{
    "tag": 19202,
    "title": "Sediment grain size from the Elwha River, Washington, 2006 to 2022 (ver. 2.0, July 2025)",
    "pubdate": "20180604",
    "sername": null,
    "series_name": null,
    "issue": "doi:10.5066\/F76972SC",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/pcmsc\/DataReleases\/ScienceBase\/DR_F76972SC\/GrainSizes_ElwhaRiver_2006to2022_metadata.faq.html",
    "format": null,
    "email": null,
    "descript": "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 \u201cOffTransect\u201d 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\u2013165, 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\u20131821, 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\u2013956, https:\/\/doi.org\/10.1029\/TR035i006p00951.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "East, Amy E.",
            "role": "Author"
        },
        {
            "name": "Logan, Joshua B.",
            "role": "Author"
        },
        {
            "name": "Mastin, Mark C.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "375",
            "name": "field inventory and monitoring",
            "scope": "Repeated observation or sampling at a site, on a scheduled or event basis, for study and analysis.  In general, this category excludes sampling programs in which materials are obtained in the field and brought back to a laboratory for study and analysis."
        },
        {
            "thcode": 2,
            "code": "493",
            "name": "grain-size analysis",
            "scope": "Method of studying soils, sediments, sands, or rock by determining the size, distribution, and proportion of selected particles."
        },
        {
            "thcode": 2,
            "code": "500",
            "name": "gravel deposits",
            "scope": "Alluvial accumulations of small unconsolidated rock fragments, such as pebbles and cobbles, used in construction as fill, ground cover, or aggregate for concrete."
        },
        {
            "thcode": 2,
            "code": "1001",
            "name": "river reaches",
            "scope": "Continuous parts of streams between two specified points."
        },
        {
            "thcode": 2,
            "code": "1002",
            "name": "river systems",
            "scope": "Long water courses including main streams and tributaries."
        },
        {
            "thcode": 2,
            "code": "1034",
            "name": "sediment transport",
            "scope": "Transport of solid particles of unconsolidated rock and mineral fragments, chemical precipitates, or biological materials."
        },
        {
            "thcode": 15,
            "code": "012",
            "name": "inlandWaters",
            "scope": "Inland water features, drainage systems and characteristics, for example rivers and glaciers, salt lakes, water utilization plans, dams, currents, floods and flood hazards, water quality, hydrographic charts, watersheds, wetlands, hydrography"
        },
        {
            "thcode": 23,
            "code": "23",
            "name": "Substrate",
            "scope": "Represents the character and composition of the surface and near surface of the sea floor in subtidal or intertidal areas, as defined in the Substrate Component of CMECS or in similar classification systems. Distributions are records of substrate characteristics based on visual or photographic inspection or on analysis of samples and cores, and they also include interpretive maps classifying areas on the basis of combinations of observations, hydrodynamic models, or geological models. Assessments include evaluations of present ecological or economic values of substrate distributions, drivers of substrate change, and functions of substrates. Predictions are the results of models or projections of future substrate distributions, values, or ecological impacts, including predicted substrate changes due to natural and human forces including erosion, accretion, sea-level change, extraction, trawling, or other factors; and they are the results of scenario-based models of substrate changes on ecological or economic values under different management strategies or other human alterations."
        }
    ],
    "place_term": [],
    "image": [
        {
            "name": "https:\/\/www.sciencebase.gov\/catalog\/file\/get\/5a6fbc11e4b06e28e9cad6f6?name=Elwha_ReachTransectLocations.jpg&allowOpen=true",
            "description": "Image map showing locations of study reaches and transects along the Elwha River, Washington"
        }
    ],
    "fan": []
}