Entry_ID: (required)
Entry_Title: Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands
Group: Data_Set_Citation
  Originator(s): U.S. Geological Survey
  Title: Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands
  Publication_Date: 200310
  Publication_Place: Madison, WI, USA
  Publisher: U.S. Geological Survey
  Edition: Version 1.0
  URL: <http://nationalatlas.gov/atlasftp.html>
End_Group
Keyword: Geoscientific information
Group: Temporal_Coverage
  Start_date: 200310
  Stop_date: 200310
End_Group
Data_Set_Progress: Complete
Group: Spatial_Coverage
  Southernmost_Latitude: 24.518322
  Northernmost_Latitude: 49.385619
  Westernmost_Longitude: -124.755908
  Easternmost_Longitude: -66.939561
End_Group
Location: Alabama
Location: Arizona
Location: Arkansas
Location: California
Location: Colorado
Location: Connecticut
Location: Delaware
Location: District of Columbia
Location: Florida
Location: Georgia
Location: Hawaii
Location: Idaho
Location: Illinois
Location: Indiana
Location: Iowa
Location: Kansas
Location: Kentucky
Location: Louisiana
Location: Maine
Location: Maryland
Location: Massachusetts
Location: Michigan
Location: Minnesota
Location: Mississippi
Location: Missouri
Location: Montana
Location: Nebraska
Location: Nevada
Location: New Hampshire
Location: New Jersey
Location: New Mexico
Location: New York
Location: North Carolina
Location: North Dakota
Location: Ohio
Location: Oklahoma
Location: Oregon
Location: Pennsylvania
Location: Rhode Island
Location: South Carolina
Location: South Dakota
Location: Tennessee
Location: Texas
Location: Utah
Location: Vermont
Location: Virginia
Location: Washington
Location: West Virginia
Location: Wisconsin
Location: Wyoming
Location: Puerto Rico
Location: U.S. Virgin Islands
Location: United States
Group: Data_Resolution
  Latitude_Resolution: 0.000278
  Longitude_Resolution: 0.000278
End_Group
  Access_Constraints: None
  Use_Constraints: None.  Acknowledgment of the Ground Water Atlas of the United States and (or) the National Atlas of the United States of America would be appreciated in products derived from these data.
Originating_Center: (required)
Group: Data_Center
  Data_Center_Name: U.S. Geological Survey, Water Resources Division
Group: Data_Center_Contact
  Last_name: U.S. Geological Survey, Water Resources Division
  First_name: N/A
  Phone: 1-800-426-9000
  Group: Address
    12201 Sunrise Valley Drive
    Reston, VA 20192
    USA
  End_Group
End_Group
End_Group
  Storage_Medium: SDTS, Arc/GIS 8.0.1, and ESRI Shapefile format. 
Group: Distribution
  Distribution_Media: online
  Distribution_Format : ESRI Personal Geodatabase
  Fees: There is no charge for the map layer.
End_Group
Group: Distribution
  Distribution_Media: online
  Distribution_Format : ESRI Shapefile
  Fees: There is no charge for the map layer.
End_Group
Group: Distribution
  Distribution_Media: online
  Distribution_Format : SDTS
  Fees: There is no charge for the map layer.
End_Group
Group: Reference
  Citation_Information:
    Originator: U.S. Geological Survey
    Publication_Date: 200209
    Title: Aquifers of Alluvial and Glacial Origin
    Publication_Information:
      Publication_Place: Reston, VA
      Publisher: National Atlas of the United States
    Online_Linkage: <http://nationalatlas.gov/atlasftp.html>


End_Group
Group: Summary
  These data are intended for use in publications, at a scale of 1:2,500,000
  or smaller.  Due to the small scale, the primary intended use is for
  regional and national data display and analysis, rather than specific
  local data analysis.
  
  This map layer contains the shallowest principal aquifers of the
  conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin
  Islands, portrayed as polygons.  The map layer was developed as part of
  the effort to produce the maps published at 1:2,500,000 in the printed
  series "Ground Water Atlas of the United States".  The published maps
  contain base and cultural features not included in these data.  This is a
  replacement for the July 1998 map layer called Principal Aquifers of the
  48 Conterminous United States.
  
