Investigation of the Hydrogeology of the Memphis Light, Gas, and Water Shaw Wellfield, Shelby County, Tennessee

The dynamics of sources and pathways of recharged water to the semi-confined Memphis and confined Fort Pillow aquifers were investigated to assess the sustainability and vulnerability of groundwater resources within the Shaw wellfield located in Memphis, Tennessee. Geochemical and environmental tracer data were used to study compartmentalized groundwater flow in the Memphis and Fort Pillow aquifers, assess the vulnerability of the Memphis aquifer to modern water recharge (\u3c60 years old), and to determine the source(s) and pathways of modern water recharge. Hydrologic tracer data indicate wells in the northwest corner of Shaw wellfield are vulnerable to modern water recharge, with wells 704 and 708 having up to 17% component of modern water. Isotopic data show the Fort Pillow aquifer water has an older and chemically distinct source from the Memphis aquifer, which supports groundwater flow to the Fort Pillow aquifer is compartmentalized from that in the Memphis aquifer