20191338 Ver 1_NMFS Concurrence SERO-2019-00475 Isabel Holmes Bridge Cable Installation_FINAL_20191004

OF
UNITED STATES DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
NATIONAL MARINE FISHERIES SERVICE
Southeast Regional Office
Qf&*St.
263 13th Avenue South
Petersburg, Florida 33701-5505
https://www.fisheries.noaa.gov/region/southeast
09/18/2019 F/SER31: SBC
SERO-2019-00475
Brad Shaver
Wilmington Regulatory Field Office
U.S. Army Corps of Engineers
69 Darlington Ave.
Wilmington, North Carolina 28403
Philip S. Harris III, P.E., CPM, Unit Head
Environmental Analysis Unit
North Carolina Department of Transportation
1598 Mail Service Center
Raleigh, North Carolina 27699-1598
Dear Sirs:
This letter responds to your request for consultation with us, the National Marine Fisheries
Service (NMFS), pursuant to Section 7 of the Endangered Species Act (ESA) for the following
action.
Applicant(s)
ECO Number
Project Type(s)
North Carolina
SERO-2019-00475
Installation of a submarine cable in the Cape Fear
Department of
River
Transportation
Consultation History
We received your letter requesting consultation on April 29, 2019. We requested additional
information on June 5, 2019. We received a final response on August 29, 2019, and initiated
consultation that day.
Project Location
Address
Latitude/Longitude
Water body
Public Road (US 74/NC 133) including
34.2519670N, 77.950739°W
Cape Fear
bridge over the Northeast Cape Fear River
(North American Datum 1983)
River
in New Hanover County, North Carolina

Image of the project location and surrounding area ((D2015 Google)
Existing Site Conditions
The project area is located in the Northeast Cape Fear River, approximately 26.8 river miles
(rmi) from the Atlantic Ocean in Atlantic sturgeon critical habitat. Existing structures include a
submarine cable and bascule (drawbridge) bridge with an over -water bridge length of
approximately 840 feet (ft) and an over -water area of approximately 1.3 acres (ac) (54,000
square feet [ft2]). The width of the Cape Fear River at the project area is approximately 850 ft
wide. Water depths are approximately 36-41 ft deep per diver's report. The substrate at the
Cape Fear River in the vicinity of the proposed crossing is sand and silt. No seagrasses or other
marine vegetation are located in the project area.
Project Description
The U.S. Army Corps of Engineers requests authorization to permit in -water work preservation
activities for the North Carolina Department of Transportation (NCDOT) on the Isabel Holmes
Bascule Bridge on US 74/NC 133 over the Northeast Cape Fear River. The proposed action will
include the replacement of a new buried submarine cable that conveys power to the drawbridge
mechanism. Construction will include the installation of 4 composite armored cables encased in
high -density polyethylene (HDPE) pipe buried below the mudline. The existing cable is in an
adjacent location and is proposed to be left in place. The total linear footage (lin ft) of the new
cable based on the proposed alignment is approximately 300 ft.
The cable will be installed via trench, which will require excavation to an average depth of 3 ft
below the mudline, depending on the location. Only 216 ft of the 300-ft proposed alignment will
require trench excavation. The contractor will use a hydraulic suction pump to dig the trench,
which would be completed by divers using a handheld vacuum device powered by a hydraulic
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pump (mounted on a barge) to remove sediment, then captured in geotextile dewatering bags.
The proposed method of installation beneath the fenders is to use jetting; however, if site
conditions allow, the contractor will attempt the suction method beneath the fenders. The
material removed from the trench will be disposed of off -site in an approved manner and in
accordance with all applicable federal, state, and/or local laws and regulations. Any material
designated as hazardous waste shall be disposed of at an approved hazardous waste site. Sand
and silt displaced from any required jetting will not be captured, though these areas would be
small. The trench will be backfilled with approximately 72 cubic yards (yd3) of a mixture of
crushed stone and sand, crusher dust, or pea gravel.
The applicant anticipates that the duration of in -water work will take several weeks (dependent
upon weather and other factors) and has agreed to conduct work during daylight hours only.
Construction Conditions
The applicant has agreed to adhere to NMFS's Sea Turtle and Smalltooth Sawfish Construction
Conditions and will apply them to Atlantic sturgeon.' In addition, the applicant will abide by a
seasonal restriction for Atlantic sturgeon and restrict cable installation to between December 1
and January 31. A primary nursery area in -water work moratorium of February 1 to September
30 is also in effect for this project. Given the depth and strong current at the project site,
NCDOT will not utilize a turbidity curtain.
