129-16 Minor Mod 2020 Dare County Inlet Dredging

Permit Class
MODIFIOATION/MINOR
Permit Number
129-16
.STATE OF NORTH CAROLINA
Department of Environmental Quality
and
Coastal Resources Commission
Jkrmit
for
X Major Development in an Area of Errvirorrmental Concern
pursuant to NCGS 113A-118
X Excavation and/or tilling pursuant to NCGS 113-229
Issued to Dare County, 954 Marshall C. Collins Drive, Manteo NC 27954
Authorizing development in Hyde/Dare . County at Pamlico Sound and Hatteras Inlet complex
aa'. to the NE tip of Ocracoke _I land, as requested in the permittee's letter dated 3/14/20.
This permit, issued on April 3, 2020 , is subject to compliance with the application (where consistent
with the permit), all applicable regulations, special conditions and notes set forth below. Any violation of these terms may
civil action: or
1) Unless specifically altered herein, this Minor Modification authorizes the one-time dredging event of
the authorized channel via cutterhead pipeline dredge, all as expressly and specifically set forth in the
attached letter of request.
2) In order to protect threatened and endangered species and to minimize adverse impacts to intertidal
and beach resources, no excavation activities authorized under this Mi on shall occur
anytime after May 15, 2020 without prior approval from N.C. Division sal Management, in
consultation with the appropriate resource agencies. a 10
APR 2
OCtJI'MHo C11V
(See attached sheet for Additional Conditions)
This permit action may be appealed by the permittee or
other qualified persons within twenty (20) days of the issuing
date.
This permit must be accessible on -site to Department
personnel when the project is inspected for compliance.
Any maintenance work or project modification not covered
hereunder requires further Division approval.
All work must cease when the permit expires on
December 31, 2024
In issuing this permit, the State of North Carolina agrees
that your project is consistent with the North Carolina Coastal
Management Program.
Signed by the authority of the Secretary of DEQ and the Chair
of the Coastal Resourcesot'gnmission.
of Coastal Management
This permit and its conditions are hereby accepted.
OC,
Signature of PeRnittee

Dare Cou�uty
'J
Permit No. 129-16
Page 2 of 3
ADDITIONAL CONDITIONS
I.
Excavation
3) All excavation activities' shall take place entirely within the areas indicated on Figure 1 in the letter of
request and within the previously authorized channel dimensions (200': channel width).
4) Excavation shall not exceed =l2' Mean Low Water:
5) In order to prevent leakage, dredge pipes shall be routinely inspected. If leakage is found and repairs
cannot be made immediately, pumping of material shall stop until such leaks'are fixed.
6) Any excavation work conducted by sidecast dredge under this Minor Modification shall be performed
on an outgoing/falling tide.
Spoil Disposal
7) All materials excavated.by pipeline dredge shall be confined above normal high water and landward of
regularly or irregularly flooded marsh behind adequate dikes or other retaining structures to prevent
spillover of solids into any marsh or surrounding waters.
8) Prior to the initiation of any excavation Iby pipeline dredge, daily bird surveys shall be performed within
the DOT upland disposal site, and any nests shall be marked' and avoided. during the entire course of
work. Work shall"be conducted so that dredged material' avoids all marked areas and does not overrun
any bird nests.
9) The disposal area effluent shall be contained by pipe, trough, or similar device to a point at or beyond
the normal low water level to prevent gully erosion and unnecessary siltation.
10) A water controlstructure shall'be installed at the intake end of the effluent pipe to assure compliance
with water quality standards.
i
11) The terminal end of the pipeline shall be positioned at or greater than 50 feet from any part of the dike
and a maximum distance from spillways to allow settlement of suspended sediments.
12) The spoil area shall be approved by the Division of Coastal Management prior to the beginning of any
dredge activities.
General
13) This Minor Modification shall be. attached to the original of Permit No. 129-16, which was issued on
12/20/16, as well as all subsequent modifications and renewals, and copies of all documents shall be
readily available on site when a Division representative inspects the project for compliance.
14) All conditions and stipulations of the active permit remain in force under this Minor Modification unless
specifically altered herein..
15) The permittee and/or his or her contractor shall schedule a pre -construction conference with a
representative of the Division prior to project initiation.

