{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Mark Nardi", "hasEmail": "mailto:mrnardi@usgs.gov"}, "description": "This spatial data layer is a cell-based Raster model characterizing the contribution of phosphorus (P) \nto streams from weathering and erosion of surficial geologic materials for the conterminous United \nStates, and has been created as part of the SPARROW (Spatially Referenced Regressions on \nWatershed Attributes) water-quality model implementation. SPARROW provides estimates of total \nnitrogen and phosphorus load in surface waters from point and non-point sources. This data set \nrepresents only potential for P contributions, and does not include N. The characterization of \ncontribution of P from geologic materials will help separate the effects of natural or background \nsources from anthropogenic sources of P, such as from municipal wastewater or agricultural \npractices. The potential of a watershed to contribute P from naturally occurring geologic materials \nin the watershed to the adjacent receiving stream is characterized using geochemical data from \nbed-sediment samples (USGS National Geochemical Survey, National Uranium Resource \nEvaluation (NURE), Smith 1979) collected from first-order streams in relatively undisturbed watersheds.  \nBed sediment samples were collected from 1975 through 1980. The bed-sediment phosphorus \nconcentrations (BSPconc) in this data set represent BSPconc in the absence of anthropogenic \nsources and therefore spatial variation in BSPconc can be used to indicate spatial variation in the \npotential to contribute naturally occurring P from the geologic materials in the watershed to the \nstream. A continuous mapped distribution of BSPconc in headwater streams for the conterminous \nU.S. was prepared by summarizing BSPconc from 50,740 bed-sediment samples by geologic unit \nusing regional-scale geologic map units (GMU's). The GMU's delineate areas with similar \nlithochemistry based on geologic age as well as ecoregion units. GMU\u2019s were created by \ncombining surficial geology (Hunt, Charles D., 1979) with Level IV Ecoregion units (U.S. Environmental \nProtection Agency 2011). This data set represents the mean BSPconc value for each GMU. The \nspatial pattern of BSPconc in headwater streams is offered as a data layer, representing best \navailable information at the regional scale, with the caveat that its performance as a surrogate for \ncontribution of P from watershed geologic materials to in-stream levels of P is weakened by not \naccounting for variability across headwater streams in the rates of net deposition and processing \nof P in the streambed.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9PQNFXO", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.1abd47df-7a09-4003-987e-97e5196b7712.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_1abd47df-7a09-4003-987e-97e5196b7712", "keyword": ["SPARROW model", "USGS:1abd47df-7a09-4003-987e-97e5196b7712", "bed sediment", "eco regions", "environment", "geoscientificInformation", "inlandWaters", "phosphorus", "streams", "surficial geology"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-127.900289121, 22.894343093, -65.334157352, 50.591453065", "theme": ["geospatial"], "title": "Watershed Potential to Contribute Phosphorus from Geologic Materials to Receiving Streams, Conterminous United States"}