Inferred hydrodynamic residence time in salt marsh units in Edwin B. Forsythe National Wildlife Refuge, New Jersey

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Frequently anticipated questions:

What does this data set describe?

Title:
Inferred hydrodynamic residence time in salt marsh units in Edwin B. Forsythe National Wildlife Refuge, New Jersey
Abstract:
As part of the Hurricane Sandy Science Plan, the U.S. Geological Survey is expanding National Assessment of Coastal Change Hazards and forecast products to coastal wetlands. The intent is to provide federal, state, and local managers with tools to estimate the vulnerability of coastal wetlands to various factors and to evaluate their ecosystem service potential. For this purpose, the response and resilience of coastal wetlands to physical factors need to be assessed in terms of the ensuing change to their vulnerability and ecosystem services. Edwin B. Forsythe National Wildlife Refuge (EBFNWR), New Jersey, was selected as a pilot study area.
As part of this data synthesis effort, hydrodynamic and sediment transport modeling of Barnegat Bay Little Egg Harbor (BBLEH) has been used to create the following wetland data layers in Edwin B. Forsythe National Wildlife Refuge (EBFNWR), New Jersey: 1) Hydrodynamic residence time , 2) salinity change and 3) salinity exposure change in wetlands, and 4) sediment supply to wetlands. The residence time layer was based on the hydrodynamic and particle tracking modeling of the period 3/1/2012 to 5/1/2012 by Defne and Ganju (2015). For this data layer, the residence time map of estuarine water has been projected over the EBFNWR salt marshes. The rest of the layers were derived from the BBLEH hydrodynamic modeling for the Hurricane Sandy period that spans from 10/27/2012 to 11/04/2012 (Defne and Ganju, 2016a). The model estimated changes in salinity and sediment concentrations over the salt marshes caused by storm-induced coastal flooding. The results are summarized over the previously determined conceptual salt marsh unit polygons (Defne and Ganju, 2016b).
  1. How might this data set be cited?
    Defne, Zafer, and Ganju, Neil K., 2017, Inferred hydrodynamic residence time in salt marsh units in Edwin B. Forsythe National Wildlife Refuge, New Jersey: data release DOI:10.5066/F7K64GZT, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Defne, Zafer, and Ganju, Neil K., 2017, Wetland data layers derived from Barnegat Bay Little Egg Harbor hydrodynamic model: data release DOI:10.5066/F7K64GZT, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Defne, Zafer, Ganju, N.K., 2017, Wetland data layers derived from Barnegat Bay Little Egg Harbor hydrodynamic model: U.S. Geological Survey data release, https://doi.org/10.5066/F7K64GZT
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -74.484623118
    East_Bounding_Coordinate: -74.051158122
    North_Bounding_Coordinate: 40.053798801
    South_Bounding_Coordinate: 39.435117592
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/59655120e4b0d1f9f05b367a?name=mu_RTS_EBFNWRp.png (PNG)
    Graphic that shows the inferred hydrodynamic residence time in the EBFNWR salt marsh complex overlaying Esri Shaded World Relief Map.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2017
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (1338)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 Web Mercator Auxiliary Sphere (ESRI Full Name: WGS_1984_Web_Mercator_Auxiliary_Sphere).
      Projection parameters:
      Standard_Parallel: 0.0
      Longitude_of_Central_Meridian: 0.0
      False_Easting: 0.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in Meter
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    mu_RTS_EBFNWRp
    Attribute information associated with the hydrodynamic residence time in the conceptual marsh units of EBFNWR salt marsh complex. (Source: USGS)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    FID_CMU
    Sequential unique whole numbers that represents the identification number for each conceptual marsh units. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1337
    MEAN
    Bay water residence time estimated over each marsh unit (Source: USGS)
    Range of values
    Minimum:0.032182
    Maximum:50.6268
    Units:days
    Entity_and_Attribute_Overview:
    In this dataset, hydrodynamic residence time in BBLEH projected and averaged over each conceptual marsh unit in EBFNWR. A higher residence time indicates longer time required to exchange between the bay water surrounding the marsh unit and the open ocean. The inferred residence times in this dataset are not the actual residence times for water in the marsh units. Inferred residence time should be considered as a geospatially varying indicator of relative flushing time scales for the marsh units with respect to each other. Decimal values in the attribute table are a result of double precision calculations while significant digits are considered in defining the attribute measurement resolutions. Therefore, the smallest unit increment for inferred residence time values can be assumed to be a practical value such as 0.01 days.
    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)
    • 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: Zafer Defne
    Ocean Scientist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2254 (voice)
    508-457-2310 (FAX)
    zdefne@usgs.gov

Why was the data set created?

