DIRECT SURFACE WATER RECHARGE TO CLEVERSBURG SINK CAVE, SOUTH CENTRAL PENNSYLVANIA

Cleversburg Sink Cave is located in the Great Valley of south-central Pennsylvania. Most of the 1000m cave is prone to relatively rapid flooding followed by long periods of inundation. Planimetric cave surveys from the 1950s show linear passages limited to a limestone ridge; the passages appear to terminate at a nearby surface stream. Recent vertically-controlled surveys, though incomplete, indicate that most of the cave system actually lies below the nearby Burd Run stream channel that originates on siliceous Blue Ridge rocks and flows 4km over colluvium-mantled carbonates to Cleversburg Sink. InSitu^® data loggers placed in the cave and stream for three years reveal the relationship between water level, specific conductivity, and temperature.

Water level change in Burd Run and in the cave show a simultaneous fluctuation in water level (up to 7m in the cave), and a variation in specific conductivity from +300 µS to <100 µS, the latter being characteristic of allogenic Burd Run waters. Four specific events reveal that a more rapid decline in cave water level is directly related to the drying of Burd Run, demonstrating the direct hydrologic connection to the cave’s groundwater. Although dye tracing in the cave has been postponed because of a nearby water supply well, regional traces suggest that water from Cleversburg may leave the Burd Run watershed and travel to Big Spring, 10 km away.