Grotte de La Mescla – “A Dive Rite of Passage”

by Geoffrey May

I was ecstatic as I punched “send” and officially bought my airline tickets to the French Riviera. I really would be flying to La Cote d’Azur on the Mediterranean Sea, and my heart pulsed wildly as the primal urge to go cave diving began to kick in.

Immediately I began banging my computer keys in the quest to find a great cave to explore. My first email was to Segytek, the Dive Rite Distributor for all of France. They were kind enough to forward me the email address of their friend and fellow cave diver, Frederic Bonacossa. Frederic lives close to Nice and knows all about the diving in the area. From the moment we established contact, Frederic proved to be the ultimate guide. We began our email correspondence exchanging niceties, but soon enough we were beginning to devise our plan. My first questions: “What is the must-do cave dive in the area?” And, “How soon can we go?”

Of course, I had to tell Frederic that this would be primarily a family trip, with my beautiful wife and two sons, but he understood that I was not capable of getting so close to the French cave systems without being pulled underground for a little exploration. Frederic described the many options within a 1-3 hour radius of the southeastern city of Nice but quickly began to zero in on the dive we needed to do. His excitement was obvious, even in the silent and colorless context of electronic mail. He detailed the formations and stalactites and how this cave system “La Mescla” was one of the last completely unexplored systems in the area. The cave began and continued deep into the mountainside of the French Alps, and Frederic went on to say that the end of the cave had yet to be found. Few divers have access to this gem because of the location and difficult access, although it does have a long history of exploration that goes back to 1897. He told me that it would not require any “climbing gear” (huh?) and was going to be an “easy” dive that would take us approximately fours hours to complete.

Okay, the four hours seemed appropriate as there would be about an hour’s drive from our villa to the site, but the “climbing” reference deserved further questioning. He responded by saying that we could just walk right to the water and it would not take too long…as opposed to using any ropes, carabineers, or harnesses. Sounded good to me so I thought nothing else about it. Just like we do here in Florida: simply back the SUV up to the spring, maybe a short walk to the water hole, and then plop in.

Frederic told me that the water in La Mescla is relatively warm water (approx 65 degrees) because of the geothermal activity in the region and suggested a wetsuit no thicker than 5mm. I was somewhat reluctant to give up my 905 drysuit as I have become accustomed to maximum comfort during my dives, but it rarely makes sense to disagree with the natives no matter where you travel. He remarked that we would pass through a halocline in some parts where the geothermal salty water seeped through the seemingly solid walls of the mighty Alps. This seepage is referenced in the local name for the system, La Mescla, meaning “mixed,” referring to the mixture of fresh and salt water.

Frederic explained that this cave is one of the more interesting in the region because the carved limestone has been vertically rotated. The ground has literally twisted like a corkscrew over time. This enabled concretions and formations that were once above the water line to now exist under the water. He continued to entice by explaining that it is a “sump” dive; that is, there would be times during the dive when we would surface and walk a bit to the next deep entrance below ground. My anticipation grew with every description and he had me hooked. Yes, this sounds like the place!, Lets go! Day? Time?

Frederic said evening was best for this dive, so he would pick me up at 8 p.m. at our villa in Nice. “Eat dinner before the dive and plan to be home after midnight…” he wrote in the email. With anticipation burned into my brain, we made our last communication before I was to fly over. In addition to the cave dive I had also planned a wall dive off the coast of Nice so I would need to pack my gear accordingly. For this trip I chose the Transplate system mounted on to an aluminum backplate and the Rec Wing aircell. This would perfectly accommodate both the double 7 liter steel cylinders in the caves as well as the steel 95 for the open water dives. This combo proved to be the right choice. The French custom is diving independent doubles, so I set up my regulators and made the minor alterations required before we left.

