Avon Narrative(30Jul2021).pdf

AVON VILLAGE BEACH NOURISHMENT
COUNTY OF DARE, NORTH CAROLINA
NARRATIVE DESCRIPTION OF PROJECT
Dare County (NC), as the Applicant, is proposing a beach renourishment project, which calls for
up to 1 million cubic yards (cy) of beach -quality sand to be pumped onto the 2.5-mile (13,200
linear feet) beach via offshore dredging scheduled to start the summer of 2022. The anticipated
average fill density (volume of nourishment per linear foot of beach) is -75 cubic yards per linear
foot (cy/lf) of shoreline. The purpose of the project is to restore sand losses due to chronic erosion
and to improve storm protection along the vulnerable section of the project area.
The Applicant and its authorized Engineer (Coastal Science & Engineering) had the official pre -
application meetings on 4 March 2021 with federal and state agencies in addition to other
individual meetings with resource agencies. The sign -in sheet is included herein as Attachment 1.
Initial guidance regarding preparation of environmental documents required by state and federal
resource agencies before, during, or after construction was received from the meeting. The
Applicant also requested Section 7 consultation under the Endangered Species Act at the earliest
time, along with instructions regarding endangered species monitoring requirements during
construction, and environmental sampling (if necessary) before and after construction
The Applicant submitted the DWR Pre -Filing Meeting Request Form on 14 June 2021 per the Clean
Water Act Section 401 Certification Rule (Attachment 2).
• 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.
Coastal Science & Engineering 1 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Introduction
Dare County encompasses -89 miles of ocean shoreline from the Town of Duck to Hatteras Inlet.
The northern 30 miles (on Bodie Island) includes (from north to south) the towns of Duck, Southern
Shores, Kitty Hawk, Kill Devil Hills, and Nags Head. There is a 5-mile undeveloped portion of Cape
Hatteras National Seashore (Seashore) at the southern end of Bodie Island. The southern -53 miles
on Hatteras Island encompass the National Seashore and the communities of Rodanthe, Salvo,
Avon (the proposed project site), Buxton, Frisco, and Hatteras (Figure 1). Approximately 16 miles
are developed and 38 miles are undeveloped along the oceanfront. In total, 50 percent of Dare
County's ocean shoreline is developed, and 50 percent is undeveloped and held in permanent trust
by the Cape Hatteras National Seashore.
Then a rrativeforthe proposed Avon beach nourishment project accompanies application forms and
drawings (sheets 01-13) and includes the following sections:
ProjectBackground..........................................................................................................3
Historicaland Recent Erosion Rates..................................................................................4
Beach Condition Survey in July 2020, Volumetric Analysis, and Project Formulation ............4
Alternatives..................................................................................................................... 6
ProjectDescription.......................................................................................................... 7
SedimentQuality and Compatibility.................................................................................. 8
(1) Beach Sampling..................................................................................................................8
(2) Offshore Borrow Area Sediment Quality and Compatibility Analysis ............................8
Cultural Resources Study in the Borrow Area..................................................................... 9
DuneManagement Plan.................................................................................................. 10
Methodsof Construction................................................................................................ 11
SupplementaryReports.................................................................................................. 12
ReferencesCited............................................................................................................ 13
Figures.......................................................................................................................... 14
Attachment 1 (Scoping Meeting Sign -Up Sheet)................................................................ 24
Attachment 2 (DWR Request Form for 401 Certificate)...................................................... 25
Attachment 3 (15A NCAC 07H.0312 - Effective 1 April 2021)............................................... 27
Coastal Science & Engineering Z Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Dare County, as the Applicant, proposes to place up to 1 million cubic yards (cv) of beach -quality
sand along a 13,200-foot (2.5-mile) length of the Cape Hatteras National Seashore in front of the
developed shoreline at Village of Avon (Figure 2). The average fill density is -75 cubic yards per foot
(cy/ft). Nourishment sand will be excavated from a -250 acre offshore borrow area located -2-3
miles offshore of Avon within state waters. Confirmed by reconnaissance vibracores and the final
twelve 10-ft long vibracores in the proposed borrow area, the Applicant proposes
an excavation depth of 10 feet in Borrow Area 1 (-150 acres) and 6 feet in Borrow Area 2
(-100 acres). The proposed borrow area contains approximately 3.4 million cubic yards of beach -
quality sand if the proposed excavation depths are permitted.
Project Background
The Village of Avon is one of seven historic villages on Hatteras Island situated adjacent to (and
within) the Cape Hatteras National Seashore (CAHA) between Salvo and Buxton around mile marker
36. It is an unincorporated community under the jurisdiction of Dare County with a 2010 population
of 776 permanent residents. South of the Tri-Villages of Rodanthe, Waves, and Salvo, past a
-11.5-mile stretch of the undeveloped Cape Hatteras National Seashore, Avon is considered the
largest and busiest of the Hatteras Island towns. There are another-20,000 feet (-3.8 miles) of the
CAHA between the south boundary of Avon and Buxton, the next village along the barrier island (see
Figure 1). Avon is bordered to the east by the Atlantic Ocean and to the west by Pamlico Sound,
with a total land area of -2.4 square miles, as shown in the location map. Avon's primary industry
is tourism, with hundreds of homes, dozens of motels, and campgrounds available for short-term
rentals. There are also facilities on the ocean and sound side to accommodate the recreational
fishing community, surfers, and boaters. NC Highway 12 is the main artery for public and emergency
vehicle access to the Avon, Hatteras Village communities, and National Seashore facilities.
