20171114 Ver 1_MHB Supplemental Info & MCBCL Letter2017_20170831

Mile Hammock Bay Marsh Pond Dredged Material Application Research Project
NOAA NCCOS Beaufort Lab
August 2017
Background:
The National Oceanic and Atmospheric Administration (NOAA) National Centers for Coastal Ocean
Science (NCCOS), Beaufort Lab has participated in a Department of Defense (DOD) -funded Research
Program on Marine Corps Base Camp Lejeune (MCBCL) since 2007. The focus of NOAA's research was to
examine the impact of sea level rise and climate -related drivers on salt marsh habitat, identify the role
of salt marshes in protecting MCBCL natural resources, and develop adaptive management strategies to
promote the long-term integrity of marsh habitat. As a result of this effort, NOAA researchers identified
several issues threatening the future viability of salt marsh habitat located adjacent to the Atlantic
Intracoastal Waterway (AIWW) (See Figure 1, Location Map).
Fragmentation of marsh habitat has been identified in the Mile Hammock Bay (MHB) area, which lies
between the New River Inlet and the MHB boat basin. Research demonstrates that since 1989, the
marsh to open water ratio in this area has declined. Examination of aerial photography demonstrates an
increase in the size of marsh ponds, and an 8 -year monitoring program documents a significant marsh
dieback, resulting in extensive areas of bare ground. In addition, shoreline erosion along the AIWW since
its establishment in 1938 has resulted in a doubling of the waterway's initial width, from approximately
210 feet wide to an average of over 425 feet wide (DCERP Coastal Wetlands Final Report 2013).
Together, these processes of pond formation and shoreline erosion result in an increased loss of marsh
habitat via conversion to open water'.
One method of potentially slowing marsh wetland loss is to artificially supply sediments by spraying a
sediment slurry over eroding/subsiding marshes using a hydraulic dredge. The methodology is known as
thin -layer placement (TLP) of dredged sediment and has been tried on numerous occasions nationwide
since the 1970's (Ray 2007). Recently there has been added interest in this approach, and both NOAA
and U.S. Army Corps of Engineers (USACE) have identified methods to utilize natural infrastructure for
coastal resiliency as a priority (Sutton -Grier et al. 2015, Bridges et al. 2015). What sets this project apart
from other TLP projects is that this would be addressing holes 18-24" deep in the marsh, rather than
elevating the entire marsh platform 6-12".
As a result of the research that's been underway since 2007, there are permanent marsh vegetation
plots and Surface Elevation Table benchmarks located within 325 feet of the proposed project area. In
addition, a temporary tide gauge in the MHB boat basin has been recording water level, temperature,
and salinity since 2008, and will be maintained through the life of this proposed project. Most recently, a
small-scale TLP project was permitted by the resource agencies in 2017 that allowed NOAA to place
dredged material onto experimental plots within the Freeman Creek marsh area (approximately 4 miles
to the north) to enhance coastal marsh resilience, helping it "keep up" with sea level rise. Material from
' Just in the last year, the marsh pond just north of Pond B has opened up to the AIWW. This is demonstrated in
Figure 2 (2017 imagery) and Figure 3 (2014 imagery).

the adjacent AIWW was dredged using 2 small diaphragm pumps and a thin layer of dredged material
was placed onto an area of subsiding marsh in the spring of 2017. The native vegetation (Spartina
alterniflora) is currently being monitored and has already responded positively to the application.
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Figure 1. Location Map, Mile Hammock Bay (proposed project area in red; DOD -funded study area in green)
The MHB boat basin supports numerous MCBCL amphibious training missions. MCBCL is in full support
of the effort as it will maintain their training environment by protecting the integrity of the adjacent
coastal marshes. A letter of approval signed by the Director of Environmental Management, John
Townson, is attached.
