{
  "accessLevel": "public",
  "bureauCode": [
    "010:12"
  ],
  "contactPoint": {
    "@type": "vcard:Contact",
    "fn": "Integrated Modeling &Prediction Division",
    "hasEmail": "mailto:gs-w-model-data-management@usgs.gov"
  },
  "description": "This data set is a national map of predicted probability of\nnitrate contamination of shallow ground waters based on a\nlogistic regression (LR) model.  The LR model was used to\npredict the probability of nitrate contamination exceeding 4\nmg/L in predominantly shallow, recently recharged ground waters\nof the United States.\n\t\t\nThe model contains variables representing (1) nitrogen (N)\nfertilizer loading, (2) percent cropland-pasture, (3) natural\nlog of human population density, (4) percent well-drained soils,\n(5) depth to the seasonally high water table, and (6) presence\nor absence of unconsolidated sand and gravel aquifers.  Observed\nand average predicted probabilities associated with deciles of\nrisk are well correlated (r2 = 0.875), indicating that the LR\nmodel fits the data well.  The likelihood of nitrate\ncontamination is greater in areas with high N loading and\nwell-drained surficial soils over unconsolidated sand and\ngravels.  The LR model correctly predicted the status of nitrate\ncontamination in 75 percent of wells in a validation data set\nfrom the National Water-Quality Assessment (NAWQA) program.\nConsidering all wells used in both calibration and validation,\nobserved median nitrate concentration increased from 0.24 to\n8.30 mg/L as the mapped probability of nitrate exceeding 4 mg/L\nincreased from less than or equal to 0.17 to greater than 0.83.",
  "distribution": [
    {
      "@type": "dcat:Distribution",
      "accessURL": "https://doi.org/10.5066/P9QXWEE9",
      "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.d1c19241-8e46-40ee-a0b1-1ab3fc0c7bf3.xml",
      "format": "XML",
      "mediaType": "text/xml",
      "title": "Original Metadata"
    }
  ],
  "identifier": "http://datainventory.doi.gov/id/dataset/USGS_d1c19241-8e46-40ee-a0b1-1ab3fc0c7bf3",
  "keyword": [
    "Ground water",
    "Ground water contamination",
    "Ground water pollution",
    "Ground water susceptibility",
    "NAWQA",
    "National Water-Quality Assessment Program",
    "Nitrate",
    "Nutrients",
    "USGS:d1c19241-8e46-40ee-a0b1-1ab3fc0c7bf3",
    "environment",
    "geoscientificInformation",
    "inlandWaters"
  ],
  "modified": "2020-11-17T00:00:00Z",
  "publisher": {
    "@type": "org:Organization",
    "name": "U.S. Geological Survey"
  },
  "spatial": "-129.839567, 21.217696, -64.113097, 51.784295",
  "theme": [
    "geospatial"
  ],
  "title": "Probability of nitrate contamination of recently recharged ground waters in the conterminous United States"
}