Digital data sets that describe aquifer characteristics of the Antlers aquifer in southeastern Oklahoma

This data set consists of digitized polygons of constant
recharge 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.

The recharge polygons were developed from recharge rates 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 recharge rates used as input
to the ground-water flow model were 0.32 inches per year for the
western portion of the aquifer and 0.96 inches per year for the
eastern portion of the aquifer.

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.

本数据集包含俄克拉荷马州东南部安特勒斯含水层（Antlers aquifer）的恒定补给值数字化多边形。早白垩世时期的安特勒斯砂岩是一片约4400平方英里区域的重要供水来源，该区域覆盖阿塔卡县、布莱恩县、卡特县、乔克托县、约翰斯顿县、洛夫县、马歇尔县、麦柯蒂县以及普什马塔哈县的全部或部分区域。安特勒斯含水层露头区由砂、黏土、砾岩和石灰岩组成。安特勒斯含水层上部由砂层、胶结程度较差的砂岩、砂质页岩、粉砂和黏土构成。在约1800平方英里的露头区域内，安特勒斯含水层为无压含水层。

本补给多边形数据集源自作为地下水流模型（ground-water flow model）输入参数的补给速率，以及安特勒斯砂岩表层地质已发布的数字化数据集，溪流附近被冲积和阶地沉积覆盖的区域除外。在安特勒斯含水层被冲积和阶地沉积覆盖的区域，部分边界线通过插值得到。这些插值得到的边界线与安特勒斯含水层地下水流建模报告中发布的地图所展示的含水层边界高度一致。作为地下水流模型输入参数的恒定补给速率为：含水层西部区域每年0.32英寸，东部区域每年0.96英寸。

地下水流模型是对自然系统进行简化与聚合的数值表征。模型并非唯一，含水层特征的不同组合可能得到相似的模拟结果。因此，本数据集所采用并展示的模型补给速率并非精确值，但与独立采集的实测数据相比，其处于合理的取值范围之内。