Upon arriving in France I only had one evening to get over the jet lag before I would dive the cave with Frederic the following evening. I was determined to be well rested and ready for the dive, so I tried to prepare myself as best I could during my first 34 hours in France. We landed in Nice just after 10 a.m., so as we sped off in our rented Renault I was already thinking about a decadent and lengthy French lunch. As Nice is so close to France’s southern border, the local chefs are equally skilled in the gastronomy of neighboring Italy. After the lunch of my dreams consisting of delectable pasta with meat sauce seasoned perfectly we continued to our rented villa, on the eastern side of the grand port. We did some brief sightseeing in the afternoon, then surrendered to the jet lag and went to bed early. The following day was filled with sights and sounds and meals as well, but my mind was really on the cave dive that I would soon experience. 8 p.m. could not arrive soon enough.

Finally, it was time. Waiting on the street with my mesh gear bag slung over my shoulder, I began to look for my ride. Of course, I had no idea what Frederic looked like—with all the emails, not one digital photo had been exchanged—but I somehow remained confident that I’d be able to recognize any Frenchman driving around looking out the window for someone with Scuba equipment in their hands. Sure enough, at 7:58 a small two-door “Citroen” rolled by with a dark-haired head hanging out the window. As he was not going slowly I quickly yelled “Frederic?…Frederic?” over the sound of the high-pitched exhaust.

“Oui, Oui, Frederic” he replied as he raced into the driveway after making a sharp left across oncoming traffic. This was the proper maneuver for the situation according to local custom. After the passing horns quieted down, we made our introductions and proceeded to load my gear into the hatchback. He flashed the cylinders he had managed to get for me and although I was thankful, I was somewhat taken aback at the sight of the seemingly ancient small steel cylinders with “rams horns” protecting the outdated Poseidon-like valves that stuck straight up. He had been unable to locate any double long cam straps, so he improvised with ratchet straps… which did the job but certainly had that jury-rigged look to it. We proceeded to get on the road, as we still had an hour’s drive ahead of us and we were both eager to get in the water. I do not think there was any silence in the car for the entire ride to the site as we shared stories about dives, talked about equipment, and ultimately planned our dive for La Mescla. Discussing depths, procedures, safety drills, equipment, configurations, and our dive plan for the evening, it was clear that we understood each other’s diving styles and confirmed that the evening was off to a great start. I stared out the window at the folds in the sides of the mountains and awed at the geological activity that is so different from my home in Florida. He soon warned me that we were getting closer to the site, then a few minutes later, he quickly pulled off onto the shoulder of a rather small two-lane highway. It seemed as if we had pulled over in a short emergency area for broken-down cars located just ahead of a tunnel through the solid rock. We hopped out of the car and Frederic began to explain the scene.

To our right we saw “Le Var”, a river running through the Alps that looked maybe six to twelve feet (two-to four meters) deep in the middle. It was big and wide but not deep. We stepped over the concrete barrier between our car and the steep shoulder that led to the river and worked our way down to the water, crossing a small railway that ran from Nice to the mountains. I wondered how this could be the entrance for our adventure, and I was quickly told that this was the final exit from the Alps of the water that we would be diving in. It was a cave entrance/exit maybe 30 feet (10 meters) high by 15 feet wide, and I could only see about 30 feet (10 meters) inside before the rock pinched down to a smaller hole. We knelt and tasted the fresh water that had a hint of salt in it. I snapped a quick picture and off we went, back up the hill to the car.

So, if this was not the entrance, then where was it? Back at the car, I looked around the rock wall that climbed high above on our left side and could not notice any visible entrances or even large cracks for that matter. Frederic assured me that the entrance was there, and we began a short walk back behind the car in the direction we had come from. After just 45 feet (15 meters) he stopped and began to use basic mountaineering skills to work his way up a path that, with some small rock outcroppings and scrub brush, may have been used by someone or some animal before. But it was certainly not a well-defined walkway. Tight and narrow and with a steep grade, the steps led us up and around a corner that revealed the cave entrance. It was not large. In fact it was an arch shape that was, at its highest point, not much bigger than an average man standing tall. Approximately six to nine feet (two-three meters) wide at the bottom, it was nonetheless the entrance to the next chapter in my trip.

