Marie K. Bartlett 20230526 1.0 vector digital data data release doi:10.5066/P9DHOFXU Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P9DHOFXU https://www.sciencebase.gov/catalog/item/641c6d69d34e807d39b643db Marie K. Bartlett Rachel E. Henderson Amy S. Farris 2023 1.0 vector digital data data release doi:10.5066/P9DHOFXU Reston, VA U.S. Geological Survey Bartlett, M.K., Henderson R.E., and Farris, A.S., 2023, USGS National Shoreline Change — A GIS compilation of vector shorelines and associated shoreline change data for coastal Virginia from the 1840s to 2010s: U.S. Geological Survey data release, https://doi.org/10.5066/P9DHOFXU. : https://doi.org/10.5066/P9DHOFXU https://www.sciencebase.gov/catalog/item/641b186fd34e4c337f0c1de3 The U.S. Geological Survey (USGS) has compiled national shoreline data for more than 20 years to document coastal change and serve the needs of research, management, and the public. Maintaining a record of historical shoreline positions is an effective method to monitor national shoreline evolution over time, enabling scientists to identify areas most susceptible to erosion or accretion. These data can help coastal managers and planners understand which areas of the coast are vulnerable to change. This data release includes a compilation of previously published historical shoreline positions for Virginia spanning 148 years (1849-1997), and two new mean high water (MHW) shorelines extracted from lidar data collected in 2010 and 2017. These data provide a standardized shoreline database for the state. This release includes both long-term (up to 168 years) and short term (~20 years) rates. Files associated with the long-term and short-term rates are appended with "LT" and "ST", respectively. A proxy-datum bias reference line that accounts for the positional difference in a proxy shoreline (e.g. High Water Line (HWL) shoreline) and a datum shoreline (e.g. MHW shoreline) is also included in this release. This dataset consists of point data created by the Digital Shoreline Analysis System (DSAS) v5.1 at the intersection of shoreline and transect locations. Measurement transects are cast by DSAS from the baseline to intersect shoreline vectors, and the intersect data provide location and time information used to calculate rates of change. These point data contain identification information related to the DSAS transect (TransOrder) as well as the shoreline (ShorelineID and Uncertainty) and proxy-datum bias data (if applicable). They can be used to visually display which shorelines were used in the rate calculations and capture details on the shoreline represented by the intersection. The distances between the reference baseline and each shoreline intersection along a transect are used by the DSAS software to compute the shoreline change metrics. 1849 2017 ground condition at the time of shoreline source data Complete None planned -76.0664 -75.2373 38.0273 36.5490 ISO 19115 Topic Category environment oceans geoscientificInformation None Baseline Shoreline Shoreline Change Digital Shoreline Analysis System DSAS U.S. Geological Survey USGS Woods Hole Coastal and Marine Science Center WHCMSC North America Mid-Atlantic erosion accretion long-term change short-term change USGS Thesaurus coastal processes geospatial datasets erosion shoreline accretion USGS Metadata Identifier USGS:641c6d69d34e807d39b643db None Atlantic Coast Virginia United States None. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. These data are not to be used for navigation. Marie K. Bartlett U.S. Geological Survey Geologist mailing