Avon Ocean Pier is located close to the center of the village and provides a coastal landmark on
maps. The section of shoreline north of the pier has generally been relatively stable over the past
50 years (NCDENR 2012). In contrast, the -1.5 miles south of the Avon Pier have experienced
accelerated erosion in recent years (Figure 3). The dunes along this highly eroding section of the
beach have been washed away, and ocean waves have frequently washed over and flooded NC
Highway 12 during inclement weather events (Figure 4). This occurs not only in named storms but
also in common nor'easters and other winter storms. The County reported that "the overwash [on NC
Hwy 12] has impeded, and at times prevented, first responders from responding to emergencies; our sanitation
workers from picking up trash; the citizens ofAvon from performing normal daily tasks, such as attending doctor
appointments, buying groceries, attending community events, and the list goes on. In addition to the safety
issues, there has been flood damage to homes and businesses, and it has negatively affected our tourism
economy." (Source: Dare County's More Beach to Love at:
Coastal Science & Engineering 3 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

https://www.darenc.com/government/avon-beach-nourishment/avon-faq).
In response to the emergent need for beach restoration in Avon Village, Dare County completed a
feasibility study to assess erosion and formulate solutions along the Village of Avon in November
2020 (CSE 2020). This feasibility report evaluates the beach in detail upcoast and downcoast of the
critically eroded area to place the area in context and establish linkages with the sand sharing
system alongshore. It also provides several levels of beach restoration plans for different project
longevities.
Historical and Recent Erosion Rates
The NC Division of Coastal Management (NCDCM) reports official erosion rates ("setback factors")
for Avon in 2020 ranging from 2.0 feet per year (ft/yr) north of Avon Pier to 6.0 ft/yr along a -4,000 ft
section of beach south of the pier. Erosion reduces to 3.0 ft/yr at the south limit of the Village.
In the feasibility report, CSE analyzed historical shorelines for fourteen different dates (1852 to
2020) and determined that the critically eroded section south of Avon Pier has experienced erosion
as high as 16-20 ft/yr over the past 20 years (CSE 2020). Because state erosion rates average over
60+years, the official rate is lower but has been increasing with each update along south Avon. The
cause of accelerated erosion is unclear, but one factor is rhythmic alongshore sand waves spaced
-3000 ft apart that slowly migrate downcoast, producing systematic variations in beach width. The
trough (narrow dry beach area) of one such rhythmic sand wave has persisted south of Avon Pier in
recent years.
Beach Condition Survey in July 2020, Volumetric Analysis, and Project Formulation
CSE established a baseline and measured profiles every 500 ft alongthe shoreline from the dune line
to deep water (>30 ft below sea level) along the entire 18,000-ft (-3.4-mile) Avon Village in July 2020.
An additional5,000 ft of upcoast and downcoast shoreline into the Cape Hatteras National Seashore,
managed by the National Park Service (NPS), was also surveyed. It is believed that the July 2020 data
set is the first comprehensive data set for the beach condition of this area, and it provided the basis
for the proposed nourishment formulation along with the historical erosion analysis.
The calculation limits extend from the dune crest to the offshore depth of closure* at -24 ft NAVD,
representing where nearly all sand exchange across the beach occurs. Volume analyses were used
to determine the sand deficit south of the Avon Pier relative to healthy sections of beach north of
the Pier that contains a high protective dune and wide dry -sand beach.
['Depth of Closure is the approximate limit of measurable bottom change over particular time scales, and
it is where waves and currents have no measurable impact on bottom elevations. The calculation limits
from the dune to the depth of closure will be used by FEMA to determine sand volume losses after a declared
Coastal Science & Engineering 4 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

disaster under Category G - Public Assistance (FEMA 2020). Based upon historical profiles analysis in the
adjacent Buxton project area (USACE-USDOI-NPS 2015), the closure depth for the Avon project area should
be around -24 ft NAVD.]
Figure 5 illustrates the Digital Terrain Models (DTM) of the study area by color -coded, smooth -
contour maps. Light colors indicate the dune -beach zone and longshore bar; deep blue represents
water depths >30 ft. The bathymetry DTMs show relatively smooth, continuous morphology of a
longshore bar represented by a yellow -green color band (inside the 20-ft depth contour) along the
northern half of Avon. The longshore bar diminishes to the south, and an inshore bar develops in
shallower water.
Figure 6 shows unit volumes station by station using the July 2020 survey. The five reaches
delineated for the study area are marked in the figure, and the horizontal lines (in red) show the
average unit volume of each reach.
