The United States Geological Survey (USGS) has been a principal source of data and modeling software used in investigations of the Sparta Aquifer in southern Arkansas and northern Louisiana. USGS works with DNR, the Department of Transportation and Development (LDOTD), the Capital Area Groundwater Conservation District Commission, Union County (Arkansas) Water Conservation Board, the Sparta Commission, and others.
Studies of Regional Geohydrologic Characteristics
Geohydrologic characteristics of the Sparta Aquifer in southern Arkansas and northern Louisiana have been reported by, among others, Payne (1968), Hosman (1968, 1982), Broom et al (1984), Petersen et al (1985), Williamson et al (1990), Arthur and Taylor (1990, 1998), Fitzpatrick et al (1990), Brantly et al (1996), and Joseph (1998-2000). The reports by Payne, by Hosman, by Joseph, and by Brantly et al include potentiometric maps. Groundwater resources in specific areas of the Sparta region have been described by Sanford (1973-Morehouse, Ruston), Ryals (1982-Arcadia, Minden), and Trudeau and Buono (1985-West Monroe). References are provided by Brantly et al (3) and McKee and Clark (9). In 2002, Tomaszewski, Lovelace, and Ensminer published potentiometric maps constructed from USGS Sparta monitoring well water level data. (Ref. 15 and Figure 20)
Regional Ground-water Models as key water management tools
Water managers and users have been concerned about the ability of the Sparta aquifer to supply water for the long term in view of hydraulic head (well water level) decline greater than 1 foot per year for many years in many areas and hydraulic heads now below the top of the Sparta Sand in some areas. (8, 9)
In response to these concerns, in 1985, the USGS, with the Arkansas Soil and Water Conservation Commission (ASWCC) and the Louisiana Department of Transportation and Development began a project to study the hydrogeologic characteristics of the Sparta aquifer and evaluate the regional effects of increased pumpage. The primary product was a study using groundwater flow model MODFLOW88 software to simulate hydraulic heads in central and south Arkansas and north Louisiana from 1889 to 1985. (Fitzpatrick and others, 1990; McWreath and others, 1991; Kilpatrick, 1992) The researchers updated pumping data and predicted pumping scenarios on hydraulic heads in southern Arkansas from 1990-2019. Hays et al (1998) updated pumping data again and tested scenarios in south Arkansas and northern Louisiana, from 1998 to 2027. These studies are listed under Reference 27: 'Sparta Louisiana-south Arkansas Groundwater Models'.
In 2001, Meyer, Meyer, LeCroix, Hixson, with others, in a study for the Sparta Groundwater Conservation District Commission using MODFLOW software, optimized withdrawal rates to determine Sparta sustainable yields and to predict effects of different scenarios on hydraulic heads in Sparta wells in Louisiana from 2000 to 2025. (2)
In 2000 to 2002, USGS, ASWCC, and the U.S. Army Corps of Engineers worked cooperatively to modify and recalibrate the models of Fitzpatrick, McWreath and others for the purpose of evaluating potential pumping scenarios and optimizing withdrawal rates to determine sustainable yield for the Sparta aquifer in southern Arkansas and northern Louisiana. (8, 9) This is part of a continuing project to develop, maintain, and utilize numerical ground-water flow models as a water management tool.