This polygon dataset facilitates quantifying vulnerability to contaminant hazards in the EBFNWR salt marsh complex by looking at the residence time of water within the complex. The results are summarized over the previously determined conceptual salt marsh unit polygons (Defne and Ganju, 2016b). Analysis of hydrodynamic residence time is part of a comprehensive assessment to identify the factors and their weights in determining the vulnerability and resiliency of salt marshes. Residence time is inferred from the residence time calculations in the Barnegat Bay - Little Egg Harbor (BBLEH) estuary based on the hydrodynamic and particle tracking modeling by Defne and Ganju (2015).

How was the data set created?

  1. From what previous works were the data drawn?
    marshUnitsEBFp.shp (source 1 of 2)
    Defne, Zafer, and Ganju, Neil K., 2016, Conceptual salt marsh units for wetland synthesis: Edwin B. Forsythe National Wildlife Refuge, New Jersey: data release DOI:10.5066/F7QV3JPG, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    Downloaded and used the features in [marshUnitsEBFp.shp] to infer hydrodynamic residence times at each marsh unit
    MN_EBFNWRp.tif (source 2 of 2)
    Defne, Zafer, and Ganju, Neil K., 2016, Raster image of mean tidal range in the Edwin B. Forsythe National Wildlife Refuge, New Jersey (32-bit GeoTIFF): data release DOI:10.5066/F7CF9N7X, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    Downloaded used this raster to estimate the residence time values outside of the BBLEH computational domain.
  2. How were the data generated, processed, and modified?
    Date: 2017 (process 1 of 8)
    This process step used ArcMap (ver. 10.3.1) using tools from ArcToolbox. Names of specific tools used are given in CAPITAL letters (any critical parameters used is given in parentheses, separated by a semicolon, immediately after the tool name). Input 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.
    Defne and Ganju (2015) modeled estuarine circulation in BBLEH during March-May 2012 with a three-dimensional hydrodynamic model. The computational domain included a part of Great Bay to the south and Manasquan Inlet to the north in addition to Barnegat Bay and Little Egg Harbor. Neutrally buoyant, passive numerical particles that represent water parcels were released uniformly within the estuary and tracked until their first exit. The time elapsed for a particle to leave the estuary was assigned as a residence time to the initial release location of that particle to create a spatially varying residence time map. The residence time map of the estuary has been projected over the surrounding salt marshes with an inverse distance weighted interpolation method in the present study.
    Import computational modeling output and project to UTM coordinate system.
    a) MAKE XY EVENT LAYER('XY table'= 'resTimeSpring.txt'; X field='lon'; Y field='lat'; Z field='val'; Layer name='resTimeSpring.shp'; Spatial reference='GCS_WGS_1984')
    b) PROJECT(Input dataset='resTimeSpring.shp'; Output dataset='resTimeSpring_UTM.shp'; Output coordinate system='NAD_1983_UTM_Zone_18N')
    No datum transformation was applied. For the puposes of this work, the two datums are considered the same. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Zafer Defne
    Ocean Scientist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2254 (voice)
    508-457-2310 (FAX)
    zdefne@usgs.gov
    Data sources produced in this process:
    • resTimeSpring_UTM.shp
    Date: 2017 (process 2 of 8)
    Part of the EBFNWR salt marsh system to south of the Little Egg inlet is not covered by the particle modeling used to estimate the hydrodynamic residence time. Given the similar geospatial trend between the mean tidal range and the residence time, mean tidal range data layer is used calculate the residence time in the area without adequate coverage. The mean tidal range data from a region to the north of the Little Egg Inlet, which is approximately the same distance from the southern boundary of the marsh system is used for a regression analysis between the two parameters. First, marsh units that are inside and are outside of the BBLEH computational domain are determined.
    a) Select features from [marshUnitsEBFp.shp] marsh polygons that are within the BBLEH computational domain and export as [mu_with_data.shp].
    b) Invert selection and export polygons outside the computational domain as [mu_no_data.shp]. Data sources used in this process:
    • marshUnitsEBFp.shp
    Data sources produced in this process:
    • mu_with_data.shp
    • mu_no_data.shp
    Date: 2017 (process 3 of 8)
    Define the area and the corresponding hydrodynamic residence time and mean tidal range values to be used For regression analysis.