The present results indicate that Reach 4 has the lowest unit volume of 748 cy/ft, which is 128 cy/ft
less than Reach 3, 133 cy/ft less than Reach 5, 441 cy/ft less than Reach 1, and 472 cy/ft less than
Reach 2. These profile volume differences along Avon provide a basis for CSE's proposed
nourishment volume determinations. We used the results to determine the profile deficit with
respect to an ideal or target beach condition (CSE 2020).
All of the original Reaches 3 and 4, and parts of the original Reaches 2 and 5, are included in the
proposed project. Hereafter and in the project map/permit application drawings, the original Reach
3 and a few hundred feet of Reach 2 are referred to as Reach 3 (9,200 ft north of Avon Pier), and the
original Reach 4 and -1,000 feet of Reach 5 are now referred to as Reach 4 (4,000 ft south of Avon
Pier).
The long-term, historic erosion rates adopted for the project area is 140,000 cy per year. It would
take approximately 1 million cubic yards of sand to restore the 13,200-ft project area for five years
under normal weather conditions. This is the total nourishment volume proposed herein.
Coastal Science & Engineering 5 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Alternatives
Three alternatives have been evaluated for the proposed beach nourishment:
• Alternative 1- No -Action
• Alternative 2 - Nourishment with Offshore Sand Source and Winter Construction
• Alternative 3 - Nourishment with Offshore Sand Source and Summer Construction
Additional alternatives and other sand sources (material dredged from Avon Harbor and inland
deposits from nearby sand stockpiles) were initially considered during the feasibility study but were
dismissed for environmental, geological, technical, or economic reasons (CSE 2020).
Construction during the summer months is necessary in this setting because of high wave conditions
for the remainder of the year, as shown by other nourishment projects completed (or being planned)
in Dare County as listed in Table 1. The full scope of work proposed under Alternative 3 would best
protect NC 12 and NIPS facilities at Cape Hatteras. It would increase the area of sea turtle and
shorebird nesting habitat, and it would also reduce the frequency of future remedial or emergency
measures. The short-term biological impacts to benthic organisms under Alternative 3 may be greater
than Alternative 2. However, Alternative 2 would require work in the winter months, placing
Contractor personnel at much greater risk due to unsafe conditions offshore. Therefore, Alternative
3 is the Applicant's preferred alternative.
TABLE 1. Beach nourishment projects using offshore borrow areas completed or planned in Dare County.
Volume
CY)
Construction
Period(Million
Main
SponsorLocation
Nags Head
4.6
May -Oct 2011
County
Rodanthe
1.7
Jul -Sep 2014
NCDOT
Duck, Kitty Hawk, Kill Devil Hills,
and Southern Shores
3.8
May -Oct 2017
County
Buxton & Seashore
2.6
Jun 2017-Feb 2018
County
Nags Head
4.0
May -Aug 2019
County & FEMA
Duck, Kitty Hawk, Kill Devil Hills,
and Southern Shores
1-2
Summer 2022
County &FEMA
Nags Head
0.567
Summer2022
FEMA
Buxton & Seashore
1.2
Summer 2022
County & FEMA
Avon
1.0
Summer 2022
County
Coastal Science & Engineering 6 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Project Description
Based on the feasibility study (CSE 2020) and available funds, Dare County has elected to nourish
the critically eroded section of beach and its immediate upcoast. The proposed project area,
marked as Reaches 3 and 4 in Figures 7 and 8, is 13,200 ft (2.5 miles) out of the 18,000 ft (-3.8 miles)
oceanfront of the Avon Village. The maximum nourishment volume will be 1 million cubic yards. It
will involve excavating beach -quality sand from an offshore borrow area via hydraulic and/or
hopper dredge (see Figure 2). Borrow sediment will be pumped to the beach and spread by land -
based equipment (eg - bulldozers) in the beach zone between the toe of dune/mid-dry sand beach
and the low watermark. The elevation of the nourishment berm will be set at or below the normal
dry -beach level (approximately +7 feet NAVD) so that it is naturally overtopped by waves during
minor storms. The nourishment profile will be designed to adjust rapidly to changing wave
conditions with an expected gradual shift of sand into deeper water as the profile equilibrates.
Backshore areas are expected to be enhanced gradually after construction by natural dune building
processes.
The average maximum fill density (volume of nourishment per linear foot of beach) will be -75 cy/ft.
This is equivalent to an average beach width increase after natural profile adjustment of -40 ft in
Reach 3 and 90 ft in Reach 4. During construction for a 2.5-mile-long project, the anticipated
maximum impact area is -100 acres. The maximum project is expected to create
-15 acres of new dry -beach habitat. This expanded dry -beach area will eventually produce -3.5 acres
of new dune habitat via natural processes after the equipment is removed from the beach. The
maximum scale is expected to provide approximately five years of erosion relief, dune growth, and NC
12 protection under normal conditions. The final project volume will be determined according to the
state and federal permits, the County's construction fund, and the responsible bid.
