The Ginnie Spring basin is a large, bowl-shaped depression measuring over 100 feet across and 15 feet deep. A 150-foot long run connects the basin to the nearby Santa Fe River. The chief attraction here is the Ginnie Cavern, whose wide, open entrance can be found at the bottom of the basin.
Ginnie Cavern is among the handful of sites that experts consider sufficiently safe to allow exploration by divers who lack formal cavern or cave diver training.
Certified divers of all experience levels may take lights into the water with them at Ginnie Spring and use these lights to explore the underwater cavern. The cavern’s upper room is illuminated by light from the entrance. Looking back toward the entrance from this room provides a breathtaking view. Like most of the cavern, the upper room’s walls are composed of an extremely light and highly reflective limestone, which adds to its natural beauty.
Moving to the back of the upper room, divers pass through a large opening into the amphitheater-sized area called the “Ballroom.” Although surface light is clearly visible from most places within the Ballroom, divers will want to carry dive lights to see everything there is to see.
The Ballroom provides divers with the opportunity to examine many of the unusual geologic formations that are unique to the Floridan Aquifer. The Ballroom’s ceiling contains an excellent example of spongework–a gigantic, limestone swiss cheese. Midway between floor and ceiling, divers will find evidence of a bedding plane–a distinctive horizontal crack that is crucial to the movement of underground water. At the northwest corner of the Ballroom is a beautifully carved phreatic tube–a perfect example of the most common form of underwater cave formation. Nearby, a larger bedding-plane formation collects air in mercury-like pockets on the ceiling.
At the very back of the Ballroom (a maximum depth of 50 feet), is a large, welded grate. This grate prevents divers from entering the dangerous, silty and maze-like cave system that lies beyond. Nevertheless, most divers enjoy pulling themselves up to the grate, so that they can experience the “in-your-face” force of the 35 million gallons of water a day that pass through the opening. A large-diameter, heavy duty guideline runs from the back of the Ballroom to the cavern entrance. This helps ensure there is never any doubt as to which way is out.
