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Tuesday, June 04, 2013


On the Jämtland mountains, a group of spelunkers and cave divers are exploring what proved to be Sweden's longest underwater cave. Work has been going on for five eventful years in a struggle against the elements. Meters Deep snow, ice and cold are some of the difficulties faced by the group.


Cave diving in Bjurälven, Sweden

Bjurälven is a long limestone area in Jämtland, northern Sweden, where a river sinks and flows underground, emerging 3km lower down in the valley. The existence of large water-filled cave passages is certain. However, until recently nobody had managed to penetrate into the tunnels because of high water flow and the remoteness of the region, which is also a beautiful nature reserve. In early 2007 we performed our first winter expedition and our hope that the water flow would be lower was rewarded. The year after a larger expedition concluded that the area is unique to Sweden and which certainly contains Sweden’s longest underwater cave.
Now, together with geologists, marine biologists and nature photographers, we shall return and continue the exploration and documentation of Sweden’s largest underwater cave.

These are the most extreme diving conditions to be found in Sweden. Some passages are so small that the divers have to take off their cylinders underwater and push them ahead as they inch slowly forwards. The currents are still very strong even in winter and in places the divers must drag themselves forward using ropes. The water temperature is only just above freezing and as a wet diver climbs out of the water all equipment freezes instantly in temperatures which can dip below -15C. Snow at least a metre deep and frequent snowstorms add to the difficulties.

We are 15 participants coming from all over Sweden and 8 are experienced cave divers. Also participating are 2 still photographers and a film crew. Photography and filming will be carried out both above and below the water.

Results 2008
A total of 15 lectures have been given (at the Royal Institute of Technology, exhibitions, companies, diving schools and clubs). The most recent event was a lecture in Helsinki to an audience of over 300 people.
More than 10 articles have been published in a variety of newspapers and magazines, including Aftonbladet, Östersundsposten, Värmlandstidningen, Tidningen‐DYK, and various outdoor and camera publications.
TV coverage in both local and national TV news programmes. The trial underwater filming was a big success.

Who are we?Swedish Speleogical Society (SSF)
We are the national governing body for cave exploration in Sweden, responsible for mapping and registering all known caves in Sweden. We have a responsibility for spreading knowledge about the worth of spelological features and for ensuring their conservation. Speleology is also a science with links to geology, hydrology, zoology and climate science.

Expedition DatesMarch 2009 14th-28th
Stora Blåjön, about 200km north of Östersund, Jämtland, Sweden

Expedition goals
The main goal of the expedition is to explore water-filled cave tunnels to get a better understanding of how Bjurälven flows underwater from sink to spring.
To document the expedition with film and still photography
Exploration and survey (mapping) of newly discovered cave tunnels and any interesting speleological phenomena noted in the caves.
Produce a documentary film on the expedition aimed at national television.
Perform any specific tasks requested of us from interested researchers, nature protection agencies and local government or other civic organization.
PUBLISH RESULTS in newspapers, radio, TV, lectures and websites.
Mayan Rivier Maya Cave Diving


The Yucatan is noted for its famous spectacular formations and the amazing clarity of the water. In the Jungles nearby the ancient city of Tulum lie the 2 longest underwater cave systems known on earth. Creatures found nowhere else on the planet have been discovered in these caves.
Akumal is located in the middle of one of the finest regions for cave and cavern diving.
Cave diving is an extremely hazardous sport. For further information on "Cave Diving the Yucatan", refer to The Quintana Roo Speleological Survey (QRSS).
Cave Diving Rivier MayaThe Quintana Roo Speleological Survey (QRSS) supports safe exploration, survey and cartography of the underwater caves and cenotes of Quintana Roo, Mexico.
Created in 1990, the QRSS maintains an extensive archive of cave survey data for over 167 underwater caves and cave systems.
Cave Diving Water Sports Rivier Maya Association of Dive and Water Sports Operators
Asociacion de Prestadores de Servicios Acuaticos
APSA is the Riviera Maya's Association of Dive and Water Sports Operators. As APSA members, we are business professionals dedicated and committed to ensuring your safety, providing quality service, and preserving our precious environment.
El Proyecto de Buceo Espeleologico
El Proyecto de Buceo Espeleologico México y América Central [also known as "Mexico Profundo"] was founded by Jim Bowden in 1982 to advance knowledge of water filled caves and related features in México and Central America.
Exploration includes mapping and surveying as well as a study of the geology, biology, and hydrology of each system. The Proyecto incorporates advanced and diverse underwater technologies including the creation and utilization of customized dive tables, computer technology, side scanning sonar, rebreather applications, and studies in hyperbaric medicine and physiology.


