Radon-222 and Water Column Data Related to Submarine Groundwater Discharge Along the Western Margin of Indian River Lagoon, Florida—September 2016 to July 2017 (ver. 2.0, March 2018)

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Frequently anticipated questions:

What does this data set describe?

Title:
Radon-222 and Water Column Data Related to Submarine Groundwater Discharge Along the Western Margin of Indian River Lagoon, Florida—September 2016 to July 2017 (ver. 2.0, March 2018)
Abstract:
Indian River Lagoon (IRL) is one of the most biologically diverse estuarine systems in the continental United States, stretching 200 kilometers (km) along the Atlantic coast of central Florida. The width of the lagoon varies between 0.5-9.0 km and is characterized by shallow, brackish waters with significant human development along both shores. Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center, working in collaboration with the St. Johns River Water Management District, mapped surface water radon-222 (radon in water) and basic physical water column properties (for example, salinity and temperature) to investigate submarine groundwater discharge at two locations, Eau Gallie North and Riverwalk Park, along the western shore of IRL. Eau Gallie North is near the central section of IRL. Riverwalk Park is approximately 20 km north of Eau Gallie site. At each study site, the radon mapping surveys were performed over seven north–south shore parallel transects (EA–EG and RA–RG, respectively), situated between 75–1000 meters offshore, and approximately 1.5 km in length. Each transect was mapped three times in an alternating north–south direction. Surface water was continuously pumped on-board into an air-water exchanger; dissolved radon-222 was purged from the water into a gaseous phase inside the exchanger. Radon-222 in the exchanger was continuously pumped into and measured by commercially available radon-in-air detectors (RAD7, Durridge, Inc.). In situ surface water temperature and salinity, as well as the water temperature in the exchanger, were also measured. Radon in air measurements were corrected to radon in water activities using the temperature-salinity dependent air-water partitioning coefficient (Schubert and others, 2012). Starting in September 2016, surveys were conducted bimonthly along the same transects to determine seasonal and temporal variability of radon-222. This data release contains the raw radon-222 data, physical water column data, Esri GIS data files and data distribution maps of the radon-222 activity and surface water salinity collected from September 2016 through July 2017.
Supplemental_Information:
The study used two mapping units, USGS 1 and USGS 2. USGS 1 consisted of three RAD7 units (2265, 2528, 2531), one RAD AQUA, and a HOBO temperature probe (7730). USGS 2 consisted of three RAD7 units (1186, 1533, 1534), one RAD AQUA, and a HOBO temperature probe (7728). Any changes to the mapping system setup, which occurred during data collection, are noted in 'IRL_Survey_Equipment.pdf.'
  1. How might this data set be cited?
    Everhart, Cheyenne S., McBride, Elsie C., Zaremba, Nicholas J., Nelson, Paul R., McCloskey, Terrence A., Smith, Christopher G., and Flint, Madison K., 20180312, Radon-222 and Water Column Data Related to Submarine Groundwater Discharge Along the Western Margin of Indian River Lagoon, Florida—September 2016 to July 2017 (ver. 2.0, March 2018): U.S. Geological Survey Data Release doi:10.5066/F7QF8S05, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -80.6881431
    East_Bounding_Coordinate: -80.588889
    North_Bounding_Coordinate: 28.28039242
    South_Bounding_Coordinate: 28.10511298
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 07-Sep-2016
    Ending_Date: 01-Aug-2017
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0197951458. Longitudes are given to the nearest 0.0223282738. Latitude and longitude values are specified in Decimal Degrees. 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.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: D WGS 1984
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: Meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    IRL_Sept_2016.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, September 2016 (USGS FAN 2016-349-FA) are also provided. (Source: USGS)
    IRL_Nov_2016.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, November 2016 (USGS FAN 2016-362-FA) are also provided. (Source: USGS)
    IRL_Jan_2017.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, January 2017 (USGS FAN 2017-306-FA) are also provided. (Source: USGS)
    IRL_March_2017.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, March 2017 (USGS FAN 2017-313-FA) are also provided. (Source: USGS)
    IRL_May_2017.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, CT2X conductivity and temperature data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, May 2017 (USGS FAN 2017-328-FA) are also provided. (Source: USGS)
    IRL_July_2017.zip
