Gibbs, Ann E. Ohman, Karin A. Coppersmith, Ryan Richmond, Bruce M. 20240911 vector digital data (polyline) data release 10.5066/F72Z13N1 U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.5066/F72Z13N1 https://www.sciencebase.gov/catalog/item/663a5123d34e77890839b03f Gibbs, Ann E. Ohman, Karin A. Coppersmith, Ryan Richmond, Bruce M. 2017 2.0 data release 10.5066/F72Z13N1 Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey Suggested Citation: Gibbs, A.E., Ohman, K.A., Coppersmith, R., and Richmond, B.M., 2017, National Assessment of Shoreline Change: A GIS compilation of updated vector shorelines and associated shoreline change data for the north coast of Alaska, U.S. Canadian border to Icy Cape (ver. 2.0, September 2024): U.S. Geological Survey data release, https://doi.org/10.5066/F72Z13N1. https://doi.org/10.5066/F72Z13N1 This dataset consists of long-term (70 years) shoreline change rates for the mainland coast of Alaska sheltered by barrier islands from the Hulahula River to the Colville River. Rate calculations were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 5.1, an ArcGIS extension developed by the U.S. Geological Survey. Long-term rates of shoreline change were calculated using a linear regression rate-of-change method based on available shoreline data between 1947 and 2017. 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 are then used to calculate long-term rates. Coastal erosion is a persistent process along most open-ocean shores of the United States and affects both developed and natural coastlines. Along the Arctic coast of Alaska, coastal erosion is widespread and threatens communities, defense and energy-related infrastructure, and coastal habitat. As the coast changes, there are a wide range of ways that change can affect coastal communities, habitats, and the physical characteristics of the coast-including beach erosion, shoreline retreat, land loss, and damage to infrastructure. The U.S. Geological Survey (USGS) is responsible for conducting research on coastal change hazards, understanding the processes that cause coastal change, and developing models to forecast future change. To understand and adapt to shoreline change, accurate information regarding the past and present configurations of the shoreline is essential and a comprehensive, nationally consistent analysis of shoreline movement is needed. To meet this national need, the USGS is conducting an analysis of historical shoreline changes along open-ocean coasts of the United States and parts of the Great Lakes. In Alaska, coastlines sheltered from open-ocean wave conditions by barrier islands are also included in the analysis because of their importance to defense and energy-related infrastructure and to understand the similarities, differences, and linkages in coastal behavior and physical processes acting on exposed and sheltered permafrost coastlines. This dataset is one in a series of regionally focused reports on historical shoreline change. As more data are gathered, periodic updates are made, which provide information that can be used in multidisciplinary assessments of global change impacts. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology. 1947 2017 ground condition Complete None planned -150.231338 -144.137837 70.517392 69.963952 ISO 19115 Topic Category oceans environment geoscientificInformation Data Categories for Marine Planning Distributions Physical/Chemical Features USGS Thesaurus coastal processes geospatial datasets Marine Realms Information Bank (MRIB) keywords shoreline accretion shoreline erosion None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC Shoreline Shoreline change Digital Shoreline Analysis System DSAS USGS Metadata Identifier USGS:663a5123d34e77890839b03f Geographic Names Information System (GNIS) State of Alaska North Slope Beaufort Sea Staines River Sagavanirktok River Colville River Kuparuk River Harrison Bay Prudhoe Bay Canning River None Arctic National Wildlife Refuge United States of America Arctic ANWR No access constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov U.S. Geological Survey Generated as a feature class contained in a Personal Geodatabase by DSAS in ArcGIS. Gibbs, A.E. Richmond B.M. 2017 Gibbs, A.E., and Richmond, B.M., 2017, National Assessment of Shoreline Change: Summary Statistics for Updated Vector Shorelines and Associated Shoreline Change Data for the North Coast of Alaska, U.S.--Canadian Border to Icy Cape: U.S. Geological Survey Open-File Report 2017�1107, 21 p. https://doi.org/10.3133/ofr20171107 Ann E. Gibbs Bruce M. Richmond 2015 Gibbs, A.E., and Richmond, B.M., 2015, National assessment of shoreline change�Historical shoreline change along the north coast of Alaska, U.S.