This geodatabase includes spatial datasets that represent the High Plains aquifer in the States of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Included are: (1) polygon extents; datasets that represent the aquifer system extent, (2) raster datasets for the altitude of the top and bottom surfaces of the High Plains aquifer, (3) altitude contours of the top surface and of the bottom surface used to generate the surface rasters. The altitude contours are supplied for reference. The extent of the High Plains aquifer is from the digital dataset U.S. Geological Survey Data Series 543 (USGS DS 543), and as a references, the digital version of the aquifer extent presented in the Groundwater Atlas of the United States (the U.S. Geological Survey Hydrologic Atlas 730-D, -E, and -C, (USGS HA 730-D, -E, -C). The altitude contours for the top surface of the High Plains aquifer are from digital datasets of U.S. Geological Survey Open-File Report 99-263 (USGS OFR 99-263), using the 1980 water-level data. The altitude contours for the bottom surface of the High Plains aquifer are from the U.S. Geological Survey Open-File Report 98-393 (USGS OFR 98-393). The altitude of the bottom surface, or base, was originally from the High Plains Regional Aquifer-System Analysis study. The resultant top and bottom altitude values were interpolated into surface rasters within a GIS using tools that create hydrologically correct surfaces from contour data, derive the altitude from the thickness (depth from the land surface), and merge the subareas into a single surface. The primary tool was an enhanced version of "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. The raster surfaces were corrected for the areas where the altitude of an underlying layer of the aquifer exceeded the altitude of an overlying layer.

This geodatabase includes spatial datasets that represent the Basin and Range basin-fill aquifers in the States of Arizona, California, Idaho, Nevada, New Mexico, Oregon, and Utah. Included are: (1) polygon extents; datasets that represent the aquifer system extent, the entire extent subdivided into subareas or subunits, and any polygon extents of special interest (outcrop areas, no data available, areas underlying other aquifers, anomalies, for example), (2) contours: thickness contours used to generate the surface rasters in subarea 4 (Arizona), (3) modified source raster datasets for subareas 1 and 3, (4) corrected altitudes of top and bottom surface rasters of the entire aquifer. The thickness contours and modified surface rasters are supplied for reference. The extent of the Basin and Range basin-fill aquifer is from the linework of the Basin and Range aquifer extent maps in U.S. Geological Survey Hydrologic Atlas 730 Chapters B and C, and a digital version of the aquifer extent presented in the Groundwater Atlas of the United States (the U.S. Geological Survey Hydrologic Atlas. The Basin and Range basin-fill aquifer has no aquifer subunits, but is defined by five subareas: 1. Subarea 1 is the area that overlies the Basin and Range Carbonate aquifer, which was the subject of U.S. Geological Survey Scientific Investigations Report 2010-5193 (USGS SIR 2010-5193). 2. Subarea 2 is the area of a different aquifer system, which is set to null for use within the Basin and Range basin-fill aquifer from U.S. Geological Survey Principal Aquifers, 2003 (USGS Circular 1323, Figure 2) 3. Subarea 3 is the area of the Basin and Range basin-fill aquifer that was the subject of U.S. Geological Survey Geophysical Map 1012 (USGS GP-1012) and not covered by USGS SIR 2010-5193 or the Basin and Range basin-fill aquifer in Arizona, Arizona Geological Survey, Digital Geological Map 52 (AZGS DGM-52). Top of aquifer is land surface. USGS GP-1012 dataset is depth from land surface to basin bottom. 4. Subarea 4 is the area of the 01BSNRGB aquifer in Arizona, (AZGS DGM-52) 5. Subarea 5 areas are in the Basin and Range basin-fill extent areas that do not have top/bot defined. The resultant top and bottom surface rasters for each subarea were merged into surface rasters of the top and bottom of the entire Basin and Range basin-fill aquifer within a GIS using tools that create hydrologically correct surfaces from contour data, deriving the altitude from the thickness (depth from the land surface), and merging the subareas into a single surface. The primary tools were a version of "Topo to Raster", and "Mosaic to New Raster" used in ArcGIS, ArcMap, Esri 2014.

This data set represents the extent of the High Plains aquifer in the states of South Dakota, Wyoming, Nebraska, Colorado, Kansas, New Mexico, Oklahoma, and Texas. This aquifer extent has been superceded by DS543 https://water.usgs.gov/GIS/metadata/usgswrd/XML/ds543.xml