    Comma-separated values files containing the YSI data, HOBO temperature probe data, Garmin GPS data, raw RAD7 data, and compiled data including the Rn-222 activities. Shapefiles consisting of geographic, water column, and radon-222 data collected from Indian River Lagoon, FL, July 2017 (USGS FAN 2017-334-FA) are also provided. (Source: USGS)
    Rn_EGN_21.shp Rn_RWP_21.shp Rn_EGN_3_5.shp Rn_RWP_3_5.shp
    Surface water radon-222 measurements collected between September 2016 and July 2017 to investigate submarine groundwater discharge in Indian River Lagoon, FL. (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.
    Latitude
    Latitude component of GPS coordinates in decimal degrees. (Source: Garmin)
    Range of values
    Minimum:28.10544483
    Maximum:28.28039997
    Longitude
    Longitude component of GPS coordinates in decimal degrees. (Source: Garmin)
    Range of values
    Minimum:-80.68812667
    Maximum:-80.6049071
    Date
    The date data were collected in MM/DD/YYYY format. (Source: USGS)
    Range of values
    Minimum:09/07/2016
    Maximum:08/01/2017
    MapMPtTime
    The midpoint mapping date and time for Rn-222 measurements offset by either 3.5 or 21 minutes and expressed as a serial number. (Source: Microsoft Excel)
    Range of values
    Minimum:42620.40590
    Maximum:42948.41028
    Depth_m
    Water depth. NR represents 'not recorded' values. (Source: Garmin)
    Range of values
    Minimum:0.122013516
    Maximum:4.41223036
    Temp_C
    Temperature recorded by HOBO within the spray chamber in degrees Celsius. (Source: Onset Computer Corporation)
    Range of values
    Minimum:16.00
    Maximum:38.77
    InSituSal
    Salinity of the water as recorded by the YSI Pro Plus. (Source: YSI)
    Range of values
    Minimum:16.6105
    Maximum:37.283019
    dpm_L_W
    Disintegrations per minute per liter in water of radon-222. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:21.500791
    dpm_L_err
    The error associated with the value of disintegrations per minute per liter in water of radon-222. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:3.432885743
    Unit
    This number indicates whether the measurement was made by mapping system USGS 1 or USGS 2 by displaying 1 or 2. (Source: USGS) Mapping system defines the number.
    YSI_EGN.shp YSI_RWP.shp
    Water column measurements of salinity, temperature, specific conductivity, dissolved oxygen, oxidation-reduction potential (ORP), pH and barometric pressure collected between September 2016 and July 2017 to investigate submarine groundwater discharge in Indian River Lagoon, FL. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    Latitude
    Latitude component of GPS coordinates in decimal degrees. (Source: USGS)
    Range of values
    Minimum:28.10511298
    Maximum:28.28039242
    Longitude
    Longitude component of GPS coordinates in decimal degrees. (Source: USGS)
    Range of values
    Minimum:-80.6881431
    Maximum:-80.60472521
    Date
    The date data were collected in MM/DD/YYYY format. (Source: YSI)
    Range of values
    Minimum:09/07/2016
    Maximum:08/01/2017
    Time
    Time data were recorded in HH:MM:SS AM/PM format. (Source: YSI)
    Range of values
    Minimum:8:08:00 AM
    Maximum:6:17:00 PM
    Salinity
    Salinity in practical salinity units. (Source: YSI)
    Range of values
    Minimum:15.01
    Maximum:37.29
    SpC_uS_cm
    Specific conductivity in microsiemens per centimeter (uS/cm). (Source: YSI)
    Range of values
    Minimum:24828
    Maximum:56285
    DO_mg_L
    Dissolved oxygen in milligrams per liter (mg/L). NR represents 'not recorded' values. (Source: YSI)
    Range of values
    Minimum:2.17
    Maximum:11.5
    ORP_mV
    Oxidation-reduction potential in millivolts (mV). ND represents 'no data reported' values. (Source: YSI)
    Range of values
    Minimum:-162.4
    Maximum:362.4
    pH
    pH value. (Source: YSI)
    Range of values
    Minimum:7.55
    Maximum:8.62
    Temp_C
    Temperature in degrees Celsius. (Source: YSI)
    Range of values
    Minimum:15.7
    Maximum:33.6
    Baro_kPa
    Barometric pressure in kilopascals (kPa). (Source: YSI)
    Range of values
    Minimum:100.96
    Maximum:102.47
    Entity_and_Attribute_Overview:
    The detailed attribute descriptions for the raw RAD7, GPS, HOBO temperature probe, CT2X, YSI, LTC, and Rn-222 files are provided in the included data dictionaries (DataDictionary-RAD7.pdf, DataDictionary-GPS.pdf, DataDictionary-HOBO.pdf, DataDictionary-CT2X.pdf, DataDictionary-YSI.pdf, DataDictionary-LTC.pdf, and DataDictionary-Rn222.pdf, respectively). The metadata are not complete without these .pdf files.
    Entity_and_Attribute_Detail_Citation:
    The entity and attribute information was 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.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Cheyenne S. Everhart
    • Elsie C. McBride
    • Nicholas J. Zaremba
    • Paul R. Nelson
    • Terrence A. McCloskey
    • Christopher G. Smith
    • Madison K. Flint
  2. Who also contributed to the data set?
    Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Christopher G. Smith
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    cgsmith@usgs.gov