Fill densities will vary from 43 cy/ft in Reach 3 (north of the Avon Pier) to 90 cy/ft in Reach 4 (south of
the Avon Pier) to best achieve the Applicant's purpose and goals of the proposed nourishment
project. Figure 9 includes the fill design of two representative stations, and the details of the design
are illustrated in Permit Drawing Sheets 03-10. The elevation of the dry -sand berm is set to be at
+7 ft NAVD, and the initial dunes will be constructed along Reach 4 from stations 1590+00 to 1682+00.
The dune crest is set to be at+13 ft NAVD, the typical dune width is 20 ft, and the dune seaward slope
is 1 on 3 (vertical versus horizontal). The width of the constructed dry -sand berm (before normal
profile adjustment) in front of the toe of the initial dunes varies from 100-200 ft. The initial dune will
tie into the existing profile but will not encroach on existing vegetation or house foundations under
any circumstances.
Coastal Science & Engineering 7 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Final fill templates for each section of the beach will be determined close to the time of construction
(according to standard practice) based on beach conditions. These will be submitted to the
permitting agencies for approval prior to the commencement of nourishment. However, the total
project volume and the impact area will not exceed the maximum values proposed herein.
Sediment Quality and Compatibility
(1) Beach Sampling
CSE established five stations in 2020 along the proposed project area while conducting the
feasibility study (CSE 2020). Sediment samples were collected at 14 positions across each station
in March 2021. The location of the five alongshore stations are shown in Figure 10, and the
14 positions across each station are illustrated in Figure 11. The mean grain size of beach sand at
the Avon project area was 0.289 millimeters (mm) with 4 percent of shell, 1.7 percent granules (2
to 4 mm), and 0.1 percent of gravel (4 to 76 mm) as of March 2021. Samples collected below -8 ft
NAVD were finer than those collected from the upper portions of the profile. Samples collected
within the trough (next to MLW in Figure 11) were significantly coarser. The mean grain size of
samples collected above mean low water (MLW) is 0.323 mm with 4 percent shell material and 1.8
percent gravel (>2 mm) by weight. Not including the trough, beach samples contained -2-3 percent
shell material, 1.7 percent granules (2 to 4 mm), and almost no gravel by weight.
(2) Offshore Borrow Area Sediment Quality and Compatibility Analysis
The proposed offshore borrow area encompasses -250 acres and is located within NC state
waters. Fifteen (15) 3-inch borings were obtained in April 2021, and each core has a uniform depth
of 10 ft below the existing substrate. Twelve out of the 15 cores are located in the proposed borrow
area, yielding an average core density of one core per -20 acres. The core locations are marked in
Figures 2 and 12, and on Permit Drawing Sheets 11-12. The borings were split, logged, subsampled,
and analyzed for grain -size distribution and comparison with the existing beach sand, then pro-
rated according to the length of each sample interval. This allows the calculation of boring statistics
to a specified "composite" depth, which is useful for the operational considerations of dredge
vessels. After calculating the composite values to 6 ft, 8 ft, and 10 ft depths, seven borings were
found to have beach -quality sand to a depth up to 10 ft in Borrow Area 1, and five borings were
found to have beach -quality sand to a depth up to 6 ft in Borrow Area 2.
The mean grain size of the seven borings in Borrow Area 1, composited to a 10-ft depth, is 0.308
mm with 16.4 percent shell material, 2.6 percent granules (2 to 4 mm), and 0.2 percent gravel (4 to
76 mm) by weight.
Coastal Science & Engineering 8 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

The mean grain size of the five borings in Borrow Area 2, composited to a 6-ft depth, is 0.331 mm
with 16.8 percent shell material, 5.1 percent granules, and 0.7 percent gravel by weight.
Overfill factor provides a measure of how a particular sand source will perform as beach
nourishment. Low overfill factors are generally preferred, with the ideal being equal to 1.0. The
overfill factor of Borrow Area 1 (10-ft cut depth) is 1.0, and 1.1 for Borrow Area 2 (6-ft cut depth),
indicating a good match between the material in the borrow areas and the native beach.
The boring density in both Borrow Area 1 and Borrow Area 2 is approximately 1 core per 20 acres.
Based on these descriptive statistics, the proposed borrow area contains compatible sand (Figure
13) and meets the requirements of the updated North Carolina Technical Standards for Beach Fill
Projects (15A NCAC 07H .0312 effective April 1, 2021 -Attachment A) and National Park Service
Sediment Management Framework (NPS 2021a and 2021b).
The proposed 250-acre borrow area would provide up to 3.4 million cubic yards of beach -quality
sand if excavation is permitted to a depth of 10 ft in Borrow Area 1 and 6 ft in Borrow Area 2. More
details of the geotechnical data and analysis are included in AppendixA - Littoral Processes of the
Environmental Assessment.
Large sediment sampling was conducted in March 2021 as required by North Carolina sediment
standards for the proposed beach nourishment (15A NCAC 07H.0312 Effective 1 April 2021).