Effects Determination(s) for Species the Action Agency or NMFS Believes May Be Affected
by the Proposed Action
ESA Listing
Action Agency
NMFS Effect
Species
Status
Effect
Determination
Determination
Fish
Shortnose sturgeon
E
None made
NLAA
Atlantic sturgeon (Carolina DPS)
E
None made
NLAA
Critical Habitat
The project is located in Atlantic sturgeon critical habitat Carolina Unit 4. The physical and
biological features (PBFs) of the critical habitat are described in the table below. We believe
only the salinity gradient and soft substrate (PBF 2), unobstructed water of appropriate depth
(PBF 3), and water quality (PBF 4) may be affected by the proposed action. PBF 1 is not present
at the project site.
1 NMFS. 2006. Sea Turtle and Smalltooth Sawfish Construction Conditions revised March 23, 2006. National
Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Regional Office, Protected
Resources Division, Saint Petersburg, Florida. https://www.fisheries.noaa.gov/webdam/download/92937961
2 E = endangered; T = threatened; NLAA = may affect, not likely to adversely affect; NE = no effect; NP = not
present

PBF
Identification
Features
Purpose/Function of PBF
Hard
Hard bottom substrate (e.g.,
Necessary for the settlement of fertilized
Substrate
rock, cobble, gravel, limestone,
boulder, etc.) in low salinity
eggs and refuge, growth, and development
(PBF 1)
waters (i.e., 0.0-0.5 ppt range)
of early life stages
Aquatic habitat inclusive of
Salinity
waters with a gradual
Gradient and
downstream gradient of 0.5 up to
Necessary for juvenile foraging and
Soft Substrate
as high as 30 parts per thousand
physiological development
(PBF 2)
and soft substrate (e.g., sand,
mud) between the river mouth
and spawning sites
Necessary to support:
• Unimpeded movement of adults to and
from spawning sites;
• Seasonal and physiologically
Water of appropriate depth and
dependent movement of juvenile
Unobstructed
absent of physical barriers to
Atlantic sturgeon to appropriate
Water of
passage (e.g., locks, dams,
salinity zones within the river estuary;
Appropriate
thermal plumes, turbidity, sound,
and
• Staging, resting, or holding of
Depth (PBF
reservoirs, gear, etc.) between
subadults or spawning condition
3)
the river mouth and spawning
adults. Water depths in main river
sites
channels must also be deep enough (at
least 1.2 m) to ensure continuous flow
in the main channel at all times when
any sturgeon life stage would be in the
river
Necessary to support:
• Spawning;
• Annual and inter -annual adult,
Water quality conditions,
subadult, larval, and juvenile survival;
Water Quality
especially in the bottom meter of
and
(PBF 4)
the water column, with
. Larval, juvenile, and subadult growth,
appropriate temperature and
development, and recruitment.
oxygen values
Appropriate temperature and oxygen
values will vary interdependently, and
depending on salinity in a particular
habitat.
Analysis of Potential Routes of Effects to Species
Sturgeon may be injured due to interaction with the barge -mounted hydraulic suction pump and
jetting activities during cable installation. However, we believe this effect is discountable. The
suction pumping will be completed by hand via divers and therefore the likelihood of a sturgeon
interacting with the suction pump is greatly reduced. By restricting in -water work to December

I — February 1, which is outside of the predicted spring and fall spawning period for Atlantic
sturgeon, the likelihood of sturgeon presence coinciding with in -water construction is also
greatly reduced. If sturgeon are present, they are likely to move away and will be able to access
other portions of the river outside of the project area to avoid mechanical equipment during the
excavation and installation of the cable. The applicant's implementation of NMFS's Sea Turtle
and Smalltooth Sawfish Construction Conditions will further reduce the risk by requiring all
construction workers watch for sturgeon. Operation of any mechanical construction equipment
will cease immediately if a sturgeon is seen within a 50-ft radius of the equipment. Activities
will not resume until the protected species has departed the project area of its own volition.
