Exploration of the underwater caves of the Woodville Karst Plain, Northern Florida, USA

Abstract

During the past ten years, cave divers of the Woodville Karst Plain Project (WKPP) have been exploring the cave systems of the Big Bend area of northern Florida, USA. The exploration has been challenged by the depth and horizontal extent of the completely water filled cave passages. A majority of the passages are in excess of 65 mfw. To overcome these obstacles the WKPP has utilized mixed-gas technology, specially generated decompression tables, custom built long range propulsion vehicles, and specific team-oriented procedures and equipment standards to ensure maximum diver performance without compromised safety considerations. Single dives have extended past a range of 3 km penetration at depths averaging 86 mfw for up to 3 hour bottom times. In-water time, including bottom time and decompression, has increased beyond 10 hours. Through the divers efforts, over 22 km of passage have been successfully explored and mapped. These accomplishments have been attained in conjunction with specific hydrological, geological, and biological scientific research. The WKPP is providing previously unattainable scientific data necessary for further understanding of this unique environment.

1. Introduction

From the southern edge of the Tallahassee city limits, extending south to the Gulf of Mexico, lies a region known as the Woodville Karst Plain (WKP). The WKP, present in southern Leon, eastern Wakulla and western Jefferson Counties, is characterized by a layer of unconsolidated sands overlying a thick sequence of carbonate deposits (HENDRY & SPROUL, 1966). The karst plain extends under the Gulf of Mexico and has an area of over 700 square km. Geomorphically, this area is distinguished by the presence of sinkholes, karst windows, sinking streams and large springs. The WKP contains seven of Florida’s 27 first magnitude springs, including Wakulla Springs, Spring Creek, Indian Springs, and Shepard Springs (RUPERT & SPENCER, 1988). Most of the drainage is subsurface through large open conduits developed in the Floridan Aquifer. It is the principal member in regional groundwater flow to the south. The Upper Floridan has very high transmissivity rates due to the high permeability and porosity of the St. Marks and Suwannee Limestones. All underwater caves developed in the WKP are formed within these two geologic formations.

The WKP has long attracted cave divers, from original explorations in the 1950’s to the present. Although exploration has been undertaken continuously, progress had proceeded very slowly until the late 1980’s. Due to the depth and horizontal extent of the caves, exploration has been limited by technological, physiological, and organizational constraints. The WKPP has been instrumental in overcoming many of the problems which have impeded past exploration efforts. The unique history of the WKPP, its commitment to the pioneering of new techniques for deep cave exploration, the development of groundbreaking technologies, and its responsibility towards safety and equipment standards, set this team apart from all others. The WKPP has proved, through their previous accomplishments and current dedication, to be an organization unmatched in today’s sphere of modern diving exploration.

2. History

The WKPP grew out of the exploration of Sullivan Sink in 1985. The Sullivan divers began to adopt a standard philosophy toward equipment configuration and diving techniques (TURNER, 1991). In 1986, Bill Gavin and Bill Main, brought these emergent techniques together into a systematic configuration and philosophy termed “Hogarthian.” This would later become one of the principal factors setting the WKPP apart from other cave diving groups.

The Sullivan divers began to shift their attention to the downstream component of Sullivan Sink. This deep passage was thought by many to be connected to Emerald Sink, some 1000 m straight line distance on the surface to the southeast. There were many obstacles to overcome, the first being depth. Downstream, Sullivan was over 70 mfw deep and siphoning. The second obstacle was the horizontal distance of travel. The divers estimated it to be between 300 m to 1000m past the current limit of exploration. The Sullivan divers, including Gavin, Main, Parker Turner, and Lamar English, attempted the Sullivan-to-Emerald connection, with Bill McFaden acting as support diver and cartographer (TURNER, 1991). They used Cheryl Sink, a small sinkhole a little over 100 m upstream from Emerald, as the staging point for exploration upstream toward Sullivan.

