50 Acres for LD50 LD1 Acres for LD1
Weight Feet Feet
In Lbs
------ ---- -------------- ---- -------------
0.125 910 60 1,540 171
1.000 527 20 877 56
12.000 284 6 458 15
---------------------------------------------------------------------
- The LD1 may be interpreted to represent the approximate safe range, and the
acreage associated with the LD1 approximates the potential maximum zone of im-
pact for fish of a given size. When applied to the most sensitive fish in
terms of size and type (smaller fish with swimbladders), an LD1 of 171 acres
in the above example is considered a worst case because within it there would
be many surviving fish of even the modelled size, while larger fish, non-
swimbladder fish, and marine invertebrates would survive the same blast at a
much higher percentage.
In order to develop a comparative perspective for the potential significance
of an impact zone of 171 acres, data were developed to estimate the typical
area covered by an ocean-going shrimp trawler working the North Carolina
coast. Using an average headrope length of 35 feet per trawl, an effective
net spread equal to 75 percent of headrope length, four trawls per vessel, and
a tow speed of two knots, the average area covered by trawling was computed at
about 29 acres per hour. At this rate, a shrimp trawler would cover 171 acres
in about 6 hours. Coastal North Carolina is worked by a fleet of between 100
and 200 vessels of this size and type each year (Bahen 1993).
As a related note, marine invertebrates, including clams, oysters, and crabs,
have been found to be highly resistant to explosive shock (Gaspin, 1975;
Gaspin et al., 1976; as cited in O'Keefe and Young, 1984). Young (1991)
provides methods for computing distance estimates where only 10 percent of
various types of marine invertebrates would be killed (lethal distance 10 per-
cent, or LD10) by blasting impacts. Using an example of 365 pounds of
explosive charge (the weight per delay from the example cited above for fish),
the computed LD10 is 38 feet for shrimp and 452 feet for crabs.

14
Rock blasting, if required for the proposed work, will be conducted so as to
reduce blasting impacts to the maximum practical extent, and will employ the
mitigative measures noted above (stemming, instantaneous delays, and no more
than 60 blasts). Using these procedures will not eliminate potential injuries
and deaths of ,marine fish and invertebrates, but will reduce such losses to
levels that do not have significant population impacts. It is also important
to note that blasts will normally be conducted only once or twice per day, and
that the time required for each blast is only about one tenth of one percent
of the time in a 24-hour day. Thus, while animals in the immediate vicinity
of the blast may be lost, those passing through the area will be unharmed over
99 percent of the time. This has important implications for those animals
which may be migrating through the area during the period in which blasting
activities are ongoing.
Due to special concerns for the safety of endangered and threatened animals,
this group is addressed separately in section 5.06 on the next page. However,
the observer program noted as a potential protective measure for these animals
is also applicable for marine mammals in general. Such measures would include
observers to detect the presence of mammals in the project area prior to
blasting events. Should they be observed, blasting would be delayed, if pos-
sible. After blasting, observers would also examine the area to determine if
any previously undetected mammals were killed or stunned as a result of a
blast. Through implementation of such protective measures, it is believed
that potential impacts can be minimized.
Based upon the use of the mitigative measures noted above, the limited blast-
ing of rock on the ocean bar is not expected to result in significant adverse
impacts to marine nekton populations.
Benthos. The bottom area of the existing channel (including side slopes)
covers -about 306 acres. This area is now subject to annual maintenance dredg-
ing which results in loss of benthic resources at each dredging cycle. Under
the proposed plan, the bottom subject to disturbance will cover about 393
acres, which is an increase of about 87 acres, or 28 percent. Removal of the
substrate will eliminate all benthic resources in the dredged areas. However,
an irreversible loss of resources will not occur since those areas will be
available for recolonization and use by benthic organisms after dredging. The
populations that reestablish should be similar to those eliminated, since the
species are substrate dependent and the sediments that create shoals in the
channel and adjacent areas now will continue to do so after the proposed
dredging. Annual maintenance dredging may limit the density and diversity of
the benthic community that becomes reestablished. However, benthic popula-
tions in the vicinity are in a state of flux due to the continual
sedimentation which creates the need for annual maintenance dredging.
If rock blasting is required, the worst-case assumption of 14,000 cubic yards
of rock to be blasted would correspond with less than 6 acres of blasted area
when measured at the plane at elevation -41 feet mlw (the bottom of the re-
quired overdepth zone). Experimental studies have shown that many types of
bottom-dwelling invertebrates such as sea anemones, polychaete worms, isopods,
and amphipods exhibit no damage from blasting (Gaspin, 1975; Gaspin et al.,
1976; as cited in O'Keefe and Young, 1984). Due to the small potential area
15
which may require blasting and the very high resistance of benthic animals to
blast impacts, any damage sustained by these populations should be negligible
outside the immediate blast vicinity.
The channel area proposed for dredging does not include any shallow-water
habitat, and adjacent areas of Jay Bird Shoals on the west and Bald Head Shoal
on the east are seaward of the 18-foot contour. The shallower areas of these
shoals closer to shore occur in a hydrologic regime characterized by the
presence of coarser sediments and are subject to continual sediment movement.
Therefore, they do not offer the high habitat values associated with shallow
waters within the Cape Fear River. Dredging or blasting is not expected to "
adversely affect the habitat values of any shallow-water zones.
Deployment of rock at a reef site managed by the NCDMF, if conducted, will
follow Department of the Army permit (No. 198500194, effective January 1,
1992, through December 31, 1997) criteria so as to avoid any significant ad-
verse impacts. Natural rock outcrops and their related biota (also called
live bottoms) are avoided during the selection of reef sites by the NCDMF.
Rock addition to a reef site would be a beneficial use and would support and
enhance the fishery habitat values of the reef. Appropriate interagency coor-
dination will be accomplished prior to the transportation and deployment of
rock to a reef site.
5.04 Terrestrial---Resources. -There -are -no terrestrial areas in the immediate
vicinity of the proposed work. The closest nearby lands are the beaches of
Bald Head Island, which are more than 1.8 miles away from the proposed work
and will be unaffected by the proposed work.
5.05 Wetlands and Flood Plains. The proposed work is not located in any wet-
lands or flood plains, nor will it have any significant direct or indirect
effect on any wetlands or flood plains.
5.06 Endangered and Threatened Species. Since all aspects of the proposed
work will occur at sea and no beach disposal of dredged material is planned,
the project will not affect any of the endangered or threatened terrestrial
animals, birds, freshwater animals, or plants. Thus, the eastern cougar,
Arctic peregrine falcon, bald eagle, piping plover, red-cockaded woodpecker,
roseate tern, wood stork, American alligator, Cooley's meadowrue, rough-leafed
loosestrife, and sea-beach amaranth will be unaffected by the proposed action.
Species which could be present in waters of the area during project construc-
tion include the finback whale, Florida manatee, humpback whale, right whale,
sei whale, sperm whale, green sea turtle, hawksbill sea turtle, Kemp's ridley
sea turtle, leatherback sea turtle, loggerhead sea turtle, and shortnose stur-
geon. Evaluation of the potential effects of the proposed action on these
species and their habitats will be included in biological assessments which
are being prepared and which will be coordinated with the appropriate juris-
dictional agency, pursuant to Section 7 of the Endangered Species Act of 1973,
as amended. This coordination will be completed prior to the initiation of
the proposed construction.
16
In order to assure that endangered and/or threatened species will not be ad-
versely affected by rock blasting, if it is required for project completion,
any protective agreements reached through this coordination will be incor-
porated into the contract for the proposed work. Anticipated protective
measures would include, at a minimum, observers to detect the presence of
listed species in the project area prior to blasting events. Should listed
species be observed, blasting would be delayed, if possible. After blasting,
observers would also examine the area to determine if incidental take of
listed species resulted from a blast. Through implementation of such protec-
tive measures, it is believed that potential impacts to listed species can be
` minimized.
5.07 Cultural Resources. Since all dredged material disposal will occur in
10 the previously used ODMDS and/or a previously approved artificial reef site,
only the deepening and seaward extension of the channel could produce a sig-
nificant impact. New work dredging has a potential for major impact to
historic shipwrecks if they exist in the project area. However, surveys com-
pleted in 1993, which have been accepted by the NCDAH, indicate that no
significant historic objects occur in the channel, along its side slopes, or
in its seaward extension. An in-progress supplemental remote sensing survey
is expected to determine whether significant properties occur within a blast
buffer zone consisting of an additional 300 feet along both sides of the chan-
nel. The results of this survey will be coordinated during June and July 1993
with the North Carolina State Historic Preservation Officer (NCSHPO), pursuant
to Section 106 of the National Historic Preservation Act of 1966, as amended,
to obtain concurrence for the proposed work prior to its implementation.
5.08 Esthetic and Recreational Resources. Activities associated with the
proposed plan will not significantly affect esthetics or recreation. The
presence of dredges, barges, or other water craft associated with the work
will not be unusual since maintenance dredging is conducted in the ocean bar
channel annually. These vessels will be on-site for a longer continuous
period of time than is normally required, but this is judged to be an insig-
nificant effect. Blasting, if conducted, will involve the detonation of
explosive charges buried in the substrate and under about 38 feet of water or
more. Some muffled sounds of these explosions may be detectable, but should
be inoffensive due to their low volume, infrequent occurrence, and limited
number of no more than 60 blasts.
5.09 Recreational and Commercial Fishing. Dredging and disposal should have
no significant effect on fish or fishing activities. Work vessels and/or un-
derwater disposal pipelines will avoid the fishing grounds to the maximum
extent possible. The work vessels should not unduly affect other boats since
the work will occur only in the channel (where vessels normally encounter
other navigation traffic), in the ODMDS,.or in the zone directly between the
two. Surface vessels transporting dredged material will be required to
navigate the ocean bar channel to the vicinity of the ODMDS before turning to
enter it. The allowable entry path is between the imaginary lines extended
northwesterly from the existing boundaries of the ODMDS, as shown on figure 1.
If an underwater pipeline is used, it must be located within 25 feet of the
channel top slope intercept line except in the area between the channel and
the ODMDS, where it is allowed within the same zone shown for surface vessels
in figure 1.
17
If blasting is conducted, some fish and other marine life will be killed, as
is discussed in section 5.03. However, the effect on fish populations is ex-
pected to be insignificant. Any effects on fishing should be local and short-
term.
If rock removed from the channel is added to an offshore reef site, it will
produce a beneficial effect on fishery resources.
5.10 Socio-Economic Resources. Benefits from the Wilmington Harbor to the na-
tional and regional economy are substantial and rech well beyond the
immediate vicinity of Wilmington. Personal income resulting from the commerce
through Wilmington Harbor totaled about $1.2 billion in 1992. This trade
provided jobs for at least 46,000 workers. Each 1,000 tons of cargo moved _
across Wilmnington's docks in 1992 generated about $173,000 in income and an
estimated seven jobs. Income and employment will be favorably affected by the
correction of the depth deficiency on the ocean bar.
6.00 COMPLIANCE WITH ENVIRONMENTAL REQUIREMENTS
6.01 Water ouality. The proposed discharge of dredged material will take
place outside the 3-mile limit of the territorial sea and, therefore, is regu-
lated under MPRSA of 1972 (PL -92-532), as amended. Neither a Section
404(b)(1) evaluation nor a Section 401 Water Quality Certificate under the clean -Water- Act- of-1977- (PL 95-217) ,- as -amended, is required.
6.02 Ocean Disposal of Sediments. An assessment based on USEPA's Ocean
Dumping Regulations and Criteria (40 CFR Parts 220 - 229) resulted in a deter-
mination that the sediments to be dredged during the proposed navigation
improvements are environmentally acceptable for ocean disposal. Furthermore,
the rock is excluded from testing under the MPRSA, and is also acceptable for
ocean disposal. The proposed disposal of dredged material will not cause un-
acceptable human health effects or other permanent adverse effects. The
proposed action is being coordinated with USEPA, Region IV.