The project area contains habitat that may be used by Atlantic and shortnose sturgeon for
spawning, foraging, and refuge. Sturgeon may be temporarily affected by their inability to
access the project site due to their avoidance of construction activities and physical exclusion
from the project area due to trench dredging and cable installation, however we believe this
effect will be insignificant. By restricting in -water work to December 1 — January 31 which is
outside of the predicted spring and fall spawning period for Atlantic sturgeon, the likelihood of
sturgeon presence coinciding with in -water construction (e.g., trench excavation and cable
installation) is greatly reduced. For any sturgeon that are present during construction, river
access at the project site will not be completely blocked at any time during the proposed cable
installation. The proposed project will not span the entire width of the river, and therefore will
allow sturgeon upriver/downriver access at all times during construction. Upon project
completion, pre -project habitat characteristics will be restored, the suction and jetting pump and
barge will be removed, and Atlantic sturgeon will have access to the habitat again. In -water
work will also only occur during daytime hours, leaving noise -free periods during the night when
sturgeon can transit through the area to move upstream or downstream of the project location.
Analysis of Potential Routes of Effect to Critical Habitat
Trench excavation may affect aquatic habitat with a gradual salinity gradient and soft substrate
(PBF 2) by removing soft sediments at the project site used by juvenile Atlantic sturgeon for
foraging and physiological development. We believe this effect to PBF 2 will be insignificant.
Although the sediment used to backfill the excavated material will consist of a new mixture of
hard and soft sediments, the amount of soft sediment removed would be at such a small amount
and limited compared to the area of sand and silt available adjacent to the project area and in the
Cape Fear River. Excavation and construction will have no effect on the salinity gradient in the
project area.
The unobstructed water of appropriate depth (PBF 3) may be affected by the proposed action.
For the life stages potentially using the action area, PBF 3 refers to water that is free from
obstruction such that: spawning adults can make unencumbered movements to the spawning
grounds; adults can access staging, resting, and holding habitats; and juveniles can make
seasonal and physiologically -dependent movements to appropriate salinity zones within the
river. It also refers to the requirement that the main channel be deep enough to ensure that there
is continuous flow when adults or juveniles are there. The project will not alter the depth of the
main channel. Cape Fear River waters will be partially and temporarily obstructed by the
presence of construction equipment and excavation, but these effects will be insignificant due to
the temporary nature of the project. By restricting in -water work to December 1 — February 1,
which is outside of the predicted spring and fall spawning period for Atlantic sturgeon, the
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likelihood of sturgeon presence coinciding with in -water construction (e.g., suction pumping or
jetting, and cable installation) is greatly reduced. If sturgeon are present, the installation of the
cable and dredging activities will only affect a small portion of the river at a time.
Water quality (PBF 4) supporting important life functions, such as growth and reproduction, of
various life stages of Atlantic sturgeon may be affected by increases in temperature and
decreases in Dissolved Oxygen (DO) caused by increased turbidity from cable installation,
jetting, and suction pumping to create the trench. Suspended sediments that create turbidity
absorb more heat than water molecules, potentially raising the water temperature, and decreasing
the ability for oxygen to remain dissolved in the water column. Suspended sediments may also
decrease DO by reducing light for photosynthesis by aquatic plants or increasing oxygen demand
due to decomposition if the suspended sediments are high in organic materials. We anticipate
very minor and temporary increases in temperature and decreases in DO that will have an
insignificant effect on PBF 4 due to (1) the temporary duration of the project and during daylight
hours only, (2) the layer of sediment removed during excavation (to a depth of 3 — 4.5 ft) and
backfilled is expected to generate localized turbidity limited to the locations of the equipment
and the backfill is expected to remain in the bottom, and (3) the rapid removal and redeposition
of sediments on the outgoing tide.
Conclusion
Because all potential project effects to listed species and critical habitat were found to be
discountable, insignificant, or beneficial, we conclude that the proposed action is not likely to
adversely affect listed species and critical habitat under NMFS's purview. This concludes your
consultation responsibilities under the ESA for species under NMFS's purview. Consultation
must be reinitiated if a take occurs or new information reveals effects of the action not previously
considered, or if the identified action is subsequently modified in a manner that causes an effect
to the listed species or critical habitat in a manner or to an extent not previously considered, or if
a new species is listed or critical habitat designated that may be affected by the identified action.
NMFS's findings on the project's potential effects are based on the project description in this
response. Any changes to the proposed action may negate the findings of this consultation and
may require reinitiation of consultation with NMFS.
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We look forward to further cooperation with you on other projects to ensure the conservation of
our threatened and endangered marine species and designated critical habitat. If you have any
questions on this consultation, please contact Shelby Creager, Consultation Biologist, at (727)
209-5951, or by email at [e-mail].
File: 1514-22.f.1/1514-22.1.1
Sincerely,
BERNHART.DAWD.M.10
66125889
2019.09.18 12:38:55-04'00'
David Bernhart
Assistant Regional Administrator
for Protected Resources
7