Gavin developed new techniques and equipment, while Turner consulted decompression expert Dr. Bill Hamilton. The team began employing the use of special gas mixes of helium, nitrogen and oxygen termed “trimix.” In early 1988, after many dives from both Sullivan and Cheryl, the caves were connected to a total extent of 12.5 km, at the time the longest surveyed underwater cave in the world (TURNER, 1991). Overshadowing this accomplishment was the death of McFaden in Little Dismal Sink in May of 1988. Shocked by the loss, the Sullivan divers began to formulate a set of agreements regarding deep cave diving procedures.

On June 19, 1988 Gavin, Turner, Main, and English traversed from Sullivan to Cheryl Sink, breaking the world record held by the British at Kelds Heald, UK and John Zumrick at Promise Sink, USA (TURNER, 1991). Turner negotiated continued access to Leon Sinks by drafting a set of standards on mixed gas cave diving, and exploration and research of caves, in the US Forest Service geological area. Joining the original connection team were Sherwood Schile and Steve Irving. Both were well versed in the Sullivan techniques and had proven themselves in deep gas diving.

Unable to successfully utilize their affiliation with the National Association of Cave Diving (NACD) to seek funding, the Sullivan divers, through the efforts of Turner, applied for project status from the National Speleological Society (NSS). On October 24, 1990, Dr. Art Palmer welcomed the WKPP as an official project of the NSS (TURNER, 1991). The team began to grow with many new members, including George Irvine, Jarrod Jablonski, Steve Berman, Todd Kincaid, and Casey McKinley.

Exploration continued, with emphasis on Innisfree Sink. A keen interest developed about Indian Springs, as this could be the next site with a high potential to be connected to the Leon Sinks System. After development of decompression profiles and many months of planning, the first in a series of exploration dives was completed by Turner and Gavin on November 17, 1991. Tragically, Turner died when he and Gavin were trapped by a freak sand slide, which blocked access to the spring pool (GAVIN, 1991). Gavin, barely made it to the decompression bottles in time, having followed a line laid by Turner just before he had drowned, essentially leading him out.

Needless to say, this was a dreadful loss to the WKPP and cave diving community. The most ironic aspect of the accident was that none of the five basic rules of cave diving had been compromised. This condition of the accident was very unsettling to many. The possibility of completing a dive, abiding by all the rules, and yet being killed by some freak geologic event put the prospect of deep cave diving exploration in a precarious situation. To its credit, the WKPP forged ahead and continued with exploration, making major advances in downstream Innisfree Sink. Soon Darkwater Sink and Bulldugger Sink (later named Turner, in memorial) were connected to Innisfree Sink (IRVING, 1997).

Bill Gavin became acting Director of the project. The project continued to grow with the addition of several new members. Exploration continued as did the search for a sufficiently long range propulsion vehicle sufficiently robust for depths below 60 mfw. Gavin began to embark on this problem. After various improvements to the Tekna scooters the team was then using, he began developing new super scooters. These scooters had extended main compartments, which could accommodate several large batteries, and were of the proper volume to provide neutral buoyancy for prolonged excursions.

Gavin had secured limited access to Wakulla Springs and Sally Ward Spring. Each new series of dives yielded more and more passage. An emphasis was being made on connecting Big Dismal and Little Dismal Sinks to the Sullivan – Cheryl connection passage. Exploring leads from Cheryl Sink, at a passage named the Bitter End, proved very difficult. The penetration distance was almost 2500 m at a depth of 75 mfw. On one of the push dives during 1992, Sherwood Schile drowned, a victim of repeated entanglements and mistakes, and final panic in a restriction (IRVING, 1997).

In 1993, exploration focused at downstream Turner Sink. The Gavin super scooter prototypes were well tested, and their production, following minor modifications, was begun in earnest by Gavin and Irvine. Irvine instituted a condition that all components of the new super scooters were to be standardized, so that each were made identical, thus making repair and replacement more simple and less time consuming. At this time, English and Gavin began to limit their diving. In the Spring of 1994, George Irvine became Director, with the main exploration divers being Irving, Jablonski and McKinley, while Todd Kincaid, Brent Scarabin, Barry Miller and Rick Sankey rounded out the main diving team. There were many others who assisted on the surface and conducted in-water support.