Why was the data set created?

Dissemination of radon-222, physical water column parameters, and global positioning system (GPS) data collected from Indian River Lagoon, FL from September 2016 to July 2017 (USGS Field Activity Numbers [FAN] 2016-349-FA, 2016-362-FA, 2017-306-FA, 2017-313-FA, 2017-328-FA, 2017-334-FA).

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2017 (process 1 of 7)
    From September 2016 through July 2017, a USGS barge traveled at no more than 1-1.5 knots to map radon and salinity parameters along seven shore-parallel latitudinal transects located approximately 75, 125, 200, 350, 500, 750 and 1000 m off the western edge of Indian River Lagoon, FL. A Garmin echoMAP 50s boat-mounted chartplotter GPS with a dual beam 77/200 kilohertz transducer recorded trackline information including time, position, and water depth at the Eau Gallie North (tracklines EA-EG) and Riverwalk Park (tracklines RA-RG) study sites. Each survey trackline was passed over three times; the first pass allowing the radon mapping system to equilibrate to the concentration of radon-222 in the water while the second and third passes were used to collect data once the system was equilibrated. The closest transect to shore at Eau Galle North, EA, was not run during the January-May 2017 surveys due to low water conditions. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cgsmith@usgs.gov
    Date: 2017 (process 2 of 7)
    Surface-water radon-222 (radon in water) was continuously monitored, using two multi-detector radon mapping systems, USGS 1 and USGS 2. The methodology was modelled after similar multi-detector systems used for continuous radon in water monitoring within the coastal ocean (Burnett and others, 2001; Dulaiova and others, 2005; Reich, 2009; Smith and Robbins, 2012). Each mapping system consisted of three commercial radon-in-air detectors, RAD7s, made by Durridge Company, Inc., forming a closed air tubing system where an air stream was supplied by a RAD Aqua air-water exchanger, also manufactured by Durridge. A mount secured to the side of the vessel held two AC sump-pumps that delivered a constant stream of water to two air-water exchangers, one for each mapping system. The RAD AQUAs passed the incoming water stream through spray nozzles into the spray chamber where the RAD7s’ internal pumps distribute the gas through the closed loop and pass it through a Drierite (manufactured by W.A. Hammond Drierite Co. Ltd.) desiccant column, before reaching each multi-detector mapping system. In “Normal” mode, the RAD7 analyzes radon-222 (Rn-222) activity by measuring Radon’s alpha emitting daughters of Rn-222, Polonium-214 and Polonium-218; however, during surveys only “Sniff” mode was utilized, which determines new Rn-222 by the shorter-lived Po-218 and provides a more rapid response. Each RAD7 unit was run on a 7-minute measurement cycle with the start time of USGS 2 offset 3.5 minutes from USGS 1 in order to increase spatial resolution of Rn-222 measurements. The solubility of Rn-222 in water is dependent on water temperature and salinity (Schubert and others, 2012). Water temperature within the RAD AQUA chamber was recorded by a HOBO H8 temperature probe. Attached to the vessel’s side mount was a YSI Pro Plus multiparameter meter positioned approximately 30 cm below the water surface to continuously record salinity, temperature, specific conductivity, dissolved oxygen, oxidation-reduction potential (ORP), pH and barometric pressure. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cgsmith@usgs.gov
    Date: 2017 (process 3 of 7)
