Georeferenced Maps of the Thickness of the Sparta Aquifer in MS, AR, and LA, 1961 to 1996

The Sparta aquifer is a primary source of groundwater in north-central Louisiana. In 2015, more than 60 million gallons per day were withdrawn from the Sparta aquifer, of which over 90 percent was used for public supply and industrial purposes (Collier, 2018).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 thickness of the Sparta Aquifer in Arkansas, Louisiana, and Mississippi, which was developed from two (USGS) reports. The thickness surfaces are from years of 1968 and 1996 that are a variety of thickness, piezometric, structure-contour, and altitude maps. 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 thickness 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 thickness surfaces provides the framework necessary to further investigate total volume of water and how it has changed through time within the Sparta aquifer. 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 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 Payne, J.N., 1968, Hydrologic significance of the lithofacies of the Sparta Sand in Arkansas, Louisiana, Mississippi, and Texas: U.S. Geological Survey Professional Paper 569-A, 17 p., https://doi.org/10.3133/pp569A