The fieldwork, data analysis, photo processing, and the report were performed under
Grant Contract No. CW20490 between the North Carolina Department of Environmental Quality
and the County of Dare. Large clasts are defined as sediments greater than or equal to one inch
(25.4 millimeters) in diameter, and shell material greater than or equal to three inches
(76 millimeters) in diameter. Survey results show that 26 clasts were observed along the five
transects in the Avon project area in March 2021. Each transect averaged 5.2 shell fragments
greater than three inches in diameter. More details and the full conclusions are included in
Appendix C - Large Sediment Sampling Report of the Environmental Assessment.
Cultural Resources Study in the Borrow Area
The coastal waters off the Outer Banks of North Carolina have one of the highest documented
concentrations of shipwrecks in the western Atlantic. Hundreds of vessels have been reported lost
off the Outer Banks and especially off Cape Hatteras. Weather, currents, natural magnetic
anomalies, and shoals make navigation along the Outer Banks and off Cape Hatteras more
hazardous than in most East Coast areas.
Although the proposed action area lies within this area, no shipwreck remains have been
documented on the adjacent beach or in the offshore vicinity (USACE-USDOI-NPS 2015).
Coastal Science & Engineering g Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

A submerged cultural resource remote -sensing survey of the proposed borrow area was conducted
by Tidewater Atlantic Research (TAR) of Washington, North Carolina. Field work was completed by
24 July 2021, and the results and findings are included in Appendix G - Cultural Resources Survey of
the Environmental Assessment. Work performed by TAR consisted of a background literature survey,
historical research, and cartographical investigation. Field investigations identified three magnetic
anomalies inside the proposed borrow area, and three within the 200-ft perimeter of the borrow
area. All six anomalies represent very small ferrous objects. None appear to represent a potentially
significant submerged cultural resource and therefore, no avoidance was recommended. Analysis
of the acoustic data identified no evidence of sonar targets in the borrow area or its immediate
vicinity. Consequently, no potentially significant submerged cultural resources will be impacted by
dredging in the proposed borrow area or its adjacent 200-ft buffer.
Dune Management Plan
Dare County proposes to integrate a dune management plan into the proposed nourishment
project. The purpose of the plan is to improve storm protection along the vulnerable section of the
project area, accelerate dune growth, and provide guidance for possible sand relocation activities
in the event of future sand encroachment to existing structures.
The dune management plan proposed as part of the nourishment plan and present permit
application includes the following actions at two major stages:
(1) During Construction - Initial dunes are proposed to be built along Reach 4 - south of
the Avon Pier. The typical elevation at the top of the dune will be +13 ft NAVD, and the
typical width of the dune crest will be 20 ft. The typical seaward slope will be at i on
3 (vertical versus horizontal). The constructed berm width in front of the dune varies
from 100-200 ft, providing sufficient dry -sand beach to minimize scarping at the toe of
the dune following project completion. The protective dune will tie into the existing
profile but in no circumstance encroach on existing vegetation or house foundations.
(2) Following Construction - Sand fencing will be installed on the newly constructed
dune crest as close to the stable vegetation line as practical. Vegetation will be
planted along the entire project area (ie - Reaches 3 and 4) following nourishment.
General instructions are illustrated on Permit Drawing Sheet 13, and the exact
locations of sand fencing and vegetation will be determined based on conditions after
the proposed renourishment.
Coastal Science & Engineering 10 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Methods of Construction
The proposed beach renourishmentwiII be placed by ocean-going trailing suction hopper dred ge(s)
or cutterhead pipeline dredges) between the seaward crest of the existing dry beach and the outer
bar. Only the profile above high water is controllable in nourishment construction. Intertidal and
underwater portions of the profile will be subject to natural adjustment by waves. The fill will be
placed no higher than +7 ft NAVD (the average natural elevation of the berm).
Work will progress in sections within the borrow area and along the beach. Fill placement along the
beach will typically progress at an average rate of 300 ft per day. Construction activities will involve
the movement of heavy equipment and pipe along-4,000-ft sections over a period of
1-2 weeks. Once a section is complete, piping and heavy equipment will be shifted to a new section,
and the process will be repeated. As soon as practicable, sections will be graded and dressed to
final slopes. Beach residents along the project area will experience construction -related disruption
for only seven days or less, other than at equipment staging areas.
Land -based equipment will be brought to the site over public roads and will enter the beach at
designated beach access areas. Any alteration of dune vegetation/topography necessary for
equipment access will be authorized prior to undertaking any work and be repaired to pre -project
conditions. Daily equipment staging will be on the constructed beach seaward of the dune line.
Existing dunes and vegetation on the beach will be avoided and preserved. The Contractor will
provide properstorage and disposal of oils, chemicals, hydraulic fluids, etc. necessary for operation
according to state and federal regulations.
Construction Schedule — The proposed project will require summer dredging because of safety
issues, particularly the lack of a nearby safe harbor for ocean dredges. Construction duration is
expected to be a maximum of -3 months if work is permitted between 1 May and 15 September.
CSE evaluated potential cost savings during the feasibility study should an Avon nourishment
project using offshore deposits be combined with similar work at Buxton (CSE 2020). Some sharing
of mobilization costs would potentially offer savings of $2-3 million for the proposed project.
