20011868 Ver 3_More Info Received_20231108

Town of Sunset Beach Navigation Project
Maintenance Dredging of Mary's and Turtle Creek
CAMA Major Permit Modification Request
Project Narrative
November 3, 2023
(Supersedes Narrative Revisions dated July 14, 2023, June 28, 2023, and July 28,2022)
INTRODUCTION
The Town of Sunset Beach (Town) requests authorization to modify CAMA Permit No. 132-18, U.S. Army
Corps of Engineers Permit No. SAW-2002-00247, and State Water Quality Certification No. 2001-1868v2,
which were originally issued to allow shallow navigational dredging in Mary's and Turtle Creek. This
project falls within a larger scope by the Town to maintain navigation access to the residential channels
and canals along the eastern portion of Sunset Beach. Mary's and Turtle Creek connect to the AIWW near
the entrance to North Jinks Creek and the Sunset Beach causeway. These creeks lie adjacent to public and
private properties within the Town of Sunset Beach (Brunswick County) and provide navigation access to
residents and visitors of the area. Figure 1 shows the project area in relation to Brunswick County.
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Figure 1. Project Vicinity Map
This modification requests the authorization to update the dredge limits for Mary's and Turtle Creek. The
modification is based on agency comments from a meeting on October 5, 2023 to address the remaining
shellfish resource at the mouth of Turtle Creek (Station 3+50 — 5+00). Additionally, this modification
involves establishing a new primary offloading area at the western end of Mary's Creek specifically
designated for the dredged material from this project. Offloading at Mary's Creek would be conducted in
similar method as Cobia St., with temporary gabion baskets to support the existing vinyl sheet pile wall
from landside loading.
PROJECT PURPOSE AND NEED
To satisfy NCDCM permit condition #9, shellfish relocation was conducted in both Mary's and Turtle Creek
prior to the start of dredging for the 2023/2024 dredge season. During the relocation efforts, there was
an area of extensive shellfish resource identified within the previously permitted dredge limits, which was

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
unable to be relocated. A subsequent meeting was held on October 5, 2023, to discuss design
modifications to minimize impact to the remaining shellfish resource and to ensure a mutual
understanding of what are considered to be dredge limits and direct impact due to dredging. Based on
agency comments, dredge limits are considered to be direct removal of material by the dredge. Natural
sloughing, or equilibration, of the side slopes is not considered direct impact due to dredging; therefore,
can occur outside of the dredge limits. Based on this meeting, it was determined that the channel design
would need to be modified in this specific location in order to minimize impact to the remaining shellfish
resource. The remaining dredge limits for the revised channel design (outside of this area of concern) stay
within the previously permitted dredge limits.
Additionally, the Contractor has identified the Town owned park on the western side of Mary's Creek for
the offloading of dredge material. Use of this offloading area would expedite the construction process
during the 2023/2024 dredge season by significantly decreasing the distance to the offload site, which will
decrease downtime between digging and offloading. While the Contractor does not intend to utilize the
previously permitted Seaside Road Staging and Offloading Area or Cobia St. Offloading Area as the primary
offloading area for the upcoming dredge effort planned to start in October 2023, the Town reserves the
right to allow the Contractor to utilize either of these two areas if unforeseen circumstances lead to the
Mary's Creek offload area becoming unavailable for usage.
PROPOSED MODIFICATION
Dredge Limits Modification
The currently authorized dredge limits for these channels were based on the surveys performed in August
23-24, 2016. The original permitted template was a box cut and did not account for side slopes. The
template was updated to account for an assumed side slope of 3H:1V for both Mary's and Turtle Creek.
An updated survey was performed by Geodynamics between August 24 — 27, 2020, which shows the
existing ground within the dredging limits averaged between -0.5— -0.7 ft MLW. The dredge alignment
and channel design were modified from previously permitted, as noted in Table 1, due to the addition of
side slopes and address shellfish resource.
To address agency concerns of dredge impacts to the remaining shellfish resource at the mouth of Turtle
Creek (Station 3+50 — 5+00), the channel base width was reduced from 40 ft to 17 ft (23 ft reduction) to
minimize impact to this resource (see sheet C-101 of provided permit drawings dated 10-09-2023).
The modified dredge design reduced the channel base width in certain locations from the design shown
in the original permit drawings (dated October 2018), in an effort to minimize impact to marsh grass and
existing infrastructure such as docks with structural piles that are currently present during this dredge
event. A field investigation identifying key structures to avoid was performed by Moffatt & Nichol in July
2021. These locations were utilized in the redesign of the channel to ensure no adverse impact to
structural piles while maximizing material removal. Spartina alterniflora exists along the intertidal and
supratidal regions of Mary's and Turtle Creek. An updated marsh grass survey was performed in June of
2021 for Mary's and Turtle Creek, which is shown on Sheet C-101 of the permit drawings included in Tab
C. Future dredge events will re-evaluate the conditions of the marsh grass and infrastructure at the time
of construction and the channel design will be modified to minimize impact to these resources while
remaining within the previously permitted dredge limits.
2