Cenote Mexico Cenotes are fresh water pools connecting to submerged caverns and other cenotes. The standard formation is a round hole in the ground.
The cenote at Chichen Itza is a perfect example of the round sink hole formation. This cenote is probably the most well known and most visited as it is located at the Chichen Itza ruin site and easily accessible - but you can't dive here.
Often referred to as lagoons and ponds they are common all over the peninsula being most common in the Mayan Riviera. Of value to the early inhabitants these ponds were a source of fresh water and their connection to the source was of a mystical nature.
If you fly over the peninsula you will observe that whereever you see a cenote you will see the outline of ancient villages long gone.
Rivier Maya Cenote

SOLUTION CAVERN - Naturally acidic groundwater seeping through cracks in the limestone bedrock dissolves areas of softer rock lying beneath the hard surface crust. Over time, this process creates large underground caverns roofed with only a thin layer of surface limestone.
YOUNG CENOTE - As erosion continues, this thin roof eventually collapses, leaving an open, water-filled hole.
MATURE CENOTE - Over thousands of years, erosion gradually fills the cenote with organic and mineral debris, reducing its depth. The Cenote of Sacrifice is currently in this stage.
DRY CENOTE - As erosion continues, the cenote may completely fill, becoming a dry, shallow basin supporting trees and other vegetation.
Cenote diagram and description Courtesy of the Science Museum of Minnesota
There are a number of reasons that make cenote diving attractive to the diver.
Diving conditions are not effected by weather.
Moderate water temperature [77f].
Barely discernable currents.
Large caverns and passageways.
Excellent underwater visibility.
There are two distinct forms of cenote diving:
Cave Diving
Swimming into a cave beyond the reach of natural sunlight.
Cavern Diving
Staying in sight of the entrance of a cave within the realm of natural sunlight.
To cavern dive a diver must either be a certified cavern diver or be accompanied by a certified cavern diver. Most accessible cenotes open to the public are equipped with a permanent line to serve as a reference on a tour.
All necessary equipment for open-water diving is needed as well as two battery lights and a line reel.
Cavern diving courses involve two days instruction and four dives. A full cave diving course is taught over a week with a minimum of 14 cave dives.
Specialized training agencies include:
NACD National Association of Cave Divers
NSS National Speleological Society
There is an excellent book on the Yucatan's cenotes called: "Cenotes of the Riviera Maya" by Steve Gerrard [publisher unknown].
Not all Maya Riviera dive operators are qualified cave diving guides or instructors. Be sure to check before you go diving.