Existing Site Conditions:
Marsh ponds. The proposed project is located within the boundary of Marine Corps Base Camp Lejeune
in the Mile Hammock Bay salt marsh adjacent to the AIWW. Existing conditions on the site are
undisturbed coastal wetlands dominated by Spartina alternifora, with S. patens, Salicornia, and Juncus
occurring at higher elevations. The proposed project will occur at intertidal elevations, within S.
alterniflora habitat.
The two areas targeted for restoration are identified as Pond A and Pond B (see Figure 2). Pond A has an
area of 0.09 acre and is 30 feet from the shoreline, and Pond B is approximately 0.08 acre and is 50 feet
from the shoreline. Both ponds are approximately 300-350 ft from the center of the navigation channel,
200-250 ft from the edge of the setback, and within the USACE AIWW Right -of -Way (see Figure 3). The

borrow areas for the project will be located directly waterward of the marsh ponds towards the
navigation channel.
The ponds are located within an area of environmental concern (AEC) as defined by Section 113A-113 of
the North Carolina Coastal Area Management Act (CAMA). Specifically, the proposed project will be
occurring in the estuarine waters and public trust waters AECs.
The Division of Marine Fisheries (DMF) has classified the project area as Primary Nursery Area (PNA)
(15A NCAC 07H .0208(a)(4)) and secondary nursery areas defined by rule 15 NCAC 3N .0102(c). This area
is also Essential Fish Habitat (EFH) for Coastal Migratory Pelagics (king mackerel, Spanish mackerel,
cobia) and is considered a Habitat Area of Particular Concern (HAPC).
Submerged Aquatic Vegetation. Areas of SAVs are known to exist within 500 feet of the project area
northwest of Pond B (Figure 2). Submerged aquatic vegetation functions as habitat for many fish and
aquatic animals. The long grass -like blades of the grasses creates a forest that shelters young and adult
fish and invertebrates from water currents and predators. While some fish, turtles, and birds eat
submerged aquatic vegetation, others use submerged aquatic vegetation as a place to find food. Large
predatory fish such as trout, striped bass and flounder search submerged aquatic vegetation beds to
find food hiding among the vegetation. Young blue crabs, pink shrimp, and red drum utilize the structure
and density of submerged aquatic vegetation beds as a refuge to hide from predators. Bay scallops and
hard clams live in submerged aquatic vegetation beds and the sediment below. Spotted sea trout, grass
shrimp, and bay scallops spawn in submerged aquatic vegetation habitat.
Subtidal soft bottom habitat. Although soft bottom habitat is defined as "unvegetated" and lacks visible
structural habitat, the surface sediments support an abundance of microscopic plants called benthic
microalgae and numerous burrowing animals are hidden below the surface. Soft bottom represents an
important spawning environment for many fish. In estuarine waters, flatfish, clams, drum, spotted sea
trout, and blue crabs spawn. In oceanic soft bottom habitat, summer flounder gather to spawn during
the winter in locations where the tides and currents carry their young into protected estuaries.
Nearshore ocean waters in North Carolina also serve as important pupping grounds for several species
of sharks such as Atlantic sharpnose shark, bonnethead shark, and to a lesser extent, the blacktip shark
and scalloped hammerhead shark.
Oyster reef habitat. There is no oyster reef habitat present in either pond, as neither pond is connected
via a tidal creek to estuarine water.
The project is located within a section of the AIWW that is part of the White Oak River Basin. The NC
Division of Water Resources classifies the AIWW at the project site as SA; HQW. The classification
definitions are:
SA: Tidal salt waters that are used for commercial shellfishing or marketing purposes and are also
protected for all Class SC and Class SB uses. All SA waters are also HQW by supplemental classification.
HQW: Supplemental classification intended to protect waters which are rated excellent based on
biological and physical/chemical characteristics through Division monitoring or special studies, primary
nursery areas designated by the Marine Fisheries Commission, and other functional nursery areas
designated by the Marine Fisheries Commission.