�Canadian border to Icy Cape: U.S. Geological Survey Open-File Report 2015�1048, 96 p. https://doi.org/10.3133/ofr20151048 Emily A. Himmelstoss Rachel E. Henderson Meredith G. Kratzmann Amy S. Farris 2021 Himmelstoss, E.A., Henderson, R.E., Kratzmann, M.G., and Farris, A.S., 2021, Digital Shoreline Analysis System (version 5.1) User Guide: U.S. Geological Survey Open-File Report 2021-1091. https://doi.org/10.3133/ofr20211091 https://pubs.er.usgs.gov/publication/ofr20211091 https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Emily A. Himmelstoss Amy S. Farris Rachel E. Henderson Meredith G. Kratzmann Ayhan Ergul Ouya Zhang Jessica L. Zichichi E. Robert Thieler 2018 Current software at time of use was 5.1. The second link directs to the DSAS project page. https://code.usgs.gov/cch/dsas/-/tree/v5.1?ref_type=tags 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 performed by the software. ShoreType and CalcEras attributes were added after rate calculations. The data have been quality checked. These data were generated using DSAS v. 5.1, an automated software program which does not perform checks for fidelity of the input features. The transects were visually inspected and sometimes manually adjusted within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines. The data have been quality checked. This dataset contains the transects automatically generated by the DSAS software application that were used to calculate shoreline change rates along sections of the north coast of Alaska, from the Hulalula River to the Colville River, where shoreline position data were available. Additional transects may have been generated but did not intersect the shoreline dates specified. The transect serves as a reference point along which measurements are calculated by the Digital Shoreline Analysis System (DSAS) software. It does not correspond to any real-world feature. The uncertainty of the linear regression rate included with the transect file is estimated by the elements LR2, LSE and LCI90. See the attribute definition of each for more information. U.S. Geological Survey 2024 shapefile online U.S. Geological Survey https://www.sciencebase.gov/catalog/file/get/663a5297d34e77890839b04d Digital Resources 2024 ground condition DSAS baseline DSAS baseline, from this same data release, used for calculation of shoreline change rates. U.S. Geological Survey 2024 shapefile online U.S. Geological Survey https://www.sciencebase.gov/catalog/file/get/663a5321d34e77890839b050 Digital Resources 1947 2017 ground condition DSAS shoreline DSAS shoreline file, from this same data release, used for calculation of shoreline change rates. Transect features were generated using DSAS v5.1 in ArcMap v10.8.1. Parameters Used: Baseline Layer= CentralBeaufort_sheltered_baseline, Baseline ID Filed=ID, baseline placement=midshore, Baseline Orientation=Land is to the LEFT, Search Distance From Baseline=variable, Transect Spacing=50 meters, Smoothing Distance=500 meters. 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. DSAS baseline 2023 Some transects were manually edited in ArcMap v10.8.1 to ensure they intersected all shorelines and were as close to perpendicular as possible. 2023 Rate calculations performed using DSAS v5.1 in ArcMap v10.8.1 on selected shoreline features. Parameters Used: Shoreline Layer= CentralBeaufort_Shorelines, Shoreline Date Field=DATE_, Shoreline Uncertainty Field=Uncy, Default Data Accuracy=0 meters, Intersection Parameters=Seaward Intersection, Statistics to Calculate =[Shoreline Change Envelope (SCE)], [Net Shoreline Movement (NSM)],[Linear Regression Rate (LRR)], Confidence Interval=90 percent. For short-term rate calculations as subset of years (1979-2017) was selected. DSAS shoreline 2023 The exported transect shapefile was projected in Esri's ArcToolbox (v10.8.1) > Data Management Tools > Projections and Transformations > Feature > Project. Parameters: input projection � NAD_1983_2011_Alaska_Albers; output projection - geographic coordinates (WGS84); transformation = WGS_1984_(ITRF00)_To_NAD_1983. 2024 Vector String 4296 0.0000001 0.0000001 Decimal degrees WGS_1984 WGS 84 6378137.0 298.257224 Attribute Table Table containing attribute information associated with the data set. U.S. Geological Survey FID Internal feature number Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry Esri Coordinates defining the feature TransectID A permanent and unique identification number for each transect in the output rates table calculated by DSAS. Himmelstoss and others (2021) Multiple unique numbers 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. Himmelstoss and others (2021) Multiple unique numbers GroupID Values in this field correlate to the optional baseline attribute field �DSAS_group� (Group_) and are assigned by DSAS if selected by user. This