Meredith G. Kratzmann 20260622 1.0 vector digital data data release DOI:10.5066/P1JE2KSO 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/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2b046b66b0195694c11e9 Meredith G. Kratzmann Amy S. Farris Kathryn M. Weber 2026 1.0 vector digital data data release DOI:10.5066/P1JE2KSO Reston, VA U.S. Geological Survey suggested citation: Kratzmann, M.G., Farris, A.S., and Weber, K.M., 2026, National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to the 2020s for the coast of Alabama: U.S. Geological Survey data release, https://doi.org/10.5066/P1JE2KSO. https://doi.org/10.5066/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2a7d5b66b0195694c1197 The U.S. Geological Survey (USGS) maintains shoreline positions for the United States coasts from various historical sources, such as aerial photographs or topographic surveys, and contemporary sources, such as lidar-point clouds and digital elevation models. Shorelines are compiled in a Geographic Information System (GIS) and analyzed in the USGS Digital Shoreline Analysis System (DSAS) software to calculate rates of change. Keeping a record of historical shoreline positions is an effective method to monitor change over time, enabling scientists to identify areas most susceptible to erosion or accretion. These data can help coastal managers understand which areas of the coast are vulnerable to change. The shoreline positions and shoreline change rates provide actionable information to homeowners, coastal communities, and managers of public and private properties to improve resiliency for coastal hazards. Shoreline positions were compiled for Alabama from the mid-1800s through the 2020s and were used to calculate long-term (century-scale) shoreline change rates using the Digital Shoreline Analysis System (DSAS) software developed by the U.S. Geological Survey. A reference baseline was used as the originating point for the orthogonal transects cast by the DSAS software. The transects intersect each shoreline, establishing measurement points which provide location and time information used to calculate rates of change. Rate calculations were computed using DSAS version 6.1. 2026 publication date Complete None planned -88.335542 -87.518227 30.291621 30.218328 ISO 19115 Topic Category oceans geoscientificInformation environment None Shoreline change rate Long-term shoreline change rate Linear Regression Rate LRR End point rate EPR Proxy-Datum Bias PDB Transect Digital Shoreline Analysis System DSAS U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Woods Hole Coastal and Marine Science Center WHCMSC USGS Thesaurus geospatial datasets coastal processes erosion shoreline accretion USGS Metadata Identifier USGS:69e2b046b66b0195694c11e9 GNIS State of Alabama Dauphin Island Fort Morgan Alabama Gulf Shores None Gulf Coast Bon Secour National Wildlife Refuge United States of America North America No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. These data were automatically generated using the DSAS v6.1 software application. 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. U.S. Geological Survey Meredith G. Kratzmann mailing and physical

384 Woods Hole Road

Woods Hole MA 02543-1598 USA 508-548-8700 508-457-2310 mkratzmann@contractor.usgs.gov https://www.sciencebase.gov/catalog/file/get/69e2b046b66b0195694c11e9?name=AL_rates_LT.png&allowOpen=true Map view of data. Green lines indicate the extent of the long-term (century-scale) shoreline change rates for Alabama. PNG Microsoft Windows 11 Enterprise; Esri ArcGIS Pro 3.5.5 Rachel E. Henderson Amy S. Farris Meredith G. Kratzmann Marie K. Bartlett Ayhan Ergul John McAndrews Raison Cibaj Jessica L. Zichichi Emily A. Himmelstoss E. Robert Thieler 2026 publication software release version 6.1.177 Reston, VA U.S. Geological Survey Use the first link to access the publication page. The second link is to the current version of DSAS (v6.1). The third link directs to the DSAS project page. https://doi.org/10.5066/P1NHMJNC https://code.usgs.gov/cch/dsas https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas 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 transect layer or during the calculation of shoreline change rates. These data were generated using DSAS v6.1. The transects automatically generated by the software were visually inspected along with the shoreline data prior to rate calculations. Sometimes transect positions were manually edited to better represent an orthogonal position to the general trend of the shorelines. This dataset contains the transects automatically generated by the DSAS software application that were used to calculate long-term (century-scale) shoreline change rates for the region. Additional transects may have been generated but did not meet the required number of shorelines or time period requirements. The uncertainty of the linear regression rate is estimated by the elements lr2, lse and lci90. See the attribute definition of each for more information. Meredith G. Kratzmann 2026 1.0 vector digital data data release DOI:10.5066/P1JE2KSO Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey The first link is to the larger work, the second link is to the baseline dataset. https://doi.org/10.5066/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2afc2b66b0195694c11e3 digital data 2026 publication date AL_baseline Baseline segments for Alabama (part of this same data release https://doi.org/10.5066/P1JE2KSO) are used by DSAS to cast measurement transects. Meredith G. Kratzmann Amy S. Farris 2026 1.0 vector digital