This geodatabase includes spatial datasets which represent the Lower Cretaceous aquifer system in the States of Iowa, Kansas, Minnesota, Montana, Nebraska, North Dakota, South Dakota, and Wyoming. Included are: (1) a polygon dataset that represents the aquifer system extent, (2) raster datasets for the altitude of each aquifer subarea, (3) altitude and thickness contours (plus thickness fault lines) used to generate the surface rasters, (4) georeferenced images of the figures that were digitized to create the altitude and thickness contours. The images and digitized contours are supplied for reference. The extent of the Lower Cretaceous aquifer for all subareas was produced from the linework of the Lower Cretaceous aquifers maps in U.S. Geological Survey Professional Paper 1414-E (USGS PP 1414-E) Plate 6, U.S. Geological Survey Water-Resources Investigations Report 84-4153 (USGS WRIR 84-4153) Plate 1, and the U.S. Geological Survey Hydrologic Atlas 730 (USGS HA-730). A digital version of the HA-730 Lower Cretaceous aquifer extent is presented in the Groundwater Atlas of the United States (the U.S. Geological Survey Hydrologic Atlas 730-D,(USGS HA 730-D), 730-I (USGS HA 730-I), and 730-J (USGS HA 730-J. The Lower Cretaceous Aquifer System has 4 aquifer subareas: (SA1) Great Plains aquifer, (SA2) Iowa aquifer, (SA3) Minnesota aquifer, and (SA4) Northern Great Plains aquifer. The altitude lines for the top of SA1 and SA4 were digitized from georeferenced figures of altitude contours in USGS PP 1414-E Plate 4 and USGS PP 1402-B Plate 1. Altitude lines for the top of SA3 were digitized from WRIR 84-4153 Figure 5. The top of SA2 was derived from the thickness contours for SA2, USGS PP 1414-E Figure 16. Areas of overlap between subareas were deleted, based on available original data. The altitude values and thickness values were interpolated into surface rasters within a GIS using tools that create hydrologically correct surfaces from contour data, derives the altitude from the thickness (depth from the land surface), and merge the subareas into a single surface. The primary tool was "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. The raster surfaces were corrected for the areas where the altitude of the top of the aquifer exceeded the land surface, and where the bottom of an aquifer exceeded the altitude of the corrected top of the aquifer. For a more detailed description of the processes used by the data compiler, please see the Supplementary Information section.

The Western Interior Plains aquifer system is located in parts of Arkansas, Colorado, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming and covers an area of more than 220,800 square miles. The thickness of the aquifer system ranges from 500 feet in eastern Colorado (HA 730-D) to as much as 10,000 feet in western Oklahoma (PP_1414B). This aquifer system consists of water-bearing dolostone, limestone, and shale and overlies the basement confining unit in the western part of the Interior Plains physiographic division. This aquifer system consists of the upper aquifer unit (A1), a middle confining unit, and the lower aquifer unit (A2). The aquifer system is overlain by the Western Interior Plains confining system and is underlain by the Basement confining unit (PP_1414B). This product provides source data for the Western Interior Plains aquifer system framework, including: Georeferenced images: 1. i_63WIP_A1_top.tif: Digitized figure of extent and altitude contour lines representing the top of the Western Interior Plains aquifer system upper unit. The original figure was from PP_1414B plate 6. 2. i_63WIP_A1_bot.tif: Digitized figure of altitude contour lines of the top of the confining unit between the upper and lower units of the Western Interior Plains aquifer system. This figure was used to construct the bottom contour lines of the upper aquifer unit. The original figure was from PP_1414B plate 5. 3. i_63WIP_A2_top.tif: Digitized figure of extent and altitude contour lines representing the top of the Western Interior Plains aquifer system lower unit. The original figure was from PP_1414B plate 4. 4. i_63WIP_A2_bot.tif: Digitized figure of altitude contour lines of the top of the basement confining unit of the Western Interior Plains aquifer system. This figure was used to construct the bottom contour lines of the lower aquifer unit. The original figure was from PP_1414B plate 3. Extent shapefiles: 1. p_63WIP.shp: Polygon shapefile containing the areal extent of the Western Interior Plains aquifer system sourced from PP_1414B plates 4 and 6. The extent file contains the upper and lower subunits A1 and A2. Contour line shapefiles: 1. c_63WIP_A1_top.shp: Contour line dataset containing altitude values, in feet reference to National Geodetic Vertical Datum of 1929 (NGVD29), of the top of the Western Interior Plains aquifer system upper unit. These data were used to create the ra_63WIP_A1_top.tif dataset. 2. c_63WIP_A1_bot.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the bottom of the Western Interior Plains aquifer system upper unit. These data were used to create the ra_63WIP_A1_bot.tif dataset. 3. c_63WIP_A2_top.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the top of the Western Interior Plains aquifer system lower unit. These data were used to create the ra_63WIP_A2_top.tif dataset. 4. c_63WIP_A2_bot.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the bottom of the Western Interior Plains aquifer system lower unit. These data were used to create the ra_63WIP_A2_bot.tif dataset. Altitude raster files: 1. ra_63WIP_A1_top.tif: Altitude raster dataset of the top of the Western Interior Plains aquifer system upper unit. The altitude values are in meters reference to North American Vertical Datum of 1988 (NAVD88). This raster was interpolated from contour line shapefile c_63WIP_A1_top.shp. 2. ra_63WIP_A1_bot.tif: Altitude raster dataset of the bottom of the Western Interior Plains aquifer system upper unit. The altitude values are in meters reference to NAVD88. This raster was interpolated from contour line shapefile c_63WIP_A1_bot.shp. 3. ra_63WIP_A2_top.tif: Altitude raster dataset of the top of the Western Interior Plains aquifer system lower unit. The altitude values are in meters reference to NAVD88. This raster was interpolated from contour line shapefile c_63WIP_A2_top.shp. 4.