Irvine and English, while in the Yucatan, pioneered another very important technique that would prove invaluable on later extended explorations. They began staging scooters, much like staged bottles to increase effective gas range. This extended the penetration distance per unit time and effectively insured redundant scooters in case of a failure. This was accomplished by towing the scooter behind the divers, using a long tow leash clipped to the back of each diver below the bottom of the twin tanks. With this technique in place, the limits of exploration were ready to be successfully pushed.

After extended delays due to inclement weather, namely tropical storms and hurricanes, the exploration efforts were severely hampered by water clarity. In the Spring of 1996, exploration commenced with major pushes in Wakulla and Big Dismal. On May 11, 1996, Irvine, Jablonski, and McKinley entered Big Dismal, and in a short time connected it to the Leon Sinks Cave System, closing the 220 m gap between lines separating the two systems (WISENBAKER, 1996). On August 4, 1996, the team of Irvine, Jablonski, and Scarabin, on a six-stage, double-scooter dive, extended the Wakulla “O” tunnel to 3040 m. The dive involved a 155 minute bottom time at depths between 80 – 90 mfw with a decompression time extending to 8.5 hours (IRVINE, 1996).

2. Recent accomplishments

The autumn of 1996 saw many new achievements by the WKPP. On November 30, 1996, Rick Sankey and Brent Scarabin prepared for a dive into Chip’s Hole. This cave was originally explored by Sheck Exley to an incredible distance of 3045 m. With Exley’s survey data indicating that the cave passage increasing in size at the end of the line, and the proximity of Chip’s Hole to the lower extent of the Leon Sinks system, Sankey and Scarabin constructed a plan to push the current length of the surveyed cave. With Barry Miller, Jesse Armantrout, Ken Sallot, and John Rose transporting extra bottles and scooters during several gear staging dives, Sankey and Scarabin were ready for the push dive.

The team of Sankey and Scarabin, with six stage bottles, three scooters, and redundant primary lights, penetrated the cave to a new world record of 4297 m from Cal’s Cave, a sinkhole some 270 m from the entrance of Chip’s Hole. This penetration beat the previous record set by Olivier Isler, thus making the total penetration of the dive 4567 m. This is the farthest penetration (4297 m), from a natural cave opening to the surface accomplished by cave divers (SANKEY, 1997). The bottom time was 300 minutes, with decompression extending this an additional 180 minutes (SANKEY, 1997).

During the later part of 1996 and the first few months of 1997, a new semi-closed circuit rebreather was tested, mainly by Irvine and Jablonski. The bulk of the test dives conducted were shallow and short duration, thus allowing added safety margins to work out any difficulties which might arise. Several excursions to 85 mfw and penetrations of close to 1000 m have been conducted to test the potential of the new machines. Several of the deep mix divers have been practicing with the rebreathers, and the upcoming season promises to be an exciting one with new achievements on the horizon.

Barry Miller, the team videographer, has been active the past few months producing a new video entitled “WKPP” for the NACD Workshop. This video gives a brief hydrogeologic overview of the WKP, a team history, and new video footage of Wakulla and Indian Springs. The video is narrated by Rick Sankey, and provides a great introduction to the WKPP and the WKP. The video has incredible footage of dive team operations, with some extraordinary shots of actual exploration dives. Working with Irvine and Jablonski on the new rebreathers, Miller is currently producing a video which focuses on the new semi-closed circuit technology, techniques, and equipment configuration.

Irvine has secured continuous access to all the major springs and sinks within the WKP. Through his unparalleled efforts and cooperative endeavors with state and federal agencies, Irvine has given the WKPP consistent access to all dive sites. Without his efforts, none of the accomplishments within the past three years would have been possible. The WKPP permits have been renewed through the year 2000, promising even larger accomplishments for the future.

