Wave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia

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Frequently anticipated questions:

What does this data set describe?

Title:
Wave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia
Abstract:
This product provides spatial variations in wave thrust along shorelines in the Chesapeake Bay. Natural features of relevance along the Bay coast are salt marshes. In recent times, marshes have been eroding primarily through lateral erosion. Wave thrust represents a metric of wave attack acting on marsh edges. The wave thrust is calculated as the vertical integral of the dynamic pressure of waves. This product uses a consistent methodology with sufficient spatial resolution to include the distinct features of each marsh system. Waves under different climatological wind forcing conditions were simulated using the coupled ADCIRC/SWAN model system. The estuarine and bay areas are resolved with horizontal resolutions of order hundreds of meters. The simulations provide the wave height, period, and direction needed to calculate wave thrust. We consider the frequency of occurrence of each wind magnitude and direction bin for each location to reconstruct a weighted-average wave thrust that considers coastal orientation with regard to dominant wave direction. The resulting wave thrust is then mapped along the shoreline of Chesapeake Bay to generate the present product.
  1. How might this data set be cited?
    Aretxabaleta, Alfredo L, Defne, Zafer, and Ganju, Neil K, 20210913, Wave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia: data release DOI:10.5066/P9SLXS0G, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Aretxabaleta, A.L., Defne, Z., and Ganju, N.K., 2021, Wave thrust values at point locations along the shorelines of Chesapeake Bay, Maryland and Virginia: U.S. Geological Survey data release, https://doi.org/10.5066/P9SLXS0G.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -77.5347
    East_Bounding_Coordinate: -75.5631
    North_Bounding_Coordinate: 39.7211
    South_Bounding_Coordinate: 36.6702
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/61029353d34ef8d7055e38a4?name=Ches_wavethrust_1km.png (PNG)
    Graphic that shows Chesapeake Bay wave thrust points at a 1 kilometer resolution.
    https://www.sciencebase.gov/catalog/file/get/61029353d34ef8d7055e38a4?name=Ches_wavethrust_100m.png (PNG)
    Graphic that shows Chesapeake Bay wave thrust points at a 100 meter resolution.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2021
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set.
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0197561039. Longitudes are given to the nearest 0.0250207345. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North_American_Datum_1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp
    Attribute information associated with the wave thrust along the Chesapeake Bay shoreline with a resolution of 100 m. The data are available in shapefile and CSV format. The attributes are the same except the shapefile specific attributes (FID, Shape) are not present in the CSV file. The dataset has 229589 data records. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    lon
    Longitude coordinate in decimal degrees, NAD83. Negative value indicates Western hemisphere (Source: USGS)
    Range of values
    Minimum:-77.534658
    Maximum:-75.563124
    lat
    Latitude coordinate in decimal degrees, NAD83 (Source: USGS)
    Range of values
    Minimum:36.670174
    Maximum:39.721105
    wavethrust
    Wave thrust acting against the shoreline (100 m) (Source: USGS)
    Range of values
    Minimum:0.0
    Maximum:3.30114222
    Units:KiloNewtons per meter (kN m-1)
    Chesapeake_shoreline_wave_thrust_HSOFS_dir.shp
    Attribute information associated with the wave thrust along the Chesapeake Bay shoreline with a resolution of 1km (1000 m). The data are available in shapefile and CSV format. The attributes are the same except the shapefile specific attributes (FID, Shape) are not present in the CSV file. The dataset has 16813 data records. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    lon
    Longitude coordinate in decimal degrees, NAD83. Negative value indicates Western hemisphere (Source: USGS)
    Range of values
    Minimum:-77.417711
    Maximum:-75.573461
    Units:degree longitude
    lat
    Latitude coordinate in decimal degrees, NAD83 (Source: USGS)
    Range of values
    Minimum:36.711911
    Maximum:39.621037
    Units:degree latitude
    wavethrust
    Wave thrust acting against the shoreline (1 km) (Source: USGS)
    Range of values
    Minimum:0.0
    Maximum:3.30232066
    Units:KiloNewtons per meter (kN m-1)
    Entity_and_Attribute_Overview:
    In this dataset, the wave thrust along the shoreline of Chesapeake Bay has been provided. Wave thrust provides a metric of potential erosion of the parts of the shoreline covered with saltmarsh. Recently, marsh edge erosion has been linked to wave attack and specifically wave thrust. In this product, climatological wave thrust is estimated from wave fields forced with different wind magnitudes and directions that match the climatological wind conditions in each area. Wave thrust is then evaluated from the climatological wave conditions and mapped along the shoreline.
    This metadata file has information for two shapefiles (Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp and Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.shp) and attributes specific to each one are described.
    Entity_and_Attribute_Detail_Citation: USGS

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Alfredo L Aretxabaleta
    • Zafer Defne
    • Neil K Ganju
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Alfredo Aretxabaleta
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 X2204 (voice)
    aaretxabaleta@usgs.gov

Why was the data set created?