    Temperature, water quality and geographic data were downloaded daily in the field as follows: (1) utilizing BoxCar Pro 4.3 (registered trademark, Onset Computer Corporation) for the HOBO H8 temperature logger, (2) YSI Data Manager software was used with the YSI Pro Plus multiparameter meter, and (3) the Garmin GPS files were saved to a micro-USB via Homeport (registered trademark, Garmin) software. To help facilitate data consolidation, analyses and archival (in a non-proprietary format) the downloaded data were exported from each sensor's internal memory and saved as comma-separated values (.csv) files. CAPTURE software (registered trademark, Durridge, Inc.) was used to download the raw RAD7 files (.r7raw) in the field after each day of mapping. The date, time, total counts, live time and Win-A % Po-218 fields were utilized to calculate stop time, average live time, total counts in window-A and the total counts per minute (cpm) in window-A for the mapping systems. The stop time is used to calculate the midpoint time within the 7-minute cycle. This midpoint mapping time is offset by 21-minutes to account for the system’s response time. An explanation of the response time can be found in the attribute accuracy report section of this metadata. Another midpoint mapping time offset of 3.5 minutes provides the most accurate radon data with respect to the time of collection but does not account for lag due to system response time. These two sets of midpoint mapping times, 3.5-minutes and 21-minutes, for each mapping system are then used to match the other parameters needed to calculate the concentration of radon-222 in water based on their timestamp. The piecewise cubic hermite interpolating polynomial (PCHIP) method in the GNU Octave software program was applied to interpolate GPS coordinates, water depth, water temperature and salinity to the midpoint mapping times offset by 3.5 and 21-minutes. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cgsmith@usgs.gov
    Date: 2017 (process 4 of 7)
    Radon in air was calculated by dividing the total cpm in window-A for each mapping system by the sum of RAD7 efficiencies for that mapping system. The air-water partitioning coefficient (Kw/air) needed to convert radon in air to radon in water was computed using the water temperature, salinity and the six parameters, a1 to b3, in the Weiss equation as determined by the experiments of Schubert and others (2012). The six unitless parameter values used were a1=-76.14, a2=120.36, a3=31.26, b1=-0.2631, b2=0.1673, and b3=-0.027. The error of the radon in water calculations was calculated by taking the square root of the total counts in window-A divided by the average live time and then multiplied by the calculated air-water partitioning coefficient. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cgsmith@usgs.gov
    Date: 2017 (process 5 of 7)
    The resulting radon in water data along with depth measurements were compiled and integrated into Esri ArcGIS shapefiles, which facilitated the creation of salinity and radon-222 activity maps. The 21-minute offset radon-222 data, which best reflects the response time of the three RAD7s and RAD Aqua mapping system, was used to create the activity maps. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cgsmith@usgs.gov
    Date: 04-Apr-2018 (process 6 of 7)
    This data release was originally posted online on January 25, 2018. Version 2.0 was released on March 12, 2018 and included the following changes (see https://coastal.er.usgs.gov/data-release/doi-F7QF8S05/data/version_history.txt for additional information): 1. Added RAD7s and RAD Aqua details. 2. Removed the oxidation-reduction potential (ORP) data for the July survey (7/30/2017 to 8/1/2017). 3. Updated the csv files, data dictionaries, and metadata text so the structure and organization conformed to a similar data release available at, https://doi.org/10.5066/F76Q1WG4. 4. Corrected the November 2016 Radon-222 values. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    aforde@usgs.gov
    Date: 13-Oct-2020 (process 7 of 7)
    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?
    Inc., DURRDIGE Company, 2017, RAD7 Radon Detector User Manual.

