School Sink (Wayne's World) Cave System
The Wayne’s World Sink Cave System is a coastal cave system in Hudson, Florida. Located only 3,000 feet east of the Gulf of Mexico, the system is tidally influenced. The cave system contains a mixture of tannic freshwater and saltwater. Tunnels that are springs at high tide become siphons at low tide and vice versa. The system is home to a variety of fauna including cave-adapted crayfish, isopods, and amphipods, anemones, mussels, hydrobiid snails, hydroids, and a species of feather duster worm that is found only in this cave system.
The following report was prepared by Hydro-Geo Environmental Research, Inc. and used with their permission. Note that exploration since this report was completed has connected School Sink (Wayne’s World) with nearby Beacon Woods, and total surveyed passage is 24,130 feet for School Sink and an additional 11,430 in the Beacon Woods System as of October 2004. School Sink is the 19th longest underwater cave in the world and 6th in the United States. Garman, Hemphill, et al first mapped school Sink and an updated map is in progress by Bojar and Hemphill.
Science Report for Wayne’s World Cave System
Hydro-Geo Environmental Research, Inc.
Wayne’s World Sink is located in Hudson, Pasco County, Florida, on approximately 15 acres of undeveloped land. The Sink is approximately 1500 feet east of the head of Cow Creek (a saltwater, tidally influenced creek) and approximately 3000 feet east of the Gulf of Mexico. The land that includes the sink is dotted by numerous water filled sinks and depressions and one small spring run typical of a karst setting. The water in the sinks and depressions is tannic from the degradation of organic material that is typical in a wetland environment.
The immediate area surrounding the property containing the Sink is residential and has numerous saltwater and brackish canals connecting the residences to the Gulf. The canals probably have also served to dewater many wetland and marshy areas so that they could be developed. As has been typical for many coastal areas of Florida that were developed prior to environmental concerns, the dewatering has over time lowered the hydraulic head of the Floridan aquifer; thereby, increasing salt water intrusion into the aquifer.
Hydrogeology
Wayne’s World Sink has formed in the Suwannee Limestone, which is at or near land surface in the vicinity of the Sink. The water in the sink and the cave system is brackish with saltwater intruding into the system through a deep saltwater tunnel. The sink is tidally influenced with a direct connection to the Gulf as the high and low tides are of approximately the same magnitude and at approximately the same time as corresponding tides in the Gulf.
The cave passages within the Wayne’s World Cave System are complex:
- Typical passage is approximately 90 to 110 feet deep with thick reddish brown silt on the floor. Visibility is usually 2 to 5 feet due to tannic conditions. On occasion visibility may reach 20 to 30 feet. At depths shallower than 90 feet, the system is characterized as a spongework cave with porous walls that look like Swiss cheese. Below 90 feet, the limestone becomes dense and the system is an anastomatic cave, consisting of arrays of curvilinear tubes that commonly intersect forming closed loops.
- Part of the system is a siphon feeding Spring #822-241A behind Hudson Bowl. Flow to this Spring appears to be constant with discharge occurring at high tide. The survey of the cave shows that one passage that ends at a pile of breakdown is directly beneath some of the Spring vents. No accessible passage through the breakdown has been found. Thus no entry or exit is possible through the Spring. The discharge of this Spring has been estimated at 30 cubic feet per second at low tide (Florida Geological Survey, Report of Investigations No. 39). The land in the vicinity of the Sink can not supply recharge for this much flow, indicating some recharge from wetland areas to the east of U.S. Highway 19 (see Figure 1).
- The Deep (140 to 150 feet deep) Salt Tunnel separates two brackish water tunnels that appear to have different water sources. The Deep Salt Tunnel has a variable temperature from 73° Fahrenheit (F) in the winter to 79° F in the summer but it is always warmer than the surrounding brackish water tunnels. The Deep Salt Tunnel often has a milky appearance limiting visibility to 1 to 2 feet. The milky appearance is believed to be due to the presence of hydrogen sulfide. The brackish water tunnels separated by the Deep Salt Tunnel have had temperatures that frequently vary by 1° F, which may indicate separate water sources.
- The Beyond (the brackish water tunnel beyond the Deep Salt Tunnel) is usually a spring (a diver swims into flow when entering this tunnel). Flow has been observed mixing with saltwater from the Deep Salt Tunnel but no siphon lead carrying the brackish water beyond the intersection with the Deep Salt Tunnel has been discovered. The survey shows that the Beyond has been pushed to the vicinity of an office building at the corner of US 19 and Hudson Ave. Residents have informed the dive team that in the past a sinkhole opened in the vicinity of the office and was filled in by the County. When the sink was filled, flow at Hudson Spring at the west end of Hudson Avenue decreased dramatically. It is possible that the Beyond is pirating flow that once discharged to Hudson Spring. There are undoubtedly numerous unexplored leads in the Beyond. This estimation is based on the fact that most of the exploration in this area was performed in tannic water with 2 to 3 feet visibility.
- Tornado Alley is an area of high flow and rock breakdown, which survey data have shown to be located directly beneath Spring #822-241A. No passage through the breakdown or access to the surface have been discovered at this time. On top of the breakdown pile there are two impassable vents carrying water to the surface while some of the water flows passed the breakdown pile into a narrow bedding plane that remains impassable in spite of numerous attempts to negotiate it.
- Even though it was discovered in the Spring of 1996 over a year after exploration began, the Main Street Tunnel is believed to be the primary passage. Main Street has considerably less silt than other brackish water tunnels in the cave. It is a strong siphon toward the Gulf at low tide and a strong spring inland at high tide. Swimming toward the entrance to the Main Street Tunnel, the direction of flow can abruptly change from spring to siphon. This may be a groundwater divide created at low tide with some water flowing toward the Main Street Tunnel and some water flowing toward Spring #822-241A.
- The Main Street G Tunnel is one of numerous leads off the Main Street Tunnel. While the Main Street Tunnel generally trends to the southwest, the G Tunnel trends to the northeast. The G Tunnel is a spring and the water is less tannic and cooler than the rest of the system. The G Tunnel is heading under a section of canal northeast of the Sink that is usually clear and is fed by seven small spring vents. It is possible that continued exploration will lead to cave passage with clearer water.
The hydraulic complexities of the system are only beginning to be understood. Additional exploration and survey combined with water sampling for key components such as chloride, sulfide, and total dissolved solids may provide some clues to the sources of water in the system.