Borrow Areas. The material used to fill Ponds A and B will be dredged from the AIWW directly adjacent
to each of the ponds (Figure 2). Water depth in the area to be dredged is expected to be between 6 —12
feet, and material within the upper 12-18 inches is expected to be predominantly sand. To verify this,
NOAA staff will perform grab samples of material in 3 locations in each of the dredge boxes, at which
time they will also record water depths. Sediment samples will be tested to determine the composition
of the material (percentage of sand versus silt).
Both dredge boxes are located in open water habitat approximately 100 feet from the shoreline and
approximately 150 - 200 feet from the ponds. There are no SAVs, oyster reefs, or soft bottom habitat
within the borrow areas.
Figure 2. Project Map, Pond A and Pond B targeted for restoration
Applicant's Stated Purpose and Need:
The applicant's stated purpose and need for this project is to demonstrate and test effectiveness of
applying dredged material to marsh ponds for research purposes and study their response. This one-
time application of material will increase "elevation capital" allowing the marsh to reach optimum
biomass, ameliorate shoreline erosion, and provide opportunity for understanding the effects of
material placement on the local marsh platform. The project is built upon a decade of research on
MCBCL coastal wetlands and local scientific expertise, providing a unique opportunity to scientifically
test the approach in a situation where the environmental and biological variables are well -understood.
One goal of the project is to provide the foundation for use of this technique in similar locations, by
developing a list of parameters and model predictions that are necessary for application of dredged
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sediment in coastal wetlands. This project will further enhance the partnership between NOAA, USACE
and MCBCL, and further each organization's goals and needs to promote coastal resiliency.
Project Description:
NOAA proposes to fill two ponds (Pond A and Pond B) with dredged sediment, bringing the surface
elevation up to that of the surrounding marsh, which is approximately 0 — 8" NAVD88. This is also the
elevation at which MHB marsh biomass is highest (Davis et al. 2017). After the elevation is restored,
Spartina alterniflora will be planted over the filled areas. The ponds are, on average, approximately 18-
24" deep. Filling of Pond A and B will require approximately 750 cubic yards of dredged material and
will cover approximately 0.17 acre (approximate volumes of Pond A and Pond B are 350 and 400 cubic
yards, respectively).
To minimize damage to the marsh surface, NOAA will install 12" -wide grated, fiberglass boardwalks over
the marsh to temporarily accommodate the dredge pipe and to facilitate monitoring. In addition,
temporary boardwalks consisting of planks attached to plastic crates, may be used during sediment
application and monitoring activities to minimize the impact of walking directly on the salt marsh.
Ponds A and B will receive material from borrow areas located directly waterward of the marsh ponds,
primarily within the USACE setback (Figure 3). The setback is a buffer area outside the designated
navigation channel that is not maintained by the USACE (undisturbed), and is water depth is
approximately 6-12' deep. Dredge boxes will not exceed 200' x 100' x 12-18" deep in both locations to
minimize impacts to benthic habitat. The dredge will be anchored within the borrow area with bow and
stern spuds while working sunrise to sunset, and at night it will dock at Mile Hammock Bay. Application
work is expected to take less than one week and will occur between November 16 and March 31 to
avoid impacts to fisheries within the PNA areas. NOAA staff will be present during work hours to
monitor and control the placement of material.
The dredge anticipated to do the proposed work is the SNELL, a multi-purpose vessel owned by the
USACE, Wilmington District. It is 104 ft in length and drafts 5' 6", making it very versatile for working in
shallow areas. It's known as the Swiss army knife of dredges, able to remove debris, wrecks and other
hazards from channels, perform vibracore sampling, bed leveling, marine construction (docks, piers,
pilings), construction of dikes and spillways, and dredging (clamshell and pipeline).
