"PRELIMINARY RESULTS: ASSESSMENT OF MEMPHIS AQUIFER CONFINEMENT USING BOREHOLE DATA IN THE WEST TENNESSEE MEGASITE"

Previous analysis of available lithologic and geophysical borehole logs suggests the Memphis aquifer is only partially confined beneath the Megasite Authority of West Tennessee (MAWT) property in Haywood County. This study seeks to address the potential for a direct hydrologic connection from the ground surface to the Memphis aquifer at the MAWT to characterize conditions for wellhead protection. The MAWT is a 4,100-acre property that will be home to an electric vehicle assembly and battery manufacturing campus and supplier park. Seven high-capacity production wells, which are screened in the Memphis Sand, will supply water to the site’s industrial tenants. The Memphis Sand, which has been subdivided into several informal members in previous studies, comprises most of the Memphis aquifer. Detailed lithologic and stratigraphic observations were made during sonic drilling of six boreholes conducted at the site. Modern alluvium and Pleistocene loess comprise the surficial deposits encountered at and adjacent to the property. Surface deposits are disconformably underlain by the Eocene Claiborne Group strata, including the Cockfield Formation, Cook Mountain Formation, and the Memphis Sand. The Cook Mountain Formation, which acts as the main confining unit for the Memphis aquifer, is discontinuous at the site. Additionally, chemical weathering observed in the upper and middle Memphis Sand suggests recharge of modern, oxygen-rich water. These data suggest there is potential for recharge to the Memphis aquifer directly from the ground surface within or near the MAWT study area.