    a) Define the area for regression analysis. Create a clipping polygon [RTS_band.shp] defining the region to be used for analysis with the following longitude and latitude pairs: Lon=[-74.21948353, -74.29906237, -74.30960359, -74.23233313] degrees, Lat=[39.59353924, 39.50480988, 39.51032439, 39.60009922].
    b) Define the values of residence time to be used. Calculate across-the-bay averages from the particle tracking model output in Matlab [res_time_run071tRXspring_xAVG.txt].
    c) MAKE XY EVENT LAYER('XY table'= 'res_time_run071tRXspring_xAVG.txt'; X field='lon'; Y field='lat'; Z field='val'; Layer name='RTS_xAVG.shp'; Spatial reference='GCS_WGS_1984')
    d) IDW.SpatialAnalyst(Input feature='RTS_xAVG.shp'; Output Cell Size=0.001 degrees; Power=2; Search Radius=Variable; Number of Points=12; Output raster='RTS_xAVG_idw.tif')
    e) Crop the residence time data with the clipping polygon defined in step (a). EXTRACT BY MASK(Input raster='RTS_xAVG_idw.tif'; Input mask data='RTS_band.shp') to obtain [RTS_idw_clip.tif].
    f) Crop the mean tidal range raster to the same clipping polygon while updating the raster properties. EXTRACT BY MASK(Input raster='MN_EBFNWRp.tif'; Input mask data='RTS_band.shp') to obtain [MN_idw_clip.tif] and set the following environment settings same as [RTS_xAVG_idw.tif]: Processing extent, Snap raster, Raster analysis cell size.
    g) RASTER TO POINT with [MN_idw_clip.tif], [RTS_xAVG_idw.tif] to obtain [MN_idw_pts2.shp] and [RTS_idw_pts2.shp], respectively. Data sources used in this process:
    • MN_EBFNWRp.tif
    Data sources produced in this process:
    • RTS_idw_pts2.shp
    • MN_idw_pts2.shp
    Date: 2017 (process 4 of 8)
    Export extracted point features in the previous step as tables using XTools Pro and perform regression analysis using Matlab. Regression analysis of 1507 points results in the best fit curve given with the equation y=613.3284*exp(-((x + 0.4271)^2)/(2*0.3709^2)), where x is mean tidal range in meters and y is hydrodynamic residence time in days. Pearson correlation coefficient for the fit is 0.95. Data sources used in this process:
    • RTS_idw_pts2.shp
    • MN_idw_pts2.shp
    Date: 2017 (process 5 of 8)
    Create a raster layer from point features and project to Web Mercator coordinate system, which is preferred projection for web services.
    a) IDW.SpatialAnalyst(Input feature='resTimeSpring_UTM.shp'; Output Cell Size=30 meters; Power=2; Search Radius=Variable; Number of Points=12; Output raster='RTS_idw_UTM.tif').
    b) PROJECT(Input dataset='RTS_idw_UTM.tif'; Output dataset='RTS_idw_webm.tif'; Output coordinate system='WGS_1984_Web_Mercator_Auxiliary_Sphere') with the Raster processing extent same as the extent of the marsh unit polygons [marshUnitsEBFp.shp]. During this process the area outside of the BBLEH computational domain gets assigned "NoData" for residence time. Data sources used in this process:
    • resTimeSpring_UTM.shp
    Data sources produced in this process:
    • RTS_idw_webm.tif
    Date: 2017 (process 6 of 8)
    Extract the mean tidal range values to be used with the best fit equation to estimate the mean residence time. Apply the equation to calculate residence time estimates.
    a) EXTRACT BY MASK from mean tidal range dataset [MN_EBFNWRp.tif] using [mu_no_data.shp] to obtain [MN_EBFNWRp_nodata.tif].
    b) Apply the equation with RASTER CALCULATOR(Map algebra expression=Con(IsNull("RTS_idw_webm.tif"), 613.3284*Exp(-(("MN_EBFNWRp_nodata.tif" + 0.4271)**2)/(2*0.3709**2)),"RTS__idw_webm.tif"); Output raster='RTS_EBFNWRp.tif'). This expression replaces the "NoData" values outside the BBLEH computational domain with the estimated values. Data sources used in this process:
    • MN_EBFNWRp.tif
    Data sources produced in this process:
    • RTS_EBFNWRp.tif
    Date: 2017 (process 7 of 8)
    Calculate the residence time values for marsh units using the zonalTable2Feat tool. This tool calculates the statistics (e.g. the mean value) for each marsh unit polygon [marshUnitsEBFp.shp] from the underlying raster layer [RTS_EBFNWRp.tif] to obtain the final feature dataset [mu_RTS_EBFNWRp.shp]. Fields and field names of the final feature dataset are edited for clarity. Data sources used in this process:
    • RTS_EBFNWRp.tif
    • marshUnitsEBFp.shp
    Data sources produced in this process:
    • mu_RTS_EBFNWRp.shp
    Date: 07-Aug-2020 (process 8 of 8)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Defne, Zafer, and Ganju, Neil K., 2016, Conceptual salt marsh units for wetland synthesis: Edwin B. Forsythe National Wildlife Refuge, New Jersey: data release DOI:10.5066/F7QV3JPG, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Defne, Zafer, and Ganju, Neil K., 2016, Storm-induced geomorphological changes in a shallow, back-barrier estuary.