The SNELL is equipped with a 10" diesel -driven pump and a 6" hydraulic pump system that can discharge
up to 1,200 feet. A digging head lifts sediment off the bottom as the suction pump draws the material in
through the pipe and discharges it through the opposite end. The pipe will be floated from the vessel to
the shoreline, and once ashore, the pipe will be supported by the fiberglass boardwalk and, if necessary,
cradles made from lumber. A crib structure that will elevate the discharge end of the pipe above the
marsh pond will also be constructed of lumber. A diffuser will be fixed to the end of the pipe to spread
the material and diffuse the energy, and silt fencing and hay bales (if needed) will line the edges of each
pond to minimize impacts to the surrounding marsh. The dredged substrate is anticipated to have a high
sand content and therefore the activity is not expected to produce a plume of suspended fine
particulates in the project area.

Figure 3. Perspective of ponds and borrow areas from the USACE Navigation Channel (2014 imagery)
According to USACE sediment testing conducted in 1989 and 1996, material in the AIWW federal
channel within the project area consists of —97% sand. For this particular study, material will be taken
from just outside the navigation channel limits and will be primarily from the surface of the waterway
bed (within upper 18"). The material within both borrow areas will be sampled by NOAA (3 samples per
dredge box) and tested for percentage of sand versus fine-grained material (silt/clay). It is presumed
that the sediment make-up will have little effect on the marsh plants or their rate of growth; concern
only lies with the application process and turbidity levels that would ensue if material is more fine-
grained. As mentioned above, silt fencing and hay bales will be utilized to prevent sediments from
encroaching on marsh habitat adjacent to the ponds.
Once the elevation within the ponds begins to reach the elevation of surrounding marsh, the pumps will
be shut off and the pipe and cribbing will be adjusted to uniformly fill in remaining areas within the
ponds. The end result will be a leveled surface (as much as possible) to mimic the natural landscape.
Vegetation planting of Spartina alterniflora will occur in the spring following the fill activity (see Figure 4
for profile view of before and after project). Silt fencing will be removed once the vegetation is
established. If hay bales are used they would be expected to break down naturally over time.
Monitoring of both sites will begin in the spring and continue for at least three growing seasons, or until
Spartina alterniflora percent coverage equals 75%, which is the highest average annual coverage of S.
alterniflora recorded at the MHB monitoring site (DCERP Coastal Wetlands Report 2013).

Temporary Silt Fencing Planted Spartina alterniflora
A
' ' ' - Dredged
18-24 in — sediment
Marsh sediment
Figure 4. Profile view of pond before (left) and after (right) sediment application and planting.
Avoidance and Minimization:
Additional impacts were avoided by eliminating a proposed pond located approximately 400 ft
southeast of Pond A. This pond was considered "connected" and therefore more critical EFH, resulting in
the avoidance of 0.125 ac of marsh impacts. The ponds selected for this project are "isolated" from
open water and not directly accessible by fish or marine mammals, while also closest to the channel,
which reduces impacts of the dredge pipe and the need for additional boardwalk.
Material excavated for the ponds will be dredged from the setback area adjacent to the AIWW. Dredge
boxes have been established to minimize bottom disturbance and excavation depths will not exceed 12-
18". Placement of dredged material in ponds will not exceed the elevation of surrounding marsh to
avoid creating high marsh and introducing phrogmites.
The suggested November 16 — March 31 work window will be implemented to avoid impacts to fisheries
(finfish and shrimp). The dredge operator will abide by the USFWS manatee guidelines to avoid any
potential injury or harm to the protected species.
SAVs will be avoided to the maximum extent practicable; excavation will be within the setback of the
channel within waters too deep to support SAVs (typically 3 feet or less). Nearest SAV colonies identified
are 500 feet to the west of Pond B; nearest dredging will occur 150+ feet beyond SAVs.
Permanent impacts (fill) are designed to restore the sites to the original marsh elevation. A diffuser will
be fixed to the end of the pipe to spread the material and diffuse the energy of the dredged material
slurry. Temporary impacts during construction will not permanently alter wetland functions and;
therefore, will not be mitigated.
No Action Alternative:
It is the applicant's opinion that the only other potentially feasible alternative to the proposed project
(restoring marsh ponds to surrounding marsh elevation with material from adjacent channel) is the no -
action alternative, as discussed below.

