Projected groundwater head along the North and South Carolina coasts

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Frequently anticipated questions:

What does this data set describe?

Title:
Projected groundwater head along the North and South Carolina coasts
Abstract:
Seamless unconfined groundwater heads for U.S. coastal North and South Carolina groundwater systems were modeled with homogeneous, steady-state MODFLOW simulations. The geographic extent examined was limited primarily to low-elevation (land surface less than approximately 10 m above mean sea level) areas. Steady-state MODFLOW groundwater flow models were used to obtain detailed (50-meter-scale) predictions over large geographic scales (100s of kilometers) of groundwater heads for both current and future sea-level rise (SLR) scenarios (0, 0.25, 0.5, 1, 1.5, 2, 2.5, and 3 m) using 3 spatially varying hydraulic conductivities (K); one based on published K’s, one with published K’s reduced by a factor of 10 (K*0.1), and one with published K’s increased by a factor of 10 (K*10) to assess the sensitivity of model results to K. All models had variable thicknesses corresponding to published transmissivities. The models were run with a local mean higher-high water (MHHW) marine boundary condition and with groundwater reaching the land surface removed from the model, simulating loss via natural drainage.
Supplemental_Information:
This data release was funded by the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157) for North Carolina and South Carolina. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Befus, Kevin M., Hoover, Daniel J., and Barnard, Patrick L., 20230128, Projected groundwater head along the North and South Carolina coasts: data release DOI: 10.5066/P9W91314, U.S. Geological Survey, Pacific Coastal and Marine Science Center Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Barnard, Patrick L., Befus, Kevin, Danielson, Jeffrey J., Engelstad, Anita C., Erikson, Li H., Foxgrover, Amy C., Hardy, Matthew W., Hoover, Daniel J., Leijnse, Tim, Massey, Chris, McCall, Robert, Nadal-Caraballo, Norberto C., Nederhoff, Kees, Ohenhen, Leonard, O’Neill, Andrea C., Parker, Kai A., Shirzaei, Manoocher, Su, Xin, Thomas, Jennifer A., Ormondt, Maarten van, Vitousek, Sean F., Vos, Kilian, and Yawn, Madison C., 2023, Future coastal hazards along the U.S. North and South Carolina coasts: data release DOI: 10.5066/P9W91314, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -81.469853
    East_Bounding_Coordinate: -75.444681
    North_Bounding_Coordinate: 36.630934
    South_Bounding_Coordinate: 31.870736
  3. What does it look like?
    GWHazards_Head_browse_graphic.png (PNG)
    Map showing groundwater head results along the coasts of North and South Carolina for the K x 1 and present-day sea-level rise (0m) scenario. Colors represent groundwater head (elevation) relative to the NAVD88 vertical datum.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-Jan-2008
    Ending_Date: 2022
    Currentness_Reference:
    oldest dataset used through year of publication
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GeoTIFF
  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: 17
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -81.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 50.000000
      Ordinates (y-coordinates) are specified to the nearest 50.000000
      Planar coordinates are specified in meters
      The horizontal datum used is GCS WGS 1984.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: NAVD88
      Depth_Resolution: 0.001
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?
    projected coastal groundwater head
    Geotiffs of projected coastal groundwater head for the State, SLR, and K case specified (Source: originators at United States Geological Survey, Pacific Coastal and Marine Science Center)
    Projection of coastal groundwater head for given State, SLR, and K case specified
    Groundwater head (Source: model determined)
    Range of values
    Minimum:-0.058
    Maximum:53.609
    Units:meters
    Resolution:0.001

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Kevin M. Befus
    • Daniel J. Hoover
    • Patrick L. Barnard
  2. Who also contributed to the data set?
  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
    US

    831-460-4747 (voice)
    831-427-4748 (FAX)
    pcmsc_data@usgs.gov

Why was the data set created?

Projections for future sea-level rise provide emergency responders and coastal planners with critical hazards information that can be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. These data are intended for policy makers, resource managers, science researchers, students, and the general public. These data can be used with geographic information systems or other software to identify and assess possible areas of vulnerability. These data are not intended to be used for navigation.

How was the data set created?

  1. From what previous works were the data drawn?
    recharge (source 1 of 3)
    Reitz, M., Sanford, W. E., Senay, G. B., and Cazenas, J., 2017, Annual estimates of recharge, quick-flow runoff, and evapotranspiration for the contiguous US using empirical regression equations: Journal of the American Water Resources Association, online.

    Online Links:

    Type_of_Source_Media: digital dataset
    Source_Contribution:
    Digital recharge data used for model input. Users are advised to read the published paper and metadata for this source dataset carefully.
    Zell K and Head model thickness (source 2 of 3)
    Zell, Wesley O., and Sanford, Ward E., 2020, Calibrated simulation of the long-term average surficial groundwater system and derived spatial distributions of its characteristics for the contiguous United States: Water Resources Research, online.