The wave thrust data were created to be used in evaluating the spatial variation of the response and resiliency of the salt marsh to wave attack.

How was the data set created?

  1. From what previous works were the data drawn?
    GULF_ATLANTIC_ESI (source 1 of 2)
    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Office of Response and Restoration (OR&R), Emergency Response Division (ERD), Seattle, Washington., 201705, National Environmental Sensitivity Index Shoreline: GULF/ATLANTIC ESI, PACIFIC ESI: ESIL (ESI Shoreline Types - Lines): National ESI Shoreline Gulf_Atlantic ESI, Pacific ESI, NOAA's Ocean Service, Office of Response and Restoration (OR&R), Emergency Response Division (ERD), Seattle, Washington.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Scale_Denominator: 24000
    Source_Contribution: Source input was used in generating points along the shoreline.
    ERA5_WIND (source 2 of 2)
    copernicus-support@ecmwf.int, ECMWF, 20180614, ERA-5 hourly east-west and north-south wind components at 10 meters height.

    Online Links:

    Other_Citation_Details: ERA5 hourly data on single levels from 1979 to present
    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    The east-west and north-south wind components are combined to produce bins of wind speed and direction
  2. How were the data generated, processed, and modified?
    Date: 2020 (process 1 of 7)
    This process step and all subsequent process steps were performed by the same person, Alfredo Aretxabaleta in Matlab (ver. 2016b), unless otherwise stated.
    The latest European Centre for Medium Range Weather Forecast (ECMWF) Re-Analysis (ERA-5, https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era5) model solution was extracted for all areas around the US east coast shoreline. The hourly data for the east-west and north-south wind components at 10 m height were downloaded from https://doi.org/10.24381/cds.adbb2d47 on 20 November 2019. Data for the period January 2000 to December 2018 was used for each location. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alfredo Aretxabaleta
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x. 2204 (voice)
    aaretxabaleta@usgs.gov
    Data sources used in this process:
    Date: 2020 (process 2 of 7)
    The east-west and north-south wind components are combined to produce wind speed and direction (degrees from True North) using a Matlab code that transforms and rotates vectors from the vector components to magnitude and direction.
    The wind speeds and directions were binned to create a set of wind roses for each coastal location. Wind direction was binned in 12 intervals using 30-degree intervals: Bin 1: -15 (345) to 15 deg N; Bin 2: 15 to 45 deg N; Bin 3: 45 to 75 deg N; Bin 4: 75 to 105 deg N; Bin 5: 105 to 135 deg N; Bin 6: 135 to 165 deg N; Bin 7: 165 to 195 deg N; Bin 8: 195 to 225 deg N; Bin 9: 225 to 255 deg N; Bin 10: 255 to 285 deg N; Bin 11: 285 to 315 deg N; Bin 12: 315 to 345 deg N
    and wind speeds were binned with the following ranges: Bin 1: 0-2 m/s; Bin 2: 2-4 m/s; Bin 3: 4-6 m/s; Bin 4: 6-8 m/s; Bin 5: 8-12 m/s; Bin 6 12-38 m/s
    Date: 2020 (process 3 of 7)
    A matrix of model simulations (72 total simulations) of the ADCIRC/SWAN (version 53.04, https://adcirc.org/home/documentation/users-manual-v53/; Dietrich et al. [2011]) modeling system were conducted with different wind directions (12) and intensities (6). A constant wind for each direction centered on the mid-value (0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 deg N) and with speeds centered at the mid-value of each bin (1, 3, 5, 7, 10, 25 m/s) were imposed for the entire model domain.
    The unstructured grid is the one from the Hurricane Surge On-demand Forecast System (HSOFS, https://www.weather.gov/sti/coastalact_surgewg; Moghimi et al. [2020]). HSOFS is an unstructured finite element grid that extends westward to the 65 W longitude and resolves the entire east coast of the United States and the Gulf of Mexico. The grid contains 1.8 million grid points resulting in horizontal resolutions as low as 130m with most coastal grid elements being 300-400m in size. The grid extends overland to approximately the 10 m elevation (NAVD88).
    The model was run in coupled mode, initialized from rest, and run until steady-state was achieved. The maximum water levels, significant wave heights, and peak periods were extracted from the end of each simulation.
    Many papers describe the development and usage of the ADCIRC computational model, but basic details can be found in Luettich et al. (1992) and Dietrich et al. (2011).
    References:
    Dietrich, J.C., Zijlema, M., Westerink, J.J., Holthuijsen, L.H., Dawson, C., Luettich Jr, R.A., Jensen, R.E., Smith, J.M., Stelling, G.S. and Stone, G.W., 2011, Modeling hurricane waves and storm surge using integrally-coupled, scalable computations. Coastal Engineering, Vol 58(1), pp.45-65.
    Luettich, R.A.; Westerink, J.J.; Scheffner, N.W. 1992, ADCIRC: An Advanced Three-Dimensional Circulation Model for Shelves, Coasts, and Estuaries; Report 1: Theory and Methodology of ADCIRC-2DDI and ADCIRC-3DL; Technical Report CERC-TR-DRP-92-6; U.S. Army Corps of Engineers, U.S. Department of the Army: Washington, DC, USA.