    Online Links:

    Inc., DURRIDGE Company, 2015, RAD AQUA Continuous Radon-in-Water Accessory for the RAD7 User Manual.

    Online Links:

    Dulaiova, H., Peterson, R., Burnett, W.C., and Lane-Smith, D., 2005, A Multi-detector Continuous Monitor for Assessment of Rn-222 in the Coastal Ocean: Journal of Radioanalytical and Nuclear Chemistry Volume 263, No. 2.

    Online Links:

    Other_Citation_Details: Pages 361-365
    Burnett, W.C., Kim, G., and Lane-Smith, D., 2001, A Continuous Monitor for Assessment of Rn-222 in the Coastal Ocean: Journal of Radioanalytical and Nuclear Chemistry Volume 249, No. 1.

    Online Links:

    Other_Citation_Details: Pages 167-172
    Schubert, M., Paschke, A., Lieberman, E., and Burnett, W.C., 2012, Air-Water Partitioning of Rn-222 and its Dependence on Water Temperature and Salinity: Environmental Science and Technology Volume 46, Issue 7.

    Online Links:

    Other_Citation_Details: Pages 3905-3911
    Reich, C.D., 2010, Investigation of Submarine Groundwater Discharge Along the Tidal Reach of the Caloosahatchee River, Southwest Florida: U.S. Geological Survey Open-File Report 2009-1273.

    Online Links:

    Other_Citation_Details: Pages 1-20
    Smith, C.G. and Robbins, L.L., 2012, Surface-water Radon-222 Distribution along the West-Central Florida Shelf: U.S. Geological Survey Open-File Report 2012-1212.

    Online Links:

    Other_Citation_Details: Pages 1-26
    Stieglitz, T.C., Cook, P.G., and Burnett, W.C., 2010, Inferring Coastal Processes from Regional-scale Mapping of 222Radon and Salinity: Examples from the Great Barrier Reef, Australia: Jounral of Environmental Radioactivity Volume 101.

    Online Links:

    Other_Citation_Details: 544-552
    Hosono, T., Ono, M., Burnett, W.C., Tokunaga, T., Taniguchi, M., and Akimichi, T., 2012, Spatial Distribution of Submarine Groundwater Discharge and Associated Nutrients within a Local Coastal Area: Environmental Science and Technology Volume 46.

    Online Links:

