Kate V. Ackerman Zafer Defne Neil K. Ganju 20260521 1.0 vector digital dataset (polygon) data release DOI:10.5066/P13IBTSL Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P13IBTSL https://www.sciencebase.gov/catalog/item/69ab415cb66b01cd2fd12701 Kate V. Ackerman Zafer Defne Neil K. Ganju 2026 1.0 vector digital data data release DOI:10.5066/P13IBTSL Reston, VA U.S. Geological Survey Suggested citation: Ackerman, K.V., Defne, Z., and Ganju, N.K., 2026, Geospatial characterization of Delaware Bay-facing New Jersey salt marshes: U.S. Geological Survey data release, https://doi.org/10.5066/P13IBTSL. https://doi.org/10.5066/P13IBTSL https://www.sciencebase.gov/catalog/item/69ab4009b66b01cd2fd126e0 This data release contains coastal wetland synthesis products for the Delaware Bay-facing New Jersey salt marshes. Metrics for resiliency, including the unvegetated to vegetated ratio (UVVR), marsh elevation, tidal range, and lifespan are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health. The U.S. Geological Survey has been expanding national assessment of coastal change hazards and forecast products to coastal wetlands with the intent of providing federal, state, and local managers with tools to estimate the vulnerability and ecosystem service potential of these wetlands. 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. This shapefile contains calculated mean elevation values for each marsh unit and its vegetated component. Analysis of marsh elevation is part of a comprehensive assessment to identify the factors and their weights in determining the vulnerability and resiliency of salt marshes. Elevation distribution in Delaware Bay-facing New Jersey salt marshes is given in terms of mean elevation of conceptual marsh units, as well as the vegetated portion of the marsh unit. The elevation data is based on the USGS 1-m DEM. 2026 publication date Complete None -75.564126 -74.798014 39.765378 38.964539 ISO 19115 Topic Category oceans inlandWaters environment elevation USGS Thesaurus geospatial datasets wetland ecosystems wetland functions coastal ecosystems coastal processes vegetation None salt marsh marsh health estuary elevation USGS Metadata Identifier USGS:69ab415cb66b01cd2fd12701 GNIS Delaware Bay State of New Jersey None United States Dennis Creek Wildlife Management Area Heislerville Wildlife Management Area Egg Island Fish and Wildlife Management Area Fortescue Wildlife Management Area Nantuxent Wildlife Management Area New Sweden Wildlife Management Area Dix Wildlife Management Area Mad Horse Creek Wildlife Management Area Abbotts Meadow Wildlife Management Area Supawna Wildlife Management Area Salem River Wildlife Management Area No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. The mean elevation for each marsh unit is 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. Kate Ackerman U.S. Geological Survey Geologist mailing address

384 Woods Hole Road

Woods Hole MA 02543 US 508-548-8700 x2331 508-457-2310 kackerman@usgs.gov https://www.sciencebase.gov/catalog/file/get/69ab415cb66b01cd2fd12701/?name=Elev_NJ_BAY_Browse.png&allowOpen=true Graphic that shows elevation of conceptual marsh units in Delaware Bay-facing New Jersey salt marshes. PNG Environment as of Metadata Creation: Microsoft Windows 11; Esri ArcGIS Pro (version 3.4.3) Marsh units and water and land boundaries inherit their horizontal accuracy from the accuracy of the source data, the conceptual marsh units, and their vertical accuracy from the elevation dataset (USGS 1-m DEM). Positive elevation indicates above sea level. Marsh units with extremely low elevation (smaller than the 0.2 percentile value), extremely high elevation (larger than the 99.8 percentile value) or areas less than 900 square meters were flagged in the dataset. The marsh polygons are bound to the borders of New Jersey's estuarine intertidal areas that include: 1) emergent wetlands, 2) scrub-shrub areas, 3) rooted vascular aquatic beds, 4) organic unconsolidated shores, and 5) channels of open water that are narrower than 10 meters. Occasionally, marsh units are retained in this dataset even though the imagery displayed extreme change (e.g., partially or completely converted to water) from the NWI wetland delineation (e.g., marsh units 14296, 14394). In a few locations, there may be areas that that are classified as unvegetated but are in fact very sparsely vegetated. A detailed on-the-ground