data data release DOI:10.5066/P1JE2KSO Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey The first link is to the larger work, the second link is to the shorelines dataset. https://doi.org/10.5066/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2b013b66b0195694c11e7 digital data 2026 ground condition AL_shorelines Shoreline data for Alabama (part of this same data release https://doi.org/10.5066/P1JE2KSO). Meredith G. Kratzmann Amy S. Farris 2026 1.0 vector digital data data release DOI:10.5066/P1JE2KSO Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey The first link is to the larger work, the second link is to the bias feature dataset. https://doi.org/10.5066/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2b0f0b66b0195694c11f1 digital data 2026 publication date AL_bias Bias feature for Alabama (part of this same data release https://doi.org/10.5066/P1JE2KSO) used by DSAS to calculate rates that account for the offset between proxy-based HWL/WDL and datum-based MHW shorelines. Overview of the workflow used to calculate shoreline change rates and intersection points as part of the shoreline change analysis using DSAS v6.1: 1) Transects were generated at 50-meter spacing using a manually created baseline and shorelines compiled for Alabama (see source citations in the shorelines metadata file); 2) Manual edits to transects performed; 3) Transects and shorelines were used to generate intersection points and calculate rates of change. The following process steps describe these actions. For more details on the DSAS software, please visit: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas This and the following process steps were performed by the same person: Meredith Kratzmann. 2026 U.S. Geological Survey Meredith Kratzmann Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543 508-548-8700 508-457-2310 mkratzmann@contractor.usgs.gov DSAS v6.1 was used to create transect features using the baseline and shorelines shapefiles for Alabama. Input parameters: shoreline layer = Shorelines_AL, baseline layer= Baseline_AL, transect spacing= 50 meters, transect length= 1500 meters, smoothing distance= 2000 meters, clip transects to shoreline extent= unchecked. File produced= AL_transects_ALL. Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcGIS Pro 3.5.5. Edited transect shapefile was renamed= AL_transects. Baseline_AL Shorelines_AL 2026 AL_transects To calculate long-term (LT) shoreline change rates, Alabama shorelines from 1849 to 2022 were utilized with the DSAS-generated transects to create shoreline intersect points and perform rate calculations. Input parameters: shoreline layer= Shorelines_AL, transects layer= AL_transects, bias feature= AL_bias, date range= full range (all shorelines), shoreline intersection threshold= 2, calculate= EPR (end point rate), LRR (linear regression rate), NSM (net shoreline movement), SCE (shoreline change envelope), confidence interval=90%, create DSAS summary report= checked. Shapefiles produced= al_transects_intersect_20260114_141331, al_transects_rates_20260114_141331. Shorelines_AL AL_transects AL_bias 2026 al_transects_intersect_20260114_141331 al_transects_rates_20260114_141331 The rates were exported from DSAS in shapefile format using the Export Data tool and renamed= AL_rates_LT. al_transects_rates_20260114_141331 2026 AL_rates_LT The rates shapefile was projected in ArcGIS Pro v3.5.5 > Geoprocessing > Data Management Tools > Projections and Transformations > Project. Parameters: Input Coordinate System - NAD_1983_2011_UTM_Zone_16N; Output Coordinate System - GCS_WGS_1984; transformation = WGS_1984_(ITRF08)_To_NAD_1983_2011. 2026 Vector String 1510 0.0000001 0.0000001 Decimal degrees WGS_1984 WGS_1984 6378137.0 298.257224 AL_rates_LT.shp Transects and shorelines were used to generate intersection points and shoreline change rate transects. These attributes are for long-term rates in Alabama. U.S. Geological Survey FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Feature type. baselineid Unique identification number of the baseline segment starting at 1. If baselineid= 0 no transects will be generated. Used by DSAS to determine transect ordering alongshore if multiple baseline segments exist. U.S. Geological Survey 1 4 transorder Number assigned by DSAS based on the ordering of transects from baseline start to baseline end. U.S. Geological Survey 37 1819 length Length of feature in meter units. Esri 489.76 1593.94 meters tcd The total cumulative distance (TCD) is the measure in meters alongshore from the start of the baseline segment with an identifier of 1 and measured sequentially alongshore to the end of the final baseline segment. U.S. Geological Survey 1800 90900 meters shrcount Number of shorelines used to compute shoreline change metrics. U.S. Geological Survey 5 32 lrr A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect, using shoreline position plotted against shoreline date. Any shoreline points that are referenced to HWL were adjusted by the proxy-datum bias distance (meters) along the transect to correct for the offset between proxy-based HWL and datum-based MHW shorelines. The best-fit regression line is placed so that the sum of the squared residuals (determined by squaring the offset distance of each data point from the regression line and adding the squared residuals together) is minimized. The linear regression rate is the slope of the line. The rate is reported in meters per year with positive values indicating accretion (shoreline advance, seaward movement) and negative values indicating erosion (shoreline