Rock placed for fishery development, on a reef site that is part of a State
program certified by the USEPA, is excluded from the permit requirements of
the USEPA's Ocean Dumping Regulations (40 CFR Part 220.1 (c)(2)), provided
that certain interagency coordination requirements are met. This criterion
will be met through appropriate coordination with the National Oceanic and
Atmospheric Administration, the U.S. Coast Guard, and the Corps of Engineers
prior to any reef construction in conjunction with the proposed action.
6.03 Endangered and Threatened Species. A biological assessment evaluating
the potential impacts of the proposed action on endangered and threatened
species is being prepared and will be coordinated with the USFWS (jurisdiction
over the Florida manatee) and NMFS (jurisdiction over other listed marine and
aquatic species which may occur in the project vicinity) pursuant to Section 7
of the Endangered Species Act of 1973 (PL 93-205), as,amended. Compliance
obligations under Section 7 will be satisfied prior to implementation of the
proposed action.
18
6.04 Cultural Resources. No impacts to known archaeological or historic
resources are anticipated due to the proposed work. Project-specific historic
survey data are being coordinated with the NCDAH to obtain concurrence that
the proposed action will not cause significant adverse impacts to submerged
cultural resources.
6.05 Executive Order 11988 (Flood Plain Management). No flood plains will be
impacted by the proposed action. The proposed action is in compliance with
the requirements of Executive Order 11988, Flood Plain Management.
6.06 Executive order 11990 (Protection of Wetlands). The proposed action has
been evaluated under Executive Order 11990, Protection of Wetlands. The work
will not require dredging or filling of any wetlands. Also, the proposed work
will not produce hydrologic or salinity changes affecting any wetlands.
6.07 North Carolina Coastal Management Program. Evaluation of the proposed
work has resulted in a determination that it is consistent with the approved
Coastal Management Program of the State of North Carolina and local land use
plans. Concurrence with this determination is being requested from the North
Carolina Division of Coastal Management.
7.00 PUBLIC AND AGENCY INVOLVEMENT
7.01 scoping. on September 25, 1992, a scoping letter was sent to agencies,
interest groups, and the public to request identification of significant
resources, issues of concern, and recommendations for studies considered
necessary. Twenty-two letters of comment were received. The scoping letter
and a list of commentors are presented in Attachment B. The letters noted
support for the project, suggestions for beneficial uses of dredged material,
and concerns needing to be addressed. All were considered during the con-
tinuation of project planning and design. Further coordination has been
conducted with representatives of the USFWS, NMFS, NCDAH, and the NCDMF, as
has been noted throughout this report.
7.02 Fish and Wildlife Coordination. Project alternatives and issues related
to fish and wildlife resources have been coordinated with the USFWS throughout
planning and design (1991-1993) for the ocean bar deepening. The USFWS
provided a Planning Aid Report in October 1992, which identified fish and
wildlife resources in the project area and discussed potential project-related
impacts. Recommendations of that report were considered during project
development. On May 28, 1993 the USFWS provided a list of project-related
recommendations (Attachment C), pending submittal of their Draft Fish and
Wildlife Coordination Act Report. The following paragraphs present these
recommendations. The Corps of Engineers response to each is also provided.
The Service believes the following recommendations are necessary and should
be incorporated into project plans to minimize the expected adverse impacts
to fish and wildlife resources.
1. USFWS Recommendation. The channel deepening contract should state
clearly that blasting should be used as a last resort after it is shown and
documented that the rock cannot be removed with a cutterhead dredge. The
Corps has stated that they cannot require the contractor to complete the
19
deepening project without the use of blasting, even if blasting is not ab-
solutely necessary; however, the Corps' experimental rock removal has
demonstrated that the rock can probably be removed through dredging.
Therefore, to minimize unnecessary adverse impacts to public trust
resources, the Service prefers and recommends that the project be done by
dredging; however, we would consider the use of minimal amounts of blasting
if removal of material with a rock cutterhead dredge is demonstrated not to
be physically possible. In the latter case, specific additional mitigation
measures would be necessary as addressed in recommendations 2, 4, 5, 6, 7,
8, and 9.
w
Corps Response. The Corps clearly prefers that the work be accomplished by
dredging only. However, numerous factors affect the dredgeability of rock,
and we cannot confirm in advance that blasting will not be required. The
issue is not whether it is physically possible to dredge all the rock, but
whether it is realistic and cost-effective to dredge all rock, considering
excessive wear and tear on equipment, unduly slow production rates, and
possibly other factors. We will attempt to assure that no more rock is
blasted than is realistically required, and we will employ mitigative
measures as described in our responses below.
2. USFWS Recommendation. If blasting is necessary, measures should be
implemented to minimize the lethal range of blasts. Those measures should
include-:-drilling-holes-for-the--blasts;-stemming-the -blasts; using as low
velocity explosives as possible without diminishing effectiveness; using
instantaneous delays between rows of blasts; and keeping the number of
blasts per day and the total number of blasts to a minimum. The Corps'
draft description of project plans stated that these measures will be in-
cluded in the contract, and we support efforts in this regard.
Corps Response. The blasting contract will include provisions for drilling
holes for explosive charges, stemming the holes, using instantaneous delays
between rows of blasts, and limiting the total number of blasts to a maxi-
mum of 60. The contractor will be encouraged to use explosives having the
lowest detonation velocity that will allow a reasonable and cost-effective
production rate, given the other constraints noted.
3. USFWS Recommendation. Careful time-of-year planning and impact preven-
tative measures are necessary for deepening activities so as to avoid or
minimize impacts to sea turtles, migratory whales, West Indian manatees,
shortnose sturgeon, and other anadromous species, and estuarine dependent
larvae. Dredging and blasting time frames should be developed in coordina-
tion with the Service, the North Carolina Division of Marine Fisheries and
the National Marine Fisheries Service and will be specified in the final
report. The best time for blasting with regard to estuarine dependent
larvae and anadromous species may be the period November 1 through December
15. The National Marine Fisheries Service should be contacted regarding
the best time to conduct activities in order to avoid impacts to sea
turtles, marine mammals, and shortnose sturgeon. In order to avoid impacts
to the West Indian manatee, blasting activities should be avoided between
May through October.
20
Corps Response. It is anticipated that the proposed dredging work will re-
quire about 16 months for completion; therefore, it will span all seasons.
However, hydraulic pipeline dredging is not expected to produce any sig-
nificant adverse impacts, regardless of the season. The impact-preventive
measures incorporated in the blasting plan include a maximum limit of 60
blasts, so it may be possible to incorporate some seasonal planning into
the blasting program. However, our previous coordination with the USFWS,
NMFS, and the NCDMF indicates that some life stages of various marine, es-
tuarine, and anadromous species may be present in the project area during
each month of the year. This suggests that some minor impacts to these
populations could occur regardless of the time that blasting is conducted.
If the agencies can agree upon and recommend a preferred seasonal blasting
schedule, the Corps will consider it during the preparation of plans and
specifications for the work. Endangered and threatened species will be
given priority consideration in efforts to minimize blasting impacts.
Biological assessments evaluating potential project-related impacts on
these species are being prepared and will be coordinated with the USFWS and
NMFS. Any protective agreements reached through this coordination will be
incorporated into the contract for the proposed work.
4. USFWS Recommendation. The Corps should determine the expected lethal
radius out from the detonation site for all groups of organisms of concern,
and this information should be used to ensure that blasting is avoided when
large schools of fish are within the lethal range of the blast site or when
endangered or threatened species are within the lethal range of the blast
site. The lethal range will likely vary based on the type of explosive
used and the measures implemented and will vary for different species. The
Corps should consider requiring the contractor to use low velocity ex-
plosives because pressure increases are not as rapid as they are when high
velocity explosives are used, and fish are more likely to survive explo-
sions.
Corps Response. Potential lethal ranges have been determined and will be
considered when establishing any monitoring zones for the blasting program.
Efforts will be made to determine that no endangered or threatened species
are present in such monitoring zones when blasting is conducted.
Monitoring procedures for marine mammals (which surface for air and which
are large enough to be seen) and sea turtles (which can be successfully
trawled for detection and/or removal to other locations) are straightfor-
ward and can be effectively implemented. Monitoring for fish in an area of
more than 150 acres and water depths up to 40 feet is judged impractical
and infeasible, as is described in our response to item 6 on the next page.
Therefore, some incidental loss of fish is anticipated. The contractor
r will be encouraged to use an explosive of the lowest detonation velocity
consistent with the other elements of the blast plan.
5. USFWS Recommendation. If blasting occurs between May through October,
surveys should be made by at least two Service-approved and qualified ob-
servers from aircraft or watercraft, immediately prior to blasting, to
ensure that no West Indian manatees are within the lethal range of detona-
tion. If a manatee is present within the lethal range, blasting should be
postponed until the animal moves by its own will out of the impact zone.
Similar monitoring will probably be necessary for sea turtles, whales, and
21
dolphins. However, the National Marine Fisheries Service has jurisdiction
over these species and the shortnose sturgeon, and that agency should be
contacted regarding protection of the species.
Corps Response. Biological assessments evaluating potential project-
related impacts on endangered and threatened species (manatees, whales,
sea turtles, and shortnose sturgeon) are being prepared and will be coor-
dinated with the USFWS and NMFS. Any protective agreements reached through
this coordination will be incorporated into the contract for the proposed
work. It is anticipated that the observer program for these species would
also be applicable for other marine mammals, including dolphins. '
6. USFWS Recommendation. Immediately prior to blasting, the impact zone
should be surveyed.by qualified observers aboard a boat equipped with fish
finder echolocators or transducers. If large schools of fish are located
within the lethal range of the blast site, blasting activities should be
avoided until the fish move out of the lethal range.
Corps Response. Fish-finding technology has limited lateral range.
Monitoring for fish in an area of more than 150 acres and water depths up
to 40 feet is judged impractical and infeasible. Even when no fish are
detected in the part of the blast zone being surveyed, fish could enter
previously-surveyed areas of the blast zone without detection. Unless-
--numerous -boats with-fish f inders-were used simultaneously, it would be im-
possible to verify that the entire blast zone has no fish present at the
time of detonation. Even if a more reasonable monitoring procedure was
developed, questions would arise such as: (1) how large a fish school would
justify a delay, (2) how long a delay is reasonable, and (3) what if a
nightfall is approaching and further delay would encroach upon the time
necessary for post-blasting monitoring for endangered species. Overall,
this concept is not considered practical, and it would not result in effec-
tive fishery protection. Some incidental loss of fish is anticipated, but
such impacts are expected to be minor.
7. USFWS Recommendation. The Corps should analyze the possibility of using
sound as a fish deterrence in order to disperse fish away from the blasting
zone, should blasting be necessary. This method developed by Sonalysts,
Incorporated, has been successful in deterring alewives away from blasts
during blasting activities related to tunnel construction in Boston Harbor.
Corps Response. Sonalysts, Inc. has developed technology ("Fish Startle")
that uses underwater. transducers to emit high-frequency sound waves to
scare fish. Our conversations with Mr. Mike Curtin, Project Manager,
Sonalysts, Inc. indicate that their technology has been very successful at
several locations with several fish species, namely shad, herring, and
alewives. However, their technology involves sound emissions at specific
frequencies for specific fish species, and, at present, the details have
been worked out for only a limited number of species. It is, therefore,
not possible to purchase off-the-shelf technology for a wide variety of
species. Since this is developing technology, it has not been proven to
nor accepted by resource agencies as an alternative to other measures such
as monitoring. It is expensive to use (around $100,000 or more per month
to deploy from boats), and it has not been used in the open ocean. While
22
we believe that the technology could be very useful after further develop-
ment, wider application, and general agency acceptance, we do not feel that
it is timely for implementation in conjunction with this project.