analysis of a single site may result in a different interpretation of the wetland and marsh unit boundaries than those established through this analysis. Horizontal accuracy for the polygon boundaries is inherited from the source layer, the conceptual marsh units, and is considered to be +/- 6 meters. Because the elevation values are averaged over delineated polygons, vertical accuracy depends on both the horizontal accuracy of the NWI dataset and the vertical accuracy of the source elevation dataset (USGS 1-m DEM). The vertical accuracy is inherited from the source elevation dataset; it is reported to be less than or equal to 0.30 meters. No additional accuracy assessment of the vertical accuracy has been conducted. U.S. Geological Survey 2021 First raster digital dataset Reston, VA U.S. Geological Survey Downloaded 1-meter DEM. Projection was NAD 1983 UTM Zone 18N referenced to the North American Vertical Datum of 1988 (NAVD88). Download date was 7/3/2024. https://apps.nationalmap.gov/downloader/ Digital 20190313 20190423 ground condition USGS DEM Elevation dataset K.V. Ackerman Z. Defne N.K. Ganju 2026 1.0 vector digital dataset (polygon) data release DOI:10.5066/P13IBTSL Reston, VA U.S. Geological Survey This dataset (Conceptual marsh units of Delaware Bay-facing New Jersey salt marshes) is within the larger data release (Geospatial characterization of Delaware Bay-facing New Jersey salt marshes). The first link below is to the conceptual marsh units data and the second link is to the data release. https://www.sciencebase.gov/catalog/item/671933b3d34e23541cc171c8 https://doi.org/10.5066/P13IBTSL Digital 2026 publication date CMU_NJ_Bay Used conceptual marsh units, generated as part of this data release, to delineate marsh unit boundaries. This process step and all subsequent process steps were performed by the same person, Kate Ackerman, in ArcGIS Pro (ver. 3.4.3), unless otherwise stated. For simple operations the name of the geoprocessing tool used is given in capital letters; for complex operations, the name of the geoprocessing tool used is given in capital letters and any critical parameters used are given in parentheses, separated by a semicolon, immediately after the tool name. The input and output file names are provided in [square brackets] when necessary. Units for length and area calculations are meters (m) and square meters unless otherwise stated. a) Set the data frame coordinate system and projection to NAD 1983 UTM Zone 18N. b) Establish marsh unit boundaries. Dissolve the vegetated and unvegetated classes in each marsh unit to have only one class for each marsh unit. DISSOLVE (Input features=[CMU_NJ_Bay.shp]; Dissolve field=FID_CMU; Statistics field=ATOT_M2 and FLG with Statistics type= First). PROJECT (Input coordinate system=WGS 1984 Web Mercator Auxiliary Sphere; Output coordinate system=NAD 1983 UTM Zone 18N) the feature dataset to obtain dissolved marsh units [mu_diss.shp]. c) Prepare elevation dataset. Combine all downloaded tiles into one raster, using MOSAIC TO NEW RASTER, and PROJECT RASTER to NAD 1983 UTM Zone 18N. d) Create a polygon that covers the area of interest [extent.shp]. CLIP the mosaicked elevation dataset created in step (c) by [extent.shp] to create [elev_mosaic.tif]. USGS DEM CMU_NJ_Bay 2025 elev_mosaic.tif mu_diss.shp Kate Ackerman U.S. Geological Survey Geologist mailing address

384 Woods Hole Road

Woods Hole MA 02543 US 508-548-8700 x2331 508-457-2310 kackerman@usgs.gov a) Remove pixels from elevation raster that are hydro-flattened. Use FOCAL STATISTICS (Input raster=[elev_mosaic.tif], Output raster=[FocalStats_3x3_range.tif], Neighborhood settings=3x3 cell, Statistics type=range) and RASTER CALCULATOR to identify (Map algebra expression: Con("%FocalStats_3x3_range.tif%" == 0,-1,1); Output raster=[elev_mosaic_One_NegOne.tif]) and remove (Map algebra expression: SetNull("%elev_mosaic_One_NegOne.tif%", "%elev_mosaic.tif%", "value = -1"); Output raster=[elev_mosaic_noHF.tif]) all hydro-flattened areas from [elev_mosaic.tif] to create [elev_mosaic_noHF.tif]. b) Calculate the mean elevation for each marsh unit with ZONAL STATISTICS AS TABLE (Feature zone data=[mu_diss.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_noHF.tif]; Statistics type=Mean; Output table=[mu]; Ignore Nodata=True). JOIN mean elevation from [mu] table to marsh units layer [mu_diss.shp] based on the "FID_CMU" field. Export dataset as a shapefile [mu_elev.shp]. Rename "mu_MEAN" to "MU_ELEV." c) Calculate the percent of the marsh unit that has hydro-flattened area. ZONAL STATISTICS AS TABLE (Feature zone data=[mu_elev.