Nearshore bathymetry of the Koyuk River mouth, Alaska, 2024

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Buzard, Richard M., Engelstad, Anita C., and Nereson, Alexander L., 20250708, Nearshore bathymetry of the Koyuk River mouth, Alaska, 2024: data release DOI: 10.5066/P13BXTXV, Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P13YIWKC

   This is part of the following larger work.
   Erikson, Li, Gibbs, Ann E., Buzard, Richard M., Nowacki, Daniel J., Snyder, Alexander G., Engelstad, Anita C., Johnson, Cordell, Nereson, Alexander L., Over, Jin-Si R., Russel, Paul, and Lyons, Colin, 2025, In situ field data, Coastal Alaska, 2023 to 2025: data release DOI:10.5066/P13YIWKC, Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P13YIWKC

   Other_Citation_Details:

   Suggested Citation: Erikson L.H., Gibbs A.E., Buzard R.M., Nowacki D.J., Snyder A.G., Engelstad A.C., Johnson C., Nereson A.L., Over J.R., Russel, P., Lyons, C., 2025, In situ field data, Coastal Alaska, 2023 to 2025: U.S. Geological Survey data release, https://doi.org/10.5066/P13YIWKC

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -161.29880
   East_Bounding_Coordinate: -161.02413
   North_Bounding_Coordinate: 64.93214
   South_Bounding_Coordinate: 64.83365
   

3. What does it look like?

   koyuk_bathy_2024_browse.png (PNG)

   Satellite image overlain with bathymetry data points collected at the mouth of the Koyuk River, Alaska in June 2024.

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 09-Jun-2024

   Currentness_Reference:

   ground condition at the time source data were collected

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: comma-delimited text
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (856)
   2. What coordinate system is used to represent geographic features?
      

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:

      UTM_Zone_Number: 4
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -159.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is NAD83_National_Spatial_Reference_System_2011.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Datum_Name: North American Vertical Datum of 1988 GEOID12B
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

7. How does the data set describe geographic features?

   bathymetry_koyuk_river_mouth_20240609.csv

   Comma-separated value file (Source: Producer Defined)

   Easting_m_UTM

   X coordinate (easting) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) (Source: Producer Defined)

   Range of values
   Minimum:	391324.37
   Maximum:	403981.93
   Units:	meters
   Resolution:	0.01

   Northing_m_UTM

   Y coordinate (northing) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) (Source: Producer Defined)

   Range of values
   Minimum:	7191882.10
   Maximum:	7202433.56
   Units:	meters
   Resolution:	0.01

   Elevation_m_NAVD88

   Orthometric height (elevation) in meters NAVD88 GEOID12B (Source: Producer Defined)

   Range of values
   Minimum:	-6.60
   Maximum:	1.34
   Units:	meters
   Resolution:	0.01

   UTM_Zone

   Universal Transverse Mercator (UTM) zone (Source: Producer Defined)

   Value	Definition
   4N	UTM zone number

   Longitude

   Longitude in decimal degrees, WGS 1984 (Source: Producer Defined)

   Range of values
   Minimum:	-161.291487
   Maximum:	-161.029690
   Units:	decimal degrees
   Resolution:	0.00001

   Latitude

   Latitude in decimal degrees, WGS 1984 (Source: Producer Defined)

   Range of values
   Minimum:	64.834438
   Maximum:	64.930760
   Units:	decimal degrees
   Resolution:	0.00001

   Entity_and_Attribute_Overview:

   These metadata describe a comma-separated value (csv) file containing bathymetry data from the Koyuk River mouth, Alaska. The first line is a header line and each subsequent line contains x and y coordinates in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) and an orthometric height (elevation) in meters NAVD88 GEOID12B.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Richard M. Buzard
   • Anita C. Engelstad
   • Alexander L. Nereson
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   PCMSC Science Data Coordinator

   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov

Why was the data set created?

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: 09-Jun-2024 (process 1 of 5)

   Global navigation satellite system (GNSS) data set up: 1) We set up a GNSS base station (Trimble R10-2) on benchmark PID BBFB41 for the duration of the bathymetry survey, collecting at 1 hz for 9:53 hours. 2) Affix a Trimble R10-2 rover on a 2.00 m rod to the steering console of a small aluminum fishing vessel and set rover to collect waypoints continuously at 1hz while the bathymetry collection vessel is underway.