D
•
8. USFWS Recommendation. A comprehensive post-blast monitoring plan should
be developed and implemented so that the species and numbers of organisms
killed by the blasts can be estimated. The monitoring plan should be
developed in coordination with the Service, the North Carolina Division of
Marine Fisheries, and the National Marine Fisheries Service and should in-
volve surveying the blasting impact area by boat and counting and
identifying dead or wounded organisms which float to the surface. Although
all dead organisms may not float to the surface immediately, this method
should give an indication of the extent of the impacts to finfish and other
organisms. Other monitoring may also be necessary.
Corps Response. We agree to work with the USFWS, NMFS, and NCDMF toward
the development of a post-blast monitoring plan.
9. USFWS Recommendation. Although it has been determined that the rock
dredged from the channel will likely be too small to be high value artifi-
cial reef material, rock removed by blasting may be of adequate size to
provide suitable reef habitat. Any material of appropriate size should be
tested to ensure it is free of contaminants and if acceptable quality,
should be used as artificial reef material. Such an effort should be
closely coordinated with the National Marine Fisheries Service and the
North Carolina Division of Marine Fisheries. The Corps should ensure that
all rock rubble created through blasting is removed from the ocean floor so
that it does not destroy trawling nets.
Corps Response. Rock cutterhead dredging is expected to produce rock too
small for good quality reef material. Any rock resulting from blasting
could be of better quality and, if suitable, will be made available to the
NCDMF for use in its Artificial Reef Program. This effort will continue to
be coordinated with the NCDMF and NMFS. Under USEPA's Ocean Dumping
Regulations and Criteria (40 CPR 227.13 (b)(1)), testing for contaminants
is not required for rock from coastal areas with strong currents. This ex-
clusion is allowed because contaminants are not usually associated with
coarse sediments from coastal areas of high current or wave energy. The
channel bottom is already irregular, due in part, to the uneven rock sur-
face there. The proposed work will require rock removal to a depth no
greater than elevation -41 feet mlw. Below that, the two-foot zone of al-
lowable overdepth will continue to remain irregular, as it is now.
10. USFWS Recommendation.. To protect nearby beach habitats, limit the
amount of sand removed from the littoral system by using suitable material
dredged from the channel for beach nourishment of eroding adjacent beaches,
rather than placing high quality sand offshore at the Ocean Dredged
Material Disposal Site. The Corps should determine the sediment budget of
the area and determine how deepening the channel will affect the sediment
budget.
23
Corps Response. The proposed work will have no effect on littoral
processes. It will begin at a point approximately 2 miles seaward from the
river mouth. This point is beyond the zone of littoral sand transport, so
adjacent beaches should be unaffected. Since no effects will occur in the
littoral transport zone, there will be no effect on the littoral sand
budget. The zone in which the work will occur is an area of weak currents
and shoaling that is characterized by fine sediments, i.e., silts and
clays. Silts and clays are not part of the littoral sediment budget.
7.03 Coordination of this Document. This Environmental Assessment /Finding of
No Significant Impact (EA/FONSI) is being provided to interested Federal,
State, and local agencies, as well the public for review and comment. After
any further coordination required as a result of comments received, the FONSI
will be signed prior to the initiation of the proposed action.
Recipients of this Assessment
Federal Agencies
Advisory Council on Historic Preservation
Center for Disease Control, Center for Environmental Health
Corps of Engineers, Norfolk District
Federal Emergency Management Administration
Federal HIghway-Administrat ion
Federal Maritime Commission
Fifth Coast Guard District
National Marine Fisheries Service, Habitat Conservation Division, Beaufort
Marine Fisheries Center
National Marine Fisheries Service, Southeastern Regional Office
National Park Service, National Maritime Initiative
National Park Service, Southeast Regional Office, Archaeology
U.S. Department of Agriculture, Forest Service, Area Director,
U.S. Department of Agriculture, Soil Conservation Service, State
Conservationist
U.S. Department of Commerce, NOAH, Ecology & Environmental Conservation
office
U.S. Department of Energy, Office of Environmental Compliance
U.S. Department of Housing and Urban Development
U.S. Department of Interior, Office of Environmental Affairs
U.S. Environmental Protection Agency, Office of Federal Activities
U.S. Environmental Protection Agency, Region IV, EIS Review Section
U.S. Environmental Protection Agency, Region IV, Environmental Policy
Section
U.S. Environmental Protection Agency, Region IV, Regional Administrator .
U.S. Fish and Wildlife Service, Asheville Field Office
U.S. Fish and Wildlife Service, Raleigh Field Office
24
State Agencies
N.C. State Clearinghouse
N.C. Division of Archives and History, Underwater Archaeology Unit
N.C. Department of Environment, Health, and Natural Resources
N.C. Division of Coastal Management
N.C. Division of Marine Fisheries
N.C. Office of Water Resources
N.C. Department of Transportation
N.C. National Estuarine Research Reserve
N.C. Sea Grant Program, Ft. Fisher
N.C. State Historic Preservation Officer
N.C. State Port Authority
f
N.C. Wildlife Resources Commission
Local Agencies
Brunswick County Manager
City Manager, Carolina Beach
City Manager, Southport
CAMA Officer, Brunswick County
CARA Officer, New Hanover County
CAMA Officer, Town of Carolina Beach
CAMA Officer, Town of Kure Beach
CAMA Officer, Town of Southport
Fayetteville Area Chamber of Commerce
Director of Public Works, City of Wilmington
New Hanover County Health Department
New Hanover County, Director of Engineering and Facilities
New Hanover County Engineer
New Hanover County Planning Department
New Hanover County Soil and Water Conservation District
North Carolina Council of Governments, Region O
North Carolina State Ports Authority, Assistant Port Manager
Wilmington Planning Department
Postmasters
Conservation Grouvs
Conservation Council of North Carolina
Izaac Walton League
National Audubon Society
National Wildlife Federation
North Carolina Coastal Federation
North Carolina Environmental Defense Fund
North Carolina Wildlife Federation
• Sierra Club
Libraries
Duke University Library
Librarian, North Carolina Department of Environment, Health
and Natural Resources
25
New Hanover County Law Library
New Hanover County Library
North Carolina Maritime Museum
North Carolina State Library
UNC-Wilmington Library
UNC-Chapel Hill Library
Elected Officials
Brunswick County, Board of Commissioners
Honorable John Codington
Honorable Lauch Faircloth, United States Senate
Honorable Karen Gottovi
Honorable Jesse Helms, United States Senate
Honorable Charles G. Rose, Representative in Congress
Honorable R. C. Soles, Jr.
New Hanover County, Board of Commissioners
Mayor, City of Wilmington
Mayor, Town of Carolina Beach
Mayor, Town of Kure Beach
Mayor, Town of Southport
Interested Businesses, Groups, and Individuals
8.00 POINT OF CONTACT
Any comments or questions regarding this EA/FONSI should be sent to Mr. John
Meshaw, CESAW-PD-E, U.S. Army Engineer District, PO Box 1890, Wilmington,
North Carolina 28402-1890. Telephone contact is [phone].
}
a

26
9.00 FINDING OF NO SIGNIFICANT IMPACT
No unacceptable adverse effects on geology and sediments, water resources,
marine and estuarine resources, terrestrial resources, wetlands and flood
plains, threatened and endangered species, cultural resources, esthetic and
recreational resources, recreational and commercial fishing, or socio-economic
resources are expected to occur as a result of the proposed improvements to
the Wilmington Harbor ocean bar channel. Based on the environmental assess-
ment which precedes, the proposed action will not significantly affect the
quality of the human environment; therefore, this action will not be the sub-
ject of an environmental impact statement.
s
DATE Walter S. Tulloch
Colonel, Corps of Engineers
District Engineer
V
27
10.00 REFERENCES
r
e

r
Bahen, J.J., Jr. 1993. Marine Advisory Agent, North Carolina Sea Grant
Program. Personal communication regarding commercial and recreational fish-
ing in the vicinity of Cape Fear.
Birkhead, W.A., B.J. Copeland, and R.G. Hodson. 1979. Ecological monitoring
in the Lower Cape Fear Estuary, 1971-1976. Report 79-1, Carolina Power and
Light Company, Raleigh, North Carolina. 292pp.
Carolina Power and Light Company (CP&L). 1980. Brunswick Steam Electric
Plant, Cape Fear Studies: Interpretive Report. Carolina Power and Light
Company, Raleigh, North Carolina.
Gaspin, J.B. 1975. Experimental investigations of the effects of underwater
explosions on swimbladder fish, I: 1973 Chesapeake Bay tests. NSWC/WOL TR
75-58.
Gaspin, J.B., M.L. Wiley, and G.B. Peters. 1976. Experimental investigations
of the effects of underwater explosions on swimbladder fish, II: 1975
Chesapeake Bay tests. NSWC/WOL TR 76-61.
Ippen, A.T. (ed.). 1966. Estuary and Coastline Hydrodynamics. McGraw Hill
Book Company, New York, NY.
Munday, D.R., G.L. Ennis, D.G. Wright, D.C. Jeffries, E.R. Mcgreer, and J.S.
Mathers. 1986. Development and evaluation of a model to predict effects of
buried underwater blasting charges on fish populations in shallow water
areas. Canadian Technical Report of Fisheries and Aquatic Sciences. 1418:x
+ 49 pp.
Nichols, P.R. and E.D. Louder. 1970. Upstream passage of anadromous fish
through navigation locks and use of the stream for spawning and nursery
habitat, Cape Fear River, North Carolina, 1962-66., U.S. Fish and Wildlife
Service, Circ. 352.
O'Keeffe, D.J. and G.A. Young. 1984. Handbook on the environmental effects
of underwater explosions. Naval Surface Weapons Center. NSWC TR 83-240.
Schwartz, F.J., W.T. Hogarth, and M.P. Weinstein. 1981. Marine and fresh-
water fishes of the Cape Fear River Estuary, North Carolina, and their
distribution in relation to environmental factors. Brimleyana No. 7:17-37.
July 1981.
Rasmussen, B. 1967. The effects of underwater explosions on marine life.
Bergen, Norway. 17 pp.
Walburg, C.H. and P.R. Nichols. 1967. Biology and management of the American
shad and status of the fisheries, Atlantic Coast of the United States, 1960.
U.S. Fish and Wildlife Service, Spec. Sci. Rpt.-Fish. No. 550. 35-38pp.
28
Wright, D.G. 1982. A discussion paper on the effects of explosives on fish and
marine mammals in the waters of the Northwest Territories. Can. Tech. Rep.
Fish. Aquat. Sci. 1052: v + 16 pp.
Young, G.A. 1991. Concise method for predicting the effects of underwater ex-
plosions on marine life. Naval Surface Warfare Center. NAVSWC MP 91-220.
22pp.
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ATTACHMENT A
SECTION 103 EVALUATION
MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
WILMINGTON, NORTH CAROLINA
F
June 1993
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
WILMINGTON, NORTH CAROLINA
EVALUATION PURSUANT TO SECTION 103
MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT OF 1972, AS AMENDED
1.0 PURPOSE
The U.S. Environmental Protection Agency's (EPA) Ocean Dumping
Regulations and Criteria (40 CFR 220-228) require in Part 225 that applica-
tions and authorizations for Dredged Material Permits under Section 103 of the
Marine Protection, Research, and Sanctuaries Act of 1972, as amended, for
transportation of dredged material for the purpose of dumping it in ocean
waters will be evaluated by the U.S. Army Corps of Engineers in accordance
with criteria set forth in Part 227. In accordance with those criteria, the
following is an assessment of transportation of dredged material from the
proposed deepening of the Wilmington Harbor ocean bar channel, for the purpose
of ocean disposal.
