Discharge Measurements in Bayou Heron and Bayou Middle, Grand Bay, Mississippi, January 2017

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Frequently anticipated questions:

What does this data set describe?

Title:
Discharge Measurements in Bayou Heron and Bayou Middle, Grand Bay, Mississippi, January 2017
Abstract:
Grand Bay, a 30-square-kilometer embayment of the Gulf of Mexico bordered by 20 square kilometers of salt marsh, is experiencing rapid lateral shoreline erosion at up to 5 meters per year. Determining whether the eroded sediment is exported to the deep ocean or imported via tidal channels and deposited on the marsh platform is critical to understanding the long-term response of the marsh to wave attack and sea-level rise. Quantifying water-column sediment flux helps to characterize the role of tidal channels in this process, and water discharge is a key component of sediment flux. To that end, discharge was measured repeatedly over consecutive diurnal tidal cycles in the tidal channels of Bayou Heron and Bayou Middle, within Grand Bay National Wildlife Refuge, Mississippi on January 24–28, 2017. These data were collected by using a Teledyne RDI Rio Grande 1200-kilohertz acoustic Doppler current profiler (ADCP). Downward-looking ADCP transect data were collected from a moving boat and initially reviewed by using WinRiver II, and reprocessing and final review was completed by using QRev.
Supplemental_Information:
These data were collected as part of a six-month-long study of flow velocity, sediment transport, waves, and water quality within Grand Bay. The larger study included long-term time-series deployments of oceanographic instrumentation, with the goal of measuring water-column sediment fluxes and relating them to observed shoreline erosion. More information about the field activity during which these data were collected is available at https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-006-FA. More information about the Estuarine Processes, Hazards, and Ecosystems project, which conducted the long-term study, is available at https://woodshole.er.usgs.gov/project-pages/estuaries/.
The index-velocity relationship is based on Ruhl and Simpson, 2005 (see cross-references).
  1. How might this data set be cited?
    Nowacki, Daniel J., Ganju, Neil K., Suttles, Steven E., Borden, Jonathan, and Nichols, Alexander R., 2018, Discharge Measurements in Bayou Heron and Bayou Middle, Grand Bay, Mississippi, January 2017: data release DOI:10.5066/P98NHB82, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Nowacki, D.J., Ganju, N.K., Suttles, S.E., Borden, J., and Nichols, A.R., 2018, Discharge measurements in Bayou Heron and Bayou Middle, Grand Bay, Mississippi, January 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P98NHB82.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.410640
    East_Bounding_Coordinate: -88.397007
    North_Bounding_Coordinate: 30.388290
    South_Bounding_Coordinate: 30.386995
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5b296aa4e4b059207627a343?name=GrandBay_ADCP_browse.jpg (JPEG)
    Photograph of moving-boat ADCP discharge measurements being made in Bayou Heron
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 24-Jan-2017
    Ending_Date: 28-Jan-2017
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: binary and text
