Becker, Carol J. Runkle, Donna Rea, Alan 1997 1.0 map Open-File Report 96-449 Reston, VA U.S. Geological Survey https://water.usgs.gov/lookup/getspatial?ofr96-449_recharg This data set consists of digitized polygons of constant recharge values for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately 193,000 acres and supplies ground water for irrigation, domestic, and industrial purposes in Beckham, Custer, Roger Mills, and Washita Counties along the divide between the Washita and Red River basins. The Elk City aquifer consists of the Elk City Sandstone and overlying terrace deposits, made up of clay, silt, sand and gravel, and dune sands in the eastern part and sand and gravel of the Ogallala Formation (or High Plains aquifer) in the western part of the aquifer. The Elk City aquifer is unconfined and composed of very friable sandstone, lightly cemented with clay, calcite, gypsum, or iron oxide. Most of the grains are fine-sized quartz but the grain size ranges from clay to cobble in the aquifer. The Doxey Shale underlies the Elk City aquifer and acts as a confining unit, restricting the downward movement of ground water. The recharge polygon boundaries were transfered from a figure in the ground-water model thesis for the Elk City aquifer to a photocopy of a paper map and digitized. The source map was published at a scale of 1:63,360. The Elk City aquifer was divided into three subareas based on soil type and topography and assigned the recharge rates 2.00, 3.92, and 4.00 inches per year in a ground-water model thesis. These subareas and recharge rates are used in this data set. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data. This data set was created for a project to develop data sets to support ground-water vulnerability analysis. The objective was to create and document a digital geospatial data set from a published report or map that could be used in ground-water vulnerability analysis. Introduction -- This data set consists of digitized polygons of constant recharge rates for the Elk City aquifer in western Oklahoma. The aquifer covers an area of approximately 193,000 acres and supplies ground water for irrigation, domestic, and industrial purposes in Beckham, Custer, Roger Mills, and Washita Counties along the divide between the Washita and Red River basins (Lyons, 1981). The Elk City aquifer consists of the Elk City Sandstone and overlying terrace deposits, made up of clay, silt, sand and gravel, and dune sands in the eastern part and sand and gravel of the Ogallala Formation (or High Plains aquifer) in the western part of the aquifer (Lyons, 1981). The Elk City aquifer is unconfined and composed of very friable sandstone, lightly cemented with clay, calcite, gypsum, or iron oxide. Most of the grains are fine-sized quartz but the grain size ranges from clay to cobble in the aquifer (Lyons, 1981). The Doxey Shale underlies the Elk City aquifer and acts as a confining unit, restricting the downward movement of ground water. The recharge polygon boundaries from the ground-water model thesis, "A ground-water management model for the Elk City aquifer in Washita, Beckham, Custer and Roger Mills Counties, Oklahoma," by Lyons (1981, figs. 26 and 27) were transferred to a photocopy of a paper map (plate 2) and digitized. The source map was published at a scale of 1:63,360. Recharge for the eastern part of the aquifer was calculated by Lyons (1981) to be 14.1 percent of the annual precipitation (27.80 inches) recorded at Clinton, Oklahoma, or 3.92 inches of recharge per year. Recharge for the western part of the aquifer was calculated by Lyons to be 14.1 percent of the annual precipitation recorded (22.97 inches) at Sayre, Oklahoma, or 3.24 inches per year of recharge. The years used to calculating the annual precipitation were not reported in the thesis. Lyons (1981) used a quarter-mile grid for the ground-water flow model and divided the aquifer into three subareas based on soil type and topography. The subareas were assigned the recharge rates 2.00, 3.92, or 4.00 inches per year. The subareas and assigned recharge rates used in the ground-water model thesis are used in this data set. These recharge rates also were used by Kent, Lyons, and Witz (1982) in a ground-water model of the Elk City aquifer. Digital Line Graph (DLG) format requires numbers to be stored as integers. Therefore, the