2.0 PROJECT DESCRIPTION
2.1 Existing Conditions - Wilmington Harbor Proiect. The Wilmington Harbor
Federal navigation project consists of a series of channels or "reaches" ex-
tending from the ocean bar channel at the mouth of the Cape Fear River to a
point above Wilmington, North Carolina (Figure 1). Specifically, the
authorized Wilmington Harbor project is 30.8 miles long and provides for an
entrance channel depth of 40 feet mean low water (m.l.w.) and 500 feet wide
from the Atlantic ocean through the ocean bar and entrance channels to
Southport, thence 38 feet deep and 400 feet wide, with increased widths at
bends, to the upper end of the anchorage basin at Wilmington. Additional
channels and turning basins are provided for at Wilmington. A dredging over-
depth of 2 feet is allowable for dredging inconsistencies throughout the
length of the channel and 1 foot of overdepth is required for vessel safety in
channel areas with rock substrate.
2.2 Existina Conditions - Wilmington Harbor Ocean Bar Channel. This Section
103 Evaluation deals specifically with the ocean bar channel portion of the
Wilmington Harbor project (also called Baldhead Shoal Channel). The ocean bar
channel extends seaward from the mouth of the Cape Fear River (Figure 2). The
ocean bar channel has been maintained by the Federal Government for well over
100 years. Its most recent improvements were constructed pursuant to a con-
gressional authorization to widen it from 400 feet to 500 feet and deepen it
from 35 feet to 40 feet m.l.w. This work was completed in 1973, but the
authorized project depth of 40 feet was not achieved due to rock obstructions
and bathymetric survey inaccuracies. The actual controlling depth of the
ocean bar channel for navigation "is 38 feet m.l.w.
2.3 Wilmington Harbor Maintenance Dredaing and Dredged Material Disposal. The
maintenance dredging requirements for the Wilmington Harbor navigation channel
are summarized in Table 1. Continuation of the operational capability of the
Wilmington Harbor navigation channel depends upon maintenance dredging.
Annual maintenance dredging is required at project extremes, the ocean bar and
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A-3
anchorage basin and approaches at Wilmington. Reaches or channels in between
those extremes require maintenance but generally less frequently and with less
volume of dredged material than the ocean bar channels or the anchorage basin
and approaches at Wilmington. The dredged material disposal methods for a
particular reach depend on characteristics of the dredged material, the
availability of disposal capacity, and the type of dredge equipment used.
In the early years of the Wilmington Harbor project, most of the material
dredged from the channel (other than the ocean bar) was deposited on the ad-
jacent river bottoms, using open water disposal by pipeline dredge. This
practice formed many of the islands and flats which are presently found ad-
jacent to the channel. Since 1972, the islands have been diked to reduce
adverse impacts on estuarine resources and shoaling by confining the dredged
sediments. Confined disposal area islands for channels including Big Island
to the ocean bar have reached their capacity and ocean disposal of that
material is now required. At the ocean bar, strong currents and often tur-
bulent seas do not generally allow the use of a pipeline dredge; therefore,
hopper dredges are generally used there with dredged material disposal in the
Wilmington ocean dredged material disposal site.
Annual maintenance dredging from 1988 through 1992 produced an average of
about 927,000 cubic yards of mixed sand, silt, and clay from Baldhead Shoal
Channel and the adjacent four upstream channel reaches (Smith Island Channel,
Caswell-Southport Channel, Southport Channel, and Battery Island Channel),
collectively. Maintenance of these five channels is accomplished by ocean-
going hopper dredges, and dredged material is placed in the Wilmington ocean
dredged material disposal site (ODMDS). Ocean-certified hydraulic pipeline
dredges are now also available to perform this work, although they have not
yet been used for routine maintenance dredging on this group of channels. The
ocean-certified pipeline dredge would place dredged material in the Wilmington
ODMDS either by direct pipeline of by scow or hopper barge.
2.4 Proposed Wilmington Harbor Ocean Bar Improvements. The 38-foot depth of
the river channel to the State Port facility cannot be fully utilized by
ocean-going vessels which must lightload and/or wait for high tide to deal
with the shortfall in channel depth at the ocean bar in combination with the
ocean wave climate and the risk posed by the rock bottom. Lightloading and/or
delays are very costly to shippers. The NCSPA has requested that the Corps of
Engineers provide the authorized project depth and appropriate overdepth at
the ocean bar to allow for full use of the river channels under normal tidal
conditions.
It is proposed to provide the authorized ocean bar channel depth of 40
feet m.l.w. from the intersection of Smith Island Channel (station 0+00)
seaward along the existing ocean bar channel alignment to the 40-foot contour
(station 305+00), a distance of about 30,500 feet or 5.8 miles (Figure 3). In
addition, 1 foot of overdepth would be required in rock areas and 2 feet of
overdepth would be allowable for dredging inconsistencies throughout the
length of the channel. The authorized channel depth already exists from sta-
tion 0+00 to station 125+00, so new work would be required only seaward from
station 125+00. Since the existing channel ends at station 240+00, the im-
proved channel will represent a seaward extension of about 6,500 feet.
Maintenance dredging of the improved channel will be accomplished using the
same dredging methods and disposal area described above. It is expected that
w.
A-4
maintenance dredging will continue to be required at a frequency of about once
per year and that the proposed channel modifications will increase the annual
maintenance dredging requirement by 128,000 cubic yards.
2.5 Proposed Construction Method. Based on bathymetric surveys taken just
prior to the 1992 maintenance dredging cycle, project construction will in-
volve the removal of approximately 1.6 million cubic yards of material from
the Wilmington Harbor ocean bar channel. That total is comprised of main-
tenance material (overburden that has accumulated in the dredged channel since
last dredging cycle) and new work material (sediment from channel areas that
have not previously been dredged). The following is a summary of the es-
timated maintenance and new work dredging quantities:
Location and Type of Dredging Ouantity (Cubic Yards)
Maintenance Dredging (Station 125+00 to 240+00) 709,700
New Work Dredging (Station 125+00 to 240+00)
Overburden (not rock) 24,300
Rock 551,000
New Wbrk Dredging (Station 240+00 to 305+00)
Overburden (not rock) 76,000
Rock 279.000
Total Maintenance 709,700
Total New Work Overburden 100,300 930,300
Rock 830.000
TOTAL DREDGING 1,640,000
Rock comprises about 830,000 cubic yards of the material to be dredged,
while the remainder is a mixture of sand, silt, clay, and a small amount of
shell fragments. Removal will be primarily by hydraulic pipeline dredge with
a rock cutterhead. Sediments will be delivered to the point of disposal
within the Wilmington ODMDS either by pipeline or by a surface vessel (scow,
barge, or hopper dredge). Prior to its removal, some rock may require drill-
ing and blasting due to a combination of factors that would prevent cost-
effective removal by dredging only. Such complicating factors may include
rock hardness, thickness, joint spacing, spacing and strength of planes of
weakness, orientation of the rock mass, and possibly other factors as well.
As a worst case, it is estimated that such non-dredgeable rock, if present,
comprises less than 14,000 cubic yards or less than 2 percent of all the rock
to be removed. After blasting, this rock could be removed by pipeline dredge
or bucket and barge.
2.6 Proposed Disposal of Dredged Material. Disposal of dredged material will
be primarily in the Wilmington ocean dredged material disposal site
(ODMDS)(Figure 4). The material will be placed within the most eastern quad-
rant of the ODMDS, which is most distant from the navigation channel to reduce
any potential navigation hazard posed by rock. Mounding of dredged material
will be controlled to assure at least 25 feet of vertical clearance for
navigation above it. The North Carolina Division of Marine Fisheries
(Artificial Reef Program) and the National Marine Fisheries Service were con-
sulted concerning the possible use of dredged rock for the construction of an
offshore fishing reef or augmentation of an existing reef. However, this con-
cept has limited applicability based on data from test excavations by a rock
A-5
cutterhead dredge at Baldhead Shoal Channel in March 1992. The rock produced
by the grinding action of the cutterhead was generally too small to provide
good quality reef construction material. It was estimated that only about 10
percent of the dredged rock was 8" diameter or larger. Also, the proposed new
work dredging will collect the rock along with the overlying sediments to
produce a mixture which would be even less suitable for reef construction. If
any rock requires blasting, the dredged material produced (at most ap-
proximately 14,000 cubic yards) may be somewhat better quality and, if
suitable for fishery reef construction, may be placed on an offshore site
managed by the North Carolina Division of Marine Fisheries pending required
environmental coordination. The material proposed for dredging does not con-
tain a sufficient amount of beach compatible sand to make beach disposal a
viable disposal alternative.
2.7 Proposed Construction Schedule. Project design is scheduled to be com-
plete and the project available for initiation of construction no later than
July 1994, subject to the availability of funds. It is estimated that the
work will require about 16 months for completion.
3.0 ENVIRONMENTAL DOCUMENTS ADDRESSING WILMINGTON HARBOR OCEAN BAR DREDGING
The following environmental documents address aspects of the Wilmington
Harbor ocean bar dredging program. These documents indicate the environmen-
tally acceptability of dredging and dredged material disposal methods for the
proposed Wilmington ocean bar channel improvements. Aspects of the proposed
new work which are different include excavation of dredged material from areas
that have not previously been dredged, the potential requirement for limited
rock blasting, and the potential transport and deployment of rock to an ar-
tificial reef site managed by the North Carolina Division of Marine Fisheries.
An environmental assessment and finding of no significant impact addressing
the environmental effects only for these different aspects proposed Wilmington
ocean bar channel dredging (item e. below) is being circulated to the public
at the same time this document is being submitted to EPA.
a. U.S. Army Engineer District, Wilmington. Environmental Assessment
and Finding of No Significant Impact, Excavation of Pits, Wilmington Harbor,
Baldhead Shoal Channel, Brunswick County, North Carolina, October 1991.
b. U.S. Army Engineer District, Wilmington. Environmental Assessment
and Finding of No Significant Impact, Maintenance Dredging in Wilmington
Harbor Ocean Bar Channels by Ocean-Certified Pipeline, or Bucket and Barge
Dredge with Disposal in the Wilmington Harbor Ocean Dredged Material Disposal
Site, August 1991.
C. U.S. Army Engineer District, Wilmington. Final Environmental Impact
Statement (FEIS). Long-Term Maintenance of Wilmington Harbor, North Carolina,
October 1989.
d. U.S. Environmental Protection Agency. Final Environmental Impact
Statement (FEIS), Savannah, GA, Charleston, SC, and Wilmington, NC, Ocean
Dredaed Material Disposal Sites Designation, October 1983.
A-6
e. U.S. Army Engineer District, Wilmington. Environmental Assessment
and Finding of No Significant Impact. Wilmington Harbor, N.C. - Ocean Bar
Channel Deepening, June 1993.
4.0 OCEAN DISPOSAL SITE
The Wilmington ODMDS was designated by EPA pursuant to Section 102(c) of
the Marine Protection, Research, and Sanctuaries Act of 1972, as amended, as
suitable for the ocean disposal of dredged material. The final rule was
promulgated by EPA on 02 July 1987 (FR Vol 52 No. 127), effective 03 August
1987. The Wilmington ODMDS has an area of about 2.3-square nautical miles.
Depths within the ODMDS range from 28 tp 46 feet below m.l.w. (based on a June
1992 and July 1992 bathymetric survey). The bathymetry is gently sloping from
north to south. Portions of the site have been used for many years for the
ocean disposal of dredged material from the Wilmington Harbor Federal naviga-
tion project and the Military Ocean Terminal, Sunny Point (MOTSU)(a Department
of the Army, Section 103 permitted facility). Approximately 1 million cubic
yards of dredged material from the Wilmington Harbor navigation channel and 1
million cubic yards from the MOTSU facility are presently ocean dumped in the
Wilmington ODMDS each year. Bathymetric surveys have indicated mounding at
some locations within the ODMDS where disposal activities have taken place.
The potential effects of the disposal of dredged material within the
Wilmington ODMDS were assessed in the FEIS, Savannah, Georgia; Charleston,
South Carolina; and Wilmington, North Carolina, Ocean Dredged Material Site
Designation, October 1983, prepared by the U.S. EPA.