Cenote List courtesy of PlayaInfo
Chac Mool (Claw of the Jaguar)
Location: 22 km south of Playa Del Carmen/Almost across from Puerto Aventuras.
Description: 2 cenotes. Large cavern zone with beautiful views of jungle from inside cavern.
Open: 10-5 daily.
Facilities: Bathrooms, Restaurant.
Snorkeling: Yes. Larger of 2 cenotes offers view to large room.
Entrance Fee: Yes.
Ponderosa (El Eden)
Location: 3 km south of Puerto Aventuras.
Description: Exceptionally beautiful. Short walk on path takes you to Coral Cenote, which has a large island in the center of it.
Open: 10-5 daily.
Facilities: Bathrooms
Swimming: Very easy access. Nice overhang with tree that can be scaled to jump into cenote.
Snorkeling: Excellent. One of the most popular snorkeling sites. Unlimited visibility. Wide variety of fish, eels, turtles & aquatic plant life.
Entrance Fee: $5 US.
Chikin Ha (Points of Direction)
Location: 5 km south of Puerto Aventuras just before Xpu-Ha/Across from Barcelo Maya Hotel/Long way down bumpy road.
Description: Footpath through jungle will take you to some other cenotes – one is big & almost dry with lots of fossils.
Facilities: None.
Swimming: Can swim through tunnel to underground air chamber.
Entrance Fee: Yes.
Kantun Chi
Location: Just past Chikin Ha Cenote.
Description: 4 mostly half dome cenotes (Kantun Chi, Zaskaleen, Uchil Ha, Zazil Ha) along a series of light jungle trails. Most remote one has ancient looking Mayan temple next to it. Several tours stop here.
Facilities: Restaurant, bike rentals, horseback riding, small zoo.
Swimming: Not very inviting.
Snorkeling: Yes. Rental equipment available.
Entrance Fee: $10 US.
Location: Just past Kantun Chi/Close to highway.
Description: Beautiful, very primitive & rarely visited. Good for hanging out. Will probably have place to yourself. Likely to see more locals than tourists.
Facilities: None.
Swimming: You can dive into cenote from 3.5 m (15 ft) tall ledge.
Entrance Fee: 25 pesos.
Location: Just past Cristalino Cenote/Close to highway.
Description: In light jungle setting with more open air/sunlit than Kantun Chi, which creates more algae.
Facilities: Snackbar.
Entrance Fee: 30 pesos.
Taj Mahal
Location: 26 km south of Playa Del Carmen/5 km south of Puerto Aventuras/Just south of Xpu-Ha.
Description: 4 interconnected cenotes.
Open: 10-6 daily
Facilities: Bathrooms, Restaurant.
Snorkeling: Advanced. Requires swimming 5 m underwater under a rock wall to come into a large open cave with that has light shining through from ceiling above.
Entrance Fee: 40 pesos.
Dos Ojos (Hidden Worlds)
Location: 48 km south of Playa Del Carmen/3 km south of Xel-Ha/On right 4 km down dirt road.
Description: Part of Nohoch Nah Chich cave system. Location of filming for Imax Journey into Amazing Caves documentary.
Open: 10-5 daily
Facilities: Bathrooms, restaurant.
Snorkeling: Superb. Very popular. Stalagtites & Stalagmites everywhere.
Entrance Fee: $10 US/$25-40 US for snorkel tours.
Temple of Doom (Calavera/Skull)
Location: 2 km from Tulum on road to Coba on right/Very rugged rocky unmarked jungle path approximately 50 yds from road.
Description: 3 holes in ground (one 30 ft & two 4 ft in diameter) create skull shape, hence the name. Shaded by thick jungle canopy.
Facilities: None
Swimming: Great. 10 ft drop down into cenote. Rope swing & ladder – though may want to bring your own rope just in case.
Gran (Sac Aktun/White Water)
Location: 5 km from Tulum on road to Coba on right.
Description: Ladder steps lead to half moon shaped cenote decorated with small passages & openings. One of most popular sites. Good for all ages. Shallow on one side/deep on other. Famous for brilliant speleothem decorations & crystal clear water.
Open: 10-5 Daily
Facilities: Bathrooms
Snorkeling: Fun. Fantastic. Spectacular. Paradise.
Entrance Fee: 50 pesos.
Car Wash (Aktun Ha/Water Cave)
Location: 8 km from Tulum on road to Coba/4 km past Gran Cenote on left.
Description: Can drive right in approximately 30 m (100 ft) to cenote & locals used to wash vehicles here, hence the name.
Open: 9-5 Daily
Facilities: Bathrooms
Swimming: Very easy access. Like a small lake. Good. Fun.
Snorkeling: Good in winter months. Too much algae growth in warmer months. Many small tropical fish.
Entrance Fee: 20 pesos.
Cristal (Naharon)
Location: 4 km south of Tulum on right.
Facilities: Bathrooms
Swimming: Great
Snorkeling: Great
Entrance Fee: Yes. Includes entrance to Escondido across the street.
Escondido (Mayan Blue)
Location: 4 km south of Tulum on left/Across from Cristal Cenote/2 km walk in Jungle.
Description: Tarzan & Jane style. Beautiful, crisp, clear, secluded. One of least known.
Facilities: Bathrooms
Swimming: Good
Snorkeling: Good. Some great stone formations.
Entrance Fee: Included in Cristal entrance fee.

