Digital data sets that describe aquifer characteristics of the Rush Springs aquifer in western Oklahoma

This data set consists of digitized polygons of constant
hydraulic conductivity values for the Rush Springs aquifer in
western Oklahoma. This area encompasses all or part of
Blaine, Caddo, Canadian, Comanche, Custer, Dewey, Grady,
Stephens, and Washita Counties. For the purposes of modeling
the ground-water flow in the Rush Springs aquifer, Mark F.
Becker (U.S. Geological Survey, written commun., 1997)
defined the Rush Springs aquifer to include the Rush Springs
Formation, alluvial and terrace deposits along major streams,
and parts of the Marlow Formations, particularly in the
eastern part of the aquifer boundary area.

The Permian-age Rush Springs Formation consists of highly
cross-bedded sandstone with some interbedded dolomite and
gypsum. The Rush Springs Formation is overlain by
Quaternary-age alluvial and terrace deposits that consist of
unconsolidated clay, silt, sand, and gravel. The Rush Springs
Formation is underlain by the Permian-age Marlow Formation
that consists of interbedded sandstones, siltstones,
mudstones, gypsum-anhydrite, and dolomite beds (Mark F.
Becker, written commun., 1997). The parts of the Marlow
Formation that have high permeability and porosity are where
the Marlow Formation is included as part of the Rush Springs
aquifer.

The Rush Springs aquifer underlies about 2,400 square miles
of western Oklahoma and is an important source of water for
irrigation, livestock, industrial, municipal, and domestic
use. Irrigation wells are reported to have well yields
greater than 1,000 gallons per minute (Mark F. Becker,
written commun., 1997).

The hydraulic conductivity values used by Mark F. Becker
(written commun., 1997) to simulate the ground-water flow in
the Rush Springs aquifer are 0.8, 2.0, 4.0, 8.0, and 10.0
feet per day. The hydraulic conductivity values are based on
specific capacity data and aquifer tests. Mark F. Becker
created some of the hydraulic conductivity data set by
digitizing parts of previously published surficial geology
maps.

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.

本数据集包含俄克拉荷马州西部拉什斯普林斯含水层（Rush Springs aquifer）的恒定导水率值数字化多边形数据。该区域涵盖布莱恩县、卡多县、加拿大县、科曼奇县、卡斯特县、杜威县、格雷迪县、斯蒂芬斯县以及沃希托县的全部或部分辖区。为模拟拉什斯普林斯含水层的地下水流，马克·F·贝克尔（美国地质调查局，U.S. Geological Survey，1997年书面沟通）将该含水层定义为包含拉什斯普林斯地层、沿主要溪流分布的冲积与阶地沉积物，以及马洛地层的部分区域——尤其是含水层边界区域的东部地带。

二叠纪时期的拉什斯普林斯地层以发育强烈交错层理的砂岩为主，夹有少量白云岩与石膏夹层。拉什斯普林斯地层之上覆有第四纪冲积与阶地沉积物，其成分为未固结的黏土、粉砂、砂与砾石。拉什斯普林斯地层之下伏有二叠纪时期的马洛地层，该地层由互层状的砂岩、粉砂岩、泥岩、石膏-硬石膏以及白云岩层构成（马克·F·贝克尔，1997年书面沟通）。马洛地层中渗透率与孔隙度较高的区域，被纳入拉什斯普林斯含水层的组成部分。

拉什斯普林斯含水层覆盖俄克拉荷马州西部约2400平方英里的区域，是用于灌溉、畜牧、工业、市政及民用供水的重要水源。据报告，灌溉井的单井出水量超过1000加仑每分钟（马克·F·贝克尔，1997年书面沟通）。

马克·F·贝克尔（1997年书面沟通）用于模拟拉什斯普林斯含水层地下水流的导水率值分别为0.8、2.0、4.0、8.0及10.0英尺/天。该导水率值基于单位涌水量数据与含水层抽水试验结果得出。马克·F·贝克尔通过数字化已发表的部分表层地质图，创建了本数据集的部分导水率数据。

地下水流模型是对自然系统进行简化与聚合的数值表征。此类模型并非唯一解：含水层特征的不同组合可能得到相似的模拟结果。因此，本数据集收录的、用于该模型的导水率值并非精确值，但相较于独立采集的实测数据，其处于合理的取值范围内。