Natural Bridge – St. Marks River Rise Exploration

Natural Bridge – St. Marks River Rise Exploration


Update by Chris Werner

Summer 2006

As conditions in the Woodville Karst Plain began to clear in early January 2006, a reconnaissance dive by Chris Werner and Todd Kincaid into the St. Marks River Rise revealed that conditions at even this most tannic of springs was improving. The dive was part of an initiative to place tubing for the City of Tallahassee Southeast Spray Field tracer test in order to effectively sample for dye from the surface. During the dive, visibility was approximately 10 ft, the best seen in a close to a decade. Field personnel would be checking the River Rise twice weekly throughout the year, allowing careful documentation of the visibility for the better part of the Spring and Summer.

As conditions improved, Chris Werner, Scott Cox and Jim Miller made initial exploration dives on May 5 and June 3, 2006. Conditions were between 5 and 10 ft of visibility, with strong flow. Though there were reports of exploration previously, no line was found in the cavern or cave. The initial exploration led to the discovery of two large phreatic conduits leading to the northeast, surfacing on two different sides of a large nearby sinkhole. The teamed laid a little over 1000 ft of line in the two outings.

In conjunction with these dives, the landowners of the adjacent parcels contacted Chris Werner about conducting an assessment of the hydrogeologic importance of the Natural Bridge – St. Marks River Rise area. In association with Hazlett-Kincaid Inc., the WKPP was permitted to explore, survey and map the underwater caves on all adjoining parcels of land, the data and finding to be incorporated into a final report for the landowners. The property has approximately 15 sinkholes with its northern terminus being the St. Marks River Sink approximately 1.3 km straight-line distance north from the River Rise.

Armed with the above agreement, knowledge of the potential for large phreatic cave and the fact that the initial exploration was relatively shallow, approximately 110 ft at its deepest depth, the team of Chris Werner and Scott Cox returned on June 9, 2006 to push the lead in the nearby sinkhole. The team laid an additional 850 ft of line in very tough conditions, with less than 5 ft of visibility. As Cox remarked jokingly, “The visibility was approximately 4 1/2 to 5 ft, but no more.” The team had found another large phreatic passage trending north and connected it with a surface run to the north.

On June 11, 2006, Werner and Cox returned to explore a surface boil on the newly connected surface run. The team entered a large phreatic tube at approximately 80 ft depth. With Werner laying the line and scootering on the left wall, the team got itself into a small canyon like passage with limited flow. Werner surveyed out while Cox set down arrows and placed the line to avoid traps. Once back in the basin, the team recalculated gas and decided to go back to where they had lost the flow. Werner tied in and made a bee-line for the opposite side of the room, there the visibility improved to 20 ft. Soon the reel was empty, but luckily Cox had another reel tucked away. The team tied in the other reel and Werner proceeded into a spring tunnel, up over a small breakdown mound and then straight down for 30 ft into a spring tunnel measuring 8 ft by 8 ft in cross-section with an average depth of 105 ft. The flow was like a fire hose, the team made its way along the passage for an additional 500 ft and tied off on a nice wrap. The team called the dive on gas, Werner surveyed out and then they proceeded with their decompression in the basin. High-fives were given once the team reached the surface as the mood was all smiles and congratulations.

Unfortunately, the good conditions would not last. On June 17, Werner and Cox returned to find that rain in the area had affected much of the river dominated passages. Visibility was back down to below 5 ft. The team proceeded to continue exploration in the spring tunnel found the prior week. With flow still raging, they managed to add 500 ft of line before encountering a tight restriction. They then proceeded to the far northern reach of the run following a short lunch and connected another four sinkholes in a stretch of the river that was dominated by clear spring flow.

The following weekend, on June 25, 2006, Werner and Pina Porceddu laid approximately 600 ft of line connecting another two sinks and cleaned up some survey left from the previous weekend. On July 1 and 2, 2006, the team of Werner, Porceddu and John Rose laid over 1200 ft of line connecting another four sinkholes near the northern edge of the property. Conditions had improved to nearly 20 ft of visibility, but a sticking compass slowed the survey. The long weekend provided an opportunity to obtain water samples for analysis and resurvey some stretches of line, this time with a new compass.

On July 8, 2006, Werner and Porceddu connected another two sinks, putting in over 700 ft of line. They were joined on June 9, 2006 by Derek Bennett. The three-person team laid an additional 750 ft of line and connected another two sinks. They team took time to resurvey a few exploration lines and search for leads in a newly discovered spring tunnel. Bennett joked to Werner following the dive, “The visibility was much less than 15 ft, you said the visibility was good, but you sure have a way of sniffing out where the passage was headed.” Everyone laughed as Werner replied, “15 feet is good visibility here!”