Cave diving in the English style

Cave diving in the English style
Many people have recently received courses of “cave diving” or “cave diving” and dived into the warm and clear caves in places like Mexico, Florida, Dordogne and Mallorca. These areas provide an easy cave diving, interesting and enjoyable. There are significant differences between these areas and the United Kingdom.
There are some things we want to explain to anyone planning to dive in caves in the UK. Things we think you should know …
Firstly, only a small proportion of the British Isles is composed of limestone, which form most of the caves. Therefore, there is a very limited number of places to dive in caves, of which only a handful are reasonably easy on your physical access, combined with extensive underwater passages and occasional “good” (eg more than two meters) visibility . Most of them require you to be a caver fact and law, and would need to have enough ropes and ladders, and know how to use them safely (including skills in Single Rope Techniques). As some of the caves can be more than four kilometers of the road, dozens of meters deep, with long creeping along the ground and other obstacles, you may need to assemble a team of cavers to carry your gear to the dive site. And, of course, need to know where is the entrance to the cave!
Virtually all dive sites in caves are on private land. This means that visitors must obtain permission from the owner before your visit. Some owners have installed physical barriers (eg locked doors) to prevent access, and may show those who pass their land fore the wrong side of a 12 gauge! Ever, can the owner do not worry if people visit the cave (or prefer not to know of the visits), but most of them simply like to be politely asked permission to visit the cave. Ignore this label may mean that the cave was closed permanently (guaranteeing the hostility of all the cave divers in the UK).
The only real way to find out the current access arrangements may be asking the local active members of the CDG. They may also have knowledge and experience of the meteorological effects of time in the cave in question and whether the cave will be flooded, have good diving conditions, what kind of visibility we can expect, what is the status of the guide wires, etc..
Most scans are performed by an individual or a small group of divers working together on a specific project, usually after investigating the geology, hydrology, etc.. and previous dives in place (with the important Sump Index, the journal of the CDG and publications of the clubs in caves). Divers then publish their findings in the journal of the CDG or sent to his publisher for his “secret file” (to be published at a later date or most appropriate) to share all this with the whole community of the caves. It is also hoped that a study (flat section) of any new discovery should be published in the Journal of the CDG.
The other divers etiquette dictates that no “hack” the project of someone while work continues. Therefore, it is individual responsibility to disclose that is developing a project, and also when the work is completed, tell people to “open season” back in the place in question.
For safety and convenience of others, any diver who finds a trap lines under conditions different from those previously published, must report changes to the editor for inclusion in the magazine.
Now look at the equipment and techniques. Many divers have adopted philosophies Hogarthian / Doing It Right promoted by WKPP, GUE, and so on. Without question, these principles are right for upwelling large, deep, easily accessible and open water sites in which they dive. The value of these techniques and equipment configurations is illustrated by the remarkable explorations carried out with few accidents. To quote the old adage, the proof of cheating cotton.
Unfortunately, such a configuration of equipment and techniques can not be used in British cave diving. Let us explain why …
For starters, most of the sites in the United Kingdom are inaccessible to divers who used bottles mounted on the back: very simple: do not pass through the halls of the cave. Therefore, the discussion of short and long hose or a place for the light, and so on. Does not arise. And you can leave at home the torpedoes! Here, the chordate is vital and the bottles side are de rigueur.
Although the water temperature is always cold (7 º max, 4 ° usually), wet suits are often carried in many traps. The large volume and restricted mobility of dry suits in a cave, and the likelihood of overheating and damage, precludes its use in all sites except the easiest access. The exceptions are long and deep traps, with a long way into the cave, where the usual equipment is worn cave to reach the dive site, transporting the dry suit and putting it after reaching the trap.
Rivers in the caves are often stained with peat and carrying amounts of sediment and organic matter, so the visibility of one or two meters is considered quite reasonable / normal, and three or four feet is excellent (but sadly very rare ). Larger water flows also mean more stress and strain on the lines, so a thickness of 4mm. is considered the minimum, and no wonder that of 6 mm. We have even put galvanized steel chain 1.25 cm. in a cave, and the floods just devoured the string of caves 11 mm. Consequently, thicker lines imply that the reels have to be sufficiently robust.
The beautiful aluminum spools with plastic housing you will see in many stores advertise “tek diving” will probably last about five minutes in the UK (apart from that you can not put any strings on them appropriately. The sweet, thin rope that come loaded these reels would be a threat in a sump in the UK.
In the next place in the UK, always wear a helmet! We guarantee that your head will hit the ceiling of the cave at least once during a dive, and some of the traps closer, will be constantly banging against the rock ceiling. It is also a very practical thing to mount lights on it, so you can see something (even a light brown and a line pressed against your skin) while you are negotiating with some of the traps less complacent. Usually carry two twenty-watt lights, lamps with ten degrees of opening angle, and two or more focusable flashlight batteries 6C in the hull.
The flashlights and head entail problems naked here. Most cave divers in the UK carry a minimum five different light sources on a dive, and all are mounted on the hull.
You’re probably beginning to realize why the Cave Diving Group members seem to discourage people from diving in caves in Britain. If you tell the truth, underwater caves in the UK can rarely be described as a pleasant environment. Sure you can get satisfaction for their work in a well-executed dive, but do not expect to see what you see in the pictures in magazines …
Upwelling British have a horrible reputation. In response to the British impressed by their progress and the distances explored, Olivier Isler said once: “Here in the Dordogne, the corridors are large, clean, warm water, so mamboing here is easy. But I know that in England the caves are very small, very cold water and you can not see anything. That’s very difficult and dangerous conditions. “This from a man who has broken world records in cave diving.

