Fischer, Brian C. Kollasch, Keith M., University of Nebraska-Lincoln, employed under contract number 7CRSA00438 McGuire, Virginia L. 2000 1.0 map Open-File Report USGS OFR 00-300 Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ofr00-300_sattk9697 Brian C. Fischer, Keith M. Kollasch and Virginia L. McGuire 2000 http://pubs.usgs.gov/of/2000/ofr00-300/ This digital data set consists of saturated thickness contours for the High Plains aquifer in Central United States, 1996-97. 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 data set was based on 10,085 water-level measurements, 49 stream elevations, (March 1997) and 10,036 water-level elevations from wells (1,370 from 1996 and 8,666 from 1997) and the base of aquifer value for each measurement location. The saturated thickness at each measurement location was determined by subtracting the water-level elevation from the base of aquifer at that location. This data set was created to document the original map (McGuire and Fischer, 1999) produced by the High Plains Water-level Monitoring project and make available the data on this map for use with geographic information systems. This map is published in the web report "Water-level changes, 1980 to 1997, and saturated thickness, 1996-97, in the High Plains aquifer" and USGS Fact Sheet 124-99, "Water-level changes, 1980 to 1997, and saturated thickness, 1996-97, in the High Plains aquifer". 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 saturated thickness contours for the High Plains aquifer in Central United States, 1996-97 (modified from Weeks and Gutentag, 1981; Cederstrand and Becker, 1999). 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 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 -- Digital map of saturated thickness in 1980 for the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. References Cited -- Cederstrand, J.R., and Becker, M.F., 1999, Digital map of saturated thickness in 1980 for the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Open-File Report OFR-99 262, scale 1:1,000,000. 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. Weeks, J.B., and Gutentag, E.D., 1981, Bedrock geology, altitude of base, and 1980 saturated thickness of High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming: U.S. Geological Survey Hydrologic Investigations Atlas HA-648, 2 sheets, scale 1:2,500,000. McGuire, V.L., and Fischer, B.C., 1999, Water-level changes in the High Plains aquifer-1980 to 1997: 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 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 saturated thickness High Plains aquifer Ogallala Formation Ogallala aquifer 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

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Lincoln NE 68508 USA 1-888-275-8747 (402) 437-5139 GS-W-NE_@usgs.gov http://water.usgs.gov/GIS/browse/ofr00-300_sattk9697.gif A browse image of the saturated thickness contours data set for the High Plains aquifer 1996-97. GIF McGuire, Virginia L., and Fischer, Brian C. Public UNCLASSIFIED None dgux, R4.11MU04, AViiON UNIX ARC/INFO version 7.1.1 none Polygon and chain-node topology present. This data set includes the saturated thickness polygons produced by McGuire and Fischer,(1999) in the U.S. Geological Survey Factsheet FS-124-99. No tests performed, except a visual check to see how well the data set polygons corresponded to those on the original mylar, scale 1:1,000,000. Weeks, John B., and Gutentag, Edwin D. 1981 map Hydrologic Investigations Atlas USGS HA-648 Oklahoma City, OK U.S. Geological Survey mylar 1980 1980 (none) 1996-97 polygons were modified from 1980 saturated thickness contours Selected wells screened in the High Plains aquifer that were measured in preirrigation season 1996 or 1997 and had land surface elevation determined. Selected the 1997 water-level elevation, if available, or the 1996 water-level elevation if the 1997 water-level is not available. Calculated water-level elevation for each well in the coverage, WL_PTS_ALL. ARC/INFO software and commands then were used to create the coverage. ARC/INFO commands are shown below in capitals. Step 1. Appended the available March 1997 stream-level elevations for northeastern Colorado, northwestern Kansas, and Nebraska to the WL_PTS_ALL coverage. Step 2. Used TOPOGRID to make a grid of the aquifer base using the High Plains Regional Aquifer System Analysis map (Weeks and Gutentag, 1981; Cederstrand and Becker, 1999). The grid has a cell size of 500 meters. The base of aquifer map has 200-foot contours. The scale of the base of aquifer map is 1 to 1,000,000 (Cederstrand and Becker, 1999). Step 3. Clipped aquifer base grid to the aquifer boundary using LATTICECLIP command. 19981012 Step 4. Used LATTICESPOT to calculate aquifer base value for each well with water-level elevation in 1996-97 and stored in the coverage WL_PTS_ALL. Step 5. Added an item, using ADDITEM command, for saturated thickness for each well with water-level elevation in 1996-97, calculated saturated thickness for each well, and stored in cover WL_PTS_ALL. 19981015 Step 6. Used TOPOGRID to make a grid of the water table from well with water-level elevation in 1996-97 and March 1997 stream-elevations. Renamed the water-table, wt_grd. Step 7. Copied the aquifer base using the COPY command. Used TOPOGRID to create the grid aquifer base, aqbase_grd. 19981016 Step 8. Created the grid saturated thickness, SAT_WL_GRD, by calculating, SAT_WL_GRD = wt_grd - aqbase_grd. Step 9. Clipped the saturated thickness grid to the aquifer boundary. SAT_WL_GRD2 = SELECTPOLYGON(SAT_WL_GRD). Step 10. Sliced the saturated thickness grid by contour intervals. SLICE_SAT = SLICE (SAT_WL_GRD2, table, slice, value, value) Step 11. Changed the saturated thickness grid into an integer grid using, temp = INT (slice_sat), BUILDVAT temp, RENAME temp sat_thick_fin, RENAME sat_thick_fin sat_wl_grd commands. Step 12. Printed the saturated thickness grid (sat_wl_grd) and point values of saturated thickness (wl_pts_all) on mylar, manually modified the contours to agree with the point values or with previously published maps where current point values are not available. The final coverage of saturated thickness contours is called sat_thick_dig. 19981017 First draft of metadata created by bfischer using FGDCMETA.AML ver. 1.32 01/11/99 on ARC/INFO data set /account2/bfischer/hp_covers/sattk_97 19990618 Vector GT-polygon composed of chains 408 Albers Conical Equal Area 29.5 45.5 -96 23 0.00000 0.00000 coordinate pair 0.461 0.461 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 saturated thickness expressed in feet or an identification of "island" noting an area within the main aquifer boundary where the aquifer is not present. There is a polygon attribute table associated with this file: SATTK_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 SATTK_97# 4 5 B - 13 SATTK_97-ID 4 5 B - 17 RANGE 12 12 C - AREA is the area of the polygon in square meters PERIMETER is the perimeter of the polygon in meters SATTK_97# is a program-generated feature identity number SATTK_97-ID is a user-assigned feature number RANGE is the polygon's saturated thickness range in feet or a polygon's identification of an area where the aquifer is not present. The unique combinations of the attribute item RANGE are listed below: 0 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 800 800 to 1000 1000 to 1200 "island"-area within the main aquifer boundary where the aquifer is not present. 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+ofr00-300_sattk9697 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/sattk_97.e00.gz Shape Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/sattk_97.shape.tgz SDTS Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/sattk_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+ofr00-300_sattk9697 FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998