Sediment grain size from the Elwha River, Washington, 2006 to 2022 (ver. 2.0, July 2025)

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Frequently anticipated questions:

What does this data set describe?

Title:
Sediment grain size from the Elwha River, Washington, 2006 to 2022 (ver. 2.0, July 2025)
Abstract:
The grain size of sediment on the riverbed was measured during 21 surveys on the Elwha River, Washington, between 2006 and 2022. Most data were collected along the same transects where channel topography was measured (see related child item in this data release with river-channel topography). Measurements of sediment ranging from medium sand to boulders were made using the CobbleCam digital photographic technique (Warrick and others, 2009), which uses a calibrated autocorrelation algorithm (Rubin, 2004) to calculate the mean grain size of sediment from pixels in downward-looking digital photographs. This technique yields grain-size values accurate to within 14 percent of those obtained by pebble counting (Wolman, 1954; Warrick and others, 2009). For samples finer than medium sand, we measured grain size using a Coulter laser particle-size analyzer at the USGS laboratory in Santa Cruz, California. Grain size was measured along subaerial portions of the survey transects within the bankfull channel. We also measured grain size of some sediment deposited after dam removal that did not coincide with survey transects (these sample locations are labeled “OffTransect” in the data file). References: Rubin, D.M., 2004, A simple autocorrelation algorithm for determining grain size from digital images of sediment: Journal of Sedimentary Research 74, p. 160–165, https://doi.org/10.1306/052203740160. Warrick, J.A., Rubin, D.M., Ruggiero, P., Harney, J.N., Draut, A.E., and Buscombe, D., 2009, Cobble Cam: grain-size measurements of sand to boulder from digital photographs and autocorrelation analyses: Earth Surface Processes and Landforms 34, p. 1811–1821, https://doi.org/10.1002/esp.1877. Wolman, M.G., 1954, A method of sampling coarse river-bed material: Eos Trans. AGU 35, p. 951–956, https://doi.org/10.1029/TR035i006p00951.
Supplemental_Information:
Information about the data collection field activities can be found at: http://cmgds.marine.usgs.gov/fan_info.php?fan=2022-632-FA http://cmgds.marine.usgs.gov/fan_info.php?fan=2017-659-FA http://cmgds.marine.usgs.gov/fan_info.php?fan=2015-656-FA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER114WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER113WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER112WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER111WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER210WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER110WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER209WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER109WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER208WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER108WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER107WA http://cmgds.marine.usgs.gov/fan_info.php?fan=ER106WA http://cmgds.marine.usgs.gov/fan_info.php?fan=W106PS
  1. How might this data set be cited?
    East, Amy E, Logan, Joshua B, and Mastin, Mark C, 20180604, Sediment grain size from the Elwha River, Washington, 2006 to 2022 (ver. 2.0, July 2025): data release doi:10.5066/F76972SC, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    East, Amy E, Logan, Joshua B, and Mastin, Mark C, 2018, River-channel topography and sediment grain size on the Elwha River, Washington, 2006 to 2022 (ver. 2.0, July 2025): data release doi:10.5066/F76972SC, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.625
    East_Bounding_Coordinate: -123.54
    North_Bounding_Coordinate: 48.151755
    South_Bounding_Coordinate: 47.954370
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5a6fbc11e4b06e28e9cad6f6?name=Elwha_ReachTransectLocations.jpg&allowOpen=true (JPG)
    Image map showing locations of study reaches and transects along the Elwha River, Washington
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2006
    Ending_Date: 2022
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: comma-separated values
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: Data were collected along the Elwha River, Washington
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (5248)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.0
      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 0.001
      Ordinates (y-coordinates) are specified to the nearest 0.001
      Planar coordinates are specified in METERS
      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.26.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1983
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    GrainSizes_ElwhaRiver_2006to2022.csv
    Grain size calculations for the Elwha River, 2006 to 2022 (Source: U.S. Geological Survey)
    SEASON
    The season during the year in which the data was collected (Source: U.S. Geological Survey) "Fall," "Spring," and "Summer" refer to the northern hemisphere season during which the data was collected