The No Action Alternative: The No Action alternative would be the hands off approach or status quo.
NOAA will continue to monitor the marsh as they have been for the last ten years to determine if
shoreline erosion is occurring at the same or extended rate. The trend, as NOAA's research shows, is
that open water will eventually take over until little or no marsh is left (estimated to happen by 2100).
Currently, there is little completed research on marsh resiliency in North Carolina. Similar (TLP) projects,
on a much larger scale, are happening in other locations such as Avalon, New Jersey, Ocean City Harbor,
Maryland, Galveston, TX and New Orleans, LA. Within the past year, NOAA has applied for and received
permits to conduct a small-scale pilot thin layer project at Freeman Creek, which is approximately 4
miles northeast of the Mile Hammock Bay Site. Dredged material was placed in winter/spring of 2017
and is currently being monitored.
Resource Agency Coordination:
On April 16, 2016, NOAA hosted an onsite field meeting with USACE Planning and Environmental, NMFS,
and NCDCM to observe areas of study/erosion in the MHB area and to identify project areas that would
be acceptable for dredged material placement. Concerns by the agencies were raised regarding sites
that were directly adjacent to tidal creeks and project sites that expanded beyond permittable limits
(what was considered to be consistent with State/Federal laws).
On December 2, 2016 a pre -application meeting at Morehead City State Offices was held and included
USACE, NC Division of Coastal Management, National Marine Fisheries Service, NC Wildlife Resources
Commission, NC Department of Environmental Quality -Division of Water Resources, US Fish and Wildlife
Service and the MCBCL. Results of the meeting were two -fold: 1) to submit a Pre -Construction
Notification (PCN) for the small Freeman Creek pilot project (thin layer experimental plots) fitting terms
and conditions of NWP 18; and 2) to apply for an Individual Permit for this proposed project to fill marsh
ponds (<0.25 acre) at Mile Hammock Bay to ameliorate shoreline erosion along the AIWW adjacent to
MHB.
NOAA is concurrently applying for a Department of the Army (DA) Individual Permit and 401 Water
Quality Certification from NCDEQ-DWR. In addition to this, a Consistency Determination has been
submitted to NCDCM and an EFH Assessment has been submitted to NMFS. Additional resource agency
coordination will occur during public comment period of the DA permit process. All comments received
will be considered during development of the Environmental Assessment.
Cultural Resources:
The project site is not designated as a "Natural and Cultural Resources Area" (15A NCAC 07H .0501).
There are no listed historic properties or known cultural resources within the project's area of effect;
therefore, the project is not likely to impact cultural resources. Any cultural resources encountered
during construction would be protected and upon discovery, rapid coordination with the USACE and the
N.C. Department of Cultural Resources, Underwater Archaeology Unit would occur.

Endangered Species:
It is of the applicant's opinion that the proposed work may affect but is not likely to adversely affect
threatened or endangered species (West Indian manatee or sea turtles). No listed critical habitat exists
within the project area. Atlantic and shortnose sturgeon are not likely to be present in the project area.
The dredge SNELL is not confined to work within any specific moratoriums and does not require
additional precautions to operate. The September 2004 FONSI titled Use of Government Plant to Dredge
In Federally Authorized Navigation Projects In North Carolina determined that the side -cast dredge
MERRITT and small hopper dredge CURRITUCK cause no adverse effects to the natural environment, and
both of these dredges are larger and more powerful than the SNELL. Based on slow speed, small pipes,
and low suction, this dredge is not likely to adversely affect listed species, nor has it ever taken any
listed species.
Other Required Approvals:
401 Water Quality Certification, CAMA Federal Consistency concurrence, and NMFS concurrence of
Essential Fish Habitat Assessment.
Conclusion:
The proposed project conforms to the management objectives of 15A NCAC 07H .0203, 15A NCAC 07H
.0206, and 15A NCAC 07H .0209 as it will not adversely impact Estuarine Waters and Public Trust Areas.