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_One_NegOne.tif]; Statistics type=Mean; Output table=[zs_muelev_HF]; Ignore Nodata=True). ADD FIELD to the output table to calculate hydro-flattened area of each marsh unit (MU_HFAR), CALCULATE FIELD (MU_HFAR= (1-MEAN)/2). JOIN MU_HFAR field to [mu_elev.shp]. If the percent hydro-flattened area is greater than 25 percent, set the marsh unit elevation to -9999. d) Calculate the elevation of the vegetated area of the marsh unit. SELECT BY ATTRIBUTES from [CMU_NJ_Bay.shp] where "TYP"= 'vegetated', output: [CMU_NJ_Bay_VEG.shp]. ZONAL STATISTICS AS TABLE (Feature zone data=[CMU_NJ_Bay_VEG.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_noHF.tif]; Statistics type=Mean; Output table=[vg]; Ignore Nodata=True). Join the mean elevation of the vegetated portion to [mu_elev.shp] and rename the field to "VG_ELEV." e) Calculate the percent of the vegetated portion of the marsh unit that has hydro-flattened area. ZONAL STATISTICS AS TABLE (Feature zone data=[CMU_NJ_Bay_VEG.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_One_NegOne.tif]; Statistics type=Mean; Output table=[zs_muelev_HF]; Ignore Nodata=True). ADD FIELD (VG_HFAR) to output table, CALCULATE FIELD (VG_HFAR= (1-MEAN)/2). Join VG_HFAR field to [mu_elev.shp]. If the percent hydro-flattened area is greater than 25 percent, set the vegetated elevation to -9999. f) JOIN the vegetated area (AVEG_M2) from [CMU_NJ_Bay_VEG.shp] to [mu_elev.shp]. elev_mosaic.tif 2025 mu_elev.shp a) Run Python script (marsv5.py) in ArcGIS Pro (v.3.4.3) to calculate metrics that quantify the distribution of marsh unit elevation values. Skewness ("SKWNSS") is the measure of asymmetry of the elevation distribution in the vegetated part of a marsh unit. Positive skewness values, i.e. right-skewed distributions, indicate clustering of elevation distributions towards lower elevations. Negative skewness values indicate a left-skewed distribution and clustering towards higher elevations. Lower third ("LOW3RD") is the percent of elevation values that fall within the lowest third of the elevation range within the vegetated part of a marsh unit. SKWNSS and LOW3RD parameters are calculated by applying the formulation of Raposa et al. (2016) to the elevation raster within the vegetated part of each marsh unit. JOIN these values to [mu_elev.shp]. If VG_ELEV= -9999, set SKWNESS and LOW3RD values to -9999. Export to a new shapefile [mu_elev_NJ_Bay.shp]. Reference: Raposa, K. B., Wasson, K., Smith, E., Crooks, J. A., Delgado, P., Fernald, S. H., et al. (2016). Assessing tidal marsh resilience to sea-level rise at broad geographic scales with multi-metric indices. Biological Conservation, 204, 263–275. https://doi.org/10.1016/J.BIOCON.2016.10.015. mu_elev.shp 2025 mu_elev_NJ_Bay.shp a) Add field "FLG" to flag anomalous marsh units based on absence of vegetation, elevation, surface area, and tidal range extrapolation. The flags are calculated in their respective shapefile (i.e., elevation flags are calculated in the elevation shapefile). Set FLG to: (-1) no vegetated area in the marsh unit; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than the 0.2 percentile; (-200) greater than 25 percent of the marsh unit elevation is hydro-flattened; (-1000) marsh unit surface area less than 900 square meters; (-10000) mean tidal range of marsh unit is extrapolated; and (0) no flag. Combination of negative values indicates a combination of flags; for example, -1001 indicates no vegetated area and area less than 900 square meters. b) Rearrange fields and change the projection for better performance of web services with online base maps. PROJECT (Output coordinate system=WGS 1984 Web Mercator Auxiliary Sphere) the feature dataset to obtain the final elevation dataset [mu_elev_NJ_Bay.shp]. 