On July 15, 2006, the team of Werner and Rose entered the blackest sinks at the northern end of the property. An attempt was made to connect to the St. Marks Sink as an extended period of drought had allowed water levels to drop and flow from the river to diminish significantly. Werner tied in on a cypress knee, and with less than 3 ft of visibility, laid 250 ft of line emerging at the St. Marks Sink. Rose surveyed behind him, both surfacing in the some of the most polluted waters the two veterans had ever seen. Both were careful to avoid the fishing line, floating garbage and multitude of snakes.

Following a short surface interval, the team started into the other black sink. As they entered, Werner stayed on the left side, knowing that the right side of the passage will likely lead to the St. Marks Sink again. Instead of being very dark, the left side of the passage had visibility topping out at over 30-40 ft, the best seen thus far during the entire exploration. After some route finding in a few large rooms, Werner came across a massive 25 ft x 25 ft going tunnel headed north. Followed by Rose surveying, the team dumped 700 ft of line on a single stage at an average depth of 110 ft, calling the dive on gas. They were joined by Derek Bennett on July 16, 2006. Derek shot video on the dive as the team laid an additional 1200 ft of line. The northwestward trending tunnel was wide open at the end of the line, with a size of approximately 15 ft high and 30 ft wide and phreatic in cross-section.

In eight limited outings and while working in severely limited visibility for the majority of the dives, the WKPP explored more than two miles of new cave passage and connected more than 13 surface sinkholes and springs. The large passage headed north from the area holds the potential for extended exploration and mapping.


Turner Sink Gallery, July 1, 2006

Turner Sink, July 1, 2006

WKPP Update: Turner Sink, July 1, 2006


Update by Casey McKinlay

Early June efforts produced impressive results in both Turner Sink and Wakulla Springs but the summer rains and shifting weather pattern were beginning to have an impact on visibility in the cave systems. Wakulla visibility on June 10 was 60ft in the basin and 30ft beyond the 6,500ft depot. Wakulla visibility in late June had dropped to 50ft in the basin and I estimated visibility in the back to be 20ft or less making further exploration potentially less productive until conditions improved. Strangely enough the Leon Sinks system remained clear with Turner Sink visibility as good or better than the June 3 outing with moderate flow. Jarrod and I received the field report while attending the LA Scuba Show and decided Turner was the most logical choice with the best odds for success. Given the success of the last outing, the amazing cave passageway and the fact that Turner exploration promised huge going passage made the decision even easier. A late Saturday night flight back and 5 days to prepare would once again put everyone to the test but with visibility decreasing and the window of opportunity closing, we were anxious to take advantage of this opportunity. A quick call to Mark Messersmith and Todd Leonard kicked off another planning session for the trip “Downtown.”

June 30: Setup

(Bognar, Mudry, Canty)
Setup logistics were similar to the last outing on June 3. We decided to arrive earlier on Friday to get all the equipment prepped and staged for an early Saturday departure. Three setup divers made quick work of the deco gas placements at 120ft, 70ft and 20ft in addition to the harnesses and deco accessories placed at 40ft on the trough. Once the deco equipment was staged the setup team began placing the scooters and drive bottles for the RB80 setup and exploration teams. 12 scooters and 16 drive bottles were successfully delivered to the staging location inside the cave for the early Saturday departure. The basin would have 10 hours to clear out before the second downstream assault.

While preparing the exploration and support plan, it became clear that we would be stretching ourselves both in terms of the exploration and decompression. The previous exploration to 10,500ft required 120 minutes to add 6,000ft, total bottom time of 210 minutes and 10 hours of decompression. Attempting another 6,000ft exploration would require at least 6 hours downtown and 13 hours of decompression. 20 hours at Turner would be markedly different than 20 hours at Wakulla. The decompression logistics were uncomfortable to say the least with no option in place to switch to decompression RB80’s or get your head out of the water until 40ft. We expected the scrubbers to start breaking through around 12 hours but felt we could push them to 15 before going to open circuit. Food and hydration would also be an issue with a 20 hour exposure. Then again, this was Turner Sink and the tradeoff would be exploring the most incredible cave in the WKP with the hammer down.