Dare Couaty Permit No. 129-16
y Page 3 of 3
ADDITIONAL CONDITIONS
NOTE: A permit renewal application processing fee of $100 was received by DCM for this project.
NOTE: This permit does not eliminate the need to obtain any additional state, federal or local permits,
approvals or authorizations that may be required.
NOTE: The.N.C. Division of Water Resources has authorized the proposed project under DWR Project
No. 13-1279 v3.
NOTE: The U.S. Army Corps of Engineers authorized the proposed project under COE Action Id. No.
SAW-2016-02140.

COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
_________________________________________________________________________________________________________
4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409 910-791-9494 PHONE [phone] FAX

4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409  PHONE: [phone]  FAX [phone]
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.

March 14, 2020

Heather Coats
Division of Coastal Management
North Carolina Department of Environmental Quality
127 Cardinal Drive Ext.
Wilmington, NC 28405-3845

Re: Minor Modification to the Hatteras Inlet Channel Maintenance Project (CAMA Major Permit #129-16)

Dear Ms. Coats:

As you are aware, the Division of Coastal Management (DCM) issued a CAMA Major Permit for the proposed
Hatteras Inlet Channel Maintenance Project on December 22, 2016. This permit was recently renewed on
January 22, 2020. As stated in the permit application, the purpose of the project is to maintain navigation from
sloop channel (AKA the Horseshoe) into the Hatteras Inlet gorge via a connector channel or what is known as the
South Ferry Channel. Maintaining navigation through this dynamic area is necessary for commercial and
recreational boats to enter the Atlantic Ocean through Hatteras Inlet. Without adequate accessibility into the
inlet, the local economy would have continued to be impacted. Since the issuance of the permit, Dare County
has sponsored a total of six (6) dredging events following the deep water within the permitted dredge corridor
to maintain navigability to the inlet gorge. A permit modification was issued on March 14, 2018 allowing for 1)
a one-time open water disposal of up to 500 cubic yards of material; and 2) to widen the permitted channel
width from 150’ to 200’.

Several months ago, you informed us that the North Carolina Department of Transportation (NCDOT) was in the
planning stages of performing dredging operations in proximity of Hatteras Inlet utilizing a pipeline cutterhead
dredge in the near future (see the red polygon in Figure 1). NCDOT has performed multiple dredging events
using this dredge within the confines of Hatteras Inlet over the past several decades. Since learning about the
NCDOT’s proposed dredging, Dare County and representatives of our firm have reached out directly to the
NCDOT to learn more about their plan and how their dredging activity may benefit Dare County’s objective in
improving the navigability to the inlet gorge. During a call on March 5, 2020 with you and representatives from
NCDOT, Dare County, DCM, and our firm, we discussed the concept of using the NCDOT cutterhead pipeline
dredge to excavate a channel in a location most suited to clear and maintain a path through the shoals in the
South Ferry Channel which would benefit the navigation needs of Dare County while also achieving the NCDOT’s
goal of piping approximately 60,000-80,000 cubic yards of material to an upland disposal site located on
Ocracoke Island (Figure 1). The NCDOT has granted permission for Dare County to utilize this upland disposal
site as stated in a letter dated March 13, 2020 (Attachment 1). Depending on the success of NCDOT’s dredge
operation and scheduling, Dare County may perform additional maintenance dredging using a United Stated
Army Corps of Engineers (USACE) special purpose or sidecast dredge Dare County’s intentions are to conduct
enough maintenance dredging of the channel to allow for dependable navigation through this area during the
upcoming fishing tournament season and into October, when Dare County could once again begin routine
maintenance of the South Ferry Channel under the existing permit. Because Dare County is currently permitted
to only use sidecast and special purpose dredges, DCM Staff stated that Dare County is required to modify their
existing permits to allow the proposed action.

4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409  PHONE: [phone]  FAX [phone]
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
This letter serves as Dare County’s formal request to allow for a one-time event to utilize a cutterhead pipeline
dredge to dredge a channel 200’ wide and to a depth of -12 ft. MLLW with disposal of dredge material at the
NCDOT upland disposal site on the north end of Ocracoke Island. The remainder of this letter is intended to
provide information required to make an informed decision on granting the requested permit modification.