The proposed project will not affect any wildlife recognized by the State as species of concern, will not
adversely impact water quality, and will result in minimal, temporary, and short-lived impacts to
fisheries and the aquatic habitat. The proposed project will be undertaken in compliance with all
conditions of DCM recommendations based on concurrence with the consistency determination.
Adherence to these conditions and recommendations will further minimize adverse biological and
environmental impacts to the maximum extent practicable.

References:
Bridges, T.S., Banks, C.J. and M.A. Chasten. 2016. Engineering with nature: Advancing system resilience
and sustainable development. The Military Engineer 699: 52-54.
Croft, A.L., Leonard, L.A., Alphin, T., Cahoon, L.B. and M. Posey. 2006. The effects of thin layer sand
renourishment on tidal marsh processes. Masonboro Island, North Carolina. Estuaries and Coasts
29:737-750.
Davis, J., Currin, C. and J. T. Morris. 2017. Impacts of fertilization and tidal inundation on elevation
change in microtidal, low relief salt marshes. Estuaries and Coasts DO1 10.1007/s12237-017-0251-0
DCERP Coastal Wetlands Final Report 2013. Chapters CW -1 and CW -2.
https://dcerp.rti.org/DCERPPublicSite/Ecosystem Modules/CoastalWetlands.aspx
Ray, G. 2007. Thin layer placement of dredged material on coastal wetlands: A review of the technical
and scientific literature. ERDC/EL TN -07-1.
Sutton -Grier, A., Wowk, K., and H. Bamford. 2015. Future of our coasts: the potential for hybrid
infrastructure to enhance the resilience of our coastal communities, economies, and ecosystems.
Environmental Science and Technology 51:137-148.
U.S. Army Corps of Engineers, October 1989. Environmental Assessment and Finding of No Significant
Impact (EA/FONSI): Maintenance Dredging of Atlantic Intracoastal Waterway.
U.S. Army Corps of Engineers, August 1996. Environmental Assessment for Maintenance Dredging of the
Atlantic Intracoastal Waterway Beaufort to Cape Fear River Reach Section II, Tangents F, G, and H.
U.S. Army Corps of Engineers, September 2004. Finding of No Significant Impact: Use of Government
Plant to Dredge In Federally Authorized Navigation Projects In North Carolina.
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UNITED STATES MARINE CORPS
MARINE CORPS INSTALLATIONS EAST -MARINE CORPS BASE
PSC BOX 20005
. � CAMP LEJEUNE NC 28542-0005
Dr. Carolyn Currin
NOAA NCCOS
101 Pivers Island Rd.
Beaufort, NC 28516
Dear Dr. Currin
5090.11
BEMD
JUL 2 1 ?M7
Marine Corps Installations East -Marine Corps Base Camp
Lejeune (MCIEAST-MCB CAMLEJ), Environmental Management Division
has reviewed your thin -layer sediment application project.
Your previous nine years of coastal marsh work aboard MCIEAST-
MCB CAMLEJ have identified the vulnerability of salt marshes
located adjacent to the Atlantic Intracoastal Waterway and we
support efforts to increase coastal resiliency.
MCIEAST-MCB CAMLEJ supports the proposed project to fill two
ponds with dredged sediment at the Mile Hammock Bay area, thus
bringing the surface elevation back up to that of the
surrounding marsh, and planting those areas with marsh
vegetation. In addition, we support future monitoring of these
areas to assess the impact of the action. These wetlands are
important natural resources and provide crucial protection to
the coastal ecosystem in support of the Marine Corps' training
mission.
Please be aware that access to MCIEAST-MCB CAMLEJ is subject
to mission needs and is subject to change on short notice.
Military or natural resources activities will not be altered to
facilitate your activities.
Mr. Martin Korenek is your main point of contact and can'be
reached at (91.0)451-9384 or [e-mail].
Sincerely,
12 girls. ik
OHN R. TOWNSON
Director, Environmental Management
By direction of the
Commanding General