Exploration of Convict Springs

By Michael Poucher

Introduction

Convict Springs is located on the south side of the Suwannee River, northeast of Mayo, Florida at Jim Hollis's River Rendezvous. Jim Hollis offers camping, rooms, cabins, canoe rentals and a restaurant on the property. He also has a dive shop and does boat tours on the Suwannee and to Troy Springs. Unfortunately, cave-diving is not allowed in Convict Spring except by special permission.

History

Convict Spring was so-named because the State of Florida used the property to house chain gangs in the early 1900's. About 1968, a team of divers from the University of Florida explored the cave to 497 feet of penetration. Scheck Exley and Mary Ellen Eckhoff dove the cave in 1981 and mapped the first 93 feet of cave. They were stopped by a sand-filled, major restriction. It was a low, silty, dark cave and it didn't look very promising, so the cave sat until 1992. At that time, Bill Rennaker was teaching some cavern courses for Jim Hollis and he asked Jim if he could dive the spring. Bill is an accomplished sidemount diver and knew his style of diving opened up many previously "walled out" caves to new exploration. Jim just pointed out his "No Cave Diving Allowed" sign next to the spring and that was that. However, a short time later he gave Bill permission to enter the spring.

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New Exploration

On the first dive, Bill Rennaker and John Moseley spent over an hour underwater and explored the cave over 500 feet to where the Hangin' Tree is on the map. This feature is an old tree that fell through, or broke through a hole in the ceiling of the cave. Jim, who had been very concerned when they were gone so long, was delighted when they surfaced and he found out his spring was still going! On the next dive, Bill and Dell Moats extended the cave another 500 feet to a large room with a small sand restriction in the floor. Bill took the reel at this point and plowed through the restriction. After 75 long feet of very tight, sand filled passage the cave opened up again into a small canyon. Bill then went back and signaled Dell that the cave continued and they laid line up to where the cave splits into two passages. Later, John Moseley came back and continued exploration in the northern passage to a total penetration of 1530 feet. The cave ended in a small passage and a clay/silt restriction and seemed to be pinching off. Bill Rennaker and Bill Dooley did an additional eight dives to shoot the Convict Springs video and then diving stopped for a while.

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The Survey

In December of 1996, I asked Jim Hollis if I could dive the cave and begin mapping it. Bill Rennaker had surveyed the first 1000 feet and I was going in to sketch the details and pick up the last 500 feet. After seeing the video and talking to Bill about it, I expected a challenging dive and wasn't disappointed. The series of sand restrictions at the very beginning left me sweating in a dry suit from the exertion. I didn't even want to think about what the passage looked like behind me from all the silt I stirred up! The cave opened up some, but visibility never got much better than ten feet or so. Convict has one of the highest concentrations of nitrates in the state and visibility never seems to get more than twenty feet and is typically five to ten feet. I did several dives in Convict over the next few months and surveyed to the end of the line and to the end of several dead-end tunnels in the back. I also pushed all the leads in the front in an effort to find more passage. Everything dead-ended in sand choked passages though.

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Another Discovery!

Finally, on a clean-up dive to double check the map, I noticed some cross-flow and found a small canyon passage heading southwest. I tied off a reel and headed down the passage. The cave would go for fifty or sixty feet and then there would be a restriction. Each time I thought it was going to end, but I would squeeze through and it would open up again. Five hundred feet of line was laid that day and the passage ended in a split with clay silt restrictions blocking both sides and a total penetration of 1615 feet. Further exploration has only gone another 100 feet and the cave seems to pinch off in sand restrictions. Depth at this point is only 10-15 feet.

In subsequent dives, I've noted that the two ends of the lines are hydrologically connected even if not physically capable of being connected. I was pushing some of the leads on the new, south leg, stirring up quite a bit of silt in the process. I came out and went down the north leg and managed to push another hundred feet or so. The passage was getting very small, but I could see my silt cloud coming at me from the other tunnel. I tied off and got on out of there and I haven't been back.

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Nitrate Levels

As I mentioned earlier, Convict has one of the highest nitrate concentrations in the state. This results in a lot of bacteria growth in the cave. Brownish-red bacteria balls can be observed in the water and collect in some areas in the cave. Bacteria colonies also flourish in many of the alcoves off the main passage. I have also observed a basket-like growth on the line that appears to act like a net to catch food? I don't know what these are ands haven't talked to anyone that does, but it is an interesting feature. The cave also boasts crayfish and isopods in many areas as well as the usual catfish.

For now, exploration is done in Convict Spring. The use of sidemounts allowed the discovery of 2054 feet of cave in a spring previously thought to be insignificant. It's a very challenging dive due to the large number of restrictions, low visibility and numerous line traps and sidemounts are a must if you plan to go beyond 93 feet in the cave. However, the shallow depths (36 foot maximum) allow for long bottom times with no decompression and plenty of time for exploring.

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