recharge in inches per year was multiplied by 100 and stored in the digital data sets as hundredths of inches per year. For example 2.00 inches per year was multiplied by 100 and stored in the digital data sets as 200 hundredths of an inch per year Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. The hydraulic conductivity and recharge are closely interrelated. As long as these two model inputs are in balance the model has a small mean residual; it represents the natural system numerically. If the hydraulic conductivity is accurately known, the model can be used to accurately determine recharge. Likewise, if the hydraulic conductivity is poorly known, then the recharge will be poorly determined. Therefore, values of recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data. Recharge probably varies considerably over the local area, and model recharge is at best an average over an area at least as large as the model grid (and probably much larger than a single cell). 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 and paper plots for checking against the source maps to verify the linework and attributes. The reviewers checked the metadata and a_readme.1st files for completeness and accuracy. Related Spatial and Tabular Data Sets -- This data set is one of four digital map data sets being published together for this aquifer. The four data sets are: > aqbound - aquifer boundaries > cond - hydraulic conductivity > recharg - aquifer recharge > wlelev - water-level elevation contours Digital map data sets of the Oklahoma surficial geology digitized from 1:250,000-scale maps (or 1:125,000-scale maps for the three Oklahoma panhandle counties) are published separately. Other References Cited -- Environmental Systems Research Institute, Inc. (ESRI), 1995, ARC/INFO Command Reference, ARC/INFO On-line manuals: Redlands, CA. Kent, D.C., Lyons T.D., and Witz, F.E., 1982, Evaluation of aquifer performance and water supply capabilities of the Elk City aquifer in Washita, Beckham, Custer, and Roger Mills Counties, Oklahoma: Stillwater, OK, Department of Geology, Oklahoma State University report, 96 p., 29 figs. (Final report to the Oklahoma Water Resources Board) Lyons, T.D., 1981, A ground-water management model for the Elk City aquifer in Washita, Beckham, Custer and Roger Mills Counties, Oklahoma: Stillwater, OK, Oklahoma State University, master's thesis, 88 p., 2 pls., 43 figs. 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. 1981 publication date Complete None planned -99.6799 -99.0740 35.5458 35.2192 USGS Thesaurus ground-water vulnerability groundwater vulnerability aquifers ground water groundwater Elk City aquifer Elk City Sandstone recharge recharge rate ground-water recharge inlandWaters ISO 19115 Topic Category geoscientificInformation inlandWaters environment USGS Metadata Identifier USGS:859366e6-d88c-48d9-bf0a-1ea171d7664b Geographic Names Information System western Oklahoma None. This data set was digitized from a photocopy of map published at a scale of 1:63,360, and represents the recharge polygons as reported by Lyons (1981). Recharge polygons represented at this scale are indicative of broad, regional trends and should not be interpreted as site-specific. The recharge polygons were drawn onto and digitized from a plate size, 29 inches by 39 inches, paper map, with a root-mean-squared-error (RMSE) of 0.017 map inches (0.043 map centimeters) and 55.8 feet (17 meters) ground distance. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. The hydraulic conductivity and recharge are closely interrelated. As long as these two model inputs are in balance the model has a small mean residual; it represents the natural system numerically. If the hydraulic conductivity is accurately known, the model can be used to accurately determine recharge. Likewise, if the hydraulic conductivity is poorly known, then the recharge will be poorly determined. Therefore, values of recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data. Recharge probably varies considerably over the local area, and model recharge is at best an average over an area at least as large as the model grid (and probably much larger than a single cell). Carol J. Becker U.S. Geological Survey Hydrologist mailing address

202 NW 66th St., Bldg. 7

