Principal Aquifers of the 48 Conterminous United States
Entry ID:
USGS_aquifers_us
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Summary
Abstract:
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 data set contains the shallowest principal aquifers of the conterminous United States, portrayed as polygons. The data set 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 data set was previously called Principal Aquifers of the 48
Contiguous United States.
The Ground Water Atlas of the United States (GWA) chapters include additional
information that may be relevant to the use of this data set, such as maps of
alluvial and glacial aquifers that overlie the aquifers in this data set, as
well as other information described below.
The aerial extent of the aquifers, as shown in this data set, 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can be withdrawn, for two reasons: 1) The aquifers shown may have a larger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 data set
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 data set. Major
alluvial aquifers that occur along main watercourses are not shown. Significant
unconsolidated sand and gravel aquifers, that are not indicated in this data
set but are important sources of water, may occur locally in glaciated regions.
The user of this data set 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 data set 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 data set. 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, Roy Sonenshein, sunshine@usgs.gov, (305) 717-5824.
This data set 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 data set 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
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.
Although these spatial data can stand alone, it may be helpful to refer to the
printed GWA chapters when using the data. There are three subject areas in
which there are significant differences between this data set and the printed
chapters: category changes, which are described below; coastline location, and
the representation of aquifers in Western Montana, both of which are discussed
in the Process Description under Lineage.
Category Changes
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. In most cases, the name
and delineation of the aquifer is identical between this data set and the GWA
printed maps, but there are several areas of differences. In some cases, a
single aquifer from a GWA chapter is represented among multiple aquifers in
this data set.
The following listings show the differences between aquifer names in the GWA
chapters and the aq_name and aq_code used in this data set. 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 system
Confining unit 999-Not a principal aquifer
Not a principal aquifer 999-Not a principal aquifer
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-Not a principal aquifer
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-Not a principal aquifer
Mississippi embayment 109-Mississippi River Valley
aquifer system alluvial aquifer
203-Mississippi embayment
aquifer
204-Southeastern Coastal
Plain aquifer system
999-Not a principal aquifer
MINOR AQUIFERS AND AQUIFER SYSTEMS - Aquifer systems in
rocks of cretaceous age
Edwards-Trinity aquifer 501-Edwards-Trinity aquifer
system (Trinity aquifer) system
Tokio-Woodbine aquifer 999-Not a principal aquifer
Ouachita Mountains aquifer 999-Not a principal aquifer
CONFINING SYSTEMS AND CONFINING UNITS
Western Interior Plains 999-Not a principal aquifer
confining systems
Confining unit 109-Mississippi River Valley
alluvial aquifer
203-Mississippi embayment
aquifer system
999-Not a principal aquifer
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 999-Not a principal aquifer
aquifers
Appalachian Plateaus 310-Pennsylvanian aquifers
aquifers
Interior Low Plateaus 503-Mississippian aquifers
aquifers
Confining unit 999-Not a principal aquifer
GWA chapter HA 730-H
Name from fig 5, page H4 aq_code-aq_name
____________________________________________________________
Unconsolidated-deposit 104-Pacific Northwest
aquifers basin-fill aquifers
112-Puget-Willamette Lowland
aquifer system
105-Northern Rocky Mountains
Intermontane basins
aquifer system
101-Basin and Range aquifers
Pliocene and younger 603-Pliocene and younger
basaltic-rock aquifers basaltic-rock aquifers
606-Snake River Plain
aquifer system
Miocene basaltic-rock 607-Columbia Plateau aquifer
aquifers system
604-Miocene basaltic-rock
aquifers
Aquifers in pre-Miocene 401-Basin and Range
rocks carbonate-rock aquifers
999-Not a principal aquifer
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 605-Volcanic and
sedimentary rock aquifers sedimentary-rock
aquifers
Upper Tertiary aquifers 107-High Plains aquifer
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 aquifer
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-Mississippian aquifers
of Michigan
Crystalline-rock aquifer 999-Not a principal aquifer
Confining unit 999-Not a principal aquifer
GWA chapter HA 730-K
Name from fig 5, page K4 aq_code-aq_name
____________________________________________________________
Blue Ridge aquifers 308-Early Mesozoic basin
aquifers
999-Not a principal aquifer
MISSISSIPPI EMBAYMENT AQUIFER SYSTEM
Upper Claiborne, middle 203-Mississippi embayment
Claiborne, middle Wilcox, aquifer system
and lower Wilcox 109-Mississippi River Valley
alluvial aquifer
McNairy-Nacatoch 204-Southeastern Coastal
Plain aquifer system
Confining unit 999-Not a principal aquifer
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
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 999-Not a principal aquifer
Valley and Ridge 505-Valley and Ridge
carbonate-rock aquifers carbonate-rock aquifers
416-New York and New England
carbonate-rock aquifers
APPALACHIAN PLATEAUS
Permian and Pennsylvanian 310-Pennsylvanian aquifers
aquifers
GWA chapter HA 730-M
Name from fig 10, page M5 aq_code-aq_name
____________________________________________________________
CARBONATE-ROCK AQUIFERS
New York and New England 416-New York and New England
carbonate-rock aquifers
Valley and Ridge 416-New York and New England
carbonate-rock aquifers
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-Not a principal aquifer
New England 999-Not a principal aquifer
Related Spatial and Tabular Data Sets
A data set showing the extent of glacial deposits is included in the online,
interactive National Atlas of the United States, but is not available to
download. This data set shows the southern limit of glaciation in the United
States; areas north of the limit line may contain significant sand and gravel
glacial deposits that are important sources of water for local areas.
A data set of aquifers of Alaska is in work.
A data set of aquifers of Puerto Rico and the U.S. Virgin Islands is in work.
A data set of aquifers of Hawaii is planned.
The final data are being served to the public in the following formats:
Spatial Data Transfer Standard (SDTS), Arc/INFO Export, or ArcView Shapefile. 
Multimedia Sample
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Caption:
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Geographic Coverage
(Click for Interactive Map)
Spatial coordinates
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N: 49.39
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S: 24.52
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E: -66.94
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W: -124.76
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Data Set Citation
Dataset Originator/Creator:
James A. Miller
Dataset Title:
Principal Aquifers of the 48 Conterminous United States
Dataset Release Date:
1998-07-01
Dataset Release Place:
Madison, Wisconsin, USA
Dataset Publisher:
U.S. Geological Survey
Version:
Version 1.0
Data Presentation Form:
Map
Online Resource:
http://water.usgs.gov/lookup/getspatial?aquifers_us
Temporal Coverage
Start Date:
1998-07-01
Stop Date:
1998-07-01
Data Resolution
Latitude Resolution:
1km
Longitude Resolution:
1km
Distribution
Distribution Media:
DVD-R
Distribution Media:
Online Download
Creation and Review Dates
DIF Creation Date:
2012-08-21
Last DIF Revision Date:
2012-09-10
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