Irvine has also been instrumental in standardizing support and exploration procedures, thus increasing the safety of all team members. With the initiation of these very strict operating procedures, there have been no significant life threatening injuries or fatalities. The safety record of the WKPP, since Irvine became director, has been exceptional. Without concerted team effort and support, this accident would have been fatal. In light of the earlier tragedies which had beset the team, Irvine and other team members have been relentless in striving for safety practices and procedures which ensure optimal diver awareness.

3. Scientific research support

The WKPP has become the eminent platform for scientific research within the WKP. Through the cooperation of five state agencies, four federal agencies, two major universities, and various local and county officials, the WKPP provides a unique facility for researchers. This platform allows the acquisition of samples and data, which has been unattainable in the past. With this cooperation, the WKPP is able to actively participate in ongoing research at the local and regional scale.

The exploration and mapping of the various underwater conduits of the WKP, has provided local officials and planners the best source of information needed to make informed decisions. These decisions include future road and highway construction, residential community construction, and corporate and industrial site evaluations. The WKPP has been working with the Apalachicola National Forest to conserve and protect its natural resources and is providing an environmental hydrogeologic information base to aid in the preservation of the St. Marks National Wildlife Refuge.

The WKPP is contributing information, previously obtained, to various university hydrogeologic investigations involving water quality analyses, isotopic water studies, and is providing a platform for new and continuing water conservation projects. Working with many leading researchers in the field, the WKPP is engaged in surface and groundwater interactions research, water tracing techniques in submerged karst, and microbiology of bacterial colonies existing within the underwater conduits of the WKP. The continuation of paleontologic investigations with various museums and state geologic agencies continues with the discovery and excavation of invertebrate and vertebrate fossil species.

4. Conclusions

The WKPP has been committed to the exploration of the underwater caves of the WKP. In doing so, the WKPP has forged ahead in the advancement of diving techniques and team-oriented standard operating procedures. A few original members have methodically designed an equipment configuration protocol termed “Doing it Right.” Other members have pioneered new technologies, that have made a large impact in the ability of the team to continue to push the envelope of exploration. With the recent long range extended exposures now being attempted, the WKPP is again moving ahead to overcome the new challenges of deep cave diving.

Throughout its history, the members of the WKPP have concentrated on the team concept, knowing that any real efforts to seriously explore the depth and length of the caves of the WKP could not be accomplished by any single person. To its credit, the WKPP has readily dispensed information concerning new diving techniques, decompression theory, equipment configuration, and the principles and standards for team-oriented operations. The WKPP has been instrumental in bringing to light many of the common misconceptions of cave diving exploration and has sought to educate the cave diving community. Through its efforts and collaborations with various state and federal agencies, major universities, and research scientists, the WKPP is providing a platform for extensive scientific investigation. This broad cooperation is aiding in the understanding of the unique environment of the Woodville Karst Plain and the conservation of its environmental resources.

References

GAVIN, BILL, 1991, Diving Accident at Indian Springs – November 17, 1991, NACD Journal, V. 23, n. 4, pp. 75 – 76.

HENDRY, C. W. & SPROUL, C. R., 1966, Geology and groundwater resources of Leon County, Florida: Florida Geological Survey Bulletin 47.

IRVINE, GEORGE, 1996, Woodville Karst Plain Project, personal communication.

IRVING, STEVE, 1997, Woodville Karst Plain Project, personal communication.

RUPERT, FRANK & SPENCER, STEVE, 1988, Geology of Wakulla County, Florida: Florida Geological Survey Bulletin 60.

SANKEY, RICK, 1997, Woodville Karst Plain Project, personal communication.

TURNER, PARKER, 1991, Woodville Karst Plain Project, unpublished manuscript.

WISENBAKER, MICHAEL, 1996, Woodville Karst Plain Project Update, NSS News, V. 54, n. 11, p. 303.