    Other_Citation_Details: 5319-5326

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

  1. How well have the observations been checked?
    The positional accuracy of the track lines was determined by the boat-mounted Garmin echoMAP 50s GPS receiver. The positional accuracy for the Garmin GPS ranges from better than 3 m to 10 m as outlined by the manufacture when using WAAS (Wide Area Augmentation System) coverage. Mapping system USGS 1 generally consisted of RAD7 units 2265, 2528, and 2531, with units 2976 and 4217 substituted for unit 2531 during the March 2017 and May 2017 surveys respectively. Mapping system USGS 2 consisted of RAD7 units 1186, 1533, and 1534 for all surveys. All RAD7 detector units received the recommended annual calibration by Durridge. Durridge achieves a reproducibility of better than 2% with their standard RAD7 calibration and with the overall calibration accuracy in the range of 5%. A relative humidity of 10% or below was kept to maintain the high sensitivity of the instrument during radon mapping; this was sustained by placing a drying column of Drierite desiccant in the air path of the mapping system. Per the manufacturer’s description of factors influencing the response time of the RAD7 with RAD Aqua system to changes in radon-222 concentration in water, a radon-222 data set using a 21-minute offset is provided. The 21-minute offset for this system is based on influencing factors described in the manufacture’s manual, radioactive theory, and USGS laboratory experiments (data available upon request). The laboratory experiments involved manipulation of the system air volume and flow rate of water into the RAD Aqua to assess the impact to response time. Similar radon-222 mapping studies acknowledge a 10 to 20-minute delay in response time of the three RAD7s and one RAD Aqua system but have chosen to use a 10 minute time shift for their radon-222 data due to the high water flow rates in their system setups (Hosono and others, 2012; Stieglitz and others, 2010). While these studies’ response times were closer to 10-minutes, USGS laboratory experiments suggested that 21 minutes better characterized the response time for the mapping system used in this IRL study. Radon-222 data with a 3.5-minute offset (midpoint of the 7-minute count cycle) are provided as well. The 3.5-minute offset data have not been adjusted for a system lag but provide the most accurate data with respect to time of collection. The 7-minute measurement cycle was chosen to balance the need for higher spatial resolution along the survey transects with the 21-minute response time of the system. During the March 2017 and May 2017 surveys, RAD7 unit 2531 malfunctioned and for several days the mapping system USGS1 operated with only two RAD7 units, 2265 and 2528. During the March 2017 survey (3/27/17 to 4/2/2017), a replacement RAD7 unit, 2976, was used from 4/1/2017 to 4/2/2017. In the May 2017 survey (5/22/17 to 6/3/17), replacement RAD7 unit 4217 was used from 5/31/2017 to 6/2/2017. An outline of the RAD7 units and HOBO unit used in each mapping system for all survey dates is provided in the ‘IRL_Surveys_Equipment.pdf’ document. The YSI Pro Plus multiparameter water quality meter (YSI, Inc.) was calibrated for barometer, dissolved oxygen, specific conductivity, pH, and oxidation-reduction potential (ORP) on the first field day. The YSI was checked each subsequent day with pH 7 buffer solution and 50 mS/cm conductivity solution to determine if recalibration was necessary. Linear regression of the YSI recorded salinity for both mapping systems (USGS1 and USGS 2) was used to QA/QC the data. In each YSI file, a column includes a flag indicating which data passed the QA/QC process. If the YSI probe was out of the water, the salinity values used for Rn-222 activity calculations were estimated by averaging salinity readings from YSI data collected before and after the problem time period. During September 2016, no dissolved oxygen (DO) data is available due to a malfunctioning DO probe. DO values for September 2016 are reported as ND for no data reported. During the July 2017 survey, the ORP (oxygen reduction potential) values for 7/30/2017 to 8/1/2017 were erroneous due to an incorrect calibration of the ORP standard. The ORP values for this survey are reported as ND for no data reported. HOBO H8 temperature probes were inter-compared twice a year to check the device. Linear regression of the HOBO recorded temperature for both mapping systems (USGS1 and USGS 2) was used to QA/QC data. Significant outliers that broke with the pattern of the regression and had unrealistic values based on the rest of the survey were examined as potentially erroneous. If removing these significant outliers resulted in a large improvement of the r-squared value, the outliers were considered erroneous. In each HOBO file, a column includes a flag indicating which data passed the QA/QC process. If any inconsistencies or unexpected values in ‘c:*2’ temperature data were identified, they