    DATE
    Data of the data collection, in ISO date format (year-month-day) (Source: U.S. Geological Survey)
    Range of values
    Minimum:2006-09-23
    Maximum:2022-08-28
    Units:year-month-day
    REACH
    A unique location identifier indicating the name of the river reach where data was collected (Source: U.S. Geological Survey)
    ValueDefinition
    CRControl reach
    R1Reach 1
    R1BReach 1B
    R2Reach 2
    R3Reach 3
    TRANSECT
    Transect identifying code, formatted as "reach-transect." For example, "R2-T3" represents Reach 2 Transect 3. (Source: U.S. Geological Survey) See "REACH" attribute for “reach-” identifying codes. For the “transect” portion of the alpha-numeric code, the following definitions are used: T0=Transect 0; T1=Transect 1; T2=Transect 2; T3=Transect 3; T3B=Transect 3B; T4=Transect 4; T5=Transect 5; T6=Transect 6; SC5-T1=Side channel 5, transect 1; SC5-T2B=Side channel 5, transect 2B; SC5-T3=Side channel 5, transect 3; OffTransect=elevation points collected off transect. Note that transects associated with side channel 5 (SC5; not shown on index map) are separately numbered transects than the transects in the rest of Reach 2. Additionally, SC5-T2B is located between transects SC5 transects 2 and 3.
    MEAN-MM
    The mean particle size in the sample, measured in millimeters (mm). Measurements derived from CobbleCam are listed to 1 decimal place. Measurements derived from Sediment Lab are listed to 4 decimal places. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.0
    Maximum:643.9
    Units:millimeters
    MEAN-PHI
    The mean particle size in the sample, measured in phi units. Measurements derived from CobbleCam are listed to 4 decimal places. Measurements derived from Sediment Lab are listed to 6 decimal places. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-9.330700
    Maximum:6.898093
    Units:phi units
    ANALYSIS_METHOD
    The method in which the sample was analyzed to determine grain size (Source: U.S. Geological Survey)
    ValueDefinition
    CobbleCamCobble Cam photographic autocorrelation analysis was used to determine grain size.
    SedimentLabA physical sample was collected and analyzed in the USGS PCMSC sediment lab.
    LOCATION_METHOD
    The method in which the sample was geographically located (Source: U.S. Geological Survey)
    ValueDefinition
    SurveyedPoint was surveyed using GPS and total station methods.
    InterpolatedPoint was between two survey points and N, E, and Z values were interpolated between the two survey points
    ApproximatePoint was either on a transect but precise position was not measured (N and E values are derived from the mid-point of the transect); or point was off transect (TRANSECT=OffTransect) and N and E values derived from a point at the center of the study reach. Neither instance has a Z value. See the "TRANSECT" column to distinguish between the two cases.
    PID
    Unique identifier for the survey point collection ID. Unique for survey date at reach, but not unique between reaches, or between dates. (PID values may be repeated in the same file on separate dates). A PID value of -9999 indicates that the point was not surveyed with topographic measurements and was either interpolated or approximated. (Source: U.S. Geological Survey)
    Range of values
    Minimum:15
    Maximum:9155
    N
    Northing. Surveyed positions are listed to 3 decimal places. Interpolated positions are listed to 1 decimal place. Approximated positions are listed with integer precision. (Source: North American Datum of 1983, UTM Zone 10N)
    Range of values
    Minimum:5311439.687
    Maximum:5332527.804
    Units:meters
    E
    Easting. Surveyed positions are listed to 3 decimal places. Interpolated positions are listed to 1 decimal place. Approximated positions are listed with integer precision. (Source: North American Datum of 1983, UTM Zone 10N)
    Range of values
    Minimum:457159.339
    Maximum:459047.541
    Units:meters
    Z
    Elevation. Surveyed positions are listed to 3 decimal places. Interpolated positions are listed to 1 decimal place. "NaN" indicates no value was collected or position was approximated (Source: North American Vertical Datum of 1988)
    Range of values
    Minimum:0.806
    Maximum:219.114
    Units:meters
    DISTANCE
    Distance from start point of transect, in meters. Off-transect points with no relevant transect start point are assigned a value of "NaN". (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.000
    Maximum:151.174
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Amy E East
    • Joshua B Logan
    • Mark C Mastin
  2. Who also contributed to the data set?
    Data collection was funded by U.S. Geological Survey
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    United States

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

Data were collected to study sediment in the Elwha River before and after the removal of the Glines Canyon and Elwha dams.