384 Woods Hole Rd

Woods Hole MA 02543 508-457-8700 x2306 mbartlett@usgs.gov https://www.sciencebase.gov/catalog/file/get/641c6d69d34e807d39b643db?name=VA_intersects_LT_browse.JPG Map view of dataset JPEG Microsoft Windows 10 Esri ArcGIS 10.7.1 Cheryl J. Hapke Emily A. Himmelstoss Meredith G. Kraztmann Jeffrey H. List E. Robert Thieler 20120423 vector digital data Open-File Report 2010-1118 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/of/2010/1118/ Emily A. Himmelstoss Amy S. Farris Rachel E. Henderson Meredith G. Kratzmann Ayhan Ergul Ouya Zhang Jessica L. Zichichi E. Robert Thieler 2021 publication software release version 5.1 Reston, VA U.S. Geological Survey Use the first two links to access the software. The third link directs to the DSAS project page. Current version of software at time of use was 5.1. https://code.usgs.gov/cch/dsas/ https://doi.org/10.5066/P9VW42I0 https://woodshole.er.usgs.gov/project-pages/DSAS/ Emily A. Himmelstoss Rachel E. Henderson Meredith G. Kratzmann Amy S. Farris 20211019 publication Open-File Report 2021-1091 Reston, VA U.S. Geological Survey Refer to the DSAS user guide for more information about attribute requirements, accuracy reports, and feature creation. https://doi.org/10.3133/ofr20211091 https://woodshole.er.usgs.gov/project-pages/DSAS/ Peter Ruggiero Jeffrey H. List 200909 publication Journal of Coastal Research vol. 255 n/a Coastal Education and Research Foundation ppg. 1069-1081 https://doi.org/10.2112/08-1051.1 The attributes of this dataset are based on the field requirements of the Digital Shoreline Analysis System and were automatically generated by the software during the generation of the intersects layer. These data were generated using DSAS v5.1, an automated software program, which does not perform checks for fidelity of the input features. Following generation of the rates and intersects by the DSAS software, a visual inspection of the intersects was performed in map view to determine that no unwanted measurements were included in the desired long-term (LT) or short-term (ST) shoreline change analysis. This dataset contains the transects automatically generated by the DSAS software application that were used to calculate shoreline change rates for the region. Additional transects may have been generated but did not intersect the minimum requirement of three shorelines. Shoreline change rates data are provided where there are available shorelines to compute change metrics. Though the full database of shorelines was utilized (1849-2017), gaps in shorelines or lack of lidar data in certain areas may mean that not all transects will incorporate every shoreline date in the rate calculations. The intersection points represent the location where transects cast by the Digital Shoreline Analysis System (DSAS) software crosses a historical shoreline position. The positional uncertainties associated with the shoreline and intersection points are captured in the shoreline attribute table. A polyline, midshore baseline was constructed using standard feature creation tools in Esri's ArcMap v10.7.1. The baseline was positioned to follow the overall orientation of the shorelines alongshore (see larger work citation, VA_baseline.shp, VA_shorelines.shp). This was done so that the transects, which are generated by the DSAS software and extend from the baseline, would intersect roughly perpendicular to the general trend of the shorelines. The baseline was constructed in UTM Zone 18N (WGS 84) coordinate system. This process step and all subsequent process steps were performed by the same person - Marie K. Bartlett 2022 Marie K. Bartlett U.S. Geological Survey Geologist mailing and physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x 2306 mbartlett@usgs.gov Transect features were generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer = VA_baseline, baseline group field = NULL, shoreline layer = VA_shorelines, transect spacing = 50 meters, search distance = 1000 meters, land direction = right, shoreline intersection=seaward, File produced = VA_trans_LT. Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.7.1. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://woodshole.er.usgs.gov/project-pages/DSAS/. 2022 Shoreline intersects and rate calculations were performed for long-term (LT) rates with and without bias. Parameters Used: shoreline layer = VA_shorelines, shoreline date field = Date_, shoreline uncertainty field name = Uncy_, the default accuracy = 5.1 meters, shoreline intersection=seaward, stats calculations = [LRR], shoreline threshold = 3, confidence interval = 90%. Files produced = VA_trans_LT_rates_20230321_135326, VA_trans_LT_intersect_20230321_135326. The shoreline database contains both MHW and HWL shorelines thus a proxy-datum bias (PDB), stored as a line feature class appended to the reference baseline, is applied during rate calculation. For more information about the origin of the PDB see Ruggiero and List (2009). Rate statistics are presented with and without the PDB applied, denoted in the attribute field with “NB_” or “No bias”. The bias uncertainty values and location data are stored within the bias feature attribute table and the intersects attribute table. 2023 The intersect feature classes were exported to shapefiles in ArcMap v10.7.1 by right-clicking the transect layer > data > export data. Coordinate System: UTM Zone 18N (WGS84) 2023 Fixed the structure of the first DOI link (20240709). 20240709 U.S. Geological Survey VeeAnn A. Cross Marine Geologist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543-1598 USA (508) 548-8700 x2251 (508) 457-2310 vatnipp@usgs.gov Vector Entity point 23552 Universal Transverse Mercator 18 0.9996 -75.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters WGS_1984 WGS_84 6378137.0 298.257223563 VA_intersects_LT.shp Attribute Table The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shoreline position and contain the data necessary for DSAS to compute long-term rates, with and without the proxy-datum bias. U.S. Geological Survey (USGS) FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Feature geometry. Intersects are point shapefiles. TransOrder Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. USGS 1 3672 BaselineID Values in this field correlate to the baseline attribute field ID and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. Baseline segments assigned an ID = 0 are ignored by DSAS and no transects will be cast along those line segments. USGS 1 14 ShorelineI Date of shoreline position; date of survey as determined from shoreline layer. USGS Date of the shoreline in mm/dd/yyyy Distance The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect. Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. USGS -996.629 2178.12 meters IntersectX The easting or X-coordinate location of the intersect point in WGS84 UTM18N. USGS 406400.008 478764.615 IntersectY The northing or Y-coordinate location of the intersect point in WGS84 UTM18N. USGS 4045351.867 4208872.394 Uncertaint The uncertainty of the shoreline intersect point as defined by the positional-uncertainty value (Uncy_) of the shoreline (ShorelineID). USGS 1.301 16.327 Bias_Dista The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect with the proxy-datum bias applied. May be positive or negative depending on the orientation of the baseline. USGS -996.629 2193.578 BIAS The estimated unidirectional horizontal offset between the MHW elevation of the lidar data and the HWL shoreline position. USGS 0.001 21.737822 BIAS_X The X-coordinate location of the intersect point with the bias applied. USGS 406400.008 478772.051 BIAS_Y The Y-coordinate location of the intersect point with the bias applied. USGS 4045353.489 4208869.688 Bias_Uncer This is an estimate of the uncertainty of the bias corrected shoreline. It is the shoreline uncertainty and the bias uncertainty added in quadrature. USGS 1.301 16.327 The entity and attribute information provided here describes the tabular data associated with the intersects needed to calculate long-term (greater than 50 years, and typically closer to 100 years). Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units and were based on the UTM zone 18N WGS 84 projection. This region has two shapefiles describing intersects, long-term and short-term (see the larger work citation). U.S. Geological Survey U.S. Geological Survey USGS ScienceBase mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov The dataset contains the point data representing the intersection of Virginia shorelines and transect data (VA_intersects_LT.shp and other shapefile components), browse graphic (VA_intersects_LT_browse.JPG), and the FGDC CSDGM metadata in XML format. Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), and have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Shapefile ArcGIS 10.7.1 Esri Point Shapefile These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, and .shx) are a collection of files with a common filename prefix and must be downloaded and stored in the same directory. Together they are the components of the shapefile. Additional files of the same name included are FGDC CSDGM-compliant metadata in XML format. 1.4 https://www.sciencebase.gov/catalog/item/641c6d69d34e807d39b643db None. 20240709 Marie K. Bartlett U.S. Geological Survey mailing and physical

384 Woods Hole Rd

Woods Hole MA 02543-1598 USA 508-548-8700 x2306 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. The contact instructions were updated on 20240319. FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998