2D XBeach model input files – Unalakleet, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title: 2D XBeach model input files – Unalakleet, Alaska
Abstract:
The data sets provided here consist of 2D XBeach model files and sample input files used for Coastal Storm Modeling System (CoSMoS) simulations of flood and erosion hazards in Unalakleet, Alaska. The models produce outputs for a suite of hazard products (see products in this release), such as flood depths, flood extents, and erosion and sedimentation. In this release, example forcing files for conditions with a 100-year return period coastal storm and a sea level rise of 0.5 m are provided, in addition to all other files needed to run the model in surfbeat and nonhydrostatic modes.
Supplemental_Information:
Work was funded by US Geological Survey Climate Adaptation Science Center Project EN05ES9 (see Projects - Climate Adaptation Science Centers). For more information on coastal storm modeling, see https://www.usgs.gov/centers/pcmsc/science/coastal-storm-modeling-system-cosmos.
  1. How might this data set be cited?
    Nederhoff, Kees, Erikson, Li H., and Engelstad, Anita C., 20250926, 2D XBeach model input files – Unalakleet, Alaska: data release DOI: 10.5066/P139S3GK, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Erikson, Li H., Engelstad, Anita C., Nederhoff, Kees, Nereson, Alexander L., Gibbs, Ann E., Williams, Dee M., Hayden, Maya K., and Herman-Mercer, Nicole, 2025, CoSMoS-AK Modeled flood and erosion hazards, Unalakleet, Alaska: data release DOI: 10.5066/P139S3GK, U.S. Geological Survey, Alaska Climate Adaptation Science Center, Anchorage, AK.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Erikson, L.H., Engelstad, A.C., Nederhoff, K., Nereson, A.L., Gibbs, A.E., Williams, D.M., Hayden, M.K., and Herman-Mercer, N., 2025, CoSMoS-AK Modeled Flood and Erosion Hazards at Unalakleet - Coastal Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P139S3GK.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -160.860036
    East_Bounding_Coordinate: -160.643346
    North_Bounding_Coordinate: 63.956505
    South_Bounding_Coordinate: 63.835339
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2025
    Currentness_Reference:
    publication year
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: text files
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 4
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -159.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 500000.0
      False_Northing: 0.00
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 0.55
      Ordinates (y-coordinates) are specified to the nearest 0.8
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD83.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: North American Vertical Datum of 1988
      Depth_Resolution: 0.01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?
    2D_XBeach_ModelInput_SB_Unalakleet.zip and 2D_XBeach_ModelInput_NH_Unalakleet.zip
    One zip file for the surfbeat (SB) model and one for the non-hydrostatic (NH) model, each with sample time-series forcing data (stormtide.txt and jonswap.txt) and all necessary input files. (Source: Producer defined)
    Entity_and_Attribute_Overview:
    Model setup files include all files necessary to run XBeach model simulations first in surfbeat mode and then, after updating the change in bathymetry with the surfbeat output, in non-hydrostatic mode. To provide the user with an example, the boundary conditions (jonswap and stormtide files) are included here for a projected 100-year return period storm and a sea level rise of 0.50 mm.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Kees Nederhoff
    • Li H. Erikson
    • Anita C. Engelstad
  2. Who also contributed to the data set?
    Resources supporting this work were provided by USGS Advanced Research Computing (Falgout and others, 2024).
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

This product was created to fulfill the Bureau-wide vision of an integrated, predictive science capability to support Alaska Native communities in building resiliency from natural disasters, sovereignty and self-determination, and emergency response and planning capacity.

How was the data set created?

  1. From what previous works were the data drawn?
    TBDEM (source 1 of 1)
    Nereson, Alexander L., Gibbs, Ann E., and Erikson, Li H., 2025, Topobathymetric digital elevation models – coastal Alaska: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: online database
    Source_Contribution: Topographic and bathymetry elevation data used in models
  2. How were the data generated, processed, and modified?
    Date: 01-Nov-2024 (process 1 of 1)
    Model grids (x.grd, y.grid), elevations (bed.dep, in meters above NAVD88) and other XBeach-specific setup files (params, disch_loc_file, disch_timeseries_file, jonswap, waterlevel_ini, ne_layer, bedfricfile, and stormtide) were developed for surfbeat (XB-SB) and non-hydrostatic (XB-NH)simulations. See Deltares manual (2025) for a description of model files and differences between the surfbeat and non-hydrostatic modes. The XB-SB and XB-NH models can be run independent of each other or sequentially to leverage the strengths of both XBeach modes for a comprehensive simulation of wave dynamics, particularly in the context of swash zone (active beach area) processes and wave runup. The SB mode is computationally efficient and well-suited for capturing long-wave (infragravity) variations and their interactions with the shoreline, including morphodynamic change (erosion and sedimentation). The NH mode provides a detailed, wave-resolved simulation that includes individual wave overtopping. Models are set up in the cartesian coordinate system (Universal Transverse Mercator (UTM) zone 4 N) and elevations are referenced to the North American Vertical Datum of 1988 (NAVD88). Bed level data files of both the XB-SB and XB-NH models were populated using nearest grid-point mean TBDEM elevations, except in regions of breakwaters, constructed berms, and elevated roads, which were manually digitized to ensure that maximum elevations were accurately represented. Bed friction was populated using established Manning n values related to land-use map data (OCM 2025; Brunner 2024) but capped at a friction value of 0.028. Model setup was calibrated and validated against observation-based flood extents and surveyed high-water marks (NCDC 2019; Horen and others 2022, USGS, 2024). Data sources used in this process:
    • TBDEM
  3. What similar or related data should the user be aware of?
    Brunner, G.W., 2024, HEC-RAS River Analysis System 2D User’s Manual. Version 6.7_Beta3.

