This geodatabase includes spatial datasets that represent the Mississippian aquifer in the States of Alabama, Illinois, Indiana, Iowa, Kentucky, Maryland, Missouri, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia. The aquifer is divided into three subareas, based on the data availability. In subarea 1 (SA1), which is the aquifer extent in Iowa, data exist of the aquifer top altitude and aquifer thickness. In subarea 2 (SA2), which is the aquifer extent in Missouri, data exist of the aquifer top and bottom aquifer surface altitudes. In subarea 3 (SA3), which is the aquifer area of the remaining States, no altitude or thickness data exist. Included in this geodatabase are: (1) a feature dataset "ds40MSSPPI_altitude_and_thickness_contours that includes aquifer altitude and thickness contours used to generate the surface rasters for SA1 and SA2, (2) a feature dataset "ds40MSSPPI_extents" that includes a polygon dataset that represents the subarea extents, a polygon dataset that represents the combined overall aquifer extent, and a polygon dataset of the Ft. Dodge Fault and Manson Anomaly, (3) raster datasets that represent the altitude of the top and the bottom of the aquifer in SA1 and SA2, and (4) georeferenced images of the figures that were digitized to create the aquifer top- and bottom-altitude contours or aquifer thickness contours for SA1 and SA2. The images and digitized contours are supplied for reference. The extent of the Mississippian aquifer for all subareas was produced from the digital version of the HA-730 Mississippian aquifer extent, (USGS HA-730). For the two Subareas with vertical-surface information, SA1 and SA2, data were retrieved from the sources as described below. 1. The aquifer-altitude contours for the top and the aquifer-thickness contours for the top-to-bottom thickness of SA1 were received in digital format from the Iowa Geologic Survey. The URL for the top was ftp://ftp.igsb.uiowa.edu/GIS_Library/IA_State/Hydrologic/Ground_Waters/ Mississippian_aquifer/mississippian_topography.zip. The URL for the thickness was ftp://ftp.igsb.uiowa.edu/GIS_Library/IA_State/Hydrologic/Ground_Waters/ Mississippian_aquifer/mississippian_isopach.zip Reference for the top map is Altitude and Configuration, in feet above mean sea level, of the Mississipian Aquifer modified from a scanned image of Map 1, Sheet 1, Miscellaneous Map Series 3, Mississippian Aquifer of Iowa by P.J. Horick and W.L. Steinhilber, Iowa Geological Survey, 1973; IGS MMS-3, Map 1, Sheet 1 Reference for the thickness map is Distribution and isopach thickness, in feet, of the Mississipian Aquifer, modified from a scanned image of Map 1, Sheet 2, Miscellaneous Map Series 3, Mississippian Aquifer of Iowa by P.J. Horick and W.L. Steinhilber, Iowa Geological Survey, 1973; IGS MMS-3, Map 1, Sheet 2 2. The altitude contours for the top and bottom of SA2 were digitized from georeferenced figures of altitude contours in U.S. Geological Survey Professional Paper 1305 (USGS PP1305), figure 6 (for the top surface) and figure 9 (for the bottom surface). The altitude contours for SA1 and SA2 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. ArcGIS Desktop: Release 10.2 Redlands, CA: Environmental Systems Research Institute. The raster surfaces were corrected in 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.