  The Ground Water Atlas of the United States (GWA) chapters include
  additional information that may be relevant to the use of this map layer,
  such as maps of alluvial and glacial aquifers that overlie the aquifers in
  this map layer, as well as other information described below.
  
  The areal extent of the aquifers, as shown in this map layer, represents
  the area in which a named aquifer is the shallowest of the principal
  aquifers.  These aquifer areas are not necessarily the only areas in which
  ground water can be withdrawn, for two reasons:  1) The aquifers shown may
  have a larger areal extent than is represented here.  The boundaries in
  this map layer generally represent an interpretation of the surface
  location (outcrop), or near-surface location (shallow subcrop) of the
  uppermost principal aquifer for the area.  An aquifer may extend beyond
  the area shown, but be overlain by one or more other aquifers, and (or)
  low-permeability material.  2) There may be areas of water-bearing
  surficial material not shown in this map layer.  Major alluvial aquifers
  that occur along main watercourses are not shown.  Significant
  unconsolidated sand and gravel aquifers, that are not indicated in this
  map layer but are important sources of water, may occur locally in
  glaciated regions.  The user of this map layer is advised that to get
  complete information regarding areas that serve as sources of water, more
  information about surficial aquifers needs to be obtained, particularly in
  glaciated areas.
  
  This map layer was constructed by combining data created for or from the
  regional GWA chapters.  Minor aquifers that are important local sources of
  water were mapped in some regions, so the regional maps in the GWA may
  show more detail than this map layer.  The data were reviewed, adjusted,
  and published based on new information provided by national, State, and
  local scientists.  The juxtaposition of regionally mapped aquifers has led
  to some instances where an aquifer outcrop or shallow subcrop is bounded
  by a State line.  This is a result of the regional mapping and national
  categorization methods used and is not meant to imply a hydrogeologic
  change coincident with a State boundary.
  
  The aquifer outcrop and shallow subcrop boundaries represent broad,
  regional categories and should not be interpreted as site-specific.
  Comments regarding the names of aquifers or the hydrogeologic
  interpretation of the aquifers can be directed to the U.S. Geological
  Survey, Water Resources Division, Office of Ground Water,
  ogw_webmaster@usgs.gov.
  
  This map layer was used as part of the effort to publish a 1:5,000,000-
  scale 'Principal Aquifers' map in the National Atlas of the United States
  of America series of printed maps.  The printed map can be considered  a
  representation of this map layer with the exceptions of: the smaller
  scale, slight differences in the coastline due to generalization, base and
  cultural information, and delineation of the glacial-deposit area.
  
  These data were developed in conjunction with the publication of the GWA.
  For documentation purposes, areas are referred to by their corresponding
  GWA chapter letter, or by State.  This list shows the relationship between
  State names and GWA chapters:
  >HA 730-B        Segment 1-California, Nevada
  >HA 730-C        Segment 2-Colorado, Utah, New Mexico, Arizona
  >HA 730-D        Segment 3-Kansas, Missouri, Nebraska
  >HA 730-E        Segment 4-Texas, Oklahoma
  >HA 730-F        Segment 5-Arkansas, Louisiana, Mississippi
  >HA 730-G        Segment 6-Alabama, Florida, Georgia, South Carolina
  >HA 730-H        Segment 7-Idaho, Oregon, Washington
  >HA 730-I        Segment 8-Montana, North Dakota, South Dakota, Wyoming
  >HA 730-J        Segment 9-Iowa, Michigan, Minnesota, Wisconsin
  >HA 730-K        Segment 10-Illinois, Indiana, Kentucky, Ohio, Tennessee
  >HA 730-L        Segment 11-Delaware, Maryland, New Jersey, North
  >                           Carolina, Pennsylvania, Virginia, West
  >                           Virginia
  >HA 730-M        Segment 12-Connecticut, Maine, Massachusetts, New
  >                           Hampshire, New York, Rhode Island, Vermont
  >HA 730-N        Segment 13-Alaska, Hawaii, Puerto Rico, and the U.S.
  >                           Virgin Islands
  Refer to <http://capp.water.usgs.gov/gwa/gwa.html> for a graphic depiction
  of the GWA chapter regions, as well as more information about the GWA.
  