July 1: Setup

(Garland, Messersmith)
Objective – deliver 2 scooters, 4 safeties and 4 drives to the first downstream stage drop. Using Halcyon RB80’s, the team made quick work of the assignment and delivered the goods to 5,500ft. Total bottom time was 90 minutes followed by a typical Wakulla decompression. They also caught a glimpse of the impressive cave passageway beyond 4,500ft. Jarrod and I discussed the pros and cons of placing a setup team in the water at Turner. The cons were mostly the difficulty imposed by same day diving logistics (excess equipment etc) and making sure the setup team did not blitz the cave system or encounter problems that might impact the exploration plan. The pros on the other hand could not be ignored because the dive would require more equipment than could be reasonably transported into the cave by the exploration team. We were prepared to suffer with excess equipment on the exit but anything to ease the pain on the in going ride would help tremendously. Mark and Mark had proven themselves capable, team players with several impressive dives at Wakulla and Chip’s Hole. The time had come to fully leverage our available resources.

(Jablonski, McKinlay)
Objective – travel downstream approximately 10,500ft and begin exploration. We planned to include Mini-Mee on the dive for video but discovered a cracked cover for the LED power indicator while assembling the unit on Saturday morning. Fortunately the problem was identified prior to putting the unit in the water which saved an HD camera and potential problems transporting a partially flooded scooter. We decided to go with 4 scooters each, 1 safety scooter, 4 primary drives each and a total of 4 safety drives. Mark and Mark would deliver a portion of the gear on the setup. Jarrod and I would depart the 190 drop with 2 drives each, Jarrod towing 2 scooters and me towing 3 scooters. Mark and Mark would have a 45 minute head start and an enjoyable ride out with minimal gear. Everything was falling into place as we pushed through the restriction and geared up at the rock. Visibility was as good if not better than the June 3 outing with moderate flow as we cleared the silt cloud and began the 1,000ft journey to the 190 drop. No broken blades, no hassles, 4 full reels and no video obligations. This run would be a fast and loose 2-man operation with the emphasis on exploring as much cave as possible to close the gap toward Wakulla. It felt like the old days except for the extra scooters, bottles and support but then again, we would need all of the above to get the job done.

We made quick work of the drive switch at 190 and motored downstream. We could tell there was a team running in front due to the particulate in the water but the lack of gear at this stage of the dive made the trip enjoyable. We rounded the 90 degree right turn at 4,000ft and passed Mark and Mark. A quick “all good” signal confirmed the goods had been delivered and were waiting at the drop. We passed the tie-in point from the June 3 dive and motored another 1,000ft to find the gear clipped off on the left wall almost 25 feet above the floor. The clock was running at 40 minutes. A quick switch to drive #2 and scooter #2 and we were off again with extra gear in tow. Amazing cave was before us as we motored another 50 minutes to 10,500ft. We arrived at 10,500ft and began to shuffle gear. Jarrod and I both dropped safety drives and full drives. We decided to keep the current drive plugged in given the small amount of gas used. This gave us 1 full safety drive and 1 reasonably full drive at 5,500ft, 1 full safety drive and 1 full drive at 10,500ft plus 2 drives to explore. Scooters #1 and #2 had plenty of burn to handle the exit from 10,500ft. Jarrod switched to a fresh scooter with a spare in tow and I switched to a fresh scooter with 2 spares in tow. This would be more than enough, or so it seemed.

Jarrod tied in as I pulled the pin on my survey scooter and patiently waited for the shot as he flew out into the void. I had to hold the rock outcropping because the tunnel narrowed at that point and the flow was pulling me downstream and away from the station. After a moment or two the tunnel took shape and we were off and running. The tunnel dimensions remained huge at 50ftx50ft and the depth stayed in the 270-280ft range. It shallowed up to 250-260ft for a short segment but dropped back deep again. The tunnel changed direction more often compared to the previous exploration as we entered and exited more rooms along the way. In several sections both Jarrod and I noticed pockets of blue water indicating a possible ground water tunnel but there was no time to investigate anything other than the massive conduit in front of us. At 160 minutes we entered an extremely large room and the tunnel shallowed up to 230ft. Jarrod paused, assessed the options and motored ahead as the tunnel narrowed and dropped down to the right. The tunnel zigzagged and we entered an extremely small passageway. We both knew that this was not the way on as I paused, inflated my wing and waited patiently on the ceiling for Jarrod to turn and tie off. Floor to ceiling clearance was 6ft, the tunnel was 10ft wide, depth was 298ft and we were 14,000ft downstream. Here we were in some rabbit hole with 5 scooters and 4 stages having a seemingly rationale discussion as to how we managed to lose Leon Sinks. My first thought was it was not possible to lose a tunnel that large with that much water moving through it. I did not want to come back and tell the team that Leon Sinks was finished and we were unsure whether it continued towards Wakulla. Jarrod shared the same outlook and remained committed to finding the way on before we turned back. We backed up, T’d in at the next junction, went through a duckunder and into another large room that quickly shut down. While Jarrod tied off again I decided to back up into the beginning of the main room and take a good look. I floated up to a shallower depth and looked up, behind, left and finally right. There was a large hill to the right covered with black silt. The walls from the floor to the ceiling were also solid black giving the illusion of a dead end. I motored up over the hill and took a look around the corner to the left. It began to open up and I caught a glimpse of some white limestone mixed in with the black as the tunnel took shape. I turned and motored back to the big room as Jarrod met me in the middle with reel in hand. Correctly assuming I shared the same resolve, Jarrod T’d in, I dropped an arrow on the line and we were off and running again. The tunnel blew wide open, dropped deep again and continued its trend south-southeast.