We stepped into the entrance and followed the narrow cave for about 30 feet (10 meters) until we came to a prison-style iron gate that blocked our way. I noticed a sign on the rock beside the gate that proclaimed this a recognized dive site for use only by trained divers in association with the local cave organization of France, the French Federation of Speleology (FFS). I breathed in the damp cool air of the cave and noted an inviting aroma, then turned to head back to the car to get geared up. At the car we discussed the plan in depth and helped each other set up our systems. This gave each of us the opportunity to see what equipment the other was using, in case that information became more essential during the dive. I checked and double-checked my unfamiliar cylinders and felt confident that they would survive the dive. Although the ratchet bands were ugly, they were certainly solid and functional. As we donned our final gear, Frederic handed me a safety helmet with a head lamp wrapped around it. We would not need to use these in the water but they were essential for the walk to the pool. Tightening my helmet straps and checking my equipment a final time, I followed him back toward the rocky path that led to our adventure for the evening. In addition to all of his diving gear, I noticed Frederic also carried a large tire iron in his right hand. This would prove to be the key for the gate. It was my interpretation that everyone in the diving organization became aware of the size “socket wrench” that was required to open the lock so a distribution of keys to members would not be required. We use combination locks for similar situations in the States but again, I have found it best not to argue with the natives and their customs. After a little manipulation, the heavy gate swung open with a “creee-ee-eeek” that came straight from the old Sherlock Holmes features on the late show.

Working our way through the tight cave walkway we locked the gate behind us and left our car keys and the tire iron behind. It was clear that no one else would be diving here tonight, or any time soon by the looks of things. I quickly realized that few came into this cave anymore and even fewer got to dive here. As we began our walk, Frederic explained that about once a year a large group would come to dive here and continue to “push” the system in anticipation of finding the cave’s end someday. Using a multitude of cylinders, several different gas mixes, along with the latest in DPV assistance available, the team would strive forward annually on the quest. It was because of this that our walk to the water would be possible without specialized climbing gear. They had left several ladders behind at key junctions and also installed some homemade handholds from bent rebar directly into the rock in some areas as well. This would make the climb possible.

As we moved forward I quickly began to realize how naive I really was about what it was going to take to walk to the water’s entrance. The damp rock was made slippery by a thin layer of clay and mud that coated the outer surface. This made for a hazardous path that required full concentration with a set of doubles on. I focused on the hike at hand and soon realized that there would be many surprises ahead. The first came when the path began to incline at a steep grade. The ceiling overhead began to squeeze down as well, and the function of the helmets was soon put to the test. In some spots it was simply impossible to avoid contact with the hard rock walls. Careful with every step, we approached the first ladder. A 20-foot (seven meters) extendable was set up against the floor that dropped off below us and then continued about 15 feet (5 meters) down. This was the first drop down in elevation that began our switchback approach to the water. It became clear that we were zig-zagging back and forth in our path towards the water that was approximately 60 feet (20 meters) below the level of the road we had driven in on.

As we went deeper into the cave, I also noticed a fine misty haze that permeated the tunnels. Continuing on, we approached a second ladder that this time led us back up. While the weight of my equipment was becoming ever more noticeable to me, it did not deter my enthusiasm to reach our goal. Just as I started to mentally accept the extended hike in the mountain I was confronted with an unforeseen obstacle before me. The floor dropped away abruptly to a small pool of water nearly 45 feet (15 meters) below. The only way to continue on was over a four-inch wide piece of metal that served as the footbridge. A sturdy wire was suspended above to serve as a handhold, but careful concentration and perfect balance were required to hurdle this phase of the expedition. Frederic went first, which eased some of my fears, but now it was my turn. I approached the bridge cautiously and firmly grasped the damp, cold wire above me. I was not going to let go no matter what happened, I repeated in my head several times as I took the first steps forward. While the small steel plank felt secure enough, the art of balancing with two cylinders on my back made for interesting memories. I coaxed myself farther along and finally completed the 12 foot (4 meter) journey to safe hard rock on the other side.