were addressed through some of the following methods. If one HOBO reported erroneous or negative ‘c:*2’ temperature values due to a compromised connection between the HOBO and the probe, the measurements from the HOBO that recorded consistent and reliable were data were used in place of the faulty HOBO. In a situation where errors or negative ‘c:*2’ temperature values occurred with both HOBOs data recording, the relationship between verified YSI and HOBO data were assessed to produce a linear regression which allowed estimation of the temperature values for the missing measurements. A table can be found in ‘IRL_Corrections.pdf’ identifying the erroneous and negative ‘c:*2; data and how the inaccuracies were resolved for each case. When no YSI data were available, a CT2X Submersible Smart Sensor (manufactured by INW) was used to obtain salinity data. The ‘IRL_Corrections.pdf’ table also outlines the salinity errors and how they were resolved. During the July survey HOBO 7728 was replaced with HOBO 4828 on 7/29/2017 in order to have a functioning HOBO for USGS 2. HOBO 7728 reported only negative values on 7/26/2017 and 7/27/2017 and therefore that data was not reported. Reported radon-222 data excludes the data at the beginning of each day where appropriate temperature data was unavailable because the HOBOs were not yet exposed to surface water at that time. Due to the depth limitations of the Garmin echosounder, the shallowest transects of the Eau Gallie North site are lacking recorded depths have been reported as ‘NR’ for not recorded. The transducer offsets are provided in the GPS csv files for each survey trip. When the transducer water depth was not measured in the field, the water depth measurements of a similarly positioned Solinist Levelogger (which includes level, temperature, conductivity (LTC) data) were used to adjust the Garmin GPS water depth values for the transducer offset. The water depths were averaged for each day and that offset subtracted from Garmin GPS water depths.
  2. How accurate are the geographic locations?
    The horizontal accuracy of the sample locations was determined by the accuracy of the boat-mounted Garmin echoMAP 50s chartplotter 10 Hertz GPS receiver, which recorded the positional data of the boat during data collection. The positional accuracy for the Garmin GPS ranges from better than 3 m to 10 m as outlined by the manufacture when using WAAS (Wide Area Augmentation System) coverage.
  3. How accurate are the heights or depths?
    The vertical positional accuracy of the water depth measurements was determined by the boat-mounted Garmin echoMAP 50s transducer. The transducer used with the Garmin echoMAP 50s chartplotter is a dual beam transducer that transmits a 77/200 kHz signal. The transducer cannot measure depths shallower than ~0.7 m.
  4. Where are the gaps in the data? What is missing?
    This is a complete, processed data set for all radon-222, physical water column parameters, and global positioning system (GPS) data collected from Indian River Lagoon from September 2016 to July 2017 (USGS Field Activity Numbers [FAN] 2016-349-FA, 2016-362-FA, 2017-306-FA, 2017-313-FA, 2017-328-FA, 2017-334-FA).
  5. How consistent are the relationships among the observations, including topology?
    This dataset contains the raw RAD7, HOBO, YSI, CT2X, and GPS data files produced by the RAD7s (Durridge, Inc.), the HOBO temperature probes, the YSI Pro Plus multimeter, CT2X conductivity and temperature sensor (May 2017 survey only), LTC data (November 2016 and January 2017 surveys) and the boat-mounted Garmin GPS receiver. All supplementary field notes are available upon request.

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 U.S. Geological Survey requests to be acknowledged as originator of the data in future products or derivative research. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: Christopher G. Smith
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    cgsmith@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, 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 imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    The data tables are provided as comma-separated values text files (.csv). The .csv data file contains the tabular data in plain text and may be viewed with a standard text editor. Portable Document Format (PDF) files can be viewed using the free software Adobe Acrobat Reader (http://get.adobe.com/reader). The GIS Esri shapefiles (.shp) can be opened using the free ArcGIS Explorer (https://www.esri.com/software/arcgis/explorer). The data figures are provided as Joint Photographic Experts Group (JPEG) images and can be viewed using standard image viewing software.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
U.S. Geological Survey
Attn: Christopher G. Smith
600 4th Street South
St. Petersburg, FL

727-502-8000 (voice)
cgsmith@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/IRL_metadata_v2.faq.html>
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