Water-level data, selected water-quality data, and the potentiometric dataset for the Mississippi River Valley alluvial aquifer in eastern Arkansas, spring 2014

The alluvial aquifer of the Mississippi embayment lies within a syncline plunging south towards the Gulf of Mexico with the axis of the syncline roughly following the Mississippi River (Cushing and others, 1964, Hart and others, 2008). The trough of the syncline is comprised of alluvial and terrace deposits of Quaternary age (Ackerman, 1996). A potentiometric-surface map of the Mississippi River Valley alluvial aquifer represents the altitude at which water would stand in tightly cased wells completed at any location within the study area (Schrader, 2015). Using the altitude of water levels measured in the study area, the potentiometric-surface map depicts points of equal altitude with contours denoting a given water level altitude. The contour lines were created using computer-based program ArcGIS by ESRI (Esri, 2011). Water levels collected in 2014 were use to interpolate water-level contour lines. The direction of water flow from areas of high elevation to low elevation can be interpreted using potentiometric-surface maps and areas of decreased groundwater levels can be identified. Potentiometric-surface maps provide decision makers with information regarding water-level changes over time and can aid in determining areas of increased water use. Ackerman, D.J., 1996, Hydrology of the Mississippi River Valley alluvial aquifer, south-central United States - A preliminary assessment of the regional flow system: U.S. Geological Survey Professional Paper 1416-D, 56 p. [Also available at https://pubs.er.usgs.gov/publication/wri884028] Cushing, E.M., Boswell, B.H., and Hosman, R.L., 1964, General geology of the Mississippi embayment: U.S. Geological Survey Professional Paper 448-B, 28 p. [Also available at http://pubs.usgs.gov/pp/0448b/report.pdf.] Esri, 2011, ArcGIS desktop - Release 10: Redlands, California, Environmental Systems Research Institute. Schrader, T.P., 2015, Water levels and selected water-quality conditions in the Mississippi River Valley alluvial aquifer in eastern Arkansas, 2012: U.S. Geological Survey Scientific Investigations Report 2015-5059, 70 p. available at https://pubs.usgs.gov/sir/2015/5059/