    Moghimi, S., Van der Westhuysen, A., Abdolali, A., Myers, E., Vinogradov, S., Ma, Z., Liu, F., Mehra, A. and Kurkowski, N., 2020. Development of an ESMF based flexible coupling application of ADCIRC and WAVEWATCH III for high fidelity coastal inundation studies. Journal of Marine Science and Engineering, Vol. 8(5), p.308.
    Date: 2020 (process 4 of 7)
    In order to estimate wave thrust, the orientation of the shoreline with regard to the incident waves causing thrust needed to be determined. We calculated shoreline orientation from the unstructured grid by following these steps:
    a) We extracted shoreline segments (zero meter mean sea level contour) from grid using a Matlab code.
    b) We calculated the angle with respect to True North of each shoreline segment.
    c) We determined the wet (ocean) side of each segment by comparing the bathymetric/topographic elevation of the segment (0 m) with that of a point perpendicular to the segment and 100m from it. If the perpendicular point is deeper, then the ocean/bay is to that side.
    Depth_100m_perpen = depth(xmid+abs((y2-y1)/100), ymid+abs((x2-x1)/100)), where xmid, ymid are the coordinates of the center point of the segment, x1, y1 are the coordinates of one of the endpoints of the segment, and x2,y2 are the coordinates of the other endpoint of the segment. Depth_100m_perpen is the depth at a point perpendicular to the segment and 100m from it.
    d) Finally, we determine the angle between the shore-normal direction and the incoming wave.
    Date: 2020 (process 5 of 7)
    The climatological wave thrust was calculated as the weighted average of the wave conditions from each direction that was exposed to the waves coming from the ocean/bay side.
    The weights for each location were extracted from the wind distribution of directions and magnitudes from the climatological wind roses. Based on the shoreline orientation, the incident directions coming from land were assigned a weight of zero. The rest of directions were adjusted so that maximum weights correspond to the direction perpendicular to shore. The wave thrust estimation was conducted following the equations:
    Based on Tonelli et al. (2010), first, the above mean sea level component (accounting for the hydrostatic pressure from wind waves) is defined as: WTasl = 0.5*ρ*g*Hwave^2, where ρ is the density of water, g is the acceleration due to gravity and Hwave is the significant wave height
    Second, the dynamic pressure of wind waves can be calculated as WTbsl = ρ*g*Kp*Hwave, where Kp is the pressure-response factor accounting for the dynamic component due to water particle acceleration and can be calculated as Kp = cosh(k*(h+z)) / cos(k*h), where h is the marsh elevation with respect to mean sea level, z is the water level, and k is the wave number.
    As wave thrust from dynamic pressure depends on water depth, we followed the approach of Tonelli et al. (2010) with a reduction in wave thrust proportional to the water depth on the marsh platform. Next, the thrust from the two components can be added to give the total thrust due to wave attack. WTtotal = WTasl + WTbsl
    Based on the direction of the waves and grid orientation, the fraction of total thrust that is normal to the marsh edge is calculated
    The model solutions provided significant wave height, peak wave period, and wave direction. As the below sea level expression requires wave number, the dispersion relationship was used to calculate wave number from wave period and water depth.
    Reference: Tonelli, M., Fagherazzi, S., and Petti, M., 2010, Modeling wave impact on salt marsh boundaries: Journal of Geophysical Research, Vol. 115, C09028, https://doi.org/10.1029/2009JC006026.
    Date: 2020 (process 6 of 7)
    This processing step was performed by Zafer Defne in ArcMap (ver. 10.7.1) using tools from ArcToolbox. For complex operations, names of specific tools used are given in CAPITAL letters (any critical parameters used are given in parentheses, separated by a semicolon, immediately after the tool name). The input (GULF_ATLANTIC_ESI) and output file names are provided in [square brackets] when necessary. Units for length and area calculations are meters (m) and square meters (m2) unless otherwise stated.
    In this step we generate points along the high resolution (1/24,000 scale) shoreline. We generate a 1-km spaced and a 100-m spaced dataset.
    Download the 2017 National Environmental Sensitivity Index Shoreline (Contiguous U.S. shoreline) dataset from NOAA Office of Response and Restoration's Environmental Sensitivity Index (ESI) maps inventory. See https://response.restoration.noaa.gov/esi_download.
    Crop the [GULF_ATLANTIC_ESI] line features in the GULF_ATLANTIC_ESI geodatabase file to the Chesapeake Bay interior from the bay-mouth to Summit Bridge on the Chesapeake-Delaware Canal, and to Conowingo Dam on the Susquehanna River.
    GENERATE POINTS ALONG LINES (Point Placement =Distance; Distance=0.009 Decimal degrees) along the cropped shoreline approximately with 1-km spacing to generate the point features [Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.shp].
    GENERATE POINTS ALONG LINES (Point Placement =Distance; Distance=0.0009 Decimal degrees) along the cropped shoreline approximately with 100-m spacing to generate the point features [Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp].
