Flynn, Jennifer L., Arnold, L. Rick, and Paschke, Suzanne S. 2009 vector digital data USGS Data Series Data Series 472 Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ds472_equalareas Arnold, L.R., Flynn, J.L., and Paschke, S.S. 2009 USGS Data Series Data Series 456 These data are in support of report DS 456 (Arnold and others, 2009). 30 equal-area polygons generated using techniques described in Scott (1990). Polygons include areas overlying the High Plains Aquifer in Colorado having a depth to water less than 180 feet, a saturated thickness greater than 50 feet, and underlying irrigated agricultural lands. Described in Arnold and others (2009). Input saturated thickness and depth to water data from V.L. McGuire, written communication, 2008. Irrigated agricultural lands from Bauder and others (2004). Design a network to sample ground water for agricultural chemicals in areas of agricultural irrigation in the High Plains Aquifer in Colorado. Work done in cooperation with the Colorado Department of Agriculture. Arnold, L.R., Flynn, J.L., and Paschke, S.S., 2009, Design and installation of a groundwater monitoring-well network in the High Plains Aquifer, Colorado. U.S. Geological Survey Data Series 456. Bauder, T., Cipra, J., Waskom, R., and Gossenauer, M., 2004. Center pivot irrigation in Colorado as mapped by LANDSAT imagery: Colorado State University Agricultural Experiment Station Technical Bulletin TB04-04. Scott, J.C., 1990, Computerized stratified random site-selection approaches for design of a ground-water-quality sampling network: U.S. Geological Survey Water Resources Investigations Report 90-4101, 109 p. 2000 unknown ground condition Complete None planned -103.447988 -101.852740 40.783825 38.184084 None High Plains Aquifer inlandWaters None Eastern Colorado USA United States of America None None. Users of this geospatial database and geologic information derived there from should acknowledge the U.S. Geological Survey as the source of the data. U.S. Geological Survey Ask USGS -- Water Webserver Team mailing address

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Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ds472_equalareas Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.6.1500 US Geological Survey, Colorado Water Science Center 2009 Data Series 456 US Geological Survey 2003 Circular 1243 US Geological Survey 2007 Professional Paper 1749 US Geological Survey 1981 Hydrologic Investigations Atlas 648 Polygon shapefile created with aml described in Scott 1990. Checked against source data of saturated thickness, depth to water, and irrigated lands. Areas meeting criteria of saturated thickness greater than 50 ft, depth to water less than 180 ft, and irrigated lands were divided into 30 equal areas. Checked against source data of saturated thickness, depth to water, and irrigated lands. Checked against source data of saturated thickness, depth to water, and irrigated lands. Determined areas where the depth to water is less than 180 feet by selecting grid values of 180 or less from ds472_dtw and exporting to a polygon dataset. 2008 Determined areas where the saturated thickness is greater than or equal to 50 feet by selecting grid values of 50 or more from ds472_sat and exporting to a polygon dataset. 2008 Aggregated polygons of irrigated agricultural lands that are within 2000 meters of each other. Exported to a polygon dataset. Bauder, Troy, Cipra, Jan, Waskom, Reagan, and Gossenauer, Michael, 2004. Center pivot irrigation in Colorado as mapped by LANDSAT imagery: Colorado State University Agricultural Experiment Station Technical Bulletin TB04-04. 2008 Intersected datasets created in first 3 process steps: depth to water less than or equal to 180 feet, saturated thickness greater than or equal to 50 feet, and aggregated irrigated agricultural lands. Exported intersecting areas to a polygon dataset. 2008 Divided polygon datset from process step 4 into 30 equal areas as described in Scott 1990. Scott, J.C., 1990, Computerized stratified random site-selection approaches for design of a ground-water-quality sampling network: U.S. Geological Survey Water Resources Investigations Report 90-4101, 109 p. 2008 Vector G-polygon 305 Albers Conical Equal Area 29.500000 45.500000 -96.000000 23.000000 0.000000 0.000000 coordinate pair 0.00001 0.00001 meters North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 ds472_equalareas Equal area polygons Data Series 472 FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. CELL Identifier of equal area polygon Data Series 456 1 30 0 not applicable U.S. Geological Survey Ask USGS -- Water Webserver Team (http://ask.usgs.gov/) mailing address

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Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Downloadable Data 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 information product, for the most part, is in the public domain, it also contains copyrighted material as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. This database, identified as Equal-area polygons used in design and installation of a well network for long-term monitoring of agricultural chemicals in the High Plains Aquifer, Colorado, has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientififc purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. ESRI shapefile 0.354 http://water.usgs.gov/GIS/dsdl/ds472_equalareas.zip unzip None 20090504 US Geological Survey REQUIRED: The person responsible for the metadata information. Ask USGS -- Water Webserver Team mailing address

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Reston VA 20192 USA 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ds472_equalareas FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998