retreat, landward movement). U.S. Geological Survey -4.15 10.05 meters per year lr2 The R-squared statistic, or coefficient of determination, is the proportion of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). U.S. Geological Survey 0 0.96 lci90 The standard error of the slope with confidence interval describes the uncertainty of the reported rate. The LRR rates are determined by a best-fit regression line for the shoreline data at each transect. The slope of this line is the reported rate of change (in meters/year). The confidence interval (LCI) is calculated by multiplying the standard error of the slope by the two-tailed test statistic at the user-specified 90 percent confidence. This value is often reported in conjunction with the slope to describe the confidence of the reported rate. For example: LRR = 1.2 LCI90 = 0.7 could be reported as a rate of 1.2 (+/-) 0.7 meters/year. U.S. Geological Survey 0.06 3.15 meters lse This quantity is the standard error of the regression, also known as the standard error of the estimate. To calculate it, the distance between each data point and the regression line is calculated. These distances are squared then summed. The sum is divided by the number of data points minus two. The square root is taken of the result. U.S. Geological Survey 6.26 404.83 meters epr The end point rate is calculated by dividing the distance of shoreline movement by the time elapsed between two shorelines, the oldest and most recent only. The rate is reported in meters per year with positive values indicating accretion (shoreline advance, seaward movement) and negative values indicating erosion (shoreline retreat, landward movement). U.S. Geological Survey -3.92 12.50 meters per year eprunc Describes the uncertainty of the reported end point rate (EPR) in meters. The shoreline uncertainties for the two positions used in the end point calculation are each squared then added together (summation of squares). The square root of the summation of squares is divided by the number of years between the two shorelines. This result is reported as the confidence of the end point rate calculation (eprunc). U.S. Geological Survey 0.06 0.36 meters nsm The net shoreline movement (NSM) is the distance in meters between the oldest and the most recent shorelines. U.S. Geological Survey -590.94 1067.54 meters sce The shoreline change envelope (SCE) value represents the greatest distance that covers all the shorelines intersected by a transect. The value for SCE is always positive, as the metric is based on magnitude, not direction. U.S. Geological Survey 33.27 1171.93 meters nb_lrr A linear regression rate-of-change statistic as described in the attribute lrr but without the proxy-datum bias correction applied (nb= no bias applied). U.S. Geological Survey -4.12 10.09 meters per year nb_lr2 The R-squared statistic, or coefficient of determination, as described in the attribute lr2 but for nb_ (no bias applied) rates. U.S. Geological Survey 0 0.96 nb_lci90 The 90 percent confidence interval as described in the attribute lci90 but for nb_ (no bias applied) rates. U.S. Geological Survey 0.07 3.15 meters nb_lse The standard error as described in the attribute LSE but for nb_ (no bias applied) rates. U.S. Geological Survey 6.84 404.75 meters nb_epr The end point rate as described in the attribute epr but for nb_ (no bias applied) rates. U.S. Geological Survey -3.92 12.57 meters per year nb_eprunc The uncertainty of the end point rate (EPR) as described in the attribute epr but for nb_ (no bias applied) rates. U.S. Geological Survey 0.06 0.36 meters nb_nsm The net shoreline movement (NSM) is the distance in meters between the oldest and the most recent shorelines (no bias applied). U.S. Geological Survey -586.45 1072.28 meters nb_sce The shoreline change envelope (SCE) value represents the greatest distance that covers all the shorelines intersected by a transect (no bias applied). U.S. Geological Survey 30.11 1176.66 meters The entity and attribute information provided here describes the tabular data associated with long-term shoreline change rates for Alabama. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units, NAD_1983_2011_UTM_Zone_16N. U.S. Geological Survey U.S. Geological Survey - ScienceBase mailing and physical address

Federal Center, Building 810, MS 302

Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov The dataset contains the polyline rates of shoreline change data, (SHP and other shapefile components), browse graphic, and the FGDC CSDGM metadata. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (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. Shapefile ArcGIS Pro version 3.5.5 Esri polyline shapefile (compressed to ZIP format) These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .html, 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 and include FGDC CSDGM-compliant metadata in HTML format. Transfer size is in MB. Unzip 0.20 https://doi.org/10.5066/P1JE2KSO https://www.sciencebase.gov/catalog/item/69e2b046b66b0195694c11e9 https://www.sciencebase.gov/catalog/file/get/69e2b046b66b0195694c11e9 The first link is to the USGS publication page, the second link is to the dataset page, and the third link downloads the data. None These data are available in a polyline shapefile format. The user must have software to read and process the data components of a shapefile. 20260622 Meredith G. Kratzmann U.S. Geological Survey mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA 508-548-8700 508-457-2310 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 local time