  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 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in degrees and decimal minutes. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    This dataset consists of discharge measurements collected using a Teledyne RD Instruments Rio Grande ADCP (Teledyne RD Instruments, 2013). All data were collected with Teledyne RD Instruments WinRiver II version 2.17 (Teledyne RD Instruments, 2016) and processed with QRev version 3.43 (Mueller, 2016). Due to the complexity of an ADCP data file and the various algorithms applied to compute the streamflow from ADCP data, these data are most useful in either 1) their original raw data format which can be opened and processed in either WinRiver II or QRev or 2) their processed format which can be opened and processed by QRev or opened by Matlab or any software that can read Matlab formatted files. Both WinRiver II and QRev are distributed free.
    The data are divided into folders based on location and acquisition time, and further divided by software association.
    The top-level folders are Bayou_Heron_1, Bayou_Heron_2, Bayou_Middle_1, and Bayou_Middle_2.
    Each of these folders contains two subfolders: QRev_Files and WinRiver_II_Files.
    The WinRiver II files consist of:
    1. .mmt file: XML configuration file used by WinRiver II for setup, specific measurement data entry, and filenames of the raw transect data files (pd0)
    2. .pd0 files: raw binary data collected by WinRiver II. The format for these files is defined in Teledyne RD Instruments (2013).
    The QRev files consist of:
    1. .mat files: saved data processed by QRev. These files can be opened and processed by QRev or loaded into Matlab or software that can read Matlab formatted files. The variable definitions are documented in Mueller (2016).
    2. .xml: summaries of the data processed by QRev. The variable definitions are documented in Mueller (2016). The primary variables used in the index-velocity computation are the total discharge, located in Channel:Transect:Discharge:Total, and the channel cross-sectional area, located in Channel:Transect:Other:Area.
    This dataset is in the form of a zip file, Grand_Bay_ADCP.zip, with the following folder structure:
    Bayou_Heron_1/QRev_Files:
    20180524_204513_BT_QRev.mat: QRev processed data in Matlab format
    20180524_204513_BT_QRev.xml: QRev XML summary file
    QRevStylesheet.xsl: XML stylesheet
    Bayou_Heron_1/WinRiver_II_Files:
    GB2_0.mmt: XML configuration file
    GB2_0_yyy_xx-xx-xx.PD0: Raw binary data where yyy is the transect number, and xx-xx-xx is the date in the format year-month-day.
    Bayou_Heron_2/QRev_Files:
    20180524_205703_BT_QRev.mat: QRev processed data in Matlab format
    20180524_205703_BT_QRev.xml: QRev XML summary file
    QRevStylesheet.xsl: XML stylesheet
    Bayou_Heron_2/WinRiver_II_Files:
    GB2_2_0.mmt: XML configuration file
    GB2_2_0_xxx_xx-xx-xx.PD0: Raw binary data where yyy is the transect number, and xx-xx-xx is the date in the format year-month-day.
    Bayou_Middle_1/QRev_Files:
    20180525_155226_BT_QRev.mat: QRev processed data in Matlab format
    20180525_155226_BT_QRev.xml: QRev XML summary file
    QRevStylesheet.xsl: XML stylesheet
    Bayou_Middle_1/WinRiver_II_Files:
    GB4_1_0.mmt: XML configuration file
    GB4_1_0_xxx_xx-xx-xx.PD0: Raw binary data where yyy is the transect number, and xx-xx-xx is the date in the format year-month-day.
    Bayou_Middle_2/QRev_Files:
    20180524_212416_BT_QRev.mat: QRev processed data in Matlab format
    20180524_212416_BT_QRev.xml: QRev XML summary file
    QRevStylesheet.xsl: XML stylesheet
    Bayou_Middle_2/WinRiver_II_Files:
    GB4_2_0.mmt: XML configuration file
    GB4_2_0_xxx_xx-xx-xx.PD0: Raw binary data where yyy is the transect number, and xx-xx-xx is the date in the format year-month-day.
    Additional details are contained in a separate README.txt file.
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2017-006-FA