This geodatabase includes spatial datasets that represent the Silurian-Devonian aquifers in the States of Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, Ohio, Tennessee, and Wisconsin. Included are: (1) polygon extents; datasets that represent the aquifer system extent, and the entire extent subdivided into subareas, (2) raster datasets for the altitude of the top and bottom surfaces of the entire aquifer (where data are available), and (3) altitude contours used to generate the surface rasters. The digitized contours are supplied for reference. The extent of the Silurian-Devonian aquifers is from the linework of the Silurian-Devonian aquifer extent maps in U.S. Geological Survey U.S. Geological Survey Hydrologic Atlas 730, Chapters J and K, (USGS HA 730-J, -K) and a digital version of the aquifer extent presented in the National Aquifer Code Reference List, available at http://water.usgs.gov/ogw/NatlAqCode-reflist.html , "silurian.zip". The extent was then modified for each subarea: Subarea 1 (sa1): Primarily in Ohio and Indiana, subject of U.S. Geological Survey Professional Paper 1423 B (USGS PP 1423B). Subarea 2 (sa2): In Iowa. Digital data were available from the Iowa Geologic Survey. Subarea 3 (sa3): Remaining area in Illinois, Wisconsin, Michigan, and Kentucky. Extent is that part of the National Aquifer Code Reference List polygon that remained when the areas of sa1 and sa2 were removed. The altitude and thickness contours that were available for each subarea were compiled or generated from georeferenced figures of altitude contours in USGS PP 1423B for sa1, digital data from IAGS for sa2. There were no vertical data for sa3. 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 in 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 Texas Coastal Uplands and Mississippi Embayment aquifer system in the States of Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, 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 (outcrop areas, 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 and thickness contours. The images and digitized contours are supplied for reference. The extent of the Texas Coastal Uplands and Mississippi Embayment aquifer system is derived from the linework in the aquifer system extent maps in U.S. Geological Survey Professional Paper 1416-B (USGS PP 1416-B), plates 11, 13, 15, 16, and 17, and from a digital version of the aquifer extents presented in the U.S. Geological Survey Hydrologic Atlas 730, Chapters E and F. The Texas Coastal Uplands and Mississippi Embayment aquifer system has 6 aquifer subunits, in order from the most surficial to the deepest: A1: Upper Claiborne aquifer, A2: Middle Claiborne aquifer, A3: Lower Claiborne- Upper Wilcox aquifer, A4: Middle Wilcox aquifer, A5: Lower Wilcox aquifer, A6: McNairy-Nacatoch aquifer. The altitude and thickness contours for each available subunit were digitized from georeferenced figures of altitude contours in USGS PP 1416-B, and 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, derives the altitude from the thickness (depth from the land surface), and merges 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 altitude of an overlying layer.

This geodatabase includes spatial datasets that represent the Southeastern Coastal Plain aquifer system in the States of Alabama, Georgia, Mississippi, South Carolina, and Tennessee. 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) 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 and thickness contours. The images and digitized contours are supplied for reference. The extent of the Southeastern Coastal Plain aquifer system is derived the linework in the Southeastern Coastal Plain aquifer system extent maps in a digital version of the aquifer extent presented in the Groundwater Atlas of the United States (the U.S. Geological Survey Hydrologic Atlas HA-730-F, -730-G, and -730-K. The Southeastern Coastal Plain aquifer system has 4 aquifer subunits, in order from the most surficial to the deepest: A1: Chickasawhay River aquifer, A2: Pearl River Aquifer, A3: Chattahoochee River Aquifer, and A4: Black Warrior River Aquifer. The altitude and thickness contours for each available subunit were digitized from georeferenced figures of altitude contours in U.S. Geological Survey Profession Paper 1410-B, (USGS PP 1410-B), and 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 "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. The surface rasters were corrected for the areas where the altitude of an underlying layer of the aquifer exceeded altitude of an overlying layer.

This geodatabase includes spatial datasets that represent the Southeastern Coastal Plain aquifer system in the States of Alabama, Georgia, Mississippi, South Carolina, and Tennessee. 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) 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 and thickness contours. The images and digitized contours are supplied for reference. The extent of the Southeastern Coastal Plain aquifer system is derived the linework in the Southeastern Coastal Plain aquifer system extent maps in a digital version of the aquifer extent presented in the Groundwater Atlas of the United States (the U.S. Geological Survey Hydrologic Atlas HA-730-F, -730-G, and -730-K. The Southeastern Coastal Plain aquifer system has 4 aquifer subunits, in order from the most surficial to the deepest: A1: Chickasawhay River aquifer, A2: Pearl River Aquifer, A3: Chattahoochee River Aquifer, and A4: Black Warrior River Aquifer. The altitude and thickness contours for each available subunit were digitized from georeferenced figures of altitude contours in U.S. Geological Survey Profession Paper 1410-B, (USGS PP 1410-B), and 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 "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. The surface rasters were corrected for the areas where the altitude of an underlying layer of the aquifer exceeded altitude of an overlying layer.

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 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 data set represents the extent of the Pennsylvanian aquifers in the states of Pennsylavania, West Virginia, Ohio, Virginia, Kentucky, North Carolina, Tennessee, Alabama, Illinois, Indiana, and Michigan.

This data set represents the extent of the Pennsylvanian aquifers in the states of Pennsylavania, West Virginia, Ohio, Virginia, Kentucky, North Carolina, Tennessee, Alabama, Illinois, Indiana, and Michigan.

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.