The Sparta-Memphis aquifer is the most widely used aquifer in the Mississippi Embayment for industrial and public supply. In the spring of 2007 the USGS measured 745 wells in six states that are completed in the Sparta-Memphis aquifer. This effort was a part of the ongoing Mississippi Embayment Regional Aquifer Study (MERAS)—partly to help with the calibration of a regional ground-water flow model of the Embayment and partly to construct a potentiometric-surface map of the Sparta-Memphis aquifer. The number of wells measured in Arkansas was 311, 7 were in Kentucky, 117 in Louisiana, 144 in Mississippi, 6 in Missouri, and 160 in Tennessee.  Thirty-five additional control points were derived from water-surface altitudes in streams in areas where the Sparta-Memphis aquifer outcrops.

Water-levels contours in the Sparta-Memphis potentiometric-surface map depict 13 large areas of depression, 5 are in Arkansas centered in Calhoun, Drew, Jefferson, Poinsett, and Union Counties; 3 are in Louisiana centered in Jackson, Ouachita, and Winn Parishes; 4 are in Mississippi centered in Bolivar, Hinds, Washington, and Yazoo Counties 1 is centered in Shelby County, Tennessee.

Hydrologic connection between the Sparta-Memphis aquifer in western Cross and Poinsett Counties in Arkansas and the overlying Mississippi River Valley alluvial aquifer has been suggested and implied in past studies. Recent geophysical log analysis indicates that in this area the Cook Mountain Formation of Claiborne Group (a confining unit) is absent and the Sparta-Memphis aquifer subcrops directly beneath the alluvial aquifer. In this area, analysis of water levels from both the Sparta-Memphis and the alluvial aquifers has impacted the altitude and the shape of contours in the Sparta-Memphis potentiometric-surface map.