Oklahoma City Oklahoma 73116 United States of America 1-888-275-8747 (405) 843-7712 cjbecker@usgs.gov none https://water.usgs.gov/GIS/browse/ofr96-449.gif A browse image of the four aquifer data sets. GIF Compilation of this data set and the associated metadata was funded under a cooperative Joint Funding Agreement between the U.S. Geological Survey, and the State of Oklahoma, Office of the Secretary of Environment. Public UNCLASSIFIED None Operating System-- UNIX, ARC/INFO Version 7.0.3,(Mon Mar 13 22:21:55 PST 1995) Polygon and chain-node topology present. This data set includes all the areas of specified recharge rates as reported by Lyons (1981) on pages 56 and 57, figures 26 and 27, respectively. None 16 meters Resolution as reported None. A tic data set was created using 1:250,000-scale U.S. Geological Survey quadrangle maps. 19960314 The recharge polygons from Lyons (1981, figs. 26 and 27) were transferred to a paper map. The recharge polygons were digitized in one session with a maximum registration root-mean-squared error (RMSE) of 0.017 map inches (0.043 centimeters) and 88.6 feet (27 meters) ground distance. The data set was edited and the ARC/INFO command CLEAN (ESRI, 1995) was used with a dangle length of 114.8 feet (35 meters) ground distance and a fuzzy tolerance of 16.4 feet (5 meters) ground distance. 19960412 Polygons were attributed for AQTYPE and lines were attributed for LSOURCE. The data set was documented. 19960415 Vector Point 30 String 79 GT-polygon composed of chains 31 Albers Conical Equal Area 45.5 45.5 -96 23 0.0 0.0 coordinate pair 16 meters 16 meters METERS North American Datum of 1983 Geodetic Reference System 80 6378137 298.257 RECHARG.PAT Polygon attribute table ARC/INFO - Polygon attribute table ARC/INFO - n/a n/a AREA Area of polygon in square coverage units Computed Positive real numbers n/a n/a PERIMETER Perimeter of polygon in coverage units Computed Positive real numbers n/a n/a RECHARG# Internal feature number Computed Sequential unique positive integer n/a n/a RECHARG-ID User-assigned feature number User-defined Integer n/a n/a R Recharge, in hundredths of an inch per year Lyons (1981) 200, 392, 400 n/a n/a MINOR1 Blank item for DLG Calculated 0 n/a n/a MAJOR1 Recharge, in hundredths of an inch per year Lyons (1981) 200, 392, 400 n/a n/a RECHARG.AAT Arc attribute table ARC/INFO - Arc attribute table ARC/INFO - n/a n/a FNODE# Internal number of from-node Computed Sequential unique positive integer n/a n/a TNODE# Internal number of to-node Computed Sequential unique positive integer n/a n/a LPOLY# Internal number of poly to left of arc Computed Sequential unique positive integer n/a n/a RPOLY# Internal number of poly to right of arc Computed Sequential unique positive integer n/a n/a LENGTH Length of arc in coverage units Computed Positive real numbers n/a n/a RECHARG# Internal feature number Computed Sequential unique positive integer n/a n/a RECHARG-ID User-assigned feature number User-defined Integer n/a n/a LSOURCE Source of line Lyons (1981) 1 n/a n/a MINOR1 Blank item for DLG Calculated 0 n/a n/a MAJOR1 Source of line Lyons (1981) 1 n/a n/a Each polygon in this data set has an associated attribute, R, containing values of recharge (Lyons, 1981) expressed in hundredths of an inch per year. For example, the recharge value of 2.00 inches per year is stored as an R value of 200. R is stored in the first major code (MAJOR1) for polygons, and 0 is stored in the first minor code (MINOR1) in the Digital Line Graph (DLG) version of this data set. Each line in this digital data set has an associated attribute, LSOURCE, that contains a code to indicate the source of the line. An LSOURCE code of 1 indicates the line was digitized from Lyons (1981). LSOURCE is stored in the first major code (MAJOR1) for lines, and 0 is stored in the first minor code (MINOR1) in the Digital Line Graph (DLG) version of this data set. See overview. U.S. Geological Survey Michael Ierardi IT Specialist mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov 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 https://water.usgs.gov/GIS/dsdl/ofr96-449_recharg.e00.gz Other DLG file format zipped 1 https://water.usgs.gov/GIS/dsdl/ofr96-449_recharg.dlg.gz None. This dataset is provided by USGS as a public service. 20201117 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) mierardi@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998