20241349 Ver 1_MCAS CP NWP5 Supplemental_FINAL_20240930

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Developing a Regional Framework Using Sediment as a Nature -Based Solution (NbS) to Improve
the Resilience of Coastal Habitat at Marine Corps Air Station Cherry Point
Carteret County, NC
Location
Data Collection Activity
Latitude °N
Longitude °W
Croatan National Forest Beach
Elevations, vegetation
34059'8.44
76057'3.28
lots
Slocum Creek
Elevations, vegetation
34057'26.71
76053'50.78
plots, marsh sediment
sampling, accretion rates,
Acoustic Doppler
Current Profiler (ADCP)
Slocum Creek Airfield
Elevation transects,
34055'27.15
76054'20.72
ve etation assessment
MCOLF Atlantic
Acoustic Doppler
34053'51.82
76019'16.48
Current Profiler (ADCP)
Game Lands - Neuse River
Elevations, vegetation
350 0'5.61
76032'34.18
Shoreline
plots, marsh sediment
sampling, transducer
deployment
Game Lands — Tumagain Bay
Elevations, accretion
34056'52.47
76030' 18.08
rates, vegetation plots
Instrument Deployment: A lack of long-term water level and wave data is available around the field
study locations. Therefore, several pressure transducers and Acoustic Doppler Current Profilers (ADCP)
shall be deployed past MLLW (-2.08 ft NAVD88), or as close as possible while following the procedures
within EA's Corporate Standard Operating Procedure No. 075 for Safe Wading Operations found in the
Health and Safety Plan. The final locations of the transducers shall also consider field -based
characteristics, such as sediment type and available in -water infrastructure. It is anticipated that the
transducers will be placed within a PVC housing that is attached to an earth anchor screw. The earth
anchor screw will remain approximately I foot above the bed level. They will be marked with a buoy and
bright color tape for increased visibility and future recovery (setup shown in Figure 2). It is not anticipated
that the installed equipment would result in a hazard to vessels due to placement in shallow water
locations. A barometric pressure transducer shall also be installed on land at the same field study location
to collect barometric pressure for total pressure corrections.
The transducers will be deployed for up to a 6-month period to be collected in Spring 2025, with an initial
data download after approximately one month of data collection and a second data download/equipment
removal at a later date. Deployment locations can be seen in Figures 3, 4, and 6. The quantity, instrument
type and data collected is as follows:
• (1) RBRsol03 D 1 wave16
• (2) RBRduo3 T.Djwave16
• (4) Barometric pressure transducers
Data Collection: Existing elevations for each site will be collected at low tide along the proposed
transects using a Trimble R10 rover fixed to the top of a 2-meter (6.56 ft) surveyor rod. This topographic
data is useful for determining elevations that support the current habitat. Topographic data collecting will
also be used to ground truth existing LiDAR. Spot elevations and horizontal locations of key features will
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be collected using RTK GPS/GNSS survey equipment (RTK rover and base station or virtual reference
station). The data are referenced to NAVD88 and the North American Horizontal Datum of 1983
(NAD83). This data shall be taken for every site except for MCOLF Atlantic (Figure 1).
Along the elevation transects the field crew will also collect vegetation plot data to conduct a high-level
vegetation assessment including species identification and percent cover. Locations shall be chosen where
changes are seen in vegetation community type. The assessment shall be contained to a lm xlm staked
plot where each corner coordinate shall be recorded. Within each plot location, the field team will record
one random spot elevation, identify marsh habitat, and identify vegetation species. If changes occur within
the plot location, those changes will be identified and recorded. Incidental observations and the extent of
invasive plants shall also be recorded. Characterization of wildlife habitat features along the transects,
such as nests and/or feeding areas shall be documented and identified to the lowest taxon possible.
Accretion rates: To measure accretion at the Slocum Creek (Figure 3) and Game Lands (Figure 5) sites, a
sediment horizon marker will be established using a thin layer of feldspar placed in a selected plot.