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
Coastal marsh grass has encroached within or close to the originally anticipated dredge area of Mary's
and Turtle Creek. Therefore, to minimize potential impacts to the marsh grass, no excavation, including
the excavation of side slopes, will take place within 10 ft of any marsh grass at the time of construction.
This 10 ft buffer differs from the originally permitted 20 ft buffer due to the fact that the 20 ft buffer was
based off of a box cut during dredging; therefore, the 20 ft buffer needed to account for equilibration of
side slopes. Because the current proposed dredge template incorporates the dredging of side slopes, a 10
ft buffer has been determined to be sufficient. During construction, the dredge contractor shall be
prohibited from directly dredging material within this marsh grass buffer zone. These precautions will help
minimize the potential for environmental impacts on this project.
The modifications made have resulted in an overall increase in the volume of dredging (see Table 1) and
a decrease in dredge limits area (see Table 2) in Mary's and Turtle Creek. Table 2 provides a summary of
the difference between the previously permitted dredge limits area and the proposed dredge limits area
based on the design modifications, which resulted in a decrease of 0.1 acre. This decrease is attributed to
the reduction in dredge limits at the mouth of Turtle Creek in order to minimize impact to the remaining
shellfish resource. Table 3 summarizes the change in dredge limits within each creek, highlighting the
areas of decreased dredge limit at the mouth of Turtle Creek. The original permit did not consider side
slopes, but the new drawings now incorporate slopes. Dredging of the side slopes will be contained within
the previously permitted dredge limits, which results in no change to the dredge limits area. Again, all
dredging will be prohibited within 10 ft of existing marsh grass as the time of construction. For further
reference, please review the permit drawing in Tab C. The increase in volume from the previously
authorized amount is approximately 1,900 cy (previously permitted volume was 15,900 cy) as shown in
Table 1. This adjustment was made in part due to the lessons learned from the South Jinks Creek
Navigation project where the dredge area changed between the time of permitting and the time of
construction. The updated dredge limits and alignments are shown on Sheet C-101 of the permit drawings
included in Tab C.
Table 1—Dredge Channel Design
Existing
Proposed
Modified
Dredge
Side
Permitted
Est.
Channel
Avg.
Depth
Length
Channel
Limit
Slope
Volume
Maximum
Depth
(MLW-ft)
(ft)
Base
Width (ft)
(H:V)
(CY)
Volume
(MLW-ft)
Width (ft)
(CY)
-6 (-5+1)
Mary's
-0.7
-5 (-4+1)
1,075
8-60
25 — 60
3:1
8,100
8,100
Creek
-4 (-3+1)
-6 (-5+1)
Turtle
-0.5
-5 (-4+1)
1,100
14-40
17 — 40
3:1
7,800
9,723
Creek
-4 (-3+1)
TOTAL
2,175
Varies
Varies
3:1
15,900
17,823
*Volume Reported from Original Permit Application
3

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
Table 2 — Dredge Limits Area Summary
Previously
Proposed
Difference
Channel
Permitted
Modified
(Acres)
Area (Acres)
Area (Acres)
Mary's Creek
1.1
1.1
0.0
Turtle Creek
1.0
0.9
-0.1
Total
2.1
2.0
-0.1
Table 3 — Dredge Limit Change Summary
Dredge
Limit Change
Channel
Distance (ft)
Stations
Notes
Mary's Creek
0
0+00 —10+82
No Change in Dredge Limits
Turtle Creek
0 — (-23)
3+25 — 5+00
Reduction on East Side of Channel
for Remaining Shellfish Resource
Offloading Site Modification
During the 2022/2023 dredge window, the Contractor requested approval to use the Town owned
property on the western side of Mary's Creek as the primary offloading site for dredge material from
Mary's Creek and Turtle Creek as shown in Figure 2. The Contractor noted this site as being more efficient
due to the shorter transit time when compared to the currently permitted offloading site at Seaside Road.
Offloading at Mary's creek would be conducted in similar method as Cobia St. Temporary gabion baskets
are required to support the existing vinyl sheet pile wall from landside loading. The area targeted for
install of the gabion baskets and offloading of material is an area approximately 15 — 20 ft wide that is
void of marsh grass as shown in Figure 2 in order to minimize environmental impact.
Figure 2: Primary Offloading Site: Mary's Creek Marsh Grass
11