  It may be helpful to refer to the printed GWA chapters when using the
  Data, however, there are significant differences between this national
  map layer and the printed chapters.  Because the GWA regional chapters
  were written by different authors, there were areas of different
  interpretations and category delineations, aquifer names, etc., that
  became apparent when combining the regions.
  
  The following listings show the differences between aquifer names in the
  GWA chapters and the aq_name and aq_code used in this map layer.  See the
  Entity and Attribute Information section for definitions of the data
  attributes.
  
  >GWA chapter HA 730-B
  >Name from fig 11, page B4     aq_code-aq_name
  >____________________________________________________________
  >Basin and Range volcanic-     601-Southern Nevada
  >rock aquifers                     volcanic-rock aquifers
  >
  >Coastal Basins aquifers       103-California Coastal Basin
  >                                  aquifers
  >
  >Northern California Basin     104-Pacific Northwest
  >fill aquifers                     basin-fill aquifers
  >
  >
  >GWA chapter HA 730-C
  >Name from fig 11, page C4
  >____________________________________________________________
  >Names and categories the same
  >
  >
  >GWA chapter HA 730-D
  >Name from fig 5, page D4      aq_code-aq_name
  >____________________________________________________________
  >Mississippi embayment         109-Mississippi River Valley
  >aquifer system                    alluvial aquifer
  >
  >Great Plains aquifer          304-Lower Cretaceous
  >                                  aquifers
  >
  >Confining unit                999-Other rocks
  >
  >Dune sand                     107-High Plains aquifer
  >
  >
  >GWA chapter HA 730-E
  >Name from fig 4, page E3      aq_code-aq_name
  >____________________________________________________________
  >EDWARDS-TRINITY AQUIFER SYSTEM
  >Edwards-Trinity aquifer       501-Edwards-Trinity aquifer
  >                                  system
  >
  >Edwards aquifer               501-Edwards-Trinity aquifer
  >                                  system
  >
  >Trinity aquifer               501-Edwards-Trinity aquifer
  >                                  system
  >
  >Confining unit                999-Other rocks
  >
  >
  >GWA chapter HA 730-F
  >Name from fig 7, page 4       aq_code-aq_name
  >____________________________________________________________
  >MAJOR AQUIFER SYSTEMS
  >Surficial aquifer system      109-Mississippi River Valley
  >                                  alluvial aquifer
  >                              203-Mississippi embayment
  >                                  aquifer system
  >                              501-Edwards-Trinity aquifer
  >                                  system
  >                              999-Other rocks
  >
  >Mississippi embayment         109-Mississippi River Valley
  >aquifer system                    alluvial aquifer
  >                              203-Mississippi embayment
  >                                  aquifer system
  >                              204-Southeastern Coastal
  >                                  Plain aquifer system
  >                              999-Other rocks
  >
  >Tokio-Woodbine aquifer        999-Other rocks
  >
  >Ouachita Mountains aquifer    999-Other rocks
  >
  >CONFINING SYSTEMS AND CONFINING UNITS
  >Western Interior Plains       999-Other rocks
  >confining systems
  >
  >Confining unit                109-Mississippi River Valley
  >                                  alluvial aquifer
  >                              203-Mississippi embayment
  >                                  aquifer system
  >                              999-Other rocks
  >
  >
  >GWA chapter HA 730-G
  >Name from fig 3, page 3       aq_code-aq_name
  >____________________________________________________________
  >Sand and gravel aquifer       201-Coastal lowlands aquifer
  >                                  system
  >
  >Piedmont and Blue Ridge       611-Piedmont and Blue Ridge
  >aquifers                          crystalline-rock aquifers
  >
  >Appalachian Plateaus          310-Pennsylvanian aquifers
  >aquifers
  >
  >Interior Low Plateaus         503-Mississippian aquifers
  >aquifers
  >
  >Confining unit                999-Other rocks
  >
  >
  >GWA chapter HA 730-H
  >Name from fig 5, page H4      aq_code-aq_name
  >____________________________________________________________
  >Unconsolidated-deposit        101-Basin and Range basin-fill
  > aquifers                         aquifers
  >                              104-Pacific Northwest
  >                                  basin-fill aquifers
  >                              105-Northern Rocky Mountains
  >                                  Intermontane Basins
  >                                  aquifer system
  >                              112-Puget Sound aquifer system
  >
  >
  >Pliocene and younger          606-Snake River Plain
  >basaltic-rock aquifers            basaltic-rock aquifers
  >                              610-Pacific Northwest
  >                                  basaltic-rock aquifers
  >
  >Miocene basaltic-rock         606-Snake River Plain
  >aquifers                          basaltic-rock aquifers
  >                              607-Columbia Plateau basaltic-rock
  >                                  aquifers
  >                              610-Pacific Northwest
  >                                  basaltic-rock aquifers
  >
  >Aquifers in pre-Miocene       401-Basin and Range
  >rocks                             carbonate-rock aquifers
  >                              999-Other rocks
  >
  >
  >GWA chapter HA 730-I.  See Process Description regarding
  >differences between this data and the printed Ground Water
  >Atlas chapter in Western Montana
  >Name from fig 7, page I4      aq_code-aq_name