   Date: 09-Jun-2024 (process 2 of 5)

   Bathymetry data collection: 1) Launch small aluminum fishing vessel at the time of approximate local mean higher high water (1.744 m NAVD88, per Alaska Tidal Datum Portal, https://dggs.alaska.gov/hazards/coastal/ak-tidal-datum-portal.html). 2) Record instantaneous depth measurements from an aluminum vessel fitted with a transom-mounted Garmin GT20-TM transducer operating at 200 khz with a 15-degree, cone-shaped beam. 3) Read depth measurements from the screen of a Garmin Striker-series fishfinder at variable time intervals (10 s to 10 min) from while traveling less than or equal to 3.5 m/s (8mph) on smooth seas (approximately 1ft wave height). 4)Handwrite values in a field notebook along with the concurrent waypoint ID from the continuously-logging R10-2 rover. 5) After bathymetry survey, use the rover measure benchmark PID BBFB41 for control.

   Date: 10-Jun-2024 (process 3 of 5)

   Global navigation satellite system (GNSS) data processing: 1) Base station GNSS rinex files were uploaded to the Online Positioning User Service (OPUS)to obtain an accurate benchmark coordinate for post-processing of the rover data. 2) Positioning data from the survey platforms were post-processed to apply differential corrections from a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983 (2011 realization). Post-processing of raw GNSS data was performed with Trimble Business Center. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey GEOID12B offsets. The final point coordinate data from the topographic surveyors are calculated and reported in the following projected and geographic coordinates: NAD83(2011) / UTM zone 4N (EPSG: 6333) and WGS 84 (EPSG: 4326).

   Date: 07-Aug-2024 (process 4 of 5)

   Combine GNSS positions with bathymetry measurements: Subtract depth measurements from orthometric heights measured on board the aluminum fishing vessel to calculate bottom elevations in meters NAVD88, GEOID12B.

   Date: 02-Jun-2025 (process 5 of 5)

   Assess uncertainties: see Positional Accuracy report in this metadata file for more information.

3. What similar or related data should the user be aware of?

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

1. How well have the observations been checked?
   No formal attribute accuracy tests were conducted.
2. How accurate are the geographic locations?
   The mean estimated horizontal accuracy of these points is 1.78 meters. Horizontal accuracy for each point measurement was estimated by summing in quadrature the following values: 1) the horizontal precision for each point (calculated at the 95 percent confidence level by the post-processing software). Max value was 0.02 m. 2) The horizontal accuracy of the NGS OPUS-derived position of the GNSS base station operating on benchmark PID BBFB41at the 95 percent confidence level (0.02 m). And 3) the horizontal offset of the transducer from the R10-2 mounted on the steering console of the aluminum fishing vessel (1.78 m). The offset of the rover from the transducer dominates the horizontal positional uncertainties.
3. How accurate are the heights or depths?
   The mean estimated vertical accuracy of these points is 0.36 meters. Vertical accuracy for each point measurement was estimated by summing in quadrature the following values: 1) the vertical precision for each point (calculated at the 95 percent confidence level by the post-processing software). 2) The vertical accuracy of the NGS OPUS-derived position of the GNSS base station operating on benchmark PID BBFB41at the 95 percent confidence level (0.354 m). 3) The measurement resolution of the fishfinder (0.1 ft / 0.03 m). And 4) The error on the vertical offset of the of the transducer from the R10-2 mounted on the steering console of the aluminum fishing vessel (0.03 m). The vertical accuracy of the NGS OPUS-derived position of the GNSS base station dominates the vertical positional uncertainties due to the large error of GEOID12B in the region. Vertical accuracy was also assessed in two other ways: 1) In the field using two lead line depth measurements in approximately six and 12 feet of water depth, respectively. Both lead line measurements were within 0.1 ft (0.03 m) of the value measured by the transducer and read from the fishfinder. 2) The z values of point pairs in close horizontal proximity were compared to one another after post-processing. Among the three point pairs that were within 5 meters of each other, the z values of each pair member were within 0.10 m of each other. Among the 23 point pairs that were within 15 meters of one another, the z values of each pair member were within 0.80 m; and 22 of them were within 0.30 m.
4. Where are the gaps in the data? What is missing?
   Dataset 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.
5. How consistent are the relationships among the observations, including topology?
   All data falls within expected ranges.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - CMGDS

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov
2. What's the catalog number I need to order this data set? These data are available in a comma-separated value format (csv) accompanied by CSDGM FGDC-compliant metadata.
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?
   • Availability in digital form:

     Data format:	comma-delimited text file in format Comma-delimited text (version Microsoft Excel (version 2408 (Build 17928.20538 Click-to-Run))) text Size: 0.0441
     Network links:	https://doi.org/10.5066/P13YIWKC

   • Cost to order the data: None

5. What hardware or software do I need in order to use the data set?
   These data can be opened with any text viewer, spreadsheet editor, or geographic information systems (GIS) software.

Who wrote the metadata?

Dates:

Last modified: 08-Jul-2025

Metadata author:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Attn: PCMSC Science Data Coordinator

2885 Mission Street

Santa Cruz, CA

831-427-4747 (voice)

pcmsc_data@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)