The clock was ticking at this point and the detour had cost us 20 minutes but we were committed to finishing the job. I caught up to Jarrod at the next station and he signaled that it was time to switch to a fresh drive. We switched, dropped the spent drives and motored further downstream. The tunnel at this point was changing at every turn but remained large. There were several sections where the tunnel narrowed down to 25ftx25ft borehole conduit and the water velocity increased significantly. As we neared the turning point, the tunnel split and came back together like a double barrel shotgun, took a 90 degree turn to the right and dropped again to 285ft. As Jarrod prepared the wrap on the wall he signaled me for an ok and I confirmed. I glanced at what had to be a few hundred feet left on the magnum reel and said “finish it off”. We motored on as the floor dropped away and Jarrod emptied the reel. We both searched for a good tie-off but there were few options aside from a large rock on the floor. Jarrod dropped down and completed the tie-off as I packed up the notebook, switched to a fresh scooter and pulled the big arrow from my right pocket. We shook hands, placed the arrow and silently agreed it was way past our turn time. 300-360 minutes total was not going to happen as we motored back to pickup the spent stages and head for the door. Bottom time was 217 minutes and we had 3 miles to go against a howling flow. At this point, propulsion was everything.

The 55 minute return trip to 10,500ft was reasonably quick and uneventful but then again we did not have that much equipment in tow. We switched drives and scooters in addition to taking a few minutes for a drink and snack break. We clipped off the additional scooter and bottles and motored upstream to 5,500ft. I had purposely positioned fast scooters as the final pair for the ride to the door with the 10,500 to 5,500ft scooter being extremely fast. At this point the additional gear began to slow us down. Jarrod had 3 scooters in tow and 4 drives and I the same less 1 scooter. The 5,000ft ride took 70 minutes and we both knew from 5,500ft to the 190 drop would be worse as we picked up another scooter and 2 more drives each. The final 4,500ft took 80 minutes and with more than 5 hours already on the clock it was starting to take a toll on both of us. We considered dropping equipment along the way and scheduling a cleanup dive but 4,500ft did not seem like that far to go. The floor, covered with black silt, did not appear to be moving below us in some spots as we averaged 56ft per minute; we were forced to kick through the narrow sections. Turner was trying to break us but we rounded the final corner and caught a glimpse of the 190 bottles suspended center conduit. What a sight as I checked my watch; 390 minutes. The support guys would need to settle in for a long evening in the woods. We plugged in our 190 bottles and held onto the rock as the flow tried to pull us back in.



The 210 minute dive on June 3 had provided us with critical information regarding the decompression logistics. We knew 390 minutes would require a great deal of patience, faith in the support team and confidence in each other that we were prepared to handle almost any situation on our own. We began the ascent from 190 and met up with the first support team at 140ft as they confiscated spent gear, confirmed the score (5,000ft added) and snapped a few images. As they departed for the sink it began to settle in that this would not be a 210 minute decompression. We continued the ascent to 120ft where we switched gasses and pushed the stop to maximize the benefit.