Permit applications for the Buxton renourishment project were submitted to the state and federal
agencies at the same time as the Avon project, targeting construction in summer 2022. Therefore,
the preferred schedule for the proposed Avon nourishment is summer 2022. The summer
construction proposed herein is consistent with all prior nourishment projects in Dare County since
2011 (see Table 1). It also follows the Applicant's goal of maintaining the project with
renourishment at approximate five-year intervals between projects.
Coastal Science & Engineering 11 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Supplementary Reports
The following reports are prepared in support of the permit application:
Appendix A) Geotechnical Data Analysis — Contains geotechnical data on the proposed borrow
areas and the beach before the proposed renourishment. Detailed results of beach sampling and
borrow -area coring are presented, including the large sediment sampling results. The Technical
Standards for Beach Fill (15A NCAC 07H.0312 Effective 1 April 2021) were followed.
Appendix B) Monitoring and Mitigation Plan — This plan is based on similar special conditions
prescribed for beach nourishment during the summer months in North Carolina at Nags Head,
Rodanthe, and Buxton. It describes the anticipated monitoring and protection measures for the
proposed nourishment action. Sampling stations and data analysis methodology for the ecological
survey required by NPS is included.
Appendix C) Large Sediment Sampling — Contains large sediment survey stations, photos, and
data analysis of the large sediment sampling required by NCDEQ under Technical Standards for
Beach Fill (15A NCAC 07H.0312 Effective 1 April 2021).
Appendix D) Littoral Processes — Provides detailed discussion and additional data analyses of
erosion, wave climate, and littoral processes in the proposed Avon project area and the predicted
performance of the proposed renourishment project.
Appendix E) Biological Assessment — Analyzes the potential effects of the proposed nourishment
on federally listed threatened, endangered, candidate animal species (wildlife, invertebrates, and
fish) or plant species, and designated or proposed critical habitats pursuant to Section 7 of the
Endangered Species Act of 1973 (as amended).
Appendix F) Essential Fish Habitat Assessment (EFH) — Evaluates the impact of the proposed
nourishment to essential fish habitat or habitat areas of particular concern for those species
managed by the South Atlantic Fisheries Management Council and Mid -Atlantic Fisheries
Management Council.
Appendix G) Cultural Resources Survey — Provides the methodology and results of a submerged
cultural resource, remote -sensing survey of the proposed borrow area and identifies any magnetic
anomalies in those areas.
Coastal Science & Engineering 12 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

References Cited
CSE. 2020. Phase 1 Feasibility Report - Shoreline Erosion Assessment and Alternatives for the Avon Beach Restoration.
Report for County of Dare, NC; CSE, Columbia, SC,103 pp plus appendices.
FEMA. 2020. Public Assistance Program and Policy Guide V4.0. Federal Emergency Management Agency, Washington,
DC, pp 221 + 14 appendices.
NCDNR/NCDENR. 2012. North Carolina 2011 long-term average annual oceanfront erosion rate update study methods
report. NC Department of Environment and Natural Resources, Division of Coastal Management, Raleigh, 125 pp.
NIPS. 2021a. Cape Hatteras National Seashore Sediment Management Framework - Final Environmental Impact
Statement. National Park Service, Fort Collins, CO, 50 pp + appendices.
NIPS. 2021b. Joint Record of Decision Sediment Management Framework - Cape Hatteras National Seashore. National
Park Service, Fort Collins, CO, 13 pp + appendices.
USACE-USDOI-NPS. 2015. Environmental assessment — beach restoration to protect NC Highway 12 at Buxton, Dare
County, North Carolina. US Army Corps of Engineers, US Department of Interior, National Park Service, NIPS
603/129663, Volume 1 (204 pp) and Volume II (Appendixes A to G).
Coastal Science & Engineering 13 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

V N 0 5 10 20
� o Miles
Duck
Southern Shores s
a Kitty Hawk
Albemarle Sound Kill Devil Hills �
Dare County, NC
Nags Head
a
Cape Hatteras
National Seashore
Souied O
Orcgon Inlet
Alligator River
National
Wildlife Refuge
0
Rodanthe
Waves
Salvo
Cape Hatteras
National Seashore
Avon
Project Site
Buxton
Frisco
Pair7f eo Soured Hatteras,
Site Coordinates
Hatteras Inlet Latitude: 35' 20' 50" N
Ocracoke Longitude: 750 30' 5" W
FIGURE 1. Location of Avon and Cape Hatteras National Seashore, Dare County, North Carolina.
Coastal Science & Engineering 14 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Pamlico Sound
Cape Hatteras
National Seashore
Atlantic Ocean
?550f00
M � U
p O
Avon Pier — U)
1590+00 c
L U
-Q
v U
W
4 0
RU a
�o y
�o 0
L0
N
Cape Hatteras &82+00
National Seashore
•
•
•
• Proposed
• Borrow Area
• 10-ft Cores in the 10-ft cut area
• 10-ft Cores in the 6-ft cut area
• Cores during sand search
0 3,000
Scare (Feet)
FIGURE 2. Proposed beach nourishment at Avon showing the project limits and offshore borrow area. Core
locations are marked on the figure. All cores have a uniform length of 10 ft.