Proud as I was, my heart pounding, I could not help but wonder about the next obstacle. “What could top that?” I thought. Soon enough I was rewarded with the answer. As we closed in on the wading pool where our dive would begin, the final obstacle loomed. The path rounded a corner and began a steep decline that wound down for nearly 60 feet (20 meters). As we were closer to the water now, the damp muddy rock seemed even more slippery, and one final cautious leg was in front of us. The ceiling pinched down again and with the walls closing in on us, it was impossible to walk upright or find any good handholds to use. The only experience I could only compare it to was walking down a yellow plastic slip-’n-slide as I did as a child. This time I had to manage the trick with two tanks on, and be sure not to slip or the end of the dive would arrive before it began.

Squatting down and sliding on my bottom, I realized, was not an option, and it wouldn’t look very cool either. I proceeded with caution, taking each step super slowly. I attempted to dig in with my neoprene booties but found that the rock did not lend itself to this approach. Searching for something to grasp onto, I found nothing. I simply had to continue and hope for the best. I was thinking about how I would fall, as that seemed the inevitable outcome at this point. Creeping along as Frederic watched from below me, I kept my focus and carefully proceeded forward. To my amazement I did not slip, did not fall, and made it to the bottom safely…Whew! We could finally see the shallow wading pool that would serve as the starting point for the evening’s adventure. One last ladder was in front of us that led down to the pool. The heat I had generated on the hike in was soon to be released as I made the final approach to the cool water. I had never before been so eager to sink into 65 degree water without a drysuit on. Being a thin-blooded boy from Florida, that is considered “cold” water for me. My apologies to all of our northern divers for the reference.

Finally, we had arrived. To my left was the downstream access that Frederic considered silty and dangerous and impossible to explore. He warned me not to let go of my fins as the flow would carry them away to the river, out the exit we had seen earlier, downhill from the car. The flow was down at this time of year so we did not have too much to worry about. We were going to swim into a siphon for our dive and we had planned our gas consumption accordingly. While we took a minute to let our heart rate drop, we began a final check of our gear and reviewed the plan. I was going to lead and simply follow the main line as far as we wanted to go, basically sticking to the rule of thirds. The dive was technically a siphon, so we altered this slightly for conservation. He informed me that we would eventually come to a chimney that dropped quickly to 180 feet (60 meters). To avoid an extended decompression time and because we were diving air, we both agreed to keep our maximum depth around 120 feet (40 meters). With a final check of my SPG’s I flicked on my SunSpot 10-watt HID and off we went.

I was determined to swim slower than normal in an attempt to absorb the beautiful surroundings as much as possible. We were off! The cool, clear water was instantly invigorating both physically and mentally as the underwater underworld of France was now coming into view for me for the first time ever. A slow, steady descent to 60 feet (20 meters) took the first few minutes, and the formations and makeup of the rock were the first things I was able to focus on. Following the “gold line” that was actually more like a white phone cable in some spots, (used in the old days to call assistance when deep divers were at decompression depths in sump 2) I swam steadily, keeping my piercing light bouncing back and forth slowly in front of me. A few minutes later while checking my gauges, I noticed the depth steadily decreasing. Now at only 20 feet (7 meters) in depth I looked ahead and could see the gradual ascent to the surface. Momentarily confused, I then remembered this was a sump dive and we must be nearing the first walking section. Sure enough, the rock bottom below me crept up and up until I could simply put my feet down and stand in the cavern we had entered.

Breaking the surface I poked my head up to see a room that could only be compared to fantasy cave scenes I had seen in Hollywood movies. Marvelous rock layers with spots of stalactites in certain areas and countless earth tones of color surrounded me. We spent only a minute here and exchanged few words. We continued walking the short distance to the next ground entrance and I signaled I was ready to continue. Sinking into the gin clear water again my eyes were eager to see what was next. The underwater rock kept my attention as we floated effortlessly through the chasms. The siphon was barely apparent but allowed for optimum SAC rates on the swim in for us both. Switching back and forth between regulators every five minutes, I was able to keep my air volume equal in both cylinders in case a complete failure occurred on either tank. I was conscious about the age of my borrowed equipment and took every precaution.