The State of North Carolina has concurred with EPA's determination that
the Wilmington ODMDS site designation is consistent with the approved Coastal
Management Program of North Carolina. The discharge of dredged material in
the Wilmington ODMDS takes place outside the 3-nautical-mile limit of the ter-
ritorial sea and is regulated under the Marine Protection, Research, and
Sanctuaries Act of 1972, as amended. A Section 401 Water Quality Certificate
under the Clean Water Act of 1977, as amended, is not required.
The site designation final rule indicates that the National Marine
Fisheries Service and the U.S. Fish and Wildlife Service have concurred with
EPA's conclusion that the designation of the site for dredged material dis-
posal will not affect the endangered species under their jurisdiction.
Significant adverse effects of previous authorized disposal in the
Wilmington ODMDS have not been observed. As discussed previously, mounding of
dumped dredged material occurs within the Wilmington ODMDS. The use of the
Wilmington ODMDS is managed to prevent persistent mounding from becoming a
hazard to navigation.
i
5.0 SECTION 103 DISPOSAL CRITERIA COMPLIANCE EVALUATION
This evaluation addresses the transportation for the purpose of ocean
disposal material dredged to provide and maintain the authorized channel depth
of 40 feet m.l.w. within the Wilmington Harbor ocean bar channel (Baldhead
Shoal channel). As discussed previously, the dredging will involve the
removal of maintenance material (overburden shoal material that has accumu-
lated since the last dredging cycle) and new work material (sediment from
A-7
channel areas that have not previously been dredged). Approximately 1.6 mil-
lion cubic yards of material will be removed from the Wilmington Harbor ocean
bar channel and transported to the Wilmington ODMDS for disposal.
Part 227 Criteria for the Evaluation of Permit Applications for Ocean Dumving
of Materials
Subpart A - General
Part 227.1 Applicability
The proposed transportation of this dredged material for disposing of it
in ocean waters was evaluated to ensure that the proposal would not un-
reasonably degrade or endanger human health, welfare, or amenities or the
marine environment, ecological systems, or economic potentialities. In making
this determination, the criteria established by the Administrator, EPA, pur-
suant to Section 102(a) of the Marine Protection, Research, and Sanctuaries
Act of 1972, as amended, were applied. In addition, navigation, economic, and
industrial development, and foreign and domestic commerce of the United
States, and the availability of other alternatives were considered in deter-
mining the need to dispose of the dredged material in ocean waters.
Part 227.2 Materials Which Satisfy The Environmental Impact Criteria of
Subpart B
The material proposed for ocean dumping satisfies the environmental im-
pact criteria set forth in Subpart B. The information to follow supports that
determination. In addition, the information to follow indicates that there is
a need for ocean dumping in -accordance with Subpart C; there are no unaccep-
table adverse effects on aesthetic, recreational, or economic values in
accordance with the criteria set forth in Subpart D; and, there are no unac-
ceptable adverse effects on other uses of the ocean as determined in
accordance with criteria established in Subpart E.
Part 227.3 Materials Which Do Not Satisfy The Environmental Impact Criteria
of Subpart B
Not applicable.
Subpart B - Environmental Impact
Part 227.4 Criteria for Evaluatioa Environmental Impact
The proposed transportation of this dredged material for disposing of it
in ocean waters was evaluated to determine that the proposal would not un-
reasonably degrade or endanger human health, welfare, or amenities, or the
marine environment, ecological systems, or economic potentialities. In making
this determination, the criteria established by the Administrator, EPA, pur-
suant to Section 102(a) of the Marine Protection, Research, and Sanctuaries
Act of 1972, as amended, were applied.
A-8
Part 227.5 Prohibited Materials
The dredged material proposed for ocean dumping is not known to include
prohibited materials as defined in this section.
Part 227.6 Constituents Prohibited as Other Than Trace Materials
Wilmington Harbor ocean bar channel sediments proposed for ocean dis-
posal, associated with ocean bar deepening, both maintenance and new work
(deepening) materials as described previously, have been evaluated to deter-
mine acceptability for ocean disposal in accordance with EPA's Ocean Dumping
Regulations and Criteria.
Maintenance materials from the ocean bar channel (fine-grained sediments)
were chemically and biologically tested in 1992 using methods described in
Evaluation of Dredged Material Proposed for Ocean Disposal (Testing Manual).
February 1991. The tests indicate that these sediments meet the criteria of
the EPA Ocean Dumping Regulations and Criteria (40 CFR 220-229) and are,
therefore, acceptable for transportation for ocean dumping under Section 103
of the Marine Protection, Research, and Sanctuaries Act of 1972, as amended.
EPA, Region IV, concurred, by letter dated December 31, 1992, that this
material was suitable for disposal for one dredging cycle, with general con-
currence pending completion of the sediment testing data package for the
entire Wilmington Harbor Federal navigation project.
The new work dredged materials resulting from the proposed ocean bar
deepening, those beneath the maintenance materials and those containing rock,
were not chemically and biologically tested. However, with regard to con-
taminants, the new work materials are believed to be similar to the
maintenance materials tested or even less affected by anthropogenic con-
taminants due to their deeper and more isolated locations. The coarse rock
sediments from a coastal inlet area with strong currents are environmentally
acceptable for ocean dumping without testing (40 CFR 227.13 (b)(1)). Also the
new work materials which are not rock, are"likely similar to the substrate of
the Wilmington ODMDS and, by being deeper than 38 feet m.l.w. in areas that
have been historically more shallow than those depths, have likely been
removed from known and historic sources of pollution. This condition provides
reasonable assurance that the new work ocean bar materials have not been con-
taminated by pollution (40 CFR 227.13 (b)(3)).
Based on the sediment evaluations conducted, the Wilmington Harbor ocean
bar channel sediments both the maintenance and new work Wilmington Harbor
ocean bar dredged materials do not contain prohibited constituents including
the following as other than trace contaminants: organohalogen compounds, mer-
cury and mercury compounds, cadmium and cadmium compounds, oil and grease, and
known carcinogens, mutagens, and teratogens.
Tier I - Evaluation of Existina Information
The results of existing chemical and biological evaluations of Wilmington
Harbor Federal navigation project dredged materials were reviewed. A summary
of 1978-1989 sediment test data for Wilmington Harbor and MOTSU ocean dredged
material disposal is presented in Table 2. The general sample locations for
these analyses are shown in Figure 5. The reports from which this data was
extracted are the following:
A-9
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A-10
EG and G, Bionomics. 1978. Laboratory Evaluation of the Toxicity of Material
to be Dredged from the Outer Ocean Bar of the Cape Fear River, N.C. Prepared
Under Contract to the U.S. Army Corps of Engineers, Wilmington District.
Jones, Edmunds, and Associates, Inc. 1979. Grain Size Analysis, Bioassays,
and Bioaccumulation Potential Assessment, Access Channels and Anchorage
Basins Military Ocean Terminal, Sunny Point, N.C. Prepared Under Contract to
the U.S. Army Corps of Engineers, Wilmington District.
Jones, Edmunds, and Associates, Inc. 1980. Grain Size Analysis, Bioassays,
and Bioaccumulation Potential Assessment, Smith Island and Baldhead Shoal
Channels, Wilminaton Harbor, N.C. Prepared by Under Contract to the U.S. Army
Corps of Engineers, Wilmington District.
U.S. Army Corps of Engineers, Wilmington District. 1986. Environmental
Assessment, Maintenance Dredging with Clamshell Dredge and Ocean Dumpina, Keg
Island to Snow Marsh Channels, Wilmington Harbor, N.C., November 1986.
Appendices A and B Summarizes Chemical and Biological Analyses of Keg Island
Channel Sediments. Unpublished data provided by New York Testing
Laboratories, Inc. Under Contract to Wilmington District.
U.S. Environmental Protection Agency. 1989. Bioloaical and Chemical
Assessment of Sediments From Proposed Dredge sites in military Ocean Terminal
Sunny Point, North Carolina, Prepared by Environmental Research Laboratory,
Gulf Breeze, FL. Under Contract to the U.S. Army Corps of Engineers,
Wilmington District.
U.S. Environmental Protection Agency. 1989. Studies With Sediment From the
Proposed Wilmington Harbor Passing Lane North Carolina, and Representative
Marine Organisms, Prepared by Environmental Research Laboratory, Gulf Breeze,
FL. Under Contract to the U.S. Army Corps of Engineers, Wilmington District.
Contaminants of concern were identified based on the review of existing
data and coordination with environmental management agencies of the State of
North Carolina. A list of contaminants of concern as well as a Tier III sam-
pling design were closely coordinated with EPA, Region IV.
Tier III - Biological and Chemical Testin
Wilmington Harbor ocean bar maintenance sediment samples for chemical and
biological evaluations were collected 30 June 1992 from stations indicated in
Figures 6 and 7. At each site, BSCMA (Baldhead Shoal channel maintenance) and
WHREF (Wilmington ODMDS reference), five surface grab samples were taken and
later composited into a single sample representing a test treatment for
r biological and chemical testing. The results of the Wilmington Harbor ocean
bar Tier III sediment evaluations are provided in Ecological Evaluation of
Proposed Dredged Material From Wilmington Harbor, North Carolina, December
1992. The results are summarized in the following paragraphs.
A-11
Physical Characteristics
Based on the physical characteristics described in Table 3, the
Wilmington Harbor ocean bar maintenance dredged materials do not meet the ex-
clusion criteria of part 227.13(b) and must, therefore, be tested in
accordance with part 227.13(c).
Table 3. Grain Size Analyses - MPRSA Testing of Wilmington Harbor Ocean Bar.
Sediments collected 30 June 1992.
% Coarser By Weight
Sand* Silt Clay
>0.0625 mm >0.0039 mm <0.0039 mm Specific Total
Sample Site <0.0625 mm Gravity Solids% TOC%
BSCMA 16 41 43 2.78 31.35 2.78
WHREF 98 00 02 2.67 NA NA
Note: NA - No analysis
* - Wentworth classification used
BSCMA - Baldhead Shoal Channel Maintenance or Wilmington Harbor ocean
bar maintenance
WHREF Wilmington Harbor Reference Sediment
Bioassays
Suspended Particulate Phase (SPPI and Solid Phase (SP) Bioassavs. There
was no evidence of significant acute toxicity as determined through water
column (suspended particulate phase - SPP) and deposited sediment (solid phase
-SP) exposures to Wilmington Harbor ocean bar maintenance sediments. The
results of these bioassays are summarized in Tables 4 through 6. Thus, ocean
disposal of this material will not exceed the limiting permissible concentra-
tion (LPC). These toxicity test were performed using approved test marine
organisms.
Table 4. Results of SPP bioassays for Wilmington Harbor ocean bar (Baldhead
Shoal channel) maintenance sediments (BSCMA).
% Surv. % Surv. % Surv. % Surv.
Species 0 % SPP 10 % SPP 50% SPP 100% SPP
Menidia bervllina 100.0 100.0 100.0 100.0
Mysidopsis bahia 100.0 100.0 98.0 94.0
Lytechinus pictus 91.0 91.2 96.8 80.9
Note: % Surv. (% Survival) - Mean of 5 replicates
Number of organisms at Beginning of Test:
Menidia bervllina - 10
Mysidonsis bahia - 10
Lvtechinus pictus - stocking density target of 250 larvae

A-12
Table 5. Results of 10-day SP bioassays.
% Surv. % Surv. % Surv. % Surv.
Species Control 1 Control 2 WHREF BSCMA
Amvelisca abdita* 44.0 63.0 47.0 41.0
Rhevoxinius abronius 100.0 88.0 99.0 90.0
Nereis virens 93.0 NA 96.0 97.0
Note: * Amvelisca abdita test control data not acceptable. Test rejected.
NA - only one control was used for N. virens bioassay
% Surv. (% Survival) - Mean of 5 replicates
Number of Organisms at Beginning of Test:
Amvelisca abdita - 20
Rhenoxinius abronius - 20
Nereis virens - 20
Table 6. Results of 28-day SP bioassays
for tissue bioaccumulations).
