Digital data sets that describe aquifer characteristics of the Vamoosa-Ada aquifer in east-central Oklahoma

This data set consists of digitized polygons of constant
recharge 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Approximately 75 percent of the water withdrawn from the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withdrawn.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 recharge rate of the Vamoosa-Ada aquifer was estimated as
1.52 inches per year from base-flow measurements and
precipitation records published in a ground-water report. Most
of the recharge 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.