    The distance along the shoreline is calculated straight out from the source data. Therefore, the spacing between adjacent points in either the 100m or 1km datasets might be much smaller than 100m or 1km, as the spacing is from the original data and not between points in the extracted points. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Zafer Defne
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-457-2254 (voice)
    508-548-8700 x. 2310 (FAX)
    zdefne@usgs.gov
    Data sources used in this process:
    • GULF_ATLANTIC_ESI
    Data sources produced in this process:
    • Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.shp
    • Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp
    Date: 2020 (process 7 of 7)
    In the final step, the wave thrust calculated on the ADCIRC grid (HSOFS) is linearly interpolated onto the shoreline positions for the Chesapeake Bay with either the 100-meter spacing or the 1-km spacing between shoreline points. The interpolation was conducted using the scatteredInterpolant.m function in Matlab with the linear interpolation option. In Matlab v2016b, the function dlmwrite.m was used to export the data to CSV format. The shapefile was created in ArcGIS from the CSV files. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alfredo Aretxabaleta
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x. 2204 (voice)
    aaretxabaleta@usgs.gov
    Data sources produced in this process:
    • Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.shp
    • Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp
  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?
    The wave thrust values represent model climatological conditions simulated along the shoreline. Climatological wind conditions used as forcing could have inaccuracies due to resolution restrictions and physical processes misrepresentations. We take the European Centre for Medium Range Weather Forecast (ECMWF) Re-Analysis (ERA-5) simulations as our best guess for the climatological conditions in the area. The accuracy of the wave model simulations is also limited by resolution and the choice of physical parameters. The model parameters were chosen following the expert opinion of the modeling group that conducts forecast simulations for the east coast of the United States on the same unstructured grid. Finally, a visual comparison between the current wave thrust analysis data and published results of wave attack in the Chesapeake Bay was conducted to qualitatively assure accuracy.
  2. How accurate are the geographic locations?
    The horizontal accuracy is inherited from the source shoreline dataset, the 1:24,000 scale National Environmental Sensitivity Index Shoreline (Contiguous U.S. shoreline) dataset from NOAA Office of Response and Restoration's Environmental Sensitivity Index (ESI) shorelines.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    The wave thrust data for the Chesapeake are bound to the input shoreline data, which represent shorelines on the interior of the Bay: from the bay-mouth to Summit Bridge on the Chesapeake-Delaware Canal, and to Conowingo Dam on the Susquehanna River. A detailed on-the-ground analysis of a single site may result in a different wave thrust than established through this analysis.
  5. How consistent are the relationships among the observations, including topology?
    The data provided matches the wave source information and falls within the expected ranges for wave thrust. The geospatial data were checked for integrity during the shoreline extraction process and the shoreline points were verified to make sure that they fall on the shorelines. Possible data duplicates have been checked and eliminated.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
These data are defined for scientific research purposes and should not be used as a sole source of reference for any regulations and policy making. 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 source of this information.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: GS ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    United States

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The dataset consists of two shapefiles: Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.shp and associated files (100-m resolution) and Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.shp (1-km resolution). The CSV files comparable to the shapefiles are also included (Chesapeake_shoreline_wave_thrust_HSOFS_dir_100m.csv and Chesapeake_shoreline_wave_thrust_HSOFS_dir_1km.csv). Additionally, there are two browse graphics (Ches_wavethrust_1km.png and Ches_wavethrust_100m.png) and FGDC CSDGM metadata in XML format (Ches_wavethrust_hsofs.xml).
  3. What legal disclaimers am I supposed to read?
    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. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Not for navigational use.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Sep-2021
Metadata author:
U.S. Geological Survey
Attn: Alfredo Aretxabaleta
Oceanographer
384 Woods Hole Road
Woods Hole, MA
US

508-548-8700 x. 2204 (voice)
aaretxabaleta@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P9SLXS0G/Ches_wavethrust_hsofs.faq.html>
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