Abbott, Marvin M. Runkle, Donna Rea, Alan 1997 1.0 map Open-File Report 96-443 Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ofr96-443_cond This data set consists of digitized polygons of a constant hydraulic conductivity value for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers Sandstone is an important source of water in an area that underlies about 4,400-square miles of all or part of Atoka, Bryan, Carter, Choctaw, Johnston, Love, Marshall, McCurtain, and Pushmataha Counties. The Antlers aquifer consists of sand, clay, conglomerate, and limestone in the outcrop area. The upper part of the Antlers aquifer consists of beds of sand, poorly cemented sandstone, sandy shale, silt, and clay. The Antlers aquifer is unconfined where it outcrops in about an 1,800-square-mile area. The hydraulic conductivity polygons were developed from the hydraulic conductivity value used as input into a ground-water flow model and from published digital data sets of the surficial geology of the Antlers Sandstone except in areas overlain by alluvial and terrace deposits near streams. Some of the lines were interpolated where the Antlers aquifer is overlain by alluvial and terrace deposits. The interpolated lines are very similar to the aquifer boundaries shown on maps published in a ground-water modeling report for the Antlers aquifer. The constant hydraulic conductivity value used as input to the ground-water flow model was estimated as 5.74 feet per day. 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 hydraulic conductivity 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, or existing digital geospatial data set that could be used in ground-water vulnerability analysis. Introduction -- This data set consists of digitized polygons of constant hydraulic conductivity values for the Antlers aquifer in southeastern Oklahoma. The Early Cretaceous-age Antlers Sandstone is an important source of water in an area that underlies about 4,400-square miles of all or part of Atoka, Bryan, Carter, Choctaw, Johnston, Love, Marshall, McCurtain, and Pushmataha Counties. The Antlers aquifer consists of sand, clay, conglomerate, and limestone in the outcrop area. The upper part of the Antlers aquifer consists of beds of sand, poorly cemented sandstone, sandy shale, silt, and clay. The Antlers aquifer is unconfined where it outcrops in about an 1,800-square-mile area (Morton, 1992). The hydraulic conductivity polygons were developed from the hydraulic conductivity value used as input into a ground-water flow model and from digital data of the surficial geology of the Antlers Sandstone from Cederstrand (1996a, 1996b) except in areas overlain by alluvial and terrace deposits near streams and rivers. Morton (1992) interpolated the Antlers aquifer boundaries under the alluvial and terrace deposits where streams cross the aquifer outcrop. Aquifer boundary lines for areas where the aquifer is overlain by alluvial and terrace deposits were digitized and are similar to the aquifer boundaries shown in Morton (1992). The Antlers aquifer in Texas (Morton, 1992) is not included in this data set. The maps from which this data set was derived were published at a scale of 1:250,000. The constant hydraulic conductivity value used as input to the ground-water flow model was estimated by Morton (1992) to be 5.74 feet per day. Digital Line Graph (DLG) format requires numbers to be stored as integers. Therefore, the hydraulic conductivity in feet per day was multiplied by 10, rounded to the nearest whole number, and stored in the digital data sets as tenths of a foot per day. For example 5.74 feet per day was multiplied by 10, rounded to the nearest whole number, and stored in the digital data sets as 57 tenths of a foot per day. 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 hydraulic conductivity 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. In most aquifers, hydraulic conductivity measurements made in wells or in cores will range over several orders of magnitude, even over short horizontal and vertical distances. Hydraulic conductivity values derived from ground-water flow models represent areal generalizations and do not reflect the large local variance in well or core measurements. 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 -- Cederstrand, J.R., 1996a, Digital geologic map of the Ardmore-Sherman quadrangles, south-central Oklahoma: U.S. Geological Survey Open-File Report 96-370, based on a scale of 1:250,000, 3 diskettes. (Available in nonproprietary and ARC/INFO formats.) URL: http://wwwok.cr.usgs.gov/gis/geology/index.html Cederstrand, J.R., 1996b, Digital geologic map of McAlester-Texarkana quadrangles, southeastern Oklahoma: U.S. Geological Survey Open-File Report 96-377, based on a scale of 1:250,000, 3 diskettes. (Available in nonproprietary and ARC/INFO formats.) URL: http://wwwok.cr.usgs.gov/gis/geology/index.html Morton, R.B., 1992, Simulation of ground-water flow in the Antlers aquifer in southeastern Oklahoma and northeastern Texas: U.S. Geological Survey Water-Resources Investigations Report 88-4208, 22 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. 