Preliminary delineation and description of the regional aquifers of Tennessee -- Highland Rim aquifer system

The Highland Rim aquifer system in Tennessee is primarily composed of Mississippian carbonates and occurs west of the Valley and Ridge Province. It crops out in the Highland Rim and the Sequatchie Valley. It has been removed by erosion from the Central Basin. Groundwater in the Highland Rim aquifer system occurs primarily in secondary openings including solution openings, joints, and faults. The Chattanooga Shale is the lower confining layer for the Highland Rim aquifer system. Under the Cumberland plateau, this aquifer system is separated from the overlying Pennsylvanian formations by the Pennington Shale. The Highland Rim aquifer system is an important source of drinking water. It supplies most of the rural, domestic, and many public supplies of drinking water in the Highland Rim. Where there is a dynamic flow system, dissolved solids concentrations are less than 500 mg/L. However, isolated cells may exist where the groundwater has dissolved solids concentrations of more than 1 ,000 mg/L.