Emma S. Chestang Christopher G. Smith 20260422 tabular digital data Emma S. Chestang Christopher G. Smith Angela Knapp Kristen Buck Tim Conway Joseph J. Tamborski Hannah Hunt Dreux Chappell Rene Boiteau Andrew Lindgren Salvatore Caprara 20260422 U.S. Geological Survey data release doi:10.5066/P13X6MBL St. Petersburg, Florida U.S. Geological Survey https://doi.org/10.5066/P13X6MBL This dataset contains level, temperature, and conductivity data collected by scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) to investigate submarine groundwater discharge on the West Florida Shelf at sample sites located in three areas of Florida: Indian Rocks Beach (IRB), Nature Coast near Hudson (NC), and Venice Headlands near Venice (VH). These data were collected using Solinst LTC 5 (serial number starting with 108) and LTC Edge (serial number starting with 107) leveloggers deployed in offshore groundwater wells on the West Florida Shelf. The dataset is a time series of submarine groundwater discharge parameters including water temperature (degrees Celsius [°C]), pressure (centimeters of water [cmH2O]), and conductivity (millisiemens per centimeter [mS/cm]). Each parameter was measured every fifteen to twenty minutes (varies by logger) for 24-hour time periods throughout the duration of deployment. Data included in this data release correspond to USGS Field Activity Number (FAN) 2022-340-FA, with associated events spanning over one year (November 2022 to February 2024) and are distinguished by alternative FANs (altFANs) or events of 22WFS05, 23WFS01, 23WFS02, 23WFS03, 23WFS04, 24WFS01. This dataset was acquired to assist USGS staff with the quantification, analysis and interpretation of geochemical time series data that will ultimately be used in assessments and research of or related to submarine groundwater discharge. All sampling activities correspond to the USGS Field Activity Number 2022-340-FA. Additional survey and data details are available from the USGS Coastal and Marine Geoscience Data System (CMGDS) at https://cmgds.marine.usgs.gov/services/activity.php?fan=2022-340-FA. 20221115 20240307 ground condition Complete As needed -82.8779 -82.4648 28.3777 27.0895 USGS Metadata Identifier USGS:f3e01ad3-232f-44b6-83b9-414989b0733a ISO 19115 Topic Category geoscientificInformation environment oceans USGS Thesaurus geochemistry time series analysis marine geology water temperature salinity None conductivity pressure Geographic Names Information System (GNIS) State of Florida Gulf of America None Gulf of Mexico None seafloor None November 2022 January 2023 February 2023 May 2023 June 2023 September 2023 December 2023 February 2024 March 2024 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. Christopher G. Smith U.S. Geological Survey Research Geologist mailing and physical

600 4th Street South

St. Petersburg FL 33701 US 727-502-8035 cgsmith@usgs.gov The National Science Foundation (National Science Foundation Grant Award OCE-2148989, Project 880516) and USGS Coastal Marine Hazards and Resources Program (CMHRP) contributed funding and resources that enabled samples to be collected and analyzed. Environment as of Metadata Creation: Microsoft Windows 11 Enterprise Version 23H2; Microsoft Excel Version 2402; Solinst Levelogger Software 5. Chestang, E.S., Ellis, A.M., Smith, C.G., Knapp, A., Tamborski, J.J., and Lindgren, A. 20250813 U.S. Geological Survey data release doi:10.5066/P1ZIOFSX https://doi.org/10.5066/P1ZIOFSX Smith, C.G., Cable, J.E., and Martin, J.B. 20080331 Limnology and Oceanography Volume 53, Issue 2 https://doi.org/10.4319/lo.2008.53.2.0666 Wagner, R.J., Boulger, R.W., Jr., Oblinger, C.J., and Smith, B.A. 2006 U.S. Geological Survey Techniques and Methods doi:10.3133/tm1D3 https://doi.org/10.3133/tm1D3 All data were checked for outliers and erroneous values. Outliers were corrected if possible, and any uncorrected values were not included data and flagged with the value -999. Any time stamps that have failed were removed from the dataset. Any blank data is marked with -999. Data were checked to ensure all values fall within the range of analysis for each sensor. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Accuracy was checked against global positioning system (GPS) values provided by the manufacturer. Garmin GPSMAP64st and Garmin GPSmap 60CSx FPSMAP60 accuracy, < 10 meters Accuracy was checked against global positioning system (GPS) values provided by the manufacture. Garmin GPSMAP64st and Garmin GPSmap 60CSx FPSMAP60 accuracy, < 10 meters Solinst Levelogger Description: The Solinst Levelogger measured water level (pressure above the sensor), temperature (at the sensor), and conductivity (at the sensor). The levelogger uses a Piezoresistive Silicon with Hastelloy Sensor for measurement of level; Platinum Resistance Temperature Detector (RTD) for measurement of water temperature; and 4-Electrode Platinum sensor for measurement of conductivity. The resolution for each parameter was 0.001% full scale [FS] to 0.0006% FS, 0.003 C, and 0.1 mS/cm), respectively. The logger was calibrated using a 12880 μS/cm conductivity solution prior to deployment. The logger was checked prior to each deployment using a 50000 μS/cm conductivity solution. 20221115 Christopher G. Smith U.S. Geological Survey Research Geologist mailing and physical