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Daniel J. Nowacki
    • Neil K. Ganju
    • Steven E. Suttles
    • Jonathan Borden
    • Alexander R. Nichols
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Daniel J Nowacki
    U.S. Geological Survey
    Research Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-548-8700 x2332 (voice)
    508-457-2310 (FAX)
    dnowacki@usgs.gov

Why was the data set created?

The discharge measurements were used as part of a process to create an index-velocity relationship between flow velocity measured at a single location within the channel and the channel-average velocity. This relationship enables the computation of a time-series of total channel discharge from long-term deployments of oceanographic instrumentation measuring at a single location within the channel.

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: Jan-2017 (process 1 of 3)
    Discharge data were collected using a boat-mounted Teledyne RDI Rio Grande 1200 kHz acoustic Doppler current profiler (ADCP), serial number 12974, in two tidal channels, known as Bayou Heron and Bayou Middle. The boat repeatedly traversed each channel from one bank to the other, collecting data during each transect crossing. The dates and times of the transect measurements were chosen to cover as much of a full diurnal tidal cycle as possible, subject to logistical and safety constraints. ADCP data were recorded and initially reviewed using WinRiver II version 2.17. WinRiver II is available at http://www.teledynemarine.com/rdi/support. The raw data were recorded in .mmt and .pd0 files, which are the native file formats of WinRiver II. WinRiver II integrated position data from an Ashtech AeroAntenna AT3075-2A antenna and Thales DG16 GPS receiver. Note that although the GPS data were recorded, they were not used for the final data product.
    Bayou Heron is a tidal channel approximately 150 m in width, with a maximum depth of approximately 3 m. Data were collected on January 24–25, 2017 in two datasets. The first dataset (Bayou_Heron_1) has the date range January 24, 2017 22:08–January 25, 2017 06:34. The second dataset (Bayou_Heron_2) has the date range January 25, 2017 18:57–January 25, 2017 23:51. All dates and times are in UTC.
    Bayou Middle is a tidal channel approximately 50 m in width, with a maximum depth of approximately 3 m. Data were collected on January 26–28, 2018 in two datasets. The first dataset (Bayou_Middle_1) has the date range January 26, 2017 21:59–January 27, 2017 07:20. The second dataset (Bayou_Middle_2) has the date range January 27, 2017 19:29–January 28, 2017 00:29. All dates and times are in UTC.
    Date: 25-May-2018 (process 2 of 3)
    Data were post-processed using QRev 3.43, a program developed by the USGS Office of Surface Water to compute moving-boat ADCP discharge. QRev automates data-quality checks, data filtering, extrapolation methods, and invalid-data-handling steps, and provides estimates of uncertainty to help guide the user. QRev is available at https://hydroacoustics.usgs.gov/movingboat/QRev.shtml. Processing in QRev adhered to the defaults except as outlined below.
    For both sites, a salinity of 17 PSU was applied based on field measurements of water-column salinity using using a YSI EXO2 multiparameter sonde. Using a field-measured salinity improves the estimate of speed of sound in water, which is used in computing the discharge data.
    For Bayou Heron, a spurious transect (008), which included data from two channel crossings, was screened from the final dataset.
    For Bayou Middle, spurious transects (000, 010, 016, 030) were removed from the first dataset, and a spurious transect (021) was removed from the second dataset. These were removed because they contained data either only for a partial transect, or for more than a full transect, because of operational error or logistical constraints.
    For both sites, data were exported from QRev using bottom-track (BT) navigation reference. Although data using GPS fix (GGA) navigation reference could be exported from QRev, the BT data are considered to be more reliable given the large number of invalid GGA ensembles and poor unfiltered differential GPS data quality.
    Date: 06-Aug-2020 (process 3 of 3)
    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?
    Mueller, David S., 2016, QRev—Software for computation and quality assurance of acoustic doppler current profiler moving-boat streamflow measurements—Technical manual for version 2.8: Open-File Report 2016-1068, U.S. Geological Survey, Reston, VA.

    Online Links:

    Ruhl, Catherine A., and Simpson, Michael R., 2005, Computation of Discharge Using the Index-Velocity Method in Tidally Affected Areas: Scientific Investigations Report 2005-5004, U.S. Geological Survey, Reston, VA.

    Online Links:

    Teledyne RD Instruments, Inc., 2016, WinRiver II Software User's Guide: Teledyne RD Instruments, Inc., San Diego, CA.

    Online Links:

    Other_Citation_Details: P/N 957-6231-00
    Teledyne RD Instruments, Inc., 2013, Workhorse Rio Grande ADCP Guide: Teledyne RD Instruments, Inc., San Diego, CA.

    Online Links:

    Other_Citation_Details: P/N 957-6241-00

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

  1. How well have the observations been checked?
    Data were processed using QRev and reviewed by staff experienced in ADCP discharge measurements. The consistency of flow direction, the characteristics of a given transect compared to those completed before and after it, and the characteristics of a given transect compared to the mean of all transects were used to determine the accuracy and validity of each transect. QRev uses a color-coded scheme in its graphical user interface to indicate potential areas of concern (e.g., percent change in discharge magnitude between consecutive transects). Because these measurements were made in tidal systems, these changes are expected and many of the yellow- and red-colored regions in QRev are to be expected. ADCP data were collected in relatively large (0.5 m) depth bins compared to the total depth of the channels, particularly near the edges. As a result, little valid data were collected over shallower portions of the channels, resulting in poorly constrained discharge estimates in these regions.
  2. How accurate are the geographic locations?
    GPS locations were collected using an Ashtech AeroAntenna AT3075-2A antenna and Thales DG16 GPS receiver. The GPS antenna was located directly above the ADCP during data collection. Based on manufacturer specifications, the locations are assumed to be accurate within 2 m Circular Error Probable (CEP).
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented. Certain transects were removed during processing as described in the Lineage.
  5. How consistent are the relationships among the observations, including topology?
    Data were processed using QRev and reviewed by staff experienced in ADCP discharge measurements. All data were collected using the same instrument, computer, and moving-boat platform, and were processed using the same software configuration. See Lineage for more information.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Info' for details.
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) 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
    United States

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This dataset is in the form of a zip file, Grand_Bay_ADCP.zip, which contains folders and files as described in the Entity and Attribute Overview.
  3. What legal disclaimers am I supposed to read?
    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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 06-Aug-2020
Metadata author:
Daniel J Nowacki
U.S. Geological Survey
Research Oceanographer
384 Woods Hole Road
Woods Hole, MA
US

508-548-8700 x2332 (voice)
508-457-2310 (FAX)
dnowacki@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_P98NHB82/GrandBay_ADCP_Metadata.faq.html>
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