NEW RESULTS FROM A DEEP/SHALLOW PIEZOMETER NEST IN THE PENNSYLVANIAN INGLEFIELD SANDSTONE AQUIFER, SOUTHWESTERN INDIANA

A nest of deep and shallow piezometers (ground-water monitoring wells) was installed at the site of a new science-education building for the University of Southern Indiana in November 2001. During installation, bedrock cores were recovered from depths of 30.5 to 33.5 meters (100 – 110 feet) and 17 to 18.3 meters (56 to 60 feet). Core depths correspond to the screen locations of each piezometer. Drilling for the deep piezometer encountered the West Franklin Limestone at an approximate depth of 32.6 meters (107 feet). The overlying Inglefield Sandstone Member of the Patoka Formation is well-bedded with organic-rich horizons and a pronounced limestone-pebble conglomerate at its base. Screened intervals of the piezometers isolate shallow and deep saturated zones within the Inglefield Sandstone. The Inglefield Sandstone is a primary source for local domestic water supplies. Initial geochemical signatures from sampled water differentiate deep ground water from shallow ground water. Deep ground water at this locality is more mineralized than shallow ground water, displaying significantly higher values of specific conductance. Preliminary physical hydrogeological data indicate the presence of a strong vertically-downward hydraulic gradient within the Inglefield Sandstone. Continuing work includes a more detailed analysis of stratigraphic characteristics of this aquifer system, and more thorough analyses of physical and chemical hydrogeologic characteristics of this ground-water system.