600 4th Street South

St. Petersburg Florida 33701 USA 727-502-8035 cgsmith@usgs.gov Data Storage and Preprocessing: Solinst LTC Dataloggers were retrieved and deployed in correspondence with the Field Activity Number 2022-340-FA with alternative FANs 22WFS05, 23WFS01, 23WFS02, 23WFS03, 23WFS04, and 24WFS01 (Chestang and others, 2025). All loggers used in study were assessed for proper in air values (i.e., atmospheric pressure in cm of water, air temperature, and conductivity of air ~0 millisemens per centimeter) prior to first deployment in November 2022. Dataloggers or loggers, henceforth, were deployed and retrieved from submerged, marine wells by divers equipped with Self-Contained Underwater Breathing Aparatus (SCUBA). Previously deployed loggers were retrieved prior to sampling and newly deployed loggers were installed following sampling as described by Chestang and others (2025). Deployed loggers were programed using Solinst Levelogger Software 5 prior to each trip; retrieved loggers were returned to land and downloaded onto a field laptop using Solinst Levelogger Software 5 as .xle files and exported as a comma separated value (CSV) file. All original data are provided in the csv files provided in this data release. 20240307 Christopher G. Smith U.S. Geological Survey Research Geologist mailing and physical

600 4th Street South

St. Petersburg Florida 33701 USA 727-502-8035 cgsmith@usgs.gov Advanced Data Processing: CSV files were imported into Microsoft Excel and data inspected for quality assurance and control reasons. Offsets (nearly instantaneous change exceeding factory parameter resolution), were compared to other sensor data and ancillary field observations (Chestang and others, 2025) and, when appropriate, were corrected using an constant offset (+/-) (Wagner and others, 2006; Smith and others, 2008). Oscillations were corrected using a ten point running mean for the duration of the observed instability (Wagner and others, 2006). Only Conductivity and temperature were processed using offset and smoothing; original data are included in the data release files for comparison. Water level or pressure remain unprocessed; unrealistic pressure data, identified as negative water levels, were replaced with no data values (-999). All original data values are provided. 20250801 Christopher G. Smith U.S. Geological Survey Research Geologist mailing and physical

600 4th Street South

St. Petersburg Florida 33701 USA 727-502-8035 cgsmith@usgs.gov WFS_SGD_LTC.zip: Fifteen CSV files of time series data collected from Indian Rocks Beach, Hudson, and Venice (Florida), beginning in November 2022 and continuing through February-March 2024. The file names consist of the area abbreviation (IRB, NC, or VH) followed by an abbreviation for month and year that data collection began (N22=November 2022, F23=February 2023, M23=May 2023, S23=September 2023, and D23=December 2023). Spreadsheet contains: date, time, level, temperature, conductivity, and original data. Detailed attribute descriptions for these files are included data dictionary (LTC_Data_Dictionary.docx). These metadata are not complete without this file. All files are available for download in WFS_SGD_LTC.zip. The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information. 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 IRBN22.csv, IRBF23.csv, IRBM23.csv, IRBS23.csv, IRBD23.csv, NCN22.csv, NCF23.csv, NCM23.csv, NCS23.csv, NCD23.csv, VHN22.csv, VHF23.csv, VHM23.csv, VHS23.csv, VHD23.csv, LTC_Data_Dictionary.docx 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, Microsoft Word format https://coastal.er.usgs.gov/data-release/doi-P13X6MBL/data/WFS_SGD_LTC.zip None 20260422 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