1992 publication date Complete None planned -97.4976 -94.4684 34.3644 33.7288 none ground-water vulnerability groundwater vulnerability aquifers ground water groundwater Antlers aquifer Antlers Sandstone hydraulic conductivity inlandWaters none southeastern Oklahoma None This data set was derived from scanned maps published at a scale of 1:250,000 (Cederstrand, 1996a and 1996b), and represent the hydraulic conductivity value reported in Morton (1992). Hydraulic conductivity polygons represented at this scale are indicative of broad, regional trends and should not be interpreted as site specific. 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 hydraulic conductivity 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. In most aquifers, hydraulic conductivity measurements made in wells or in cores will range over several orders of magnitude, even over short horizontal and vertical distances. Hydraulic conductivity values derived from ground-water flow models represent areal generalizations and do not reflect the large local variance in well or core measurements. Marvin M. Abbott 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 mmabbott@usgs.gov none http://water.usgs.gov/lookup/get?OFR96-443/browse.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) Cederstrand, Joel R. 1996 1.0 map Open-File Report 96-370 Oklahoma City, OK U.S. Geological Survey http://ok.water.usgs.gov/gis/geology/ Cederstrand, Joel R. 1996 1.0 map Open-File Report 96-377 Oklahoma City, OK U.S. Geological Survey http://ok.water.usgs.gov/gis/geology/ Polygon and chain-node topology present. This data set includes all the areas of specified hydraulic conductivity published by Morton (1992) for the unconfined part of the aquifer. The Antlers aquifer in Texas (Morton, 1992) is not presented in this publication. This data set includes all the aquifer boundaries for the unconfined part of the aquifer published by Cederstrand (1996a, 1996b) except where the aquifer is covered by alluvial and terrace deposits (Cederstrand, 1996b). Some of the lines were interpolated where the Antlers aquifer is overlain by alluvial and terrace deposits near streams and rivers and are similar to the aquifer boundaries on maps in Morton (1992). The polygons in this data set include the aquifer under the alluvial and terrace deposits to represent the aquifer as presented in Morton (1992). The Antlers aquifer in Texas (Morton, 1992) is not included in this data set. None Unknown Resolution as reported None. The polygons are from Cederstrand (1996a, 1996b) except near the streams and rivers that present alluvial and terrace deposits. Morton (1992) interpolated the aquifer boundaries under the alluvial and terrace deposits where streams cross the aquifer outcrop. The polygons in this report also include the aquifer under the alluvial and terrace deposits to present the aquifer similar to Morton (1992). The geologic contacts on the digital geologic map (Cederstrand, 1996b) and the aquifer boundary map (Morton, 1992) are slightly different. 1996 See Cederstrand (1996a, 1996b) 1996 Vector Point 134 String 268 GT-polygon composed of chains 135 Albers Conical Equal Area 29.5 45.5 -96 23 0.0 0.0 coordinate pair Unknown Unknown METERS North American Datum of 1983 Geodetic Reference System 80 6378137 298.257 COND.PAT Polygon attribute table ARC/INFO - Polygon attribute table ARC/INFO - n/a n/a AREA Area of poly/region in square coverage units Computed Positive real numbers n/a n/a PERIMETER Perimeter of poly/region in coverage units Computed Positive real numbers n/a n/a COND# Internal feature number Computed Sequential unique positive integer n/a n/a COND-ID User-assigned feature number User-defined Integer n/a n/a K Hydraulic conductivity in tenths of a foot per day Morton (1992) 57 n/a n/a MINOR1 Blank item for DLG Calculated 0 n/a n/a MAJOR1 Hydraulic conductivity in tenths of a foot per day Morton (1992) 57 n/a n/a COND.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 COND# Internal feature number Computed Sequential unique positive integer n/a n/a COND-ID User-assigned feature number User-defined Integer n/a n/a LSOURCE Source of line Cederstrand (1996a, 1996b), Author, Abbottt, Marvin M. 2,4 n/a n/a MINOR1 Blank item for DLG Calculated 0 n/a n/a MAJOR1 Source of line Cederstrand (1996a, 1996b), Author, Abbottt, Marvin M. 2,4 n/a n/a Each polygon in this data set has an associated attribute, K, containing rounded values of hydraulic conductivity expressed in tenths of a foot per day. For example, the hydraulic conductivity value of 5.74 feet per day is rounded to 5.7 and stored as a K value of 5.7 tenths of a foot per day. Polygons in this data set that contain a K value of -99999 represent areas where the hydraulic conductivity is not known. K is stored in the first major code (MAJOR1) and 0 is stored in the first minor code (MINOR1) for polygons 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 2 indicates the line was extracted from Cederstrand (1996a, 1996b), and an LSOURCE code of 4 indicates the line is the authors' interpretation of the boundary where the aquifer is overlain by alluvial or terrace deposits, similar to Morton (1992). LSOURCE is stored in the first major code (MAJOR1) and 0 is stored in the first minor code (MINOR1) for lines in the Digital Line Graph (DLG) version of this data set. See overview. 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+ofr96-443_cond 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/ofr96-443_cond.e00.gz Other DLG file format zipped 1 http://water.usgs.gov/GIS/dsdl/ofr96-443_cond.dlg.gz 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+ofr96-443_cond FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998