Unlike Wakulla where there is a large sand slope, scenery and usually some daylight for the early stages of the decompression, Turner is black, silty with no sand slope, scenery or daylight. We decided following the last dive that 4 support teams would be more effective than 2 teams. The first team would handle the initial meet and greet and extract gear. The second team would meet at the 70ft gas switch and extract any remaining equipment. The third team would handle RB80 extraction in the trough at 40ft before handing off to the basin team for the final 3 hour ascent to the surface. Everything was working as planned with regular visits and gear being removed in a timely and coordinated fashion. As Jarrod and I pressed the 70ft stop and began the multi-hour ascent to the trough we were feeling tired but reasonably good. At 60ft I began to notice the scrubber on the RB80 breaking through which was expected and I made the best of it knowing I could switch to open circuit at 50ft and the RB80 would be off at 40ft. At the same time I began to feel hungry and slightly dehydrated. The Camelbak on my 70ft bottle was empty when I picked it up but I figured I could make it to 40ft and ask the support team to bring in a replacement. Food was also waiting at 40ft. It had been 14 hours since we left the surface and aside from some energy gels there were few options in terms of eating anything. We had the 120ft trough in Wakulla for a quick snack but no such option until 40ft in Turner. As we began the ascent to 50ft I started to feel worse and switched to open circuit. My stomach was seriously upset about something in addition to being dehydrated and hungry. We had pushed the 70ft and 60ft stops so I knew a short stay at 50ft would not be a problem as I opted to move for the trough and get something to settle my stomach. Jarrod followed me up knowing something wasn’t quite right and we quickly worked together to extract some food from the tubes as the support guys peeled the RB80’s off us. The support team delivered a full Camelbak from the surface and we settled in for a longer than planned but certainly memorable 40ft stop.

The final ascent to the surface at Turner in zero viz is a classic WKP experience. Fortunately the obligation for 390 minutes is the same as the 210 minute profile. The support guys paired up and stayed with us as the rest of the team extracted the final bottles and RB80’s from inside the cave. We surfaced at 5:00am Sunday morning to a satisfied, yet weary support team. Another successful run and a total team effort as the group packed us up and we pulled out with the sun coming up. At 8am I phoned George from Perry knowing he would appreciate the call and was one of only a handful of WKPP divers that knew what it meant to score another mile in Turner. “Is it still headed towards Wakulla?” was all he wanted to know.

Huge Thanks:
Mark Messersmith, Mark Garland, Doug Mudry, Kell Canty, Shellie Foss, Todd Leonard, Robert Bognar, David Doolette, Jim Miller, Jackie, Brian Swearingen, Hunter Swearingen, Pina Porceddu, John Rose, Chris Werner


Turner Sink and Leon Sinks were still going strong and while we did not match the 6,000ft added on June 3, we managed almost another mile of cave heading south-southeast towards Wakulla. We were closing the gap and the reality of connecting the Leon Sinks and Wakulla Cave Systems was seriously within reach. The data was immediately plotted and confirmed Leon was closing in on Wakulla. The straight-line distance was now less than 2 miles. If conditions began to improve in Wakulla, it was the preferred location to push north and more importantly “upstream.” The decompression logistics were also more favorable. Lessons learned on this dive would require that we consider placing a deep trough, a deco RB80 and taking food and hydration planning seriously. Post dive burn testing also confirmed that we had pushed every scooter harder than they had been pushed before. Dive 3 would require some more horsepower.

Director’s Note

Upon assuming the role of Project Director from George Irvine in 2003, there were 4 goals I wanted to achieve before turning over the keys.

  1. Build a stronger base of experienced, capable, focused divers and professionals to handle the unknown requirements of future WKP exploration
  2. Leverage existing team resources to facilitate the research that was about to explode in the WKP
  3. Assist local, state and federal resource managers with policy development and public education efforts regarding the cave systems within the WKP
  4. Connect the Leon Sinks Cave System to the Wakulla Springs Cave System

#1 and #2 were already paying dividends thanks to senior members within the team who were stepping up and getting it done. #3 was on track and building momentum each year. #4 was perhaps 2 dives and 2 miles within reach and with Jarrod sharing the same level of motivation it was only a matter of time. I had not yet considered pushing Wakulla to the Gulf of Mexico but perhaps there was room for a #5 at some point.

It is worth noting that over the past 3 months the WKPP has made a series of incredible dives in terms of distance, depth, exposure and new exploration. I consider exploration to be the primary mission of the WKPP and to safely and effectively explore these extreme environments requires hard work, preparation, motivation, sacrifice and teamwork. I remain mindful of those before me who provided the basis for what has become, strangely enough, commonplace. In truth, it is far from commonplace but reflects the contributions made by hundreds of team members over the years and most notably former WKPP project directors Parker Turner, Bill Gavin and George Irvine. As we reflect upon the accomplishments of the past 3 months and for that matter, the past 16 years there is much to be proud in terms of individual and team accomplishments. Looking ahead, there is plenty more to do, great people in place to make it happen and wide open cave.

It has been my good fortune to have shared so many wonderful adventures with such good friends, and to stand in awe at what must truly be one of the great wonders of the world: The Woodville Karst Plain.” – Parker Turner

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