Digitized Maps of the Potentiometric Surface of the Sparta Aquifer in North-Central Louisiana, 1886 to 2012 (ver. 1.1, April 2021)

The Sparta aquifer is a primary source of groundwater in north-central Louisiana with more than 60 million gallons of water per day being withdrawn in 2015, and public supply and Industry account for over 90 percent of the water-use demand from the Sparta aquifer (Collier, 2018). Concentrated withdrawals from the Sparta aquifer have caused regional water-level declines within the Sparta aquifer (McGee and Brantly, 2015). Widespread concern about the potential effects of declining water levels has brought forth many questions regarding the sustainability of the aquifer as well as continued saltwater intrusion. In cooperation with the Louisiana Department of Transportation and Development, the U.S. Geological Survey (USGS) Lower Mississippi-Gulf (LMG) Water Science Center created a digital dataset of the potentiometric surfaces of the Sparta Aquifer in Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee, which was developed from eight (USGS) reports. The potentiometric surfaces range in years from 1886 (predevelopment) to 2012 and cover north-central Louisiana with a selection of surfaces extending into the nearby states of Arkansas, Louisiana, Mississippi, Missouri, and Tennessee. Each surface was georeferenced to North American Datum 1983 and projected to USA Contiguous Albers Equal Conic projection. Once georeferenced, individual contour lines were digitized, and attributes were included for each potentiometric surface. Included for each report is a zipped folder containing the georeferenced surface and a shapefile that includes the digitized contour lines. The digital dataset of potentiometric surfaces provides the framework necessary to further investigate total volume of water and how it has changed through time within the Sparta aquifer. First release: April 2019; revised April 2021 (version 1.1). The previous version can be obtained by contacting the USGS Lower Mississippi-Gulf Water Science Center using the "Point of Contact" link on the landing page on ScienceBase. Reference: Collier, A.L., 2018, Withdrawals, in million gallons per day, by source type and water use category in the Parishes of Louisiana, 2014-2015: U.S. Geological Survey data release, https://doi.org/10.5066/F78051VM McGee, B.D., and Brantly, J.A., 2015, Potentiometric surface, 2012, and water-level differences, 2005-12, of the Sparta Aquifer in north-central Louisiana: U.S. Geological Survey Scientific Investigations Map 3313, 2 sheets, https://dx.doi.org/10.3133/sim3313 Potentiometric maps included in this dataset: Brantly, J.A., Seanor, R.C., McCoy, K.L., 2002, Hydrogeology and potentiometric surface of the Sparta aquifer in northern Louisiana, October 1996: U.S. Geological Survey Water-Resources Investigations Report 02-4053, 3 sheets, https://doi.org/10.3133/wri024053 McGee, B.D., and Brantly, J.A., 2015, Potentiometric surface, 2012, and water-level differences, 2005-12, of the Sparta Aquifer in north-central Louisiana: U.S. Geological Survey Scientific Investigations Map 3313, 2 sheets, https://dx.doi.org/10.3133/sim3313 Reed, J. E., 1972, Analog simulation of water-level declines in the Sparta sand, Mississippi embayment: U.S. Geological Survey Hydrologic Atlas 434, 1 sheet, https://doi.org/10.3133/ha434 Ryals, G. N., 1980, Potentiometric maps of the Sparta Sand, northern Louisiana and southern Arkansas, 1900, 1965, 1975, and 1980: U.S. Geological Survey Open-File Report 80-1180, 1 sheet, https://doi.org/10.3133/ofr801180 Schrader, T. P., 2004, Status of water levels and selected water-quality conditions in the Sparta-Memphis aquifer in Arkansas and the Sparta aquifer in Louisiana, spring-summer 2001: U.S. Geological Survey Scientific Investigations Report, 3 sheets, https://doi.org/10.3133/sir20045055 Schrader, T.P., 2007, Potentiometric surface in the Sparta-Memphis aquifer of the Mississippi Embayment, spring 2007: U.S. Geological Survey Scientific Investigations Map 3014, 1 sheet, https://doi.org/10.3133/sim3014 Schrader, T. P., and Jones, J. S. (2007). Status of Water Levels and Selected Water-Quality Conditions in the Sparta-Memphis Aquifer in Arkansas and the Status of Water Levels in the Sparta Aquifer in Louisiana, Spring 2005: U.S. Geological Survey Scientific Investigations Report 2007-5029, 2 sheets, https://doi.org/10.3133/sir20075029 Smoot, C. W., and Seanor, R. C. (1991). Louisiana ground-water map no. 3: Potentiometric surface, 1989, and water-level changes, 1980-89, of the Sparta aquifer in north-central Louisiana: U.S. Geological Survey Water-Resources Investigations Report 90-4183, 2 sheets, https://doi.org/10.3133/wri904183