UNSATURATED ZONE HYDROLOGY OF THE EDNA'S DOME SHAFT COMPLEX OF THE MAMMOTH CAVE SYSTEM, KENTUCKY
Five dye injections were conducted during wet conditions in spring 2000. After testing for the absence of background contamination, 25 mL each of Rhodamine WT and fluorescein dyes were injected into two sinking surface streams (the Eastern and Western branches of an unnamed ephemeral stream) above the shaft area in February. The waters of six separate shafts (Hawkins's Spring, the "Water Clock", and Edna's, Nelson's, Einbigler's, and Cathedral Domes) were monitored with charcoal dye receptors, which were replaced and analyzed by elution and spectrofluorophotometry over the next 67 days. The five shafts closest to Edna's Dome were all positive for fluorescein within nine days, and no dye was detected at Cathedral Domes. No Rhodamine was detected, so larger amounts of were injected into the Eastern Branch in early and late March and were detected at three of the shafts, including the most distant at Cathedral Domes. A third dye, eosine, was injected in late March at different sinkpoint nearby and was detected within a week at a different trio of shafts with some overlap between the other traces.
Results show that the flow paths consist of steep, vertically bifurcating conduits between a single surface input and multiple shafts within the cave. These are also overlapping networks, in that a single shaft can receive flow from more than one surface input. While shafts are known to occur commonly in groups (complexes), the bifurcating flow identified here may provide an explanation for this clustering.