Marie K. Bartlett 20230815 1.0 vector digital data data release doi:10.5066/P9LLAZYE 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/P9LLAZYE https://www.sciencebase.gov/catalog/item/6480c408d34eac007b57b7c1 Marie K. Bartlett Amy S. Farris Kathryn M. Weber 2023 1.0 vector digital data data release doi:10.5066/P9LLAZYE Reston, VA U.S. Geological Survey Bartlett, M.K., Farris, A.S., and Weber, K.M., 2023, USGS National Shoreline Change — A GIS compilation of new lidar-derived shorelines (2010, 2017, and 2018) and associated shoreline change data for coastal South Carolina: U.S. Geological Survey data release, https://doi.org/P9LLAZYE. https://doi.org/10.5066/P9LLAZYE https://www.sciencebase.gov/catalog/item/6480a887d34eac007b5793e9 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 two new mean high water (MHW) shorelines extracted from lidar data collected in 2010 and 2017-2018. Previously published historical shorelines for South Carolina (Kratzmann and others, 2017) were combined with the new lidar shorelines to calculate long-term (up to 166 years) and short-term (up to 18 years) rates of change. 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 which are created by the Digital Shoreline Analysis System (DSAS) version 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, 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. 2000 2018 ground condition at the time of shoreline source data Complete None planned -80.876393 -78.554070 32.081482 33.848903 ISO 19115 Topic Category environment oceans geoscientificInformation None Shoreline Change Digital Shoreline Analysis System DSAS U.S. Geological Survey USGS Woods Hole Coastal and Marine Science Center WHCMSC North America Southeast Atlantic short-term shoreline change erosion accretion USGS Thesaurus coastal processes geospatial datasets erosion shoreline accretion USGS Metadata Identifier USGS:6480c408d34eac007b57b7c1 None Atlantic Coast South Carolina 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/6480c408d34eac007b57b7c1?name=SC_intersects_ST_browse.JPG Map view of dataset JPEG Microsoft Windows 10 Esri ArcGIS 10.7.1 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://doi.org/10.5066/P9VW42I0 https://code.usgs.gov/cch/dsas/ https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-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://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Emily A. Himmelstoss Meredith G. Kraztmann E. Robert Thieler 2012 vector digital data Open-File Report 2017-1015 Reston, VA U.S. Geological Survey https://doi.org/10.3133/ofr20211091 https://pubs.er.usgs.gov/publication/ofr20211091 Meredith G. Kratzmann Emily A. Himmelstoss E. Robert Thieler 2017 vector digital data data release 2017 Reston, VA U.S. Geological Survey https://doi.org/10.5066/F74X55X7 https://www.sciencebase.gov/catalog/item/58055f50e4b0824b2d1c1ee7 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. TThese 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, such as those crossing man-made coastal structures, were included in the desired long-term (LT) or short-term (ST) shoreline change analysis. It is possible that a small (centimeter-scale) offset may occur when projecting from outside of the spatial reference system used for analysis (UTM Zone 17N WGS84). This is an ArcGIS projection issue; rate data are unaffected. This dataset contains the intersects automatically generated by the DSAS software application that were used to calculate shoreline change rates for the region. 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 (see larger work citation, SC_shoreline_2010 and SC_shoreline_2017_2018). See Kratzmann and others, 2017, cross-referenced in this metadata file, for uncertainties associated with the historical (2000) shoreline position. MHW shorelines (2000-2018), the short-term subset of shorelines used for ST rate calculations, were exported from SC_shorelines and renamed SC_shorelines_ST. Short-term transect features were generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer = SC_baseline, baseline group field = NULL, shoreline layer = SC_shorelines_ST, transect spacing = 50 meters, search distance = 200 meters, land direction = right, shoreline intersection = seaward, File produced = SC_transects_ST. Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in the editor toolbar, 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://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas 2022 Short-term rate calculations were performed without a proxy-datum bias correction which was unnecessary, since only datum-based MHW shorelines (2000-2018) were used. Parameters Used: shoreline layer= SC_shorelines_ST, shoreline date field = Date_, shoreline uncertainty field name = Uncy, the default accuracy = 5.1 meters, shoreline intersection = seaward, stats calculations = [LRR], [EPR], shoreline threshold = 2, confidence interval = 90%. Files produced = SC_trans_ST_rates_20230802_102308, SC_trans_ST_intersect_20230802_102308. 20221208 The intersect feature classes were exported to a shapefile in ArcMap v10.7.1 by right-clicking the transect layer > data > export data. Coordinate system: UTM Zone 17N (WGS84). 2023 Vector Entity point 15170 Universal Transverse Mercator 17 0.9996 -81.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters WGS_1984 WGS_84 6378137.0 298.257223563 SC_intersects_ST 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 short-term rates. Because only modern, MHW lidar shorelines were used to calculate short-term rates, the proxy-datum bias calculation does not apply. 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 2 5664 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 26 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) shoreline movement. USGS -1161.658 1163.577 meters IntersectX The easting or X-coordinate location of the intersect point in WGS84 UTM17N. USGS 511665.01 726302.542 IntersectY The northing or Y-coordinate location of the intersect point in WGS84 UTM17N. USGS 3549474.221 3748090.691 Uncertaint The uncertainty of the shoreline intersect point as defined by the positional uncertainty value of the shoreline. USGS 0.7 18.617 The entity and attribute information provided here describes the tabular data associated with the intersects needed to calculate short-term (approximately 18 years) shoreline change rates. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units and were based on the UTM zone 17N WGS 84 projection. 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 South Carolina shorelines and transect data (SC_intersects_ST.shp and other shapefile components), browse graphic (SC_intersects_ST_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. 0.21 https://doi.org/10.5066/P9LLAZYE https://www.sciencebase.gov/catalog/file/get/6480c408d34eac007b57b7c1 https://www.sciencebase.gov/catalog/item/6480c408d34eac007b57b7c1 The first link is to the USGS publication page, the second link downloads all the data on the landing page, and the third link is to the dataset landing page. None. 20230815 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. FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998