Coastal Science & Engineering 15 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

• � � ., III
FIGURE 3. Aerial photo taken on 15 July 2020 showing the highly eroded section of Avon (Reach
4). The ground photo was taken by Daniel Pullen on 20 September during Hurricane Teddy. NC
Highway 12 was closed for 5 consecutive days due to overwash caused by ocean swell generated
by Teddy.
FIGURE 4. Ground photo taken by Daniel Pullen in front of Supermarket Food Lion. It shows the
frequent flooding and un-accessible road condition of NC Highway 12 at Avon.
Coastal Science & Engineering 16 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

14sa+oo
Cape Hatteras
National Seashore
rr
ri
li
I f:
Pamlico Sound ;J
r r.
rr
1500s0p r
1I "!
rl I�
+ 1 Nrl
r1 „
f' I!
f rr
rll r
IIlf
r 1550+00 I'l
1!
� 1
r ,
f,
- rr
II
1!
I� 1
1.
1600+00 1
I�
I�
�P
Avon ;
,I
1 r
f L
1 +
} Ij
r I,
r +
! I
1sso+oo +I +
1 r
I f
r r
r 1
+ r
Iti�+ r
Ir �
Village r
r f
Limit I
1
t
17a0+00 _
1470+o0
1500+00
1555+00
1590+00
C
U
0
N FT NAVD
J 20 R
10 ft
Oft
1 O rt
12 1700+00 0 3,000
Cape Hatteras Scale
NAD83 North Carolina State Planes, US Foot
National Seashore NAVD'88 ft -40 8 L
FIGURE 5. Color -coded topography and bathymetry Digital Terrain Models (DTM) from the July 2020 beach
condition survey for the Avon study area. Note: the proposed nourishment project area is from stations
1550+00 to 1682+00, mainly along Reaches 3 and 4.
Coastal Science & Engineering 17 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Unit Volume From Dune Crest to -24 ft NAVD
2000
I I I I
1800
I I I I
Reach 1 Reach 2 Reach 3 Reach 4 Reach 5
1600
3,000 ft I 5,500 ft I 3,500 ft I 8,000 ft I 3,000 ft
I I I I
1400
I I I I
I I I - I
E1200
X I-
a
Avg=122D cy/ft i
1000
I I -
D
vg=1189 cy/ft I I I
I
WOI
I I Avg=748 cy/ft I Avg=881 cy/ft
Avg=876 cy/ft
I I I I
600
I I I I
I I I I
400
I I I I
1470+00 1500+00 1555+00 1590+00 1670+00 1700+00
Station
FIGURE 6. Unit volumes by station from the foredune to the approximate depth of closure at —24 ft NAVD
along the Avon study area using the July 2020 survey. Note: the proposed nourishment project area is from
stations 1550+00 to 1682+00, mainly Reaches 3 and 4.
Coastal Science & Engineering 18 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

FIGURE 7. Aerial photo taken on 15 July 2020 showing the proposed project area, particularly
Reach 3 - north of the Avon Pier.
FIGURE 8. Aerial photo taken on 15 July 2020 showing the proposed project area, particularly
Reach 4 - south of the Avon Pier.
Coastal Science & Engineering 19 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Avon Station 1560+00
16
t
^ July 2020 Profile
10
Fill Vol
5
>
♦
MHW
`
Z
♦
-----MLW-------
-5
O
V w
CO-10
W
-15
Berm Elevation +7.0 ft NAVD
Berm Width 42 ft
-20
Fill Density 30 cylft
-25
400 600
800 1000 1200
1400 1600
Distance from Baseline (ft)
Avon Station 1610+00
15
Profile
1 — — July 2020
10
t Fill Vol
.-. 5
i r
❑
t
♦ MHW
Z
♦ MLW
5
10
W -15
Berm Elevation +7.0 ft NAVD .
Berm Width 164 ft .
Fill Density 90 cy/ft
-20
Typical Dune Width 20 ft
-25
200 400 600 800 1000 1200
Distance from Baseline (ft)
FIGURE 9. Representative fill templates at station 1560+00 for Reach 3 and 1610+00 for Reach 4. Beach
profiles represent the beach condition in July 2020. An initial dune is proposed to be constructed along
portions of Reach 4. The dune crest is set to be at +13 ft NAVD and the seaward slope is 1 on 3. The typical
dune crest width is 20 ft, and the constructed dry -sand berm in front of the dune is approximately 164 ft at
station 1610+00 (-2,000 ft south of Avon Pier).
Coastal Science & Engineering 20 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

:.ape HaVeras National Seashore
Pamlico Sound
16zo+on
1540+00 _
C
taut
Avon yszo+c
12
11640+00
- 1660+00
9680+00
Village Limit
Village Lmrt
Atlantic Ocean
Avon Pier
1 0 2,000
Cape Hatteras National Seashore
Scale (Feet)
FIGURE 10. Location of the five sediment
sample transects (14 samples per transect)
along the Avon project area. Samples were
collected in March 2021.
