Publications—Scientific Investigation Report

Potentiometric Surface of the Ozark Aquifer in Northern Arkansas, 2004

By T.P. Schrader

U.S. Geological Survey Scientific Investigations Report 2005-5208—ONLINE ONLY

This document is available in Portable Document Format (PDF):  SIR2005-5208 (1.59 MB)
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The Ozark aquifer in northern Arkansas comprises dolomites, limestones, sandstones, and shales of Late Cambrian to Middle Devonian age, and ranges in thickness from approximately 1,100 feet to more than 4,000 feet. Hydrologically, the aquifer is complex, characterized by discrete and discontinuous flow components with large variations in permeability.

The potentiometric-surface map, based on 59 well and 5 spring water-level measurements collected in 2004 in Arkansas and Missouri, indicates maximum water-level altitudes of about 1,188 feet in Benton County and minimum water-level altitudes of about 116 feet in Randolph County. Regionally, the flow within the aquifer is to the south and southeast in the eastern and central part of the study area and to the northwest and north in the western part of the study area. Comparing the 2004 potentiometric- surface map with a predevelopment potentiometricsurface map indicates general agreement between the two surfaces. Potentiometric-surface differences could be attributed to differences in pumping related to changing population from 1990 to 2000, change in source for public supplies, processes or water use outside the study area, or differences in data-collection or map-construction methods.


  1. Map showing potentiometric surface of the Ozark aquifer in northern Arkansas, 2004
  1. Map showing location of study area
  2. Map showing location of Ozark Plateaus aquifer system
  1. Stratigraphic column with descriptions of lithologic and geohydrologic properties of the Ozark aquifer and adjacent confining units within Arkansas
  2. Information pertaining to measured wells and springs in the Ozark aquifer in northwestern Arkansas and southcentral Missouri, 2004


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