field is used to aggregate sections of the coast into groups. Here they represent coastal sub-region ID as defined in Gibbs and Richmond (2017). Himmelstoss and others (2021) and Gibbs and Richmond (2017) 2 Hulahula River to the Staines River U.S. Geological Survey 3 Staines River to the Sagavanirktok River U.S. Geological Survey 4 Sagavanirktok River to the Colville River U.S. Geological Survey 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. U.S. Geological Survey 3090 7671 Azimuth Used to record the azimuth of the transect measured in degrees clockwise from north. U.S. Geological Survey 2.96 355.43 ShrCount The total number of shorelines intersected by the transect and used for change analysis. U.S. Geological Survey 3 5 TCD Total cumulative distance in meters from start of baseline to transect location. U.S. Geological Survey 224159.74 664955.67 SHAPE_Leng Length of transect in meter units. This field is automatically generated and maintained when data are within a geodatabase. U.S. Geological Survey 0 unlimited SCE The shoreline change envelope (SCE) reports a distance, not a rate. The SCE is the distance between the shoreline farthest from and closest to the baseline at each transect. This represents the total change in shoreline movement for all available shoreline positions and is not related to their dates. U.S. Geological Survey 1.11 681.74 Meters NSM The net shoreline movement (NSM) reports the distance between the oldest and youngest shorelines for each transect. This represents the total distance between the oldest and youngest shorelines. U.S. Geological Survey -588.73 167.47 Meters 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. 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) and negative values indicating erosion (shoreline retreat). U.S. Geological Survey -17.42 5.61 LR2 The R-squared statistic, or coefficient of determination, is the percentage 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 1 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 point minus two. The square root is taken of the result. U.S. Geological Survey 0.06 249.47 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 (also called the standard deviation) 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 0.01 27.7 ShoreType User defined shoreline type U.S. Geological Survey Sheltered Mainland A large, continuous extent of land that does not include offshore islands or other detached territories and is sheltered from direct wave energy by offshore islands. U.S. Geological Survey Sheltered Barrier Spit Deposits of sediment extending from the mainland into a body of water and sheltered from direct wave energy by offshore islands. U.S. Geological Survey Sheltered Barrier Island Deposits of sediment that are detached from the coast, run parallel to the coastline, and are sheltered from direct wave energy by offshore islands. U.S. Geological Survey Sheltered Barrier Beach Deposits of sediment that run parallel to the coastline, are attached to the mainland at both ends, front a body of water, and are sheltered from direct wave energy by offshore islands. U.S. Geological Survey Sheltered Island Portions of offshore islands sheltered from direct wave energy. U.S. Geological Survey Sheltered Artificial Artificial or constructed land that is sheltered from direct wave energy by offshore islands. U.S. Geological Survey CalcEras Decade or era of shorelines that were used to calculate shoreline change rates. U.S. Geological Survey Multiple unique values listing the decades or eras of shorelines The entity and attribute information provided here describes the tabular data associated with the data set. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data set. U.S. Geological Survey U.S. Geological Survey - Science Base mailing and physical address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 CA 888-275-8747 sciencebase@usgs.gov These data are available in shapefile format contained in a single zip file, which also includes CSDGM FGDC-compliant 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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Shapefile ArcGIS Desktop 10.8.1 Esri polyline 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 and include FGDC CSDGM-compliant metadata. Use WinZip or equivalent 0.35 https://www.sciencebase.gov/catalog/file/get/663a5123d34e77890839b03f https://www.sciencebase.gov/catalog/item/663a5123d34e77890839b03f Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the zipped file of data and metadata. The second link points to a landing page with metadata and data. The third link points to the landing page for the overall data release. 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. 20240911 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998