Silver Springs

Silver Springs of Marion County in central Florida is the largest and one of the most well known of Florida’s first magnitude springs, with average discharge of ~ 766 cubic feet per second (cfs) (or over 550 million gallons per day).
Image of The glass bottom boats await visitors at Silver Springs' main spring.The glass bottom boats await visitors at Silver Springs' main spring. © Harley Means / FDEPMain Spring, Blue Grotto, and The Abyss are collectively known as The Silver Springs Group and form the headwater of the Silver River. Below the head spring area, numerous smaller springs add additional discharge within the first half-mile of the Silver River. This scenic river is the single largest tributary of the Ocklawaha River.
Timucuan Indians settled around Silver Springs in the early 1500s. They were soon invaded by the Spaniards and eventually succeeded by Seminole Indians. The Seminoles, led by Chief Osceola, eventually retreated to southern swamps when pressed by the US Government in 1835. By the 1850’s, barges carried cotton, lumber and nonperishables up the river to the growing community of Ocala. In 1860, the first steam boats made their way upstream, and from that point on, people flocked to visit the natural beauty of Silver Springs.
Flowing at over 766 cubic feet per second, Silver Springs is the largest first magnitude spring in Florida.
Silver Springs has become an internationally known tourist attraction due to its naturally clear water, healthy submerged aquatic vegetation, abundant fish and other wildlife, and its famous glass bottom boats. In addition, the spring’s crystalline water has provided the perfect underwater backdrop for many Hollywood films and television programs including six Tarzan films, Seahunt, Mutual of Omaha’s Wild Kingdom, The Discovery Channel and many others.
Today, land adjacent to the headspring is part of the Silver Springs theme park which is owned by the state, but leased to a private operator. The park draws crowds who come to watch a variety of wildlife shows, enjoy the amusement rides, and explore the springs on the glass bottom boat rides. Silver Springs Park is contiguous with the Silver River State Park where access with boats, canoes and kayaks is possible.
Image of An anhinga dries its feathers on a roost along the Silver River after a successful dive for dinner.Zoom+ An anhinga dries its feathers on a roost along the Silver River after a successful dive for dinner. © Harley Means / FDEPHuman impacts
In the past several decades, changes have been observed and measured in the Silver Springs hydrological system. These changes in water flow, water chemistry, and ecology of the spring system were well-documented in “Fifty-Year Retrospective Study of the Ecology of Silver Springs, Florida”, by the St. Johns River Water Management District.
The dominant change in the water chemistry has been an increase in nitrates from an average background level of less than 0.05 milligrams per liter (mg/l) to an average above 1 mg/l which represents about a 20- fold increase. There is also concern about a possible decrease in water clarity, compared to past observations. The main sources of nitrate in the Silver Springs Group can be broken down into inorganic and organic sources. Based on the land use in the springshed, inorganic nitrates could come from fertilizer applied to pastures, golf courses, lawns, and crops; organic nitrates come from wastewater from septic tanks and municipal wastewater application sites and livestock, such as the large number of horse farms in the springshed.
During this same time period, the plant and animal life of Silver Springs and Silver River has changed, also. An increase in algal growth has been documented on the white sandy bottom and the dominant submersed aquatic vegetation (SAV), strap-leaf sagittaria (Sagittaria kurziana) and eelgrass (Vallisneria americana) in the spring run. There has been an overall decline in biomass of several species of fish including catfish, mullet and gizzard shad since the 1950s. Large numbers of an invasive nonnative sail-fin catfish have become established in the spring run.
There is an apparent measured decrease in flow from the Silver Springs complex, although there is some uncertainty about both its extent and cause. The St. Johns River Water Management District is expected to set minimum flows and levels in 2013 to prevent significant harm to the water resources or ecology of the springs.
Other stakeholders within the Silver Springs recharge basin have already taken actions that either directly or indirectly affect the restoration of the springs, ranging in scale from individual water conservation efforts to modified agricultural practices, to county-wide ordinances. The Silver Springs Basin Working Group, established in 1999, was the original forum for stakeholders representing federal, regional, state, and local agencies, local governments, the business community, agriculture, environmental groups and other concerned citizens to take restoration actions. Due to legislative budget cuts, the working group funding was cut, but restoration efforts continue through the State Total Maximum Daily Load (TMDL) and Basin Management Action Plan (BMAP) process.
