{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Nebraska Water Science Center", "hasEmail": "mailto:dc_ne@usgs.gov"}, "description": "The U.S. Geological Survey (USGS), in cooperation with the Lewis and Clark Natural Resources District \n(NRD), Lower Elkhorn NRD, Lower Loup NRD, Lower Platte North NRD, Lower Niobrara NRD, Middle \nNiobrara NRD, Upper Elkhorn NRD, and Upper Loup NRD, have agreed to cooperatively study water \nresources from prior to the beginning of irrigation development to 2005 in the Elkhorn-Loup Model (ELM) \narea using a ground-water-flow model.  The ELM area covers approximately 30,800 square miles, and \nextends from the Niobrara River in the north to the Platte River in the south.  The western boundary of \nthe ELM area coincides with the western boundary of the Middle Niobrara, Twin Platte, and Upper Loup \nNRDs; the eastern boundary coincides with the approximate location of the westernmost extent of \nglacial till in eastern Nebraska. The initial ground-water-flow model was constructed with a single layer \nvertically to represent the aquifers of the Tertiary-age Ogallala Group and Quaternary-age alluvial deposits, \nwith a uniform node spacing of 2 miles. The model will be calibrated to measured ground-water levels and \nestimated ground-water discharge to streams for the pre-ground-water development period (approximately \n1940) and the simulation of the 1940-2005 period will be calibrated to measure ground-water level changes. \nThe study results will assist Nebraska Department of Natural Resources and the NRDs in the ELM area to \ndevelop long-term strategies for managing hydrologically connected waters.\n\t\t\t\nThis dataset is one of three geospatial datasets that together revise previously published maps of the \nconfiguration of the base of the principal aquifer and of the geologic units that form the base of the principal \naquifer in the study area; the revisions to the base-of-aquifer altitude are based on currently available or \nreinterpreted geologic logs of test holes and selected registered wells. The principal aquifer is the High \nPlains aquifer except in the northeast part of the model area, where the principal aquifer is an unnamed \nalluvial aquifer.\n\t\t\t\nThis dataset identifies and delimits approximately the extent of the geologic units forming the base of the \nprincipal aquifer and the areas where the base of principal aquifer surface is not well defined. Ambiguity \nin the calculated base of aquifer existed wherever this calculated base-of-aquifer altitude was above the \nmapped land surface. The calculated base of aquifer was above  the mapped land surface either because \nof inaccuracy in the mapped land surface or base of aquifer calculation or because the principal aquifer \nwas thin or not present.", "distribution": [{"@type": "dcat:Distribution", "accessURL": "https://doi.org/10.5066/P94S38MW", "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.9d5fdfa8-11cb-41c9-a3a0-ad48a48ea290.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_9d5fdfa8-11cb-41c9-a3a0-ad48a48ea290", "keyword": ["Aquifer characteristics", "Brule Formation", "Chadron Formation", "Elkhorn-Loup Model Area", "Geohydrologic units", "High Plains aquifer", "Lower Tertiary", "Niobrara Formation", "Ogallala aquifer", "Pierre Shale", "USGS:9d5fdfa8-11cb-41c9-a3a0-ad48a48ea290", "Upper Cretaceous", "White River Group", "aquifer base", "geoscientificInformation", "inlandWaters"], "modified": "2020-11-17T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-102.128248, 40.598895, -97.274685, 42.925235", "theme": ["geospatial"], "title": "Digitial map of geologic units forming the base of the principal aquifer and areas where the base of aquifer is not well defined, Elkhorn-Loup Model area, north-central Nebraska"}