Various geologic, hydrologic, and geochemical methods were used to assess active ground‐water circulation in a brine‐filled, deep (> 50 m below land surface) aquitard underlying the Oak Ridge Reservation, Tennessee. In places, the brine which was presumed to be stagnant in the past, contains various contaminants. If ground‐water circulation is viable in the brine‐containing formations, then remediation or containment of the deep‐seated contaminants should be considered a high priority. Data used to determine this included (1) spatial and temporal pressures and hydraulic heads measured in the aquitard, (2) hydraulic parameters of the formations in question, (3) vertical temperature gradients, and (4) spatial and temporal chemical and isotopic composition of the saline ground water. Conclusions suggest that the saline water contained at depth is not isolated (in terms of recharge and discharge) from the overlying active and fresh‐water‐ (< 500 mg/1) bearing units. Consequently, influx of young water (and contamination) from land surface does occur. Potential discharge into the shallow aquifers was assumed where the hydraulic head of the saline water was higher than that in the shallow aquifers, accounting for temperature and salinity anomalies observed close to land surface. The confined water (and dissolved solutes) move along open conduits at relatively high velocity into adjacent, more permeable units.

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