One initiative supported by the working group was the acquisition of a 4400-acre property north of Silver Springs, purchased by the state in 2007. The purchase kept this especially vulnerable property in a natural condition and prevented pollutant loading from any potential development of the area. The property is now being managed by the state Division of Forestry as Indian Lake State Forest.
Marion County has used information from groundwater travel time studies and other research to establish spring protection zones for Silver Springs and, Rainbow Spring. It has also adopted two spring protection provisions in its comprehensive plan. One provision addresses septic tank and waste water treatment plants in the spring overlay zones for Silver and Rainbow Springs and the other addresses the use of fertilizer in non-agricultural settings in the county.
Hydrogeology of Wakulla Cave, Floridan Aquifer, north Florida
- from Kincaid, T.R., 1999, Morphologic and Fractal Characterization of Saturated Karstic Caves, Ph.D. Dissertation, University of Wyoming
Figure 1 (Click on the image for an expanded view)
Map of Wakulla cave and surrounding topographic features, Floridan aquifer, north Florida. Topography is from the USGS Crawfordville East, FLA. (1972) topographic quadrangle. Regional hydraulic gradient is south toward the Gulf of Mexico. A local ground water divide crosses the conduits and is marked by a broad zone of low ground water velocities. The southern conduits convey ground water toward the Gulf of Mexico while the northern conduits convey ground water to Wakulla spring.
Wakulla cave is comprised of a dendritic network of conduits of which 8,770 m have been surveyed and mapped (Figure 1). The largest conduit, labeled A and O on Figure 1 trends south from the spring / cave entrance for over 5.5 km (Jablonski, personal communication) of which 3.2 km have been mapped. Five secondary conduits labeled B, C, D, K, and M on Figure 2-5, measure 4.3 km in combined length and intersect the larger conduit. Eleven smaller conduits measuring 1.2 km in combined length connect to the secondary conduits. Most of the conduits have not been fully explored (Jablonski, personal communication).
The conduits are characterized as long tubes. The diameter and depth of any tube is consistent through space but individual or joining tubes can be divided by larger chambers of varying geometries. Conduit width is consistently larger than the height and the trends of the conduits do not follow noticeable fractures.
Water velocities in the smaller conduits were variable but sufficiently high to impede swimming against the flow. An average velocity of approximately 1 m/sec was estimated by calculating the rate at which a resting diver was propelled in the down-gradient direction. Water velocities in the largest conduits were smaller but remained large enough to propel a resting diver. The distribution of water velocities throughout a cross-sectional profile of the conduits is commonly variable wherein the water moves slower along the upper part of the conduit than through the center of the conduit. Scallop marks on the cave walls were observed throughout the cave and indicate the persistence of large ground water through-flow velocities for an extended period of geologic time.
The pattern of ground water flow through Wakulla cave is complicated by the fact that the largest conduits trend down-gradient from the spring discharge point. Flow directions compiled from observations made by cave divers indicate the presence of a ground water divide that crosses the cave between conduits D and M (Figure 1). Reduced ground water velocities encountered in conduit A after the junction with conduit D indicate that the divide is better characterized as a broad zone that crosses the cave at a distance of between 1 and 2 km from the spring. Variations in ground water velocities observed at different times throughout the divide zone indicate that the location of the divide fluctuates.
Direct connections to surface water sources are indicated in conduits A, K, M, and O by water clarity reductions that occur in as little as one day following local storms or prolonged regional precipitation (Jablonski, personal communication). Even during periods when turbid water discharges at the spring, clear water was typically observed discharging into conduit A from conduits B, C, and D (Jablonski, personal communication). Uranium isotopic compositions measured by Macesich and Osmond (1989) support that observation by showing that conduit A has a surface water signature while conduit B has a signature typical of regional ground water.
Genesis (Hypothesis)
