Fischer, Brian C. McGuire, Virginia L. 1999 1.0 map Open-File Report USGS OFR 99-96 Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ofr00-96_wlc80_97 Fischer, Brian C.; Kollasch, Keith M.; McGuire, Virginia L. 2000 http://pubs.er.usgs.gov/publication/ofr200096 This data set consists of digital water-level-change contours for the High Plains aquifer in the central United States, 1980 to 1997. The High Plains aquifer extends from south of 32 degrees to almost 44 degrees north latitude and from 96 degrees 30 minutes to 104 degrees west longitude. The aquifer underlies about 174,000 square miles in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. This digital data set was created from 5,233 wells measured in both 1980 and 1997. The water-level-change contours were drawn manually on mylar at a scale of 1:1,000,000. The contours then were converted to a digital map. This data set was created to document the original map (McGuire, V.L. and Fischer, B.C., 1999) produced by the High Plains Water-Level Monitoring project and to make available the data on this map for use with geographic information systems. Introduction -- The information provided in this introduction is found in U.S. Geological Survey Professional Paper 1400-B (Gutentag and others, 1984). This data set consists of digital water-level-change contours for the High Plains aquifer in the United States, 1980 to 1997. 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 about 200 feet. 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 associated geologic units and by hydraulic and physiographic 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 the hydraulically connected Tertiary and Quaternary deposits were used as the aquifer boundary. In eastern Nebraska, streams and physiographic boundaries were used as the aquifer boundary. Reviews Applied to Data -- This electronic report was subjected to the same review standards that apply 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 -- Predevelopment to 1980 water-level change digital data set 1980 to 1994 water-level change digital data set 1980 to 1995 water-level change digital data set 1980 to 1996 water-level change digital data set 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. McGuire, V.L., and Fischer, B.C., 1999, Water-level changes ,1980 to 1997, and saturated thickness, 1996-97, in the High Plains aquifer: U.S. Geological Survey Fact Sheet FS-124-99. 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. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file may include some ARC/INFO-specific terminology. 1999 1997 Complete None Planned -106.015 -96.260 43.806 31.652 none aquifers ground water groundwater High Plains aquifer Ogallala Formation Ogallala aquifer water-level change inlandWaters none High Plains Great Plains region western U.S. none These data are not to be used at scales greater than 1:1,000,000 Virginia L. McGuire U.S. Geological Survey Hydrologist mailing address

Room 406 Federal Bldg., 100 Centennial Mall North

Lincoln NE 68508 USA 1-888-275-8747 (402) 437-5139 Webmaster@ne20dnelnc.cr.usgs.gov http://water.usgs.gov/GIS/browse/ofr00-96_wlc80_97.gif A browse image of the water-level-change contours data set for the High Plains aquifer, 1980 to 1997. GIF McGuire, Virginia L. and Fischer, Brian C. Public UNCLASSIFIED None dgux, R4.11MU04, AViiON UNIX ARC/INFO version 7.1.1 Polygon and chain-node topology present. This data set includes the water-level-change contours produced by McGuire and Fischer (1999) in U.S. Geological Survey Fact Sheet FS-124-99. No tests preformed, except a visual check to see how well the data set polygons corresponded to those on the original mylar. Water-level points for 5,233 wells were reviewed and then printed on mylar with the aquifer boundary and areas where the aquifer has little or no saturated thickness (modified from Gutentag and others, 1984). Contours were then handdrawn using an interpolated grid from ARC/INFO and the 1980 to 1996 water-level contours as a background and reference to handdraw the contours. The interpolation method used in ARC/INFO was Kriging with the universal1 method. 199810 Digitized the water-level change contours from the mylar. ARC/INFO software and commands then were used to create the coverage. ARC/INFO commands are shown below in capitals. Step 1. Copied the aquifer boundary with the internal areas where the aquifer is not present using the COPY command. This coverage was projected to Albers Equal-Area projection with the 1927 North American Datum using ARC/INFO. The projection has standard parallel 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. Step 2. Used the coverage from step one to register to the digitizer. The RMS error was 0.003 meters. Step 3. Digitized the water-level change contours from the mylar. ARCSNAP was turned on to snap water-level contours to the aquifer boundary. Step 4. Built polygon topology using BUILD command. Step 5. Assigned attribute data to polygons using ARCEDIT and the digitizer. 199811 Step 6. The polygons were reviewed, using an aml to compare the water-level change value with the polygon range, and manually edited where needed using ARCEDIT. 199812 Step 7. Used UNSPLIT in Arcedit to remove unnecessary psuedo nodes. Step 8. Rebuilt topology. Step 9. Copied coverage from DOUBLE to SINGLE precision and CLEANed. Step 10. Used RENODE to number nodes sequentially. Step 11. Used UNSPLIT to remove 94 pseudo nodes from the arcs, reducing the number of arcs from 1152 to 1058. 199906 Vector GT-polygon composed of chains 874 Albers Conical Equal Area 29.5 45.5 -96 23 0.0 0.0 coordinate pair 0.001 0.001 Meters North American Datum of 1927 Clarke 1866 6378206.4 294.98 Each polygon in this data set has an associated attribute of RANGE containing ranges of water-level change expressed in feet or an identification of ISLAND, noting an area where the aquifer is not present. There is a polygon attribute table associated with this file: WLC80_97.PAT: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 AREA 4 12 F 3 5 PERIMETER 4 12 F 3 9 WLC80_97# 4 5 B - 13 WLC80_97-ID 4 5 B - 17 RANGE 10 10 C - AREA is the area of the polygon in square meters PERIMETER is the perimeter of the polygon in meters WLC80_97# is a program-generated feature identity number WLC80_97-ID is a user-assigned feature number RANGE is the polygon's water-level change range in feet or a polygon's identification of an internal area where the aquifer is not present. The unique combinations of the attribute item RANGE are listed below: Less than -40 -40 to -20 -20 to -10 -10 to -5 -5 to 5 5 to 10 10 to 20 20 to 40 Greater than 40 island none U.S. Geological Survey Ask USGS - Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ofr00-96_wlc80_97 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. Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/wlc80_97.e00.gz Shape Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/wlc80_97.shp.gz SDTS Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/ofr00-96_wlc80_97_SDTS.tgz None. This dataset is provided by USGS as a public service. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ofr00-96_wlc80_97 FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998