Digital hydraulic conductivity values of the Vamoosa-Ada aquifer in east-central Oklahoma

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 sets that could be used in ground-water vulnerability analysis.

This data set consists of digitized polygons of constant hydraulic conductivity
values for the Vamoosa-Ada aquifer in east-central Oklahoma. The Vamoosa-Ada
aquifer is an important source of water that underlies about 2,320-square miles
of parts of Osage, Pawnee, Payne, Creek, Lincoln, Okfuskee, and Seminole
Counties. Approximately 75 percent of the water withdrawn from the Vamoosa-Ada
aquifer is for municipal use. Rural domestic use and water for stock animals
account for most of the remaining water withdrawn. The Vamoosa-Ada aquifer is
defined in a ground-water report as consisting principally of the rocks of the
Late Pennsylvanian-age Vamoosa Formation and overlying Ada Group. The
Vamoosa-Ada aquifer consists of a complex sequence of fine- to very
fine-grained sandstone, siltstone, shale, and conglomerate interbedded with
very thin limestones. The water-yielding capabilities of the aquifer are
generally controlled by lateral and vertical distribution of the sandstone beds
and their physical characteristics. The Vamoosa-Ada aquifer is unconfined where
it outcrops in about an 1,700-square-mile area.

The hydraulic conductivity of the Vamoosa-Ada aquifer was computed as 3 feet
per day in a ground-water report. Most of the hydraulic conductivity polygons
were extracted from published digital geology data sets. The lines in the
digital geology data sets were scanned or digitized from maps published at a
scale of 1:250,000 and represent geologic contacts. Some of the lines in the
data set were interpolated in areas where the Vamoosa-Ada aquifer is overlain
by alluvial and terrace deposits near streams and rivers.