Wakulla cave is a branching flow-dominated cave that has developed in the Floridan aquifer under the Woodville karst plain of north Florida. In terms of the proposed model, the cave has evolved into a flow-dominant stage wherein the conduits connect recharge sources with a spring. The geologic processes active on the Florida platform that have affected the development of Wakulla cave include, deposition of carbonate and siliciclastic rocks, sea level fluctuations, and subsequent erosion of the siliciclastic rocks that had provided an upper confining layer to the Floridan aquifer.
The Florida platform extends for more than 200 km into the present Gulf of Mexico and is defined by the 300 ft bathymetric contour (Figure 2). Carbonate sedimentation on the northwestern part of the platform was continuous between mid-Cretaceous and late Oligocene times (Scott, 1992). During the Miocene Epoch, siliciclastic sediments were transported onto the platform by rivers and distributed by longshore and other currents (Scott, 1992). Subsequent subaerial exposure resulted in the evolution of the carbonate rocks into the Floridan aquifer for which the overlying Miocene siliciclastic rocks, described as the Hawthorne Formation, provided a laterally extensive confining layer.
Sea level fluctuations have caused transgressions and regressions over the Florida platform several times since the deposition of the Hawthorne Formation. Submarine springs on the Florida platform (Figure 2) indicate that karstification had established preferential flow routes through the Floridan aquifer prior to the last sea level rise.
Landward erosion of the Hawthorne Formation exposed the underlying carbonates to infiltration of surface waters and caused the development of karstic ground water flow systems. The erosional boundary of the Hawthorne Formation creates a prominent topographic scarp known as the Cody Scarp (Figure 2). Surface drainage across the scarp and onto the exposed carbonates creates a zone of extensive karstification marked by numerous caves, sinkholes, and disappearing rivers (Ceryak, 1981; Spangler, 1981; Scott, 1981; Lane, 1986). The zone of karstification has followed the landward migration of the scarp leaving remnant caves and sinkholes on the evolving low carbonate land surface. Fossil and archeological artifacts discovered inside Wakulla cave but close to the spring discharge (Figure 3) indicate that the shaft that currently localizes Wakulla spring is one of these remnant sinkholes.
These facts combined with the present pattern and flow characteristics in Wakulla cave indicate that the largest conduits in the cave developed during a period of lower sea level and more seaward extent of the confining layer. Discharge from the aquifer was through the present submarine springs. Recharge was through a sinkhole that is currently Wakulla spring and was localized by the paleo-extent of the confining layer. The paleo-flow system caused dissolution of rock from the aquifer that culminated in the development of a flow-dominated cave that connected the sinkhole with the down-gradient spring(s). Precise timing of the cave development cannot be constrained beyond any of the periods of lower sea level that post dated the deposition of the Hawthorne formation during Miocene time.
Following the retreat of the confining layer and sea level rise, regional hydraulic gradients reduced forcing the evolution of the flow system into the current condition. The sinkhole that was the predominant source of recharge evolved into Wakulla spring. New sinkholes and karstic depressions like the Leon Sinks sinkholes developed farther up-gradient in the proximity of the retreating confining layer. The smaller conduits in Wakulla cave developed as a consequence of dissolution along flow paths connecting the newer sinkholes with Wakulla spring.
The original conduits comprising Wakulla cave remained in the aquifer however, and provided preferential flow paths that connected the newly formed Wakulla spring with the down-gradient springs that were drowned by the rise in sea level. A ground water divide has developed across the cave where flow converging on the conduit from the northern part of the Woodville Karst Plain discharges at Wakulla spring while flow from the southern part of the region enters the conduit and flows farther down-gradient to the submarine springs.
Figure 2. (Click on image for an expanded view)
Map of the Florida peninsula delineating the lateral extent of the Florida platform at the 300 ft water depth contour and showing the location of submarine springs relevant to the hydrology of the Woodville Karst Plain, north Florida. Location of Wakulla spring is shown relative to the approximate present position of the Cody scarp which marks an extensively karstified region in the transition zone between unconfined and confined conditions in the Floridan aquifer. Map is from Lane (1986).
Figure 3. (Click on image for an expanded view)
Location of fossil and archeological artifacts near the entrance to Wakulla cave at Wakulla spring, north Florida. Fossil and artifact locations are from Olsen (1958). Cave profile is from data collected by the Woodville Karst Plain Project cave divers.