  >____________________________________________________________
  >Quaternary volcanic and       610-Pacific Northwest
  >sedimentary rock aquifers         basaltic-rock aquifers
  >
  >Upper Tertiary aquifers       105-Northern Rocky Mountains
  >                                  Intermontane Basins
  >                                  aquifer system
  >                              107-High Plains aquifer
  >                              314-Lower Tertiary aquifers
  >                              316-Wyoming Tertiary aquifers
  >
  >Lower Tertiary aquifers       107-High Plains aquifer
  >                              314-Lower Tertiary aquifers
  >
  >Upper Cretaceous aquifers     301-Colorado Plateaus
  >                                  aquifers
  >                              315-Upper Cretaceous
  >                                  aquifers
  >
  >Lower Cretaceous aquifers     301-Colorado Plateaus
  >                                  aquifers
  >                              304-Lower Cretaceous aquifers
  >
  >Confining unit                301-Colorado Plateaus
  >                                  aquifers
  >
  >
  >GWA chapter HA 730-J
  >Name from fig 7, page J4      aq_code-aq_name
  >____________________________________________________________
  >Cretaceous aquifer            304-Lower Cretaceous
  >                                  aquifers
  >
  >MISSISSIPPIAN AQUIFER
  >Carbonate rocks               503-Mississippian aquifers
  >
  >Sandstone                     311-Marshall aquifer
  >
  >Crystalline-rock aquifer      999-Other rocks
  >
  >Confining unit                312-Cambrian-Ordovician
  >                                  aquifer system
  >                              999-Other rocks
  >
  >
  >GWA chapter HA 730-K
  >Name from fig 5, page K4      aq_code-aq_name
  >____________________________________________________________
  >Blue Ridge aquifers           611-Piedmont and Blue Ridge
  >                                  crystalline-rock aquifers
  >
  >MISSISSIPPI EMBAYMENT AQUIFER SYSTEM
  >Upper Claiborne, middle       109-Mississippi River Valley
  >Claiborne, middle Wilcox,         alluvial aquifer
  >and lower Wilcox              203-Mississippi embayment
  >                                  aquifer system
  >
  >McNairy-Nacatoch              204-Southeastern Coastal
  >                                  Plain aquifer system
  >
  >Pennsylvanian aquifers        999-Other rocks
  >
  >Confining unit                999-Other rocks
  >
  >
  >GWA chapter HA 730-L
  >Name from fig 7, page L4      aq_code-aq_name
  >____________________________________________________________
  >NORTHERN ATLANTIC COASTAL PLAIN AQUIFER SYSTEM
  >Surficial aquifer             111-Surficial aquifer system
  >                              205-Northern Atlantic
  >                                  Coastal Plain aquifer
  >                                  system
  >
  >Chesapeake aquifer            205-Northern Atlantic
  >                                  Coastal Plain aquifer
  >                                  system
  >
  >Castle Hayne-Aquia aquifer    418-Castle Hayne aquifer
  >
  >Severn-Magothy aquifer        205-Northern Atlantic
  >                                  Coastal Plain aquifer
  >                                  system
  >
  >Peedee-upper Cape Fear        205-Northern Atlantic
  >aquifer                           Coastal Plain aquifer
  >                                  system
  >
  >Potomac aquifer               205-Northern Atlantic
  >                                  Coastal Plain aquifer
  >                                  system
  >
  >PIEDMONT AND BLUE RIDGE AQUIFERS
  >Aquifers in early Mesozoic    308-Early Mesozoic basin
  >basins                            aquifers
  >
  >Carbonate-rock aquifers       417-Piedmont and Blue Ridge
  >                                  carbonate-rock aquifers
  >
  >Crystalline-rock aquifers     611-Piedmont and Blue Ridge
  >                                  crystalline-rock aquifers
  >
  >Valley and Ridge              416-New York and New England
  >carbonate-rock aquifers           carbonate-rock aquifers
  >                              505-Valley and Ridge
  >                                  carbonate-rock aquifers
  >
  >APPALACHIAN PLATEAUS
  >Permian and Pennsylvanian     310-Pennsylvanian aquifers
  >aquifers
  >
  >Not a principal aquifer       611-Piedmont and Blue Ridge
  >                                  crystalline-rock aquifers
  >
  >
  >GWA chapter HA 730-M
  >Name from fig 10, page M5     aq_code-aq_name
  >____________________________________________________________
  >SANDSTONE AQUIFERS
  >Mesozoic sandstone and        308-Early Mesozoic basin
  >basalt of the Newark              aquifers
  >Supergroup
  >
  >Lower Paleozoic               309-New York sandstone
  >                                  aquifers
  >
  >CRYSTALLINE-ROCK AQUIFERS
  >Adirondack                    999-Other rocks
  >
  >
  >GWA chapter HA 730-N
  >Hawaii name from fig 35,
  >page N14
  >Puerto Rico name from
  >fig 71, page N24              aq_code-aq_name
  >____________________________________________________________
  >Volcanic rock aquifers        608-Hawaiian Volcanic-rock
  >                                  aquifers
  >                              609-Hawaiian Sedimentary
  >                                  deposit aquifers
  >
  >MINOR AQUIFERS
  >Coastal embayment aquifers    999-Other rocks
  >Volcaniclastic-, igneous-,
  >and sedimentary-rock aquifers
  >
  >Confining unit                999-Other rocks
  >
  >NORTHCOAST LIMESTONE AQUIFER SYSTEM
  >Upper aquifer                 419-Puerto Rico North Coast Limestone
  >                                  aquifer system
  >
  >Lower aquifer                 419-Puerto Rico North Coast Limestone
  >                                  aquifer system
  >
  Related Spatial and Tabular Data Sets
  