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: 2022 (process 1 of 5)
    Measurements on sediment ranging from medium sand to boulders were made using the CobbleCam digital photographic technique (Warrick and others, 2009), which uses a calibrated autocorrelation algorithm (Rubin, 2004) to calculate the mean grain size of sediment from pixels in downward-looking digital photographs. This technique yields grain-size values accurate to within 14 percent of those obtained by pebble counting (Wolman, 1954). For samples finer than medium sand, we measured grain size using a Coulter laser particle-size analyzer at the USGS sediment laboratory in Santa Cruz, California, after removing any organic matter with a hydrogen peroxide solution. Grain size was measured along subaerial portions of the survey transects within the bankfull channel. We also measured grain size in parts of the study reaches containing new sediment deposits (after dam removal) that did not coincide with survey transects, collecting enough additional data in such cases to avoid spatial bias and ensure that grain-size measurements represented both the newly deposited material and any older sediment still exposed. In such cases, the data are coded as "OffTransect."
    Date: 17-Jul-2018 (process 2 of 5)
    Corrected name of theme keyword thesaurus from ISO 19115 Topic Categories to Category. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 05-Sep-2018 (process 3 of 5)
    Corrected Point of Contact and Metadata Contact phone number prefix. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 4 of 5)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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
    Date: 30-May-2025 (process 5 of 5)
    Changes to version 2.0 of data release: - Added data from 2022 August survey (2022-632-FA). - Standardized numeric precision for MEAN-MM and MEAN-PHI, depending on ANALYSIS_METHOD. - Standardized numeric precision for N, E, Z, and Distance, depending on LOCATION_METHOD. - Added NaN values for all empty data. - Re-sorted based on Reach, Date, Transect, Distance. - Changed SEASON attribute to conform to standard definitions of season in northern hemisphere. Some samples from early September were reclassified as "Summer". Person who carried out this activity:
    U.S. Geological Survey
    Attn: Joshua Logan
    Physical Scientist
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7519 (voice)
    jlogan@usgs.gov
  3. What similar or related data should the user be aware of?
    Wolman, M G, 1954, A method of sampling coarse river-bed material: Transactions, American Geophysical Union, 35(6), United States.

    Rubin, David M, 2004, A simple autocorrelation algorithm for determining grain size from digital images of sediment: Journal of Sedimentary Research, 74(1), Tulsa, OK.

    Warrick, John A, Rubin, David M, Ruggiero, Peter, Harney, Jodi N, and Draut, Amy E, 2009, Cobble Cam: grain-size measurements of sand to boulder from digital photographs and autocorrelation analyses: Earth Surface Processes and Landforms, 34, online.

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

  1. How well have the observations been checked?
    Data values are within the expected values.
  2. How accurate are the geographic locations?
    Initial survey control for all transects was established using static GPS occupations, which have an estimated horizontal accuracy of around 1.5 cm. Subsequent survey control densification within each reach was conducted using a total station. Repeat check measurements conducted during the surveys on points with established coordinates suggest a horizontal precision of around 3 cm for measurements at these sites.
  3. How accurate are the heights or depths?
    Initial survey control for all transects was established using static GPS occupations, which have an estimated vertical accuracy of around 2.5 cm. Subsequent survey control densification within each reach was conducted using a total station. Repeat check measurements conducted during the surveys on points with established coordinates suggest a vertical precision of around 3 cm for measurements at these sites.
  4. Where are the gaps in the data? What is missing?
    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.
  5. How consistent are the relationships among the observations, including topology?
    Data values are within the expected values.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints no access constraints
Use_Constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey (USGS) as the originator of the dataset and in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    U.S. Geological Survey
    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? These data are available in csv format (GrainSizes_ElwhaRiver_2006to2022.csv), along with an image map of the study area and CSDGM FGDC-compliant metadata all contained in a single zip file.
  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?
  5. What hardware or software do I need in order to use the data set?
    The data are available in comma-separated values (CSV) spreadsheet format. Text editing software can be used to open the file, as well as spreadsheet programs, such as Microsoft Excel.

Who wrote the metadata?

Dates:
Last modified: 03-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
United States

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/ScienceBase/DR_F76972SC/GrainSizes_ElwhaRiver_2006to2022_metadata.faq.html>
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