    Online Links:

    Other_Citation_Details:
    Brunner, G.W., 2024. HEC-RAS River Analysis System 2D User’s Manual. Version 6.7_Beta3. US Army Corps of Engineers. Hydrologic Engineering Center. https://www.hec.usace.army.mil/confluence/rasdocs/r2dum/latest/developing-a-terrain-model-and-geospatial-layers/creating-land-cover-mannings-n-values-and-impervious-layers
    Deltares, 2025, XBeach online manual documentation..

    Online Links:

    • xbeach.readthedocs.io

    Other_Citation_Details:
    Deltares, 2025, Beach online manual documentation, Available online: xbeach.readthedocs.io (accessed 01 February 2025)
    Falgout, J.T., Gordon, J., Williams, B., and Davis, M.J., 2024, USGS Advanced Research Computing, USGS Denali Supercomputer..

    Online Links:

    Other_Citation_Details:
    Falgout, J.T., Gordon J., Williams B., Davis M. J., USGS Advanced Research Computing, USGS Denali Supercomputer: U.S. Geological Survey, https://doi.org/10.5066/P9PSW367
    Horen, K.C., Poisson, A.C., Siemsen, Z.J., Donohue, J.M., Widmer, K.L., Adams, J.D., and Overbeck, J.R., 2022, Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022.

    Online Links:

    Other_Citation_Details:
    Horen, K.C., Poisson, A.C., Siemsen, Z.J., Donohue, J.M., Widmer, K.L., Adams, J.D., and Overbeck, J.R., 2022, Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022: Alaska Division of Geological & Geophysical Surveys Raw Data File 2022-14, 8 p. https://doi.org/10.14509/30909
    National Climatic Data Center (NCDC), 2019, Storm data.

    Other_Citation_Details:
    National Climatic Data Center (NCDC), 2019, Storm data, last accessed May 2019. http://www.ncdc.noaa.gov/IPS/sd/sd.html
    Office for Coastal Management (OCM), 2025, 2020-2023 CCAP Version 2 Impervious Cover.

    Other_Citation_Details:
    Office for Coastal Management, 2025: 2020-2023 CCAP Version 2 Impervious Cover, https://www.fisheries.noaa.gov/inport/item/70563
    U.S. Geological Survey, 2024, Short-Term Network Data Portal.

    Other_Citation_Details:
    U.S. Geological Survey, 2025, Short-Term Network Data Portal, accessed on October 15, 2024, at http://water.usgs.gov/floods/FEV/

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Model setup was validated against observation-based storm flood elevations (NCDC 2019; Horen and others 2022, USGS, 2024). However, accurate historic water level recordings and detailed observations of floodings are sparse and vary between communities.
  2. How accurate are the geographic locations?
    Data are concurrent with topobathymetric digital elevation model (TBDEM, see Nereson and others, 2025) locations.
  3. How accurate are the heights or depths?
    Model bathymetry and topography are accurate within the published topobathymetric data (DOI: doi.org/10.5066/P13BXTXV) and interpolation onto model grid
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented.
  5. How consistent are the relationships among the observations, including topology?
    Data have undergone quality checks and fall within expected/reasonable ranges.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints
Use_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. These data are marked with a Creative Common CC0 1.0 Universal License. Please recognize and acknowledge the U.S. Geological Survey as the originator of the dataset and in products derived from these data. These data are not intended to be used for navigation.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available as text files contained in two zip files accompanied by CSDGM FGDC-compliant metadata.
  3. What legal disclaimers am I supposed to read?
    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. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Zip file (2D_XBeach_ModelInput_SB_Unalakleet.zip) contains 11 model input files for the surfbeat model in format text Size: 8.6
      Network links: https://doi.org/10.5066/P139S3GK
      Data format: Zip file (2D_XBeach_ModelInput_NH_Unalakleet.zip) contains 11 model input files for the non-hydrostatic model in format text Size: 12.7
      Network links: https://doi.org/10.5066/P139S3GK
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    The text data can be viewed with any text reading software.

Who wrote the metadata?

Dates:
Last modified: 26-Sep-2025
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P139S3GK/2D_XBeachModels_Unalakleet_metadata.faq.html>
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