Joseph F. Terrano Jonathan Pitchford Michael Archer Kathryn E.L. Smith 20250527 1.0 tabular digital data Joseph F. Terrano Alisha M. Ellis Kathryn E.L. Smith Jonathan Pitchford Michael Archer Joseph M. Vargas Jonathan P. Griffiths Samuel M. Randall Matthew Virden Cheyenne S. Everhart Eric Sparks 20250527 1.0 Multimedia presentation U.S. Geological Survey data release doi:10.5066/P13VT3ET St. Petersburg, FL U.S. Geological Survey https://doi.org/10.5066/P13VT3ET To better understand sediment deposition in marsh environments, scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center (USGS-SPCMSC) selected five marsh study sites (Sites 5, 6, 7, 8, and 9) and four nearshore estuarine study sites (Sites 8S, 8D, 9S, 9D) along the Point Aux Chenes Bay shoreline of the Grand Bay National Estuarine Research Reserve (GNDNERR), Mississippi. This study builds on Smith and others (2020b) and includes datasets collected after the installation of a living shoreline (a subtidal sill [artificial reef]) that was completed in May 2021. Each marsh site consisted of five plots located along a transect perpendicular to the marsh-estuary shoreline at 5-meter (m) increments (5, 10, 15, 20, and 25 m from the shoreline). Each plot contained three to six net sedimentation tiles (NST) that were secured flush to the marsh surface using polyvinyl chloride (PVC) pipe. NST are an inexpensive and simple tool to assess short- and long-term deposition that can be deployed in highly dynamic environments without the compaction associated with traditional coring methods. The NST were deployed for three-month sampling periods, measuring sediment deposition from August 2021 to January 2023. Sediment deposited on the NST were processed to determine physical characteristics, such as deposition thickness, volume, wet weight/dry weight, grain size, and organic content (via loss-on-ignition [LOI]). For select sampling periods, ancillary data (water level, elevation, and vegetation) are also provided in this data release. The estuarine sites consisted of Site 8S (shallow; landward of the subtidal sill), 8D (deep; seaward side of the subtidal sill), as well as 9S and 9D (both sites established adjacent to 8S/8D and the subtidal sill). During select trips water parameters (e.g., waves, water level, and turbidity) were collected at each estuarine site to collect turbidity and wave data. Data presented in this data release were collected under three USGS Field Activities Numbers (FAN; one FAN per year) during thirteen sampling trips (alternate FAN; each sampling trip was assigned a unique alt FAN under the main FAN): 2021-320-FA (21CCT01, 21CCT03, 21CCT04, 21CCT05), 2022-302-FA (22CCT01, 22CCT02, 22CCT03, 22CCT04, 22CCT05, 22CCT06, 22CCT07, 22CCT08) and 2023-301-FA (23CCT01), however, every trip does not contain all data types. This data release also contains data for 2020-323-FA (20CCT02) that was collected as a special collection trip for Hurricane Delta. This data was collected before the subtidal sill was installed and is being published with this data release since pre-subtidal sill data was already published. Additional survey and data details are available from the U.S. Geological Survey Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/. Users can look up USGS FANs in the CMGDS by replacing the FAN in the following url: https://cmgds.marine.usgs.gov/services/activity.php?fan=2022-302-FA. Data from a related NST study in the GNDNERR (Middle Bay and North Rigolets) can be found in Smith and others (2020a). Data collected from before the living shoreline (subtidal sill) installation can be found in Smith and others (2020b). For additional information on data processing and analysis, refer to the accompanying journal publication Smith and others (2025). Please read the full metadata for details on data collection, dataset variables, and data quality. Vegetation species and abundance data can provide important information on the health of a marsh. Vegetation surveys were conducted within each NST plot (1 square meter). Within each plot the average vegetation canopy height was measured, a percent cover for each species was estimated, and a sub-sampled stem count of each species from 1/16th of a meter of the plot was collected. Data was collected through three field visits. Each field visit was assigned a field activity number (FAN) and alternate FAN (alt-FAN) by the U.S Geological Survey (USGS). Vegetation data was only collected during field activities from: 1) 2021-320-FA (21CCT01, August 2021), 2) 2022-302-FA (22CCT03, May 2022 and 22CCT08, December 2022). 20210818 20221219 ground condition Complete As needed -88.4474 -88.4435 30.3370 30.3337 USGS Metadata Identifier USGS:a2f750c2-dfa7-4abc-8705-10afb650154e ISO 19115 Topic Category environment oceans geoscientificinformation USGS Thesaurus unconsolidated deposits geology geomorphology coastal processes wetland ecosystems plot sampling land use and land cover vegetation None sediment net sedimentation tile NST sediment plate physical parameters U.S. Geological Survey USGS U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center SPCMSC deposition marsh None Grand Bay National Estuarine Research Reserve NERR Geographic Names Information System State of Mississippi Point Aux Chenes None sediment surface No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Common 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. U.S. Geological Survey - St Petersburg Coastal and Marine Science Center Joseph F. Terrano Physical Scientist Mailing