This data set consists of digital base of aquifer elevation contours for the High Plains aquifer in the central United States. The High Plains aquifer extends from south of 32 degrees to almost 44 degrees north latitude and from 96 degrees 30 minutes to almost 104 degrees west longitude. The outcrop area covers 174,000 square miles and is present in Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. This digital data set was created by digitizing the base of aquifer elevation contours from a 1:1,000,000 base map created by the U.S. Geological Survey High Plains RASA project (Gutentag, E.D., Heimes, F.J., Krothe, N.C., Luckey, R.R., and Weeks, J.B., 1984, Geohydrology of the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Professional Paper 1400-B, 63 p.) The data should not be used at scales larger than 1:1,000,000.

Several pre-existing datasets that characterize portions of the Northern High Plains aquifer base were merged together in order to define the entire base of the Northern High Plains aquifer. This digital dataset consists of the aquifer base elevation contours (100-foot contour interval) for the northern portion of the High Plains aquifer in the central United States. The boundaries were chosen to simplify boundary conditions for a computer simulation model being used for a hydrologic study of the Northern High Plains.

This digital data set consists of faults for the High Plains aquifer in the central United States. The High Plains aquifer extends from south of 32 degrees to almost 44 degrees north latitude and from 96 degrees 30 minutes to 106 degrees west longitude. The outcrop area covers 174,000 square miles and is present in Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. This digital data set was created by digitizing the faults from a 1:1,000,000-scale base map created by the U.S. Geological Survey High Plains Regional Aquifer-System Analysis (RASA) project (Gutentag, E.D., Heimes, F.J., Krothe, N.C., Luckey, R.R., and Weeks, J.B., 1984, Geohydrology of the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Professional Paper 1400-B, 63 p.) The data are not intended for use at scales larger than 1:1,000,000.

This data set represents the extent of the Paleozoic aquifers in the states of South Dakota, Wyoming, and Montana.

This geodatabase contains the spatial datasets that represent the Edwards-Trinity aquifer system in the States of Arkansas, Oklahoma, and Texas. Included are: (1) polygon extents; datasets that represent the aquifer system extent, the entire extent subdivided into subareas or subunits, and any polygon extents of special interest (no data available, areas underlying other aquifers, anomalies, for example), (2) raster datasets for the altitude of each aquifer subarea or subunit, (3) altitude, and/or if applicable, thickness contours used to generate the surface rasters, (4) georeferenced images of the figures that were digitized to create the altitude or thickness contours. The images and digitized contours are supplied for reference. The extent of the Edwards-Trinity aquifer system encompasses all subunits. It is delineated from the linework of the Edwards-Trinity aquifer system extent and outcrop maps of the U.S. Geological Survey Hydrologic Atlas 730-E (USGS HA 730-E) , available at http://water.usgs.gov/ogw/NatlAqCode-reflist.html. Included are the "no data available" extent polygons where there were no altitude data available for the bottom surface of the Edwards-Trinity aquifer system. These were digitized from USGS HA-730-E, figure 81, and U.S. Geological Survey Water-Resources Investigations Report 85-4116 (USGS WRIR 85-4116), plate 9, and U.S. Geological Survey Water-Resources Investigations Paper 91-4071 (USGS WRIR 91-4071), plate 1. The Edwards-Trinity aquifer system has three aquifer subunits, but for the purposes of this geodatabase only the ultimate top and bottom surface rasters are published. The altitudes for the top surface raster are from georeferenced images of altitude contours from USGS HA-730-E, figures 84, 98 and 114, and USGS WRIR 85-4116, plate 8. In the areas where the Edwards-Trinity top surface underlies the Pecos River alluvial aquifer (USGS HA 730-E, Pecos River Basin alluvial aquifer), and the High Plains aquifer (see USGS HA 730-E, High Plains aquifer), the altitude of the bottom those two aquifers is the top of the Edwards-Trinity aquifer system. The altitudes of the bottom surface raster are from georeferenced images of altitude contours from USGS HA-730-E figure 81, USGS WRIR 85-4116 plate 9, and USGS WRIR 91-4071 plate 1. The altitude contours were interpolated into surface rasters within a GIS using tools that create hydrologically correct surfaces from contour data, derives the altitude from the thickness (depth from the land surface) if necessary, and merges the subareas into a single surface. The primary tool was "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. ArcGIS Desktop: Release 10.2 Redlands, CA: Environmental Systems Research Institute.