An Interstate Highway of Water
Beneath the forests of Florida's Panhandle lies the longest underwater cave system in the United States. The Wakulla-Leon Sinks Cave System is a subterranean network of conduits and passages that stretches for more than 45 miles (72 kilometers) through the limestone bedrock of the Woodville Karst Plain. This vast system is a primary drainage basin for the Floridan Aquifer, one of the world's most productive aquifers. The main outlet for this incredible volume of water is Wakulla Springs, a first-magnitude spring that discharges an average of 200-300 million gallons (760,000–1,140,000 cubic meters) of water daily. On April 11, 1973, a peak flow was measured at 1.2 billion gallons per day.
The passages, carved by the slightly acidic rainwater dissolving the limestone, vary dramatically in size. Some are small enough for only a single diver to pass, while others are enormous chambers up to 100 feet wide and 70 feet high. Much of this system lies at an average depth of 275-300 feet below the surface. For decades, explorers believed the major cave systems of Leon Sinks and Wakulla Springs were connected. The confirmation came on December 15, 2007, when divers from the Woodville Karst Plain Project (WKPP) completed a traverse between Turner Sink and the main Wakulla Springs conduit, officially linking the two and creating the nation's longest underwater cave. Subsequent explorations continue to expand the known map, with another major connection to Chip's Hole confirmed in January 2023.