Dune Toe Sediment Grab Sample Positions
ton - - Berm Crest (Typical Beach Profile)
Berm ) MHW
Oft ------------- 1% MTL
MLW Bar _8
-loft ---------------------- ---- --- ------- -------- -12
Trough -1 6
-20
-loft ---- --- - - --- --- --- --- --- -- - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - 24
-30 ft
506 ft 1000 ft 1500 ft 200D ft 2500 n
FIGURE 11. Sample positions for "beach" grab samples along the Avon project area following North Carolina
sediment sampling criteria rules. The Avon littoral profile exhibits a narrow berm (dry -sand beach) and deep trough
separating the outer bar from the beach. Elevations and depths (v-axis) are relative to approximate Mean Sea Level.
Coastal Science & Engineering 21 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina

Borrow Area 1(10 ft cut)
Boring
Mean MM
Shell %
Gravel %
Granulemm %
AV-21
0.267
15.4
0
1.9
AV-22
0.36
17
0
2.8
AV-25
0.287
13.5
0
2.1
AV-26
0.275
13.4
0
1.2
AV-27
0.376
14.1
0
1.5
AV-28
0.222
11.1
0
1.9
AV-29
0.411
30.6
0.8
7.0
*AVERAGE
0.308
16.4
0.1
2.6
Borrow Area 2 (6 ft cut)
Boring
Mean MM
Shell %
Gravel %
Granule
mm %
AV-16
0.551
28.3
2.6
12.1
AV-17
0.258
10.7
0
1.9
AV-18
0.226
14.4
0
1.9
AV-19
0.267
15.8
0
2.6
AV-30
0.467
23
0.9
7.3
Atlantic Ocean
• AV23
*AVERAGE 1 0.331 1 16.8 0.7 5.1
• AV20
i
* Averages are cwmposited to the proposed cut depths
of 10 ft in borrow area 1 and 6 ft in borrow area 2.
• AV29
0.411
30.6
7.9
0 AV19 *AV21
0.267 i 0.267
15.8 15.4
2.6 1.9
AV30
0.46767 �-
23.0 f AV18 Borrow Area 2
�'a 516 ss 10426 (6-ft Cut)
28,3
14.7'�. 1.9
i
i
• AV17
0.258
10.7
1.9
AV24
Borrow Area 1
f(10-ft Cut)
• AV28
0.222
• AV27 \
11.1
1.9
0.376
AV25
14.1
0.239
1.5
13.5
2.1
• AV22
b 360
17.0,
2.8
AV26
0.275
13.4
1.2
0 1,200
Scale (Feet)
FIGURE 12. Mean grain size, percent shell, and percent gravel for core composite samples to 10 ft in the proposed
offshore Borrow Area 1 and 6 ft in the proposed Borrow Area 2 based on borings obtained in April 2021. Each boring
has a uniform length of 10 ft. Composite results of the twelve vibracores are listed in table on the upper right.
Coastal Science & Engineering 22 Permit Application - Narrative
Avon Village Beach Nourishment Dare County, North Carolina

104
90
80
70
60
0
o� 50
40
30
20
10
0
-4
Grain Size Distribution
Grain Size (mm)
8 4 2 1 0.5 0.25 0.125
-3 -2 -1 0 1 2 3 4
Grain Size (0)
Grain Size Distribution
Grain Size (mm)
Project CSE 2525
Location Avon (NC)
Date June 2021
Beach Mean
0.289 mm
Beach STD
0.521 mm
Beach Skew
-1.384 mm
Beach Kurt
6.120 mm
Beach Shell
12.3%
BA 10 ft Mean
0.308 mm
BA 10 ft STD
0.494 mm
BA 10 ft Skew
-1.048 mm
BA 10 ft Kurt
5.393 mm
BA 10 ft Shell
7.2%
Project CSE 2525
Location Avon (NC)
Date June 2021
Beach Mean
0.289 mm
Beach STD
0.521 mm
Beach Skew
-1.384 mm
Beach Kurt
6.120 mm
Beach Shell
12.3%
BA 6 ft Mean
0.331 mm
BA 6 ft STD
0.385 mm
BA 6 ft Skew
-0.991 mm
BA 6 ft Kurt
4.770 mm
BA 6 ft Shell
7.2%
FIGURE 13. GSDs for Avon native beach samples (n=70) compared with offshore samples in the
proposed borrow area (composite). [UPPER] Borrow Area 1 where 10 ft excavation depth is
proposed. [LOWER] Borrow Area 2 where 6 ft excavation depth is proposed. In both borrow areas,
sediments are expected to be coarser than the native beach initially. Over time, the grain size of
the post -nourishment beach is expected to move closer to the historical grain size distribution
around Avon.
Coastal Science & Engineering 23 Permit Application — Narrative
Avon Village Beach Nourishment Dare County, North Carolina