Figure 1. Location of the proposed pipeline dredge channel, historical NCDOT dredge footprints, and the upland disposal area.

4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409  PHONE: [phone]  FAX [phone]
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.

Purpose for this Modification
The utilization of the NCDOT’s cutterhead pipeline dredge to excavate a channel within the “Proposed Pipeline
Dredge Channel”, as identified in Figure 1, and potentially supplemented by follow-up maintenance dredging
performed by the USACE’s sidecast dredge, is intended to maintain navigability through the summer months.
This proposed maintenance plan is believed to have the most potential to minimize the need for prospective
emergency dredging later into the summer months when biological resources may be more sensitive to
dredging related activities. Beyond the economic benefits to the local economy as a result of maintaining
dependable navigation in this area, the proposed action is intended to curtail safety concerns for mariners. In a
letter dated March 12, 2020, in response to current conditions the United States Coast Guard (USGS) stated that
“the reduced channel depth (in South Ferry Channel) limits offshore access by surf-capable response assets from
USCG Station Hatteras Inlet and potentially extends their search and response times by more than two hours”
(Attachment 2).

Construction Schedule
Based on feedback from NCDOT, they could be available to start dredging starting around the second week of
April. They anticipate needing approximately 3-4 weeks of dredge time to satisfy their needs. Depending on the
condition of the channel and scheduling, Dare County may request the USACE to conduct supplemental dredging
using the sidecast Dredge Merritt in parallel or shortly after the completion of NCDOT operations.

Sediment Characterization
The material excavated by the NCDOT cutterhead pipeline dredge will be pumped to the upland site located on
the northeastern tip of Ocracoke Island where it will be temporarily stockpiled and used for NCDOT projects.
The USACE collected a series of vibracores in 2003 in order to characterize the material from within the Hatteras
Inlet complex. A total of 12 vibracores were collected and analyzed during this effort of which 4 were located
within the first channel that was dredged under this permit in the spring of 2017. Analysis of these four
vibracores revealed that the material was primarily composed of light gray to olive gray, poorly graded fine to
medium sands with trace shells having less than 5% silt. This material is designated as an “SP” soil type under
the Unified Soil Classification System (USCS). The results of laboratory testing showed the mean grain size of
the samples analyzed ranged from 0.22 mm to 0.33 mm and the silt content, defined as % passing the #200
sieve, ranged from 0.0% to 1.3%. The vibracore logs show the depths to the channel bottom at the boring
locations ranged from -5.0 ft. to -15.9 ft. below Mean Low Water (MLW) and extended to depths ranging from -
13.2 ft. to -21.9 ft. below MLW. In addition to the information provided by this geotechnical analysis, NCDOT
staff have stated that the material dredged by the NCDOT pipleline dredge and placed in the upland facility in
the past has been clean sand.

Impacts Associated with the Use of a Cutterhead Pipeline Dredge
When sediment re-suspension occurs as a result of dredging activity, larger particles rapidly settle out; however,
the finer sediments may remain suspended for longer periods, or even indefinitely in turbulent water (Adriaanse
and Coosen, 1991). Suspended particles may interfere with the biological functions of some organisms such as
feeding, respiration, reproduction and potentially cause predator avoidance. High turbidity and silt loads can
have detrimental impacts to filter feeding organisms associated with nearshore benthic communities including
amphipods, isopods, decapods, polychaetes, mollusks and others. The conditions of diminished light penetration
can detrimentally affect the photosynthetic activity of phytoplankton, the primary producers of energy
production. Additionally, turbidity can affect the health of submerged aquatic vegetation (SAV). These impacts,
however, are often realized mainly through the use of sidecast or special purpose dredging activity. Unlike
sidecaster and special purpose dredges, pipeline cutterhead dredges generate comparatively lower amounts
of suspended sediment plumes which are confined to within a few meters of the drilling cutterhead at the

