HomeMy WebLinkAboutAPPENDIX G - Cultural Resources SurveyAPPENDIX G – CULTURAL RESOURCES SURVEY
Summary Report:
A Phase I Remote-Sensing Archaeological Survey of
A Proposed Borrow Site off Avon, Dare County, North Carolina
[Detail of 1904 U.S. Coast & Geodetic Survey Chart No.: 145 (Courtesy of NOAA Historical Map & Chart Collection)]
Prepared for:
US Army Corps of Engineers-Wilmington District
Washington NC Field Office
2407 West 5th Street
Washington, NC 27889
and
National Park Service – US Department of Interior
Cape Hatteras National Seashore
1401 National Park Drive
Manteo, NC 27954
Prepared by:
Tidewater Atlantic Research, Inc.
PO Box 2494, Washington, NC 27889
30 July 2021
Summary Report Entitled:
A Phase I Remote-Sensing Archaeological Survey of
A Proposed Borrow Site off Avon, Dare County, North Carolina
Prepared for:
US Army Corps of Engineers-Wilmington District
Washington NC Field Office
2407 West 5th Street
Washington, NC 27889
and
National Park Service – US Department of Interior
Cape Hatteras National Seashore
1401 National Park Drive
Manteo, NC 27954
Submitted by:
Gordon P. Watts, Jr., Ph.D, RPA
Principal Investigator
Tidewater Atlantic Research, Inc.
P. O. Box 2494
Washington, North Carolina 27889
Submittal Date:
30 July 2021
i
Abstract
Coastal Science and Engineering (CSE) of Columbia, South Carolina is working with the Dare County
Board of Commissioners to identify and permit a sand source for the beach restoration project on Hatteras
Island where erosion threatens Highway 12. The proposed project is intended to widen the oceanfront beach
and provide an erosion buffer to reduce chronic highway damage and maintain county infrastructure. The
primary borrow source has been identified as a shoal located approximately 2.6 miles offshore of the Village
of Avon. In order to determine any effect on potentially significant submerged cultural resources, C SE
contracted with Tidewater Atlantic Research (TAR) of Washington, North Carolina to conduct a submerged
cultural resource remote-sensing survey of the proposed borrow site. Due to long-standing adverse weather,
remote-sensing survey operations off Avon were not initiated until 26 May 2021 and were not completed
until 24 July 2021. Analysis of the magnetic and acoustic data from the Avon borrow site identified a total
of seven magnetic anomalies. One of those anomalies was identified outside the buffer area and three were
identified inside the 200-foot buffer area. The remaining three anomalies were located within the proposed
borrow site. The anomalies inside the borrow site and the anomalies inside the buffer represent very small
ferrous objects. None of the magnetic signatures are suggestive of complex vessel remains and none are
recommended for avoidance. Analysis of the acoustic data identified no evidence of targets in the Avon
survey area. According to the remote-sensing data, no potentially significant submerged cultural resources
will be impacted by dredging in the proposed Avon borrow area or the adjacent buffer.
This is the summary report of the archeological survey. A detailed report will be available and submitted
to the North Carolina State Historic Preservation Office for review and comment. The results, finding, and
no avoidance recommendations in the full report are expected to be consistent with this summary report.
ii
Table of Contents
Page
Abstract .......................................................................................................................................................... i
List of Figures .............................................................................................................................................. iii
List of Tables ............................................................................................................................................... iv
Introduction ................................................................................................................................................... 1
Project Personnel .......................................................................................................................................... 1
Project Location ............................................................................................................................................ 2
Magnetic Data Analysis ................................................................................................................................ 4
Acoustic Data Analysis ................................................................................................................................. 6
Conclusions ................................................................................................................................................... 7
Unexpected Discovery Protocol.................................................................................................................... 7
Attachment A: Magnetic Anomaly Table ..................................................................................................... 8
iii
List of Figures
Page
Figure 1. Avon project location on NOAA Chart #11555-1. ........................................................................ 2
Figure 2. Avon borrow site and 200 foot buffer with buffer points. ............................................................. 3
Figure 3. Avon survey tracklines. ................................................................................................................. 4
Figure 4. Avon survey area magnetic anomalies. ......................................................................................... 5
Figure 5. Avon survey area sonar coverage mosaic. ..................................................................................... 6
iv
List of Tables
Page
Table 1. NCSP coordinates for the Avon survey area. ................................................................................. 3
Introduction
Coastal Science and Engineering (CSE) of Columbia, South Carolina is working with the Dare County
Board of Commissioners to identify and permit a sand source for the beach restoration project on Hatteras
Island where erosion threatens Highway12. The primary borrow source has been i dentified as a shoal
located approximately 2.6 miles offshore of the Village of Avon shoreline. In order to determine any effect
on potentially significant submerged cultural resources, CSE contracted with Tidewater Atlantic Research
(TAR) of Washington, North Carolina to conduct a submerged cultural resource remote-sensing survey of
the proposed borrow site.
The remote-sensing investigation conducted by TAR was designed to provide accurate and reliable
identification, assessment and documentation of submerged cultural resources in the study area. The
assessment methodology was developed to comply with the criteria of the National Historic Preservation
Act of 1966 (Public Law 89-665), the National Environmental Policy Act of 1969 (Public Law 11-190),
Executive Order 11593, the Advisory Council on Historic Preservation Procedures for the protection of
historic and cultural properties (36 CFR Part 800), the updated guidelines described in 36 CFR 64 and 36
CFR 66, Archaeological Resource Protection Act (16 USC 470), “Abandoned Shipwreck Law” (North
Carolina General Statute [NCGS] 121, article 3) and the North Carolina Archaeological Resources
Protection Act (NCGS 70, article 2). The results of the investigation were designed to furnish CSE with the
archaeological data required to comply with State and Federal submerged cultural resource legislation and
regulations.