Surv. % Surv.
Species Control WHREF
Nereis virens 88.0 90.0
Macoma nasuta 92.8 94.4
Note: % Surv. (% Survival) -
Number of Organisms at
Nereis virens - 20
Macoma nasuta - 25
Bioaccumulation
(used principally to obtain samples
% Surv.
BSCMA
90.0
97.6
Mean of 5 replicates
Beginning of Test:
The potential for bioaccumulation of contaminants in the Wilmington
Harbor ocean bar maintenance sediments was evaluated through 28-day solid
phase tests using Macoma nasuta and Nereis virens. The tissues were tested
for metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated
biphenyls (PCBs). This list of target analytes or contaminants of concern, in
tissues, was determined after review of sediment analyses and following coor-
dination with EPA, Region IV. The sediment analyte list included: metals,
PAHs, pesticides, PCBs, dioxins, furans, organotins, phthalates, and phenols.
Animal tissues exposed for 28 days to Wilmington Harbor ocean bar sedi-
ments and reference sediments showed no statistically significant difference
for any contaminant for the polychaete Nereis virens and no statistically sig-
nificant difference for any contaminant except lead for the clam Macoma nasuta
(metals bioaccumulation reported in Table 7).
LPC compliance with respect to bioaccumulation is based, in the absence
of comparisons with Food and Drug Administration (FDA) Action Levels for
Poisonous or Deleterious Substances in Fish and. Shellfish for Human Food for
the contaminants of concern, on statistical comparisons of the tissue con-
taminant concentration of organisms exposed to Wilmington Harbor ocean bar
maintenance and reference sediments. Additionally, paragraph 6.3 of the 1991
Testing Manual provides factors which are used to assess LPC compliance.
A-13
Table 7. Mean concentrations of metals in tissues of M. nasuta and N. virens
after 28-day bioaccumulation exposure. Samples collected 30 June 1992.
Bold and underlined indicates that a compound was significantly (p=0.05)
elevated in BSCMA relative to the reference WHREF.
Units are mg/kg dry weight (ppm):
M. nasuta N. virens M. nasuta N. virens
Metal / method BSCMA BSCMA WHREF WHREF
Ag GFAA 0.149 0.093 0.132 0.146
As GFAA 26.5 25.1 24.8 23.6
Be ICP/MS 0.04 0.002 0.007 0.002
Cd ICP/MS 0.296 0.335 0.232 0.364
Cr ICP/MS 3.8U 3.4U 3.8U 3.6
Cu ICP/MS 9.49 8.64 7.19 9.62
Hg CVAA 0.092 0.092 0.105 0.109
Ni ICP/MS 3.42 1.21 3.00 1.17
Pb ICP/MS 1.189 1.04 0.851 0.925
Sb GFAA 0.06U 0.06U 0.06U 0.06U
Se GFAA 2.00 1.43 1.66 1.32
T1 ICP/MS 30.6 13.0 38.9 18.0
Zn ICP/MS 83.0 190.7 75.0 156.8
Notes:
U - Analyte was not present above level of associated value
NA - No analysis
GFAA - graphite furnace atomic absorption analysis
ICP/MS - inductively coupled plasma/mass spectroscopy
CVAA - cold vapor atomic absorption
Based on the following evaluation, using those factors, the Wilmington Harbor
ocean bar maintenance and sediments meet the LPC for bioaccumulation and com-
ply with the bioaccumulation aspects of the Ocean Dumping Regulations and
Criteria.
Number of species and number of contaminants for which bioaccumulation was im-
portant (statistically greater than reference).
Statistically significant bioaccumulation of only one contaminant (lead)
was detected. There was only one species, Macoma nasuta, in which bioac-
cumulation from Wilmington Harbor ocean bar maintenance sediments was
statistically greater than bioaccumulation from the reference sediment. Tissue
analyses for pesticides, phenols and phthalates, organotins, and dioxins and'
furans were not conducted. The bulk sediment analyses indicated that those
contaminants would likely not be bioaccumulated.
A-14
Magnitude by which bioaccumulation in test sediments exceed reference.
The mean tissue lead concentrations were 1.189 mg/kg and 0.851 mg/kg dry
weight for clams exposed to the Wilmington Harbor ocean bar and reference
sediments, respectively. Thus, the magnitude by which lead concentration in
clams exposed to Wilmington Harbor ocean bar maintenance sediments exceeded
those exposed to reference sediments were small, 0.338 mg/kg (ppm) dry weight.
The lead enhancement in the tissues of M. nasuta exposed to Wilmington Harbor
ocean bar sediments versus reference sediments was 1.4 (1.189/0.851). The
clams tested normally regulate lead and other metals within an enhancement
factor of 2.2 (Word, pers. comm. 1992 ). Therefore, the bioaccumulation seen
may be the result of the biology of the species rather than bioaccumulation of
contaminants.
In order to assess the magnitude of lead bioaccumulation reported, the
tissue concentrations of metals contaminants in tissues of organisms exposed
to Wilmington Harbor ocean bar maintenance sediments (Table 7) were compared
to those reported for mollusks in the NOAA National Status and Trends Program
(NSTP) for Environmental Quality, Mussel Watch Project, 1986-1988 (NOAA 1989).
The Wilmington Harbor ocean bar test organisms tissues were compared to oyster
and mussel tissues from 57 coastal and estuarine sites in the eastern United
States (while the program includes 177 sites nationally, tissues from
eastcoast organisms were chosen for this comparison). The comparison sum-
marized in Table 8 indicates that the accumulation of lead in tissues of
mollusks exposed to Wilmington Harbor ocean bar maintenance sediments was not
higher than most in-situ tissue samples from eastern seacoast Mussel Watch
locations. The Mussel Watch sites were selected to be representative of their
surroundings, avoiding small scale patches of contamination and point source
discharges.
Table S. Comparison of tissue lead concentrations following exposure to BSCMA
sediments and those reported in tissues of in-situ mollusks reported in the
National Oceanic Atmospheric Administration (NOAA) Status and Trends Mussel
Watch Program (NOAH 1989).
. NOAA Sites - Atlantic Coast Only (ME to FL)
NOAA*
BSCMA M. edulis &
M. nasuta C. virainica
ma/ka ma/ka
Lead (Pb) 1.189 2.73 (1986)
3.47 (1987)
3.20 (1988)
R
No.
N
49
51
54
NOAA Sites with Data
:)AA SITES > BSCMA) % NOAA Sites > BSCMA
(28 > BSCMA) 57%
(29 > BSCMA) 57%
(32 > BSCMA) 59%
NOAA Site CFBI (Cape Fear Battery Island)
C. virginica
0.27 (1986)
0.24 (1987)
0.19 (1988)
Notes: * Mean of all sites for which data was reported. Sites reported as
Non-detected were computed as 0 mg/kg.
A-15
The NOAA Status and Trends Program also provides insight with regard to
the magnitude of contaminants of concern available for bioaccumulation in the
sediments tested (NOAA 1991). As stated previously, 177 coastal and estuarine
sites were surveyed nationwide. The 1991 NSTP Summary, which analyzed and
summarized 1984-1987 data, reported the survey wide geometric mean of 43 mg/kg
dry weight for lead in sediment. The 1991 Summary identified a "high value"
for sediment lead concentration at 89 mg/kg dry weight and the geometric mean
at 43 mg/kg dry weight. The "high record was identified as exceeding the
survey mean + 1 standard deviation of the lognormal distribution. The term
"high" was used to identify sediments heavily affected by human activity - not
necessarily of biological significance. Table 9 indicates that BSCMA sedi-
ments contained more lead contaminant than the reference sediment and both had
lower lead concentrations than the geometric mean or "high value" reported in
the NOAA Status and Trends program.
Table 9. Summary of metals concentrations in sediment samples - MPRSA testing
of BSCMA sediments. Sediments collected 30 June 1992.
Units are mg/kg dry weight (ppm) except as noted:
Metal / method BSCMA WHREF
Ag GFAA 0.03U 0.03U
As GFAA 24.3 2.71
Be ICP/MS 1.10 0.16
Cd ICP/MS 0.36 O.OlU
Cr ICP/MS 63.2 12.1
Cu ICP/MS 13.6 1.34
Hg CVAA 0.046 0.001U
Ni ICP/MS 15.6 1.05
Pb ICP/MS 20.4 4.28
Sb GFAA 0.27 0.16U
Se GFAA 0.50 0.13U
T1 ICP/MS 0.31 0.07
Zn ICP/MS 60.3 8.92
Units are ma/ka dry weight
TKN (351.4) 3060 55.0
Cyanide (335.2) 0.032U 0.011U
Oil and Grease 372.0 184.0
(413.2)
AVS (moles/g dry) 16.70 0.019
TOC (%) 2.26 2.44
Notes:
U - Analyte was not present above level of associated value
NA - No analysis

GFAA - graphite furnace atomic absorption analysis
ICP/MS - inductively coupled plasma/mass spectroscopy
CVAA - cold vapor atomic absorption
TKN (351.4); Cyanide (335.2); and oil and Grease(413.2) - EPA method in (j.
No current or widely accepted criteria exist for sediment lead concentra-
tions. However, Long and Morgan (1990) and McDonald (1992) have suggested
"yardstick" concentrations of 35.0 mg/kg dry weight and 42 mg/kg dry weight,
A-16
respectively, below which no biological effects would be expected to occur
(ER-L and TEL, respectively, as noted in the references). Wilmington Harbor
ocean bar maintenance sediments (BSCMA) had a lead concentration of 20.4 mg/kg
dry weight (Table 9). Thus, the Wilmington Harbor ocean bar sediments tested
did not exceed these suggested criteria with respect to lead.
Part 227.7 Limits Established for Specific Wastes or Waste Constituents
The dredged material to be ocean dumped does not exceed the limits set
forth for the designated specific wastes or waste constituents listed in this
section.
Part 227.8 Limitations on the Disposal Rates of Toxic Wastes
No toxic wastes will be dumped exceeding the limiting permissible con-
centration as defined in 40 CFR Part 227.27.
Part 227.9 Limitations on Ouantities of Waste Materials
The quantities of dredged material to be dumped will not cause long-term
damage to the marine environment or to amenities.
Part 227.10 Hazards to Fishing, Navigation, Shorelines, or Beaches
Repeated dredged material disposal at one location within the ODMDS may
cause mounding of the deposited material. Substantial mounding may be con-
sidered a hazard to navigation. The Wilmington Harbor ocean bar channel is
dredged to an authorized depth of -40 feet m.l.w. As the channel is dredged
through the flood tide delta or ocean bar, depths less than -40 feet m.l.w.
occur adjacent to the channel. Additionally, Frying Pan shoals lie to the
east of the disposal area. Accordingly, ships approaching this area are ap-
proaching shoal waters and do so with caution. The disposal area appears on
NOAA NOS navigation charts.
The placement of dredged material from the proposed Wilmington Harbor
ocean bar channel deepening will be localized within the most eastern quadrant
of the ODMDS, which is most distant from the navigation channel to reduce any
potential navigation hazard posed by rock. Mounding of dredged material will
be controlled to assure at least 25 feet of vertical clearance for navigation
above it. The Wilmington ODMDS will provide ample capacity for dredged
material disposal without significant mounding impacts.
The proposed ocean dumping will not cause unacceptable interference with
fishing or produce unacceptable conditions on shorelines or beaches. The
material proposed for ocean dumping is fine-grained material and not suitable
• for direct placement on shorelines as beachfill material.
Part 227.11 Containerized Wastes
No Containerized wastes are to be dumped.
A-17
Part 227.12 Insoluble Wastes
The dredged material proposed for ocean dumping consists of naturally oc-
curring sediment materials. These materials are compatible with the ocean
environment of the ODMDS. The majority of the sediments found in the
Wilmington Harbor ocean bar channel project area are principally fine-grained,
i.e., silt, sandy silt; and silty sand with some clay and peat. Localized
areas of coarser sands, shell fragments, and limestone rubble/fragments also
occur in the project site. Fine-grained materials generally overlay coarser
materials if coarse-grained materials are present.