Procedures for installing and monitoring accretion rates are derived from Callaway, Cahoon, and Lynch
(Callaway et. al 2013). The procedures for plot installation include the following:
1. Select the plot location and place a 50 x 50-centimeter polyvinyl chloride (PVC) quadrat to
delineate the boundaries of the plot. Sprinkle feldspar in a thin layer evenly across the entire plot
for uniform coverage. Any feldspar that attaches to plants should be shaken gently so that it
attaches to the sediment rather than the vegetation.
2. Mark the plot corners with PVC posts or stakes with colored flagging tape so that they may be
easily relocated. Mark the plot using the GPS unit.
Monitoring of the markers will be completed several times throughout the contract Period of
Performance, which ends in April 2026. Monitoring should occur seasonally to every 6 months.
Monitoring procedures are as follows:
1. Select four random core locations within the plot.
2. Insert the cryocorer into the sediment at the random core locations to a depth below the expected
location of the feldspar marker. Initiate the flow of liquid nitrogen from the dewar until the soil
around the bullet is frozen. Remove the bullet and surrounding frozen soil.
3. Scrape the frozen soil with a knife to easily identify the feldspar marker and the depth from the
sediment surface to the top of the feldspar layer around all four sides of the frozen sample using a
caliper or ruler.
4. If possible, return the frozen sample to the original sampling location.
Sediment samples: Sediment samples will be collected at sites shown in Figure 3 and 4 and shall be
tested to provide information on the erodibility of the marsh soils. Additionally, data regarding
geotechnical soil parameters will provide design information necessary to inform different types of NbS
alternatives. Sediment samples will be taken along the elevation transects. Samples will be taken with a
corer to document changes in sediment type. Additional sediment may be collected using small hand
shovels to meet laboratory testing quantity requirements. Cores at the marsh will be taken by the EA field
team along proposed transects depending on the vegetation variation seen on site. The minimum number
of cores taken along a transect shall consist of at least one at the edge of the marsh and one within the
marsh. The coordinates, elevation and final depth of each sample will be recorded with the RTK GPS.
Care will be taken to sample in an area that has not been disturbed or compressed by foot traffic. Cores
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will be collected using a Russian Peat corer (5 cm [2in] diameter, 50cm [19.6 in]) pushed into the marsh
sediment until the point of refusal. Cores will be photographed, measured and documented for length of
the core and depth of visually identified transition layers.
References:
Callaway, J.C., D.R. Cahoon, and J.C. Lynch. 2013. The Surface Elevation Table - Marker Horizon
Method for Measuring Wetland Accretion and Elevation Dynamics. Methods in Biogeochemistry of
Wetlands 10: 901-917.
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Figure 2. Transducer deployment method using PVC housing and earth anchor screws in shallow
water.
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FILE PATH: C:SUSERSVNILL W IASlpGCUTAENTSIIEG ACV MILD STUDY LGCATIG NS.pWG rLGCUM W ILL ALIS. IS BELLA Sf1WMN 1121 APA
Figure 3. Horizon marker plots, RBR instrument deployment, and data collection points at Slocum
Creek
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FILE PATH: C:%J SERS%W I LLAMS%D O C U ME N TS%LE GAC Y F E I LD STUDY LO CATI O N S. DWG [GAMELAN D S] WILLAMS, I SABE LLA SrN,20244.54 PM
Figure 4. Transducer instrument deployment and sediment sample locations at Carteret County
Game Lands.
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FILE PATH: C1USERS%IWILLLAMSDOCU MEN TS+LEGACYFEILD STUDY LOCATIONS. DWG [GAME LANDS(2)] WILLIAMS, ISABELLA St27l20245:03 PM
Figure 5. Horizon marker plot and data collection points at Carteret County Games Lands interior
location.
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FILE PATH. C:USE RSMLLIAMSID OCUMENTSLEGACY FEILD STUDY LOCATIONS.DYVG IMCOLFI WILLIAMS. ISABELLA b2&20249: 03 AM
Figure 6. Instrument deployment locations at MCOLF Atlantic.
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