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
The design of the temporary gabion bulkhead is shown on Sheet S-501 of the permit drawings. The
Contractor will be required to install silt fence around the active offloading area and install temporary
timber matting for support of construction vehicles. Material offloaded from the barges will be required
to be placed directly into sealed dump trucks for transit to the previously permitted disposal area off Old
Georgetown Road. At no time will dewatering of material be allowed at this site. Sufficient safety signage
and traffic control measures will be required at the ingress/egress given this is a high traffic area for
residents and visitors. After construction is complete, the Contractor will be required to make any repairs
to damage caused by the Project work in order to return the offloading area to pre -project conditions.
In order to assess the potential impact to coastal marsh grass due offloading activities, the Town will
monitor the area post construction for 12 months via photo documentation. If loss of marsh grass is
recorded, the Town will implement marsh grass planting in order to mitigate the impact.
Cobia Street Alternate Offload Area
The previously permitted Cobia St. Offloading Area has been identified as an alternate offloading area in
the event that the Seaside and Mary's Creek sites become unusable. The Cobia offloading area is already
constructed and has obtained the necessary permits for work within the Bay Area, Feeder, and Finger
Canals. The proposed plan ensures that barges would only travel through North Jinks Creek when water
levels are such that the barges will not adversely affect the bottom habitat of the creek.
ADDITIONAL ENVIRONMENTAL CONCERNS
As part of the previously permitted components of this project, the Town evaluated potential impacts to
managed or endangered species that may occur as a result of the overall project. While these reports
were completed as part of the original permit submittals, the findings should be expected to apply to the
proposed project modifications. Tab E provides an Essential Fish Habitat (EFH) assessment, and Tab F
provides a Biological Assessment (BA) for the project. Generally, the referenced reports support the
findings that the project should not adversely impact threatened or managed species.
Additional precautions proposed for the maintenance project include following U.S. Fish and Wildlife
Service (USFWS) recommended guidelines for avoiding impacts to West Indian Manatee and
recommendations provided by the National Marine Fisheries Service (NMFS) to help protect sea turtles
and smalltooth sawfish. Tab G (Manatee Avoidance Guidelines) shows the manatee guidelines while Tab
H (NMFS Recommendations) includes the sea turtle and smalltooth sawfish precautions. Based on the
scoping meeting on July 1, 2022, the Town will coordinate with permitting and resource agencies to avoid
and minimize impacts to coastal marsh and other resources within the proposed modification footprint.
HISTORIC RESOURCES
The applicant has also contacted the State Historic Preservation Office (SHPO) as part of the original
permit submittals to inquire on any known historic resources in the area such as shipwrecks or
archeological artifacts. These inquiries did not identify any known resources with the potential to be
impacted by the project. Tab I (SHPO Resource Review) provides the written response from SHPO. It is
again reasonably expected that these findings may also be applied to the proposed project modification.
5

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
SUMMARY
The Town of Sunset Beach requests a permit modification to 1) modify the dredge limits to account for
the side slope and minimize infrastructure and environmental impacts to the remaining shellfish resource,
and 2) add a new primary offloading area at Mary's Creek for the dredge material from Mary's Creek and
Turtle Creek. These modifications will provide a viable plan for completing the dredging efforts with
minimal environmental impacts.
The project will help restore navigation access to the AIWW while maintaining a buffer zone between the
work area and any coastal marsh or wetland habitat. The work will also follow additional guidelines and
recommendations provided by USFWS and NMFS to further minimize the potential for environmental
impacts during construction. The project will adhere to environmental moratoria design to protect
juvenile fish and shellfish. Additionally, the project will follow construction guidelines designed to protect
manatees, sea turtles, and smalltooth sawfish.
ADDITIONAL ITEMS RELATED TO CAMA PERMIT APPLICATION PACKAGE
State Environmental Policy Act (SEPA) Compliance
§ 113A-12(6) states that the preparation of an environmental document shall not be required for projects
that require a Coastal Area Management Act major permit. Therefore, no SEPA document will be prepared
for the proposed project modification. Previous permits and the agency scoping meeting associated with
this project are provided for reference in Tab J.
Application Fee
A permit application processing fee will be provided separately.
Adjacent Riparian Property Owner Notifications
At the advice of NCDCM staff, adjacent riparian property owner notifications were mailed (certified mail,
return receipt requested) to the riparian properties immediately adjacent to Mary's and Turtle Creek. A
copy of the letter submitted is attached in Tab K. This data will be provided to NCDCM by the Town of
Sunset Beach.
NCDWR Pre -Filing Notification
• A scoping meeting was held at which DWR was present. The date of the scoping meeting was July
1, 2022, and this project was discussed. This meeting met the requirement for requesting a pre -
filing meeting under 40 CFR Part 121 for 401 Certifications in accordance with the federal Clean
Water Act.
• The project proponent hereby certifies that all information contained herein is true, accurate, and
complete to the best of my knowledge and belief.
• The project proponent hereby requests that the certifying authority review and take action on
this CWA 401 certification request within the applicable reasonable period of time.
• A Section 401 Pre -Filing Notification for the proposed project modification was submitted to the
N.C. Division of Water Resources on April 17, 2023 as shown in Tab L.
M

Town of Sunset Beach Navigation Project
Mary's and Turtle Creek
Project Narrative (Revised November 3, 2023)
List of Tabs
Tab A
Agent Authorization
Tab B
Project Narrative
Tab C
Permit Drawings
Tab D
Sediment Chemical Analysis
Tab E
EFH Assessment
Tab F
Biological Assessment
Tab G
Manatee Avoidance Guidelines
Tab H
NMFS Recommendations
Tab I
SHPO Resource Review
Tab J
Previous Permits and Agency Scoping Meeting
Tab K
Adjacent Riparian Property Notice
Tab L
401 Pre -Filling Notification
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