Becker, Carol J.
Runkle, Donna
Rea, Alan
1997
Digital data sets that describe aquifer characteristics of the Elk City aquifer in western Oklahoma
1.0
map
OpenFile Report
96449
Reston, VA
U.S. Geological Survey
http://water.usgs.gov/lookup/getspatial?ofr96449_cond
This data set consists of digitized polygons of constant
hydraulic conductivity 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
finesized 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.
Values of hydraulic conductivity used as input to the
groundwater flow model and in this data set are: 50 gallons per
day per foot squared or 6.7 feet per day for the Elk City
Sandstone; 500 gallons per day per foot squared or 66.8 feet per
day for the Quaternary terrace deposits and dune sand; and 750
gallons per day per foot squared or 100.3 feet day for the
Ogallala Formation.
The hydraulic conductivity polygons from a groundwater modeling
thesis were transferred to a photocopy of a paper map and
digitized. The source map was published at a scale of 1:63,360.
Groundwater 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 groundwater 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 groundwater
vulnerability analysis.
Introduction 
This data set consists of digitized polygons of constant
hydraulic conductivity 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 (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 finesized 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 terms permeability and permeability coefficient are used by
Lyons (1981) when referring to hydraulic conductivity. Hydraulic
conductivity is a more accepted term and is used in this report.
Values of hydraulic conductivity used by Lyons (1981) as input
to the groundwater flow model and included in this data set for
the Elk City aquifer are: 50 gallons per day per foot squared or
6.7 feet per day for the Elk City Sandstone; 500 gallons per day
per foot squared or 66.8 feet per day for the Quaternary terrace
deposits and dune sand; and 750 gallons per day per foot squared
or 100.3 feet day for the Ogallala Formation. For this report
the values of hydraulic conductivity are assigned to the
polygons shown by Lyons (1981, figs. 11 and 12). Lyons used a
quartermile grid and the weighted average hydraulic
conductivity where the Elk City Sandstone is overlain by
Quaternary deposits or by the Ogallala Formation. Kent, Lyons,
and Witz (1982) used the same hydraulic conductivity polygons,
but used permeabilities of 55 gallons per day per foot squared
or 7.4 feet per day for the western part of the aquifer and 62
gallons per day per foot squared or 8.3 feet per day for the
eastern part of the aquifer.
Digital Line Graph (DLG) format requires numbers to be stored as
integers. Therefore, the hydraulic conductivity in feet per day
was multiplied by 10 and stored in the digital data sets as
tenths of a foot per day. For example 66.8 feet per day was
multiplied by 10 and stored in the digital data sets as 668
tenths of a foot per day.
The hydraulic conductivity polygons from the groundwater
modeling thesis, "A groundwater management model for the Elk
City aquifer in Washita, Beckham, Custer and Roger Mills
Counties, Oklahoma," by Lyons (1981, figs 11 and 12) 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.
Groundwater 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 groundwater 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  waterlevel elevation contours
Digital map data sets of the Oklahoma surficial geology digitized from
1:250,000scale maps (or 1:125,000scale 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 Online 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 groundwater 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
None planned
99.6799
99.0740
35.5458
35.2192
none
groundwater vulnerability
groundwater vulnerability
aquifers
ground water
groundwater
Elk City aquifer
Elk City Sandstone aquifer
Elk City Sandstone
hydraulic conductivity
permeability
permeability coefficent
coefficent of permeability
inlandWaters
none
western Oklahoma
None.
This data set was digitized from a photocopy of a map published
at a scale of 1:63,360, and represents the hydraulic
conductivity polygons as reported by Lyons (1981). Hydraulic
conductivity polygons represented at this scale are indicative
of broad, regional trends and should not be interpreted as
sitespecific. The hydraulic conductivity polygons were drawn
onto and digitized from a plate size, 29 inches by 39 inches,
paper material, with a
maximum registration rootmeansquared error (RMSE) of 0.016 map
inches (0.041 map centimeters) and 82 feet (25 meters) ground
distance.
Groundwater 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 groundwater flow
models represent areal generalizations and do not reflect the
large local variance in well or core measurements.
Carol J. Becker
U.S. Geological Survey
Hydrologist
mailing address
202 NW 66th St., Bldg. 7
Oklahoma City
Oklahoma
73116
United States of America
18882758747
(405) 8437712
cjbecker@usgs.gov
none
http://water.usgs.gov/GIS/browse/ofr96449.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 chainnode topology present.
This data set includes all the values of hydraulic conductivity
published on pages 27 and 28 and the areas of specified
hydraulic conductivity published on figures 11 and 12 by Lyons
(1981).
None
16 meters
Resolution as reported
None.
The hydraulic conductivity polygons shown by Lyons (1981,
figs. 11 and 12) were transferred to a photocopy of a paper
map (plate 2). A tic data set was created using 1:250,000scale
U.S. Geological Survey quadrangle maps. Five tics were
registered on the source map and the hydraulic conductivity
polygons were digitized in one session with a maximum
registration rootmeansquareerror (RMSE) of of 0.016 map
inches (0.041 map centimeters) and 85.3 feet (26 meters)
ground distance.
19960314
The data set was edited and the ARC/INFO CLEAN command (ESRI,
1995) was used with a dangle length of 32.8 feet (10 meters)
ground distance and a fuzzy tolerance of 6.6 feet (2 meters)
ground distance.
19960315
Polygons were attributed for K and lines were attributed for
LSOURCE. The data set was plotted and compared to source map
for accuracy.
19960329
The data set was documented.
19960424
The data set was edited and the ARC/INFO CLEAN command (ESRI,
1995) was used with a dangle length of 49.2 feet (15 meters)
ground distance and a fuzzy tolerance of 49.2 feet (15 meters)
ground distance.
19960823
Vector
Point
5
String
10
GTpolygon composed of chains
6
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
COND.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
COND#
Internal feature number
Computed
Sequential unique positive integer
n/a
n/a
CONDID
Userassigned feature number
Userdefined
Integer
n/a
n/a
K
Hydraulic conductivity in tenths of a foot per day
Lyons (1981)
67, 668, 1003
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
Lyons (1981)
67, 668, 1003
n/a
n/a
COND.AAT
Arc attribute table
ARC/INFO

Arc attribute table
ARC/INFO

n/a
n/a
FNODE#
Internal number of fromnode
Computed
Sequential unique positive integer
n/a
n/a
TNODE#
Internal number of tonode
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
CONDID
Userassigned feature number
Userdefined
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, K,
containing values of hydraulic conductivity (Lyons, 1981)
expressed in tenths of a foot per day. For example, the
hydraulic conductivity of 66.8 feet per day is stored as a K
value of 668. K 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
Ask USGS  Water Webserver Team
mailing
445 National Center
Reston
VA
20192
18882758747 (1888ASKUSGS)
http://answers.usgs.gov/cgibin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ofr96449_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/ofr96449_cond.e00.gz
Other
DLG file format
zipped
1
http://water.usgs.gov/GIS/dsdl/ofr96449_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
445 National Center
Reston
VA
20192
18882758747 (1888ASKUSGS)
http://answers.usgs.gov/cgibin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ofr96449_cond
FGDC Content Standards for Digital Geospatial Metadata
FGDCSTD0011998