Part 227.13 Dredged Materials
Wilmington Harbor ocean bar maintenance dredged materials proposed for
ocean dumping have been evaluated in accordance with EPA's Ocean Dumping
Regulations and Criteria (40 CFR 220-229) using techniques described in
Evaluation of Dredged Material Proposed for Ocean Disposal (Testing Manual)February 1991. The sampling design was closely coordinated with EPA, Region
IV and included bulk sediment analyses, bioassays, and bioaccumulation evalua-
tions. The results of these sediment evaluations are reported in Ecological
Evaluation of Proposed Dredged Material From Wilmington Harbor North
Carolina, Final Report. December 1992. The test results indicate that the
dredged materials resulting from the proposed Wilmington Harbor ocean bar
channel deepening are acceptable for ocean disposal under Section 103 of the
Marine Protection, Research, and Sanctuaries Act of 1972, as amended.
The new work dredged materials resulting from the proposed ocean bar
deepening, those beneath the maintenance materials and those containing rock,
were not chemically and biologically tested. However, with regard to con-
taminants, the new work materials are believed to be similar to the
maintenance materials tested or even less affected by anthropogenic con-
taminants due to their deeper and more isolated locations. The coarse rock
sediments from a coastal inlet area with strong currents are environmentally
acceptable for ocean dumping without testing (40 CFR 227.13 (b)(1). Also the
new work materials which are not rock, are likely similar to the substrate of
the Wilmington ODMDS and, by being deeper than 38 feet m.l.w. in areas that
have been historically more shallow, than those depths, have likely been
removed from known and historic sources of pollution. This condition provides
reasonable assurance that the new work ocean bar materials have not been con-
taminated by pollution (40 CFR 227.13 (b)(3)).
Subpart C - Need for Ocean Dumping
Part 227.14 Criteria for Evaluatina the Need for Ocean Dumping and
Alternatives for Ocean Dumping
A determination of the need for the proposed ocean dumping was made on
the guidelines specified in 40 CPR Part 227 Subpart C.
A-18
Part 227 15 Factors Considered in Determination of Need for Ocean Dumping
a. Degree of treatment useful and feasible for the waste to be ocean dumped:
No treatment for the dredged material to be ocean dumped is needed or
feasible. The dredged material is naturally occurring, sedimentary material.
b. Raw materials and manufacturing or other processes resulting in waste:
Not applicable.
% c. Other alternatives:
1. (a) Landfill (diked upland disposal). No long-term, environmentally
acceptable, upland, dredged material disposal areas are currently available
for Wilmington Harbor ocean bar materials. The dredging takes place in the
ocean beyond the mouth of the Cape Fear river. Ocean-going hopper dredges or
ocean-certified pipeline dredges must be used. Considering the communities
present along the Atlantic Ocean beaches and shores of the lower portion of
the Cape Fear River (at the mouth of the river), large diked upland disposal
facilities for large volumes of fine-grained maintenance materials would not
be environmentally acceptable. Accordingly, ocean disposal is the only long-
term dredged material disposal option available for maintenance dredging at
the Wilmington Harbor ocean bar.
1. (b) Beachfill. Most of the dredged materials from the proposed
Wilmington Harbor ocean bar project (maintenance and deepening) is mixed sand,
silt, clay and rock and is generally not compatible with existing beach sands.
The Wilmington District, U.S Army Corps of Engineers has evaluated the
hydraulic pipeline dredging and placement of sand from the channels at mouth
of the Cape Fear river to the beaches at Baldhead Island (USACE, 1989a and
1989b). That study indicated that only portions of Wilmington Harbor ocean
bar channel nearest Baldhead Island would the dredged material be suitable for
beach placement from a sediment materials and an economical pumping distance
perspective. Higher costs would be incurred by beach placement of those ac-
ceptable materials and ocean disposal of the remainder as compared to disposal
of all the material within the Wilmington ODMDS (USACE 1989a).
2. Well injection. Not applicable.
3. Incineration. Not applicable.
4. Spread material over the open ground. See 1. (a) and 1. (b) above.
5. Recycling of material for reuse. The large volumes of fine-grained
dredged materials produced each year (approximately 1 million cubic yards),
• the chloride content of the sediments dredged from marine conditions, and the
high water content of the dredged material make significant reuse of this
material unlikely.
6. Additional biological, chemical, or physical treatment of inter-
mediate or final waste. Not applicable.
A-19
7. Storage. The temporary storage of dredged materials from the
Wilmington Harbor ocean bar channel for later beneficial use is not feasible
due to the large volume of sediments that are annually dredged from the
facility. No economic or environmental advantages are obtained with this
storage option over alternatives l.a. and l.b. on the previous page.
d. Irreversible or irretrievable consequences of the use of alternatives to
ocean dumping: No environmentally acceptable or economically feasible alter-
natives to ocean dumping are available for Wilmington Harbor ocean bar
materials. Land disposal would dedicate large upland areas for that use.
Those upland habitats would be permanently altered.
Part 227.16 Basis For Determination of Need for Ocean Dumvina
See responses to Part 227.15 and the following:
1. There are no practical improvements which can be made in process
technology or overall waste treatment to reduce the adverse impacts of the
waste on the total environment.
2. There are no practical alternative locations and methods of disposal
or recycling available which have less environmental impact or potential risk
to other parts of the environment than ocean dumping.
Waterborne transportation to the port of Wilmington is dependent on the
maintenance of navigable conditions in the harbor.
Subpart D. Impact of the Proposed Dumping on Aesthetic, Recreational, and
Economic Values
Part 227.17 Basis for Determination
The impact of the proposed dumping on aesthetic, recreational, and
economic values of the ocean environment were evaluated according to factors
in 40 CFR Part 227 Subpart D.
Part 227.18 Factors Considered
The following factors were considered in the assessment of the impacts of
the proposed ocean dumping on aesthetic, recreational, and economic values of
the marine environment.
a. Nature and extent of present and potential recreational and commer-
cial use of areas which may be affected by the proposed dumping: The proposed
ocean dumping will not affect present or potential recreational or commercial
uses of the marine environment.
b. Existing water quality, and nature and extent of disposal activities,
in areas which might be affected by the proposed dumping: The disposal of
dredged material will locally and temporarily increase water column turbidity.
The suspended sediment material is expected to quickly settle to the bottom
following release from the dredge. This temporary increase in turbidity is
not expected to have adverse impacts on aesthetic, recreational, and economic
values of the marine environment including ocean waters, inshore waters,
beaches, and shorelines.
M

A-20
c. Applicable water quality standards: Applicable water quality stan-
dards in the ocean disposal area will not be contravened.
d. Visible characteristics of the materials which could result in unac-
ceptable aesthetic nuisance in recreational areas: See response to Part
227.18 (b).
e. Presence in the material of pathogenic organisms which may cause a
public health hazard either directly or through contamination of fisheries or
shellfisheries: There is no known presence of pathogenic organisms in sedi-
ment materials dredged from the Wilmington Harbor ocean bar.
f. Presence in the material of toxic chemical constituents released in
volumes which may affect humans directly: The dredged materials proposed for
ocean dumping do not contain chemical constituents which could be released in
volumes that may adversely affect humans. The dredged material is environmen-
tally acceptable for ocean dumping according to criteria established in EPA's
Ocean Dumping Regulations and Criteria.
g. Presence in the material of chemical constituents which may be bioac-
cumulated or persistent and may have adverse effect on humans directly or
through food chain interactions: Sediments dredged and proposed for ocean
dumping during the proposed Wilmington Harbor ocean bar maintenance and harbor
deepening are mixed sand, silt, clay and rock. Testing in accordance with the
1991 Testing Manual indicates that these sediments meet the criteria estab-
lished in EPA's Ocean Dumping Regulations and Criteria for environmental
acceptability for ocean dumping. The new work dredged materials resulting
from the proposed ocean bar deepening, those beneath the maintenance materials
and those containing rock, were not chemically and biologically tested.
However, with regard to contaminants, the new work materials are believed to
be similar to the maintenance materials tested or even less affected by
anthropogenic contaminants due to their deeper and more isolated locations and
rock grain-size characteristics.
h. Presence in the material of any constituents which might sig-
nificantly affect living marine resources of recreational or commercial value:
The materials proposed for ocean dumping are naturally occurring sedimentary
materials which are similar to the materials which occur in the disposal site.
Constituents which might adversely affect living marine resources are not
known to be present in these materials.
Part 227.19 Assessment of Impact
The proposed ocean disposal of dredged material is not expected to have
significant adverse impacts on recreational use, and values of ocean waters,
inshore waters, beaches, and shorelines. The proposed ocean dumping is not
expected to adversely affect recreational and commercial values of living
marine resources. The impacts of the ocean dumping to aesthetic resources of
the marine environment, including ocean waters, inshore waters, beaches, and
shorelines, will be minor and insignificant. The disposal of dredged material
will locally and temporarily increase water column turbidity. Disposal models
indicate that the dredged material will quickly settle to the bottom following
release from the dredge. The material to be ocean dumped does not contain
chemical constituents or pathogenic organisms that would be released in
A-21
volumes which may affect humans or marine resources of recreational or commer-
cial value either directly or through food chain interactions.
Subpart E Impact of the Proposed Dumping on Other Uses of the Ocean
Part 227.20 Basis for Determination
An evaluation was made of the impact of the proposed dumping on long-term
impacts on other uses of the ocean in accordance with criteria established in
40 CFR Part 227 Subpart E. The other uses defined in this section are
specific uses of the ocean rather than overall aesthetic, recreational, and
economic values discussed in Subpart D.
Part 227.21 Uses Considered
The affects of the proposed ocean dumping on the following uses of the
disposal site and any areas which might reasonably be affected were evaluated.
Use
a. Commercial fishing in open ocean areas
b. Commercial fishing in coastal areas
c. Commercial fishing in estuarine areas
d. Recreational fishing in open ocean areas
e. Recreational fishing in coastal areas
f. Recreational fishing in estuarine areas
g. Recreational use of shoreline and beaches
h. Commercial navigation
i. Recreational navigation
J. Actual or anticipated exploitation of living
marine resources
k. Actual or anticipated exploitation of non-living
marine resources
1. Scientific research and study
Expected Impact
None
None
None
None
None
None
None
None
None
None
None
None
Notes:
* As indicated previously, mounding of material dumped within the Wilmington
ODMDS occurs. However, management of the site prevents mounding from becoming
a hazard to commercial navigation.
Part 227.22 Assessment of Impact
The proposed ocean dumping of dredged material is not expected to have
significant adverse impacts on other uses of the ocean, considering both tem-
porary and long-term effects.
f
A-22
LITERATURE CITED
Long, E.R. and Morgan, L.G. 1990. The Potential for Biological Effects of
Sediment-Sorbed Contaminants in the National Status and Trends Program. NOAA
Technical Memorandum NOS OMA 52.
McDonald. 1992. Draft Sediment Quality Guidelines for the State of Florida,
Florida Department of Environmental Regulation. Cited From: Evaluation of
the Region 4 Coastal Sediment Quality Inventory, Science Applications
International Corporation, 3 December 1992.
NOAA. 1989. A Summary of Data on Tissue Contamination from the First Three
Years (1986-1988) of the Mussel Watch Project. NOAA Technical Memorandum NOS
OMA 49. August 1989.
NOAA. 1991. Second summary on Chemical Concentration in Sediments from the
National Status and Trends Proaram. NOAA Technical Memorandum NOS OMA 59.
1991.
U. S. Army Corps of Engineers, Wilmington District. 1989a. Wilmington Harbor
Baldhead Island, Wilmington N.C. Reconnaissance Report, Section 111, PL 90-
483, January 1989.