    Online Links:

    Type_of_Source_Media: digital dataset
    Source_Contribution:
    Digital hydraulic conductivity (K) and associated model thickness data used for model input. Users are advised to read the published paper and metadata for this source dataset carefully.
    DEM1 (source 3 of 3)
    Tyler, D.J., Cushing, W.M., Danielson, J.J., Poppenga, S., Beverly, S., and Shogib, R., 2022, Topobathymetric model of the coastal Carolinas and Georgia, 1851 to 2020: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: digital dataset
    Source_Contribution:
    Digital elevation data used for model input. Users are advised to read the metadata for this source dataset carefully.
  2. How were the data generated, processed, and modified?
    Date: 03-Aug-2021 (process 1 of 5)
    Built MODFLOW (MODFLOW-NWT-SWR1 v1.2.0; https://www.usgs.gov/software/modflow-nwt-newton-formulation-modflow-2005) groundwater models for the model domain.
    Date: 15-Sep-2021 (process 2 of 5)
    Ran MODFLOW models to obtain groundwater heads.
    Date: 18-Dec-2021 (process 3 of 5)
    Revised MODFLOW models to use original Zell and Sanford (2017) model thicknesses and revised merging sequence.
    Date: 05-Mar-2022 (process 4 of 5)
    Reran MODFLOW models with revised merging sequence to eliminate artifacts associated with first tiling data and then merging to State products.
    Date: 16-May-2023 (process 5 of 5)
    Edits were made to correct spelling in author name. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. (scochran@usgs.gov)
  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?
    Attribute values are model-derived groundwater heads for present-day and future sea-level rise conditions. The model uses parameters from calibrated and published groundwater models and is intended to show the general response of the shallow coastal water table to sea-level rise. Projected heads for future sea-level rise conditions cannot be validated against observations.
  2. How accurate are the geographic locations?
    Data are concurrent with topographic digital elevation model (DEM) locations.
  3. How accurate are the heights or depths?
    Model-derived head elevations are accurate within the limitations of the model. The model uses parameters from calibrated, published groundwater models, but limitations due to model resolution and uncertainty in model parameter values may significantly affect modeled head elevations. As a result, model results are intended to show only the general response of the shallow coastal water table to sea-level rise.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented. Users are advised to read the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    Data have undergone quality checks and meet standards.

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 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 and the University of Arkansas as the originators of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA
    USA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? Zip files (GWHazards_GWHead_statename_K*0p1.zip, GWHazards_GWHead_statename_K*1.zip, GWHazards_GWHead_statename_K*10.zip) contain groundwater head projections for all 8 SLR cases for the State and hydraulic conductivity (K) indicated. When unzipped, individual groundwater head files have filenames with the structure “GWHead_(St_abbrev)_Kzell(K#)_slr(SLR#)m_50m_head”, where St_abbrev is the abbreviated State name (NC, SC), K# is 0p1, 1, or 10, and SLR# is 0p00, 0p25, 0p50, 1p00, 1p50, 2p00, 2p50, or 3p00. The “p” in file names is being used in place of a decimal point. File sizes are in MB.
  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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: The .zip file (GWHazards_GWHead_NC_Kx0p1.zip) includes 8 GeoTIFF files for the North Carolina, K x 0.1 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 1007.2
      Network links: https://doi.org/10.5066/P9W91314
      Data format: The .zip file (GWHazards_GWHead_NC_Kx1.zip) includes 8 GeoTIFF files for the State of North Carolina, K x 1 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 1005.1
      Network links: https://doi.org/10.5066/P9W91314
      Data format: The .zip file (GWHazards_GWHead_NC_Kx10.zip) includes 8 GeoTIFF files for the State of North Carolina, K x 10 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 998.6
      Network links: https://doi.org/10.5066/P9W91314
      Data format: The .zip file (GWHazards_GWHead_SC_Kx0p1.zip) includes 8 GeoTIFF files for the State of South Carolina, K x 0.1 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 584.9
      Network links: https://doi.org/10.5066/P9W91314
      Data format: The .zip file (GWHazards_GWHead_SC_Kx1.zip) includes 8 GeoTIFF files for the State of South Carolina, K x 1 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 583.5
      Network links: https://doi.org/10.5066/P9W91314
      Data format: The .zip file (GWHazards_GWHead_SC_Kx10.zip) includes 8 GeoTIFF files for the State of South Carolina, K x 10 hydraulic conductivities, for SLRs of 0, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m. in format GeoTIFF (version ArcGIS 10.5) Features are GeoTIFF format and are projected in UTM Zone 17 coordinates, with horizontal datum WGS84 and vertical datum NAVD88. Size: 580.6
      Network links: https://doi.org/10.5066/P9W91314
    • Cost to order the data: none

Who wrote the metadata?

Dates:
Last modified: 16-May-2023
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

831-460-4747 (voice)
831-427-4748 (FAX)
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_P9W91314/GWHazards_GWHead_metadata.faq.html>
Generated by mp version 2.9.51 on Tue May 16 16:48:23 2023