Field investigations focused on a remote-sensing survey carried out with magnetic and acoustic remote
sensing equipment. Due to long-standing adverse weather, remote-sensing survey operations off Hatteras
were not initiated until 26 May and were not completed until 24 July 2021. To reliably identify anomalies
associated with submerged cultural resources, survey equipment included both magnetic and acoustic
remote sensing employing a magnetometer, sidescan sonar, and sub-bottom profiler. Navigation and data
collection was accomplished using differential global positioning and computer survey software.
Analysis of the magnetic and acoustic data from the Avon borrow site identified a total of seven magnetic
anomalies. One of those anomalies was located outside the buffer area and three were identified inside the
200-foot buffer. The remaining three anomalies were located within the proposed borrow site. All of the
anomalies identified during the survey represent very small ferrous objects. None of the magnetic signatures
are suggestive of complex vessel remains and none are recommended for avoidance. Analysis of the
acoustic data identified no evidence of sonar targets in the Avon survey area.
According to the remote-sensing data, no potentially significant submerged cultural resources will be
impacted by dredging in the proposed Avon borrow area or in the adjacent buffer. Consequently, no
additional investigation is recommended.
Project Personnel
TAR project field personnel included principal archaeological investigator Gordon P. Watts, Jr. and
archaeologist/remote-sensing operators Ralph Wilbanks and John Morris. Senior historian Robin Arnold
carried out the historical and literature research. Dr. Watts analyzed the remote-sensing data. Dr. Watts and
Ms. Arnold prepared this report.
2
Project Location
The survey site under investigation lies in the Atlantic Ocean approximately 2.6 miles offshore of the
Village of Avon in Dare County, North Carolina (Figure 1).
Figure 1. Avon project location on NOAA Chart #11555-1.
The proposed borrow area, including a 200-foot buffer, is a polygon 7,620 feet in northeast to southwest
length and a maximum of 2,380 feet in southeast to northwest width. The buffered survey area encompasses
a total of 350 acres and .55 square statute miles. North Carolina State Plane (NCSP), NAD 83, U.S. Survey
Foot geographical coordinates for the survey area are shown in Figure 2 and Table 1.
3
Figure 2. Avon borrow site and 200 foot buffer with buffer points.
Table 1. NCSP coordinates for the Avon survey area.
To ensure sufficient data would be available to locate any potentially significant magnetic anomalies and
sonar targets in the survey area, remote-sensing data were collected along parallel lanes spaced on 100-foot
intervals (Figure 3). The area surveyed also included a 200-foot buffer zone so that those anomalies and/or
targets located along the periphery of the borrow area could be identified and the impact from dredging
assessed.
4
Figure 3. Avon survey tracklines.
Magnetic Data Analysis
Analysis of the magnetic data from the Avon survey site identified a total of seven magnetic anomalies
(Figure 4; Attachment A). One of those anomalies was identified outside of the buffer area. Three were
located inside the buffer area and the remaining three were identified inside the area to be dredged. All
seven anomalies represent small ferrous objects and none appear to represent a potentially significant
submerged cultural resource. None are recommended for avoidance and none of the magnetic signatures
are suggestive of complex vessel remains.
5
Figure 4. Avon survey area magnetic anomalies.
6
Acoustic Data Analysis
Analysis of the acoustic data identified no evidence of targets in the Avon survey area (Figure 5).
Figure 5. Avon survey area sonar coverage mosaic.
7
Conclusions
The coastal waters off the Outer Banks of North Carolina have one of the highest documented
concentrations of shipwrecks in the western Atlantic. The moniker “Graveyard of the Atlantic” is well
earned. Hundreds of vessels have been reported lost off the Outer Banks and especially near Cape Hatteras.
Weather, currents, natural magnetic anomalies, and fluctuating shoals make navigation along coastal Dare
County hazardous in the present day. For over 500 years, human error and warfare compounded dangers
associated with the natural environment.
Although the project survey site lies within an area of high sensitivity for historic shipwrecks, no wreck
remains have been included in the North Carolina Underwater Branch (UAB) site files (Nathan Henry to
Robin Arnold, elec. comm., 24 July 2021). The primary reason is no doubt a direct function of the fact that
a limited number of systematic remote-sensing surveys have been carried out in the Cape Hatteras vicinity.
Data generated by this survey identified only seven small magnetic anomalies in the Avon survey area.
None of those signatures, are suggestive of complex vessel remains. Consequently, no additional
investigation is recommended in conjunction with the project as designed.
Unexpected Discovery Protocol
Data generated by this survey does not identify any historical shipwrecks or other submerged cultural
resources. However, in the event that any project activities expose potential prehistoric or historic cultural
material, the dredge company under contract to Dare County should immediately shift operations away
from the site and notify the respective Point of Contact for CSE (Columbia SC), the Dare County
Commissioners (Manteo NC), the North Carolina SHPO (Raleigh NC), and UAB (Kure Beach NC).
Notification should address the exact location, where possible, the nature of material exposed by project
activities, and options for immediate archaeological inspection and assessment of the site or sites.
Attachment A: Magnetic Anomaly Table