{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Carol J. Becker", "hasEmail": "mailto:cjbecker@usgs.gov"}, "description": "This data set consists of digital polygons of constant hydraulic\nconductivity values for the Tillman terrace and alluvial aquifer\nin southwestern Oklahoma. The Tillman terrace and alluvial\naquifer encompasses the unconsolidated terrace deposits and\nalluvium associated with the North Fork of the Red River and the\nRed River in the western half of Tillman County. These sediments\nconsist of discontinuous layers of clay, sandy clay, sand, and\ngravel. The aquifer extends over an area of 285 square miles and\nis used for irrigation and domestic purposes. Granite and the\nHennessey Formation outcrop in northern parts of the aquifer\nwhere alluvial deposits are absent. These outcrops were included\nas part of the aquifer in a thesis in which the ground-water\nflow in the aquifer was modeled.\nAn average hydraulic conductivity value of 92.5 feet per day was\nused for both the terrace and alluvial deposits in this data set\nand was reported in the thesis. The hydraulic conductivity\npolygons were derived from two sources. The outer polygon\nrepresenting the outer shell of a model grid for a ground-water\nflow model of the Tillman terrace and alluvial aquifer was\ndigitized from a paper map in a thesis at a scale of 1:249,695.\nPolygons and lines representing geologic contacts were extracted\nfrom a published digital surficial geology data set based on a\nscale of 1:250,000. Small polygons along the eastern boundary of\nthe aquifer were created when the outer polygon of the model\ngrid and the geology polygons and lines were combined. These\nsmall polygons represent geologic units other than the Tillman\nterrace and alluvial aquifer within the model grid. Three small\npolygons representing outcrops of granite and the Hennessey\nFormation in the northern parts of the aquifer also were\nextracted from the digital surficial geology data set.\nGround-water flow models are numerical representations that\nsimplify and aggregate natural systems. Models are not unique;\ndifferent combinations of aquifer characteristics may produce\nsimilar results. Therefore, values of hydraulic conductivity\nused in the model and presented in this data set are not\nprecise, but are within a reasonable range when compared to\nindependently collected data.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9PYPM0O", "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.771b04b4-5d88-43f0-ac01-0c076cf6dc30.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_771b04b4-5d88-43f0-ac01-0c076cf6dc30", "keyword": ["Tillman alluvial and terrace aquifer", "Tillman alluvial aquifer", "Tillman aquifer", "Tillman terrace and alluvial aquifer", "Tillman terrace aquifer", "USGS:771b04b4-5d88-43f0-ac01-0c076cf6dc30", "alluvial aquifer", "alluvial deposit", "alluvium", "aquifers", "coefficent of permeability", "environment", "geoscientificInformation", "ground water", "ground-water vulnerability", "groundwater", "groundwater vulnerability", "hydraulic conductivity", "inlandWaters", "permeability", "permeability coefficent", "terrace aquifer", "terrace deposit"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-99.2286, 34.1912, -98.9482, 34.6411", "theme": ["geospatial"], "title": "Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma"}