  A map layer showing the areal extent of sand and gravel aquifers of
  alluvial and glacial origin north of the line of Quaternary continental
  glaciation is included in the online, interactive National Atlas of the
  United States.  This map layer ends at the southern limit of
  glaciation in the United States; areas north of the limit line contain
  significant sand and gravel glacial deposits that are important sources of
  water for local areas.
  
  For additional information on principal aquifers, please see the Aquifer
  Basics page at <http://capp.water.usgs.gov/aquiferBasics/index.html>.
  
  The final data are being served to the public in the following formats:
  Spatial Data Transfer Standard (SDTS), Arc/INFO Export, or ArcView
  Shapefile.
End_Group
Group: Related_URL
  URL_Type: 
  URL: <http://nationalatlas.gov/atlasftp.html>
  Group: Description
    Originator: U.S. Geological Survey
    Publication_Date: 200209
    Title: Aquifers of Alluvial and Glacial Origin
    Publication_Information:
      Publication_Place: Reston, VA
      Publisher: National Atlas of the United States
    Online_Linkage: <http://nationalatlas.gov/atlasftp.html>

  End_Group
End_Group
Group: Related_URL
  URL_Type: 
  URL: <http://nationalatlas.gov/atlasftp.html>
  Group: Description
    Originator: National Atlas of the United States
    Publication_Date: 1998
    Title: State Boundaries of the United States
    Geospatial_Data_Presentation_Form: Map
    Publication_Information:
      Publication_Place: Reston,VA
      Publisher: U.S. Geological Survey
    Online_Linkage: <http://nationalatlas.gov/atlasftp.html>
  End_Group
End_Group
Group: DIF_Author
  Last_name: Chief
  First_name: Cartographic
  Middle_name: and Publications Program, Water
  Phone: 608-238-9333
  Group: Address
    505 Science Drive
    Madison, WI 53711
    USA
  End_Group
End_Group
DIF_Revision_Date: 20050426
Science_Review_Date: