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<metadata xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://water.usgs.gov/GIS/metadata/usgswrd/fgdc-std-001-1998.xsd">
  <idinfo>
    <citation>
      <citeinfo>
        <origin>Cederstrand, Joel R.</origin>
        <origin>Becker, Mark F.</origin>
        <pubdate>1998</pubdate>
        <title>Digital Map Of Base of Aquifer for High Plains Aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming</title>
        <edition>1.0</edition>
        <geoform>map</geoform>
        <serinfo>
          <sername>Open-File Report</sername>
          <issue>OFR98-393</issue>
        </serinfo>
        <pubinfo>
          <pubplace>Reston, VA</pubplace>
          <publish>U.S. Geological Survey</publish>
        </pubinfo>
        <onlink>https://water.usgs.gov/lookup/getspatial?ofr98-393_aqbase</onlink>
      </citeinfo>
    </citation>
    <descript>
      <abstract>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.</abstract>
      <purpose>This data set was created to archive the original map produced
by the High Plains RASA project and make available the data on
those maps for use with geographic information systems.</purpose>
      <supplinf>Introduction --
		
The information provided in the introduction is found in
U.S. Geological Survey Professional Paper 1400-B (Gutentag and
others, 1984). This data set consists of digital base of aquifer
contours for the High Plains aquifer in the United States.  The
High Plains aquifer, which underlies about 174,000 square miles
in parts of eight states, is the principal water source in one
of the nation's major agricultural areas. In 1980, about 170,000
wells pumped water from the aquifer to irrigate about 13 million
acres.
		
The High Plains aquifer is a regional water-table aquifer
consisting mostly of near-surface sand and gravel deposits.  In
1980, the maximum saturated thickness of the aquifer was about
1,000 feet and averaged 200 feet.  Hydraulic conductivity and
specific yield were highly variable because of the heterogeneity
of the aquifer.  Hydraulic conductivity and specific yield of
the aquifer depend on sediment types, which vary significantly
both horizontally and vertically.  Hydraulic conductivity ranged
from less than 25 to greater than 300 feet per day and averaged
60 feet per day.  Specific yields ranged from less than 10 to 30
percent and averaged about 15 percent.
		
The High Plains aquifer boundaries were determined by erosional
extent of the High Plains aquifer and hydrologic boundaries
where the High Plains aquifer extends eastward from the Great
Plains physiographic province (Fenneman, 1931).  In most of the area, the erosional extent of
hydraulically-connected Tertiary and Quaternary rocks were used.
In eastern Nebraska, the boundaries used were streams as
hydrologic boundaries of Quaternary deposits and physiographic
provinces.  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 High Plains RASA project (Gutentag and others,
1984).
		
Reviews Applied to Data --
		
This electronic report was subjected to the same review standard
that applies to all U.S. Geological Survey reports. Reviewers
were asked to check the topological consistency, tolerances,
attribute frequencies and statistics, projection, and geographic
extent.  Reviewers were given digital data sets for checking
against the source maps to verify the linework and
attributes.  The reviewers checked the metadata files for
completeness and accuracy.
		
Related Spatial and Tabular Data Sets --
		
Other References Cited --
		
Fenneman, N.M., 1931, Physiography of western United States (1st
ed.): New York, McGraw-Hill, 534 p.
		
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.
		
Notes --
		
Any use of trade, product, or firm names is for descriptive
purposes only and does not imply endorsement by the U.S.
Government.
		
Although this data set has been used by the U.S. Geological
Survey, U.S. Department of the Interior, no warranty expressed or
implied is made by the U.S. Geological Survey as to the accuracy
of the data and related materials.
		
The act of distribution shall not constitute any such warranty,
and no responsibility is assumed by the U.S. Geological Survey
in the use of this data, software, or related materials.</supplinf>
    </descript>
    <timeperd>
      <timeinfo>
        <sngdate>
          <caldate>1998</caldate>
        </sngdate>
      </timeinfo>
      <current>1980</current>
    </timeperd>
    <status>
      <progress>Complete</progress>
      <update>None planned</update>
    </status>
    <spdom>
      <bounding>
        <westbc>-104.542</westbc>
        <eastbc>-96.305</eastbc>
        <northbc>43.806</northbc>
        <southbc>31.652</southbc>
      </bounding>
    </spdom>
    <keywords>
      <theme>
        <themekt>USGS Thesaurus</themekt>
        <themekey>aquifers</themekey>
        <themekey>ground water</themekey>
        <themekey>groundwater</themekey>
        <themekey>High Plains aquifer</themekey>
        <themekey>Ogallala Formation</themekey>
        <themekey>Ogallala aquifer</themekey>
        <themekey>aquifer boundary</themekey>
        <themekey>inlandWaters</themekey>
      </theme>
      <theme>
        <themekt>ISO 19115 Topic Category</themekt>
        <themekey>geoscientificInformation</themekey>
        <themekey>inlandWaters</themekey>
        <themekey>environment</themekey>
      </theme>
      <theme>
        <themekt>USGS Metadata Identifier</themekt>
        <themekey>USGS:cccb0a25-4594-459d-8c47-b294b11bf9ed</themekey>
      </theme>
       <place>
        <placekt>Geographic Names Information System</placekt>
        <placekey>High Plains</placekey>
        <placekey>Great Plains region</placekey>
        <placekey>western U.S.</placekey>
      </place>
    </keywords>
    <accconst>None.</accconst>
    <useconst>None</useconst>
    <ptcontac>
      <cntinfo>
        <cntperp>
          <cntper>Mark F. Becker</cntper>
          <cntorg>U.S. Geological Survey</cntorg>
        </cntperp>
        <cntpos>Hydrologist</cntpos>
        <cntaddr>
          <addrtype>mailing address</addrtype>
          <address>202 NW 66th St., Bldg. 7</address>
          <city>Oklahoma City</city>
          <state>Oklahoma</state>
          <postal>73116</postal>
          <country>United States of America</country>
        </cntaddr>
        <cntvoice>1-888-275-8747</cntvoice>
        <cntfax>(405) 843-7712</cntfax>
        <cntemail>mfbecker@usgs.gov</cntemail>
        <cntinst>none</cntinst>
      </cntinfo>
    </ptcontac>
    <browse>
      <browsen>https://water.usgs.gov/GIS/browse/ofr98-393.gif</browsen>
      <browsed>A browse image of the base of aquifer contours data set for the
High Plains aquifer.</browsed>
      <browset>GIF</browset>
    </browse>
    <datacred>None</datacred>
    <secinfo>
      <secsys>Public</secsys>
      <secclass>UNCLASSIFIED</secclass>
      <sechandl>None</sechandl>
    </secinfo>
    <native>Operating System-- UNIX, ARC/INFO Version 7.0.3,
(Mon Mar 13 22:21:55 PST 1995)</native>
  </idinfo>
  <dataqual>
    <logic>Chain-node topology present.</logic>
    <complete>This data set includes the base of aquifer elevation contours
published by Gutentag and others (1984) in U.S. Geological Survey
Professional Paper 1400-B.</complete>
    <posacc>
      <horizpa>
        <horizpar>None</horizpar>
        <qhorizpa>
          <horizpav>254 meters</horizpav>
          <horizpae>Resolution as
reported</horizpae>
        </qhorizpa>
      </horizpa>
      <vertacc>
        <vertaccr>None.</vertaccr>
      </vertacc>
    </posacc>
    <lineage>
      <procstep>
        <procdesc>A mylar map of the hydraulic conductivity contours was
digitized using ARC/INFO.</procdesc>
        <procdate>199702101045 -- 199702181343</procdate>
      </procstep>
      <procstep>
        <procdesc>The coverage was projected from Lambert Conformal Conic
projection with the 1927 North American Datum to an Albers
Equal-Area projection with the 1983 North American Datum using
ARC/INFO.  The new projection has standard parallels of 29
degrees 30 minutes and 45 degrees 30 minutes north latitude, a
central meridian of 96 degrees west longitude, and a latitude
of projection origin of 23 degrees north latitude.</procdesc>
        <procdate>199702181437 -- 199702181614</procdate>
      </procstep>
      <procstep>
        <procdesc>The coverage including features and attributes was checked
and corrected where necessary using ARC/INFO.  The MAJOR1,
MINOR1, and ELEV arc attributes were added and calculated.</procdesc>
        <procdate>199803161425 -- 199803171421</procdate>
      </procstep>
    </lineage>
  </dataqual>
  <spdoinfo>
    <direct>Vector</direct>
    <ptvctinf>
      <sdtsterm>
        <sdtstype>String</sdtstype>
        <ptvctcnt>358</ptvctcnt>
      </sdtsterm>
    </ptvctinf>
  </spdoinfo>
  <spref>
    <horizsys>
      <planar>
        <mapproj>
          <mapprojn>Albers Conical Equal Area</mapprojn>
          <albers>
            <stdparll>29.5</stdparll>
            <stdparll>45.5</stdparll>
            <longcm>-96</longcm>
            <latprjo>23</latprjo>
            <feast>0.0</feast>
            <fnorth>0.0</fnorth>
          </albers>
        </mapproj>
        <planci>
          <plance>coordinate pair</plance>
          <coordrep>
            <absres>200 meters</absres>
            <ordres>200 meters</ordres>
          </coordrep>
          <plandu>METERS</plandu>
        </planci>
      </planar>
      <geodetic>
        <horizdn>North American Datum of 1983</horizdn>
        <ellips>Geodetic Reference System 80</ellips>
        <semiaxis>6378137</semiaxis>
        <denflat>298.257</denflat>
      </geodetic>
    </horizsys>
  </spref>
  <eainfo>
    <detailed>
      <enttyp>
        <enttypl>AQBASE.AAT</enttypl>
        <enttypd>Arc attribute table</enttypd>
        <enttypds>ARC/INFO</enttypds>
      </enttyp>
      <attr>
        <attrlabl>-</attrlabl>
        <attrdef>Arc attribute table</attrdef>
        <attrdefs>ARC/INFO</attrdefs>
        <attrdomv>
          <edom>
            <edomv>-</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>FNODE#</attrlabl>
        <attrdef>Internal number of from-node</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Sequential unique positive integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>TNODE#</attrlabl>
        <attrdef>Internal number of to-node</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Sequential unique positive integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>LPOLY#</attrlabl>
        <attrdef>Internal number of poly to left of arc</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Sequential unique positive integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>RPOLY#</attrlabl>
        <attrdef>Internal number of poly to right of arc</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Sequential unique positive integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>LENGTH</attrlabl>
        <attrdef>Length of arc in coverage units</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Positive real numbers</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>AQBASE#</attrlabl>
        <attrdef>Internal feature number</attrdef>
        <attrdefs>Computed</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Sequential unique positive integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>AQBASE-ID</attrlabl>
        <attrdef>User-assigned feature number</attrdef>
        <attrdefs>User-defined</attrdefs>
        <attrdomv>
          <edom>
            <edomv>Integer</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>ELEV</attrlabl>
        <attrdef>Base of aquifer elevation in feet</attrdef>
        <attrdefs>Gutentag and others, 1984</attrdefs>
        <attrdomv>
          <edom>
            <edomv>1200, 1400, 1600, 1800, 2000,
2200, 2400, 2600, 2800, 3000,
3200, 3400, 3600, 3800, 4000,
4200, 4400, 4600, 4800, 5000,
5200, 5400, 5600, 5800, 6000,
6200, 6400, 6600, 6800, 7000</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>MAJOR1</attrlabl>
        <attrdef>Base of aquifer elevation in feet</attrdef>
        <attrdefs>Gutentag and others, 1984</attrdefs>
        <attrdomv>
          <edom>
            <edomv>1200, 1400, 1600, 1800, 2000,
2200, 2400, 2600, 2800, 3000,
3200, 3400, 3600, 3800, 4000,
4200, 4400, 4600, 4800, 5000,
5200, 5400, 5600, 5800, 6000,
6200, 6400, 6600, 6800, 7000</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
      <attr>
        <attrlabl>MINOR1</attrlabl>
        <attrdef>0</attrdef>
        <attrdefs>n/a</attrdefs>
        <attrdomv>
          <edom>
            <edomv>0</edomv>
            <edomvd>n/a</edomvd>
            <edomvds>n/a</edomvds>
          </edom>
        </attrdomv>
      </attr>
    </detailed>
    <overview>
      <eaover>Each line in this data set has associated attributes of ELEV and
MAJOR1 containing values of base of aquifer elevations expressed
in feet.</eaover>
      <eadetcit>See overview.</eadetcit>
    </overview>
  </eainfo>
  <distinfo>
    <distrib>
      <cntinfo>
        <cntorgp>
          <cntorg>U.S. Geological Survey</cntorg>
          <cntper>Michael Ierardi</cntper>
        </cntorgp>
        <cntpos>IT Specialist</cntpos>
        <cntaddr>
          <addrtype>mailing</addrtype>
          <address>445 National Center</address>
          <city>Reston</city>
          <state>VA</state>
          <postal>20192</postal>
        </cntaddr>
        <cntvoice>1-888-275-8747 (1-888-ASK-USGS)</cntvoice>
        <cntemail>mierardi@usgs.gov</cntemail>
      </cntinfo>
    </distrib>
    <distliab>Although this data set has been used by the U.S. Geological
Survey, U.S. Department of the Interior, no warranty expressed or
implied is made by the U.S. Geological Survey as to the accuracy
of the data and related materials. The act of distribution shall not 
constitute any such warranty, and no responsibility is assumed by 
the U.S. Geological Survey in the use of this data, software, or 
related materials.
		
Any use of trade, product, or firm names is for descriptive
purposes only and does not imply endorsement by the U.S.
Government.</distliab>
    <stdorder>
      <digform>
        <digtinfo>
          <formname>Export</formname>
          <formcont>Full coverage</formcont>
          <filedec>zipped</filedec>
          <transize>1</transize>
        </digtinfo>
        <digtopt>
          <onlinopt>
            <computer>
              <networka>
                <networkr>https://water.usgs.gov/GIS/dsdl/ofr98-393.e00.gz</networkr>
              </networka>
            </computer>
          </onlinopt>
        </digtopt>
      </digform>
      <digform>
        <digtinfo>
          <formname>Other</formname>
          <formcont>DLG file format</formcont>
          <filedec>zipped</filedec>
          <transize>1</transize>
        </digtinfo>
        <digtopt>
          <onlinopt>
            <computer>
              <networka>
                <networkr>https://water.usgs.gov/GIS/dsdl/ofr98-393.dlg.gz</networkr>
              </networka>
            </computer>
          </onlinopt>
        </digtopt>
      </digform>
      <fees>None. This dataset is provided by USGS as a public service.</fees>
    </stdorder>
  </distinfo>
  <metainfo>
    <metd>20201117</metd>
    <metc>
      <cntinfo>
        <cntorgp>
          <cntorg>U.S. Geological Survey</cntorg>
        </cntorgp>
        <cntpos>Ask USGS -- Water Webserver Team</cntpos>
        <cntaddr>
          <addrtype>mailing</addrtype>
          <address>445 National Center</address>
          <city>Reston</city>
          <state>VA</state>
          <postal>20192</postal>
        </cntaddr>
        <cntvoice>1-888-275-8747 (1-888-ASK-USGS)</cntvoice>
        <cntemail>mierardi@usgs.gov</cntemail>
      </cntinfo>
    </metc>
    <metstdn>FGDC Content Standards for Digital Geospatial Metadata</metstdn>
    <metstdv>FGDC-STD-001-1998</metstdv>
  </metainfo>
</metadata>
