{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Erick Burns", "hasEmail": "mailto:eburns@usgs.gov"}, "description": "The obtop_f grid represents the modeled elevation of the top of the Overburden geomodel unit \nat a 500 foot resolution. It is one grid of a geomodel that consists of eleven grids and a spatial \nextent polygon shapefile.  As part of a U.S. Geological Survey Groundwater Resources \nProgram study, a three-dimensional geomodel was constructed for approximately 53,000 \nmi2 of the Columbia Plateau in Washington, Oregon, and Idaho. This geomodel was \nconstructed to define the general aquifer system geometry for use in a regional numerical \ngroundwater flow model. Simplifications and assumptions consistent with this ultimate \ngoal and the uncertainty in the available data were made. The geomodel units consist of \nMiocene age Columbia River Basalt Group strata and younger alluvial overburden covering \napproximately 44,000 mi2. Data were compiled from numerous databases and detailed \nstudies completed during the past three decades. These data include stratigraphic \ninterpretations made on more than 13,000 wells and a contiguous compilation of surficial \ngeology and structural features spanning the study area. These data were simplified and \nused to construct piecewise-smooth trend surfaces that represent upper and lower \nsubsurface geomodel unit boundaries in this complex folded and faulted terrain.  The \nsmoothness of the surfaces implicitly represents uncertainty in prediction of each surface \nresulting from data gaps, errors in borehole interpretations, errors in mapped contact \nlocations, and uncertainty in the shape of the paleo-surface upon which flood basalts \nwere emplaced. Using a rule-based algorithm, surfaces were then recombined to construct \na fully three-dimensional model with a 500-foot grid resolution that is consistent with the \ndata and for which error estimates may be made. The modeling process yielded improved \nestimates of unit volumes, refinement of location of large structural features, and \nidentification of features that may be important for ongoing groundwater studies.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9UZTNZD", "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.94c63be1-474b-44e0-bdaf-136464cce802.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_94c63be1-474b-44e0-bdaf-136464cce802", "keyword": ["CPRAS", "Columbia Plateau", "Columbia Plateau Regional Aquifer System", "Columbia River Basin", "Idaho", "Oregon", "Pacific Northwest", "USGS:94c63be1-474b-44e0-bdaf-136464cce802", "Washington", "geomodel", "inlandWaters", "overburden"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-121.844957854, 44.261075488, -115.367389272, 48.419366654", "theme": ["geospatial"], "title": "Modeled Top of the Overburden Geomodel Unit (obtop_f)"}