2025 mu_elev_NJ_Bay.shp Vector G-polygon 7368 WGS 1984 Web Mercator Auxiliary Sphere (Esri full name: WGS_1984_Web_Mercator_Auxiliary_Sphere) 0.0 0.0 0.0 0.0 coordinate pair 0.6096 0.6096 meters D_WGS_1984 WGS 84 6378137.0 298.257223563 mu_elev_NJ_Bay.shp Attribute Table Table containing attribute information associated with the dataset. USGS FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Feature geometry. Marsh units are polygon features. FID_CMU Unique whole numbers used to identify each conceptual marsh unit. These FID_CMU values begin at a value that is one greater than the ending FID_CMU value in the Atlantic-facing New Jersey salt marshes dataset so that the datasets can be combined, if desired. USGS 10512 17879 none ATOT_M2 Total surface area of a marsh unit in square meters. USGS 18.31969 2104231.06995 square meters AVEG_M2 Surface area of the vegetated part of a marsh unit in square meters. USGS 0.0 1661070.64984 square meters MU_ELEV Mean elevation of a marsh unit. If the percent hydro-flattened area is greater than 25 percent (MU_HFAR is greater than 0.25), the marsh unit elevation is set to -9999 indicating insufficient elevation data. USGS -0.98244 3.47962 meters VG_ELEV Mean elevation of the vegetated area in a marsh unit. If there is no vegetated area in the marsh unit, the value is set to -9999. Also, if the percent hydro-flattened area in the vegetated portion is greater than 25 percent (VG_HFAR is greater than 0.25), the value is set to -9999 indicating insufficient elevation data. USGS -0.98252 3.49343 meters MU_HFAR Percent (in decimal form) of the marsh unit that contains hydro-flattened bathymetric/elevation values. USGS 0 1 none VG_HFAR Percent (in decimal form) of the vegetated portion of the marsh unit that contains hydro-flattened bathymetric/elevation values. If there is no vegetated area in the marsh unit, the value is set to -9999. USGS 0 1 none SKWNSS The measure of skewness of the elevation distribution in the vegetated part of a marsh unit. Positive skewness values (i.e., right-skewed distribution) indicate clustering of elevation distribution towards lower elevations. Negative values (left-skewed distribution) indicate clustering towards higher elevations. A value of -9999 indicates no vegetated area within the marsh unit or no elevation value for the vegetated portion. USGS -6.66418 8.90081 none LOW3RD LOW3RD is the percent of elevation values that fall within the lowest third of the elevation range within the vegetated part of a marsh unit. Value of -9999 indicates no vegetated area within the marsh unit or no elevation value for the vegetated portion. USGS 0.007764 99.85919 none FLG Marsh unit flag indicating anomalous marsh units based on absence of vegetation, elevation, surface area and tidal range extrapolation. FLG values indicate: (-1) no vegetated area in the marsh unit; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than the 0.2 percentile; (-200) greater than 25 percent of the marsh unit elevation is hydro-flattened; (-1000) marsh unit surface area less than 900 square meters; (-10000) mean tidal range of marsh unit is extrapolated; and (0) no flag. Combination of negative values indicates a combination of flags. For example, -1001 indicates no vegetated area and area less than 900 square meters. USGS -11200 0 none In this dataset, mean elevation for each conceptual salt marsh unit in the Delaware Bay-facing New Jersey salt marshes has been calculated based on the USGS 1-m DEM source datasets. 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 area and elevation values is assumed to be 1 meter and 0.01 meter, respectively. USGS U.S. Geological Survey - ScienceBase mailing and physical address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov mu_elev_NJ_Bay.zip (ZIP file contains the shapefile mu_elev_NJ_Bay.shp and the additional shapefile components), browse graphic, and FGDC CSDGM metadata in xml format. 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 for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. 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. shapefile ArcGIS Pro 3.4.3 This dataset contains a polygon shapefile and its components and metadata in xml format. 57 https://www.sciencebase.gov/catalog/file/get/69ab415cb66b01cd2fd12701 https://www.sciencebase.gov/catalog/item/69ab415cb66b01cd2fd12701 https://doi.org/10.5066/P13IBTSL The first link in network resources is to download data directly. The second link points to a landing page with metadata and data. The third link is to the main page of the data release. None. No fees are applicable for obtaining the dataset. 20260521 Kate V. Ackerman U.S. Geological Survey Geologist mailing address

384 Woods Hole Rd

Woods Hole MA 02543 US 508-548-8700 x2331 508-457-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998