{"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 recharge\nvalues for the Tillman terrace and alluvial aquifer in\nsouthwestern Oklahoma. The Tillman terrace and alluvial aquifer\nencompasses the unconsolidated terrace deposits and alluvium\nassociated with the North Fork of the Red River and the Red\nRiver 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.\nA recharge value of 2.87 inches per year was used in the\nground-water flow model and in this data set. The recharge\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 recharge used in the\nmodel and presented in this data set are not precise, but are\nwithin a reasonable range when compared to independently\ncollected data.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P9GE5L6E", "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.9a95945c-9f74-4161-bdf3-966f381c366d.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_9a95945c-9f74-4161-bdf3-966f381c366d", "keyword": ["Tillman alluvial and terrace aquifer", "Tillman alluvial aquifer", "Tillman aquifer", "Tillman terrace and alluvial aquifer", "Tillman terrace aquifer", "USGS:9a95945c-9f74-4161-bdf3-966f381c366d", "alluvial and terrace aquifer", "alluvial aquifer", "alluvial deposit", "aquifers", "environment", "geoscientificInformation", "ground water", "ground-water recharge", "ground-water vulnerability", "groundwater", "groundwater vulnerability", "inlandWaters", "recharge", "recharge rate", "terrace and alluvial aquifer", "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"}