I noticed a quick back and forth light signal in front of me coming from Frederic, so I slowed and turned around to see what he wanted to communicate to me. He pointed to several cracks in the wall to my right and motioned me towards him. I soon realized that this was where the fresh water coming from the top of the mountain was floating upon our warmer and lightly salted water. As we ascended just a few feet, we passed through the visibility-altering halocline he had told me about. Like playful kids, we bounced in and out of the salty mixture with smiles on our faces. This is certainly an interesting experience underwater no matter what your age.

Having enjoyed that submerged tourist attraction, we both motioned that we would continue. Following the route, we continued to round several corners and countless hills and valleys as our depth varied between 60 and 120 feet (20 – 40 meters). Looking ahead, I noticed Frederic’s light signal again and anxiously wondered what he would point out next. Below us in the middle of the cave was a large mound of khaki colored clay that seemed innocent enough until further inspection revealed a plethora of tiny bones littered throughout. I would come to understand that this was a “bat cemetery” that had been in the cave for hundreds or even thousands of years. Generation after generation of bats had left layer upon layer of these bones for us to see.

There were areas where air pockets existed above us so I determined that the current lineage of small mammals were located above the water line in the ceilings. They must have had some other small entrance and exit to the cave that only they knew about. Swimming onward, we experienced several more exciting twists and turns. Rounding another bend in the rock, our depth neared 120 feet (40 meters) and I could start to see the deep dark chimney that loomed in front of me. The line cam to a tie off then darted straight down into the depths that would be unobtainable to us on this dive. Our bright HID lights shined nearly to the bottom, which was clearly another 60 feet (20 meters) down. To venture there would have required a completely different dive plan and substantially more equipment than we had. Just a moment or two looking around at this deepest penetration point for me and I signaled we would begin the slow swim back. Still nearly 300 psi (20 bar) from thirds, I had plenty of air.

As we turned the dive it was apparent the light flow in our faces would not be a factor. Careful to appreciate every moment, I swam slowly and peered carefully into every nook and cranny that I saw. Scanning the ceilings and floor alike, I took dozens of mental pictures at each juncture along the route. Passing the cemetery again … rocks that looked more familiar this time … then the halocline. It all seemed to go by so fast this time, and before I was ready to be finished we had reached the end of the first leg back. We surfaced into the open cavern zone, spending several minutes there this time before dropping back into the water again. Making the final 10 minutes of the dive, I kept a close eye on my Nitek Plus computer, careful not to miss a deco stop or ascend too quickly. While I came within four minutes of a deco requirement, the final stretch of the cave was relatively shallow and allowed essentially a swimming decompression before we would be required to surface. I could now see the floor rising towards us, so I checked my computer one more time and maintained a slow ascent. In fact I began to literally crawl along the rock bottom in an attempt to get every last drop out of the dive. My computer showed no deco required so I continued accordingly.

The dive was over. As I surfaced with a large smile, my second stage dropped out of my mouth into the water. Kneeling in the shallow pool, Frederic and I sat and talked for nearly 15 minutes, gushing about our adventure. As we managed the grueling climb out that evening, Frederic insisted on being the cameraman. He was able to snap several good pictures that showed off the countless wonders the underground cavern held. Although it may have been even more difficult than climbing in, the additional energy from the dive made the hike out a “walk in the park.”

I had once again been fortunate enough to experience something that very few people in our enormous population would ever have the opportunity to accomplish. Cave diving is one of the world’s most extreme sports and it inspires the most profound emotions that one can experience. The caves around the world wait patiently for us to venture into their hidden zones…. Dive it all!

Additional info: http://www.plongeesout.com/sites/cote-azur/alpes%20maritimes/mescla.htm