600 4th Street South

St. Petersburg FL 33701 727-502-8047 727-502-8182 jterrano@usgs.gov The authors would like to acknowledge the GNDNERR staff for their contributions in collecting and reviewing this data. Environment as of Metadata Creation: Microsoft Windows 10 Enterprise Version 22H2 (Build 19045.3324, Windows Feature Experience Pack 1000.19041.1000.0); Microsoft Excel for Microsoft 365 MSO (Version 2302, Build 16.0.16130.20806, 32-bit) Kathryn E.L. Smith Joseph F. Terrano Nicole S. Khan Chelsea A. Stalk 20200226 St. Petersburg, Florida United States Geological Survey Smith and others (2020a) https://doi.org/10.5066/P9BFR2US Kathryn E.L. Smith Joseph F. Terrano Jonathan Pitchford Michael Brochard Joseph M. Vargas Isabelle D. Atchia Cheyenne S. Everhart Christopher G. Smith 20200713 2.0 (June 2023) St. Petersburg, Florida United States Geological Survey-St. Petersburg Coastal and Marine Science Center Smith and others (2020a) https://doi.org/10.5066/P9ONI8PS Kenneth Moore 20091201 Gloucester Point, Virginia Chesapeake Bay National Estuarine Research Reserve System in Virginia https://coast.noaa.gov/data/docs/nerrs/Research_TechSeries_TechReportSWMPBio-MonitoringProtocol.pdf Kathryn E.L. Smith Jonathan L. Pitchford Eric L. Sparks Michael J. Archer Matthew F. Virden Joseph F. Terrano Christopher G. Smith 20250612 Estuaries and Coasts Volume 48, Article 128 Online Springer Nature Smith and others (2025) https://doi.org/10.1007/s12237-025-01564-7 Vegetation data was collected by the Grand Bay National Estuarine Research Reserve and provided to the USGS as a comma separated value (CSV) file. Elevation, positional information, and positional accuracy can be found in the "GB_Elevation_Data_2020_2023" folder of this data release. The data included in this data file are related to: FAN, alternate FAN, site, plot distance, plot canopy height, vegetation species, percent cover, and stem counts. Additional attribute information and definitions are provided below. Comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies in data collection methods. This is a complete, vegetation survey data file for data collected within the Grand Bay National Estuarine Research Reserve, Mississippi from August 2021 to December 2022. Canopy height is considered the average of all vegetation species for the plot, thus only one value is presented per plot, and all remaining cells are intentionally left blank. Stem counts with blank cells denote no stems of that species were counted in the subsampled plot, however, that vegetation type is present in the overall plot. Five previously established study sites (Sites 5, 6, 7, 8, and 9) containing net sedimentation tiles (NST) within the Grand Bay National Estuarine Research Reserve, Mississippi were used to collect vegetation data. NST plots (a 1 square meter plot) were located at 5, 10, 15, 20 and 25 m inland and perpendicular to the shoreline. Vegetation surveys were conducted by Grand Bay National Estuarine Research Reserve staff in 21CCT01 (August 2021), 22CCT03 (May 2022), and 22CCT08 (December 2022) using NERR system wide monitoring protocols (Moore, 2009). First, a 1 square meter quadrat was placed on the corner PVC markers of the plot to ensure the quadrat covered the study area. To collect percent cover, the observer looked at the whole plot, then visualized that all of one species were gathered together and pushed to once side of the quadrat (if it appears that three-quarters of the quadrat is covered, then the percent cover for that species is 75%). This was repeated for each of the vegetation species, making sure that the overall sum of percent cover with species was not greater than 100%. To collect canopy height, a pole marked at 25-centimeter (cm) intervals was used to estimate the average height (in meters) of the vegetation within the plot. To collect stem densities, the quadrat was marked at 1/16th of a meter in the upper right corner. Within the smaller quadrat area, the number of stems for each species were counted. The field sheet data for each field activity was compiled and transferred to a CSV file for inclusion in this data release. 2023 Grand_Bay_Vegetation_2021_2022.csv Grand Bay National Estuarine Research Reserve Jonathan Pitchford Stewardship Coordinator Mailing and physical

6005 Bayou Heron Road

Moss Point MS 39562 U.S. (228) 523-4009 jonathan.pitchford@dmr.ms.gov Grand_Bay_Vegetation_2021_2022.csv Vegetation data collected from NST plots located in the marsh at Grand Bay National Estuarine Research Reserve, Mississippi, from August 2021, May 2022, and December 2022. Blanks indicate no data. USGS FAN USGS field activity number (FAN) assigned to each sample collection trip. USGS Field activity numbers were assigned by the USGS to track field collection of samples. The FAN consists of YYYY-XXX-FA, with YYYY being the 4-digit year, XXX being the trip number, and FA representing that it is a field activity. Alt_FAN Alternate (abbreviated) FAN assigned each collection trip. USGS FANs were assigned by the USGS and are YYCCTXX, where YY is the 2-digit year, CCT stands for coastal change and transport (a USGS project identifier), and XX is the trip number. Site Site number. USGS 5 9 Plot distance (meters) Distance inland to the NST plot from the shoreline. USGS 5 25 meters (m) Plot canopy* height (meters) *Canopy height is an average of all vegetation species for the plot. Only one value is presented per plot. USGS 0.10 1.25 meters (m) Vegetation species Scientific name (genus and species) of the vegetation in the vegetation plot. USGS Scientific name (genus and species) of the vegetation. Unknown was used if the species could not be identified. Some plots have multiple unknown species. Percent cover (%) Percent of the plot that was covered by each species. Combined percent of all species cannot exceed 100 percent. The difference between 100 percent and the sum of all species within the plot represents unvegetated area. USGS <5 70 percent (%) Stem count^ ^Stem count sub samples were collected from a marked area on the quadrat (at 1/16 of a meter) from the top right corner of each plot. Stem counts with blank cells denote no stems of that species were counted in the sub sampled plot however that vegetation type is present in the overall plot. USGS 1 35 U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov GB_Vegetation_Data_2021_2022.csv 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. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Comma-delimited text https://coastal.er.usgs.gov/data-release/doi-P13VT3ET/GB_Vegetation_Data_2021_2022.zip None 20250618 U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998