4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409  PHONE: [phone]  FAX [phone]
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
seafloor. A pipeline dre dge sucks dredged material through one end, the intake pipe, and then pushes it out the
discharge pipeline directly to the disposal site. They function by drilling below the surface of the substrate;
therefore, the sediment plumes created from the drilling cutterhead are generally highly localized (CSA et al.,
2009) compare to the impacts associated with sidecast or special purpose dredges. Additionally, the material is
hydraulically moved from the cutterhead /sediment interface directly into a pipeline, eliminating the hopper-
filling stage and associated overflow when hopper dredges are utilized. Because pipeline cutterhead dredges
create minimal sediment plumes compared to the other dredge types, turbidity-related impacts would be
minimized through the use of the pipeline dredge to conduct the majority of the dredge maintenance work for
this one-time event proposed to occur after March 31.

Operational differences between dredge types contribute to the differences in potential impacts to sea turtles.
Thus far, no incidental takes of sea turtles have been reported as a result of operations utilizing pipeline
cutterhead dredges operating in southeastern coastal channels (Dickerson et al., 2004). The relatively slow
dredging motion of pipeline dredges also presents minimal risk for sea turtle takes as a result of collisions.

Dredging within the Dredge Moratorium
The County’s goal is to maintain safe navigation through Hatteras Inlet throughout the year. In order to do so,
since 2017, they have implemented two dredge events each year utilizing a sidecast or special purpose dredge.
These events have strategically been scheduled just prior to and just following the dredge moratorium in an
attempt to avoid the need to request relief for emergency dredging during the warmer summer months. Dare
County was well positioned to conduct a dredge maintenance event in October 2019 when the USACE and
Division of Water Resources (DWR) announced that the two agencies had allowed the MOU that allowed for the
USACE to conduct the dredging for this project to expire. By no fault of Dare County, the dredge event was
postponed until early January. By that time, shoaling in the channel had reached a critical level. Despite
dredging attempts by the Dredge Merritt between January 27 and February 12, the channel remained
significantly shoaled. Based on the most recent efforts by the USACE Dredge Merritt, it is unlikely that the
remaining budgeted sidecast dredging available would effectively clear the shoaling and render the channel
navigable.

Previously Obtained Authorizations
The NCDOT received a Department of Army Permit (Action ID #SAWCO-N-028-000318), a CAMA Major Permit
(#224-87), and a Special Use Permit issued by the National Park Service (NPS) (#5700-028) allowing for the
operation of a cutterhead pipeline dredge within a portion of Hatteras Inlet with the disposal of material at the
upland disposal facility located on the northeast corner of Ocracoke Island. They have obtained permit
modifications in the past allowing for similar dredge activities to occur in various areas within the inlet complex
(see Figure 1 above).

Dare County received a Department of Army Permit (Action ID #SAW-2011-02140) on March 1, 2017 and a
CAMA Major Permit (#129-16) on December 20, 2016 allowing for maintenance dredging to -12’ MLLW within a
defined corridor utilizing the USACE’s sidecast and special purpose dredge plants. Figure 1 shows the extent of
the permitted dredge corridor in which all of the six dredge maintenance events conducted by Dare County and
most of the pipeline dredging conducted by the NC DOT has occurred. Permit modifications to the Department
of Army and CAMA Major permits were made on August 29, 2017 and March 14, 2018, respectively allowing for
a wider (200’) channel.

Collectively, the permits held by both entities (NCDOT and Dare County) allow for the proposed activities
included in this permit modification request. With that context, Dare County respectfully requests that you

4038 MASONBORO LOOP ROAD, WILMINGTON, NC 28409  PHONE: [phone]  FAX [phone]
COASTAL PLANNING & ENGINEERING OF NORTH CAROLINA, INC.
expeditiously consider processing this permit modification such that the required planning and coordination
may be carried out in time to minimize any requests to dredge into the summertime months.

If you have any questions, please feel free to contact me directly at 910-352-1555.

Sincerely,

Brad Rosov
Senior Marine Biologist
Coastal Protection Engineering of North Carolina, LLC

Office: 910-791-9494
Mobile: [phone]
[e-mail]

CC:
Brent Johnson, Dare County
Ken Willson, CPE-NC

Attachment 1: Letter from NCDOT

Attachment 2: Letter from US Coast Guard