Prepared in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey Potentiometric Surfaces and Water-Level Trends in the Cockfield (Upper Claiborne) Aquifer in Southern Arkansas and the Wilcox (Lower Wilcox) Aquifer of Northeastern and Southern Arkansas, 2012 94º 93º MISSOURI 92º 91º ARKANSAS CLAY GREENE 90º 36º OZARK PLATEAUS CRAIGHEAD TENNESSEE MISSISSIPPI POINSETT OKLAHOMA Arkansas Valley S CROSS D N LA OUACHITA H G ST. FRANCIS I CRITTENDEN 35º PROVINCE IN H A PL LEE L A Mississippi Alluvial Plain INTERIORST Ouachita Mountains OA C Mississippi River HOT SPRING ARKANSAS GRANT MISSISSIPPI JEFFERSON 34º DALLAS CLEVELAND CLARK LINCOLN DESHA OUACHITA NEVADA DREW HEMPSTEAD CALHOUN TEXAS BRADLEY West Gulf Coastal Plain CHICOT ASHLEY COLUMBIA UNION LOUISIANA Scientific Investigations Report 2014–5232 U.S. Department of the Interior U.S. Geological Survey Potentiometric Surfaces and Water- Level Trends in the Cockfield (Upper Claiborne) Aquifer in Southern Arkansas and the Wilcox (Lower Wilcox) Aquifer of Northeastern and Southern Arkansas, 2012 By Kirk D. Rodgers Prepared in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey Scientific Investigations Report 2014–5232 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2015 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Rodgers, K.D., 2015, Potentiometric surfaces and water-level trends in the Cockfield (upper Claiborne) aquifer in southern Arkansas and the Wilcox (lower Wilcox) aquifer of northeastern and southern Arkansas, 2012: U.S. Geological Survey Scientific Investigations Report 2014–5232, 46 p., http://dx.doi.org/10.3133/sir20145232. ISSN 2328-0328 (online) iii Contents Abstract ..........................................................................................................................................................1 Introduction ....................................................................................................................................................2 Methods ..........................................................................................................................................................4 Water-Level Measurements ..............................................................................................................4 Linear Regression ................................................................................................................................4 Geographic Information Systems .....................................................................................................4 Cockfield (Upper Claiborne) Aquifer ..........................................................................................................6 Hydrogeologic Setting ........................................................................................................................6 Hydraulic Properties ..................................................................................................................6 Water Use ....................................................................................................................................8 Potentiometric Surface .......................................................................................................................9 Water-Level Trends .............................................................................................................................9 Water-Level Difference from 2006 to 2012 ..............................................................................9 Long-Term Hydrographs ..........................................................................................................12 Wilcox (Lower Wilcox) Aquifer .................................................................................................................19 Hydrogeologic Setting ......................................................................................................................19 Hydraulic Properties ................................................................................................................20 Water Use ..................................................................................................................................20 Potentiometric Surface .....................................................................................................................20 Water-Level Trends ...........................................................................................................................23 Water-Level Difference from 2006 to 2012 ............................................................................23 Long-Term Hydrographs ..........................................................................................................23 Summary .......................................................................................................................................................33 References Cited .........................................................................................................................................34 Appendixes 1. Water-level data collected during February 2012 from wells completed in the Cockfield aquifer in southern Arkansas .................................................................................39 2. Difference in depth to water from 2006 to 2012 in the Cockfield aquifer in southern Arkansas ....................................................................................................................41 3. Water-level data collected during February and March 2012 from wells completed in the Wilcox aquifer in northeastern Arkansas ...............................................42 4. Water-level data collected during February and March 2012 from wells completed in the Wilcox aquifer in southern Arkansas ......................................................43 5. Difference in depth to water from 2006 to 2012 in the Wilcox aquifer in northeastern Arkansas .............................................................................................................44 6. Difference in depth to water from 2006 to 2012 in the Wilcox aquifer in southern Arkansas .....................................................................................................................................45 iv Figures 1. Map showing location of study area of Cockfield aquifer in southern Arkansas and Wilcox aquifer in northeastern and southern Arkansas ...............................................3 2. Diagram showing well-numbering system ..............................................................................5 3. Diagram showing generalized section of the hydrogeologic and geologic units within the Mississippi Embayment ...........................................................................................8 4. Bar graph showing water use from the Cockfield aquifer in southern Arkansas, 1975–2010 ......................................................................................................................................8 5. Map showing potentiometric surface of the Cockfield aquifer in southern Arkansas, 2012 ...........................................................................................................................10 6. Map showing water-level difference for the Cockfield aquifer in southern Arkansas, 2006–12 .....................................................................................................................11 7. Water-level hydrographs for selected wells completed in the Cockfield aquifer in southern Arkansas ....................................................................................................................13 8. Bar graph showing water use from the Wilcox aquifer in Arkansas, 1975–2010 ...........20 9. Map showing potentiometric surface of the Wilcox aquifer in northeastern Arkansas, 2012 ...........................................................................................................................21 10. Map showing potentiometric surface of the Wilcox aquifer in southern Arkansas, 2012 ...........................................................................................................................22 11. Map showng water-level difference for the Wilcox aquifer in northeastern Arkansas, 2006–12 .....................................................................................................................24 12. Map showng water-level difference for the Wilcox aquifer in southern Arkansas, 2006–12 ........................................................................................................................................25