U. S. Army Corps of Engineers, Wilmington District. 1989b. Final
Environmental Impact Statement, Long-Term Maintenance of Wilmington Harbor
Wilmington Harbor - Baldhead Island, Wilmington N.C. Reconnaissance Report,
Section 111, PL 90-483, January 1989.
Word, J. 1993, Senior Scientist, Staff Research Scientist, Marine Sciences
Laboratory, Battelle, Pacific Northwest Laboratories, Sequim, Washington.
Personal communication regarding metal enhancement factors.
A-23

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LOCATION DF OOMOS
THE FOLLOWING LOCATIONS ARE THE CORNERS OF THE EPA APPROVED
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ZONE TO BE USED FOR THIS JOB LI ES COMPLETELY WITHIN THE COALS
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Figure
ATTACHMENT B

PERTINENT CORRESPONDENCE
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING
WILMINGTON, NORTH CAROLINA
June 1993
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER To September 25, 1992
Dear Sir or Madam:
We are conducting studies for the preparation of an Environmental
Assessment (EA) or Environmental Impact Statement (EIS) for dredging of
the Wilmington Harbor Ocean Bar Channel to correct a construction depth
deficiency. We are now requesting comments from agencies, interest groups,
and the public to identify significant resources, issues of concern, and
recommendations for studies considered necessary. Comments received as a
result of this scoping letter will be considered as we conduct our studies
and identify potential impacts on environmental quality. These items will
be addressed, as appropriate, in the EA or EIS.
The Wilmington Harbor Ocean Bar Channel (also called Baldhead Shoal
Channel) is located at the mouth of the Cape Fear River and extends seaward
into the Atlantic Ocean (figure 1). This channel has been federally main-
tained for over 100 years. Authorized channel dimensions include a 500-foot
width, a 40-foot depth at mean low water (m.l.w), and 2 feet of allowable
overdepth. Construction of the channel to these authorized dimensions
was completed in 1973, except that the authorized depth was not uniformly
achieved due to rock obstructions and survey inaccuracies. In 1990, it
was determined that the actual controlling depth is approximately 38 feet.
due to the presence of several areas of rock in the channel. This depth
is inadequate to allow full utilization of the interior channels of the
Wilmington Harbor project, and larger vessels using the project must be
light loaded or wait for high tide to overcome this depth constraint
in the ocean bar channel. The North Carolina State Ports Authority has
requested that the authorized 40-foot depth be provided.
A plan is proposed to achieve the authorized 40-foot project depth,
plus an additional 4 feet of required overdepth, to accumulate shoaled
sediments between maintenance dredging events, and an additional 2 feet
of allowable overdepth for dredging inconsistencies. Such depths have
previously been considered achievable only by drilling and blasting the
rock along the channel bottom. However, during the spring of 1992, we
were able to remove rock using a rock cutterhead on a hydraulic pipeline-
dredge, so it is now considered feasible and practical to dredge to
this depth without blasting. Dredged material would be transported to a
disposal site by pipeline, hopper dredge, or dump scow. The plan would
also include extending the full channel depth seaward to approximately
station 350+00 (35,000 feet seaward of the intersection of Baldhead Shoal
Channel and Smith Island Channel). This point is about 11,000 feet beyond
the previously constructed and maintained channel, which ends at station
240+00. The channel would have side slopes of 1 vertical: 5 horizontal.
-2-
The estimated amount of dredged material to be removed is approximately
4 million cubic yards. The seaward channel extension and the increased
side slopes would result in the disturbance of approximately 170 acres of
ocean bottom, in addition to the 310 acres of channel bottom and side
slopes which are currently affected by maintenance dredging approximately
every 12 months. Disposal of dredged material could be at the Wilmington
Ocean Dredged Material Disposal Site, but other alternatives will also be
.considered. If suitable types and amounts of material could be obtained,
disposal alternatives could include (1) deposit of sand on the beach at
Bald Head Island and/or (2) construction of an offshore rock reef for fish
habitat. Plan modifications and disposal alternatives will be addressed,
as appropriate, during preparation of.the EA or EIS.
Environmental resource concerns relative to channel deepening and
seaward extension include the potential direct impacts of dredging and the
placement of.dredged material. Resources that will be addressed include
endangered and/or threatened species; marine and estuarine habitat; marine
and estuarine life; cultural resources, including important historic ship-
wrecks; and water quality. In addition, the indirect effect of channel
alteration on salinity changes within the Cape Fear River estuary and
coastal shoreline erosion at nearby ocean beaches will be addressed. The
beneficial use of dredged material for beach nourishment or fishery reef
construction will also be examined.
There is some concern that rock in the channel may prove to be too
hard for totally successful removal under the proposed plan. In this event,
limited drilling and blasting of any remaining rock could be required. As
advance preparation for such a situation and in order to assess and document
potential environmental effects, we would like to begin accumulating data,
comments, and suggestions concerning potential impacts of underwater
blasting and descriptions of measures for minimizing such impacts.
We request that you provide written comments on any of these matters
within 30 days from the date of this letter. If we have not received your
comments by then, we will assume that you have none. Comments should be
addressed to th'e District Engineer, (Attention: Mr. John Meshaw), U.S. Army
Corps of Engineers, Wilmington District, Post Office Box 1890, Wilmington,
North Carolina 28402-1890. If you have any questions, please contact
Mr. Meshaw, Environmental Resources Branch, at telephone [phone].
Sincerely,
Walter S. Tulloch
Colonel, Corps of Engineers
District Engineer
Enclosure
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WILMINGTON HARBOR. NORTH CAROLINA
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a' FIGURE 1
COMMENTS ON THE SCOPING LETTER RECEIVED FROM THE FOLLOWING:
Atlantic Coast Conservation Association
Bald Head Island Management, Inc.
Brunswick County Manager
City of Southport
National Marine Fisheries Service, Southeast Regional Office
New Hanover County Commissioners
North Carolina Department of Cultural Resources
• North Carolina Department of Natural Resources and Community Development
North Carolina Department of Transportation; Thomas J. Harrelson, Secretary
North Carolina Division of Environmental Management, Water Quality Section
North Carolina Division of Health Services
North Carolina Division of Coastal Management
North Carolina Ports Advisory Council
North Carolina State Clearinghouse
North Carolina Wildlife Resources Commission
Petroleum Fuel and Terminal Company
Propellor Club of the United States
Town of Carolina Beach
Village of Bald Head Island
Wilmington City Manager
Wilmington Industrial Development., Inc.
Wilmington Shipping Company
w
ATTACHMENT C
RECOMMENDATIONS OF THE O.S. FISH & WILDLIFE SERVICE
(PENDING COMPLETION OF THE DRAFT FISH & WILDLIFE COORDINATION ACT REPORT)
WILMINGTON HARBOR OCEAN BAR
CHANNEL DEEPENING

WILMINGTON, NORTH CAROLINA
June 1993
REC0MMMATIONS
FROM THE DRAFT FIBH & WILDLIFE COORDINATION ACT REPORT
The Service believes the following recommendations are
necessary and should be incorporated into project plans to
minimize the expected adverse impacts to fish and wildlife
resources.
1. The channel deepening contract should state clearly that
blasting should only be used as a.last resort after,it is shown
and documented that the rock cannot be removed with a
cutterhead dredge. The corps has stated that they cannot
require the contractor to complete the deepening project
without the use of blasting, even if blasting is not absolutely
necessary; however, the Corps' experimental rock removal has
demonstrated that the rock can probably be removed through
dredging. Therefore, to minimize unnecessary adverse impacts
to public trust resources, the Service prefers and recommends
that the project be done by dredging; however, we would
consider the use of minimal amounts of blasting if removal of
material with a rock cutterhead dredge is demonstrated not to
w
be physically possible. in the latter case, specific
additional mitigation measures would be necessary as addressed
in recommendations 2, 4, 5, 6, 7, 8, and 9.
2. If blasting is necessary, measures should be implemented to
minimize the lethal range of the blasts. Those measures should
include: drilling holes for the blasts; stemming the blasts;
using as low velocity explosives as is possible without
diminishing effectiveness; using instantaneous delays between
rows of blasts; and keeping the number of blasts per day and
the total number of blasts to a minimum. The Corps" draft
description of project plans stated that these measures will be
included in the contract, and we support efforts in this
regard.
3. Careful. time-of-year planning and impact preventative
measures are necessary for deepening activities so .as to avoid
or minimize impacts to sea turtles, migratory whales, West
Indian manatees, shortnose sturgeon and other anadromous
species, and estuarine dependent larvae.. Dredging and blasting
time frames should be developed in coordination with the
C

Service, the North Carolina Division of Marine Fisheries and
the National Marine Fisheries Service and will be specified in
the final report. The best time for blasting with regard to
estuarine dependent larvae and anadromous species may be the
period November 1 through December 15. The National Marine
Fisheries Service should be contacted regarding the best time
to conduct activities in order to avoid impacts to sea turtles,
marine mammals, and shortnose sturgeon. In order to avoid
impacts to the West Indian manatee, blasting activities should
be avoided between May through October.
4. The Corps should determine the expected lethal radius out
from the detonation site for- all groups of organisms, of
concern, and this information should be used to ensure that
blasting is avoided when large schools of fish are within the
lethal range of the blast site or when endangered or threatened
species are within the lethal range of the blast site. The
lethal range will likely vary based on the type of explosive
used and the measures implemented and will vary for different
species. The Corps should consider requiring the contractor to
use low velocity explosives because pressure increases are note
as rapid as they are when high velocity explosives are used,
and fish are more likely-to survive explosions.
5. If blasting occurs between May through October, surveys
should be made by at least two Service-approved and qualified
observers from aircraft or watercraft, immediately prior to
blasting, to ensure that no West Indian manatees are within the.
lethal range of the detonation. If a manatee is present within
the lethal range, blasting should be postponed until the animal
moves by its own will out of the impact zone. Similar
monitoring will probably be necessary for sea turtles, whales
and dolphins. However, the National Marine Fisheries Service
has jurisdiction over these species and the shortnose sturgeon,
and that agency should be contacted regarding protection of
these species.
6. Immediately prior to blasting, the impact zone should be
surveyed by qualified observers aboard a boat equipped with
fish finder echolocators or transducers. If large schools of
fish are located within. the lethal range of the blast site,
blasting activities should be avoided until the fish move out
of the lethal range.
7. The Corps should analyze the possibility of using sound as a
fish deterrence in order to disperse fish away from the
blasting zone, should blasting be necessary. This method
developed by Sonalysts, Incorporated, has been successful in
deterring alewives away from blasts during blasting activities
related to tunnel construction in Boston Harbor.
8. A comprehensive post-blasting monitoring plan should be
developed and implemented so that the species and number of
organisms killed by the blasts can be estimated. The-
monitoring plan should be developed in coordination with the
Service, the North Carolina Division of Marine Fisheries, and
the National Marine Fisheries Service and should involve
surveying the blasting impact area by boat and counting and.
identifying dead or wounded organisms which float to the
surface. Although all dead organisms may not float to the

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surface immediately, this method should give an indication of
the extent of the impacts to finfish and other organisms.
Other monitoring methods may also be necessary.
9. Although it has been determined that rock dredged from the
s
channel will likely be too. small to be high value artificial
reef material, rock removed by blasting may be of adequate size
to provide suitable reef habitat. Any material of appropriate
size should be tested to ensure it is free of contaminants and
if acceptable quality, should be used as artificial reef
material. Such an effort should be closely coordinated with
the National Marine Fisheries Service and the North Carolina
Division of Marine Fisheries. The Corps should ensure that all
rock rubble created through blasting is removed from the ocean
floor so that it does not destroy trawling nets.
14. To protect nearby beach habitats, limit the amount of sand
removed from the littoral system by using suitable material
dredged from the channel for beach nourishment of eroding
adjacent beaches, rather than placing high quality sand'
offshore at the ocean Dredged Material Disposal Site. The
z Corps should determine the sediment budget of the area and
determine how deepening the channel will affect the sediment
V -
budget.