    Online Links:

    Other_Citation_Details:
    American Geophysical Union Ocean Sciences Meeting, New Orleans, LA, USA
    Defne, Zafer, and Ganju, Neil K., 2015, Quantifying the residence time and flushing characteristics of a shallow, back-barrier estuary: application of hydrodynamic and particle tracking models: Estuaries and Coasts Volume 38, Springer US, New York, NY.

    Online Links:

    Other_Citation_Details: pages 1719-1734

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

  1. How well have the observations been checked?
    Water-land boundary and marsh unit boundaries inherit from accuracy of source data, conceptual marsh units. Inferred residence time layer is calculated by resampling the bay water residence time at a higher horizontal resolution of 0.0003 degrees (~30 meters) prior to averaging over each marsh unit.
  2. How accurate are the geographic locations?
    Horizontal accuracy for the polygon boundaries is inherited from the source layer, conceptual marsh units, and considered to be greater than ~3 meters. The point cloud used for calculating residence time had variable horizontal resolution (~40 to ~300 meters) that was interpolated over a ~30-meter raster. The raster dataset was resampled at 3 meter resolution to enhance the conformity with the marsh unit boundaries prior to calculating zonal statistics.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    The polygon outlines for this dataset are defined by the conceptual marsh unit boundaries in the source dataset. That is the boundaries of the EBFNWR areas that include unvegetated and vegetated areas. A detailed on-the-ground analysis of a single site may result in a different interpretation of the wetland and marsh unit boundaries than established through this analysis.
  5. How consistent are the relationships among the observations, including topology?
    By definition residence time cannot be a negative real number. Final values for each marsh unit were verified to be a positive real number.

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:
The inferred residence times in this dataset 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 - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? mu_RTS_EBFNWRp.zip contains mu_RTS_EBFNWRp.shp (together with shapefile components, browse graphic, and associated FGDC CSDGM metadata in XML, TEXT, and HTML formats with the same prefix file name).
  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: 07-Aug-2020
Metadata author:
U.S. Geological Survey
Attn: Zafer Defne
Ocean Scientist
384 Woods Hole Road
Woods Hole, MA

508-548-8700 x2254 (voice)
508-457-2310 (FAX)
zdefne@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_F7K64GZT/mu_RTS_EBFNWRp.shp.faq.html>
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